124 results on '"Robertson KA"'
Search Results
2. Outpatient total body irradiation for pediatric patients undergoing stem cell transplantation
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Dagher, R, Robertson, KA, Lucas, KG, Emanuel, D, and Smith, FO
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- 1997
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3. Retinoic acid-induced expression of CD38 antigen in myeloid cells is mediated through retinoic acid receptor-alpha
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Drach, J., Mcqueen, T., Engel, H., Andreeff, M., Robertson, Ka, Collins, Sj, Malavasi, Fabio, and Mehta, K.
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Receptors, Retinoic Acid ,Drug Resistance ,Gene Expression ,Tretinoin ,Transfection ,Cell Line ,Interferon-gamma ,Leukemia, Promyelocytic, Acute ,Antigens, CD ,Bone Marrow ,Leukemia, Myelogenous, Chronic, BCR-ABL Positive ,Granulocyte Colony-Stimulating Factor ,Tumor Cells, Cultured ,Humans ,ADP-ribosyl Cyclase ,Membrane Glycoproteins ,Dose-Response Relationship, Drug ,Granulocyte-Macrophage Colony-Stimulating Factor ,Cell Differentiation ,Flow Cytometry ,Hematopoietic Stem Cells ,ADP-ribosyl Cyclase 1 ,Antigens, Differentiation ,Recombinant Proteins ,Clone Cells ,Kinetics ,Tetradecanoylphorbol Acetate ,Granulocytes - Abstract
CD38 is a leukocyte differentiation antigen that has been thought to be a phenotypic marker of different subpopulations of T- and B-lymphocytes. In myeloid cells, CD38 is expressed during early stages of differentiation. Virtually no information is available on regulation and functions of CD38. Recently we reported that all-trans-retinoic acid (ATRA) is a potent and highly specific inducer of CD38 expression in human promyelocytic leukemia cells. Here we report that ATRA-induced expression of CD38 antigen in myeloid cells is mediated through retinoic acid-alpha receptor (RAR alpha). ATRA failed to induce CD38 expression in a mutant subclone of the HL-60 myeloid leukemia cell line (designated HL-60R) that is relatively resistant to ATRA-induced granulocytic differentiation. Retroviral vector-mediated transduction of RA receptor (RAR alpha) into this HL-60R subclone completely restored the sensitivity of these cells to ATRA in terms of their ability to express CD38. In contrast, CD38 expression was not inducible by ATRA in HL-60R cells, transfected with a functional RAR beta, RAR gamma, or RXR alpha receptor. Induction of CD38 in acute promyelocytic and acute myeloblastic leukemia cells was independent of ATRA-induced cytodifferentiation. Following culture with ATRA, increased CD38 protein levels were also observed in normal CD34+ bone marrow cells, but not on normal circulating granulocytes. From these results, we conclude that CD38 is ATRA inducible in myeloid leukemia cells and normal CD34+ bone marrow cells. This effect is independent of differentiation and is mediated by RAR alpha in HL-60 cells, suggesting a similar role for RAR alpha in CD38 expression in other hematopoietic cells.
- Published
- 1994
4. Assessment of iron status and the role for iron-replacement therapy in anaemic cancer patients under the care of a specialist palliative care unit
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Robertson*, KA, primary and Hutchison, SMW, additional
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- 2009
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5. Retinoic acid-resistant HL-60R cells harbor a point mutation in the retinoic acid receptor ligand-binding domain that confers dominant negative activity
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Robertson, KA, primary, Emami, B, additional, and Collins, SJ, additional
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- 1992
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6. Retinoic acid receptors in myeloid leukemia: characterization of receptors in retinoic acid-resistant K-562 cells
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Robertson, KA, primary, Mueller, L, additional, and Collins, SJ, additional
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- 1991
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7. Training multidisciplinary biomedical informatics students: three years of experience.
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van Mulligen EM, Cases M, Hettne K, Molero E, Weeber M, Robertson KA, Oliva B, de la Calle G, Maojo V, van Mulligen, Erik M, Cases, Montserrat, Hettne, Kristina, Molero, Eva, Weeber, Marc, Robertson, Kevin A, Oliva, Baldomero, de la Calle, Guillermo, and Maojo, Victor
- Abstract
Objective: The European INFOBIOMED Network of Excellence recognized that a successful education program in biomedical informatics should include not only traditional teaching activities in the basic sciences but also the development of skills for working in multidisciplinary teams.Design: A carefully developed 3-year training program for biomedical informatics students addressed these educational aspects through the following four activities: (1) an internet course database containing an overview of all Medical Informatics and BioInformatics courses, (2) a BioMedical Informatics Summer School, (3) a mobility program based on a 'brokerage service' which published demands and offers, including funding for research exchange projects, and (4) training challenges aimed at the development of multi-disciplinary skills.Measurements: This paper focuses on experiences gained in the development of novel educational activities addressing work in multidisciplinary teams. The training challenges described here were evaluated by asking participants to fill out forms with Likert scale based questions. For the mobility program a needs assessment was carried out.Results: The mobility program supported 20 exchanges which fostered new BMI research, resulted in a number of peer-reviewed publications and demonstrated the feasibility of this multidisciplinary BMI approach within the European Union. Students unanimously indicated that the training challenge experience had contributed to their understanding and appreciation of multidisciplinary teamwork.Conclusion: The training activities undertaken in INFOBIOMED have contributed to a multi-disciplinary BMI approach. It is our hope that this work might provide an impetus for training efforts in Europe, and yield a new generation of biomedical informaticians. [ABSTRACT FROM AUTHOR]- Published
- 2008
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8. Use of a BamHI polymorphism in the factor IX gene for the determination of hemophilia B carrier status
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Hay, CW, Robertson, KA, Yong, SL, Thompson, AR, Growe, GH, and MacGillivray, RT
- Abstract
A BamHI polymorphism has been identified in the human factor IX gene. This polymorphism, which occurs in approximately 6% of X chromosomes, has been used to determine the carrier status of a female in a family with a history of hemophilia B. This family was uninformative for the previously reported TaqI and Xmnl polymorphisms in the factor IX gene.
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- 1986
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9. Good practices in provision of nuclear safeguards and security training courses at the Integrated Support Center for Nuclear Nonproliferation and Nuclear Security
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Kobayashi Naoki, Robertson Kalman A., Koizumi Mitsuo, and Naoi Yosuke
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Physics ,QC1-999 - Abstract
More than five years have passed since the Integrated Support Center for Nuclear Nonproliferation and Nuclear Security (ISCN) was established under the Japan Atomic Energy Agency (JAEA) in December 2010 and started its activities, in response to the commitment of Japan at the Nuclear Security Summit in Washington D.C.. The ISCN has been vigorously involved in capacity building assistance on nuclear nonproliferation (safeguards) and nuclear security, mainly in the Asian region. It has provided 105 training courses to 2901 participants in total as of August 2016. The ISCN plays a major role in strengthening nuclear nonproliferation and nuclear security in the region, and this can be considered one of the great results of the Nuclear Security Summit process. The ISCN has cooperated with the US Department of Energy/National Nuclear Security Administration (DOE/NNSA) and Sandia National Laboratories (SNL) to establish a base of instructors, particularly for the Center's flagship two-week courses, the Regional Training Course on Physical Protection of Nuclear Material and Facilities (RTC on PP) and the Regional Training Course on State Systems of Accounting for and Control of Nuclear Material (RTC on SSAC). Furthermore, the ISCN has provided training courses for experts in Japan, making the best use of the Center's knowledge and experience of organizing international courses. The ISCN has also started joint synchronized training with the Joint Research Centre of the European Commission (EC JRC) on nuclear safeguards. This paper describes the good practices at the ISCN through its five years of activities, focusing on its progress in nuclear safeguards and nuclear security training.
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- 2017
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10. Histological evaluation of AMPK signalling in primary breast cancer
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Purdie Colin A, Jordan Lee B, Kellock David, Thomson George, Bray Susan E, Robertson Katherine E, Quinlan Philip R, Baker Lee, Hadad Sirwan M, Hardie David G, Fleming Stewart, and Thompson Alastair M
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Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abstract Background AMP-activated protein kinase (AMPK) acts as a cellular fuel gauge that responds to energy stress by suppressing cell growth and biosynthetic processes, thus ensuring that energy-consuming processes proceed only if there are sufficient metabolic resources. Malfunction of the AMPK pathway may allow cancer cells to undergo uncontrolled proliferation irrespective of their molecular energy levels. The aim of this study was to examine the state of AMPK phosphorylation histologically in primary breast cancer in relation to clinical and pathological parameters. Methods Immunohistochemistry was performed using antibodies to phospho-AMPK (pAMPK), phospho-Acetyl Co-A Carboxylase (pACC) an established target for AMPK, HER2, ERα, and Ki67 on Tissue Micro-Array (TMA) slides of two cohorts of 117 and 237 primary breast cancers. The quick score method was used for scoring and patterns of protein expression were compared with clinical and pathological data, including a minimum 5 years follow up. Results Reduced signal, compared with the strong expression in normal breast epithelium, using a pAMPK antibody was demonstrated in 101/113 (89.4%) and 217/236 (91.9%) of two cohorts of patients. pACC was significantly associated with pAMPK expression (p = 0.007 & p = 0.014 respectively). For both cohorts, reduced pAMPK signal was significantly associated with higher histological grade (p = 0.010 & p = 0.021 respectively) and axillary node metastasis (p = 0.061 & p = 0.039 respectively). No significant association was found between pAMPK and any of HER2, ERα, or Ki67 expression, disease-free survival or overall survival. Conclusion This study extends in vitro evidence through immunohistochemistry to confirm that AMPK is dysfunctional in primary breast cancer. Reduced signalling via the AMPK pathway, and the inverse relationship with histological grade and axillary node metastasis, suggests that AMPK re-activation could have therapeutic potential in breast cancer.
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- 2009
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11. Antibiotics for the primary prevention of acute rheumatic fever: a meta-analysis
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Volmink Jimmy A, Robertson Katharine A, and Mayosi Bongani M
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Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Abstract Background Rheumatic fever continues to put a significant burden on the health of low socio-economic populations in low and middle-income countries despite the near disappearance of the disease in the developed world over the past century. Antibiotics have long been thought of as an effective method for preventing the onset of acute rheumatic fever following a Group-A streptococcal (GAS) throat infection; however, their use has not been widely adopted in developing countries for the treatment of sore throats. We have used the tools of systematic review and meta-analysis to quantify the effectiveness of antibiotic treatment for sore throat, with symptoms suggestive of group A streptococcal (GAS) infection, for the primary prevention of acute rheumatic fever. Methods Trials were identified through a systematic search of titles and abstracts found in the Cochrane Central Register of Controlled Trials (Cochrane Library Issue 4, 2003), MEDLINE (1966–2003), EMBASE (1966–2003), and the reference lists of identified studies. The selection criteria included randomised or quasi-randomised controlled trials comparing the effectiveness of antibiotics versus no antibiotics for the prevention of rheumatic fever in patients presenting with a sore throat, with or without confirmation of GAS infection, and no history of rheumatic fever. Results Ten trials (n = 7665) were eligible for inclusion in this review. The methodological quality of the studies, in general, was poor. All of the included trials were conducted during the period of 1950 and 1961 and in 8 of the 10 trials the study population consisted of young adult males living on United States military bases. Fixed effects, meta-analysis revealed an overall protective effect for the use of antibiotics against acute rheumatic fever of 70% (RR = 0.32; 95% CI = 0.21–0.48). The absolute risk reduction was 1.67% with an NNT of 53. When meta-analysis was restricted to include only trials evaluating penicillin, a protective effect of 80% was found (Fixed effect RR = 0.20, 95% CI = 0.11–0.36) with an NNT of 60. The marginal cost of preventing one case of rheumatic fever by a single intramuscular injection of penicillin is approximately US$46 in South Africa. Conclusion Antibiotics appear to be effective in reducing the incidence of acute rheumatic fever following an episode of suspected GAS pharyngitis. This effect may be achieved at relatively low cost if a single intramuscular penicillin injection is administered.
