基于lncRNA H19调控外排转运蛋白P-gp介导高原缺氧药动学变化及其机制

Pharmacokinetic parameters are the important basis for reasonable clinical medication safety. About drug efflux transporters regulate plateau population pharmacokinetic and mechanism research rarely make the news at home and abroad. Efflux transporters include P-gp, BCRP and MRPs that are the key factors of regulating the pharmacokinetic. It is especially for the bioavailability. We preliminary confirmed plateau hypoxia reduced bioavailability, and rised significantly P-gp and mRNA expression level. Literatures show that the long chain non-coding RNA (lncRNA) regulates P-gp before and after the transcription regulation under micro-environmental hypoxia in tumor. Therefore, we propose an assumption about plateau hypoxia changes affect the pharmacokinetic. It related with H19 regulation of P-gp. This topic will depend on the result of the physiological/pathology and pharmacokinetic parameters change under plateau hypoxia in the early stage as the basis. We will research the expression level of P-gp and mRNA in different tissues and cells under the different hypoxia using the established plateau field laboratory at altitude of 4010 m , plateau environment simulation cabin and hypoxia model. Meantime, we will explain the mechanism that the expressing/silence H19 regulate the expression level of P-gp and mRNA, and transcription factors (HIF1a, NF-κB, etc.). In order to clarify the molecular level based on P - gp regulatory mechanism of pharmacokinetic parameters under the plateau hypoxia. It provides a basis for the rational use of drugs to the plateau.

药动学参数是临床合理安全用药的重要依据。有关药物外排转运蛋白调控高原人群药动学及机制的研究国内外鲜有报道。外排转运蛋白P-gp、BCRP和MRPs是调控药动学特别是生物利用度的关键因素。课题组前期证实高原缺氧降低生物利用度，同时P-gp和mRNA表达水平显著上调；文献表明肿瘤微缺氧下长链非编码RNA(lncRNA)对P-gp转录前后进行调控。因此，我们提出高原缺氧影响药动学变化与 H19对P-gp的调控相关的假设。本课题以前期高原缺氧下生理/病理及药动学参数变化为依据，利用已建成海拔4010m高原实地实验室、高原环境模拟舱和缺氧模型，研究不同缺氧条件下不同组织和细胞中P-gp和mRNA表达水平；同时阐明过表达/沉默H19对细胞中P-gp和mRNA表达水平及转录因子（HIF1a、NF-κB等）的调控机制。以期从分子水平阐明基于P-gp的高原缺氧对药动学参数的调控机制，为高原合理用药提供依据。

药动学参数是临床合理安全用药的重要依据。目前高原缺氧对药物代谢动力学的影响因素研究较少，主要集中在药物代谢酶方面，未见缺氧条件下对药物转运体的研究。药物代谢酶主要存在于肝脏，对于药物的吸收、分布、排泄影响较小，而药物转运体是主动转运药物透过细胞膜进入体内和产生效应的关键因素，如MDR1、BCRP、MRP2、MRP3、OCT、OATP、OAT、PEPT等，其广泛存在于小肠的绒毛上皮细胞、肾小管上皮细胞、肝细胞和胆管上皮细胞，在药物的吸收、分布、代谢和排泄（ADME）各个环节发挥着重要作用，缺氧时药物转运体的变化可能是比药物代谢酶更重要的影响药动学改变的因素。 .本课题依托于已建成海拔4010m的高原实地实验室和细胞缺氧模型，利用RT2 Profiler PCR Arrays技术筛选出缺氧条件下大鼠小肠、肝脏、肾脏组织中存在差异性表达的药物转运体，并采用Real-Time PCR、Western Blot验证各组织中差异显著、作用广泛且存在共性变化的药物转运体的表达。通过考察缺氧条件对药物转运体表达的影响，从而研究高原缺氧条件对大鼠不同组织中药物转运蛋白、相关转录因子、microRNA表达的干预作用；同时通过构建H19基因RNAi慢病毒载体，研究沉默H19对细胞中关键药物转运蛋白P-gp、转录因子（HIF-1a、NF-κB）、核受体（PXR、CAR）的mRNA和蛋白表达的影响，探讨基于lncRNA H19调控外排转运蛋白P-gp介导高原缺氧药动学变化的调控机制。以期从分子水平阐明基于P-gp的高原缺氧环境中对药动学参数的调控机制，为高原合理用药提供依据。