17 results on '"Jasreen Kular"'
Search Results
2. Nano-Mechanical Analyses of Native and Cross-Linked Collagen I Matrices Reveal the Mechanical Complexity of Homogenous Samples
- Author
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Brock Alan Le Cerf, Natasha Theresa Pyne, Jasreen Kular, Sarah Theresa Boyle, David Allan Beattie, Marta Krasowska, and Michael Susithiran Samuel
- Subjects
extracellular matrix ,collagen ,atomic force microscopy (AFM) ,fourier transform infrared spectroscopy (FTIR) ,nanomechanical properties ,Physics ,QC1-999 - Abstract
While it is now well appreciated that the extracellular matrix (ECM) exerts biomechanical cues that direct critical cellular behavior, including cell proliferation, differentiation, migration, and survival, the molecular mechanisms underlying these cues remain mysterious. It has long been known that the ECM is also a source of biochemical cues that influence these processes, but the way these interact with ECM biomechanics also remains largely unknown. The systematic study of these relationships has been hampered by a paucity of models and the tools to interrogate them. Studies of complex models and tissue samples employing techniques such as atomic force microscopy (AFM) have informed much of our current understanding of how mechanical cues are transduced by the ECM and how cells respond to them. However, key observations made using such complex systems cannot be reliably assigned to the ECM or its components without a precise understanding of how these components respond to and exert mechanical force at the nanoscale – the scale at which individual cells respond. To address this knowledge gap, we used AFM to study the nanomechanical properties of a simple model, consisting only of type I collagen, the most abundant component of the ECM. Intriguingly, our data show bimodal distribution that is entirely attributable to type I collagen, greatly simplifying the interpretation of these studies. Furthermore, we examined the nanomechanical influence of tissue fixation by protein cross-linking, an approach commonly used in research and medical histopathology, revealing a significant and non-uniform distortion of the nanomechanical profile of fixed samples, which has the potential to introduce artifacts into the nanomechanical characterization of tissues. In contrast to the clear observation of mechanical differences induced by cross-linking, Fourier-transform infrared (FTIR) spectroscopy revealed only subtle alterations to the chemical signature of the collagen, highlighting the importance of nanomechanical approaches for the complete characterization of model systems and tissues.
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- 2022
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3. ROCK-mediated selective activation of PERK signalling causes fibroblast reprogramming and tumour progression through a CRELD2-dependent mechanism
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Natasha T. Pyne, Marina Kochetkova, Andrew I. Webb, Alexander C. Lewis, Kendelle J. Murphy, Paul Timpson, Paul A.B. Moretti, Melinda N. Tea, Stuart M. Pitson, Angel F. Lopez, Sarah T. Boyle, Natasha Kolesnikoff, Vinay Tergaonkar, Jasreen Kular, Robert Whitfield, Jarrod J. Sandow, Valentina Poltavets, and Michael S. Samuel
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endocrine system ,0303 health sciences ,EIF-2 kinase ,Kinase ,Endoplasmic reticulum ,ATF4 ,Paracrine Communication ,Cell Biology ,Biology ,3. Good health ,Cell biology ,03 medical and health sciences ,Paracrine signalling ,0302 clinical medicine ,030220 oncology & carcinogenesis ,Unfolded protein response ,biology.protein ,Cancer-Associated Fibroblasts ,030304 developmental biology - Abstract
It is well accepted that cancers co-opt the microenvironment for their growth. However, the molecular mechanisms that underlie cancer-microenvironment interactions are still poorly defined. Here, we show that Rho-associated kinase (ROCK) in the mammary tumour epithelium selectively actuates protein-kinase-R-like endoplasmic reticulum kinase (PERK), causing the recruitment and persistent education of tumour-promoting cancer-associated fibroblasts (CAFs), which are part of the cancer microenvironment. An analysis of tumours from patients and mice reveals that cysteine-rich with EGF-like domains 2 (CRELD2) is the paracrine factor that underlies PERK-mediated CAF education downstream of ROCK. We find that CRELD2 is regulated by PERK-regulated ATF4, and depleting CRELD2 suppressed tumour progression, demonstrating that the paracrine ROCK-PERK-ATF4-CRELD2 axis promotes the progression of breast cancer, with implications for cancer therapy.