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- 2005
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12. Formative peer evaluation instrument for a team-based learning course: Content and construct validity.
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Robertson KA, Gunderman DJ, and Byram JN
- Abstract
Purpose: Team-based learning (TBL) is an evidence-based approach to promote teamwork. Peer evaluation (PE) is an essential component to shape future team engagement and promote reflection. As PEs vary in use, implementation, and assessment, this study establishes the content and construct validity of a formative PE tool for a TBL course., Methods: A ten-item instrument was developed based on a comprehensive review of PE literature and was critically edited by a team of experienced educators. Each student in a graduate histology course rated peers at two timepoints on a scale from Never to Always (0-3). The instrument's factor structure was analyzed by dividing the response set (D1 and D2); with D1 utilized for exploratory factor analysis (EFA) and D2 for confirmatory factor analysis (CFA). Cronbach's alpha assessed internal consistency., Results: Data from 158 students across four cohorts were included in the analyses (D1, D2 = 972). A three-factor solution had good overall internal consistency (alpha = 0.82), and within the subscales ranged from 0.67 to 0.81. The factor structures were resonant with existing literature on (1) preparation, (2) providing feedback , and (3) f eedback receptivity and attitude., Conclusion: This study establishes evidence of content and construct validity of a formative PE instrument for a TBL course.
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- 2024
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13. Embedding Assessment Literacy Can Enhance Graduate Attribute Development in a Biomedical Sciences Curriculum.
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Robertson KA, Hughes KJ, and Rhind SM
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- Humans, Literacy, Male, Female, Students psychology, Comprehension, Curriculum, Educational Measurement methods
- Abstract
This paper describes the successful implementation of an assessment literacy strategy within a Biomedical Sciences degree. Teaching was aligned with an assessment literacy framework and aimed to prepare undergraduates for a literature comprehension assessment. Students were introduced to the assessment purpose and an adapted Miller's pyramid model illustrated how the assessment contributed to competency development during their degree. Students read primary research papers and answered questions relating to the publications. They were then introduced to the processes of assessment and collaboratively graded answers of different standards. Finally, student and faculty grades were compared, differences considered, and key characteristics of answers discussed. Most students reported that they understood more about assessment standards than prior to the intervention [139/159 (87.4%)] and felt it had helped prepare them for their exam [138/159 (86.8%)]. The majority also reported they had increased confidence in evaluating data [118/159 (74%)], communicating their reasoning [113/159 (71%)] and considering what a reader needs to know [127/159 (79.9%)]. Students were asked to state the most important thing they had learned from the assessment literacy teaching. Notably, no responses referred to domain-specific knowledge. 129 free text responses were mapped to the University of Edinburgh graduate attribute framework. 93 (72%) statements mapped to the graduate attribute category "Research and Enquiry," 66 (51.16%) mapped to "Communication" and 21 (16.27%) mapped to "Personal and Intellectual Autonomy." To explore any longer-term impact of the assessment literacy teaching, a focus group was held with students from the same cohort, 2 years after the original intervention. Themes from this part of the study included that teaching had provided insights into standards and expectations for the assessment and the benefits of domain specific knowledge. A variety of aspects related to graduate attributes were also identified. Here, assessment literacy as a vehicle for graduate attribute development was an unexpected outcome. We propose that by explicitly engaging students with purpose, process, standards, and expectations, assessment literacy strategies may be used to successfully raise awareness of developmental progression, and enhance skills, aptitudes, and dispositions beneficial to Biomedical Sciences academic achievement and life after university., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Robertson, Hughes and Rhind.)
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- 2024
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14. First patient project: Engaging pathology through the donor dissection experience and its role in professionalism.
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Robertson KA, Organ JM, Yard M, and Byram JN
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- Humans, Professionalism education, Dissection education, Curriculum, Anatomy education, Students, Medical psychology, Education, Medical, Undergraduate methods
- Abstract
The peer-reviewed anatomical education literature thoroughly describes the benefits and drawbacks of donor dissection. Gross anatomy laboratory environments utilizing donor dissection are generally considered to be a premier environment where students foster non-traditional discipline-independent skills (NTDIS), including the acquisition of professionalism, empathy, resilience, emotional intelligence, and situational awareness. Therefore, this IRB-approved study explored the impact of a formal humanism and pathology thread, the first patient project (FPP), on the personal and professional development of pre-professional undergraduate students in a gross anatomy dissection-based course. Five reflections from each student were collected across four cohorts (n = 74 students, 370 reflections). A post-course questionnaire collected data on student perceptions of the project. The framework method was used to analyze reflection and free response data and descriptive statistics were performed on Likert-style items using Excel. Three themes were identified to encompass the impacts of the FPP on professional development and include: Socialization (through collective dissection experience and pathology), Humanistic Qualities (respect for the donor and their history, and introspection), and Content and Skills (technical and NTDIS, anatomical knowledge). The end of course FPP survey was completed by 29 students across three cohorts (65%) and their perspectives were generally favorable regarding the promotion of respect, empathy, and humanization of their donors. This study underscores the value of incorporating humanism, pathology, and reflection, facilitated through formal curriculum for pre-professional undergraduate students. It provides evidence of the positive impact on their personal and professional development, supporting the integration of NTDIS in curricula across various disciplines., (© 2023 The Authors. Anatomical Sciences Education published by Wiley Periodicals LLC on behalf of American Association for Anatomy.)
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- 2024
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15. I am an Educator: Investigating Professional Identity Formation using Social Cognitive Career Theory.
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Byram JN, Robertson KA, and Dilly CK
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- Career Choice, Cognition, Fellowships and Scholarships, Humans, Social Identification, Curriculum, Faculty, Medical
- Abstract
Phenomenon Clinician-educators (CE) are physicians who fill a unique role within academic medicine, as they are responsible both for patient care and for training future physicians via teaching, curricular design, and creation of educational scholarship. Development of a strong professional identity as an educator leads to greater career satisfaction and a higher likelihood of staying in academic medicine. However, little is known about how this identity develops, especially in the training environment where there are competing pressures to develop as a clinician and researcher. This study aimed to explore professional identity formation in residents and fellows interested in becoming educators. Approach: We used a longitudinal, qualitative approach to investigate professional identity formation in residents and fellows participating in the Clinician-Educator Training Pathway. The longitudinal nature allowed us to temporally explore which aspects of the program and experiences acted as barriers or facilitators of professional identity formation as a CE. Our study used the social cognitive career theory (SCCT) Career Choice Model, which considers contextual influences in addition to the three variables of self-efficacy beliefs, outcome expectations, and goals. Findings: We found that participants shared a common goal of building self-efficacy as an educator. Participants took actions to engage more deliberately in formal and informal teaching and acting as an educator by giving learner feedback, developing curricula, and consuming and conducting educational research, all of which increased self-efficacy as educators. At the beginning of the program, participants were unclear of the roles and trajectories followed to become CEs. Engaging with a community of CEs clarified pathways and presented role models that could be seen as possible selves. This study also elucidated contextual influences relating to personal factors, career opportunities, and potential for advancement that mediated the goals and actions taken by participants to become educators. Insights: This study demonstrates that the SCCT Career Choice Model provides an excellent framework for understanding professional identity formation in future educators. Our participants built self-efficacy, formed outcome expectations, and set goals and took specific actions toward the goal of becoming an educator. Participants tested the various role model attributes as possible selves to see how those would be effective in their own career. Reflection on expectations, career goals, and self-efficacy as a clinician and an educator can assist in identity formation as a CE and can assist those designing CE training programs to better support identity formation in their participants.
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- 2022
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16. An inexpensive retrospective standard setting method based on item facilities.
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McLachlan JC, Robertson KA, Weller B, and Sawdon M
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- Clinical Competence, Cohort Studies, Humans, Retrospective Studies, Educational Measurement, Research Design
- Abstract
Background: Standard setting is one of the most challenging aspects of assessment in high-stakes healthcare settings. The Angoff methodology is widely used, but poses a number of challenges, including conceptualisation of the just-passing candidate, and the time-cost of implementing the method. Cohen methodologies are inexpensive and rapid but rely on the performance of an individual candidate. A new method of standard setting, based on the entire cohort and every item, would be valuable., Methods: We identified Borderline candidates by reviewing their performance across all assessments in an academic year. We plotted the item scores of the Borderline candidates in comparison with Facility for the whole cohort and fitted curves to the resulting distribution., Results: It is observed that for any given Item, an equation of the form y ≈ C. e
Fx where y is the Facility of Borderline candidates on that Item, x is the observed Item Facility of the whole cohort, and C and F are constants, predicts the probable Facility for Borderline candidates over the test, in other words, the cut score for Borderline candidates. We describe ways of estimating C and F in any given circumstance, and suggest typical values arising from this particular study: that C = 12.3 and F = 0.021., Conclusions: C and F are relatively stable, and that the equation y = 12.3. e0.021x can rapidly be applied to the item Facility for every item. The average value represents the cut score for the assessment as a whole. This represents a novel retrospective method based on test takers. Compared to the Cohen method which draws on one score and one candidate, this method draws on all items and candidates in a test. We propose that it can be used to standard set a whole test, or a particular item where the predicted Angoff score is very different from the observed Facility.- Published
- 2021
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17. Cabozantinib for neurofibromatosis type 1-related plexiform neurofibromas: a phase 2 trial.
