Metabolic control of systemic autoimmunity

全身自身免疫的代谢控制

• 批准号: 7758380
• 负责人: Andras Perl
• 金额: $ 31.09万
• 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/7758380
• 关键词: ATP Synthesis Pathway; Accounting; Activities of Daily Living; Address; Apoptosis; Autoimmunity; Biogenesis; Candidate Disease Gene; Cell Death; Cells; Cessation of life; Consultations; Critiques; Data; Defect; Disease; Electron Transport; Exhibits; Figs - dietary; Gene Expression; Genes; Glutathione; Hydroxychloroquine; In Vitro; Inflammation; Inherited; Laboratories; Lupus; Maps; Measures; Membrane Potentials; Metabolic; Metabolic Control; Metabolic Pathway; Mitochondria; Mitochondrial DNA; Mitochondrial Proteins; Molecular; Necrosis; Nitric Oxide; Nuclear; Pathology; Pathway interactions; Patients; Pharmaceutical Preparations; Phase; Phosphorylation; Prednisone; Process; Production; Protein Biosynthesis; Proteins; Publications; Published Comment; RNA; Recording of previous events; Role; SOD2 gene; Signal Transduction; Sirolimus; Stream; Systemic Lupus Erythematosus; T-Cell Activation; T-Lymphocyte; Tacrolimus Binding Protein 1A; Testing; Transaldolase; Transfer RNA; Voltage-Dependent_Anion_Channel-1; Western Blotting; Work; Writing; base; innovation; mitochondrial dysfunction; monocyte; mycophenolate mofetil; rRNA Genes; reactive oxygen intermediate; receptor; sensor; small hairpin RNA; 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 T 细胞异常激活和死亡，该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)，其次确定了 ATP 耗竭，这是 T 细胞激活和凋亡的早期且可逆的步骤。相反，在 SLE 患者中，我们发现 T 细胞表现出持续的 MHP 以及 ATP 和谷胱甘肽消耗，这会减少激活诱导的细胞凋亡，反而使 T 细胞容易坏死，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了解狼疮 T 细胞激活和死亡信号传导改变的机制至关重要。 我们发现持久的 MHP 与 T 淋巴细胞中线粒体质量的增加以及线粒体和细胞质 Ca2+ 含量的增加有关，并且还与单核细胞中一氧化氮 (NO) 产生的增强有关。正常 T 细胞中 NO 诱导的线粒体生物合成可加速 CD3/CD28 共刺激时的快速期并减少 Ca2+ 流入的平台期，从而模仿狼疮 T 细胞的 Ca2+ 信号传导谱。由于线粒体是主要的 Ca2+ 储存库，NO 依赖性线粒体生物发生可能会导致 Ca2+ 处理方式的改变。在狼疮 T 细胞中，我们发现了控制关键代谢途径的基因表达的变化：诱导谷胱甘肽消耗和 MHP 的转醛醇酶 (TAL) 过度表达，调节 NO 区室化产生的 eNOS 相互作用蛋白 (NOSIP) 低表达，以及雷帕霉素受体 FKBP12 的过度表达。我们在雷帕霉素治疗的患者中观察到疾病活动性的改善、CD3/CD28诱导的Ca2+流动的正常化以及MHP的持续存在，这表明Ca2+流动的改变是线粒体功能障碍的下游或独立于线粒体功能障碍。 拟议的研究将检验这样的假设：在 NO 存在的情况下，谷胱甘肽耗尽导致 S-亚硝基化对电子传递链的抑制会导致持久的 MHP，进而激活哺乳动物雷帕霉素靶点 (mTOR) 途径。首先，我们将测量分离线粒体中电子传递链的功能能力，并确定 GSH 消耗和 TAL 激活在狼疮 T 细胞 MHP 和 ATP 消耗中的作用。其次，我们将确定内在和外在 NO 产生的作用、eNOS 的区室化表达以及对 NO 的反应。第三，我们将研究 mTOR 作为 MHP 的传感器和下游效应器以及 Ca2+ 通量增加的控制器的作用。第四，我们将系统地绘制 MHP 上游和下游的代谢检查点图谱，并验证可用于使 SLE 中 T 细胞激活正常化的候选基因的参与。