The First School of Clinical Medicine, Lanzhou University, Lanzhou, China.
The Second School of Clinical Medicine, Lanzhou University, Lanzhou, China.
Biochem Pharmacol. 2022 Mar;197:114839. doi: 10.1016/j.bcp.2021.114839. Epub 2021 Nov 11.
Autophagy is being increasingly recognized as an important regulator of intestinal ischemia-reperfusion(I/R)injury, but its exact role is still debated. Emerging evidence suggests that miR-146a-5p is involved in the initiation and development of I/R injury, but its role in intestinal I/R injury remains unclear. The present study generated an intestinal I/R mouse model and an oxygen glucose deprivation/reoxygenation (OGD/R) Caco-2 cell model and found that autophagy was increased and contributed to the intestinal injury and cell death induced by I/R and OGD/R. In addition, in both I/R and OGD/R models, the miR-146a-5p expression level was decreased and accompanied by an increase in TXNIP expression. By transfecting cells with an miR-146a-5p inhibitor or mimic, we observed that miR-146a-5p inhibits autophagy during OGD/R by targeting TXNIP; this was confirmed by the dual luciferase reporter gene assay. Additionally, through overexpression and knockdown cell lines, we established that TXNIP regulates autophagy during intestinal I/R via the PRKAA/mTOR pathway. The interaction between TXNIP and p-PRKAA was verified by immunofluorescence co-localization and immunoprecipitation assays. Moreover, we confirmed that TXNIP is indispensable for miR-146a-5p-mediated cell protection. Finally, we observed that miR-146a-5p overexpression inhibits autophagy and attenuates intestinal I/R injury via the PRKAA/mTOR pathway by targeting TXNIP in vivo. In conclusion, this study highlights the role of miR-146a-5p in regulating autophagy by targeting TXNIP, suggesting that miR-146a-5p may be a novel drug target for intestinal I/R therapy.
自噬越来越被认为是调节肠道缺血再灌注（I/R）损伤的重要因素，但它的确切作用仍存在争议。新出现的证据表明，miR-146a-5p 参与了 I/R 损伤的发生和发展，但它在肠道 I/R 损伤中的作用尚不清楚。本研究构建了肠道 I/R 小鼠模型和氧葡萄糖剥夺/复氧（OGD/R）Caco-2 细胞模型，发现自噬增加，并有助于 I/R 和 OGD/R 诱导的肠道损伤和细胞死亡。此外，在 I/R 和 OGD/R 模型中，miR-146a-5p 的表达水平降低，同时 TXNIP 表达增加。通过转染细胞用 miR-146a-5p 抑制剂或模拟物，我们观察到 miR-146a-5p 通过靶向 TXNIP 抑制 OGD/R 期间的自噬；这通过双荧光素酶报告基因检测得到证实。此外，通过过表达和敲低细胞系，我们建立了 TXNIP 通过 PRKAA/mTOR 途径调节肠道 I/R 期间的自噬。通过免疫荧光共定位和免疫沉淀检测证实了 TXNIP 与 p-PRKAA 之间的相互作用。此外，我们证实 TXNIP 对于 miR-146a-5p 介导的细胞保护是不可或缺的。最后，我们观察到 miR-146a-5p 过表达通过靶向 TXNIP 抑制自噬并减轻肠道 I/R 损伤，通过体内实验证实了这一点。总之，这项研究强调了 miR-146a-5p 通过靶向 TXNIP 调节自噬的作用，表明 miR-146a-5p 可能是肠道 I/R 治疗的新的药物靶点。