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Fisher MJ, Shih CS, Rhodes SD, Armstrong AE, Wolters PL, Dombi E, Zhang C, Angus SP, Johnson GL, Packer RJ, Allen JC, Ullrich NJ, Goldman S, Gutmann DH, Plotkin SR, Rosser T, Robertson KA, Widemann BC, Smith AE, Bessler WK, He Y, Park SJ, Mund JA, Jiang L, Bijangi-Vishehsaraei K, Robinson CT, Cutter GR, Korf BR, Blakeley JO, and Clapp DW
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- Adolescent, Adult, Anilides adverse effects, Anilides pharmacokinetics, Animals, Disease Models, Animal, Female, Genes, Neurofibromatosis 1, Humans, Male, Mice, Mice, Mutant Strains, Neurofibroma, Plexiform genetics, Neurofibroma, Plexiform pathology, Neurofibromatosis 1 genetics, Neurofibromatosis 1 pathology, Pain Measurement, Prospective Studies, Protein Kinase Inhibitors adverse effects, Protein Kinase Inhibitors pharmacokinetics, Protein Kinase Inhibitors therapeutic use, Pyridines adverse effects, Pyridines pharmacokinetics, Quality of Life, Receptor Protein-Tyrosine Kinases antagonists & inhibitors, Translational Research, Biomedical, Young Adult, Anilides therapeutic use, Neurofibroma, Plexiform drug therapy, Neurofibromatosis 1 drug therapy, Pyridines therapeutic use
- Abstract
Neurofibromatosis type 1 (NF1) plexiform neurofibromas (PNs) are progressive, multicellular neoplasms that cause morbidity and may transform to sarcoma. Treatment of Nf1
fl/fl ;Postn-Cre mice with cabozantinib, an inhibitor of multiple tyrosine kinases, caused a reduction in PN size and number and differential modulation of kinases in cell lineages that drive PN growth. Based on these findings, the Neurofibromatosis Clinical Trials Consortium conducted a phase II, open-label, nonrandomized Simon two-stage study to assess the safety, efficacy and biologic activity of cabozantinib in patients ≥16 years of age with NF1 and progressive or symptomatic, inoperable PN ( NCT02101736 ). The trial met its primary outcome, defined as ≥25% of patients achieving a partial response (PR, defined as ≥20% reduction in target lesion volume as assessed by magnetic resonance imaging (MRI)) after 12 cycles of therapy. Secondary outcomes included adverse events (AEs), patient-reported outcomes (PROs) assessing pain and quality of life (QOL), pharmacokinetics (PK) and the levels of circulating endothelial cells and cytokines. Eight of 19 evaluable (42%) trial participants achieved a PR. The median change in tumor volume was 15.2% (range, +2.2% to -36.9%), and no patients had disease progression while on treatment. Nine patients required dose reduction or discontinuation of therapy due to AEs; common AEs included gastrointestinal toxicity, hypothyroidism, fatigue and palmar plantar erythrodysesthesia. A total of 11 grade 3 AEs occurred in eight patients. Patients with PR had a significant reduction in tumor pain intensity and pain interference in daily life but no change in global QOL scores. These data indicate that cabozantinib is active in NF1-associated PN, resulting in tumor volume reduction and pain improvement.- Published
- 2021
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18. Successful Allogeneic Stem Cell Transplant in Pediatric Patients With Diminished Left Ventricular Ejection Fractions.
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Lyon SM, Schamberger MS, Delgado DC, Skiles JL, Goebel WS, Robertson KA, and Parent JJ
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- Cardiotoxicity etiology, Cardiotoxicity pathology, Child, Female, Follow-Up Studies, Heart Failure pathology, Humans, Infant, Leukemia, Myeloid, Acute pathology, Male, Prognosis, Retrospective Studies, Transplantation, Homologous, Ventricular Dysfunction, Left pathology, Antineoplastic Combined Chemotherapy Protocols adverse effects, Cardiotoxicity therapy, Heart Failure therapy, Hematopoietic Stem Cell Transplantation methods, Leukemia, Myeloid, Acute drug therapy, Ventricular Dysfunction, Left therapy
- Abstract
Chemotherapy-associated cardiotoxicity may delay or impair the ability to administer fully myeloablative chemotherapy for stem cell transplant in those with reduced left ventricular ejection fraction. Studies in adults have been inconsistent regarding the value of ejection fraction in predicting cardiotoxicity in the posttransplant period. Recent publications, however, have demonstrated successful stem cell transplantation in adults despite low ejection fractions. This case series highlights 2 pediatric patients who were successfully treated with stem cell transplantation without posttransplant cardiac complications, despite pretransplant ejection fractions of 38% and 29%.
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- 2020
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19. Image segmentation of plexiform neurofibromas from a deep neural network using multiple b-value diffusion data.
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Ho CY, Kindler JM, Persohn S, Kralik SF, Robertson KA, and Territo PR
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- Female, Humans, Male, Middle Aged, Deep Learning, Diffusion Magnetic Resonance Imaging methods, Neural Networks, Computer, Neurofibroma, Plexiform diagnostic imaging
- Abstract
We assessed the accuracy of semi-automated tumor volume maps of plexiform neurofibroma (PN) generated by a deep neural network, compared to manual segmentation using diffusion weighted imaging (DWI) data. NF1 Patients were recruited from a phase II clinical trial for the treatment of PN. Multiple b-value DWI was imaged over the largest PN. All DWI datasets were registered and intensity normalized prior to segmentation with a multi-spectral neural network classifier (MSNN). Manual volumes of PN were performed on 3D-T2 images registered to diffusion images and compared to MSNN volumes with the Sørensen-Dice coefficient. Intravoxel incoherent motion (IVIM) parameters were calculated from resulting volumes. 35 MRI scans were included from 14 subjects. Sørensen-Dice coefficient between the semi-automated and manual segmentation was 0.77 ± 0.016. Perfusion fraction (f) was significantly higher for tumor versus normal tissue (0.47 ± 0.42 vs. 0.30 ± 0.22, p = 0.02), similarly, true diffusion (D) was significantly higher for PN tumor versus normal (0.0018 ± 0.0003 vs. 0.0012 ± 0.0002, p < 0.0001). By contrast, the pseudodiffusion coefficient (D*) was significantly lower for PN tumor versus normal (0.024 ± 0.01 vs. 0.031 ± 0.005, p < 0.0001). Volumes generated by a neural network from multiple diffusion data on PNs demonstrated good correlation with manual volumes. IVIM analysis of multiple b-value diffusion data demonstrates significant differences between PN and normal tissue.
- Published
- 2020
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20. Early administration of imatinib mesylate reduces plexiform neurofibroma tumor burden with durable results after drug discontinuation in a mouse model of neurofibromatosis type 1.
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Armstrong AE, Rhodes SD, Smith A, Chen S, Bessler W, Ferguson MJ, Jiang L, Li X, Yuan J, Yang X, Yang FC, Robertson KA, Ingram DA, Blakeley JO, and Clapp DW
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- Animals, Drug Screening Assays, Antitumor, Humans, Mice, Mice, Transgenic, Neoplasms, Experimental genetics, Neoplasms, Experimental metabolism, Neoplasms, Experimental pathology, Neurofibroma, Plexiform genetics, Neurofibroma, Plexiform metabolism, Neurofibroma, Plexiform pathology, Neurofibromatosis 1 genetics, Neurofibromatosis 1 metabolism, Neurofibromatosis 1 pathology, Imatinib Mesylate administration & dosage, Neoplasms, Experimental prevention & control, Neurofibroma, Plexiform prevention & control, Neurofibromatosis 1 prevention & control
- Abstract
Background: Neurofibromatosis type 1 (NF1) is a common genetic disorder characterized by plexiform neurofibromas (pNF), which are thought to be congenital tumors that arise in utero and enlarge throughout life. Genetic studies in murine models delineated an indispensable role for the stem cell factor (SCF)/c-kit pathway in pNF initiation and progression. A subsequent phase 2 clinical trial using imatinib mesylate to inhibit SCF/c-kit demonstrated tumor shrinkage in a subset of preexisting pNF; however, imatinib's role on preventing pNF development has yet to be explored., Procedure: We evaluated the effect of imatinib dosed at 10-100 mg/kg/day for 12 weeks to one-month-old Nf1
flox/flox ;PostnCre(+) mice, prior to onset of pNF formation. To determine durability of response, we then monitored for pNF growth at later time points, comparing imatinib- with vehicle-treated mice. We assessed gross and histopathological analysis of tumor burden., Results: Imatinib administered preventatively led to a significant decrease in pNF number, even at doses as low as 10 mg/kg/day. Tumor development continued to be significantly inhibited after cessation of imatinib dosed at 50 and 100 mg/kg/day. In the cohort of treated mice that underwent prolonged follow-up, the size of residual tumors was significantly reduced as compared with age-matched littermates that received vehicle control., Conclusions: Early administration of imatinib inhibits pNF genesis in vivo, and effects are sustained after discontinuation of therapy. These findings may guide clinical use of imatinib in young NF1 patients prior to the substantial development of pNF., (© 2020 Wiley Periodicals LLC.)- Published
- 2020
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21. How old is too old? In vivo engraftment of human peripheral blood stem cells cryopreserved for up to 18 years - implications for clinical transplantation and stability programs.
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Underwood J, Rahim M, West C, Britton R, Skipworth E, Graves V, Sexton S, Harris H, Schwering D, Sinn A, Pollok KE, Robertson KA, Goebel WS, and Hege KM
- Abstract
Background: Peripheral blood stem cells (PBSC) are commonly cryopreserved awaiting clinical use for hematopoietic stem cell transplant. Long term cryopreservation is commonly defined as five years or longer, and limited data exists regarding how long PBSC can be cryopreserved and retain the ability to successfully engraft. Clinical programs, stem cell banks, and regulatory and accrediting agencies interested in product stability would benefit from such data. Thus, we assessed recovery and colony forming ability of PBSC following long-term cryopreservation as well as their ability to engraft in NOD/SCID/IL-2Rγ
null (NSG) mice., Aim: To investigate the in vivo engraftment potential of long-term cryopreserved PBSC units., Methods: PBSC units which were collected and frozen using validated clinical protocols were obtained for research use from the Cellular Therapy Laboratory at Indiana University Health. These units were thawed in the Cellular Therapy Laboratory using clinical standards of practice, and the pre-freeze and post-thaw characteristics of the units were compared. Progenitor function was assessed using standard colony-forming assays. CD34-selected cells were transplanted into immunodeficient mice to assess stem cell function., Results: Ten PBSC units with mean of 17 years in cryopreservation (range 13.6-18.3 years) demonstrated a mean total cell recovery of 88% ± 12% (range 68%-110%) and post-thaw viability of 69% ± 17% (range 34%-86%). BFU-E growth was shown in 9 of 10 units and CFU-GM growth in 7 of 10 units post-thaw. Immunodeficient mice were transplanted with CD34-selected cells from four randomly chosen PBSC units. All mice demonstrated long-term engraftment at 12 wk with mean 34% ± 24% human CD45+ cells, and differentiation with presence of human CD19+, CD3+ and CD33+ cells. Harvested bone marrow from all mice demonstrated growth of erythroid and myeloid colonies., Conclusion: We demonstrated engraftment of clinically-collected and thawed PBSC following cryopreservation up to 18 years in NSG mice, signifying likely successful clinical transplantation of PBSC following long-term cryopreservation., Competing Interests: Conflict-of-interest statement: Goebel WS receives fees as a consulting medical director for Cook Regentec, LLC, and serves as medical director for Ossium Health, Inc. All other authors report no potential conflicts of interest., (©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.)- Published
- 2020
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22. Metabolic Regulators Nampt and Sirt6 Serially Participate in the Macrophage Interferon Antiviral Cascade.
- Author
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Dantoft W, Robertson KA, Watkins WJ, Strobl B, and Ghazal P
- Abstract
Molecular determinants underlying interferon (IFN)-macrophage biology can help delineate enzyme systems, pathways and mechanisms for enabling host-directed therapeutic approaches against infection. Notably, while the IFN antiviral response is known to be directly coupled to mevalonate-sterol biosynthesis, mechanistic insight for providing host pathway-therapeutic targets remain incomplete. Here, we show that Nampt and Sirt6 are coordinately regulated upon immune activation of macrophages and contribute to the IFN-sterol antiviral response. In silico analysis of the Nampt and Sirt6 promoter regions identified multiple core immune gene-regulatory transcription factor sites, including Stat1, implicating a molecular link to IFN control. Experimentally, we show using a range of genetically IFN-defective macrophages that the expression of Nampt is stringently regulated by the Jak/Stat-pathway while Sirt6 activation is temporally displaced in a partial IFN-dependent manner. We further show that pharmacological inhibition of Nampt and small interfering RNA (siRNA)-mediated inhibition of Nampt and Sirt6 promotes viral growth of cytomegalovirus in both fibroblasts and macrophages. Our results support the notion of pharmacologically exploiting immune regulated enzyme systems of macrophages for use as an adjuvant-based therapy for augmenting host protective pathway responses to infection.
