In vivo probes for the APJ receptor.

 描述(申请人提供)：该项目的目标是开发和测试apelin(APJ)受体的探针，用于与子痫前期(PE)相关的体内研究。子痫前期是一种复杂的孕产妇高血压疾病，占所有妊娠的7%-10%，全球每年约有10万名孕产妇死亡。目前的治疗方法是不够的。先兆子痫与高血压和炎症有关，再加上由于胎盘不充分造成的血管内皮功能受损，以及子宫-胎盘灌注受损。这会导致缺氧，并改变发育中的胎儿的血管生成平衡。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apelin多肽激活。APJ在包括胎盘在内的大多数器官的血管系统中表达。APJ的激活促进血管扩张和血管生成。有趣的是，APJ基因敲除(KO)小鼠患有心力衰竭，表现出血管生成潜力降低，并有生殖缺陷(幼崽数量减少)。Apelin还可以在缺血后的功能恢复过程中诱导大血管的形成，这是一种类似于PE的缺氧性和血管闭塞性疾病。我们发表的对人类患者的随访研究表明，血浆apelin浓度高的女性发生PE的几率比低血浆apelin浓度的女性低48%。过去的研究也表明，局部apelin和apj在人类PE患者胎盘中表达上调，可能是一种代偿机制。因此，应该在PE的范围内从机制和药理学两方面来研究apeline能系统。然而，目前对APJ受体的体内研究很困难，因为这种受体的可用药物样小分子配体很少。迄今为止，我们小组在这方面取得了重大进展。我们已经为APJ开发了适当的检测方法，并完成了一项识别Hit的筛查活动。这些化合物已被精制成有效的APJ全激动剂(EC50~100 nM)。我们建议通过迭代合成、评估和优化使用一组体外测试的类药物特性来进一步提炼这些化合物的类药物特性。选定的化合物将接受药代动力学(PK)测试，以确定用于体内测试的候选探针。我们假设，APJ受体的优化探针将在临床前PE模型中产生有益的降压和促血管生成作用，同时减少氧化应激。因此，化合物将在一种经过良好验证的、经手术改变的降低子宫灌流压力(RUPP)的先兆子痫大鼠模型中进行评估，该模型再现了人类疾病的几种症状。将评估与血压、血管生成平衡和氧化应激相关的生物标记物。此外，将进行生殖毒理学分析，以排除不良影响。该项目的成功完成将导致对APJ的新的活体探测，这将使在健康和疾病背景下对该受体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.