Metabolic control of systemic autoimmunity

全身自身免疫的代谢控制

• 批准号: 7558972
• 负责人: Andras Perl
• 金额: $ 44.88万
• 依托单位: UPSTATE MEDICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-02-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7558972
• 关键词: 11p15.5; ATP Synthesis Pathway; Accounting; Activities of Daily Living; African American; Apoptosis; Autoimmunity; Biogenesis; CD8B1 gene; Candidate Disease Gene; Cell Death; Cell membrane; Cells; Cessation of life; Co-Immunoprecipitations; Complex; Defect; Disease; Electron Transport; Endoplasmic Reticulum; Enzymes; Exhibits; Gene Expression; Genes; Genetic; Genetic Polymorphism; Glutathione; Hand; ITPR1 gene; Inflammation; Inositol; Interferons; Lupus; Lymphocyte; Maps; Measures; Mediating; Membrane Potentials; Metabolic; Metabolic Control; Metabolic Pathway; Mitochondria; Molecular; NADP; Necrosis; Nitric Oxide; Nitric Oxide Synthase; Organelles; Outer Mitochondrial Membrane; PTPRC gene; Pathway interactions; Patients; Pentosephosphate Pathway; Phase; Process; Production; Protein Isoforms; Proteins; Proton-Translocating ATPases; Rheumatoid Arthritis; Role; Ryanodine Receptor Calcium Release Channel; Ryanodine Receptors; Signal Transduction; Sirolimus; Stream; Systemic Lupus Erythematosus; T-Cell Activation; T-Cell Depletion; T-Lymphocyte; T-Lymphocyte Subsets; Tacrolimus Binding Protein 1A; Testing; Transaldolase; Transfection; Up-Regulation; adeno-associated viral vector; base; enzyme pathway; human NOS3 protein; inorganic phosphate; member; mitochondrial dysfunction; monocyte; reactive oxygen intermediate; receptor; sensor; stem

DESCRIPTION (provided by applicant): Systemic lupus erythematosus (SLE) is characterized by abnormal T-cell activation and death, processes which are crucially dependent on the controlled production of reactive oxygen intermediates (ROI) and of ATP in mitochondria. The mitochondrial transmembrane potential has conclusively emerged as a critical checkpoint of ATP synthesis and cell death. In normal T cells, we firstly identified the elevation of the mitochondrial transmembrane potential, i.e., mitochondrial hyperpolarization (MHP), and, secondly, also ATP depletion, which are early and reversible steps of T-cell activation and apoptosis. Conversely, in SLE patients, we found that T cells exhibit persistent MHP as well as ATP and glutathione depletion which decrease activation-induced apoptosis and instead predispose T cells for necrosis, thus stimulating inflammation in SLE. Therefore, determining the molecular basis and consequences of persistent MHP is essential for understanding the mechanism of altered activation and death signaling in lupus T cells. We found persistent MHP to be associated with increased mitochondrial mass and increased mitochondrial and cytoplasmic Ca2+ content in T lymphocytes and also with enhanced nitric oxide (NO) production in monocytes. NO-induced mitochondrial biogenesis in normal T cells accelerates the rapid phase and reduces the plateau of Ca2+ influx upon CD3/CD28 costimulation, thus mimicking the Ca2+ signaling profile of lupus T cells. Since mitochondria are major Ca2+ stores, NO-dependent mitochondrial biogenesis may account for altered Ca2+ handling. In lupus T cells, we identified changes in expression of genes that control key metabolic pathways: over-expression of transaldolase (TAL) which induces glutathione depletion and MHP, low expression of eNOS-interacting protein (NOSIP) that regulates compartmentalized production of NO, and over-expression of the rapamycin receptor FKBP12. We observed improvement of disease activity, normalization of CD3/CD28-induced Ca2+ fluxing, and persistence of MHP in rapamycin-treated patients, suggesting that altered Ca2+ fluxing is downstream or independent of mitochondrial dysfunction. The proposed studies will test the hypothesis that inhibition of the electron transport chain via S-nitrosylation stemming from glutathione depletion in the presence of NO causes persistent MHP which, in turn, activates the mammalian target of rapamcyin (mTOR) pathway. First, we will measure functional capacity of the electron transport chain in isolated mitochondria and determine the role of GSH depletion and TAL activation in MHP and ATP depletion of lupus T cells. Second, we will determine the role of intrinsic and extrinsic NO production, compartmentalized expression of eNOS, and responsiveness to NO. Third, we will examine the role of mTOR as a sensor and down-stream effector of MHP and controller of increased Ca2+ fluxing. Fourth, we will systematically map metabolic checkpoints upstream and downstream of MHP and validate the involvement of candidate genes that can be targeted to normalize T-cell activation in SLE.

描述（由申请人提供）：系统性红斑狼疮（SLE）以异常t细胞活化和死亡为特征，这一过程主要依赖于线粒体中活性氧中间体（ROI）和ATP的受控产生。线粒体跨膜电位是ATP合成和细胞死亡的关键检查点。在正常T细胞中，我们首先发现了线粒体跨膜电位的升高，即线粒体超极化（MHP），其次，还有ATP耗竭，这是T细胞激活和凋亡的早期和可逆步骤。相反，在SLE患者中，我们发现T细胞表现出持续的MHP以及ATP和谷胱甘肽耗竭，从而减少激活诱导的细胞凋亡，反而使T细胞易于坏死，从而刺激SLE的炎症。因此，确定持续性MHP的分子基础和后果对于理解狼疮T细胞活化和死亡信号改变的机制至关重要。