Department of Nephrology, The First Affiliated Hospital, Anhui Medical University, Hefei, China.
School of Pharmacy, Anhui Medical University, Hefei, China.
FASEB J. 2019 Mar;33(3):3523-3535. doi: 10.1096/fj.201801711R. Epub 2018 Oct 26.
MLKL is a central mediator for necroptosis. Its knockout significantly relieves acute kidney injury (AKI). However, its upstream regulatory mechanism in AKI has not been fully elucidated. We recently reviewed how microRNAs (miRNAs), a type of well-studied epigenetic regulator, play critical roles in AKI. Here, we evaluated miRNAs that potentially target MLKL and evaluated their function in human tubular epithelial cells in response to toxic and ischemic insults. TargetScan analysis showed that miR-194-5P, miR-338-3P, miR-500a-3P, and miR-577 had MLKL binding sites. Although all 4 miRNAs are reduced in AKI, our data show that only hsa-miR-500a-3P was significantly suppressed in cisplatin-treated human tubular epithelial (HK2) cells. We further found that hsa-miR-500a-3P alleviated cisplatin-induced HK2 cell death, which was confirmed by transmission electron microscopy and flow cytometry. In addition, overexpression of hsa-miR-500a-3P decreased kidney injury molecule-1 mRNA and protein levels. Real-time PCR, ELISA, and immunofluorescence data show that hsa-miR-500a-3P protected against inflammatory response, evidenced by decreased monocyte chemotactic protein-1 and proinflammatory cytokines TNF-α and IL-8. Further, hsa-miR-500a-3P attenuated P65 NF-κB phosphorylation and promoter activity. Mechanistically, luciferase reporter assay showed that hsa-miR-500a-3P bound the 3'UTR of MLKL, thereby suppressing phosphorylation and membrane translocation of MLKL. In agreement with these findings, we identified that overexpression of hsa-miR-500a-3P attenuated cell injury and the inflammatory response in response to sodium azide treatment in an in vitro model. Results show that circulating exosomes from patients with AKI down-regulated miR-500a-3P, which suppressed cell injury and inflammation in HK2 cells. hsa-miR-500a-3P alleviated toxic and ischemic insults that were triggered by cell necroptosis and the inflammatory response in human HK2 cells by targeting MLKL. This may serve as a novel therapeutic target for treatment of AKI.-Jiang, L., Liu, X.-Q., Ma, Q., Yang, Q., Gao, L., Li, H.-D., Wang, J.-N., Wei, B., Wen, J., Li, J., Wu, Y.-G., Meng, X.-M. hsa-miR-500a-3P alleviates kidney injury by targeting MLKL-mediated necroptosis in renal epithelial cells.
MLKL 是细胞坏死的核心介质。其敲除可显著缓解急性肾损伤(AKI)。然而,其在 AKI 中的上游调控机制尚未完全阐明。我们最近回顾了 microRNAs(miRNAs),作为一种研究充分的表观遗传调节剂,在 AKI 中发挥关键作用。在这里,我们评估了可能靶向 MLKL 的 miRNAs,并评估了它们在应对毒性和缺血性损伤时对人肾小管上皮细胞的功能。TargetScan 分析显示,miR-194-5P、miR-338-3P、miR-500a-3P 和 miR-577 具有 MLKL 结合位点。尽管这 4 种 miRNA 在 AKI 中均减少,但我们的数据表明,只有 miR-500a-3P 在顺铂处理的人肾小管上皮(HK2)细胞中显著受抑制。我们进一步发现,miR-500a-3P 减轻了顺铂诱导的 HK2 细胞死亡,这通过透射电子显微镜和流式细胞术得到了证实。此外,miR-500a-3P 的过表达降低了肾损伤分子 1 mRNA 和蛋白水平。实时 PCR、ELISA 和免疫荧光数据表明,miR-500a-3P 可通过降低单核细胞趋化蛋白 1 和促炎细胞因子 TNF-α和 IL-8 来保护对抗炎症反应。此外,miR-500a-3P 减弱了 P65 NF-κB 的磷酸化和启动子活性。机制上,荧光素酶报告基因检测显示,miR-500a-3P 结合 MLKL 的 3'UTR,从而抑制 MLKL 的磷酸化和膜易位。与这些发现一致,我们发现,miR-500a-3P 的过表达减轻了体外模型中对叠氮钠处理的细胞损伤和炎症反应。结果表明,AKI 患者的循环外泌体下调 miR-500a-3P,从而减轻 HK2 细胞的细胞损伤和炎症。miR-500a-3P 通过靶向 MLKL 减轻由细胞坏死和人 HK2 细胞炎症反应引起的毒性和缺血性损伤。这可能成为治疗 AKI 的新的治疗靶点。