Role of LMPTP in cardiac fibrosis

项目摘要 本提案的目的是确定低分子量蛋白的作用机制 酪氨酸磷酸酶（LMPTP）在心脏纤维化中的作用。 心脏纤维化是心力衰竭发病机制的主要贡献者。在心脏组织中，纤维化促使 包括扩张和肥大的病理变化，并最终导致心力衰竭。没有 FDA批准的用于心力衰竭的抗纤维化药物;因此， 这是心脏病学中一个主要的未满足的医疗需求。 该提案的重点是酪氨酸磷酸酶LMPTP，这是由ACP 1基因编码。LMPTP具有 被认为是通过酪氨酸去磷酸化的受体酪氨酸激酶的信号传导抑制剂 它们的激活基序中的残基。在人类中，ACP 1基因的遗传多态性编码高 已知LMPTP活性促进心肌肥大。我们先前报道了LMPTP表达， 在患有终末期心力衰竭的人的心脏中显著上调。我们生成了第一个LMPTP 基因敲除小鼠，并发现当通过横向主动脉收缩使血压超负荷时， (TAC)，它们受到保护免于心脏肥大和衰竭，并在 心脏我们还发现，用我们开发的小分子化学抑制剂抑制LMPTP 导致TAC治疗小鼠的心脏纤维化、肥大和衰竭减少。总的来说，这些发现 提示LMPTP作为心脏纤维化和衰竭促进剂的新作用。 在这里，我们提出了一系列的机制实验，以阐明生理和分子 LMPTP在纤维化相关心力衰竭中的作用机制。我们将（目标1）证明LMPTP 在多种小鼠模型中促进心脏纤维化，（目的2）确定LMPTP促进心脏纤维化的细胞类型。 目的3：探讨LMPTP促进心肌纤维化的分子机制 纤维化和衰竭。

PROJECT SUMMARY The objective of this proposal is to determine the mechanism of action of the low molecular weight protein tyrosine phosphatase (LMPTP) in cardiac fibrosis. Cardiac fibrosis is a major contributor to the pathogenesis of heart failure. In cardiac tissue, fibrosis prompts pathological changes that include dilation and hypertrophy, and ultimately leads to heart failure. There are no FDA-approved anti-fibrotic medications for heart failure; therefore, novel agents to alleviate cardiac fibrosis are a major unmet medical need in cardiology. This proposal focuses on the tyrosine phosphatase LMPTP, which is encoded by the ACP1 gene. LMPTP has been considered an inhibitor of signaling through receptor tyrosine kinases by dephosphorylation of tyrosine residues in their activation motifs. In humans, genetic polymorphisms in the ACP1 gene encoding for high LMPTP activity are known to promote myocardial hypertrophy. We previously reported that LMPTP expression is significantly upregulated in hearts of humans with end-stage heart failure. We generated the first LMPTP knockout mice and found that when subjected to blood pressure overload through transverse aortic constriction (TAC), they are protected from cardiac hypertrophy and failure, and develop substantially decreased fibrosis in the heart. We also found that inhibiting LMPTP with a small-molecule chemical inhibitor that we developed leads to reduced cardiac fibrosis, hypertrophy, and failure in TAC-treated mice. Taken together, these findings suggest a novel role for LMPTP as a promoter of cardiac fibrosis and failure. Here we propose a series of mechanistic experiments to elucidate the physiological and molecular mechanisms of action of LMPTP in fibrosis-associated heart failure. We will (Aim 1) demonstrate that LMPTP promotes cardiac fibrosis in multiple mouse models, (Aim 2) determine the cell type by which LMPTP promotes cardiac fibrosis, and (Aim 3) determine the molecular mechanism of action of LMPTP in promoting cardiac fibrosis and failure.