基于PXR/NF-κB信号通路探究丹参有效成分丹参酮IIA对急性肾损伤的保护及其机制

Acute kidney injury (AKI) is a common disease with a high incidence in clinical conditions. To better contain AKI, anti-inflammation is one of the strategies. Recent researches had found that crosstalk between PXR and NF-κB may influence the progression of inflammation. Our previous data have shown that inflammatory over-reaction aggravates kidney injury by activating NF-κB while inhibiting PXR. Active compounds derived from herbal medicine Salvia miltiorrhiza, are proven to alleviate inflammation during AKI by inhibiting NF-κB and activating PXR, which has re-balanced the crosstalk between PXR/NF-κB signaling pathway. Moreover, by activating PXR, active compounds protect kidneys from injuries by inducing down-stream expressions of metabolic and transporting enzymes, which leads to an increase in the excretion of the renal-harming drugs. On that basis, the study would be designed into three parts: in vivo study depending on ultrasound-microbubble-mediated transgenetic knockdown to the kidneys, in vitro study and molecular docking. we try to study the interactions between PXR and NF-κB, their interactional influences on down-stream molecules, and how Salvia miltiorrhiza alleviates AKI and re-balances the crosstalk signaling by using knock-down expression/overexpression, CoIP, luciferase assay and other techniques. The study is designed to provide the rationales on the crosstalk between PXR/NF-κB signaling pathway in the inflammatory progression of AKI and the underlying molecular mechanisms, which may promote the development of traditional Chinese medicines.

急性肾损伤(AKI)是临床常见病和多发病，控制炎症是治疗AKI的重要策略。近年来发现核受体PXR与炎症调控转录因子NF-κB组成的信号通路可影响炎症进程。我们前期研究结果显示肾损伤后NF-κB信号通路激活、PXR被抑制，过度炎症反应加重肾损伤。中药丹参有效成分丹参酮IIA通过抑制NF-κB、激活PXR，能有效调节该信号通路失衡。同时，丹参酮IIA通过激活PXR诱导下游代谢酶、转运酶表达，加快肾毒性药物代谢，缓解肾损伤。我们拟在此基础上，通过超声微泡转基因体内模型、体外模型、配体-靶标蛋白分子对接三个层面，结合表达抑制或过表达、CoIP、荧光素酶报告基因检测及特异性敲低肾脏PXR等技术观察丹参酮IIA对该信号通路和下游信号的影响，评价其肾保护作用疗效。本项目从多角度阐释丹参酮IIA对PXR/NF-κB信号通路的调控和分子机制，为中药现代化与转化提供科学依据，推动中医药防治急性肾损伤的进展。

本研究为丹参及其生物活性化合物丹参酮IIA（TanIIA）在治疗AKI中的潜在保护作用提供证据，揭示PXR/NF-κB信号在AKI诱导的肾脏炎症中的特异性调控作用以及丹参对AKI的治疗机制。进一步通过体内AKI小鼠模型实验和体外研究用于研究TanIIA在AKI中的肾脏保护作用。网络药理学结果提示核受体家族是丹参治疗AKI的新靶点。体内研究表明，TanIIA通过减少坏死和促进肾小管上皮细胞增殖，改善了肾功能和炎症。肾动脉超声多谱勒显示TanIIA治疗后AKI小鼠肾动脉灌注明显改善。体外研究表明，TanIIA激活PXR同时抑制PXR介导的NF-κB蛋白功能。结果表明，PXR激活对AKI诱导的肾脏炎症起抑制作用。TanIIA通过上调PXR的表达并以PXR依赖的方式抑制NF-κB通路关键蛋白的核转移从而抑制炎症丹参及其有效成分TanIIA可能通过调节核受体PXR来保护肾脏从而缓解AKI。因此，PXR可能是AKI治疗的潜在治疗靶点。