Role of TRPV channels in the pathogenesis of Systemic Sclerosis vasculopathy

描述(由申请人提供)：瞬时受体电位(Trp)通道是多模式受体阳离子通道的超家族，介导环境和感觉信号转导。Trp阳离子通道亚家族V(TrPV)成员对温度变化、渗透敏感性和应激等环境刺激非常敏感，它们的普遍表达表明它们在感觉和非感觉转导中都有作用。最近，我们做了一个极具挑衅性的观察，发现TRPV2在系统性硬化症(SSC)真皮成纤维细胞中的表达严重不足(超过20倍)，这表明TRPV通道可能在SSC的发病机制中发挥了作用。其他已发表的研究表明，在纤维化动物模型中，TRPV1和TRPV4参与了纤维化病变的发展。在这些研究的基础上，我们提出的假设是：在成纤维细胞和内皮细胞(EC)中，转化生长因子-β和TRPV通道建立了一个自分泌环路，其中转化生长因子-β的表达降低了TRPV1和TRPV2的表达，并诱导了TRPV4的表达。TRPV1和TRPV2的减少和TRPV4的增加反过来诱导和维持高水平的转化生长因子-β水平，形成一个重复的循环，触发静止的成纤维细胞的肌成纤维细胞分化，诱导内皮细胞向间充质转化(EndoMT)，导致进行性组织纤维化和纤维增生性血管病变。为了验证这一假说，我们将追求以下特定目标：特定目标1：检测在有无转化生长因子的存在和不存在的情况下，TRPV1、TRPV2和TRPV4激动剂和拮抗剂对人真皮成纤维细胞和人真皮和肺微血管内皮细胞中促纤维化基因和肌成纤维细胞激活相关基因表达的影响。特异性目的2：利用组织纤维化模型评价TRPV1、Trpv2和TRPV4基因敲除的体内效应。由于目前没有有效的疾病修正疗法来改善与SSC相关的破坏性健康后果和高死亡率，迫切需要确定潜在的目标来开发这种疗法。这一建议的优点是：1.强有力的初步数据表明，TRPV1和TRPV2的活性变化参与了成纤维细胞向激活的肌成纤维细胞的表型分化和诱导小鼠内皮细胞内毒素；以及2.它们将提供关于SSC中耦合感觉信号转导、炎症和纤维化的初始分子事件的有价值的信息。因此，我们认为这些研究可能为SSC的发病机制提供重要线索，并可能为这种目前无法治愈的疾病确定潜在的新治疗靶点。

DESCRIPTION (provided by applicant): Transient receptor potential (TRP) channels are a superfamily of polymodal receptor cation channels that mediate environmental and sensory signal transduction. TRP cation channel, subfamily V (TRPV) members are sensitive to various environmental stimuli such as: temperature changes, osmosensitivity and stress, and their ubiquitous expression suggests a role in both sensory and nonsensory transduction. Recently, we made the highly provocative observation that TRPV2 was profoundly underexpressed (greater than 20-fold) in Systemic Sclerosis (SSc) dermal fibroblasts compared to those from normal individuals, suggesting that TRPV channels may play a role in the pathogenesis of SSc. Other published studies have shown that TRPV1 and TRPV4 participate in the development of fibrotic lesions in animal models of fibrosis. Based on these studies we propose the hypothesis that: TGF-ß and TRPV channels establish an autocrine loop in fibroblasts and endothelial cells (EC) where TGF-ß expression decreases the expression of TRPV1 and TRPV2 and induces the expression of TRPV4. The reduction of TRPV1 and TRPV2 and the increase in TRPV4 in turn induce and maintain elevated TGF-ß levels creating a repetitive cycle which triggers myofibroblast differentiation in quiescent fibroblasts and induces endothelial to mesenchymal transition (EndoMT) in EC resulting in progressive tissue fibrosis and fibroproliferative vasculopathy. To test this hypothesis we will pursue the following Specific Aims: SPECIFIC AIM 1: Examine the effects of TRPV1, TRPV2 and TRPV4 agonists and antagonists in the presence and absence of TGF-ß, on the expression of profibrotic genes and of genes associated with myofibroblast activation in human dermal fibroblasts and with EndoMT in human dermal and pulmonary microvascular EC. SPECIFIC AIM 2: Evaluate the in vivo effects of Trpv1, Trpv2 and Trpv4 knockout employing the TGF-ß overexpression murine model of tissue fibrosis. Since there is currently no effective disease-modifying therapy to improve the devastating health consequences and high mortality associated with SSc, an urgent unmet need exists to identify potential targets to develop such therapies. The strengths of this proposal are: 1. It is supported by strong Preliminary Data demonstrating that alterations of the activity of TRPV1 and TRPV2 participate in the phenotypic differentiation of fibroblasts into activated myofibroblasts and in te induction of EndoMT in murine EC; and 2. They will provide valuable information regarding the initial molecular events that couple sensory signal transduction, inflammation and fibrosis in SSc. Thus, we believe these studies may provide important clues regarding SSc pathogenesis, and may identify potential novel therapeutic targets for this currently incurable disease.