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）通道是介导环境和感觉信号转导的多模态受体阳离子通道超家族。TRP阳离子通道V亚家族（TRPV）成员对各种环境刺激如温度变化、温度敏感性和应激敏感，并且它们的普遍表达暗示了在感觉和非感觉转导中的作用。最近，我们进行了高度挑衅性的观察，即TRPV 2在系统性硬化症（SSc）皮肤成纤维细胞中的表达低于正常人，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，TRPV 1和TRPV 4参与纤维化动物模型中纤维化病变的发展。基于这些研究，我们提出以下假设：TGF-β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-β表达降低TRPV 1和TRPV 2的表达并诱导TRPV 4的表达。TRPV 1和TRPV 2的减少以及TRPV 4的增加进而诱导并维持升高的TGF-β 1水平，从而产生重复循环，其触发静止成纤维细胞中的肌成纤维细胞分化并诱导EC中的内皮向间充质转化（EndoMT），导致进行性组织纤维化和纤维增生性血管病。具体目的1：检测在存在和不存在TGF-β的情况下TRPV 1、TRPV 2和TRPV 4激动剂和拮抗剂对促纤维化基因和与人真皮成纤维细胞中的肌成纤维细胞活化相关的基因以及与人真皮和肺微血管EC中的EndoMT相关的基因的表达的影响。具体目的2：使用组织纤维化的TGF-β过表达鼠模型评价Trpv 1、Trpv 2和Trpv 4敲除的体内作用。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靶标。该建议的优点是：1。这得到了强有力的初步数据的支持，表明TRPV 1和TRPV 2活性的改变参与了成纤维细胞向活化的肌成纤维细胞的表型分化，并参与了小鼠EC中EndoMT的诱导;和2.他们将提供有价值的信息，关于耦合感觉信号转导，炎症和纤维化的SSc的初始分子事件。因此，我们相信这些研究可能提供有关SSc发病机制的重要线索，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.