Unveiling the role of G-protein-coupled receptors in Pulmonary Hypertension

揭示G蛋白偶联受体GPRC5B、P2Y2、GPR4和GPR21在肺动脉高压发生和治疗中的作用。G蛋白偶联受体(GPCRs)在心肺疾病的治疗中发挥着重要的作用，有1000多个不同的成员，是最大的蛋白质超家族。肺动脉高压(PAH)是一种肺血管疾病，它改变了所有的血管层，增加了肺动脉压(PAP)，如果不治疗，在晚期会导致右心衰竭，从而导致死亡。过去已经开发了许多药物来作为多环芳烃中GPPCRs的激动剂或拮抗剂。在对PAH患者的细胞和组织的初步研究中，我们发现了新的差异调控的GPCRs，其在这一应用中的作用有待进一步研究。利用GPCR微阵列和测序研究，我们确定了四个新的GPCR(GPRC5B、GPR4、GPR21和P2Y2)和三个G蛋白(GNA11、GNA14和GNG2)，这些蛋白在患者中发生了显著变化，但尚未在PAH研究中进行研究。到目前为止，我们已经对嘌呤能受体P2Y2在人肺血管内皮细胞和平滑肌细胞(HPAECs或HPASMCs)中的作用进行了初步研究。内皮细胞中的P2Y2受体参与了NO分泌的增加，而其特异性激动剂(MRS2768)对肺平滑肌细胞中P2Y2的激活抑制了IPAH-HPASMCs的增殖率，因此有待进一步研究。受体GPRC5B、GPR4和GPR21的功能是最近才被证实的，它们的特异性配体在肺动脉高压领域还没有被研究过，可以用于进一步的研究(化合物3b和GRA2)。除了GNA11、GNA14及其配体(FR900359、YM-254890和WU-07047)外，还有4个有希望的GPCRs及其配体(无配体的GPRC5B、GPR4及其化合物3b、GPR21及其配体GRA2以及P2Y2及其配体MRS2768)将在体外和体外(离体肺内动脉环、离体小鼠肺灌流)中进行研究。体内方法将考虑内皮和平滑肌特异性诱导的P2Y2和GPRC5B基因敲除小鼠，以找出它们在肺血管不同细胞层中的作用。总之，据我们所知，这项研究将是对PAH-G蛋白和PAH-GPCRs的第一次全面研究，以期为PAH患者提供更多的了解、更好的条件和新的治疗方法。

Unveiling the role of the G protein-coupled receptors GPRC5B, P2Y2, GPR4, and GPR21 in the development and treatment of pulmonary hypertension. G-protein coupled receptors (GPCRs) play a prominent role in the therapy of cardiopulmonary diseases and, with over 1000 different members, represent the largest protein superfamily. Pulmonary arterial hypertension (PAH) is a disease of the pulmonary vessels that alters all vascular layers and increases the pulmonary artery pressure (PAP) leading in late stages, if not treated, to the right heart failure and consequently the death. Numerous drugs have been developed in the past to act as agonists or antagonists of GPPCRs in PAH. In initial studies on human cells and tissues from PAH patients, we identified new differentially regulated GPCRs, the role of which is to be further investigated in this application. Using GPCR-specific microarrays and sequencing studies, we identified four new GPCRs (GPRC5B, GPR4, GPR21, and P2Y2) and three G proteins (GNA11, GNA14, and GNG2) that are significantly changed in patients and yet have not been investigated in PAH research. So far, we have carried out our initial studies on the role of the purinergic receptor P2Y2 in human pulmonary arterial endothelial and smooth muscle cells (HPAECs or HPASMCs). The endothelial P2Y2 receptor is involved in increased NO secretion, whereas the activation of P2Y2 in the pulmonary smooth muscle cells with its specific agonist (MRS2768) attenuates the proliferation rate of the IPAH-HPASMCs and should be therefore further investigated. The function of the receptors GPRC5B, GPR4, and GPR21 has only recently been demonstrated and their specific ligands, which have not yet been investigated in the field of pulmonary hypertension, are available for further investigations (compound 3b and GRA2). The four promising GPCRs and their ligands (GPRC5B without ligands, GPR4 and its compound 3b, GPR21 and its ligand GRA2 as well as P2Y2 and its ligand MRS2768) in addition to GNA11, GNA14, and their ligands (FR900359, YM-254890, and WU-07047) will be investigated in invitro and ex-vivo (isolated intrapulmonary arterial rings, isolated perfused mouse lungs). The in-vivo approach will consider endothelial- and smooth muscle-specific induced knockout mice of P2Y2 and GPRC5B to figure out their role in the different cell layers of pulmonary vessels. In summary, due to our best knowledge, this study would be the first comprehensive study for PAH-G proteins and PAH-GPCRs towards more understanding, better conditions, and new treatment for PAH patients.