122 results on '"Timothy C. Cox"'
Search Results
2. Altering calcium and phosphorus supplementation in pregnancy and lactation affects offspring craniofacial morphology in a sex-specific pattern
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Mohamed G. Hassan, Christopher Chen, Hanan A. Ismail, Abbas R. Zaher, Timothy C. Cox, Alice F. Goodwin, and Andrew H. Jheon
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Male ,Mice ,Pregnancy ,Dietary Supplements ,Animals ,Humans ,Lactation ,Calcium ,Female ,Phosphorus ,Orthodontics ,X-Ray Microtomography ,Article - Abstract
INTRODUCTION: The effects on offspring craniofacial bone morphology and accretion because of altered maternal exposure to dietary components such as calcium (Ca) and phosphorus (P) are unclear. The objective of this study was to investigate the changes in offspring skull morphology and tissue mineral density (TMD), including sex-specific changes, with exposure to a maternal diet high in Ca-to-P levels during gestation and lactation in mice. METHODS: Time-mated FVB wild-type mice were fed a normal or experimental diet during gestation until weaning. The experimental diet contained a 3-fold increase in Ca and a 3-fold decrease in P (Ca:P molar ratio, 10.5) compared with normal mouse chow (Ca:P molar ratio, 1.5). The heads of 6-week-old control and experimental offspring mice were collected and scanned using microcomputed tomography. Three-dimensional geometric morphometric analysis was performed to analyze changes in craniofacial morphology. TMD measurements were also analyzed. RESULTS: We observed subtle changes and no significant differences between offspring control and experimental skulls when we compared all samples. However, when we separated skulls by sex, we discovered significant differences in craniofacial morphology and TMD. Experimental female offspring possessed skulls that were smaller, narrower transversely, taller vertically, and decreased in TMD. Experimental male offspring possessed skulls that were larger, wider transversely, shorter vertically, and increased in TMD. CONCLUSIONS: Maternal exposure to diet and increased Ca:P molar ratio during gestation and lactation led to significant, sex-specific morphologic and TMD changes in 6-week-old mouse skulls.
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- 2022
3. A mutational hotspot in AMOTL1 defines a new syndrome of orofacial clefting, cardiac anomalies, and tall stature
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Alanna Strong, Soumya Rao, Sandra von Hardenberg, Dong Li, Liza L. Cox, Paul C. Lee, Li Q. Zhang, Waheed Awotoye, Tamir Diamond, Jessica Gold, Catherine Gooch, Lord Jephthah Joojo Gowans, Hakon Hakonarson, Anne Hing, Kathleen Loomes, Nicole Martin, Mary L. Marazita, Tarja Mononen, David Piccoli, Rolph Pfundt, Salmo Raskin, Stephen W. Scherer, Nara Sobriera, Courtney Vaccaro, Xiang Wang, Deborah Watson, Rosanna Weksberg, Elizabeth Bhoj, Jeffrey C. Murray, Andrew C. Lidral, Azeez Butali, Michael F. Buckley, Tony Roscioli, David A. Koolen, Laurie H. Seaver, Cynthia A. Prows, Rolf W. Stottmann, and Timothy C. Cox
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All institutes and research themes of the Radboud University Medical Center ,Neurodevelopmental disorders Donders Center for Medical Neuroscience [Radboudumc 7] ,Genetics ,Genetics (clinical) - Abstract
Contains fulltext : 291896.pdf (Publisher’s version ) (Closed access) AMOTL1 encodes angiomotin-like protein 1, an actin-binding protein that regulates cell polarity, adhesion, and migration. The role of AMOTL1 in human disease is equivocal. We report a large cohort of individuals harboring heterozygous AMOTL1 variants and define a core phenotype of orofacial clefting, congenital heart disease, tall stature, auricular anomalies, and gastrointestinal manifestations in individuals with variants in AMOTL1 affecting amino acids 157-161, a functionally undefined but highly conserved region. Three individuals with AMOTL1 variants outside this region are also described who had variable presentations with orofacial clefting and multi-organ disease. Our case cohort suggests that heterozygous missense variants in AMOTL1, most commonly affecting amino acid residues 157-161, define a new orofacial clefting syndrome, and indicates an important functional role for this undefined region.
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- 2023
4. Altering osteoclast numbers using CTSK models in utero affects mice offspring craniofacial morphology
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Mohamed G. Hassan, Ricardo Vargas, Bin Zhang, Noah Marcel, Timothy C. Cox, and Andrew H. Jheon
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Otorhinolaryngology ,Surgery ,Orthodontics ,Oral Surgery - Abstract
Bone remodelling during development and growth is important for craniofacial integrity of offspring. The aim of this study was to investigate the changes in offspring adult skull morphology when the osteoclasts number was altered in utero, using three-dimensional (3D) geometric morphometric analysis (GMA).We altered osteoclasts number in utero via two approaches. First, we generated heterozygous CtskAltering osteoclasts number in utero affected the offspring adult skull morphology. Decreased Ctsk and osteoclast numbers were associated with a decrease in cranial vault height and an increase in mandibular body length. Changes in size and shape were observed with an increased number of osteoclasts in CtskThe findings of this study suggest that modulation of osteoclast numbers during pre- and post-natal development may be a previously unknown factor in the aetiology of skeletal malocclusions. An improved understanding of the factors affecting bone homeostasis during development and growth may help in the development of future therapies that would target the early intervention of skeletal malocclusion.
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- 2022
5. Survey of spiking in the mouse visual system reveals functional hierarchy
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Luke Esposito, John W. Phillips, Lydia Ng, Maggie Chvilicek, Kara Ronellenfitch, Corbett Bennett, Kael Dai, Peter A. Groblewski, John Galbraith, Jackie Swapp, Brian Hu, Ross Hytnen, Fuhui Long, Emily Gelfand, R.D. Young, India Kato, Linzy Casal, Greggory Heller, Jennifer Luviano, Xiaoxuan Jia, Ben Sutton, Michael A. Buice, Saskia E. J. de Vries, Shiella Caldejon, Sam Seid, Tamina K. Ramirez, Thuyahn Nguyen, Wayne Wakeman, Chelsea Nayan, Philip R. Nicovich, Roald Dietzman, Nicole Hancock, Colin Farrell, Carol L. Thompson, David Feng, Erika Jessett, Hongkui Zeng, Elizabeth Liang, Shawn R. Olsen, Kristen Turner, Jérôme Lecoq, Derric Williams, Katelyn Johnson, Jose Melchior, Stefan Mihalas, Hannah Choi, Sam Gale, Jennifer D. Whitesell, Ramakrishnan Iyer, Kat North, Melissa Reding, Dillan Brown, Yang Li, Kiet Ngo, Séverine Durand, Robert Howard, Amy Bernard, Anton Arkhipov, Julie A. Harris, Ali Williford, Yazan N. Billeh, Marina Garrett, Sophie Lambert, Tyler Mollenkopf, Arielle Leon, Marius Pachitariu, Michael Oliver, Nicolas Cain, Gabriel Koch Ocker, Daniel J. Denman, Justin T. Kiggins, Joshua H. Siegle, R. Clay Reid, Douglas R. Ollerenshaw, David Reid, Cliff Slaughterbeck, David Sullivan, Jed Perkins, Ruweida Ahmed, Daniel Millman, Jung Hoon Lee, Kyla Mace, Christof Koch, Andrew Cho, Nile Graddis, Timothy C. Cox, Peter Ledochowitsch, Miranda Robertson, Michelle Stoecklin, and Sarah A. Naylor
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0301 basic medicine ,Hierarchy ,Retina ,Multidisciplinary ,Neocortex ,Visual perception ,genetic structures ,Computer science ,Direct observation ,Visual task ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,medicine.anatomical_structure ,medicine ,Latency (engineering) ,Neuroscience ,030217 neurology & neurosurgery ,Coding (social sciences) - Abstract
The anatomy of the mammalian visual system, from the retina to the neocortex, is organized hierarchically1. However, direct observation of cellular-level functional interactions across this hierarchy is lacking due to the challenge of simultaneously recording activity across numerous regions. Here we describe a large, open dataset-part of the Allen Brain Observatory2-that surveys spiking from tens of thousands of units in six cortical and two thalamic regions in the brains of mice responding to a battery of visual stimuli. Using cross-correlation analysis, we reveal that the organization of inter-area functional connectivity during visual stimulation mirrors the anatomical hierarchy from the Allen Mouse Brain Connectivity Atlas3. We find that four classical hierarchical measures-response latency, receptive-field size, phase-locking to drifting gratings and response decay timescale-are all correlated with the hierarchy. Moreover, recordings obtained during a visual task reveal that the correlation between neural activity and behavioural choice also increases along the hierarchy. Our study provides a foundation for understanding coding and signal propagation across hierarchically organized cortical and thalamic visual areas.
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- 2021
6. TRIM18 is a critical regulator of viral myocarditis and organ inflammation
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Mingli Fang, Ao Zhang, Yong Du, Wenting Lu, Junying Wang, Laurie J. Minze, Timothy C. Cox, Xian Chang Li, Junji Xing, and Zhiqiang Zhang
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Inflammation ,Endocrinology, Diabetes and Metabolism ,Ubiquitin-Protein Ligases ,Biochemistry (medical) ,Clinical Biochemistry ,Cell Biology ,General Medicine ,Antiviral Agents ,Immunity, Innate ,Protein Phosphatase 2C ,Mice ,Myocarditis ,Virus Diseases ,Animals ,Humans ,RNA ,Pharmacology (medical) ,Encephalitis, Herpes Simplex ,Molecular Biology - Abstract
Background Infections by viruses including severe acute respiratory syndrome coronavirus 2 could cause organ inflammations such as myocarditis, pneumonia and encephalitis. Innate immunity to viral nucleic acids mediates antiviral immunity as well as inflammatory organ injury. However, the innate immune mechanisms that control viral induced organ inflammations are unclear. Methods To understand the role of the E3 ligase TRIM18 in controlling viral myocarditis and organ inflammation, wild-type and Trim18 knockout mice were infected with coxsackievirus B3 for inducing viral myocarditis, influenza A virus PR8 strain and human adenovirus for inducing viral pneumonia, and herpes simplex virus type I for inducing herpes simplex encephalitis. Mice survivals were monitored, and heart, lung and brain were harvested for histology and immunohistochemistry analysis. Real-time PCR, co-immunoprecipitation, immunoblot, enzyme-linked immunosorbent assay, luciferase assay, flow cytometry, over-expression and knockdown techniques were used to understand the molecular mechanisms of TRIM18 in regulating type I interferon (IFN) production after virus infection in this study. Results We find that knockdown or deletion of TRIM18 in human or mouse macrophages enhances production of type I IFN in response to double strand (ds) RNA and dsDNA or RNA and DNA virus infection. Importantly, deletion of TRIM18 protects mice from viral myocarditis, viral pneumonia, and herpes simplex encephalitis due to enhanced type I IFN production in vivo. Mechanistically, we show that TRIM18 recruits protein phosphatase 1A (PPM1A) to dephosphorylate TANK binding kinase 1 (TBK1), which inactivates TBK1 to block TBK1 from interacting with its upstream adaptors, mitochondrial antiviral signaling (MAVS) and stimulator of interferon genes (STING), thereby dampening antiviral signaling during viral infections. Moreover, TRIM18 stabilizes PPM1A by inducing K63-linked ubiquitination of PPM1A. Conclusions Our results indicate that TRIM18 serves as a negative regulator of viral myocarditis, lung inflammation and brain damage by downregulating innate immune activation induced by both RNA and DNA viruses. Our data reveal that TRIM18 is a critical regulator of innate immunity in viral induced diseases, thereby identifying a potential therapeutic target for treatment.
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- 2022
7. A distant global control region is essential for normal expression of anterior HOXA genes during mouse and human craniofacial development
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Andrea Wilderman, Eva D’haene, Machteld Baetens, Tara N. Yankee, Emma Wentworth Winchester, Nicole Glidden, Ellen Roets, Jo Van Dorpe, Sarah Vergult, Timothy C. Cox, and Justin Cotney
- Abstract
Defects in embryonic patterning resulting in craniofacial abnormalities account for approximately 1/3 of birth defects. The regulatory programs that build and shape the face require precisely controlled spatiotemporal gene expression, achieved through tissue-specific enhancers. Large regions with coactivation of enhancer elements and co-regulation of multiple genes, referred to as superenhancers, are important in determining cell identity and perturbation could result in developmental defects. Building upon a previously published epigenomic atlas of human embryonic craniofacial tissue in which we identified over 75,000 putative embryonic craniofacial enhancer regions, we have identified 531 superenhancer regions unique to embryonic craniofacial tissue, including 37 which fall in completely noncoding regions. To demonstrate the utility of this data for the understanding of craniofacial development and the etiology of craniofacial abnormalities, we focused on a craniofacial-specific superenhancer in a ∼600kb noncoding region located between NPVF and NFE2L3. This region harbors over 100 individual putative craniofacial enhancer segments and 7 in vivo validated craniofacial enhancers from primary craniofacial tissue as well as strong enhancer activation signatures in a culture model of cranial neural crest cell (CNCC) development. However, none of the directly adjacent genes have been implicated in neural crest specification, craniofacial development, or abnormalities. To identify potential regulatory targets of this superenhancer region, we characterized three-dimensional chromatin structure of this region in CNCCs and mouse embryonic craniofacial tissues using multiple techniques (4C-Seq, HiC). We identified long range interactions that exclude most intervening genes and specifically target the anterior portion of the HOXA gene cluster located 1.2 to 1.8 Mb away. We demonstrate the specificity of the enhancer region for regulation of anterior HOXA genes through CRISPR/Cas9 editing of human embryonic stem cells. Mice homozygous for deletion of the superenhancer confirm the specificity of the enhancer region and demonstrate that the region is essential for viability. At fetal stages homozygotes develop at the same rate as heterozygous and wild type littermates but die at P0-P1 and have high penetrance of orofacial clefts that phenocopy previously described Hoxa2-/- mice. Moreover, we identified a de novo deletion partially overlapping the superenhancer in a human fetus with severe craniofacial abnormalities. This evidence suggests we have identified a critical noncoding locus control region that specifically regulates anterior HOXA genes and whose deletion is likely pathogenic in human patients.
