Role of TRPV channels in the pathogenesis of Systemic Sclerosis vasculopathy

描述（由申请人提供）：瞬态受体电位（TRP）通道是介导环境和感觉信号转导的多模态受体阳离子通道的超家族。TRP阳离子通道亚家族V （TRPV）成员对各种环境刺激敏感，如温度变化、渗透敏感性和应激，它们的普遍表达表明它们在感觉和非感觉转导中都起作用。最近，我们发现TRPV2在系统性硬化症（SSc）真皮成纤维细胞中深度低表达（超过正常个体的20倍），这表明TRPV通道可能在SSc的发病机制中发挥作用。其他已发表的研究表明，在纤维化动物模型中，TRPV1和TRPV4参与纤维化病变的发展。基于这些研究，我们提出假设：TGF-ß和TRPV通道在成纤维细胞和内皮细胞（EC）中建立自分泌环，其中TGF-ß的表达降低TRPV1和TRPV2的表达，诱导TRPV4的表达。TRPV1和TRPV2的减少和TRPV4的增加反过来诱导并维持TGF-ß水平的升高，形成一个重复循环，在静止的成纤维细胞中触发肌成纤维细胞分化，在EC中诱导内皮细胞向间充质细胞转化（EndoMT），导致进行性组织纤维化和纤维增生性血管病变。为了验证这一假设，我们将追求以下具体目标：具体目标1：在TGF-ß存在和不存在的情况下，研究TRPV1、TRPV2和TRPV4激动剂和拮抗剂对人真皮成纤维细胞中与肌成纤维细胞激活相关的促纤维化基因和与人真皮和肺微血管EC中EndoMT相关的基因表达的影响。SPECIFIC AIM 2：通过TGF-ß过表达小鼠组织纤维化模型，评估敲除Trpv1、Trpv2和Trpv4的体内效应。由于目前没有有效的疾病修饰疗法来改善与SSc相关的破坏性健康后果和高死亡率，因此迫切需要确定开发此类疗法的潜在目标。该提案的优势在于：1。强有力的初步数据表明，TRPV1和TRPV2活性的改变参与成纤维细胞向活化的肌成纤维细胞的表型分化，并参与小鼠EC中EndoMT的诱导；和2。它们将为SSc中感觉信号转导、炎症和纤维化耦合的初始分子事件提供有价值的信息。因此，我们相信这些研究可能为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找到潜在的新治疗靶点。

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.