Department of Emergency, Affiliated Hospital of Nantong University, Nantong, China.
Yonsei Med J. 2021 Mar;62(3):262-273. doi: 10.3349/ymj.2021.62.3.262.
This study aimed to explore the role of the long non-coding RNA (lncRNA) RNA component of mitochondrial RNAase P (RMRP) in sepsis-induced acute kidney injury (AKI).
Venous blood was collected from septic patients and healthy people. C57BL/6 mice who underwent cecal ligation and puncture (CLP) were used as in vivo models of septic AKI. Lipopolysaccharide (LPS)-induced HK-2 cells were employed as in vitro models of AKI. Flow cytometry analysis was conducted to detect cell apoptosis. Enzyme-linked immunosorbent assay and Western blot assays were used to detect levels of pro-inflammatory cytokines.
RMRP was upregulated in sera from patients with AKI and in LPS-induced cells. Knockdown of RMRP inhibited cell apoptosis and reduced production of inflammatory factors in LPS-induced cells, as well as alleviated AKI in CLP mice. RMRP facilitated inflammation by activating NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome. We found that microRNA 206 (miR-206) binds with and is negatively regulated by RMRP: miR-206 directly targets the 3' untranslated region of DEAD-box helicase 5 (DDX5) and negatively regulates DDX5 expression. By binding with miR-206, RMRP upregulated DDX5 expression. Rescue assays revealed that overexpression of DDX5 counteracted the effect of RMRP inhibition on cell apoptosis and inflammatory response in LPS-induced cells.
The lncRNA RMRP contributes to sepsis-induced AKI through upregulation of DDX5 in a miR-206 dependent manner and through activation of NLRP3 inflammasome. This novel discovery may provide a potential strategy for treating AKI.
本研究旨在探讨线粒体 RNA 酶 P（RMRP）的长非编码 RNA（lncRNA）在脓毒症诱导的急性肾损伤（AKI）中的作用。
采集脓毒症患者和健康人的静脉血。C57BL/6 小鼠接受盲肠结扎穿孔（CLP）作为脓毒症 AKI 的体内模型。脂多糖（LPS）诱导的 HK-2 细胞用作 AKI 的体外模型。采用流式细胞术分析检测细胞凋亡。酶联免疫吸附试验和 Western blot 检测炎症因子水平。
RMRP 在 AKI 患者血清和 LPS 诱导的细胞中上调。敲低 RMRP 抑制 LPS 诱导的细胞凋亡和炎症因子的产生，并减轻 CLP 小鼠的 AKI。RMRP 通过激活 NACHT、LRR 和 PYD 结构域包含蛋白 3（NLRP3）炎症小体促进炎症。我们发现 microRNA 206（miR-206）与 RMRP 结合并受其负调控：miR-206 直接靶向 DEAD-box 解旋酶 5（DDX5）的 3'非翻译区并负调控 DDX5 的表达。通过与 miR-206 结合，RMRP 上调 DDX5 的表达。挽救实验表明，DDX5 的过表达抵消了 RMRP 抑制对 LPS 诱导的细胞凋亡和炎症反应的影响。
lncRNA RMRP 通过 miR-206 依赖的方式上调 DDX5 并通过激活 NLRP3 炎症小体促进脓毒症诱导的 AKI。这一发现为治疗 AKI 提供了一种潜在的策略。