- Published
- 2019
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23. The cholesterol biosynthesis pathway regulates IL-10 expression in human Th1 cells.
- Author
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Perucha E, Melchiotti R, Bibby JA, Wu W, Frederiksen KS, Roberts CA, Hall Z, LeFriec G, Robertson KA, Lavender P, Gerwien JG, Taams LS, Griffin JL, de Rinaldis E, van Baarsen LGM, Kemper C, Ghazal P, and Cope AP
- Subjects
- Atorvastatin pharmacology, Humans, Hydroxycholesterols pharmacology, Th1 Cells drug effects, Cholesterol biosynthesis, Interferon-gamma metabolism, Interleukin-10 metabolism, Th1 Cells metabolism
- Abstract
The mechanisms controlling CD4
+ T cell switching from an effector to an anti-inflammatory (IL-10+ ) phenotype play an important role in the persistence of chronic inflammatory diseases. Here, we identify the cholesterol biosynthesis pathway as a key regulator of this process. Pathway analysis of cultured cytokine-producing human T cells reveals a significant association between IL-10 and cholesterol metabolism gene expression. Inhibition of the cholesterol biosynthesis pathway with atorvastatin or 25-hydroxycholesterol during switching from IFNγ+ to IL-10+ shows a specific block in immune resolution, defined as a significant decrease in IL-10 expression. Mechanistically, the master transcriptional regulator of IL10 in T cells, c-Maf, is significantly decreased by physiological levels of 25-hydroxycholesterol. Strikingly, progression to rheumatoid arthritis is associated with altered expression of cholesterol biosynthesis genes in synovial biopsies of predisposed individuals. Our data reveal a link between sterol metabolism and the regulation of the anti-inflammatory response in human CD4+ T cells.- Published
- 2019
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24. An abnormal bone marrow microenvironment contributes to hematopoietic dysfunction in Fanconi anemia.
- Author
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Zhou Y, He Y, Xing W, Zhang P, Shi H, Chen S, Shi J, Bai J, Rhodes SD, Zhang F, Yuan J, Yang X, Zhu X, Li Y, Hanenberg H, Xu M, Robertson KA, Yuan W, Nalepa G, Cheng T, Clapp DW, and Yang FC
- Subjects
- Animals, Bone and Bones abnormalities, Bone and Bones physiopathology, Cell Lineage, Fanconi Anemia physiopathology, Fanconi Anemia Complementation Group C Protein genetics, Hematopoiesis, Hematopoietic Stem Cell Transplantation, Mesenchymal Stem Cells pathology, Mice, Mice, Knockout, Bone Marrow pathology, Cellular Microenvironment, Fanconi Anemia pathology
- Abstract
Fanconi anemia is a complex heterogeneous genetic disorder with a high incidence of bone marrow failure, clonal evolution to acute myeloid leukemia and mesenchymal-derived congenital anomalies. Increasing evidence in Fanconi anemia and other genetic disorders points towards an interdependence of skeletal and hematopoietic development, yet the impact of the marrow microenvironment in the pathogenesis of the bone marrow failure in Fanconi anemia remains unclear. Here we demonstrated that mice with double knockout of both Fancc and Fancg genes had decreased bone formation at least partially due to impaired osteoblast differentiation from mesenchymal stem/progenitor cells. Mesenchymal stem/progenitor cells from the double knockout mice showed impaired hematopoietic supportive activity. Mesenchymal stem/progenitor cells of patients with Fanconi anemia exhibited similar cellular deficits, including increased senescence, reduced proliferation, impaired osteoblast differentiation and defective hematopoietic stem/progenitor cell supportive activity. Collectively, these studies provide unique insights into the physiological significance of mesenchymal stem/progenitor cells in supporting the marrow microenvironment, which is potentially of broad relevance in hematopoietic stem cell transplantation., (Copyright© Ferrata Storti Foundation.)
- Published
- 2017
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25. Interferon Control of the Sterol Metabolic Network: Bidirectional Molecular Circuitry-Mediating Host Protection.
- Author
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Robertson KA and Ghazal P
- Abstract
The sterol metabolic network is emerging center stage in inflammation and immunity. Historically, observational clinical studies show that hypocholesterolemia is a common side effect of interferon (IFN) treatment. More recently, comprehensive systems-wide investigations of the macrophage IFN response reveal a direct molecular link between cholesterol metabolism and infection. Upon infection, flux through the sterol metabolic network is acutely moderated by the IFN response at multiple regulatory levels. The precise mechanisms by which IFN regulates the mevalonate-sterol pathway-the spine of the network-are beginning to be unraveled. In this review, we discuss our current understanding of the multifactorial mechanisms by which IFN regulates the sterol pathway. We also consider bidirectional communications resulting in sterol metabolism regulation of immunity. Finally, we deliberate on how this fundamental interaction functions as an integral element of host protective responses to infection and harmful inflammation.
- Published
- 2016
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26. Sleep and pulmonary outcomes for clinical trials of airway plexiform neurofibromas in NF1.
- Author
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Plotkin SR, Davis SD, Robertson KA, Akshintala S, Allen J, Fisher MJ, Blakeley JO, Widemann BC, Ferner RE, and Marcus CL
- Subjects
- Humans, Lung physiopathology, Neurofibroma, Plexiform physiopathology, Neurofibromatosis 1 physiopathology, Sleep physiology, Treatment Outcome, Clinical Trials as Topic methods, Neurofibroma, Plexiform therapy, Neurofibromatosis 1 therapy, Oscillometry methods, Polysomnography methods, Spirometry methods
- Abstract
Objective: Plexiform neurofibromas (PNs) are complex, benign nerve sheath tumors that occur in approximately 25%-50% of individuals with neurofibromatosis type 1 (NF1). PNs that cause airway compromise or pulmonary dysfunction are uncommon but clinically important. Because improvement in sleep quality or airway function represents direct clinical benefit, measures of sleep and pulmonary function may be more meaningful than tumor size as endpoints in therapeutic clinical trials targeting airway PN., Methods: The Response Evaluation in Neurofibromatosis and Schwannomatosis functional outcomes group reviewed currently available endpoints for sleep and pulmonary outcomes and developed consensus recommendations for response evaluation in NF clinical trials., Results: For patients with airway PNs, polysomnography, impulse oscillometry, and spirometry should be performed to identify abnormal function that will be targeted by the agent under clinical investigation. The functional group endorsed the use of the apnea hypopnea index (AHI) as the primary sleep endpoint, and pulmonary resistance at 10 Hz (R10) or forced expiratory volume in 1 or 0.75 seconds (FEV1 or FEV0.75) as primary pulmonary endpoints. The group defined minimum changes in AHI, R10, and FEV1 or FEV0.75 for response criteria. Secondary sleep outcomes include desaturation and hypercapnia during sleep and arousal index. Secondary pulmonary outcomes include pulmonary resistance and reactance measurements at 5, 10, and 20 Hz; forced vital capacity; peak expiratory flow; and forced expiratory flows., Conclusions: These recommended sleep and pulmonary evaluations are intended to provide researchers with a standardized set of clinically meaningful endpoints for response evaluation in trials of NF1-related airway PNs., (© 2016 American Academy of Neurology.)
- Published
- 2016
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27. An Interferon Regulated MicroRNA Provides Broad Cell-Intrinsic Antiviral Immunity through Multihit Host-Directed Targeting of the Sterol Pathway.
- Author
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Robertson KA, Hsieh WY, Forster T, Blanc M, Lu H, Crick PJ, Yutuc E, Watterson S, Martin K, Griffiths SJ, Enright AJ, Yamamoto M, Pradeepa MM, Lennox KA, Behlke MA, Talbot S, Haas J, Dölken L, Griffiths WJ, Wang Y, Angulo A, and Ghazal P
- Subjects
- Animals, Mice, Inbred C57BL, Interferon Regulatory Factor-1 metabolism, Interferons physiology, MicroRNAs metabolism, Sterols biosynthesis, Virus Diseases immunology
- Abstract
In invertebrates, small interfering RNAs are at the vanguard of cell-autonomous antiviral immunity. In contrast, antiviral mechanisms initiated by interferon (IFN) signaling predominate in mammals. Whilst mammalian IFN-induced miRNA are known to inhibit specific viruses, it is not known whether host-directed microRNAs, downstream of IFN-signaling, have a role in mediating broad antiviral resistance. By performing an integrative, systematic, global analysis of RNA turnover utilizing 4-thiouridine labeling of newly transcribed RNA and pri/pre-miRNA in IFN-activated macrophages, we identify a new post-transcriptional viral defense mechanism mediated by miR-342-5p. On the basis of ChIP and site-directed promoter mutagenesis experiments, we find the synthesis of miR-342-5p is coupled to the antiviral IFN response via the IFN-induced transcription factor, IRF1. Strikingly, we find miR-342-5p targets mevalonate-sterol biosynthesis using a multihit mechanism suppressing the pathway at different functional levels: transcriptionally via SREBF2, post-transcriptionally via miR-33, and enzymatically via IDI1 and SC4MOL. Mass spectrometry-based lipidomics and enzymatic assays demonstrate the targeting mechanisms reduce intermediate sterol pathway metabolites and total cholesterol in macrophages. These results reveal a previously unrecognized mechanism by which IFN regulates the sterol pathway. The sterol pathway is known to be an integral part of the macrophage IFN antiviral response, and we show that miR-342-5p exerts broad antiviral effects against multiple, unrelated pathogenic viruses such Cytomegalovirus and Influenza A (H1N1). Metabolic rescue experiments confirm the specificity of these effects and demonstrate that unrelated viruses have differential mevalonate and sterol pathway requirements for their replication. This study, therefore, advances the general concept of broad antiviral defense through multihit targeting of a single host pathway.
- Published
- 2016
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28. The SYNERGY biodegradable polymer everolimus eluting coronary stent: Porcine vascular compatibility and polymer safety study.