- Published
- 2020
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4. Sugar transporter Slc37a2 regulates bone metabolism via a dynamic tubular lysosomal network in osteoclasts
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Pei Ying Ng, Amy B.P. Ribet, Qiang Guo, Benjamin H. Mullin, Jamie W.Y. Tan, Euphemie Landao-Bassonga, Sébastien Stephens, Kai Chen, Laila Abudulai, Maike Bollen, Edward T.T.T. Nguyen, Jasreen Kular, John M. Papadimitriou, Kent Søe, Rohan D. Teasdale, Jiake Xu, Robert G. Parton, Hiroshi Takanayagi, and Nathan J. Pavlos
- Abstract
Osteoclasts are giant bone-digesting cells that harbour specialized lysosome-related organelles termed secretory lysosomes (SLs). SLs store cathepsin K and serve as a membrane precursor to the ruffled border, the osteoclast’s ‘resorptive apparatus’. Yet, the molecular composition and spatiotemporal organization of SLs remains incompletely understood. Here, using organelle-resolution proteomics, we identify member a2 of the solute carrier 37 family (Slc37a2) as a SL sugar transporter. We demonstrate that Slc37a2 localizes to the SL limiting membrane and that these organelles adopt a hitherto unnoticed but dynamic tubular network in living osteoclasts that is required for bone digestion. Accordingly, mice lacking Slc37a2 accrue high bone mass owing to uncoupled bone metabolism and disturbances in SL export of monosaccharide sugars, a prerequisite for SL delivery to the ruffled border. Thus, Slc37a2 is a physiological component of the osteoclast’s unique secretory organelle and a potential therapeutic target for metabolic bone diseases.
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- 2022
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5. Acute compressive stress activates RHO/ROCK-mediated cellular processes
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Boyle, Sarah T., Jasreen Kular, Nobis, Max, Ruszkiewicz, Andrew, Timpson, Paul, and Samuel, Michael S.
- Abstract
The ability to rapidly respond to applied force underpins cell/tissue homeostasis. This response is mediated by mechanotransduction pathways that regulate remodeling and tension of the actomyosin cytoskeleton to counterbalance external forces. Enhanced extracellular matrix tension hyper-activates mechanotransduction and characterizes diseased states such as cancer, but is also required for normal epidermal regeneration. While the impact of extracellular matrix tension on signaling and cell biology are well appreciated, that of acute compressive force is under-studied. We show here that acute compressive force applied to cells and tissues in a native 3-dimensional context elevates RHOA-GTP levels and increases regulatory myosin phosphorylation, actomyosin contractility and tension via ROCK. In consequence, cell proliferation was increased, as was the expression of regulators of epithelial-mesenchymal transition. Pharmacological inhibition of ROCK abrogated myosin phosphorylation, but not RHOA activation. Our results strongly suggest that acute compressive stress impairs cellular homeostasis in a RHO/ROCK-dependent manner, with implications for disease states such as cancer.
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- 2020
- Full Text
- View/download PDF
6. ROCK-mediated selective activation of PERK signalling causes fibroblast reprogramming and tumour progression through a CRELD2-dependent mechanism
- Author
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Sarah Theresa, Boyle, Valentina, Poltavets, Jasreen, Kular, Natasha Theresa, Pyne, Jarrod John, Sandow, Alexander Charles, Lewis, Kendelle Joan, Murphy, Natasha, Kolesnikoff, Paul Andre Bartholomew, Moretti, Melinda Nay, Tea, Vinay, Tergaonkar, Paul, Timpson, Stuart Maxwell, Pitson, Andrew Ian, Webb, Robert John, Whitfield, Angel Francisco, Lopez, Marina, Kochetkova, and Michael Susithiran, Samuel
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Extracellular Matrix Proteins ,rho-Associated Kinases ,Breast Neoplasms ,Cellular Reprogramming ,Endoplasmic Reticulum ,Activating Transcription Factor 4 ,Disease Models, Animal ,Mice ,eIF-2 Kinase ,Cancer-Associated Fibroblasts ,Paracrine Communication ,Animals ,Humans ,Female ,Cell Adhesion Molecules ,Cells, Cultured - Abstract
It is well accepted that cancers co-opt the microenvironment for their growth. However, the molecular mechanisms that underlie cancer-microenvironment interactions are still poorly defined. Here, we show that Rho-associated kinase (ROCK) in the mammary tumour epithelium selectively actuates protein-kinase-R-like endoplasmic reticulum kinase (PERK), causing the recruitment and persistent education of tumour-promoting cancer-associated fibroblasts (CAFs), which are part of the cancer microenvironment. An analysis of tumours from patients and mice reveals that cysteine-rich with EGF-like domains 2 (CRELD2) is the paracrine factor that underlies PERK-mediated CAF education downstream of ROCK. We find that CRELD2 is regulated by PERK-regulated ATF4, and depleting CRELD2 suppressed tumour progression, demonstrating that the paracrine ROCK-PERK-ATF4-CRELD2 axis promotes the progression of breast cancer, with implications for cancer therapy.
