miR-302a-3p targets FMR1 to regulate pyroptosis of renal tubular epithelial cells induced by hypoxia-reoxygenation injury

Abstract

New findings: What is the central question of this study? How does miR-302a-3p play a role in hypoxia-reoxygenation-induced pyroptosis of renal tubular epithelial cells? What is the main finding and its importance? Hypoxia-reoxygenation treatment upregulated the expression of miR-302a-3p in HK-2 cells, and then inhibited the transcription of FMRP translational regulator 1 (FMR1), so as to promote the activation of the NLRP3 inflammasome and aggravate the pyroptosis of HK-2 cells. miR-302a-3p was used as a molecular target in this study, which provides a new theoretical basis for the treatment of renal failure.

Abstract: Hypoxia-reoxygenation (H/R) induction can affect miRNA expression and then control NLR family pyrin domain containing 3 (NLRP3) inflammasome-mediated pyroptosis. This study investigated the mechanism of miR-302a-3p in H/R-induced renal tubular epithelial cell (RTEC) pyroptosis. Human HK-2 RTECs were induced by H/R. Lactate dehydrogenase content, cell activity and pyroptosis, and levels of NLRP3, GSDMD-N, caspase-1, interleukin (IL)-1β, IL-18, superoxide dismutase, and malondialdehyde were detected to verify the effect of H/R on HK-2 cells. The NLRP3 inflammasome action was evaluated after H/R-induced HK-2 cells were treated with BAY11-7082, an inflammasome inhibitor. After inhibiting miR-302a-3p expression, the changes of pyroptosis were observed. The binding relation between miR-302a-3p and FMRP translational regulator 1 (FMR1) was verified. A function-rescue experiment verified the role of FMR1 in the regulation of pyroptosis. H/R-induced HK-2 cells showed significant pyroptosis injury, and the NLRP3 inflammasome was activated. After inhibiting the NLRP3 inflammasome, H/R-induced apoptosis was inhibited. After H/R treatment, miR-302a-3p in HK-2 cells was increased, and miR-302a-3p downregulation limited H/R-induced NLRP3 inflammasome-mediated pyroptosis. FMR1 is the target of miR-302a-3p. Inhibition of FMR1 alleviated the inhibition of H/R-induced HK-2 cell pyroptosis by miR-302a-3p inhibitor. Collectively, inhibiting miR-302a-3p can weaken its targeted inhibition on FMR1, thereby inhibiting the activation of NLRP3 inflammasomes and reducing caspase-1-dependent pyroptosis in HK-2 cells.

Keywords: FMR1; NLRP3/caspase-1; hypoxia-reoxygenation; miR-302a-3p; pyroptosis; renal tubular epithelial cells.