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- 2022
8. Decision letter: EZ Clear for simple, rapid, and robust mouse whole organ clearing
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Timothy C Cox
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- 2022
9. Interferon receptor gene dosage determines diverse hallmarks of Down syndrome
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Katherine A. Waugh, Ross Minter, Jessica Baxter, Congwu Chi, Kathryn D. Tuttle, Neetha P. Eduthan, Matthew D. Galbraith, Kohl T. Kinning, Zdenek Andrysik, Paula Araya, Hannah Dougherty, Lauren N. Dunn, Michael Ludwig, Kyndal A. Schade, Dayna Tracy, Keith P. Smith, Ross E. Granrath, Nicolas Busquet, Santosh Khanal, Ryan D. Anderson, Liza L. Cox, Belinda Enriquez Estrada, Angela L. Rachubinski, Hannah R. Lyford, Eleanor C. Britton, David J. Orlicky, Jennifer L. Matsuda, Kunhua Song, Timothy C. Cox, Kelly D. Sullivan, and Joaquin M. Espinosa
- Abstract
Trisomy 21 causes Down syndrome, a condition characterized by cognitive impairments, immune dysregulation, and atypical morphogenesis. Using whole blood transcriptome analysis, we demonstrate that specific overexpression of four interferon receptors encoded on chromosome 21 associates with chronic interferon hyperactivity and systemic inflammation in Down syndrome. To define the contribution of interferon receptor overexpression to Down syndrome phenotypes, we used genome editing to correct interferon receptor gene dosage in mice carrying triplication of a large genomic region orthologous to human chromosome 21. Normalization of interferon receptor copy number attenuated lethal antiviral responses, prevented heart malformations, decreased developmental delays, improved cognition and normalized craniofacial anomalies. Therefore, interferon receptor gene dosage determines major hallmarks of Down syndrome, indicating that trisomy 21 elicits an interferonopathy amenable to therapeutic intervention.One-Sentence SummaryCorrection of interferon receptor gene dosage rescues multiple key phenotypes in a mouse model of trisomy 21.
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- 2022
10. The Society for Craniofacial Genetics and Developmental Biology 42nd Annual Meeting
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Sally A. Moody, Paul A. Trainor, Jean Pierre Saint-Jeannet, Lisa A. Taneyhill, Timothy C. Cox, George T. Eisenhoffer, and David E. Clouthier
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Genetics ,2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,Graduate students ,Craniofacial abnormality ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,education ,medicine ,Craniofacial ,medicine.disease ,Patient advocacy ,Genetics (clinical) - Abstract
The mission of the Society for Craniofacial Genetics and Developmental Biology (SCGDB) is to promote education, research, and communication about normal and abnormal development of the tissues and organs of the head. The SCGDB welcomes as members undergraduate students, graduate students, post doctoral researchers, clinicians, orthodontists, scientists, and academicians who share an interest in craniofacial biology. Each year our members come together to share their novel findings, build upon, and challenge current knowledge of craniofacial biology. © 2016 Wiley Periodicals, Inc.
- Published
- 2020
11. Loss of Function TGFBR2 Variant as a Contributing Factor in Generalized Pustular Psoriasis and Adult-Onset Immunodeficiency
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Piranit Kantaputra, Teerada Daroontum, Mati Chuamanochan, Suteeraporn Chaowattanapanit, Worrachet Intachai, Bjorn Olsen, Thanapat Sastraruji, Sissades Tongsima, Chumpol Ngamphiw, Jatupol Kampuansai, Timothy C. Cox, and Salin Kiratikanon
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Genetics ,adult-onset immunodeficiency syndrome ,anti-interferon-γ autoantibody ,TGFBR2 mutation ,generalized pustular psoriasis ,predisposing risk factor ,pustular skin reaction ,Genetics (clinical) - Abstract
Background: Generalized pustular psoriasis (GPP; MIM 614204) is a rare multisystemic autoinflammatory disease, characterized by episodes of acute generalized erythema and scaling developed with the spread of numerous sterile pustules. Adult-onset immunodeficiency syndrome (AOID) with anti-interferon-γ autoantibodies is an immunodeficiency disorder associated with disruptive IFN-γ signaling. Methods: Clinical examination and whole exome sequencing (WES) were performed on 32 patients with pustular psoriasis phenotypes and 21 patients with AOID with pustular skin reaction. Histopathological and immunohistochemical studies were performed. Results: WES identified four Thai patients presenting with similar pustular phenotypes—two with a diagnosis of GPP and the other two with AOID—who were found to carry the same rare TGFBR2 frameshift mutation c.458del; p.Lys153SerfsTer35, which is predicted to result in a marked loss of functional TGFBR2 protein. The immunohistochemical studied showed overexpression of IL1B, IL6, IL17, IL23, IFNG, and KRT17, a hallmark of psoriatic skin lesions. Abnormal TGFB1 expression was observed in the pustular skin lesion of an AOID patient, suggesting disruption to TGFβ signaling is associated with the hyperproliferation of the psoriatic epidermis. Conclusions: This study implicates disruptive TGFBR2-mediated signaling, via a shared truncating variant, c.458del; p.Lys153SerfsTer35, as a “predisposing risk factor” for GPP and AOID.
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- 2022
12. Auriculocondylar syndrome 2 results from the dominant-negative action of PLCB4 variants
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Stanley M. Kanai, Caleb Heffner, Timothy C. Cox, Michael L. Cunningham, Francisco A. Perez, Aaron M. Bauer, Philip Reigan, Cristan Carter, Stephen A. Murray, and David E. Clouthier
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Mice ,Phenotype ,Immunology and Microbiology (miscellaneous) ,Neural Crest ,Neuroscience (miscellaneous) ,Phospholipase C beta ,Medicine (miscellaneous) ,Animals ,Humans ,Ear ,Ear Diseases ,General Biochemistry, Genetics and Molecular Biology - Abstract
Auriculocondylar syndrome 2 (ARCND2) is a rare autosomal dominant craniofacial malformation syndrome linked to multiple genetic variants in the coding sequence of phospholipase C β4 (PLCB4). PLCB4 is a direct signaling effector of the endothelin receptor type A (EDNRA)-Gq/11 pathway, which establishes the identity of neural crest cells (NCCs) that form lower jaw and middle ear structures. However, the functional consequences of PLCB4 variants on EDNRA signaling is not known. Here, we show, using multiple signaling reporter assays, that known PLCB4 variants resulting from missense mutations exert a dominant-negative interference over EDNRA signaling. In addition, using CRISPR/Cas9, we find that F0 mouse embryos modeling one PLCB4 variant have facial defects recapitulating those observed in hypomorphic Ednra mouse models, including a bone that we identify as an atavistic change in the posterior palate/oral cavity. Remarkably, we have identified a similar osseous phenotype in a child with ARCND2. Our results identify the disease mechanism of ARCND2, demonstrate that the PLCB4 variants cause craniofacial differences and illustrate how minor changes in signaling within NCCs may have driven evolutionary changes in jaw structure and function. This article has an associated First Person interview with the first author of the paper.
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- 2021
13. Response to Hamosh et al
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John M. Graham, Joseph T. Shieh, Alan F. Rope, Philip F Giampietro, Lynne M. Bird, Roberta A Pagon, John C. Carey, Katta M. Girisha, Cathy A. Stevens, David D. Weaver, Margaret P. Adam, William B. Dobyns, Bryan D. Hall, Elaine H. Zackai, Chad R. Haldeman-Englert, Anne C. Tsai, A. Micheil Innes, Marc S. Williams, Ian A. Glass, David A. Stevenson, Kenjiro Kosaki, Beth A. Kozel, Jennifer M. Kalish, Michael J. Bamshad, John J. Mulvihill, Robin D. Clark, Anne Slavotinek, Kim M. Keppler-Noreuil, Anita E. Beck, Małgorzata J.M. Nowaczyk, Cynthia J. Curry, Fowzan S. Alkuraya, Ghayda M. Mirzaa, Timothy C. Cox, Anne Amemiya, Karen W. Gripp, Wen-Hann Tan, Andrew K. Sobering, Yuri A. Zarate, Mary Beth Dinulos, Laurie H. Seaver, James T. Bennett, Leslie G. Biesecker, Kyle Retterer, Tiong Yang Tan, Brian H.Y. Chung, and Pedro A. Sanchez-Lara
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Genetics ,Biology ,Letter to the Editor ,Genetics (clinical) - Published
- 2021
14. A dyadic approach to the delineation of diagnostic entities in clinical genomics
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Wen-Hann Tan, Małgorzata J.M. Nowaczyk, Joseph T. Shieh, Anne Slavotinek, John M. Graham, Lynne M. Bird, David D. Weaver, Laurie H. Seaver, Anne Amemiya, Ghayda Mirzaa, Beth A. Kozel, Jennifer M. Kalish, John C. Carey, Anita E. Beck, Margaret P. Adam, Bryan D. Hall, Philip F Giampietro, Kim M. Keppler-Noreuil, David A. Stevenson, Karen W. Gripp, Robin D. Clark, Mary Beth Dinulos, William B. Dobyns, Pedro A. Sanchez-Lara, Roberta A Pagon, Andrew K. Sobering, Michael J. Bamshad, Fowzan S. Alkuraya, Tiong Yang Tan, Brian H.Y. Chung, Alan F. Rope, Elaine H. Zackai, Marc S. Williams, John J. Mulvihill, James T. Bennett, Leslie G. Biesecker, Kyle Retterer, Yuri A. Zarate, Timothy C. Cox, Chad R. Haldeman-Englert, Anne C. Tsai, Ian A. Glass, Cynthia J. Curry, Kenjiro Kosaki, A. Micheil Innes, Katta M. Girisha, and Cathy A. Stevens
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0301 basic medicine ,Cystic Fibrosis ,Genotype ,Computer science ,Cystic Fibrosis Transmembrane Conductance Regulator ,Disease ,Computational biology ,030105 genetics & heredity ,Medical and Health Sciences ,03 medical and health sciences ,symbols.namesake ,Rare Diseases ,Genetics ,medicine ,Humans ,Mendelian disorders ,Letter to the Editor ,Genetics (clinical) ,Simple (philosophy) ,Genetics & Heredity ,Clinical genomics ,Extramural ,Genetic disorder ,Genetic Diseases, Inborn ,Genomics ,Biological Sciences ,medicine.disease ,Inborn ,030104 developmental biology ,Phenotype ,Genetic Diseases ,Perspective ,Mutation ,Mendelian inheritance ,symbols - Abstract
The delineation of disease entities is complex, yet recent advances in the molecular characterization of diseases provide opportunities to designate diseases in a biologically valid manner. Here, we have formalized an approach to the delineation of Mendelian genetic disorders that encompasses two distinct but inter-related concepts: (1) the gene that is mutated and (2) the phenotypic descriptor, preferably a recognizably distinct phenotype. We assert that only by a combinatorial or dyadic approach taking both of these attributes into account can a unitary, distinct genetic disorder be designated. We propose that all Mendelian disorders should be designated as “GENE-related phenotype descriptor” (e.g., “CFTR-related cystic fibrosis”). This approach to delineating and naming disorders reconciles the complexity of gene-to-phenotype relationships in a simple and clear manner yet communicates the complexity and nuance of these relationships.
