SHH信号通路抑制剂调控BMP信号通路改善肺血管重构的机制研究

Recent researches and our pretest studies revealed that SHH-PTC-GLI1 signaling support a major role in the pathogenesis of pulmonary arterial hypertension (PAH). However, whether inhibition of SHH pathway could attenuate pulmonary vascular remodeling and the mechanisms by which SHH inhibitor and bone morphogenetic protein receptor type II (BMPR-II) dysfunction conspire to improve disease remain unknown. We therefore hypothesized that SHH inhibitor could attenuate pulmonary vascular remodeling via regulating the uncontrolled proliferation, resistance to apoptosis and disordered phenotypic transformation of pulmonary arterial smooth muscle cells (PASMCs). Moreover, we hypothesized that SHH inhibitor had therapeutic effects in pulmonary arterial hypertension by influencing the BMP2/4-BMPR-Smad1/5/8-ID/RUNX pathway. Furthermore, we want to investigate whether the SHH inhibitor could attenuate the dysfunction of proliferation and apoptosis in BMPR-II deficient human pulmonary arterial smooth muscle cells (hPASMCs) through the activation of TGFβ-TGFβR-ALK5-Smad4 pathway. In this study, the therapeutic effect of SHH inhibitor were measured in the rodent lung tissue of monocrotaline induced PAH models and isolated PASMCs from rats. The effects of SHH inhibitor on BMPR-II deficiency and associated mechanisms will be tested in hPASMC. In conclusion, our data try to provide evidence that SHH inhibitor plays a role in pulmonary vascular remodeling and it could be a potential therapeutic target for PAH.

之前研究及本课题组预实验均提示SHH-PTC-GLI1信号通路参与肺动脉高压的发生，但SHH信号通路抑制剂环杷明（Cyclopamine, Cy）是否能够改善肺血管重构及其调控机制尚不清楚。我们研究内容如下：（1）讨论Cy是否通过肺动脉平滑肌细胞的增值/凋亡/表型转化而改善肺血管重构，预防并治疗肺动脉高压；（2）讨论Cy是否通过影响BMP2/4-BMPR-Smad1/5/8-ID/RUNX信号通路，调控肺血管重构；（3）讨论Cy是否对BMPR-II基因突变的hPASMC同样起到治疗作用，其机制是否为激活TGFβ-TGFβR-ALK5-Smad4途径。本研究将从原代培养的肺动脉平滑肌细胞及野百合碱诱导的肺动脉高压动物模型两个方面验证我们的假设，并探讨其分子生物学机制。目前部分SHH信号通路抑制剂已作为抗肿瘤药物进入Ⅱ期临床阶段，本研究将为肺高压的治疗及合理用药提供理论基础及实验依据。

肺动脉高压(Pulmonary arterial hypertension, PAH)是一类严重的渐进性疾病，其中肺血管重构是发病的重要原因。很多PAH患者存在BMPR2（morphogenetic protein receptor type2,BMPR2）相关信号通路的异常。之前研究及本课题组预实验均提示SHH-PTC-GLI1信号通路参与肺动脉高压的发生。而在其他疾病中，提示存在BMP信号通路与SHH信号通路的相互作用。但SHH信号通路抑制剂环杷明（Cyclopamine, Cy）是否能够改善肺血管重构及其调控机制尚不清楚。基于以上的背景和基础，本项目组有如下发现：（1）环杷明药物处理能够降低右心室收缩压、改善右心肥大指数，在一定程度上治疗肺动脉高压。（2）环杷明药物处理能通过调节肺动脉平滑肌细胞的增殖/凋亡异常，改善平均血管厚度、平均血管面积及肺动脉肌化程度，缓解肺血管重构；（3）环杷明药物处理能够通过影响BMP4-BMPR-Smad1/5/8-ID2信号通路，调控肺血管重构，治疗肺动脉高压；（4）环杷明药物处理对BMPR2基因缺陷的hPASMC同样存在治疗作用，其机制考虑为激活TGFβ-TGFβR-ALK1- Smad1/5/8途径。综上所述，本研究将从原代培养的人肺动脉平滑肌细胞及野百合碱诱导的肺动脉高压动物模型两个方面，明确环杷明对PAH发病的治疗作用，可以通过调节BMP4-BMPR-Smad1/5/8-ID2信号通路，改善肺血管重构实现的。目前部分SHH信号通路抑制剂已作为抗肿瘤药物进入Ⅱ期临床阶段，本研究将为肺高压的治疗及合理用药提供理论基础及实验依据。