- Published
- 2019
7. Publisher Correction: ROCK-mediated selective activation of PERK signalling causes fibroblast reprogramming and tumour progression through a CRELD2-dependent mechanism
- Author
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Sarah T. Boyle, Alexander C. Lewis, Paul Timpson, Angel F. Lopez, Marina Kochetkova, Robert Whitfield, Jarrod J. Sandow, Natasha T. Pyne, Melinda N. Tea, Vinay Tergaonkar, Valentina Poltavets, Michael S. Samuel, Natasha Kolesnikoff, Stuart M. Pitson, Jasreen Kular, Andrew I. Webb, Kendelle J. Murphy, and Paul A.B. Moretti
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0303 health sciences ,Mechanism (biology) ,Chemistry ,Cell Biology ,Cell biology ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Signalling ,medicine ,Fibroblast ,Reprogramming ,030217 neurology & neurosurgery ,030304 developmental biology - Published
- 2020
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8. Cytoplasmic dynein regulates the subcellular localization of sphingosine kinase 2 to elicit tumor-suppressive functions in glioblastoma
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Cassandra Stefanidis, Claudine S. Bonder, Briony L. Gliddon, Maurizio Costabile, Melinda N. Tea, Melissa R. Pitman, Julia R. Zebol, Paul A.B. Moretti, Heidi A. Neubauer, Brett W. Stringer, Bryan W. Day, Stuart M. Pitson, Jason A. Powell, Jasreen Kular, Michael S. Samuel, Neubauer, Heidi A, Tea, Melinda N, Zebol, Julia R, Gliddon, Briony L, Stefanidis, Cassandra, Moretti, Paul AB, Pitman, Melissa R, Costabile, Maurizio, Kular, Jasreen, Stringer, Brett W, Day, Bryan W, Samuel, Michael S, Bonder, Claudine S, Powell, Jason A, and Pitson, Stuart M
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0301 basic medicine ,Cytoplasmic Dyneins ,Cancer Research ,Carcinogenesis ,Apoptosis ,Biology ,Article ,Cell membrane ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Sphingosine ,Cell Line, Tumor ,Genetics ,medicine ,Animals ,Humans ,Genes, Tumor Suppressor ,Molecular Biology ,Cell Proliferation ,Kinase ,Cell growth ,Endoplasmic reticulum ,Cell Membrane ,Sphingosine Kinase 2 ,cell signalling ,Subcellular localization ,Xenograft Model Antitumor Assays ,Cell biology ,Gene Expression Regulation, Neoplastic ,CNS cancer ,Phosphotransferases (Alcohol Group Acceptor) ,030104 developmental biology ,medicine.anatomical_structure ,HEK293 Cells ,chemistry ,Cytoplasm ,030220 oncology & carcinogenesis ,Lysophospholipids ,Glioblastoma - Abstract
While the two mammalian sphingosine kinases, SK1 and SK2, both catalyze the generation of pro-survival sphingosine 1-phosphate (S1P), their roles vary dependent on their different subcellular localization. SK1 is generally found in the cytoplasm or at the plasma membrane where it can promote cell proliferation and survival. SK2 can be present at the plasma membrane where it appears to have a similar function to SK1, but can also be localized to the nucleus, endoplasmic reticulum or mitochondria where it mediates cell death. Although SK2 has been implicated in cancer initiation and progression, the mechanisms regulating SK2 subcellular localization are undefined. Here, we report that SK2 interacts with the intermediate chain subunits of the retrograde-directed transport motor complex, cytoplasmic dynein 1 (DYNC1I1 and -2), and we show that this interaction, particularly with DYNC1I1, facilitates the transport of SK2 away from the plasma membrane. DYNC1I1 is dramatically downregulated in patient samples of glioblastoma (GBM), where lower expression of DYNC1I1 correlates with poorer patient survival. Notably, low DYNC1I1 expression in GBM cells coincided with more SK2 localized to the