Department of Clinical Pharmacy, Qinghai University Affiliated Hospital, Xining, China (Y.D.); Research Center for High Altitude Medicine, Qinghai University Medical College, Xining, China (Y.D., X.B., J.Y., G.L., J.Z., L.L.); and State Key Laboratory of Plateau Ecology and Agriculture (X.L.), and Medical College (Y.Z., W.G., Q.W., X.L.), Qinghai University, Xining, China.
Department of Clinical Pharmacy, Qinghai University Affiliated Hospital, Xining, China (Y.D.); Research Center for High Altitude Medicine, Qinghai University Medical College, Xining, China (Y.D., X.B., J.Y., G.L., J.Z., L.L.); and State Key Laboratory of Plateau Ecology and Agriculture (X.L.), and Medical College (Y.Z., W.G., Q.W., X.L.), Qinghai University, Xining, China
Drug Metab Dispos. 2022 Feb;50(2):174-186. doi: 10.1124/dmd.121.000681. Epub 2021 Nov 29.
Hypoxia is the main characteristic of a high-altitude environment, affecting drug metabolism. However, so far, the mechanism of microRNA (miRNA) involved in the regulation of drug metabolism and transporters under high-altitude hypoxia is still unclear. This study aims to investigate the functions and expression levels of multidrug resistance protein 1 (MDR1), multidrug resistance-associated protein 2 (MRP2), breast cancer resistance protein (BCRP), peptide transport 1 (PEPT1), and organic anion-transporting polypeptides 2B1 (OATP2B1) in rats and colon cancer (Caco-2) cells after exposure to high-altitude hypoxia. The protein and mRNA expression of MDR1, MRP2, BCRP, PEPT1, and OATP2B1 were determined by Western blot and qPCR. The functions of MDR1, MRP2, BCRP, PEPT1, and OATP2B1 were evaluated by determining the effective intestinal permeability and absorption rate constants of their specific substrates in rats under high-altitude hypoxia, and uptake and transport studies were performed on Caco-2 cells. To screen the miRNA associated with hypoxia, Caco-2 cells were examined by high throughput sequencing. We observed that the miR-873-5p was significantly decreased under hypoxia and might target MDR1 and pregnane X receptor (PXR). To clarify whether miR-873-5p regulates MDR1 and PXR under hypoxia, Caco-2 cells were transfected with mimics or inhibitors of miR-873-5p and negative control (NC). The function and expression of drug transporters were found to be significantly increased in rats and Caco-2 cells under hypoxia. We found that miR-873-5p regulated MDR1 and PXR expression. Herein, it is shown that miRNA may affect the expression of drug transporter and nuclear receptor under hypoxia. SIGNIFICANCE STATEMENT: This study explores if alterations to the microRNAs (miRNAs), induced by high-altitude hypoxia, can be translated to altered drug transporters. Among miRNAs, which show a significant change in a hypoxic environment, miR-873-5p can act on the multidrug resistance protein 1 (MDR1) gene; however, there are multiple miRNAs that can act on the pregnane X receptor (PXR). This study speculates that the miRNA-PXR-drug transporter axis is important in the physiological disposition of drugs.
缺氧是高原环境的主要特征，会影响药物代谢。然而，到目前为止，微 RNA（miRNA）在高原缺氧环境下调节药物代谢和转运体的机制仍不清楚。本研究旨在探讨多药耐药蛋白 1（MDR1）、多药耐药相关蛋白 2（MRP2）、乳腺癌耐药蛋白（BCRP）、肽转运蛋白 1（PEPT1）和有机阴离子转运多肽 2B1（OATP2B1）在大鼠和结肠癌细胞（Caco-2）暴露于高原缺氧后的功能和表达水平。通过 Western blot 和 qPCR 测定 MDR1、MRP2、BCRP、PEPT1 和 OATP2B1 的蛋白和 mRNA 表达。通过测定大鼠在高原缺氧下其特定底物的有效肠道通透性和吸收速率常数，评估 MDR1、MRP2、BCRP、PEPT1 和 OATP2B1 的功能，并在 Caco-2 细胞上进行摄取和转运研究。为了筛选与缺氧相关的 miRNA，通过高通量测序检查 Caco-2 细胞。我们观察到，miR-873-5p 在缺氧下显著下调，可能靶向 MDR1 和孕烷 X 受体（PXR）。为了阐明 miR-873-5p 是否在缺氧下调 MDR1 和 PXR，Caco-2 细胞转染 miR-873-5p 的模拟物或抑制剂和阴性对照（NC）。结果发现，缺氧下大鼠和 Caco-2 细胞中药物转运体的功能和表达显著增加。我们发现 miR-873-5p 调节 MDR1 和 PXR 的表达。由此可见，miRNA 可能影响缺氧下药物转运体和核受体的表达。意义陈述：本研究探讨了由高原缺氧引起的微 RNA（miRNA）的改变是否可以转化为药物转运体的改变。在缺氧环境中发生显著变化的 miRNA 中，miR-873-5p 可以作用于多药耐药蛋白 1（MDR1）基因；然而，有多个 miRNA 可以作用于孕烷 X 受体（PXR）。本研究推测 miRNA-PXR-药物转运体轴在药物的生理处置中很重要。
