Hypertension and Collagen: Effect of Ac-SDKP

描述（由申请人提供）：高血压是心血管和肾脏疾病的主要危险因素。炎症和细胞外基质（EM）的成分对高血压中的终末靶器官（如动脉、心脏和肾脏）的生理和功能具有负面影响。阻断血管紧张素转换酶（ACE）可降低血管紧张素II（Ang II）并增加激肽，从而减少心血管炎症、肥大和胶原蛋白。ACE抑制剂（ACEi）增加血浆Ac-SDKP，一种存在于血浆和组织中的细胞增殖的负调节剂。在高血压和心力衰竭中，Ac-SDKP可防止主动脉、肾脏和左心室（LV）中的单核细胞/巨噬细胞浸润和纤维化。由于其抗纤维化和抗炎作用，Ac-SDKP能够改善高血压、糖尿病和其他肾脏疾病实验模型的肾功能。然而，Ac-SDKP的心血管和肾脏作用中涉及的机制或受体尚未完全了解。我们假设Ac-SDKP通过位于质膜上的特异性受体对高血压患者的心血管和肾脏系统发挥其抗炎和抗纤维化作用，有助于保护终末器官。在目的I中，我们将使用药理学工具[1]Hpp-Aca-SDKP、5（6）FAM-SDKP和Ac-SDKP的新类似物）、蛋白质组学技术和克隆技术鉴定和表征Ac-SDKP受体。在目标II中，我们将1）对Ac-SDKP的结构活性进行更广泛的检查，以便a）开发缺乏部分激动活性的强效拮抗剂和B）提高放射性碘化肽的亲和力;和2）表征成纤维细胞和巨噬细胞中的Ac-SDKP受体（大鼠和人）;和3）比较大鼠心脏成纤维细胞和人心脏成纤维细胞的Ac-SDKP或类似物对胶原合成和增殖的抑制作用。目的是研究Ac-SDKP受体活性是否依赖于与受体内化调节密切相关的机制。目的IV我们将确定1）Ac-SDKP对非受体酪氨酸激酶Src和HB-EGF对Ang II和ET-1刺激的EGFR反式激活的影响：2）Ac-SDKP是否抑制钙离子载体或EGF对p42/44 MAPK和胶原合成的作用; 3）PLC、EGFR、cSrc、钙调蛋白激酶或IP 3抑制剂是否与Ac-SDKP一样减弱MAPK活性和胶原合成，以响应Ang II或ET-1;和4）使用磷酸酶的选择性抑制剂和特异性siRNA，Ac-SDKP对MAP激酶活化的抑制是否由MAP激酶磷酸酶-1介导。该项目将为Ac-SDKP的作用机制提供重要的新信息。因此，它将确定另一种组分（Ac-SDKP）作为参与ACEi在高血压中的心脏保护作用的多种介质的一部分。

DESCRIPTION (provided by applicant): Hypertension is a major risk factor for .cardiovascular and renal diseases. Inflammation and components of the extracellular matrix (EM) have a negative impact on the physiology and function of end target organs such as the arteries, heart and kidneys in hypertension. Blocking angiotensin-converting enzyme (ACE) decreases angiotensin II (Ang II) and increases kinins, leading to decreased cardiovascular inflammation, hypertrophy and collagen. ACE inhibitors (ACEi) increase plasma Ac-SDKP, a negative regulator of cell proliferation present in plasma and tissue. In hypertension and heart failure, Ac-SDKP prevents monocyte/macrophage infiltration and fibrosis in the aorta, kidneys and left ventricle (LV). By virtue of its anti- fibrotic and anti-inflammatory effects, Ac-SDKP was able to improve renal function in hypertension, diabetes and other experimental models of renal diseases. However, the mechanism(s) or receptor(s) involved in Ac- SDKP's cardiovascular and renal effects are not fully understood. We hypothesize that Ac-SDKP exerts its anti-inflammatory and anti-fibrotic effects on the cardiovascular and renal systems in hypertension via specific receptor(s) located on the plasma membrane, contributing to end organ protection. In aim I we will identify and characterize Ac-SDKP receptors using pharmacological tools [ l]Hpp-Aca-SDKP, 5(6)FAM-SDKP and new analogues of Ac-SDKP), proteomic technology, and cloning techniques. In aim II we will 1) perform a more extensive examination of the structural activity of Ac-SDKP in order to a) develop potent antagonists that lack partial agonistic activity and b) improve the affinity of the radio-iodinated peptide; and 2) characterize the Ac-SDKP receptor in fibroblasts and macrophages (rat and human), using [ l]-Hpp- Aca-SDKP and newly developed antagonists; and 3) compare rat cardiac fibroblasts and human cardiac fibroblasts for the inhibitory effect of Ac-SDKP or analogues on collagen synthesis and proliferation. In aim we will study whether Ac-SDKP receptor activity depends on mechanisms closely linked to the regulation of receptor internalization. In aim IV We will determine 1) the effect of Ac-SDKP on the non-receptor tyrosine kinase Src and HB-EGF on Ang II and ET-1-stimulated transactivation of the EGFR; 2) whether Ac-SDKP inhibits the effects of calcium ionophores or EGF on p42/44 MAPK and collagen synthesis; 3) whether PLC, EGFR, cSrc, calmodulin kinase or IP3 inhibitors attenuate MAPK activity and collagen synthesis to the same extent as Ac-SDKP in response to Ang II or ET-1; and 4) whether inhibition of MAP kinase activation by Ac- SDKP is mediated by MAP kinase phosphatase-1, using selective inhibitors of phosphatases and specific SiRNAs. This project will provide important new information on the d the mechanism of action of Ac-SDKP. Consequently, it will identify another component (Ac-SDKP) as part of the multiple mediators participating in the cardioprotective effects of ACEi in hypertension.