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- 2021
15. Author response: Rapamycin rejuvenates oral health in aging mice
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Jonathan Y. An, Timothy C. Cox, Andrew Ouellette, Title Mekvanich, Jeffrey S. McLean, Matt Kaeberlein, Alex Kang, Kristopher A. Kerns, So-Il Park, H Douglas Morris, Laura Robinson, and Catherine C. Kaczorowski
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business.industry ,Medicine ,Physiology ,Oral health ,business - Published
- 2020
16. Survey of spiking in the mouse visual system reveals functional hierarchy
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Joshua H, Siegle, Xiaoxuan, Jia, Séverine, Durand, Sam, Gale, Corbett, Bennett, Nile, Graddis, Greggory, Heller, Tamina K, Ramirez, Hannah, Choi, Jennifer A, Luviano, Peter A, Groblewski, Ruweida, Ahmed, Anton, Arkhipov, Amy, Bernard, Yazan N, Billeh, Dillan, Brown, Michael A, Buice, Nicolas, Cain, Shiella, Caldejon, Linzy, Casal, Andrew, Cho, Maggie, Chvilicek, Timothy C, Cox, Kael, Dai, Daniel J, Denman, Saskia E J, de Vries, Roald, Dietzman, Luke, Esposito, Colin, Farrell, David, Feng, John, Galbraith, Marina, Garrett, Emily C, Gelfand, Nicole, Hancock, Julie A, Harris, Robert, Howard, Brian, Hu, Ross, Hytnen, Ramakrishnan, Iyer, Erika, Jessett, Katelyn, Johnson, India, Kato, Justin, Kiggins, Sophie, Lambert, Jerome, Lecoq, Peter, Ledochowitsch, Jung Hoon, Lee, Arielle, Leon, Yang, Li, Elizabeth, Liang, Fuhui, Long, Kyla, Mace, Jose, Melchior, Daniel, Millman, Tyler, Mollenkopf, Chelsea, Nayan, Lydia, Ng, Kiet, Ngo, Thuyahn, Nguyen, Philip R, Nicovich, Kat, North, Gabriel Koch, Ocker, Doug, Ollerenshaw, Michael, Oliver, Marius, Pachitariu, Jed, Perkins, Melissa, Reding, David, Reid, Miranda, Robertson, Kara, Ronellenfitch, Sam, Seid, Cliff, Slaughterbeck, Michelle, Stoecklin, David, Sullivan, Ben, Sutton, Jackie, Swapp, Carol, Thompson, Kristen, Turner, Wayne, Wakeman, Jennifer D, Whitesell, Derric, Williams, Ali, Williford, Rob, Young, Hongkui, Zeng, Sarah, Naylor, John W, Phillips, R Clay, Reid, Stefan, Mihalas, Shawn R, Olsen, and Christof, Koch
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Electrophysiology ,Male ,Mice, Inbred C57BL ,Mice ,Thalamus ,Action Potentials ,Animals ,Datasets as Topic ,Photic Stimulation ,Visual Cortex - Abstract
The anatomy of the mammalian visual system, from the retina to the neocortex, is organized hierarchically
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- 2019
17. Loss of PiT-2 results in abnormal bone development and decreased bone mineral density and length in mice
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Suhaib Borgeia, Shunsuke Yamada, Timothy C. Cox, Mary C. Wallingford, and Cecilia M. Giachelli
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Male ,0301 basic medicine ,medicine.medical_specialty ,Biophysics ,Biochemistry ,Article ,Bone and Bones ,Bone resorption ,Bone remodeling ,Mice ,03 medical and health sciences ,chemistry.chemical_compound ,Bone Density ,Internal medicine ,Bone cell ,medicine ,Animals ,Femur ,Tibia ,Molecular Biology ,Mice, Knockout ,Bone mineral ,Bone Development ,Sodium-Phosphate Cotransporter Proteins, Type III ,Organ Size ,Cell Biology ,Phosphate ,Mice, Inbred C57BL ,030104 developmental biology ,Endocrinology ,chemistry ,Knockout mouse ,Bone Diseases - Abstract
Normal bone mineralization requires phosphate oversaturation in bone matrix vesicles, as well as normal regulation of phosphate metabolism via the interplay among bone, intestine, and kidney. In turn, derangement of phosphate metabolism greatly affects bone function and structure. The type III sodium-dependent phosphate transporters, PiT-1 and PiT-2, are believed to be important in tissue phosphate metabolism and physiological bone formation, but their requirement and molecular roles in bone remain poorly investigated. In order to decipher the role of PiT-2 in bone, we examined normal bone development, growth, and mineralization in global PiT-2 homozygous knockout mice. PiT-2 deficiency resulted in reduced vertebral column, femur, and tibia length as well as mandibular dimensions. Micro-computed tomography analysis revealed that bone mineral density in the mandible, femur, and tibia were decreased, indicating that maintenance of bone function and structure is impaired in both craniofacial and long bones of PiT-2 deficient mice. Both cortical and trabecular thickness and mineral density were reduced in PiT-2 homozygous knockout mice compared with wild-type mice. These results suggest that PiT-2 is involved in normal bone development and growth and plays roles in cortical and trabecular bone metabolism feasibly by regulating local phosphate transport and mineralization processes in the bone. Further studies that evaluate bone cell-specific loss of PiT-2 are now warranted and may yield insight into complex mechanisms of bone development and growth, leading to identification of new therapeutic options for patients with bone diseases.
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- 2018
18. Associations between laterality of orofacial clefts and medical and academic outcomes
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Timothy C. Cox, Emily R. Gallagher, Brent R. Collett, Babette Siebold, Verena Aziz, and Michael L. Cunningham
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Male ,Pediatrics ,medicine.medical_specialty ,Cleft Lip ,MEDLINE ,Comorbidity ,Logistic regression ,03 medical and health sciences ,0302 clinical medicine ,030225 pediatrics ,Outcome Assessment, Health Care ,Odds Ratio ,Genetics ,medicine ,Humans ,Medical history ,Craniofacial ,Genetics (clinical) ,Medicaid ,business.industry ,Medical record ,Retrospective cohort study ,Syndrome ,030206 dentistry ,United States ,Cleft Palate ,Socioeconomic Factors ,Laterality ,Etiology ,Female ,business - Abstract
Patients with oral clefts have an increased risk of other malformations, syndromes, and lower academic performance in school. Few studies have investigated if laterality of clefts is associated with medical and academic outcomes. Oral clefts have nonrandom laterality, with left-sided clefts occurring approximately twice as often as right-sided clefts. Using a retrospective study design, we examined potential associations of cleft attributes and outcomes in patients with cleft lip with or without cleft palate (CL/P) born in 2003-2010 who were treated at the Seattle Children's Craniofacial Center. The following variables were extracted from medical records: cleft type, medical history, maternal hyperglycemia, other malformations, and the need for academic support at school. We used logistic regression to examine risk of associations with outcomes of interest. Relative to patients with left-sided clefts, patients with bilateral CL/P were more likely to have a syndrome. Patients with nonsyndromic right-sided CL/P had a higher risk (OR and 95%CI: 3.5, 1.3-9.5, and 5.5, 1.9-16.0, respectively) of having other malformations and requiring academic support at school, when compared to patients with left-sided CL/P. Understanding the etiology of oral clefts is complicated, in part because both genetic and environmental factors contribute to the risk of developing a cleft. However, the different outcomes associated with cleft laterality suggest that right-sided clefts may have a distinct etiology. Using laterality to study cleft subgroups may advance our understanding of the etiology of this common birth defect.
- Published
- 2017
19. Disrupted IRF6-NME1/2 Complexes as a Cause of Cleft Lip/Palate
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Parada-Sanchez Mt, Jennifer Standley, Liza L Cox, Jeffrey C. Murray, Undurty Ss, Timothy C. Cox, and Chu Ey
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0301 basic medicine ,Cleft Lip ,Tissue Adhesions ,Chick Embryo ,Bioinformatics ,medicine.disease_cause ,Polymerase Chain Reaction ,03 medical and health sciences ,0302 clinical medicine ,Animals ,Humans ,Immunoprecipitation ,Medicine ,Phosphorylation ,General Dentistry ,Mutation ,Cleft lip palate ,business.industry ,NM23 Nucleoside Diphosphate Kinases ,Genetic Variation ,Research Reports ,Cleft Palate ,030104 developmental biology ,030220 oncology & carcinogenesis ,Interferon Regulatory Factors ,IRF6 ,business ,Transcription Factors ,Interferon regulatory factors - Abstract
Mutations and common polymorphisms in interferon regulatory factor 6 ( IRF6) are associated with both syndromic and nonsyndromic forms of cleft lip/palate (CLP). To date, much of the focus on this transcription factor has been on identifying its direct targets and the gene regulatory network in which it operates. Notably, however, IRF6 is found predominantly in the cytoplasm, with its import into the nucleus tightly regulated like other members of the IRF family. To provide further insight into the role of IRF6 in the pathogenesis of CLP, we sought to identify direct IRF6 protein interactors using a combination of yeast 2-hybrid screens and co-immunoprecipitation assays. Using this approach, we identified NME1 and NME2, well-known regulators of Rho-type GTPases, E-cadherin endocytosis, and epithelial junctional remodeling, as bona fide IRF6 partner proteins. The NME proteins co-localize with IRF6 in the cytoplasm of primary palatal epithelial cells in vivo, and their interaction with IRF6 is significantly enhanced by phosphorylation of key serine residues in the IRF6 C-terminus. Furthermore, CLP associated IRF6 missense mutations disrupt the ability of IRF6 to bind the NME proteins and result in elevated activation of Rac1 and RhoA, compared to wild-type IRF6, when ectopically expressed in 293T epithelial cells. Significantly, we also report the identification of 2 unique missense mutations in the NME proteins in patients with CLP (NME1 R18Q in an IRF6 and GRHL3 mutation-negative patient with van der Woude syndrome and NME2 G71V in a patient with nonsyndromic CLP). Both variants disrupted the ability of the respective proteins to interact with IRF6. The data presented suggest an important role for cytoplasmic IRF6 in regulating the availability or localization of the NME1/2 complex and thus the dynamic behavior of epithelia during lip/palate development.
- Published
- 2017
20. Rapamycin treatment attenuates age-associated periodontitis in mice
- Author
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Matt Kaeberlein, Alex Kang, Jonathan Y. An, Anthony Liu, Surapat Mekvanich, Timothy C. Cox, Ellen Quarles, Richard A. Miller, Peter S. Rabinovitch, and Danielle Santos
- Subjects
0301 basic medicine ,Periodontitis ,Senescence ,Aging ,business.industry ,Inflammation ,Disease ,medicine.disease ,Systemic inflammation ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Immune system ,Immunology ,Medicine ,Original Article ,Microbiome ,Geriatrics and Gerontology ,medicine.symptom ,business ,030217 neurology & neurosurgery ,Dental alveolus - Abstract
Interventions that target biological mechanisms of aging have great potential to enhance quality of life by delaying morbidity and mortality. The FDA-approved drug rapamycin is a compelling candidate for such an intervention. In a previous study, it was reported that 3 months of rapamycin treatment is sufficient to increase life expectancy and remodel the gut microbiome in aged mice. Transient treatment with rapamycin or a rapamycin derivative has also been shown to delay immune stem cell senescence and rejuvenate immune function in aged mice and elderly people. Periodontal disease is an important age-related disease involving altered immune function, pathological changes to the oral microbiome, and systemic inflammation. Periodontal disease is defined clinically by loss of alveolar bone and by connective tissue degeneration. Here, we describe significant alveolar bone loss during aging in two different mouse strain backgrounds and report that rapamycin treatment is sufficient to reverse age-associated periodontal disease in mice. Partial restoration of youthful levels of alveolar bone is observed in 22-month-old rapamycin-treated mice as rapidly as 8 weeks after initiation of treatment. To the best of our knowledge, this represents the first intervention shown to substantially prevent or reverse age-associated alveolar bone loss. These findings suggest the possibility that inhibition of mTOR with rapamycin or other pharmacological agents may be useful to treat a clinically relevant condition for which there is currently no effective treatment.
- Published
- 2017
21. Isl1 Controls Patterning and Mineralization of Enamel in the Continuously Renewing Mouse Incisor
- Author
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Bo Meng, Bernhard Ganss, Michaela Prochazkova, Timothy Wen, Adrien Naveau, Timothy C. Cox, McGarrett T Sutherland, Andrew H. Jheon, Kyle B. Jones, Pauline Marangoni, Bin Zhang, and Ophir D. Klein
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Enamel paint ,Ectopic enamel ,Chemistry ,Endocrinology, Diabetes and Metabolism ,Amelogenesis ,Bone morphogenetic protein ,Fibroblast growth factor ,Cell biology ,stomatognathic diseases ,03 medical and health sciences ,030104 developmental biology ,Endocrinology ,stomatognathic system ,Internal medicine ,visual_art ,medicine ,visual_art.visual_art_medium ,Orthopedics and Sports Medicine ,Stem cell ,Ameloblast ,Reduced enamel epithelium - Abstract
Rodents are characterized by continuously renewing incisors whose growth is fueled by epithelial and mesenchymal stem cells housed in the proximal compartments of the tooth. The epithelial stem cells reside in structures known as the labial (toward the lip) and lingual (toward the tongue) cervical loops (laCL and liCL, respectively). An important feature of the rodent incisor is that enamel, the outer, highly mineralized layer, is asymmetrically distributed, because it is normally generated by the laCL but not the liCL. Here, we show that epithelial-specific deletion of the transcription factor Islet1 (Isl1) is sufficient to drive formation of ectopic enamel by the liCL stem cells, and also that it leads to production of altered enamel on the labial surface. Molecular analyses of developing and adult incisors revealed that epithelial deletion of Isl1 affected multiple, major pathways: Bmp (bone morphogenetic protein), Hh (hedgehog), Fgf (fibroblast growth factor), and Notch signaling were upregulated and associated with liCL-generated ectopic enamel; on the labial side, upregulation of Bmp and Fgf signaling, and downregulation of Shh were associated with premature enamel formation. Transcriptome profiling studies identified a suite of differentially regulated genes in developing Isl1 mutant incisors. Our studies demonstrate that ISL1 plays a central role in proper patterning of stem cell-derived enamel in the incisor and indicate that this factor is an important upstream regulator of signaling pathways during tooth development and renewal. © 2017 American Society for Bone and Mineral Research.
