Endocytic Control of Autophagosome Formation in Lupus T cells

狼疮 T 细胞中自噬体形成的内吞控制

• 批准号: 9019238
• 负责人: Andras Perl
• 金额: $ 40.38万
• 依托单位: UPSTATE MEDICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-15 至 2021-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9019238
• 关键词: Address; Adverse effects; Affect; Age; Amino Acids; Appearance; Autoimmune Diseases; Autoimmunity; Autophagocytosis; Autophagosome; Back; Biogenesis; CD4 Positive T Lymphocytes; Cell Differentiation process; Cell Survival; Cells; Clinical; Complex; Data; Degradation Pathway; Dependence; Development; Disease; Endosomes; Etiology; Exhibits; FRAP1 gene; Family; Feedback; Female of child bearing age; Flare; Functional disorder; Generations; Genes; Genetic Polymorphism; Goals; Guanosine Triphosphate Phosphohydrolases; Hydroxychloroquine; Immune response; Immune system; In Vitro; Inbred MRL lpr Mice; Inflammatory; Knock-in Mouse; Knowledge; Light; Link; Longitudinal Studies; Lupus; Lysosomes; Mediating; Medical; Microtubule-Associated Proteins; Modeling; Monomeric GTP-Binding Proteins; Mus; Nephritis; Onset of illness; Organelles; Pathogenesis; Pathway interactions; Patients; Play; Population; Prevention; Production; Public Health; Recycling; Regulatory T-Lymphocyte; Research; Role; Secondary to; Sirolimus; Site; Splenocyte; Surface; Systemic Lupus Erythematosus; T-Cell Activation; T-Cell Development; T-Lymphocyte; TFRC gene; Testing; Therapeutic; Work; adaptive immunity; base; chronic autoimmune disease; clinical efficacy; cohort; effective therapy; feeding; gene therapy; in vivo; inhibitor/antagonist; innovation; lupus prone mice; member; mortality; novel therapeutics; overexpression; protein degradation; public health relevance; rab GTP-Binding Proteins; research study; thymocyte; trafficking

 DESCRIPTION (provided by applicant): Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown etiology. The pathogenesis is at least partly attributed to T-cell dysfunction. Therefore, the proposed studies will focus on a critical gap in knowledge - how autophagy pathways that regulate normal T-cell development cause pro-inflammatory population skewing and dysfunction in SLE. The central hypothesis of this project has been based on recent evidence for the contribution of endosomes to the formation of autophagosomes and the role of Rab4A in increased autophagy in lupus T cells. Rab4A is a small GTPase that regulates endosome recycling. It is markedly overexpressed in SLE patients and, even prior to disease onset, in lupus-prone mice. Although autophagy genes, in particular ATG5, have been genetically linked to SLE, their role in pathogenesis is undefined. Notably, ATG5 is transported by CD71+ endosomes which are recycled by Rab4A. Newly developed mice carrying constitutively active Rab4AQ72L show increased expression of CD71 and depletion of ATG5. Splenocytes and thymocytes of these mice show activation of mTORC1 and depletion of FoxP3. While mTORC1 is generally regarded as an inhibitor of autophagy, it is activated on the surface of lysosomes. Thus, based on compelling preliminary data, the Specific Aims will test the working hypothesis that Rab4A overexpression is responsible for accelerated autophagy and, through promoting the traffic of mTORC1 to lysosomes, for abnormal T-cell development in SLE. Given that the GTPase inhibitor 3-PEHPC inactivates Rab4A in vitro and blocks lupus pathogenesis in vivo, the proposed experiments will determine whether 1) Rab4A promotes CD71/ATG5-dependent autophagosome formation in SLE patients; 2) mTORC1 activation and FoxP3 depletion occur through endocytic traffic to lysosomes; and 3) inactivation of Rab4A blocks pathogenesis in lupus-prone mice. Under Aim 1, Rab4A overexpression will be assessed in longitudinal studies of SLE patients as the cause of enhanced autophagosome biogenesis via the retention of CD71. Under Aim 2, Rab4A-initiated traffic of mTOR from inhibitory Rab5+ endosomes to Rheb+ lysosomes will be evaluated as the mechanism underlying mTORC1 activation and the resultant Treg→Th17 trans-differentiation in SLE patients. Under Aim 3, the role of Rab4A-driven autophagy in lupus will be modeled by the impact of constitutively active Rab4AQ72L on development of autoimmunity and the dependence of pathogenesis on Rab4A, ATG5 and ATG7 and downstream activation of mTORC1 and inhibition of mTORC2. The proposed research is significant because it will advance our basic understanding of autophagosome biogenesis and its impact on T-cell development and plasticity with broad translational relevance for the pathogenesis and treatment of lupus. The approach is innovative as it will employ genetically defined checkpoints of endosomal traffic to influence lupus pathogenesis. The results will bring new perspectives to our understanding of endosome traffic, how it controls autophagosome formation and its role in disease pathogenesis, and will identify new mechanistic targets for treatment of SLE.

