Novel Peptide for Dynamic Regulation of Lung Endothelium NOS/cGMP Functions

描述(申请人提供)：肺动脉高压(PAH)的特征是血管阻塞和不同程度的血管收缩，导致肺血管阻力增加和右室衰竭。尽管其严重的临床后果是高发病率和高死亡率，但过去20年的治疗进展略微改善了PAH患者的存活率。联合使用现有药物以最大限度地发挥临床效益是治疗PAH的一种新兴策略。肺血管内皮细胞一氧化氮合酶(ENOS)来源的NO是肺循环中产生环鸟苷(CGMP)和依赖NO/cGMP的血管松弛的主要刺激物。另外，肺血管cGMP水平也可以通过抑制磷酸二酯酶5(PDE5)来提高，以达到类似的反应。我们最近报道了一种11个氨基酸(SSWRRKRKESS)合成肽(P1)能刺激eNOS的催化活性，并在离体肺动脉(PA)节段和肺灌流模型上引起依赖NO/cGMP的持续血管松弛。最近的初步数据表明，P1刺激增加了细胞内NO的释放，并抑制了肺动脉内皮细胞中cGMP特异性的PDE5。根据我们以前的报道和初步研究，我们假设P1治疗作为一种NO释放的PDE5抑制剂的独特的双重作用，可以作为治疗PAH的一种新的治疗方法。为了验证这一假说，本研究旨在：1)建立与生理相关的PAH临床前动物模型，重点评估生物利用度、给药方案和P1治疗对血流动力学、组织学和生化变化的疗效；2)确定与P1介导的小窝蛋白-1/eNOS解离和eNOS激活相关的特定分子事件，以及P1对PDE5活性和cGMP水解酶的影响。我们预计，在临床前动物模型中证实这种新的治疗性多肽的基于机制的双重作用将促进P1治疗PAH的I期临床试验。

DESCRIPTION (provided by applicant): Pulmonary arterial hypertension (PAH) is characterized by vascular obstruction and variable presence of vasoconstriction, leading to increased pulmonary vascular resistance and right ventricular failure. Despite its profound clinical consequences with high morbidity and mortality, therapeutic advances over the past 20 years have modestly improved survival of PAH patients. The combined use of available drugs to maximize the clinical benefit is an emerging strategy for the treatment of PAH. Pulmonary vascular endothelial nitric oxide (NO) synthase (eNOS)- derived NO is the major stimulant of cyclic guanosine 5' monophosphate (cGMP) production and NO/cGMP-dependent vasorelaxation in the pulmonary circulation. Alternatively, pulmonary vascular cGMP levels can also be elevated via inhibition of phosphodiesterase type 5 (PDE5) to achieve a similar response. We recently reported that an eleven amino acid (SSWRRKRKESS) synthetic peptide (P1) stimulates the catalytic activity of eNOS and causes NO/cGMP-dependent sustained vasorelaxation in isolated pulmonary artery (PA) segments and in lung perfusion models. More recent preliminary data suggest that P1 stimulation increases intracellular NO release and inhibits cGMP-specific PDE5 in pulmonary artery endothelial cells. Based on our earlier report and preliminary studies we hypothesize that P1 treatment with its unique dual action as a NO-releasing PDE5 inhibitor can be used as a novel therapeutic approach for the treatment of PAH. To test this hypothesis, the present study is designed to: 1) develop a physiologically relevant preclinical animal model of PAH with specific focus on assessment of bioavailability, dosing regimen, and efficacy of P1 therapy on the hemodynamic, histologic, and biochemical changes, and 2) identify the specific molecular events associated with P1-mediated caveolin-1/eNOS dissociation and activation of eNOS as well as the effects of P1 on PDE5 activity and cGMP hydrolysis. We anticipate that confirmation of mechanism-based dual action of this novel therapeutic peptide in a preclinical animal model will facilitate Phase I clinical trials for P1 treatment of PAH.