plasma membrane, where it has been recently implicated in oncogenesis. Re-expression of DYNC1I1 reduced plasma membrane-localized SK2 and extracellular S1P formation, and decreased GBM tumor growth and tumor-associated angiogenesis in vivo. Consistent with this, chemical inhibition of SK2 reduced the viability of patient-derived GBM cells in vitro and decreased GBM tumor growth in vivo. Thus, these findings demonstrate a tumor-suppressive function of DYNC1I1, and uncover new mechanistic insights into SK2 regulation which may have implications in targeting this enzyme as a therapeutic strategy in GBM. Refereed/Peer-reviewed
- Published
- 2019
9. Acute compressive stress activates RHO/ROCK-mediated cellular processes
- Author
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Paul Timpson, Max Nobis, Sarah T. Boyle, Andrew Ruszkiewicz, Jasreen Kular, Michael S. Samuel, Boyle, Sarah T, Kular, Jasreen, Nobis, Max, Ruszkiewicz, Andrew, Timpson, Paul, and Samuel, Michael S
- Subjects
RHOA ,cytoskeleton ,compressive stress ,extracellular matrix (ECM) ,mechano-reciprocity ,mechanical signaling ,Context (language use) ,macromolecular substances ,Biochemistry ,Extracellular matrix ,03 medical and health sciences ,0302 clinical medicine ,Stress, Physiological ,ROCK ,Humans ,Mechanotransduction ,Cytoskeleton ,Tissue homeostasis ,Cells, Cultured ,030304 developmental biology ,actomyosintension ,0303 health sciences ,rho-Associated Kinases ,biology ,Cell growth ,Regeneration (biology) ,actomyosin tension ,Cell Biology ,Actomyosin ,Cell biology ,HEK293 Cells ,030220 oncology & carcinogenesis ,Research Paper/Report ,biology.protein ,rhoA GTP-Binding Protein ,Signal Transduction ,Research Article - Abstract
The ability to rapidly respond to applied force underpins cell/tissue homeostasis. This response is mediated by mechanotransduction pathways that regulate remodeling and tension of the actomyosin cytoskeleton to counterbalance external forces. Enhanced extracellular matrix tension hyper-activates mechanotransduction and characterizes diseased states such as cancer, but is also required for normal epidermal regeneration. While the impact of extracellular matrix tension on signaling and cell biology are well appreciated, that of acute compressive force is under-studied. We show here that acute compressive force applied to cells and tissues in a native 3-dimensional context elevates RHOA-GTP levels and increases regulatory myosin phosphorylation, actomyosin contractility and tension via ROCK. In consequence, cell proliferation was increased, as was the expression of regulators of epithelial-mesenchymal transition. Pharmacological inhibition of ROCK abrogated myosin phosphorylation, but not RHOA activation. Our results strongly suggest that acute compressive stress impairs cellular homeostasis in a RHO/ROCK-dependent manner, with implications for disease states such as cancer. Refereed/Peer-reviewed
- Published
- 2018
10. Non-severe burn injury leads to depletion of bone volume that can be ameliorated by inhibiting TNF-α
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Emily O’Halloran, Jiake Xu, Fiona M. Wood, Mark W. Fear, and Jasreen Kular
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Pathology ,medicine.medical_specialty ,Burn injury ,Bone density ,Critical Care and Intensive Care Medicine ,Bone tissue ,Bone remodeling ,Mice ,Internal medicine ,medicine ,Animals ,Femur ,Tumor Necrosis Factor-alpha ,business.industry ,X-Ray Microtomography ,General Medicine ,Bone Diseases, Metabolic ,medicine.anatomical_structure ,Endocrinology ,Emergency Medicine ,Surgery ,Cortical bone ,Burns ,business ,Total body surface area ,Glucocorticoid ,medicine.drug - Abstract
