gp96, TLR and immunologic tolerance

描述（由申请人提供）：热休克蛋白gp 96是内质网（ER）中介导ER未折叠蛋白反应（UPR）的关键下游分子伴侣。转基因小鼠中gp 96的细胞表面表达导致自发性狼疮样自身免疫性疾病，其依赖于肠道细菌和Toll样受体4（TLR 4）。这一发现，以及gp 96是TLR的主伴侣的发现，使该领域向前发展显着：我们现在假设gp 96通过陪伴TLR而不是通过TLR的信号传导来调节免疫系统;根据其表达水平和位置，如果gp 96上调，则可以破坏耐受性，如果表达或功能受损，则可以赋予免疫缺陷。TLR 4在狼疮中先前未被认识到的作用已经通过TLR 4过表达小鼠中的狼疮得到验证。对gp 96转基因小鼠自身免疫机制的研究也揭示了慢性TLR高反应性对肠道植物群产生IL-10的CD 4？体内T细胞（TR 1）和分泌IL-17的CD 4细胞（TH 17）。在这项提案中，我们将严格解决的假设，TLR 4扩增在DNA水平或翻译后水平显着影响的生物学（启动，维护和功能）的TR 1和TH 17，导致外周耐受性的崩溃。我们还将定义TLR在驱动狼疮中的层次结构，特别关注我们模型中核酸敏感TLR的作用。我们的研究对于理解TLR通过调节TR 1和TH 17在免疫和耐受中的作用具有重要意义，因为这些细胞类型的失调越来越多地涉及自身免疫性疾病。我们最近的研究发现，gp 96的表面表达在体内是高度调节的，并且细胞表面gp 96的表达增加与人类狼疮相关，这突出了我们研究的临床意义。 公共卫生相关性：该项目涉及狼疮的机制，这对理解一般免疫生物学，癌症免疫和其他自身免疫性疾病具有影响。我们的目标是证明这一假设，即特定细胞表面应激蛋白的过度表达导致对微生物的反应增强，这反过来又通过对两个关键免疫调节细胞的复杂作用引发自身免疫的发展。

DESCRIPTION (provided by applicant): Heat shock protein gp96 is a key downstream chaperone in the endoplasmic reticulum (ER) that mediates ER unfolded protein responses (UPR). Cell surface expression of gp96 in a transgenic mouse leads to spontaneous lupus-like autoimmune disease which is dependent on commensal bacteria and Toll-like receptor 4 (TLR4). This finding, together with the discovery that gp96 is a master chaperone for TLRs, has moved the field forward significantly: we now hypothesize that gp96 tunes the immune system by chaperoning TLRs but not by signaling through TLRs; depending on its expression level and location, gp96 can break tolerance if upregulated and can confer immunodeficiency if compromised in expression or function. The previously unappreciated roles of TLR4 in lupus have been validated by lupus in TLR4-overexpressing mice. Studies of the mechanism of autoimmunity in gp96 transgenic mice have also uncovered the potential impact of chronic TLR hyperresponsiveness to commensal flora on IL-10-producing CD4? T cells (TR1) and IL-17-secreting CD4 cells (TH17) in vivo. In this proposal, we will critically address the hypothesis that TLR4 amplification at either DNA level or post translational level significantly impact the biology (priming, maintenance and function) of both TR1 and TH17, leading to breakdown of peripheral tolerance. We will also define the hierarchy of TLRs in driving lupus with particular focus on the roles of nucleic acid-sensing TLRs in our model. Our study is of fundamental significance in understanding the roles of TLRs in immunity and tolerance via regulating TR1 and TH17, since the dysregulation of these cell types has been increasingly implicated in autoimmune diseases. Our recent findings that the surface expression of gp96 is highly regulated in vivo and that the increased expression of gp96 on the cell surface correlates with human lupus highlight the clinical relevance of our study. PUBLIC HEALTH RELEVANCE: This project addresses the mechanism of lupus, which has implications in the understanding of general immunobiology, cancer immunity and other autoimmune diseases. We aim to prove the hypothesis that the overexpression of particular cell surface stress proteins leads to heightened responses against microbes, which in turn triggers the development of autoimmunity through complex actions on two critical immune regulatory cells.