- Published
- 2017
22. Intra‐ and Intersexual swim bladder dimorphisms in the plainfin midshipman fish ( Porichthys notatus ): Implications of swim bladder proximity to the inner ear for sound pressure detection
- Author
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Richard R. Fay, Ryan D. Anderson, Elizabeth A. Whitchurch, Paul M. Forlano, Timothy C. Cox, Darlene R. Ketten, Joseph A. Sisneros, and Robert A. Mohr
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Male ,030110 physiology ,0106 biological sciences ,0301 basic medicine ,media_common.quotation_subject ,Midshipman fish ,Lagena ,010603 evolutionary biology ,01 natural sciences ,Courtship ,03 medical and health sciences ,Imaging, Three-Dimensional ,Utricle ,Swim bladder ,Pressure ,medicine ,Seasonal breeder ,Animals ,Inner ear ,media_common ,Sex Characteristics ,Air Sacs ,biology ,Anatomy ,Batrachoidiformes ,biology.organism_classification ,Phenotype ,Sound ,medicine.anatomical_structure ,Porichthys notatus ,Ear, Inner ,Female ,Animal Science and Zoology ,Tomography, X-Ray Computed ,Developmental Biology - Abstract
The plainfin midshipman fish, Porichthys notatus, is a nocturnal marine teleost that uses social acoustic signals for communication during the breeding season. Nesting type I males produce multiharmonic advertisement calls by contracting their swim bladder sonic muscles to attract females for courtship and spawning while subsequently attracting cuckholding type II males. Here, we report intra- and intersexual dimorphisms of the swim bladder in a vocal teleost fish and detail the swim bladder dimorphisms in the three sexual phenotypes (females, type I and II males) of plainfin midshipman fish. Micro-computerized tomography revealed that females and type II males have prominent, horn-like rostral swim bladder extensions that project toward the inner ear end organs (saccule, lagena, and utricle). The rostral swim bladder extensions were longer, and the distance between these swim bladder extensions and each inner-ear end organ type was significantly shorter in both females and type II males compared to that in type I males. Our results revealed that the normalized swim bladder length of females and type II males was longer than that in type I males while there was no difference in normalized swim bladder width among the three sexual phenotypes. We predict that these intrasexual and intersexual differences in swim bladder morphology among midshipman sexual phenotypes will afford greater sound pressure sensitivity and higher frequency detection in females and type II males and facilitate the detection and localization of conspecifics in shallow water environments, like those in which midshipman breed and nest.
- Published
- 2017
23. A translational cellular model to study the impact of high-frequency oscillatory ventilation on human epithelial cell function
- Author
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Timothy C. Cox, Thomas H. Shaffer, Yan Zhu, Beatriz E. de Jongh, and Anja Mowes
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Physiology ,medicine.medical_treatment ,High-Frequency Ventilation ,Hyperoxia ,Lung injury ,03 medical and health sciences ,0302 clinical medicine ,030225 pediatrics ,Physiology (medical) ,medicine ,Humans ,Cells, Cultured ,Oscillatory ventilation ,business.industry ,Respiration ,High-frequency ventilation ,Epithelial Cells ,Lung Injury ,respiratory system ,Epithelium ,respiratory tract diseases ,Oxygen ,medicine.anatomical_structure ,030228 respiratory system ,Anesthesia ,Innovative Methodology ,Biophysics ,Cellular model ,business ,Function (biology) ,High frequency oscillatory ventilation - Abstract
High-frequency oscillatory ventilation (HFOV) has been proposed as gentle ventilation strategy to prevent lung injury in the preterm infant. High-frequency jet ventilation leads to dimensional and mechanical airway deformation in animal airway models, which is consistent with translational studies demonstrating the impact of oxygen and biophysical stresses on normal airway cellular function. There is an overall paucity of clinical and cellular data on the impact of HFOV on the conducting airway. We developed an innovative method to test the impact of the clinical HFO Ventilator (SensorMedics 3100A) on human epithelial cell function. In this translational model, we were able to study the differential effects of biophysical stress due to HFOV independently and in combination with hyperoxia on a direct cellular level of the conducting airway system. Additionally, we could demonstrate that hyperoxia and pressure by HFOV independently resulted in significant cell dysfunction and inflammation, while the combination of HFOV and hyperoxia had a synergistic effect, resulting in greater cell death.NEW & NOTEWORTHY Traditionally, large-animal models are used to analyze the impact of clinical ventilators on lung cellular function. In our dual-chamber model, we interface high-frequency oscillatory ventilation (HFOV) directly with airway cells to study the effects of HFOV independently and combined with hyperoxia. Therefore, it is possible to study the preclinical impact of interventional factors without the high cost of animal models, thus reducing staff, time, as well as animal sparing.
- Published
- 2017
24. Front Cover, Volume 40, Issue 10
- Author
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Timothy C. Cox, Andrew C. Lidral, Jason C. McCoy, Huan Liu, Liza L. Cox, Ying Zhu, Ryan D. Anderson, Lina M. Moreno Uribe, Deepti Anand, Mei Deng, Chika T. Richter, Nichole L. Nidey, Jennifer M. Standley, Elizabeth E. Blue, Jessica X. Chong, Joshua D. Smith, Edwin P. Kirk, Hanka Venselaar, Katy N. Krahn, Hans Bokhoven, Huiqing Zhou, Robert A. Cornell, Ian A. Glass, Michael J. Bamshad, Deborah A. Nickerson, Jeffrey C. Murray, Salil A. Lachke, Thomas B. Thompson, Michael F. Buckley, and Tony Roscioli
- Subjects
Genetics ,Genetics (clinical) - Published
- 2019
25. Transcranial Doppler and Magnetic Resonance in Tanzanian Children With Sickle Cell Disease
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Dawn E. Saunders, Timothy C. Cox, Emmanuel Munubhi, Fenella J. Kirkham, Deogratias Soka, Joyce Komba, Mechris Mango, Sharon E. Cox, Angela Darekar, Edward Kija, Deogratias A. Nkya, Charles R. Newton, and Simon Barker
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Male ,Ultrasonography, Doppler, Transcranial ,Original Contributions ,Infarction ,Disease ,Tanzania ,Magnetic resonance angiography ,Hemoglobins ,0302 clinical medicine ,Risk Factors ,Medicine ,magnetic resonance imaging ,Child ,Stroke ,medicine.diagnostic_test ,Cerebral Infarction ,3. Good health ,030220 oncology & carcinogenesis ,Cerebrovascular Circulation ,Cardiology ,cardiovascular system ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,Female ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,medicine.medical_specialty ,Weakness ,Adolescent ,brain ,Clinical Sciences ,infarction ,Pain ,Anemia, Sickle Cell ,03 medical and health sciences ,Internal medicine ,Humans ,cardiovascular diseases ,Advanced and Specialized Nursing ,business.industry ,magnetic resonance angiography ,Magnetic resonance imaging ,hemoglobin ,medicine.disease ,Transcranial Doppler ,Neurology (clinical) ,Hemoglobin ,business ,030217 neurology & neurosurgery - Abstract
Supplemental Digital Content is available in the text., Background and Purpose— We determined prevalences of neurological complications, vascular abnormality, and infarction in Tanzanian children with sickle cell disease. Methods— Children with sickle cell disease were consecutively enrolled for transcranial Doppler; those with slightly elevated (>150 cm/s), low (150 cm/s was associated with frequent painful crises and low hemoglobin level. Absent/low CBFv was associated with low hemoglobin level and history of unilateral weakness. In 49 out of 67 children with low/absent/elevated transcranial Doppler undergoing magnetic resonance imaging, 43% had infarction, whereas 24 out of 48 (50%) magnetic resonance angiographies were abnormal. One had hemorrhagic infarction; none had microbleeds. Posterior circulation infarcts occurred in 14%. Of 11 children with previous seizure undergoing magnetic resonance imaging, 10 (91%) had infarction (5 silent) compared with 11 out of 38 (29%) of the remainder (P=0.003). Of 7 children with clinical stroke, 2 had recurrent stroke and 3 died; 4 out of 5 had absent CBFv. Of 193 without stroke, 1 died and 1 had a stroke; both had absent CBFv. Conclusions— In one-third of Tanzanian children with sickle cell disease, CBFv is outside the normal range, associated with frequent painful crises and low hemoglobin level, but not hemolysis. Half have abnormal magnetic resonance angiography. African children with sickle cell disease should be evaluated with transcranial Doppler; those with low/absent/elevated CBFv should undergo magnetic resonance imaging/magnetic resonance angiography.
- Published
- 2019
26. Altering calcium and phosphorus levels in utero affects adult mouse mandibular morphology
- Author
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Hanan Ismail, Timothy C. Cox, Ricardo Vargas, Mohamed G. Hassan, Clare Lee, Abbas R. Zaher, and Andrew H. Jheon
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Male ,medicine.medical_specialty ,Normal diet ,Offspring ,chemistry.chemical_element ,Orthodontics ,Mandible ,Calcium ,Biology ,Condyle ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Internal medicine ,medicine ,Weaning ,Animals ,030212 general & internal medicine ,Bone mineral ,Mandibular Condyle ,Phosphorus ,030206 dentistry ,X-Ray Microtomography ,Endocrinology ,Otorhinolaryngology ,chemistry ,In utero ,Surgery ,Female ,Oral Surgery - Abstract
OBJECTIVES The purpose of our study was to determine morphological changes and bone mineral density (BMD) differences in the adult mandible of offspring exposed to high calcium, low phosphorus diets in utero until weaning age. MATERIALS AND METHODS Time-mated FVB wild-type mice were fed normal or experimental diet during gestation and until weaning of offspring. Experimental diet contained 3-fold increase in calcium and 3-fold decrease in phosphorus compared to normal diet. Adult mandibles of offspring exposed to experimental diet were sacrificed and heads scanned using micro-computed tomography. Three-dimensional 3D geometric morphometric analysis GMA was utilized to detect morphological changes to the mandible including the condyle. RESULTS Experimental females showed the greatest morphological differences including shortened mandibular ramus width and height, shortened mandibular body length and height, a wider but shortened condylar neck and a wider condylar head in the lateral-medial direction. Experimental male mandibles trended towards increased mandibular body height and length, opposite the changes observed in experimental female mandibles, whereas condyles were similar to that observed in experimental females. Bone mineral density (BMD) was lowered in experimental females. CONCLUSION Increased calcium and decreased phosphorus levels led to a retrognathic mandible associated with lowered BMD in experimental females, whereas experimental showed partly opposite effects. Further studies are required to understand the mechanism underlying diet- and gender-specific differences in mandibular morphology.
