Bai Tao, Cui Yanzhi, Yang Xian, Cui Xinyue, Yan Congmin, Tang Ying, Cao Xiaoming, Dong Chunhui
Pathology Department, First Hospital of Shanxi Medical University, Taiyuan, Shanxi, China.
Medical oncology, Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
Exp Physiol. 2021 Dec;106(12):2531-2541. doi: 10.1113/EP089887. Epub 2021 Nov 9.
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.
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.
本研究的核心问题是什么？miR-302a-3p如何在缺氧复氧诱导的肾小管上皮细胞焦亡中发挥作用？主要发现及其重要性是什么？缺氧复氧处理上调了HK-2细胞中miR-302a-3p的表达，进而抑制了脆性X智力低下蛋白翻译调节因子1（FMR1）的转录，从而促进NLRP3炎性小体的激活并加重HK-2细胞的焦亡。本研究将miR-302a-3p作为分子靶点，为肾衰竭的治疗提供了新的理论依据。
缺氧复氧（H/R）诱导可影响微小RNA（miRNA）表达，进而调控NLR家族含pyrin结构域蛋白3（NLRP3）炎性小体介导的焦亡。本研究探讨了miR-302a-3p在H/R诱导的肾小管上皮细胞（RTEC）焦亡中的作用机制。采用H/R诱导人HK-2肾小管上皮细胞。检测乳酸脱氢酶含量、细胞活性和焦亡情况，以及NLRP3、Gasdermin D-N端（GSDMD-N）、半胱天冬酶-1、白细胞介素（IL）-1β、IL-18、超氧化物歧化酶和丙二醛水平，以验证H/R对HK-2细胞的影响。在用炎性小体抑制剂BAY11-7082处理H/R诱导的HK-2细胞后，评估NLRP3炎性小体的作用。抑制miR-302a-3p表达后，观察焦亡的变化。验证miR-302a-3p与脆性X智力低下蛋白翻译调节因子1（FMR1）之间的结合关系。功能挽救实验验证了FMR1在焦亡调控中的作用。H/R诱导的HK-2细胞出现明显的焦亡损伤，且NLRP3炎性小体被激活。抑制NLRP3炎性小体后，H/R诱导的细胞凋亡受到抑制。H/R处理后，HK-2细胞中的miR-302a-3p增加，miR-302a-3p下调可限制H/R诱导的NLRP3炎性小体介导的焦亡。FMR1是miR-302a-3p的靶点。抑制FMR1可减轻miR-302a-3p抑制剂对H/R诱导的HK-2细胞焦亡的抑制作用。总体而言，抑制miR-302a-3p可减弱其对FMR1的靶向抑制作用，从而抑制NLRP3炎性小体的激活并减少HK-2细胞中半胱天冬酶-依赖性焦亡。
