下丘脑室旁核活性肽salusinβ通过TLR4/MAPK/NF-κB信号通路调控高血压的研究

The hypothalamic paraventricular nucleus (PVN) is an important integrative site in control of cardiovascular activity, which is involved in the excessive sympathetic nervous activity of hypertension. Salusin β, a multifunctional bioactive peptide, plays a key role in the development and progression of cardiovascular diseases. Our previous study demonstrated that immunoneutralize salusin β in the PVN significantly attenuated hypertension and renal sympathetic nerve activity, and reduced inflammatory response in the PVN of spontaneously hypertensive rats. However, it is known the underlying molecular mechanisms are far from understanding. In this study, we aim to investigate the role of salusin β in the hypothalamic paraventricular nucleus and to evaluate whether central salusin β blockade has any protective role in hypothalamic inflammation, sympathetic nervous activity and hypertension by short hairpin RNA, co-immunoprecipitation and laser scanning confocal microscope techniques in spontaneously hypertensive rats. We also determined whether TLR4/MAPK/NF-κB signaling pathway in the PVN is involved in the effects of salusin β. The inhibitors of TLR4, MAPK or NF-κB will be applied to in vitro to demonstrate whether TLR4/MAPK/NF-κB signaling pathway in the PVN mediates the effects of salusin β. This study will illuminate the relationship between salusin β in the PVN and the pathogenesis of hypertension, and provide new strategy and novel targets for the prevention and treatment of hypertension.

下丘脑室旁核(PVN)是调控心血管活动的重要中枢部位，与高血压交感神经活动增强密切相关。国内外文献和我们前期研究提示活性肽salusin β可能参与高血压等多种心血管疾病的发生发展。阻断高血压大鼠PVN中salusin β可减弱PVN的炎性反应，降低交感神经活动和血压，但其分子机制不明。本项目以自发性高血压大鼠为研究对象，从整体-细胞-分子水平入手，采用经PVN慢性给药、shRNA和免疫共沉淀等技术，开展以下三方面研究：1）高血压时salusin β对室旁核炎性反应、交感神经活动和血压的影响；2）在体实验验证高血压时salusin β是否室旁核通过TLR4/MAPK/NF-κB信号通路影响交感神经活动和血压的变化；3）细胞水平明确TLR4/MAPK/NF-κB信号通路是否介导salusin β的效应。最终阐明PVN中salusin β与高血压发病机制的关系，为防治高血压提供新思路和新靶点。

下丘脑室旁核(PVN)是调控心血管活动的重要中枢部位，与高血压交感神经活动增强密切相关。活性肽salusin β是一种具有多种生物学效应的活性肽，可能参与高血压等多种心血管疾病的发生发展。本项目以自发性高血压大鼠和下丘脑神经元为研究对象，探讨自发性高血压大鼠PVN中活性肽salusin β对血压和交感神经活动的影响以及TLR4/MAPK/NF-κB信号通路是否介导这一过程。研究结果发现高血压时PVN中活性肽salusin β表达明显升高，同时检测到PVN中的salusin β主要在神经元中表达。PVN给予慢病毒携带的shRNA敲低室旁核salusin β(免疫荧光观察慢病毒表达效率和位置，Western blotting检测salusin β蛋白的表达)，发现高血压大鼠平均动脉血压降低，交感神经活动减弱，PVN中活性氧簇产生明显减少，抗氧化能力提高，炎症细胞因子表达下降；与此同时，我们还发现PVN中TLR4表达降低，MAPK和NF-κB信号通路关键蛋白表达降低。以上结果提示高血压时升高的活性肽salusin β可能通过激活PVN中TLR4/MAPK/NF-κB信号通路，进而增加炎症反应和活性氧簇的产生，最终增加交感神经活性和血压。通过体内体外实验，分别给予TLR4、MAPK 或NF-κB抑制剂后给予salusin β，发现活性肽salusin β产生的效应得到抑制。基于上述结果，我们推测室旁核TLR4/MAPK/NF-κB信号通路可能介导活性肽salusin β产生的效应。本项目研究结果将为高血压时交感神经兴奋的机制补充新的观点，可望为高血压的治疗提供潜在的干预靶点。