13 results on '"Stephanie O. Omokaro"'
Search Results
2. Standardisation of diet and exercise in clinical trials of NAFLD-NASH: Recommendations from the Liver Forum
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Sven Francque, Manal F. Abdelmalek, Veronica Miller, Claudia Filozof, Elmer Schabel, Katherine Barradas, Mazen Noureddin, Mark Berner-Hansen, Jörn M. Schattenberg, Stephanie O Omokaro, Oliver Glass, and Liver Forum Stand Care Working Grp
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Adult ,0301 basic medicine ,medicine.medical_specialty ,Standard of care ,Context (language use) ,Disease ,Body Mass Index ,Disease activity ,03 medical and health sciences ,0302 clinical medicine ,Lifestyle modification ,Non-alcoholic Fatty Liver Disease ,Humans ,Medicine ,Intensive care medicine ,Exercise ,Clinical Trials as Topic ,Hepatology ,business.industry ,Body Weight ,Fatty liver ,medicine.disease ,Exercise Therapy ,Clinical trial ,Treatment Outcome ,030104 developmental biology ,030211 gastroenterology & hepatology ,Human medicine ,Diet, Healthy ,Waist Circumference ,Steatohepatitis ,business - Abstract
Lifestyle modification is the foundation of treatment recommendations for non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). The design of clinical trials in NASH may be impeded by the lack of a systematic approach to identify and evaluate how lifestyle changes and/or modifications influence clinical trial outcomes and associated endpoints. Furthermore, there are additional uncertainties regarding the methods that can be utilised to better characterise and quantify lifestyle variables - which can influence disease activity and alter trial endpoints - to allow for comparisons of trial outcomes across different phases of research and/or within drug-classes. This summary by the Liver Forum's Standard of Care Working Group reviews currently available clinical data, identifies the barriers and challenges associated with the standard of care in NAFLD/NASH clinical trials, defines available assessments of lifestyle changes, and proposes approaches to better understand and define the influence of diet and exercise on NASH treatment in the context of different pharmacologic interventions. The ultimate objective is to propose tangible solutions which enable investigators, sponsors, and regulatory authorities to meaningfully interpret clinical trial outcomes and the impact of lifestyle modification on such outcomes as they pertain to phase I-IV clinical trials. (C) 2020 Published by Elsevier B.V. on behalf of European Association for the Study of the Liver.
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- 2020
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3. Inclusion and diversity in clinical trials: Actionable steps to drive lasting change
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Michelle D. Kelsey, Bray Patrick-Lake, Raolat Abdulai, Uli C. Broedl, Adam Brown, Elizabeth Cohn, Lesley H. Curtis, Chris Komelasky, Michael Mbagwu, George A. Mensah, Robert J. Mentz, Amesika Nyaku, Stephanie O. Omokaro, Judy Sewards, Kendal Whitlock, Xinzhi Zhang, and Gerald S. Bloomfield
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United States Food and Drug Administration ,Humans ,Pharmacology (medical) ,General Medicine ,Article ,Research Personnel ,United States - Abstract
BACKGROUND: Improving diversity in clinical trials is essential in order to produce generalizable results. Although the importance of representation has become increasingly recognized, identifying strategies to approach this work remains elusive. This article reviews the proceedings of a multi-stakeholder conference about the current state of diversity in clinical trials and outlines actionable steps for improvement. METHODS: Conference attendees included representatives from the United States Food and Drug Administration (FDA), National Institutes of Health (NIH), practicing clinical investigators, pharmaceutical and device companies, community-based organizations, data analytics companies, and patient advocacy groups. At this virtual event, attendees were asked to consider key questions around best practices for engagement of underrepresented populations. RESULTS: Community engagement is an integral part of recruitment and retention of underrepresented groups. Decentralization of sites and use of digital tools can enhance the accessibility of clinical research. Finally, improving representation among investigators and clinical research staff may translate to diverse clinical trial participants. CONCLUSION: Improving diversity in clinical trials is an ethical and scientific imperative, which requires a multifaceted approach.