Bone loss after severe burn injury is well established, and is thought to be a consequence of the severe hyper-metabolic response as well as changes in cytokine and glucocorticoid levels that decrease bone synthesis and increase rate of loss. However, 90% of presentations are for non-severe burns which do not elicit this response. Little is known about whether these non-severe injuries may also affect bone tissue, and whether other mechanisms may be involved. To investigate whether bone loss occurs after a non-severe burn injury we used a mouse model of an approximately 8% total body surface area (TBSA) full-thickness burn and micro-CT. We also assessed whether blocking TNF-α after a burn injury by administration of an antibody could modulate the impacts of the burn on bone tissue. There was a significant loss of trabecular bone volume of (3.27% compared to 5.27%, p=0.0051) after non-severe burn injury. Trabecular number was significantly decreased (0.57/mm after injury compared to 1.02/mm controls, p=0.0051) and spacing increased after burn injury (0.40 compared to 0.28, p=0.0083). Anti-TNF-α antibodies significantly improved trabecular bone volume (8.53%, p=0.0034) and number after burn injury (1.28/mm, p=0.0034). There was no significant change observed in cortical bone after burn injury or administration of anti-TNF-α antibodies. These findings show that non-severe burn injury can lead to changes in bone metabolism. Monitoring bone density in patients with non-severe injuries and interventions to limit the impacts of the inflammatory storm may benefit patient recovery and outcomes.
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- 2015
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11. Incidence of BRAF p.Val600Glu and p.Val600Lys mutations in a consecutive series of 183 metastatic melanoma patients from a high incidence region
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Michael Millward, Barry Iacopetta, Fabienne Grieu, Benhur Amanuel, and Jasreen Kular
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Male ,Proto-Oncogene Proteins B-raf ,Pathology ,medicine.medical_specialty ,Skin Neoplasms ,Endemic Diseases ,DNA Mutational Analysis ,medicine.disease_cause ,Pathology and Forensic Medicine ,Metastasis ,Exon ,Genotype ,medicine ,Humans ,Point Mutation ,Neoplasm Metastasis ,Vemurafenib ,Melanoma ,neoplasms ,Mutation ,business.industry ,Point mutation ,DNA, Neoplasm ,Middle Aged ,medicine.disease ,Cancer research ,Female ,business ,V600E ,medicine.drug - Abstract
Summary Aim Approximately 40-60% of melanomas from Caucasian populations carry activating mutations in the BRAF oncogene, with the most common being the p.Val600Glu (V600E) hotspot mutation in exon 15. The aim of the present study was to investigate the frequency of the less common p.Val600Lys (V600K) mutation in metastatic melanoma from a high incidence region. Method Dideoxy sequencing and fluorescent single strand conformation analysis were used to screen for mutations in exon 15 of BRAF in 183 cases of metastatic melanoma. Results The overall incidence of BRAF mutation (89/183, 49%) was very similar to other large studies of Caucasian populations. However, the frequency of the p.Val600Lys mutation was higher than in most other studies and comprised almost one-third of all BRAF mutations in our cohort (27/89, 30%). Conclusion BRAF p.Val600Lys mutations were present at a relatively high frequency in this cohort of metastatic melanoma patients (27/183, 15%). Assays used to screen for BRAF mutations in the clinic should be robust enough to detect the p.Val600Lys mutation, as this may have therapeutic implications.
