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）的特征是异常T细胞活化和死亡，这一过程关键依赖于线粒体中活性氧中间体（ROI）和ATP的受控产生。线粒体跨膜电位已最终成为ATP合成和细胞死亡的关键检查点。在正常T细胞中，我们首先确定了线粒体跨膜电位的升高，即，线粒体超极化（MHP），以及其次，ATP耗竭，这是T细胞活化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，这减少了活化诱导的细胞凋亡，反而使T细胞易于坏死，从而刺激SLE中的炎症。因此，确定持续性MHP的分子基础和后果对于理解狼疮T细胞中改变的活化和死亡信号传导的机制至关重要。 我们发现持续MHP与T淋巴细胞中线粒体质量增加和线粒体和细胞质Ca 2+含量增加以及单核细胞中一氧化氮（NO）产生增强有关。在正常T细胞中NO诱导的线粒体生物合成加速了CD 3/CD 28共刺激后的快速期并减少了Ca 2+内流的平台，从而模拟了狼疮T细胞的Ca 2+信号传导谱。由于线粒体是主要的Ca 2+存储，NO依赖的线粒体生物合成可能会改变Ca 2+处理。在狼疮T细胞中，我们确定了控制关键代谢途径的基因表达的变化：诱导谷胱甘肽耗尽和MHP的转醛醇酶（TAL）的过度表达，调节NO区室化生产的eNOS相互作用蛋白（NOSIP）的低表达，以及雷帕霉素受体FKBP 12的过度表达。我们观察到雷帕霉素治疗患者的疾病活动性改善，CD 3/CD 28诱导的Ca 2+流动正常化，MHP持续存在，表明Ca 2+流动改变是线粒体功能障碍的下游或独立。 拟议的研究将测试的假设，通过S-亚硝基化产生的谷胱甘肽消耗在NO的存在下，导致持久的MHP，这反过来又激活哺乳动物的雷帕霉素（mTOR）通路的目标的电子传递链的抑制。首先，我们将测量分离的线粒体中电子传递链的功能能力，并确定GSH耗竭和TAL活化在狼疮T细胞的MHP和ATP耗竭中的作用。第二，我们将确定内在和外在的NO产生的作用，eNOS的区室化表达，并响应NO。第三，我们将研究作为传感器和下游效应器的MHP和控制器的增加Ca 2+通量的mTOR的作用。第四，我们将系统地绘制MHP上游和下游的代谢检查点，并验证候选基因的参与，这些基因可以被靶向以使SLE中的T细胞活化正常化。