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- 2022
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4. The regulatory state of nonalcoholic steatohepatitis and metabolism
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Julie K. Golden and Stephanie O. Omokaro
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Nonalcoholic steatohepatitis ,lcsh:RC648-665 ,Editorial ,business.industry ,Endocrinology, Diabetes and Metabolism ,Regulatory state ,Medicine ,Metabolism ,Bioinformatics ,business ,lcsh:Diseases of the endocrine glands. Clinical endocrinology - Published
- 2020
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5. Best practices for detection, assessment and management of suspected immune-mediated liver injury caused by immune checkpoint inhibitors during drug development
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Naga Chalasani, Stephanie O. Omokaro, Syed Asif Haque, Herbert L. Bonkovsky, Nonko D. Pehlivanov, Adrian M. Di Bisceglie, Paul B. Watkins, Karen Price, James W. Freston, Mark I. Avigan, Hewei Li, Melanie J. Harrison, Arie Regev, John M. Vierling, Gerd A. Kullak-Ublick, Ethan Miller, James H. Lewis, Niti N. Patel, Jack Uetrecht, Alexandre Kiazand, Meenal Patwardhan, Robert J. Fontana, University of Zurich, Regev, Arie, and Chalasani, Naga P
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0301 basic medicine ,Drug ,medicine.medical_specialty ,media_common.quotation_subject ,Immunology ,Psychological intervention ,610 Medicine & health ,03 medical and health sciences ,0302 clinical medicine ,Drug Development ,Liver Function Tests ,Neoplasms ,medicine ,Immunology and Allergy ,Animals ,Humans ,Intensive care medicine ,Adverse effect ,Immune Checkpoint Inhibitors ,media_common ,030203 arthritis & rheumatology ,2403 Immunology ,Mechanism (biology) ,business.industry ,Disease Management ,Discontinuation ,Clinical trial ,030104 developmental biology ,Drug development ,10199 Clinic for Clinical Pharmacology and Toxicology ,Inclusion and exclusion criteria ,2723 Immunology and Allergy ,Disease Susceptibility ,Chemical and Drug Induced Liver Injury ,business - Abstract
Immune checkpoint inhibitors (ICIs) have shown significant efficacy in patients with various malignancies, however, they are associated with a wide range of immune-related toxicities affecting many organs, including the liver. Immune-mediated liver injury caused by checkpoint inhibitors (ILICI) is a distinctive form of drug induced liver injury (DILI), that differs from most DILI types in presumed underlying mechanism, incidence, and response to therapeutic interventions. Despite increased awareness of ILICI and other immune-related adverse effects of ICIs reflected by recent guidelines for their management in post marketing clinical practice, there is lack of uniform best practices to address ILICI risk during drug development. As efforts to develop safer and more effective ICIs for additional indications grow, and as combination therapies including ICIs are increasingly investigated, there is a growing need for consistent practices for ILICI in drug development. This publication summarizes current best practices to optimize the monitoring, diagnosis, assessment, and management of suspected ILICI in clinical trials using ICI as a single agent and in combination with other ICIs or other oncological agents. It is one of several publications developed by the IQ DILI Initiative in collaboration with DILI experts from academia and regulatory agencies. Recommended best practices are outlined pertaining to hepatic inclusion and exclusion criteria, monitoring of liver tests, ILICI detection, approach to a suspected ILICI signal, causality assessment, hepatic discontinuation rules and additional medical treatment.
