Membrane Serine Protease Activities in Protease Activated Receptor Signaling

描述（由申请人提供）：蛋白酶激活受体（PAR）是不同的G蛋白偶联受体（GPCR），允许细胞感知其环境中的特定蛋白酶。PAR正在成为几种疾病的有吸引力的治疗靶点，包括心血管疾病、关节炎、结肠炎、哮喘、神经退行性疾病和癌症。单个PAR能够激活赋予屏障破坏性促炎信号传导以及抗炎屏障保护性信号传导途径的途径。这种选择性信号传导是如何介导的知之甚少，并且代表了开发用于治疗用途的靶向PAR的有效激动剂和拮抗剂的重大障碍。更好地了解蛋白酶环境的性质，诱导差异PAR信号，参与蛋白酶激活PAR的分子机制是至关重要的。我们已经发现，两种膜锚定丝氨酸蛋白酶，睾丸素和间质蛋白酶，是PAR 2的细胞特异性内源性激活剂，并可能分别调节内皮细胞和上皮细胞中PAR 2的局部空间和时间信号传导。我们的数据表明，GPI锚定的丝氨酸蛋白酶，睾丸素，是一种促血管生成因子，可以激活PAR 2在微血管，促进毛细血管生长的血管生成的重要。我们还发现，跨膜丝氨酸蛋白酶，间质蛋白酶，可以维持PAR 2依赖性信号通路的重要维持肠上皮屏障。该研究计划的目标是确定这些PAR 2激活膜丝氨酸蛋白酶的活性，并开发一种新的前药策略，用于检测和靶向其活性。研究计划将利用体外培养物与小鼠体内研究相结合，以检测以下目的：1）确定睾丸素对血管生成期间PAR 2信号传导的贡献，2）确定PAR在调节前列腺素->间质蛋白酶介导的肠上皮屏障关闭中的调节作用，和3）重新设计炭疽毒素以靶向细胞表面上的PAR 2活化膜锚定丝氨酸蛋白酶。

DESCRIPTION (provided by applicant): Protease-activated receptors (PARs) are distinct G protein-coupled receptors (GPCRs) that allow cells to sense specific proteases in their environment. PARs are emerging as attractive therapeutic targets for several diseases, including cardiovascular diseases, arthritis, colitis, asthma, neurodegenerative conditions and cancer. Individual PARs are able to activate pathways that confer both barrier disruptive, proinflammatory signaling, as well as anti-inflammatory barrier protective signaling pathways. How this selective signaling is mediated is poorly understood, and represents a significant impediment to the development of effective agonists and antagonists targeting PARs for therapeutic uses. A better understanding of the nature of the protease environment that induces differential PAR signaling, and the molecular mechanisms involved in protease activation of PARs are critical. We have discovered that two membrane-anchored serine proteases, Testisin and Matriptase, are cell-specific endogenous activators of PAR2, and likely modulate localized spatial and temporal signaling of PAR2 in endothelial and epithelial cells, respectively. Our data suggests that the GPI anchored serine protease, Testisin, is a proangiogenic factor that can activate PAR2 in the microvasculature, and facilitate capillary growth important for angiogenesis. We also find that the transmembrane serine protease, Matriptase, may sustain a PAR2 dependent signaling pathway important for maintaining the intestinal epithelial barrier. The goal of the research plan is to define the activities of these PAR2-activating membrane serine proteases and to develop a novel prodrug strategy for both detecting and targeting their activities. The research plan will utilize in vitro cultures in concert with in vivo studies in mic to test the following aims: 1) to determine the contribution of Testisin to PAR2 signaling during angiogenesis, 2) to determine the role of PARs in regulating in regulating Prostasin->Matriptase mediated intestinal epithelial barrier closure, and 3) to reengineer anthrax toxins to target PAR2-activating membrane-anchored serine proteases on the cell surface.