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- 2012
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12. Choline kinase β mutant mice exhibit reduced phosphocholine, elevated osteoclast activity, and low bone mass
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Xiaohong Yang, Honghui Chen, Robert W. Cook, Jiake Xu, Nathan J. Pavlos, Minghao Zheng, Jennifer Tickner, Livia C. Hool, Tamara N. Abel, Helena M. Viola, Jasreen Kular, and Bay Sie Lim
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musculoskeletal diseases ,Choline kinase ,Cellular differentiation ,Phosphorylcholine ,Osteoclasts ,Mice, Transgenic ,Biology ,Biochemistry ,Bone resorption ,Bone and Bones ,chemistry.chemical_compound ,Mice ,Osteoclast ,Bone Density ,medicine ,Animals ,Choline Kinase ,Homeostasis ,Bone Resorption ,Molecular Biology ,Phosphocholine ,Cell Proliferation ,Osteoblasts ,Cell growth ,Osteoblast ,Molecular Bases of Disease ,Cell Biology ,X-Ray Microtomography ,musculoskeletal system ,Cell biology ,medicine.anatomical_structure ,Phenotype ,chemistry ,Microscopy, Fluorescence ,Mutagenesis ,Mutation ,Calcium - Abstract
The maintenance of bone homeostasis requires tight coupling between bone-forming osteoblasts and bone-resorbing osteoclasts. However, the precise molecular mechanism(s) underlying the differentiation and activities of these specialized cells are still largely unknown. Here, we identify choline kinase β (CHKB), a kinase involved in the biosynthesis of phosphatidylcholine, as a novel regulator of bone homeostasis. Choline kinase β mutant mice (flp/flp) exhibit a systemic low bone mass phenotype. Consistently, osteoclast numbers and activity are elevated in flp/flp mice. Interestingly, osteoclasts derived from flp/flp mice exhibit reduced sensitivity to excessive levels of extracellular calcium, which could account for the increased bone resorption. Conversely, supplementation of cytidine 5'-diphosphocholine in vivo and in vitro, a regimen that bypasses CHKB deficiency, restores osteoclast numbers to physiological levels. Finally, we demonstrate that, in addition to modulating osteoclast formation and function, loss of CHKB corresponds with a reduction in bone formation by osteoblasts. Taken together, these data posit CHKB as a new modulator of bone homeostasis.
- Published
- 2014
13. An overview of the regulation of bone remodelling at the cellular level
- Author
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Jasreen Kular, Shek Man Chim, Jiake Xu, and Jennifer Tickner
- Subjects
Bone remodeling period ,Osteoblasts ,Osteoimmunology ,Macrophages ,Clinical Biochemistry ,Endothelial Cells ,Osteoclasts ,Osteoblast ,General Medicine ,Biology ,Bone and Bones ,Bone remodeling ,Cell biology ,Paracrine signalling ,Bone Diseases, Metabolic ,medicine.anatomical_structure ,Osteoclast ,Osteocyte ,Bone cell ,Immunology ,medicine ,Animals ,Humans ,Bone Remodeling ,Lymphocytes - Abstract
Objectives To review the current literature on the regulation of bone remodelling at the cellular level. Design and methods The cellular activities of the cells in the basic multicellular unit (BMU) were evaluated. Results Bone remodelling requires an intimate cross-talk between osteoclasts and osteoblasts and is tightly coordinated by regulatory proteins that interact through complex autocrine/paracrine mechanisms. Osteocytes, bone lining cells, osteomacs, and vascular endothelial cells also regulate bone remodelling in the BMU via cell signalling networks of ligand–receptor complexes. In addition, through secreted and membrane-bound factors in the bone microenvironment, T and B lymphocytes mediate bone homeostasis in osteoimmunology. Conclusions Osteoporosis and other bone diseases occur because multicellular communication within the BMU is disrupted. Understanding the cellular and molecular basis of bone remodelling and the discovery of novel paracrine or coupling factors, such as RANKL, sclerostin, EGFL6 and semaphorin 4D, will lay the foundation for drug development against bone diseases.