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- 2020
6. Attribution of Nonalcoholic Steatohepatitis as an Etiology of Cirrhosis for Clinical Trials Eligibility: Recommendations From the Multi-stakeholder Liver Forum
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Mazen Noureddin, Jean L. Chan, Katherine Barradas, Lara Dimick-Santos, Elmer Schabel, Stephanie O. Omokaro, Frank A. Anania, Robert P. Myers, Veronica Miller, Arun J. Sanyal, Naga Chalasani, Jasmohan Bajaj, Annalisa Berzigotti, Pascal Birman, Jaime Bosch, Ashley Brower, Dania Calboli, William Charlton, Klara Dickinson, Claudia Filozof, Mikael F. Forsgren, Michael Fuchs, Guadalupe Garcia-Tsao, Juan Gonzalez-Abraldes, Hans-Juergen Gruss, Morten Hansen, Suneil Hosman, Joanne Imperial, David Jones, Gadi Lalazar, Olof Dahlqvist Leinhard, Erica Lyons, Brian McColgan, Ruby Mehta, Peter Mesenbrink, Rob Myers, Veronica Pei, Vlad Ratziu, Arie Regev, Robert Riccio, Arun Sanyal, Suna Seo, Alastair Smith, Peter Szitanyi, and Peter Traber
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Nonalcoholic steatohepatitis ,Liver Cirrhosis ,medicine.medical_specialty ,Cirrhosis ,Consensus ,MEDLINE ,Non-alcoholic Fatty Liver Disease ,Stakeholder Participation ,medicine ,Humans ,Multi stakeholder ,Healthy Lifestyle ,Intensive care medicine ,Clinical Trials as Topic ,Hepatology ,business.industry ,Patient Selection ,Gastroenterology ,Drugs, Investigational ,medicine.disease ,Clinical trial ,Liver ,Practice Guidelines as Topic ,Etiology ,Attribution ,business - Published
- 2019
7. Factors to Consider in Development of Drugs for Pediatric Nonalcoholic Fatty Liver Disease
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Miriam B. Vos, Lara Dimick-Santos, Ruby Mehta, Stephanie O. Omokaro, Johannes Taminiau, Elmer Schabel, David E. Kleiner, Peter Szitanyi, Piotr Socha, Jeffrey B. Schwimmer, Stephanie Noviello, Debra G. Silberg, Richard Torstenson, Veronica Miller, Joel E. Lavine, Nathalie Adda, William Baldyga, Rajarshi Banerjee, Cynthia Behling, Sherif Boulos, Gary Burgess, Dania Calboli, Edgar Charles, Rose Christian, Claude Cohen-Bacrie, Doina Cosma-Roman, Claus-Peter Danzer, Ingrid Delaet, Mark Delegge, Nicholas DiProspero, Kathleen Donohue, Laurent Fischer, Emer Fitzpatrick, Michael Fried, David Hagerty, Paula Hale, Keri Hildick, Dean Hum, Khurram Jamil, Lijuan Jiang, Saul Karpen, Matt Kelly, Rohit Kohli, Kattayoun Kordy, Nancy Krieger, Joel Lavine, Lois Lee, Eric Lefebvre, Patricia Lopez, Erica Lyons, Laura Malahias, Sophie Megnien, Peter Mesenbrink, Pansy Minnick, Christine Murray, Tien Nghiem, Nikki Nicholson, Wenjie Pang, Lisa Percival, Dan Peres, Margaret Powell, Dragos Roman, Mark Root, Claire Sampson, Arun Sanyal, Kathleen Schwarz, Star Seyedkazemi, David Shapiro, Reshma Shringarpure, Debra Silberg, Edward Smith, Robert Squires, William Treem, Pamela Vig, Miriam Vos, Mason Yamashita, Michael Zemel, and Liver Forum Pediat Working Grp
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medicine.medical_specialty ,MEDLINE ,Gastroenterology ,Severity of Illness Index ,Article ,Drug Development ,Non-alcoholic Fatty Liver Disease ,Internal medicine ,Nonalcoholic fatty liver disease ,Severity of illness ,medicine ,Prevalence ,Humans ,Child ,Clinical Trials as Topic ,Hepatology ,business.industry ,Patient Selection ,Age Factors ,medicine.disease ,Drug development ,Liver ,Human medicine ,business ,Liver pathology - Published
- 2019
8. Lymphocytes with aberrant expression of Fas or Fas ligand attenuate immune bone marrow failure in a mouse model
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Neal S. Young, Stephanie O. Omokaro, Jichun Chen, Felicia M. Ellison, Michael Eckhaus, and Marie J. Desierto