- Published
- 2018
27. Mutations in GDF11 and the extracellular antagonist, Follistatin, as a likely cause of Mendelian forms of orofacial clefting in humans
- Author
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Andrew C. Lidral, Deborah A. Nickerson, Ryan D. Anderson, Chika T. Richter, Robert A. Cornell, Lina M. Moreno Uribe, Huiqing Zhou, Deepti Anand, Jessica X. Chong, Hans van Bokhoven, Elizabeth E. Blue, Edwin P. Kirk, Mei Deng, Joshua D. Smith, Nichole Nidey, Jason C. McCoy, Jennifer Standley, Huan Liu, Katy N. Krahn, Jeffrey C. Murray, Salil A. Lachke, Hanka Venselaar, Timothy C. Cox, Michael J. Bamshad, Tony Roscioli, Ying Zhu, Michael F. Buckley, Ian A. Glass, Liza L Cox, and Thomas B. Thompson
- Subjects
Models, Molecular ,Follistatin ,Protein Conformation ,Cleft Lip ,Biology ,Article ,Cell Line ,03 medical and health sciences ,symbols.namesake ,130 000 Cognitive Neurology & Memory ,Exome Sequencing ,Genetics ,Humans ,Genetic Predisposition to Disease ,Gene ,Furin ,Genetics (clinical) ,Exome sequencing ,Alleles ,Genetic Association Studies ,030304 developmental biology ,0303 health sciences ,Neurodevelopmental disorders Donders Center for Medical Neuroscience [Radboudumc 7] ,030305 genetics & heredity ,Computational Biology ,Genomics ,Phenotype ,Pedigree ,Growth Differentiation Factors ,Reconstructive and regenerative medicine Radboud Institute for Molecular Life Sciences [Radboudumc 10] ,Amino Acid Substitution ,GDF11 ,Knockout mouse ,Bone Morphogenetic Proteins ,Mutation ,biology.protein ,Mendelian inheritance ,symbols ,Molecular Developmental Biology ,Nanomedicine Radboud Institute for Molecular Life Sciences [Radboudumc 19] - Abstract
Contains fulltext : 208676.pdf (Publisher’s version ) (Open Access) Cleft lip with or without cleft palate (CL/P) is generally viewed as a complex trait with multiple genetic and environmental contributions. In 70% of cases, CL/P presents as an isolated feature and/or deemed nonsyndromic. In the remaining 30%, CL/P is associated with multisystem phenotypes or clinically recognizable syndromes, many with a monogenic basis. Here we report the identification, via exome sequencing, of likely pathogenic variants in two genes that encode interacting proteins previously only linked to orofacial clefting in mouse models. A variant in GDF11 (encoding growth differentiation factor 11), predicting a p.(Arg298Gln) substitution at the Furin protease cleavage site, was identified in one family that segregated with CL/P and both rib and vertebral hypersegmentation, mirroring that seen in Gdf11 knockout mice. In the second family in which CL/P was the only phenotype, a mutation in FST (encoding the GDF11 antagonist, Follistatin) was identified that is predicted to result in a p.(Cys56Tyr) substitution in the region that binds GDF11. Functional assays demonstrated a significant impact of the specific mutated amino acids on FST and GDF11 function and, together with embryonic expression data, provide strong evidence for the importance of GDF11 and Follistatin in the regulation of human orofacial development.
- Published
- 2018
28. Discovery and characterization of spontaneous mouse models of craniofacial dysmorphology
- Author
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Son Yong Karst, Timothy C. Cox, Suhaib Borgeia, Roderick T. Bronson, Mohamed G. Hassan, Laura G. Reinholdt, Harold F Coombs, Stephen A. Murray, Michelle Curtain, David E. Bergstrom, Louise A Dionne, Heather Fairfield, Leah Rae Donahue, and Kristina Palmer
- Subjects
Male ,0301 basic medicine ,Cephalometry ,Craniofacial abnormality ,Context (language use) ,Disease ,Biology ,Article ,Tooth Eruption ,Craniofacial Abnormalities ,Mice ,03 medical and health sciences ,Imaging, Three-Dimensional ,medicine ,Animals ,Humans ,Exome ,Gene Regulatory Networks ,Allele ,Craniofacial ,Maxillofacial Development ,Molecular Biology ,Gene ,Alleles ,Genetic Association Studies ,Genetics ,Skull ,Causative gene ,X-Ray Microtomography ,Cell Biology ,medicine.disease ,Phenotype ,Disease Models, Animal ,030104 developmental biology ,Face ,Osteopetrosis ,Mutation ,Female ,Developmental Biology - Abstract
Craniofacial abnormalities are among the most common features of human genetic syndromes and disorders. The etiology of these conditions is often complex, influenced by both genetic context and the environment. Frequently, craniofacial abnormalities present as part of a syndrome with clear comorbid phenotypes, providing additional insight into mechanisms of the causative gene or pathway. The mouse has been a key tool in our understanding of the genetic mechanisms of craniofacial development and disease, and can provide excellent models for human craniofacial abnormalities. While powerful genetic engineering tools in the mouse have contributed significantly our understanding of craniofacial development and dysmorphology, forward genetic approaches provide an unbiased means to identify new genes and pathways. Moreover, spontaneous mutations can occur on any number of genetic backgrounds, potentially revealing critical genes that require a specific genetic context. Here we report discovery and phenotyping of 43 craniofacial mouse models, derived primarily from a screen for spontaneous mutations in production colonies at the Jackson Laboratory. We identify the causative gene for 33 lines, including novel genes in pathways not previously connected to craniofacial development, and novel alleles of known genes that present with unique phenotypes. Together with our detailed characterization, this work provides a valuable gene discovery resource for the craniofacial community, and a rich source of mouse models for further investigation.
- Published
- 2016
29. SLC20A2 Deficiency in Mice Leads to Elevated Phosphate Levels in Cerbrospinal Fluid and Glymphatic Pathway-Associated Arteriolar Calcification, and Recapitulates Human Idiopathic Basal Ganglia Calcification
- Author
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Cecilia M. Giachelli, Suhaib Borgeia, Mary C. Wallingford, Timothy C. Cox, Chenphop Sawangmake, Jia Jun Chia, Elizabeth M. Leaf, Kenneth I. Marro, Nicholas W. Chavkin, and Mei Y. Speer
- Subjects
0301 basic medicine ,Pathology ,medicine.medical_specialty ,business.industry ,General Neuroscience ,Basal ganglia calcification ,medicine.disease ,Pathology and Forensic Medicine ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Cerebrospinal fluid ,medicine.anatomical_structure ,Basal ganglia ,medicine ,Choroid plexus ,Glymphatic system ,Neurology (clinical) ,business ,Ependyma ,Haploinsufficiency ,030217 neurology & neurosurgery ,Calcification - Abstract
Idiopathic basal ganglia calcification is a brain calcification disorder that has been genetically linked to autosomal dominant mutations in the sodium-dependent phosphate co-transporter, SLC20A2. The mechanisms whereby deficiency of Slc20a2 leads to basal ganglion calcification are unknown. In the mouse brain, we found that Slc20a2 was expressed in tissues that produce and/or regulate cerebrospinal fluid, including choroid plexus, ependyma and arteriolar smooth muscle cells. Haploinsufficient Slc20a2 +/- mice developed age-dependent basal ganglia calcification that formed in glymphatic pathway-associated arterioles. Slc20a2 deficiency uncovered phosphate homeostasis dysregulation characterized by abnormally high cerebrospinal fluid phosphate levels and hydrocephalus, in addition to basal ganglia calcification. Slc20a2 siRNA knockdown in smooth muscle cells revealed increased susceptibility to high phosphate-induced calcification. These data suggested that loss of Slc20a2 led to dysregulated phosphate homeostasis and enhanced susceptibility of arteriolar smooth muscle cells to elevated phosphate-induced calcification. Together, dysregulated cerebrospinal fluid phosphate and enhanced smooth muscle cell susceptibility may predispose to glymphatic pathway-associated arteriolar calcification.
- Published
- 2016
30. Microcomputed tomography of craniofacial mineralized tissue: A practical user's guide to study planning and generating quality data
- Author
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Timothy C. Cox
- Subjects
0301 basic medicine ,Mineralized tissues ,Histology ,Physiology ,Appendicular skeleton ,Computer science ,Endocrinology, Diabetes and Metabolism ,030209 endocrinology & metabolism ,Bone and Bones ,3D rendering ,Mice ,03 medical and health sciences ,Imaging, Three-Dimensional ,0302 clinical medicine ,medicine ,Animals ,Craniofacial ,business.industry ,Volume rendering ,X-Ray Microtomography ,Visualization ,030104 developmental biology ,medicine.anatomical_structure ,Data quality ,Tomography ,business ,Biomedical engineering - Abstract
Whether in a clinical setting or a research environment using model organisms, X-ray-based computed tomography (CT) in its different forms represents the gold standard technology for the non-invasive imaging and quantification of mineralized tissues. While there are many excellent reviews on computed tomography in bone imaging, most focus on the appendicular skeleton. However, the craniofacial skeleton and mineralized dentition, which are frequently imaged for a variety of reasons, can require special considerations to ensure the best quality data are acquired and interpreted correctly. In this review, I will specifically focus on micro-computed tomography (microCT) related to the study of the craniofacial skeleton from the onset of cranioskeletal development through to adulthood using the mouse as the primary reference organism. In so doing, I will cover the important considerations when planning imaging studies, explain critical parameters of both scanning, reconstruction and 3D rendering of data that can impact quantification of different mineralized craniofacial tissues, and options for enabling accurate visualization of tomographic data.
- Published
- 2020
31. Secreted metalloproteases ADAMTS9 and ADAMTS20 have a non-canonical role in ciliary vesicle growth during ciliogenesis
- Author
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Kay Grobe, Heon Yung Gee, Timothy C. Cox, Friedhelm Hildebrandt, Anna O’Donnell, Caroline M. Kraft, Rushabh Patel, Suneel S. Apte, Lauren W. Wang, and Sumeda Nandadasa
- Subjects
0301 basic medicine ,endocrine system ,Science ,General Physics and Astronomy ,ADAMTS9 Protein ,Mice, Transgenic ,02 engineering and technology ,Endocytosis ,Models, Biological ,General Biochemistry, Genetics and Molecular Biology ,Article ,Cell Line ,03 medical and health sciences ,chemistry.chemical_compound ,Gene Knockout Techniques ,Mice ,ADAMTS Proteins ,Versicans ,Ciliogenesis ,Animals ,Humans ,Cilia ,Neural Tube Defects ,lcsh:Science ,Yolk Sac ,Mice, Knockout ,Multidisciplinary ,Cilium ,General Chemistry ,Heparan sulfate ,021001 nanoscience & nanotechnology ,LRP1 ,Hedgehog signaling pathway ,Transmembrane protein ,3. Good health ,Cell biology ,030104 developmental biology ,chemistry ,Mutation ,Proteolysis ,Microscopy, Electron, Scanning ,lcsh:Q ,Signal transduction ,0210 nano-technology ,Signal Transduction - Abstract
Although hundreds of cytosolic or transmembrane molecules form the primary cilium, few secreted molecules are known to contribute to ciliogenesis. Here, homologous secreted metalloproteases ADAMTS9 and ADAMTS20 are identified as ciliogenesis regulators that act intracellularly. Secreted and furin-processed ADAMTS9 bound heparan sulfate and was internalized by LRP1, LRP2 and clathrin-mediated endocytosis to be gathered in Rab11 vesicles with a unique periciliary localization defined by super-resolution microscopy. CRISPR-Cas9 inactivation of ADAMTS9 impaired ciliogenesis in RPE-1 cells, which was restored by catalytically active ADAMTS9 or ADAMTS20 acting in trans, but not by their proteolytically inactive mutants. Their mutagenesis in mice impaired neural and yolk sac ciliogenesis, leading to morphogenetic anomalies resulting from impaired hedgehog signaling, which is transduced by primary cilia. In addition to their cognate extracellular proteolytic activity, ADAMTS9 and ADAMTS20 thus have an additional proteolytic role intracellularly, revealing an unexpected regulatory dimension in ciliogenesis., Ciliogenesis is a complex process requiring hundreds of molecules, although few secreted proteins have been implicated. Here, the authors show that the secreted metalloproteases ADAMTS9 and ADAMTS20 intracellularly regulate ciliogenesis from unique periciliary vesicles with proteolytic activity.
- Published
- 2018
32. A craniosynostosis massively parallel sequencing panel study in 309 Australian and New Zealand patients: findings and recommendations
- Author
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Michael Buckley, William Lo, Michael Gattas, Michael T. Gabbett, Mathew Wallis, David J. Amor, Fiona Haslam McKenzie, Felicity Collins, Nerine Gregersen, Kate Gibson, Simeon Boyd, Mary Louise Freckmann, Carol Ann Verrenkamp, Mark P. Gianoutsos, Eric Lee, Wanda Lattanzi, Ying Zhu, David Mowat, Tony Roscioli, Ravi Savarirayan, Zornitza Stark, Eric Haan, Tiong Yang Tan, Janine Smith, Maya Chopra, Ian Hayes, Trang T. Le, Sulekha Rajagopalan, Timothy C. Cox, George Elakis, Edwin P. Kirk, Anne M. Turner, Natasha J Brown, Nicole Snow, Hanka Venselaar, Alison Yeung, Rani Sachdev, Christopher P. Barnett, and Lesley C. Adès
- Subjects
Male ,0301 basic medicine ,Pediatrics ,Fibroblast Growth Factor ,Cohort Studies ,Basic Helix-Loop-Helix Transcription Factors ,coronal ,Settore BIO/13 - BIOLOGIA APPLICATA ,Prospective Studies ,panel ,Exome ,Genetics (clinical) ,Coronal craniosynostosis ,Massive parallel sequencing ,medicine.diagnostic_test ,craniosynostosis ,EFNB1 ,TCF12 ,Australia ,Cranial Sutures ,Craniosynostoses ,DNA-Binding Proteins ,Ephrin-B1 ,Female ,Fibroblast Growth Factor 10 ,Genetic Testing ,High-Throughput Nucleotide Sequencing ,Humans ,New Zealand ,Nuclear Proteins ,Receptor, Fibroblast Growth Factor, Type 1 ,Repressor Proteins ,Retrospective Studies ,Transcription Factors ,Twist-Related Protein 1 ,Receptor ,Type 1 ,Cohort study ,medicine.medical_specialty ,Craniosynostosis ,03 medical and health sciences ,All institutes and research themes of the Radboud University Medical Center ,medicine ,Genetic testing ,business.industry ,Retrospective cohort study ,medicine.disease ,030104 developmental biology ,business ,Nanomedicine Radboud Institute for Molecular Life Sciences [Radboudumc 19] - Abstract
Purpose : The craniosynostoses are characterized by premature fusion of one or more cranial sutures. The relative contribution of previously reported genes to craniosynostosis in large cohorts is unclear. Here we report on the use of a massively parallel sequencing panel in individuals with craniosynostosis without a prior molecular diagnosis. Methods : A 20-gene panel was designed based on the genes’ association with craniosynostosis, and clinically validated through retrospective testing of an Australian and New Zealand cohort of 233 individuals with craniosynostosis in whom previous testing had not identified a causative variant within FGFR1-3 hot-spot regions or the TWIST1 gene. An additional 76 individuals were tested prospectively. Results : Pathogenic or likely pathogenic variants in non-FGFR genes were identified in 43 individuals, with diagnostic yields of 14% and 15% in retrospective and prospective cohorts, respectively. Variants were identified most frequently in TCF12 (N = 22) and EFNB1 (N = 8), typically in individuals with nonsyndromic coronal craniosynostosis or TWIST1-negative clinically suspected Saethre–Chotzen syndrome. Clinically significant variants were also identified in ALX4, EFNA4, ERF, and FGF10. Conclusion : These findings support the clinical utility of a massively parallel sequencing panel for craniosynostosis. TCF12 and EFNB1 should be included in genetic testing for nonsyndromic coronal craniosynostosis or clinically suspected Saethre–Chotzen syndrome.
