The Role of Toll-Like Receptor-3 in T1D and Efficacy of a Novel Therapeutic

描述(申请人提供)：1型糖尿病(T1D)是一种自身免疫性疾病，分泌胰岛素的胰岛β细胞被自身免疫系统误认为是外来细胞，并逐渐被破坏。由于身体自身对细胞的破坏，胰岛素产生减少，胰岛素水平变得不足以控制血糖水平，导致T1D。虽然对T1D的病因了解还很少，但人们认为病毒在其发病机制中起着重要的作用。病毒感染细胞可通过多种方式引发疾病，包括直接损伤细胞，释放刺激自身免疫破坏的细胞抗原，或通过各种抗病毒反应对细胞产生毒性。最近的研究表明Toll样受体(TLR)参与了T1D的发病过程。具体地说，TLR是位于免疫细胞上的分子，识别外来抗原并启动保护性免疫反应。最近发现，在新发的T1D患者的胰腺细胞上，TLR3直接异常表达。此外，柯萨奇B组病毒(CBV)可激活TLR3信号通路，加速非肥胖糖尿病(NOD)小鼠T1D的发生，与人类T1D的发生有关。新的TLR信号抑制剂的开发可以阻断这种引起T1D的异常免疫反应，这将为干预和防止T1D发病前的细胞破坏或挽救最初发病的细胞提供潜在的新的治疗范式。苯并咪唑(Phenylmetimazine，C10)是一种化合物，在其他TLR介导的自身免疫性疾病中，如桥本甲状腺炎和系统性红斑狼疮，已被证明可以防止TLR的病理性过度表达和信号转导。因此，C10可能通过抑制TLR3信号转导和细胞因子的产生，预防细胞凋亡(细胞程序性死亡)和/或细胞的免疫破坏，从而具有预防或治疗T1D的潜在疗效。初步研究表明，C10可以预防病毒诱导的NOD小鼠T1D模型的T1D。我们假设(1)T淋巴细胞介导的自身免疫破坏胰岛素分泌细胞，并诱导细胞死亡是病毒激活TLR3信号的结果；(2)C10‘S通过抑制TLR3信号通路发挥有效的抗炎作用，可能预防T1D的发生和/或挽救新发T1D的细胞和保护胰岛素的分泌功能。因此，本研究的具体目的是评估TLR3信号在CBV-4诱导NOD小鼠T1D加速中的作用(S)，并通过研究C10对(I)细胞TLR3信号转导，(Ii)胰岛素(先于T1D的胰腺炎症)，(Iii)细胞数量，以及(Iv)胰腺内特异性免疫细胞群的影响，来评价C10减轻NOD小鼠T1D的CBV-4加速的机制。这些研究将(1)更好地了解TLR3信号在T1D发病机制中的作用，(2)评价一种潜在的治疗/预防T1D的新药的疗效。 公共卫生相关性：Toll样受体(TLRs)最近被认为与环境(病毒)诱发1型糖尿病(T1D)有关。我们研究了T1D病毒诱导通过TLR3介导的可能性，并评价了一种新的TLR信号抑制剂预防/延缓T1D发病的效果。对这些数据的追求可能有助于更好地了解TLR3信号在T1D发病机制中的作用，并评估潜在的治疗/预防T1D的新药的疗效。

DESCRIPTION (provided by applicant): Type 1 Diabetes Mellitus (T1D) is an autoimmune disorder in which pancreatic beta (¿) cells, which produce insulin, are mistaken as foreign by one's own immune system and gradually destroyed. As a result of the body's own destruction of the ¿ cells, insulin production decreases and insulin levels become insufficient to control glucose levels, resulting in T1D. Although the etiology of T1D is only partially understood, it is felt that viruses play an important role in its pathogenesis. Viral infection of ¿ cells is suggested to initiate disease in a variety of ways including direct ¿ cell damage, release of ¿ cell antigens stimulating the autoimmune destruction, or toxicity to the ¿ cells by a variety of antiviral responses. Recent studies have implicated Toll-Like Receptors (TLR) in the pathogenesis of T1D. Specifically, TLR are molecules located on immune cells which recognize foreign antigens and initiate the protective immune response. TLR3 have recently been shown to be abnormally expressed directly on the pancreatic ¿ cells of patients with new onset T1D. In addition, the Coxsackie B virus (CBV), which has been associated with the development of T1D in humans, can activate TLR3 signaling and accelerate the development of T1D in non-obese diabetic (NOD) mice. The development of novel TLR signaling inhibitors which block this aberrant immune response causing T1D would offer a potentially new therapeutic paradigm to intervene and prevent ¿ cell destruction prior to onset of T1D or salvage ¿-cells at initial onset. Phenylmethimazole (C10) is a compound which has been shown to prevent pathologic TLR overexpression and signaling in other TLR-mediated autoimmune diseases such as Hashimoto's Thyroiditis and Systemic Lupus Erythematosis. Thus C10 may have potential efficacy in the prevention or treatment of T1D through inhibition of TLR3 signaling and cytokine production and prevent ¿ cell apoptosis (programmed cell death) and/or immune destruction of ¿ cells. Preliminary studies show that C10 can prevent T1D in a NOD mouse model of virus-induced T1D. We hypothesize (1) that T-lymphocyte-mediated autoimmune destruction of insulin producing ¿ cells, and induction of ¿ cell death is the result of viral-activation of TLR3 signaling in the ¿ cell and (2) that C10's effective anti- inflammatory actions, mediated through the inhibition of TLR3 signaling, may prevent the onset of T1D and/or rescue ¿ cells and preserve insulin secretory function in new-onset T1D. Thus, the specific aim of this proposal is to evaluate the contribution(s) of TLR3 signaling to CBV-4-induced acceleration of T1D in NOD mice and the mechanism by which C10 attenuates CBV-4 acceleration of T1D in the NOD mouse by investigating its effects on (i) ¿ cell TLR3 signaling, (ii) insulitis (inflammation of the pancreas which precedes T1D), (iii) ¿ cell number, and (iv) specific immune cell populations within the pancreas. These studies will (1) provide a better understanding of the involvement of TLR3 signaling in the pathogenesis of T1D, and (2) evaluate the efficacy of a potentially novel new drug for the treatment/prevention of T1D. PUBLIC HEALTH RELEVANCE: Toll-Like Receptors (TLRs) have recently been implicated in environmental (viral) induction of type 1 diabetes (T1D). We investigate the possibility that viral induction of T1D is mediated through TLR3, and evaluate the efficacy of a novel TLR signaling inhibitor to prevent/delay the onset of T1D. Pursuit of these data may provide a better understanding of the involvement of TLR3 signaling in the pathogenesis of T1D, and evaluate the efficacy of a potentially novel new drug for the treatment/prevention of T1D.