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Mice, Inbred MRL lpr ,Fas Ligand Protein ,Lymphocyte ,T cell ,Immunology ,Apoptosis ,Biology ,Fas ligand ,Article ,Mice ,Mice, Congenic ,medicine ,Immunology and Allergy ,Cytotoxic T cell ,Animals ,fas Receptor ,Bone Marrow Diseases ,Bone marrow failure ,Fas receptor ,medicine.disease ,Lymphocyte Subsets ,Lymphoproliferative Disorders ,Mice, Mutant Strains ,Clone Cells ,Mice, Inbred C57BL ,Disease Models, Animal ,medicine.anatomical_structure ,Gene Expression Regulation ,Cancer research ,Bone marrow - Abstract
Bone marrow (BM) and lymphocyte samples from aplastic anemia patients show up-regulated Fas and Fas-ligand (FasL) expression, respectively, supporting a relationship between immune-mediated BM destruction and the Fas apoptotic pathway. Mice with spontaneous lymphoproliferation (lpr) and generalized lymphoproliferative disease (gld) mutations exhibit abnormal expression of Fas and FasL, serving as potential models to elucidate underlying mechanisms of BM failure. We examined cellular and functional characteristics of lpr and gld mutants on the C57BL/6 (B6) background. Lymph node (LN) cells from lpr and gld mice produced less apoptosis when coincubated with C.B10-H2b/LilMcd (C.B10) BM cells in vitro. This functional difference was confirmed by infusing lpr, gld, and B6 LN cells into sublethally irradiated CB10 mice. All donor LN cells showed significant T cell expansion and activation, but only B6 LN cells caused severe BM destruction. Mice infused with gld LN cells developed mild to moderate BM failure despite receiving FasL-deficient effectors, thus suggesting the existence of alternative pathways or incomplete penetrance of the mutation. Paradoxically, mice that received Fas-deficient lpr LN cells also had reduced BM failure, likely due to down-regulation of proapoptotic genes, an effect that can be overcome by higher doses of lpr LN cells. Our model demonstrates that abnormal Fas or FasL expression interferes with the development of pancytopenia and marrow hypoplasia, validating a major role for the Fas/FasL cytotoxic pathway in immune-mediated BM failure, although disruption of this pathway does not completely abolish marrow destruction.
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- 2009
9. Epstein-Barr virus-associated central nervous system lymphoproliferative disease in a patient with acquired immunodeficiency syndrome responsive to highly active antiretroviral therapy
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Erica M. Sibinga, Zarir E. Karanjawala, Stephanie O. Omokaro, Mary Joyner, Aaron M. Milstone, Alan D. Friedman, Dennis Z. Kuo, Neal A. Halsey, and Michael J. Borowitz
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Microbiology (medical) ,Adult ,Central Nervous System ,Male ,Herpesvirus 4, Human ,medicine.medical_treatment ,Lymphoproliferative disorders ,medicine.disease_cause ,Herpesviridae ,Virus ,Acquired immunodeficiency syndrome (AIDS) ,Immunopathology ,Antiretroviral Therapy, Highly Active ,Medicine ,Humans ,Acquired Immunodeficiency Syndrome ,business.industry ,medicine.disease ,Epstein–Barr virus ,Lymphoproliferative Disorders ,Radiation therapy ,Infectious Diseases ,Treatment Outcome ,Immunology ,Viral disease ,business - Abstract
A 20-year-old man with acquired immunodeficiency syndrome (AIDS) and central nervous system (CNS) lymphoproliferative disease experienced improvement with highly active antiretroviral therapy (HAART) without radiation therapy. Our experience highlights the importance of biopsy in evaluating multifocal radiographic CNS lesions and the central role of HAART in treating AIDS-related CNS disease.