- Published
- 2018
33. Inhibition of Notch Signaling During Mouse Incisor Renewal Leads to Enamel Defects
- Author
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Ophir D. Klein, Michaela Prochazkova, Christian W. Siebel, Eli D. Sone, Bernhard Ganss, Bo Meng, Young Jun Lim, Andrew H. Jheon, Ruben Espinoza, Timothy Wen, Adrien Naveau, and Timothy C. Cox
- Subjects
0301 basic medicine ,Chemistry ,Endocrinology, Diabetes and Metabolism ,Notch signaling pathway ,Wnt signaling pathway ,Context (language use) ,Anatomy ,Fibroblast growth factor ,Cell biology ,Stratum intermedium ,stomatognathic diseases ,03 medical and health sciences ,Enamel mineralization ,030104 developmental biology ,stomatognathic system ,Orthopedics and Sports Medicine ,Ameloblast ,Adult stem cell - Abstract
The continuously growing rodent incisor is an emerging model for the study of renewal of mineralized tissues by adult stem cells. Although the Bmp, Fgf, Shh, and Wnt pathways have been studied in this organ previously, relatively little is known about the role of Notch signaling during incisor renewal. Notch signaling components are expressed in enamel-forming ameloblasts and the underlying stratum intermedium (SI), which suggested distinct roles in incisor renewal and enamel mineralization. Here, we injected adult mice with inhibitory antibodies against several components of the Notch pathway. This blockade led to defects in the interaction between ameloblasts and the SI cells, which ultimately affected enamel formation. Furthermore, Notch signaling inhibition led to the downregulation of desmosome-specific proteins such as PERP and desmoplakin, consistent with the importance of desmosomes in the integrity of ameloblast-SI attachment and enamel formation. Together, our data demonstrate that Notch signaling is critical for proper enamel formation during incisor renewal, in part by regulating desmosome-specific components, and that the mouse incisor provides a model system to dissect Jag-Notch signaling mechanisms in the context of mineralized tissue renewal.
- Published
- 2015
34. Utility and limitations of animal models for the functional validation of human sequence variants
- Author
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Timothy C. Cox
- Subjects
0303 health sciences ,Functional validation ,business.industry ,Computer science ,030305 genetics & heredity ,Data science ,3. Good health ,03 medical and health sciences ,Human sequence ,Animal model ,Invited Commentary ,Genetics ,Causation ,business ,Lagging ,Molecular Biology ,Publication ,Exome ,Genetics (clinical) ,030304 developmental biology ,Coding (social sciences) - Abstract
One of the biggest challenges facing us in this new age of genomic medicine is the functional validation of variants identified in exome/whole-genome sequencing approaches. The growing suite of bioinformatics tools provide powerful ways to filter and prioritize candidate genes as well as to offer predictions on the impact of coding variants on protein function. Yet, despite their usefulness in prioritizing candidates, these computational methodologies remain insufficiently robust to “prove” causation of, or contribution to, the phenotype of interest. When we serve as reviewers of manuscripts and grants we are often quick to remind authors of this fact and yet acknowledge that it is not always the easiest of tasks. The need for caution over the reliance on bioinformatics is, however, justified. This of course is not to say these pipelines are not incredibly valuable in themselves. Indeed, they more often than not stimulate formulation of biologically testable hypotheses from which the evidence in support of causation may come. But the limitation is that almost all bioinformatics tools are built around existing knowledge that is acquired from public and/or commercial data sources and so inherit the inaccuracies and limitations of any past experimentation that generated that original data and, to an extent, are implicitly affected by errors in curation that are unavoidably present in such sources. Existing tools also lack the power to interpret biological context, including the complexities of developmental processes and tissue physiology that is currently the aim of the systems biologists. With the massive accumulation of “omics”-scale data, some of this will undoubtedly change. However, nothing is currently as convincing or as powerful as in vivo data from a good animal model. Even then, one must know the strengths and limitations of the model system being utilized and, equally importantly, have the tools by which to characterize the phenotypic outcome both appropriately and with precision. There is increasing recognition of the need for detailed and precise clinical phenotyping but sadly this has been lagging behind when phenotyping animal models. The latter problem is likely compounded by the pressures to publish, the cut backs and competitiveness in the current funding climate, and perhaps an under-appreciation of the insight provided by a well-characterized model and the translational impact that may be gleaned from it. In this commentary, I wish to highlight the often difficult decisions we must face when confronted by a list of variants from genome-scale sequencing data and some key points to consider when deciding how to best test and validate any given variant as pathogenic.
- Published
- 2015
35. Digging adaptation in insectivorous subterranean eutherians. The enigma ofMesoscalops montanensisunveiled by geometric morphometrics and finite element analysis
- Author
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Gabriele Sansalone, Tassos Kotsakis, Paolo Colangelo, Marco Moscato, Ronald Eng, Luciano Teresi, Anna Loy, Antonio Profico, Timothy C. Cox, and Paolo Piras
- Subjects
Morphometrics ,Digging ,Talpidae ,biology ,Convergent evolution ,Fossorial ,Zoology ,Animal Science and Zoology ,Context (language use) ,Mammal ,Phylogenetic comparative methods ,biology.organism_classification ,Developmental Biology - Abstract
The enigmatic Early Miocene fossorial mammal Mesoscalops montanensis shows one of the most modified humeri among terrestrial mammals. It has been suggested, on qualitative considerations, that this species has no extant homologues for humerus kinematics and that, functionally, the closest extant group is represented by Chrysochloridae. We combine here three dimensional geometric morphometrics, finite element analysis and phylogenetic comparative methods to explore the shape and mechanical stress states of Mesoscalops montanensis as well as of extant and extinct Talpidae and Chrysochloridae under realistic digging simulations. Evolutionary convergence analyses reveal that the shape of Mesoscalops montanensis represents a unique morphology in the context of fossorial mammals and that its functional performance, albeit superficially similar to that of extant Chrysochloridae, still represents a nonconvergent optimum for adaptation to digging. J. Morphol. 276:1157–1171, 2015. © 2015 Wiley Periodicals, Inc.
- Published
- 2015
36. Osseous Characteristics of Mice Lacking Cannabinoid Receptor 2 after Pulp Exposure
- Author
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Natasha M. Flake, Elizabeth P. Nikolaeva, and Timothy C. Cox
- Subjects
Pathology ,medicine.medical_specialty ,Bone density ,Mandible ,Mandibular first molar ,Bone resorption ,Bone remodeling ,Receptor, Cannabinoid, CB2 ,Mice ,stomatognathic system ,Bone Density ,medicine ,Animals ,Dental Pulp Exposure ,Bone Resorption ,General Dentistry ,Mice, Knockout ,Bone mineral ,business.industry ,Increased Bone Density ,stomatognathic diseases ,Pulp (tooth) ,Female ,lipids (amino acids, peptides, and proteins) ,Periapical bone loss ,business ,Periapical Periodontitis - Abstract
Endogenous cannabinoid compounds are involved in many physiological processes, including bone metabolism. Cannabinoid receptor 2 (CB2) plays a role in modulating bone density, but published research results are conflicting. Furthermore, the specific role of CB2 in inflammation-induced bone resorption and craniofacial bone density has not been reported. The objective of this study was to assess the role of CB2 in dental pulp exposure-induced periapical bone loss and mandibular bone density.Adult female wild-type (WT) and CB2 homozygous knockout (KO) mice were used. Pulp exposures were created unilaterally in the mandibular first molars, and the pulp was left exposed to the oral cavity to induce periapical lesion formation. Mandibles were harvested 26 days after pulp exposure. Mandibular bone mineral density and periapical lesion volume were assessed using micro-computed tomographic imaging.Periapical lesion volume measured on the mesial root of the pulp-exposed first molar was significantly less in CB2 KO than WT mice (P.05). No significant difference was detected between KO and WT mice in the size of the PDL space measured on the mesial root of the contralateral intact first molar. CB2 KO mice exhibited greater mandibular bone density than WT mice (P.05).CB2 plays a role in mandibular bone metabolism. Increased bone density in CB2 KO mice may contribute to the smaller periapical lesion size observed after pulp exposure in KO compared with WT mice. Additional experiments are needed to further elucidate the function of CB2 and clinical implications of cannabinoids on bone and periapical pathosis.
- Published
- 2015
37. PiT-2, a type III sodium-dependent phosphate transporter, protects against vascular calcification in mice with chronic kidney disease fed a high-phosphate diet
- Author
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Shunsuke Yamada, Jia Jun Chia, Cecilia M. Giachelli, Mei Y. Speer, Elizabeth M. Leaf, and Timothy C. Cox
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Heterozygote ,Vascular smooth muscle ,Population ,Myocytes, Smooth Muscle ,Haploinsufficiency ,Phosphates ,03 medical and health sciences ,Mice ,Osteoprotegerin ,Bone Density ,Internal medicine ,medicine ,Animals ,Renal Insufficiency, Chronic ,education ,Vascular Calcification ,Uremia ,Mice, Knockout ,education.field_of_study ,Chemistry ,Sodium-Phosphate Cotransporter Proteins, Type III ,medicine.disease ,030104 developmental biology ,Endocrinology ,Nephrology ,Knockout mouse ,Female ,Biomarkers ,Kidney disease ,Calcification - Abstract
PiT-2, a type III sodium-dependent phosphate transporter, is a causative gene for the brain arteriolar calcification in people with familial basal ganglion calcification. Here we examined the effect of PiT-2 haploinsufficiency on vascular calcification in uremic mice using wild-type and global PiT-2 heterozygous knockout mice. PiT-2 haploinsufficiency enhanced the development of vascular calcification in mice with chronic kidney disease fed a high-phosphate diet. No differences were observed in the serum mineral biomarkers and kidney function between the wild-type and PiT-2 heterozygous knockout groups. Micro computed tomography analyses of femurs showed that haploinsufficiency of PiT-2 decreased trabecular bone mineral density in uremia. In vitro, sodium-dependent phosphate uptake was decreased in cultured vascular smooth muscle cells isolated from PiT-2 heterozygous knockout mice compared with those from wild-type mice. PiT-2 haploinsufficiency increased phosphate-induced calcification of cultured vascular smooth muscle cells compared to the wild-type. Furthermore, compared to wild-type vascular smooth muscle cells, PiT-2 deficient vascular smooth muscle cells had lower osteoprotegerin levels and increased matrix calcification, which was attenuated by osteoprotegerin supplementation. Thus, PiT-2 in vascular smooth muscle cells protects against phosphate-induced vascular calcification and may be a therapeutic target in the chronic kidney disease population.
