JAK1/2 as a Central Regulator of iMCD Pathogenesis and Novel Therapeutic Target

项目摘要/摘要： 人类疱疹病毒(HHV)-8阴性的特发性多中心Castleman病(IMCD)是一种致命的血液病 涉及多克隆淋巴增殖和多器官系统功能障碍的疾病。IMCD被诊断为 在美国，每年大约有1500人；35%的人在5年内死亡。有限的选择存在于 西尔图昔单抗阻断白介素6(IL-6)无效的66%患者接受细胞毒化疗； 复发是很常见的。病因、病理细胞类型和失调的信号通路很差。 明白了。为了找到新的治疗方法，有必要提高对疾病机制的理解。 在之前的资助周期中，我们证明了IMCD患者表现出mTOR信号在 淋巴结节和循环中激活的T细胞。西罗莫司抑制mTOR信号转导通路 活化的T细胞和部分患者的临床改善。然而，导致增加的信号 MTOR激活和参与治疗难治性患者的替代途径仍不清楚。我们 认为免疫系统中细胞因子信号转导异常可能是mTOR信号转导增加的原因 IMCD中的细胞和炎症反应。我们最近的初步数据表明，IMCD患者的T细胞在 在I型刺激下，缓解显示pS6表达增加，这是mTOR激活的读出 干扰素(IFN-I)和IL-6与健康对照组比较。鉴于干扰素-I和IL-6通过JAK1和JAK2发出信号， 我们推测，JAK1/2的抑制可以消除IL-6和干扰素-2诱导的mTOR激活增加。 事实上，在体外，Ruxolitinib对JAK1/2的抑制可以消除IMCD患者T细胞中mTOR活性的增加 细胞。基于这些体外结果和蛋白质组学数据表明JAK-STAT3信号在 对于IMCD患者，我们使用Ruxolitinib治疗一名高度治疗难治性和危重的儿童IMCD患者， 她已经完全缓解了24个月，比她以前的平均缓解期长了20倍。 我们假设JAK1/2信号是mTOR激活和IMCD的中心调节因子 发病机制中，JAK介导的细胞因子刺激超敏是其机制基础，而Ruxolitinib 通过抑制JAK1/2、T细胞活化和mTOR来阻断IMCD。在目标1中，我们将研究JAK1/2的激活 和mTOR信号在IMCD患者样本中的表达。在目标2中，我们将严格评估IMCD患者 T细胞对细胞因子干扰素-I和白介素6的体外应答及其相互作用机制 JAK1/2和mTOR信号转导。根据我们的初步数据，我们假设IRS1的磷酸化 JAK1/2下游可导致PI3K/AKT和mTOR激活。目标3概述了对 Ruxolitinib在IMCD患者体内研究JAK1/2信号转导。拟议的研究将会取得进展 了解IMCD的信号转导途径和细胞类型，可能会导致新的治疗方法 IMCD和相关疾病的范例。使用临床和发现数据揭示现有的 对于没有FDA批准的疗法的95%的罕见疾病，药物是确定治疗方法的关键。

Project Summary/Abstract: Human herpesvirus(HHV)-8-negative, idiopathic multicentric Castleman disease (iMCD) is a deadly hematologic illness involving polyclonal lymphoproliferation and multiple organ system dysfunction. iMCD is diagnosed in approximately 1,500 individuals annually in the USA; 35% die within 5 years. Limited options exist beyond cytotoxic chemotherapies for the 66% of patients refractory to interleukin-6 (IL-6) blockade with siltuximab; relapse is common. The etiology, pathological cell types, and dysregulated signaling pathways are poorly understood. Improved understanding of disease mechanisms is necessary to identify new treatments. In the previous funding cycle, we demonstrated that iMCD patients display increased mTOR signaling in lymph nodes and activated T cells in circulation. Inhibiting mTOR signaling with sirolimus led to a decrease in activated T cells and clinical improvement in a subset of patients. However, the signals leading to increased mTOR activation and alternative pathways involved in treatment-refractory patients remain unknown. We propose that dysregulated cytokine signaling could be responsible for the increased mTOR signaling in immune cells and hyperinflammation in iMCD. Our recent preliminary data suggest that T cells from iMCD patients in remission display increased pS6 expression, a read-out of mTOR activation, upon stimulation with Type I interferon (IFN-I) and IL-6 compared to healthy controls. Given that IFN-I and IL-6 signal through JAK1 and JAK2, we hypothesized that JAK1/2 inhibition could abrogate the increased mTOR activation induced by IL-6 and IFN- I. Indeed, in vitro JAK1/2 inhibition by ruxolitinib abrogated the increased mTOR activation in iMCD patient T cells. Based on these in vitro results and proteomics data indicating enrichment of JAK-STAT3 signaling across iMCD patients, we administered ruxolitinib to a highly treatment refractory and critically ill pediatric iMCD patient, who has been in complete remission for 24 months, 20-fold longer than her previous average remission duration. We hypothesize that JAK1/2 signaling is a central mediator of mTOR activation and iMCD pathogenesis, JAK-mediated hypersensitivity to cytokine stimulation is the mechanistic basis, and ruxolitinib interrupts iMCD by inhibiting JAK1/2, T cell activation, and mTOR. In Aim 1, we will study the activation of JAK1/2 and mTOR signaling in iMCD patient samples during flare. In Aim 2, we will rigorously evaluate how iMCD patient T cells respond to cytokine stimulation with IFN-I and IL-6 in vitro and establish the mechanistic link between JAK1/2 and mTOR signaling. Based on our preliminary data, we hypothesize that IRS1 phosphorylation downstream of JAK1/2 can lead to PI3K/AKT and mTOR activation. Aim 3 outlines a mechanistic study of ruxolitinib in iMCD patients to investigate JAK1/2 signaling in vivo. The proposed studies will advance understanding of dysregulated signaling pathways and cell types in iMCD and may lead to a new treatment paradigm for iMCD and related disorders. Using clinical and discovery data to uncover a novel use for an existing drug is critical to identify therapies for the 95% of rare diseases with no FDA-approved therapy.