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- 2008
10. Enrichment of hematopoietic stem cells with SLAM and LSK markers for the detection of hematopoietic stem cell function in normal and Trp53 null mice
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Michael A. Eckhaus, Marie J. Desierto, Keyvan Keyvanfar, Neal S. Young, Stephanie O. Omokaro, Felicia M. Ellison, and Jichun Chen
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Cancer Research ,animal diseases ,Proto-Oncogene Proteins pp60(c-src) ,Bone Marrow Cells ,Mice, Inbred Strains ,Receptors, Cell Surface ,Lymphocyte Activation ,Article ,Mice ,Antigen ,Signaling Lymphocytic Activation Molecule Family Member 1 ,In vivo ,Antigens, CD ,Genetics ,medicine ,Animals ,Molecular Biology ,Mice, Knockout ,biology ,CD117 ,Hematopoietic stem cell ,Cell Biology ,Hematology ,CD48 ,Hematopoietic Stem Cells ,Molecular biology ,Haematopoiesis ,medicine.anatomical_structure ,Immunology ,biology.protein ,Bone marrow ,Stem cell ,Tumor Suppressor Protein p53 ,Reactive Oxygen Species ,Biomarkers - Abstract
Objective To test function of hematopoietic stem cells (HSCs) in vivo in C57BL/6 (B6) and Trp53-deficient (Trp53 null) mice by using two HSC enrichment schemes. Materials and Methods Bone marrow (BM) Lin − CD41 − CD48 − CD150 + (signaling lymphocyte activation molecules [SLAM]), Lin − CD41 − CD48 − CD150 − (SLAM − ) and Lin − Sca1 + CD117 + (LSK) cells were defined by fluorescence-activated cell staining (FACS). Cellular reactive oxygen species (ROS) level was also analyzed by FACS. Sorted SLAM, SLAM − , and LSK cells were tested in vivo in the competitive repopulation (CR) and serial transplantation assays. Results SLAM cell fraction was 0.0078% ± 0.0010% and 0.0135% ± 0.0010% of total BM cells in B6 and Trp53 null mice, and was highly correlated ( R 2 = 0.7116) with LSK cells. CD150 + BM cells also contained more ROS low cells than did CD150 − cells. B6 SLAM cells repopulated recipients much better than B6 SLAM − cells, showing high HSC enrichment. B6 SLAM cells also engrafted recipients better than Trp53 null SLAM cells in the CR and the follow-up serial transplantation assays. Similarly, LSK cells from B6 donors also had higher repopulating ability than those from Trp53 null donors. However, whole BM cells from the same B6 and Trp53 null donors showed the opposite functional trend in recipient engraftment. Conclusion Both SLAM and LSK marker sets can enrich HSCs from B6 and Trp53 mice. Deficiency of Trp53 upregulates HSC self-renewal but causes no gain of HSC function.
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- 2007
11. Fas- and Fas Ligand Rather Than Perforin-Mediated Apoptosis Has a Dominant Role in Target Cell Death in Murine Models of Immune- Mediated Bone Marrow Failure
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Annahita Sarcon, Neal S. Young, Jichun Chen, and Stephanie O. Omokaro
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biology ,Chemistry ,T cell ,Immunology ,Cell Biology ,Hematology ,Biochemistry ,Fas ligand ,medicine.anatomical_structure ,Perforin ,Granzyme ,Apoptosis ,medicine ,Fas signaling pathway ,Cancer research ,biology.protein ,Cytotoxic T cell ,Bone marrow - Abstract
Fas-Fas ligand and perforin-granzyme are two important cell death pathways associated with cytotoxic T cell induced target cell apoptosis. In patients with immune-mediated aplastic anemia, the development of bone marrow (BM) failure is associated with up-regulation in Fas ligand expression on effector cytotoxic T cells and elevated Fas expression on target BM cells. In some aplastic anemia patients, peripheral blood T lymphocytes also carry polymorphisms in the perforin gene which have been associated with familial hemophagocytosis. These findings suggested that Fas ligand/Fas might be the key signaling molecules mediating cell destruction while perforin might also play a role in the development of BM failure in patients with aplastic anemia. We have modeled immune-mediated BM failure in the mouse by infusing allogeneic lymph node (LN) cells from C57BL/6 (B6) donors into sublethally-irradiated CByB6F1 and C.B10 recipients that are mismatched at either major histocompatibility (MHC) or minor histocompatibility (minor-H) loci. Expansion and activation of allogeneic T cells results in increased production of the inflammatory cytokines gamma interferon and tissue necrosis factor alpha in recipient BM, massive BM cell destruction, severe marrow hypoplasia, and fatal pancytopenia. In the current study, we directly tested the roles of Fas, Fas ligand and perforin in the development of BM failure by using murine models with spontaneous mutations at the lymphoproliferation (lpr) and generalized lymphoproliferative disease (gld) loci, or with germline deletion of the gene perforin (prf−/−). Fas and Fas ligand-deficient lpr and gld mutant mice had no evidence of hematopoietic deficiency despite their autoimmune environment and marked lymphoproliferation. LN cells from lpr and gld mice caused significantly less apoptosis to minor-H mismatched C.B10 BM cells when co-cultured in a cytotoxicity assay in vitro, in comparison to LN cells from wild-type B6 mice. Infusion of lpr, gld, and B6 donor LN cells into sub-lethally irradiated CB10 recipients all caused massive T cell expansion in recipient BM with high level expression of CD11a, indicative of T cell activation, but only B6 LN cells caused severe BM destruction. In contrast, recipients of lpr and gld LN cells had only mild to moderate pancytopenia and marrow hypocellularity. We inferred from these results that disruption of the Fas ligand/Fas signaling pathway effectively abrogated immune mediated marrow destruction. To test the role of perforin in BM failure, we first analyzed prf−/−- mice and found no obvious change in cellular composition in lymphohematopoietic tissues in comparison to wild-type B6 controls. LN cells from prf−/− mice showed reduced ability to induce C.B10 BM cell apoptosis in an in vitro cytotoxicity assay when compared to wild-type B6 LN cells. Infusion of 5–10 million prf−/− LN cells into CByB6F1 and C.B10 recipients produced obvious BM failure in both recipient types with pancytopenia and marrow hypoplasia about 80–90% as severe as in control recipients of 5 million B6 LN cells. In both CByB6F1 and C.B10 recipients, infused prf−/− LN cells resulted in less T cell expansion, a similar level of T cell activation, higher proportions of T cells containing gamma-interferon and tissue necrosis factor-alpha, and a higher proportion of T cells expressing the Fas ligand CD178, in comparison to the infused B6 LN cells. We conclude that Fas-Fas ligand-mediated transmembrane signaling provides the major cell death pathway, while perforin-granzyme-mediated exocytosis plays a minor role, in BM cell destruction in animal models of immune-mediated BM failure.
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- 2008
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12. Utlilizing Mutant Mice To Dissect Immune Bone Marrow Failure: Markedly Reduced Cytotoxicity of Lymphocytes from Fas- and Fas Ligand-Deficient Mice in Lymph Node Cell-Mediated Aplastic Anemia
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Stephanie O. Omokaro, Neal S. Young, Felicia M. Ellison, Jichun Chen, and Keyvan Keyvanfar
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Lymphocyte ,T cell ,Immunology ,Bone marrow failure ,Cell Biology ,Hematology ,Biology ,medicine.disease ,Biochemistry ,Haematopoiesis ,medicine.anatomical_structure ,medicine ,Cytotoxic T cell ,Bone marrow ,Aplastic anemia ,CD8 - Abstract
Key cellular events in the development of aplastic anemia are activation and expansion of T cells that are destructive of hematopoietic tissue. Human immune-mediated bone marrow failure has been modeled in mice by infusion of lymph node (LN) cells into major- or minor-histocompatibility antigen mismatched recipients; oligoclonal T cell expansion causes indiscriminant hematopoietic cell destruction, marked marrow hypoplasia, and fatal pancytopenia. We have utilized this simple model in order to dissect the molecular events responsible for T cell mediated, selective organ destruction. In mice with spontaneous mutations: lymphoproliferation (lpr) and generalized lymphoproliferative disease (gld), animals have an abnormal increase in lymphocytes and develop clinical manifestations similar to those seen in patients with systemic lupus erythematosus (SLE). In