- Published
- 2017
38. Cerebral perfusion characteristics show differences in younger versus older children with sickle cell anaemia: Results from a multiple-inflow-time arterial spin labelling study
- Author
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Simon Barker, Chris A. Clark, Timothy C. Cox, Fenella J. Kirkham, Jamie M. Kawadler, and Patrick W. Hales
- Subjects
Male ,medicine.medical_specialty ,Time Factors ,Adolescent ,Posterior cerebral artery ,Anemia, Sickle Cell ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Cerebral circulation ,0302 clinical medicine ,Internal medicine ,medicine.artery ,medicine ,Anterior cerebral artery ,Humans ,Radiology, Nuclear Medicine and imaging ,Cerebral perfusion pressure ,Child ,Spectroscopy ,Cerebral infarction ,business.industry ,Age Factors ,Cerebral Arteries ,medicine.disease ,Transcranial Doppler ,Oxygen ,Perfusion ,Cerebral blood flow ,Cerebrovascular Circulation ,Middle cerebral artery ,Cardiology ,Molecular Medicine ,Female ,Spin Labels ,business ,030217 neurology & neurosurgery - Abstract
Sickle cell anaemia (SCA) is associated with chronic anaemia and oxygen desaturation, which elevate cerebral blood flow (CBF) and increase the risk of neurocognitive complications. Arterial spin labelling (ASL) provides a methodology for measuring CBF non-invasively; however, ASL techniques using only a single inflow time are not sufficient to fully characterize abnormal haemodynamic behaviour in SCA. This study investigated haemodynamic parameters from a multi-inflow-time ASL acquisition in younger (8-12 years) and older (13-18 years) children with SCA with and without silent cerebral infarction (SCI+/-) (n = 20 and 19 respectively, 6 and 4 SCI+ respectively) and healthy controls (n = 9 and 7 respectively). Compared with controls, CBF was elevated globally in both groups of patients. In the younger SCA patients, blood oxygen content was negatively correlated with CBF in the middle and posterior cerebral artery territories and significantly positively correlated with bolus arrival time (BAT) in the anterior and middle cerebral artery territories. In older children, SCA patients had significantly shorter BAT than healthy controls and there was a significant negative correlation between CBF and oxygen content only in the territory of the posterior cerebral artery, with a trend for a correlation in the anterior cerebral artery but no relationship for the middle cerebral artery territory. In the younger group, SCI+ patients had significantly higher CBF in the posterior cerebral artery territory (SCI+ mean = 92.78 ml/100 g/min; SCI- mean = 72.71 ml/100 g/min; F = 4.28, p = 0.04), but this no longer reached significance when two children with abnormal transcranial Doppler and one with haemoglobin SC disease were excluded, and there were no significant differences between patients with and without SCI in the older children. With age, there appears to be increasing disparity between patients and controls in terms of the relationship between CBF and oxygen content in the anterior circulation, potentially predicting the risk of acute and chronic compromise of brain tissue.
- Published
- 2017
39. The genetics of auricular development and malformation: New findings in model systems driving future directions for microtia research
- Author
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Daniela V Luquetti, Timothy C. Cox, Siddharth R. Vora, Esra D. Camci, and Eric E. Turner
- Subjects
Craniofacial microsomia ,Classification scheme ,Goldenhar syndrome ,Biology ,Mouse models ,Article ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Quantitative assessment ,Anotia ,Genetics ,Animals ,Humans ,Genetics(clinical) ,Genetics (clinical) ,030304 developmental biology ,Congenital Microtia ,0303 health sciences ,Microtia ,General Medicine ,Anatomy ,medicine.disease ,OAVS ,Evolutionary biology ,Auricular development ,Identification (biology) ,030217 neurology & neurosurgery ,Ear Auricle - Abstract
Microtia is a term used to describe a wide array of phenotypic presentations of the outer ear. Although the majority of the cases are isolated in nature, much of our understanding of the causes of microtia has been driven by the identification of genes underlying syndromic forms where the anomaly co-presents with various other craniofacial and extra-craniofacial structural defects. In this review we discuss recent findings in mice deficient in Hoxa2, a key regulator of branchial arch patterning, which has necessitated a revision to the canonical model of pinna morphogenesis. The revised model will likely impact current classification schemes for microtia and, as we argue in this review, the interpretation of the developmental basis for various auricular malformations. In addition, we highlight recent studies in other mammalian species that are providing the first clues as to possible causes of at least some isolated anomalies and thus should now accelerate the search for the more elusive genetic contributions to the many isolated and non-syndromic cases of microtia. These findings, together with the application of new genome-level sequencing technologies and more thorough quantitative assessment of available mutant mouse resources, promise an exciting future for genetic studies in microtia.
- Published
- 2014
- Full Text
- View/download PDF
40. Phenotypic characterization of new mouse model of class III malocclusion
- Author
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Mohamed G. Hassan, Hanan Ismail, Timothy C. Cox, and Mohamed Mowafy
- Subjects
Genetics ,Class iii malocclusion ,Biology ,Characterization (mathematics) ,Phenotype - Published
- 2013
41. Microtomographic Analysis of Lower Urinary Tract Obstruction
- Author
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Joseph R. Siebert, Kenneth J. Smith, Liza L Cox, Timothy C. Cox, and Ian A. Glass
- Subjects
Male ,Urethral Obstruction ,Urinary Bladder ,urologic and male genital diseases ,Article ,Pathology and Forensic Medicine ,Fetus ,Pregnancy ,Prune belly syndrome ,medicine ,Humans ,Tomography, Optical ,Hydronephrosis ,Urethral crest ,Urinary bladder ,business.industry ,X-Ray Microtomography ,General Medicine ,Megacystis ,Anatomy ,medicine.disease ,Prostatic utricle ,medicine.anatomical_structure ,Urethra ,Pediatrics, Perinatology and Child Health ,Female ,Urinary tract obstruction ,business - Abstract
Prenatal obstruction of the lower urinary tract may result in megacystis, with subsequent development of hydroureter, hydronephrosis, and renal damage. Oligo- or anhydramnios, pulmonary hypoplasia, and prune belly syndrome are lethal consequences. Causes and mechanisms responsible for obstruction remain unclear but might be clarified by anatomic study at autopsy. To this end, we employed 2 methods of tomographic imaging—optical projection tomography and contrast-enhanced microCT scanning—to elucidate the anatomy of the intact urinary bladder and urethra in 10 male fetuses with lower urinary tract obstruction. Images were compared with those from 9 age-matched controls. Three-dimensional images, rotated and sectioned digitally in multiple planes, permitted thorough examination while preserving specimens for later study. Both external and internal features of the bladder and urethra were demonstrated; small structures (ie, urethral crest, verumontanum, prostatic utricle, ejaculatory ducts) were seen in detail. Types of obstruction consisted of urethral atresia ( n = 5), severe urethral stenosis ( n = 2), urethral diaphragm ( n = 2), or physical kinking ( n = 1); classic (Young type I) posterior urethral valves were not encountered. Traditional light microscopy was then used to verify tomographic findings. The prostate gland was hypoplastic or absent in all cases; in 1, prostatic tissue was displaced inferior to the verumontanum. Findings support previous views that dissection may produce valve-like artifacts (eg, bisection of an obstructing diaphragm) and that deformation of an otherwise normal urethra may result in megacystis. The designation “posterior urethral valves” should not be used as a generic expression of urethral obstruction unless actual valves are demonstrated.
- Published
- 2013
42. Perspectives and challenges in advancing research into craniofacial anomalies
- Author
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Timothy C. Cox, Michael L. Cunningham, and Daniela V Luquetti
- Subjects
Robin Sequence ,business.industry ,Dentistry ,Genomics ,Biology ,medicine.disease ,Medical care ,Standardized terminology ,Craniosynostosis ,Evolutionary biology ,Genetics ,medicine ,Craniofacial ,business ,Genetic diagnosis ,Surgical interventions ,Genetics (clinical) - Abstract
Development of the craniofacial region is a remarkably complex and tightly orchestrated process. It is therefore not surprising that genetic and environmental insults frequently result in craniofacial anomalies. Nonetheless, our knowledge of their etiology and pathogenesis is still scarce, limiting our efforts at prevention. Furthermore, few standardized protocols have been developed to guide clinical and surgical interventions. In this Issue of the Seminars, reviews on the most recent research advances on craniofacial conditions, from genomics and epigenetics to ontology and medical care are discussed with emphasis on the most common anomalies of the craniofacial region: orofacial clefts, craniosynostosis, craniofacial microsomia, facial dysostosis, Robin sequence, jaw and dentition anomalies, and anterior neural tube defects. Phenotypic variability and the importance of detailed characterization using standardized terminology to better distinguish between phenotypes, new technologies (and their limitations) for genetic diagnosis, and the use of mouse models to study these conditions in both their complex phenotypic and genetic aspects are highlighted.
- Published
- 2013
43. Genotype and clinical care correlations in craniosynostosis: Findings from a cohort of 630 Australian and New Zealand patients
- Author
-
Susan M. White, Tiong Yang Tan, Lisa Worgan, Emma L. Hackett, Michael Gattas, David Mowat, Michael Field, Hanka Venselaar, George McGillivray, Felicity Collins, Edwin P. Kirk, Michael F. Buckley, Alison Colley, David J. David, Julie McGaughran, Trang T. Le, Michael T. Gabbett, David J. Amor, Timothy C. Cox, Rani Sachdev, Anne M. Turner, Mary-Louise Freckmann, Eric Haan, Peter J. Anderson, Kate Gibson, Ian A. Glass, Benjamin Kamien, Mark P. Gianoutsos, Joanne Dixon, David J. Moon, Tony Roscioli, Meredith Wilson, Matthew S. Edwards, Elizabeth Thompson, Lies H. Hoefsloot, Anna Hackett, George Elakis, Ravi Savarirayan, and L. C. Adès
- Subjects
Proband ,Sanger sequencing ,Genetics ,medicine.medical_specialty ,Acrocephalosyndactylia ,Apert syndrome ,Biology ,medicine.disease ,Craniosynostosis ,symbols.namesake ,Genotype ,medicine ,symbols ,Pfeiffer syndrome ,Medical genetics ,Genetics (clinical) - Abstract
Craniosynostosis is one of the most common craniofacial disorders encountered in clinical genetics practice, with an overall incidence of 1 in 2,500. Between 30% and 70% of syndromic craniosynostoses are caused by mutations in hotspots in the fibroblast growth factor receptor (FGFR) genes or in the TWIST1 gene with the difference in detection rates likely to be related to different study populations within craniofacial centers. Here we present results from molecular testing of an Australia and New Zealand cohort of 630 individuals with a diagnosis of craniosynostosis. Data were obtained by Sanger sequencing of FGFR1, FGFR2, and FGFR3 hotspot exons and the TWIST1 gene, as well as copy number detection of TWIST1. Of the 630 probands, there were 231 who had one of 80 distinct mutations (36%). Among the 80 mutations, 17 novel sequence variants were detected in three of the four genes screened. In addition to the proband cohort there were 96 individuals who underwent predictive or prenatal testing as part of family studies. Dysmorphic features consistent with the known FGFR1-3/TWIST1-associated syndromes were predictive for mutation detection. We also show a statistically significant association between splice site mutations in FGFR2 and a clinical diagnosis of Pfeiffer syndrome, more severe clinical phenotypes associated with FGFR2 exon 10 versus exon 8 mutations, and more frequent surgical procedures in the presence of a pathogenic mutation. Targeting gene hot spot areas for mutation analysis is a useful strategy to maximize the success of molecular diagnosis for individuals with craniosynostosis.
- Published
- 2013
44. The ontology of craniofacial development and malformation for translational craniofacial research
- Author
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Carrie L. Heike, Landon T. Detwiler, Michael R. Clarkson, José L. V. Mejino, James F. Brinkley, M. J. Cunningham, Charles D. Borromeo, Ravensara S. Travillian, Timothy C. Cox, Linda G. Shapiro, and Harry Hochheiser
- Subjects
Knowledge representation and reasoning ,Craniofacial abnormality ,Mechanism (biology) ,Foundational Model of Anatomy ,Computational biology ,Biology ,Ontology (information science) ,medicine.disease ,computer.software_genre ,Bioinformatics ,FaceBase ,Genetics ,medicine ,Craniofacial ,computer ,Genetics (clinical) ,Data integration - Abstract
We introduce the Ontology of Craniofacial Development and Malformation (OCDM) as a mechanism for representing knowledge about craniofacial development and malformation, and for using that knowledge to facilitate integrating craniofacial data obtained via multiple techniques from multiple labs and at multiple levels of granularity. The OCDM is a project of the NIDCR-sponsored FaceBase Consortium, whose goal is to promote and enable research into the genetic and epigenetic causes of specific craniofacial abnormalities through the provision of publicly accessible, integrated craniofacial data. However, the OCDM should be usable for integrating any web-accessible craniofacial data, not just those data available through FaceBase. The OCDM is based on the Foundational Model of Anatomy (FMA), our comprehensive ontology of canonical human adult anatomy, and includes modules to represent adult and developmental craniofacial anatomy in both human and mouse, mappings between homologous structures in human and mouse, and associated malformations. We describe these modules, as well as prototype uses of the OCDM for integrating craniofacial data. By using the terms from the OCDM to annotate data, and by combining queries over the ontology with those over annotated data, it becomes possible to create "intelligent" queries that can, for example, find gene expression data obtained from mouse structures that are precursors to homologous human structures involved in malformations such as cleft lip. We suggest that the OCDM can be useful not only for integrating craniofacial data, but also for expressing new knowledge gained from analyzing the integrated data.