 描述（由适用提供）：全身性红斑狼疮（SLE）是一种不明病因的自身免疫性疾病。发病机理至少部分归因于T细胞功能障碍。因此，拟议的研究将集中于知识的关键差距 - 调节正常T细胞发育的自噬途径如何导致SLE的促炎种群偏斜和功能障碍。该项目的中心假设是基于最新证据表明内体对自噬体形成的贡献以及Rab4a在狼疮T细胞中自噬增加的作用。 Rab4a是一个小的GTPase，可调节内体回收。它在SLE患者中，甚至在疾病发作之前，都明显过表达，在容易发生的小鼠中。尽管自噬基因（尤其是ATG5）与SLE有遗传有关，但它们在发病机理中的作用是不确定的。值得注意的是，ATG5由CD71+内体运输，后者由Rab4a回收。新开发的携带活性RAB4AQ72L的小鼠显示CD71的表达增加和ATG5的部署。这些小鼠的脾细胞和胸腺细胞显示MTORC1的激活和FOXP3的部署。虽然MTORC1通常被认为是自噬的抑制剂，但在溶酶体表面被激活。这是基于引人注目的初步数据，具体目的将检验rab4a过表达的工作假设，即Rab4a过表达负责加速自噬，并通过促进MTORC1到溶酶体的流量，用于SLE的异常T细胞发育。鉴于GTPa​​se抑制剂3-PEHPC在体外会使Rab4a失活并阻断体内狼疮的发病机理，因此提出的实验将确定1）RAB4A是否促进了SLE患者的CD71/ATG5依赖性自噬体形成； 2）MTORC1激活和FOXP3部署通过溶酶体的内吞流量进行； 3）Rab4a的失活阻断了狼疮易发的小鼠的发病机理。在AIM 1下，将在SLE患者的纵向研究中评估RAB4A的过表达，这是通过保留CD71来增强自噬体生物发生的原因。在AIM 2下，RAB4A引起的MTOR流量从抑制性RAB5+内体到RHEB+溶酶体将被评估为MTORC1激活的基础机制和SLE患者的TREG→TH17 TREG→TH17 TREG差异。在AIM 3下，RAB4A驱动的自噬在狼疮中的作用将由组成型活性的RAB4AQ72L对自身免疫发展的发展以及发病机理对RAB4A，ATG5和ATG7和ATG7的依赖性以及MTORC1的下游激活以及MTORC2的下游激活以及MTORC2的下游激活。拟议的研究之所以重要，是因为它将提高我们对自噬体生物发生的基本理解及其对T细胞发育和可塑性的影响，并且对狼疮的发病机理和治疗具有广泛的转化相关性。该方法具有创新性，因为它将采用内体流量的遗传定义检查点来影响狼疮的发病机理。结果将为我们对内体流量的理解带来新的看法，它如何控制自噬体形成及其在疾病发病机理中的作用，并将确定用于治疗SLE的新机械目标。