contrast to human SLE, the lpr and gld bone marrow appear unaffected by this typically self-destructive process. We examined C57BL/6 (B6) mice that carry the lpr and gld mutations along with normal B6 mice to define cellular and functional differences as they relate to BM damage. In our initial analyses of peripheral blood (PB), we found a reduced CD4 T cell proportion in lpr and gld mice (5.5±1.5%, 4.3±0.6%, 9.9±0.9%) and a reduced CD8 T cell proportion in gld mice when compared to B6 controls (13.4±1.9%, 7.9±0.9%, 12.7±1.8%). In the BM, both CD4 (1.5±0.3%, 2.3±0.3%, 1.0±0.1%) and CD8 (2.9±0.3%, 3.1±0.7%, 2.6±0.2%) T cell proportions were slightly increased in lpr and gld mice, while total number of BM cells was not significantly different among the three genotypes (438±48, 324±18, 350±27, millions). These findings indicated no PB lymphocyte accumulation and no BM destruction in lpr or gld mice. We then tested the hypothesis that lpr and gld BM cells were more resistant to immune attack by infusing 5 x 106 lymph node (LN) cells from minor-histocompatibility antigen-mismatched C.B10 mice into sublethally-irradiated (5 Gys) lpr, gld, and B6 recipients. At two weeks, all recipients infused with CB10 LN cells had reduced blood neutrophils, and gld and B6 recipients also had reduced RBCs, as compared to mice that did not receive LN cell infusions. This result suggests that lpr and gld hematopoietic cells, like those from B6 mice, are susceptible to immune-mediated destruction. We then examined lymphocyte function by co-incubating lpr, gld and B6 LN cells (effectors) with C.B10 BM cells (targets) in a cytotoxilux assay in vitro. B6 effectors produced 51–78% more apoptotic targets than did gld and lpr effectors. This difference was confirmed by the infusion of lpr, gld (15 x 106 cells/recipient) and B6 (5 x 106 cells/recipient) LN cells into sub-lethally irradiated CB10 mice in vivo. At three weeks, enumeration of blood neutrophils (0.69±0.60, 1.27±0.83, 0.08±0.03), RBCs (3.58±0.42, 4.80±1.20, 4.76±0.36), platelets (274± 94, 400±156, 298±91) and total BM cells (87± 23, 195±78, 82±6, millions) demonstrated that, despite massive lymphoproliferation, lymphocytes from lpr and gld mice were less effective in mediating BM cell destruction. Our results provide evidence supporting the role of Fas and Fas-ligand mediated programmed cell death in immune-mediated BM destruction. The ready availability of genetically modified mice with well characterized functional defects should allow a full description of the molecular pathways in immune-mediated marrow failure in this model.
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- 2007
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13. Enrichment of Hematopoietic Stem Cells from Normal and Trp53 Null Mice Using SLAM Receptor CD150 as a Positive Selection Marker
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Jichun Chen, Stephanie O. Omokaro, Keyvan Keyvanfar, and Neal S. Young
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education.field_of_study ,biology ,Chemistry ,Immunology ,Population ,Spleen ,Cell Biology ,Hematology ,CD48 ,Biochemistry ,Molecular biology ,Haematopoiesis ,medicine.anatomical_structure ,medicine ,biology.protein ,Bone marrow ,Antibody ,Stem cell ,education ,Receptor - Abstract
CD150 is a member of the signaling lymphocyte activation molecule (SLAM) family of receptors which can be used as a positive selection marker for hematopoietic stem cells (HSCs) from mouse bone marrow (BM) and fetal liver (Kiel et al., Cell 2005; Yilmaz et al., Blood 2006; Kim et al., Blood 2006). In the current study, we combined CD150 with a set of lineage-specific markers to enrich HSCs, comparing normal C57BL/6 (B6) mice with B6-Trp53-deficient (Trp53 null) mice which were previously shown to have elevated HSC activity. Using an anti-mouse CD150 antibody (Clone TC 15-12F 12.2, BioLegend), we defined a population of Lin−CD41−CD48−CD150+(SLAM) cells that is 0.0078 ± 0.0010% and 0.0135 ± 0.0010% of total BM cells from B6 and Trp53 null mice. The size of the SLAM cell fraction was strongly correlated (R2= 0.7116, P
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- 2007
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