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Wilson GJ, Marks A, Berg KJ, Eppihimer M, Sushkova N, Hawley SP, Robertson KA, Knapp D, Pennington DE, Chen YL, Foss A, Huibregtse B, and Dawkins KD
- Subjects
- Angioplasty, Balloon, Coronary mortality, Animals, Coated Materials, Biocompatible, Coronary Disease diagnostic imaging, Coronary Disease mortality, Disease Models, Animal, Equipment Failure Analysis, Female, Metals, Prosthesis Design, Prosthesis Failure, Radiography, Random Allocation, Sensitivity and Specificity, Survival Rate, Swine, Absorbable Implants, Angioplasty, Balloon, Coronary methods, Coronary Disease therapy, Drug-Eluting Stents, Everolimus administration & dosage, Polymers chemistry
- Abstract
Aims: SYNERGY is a novel platinum chromium alloy stent that delivers abluminal everolimus from an ultrathin poly-lactide-co-glycide (PLGA) biodegradable polymer. This study evaluated the in vivo degradation of the polymer coating, everolimus release time course, and vascular compatibility of the SYNERGY stent., Methods and Results: SYNERGY stents were implanted in arteries of domestic swine. Devices were explanted at predetermined time points (up to 120 days) and the extent of PLGA coating or everolimus remaining on the stents was quantified. Everolimus levels in the arterial tissue were also evaluated. A pathological analysis on coronary arteries of single and overlapping stents was performed at time points between 5 and 270 days. PLGA bioabsorption began immediately after implantation, and drug release was essentially complete by 90 days; PLGA absorption was substantially complete by 120 days (>90% of polymer was absorbed) leaving a bare metal SYNERGY stent. Vascular response was similar among SYNERGY and control stents (bare metal, polymer-only, and 3× polymer-only). Mild increases in para-strut fibrin were seen for SYNERGY at an early time point with no significant differences in all other morphological and morphometric parameters through 270 days or endothelial function (eNOS immunostaining) at 90 or 180 days. Inflammation was predominantly minimal to mild for all device types., Conclusion: In a swine model, everolimus was released by 90 days and PLGA bioabsorption was complete shortly thereafter. The SYNERGY stent and its biodegradable polymer, even at a 3× safety margin, demonstrated vascular compatibility similar to bare metal stent controls., (© 2015 Wiley Periodicals, Inc.)
- Published
- 2015
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29. Biomarkers for Diagnosis and Prognosis of Sinusoidal Obstruction Syndrome after Hematopoietic Cell Transplantation.
- Author
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Akil A, Zhang Q, Mumaw CL, Raiker N, Yu J, Velez de Mendizabal N, Haneline LS, Robertson KA, Skiles J, Diaz-Ricart M, Carreras E, Renbarger J, Hanash S, Bies RR, and Paczesny S
- Subjects
- Adolescent, Adult, Bayes Theorem, Child, Child, Preschool, Cohort Studies, Female, Hepatic Veno-Occlusive Disease blood, Hepatic Veno-Occlusive Disease mortality, Humans, Intercellular Adhesion Molecule-1 blood, Male, Mass Spectrometry methods, Middle Aged, Prognosis, Proteomics, Risk Assessment, Tissue Inhibitor of Metalloproteinase-1 blood, Young Adult, von Willebrand Factor analysis, Ficolins, Biomarkers blood, Hematopoietic Stem Cell Transplantation adverse effects, Hepatic Veno-Occlusive Disease diagnosis, Hyaluronic Acid blood, Lectins blood, Vascular Cell Adhesion Molecule-1 blood
- Abstract
Reliable, noninvasive methods for diagnosing and prognosing sinusoidal obstruction syndrome (SOS) early after hematopoietic cell transplantation (HCT) are needed. We used a quantitative mass spectrometry-based proteomics approach to identify candidate biomarkers of SOS by comparing plasma pooled from 20 patients with and 20 patients without SOS. Of 494 proteins quantified, we selected 6 proteins (L-Ficolin, vascular cell adhesion molecule-1 [VCAM1], tissue inhibitor of metalloproteinase-1, von Willebrand factor, intercellular adhesion molecule-1, and CD97) based on a differential heavy/light isotope ratio of at least 2 fold, information from the literature, and immunoassay availability. Next, we evaluated the diagnostic potential of these 6 proteins and 5 selected from the literature (suppression of tumorigenicity-2 [ST2], angiopoietin-2 (ANG2), hyaluronic acid [HA], thrombomodulin, and plasminogen activator inhibitor-1) in samples from 80 patients. The results demonstrate that together ST2, ANG2, L-Ficolin, HA, and VCAM1 compose a biomarker panel for diagnosis of SOS. L-Ficolin, HA, and VCAM1 also stratified patients at risk for SOS as early as the day of HCT. Prognostic Bayesian modeling for SOS onset based on L-Ficolin, HA, and VCAM1 levels on the day of HCT and clinical characteristics showed >80% correct prognosis of SOS onset. These biomarkers may provide opportunities for preemptive intervention to minimize SOS incidence and/or severity., (Copyright © 2015 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)
- Published
- 2015
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30. Rapid proteasomal elimination of 3-hydroxy-3-methylglutaryl-CoA reductase by interferon-γ in primary macrophages requires endogenous 25-hydroxycholesterol synthesis.
- Author
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Lu H, Talbot S, Robertson KA, Watterson S, Forster T, Roy D, and Ghazal P
- Subjects
- Activating Transcription Factor 3 genetics, Activating Transcription Factor 3 metabolism, Animals, Bone Marrow Cells cytology, Cells, Cultured, Kinetics, Macrophages drug effects, Mice, Inbred C57BL, Models, Biological, Proteolysis drug effects, Proteomics, RNA biosynthesis, RNA, Messenger genetics, RNA, Messenger metabolism, Steroid Hydroxylases genetics, Steroid Hydroxylases metabolism, Sterol Regulatory Element Binding Protein 1 metabolism, Time Factors, Transcription, Genetic drug effects, Hydroxycholesterols metabolism, Hydroxymethylglutaryl CoA Reductases metabolism, Interferon-gamma pharmacology, Macrophages metabolism, Proteasome Endopeptidase Complex metabolism
- Abstract
Interferons (IFNs) play a central role in immunity and emerging evidence suggests that IFN-signalling coordinately regulates sterol biosynthesis in macrophages, via Sterol Regulatory Element-Binding Protein (SREBP) dependent and independent pathways. However, the precise mechanisms and kinetic steps by which IFN controls sterol biosynthesis are as yet not fully understood. Here, we elucidate the molecular circuitry governing how IFN controls the first regulated step in the mevalonate-sterol pathway, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), through the synthesis of 25-Hydroxycholesterol (25-HC) from cholesterol by the IFN-inducible Cholesterol-25-Hydroxylase (CH25H). We show for the first 30-min of IFN stimulation of macrophages the rate of de novo synthesis of the Ch25h transcript is markedly increased but by 120-min becomes transcriptionally curtailed, coincident with induction of the Activating Transcription Factor 3 (ATF3) repressor. We demonstrate ATF3 induction by Toll-like receptors is strictly dependent on IFN-signalling. While the SREBP-pathway dependent rates of de novo transcription of Hmgcr are relatively unchanged in the first 90-min of IFN treatment, we find HMGCR enzyme levels undergo a rapid proteasomal-mediated degradation, defining a previously unappreciated SREBP-independent mechanism for IFN-action. These events precede a sustained marked reduction in Hmgcr RNA levels involving SREBP-dependent mechanisms. We demonstrate that HMGCR proteasomal-degradation by IFN strictly requires the synthesis of endogenous 25-HC and functionally couples HMGCR to CH25H to coordinately suppress sterol biosynthesis. In conclusion, we quantitatively delineate proteomic and transcriptional levels of IFN-mediated control of HMGCR, the primary enzymatic step of the mevalonate-sterol biosynthesis pathway, providing a foundational framework for mathematically modelling the therapeutic outcome of immune-metabolic pathways., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2015
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31. A model of flux regulation in the cholesterol biosynthesis pathway: Immune mediated graduated flux reduction versus statin-like led stepped flux reduction.
- Author
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Watterson S, Guerriero ML, Blanc M, Mazein A, Loewe L, Robertson KA, Gibbs H, Shui G, Wenk MR, Hillston J, and Ghazal P
- Subjects
- Immunity, Innate drug effects, Interferon-gamma pharmacology, Muromegalovirus physiology, Reproducibility of Results, Cholesterol biosynthesis, Cholesterol metabolism, Hydroxymethylglutaryl-CoA Reductase Inhibitors pharmacology, Immunity drug effects, Models, Biological
- Abstract
The cholesterol biosynthesis pathway has recently been shown to play an important role in the innate immune response to viral infection with host protection occurring through a coordinate down regulation of the enzymes catalysing each metabolic step. In contrast, statin based drugs, which form the principle pharmaceutical agents for decreasing the activity of this pathway, target a single enzyme. Here, we build an ordinary differential equation model of the cholesterol biosynthesis pathway in order to investigate how the two regulatory strategies impact upon the behaviour of the pathway. We employ a modest set of assumptions: that the pathway operates away from saturation, that each metabolite is involved in multiple cellular interactions and that mRNA levels reflect enzyme concentrations. Using data taken from primary bone marrow derived macrophage cells infected with murine cytomegalovirus or treated with IFNγ, we show that, under these assumptions, coordinate down-regulation of enzyme activity imparts a graduated reduction in flux along the pathway. In contrast, modelling a statin-like treatment that achieves the same degree of down-regulation in cholesterol production, we show that this delivers a step change in flux along the pathway. The graduated reduction mediated by physiological coordinate regulation of multiple enzymes supports a mechanism that allows a greater level of specificity, altering cholesterol levels with less impact upon interactions branching from the pathway, than pharmacological step reductions. We argue that coordinate regulation is likely to show a long-term evolutionary advantage over single enzyme regulation. Finally, the results from our models have implications for future pharmaceutical therapies intended to target cholesterol production with greater specificity and fewer off target effects, suggesting that this can be achieved by mimicking the coordinated down-regulation observed in immunological responses., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)
- Published
- 2013
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32. The transcription factor STAT-1 couples macrophage synthesis of 25-hydroxycholesterol to the interferon antiviral response.
- Author
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Blanc M, Hsieh WY, Robertson KA, Kropp KA, Forster T, Shui G, Lacaze P, Watterson S, Griffiths SJ, Spann NJ, Meljon A, Talbot S, Krishnan K, Covey DF, Wenk MR, Craigon M, Ruzsics Z, Haas J, Angulo A, Griffiths WJ, Glass CK, Wang Y, and Ghazal P
- Subjects
- Animals, Binding Sites, Bone Marrow Cells drug effects, Bone Marrow Cells immunology, Bone Marrow Cells metabolism, Bone Marrow Cells virology, Gene Expression Regulation, Hydroxycholesterols pharmacology, Liver X Receptors, Macrophage Activation drug effects, Macrophage Activation immunology, Macrophages drug effects, Macrophages virology, Mevalonic Acid metabolism, Mice, Orphan Nuclear Receptors metabolism, Promoter Regions, Genetic, Protein Binding, Steroid Hydroxylases genetics, Virus Replication drug effects, Antiviral Agents pharmacology, Hydroxycholesterols metabolism, Interferons pharmacology, Macrophages immunology, Macrophages metabolism, STAT1 Transcription Factor metabolism
- Abstract
Recent studies suggest that the sterol metabolic network participates in the interferon (IFN) antiviral response. However, the molecular mechanisms linking IFN with the sterol network and the identity of sterol mediators remain unknown. Here we report a cellular antiviral role for macrophage production of 25-hydroxycholesterol (cholest-5-en-3β,25-diol, 25HC) as a component of the sterol metabolic network linked to the IFN response via Stat1. By utilizing quantitative metabolome profiling of all naturally occurring oxysterols upon infection or IFN-stimulation, we reveal 25HC as the only macrophage-synthesized and -secreted oxysterol. We show that 25HC can act at multiple levels as a potent paracrine inhibitor of viral infection for a broad range of viruses. We also demonstrate, using transcriptional regulatory-network analyses, genetic interventions and chromatin immunoprecipitation experiments that Stat1 directly coupled Ch25h regulation to IFN in macrophages. Our studies describe a physiological role for 25HC as a sterol-lipid effector of an innate immune pathway., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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33. Imatinib mesylate for plexiform neurofibromas in patients with neurofibromatosis type 1: a phase 2 trial.
