血管组织神经肽ACTH在高血压诱导血管重建中的力学生物学作用及其机制

The changed proliferation and apoptosis of endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), which are induced by the mechanical stimuli, play important roles in vascular remodeling during hypertension. Our previous work revealed that the expression of adrenocorticotropic hormone (ACTH), a kind of neuropeptide, was significantly increased in the artery of hypertensive rat, but the mechano-biological mechanism of highly-expressed ACTH in the vascular remodeling during hypertension is still unclear. In our present project, the relationship between vascular remodeling caused by hypertension and expression of ACTH and its receptor expressed at aorta will be firstly evaluated by using hypertensive animal model. Then using the cyclic strain FX-4000T system, how ACTH modulates the proliferation and apoptosis of ECs and VSMCs under different magnitudes of cyclic strain will be further investigated in vitro. Based on the transcriptional mechanism analyzed in vitro, the molecular mechanism of ACTH and its receptor in vascular remodeling during hypertension will be detected by using ECs or VSMCs specific gene knock-out mice. Furthermore, the antagonists and agonists of vascular ACTH receptor, respectively, will be used to evaluate the possible therapeutic effect of vascular ACTH system on hypertension. Our project intends to demonstrate the mechanical mechanism of ACTH, expressed at artery, on vascular remodeling during hypertension. The research may give some new insights into understanding the molecular mechanism of vascular remodeling induced by hypertension, and may provide some new targets for clinical therapy of hypertension.

异常应力（应变）刺激诱导的血管内皮细胞（ECs）和平滑肌细胞（VSMCs）增殖、凋亡异常在高血压血管重建中起重要作用。我们前期研究发现，高血压血管组织神经肽类物质ACTH表达水平明显升高，但其在高血压血管重建中的力学生物学机制并不清楚。本项目拟应用高血压动物模型，探讨血管组织ACTH及其受体表达与高血压血管重建的关系。之后应用体外张应变加载系统，在细胞水平探讨ACTH及相关转录调控网络在张应变调控ECs和VSMCs增殖、凋亡中的作用机制。最后，分别构建ECs和VSMCs特异性敲除ACTH及其受体的模型小鼠，基于细胞水平研究结果，在体探讨ACTH及相关转录调控因子在高血压血管重建中的分子机制，并探讨其作为高血压药物治疗靶点的可能性。本项目旨在明确血管组织内ACTH及其相关转录调控网络在张应变诱导高血压血管重建中的作用机制，为高血压血管重建病理机制的揭示和疾病临床治疗新靶点的选择提供实验依据。

异常应力（应变）刺激诱导平滑肌细胞（VSMCs）增殖、凋亡异常在高血压血管重建中起重要作用。我们前期研究发现，高血压血管组织神经肽类物质ACTH表达水平明显升高，但其在高血压血管重建中的力学生物学机制并不清楚。本项目拟应用高血压动物模型，探讨血管组织 ACTH 及其受体表达与高血压血管重建的关系。我们的结果显示不同高血压大鼠胸主动脉血管中的ACTH及MC2R高表达。应用FX-5000T Strain Unit对离体培养的VSMCs分别加载5%的生理性张应变和15%的病理性高张应变，显示高张应变促进VSMCs的ACTH及其受体MC2R的mRNA、蛋白水平的增加，并且会诱导VSMCs的增殖。RNAi干扰MC2R会抑制高张应变所引起的VSMCs的增殖。采用不同浓度的ACTH体外静态刺激VCMCs，通过western blotting检测p-ERK和p-Stat3，Brdu检测细胞增殖，ERK拮抗实验及RNAi干扰MC2R验证ACTH促进细胞增殖的具体作用机制。结果显示ACTH通过其受体MC2R，依次激活p-ERK和p-Stat3 727诱导VSMC的增殖。通过自发性高血压大鼠转录因子芯片筛选出差异分子，经IPA分析选择与细胞凋亡相关的转录因Oct-1，通过离体细胞培养实验证明ACTH刺激VSMCs 12 h后LaminB1显著下降，刺激24 h后Oct-1显著下降，目前这一部分的具体机制研究正在进行。本项目旨在揭示力学环境的改变所引起的ACTH增高是否是高血压的致病因素及其作用机制，找出ACTH在血管重建中起调控作用的关键蛋白及相关分子，为高血压的临床预警、诊断与治疗提供力学生物学依据。