Serotonin and the Rho Signaling Pathway in Smooth Muscle Cells

描述（由申请方提供）：临床、动物实验和人类遗传信息目前支持5-羟色胺（5- HT）与肺动脉高压（PH）的关系。我们等的研究表明，5- HT转运体（5-HTT）和5-HT受体（5-HTRs）在肺血管平滑肌细胞（SMC）对5-HT的增殖反应中起重要作用。我们已经确定了协同行动的5-HTT和5-HTR通过独立的刺激信号通路的增殖反应。MARK通过5-HTT被激活，并且通过5-HT 1B激活Rho通路参与MARK从SMC细胞质到细胞核的移位。最近，我们还发现5-HT可反式激活PDGF受体（R），酪氨酸激酶抑制剂Gleevec对这种激活的干扰可阻断5-HT诱导的SMC增殖。Rho通路在5-HT诱导的SMC增殖中起着核心作用，并已报道参与缺氧诱导的PH;重要的是，目前可使用药物来修饰该通路。我们假设Rho通路的激活和PDGFR的反式激活参与SMC的增殖和迁移过程中的重要发展的PH。我们希望在这个建议，以更好地研究5-HT相关的信号通路，在体外和体内，编排SMC的增殖和迁移。为此，我们计划：1）进一步确定5-HT诱导的SMC增殖和迁移的Rho信号的上下游效应物; 2）确定他汀类药物和其他香叶基香叶基和法尼基转移酶抑制剂对5-HT诱导的SMC反应的作用和作用机制; 3）评价5-HT反式激活PDGFR在SMC增殖和迁移反应中的作用;和4）使用暴露于缺氧并通过渗透泵输注5-HT的野生型和5-HTT和5-HTR转基因小鼠，将体外发生的信号传导途径与体内有效的信号传导途径相关联。我们相信整个实验将提供一个更好的评价5-HT相关的细胞信号通路，可能是在PH操作，并可能允许新的方法来治疗这种疾病。

DESCRIPTION (provided by applicant): Clinical, animal experimental and human genetic information currently support a relationship of serotonin ( 5- HT) to pulmonary hypertension (PH). Studies by us and others have indicated the importance of both the 5- HT transporter (5-HTT) and 5-HT receptors (5-HTRs) in the pulmonary vascular smooth muscle cell (SMC) proliferative response to 5-HT. We have identified collaborative actions of the 5-HTT and 5-HTRs through independent stimulations of signaling pathways in the proliferative response. MARK is activated through the 5-HTT and activation of the Rho pathway via 5-HT 1B participates in translocation of MARK from SMC cytoplasm to nucleus. More recently, we have also found that 5-HT transactivates the PDGF receptor (R) and interference of this activation by Gleevec, a tyrosine kinase inhibitor, blocks 5-HT-induced SMC proliferation. The Rho pathway plays a central role in 5-HT-induced SMC proliferation and has been reported to participate in hypoxia-induced PH; importantly, agents are currently available to modify this pathway. We hypothesize that activation of the Rho pathway and transactivation of PDGFR participate in SMC proliferative and migratory processes important in development of PH. We wish in this proposal to better study the 5-HT-related signaling pathways in vitro and in vivo that orchestrate SMC proliferation and migration. To do this we plan to: 1) Further define upstream and downstream effectors of 5-HT-induced Rho signaling in SMCs in culture that lead to SMC proliferation and migration; 2) Determine the effect and mechanisms of action of statins and other geranylgeranyl and farnesyl transferase inhibitors on the 5-HT- induced SMC responses; 3) Evaluate the role of transactivation of PDGFR by 5-HT in SMC proliferative and migratory responses; and 4) Correlate the signaling pathways occurring in vitro with those operative in vivo with the use of wild type and 5-HTT and 5-HTR transgenic mice exposed to hypoxia and infused with 5-HT by osmotic pumps. We believe the overall experiments will provide a better appreciation of 5-HT-related cell signaling pathways that may be operative in PH and may allow new approaches to therapy of this disease.