- Author
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Robertson KA, Nalepa G, Yang FC, Bowers DC, Ho CY, Hutchins GD, Croop JM, Vik TA, Denne SC, Parada LF, Hingtgen CM, Walsh LE, Yu M, Pradhan KR, Edwards-Brown MK, Cohen MD, Fletcher JW, Travers JB, Staser KW, Lee MW, Sherman MR, Davis CJ, Miller LC, Ingram DA, and Clapp DW
- Subjects
- Adolescent, Adult, Benzamides, Child, Child, Preschool, Female, Humans, Imatinib Mesylate, Magnetic Resonance Imaging, Male, Middle Aged, Neurofibroma, Plexiform complications, Neurofibroma, Plexiform pathology, Young Adult, Antineoplastic Agents therapeutic use, Neurofibroma, Plexiform drug therapy, Neurofibromatosis 1 complications, Piperazines therapeutic use, Protein Kinase Inhibitors therapeutic use, Pyrimidines therapeutic use
- Abstract
Background: Plexiform neurofibromas are slow-growing chemoradiotherapy-resistant tumours arising in patients with neurofibromatosis type 1 (NF1). Currently, there are no viable therapeutic options for patients with plexiform neurofibromas that cannot be surgically removed because of their proximity to vital body structures. We undertook an open-label phase 2 trial to test whether treatment with imatinib mesylate can decrease the volume burden of clinically significant plexiform neurofibromas in patients with NF1., Methods: Eligible patients had to be aged 3-65 years, and to have NF1 and a clinically significant plexiform neurofibroma. Patients were treated with daily oral imatinib mesylate at 220 mg/m(2) twice a day for children and 400 mg twice a day for adults for 6 months. The primary endpoint was a 20% or more reduction in plexiform size by sequential volumetric MRI imaging. Clinical data were analysed on an intention-to-treat basis; a secondary analysis was also done for those patients able to take imatinib mesylate for 6 months. This trial is registered with ClinicalTrials.gov, number NCT01673009., Findings: Six of 36 patients (17%, 95% CI 6-33), enrolled on an intention-to-treat basis, had an objective response to imatinib mesylate, with a 20% or more decrease in tumour volume. Of the 23 patients who received imatinib mesylate for at least 6 months, six (26%, 95% CI 10-48) had a 20% or more decrease in volume of one or more plexiform tumours. The most common adverse events were skin rash (five patients) and oedema with weight gain (six). More serious adverse events included reversible grade 3 neutropenia (two), grade 4 hyperglycaemia (one), and grade 4 increases in aminotransferase concentrations (one)., Interpretation: Imatinib mesylate could be used to treat plexiform neurofibromas in patients with NF1. A multi-institutional clinical trial is warranted to confirm these results., Funding: Novartis Pharmaceuticals, the Indiana University Simon Cancer Centre, and the Indiana University Herman B Wells Center for Pediatric Research., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
- Published
- 2012
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34. Marrow signal changes observed in follow-up whole-body MRI studies in children and young adults with neurofibromatosis type 1 treated with imatinib mesylate (Gleevec) for plexiform neurofibromas.
- Author
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Karmazyn B, Cohen MD, Jennings SG, and Robertson KA
- Subjects
- Adolescent, Adult, Antineoplastic Agents therapeutic use, Benzamides, Bone Marrow drug effects, Child, Child, Preschool, Female, Humans, Imatinib Mesylate, Magnetic Resonance Imaging instrumentation, Male, Neurofibroma, Plexiform etiology, Neurofibromatosis 1 complications, Pilot Projects, Treatment Outcome, Whole Body Imaging methods, Young Adult, Bone Marrow pathology, Neurofibroma, Plexiform drug therapy, Neurofibroma, Plexiform pathology, Neurofibromatosis 1 drug therapy, Neurofibromatosis 1 pathology, Piperazines therapeutic use, Pyrimidines therapeutic use
- Abstract
Background: We observed bone marrow signal changes (BMSC) in patients with plexiform neurofibromas after treatment with imatinib mesylate (Gleevec)., Objective: To evaluate the pattern and natural history of BMSC., Materials and Methods: The data were obtained from a pilot study of imatinib mesylate in patients with plexiform neurofibromas. All patients underwent baseline and sequential whole-body STIR 1.5-T MRI after treatment. The bone marrow signal on MRI was evaluated for abnormalities, location and pattern, and any change on follow-up studies., Results: The study group included 16 patients (8 males) with a median age of 14 years (range 4 to 25 years). The mean whole-body MRI follow-up duration was 1.9 years. Of the 16 patients, 14 (88%) developed BMSC. The signal change was asymmetrical in 9 of the 14 patients (64%). The appendicular skeleton was involved in all 14 patients and the axial skeleton in 3 patients (21%). BMSC was followed in 13 patients and decreased signal was seen in 9 patients (69%) after a mean duration of 1.3 years of treatment (range 0.6 to 2.9 years); no complications were observed., Conclusion: BMSC appeared in most patients with neurofibromatosis type 1 following treatment with imatinib mesylate. BMSC was unusually asymmetrical and involved the lower extremities. On follow-up, BMSC often showed a decrease without complications.
- Published
- 2012
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35. Extending signaling pathways with protein-interaction networks. Application to apoptosis.
- Author
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Planas-Iglesias J, Guney E, García-García J, Robertson KA, Raza S, Freeman TC, Ghazal P, and Oliva B
- Subjects
- Computational Biology methods, Humans, Models, Biological, Apoptosis physiology, Protein Interaction Maps physiology, Signal Transduction physiology
- Abstract
Cells exploit signaling pathways during responses to environmental changes, and these processes are often modulated during disease. Particularly, relevant human pathologies such as cancer or viral infections require downregulating apoptosis signaling pathways to progress. As a result, the identification of proteins responsible for these changes is essential for the diagnostics and development of therapeutics. Transferring functional annotation within protein interaction networks has proven useful to identify such proteins, although this is not a trivial task. Here, we used different scoring methods to transfer annotation from 53 well-studied members of the human apoptosis pathways (as known by 2005) to their protein interactors. All scoring methods produced significant predictions (compared to a random negative model), but its number was too large to be useful. Thus, we made a final prediction using specific combinations of scoring methods and compared it to the proteins related to apoptosis signaling pathways during the last 5 years. We propose 273 candidate proteins that may be relevant in apoptosis signaling pathways. Although some of them have known functions consistent with their proposed apoptotsis involvement, the majority have not been annotated yet, leaving room for further experimental studies. We provide our predictions at http://sbi.imim.es/web/Apoptosis.php.
- Published
- 2012
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36. Atomic radiations in the decay of medical radioisotopes: a physics perspective.
- Author
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Lee BQ, Kibédi T, Stuchbery AE, and Robertson KA
- Subjects
- DNA chemistry, Humans, Kinetics, Models, Theoretical, Radiation Dosage, Radiation Oncology methods, Electrons, Iodine Radioisotopes pharmacology, Neoplasms radiotherapy, Physics methods, Radioactivity, Radioisotopes therapeutic use
- Abstract
Auger electrons emitted in nuclear decay offer a unique tool to treat cancer cells at the scale of a DNA molecule. Over the last forty years many aspects of this promising research goal have been explored, however it is still not in the phase of serious clinical trials. In this paper, we review the physical processes of Auger emission in nuclear decay and present a new model being developed to evaluate the energy spectrum of Auger electrons, and hence overcome the limitations of existing computations.
- Published
- 2012
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37. Reversible inhibition of murine cytomegalovirus replication by gamma interferon (IFN-γ) in primary macrophages involves a primed type I IFN-signaling subnetwork for full establishment of an immediate-early antiviral state.
- Author
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Kropp KA, Robertson KA, Sing G, Rodriguez-Martin S, Blanc M, Lacaze P, Hassim MF, Khondoker MR, Busche A, Dickinson P, Forster T, Strobl B, Mueller M, Jonjic S, Angulo A, and Ghazal P
- Subjects
- Animals, Macrophage Activation, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Signal Transduction, Time Factors, Interferon Type I immunology, Interferon-gamma immunology, Macrophages immunology, Macrophages virology, Muromegalovirus growth & development, Muromegalovirus immunology
- Abstract
Activated macrophages play a central role in controlling inflammatory responses to infection and are tightly regulated to rapidly mount responses to infectious challenge. Type I interferon (alpha/beta interferon [IFN-α/β]) and type II interferon (IFN-γ) play a crucial role in activating macrophages and subsequently restricting viral infections. Both types of IFNs signal through related but distinct signaling pathways, inducing a vast number of interferon-stimulated genes that are overlapping but distinguishable. The exact mechanism by which IFNs, particularly IFN-γ, inhibit DNA viruses such as cytomegalovirus (CMV) is still not fully understood. Here, we investigate the antiviral state developed in macrophages upon reversible inhibition of murine CMV by IFN-γ. On the basis of molecular profiling of the reversible inhibition, we identify a significant contribution of a restricted type I IFN subnetwork linked with IFN-γ activation. Genetic knockout of the type I-signaling pathway, in the context of IFN-γ stimulation, revealed an essential requirement for a primed type I-signaling process in developing a full refractory state in macrophages. A minimal transient induction of IFN-β upon macrophage activation with IFN-γ is also detectable. In dose and kinetic viral replication inhibition experiments with IFN-γ, the establishment of an antiviral effect is demonstrated to occur within the first hours of infection. We show that the inhibitory mechanisms at these very early times involve a blockade of the viral major immediate-early promoter activity. Altogether our results show that a primed type I IFN subnetwork contributes to an immediate-early antiviral state induced by type II IFN activation of macrophages, with a potential further amplification loop contributed by transient induction of IFN-β.
- Published
- 2011
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38. Host defense against viral infection involves interferon mediated down-regulation of sterol biosynthesis.