- Published
- 2011
14. Myocyte Enhancer Factor 2 and Microphthalmia-associated Transcription Factor Cooperate with NFATc1 to Transactivate the V-ATPase d2 Promoter during RANKL-induced Osteoclastogenesis*S⃞
- Author
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Xu Feng, Ming H. Zheng, Haotian Feng, David A. Joyce, ChengLoon Leong, Nathan J. Pavlos, Taksum Cheng, Jasreen Kular, James H. Steer, Jianzhong Liu, and Jiake Xu
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Mef2 ,Transcriptional Activation ,Vacuolar Proton-Translocating ATPases ,Molecular Sequence Data ,Osteoclasts ,Biology ,Biochemistry ,Cell Line ,Mice ,Chlorocebus aethiops ,Transcriptional regulation ,STXBP1 ,Animals ,Promoter Regions, Genetic ,Molecular Biology ,Transcription factor ,Base Pairing ,Cell Nucleus ,Microphthalmia-Associated Transcription Factor ,Binding Sites ,integumentary system ,Base Sequence ,NFATC Transcription Factors ,MEF2 Transcription Factors ,Mechanisms of Signal Transduction ,RANK Ligand ,Cell Differentiation ,Cell Biology ,Microphthalmia-associated transcription factor ,Molecular biology ,Protein Transport ,Myogenic Regulatory Factors ,COS Cells ,Chromatin immunoprecipitation ,IRF4 ,Protein Binding - Abstract
The V-ATPase d2 protein constitutes an important subunit of the V-ATPase proton pump, which regulates bone homeostasis; however, currently little is known about its transcriptional regulation. Here, in an attempt to understand regulation of the V-ATPase d2 promoter, we identified the presence of NFATc1, microphthalmia-associated transcription factor (MITF)- and myocyte enhancer factor 2 (MEF2)-binding sites within the V-ATPase d2 promoter using complementary bioinformatic analyses, chromatin immunoprecipitation, and electromobility shift assay. Intriguingly, activation of the V-ATPase d2 promoter by NFATc1 was enhanced by either MEF2 or MITF overexpression. By comparison, coexpression of MITF and MEF2 did not further enhance V-ATPase d2 promoter activity above that of expression of MITF alone. Consistent with a role in transcriptional regulation, both NFATc1 and MITF proteins translocated from the cytosol to the nucleus during RANKL-induced osteoclastogenesis, whereas MEF2 persisted in the nucleus of both osteoclasts and their mononuclear precursors. Targeted mutation of the putative NFATc1-, MITF-, or MEF2-binding sites in the V-ATPase d2 promoter impaired its transcriptional activation. Additionally retroviral overexpression of MITF or MEF2 in RAW264.7 cells potentiated RANKL-induced osteoclastogenesis and V-ATPase d2 gene expression. Based on these data, we propose that MEF2 and MITF function cooperatively with NFATc1 to transactivate the V-ATPase d2 promoter during RANKL-induced osteoclastogenesis.
- Published
- 2009
15. Choline kinase beta is an important regulator of bone homeostasis
- Author
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Jasreen Kular, Jiake Xu, Yu Qian, Baysie Lim, Minghao Zheng, Esta Ang, Tamara Davey, and Jennifer Tickner
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medicine.medical_specialty ,Histology ,Endocrinology ,Physiology ,Chemistry ,Endocrinology, Diabetes and Metabolism ,Internal medicine ,medicine ,Regulator ,Homeostasis ,Choline kinase beta - Published
- 2010
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16. MEF2 and MITF cooperate with NFATc1 to activate V-ATPase subunit d2 promoter in RANKL-induced osteoclastogenesis
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David A. Joyce, Jiake Xu, Xu Feng, Nathan J. Pavlos, Minghao Zheng, Jasreen Kular, James H. Steer, Jiarong Liu, Haotian Feng, Tak Sum Cheng, and ChengLoon Leong
- Subjects
Mef2 ,Histology ,biology ,Physiology ,Chemistry ,RANKL ,Endocrinology, Diabetes and Metabolism ,Protein subunit ,Cancer research ,biology.protein ,V-ATPase ,Microphthalmia-associated transcription factor ,Cell biology - Published
- 2009
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17. Transcriptional activation of V-ATPase subunit d2 is regulated by NFATc1 in RANKL-induced osteoclastogenesis
- Author
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David A. Joyce, Nathan J. Pavlos, Xu Feng, Jianzhong Liu, Jiake Xu, James H. Steer, Taksum Cheng, Jasreen Kular, ChengLoon Leong, Minghao Zheng, and Haotian Feng
- Subjects
Histology ,biology ,Physiology ,RANKL ,Chemistry ,Endocrinology, Diabetes and Metabolism ,Protein subunit ,biology.protein ,V-ATPase ,Cell biology - Published
- 2008
- Full Text
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