局部RAS异常在孕期炎症刺激致子代大鼠高血压发生中的作用与机制研究

Essential hypertension (EH) of unknown etiology, incidence increased yearly and life-long sympotomatic treatment, may associate with adult individual's strategy in previous studies. We previously demonstrated that offspring hypertension produced in response to prenatal exposure to inflammation. This had been attractted the international recognition and attention, but the system needs to clarify. The traditional view that high circulating renin-angiotensin system (RAS) activity is the main mechanism for hypertension. In previous study we found that the circulating RAS of the offspring rats had not significant changed, but the kidney, local vascular ACE of AngII was significantly increased. This suggestted that the local RAS abnormalities may be an important reason for the rat offspring hypertension. This project will focus on the local RAS exception, system study the change of local RAS in kidney and vascular in hypertensive offspring rats, vascular local variation, and use gene transfection, antisense oligonucleotide technology to regulate its activity change, clearly the local RAS and hypertension of the rat offspring relationship. We will also study the RAS gene promoter DNA methylation and miRNA, such as an in-depth to explore the molecular mechanisms of the local RAS abnormalities. We try to provide new ideas and to deepen the understanding of the pathogenesis of EH and to provide the experimental basis to find a new strategy of the EH intervention.

原发性高血压（EH）病因未明，仍需终生对症治疗，可能与既往研究围绕成年个体开展的策略有关。本室前期研究发现孕期炎症刺激致子代大鼠发生高血压，得到了国际同行的肯定与关注，但机制亟待阐明。传统认为循环肾素-血管紧张素系统（RAS）活性过高是高血压发病主要机制，我们前期研究则发现子代大鼠循环RAS无明显改变, 但肾脏、血管局部ACE、AngII出现显著升高，为此推测局部RAS异常可能是子代大鼠高血压的重要原因。本项目即以局部RAS异常为切入点，系统研究局部RAS各关键分子在子代高血压大鼠肾脏、血管局部的变化规律，并采用基因转染、反义寡核苷酸等技术调控其活性变化，明确局部RAS异常与子代大鼠高血压发生的关系；并从RAS基因启动子DNA甲基化及miRNA等方面深入探讨局部RAS异常的分子机制。旨在为深化对EH发病机制的认识提供新思路,并为寻找EH干预新策略提供实验依据。

在前期发现孕期炎症刺激后子代高血压大鼠血管、肾脏局部RAS异常而循环RAS无改变的基础上，本项目研究局部RAS 各关键分子在子代高血压大鼠肾脏、血管局部的变化规律，明确局部RAS 异常与子代大鼠高血压发生的关系及其异常的分子机制。通过使用ACE抑制剂干预实验发现血管、肾脏局部RAS异常在子代血管、肾脏损伤及高血压发生中具有关键作用。通过NF-κB抑制剂PDTC和抗氧化剂维生素C的干预研究发现血管局部NF-κB信号通路失衡和ACE启动子乙酰化修饰改变可能是导致RAS系统异常的主要机制。进一步研究 PI3K-Akt信号通路过度活化导致IκBa磷酸化而降解从而激活NF-κB通路，同时NF-κB p65对IκBα启动子的结合显著降低，提示NF-κB自身负反馈机制受损可能是导致NF-κB通路失衡的机制。.除了完成预定研究计划外还进一步发现孕期炎症暴露后的子代对盐皮质激素类似物醋酸脱氧皮质酮联合高盐饮水（DOCA-salt）诱导的血压增高及异丙肾上腺素（ISO）诱导的心肌损伤等再刺激因素的敏感性显著增加。进一步研究发现孕期炎症暴露后子代血管、心脏病理性因素再刺激后其相应组织的活性氧（ROS）产生和清除体系失衡而到时ROS水平显著增加，进一步导致血管、心脏组织进行性病理性改变。机制研究发现孕期炎症暴露后子代大鼠血管组织NF-κB信号通路和心脏组织ROS-p38-MAPK信号通路活化。当受到DOCA-salt再次刺激时，血管组织中NF-κB通路持续激活显著抑制PGC-1α表达的快速恢复能力，进而导致氧化应激及血管损伤，促进高血压的发展。而心脏中子代成年后面对心脏损伤危险因素时，通过ROS-p38-MAPK-NADPH氧化酶-ROS正反馈环加重心脏损伤。.在该课题资助下，进行了较广泛的国际、国内学术交流与合作（举办全国会议4次，多人次参加国际、国内学术会议，邀请国外专家来华访教3次）；培养了2名博后、6名博士、硕博连读博士研究生3名，硕士研究生4名）；已发表论文12 篇（其中SCI 收录刊物Immunity、The Journal of Immunology、Scientific Reports、 Plos One 及Mol Cell Biochem发表论文9 篇，在中文核心期刊发表论文3篇。应邀作全国学术大会报告4次，分报告8次。