- Author
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Blanc M, Hsieh WY, Robertson KA, Watterson S, Shui G, Lacaze P, Khondoker M, Dickinson P, Sing G, Rodríguez-Martín S, Phelan P, Forster T, Strobl B, Müller M, Riemersma R, Osborne T, Wenk MR, Angulo A, and Ghazal P
- Subjects
- Animals, Antiviral Agents pharmacology, Cholesterol metabolism, Herpesviridae Infections metabolism, Hydroxymethylglutaryl-CoA Reductase Inhibitors pharmacology, Immunity, Innate, Interferon-beta biosynthesis, Interferon-beta pharmacology, Interferon-gamma biosynthesis, Interferon-gamma pharmacology, Macrophages immunology, Macrophages metabolism, Macrophages virology, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, NIH 3T3 Cells, RNA Interference, Signal Transduction, Simvastatin pharmacology, Sterol Regulatory Element Binding Protein 2 physiology, Down-Regulation, Herpesviridae Infections immunology, Interferon-beta physiology, Interferon-gamma physiology, Muromegalovirus immunology, Sterols biosynthesis
- Abstract
Little is known about the protective role of inflammatory processes in modulating lipid metabolism in infection. Here we report an intimate link between the innate immune response to infection and regulation of the sterol metabolic network characterized by down-regulation of sterol biosynthesis by an interferon regulatory loop mechanism. In time-series experiments profiling genome-wide lipid-associated gene expression of macrophages, we show a selective and coordinated negative regulation of the complete sterol pathway upon viral infection or cytokine treatment with IFNγ or β but not TNF, IL1β, or IL6. Quantitative analysis at the protein level of selected sterol metabolic enzymes upon infection shows a similar level of suppression. Experimental testing of sterol metabolite levels using lipidomic-based measurements shows a reduction in metabolic output. On the basis of pharmacologic and RNAi inhibition of the sterol pathway we show augmented protection against viral infection, and in combination with metabolite rescue experiments, we identify the requirement of the mevalonate-isoprenoid branch of the sterol metabolic network in the protective response upon statin or IFNβ treatment. Conditioned media experiments from infected cells support an involvement of secreted type 1 interferon(s) to be sufficient for reducing the sterol pathway upon infection. Moreover, we show that infection of primary macrophages containing a genetic knockout of the major type I interferon, IFNβ, leads to only a partial suppression of the sterol pathway, while genetic knockout of the receptor for all type I interferon family members, ifnar1, or associated signaling component, tyk2, completely abolishes the reduction of the sterol biosynthetic activity upon infection. Levels of the proteolytically cleaved nuclear forms of SREBP2, a key transcriptional regulator of sterol biosynthesis, are reduced upon infection and IFNβ treatment at both the protein and de novo transcription level. The reduction in srebf2 gene transcription upon infection and IFN treatment is also found to be strictly dependent on ifnar1. Altogether these results show that type 1 IFN signaling is both necessary and sufficient for reducing the sterol metabolic network activity upon infection, thereby linking the regulation of the sterol pathway with interferon anti-viral defense responses. These findings bring a new link between sterol metabolism and interferon antiviral response and support the idea of using host metabolic modifiers of innate immunity as a potential antiviral strategy., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2011
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39. Inhibition of the redox function of APE1/Ref-1 in myeloid leukemia cell lines results in a hypersensitive response to retinoic acid-induced differentiation and apoptosis.
- Author
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Fishel ML, Colvin ES, Luo M, Kelley MR, and Robertson KA
- Subjects
- Benzoquinones pharmacology, Cell Differentiation drug effects, Cell Line, Tumor, Cell Proliferation drug effects, DNA-(Apurinic or Apyrimidinic Site) Lyase physiology, Humans, Leukemia, Myeloid pathology, Oxidation-Reduction, Propionates pharmacology, Receptors, CXCR5 analysis, Receptors, Retinoic Acid metabolism, Response Elements, Retinoic Acid Receptor alpha, Apoptosis drug effects, DNA-(Apurinic or Apyrimidinic Site) Lyase antagonists & inhibitors, Leukemia, Myeloid drug therapy, Tretinoin pharmacology
- Abstract
Objective: The standard of care for promyelocytic leukemia includes use of the differentiating agent all-trans retinoic acid (RA) and chemotherapy. RA induces cell differentiation through retinoic acid receptor (RAR) transcription factors. Because redox mechanisms influence how readily transcription factors bind to DNA response elements (RARE), the impact of small molecule (E3330) inhibition of the redox regulatory protein, apurinic-apyrimidinic endonuclease/redox effector factor (APE1/Ref-1) on RAR DNA binding and function in RA-induced myeloid leukemia cell differentiation and apoptosis was investigated., Materials and Methods: The redox function of APE1 was studied using the small molecule inhibitor E3330 in HL-60 and PLB acute myeloid leukemia cells. Electrophoretic mobility shift assays were employed to determine effect of inhibitor on APE1/Ref-1 redox signaling function. Trypan blue assays, Annexin-V/propidium iodide and CD11b staining, and real-time polymerase chain reaction analyses were employed to determine survival, apoptosis, and differentiation status of cells in culture., Results: RARα binds to its RARE in a redox-dependent manner mediated by APE1/Ref-1 redox regulation. Redox-dependent RAR-RARE binding is blocked by E3330, a small molecule redox inhibitor of APE1/Ref-1. Combination treatment of RA + E3330 results in a profound hypersensitivity of myeloid leukemia cells to RA-induced differentiation and apoptosis. Additionally, redox inhibition by E3330 results in enhanced RAR target gene, BLR-1, expression in myeloid leukemia cells., Conclusions: The redox function of APE1/Ref-1 regulates RAR binding to its DNA RAREs influencing the response of myeloid leukemia cells to RA-induced differentiation. Targeting of APE1/Ref-1 redox function may allow manipulation of the retinoid response with therapeutic implications., (Copyright © 2010 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
40. Species selection maintains self-incompatibility.
- Author
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Goldberg EE, Kohn JR, Lande R, Robertson KA, Smith SA, and Igić B
- Subjects
- Biological Evolution, Genetic Variation, Inbreeding, Phylogeny, Solanaceae classification, Solanaceae genetics, Fertilization physiology, Genetic Speciation, Selection, Genetic, Solanaceae physiology
- Abstract
Identifying traits that affect rates of speciation and extinction and, hence, explain differences in species diversity among clades is a major goal of evolutionary biology. Detecting such traits is especially difficult when they undergo frequent transitions between states. Self-incompatibility, the ability of hermaphrodites to enforce outcrossing, is frequently lost in flowering plants, enabling self-fertilization. We show, however, that in the nightshade plant family (Solanaceae), species with functional self-incompatibility diversify at a significantly higher rate than those without it. The apparent short-term advantages of potentially self-fertilizing individuals are therefore offset by strong species selection, which favors obligate outcrossing.
- Published
- 2010
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- View/download PDF
41. Long-term disease-free survival after nonmyeloablative cyclophosphamide/fludarabine conditioning and related/unrelated allotransplantation for acute myeloid leukemia/myelodysplasia.
- Author
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Nelson RP Jr, Yu M, Schwartz JE, Robertson MJ, Hromas R, Fausel CA, Vance GH, Dlouhy SR, Baute JA, Cox EA, Wood LL, Srivastava S, Robertson KA, Haut PR, Farag SS, Abonour R, Cornetta K, and Cripe LD
- Subjects
- Adolescent, Adult, Age Factors, Aged, Cyclophosphamide therapeutic use, Disease-Free Survival, Female, Follow-Up Studies, Graft vs Host Disease drug therapy, Graft vs Host Disease prevention & control, Hematopoietic Stem Cell Transplantation adverse effects, Hematopoietic Stem Cell Transplantation mortality, Humans, Male, Middle Aged, Survival Analysis, Transplantation, Homologous, Vidarabine analogs & derivatives, Vidarabine therapeutic use, Young Adult, Hematopoietic Stem Cell Transplantation methods, Leukemia, Myeloid, Acute therapy, Myelodysplastic Syndromes therapy, Transplantation Conditioning methods
- Abstract
A total of 50 consecutive patients (median age, 57.5 years) with AML (n=30) or myelodysplasia (MDS, n=20) underwent HLA matched related donor (MRD, n=27) or unrelated donor (MUD, n=23) peripheral blood hematopoietic cell transplantation after nonmyeloablative CY/fludarabine (Flu) conditioning. GVHD prophylaxis included CsA (n=19)+/-mycophenolate mofetil (n=31). At a median follow-up of 59 months, 21 patients (42%) were alive without evidence of disease. By Kaplan-Meier analysis, year 1-4 disease-free survival (DFS) and OS estimates were 0.50/0.58, 0.40/0.46, 0.37/0.43 and 0.37/0.41. MUD recipients were engrafted quickly (13.5 days) compared to MRD recipients (16 days) and relapsed/progressed less frequently (P=0.005). Overall grade 3/4 acute GVHD (aGVHD) occurred in 26% in the absence of antecedent mucositis and was associated with chronic GVHD (cGVHD) and poor OS. Extensive cGVHD developed in 51.2% of 100 day survivors. Rates of aGVHD, cGVHD and survival were similar between MRD and MUD recipients. Of 14 survivors with cGVHD, 5 (35.7%) experienced resolution off immunosuppression, suggesting that tolerance with HLA matched grafts is possible at an advanced age by this method. This study provides further evidence for prolonged DFS after CY/Flu MRD allotransplantation for AML/MDS, and extends the findings to older patients and those with unrelated donors.
- Published
- 2010
- Full Text
- View/download PDF
42. Poly[(mu6-rac-cis-cyclohexane-1,2-dicarboxylato)strontium].
- Author
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Robertson KA and Harrison WT
- Abstract
In the title layered coordination polymer, [Sr(C(8)H(10)O(4))](n), the strontium ion adopts a distorted square-antiprismatic SrO(8) geometry, arising from its coordination by six different cis-cyclohexane-1,2-dicarboxylate dianions (two bidentate and four monodentate). Within the dianion, the cyclohexane ring adopts a chair conformation and the dihedral angle between the planes of the -CO(2)(-) groups is 80.4 (6) degrees. The polyhedral linkage pattern leads to (100) sheets in the crystal in which the SrO(8) groups share triangular faces and edges in which the Sr...Sr topological connectivity is a 6(3) net. The crystal studied was a nonmerohedral twin, with the components related by a 180 degree rotation about [100].
- Published
- 2010
- Full Text
- View/download PDF
43. Accommodating natural and sexual selection in butterfly wing pattern evolution.
- Author
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Oliver JC, Robertson KA, and Monteiro A
- Subjects
- Animal Communication, Animals, Butterflies anatomy & histology, Color, Female, Male, Sex Characteristics, Butterflies physiology, Mating Preference, Animal, Phylogeny, Wings, Animal anatomy & histology
- Abstract
Visual patterns in animals may serve different functions, such as attracting mates and deceiving predators. If a signal is used for multiple functions, the opportunity arises for conflict among the different functions, preventing optimization for any one visual signal. Here we investigate the hypothesis that spatial separation of different visual signal functions has occurred in Bicyclus butterflies. Using phylogenetic reconstructions of character evolution and comparisons of evolutionary rates, we found dorsal surface characters to evolve at higher rates than ventral characters. Dorsal characters also displayed sex-based differences in evolutionary rates more often than did ventral characters. Thus, dorsal characters corresponded to our predictions of mate signalling while ventral characters appear to play an important role in predator avoidance. Forewing characters also fit a model of mate signalling, and displayed higher rates of evolution than hindwing characters. Our results, as well as the behavioural and developmental data from previous studies of Bicyclus species, support the hypothesis that spatial separation of visual signal functions has occurred in Bicyclus butterflies. This study is the first to demonstrate, in a phylogenetic framework, that spatial separation of signals used for mate signalling and those used for predator avoidance is a viable strategy to accommodate multiple signal functions. This signalling strategy has important ramifications on the developmental evolution of wing pattern elements and diversification of butterfly species.
- Published
- 2009
- Full Text
- View/download PDF
44. Unrelated cord blood transplantation for severe congenital neutropenia: report of two cases with very different transplant courses.
