In vivo probes for the APJ receptor.

 描述（由申请人提供）：本项目的目标是开发和测试用于先兆子痫（PE）相关体内研究的爱帕琳（APJ）受体探针。先兆子痫是一种复杂的孕产妇高血压疾病，约占所有妊娠的7-10%，每年全球约有100，000例孕产妇死亡。目前的治疗是不够的。先兆子痫与高血压和炎症有关，加上由于胎盘形成不足而导致的血管内皮功能受损，以及子宫胎盘灌注受损。这导致发育中的胎儿缺氧和血管生成平衡改变。G蛋白偶联受体（GPCR）蛋白APJ可能在PE中起调节作用。APJ在体内被循环但代谢不稳定的爱帕琳肽激活。APJ在包括胎盘在内的大多数器官的脉管系统中表达。APJ的激活促进血管舒张和血管生成。有趣的是，APJ基因敲除（ko）小鼠患有心力衰竭，表现出降低的血管生成潜力，并具有生殖缺陷（幼崽数量减少）。爱帕琳还在缺血的功能恢复期间诱导大血管的形成，缺血是一种缺氧和血管闭塞性疾病，如PE。我们在人类患者中发表的随访研究表明，血浆apelin浓度高的女性与血浆apelin浓度低的女性相比，PE的几率低48%。过去的研究还表明，局部apelin和APJ在人类PE患者的胎盘内上调，可能是一种代偿机制。因此，apelinergic系统应进行调查的机制，并在PE的背景下进行。然而，由于缺乏这种受体的药物样小分子配体，目前对APJ的体内研究很困难。迄今为止，我们的小组在这方面取得了重大进展。我们已经为APJ开发了适当的分析方法，并完成了一项筛选活动，以识别命中。这些化合物已被精制，以产生有效的APJ完全激动剂（EC 50 ~100 nM）。我们建议进一步完善这些化合物的药物样特性，使用迭代合成，评价和优化的药物样特性，使用电池的体外试验。选择的化合物将进行药代动力学（PK）测试，以鉴定用于体内测试的候选探针。我们假设APJ受体的优化探针将产生有益的抗高血压和促血管生成作用，同时降低PE临床前模型中的氧化应激。因此，化合物将在Sprague道利（SD）大鼠的先兆子痫的充分验证的、手术改变的子宫灌注压降低（RUPP）模型中进行评价，该模型再现了人类疾病的几种症状。将评价血压、血管生成平衡和氧化应激相关生物标志物。此外，将进行生殖毒理学分析，以排除不良反应。该项目的成功完成将导致新的APJ体内探针，这将使该受体在健康和疾病背景下的进一步研究成为可能。

 DESCRIPTION (provided by applicant): The goal of this project is to develop and test probes of the apelin (APJ) receptor for in vivo studies related to preeclampsia (PE). Preeclampsia is a complex maternal hypertensive disorder noted in ~7-10% of all pregnancies and accounts for ~100,000 maternal deaths globally each year. Current therapies are inadequate. Preeclampsia is linked to hypertension and inflammation, coupled with impaired vascular endothelial function due to inadequate placentation, and impaired utero-placental perfusion. This results in hypoxia and altered angiogenic balance within the developing fetus. The G-protein coupled receptor (GPCR) protein APJ may play a regulatory role in PE. APJ is activated by circulating but metabolically labile apelin peptides in vivo. APJ is expressed within the vasculature of most organs including placenta. Activation of APJ promotes vasodilation and angiogenesis. Interestingly, APJ knockout (ko) mice suffer from heart failure, demonstrate reduced angiogenic potential, and have reproductive deficiencies (reduced number of pups). Apelin also induces formation of large blood vessels during functional recovery from ischemia, which is a hypoxic and vaso- occlusive disorder like PE. Our published follow-up studies in human patients indicate that the odds of PE are 48% lower for women with high versus low plasma apelin concentration. Past studies also indicate that local apelin and APJ are up-regulated within the placentas of human PE patients perhaps as a compensatory mechanism. Thus, the apelinergic system should be investigated both mechanistically and pharmacologically within the context of PE. However, in vivo studies of APJ are difficult at the moment due to a paucity of available drug-like small molecule ligands of this receptor. To date, our group has made significant progress in this regard. We have developed appropriate assays for APJ and completed a screening campaign to identify hits. These compounds have been refined to produce full-agonist of APJ that are potent (EC50~100 nM). We propose to further refine the drug-like properties of these compounds using iterative synthesis, evaluation, and optimization of drug-like properties using a battery of in vitro assays. Select compounds will undergo pharmacokinetic (PK) testing to identify candidate probes for in vivo testing. We hypothesize that optimized probes of the APJ receptor will produce beneficial anti-hypertensive and pro-angiogenic effects while reducing oxidative stress in preclinical models of PE. Thus, compounds will be evaluated in a well-validated, surgically altered reduced uterine perfusion pressure (RUPP) model of preeclampsia in Sprague Dawley (SD) rats that reproduces several symptoms of the human disease. Blood pressure, angiogenic balance, and oxidative stress related biomarkers will be evaluated. Further, reproductive toxicological analyses will be performed to rule out adverse effects. Successful completion of this project will lead to new in vivo probes of APJ that will enable further studies of this receptor within the context of health and disease.