- Published
- 2013
45. The MID1 E3 Ligase Catalyzes the Polyubiquitination of Alpha4 (α4), a Regulatory Subunit of Protein Phosphatase 2A (PP2A)
- Author
-
Haijuan Du, Erica Walters, Timothy C. Cox, Michael A. Massiah, Yongzhao Huang, and Manar Zaghlula
- Subjects
biology ,Protein subunit ,Lactacystin ,Cell Biology ,Protein phosphatase 2 ,Protein degradation ,Biochemistry ,Ubiquitin ligase ,chemistry.chemical_compound ,chemistry ,Ubiquitin ,Proteasome inhibitor ,medicine ,biology.protein ,Monoubiquitination ,Molecular Biology ,medicine.drug - Abstract
Alpha4 (α4) is a key regulator of protein phosphatase 2A (PP2A) and mTOR in steps essential for cell-cycle progression. α4 forms a complex with PP2A and MID1, a microtubule-associated ubiquitin E3 ligase that facilitates MID1-dependent regulation of PP2A and the dephosphorylation of MID1 by PP2A. Ectopic overexpression of α4 is associated with hepatocellular carcinomas, breast cancer, and invasive adenocarcinomas. Here, we provide data suggesting that α4 is regulated by ubiquitin-dependent degradation mediated by MID1. In cells stably expressing a dominant-negative form of MID1, significantly elevated levels of α4 were observed. Treatment of cells with the specific proteasome inhibitor, lactacystin, resulted in a 3-fold increase in α4 in control cells and a similar level in mutant cells. Using in vitro assays, individual MID1 E3 domains facilitated monoubiquitination of α4, whereas full-length MID1 as well as RING-Bbox1 and RING-Bbox1-Bbox2 constructs catalyzed its polyubiquitination. In a novel non-biased functional screen, we identified a leucine to glutamine substitution at position 146 within Bbox1 that abolished MID1-α4 interaction and the subsequent polyubiquitination of α4, indicating that direct binding to Bbox1 was necessary for the polyubiquitination of α4. The mutant had little impact on the RING E3 ligase functionality of MID1. Mass spectrometry data confirmed Western blot analysis that ubiquitination of α4 occurs only within the last 105 amino acids. These novel findings identify a new role for MID1 and a mechanism of regulation of α4 that is likely to impact the stability and activity level of PP2Ac.
- Published
- 2013
46. No evidence for cumulative effects in a Dnmt3b hypomorph across multiple generations
- Author
-
Sarah K. Harten, Krystal L. Lester, Neil A. Youngson, Emma Whitelaw, Timothy C. Cox, Graham F. Kay, Jacqueline M. Matthews, Alyson Ashe, Trevor Epp, Suyinn Chong, Amity Rondalyne Roberts, Edward Huang, and Lucia Daxinger
- Subjects
Male ,Genetics ,Methyltransferase ,Base Sequence ,Homozygote ,Molecular Sequence Data ,DNMT3B ,Bisulfite sequencing ,Mice, Transgenic ,Exons ,DNA Methylation ,Biology ,Epigenesis, Genetic ,Pedigree ,Chromatin ,Mice ,DNA methylation ,Animals ,Female ,DNA (Cytosine-5-)-Methyltransferases ,Allele ,Gene ,Reprogramming ,Alleles - Abstract
Observations of inherited phenotypes that cannot be explained solely through genetic inheritance are increasing. Evidence points to transmission of non-DNA molecules in the gamete as mediators of the phenotypes. However, in most cases it is unclear what the molecules are, with DNA methylation, chromatin proteins, and small RNAs being the most prominent candidates. From a screen to generate novel mouse mutants of genes involved in epigenetic reprogramming, we produced a DNA methyltransferase 3b allele that is missing exon 13. Mice that are homozygous for the mutant allele have smaller stature and reduced viability, with particularly high levels of female post-natal death. Reduced DNA methylation was also detected at telocentric repeats and the X-linked Hprt gene. However, none of the abnormal phenotypes or DNA methylation changes worsened with multiple generations of homozygous mutant inbreeding. This suggests that in our model the abnormalities are reset each generation and the processes of transgenerational epigenetic reprogramming are effective in preventing their inheritance.
- Published
- 2013
47. A likely role for the PH-domain containing protein, PEPP2/ PLEKHA5, at the membrane-microtubule cytoskeleton interface
- Author
-
Yi Zou and Timothy C Cox
- Subjects
Pleckstrin homology domain ,Microviscosity ,Membrane ,FERM domain ,Microtubule ,Microtubule cytoskeleton ,General Medicine ,Biology ,Cytoskeleton ,Function (biology) ,Cell biology - Abstract
PH (pleckstrin homology) domains are well known to bind membrane phosphoinositides with different specificities and direct PH domain-containing proteins to discrete subcellular compartments with as - sistances of alternative binding partners. PH domain-containing proteins have been found to be involved in a wide range of cellular events, including signalling, cytoskeleton rearrangement and vesicular trafficking. Here we showed that a novel PH domain-containing protein, PEPP2 (also known as PLEKHA5), displays mode- rate phosphoinositide binding specificity. Full length PEPP2 was observed to variably associate with both the plasma membrane and microtubules. The membrane-associated PEPP2 nucleated at cell-cell contacts and the leading edge of migrating cells. Overexpression of PEPP2 increased membrane microviscosity, in- dicating a potential role for PEPP2 in regulating function of microtubule-dependent membrane functions.
- Published
- 2013
48. Negative regulation of endothelin signaling by SIX1 is required for proper maxillary development
- Author
-
Heide L. Ford, Robert M. Maxson, Andre L.P. Tavares, David E. Clouthier, and Timothy C. Cox
- Subjects
0301 basic medicine ,JAG1 ,Biology ,Models, Biological ,Craniofacial Abnormalities ,03 medical and health sciences ,Mice ,0302 clinical medicine ,stomatognathic system ,medicine ,Maxilla ,Animals ,Serrate-Jagged Proteins ,Molecular Biology ,Body Patterning ,Homeodomain Proteins ,Zygoma ,Endothelin-1 ,Integrases ,Receptors, Notch ,Mandible ,Neural crest ,Gene Expression Regulation, Developmental ,Anatomy ,Embryo, Mammalian ,Receptor, Endothelin A ,Endothelin 1 ,Cell biology ,Up-Regulation ,030104 developmental biology ,medicine.anatomical_structure ,Branchial Region ,Neural Crest ,Sp7 Transcription Factor ,Endoderm ,Signal transduction ,Homeotic gene ,030217 neurology & neurosurgery ,Pharyngeal arch ,Developmental Biology ,Signal Transduction ,Transcription Factors ,Research Article - Abstract
Jaw morphogenesis is a complex event mediated by inductive signals that establish and maintain the distinct developmental domains required for formation of hinged jaws, the defining feature of gnathostomes. The mandibular portion of pharyngeal arch one is patterned dorsally by JAGGED-NOTCH signaling and ventrally by Endothelin receptor-A (EDNRA) signaling. Loss of EDNRA signaling disrupts normal ventral gene expression, the result of which is homeotic transformation of the mandible into a maxilla-like structure. However, loss of JAGGED-NOTCH signaling does not result in significant changes in maxillary development. Here we show that the transcription factor SIX1 regulates dorsal arch development not only by inducing dorsal Jag1 expression but also by inhibiting Endothelin1 (Edn1) expression in the pharyngeal endoderm of the dorsal arch, thus preventing dorsal EDNRA signaling. In the absence of SIX1, but not JAG1, aberrant EDNRA signaling in the dorsal domain results in partial duplication of the mandible. Together, our results illustrate that SIX1 is the central mediator of dorsal mandibular arch identity, thus ensuring separation of bone development between the upper and lower jaws.
- Published
- 2016
49. A distal 594 bp ECR specifies Hmx1 expression in pinna and lateral facial morphogenesis and is regulated by the Hox-Pbx-Meis complex
- Author
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Victor Latorre, Wenjie Li, Jessica M. Rosin, Nicoletta Bobola, Jennifer A. Akiyama, Takashi Kuramoto, Axel Visel, Eric E. Turner, Timothy C. Cox, Liza L Cox, and S. M. Rolfe
- Subjects
0301 basic medicine ,Mouse ,medicine.disease_cause ,Medical and Health Sciences ,Transgenic ,Conserved sequence ,Craniofacial Abnormalities ,Mice ,Hmx1 ,Genes, Reporter ,Gene duplication ,Morphogenesis ,Developmental ,Hox gene ,Base Pairing ,Conserved Sequence ,Genetics ,Mutation ,Evolutionarily conserved region ,Pre-B-Cell Leukemia Transcription Factor 1 ,Gene Expression Regulation, Developmental ,Biological Sciences ,Cell biology ,Mutant Strains ,Enhancer Elements, Genetic ,Organ Specificity ,Research Article ,Protein Binding ,Ear Auricle ,Enhancer Elements ,Sensory Receptor Cells ,Evolution ,Mice, Transgenic ,Biology ,Craniofacial mesenchyme ,Evolution, Molecular ,03 medical and health sciences ,Genetic ,Physical Stimulation ,medicine ,Animals ,Enhancer ,Molecular Biology ,Transcription factor ,Reporter ,Homeodomain Proteins ,Base Sequence ,Molecular ,Mice, Mutant Strains ,030104 developmental biology ,Gene Expression Regulation ,Genes ,Face ,Homeobox ,Pinna ,Developmental Biology ,Transcription Factors - Abstract
Hmx1 encodes a homeodomain transcription factor expressed in the developing lateral craniofacial mesenchyme, retina and sensory ganglia. Mutation or mis-regulation of Hmx1 underlies malformations of the eye and external ear in multiple species. Deletion or insertional duplication of an evolutionarily conserved region (ECR) downstream of Hmx1 has recently been described in rat and cow, respectively. Here, we demonstrate that the impact of Hmx1 loss is greater than previously appreciated, with a variety of lateral cranioskeletal defects, auriculofacial nerve deficits, and duplication of the caudal region of the external ear. Using a transgenic approach, we demonstrate that a 594 bp sequence encompassing the ECR recapitulates specific aspects of the endogenous Hmx1 lateral facial expression pattern. Moreover, we show that Hoxa2, Meis and Pbx proteins act cooperatively on the ECR, via a core 32 bp sequence, to regulate Hmx1 expression. These studies highlight the conserved role for Hmx1 in BA2-derived tissues and provide an entry point for improved understanding of the causes of the frequent lateral facial birth defects in humans.
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- 2016
50. Abstract 167: Doxycycline Inhibits Revascularization After Hindlimb Ischemia
- Author
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Timothy C. Cox, Galit Ankri Eliahoo, George Fu, Richard D. Kenagy, and Gale L. Tang
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Doxycycline ,medicine.medical_specialty ,business.industry ,Internal medicine ,medicine.medical_treatment ,medicine ,Cardiology ,Hindlimb ischemia ,Cardiology and Cardiovascular Medicine ,Revascularization ,business ,medicine.drug - Abstract
Objectives: p27 kip1 , a gene affecting human response to arterial injury, affects collateralization after hindlimb ischemia (femoral artery ligation), possibly by regulating matrix metalloproteinase 2 (MMP2). We hypothesized that MMP2 mRNA expression would increase significantly more in ko mice after hindlimb ischemia and that MMP inhibition would affect p27 -/- (ko) collateralization less than p27 +/+ (wt). Methods: Ko and wt mice had their femoral and collateral arteries harvested seven days after hindlimb ischemia for RNA isolation and qRT-PCR. Ko and wt mice were also fed chow without or with doxycycline (a broad spectrum MMP inhibitor) and subjected to hindlimb ischemia. The mice were followed with weekly footpad laser Doppler perfusion imaging for 28 days, and then sacrificed for microCT scanning. Vascular smooth muscle cells (VSMC) isolated from either wt or ko aortae were used in Boyden chamber migration assays without and with an MMP2 specific inhibitor. Results: MMP2 mRNA expression increased significantly more in ko collaterals than wt collaterals (312% vs. 50%, respectively). However, blood flow recovery in ko and wt mice treated with doxycycline decreased to a similar extent (27±2.5% and 33±1% decrease respectively), although ko mice still revascularized better than wt mice ( p < 0.01). Gracilis collateral diameters increased less after doxycycline treatment in both groups compared to mice fed regular chow (78.5±12 and 80±7 vs 98±18 and 106±17 μm, respectively). The bridge collateral diameters increased less in ko mice fed doxycycline (66±32 vs 158±18.3 μm), and no bridge collaterals were detected in wt mice fed doxycycline. Wt mice fed regular chow had rare bridge collaterals. Ko VSMC migration was less affected by MMP2 inhibition than wt (29% less migration vs 48% less migration, p Conclusions: MMP2 mRNA expression increased significantly more in p27 ko collaterals after hindlimb ischemia. The non-specific MMP inhibitor doxycycline inhibited revascularization after hindlimb ischemia, independent of p27 expression. p27 ko mice still revascularized better than wt mice after doxycycline treatment, suggesting that p27 has additional effects other than regulating MMP expression in the collateralization response.
- Published
- 2016
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