- Author
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Markel MK, Haut PR, Renbarger JA, Robertson KA, and Goebel WS
- Subjects
- Graft Rejection, Graft Survival, Graft vs Host Disease, Herpesvirus 6, Human metabolism, Humans, Immune System, Immunosuppressive Agents therapeutic use, Infant, Newborn, Leukemia prevention & control, Male, Neutropenia congenital, Syndrome, Cord Blood Stem Cell Transplantation methods, Fetal Blood metabolism, Neutropenia blood, Transplantation Conditioning methods
- Abstract
SCN is characterized by neutropenia, life-threatening infections, and progression to myelodysplastic syndrome/acute myelogenous leukemia. The only curative option is SCT, but few reports using UCB as a stem cell source exist. Here, we report two SCN patients transplanted with UCB. Patient 1 was transplanted at seven yr of age due to increasingly large injections of G-CSF (>100 microg/kg/day) and the risk of developing leukemia. He engrafted promptly and is clinically well and immune reconstituted >2 yr post-transplant. Patient 2 underwent UCB SCT at nine months of age for recurrent severe infections, despite high doses of G-CSF. He rejected his first graft, having 100% host cells on day +35, and immediately underwent a second UCB SCT. He engrafted but experienced late graft rejection six months after the second transplant. He received a third UCB SCT following a more immunosuppressive conditioning regimen. His course was complicated by HHV-6 viremia and gut GVHD, but he is now clinically well and has 99% donor engraftment >20 months post-transplant. We conclude that UCB is an acceptable stem cell source for SCN patients, but conditioning must be adequately immunosuppressive to ensure engraftment in patients without prior chemotherapy.
- Published
- 2008
- Full Text
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45. Rheumatic heart disease: social and economic dimensions.
- Author
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Robertson KA and Mayosi BM
- Subjects
- Humans, Rheumatic Heart Disease therapy, Socioeconomic Factors, South Africa epidemiology, Cost of Illness, Developed Countries statistics & numerical data, Rheumatic Heart Disease economics, Rheumatic Heart Disease epidemiology
- Published
- 2008
46. A logic-based diagram of signalling pathways central to macrophage activation.
- Author
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Raza S, Robertson KA, Lacaze PA, Page D, Enright AJ, Ghazal P, and Freeman TC
- Subjects
- Animals, Audiovisual Aids, Bone Marrow, Cells, Cultured, Computer Graphics, Immunity, Innate physiology, Interferons metabolism, Logic, Male, Mice, Mice, Inbred BALB C, Monocytes immunology, NF-kappa B metabolism, Protein Interaction Mapping methods, Systems Integration, Toll-Like Receptors metabolism, p38 Mitogen-Activated Protein Kinases immunology, p38 Mitogen-Activated Protein Kinases metabolism, Macrophage Activation physiology, Models, Biological, Signal Transduction immunology, Systems Biology methods
- Abstract
Background: The complex yet flexible cellular response to pathogens is orchestrated by the interaction of multiple signalling and metabolic pathways. The molecular regulation of this response has been studied in great detail but comprehensive and unambiguous diagrams describing these events are generally unavailable. Four key signalling cascades triggered early-on in the innate immune response are the toll-like receptor, interferon, NF-kappaB and apoptotic pathways, which co-operate to defend cells against a given pathogen. However, these pathways are commonly viewed as separate entities rather than an integrated network of molecular interactions., Results: Here we describe the construction of a logically represented pathway diagram which attempts to integrate these four pathways central to innate immunity using a modified version of the Edinburgh Pathway Notation. The pathway map is available in a number of electronic formats and editing is supported by yEd graph editor software., Conclusion: The map presents a powerful visual aid for interpreting the available pathway interaction knowledge and underscores the valuable contribution well constructed pathway diagrams make to communicating large amounts of molecular interaction data. Furthermore, we discuss issues with the limitations and scalability of pathways presented in this fashion, explore options for automated layout of large pathway networks and demonstrate how such maps can aid the interpretation of functional studies.
- Published
- 2008
- Full Text
- View/download PDF
47. Discrete clusters of virus-encoded micrornas are associated with complementary strands of the genome and the 7.2-kilobase stable intron in murine cytomegalovirus.
- Author
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Buck AH, Santoyo-Lopez J, Robertson KA, Kumar DS, Reczko M, and Ghazal P
- Subjects
- Animals, Base Sequence, Bone Marrow Cells, Cells, Cultured, Cloning, Molecular, Computational Biology methods, Fibroblasts virology, L Cells, Male, Mice, Mice, Inbred BALB C, MicroRNAs analysis, MicroRNAs isolation & purification, Molecular Sequence Data, NIH 3T3 Cells virology, RNA, Viral analysis, RNA, Viral genetics, RNA, Viral isolation & purification, Genome, Viral, Introns genetics, Macrophages virology, MicroRNAs genetics, Muromegalovirus genetics, RNA, Complementary genetics
- Abstract
The prevalence and importance of microRNAs (miRNAs) in viral infection are increasingly relevant. Eleven miRNAs were previously identified in human cytomegalovirus (HCMV); however, miRNA content in murine CMV (MCMV), which serves as an important in vivo model for CMV infection, has not previously been examined. We have cloned and characterized 17 novel miRNAs that originate from at least 12 precursor miRNAs in MCMV and are not homologous to HCMV miRNAs. In parallel, we applied a computational analysis, using a support vector machine approach, to identify potential precursor miRNAs in MCMV. Four of the top 10 predicted precursor sequences were cloned in this study, and the combination of computational and cloning analysis demonstrates that MCMV has the capacity to encode miRNAs clustered throughout the genome. On the basis of drug sensitivity experiments for resolving the kinetic class of expression, we show that the MCMV miRNAs are both early and late gene products. Notably, the MCMV miRNAs occur on complementary strands of the genome in specific regions, a feature which has not previously been observed for viral miRNAs. One cluster of miRNAs occurs in close proximity to the 5' splice site of the previously identified 7.2-kb stable intron, implying a variety of potential regulatory mechanisms for MCMV miRNAs.
- Published
- 2007
- Full Text
- View/download PDF
48. Studies of self-incompatibility in wild tomatoes: I. S-allele diversity in Solanum chilense (Dun.) Reiche [corrected] (Solanaceae).
- Author
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Igic B, Smith WA, Robertson KA, Schaal BA, and Kohn JR
- Subjects
- Alleles, Genetic Variation, Pollination genetics, Solanum genetics
- Abstract
We characterized the molecular allelic variation of RNases at the self-incompatibility (SI) locus of Solanum chilense Dun. We recovered 30 S-RNase allele sequences from 34 plants representing a broad geographic sample. This yielded a species-wide estimate of 35 (95% likelihood interval 31-40) S-alleles. We performed crosses to confirm the association with SI function of 10 of the putative S-RNase allele sequences. Results in all cases were consistent with the expectation that these sequences represent functional alleles under single-locus gametophytic SI. We used the allele sequences to conduct an analysis of selection, as measured by the excess of nonsynonymous changes per site, and found evidence for adaptive changes both within the traditionally defined hypervariable regions and downstream, near the 3'-end of the molecule.
- Published
- 2007
- Full Text
- View/download PDF
49. Differential proteomics analysis of synaptic proteins identifies potential cellular targets and protein mediators of synaptic neuroprotection conferred by the slow Wallerian degeneration (Wlds) gene.
- Author
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Wishart TM, Paterson JM, Short DM, Meredith S, Robertson KA, Sutherland C, Cousin MA, Dutia MB, and Gillingwater TH
- Subjects
- Animals, Female, Mice, Mice, Inbred C57BL, Nerve Tissue Proteins genetics, Proteomics, Mitochondrial Proteins metabolism, Nerve Tissue Proteins metabolism, Synapses metabolism, Wallerian Degeneration metabolism
- Abstract
Non-somatic synaptic and axonal compartments of neurons are primary pathological targets in many neurodegenerative conditions, ranging from Alzheimer disease through to motor neuron disease. Axons and synapses are protected from degeneration by the slow Wallerian degeneration (Wld(s)) gene. Significantly the molecular mechanisms through which this spontaneous genetic mutation delays degeneration remain controversial, and the downstream protein targets of Wld(s) resident in non-somatic compartments remain unknown. In this study we used differential proteomics analysis to identify proteins whose expression levels were significantly altered in isolated synaptic preparations from the striatum of Wld(s) mice. Eight of the 16 proteins we identified as having modified expression levels in Wld(s) synapses are known regulators of mitochondrial stability and degeneration (including VDAC1, Aralar1, and mitofilin). Subsequent analyses demonstrated that other key mitochondrial proteins, not identified in our initial screen, are also modified in Wld(s) synapses. Of the non-mitochondrial proteins identified, several have been implicated in neurodegenerative diseases where synapses and axons are primary pathological targets (including DRP-2 and Rab GDP dissociation inhibitor beta). In addition, we show that downstream protein changes can be identified in pathways corresponding to both Ube4b (including UBE1) and Nmnat1 (including VDAC1 and Aralar1) components of the chimeric Wld(s) gene, suggesting that full-length Wld(s) protein is required to elicit maximal changes in synaptic proteins. We conclude that altered mitochondrial responses to degenerative stimuli are likely to play an important role in the neuroprotective Wld(s) phenotype and that targeting proteins identified in the current study may lead to novel therapies for the treatment of neurodegenerative diseases in humans.
- Published
- 2007
- Full Text
- View/download PDF
50. CSK controls retinoic acid receptor (RAR) signaling: a RAR-c-SRC signaling axis is required for neuritogenic differentiation.
- Author
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Dey N, De PK, Wang M, Zhang H, Dobrota EA, Robertson KA, and Durden DL
- Subjects
- Animals, Antineoplastic Agents metabolism, Cell Line, Enzyme Inhibitors metabolism, Humans, Protein-Tyrosine Kinases genetics, Proto-Oncogene Proteins pp60(c-src) genetics, Pyrazoles metabolism, Pyrimidines metabolism, Receptors, Retinoic Acid genetics, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Retinoic Acid Receptor alpha, Tretinoin metabolism, rac1 GTP-Binding Protein metabolism, Cell Differentiation physiology, Genes, src, Neurites physiology, Protein-Tyrosine Kinases metabolism, Proto-Oncogene Proteins pp60(c-src) metabolism, Receptors, Retinoic Acid metabolism, Signal Transduction physiology
- Abstract
Herein, we report the first evidence that c-SRC is required for retinoic acid (RA) receptor (RAR) signaling, an observation that suggests a new paradigm for this family of nuclear hormone receptors. We observed that CSK negatively regulates RAR functions required for neuritogenic differentiation. CSK overexpression inhibited RA-mediated neurite outgrowth, a result which correlated with the inhibition of the SFK c-SRC. Consistent with an extranuclear effect of CSK on RAR signaling and neurite outgrowth, CSK overexpression blocked the downstream activation of RAC1. The conversion of GDP-RAC1 to GTP-RAC1 parallels the activation of c-SRC as early as 15 min following all-trans-retinoic acid treatment in LA-N-5 cells. The cytoplasmic colocalization of c-SRC and RARgamma was confirmed by immunofluorescence staining and confocal microscopy. A direct and ligand-dependent binding of RAR with SRC was observed by surface plasmon resonance, and coimmunoprecipitation studies confirmed the in vivo binding of RARgamma to c-SRC. Deletion of a proline-rich domain within RARgamma abrogated this interaction in vivo. CSK blocked the RAR-RA-dependent activation of SRC and neurite outgrowth in LA-N-5 cells. The results suggest that transcriptional signaling events mediated by RA-RAR are necessary but not sufficient to mediate complex differentiation in neuronal cells. We have elucidated a nongenomic extranuclear signal mediated by the RAR-SRC interaction that is negatively regulated by CSK and is required for RA-induced neuronal differentiation.
- Published
- 2007
- Full Text
- View/download PDF
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