Department of Geriatric Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, Guangdong, China.
Chin J Physiol. 2023 Sep-Oct;66(5):335-344. doi: 10.4103/cjop.CJOP-D-23-00029.
Acute lung injury is a severe clinical condition constituting a major cause of mortality in intensive care units. This study aimed to investigate the role of klotho in alleviating lipopolysaccharide (LPS)-induced acute lung injury. LPS-induced acute lung injury was used to simulate the acute lung injury caused by severe pneumonia in vitro. The viability and apoptosis of A549 cells were detected by cell counting kit-8 assay and flow cytometry. The inflammatory response, oxidative stress, and mitochondrial function in A549 cells were analyzed by commercial assay kits and 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-benzimidazolyl carbocyanine iodide (JC-1) staining. The expression of apoptosis-related proteins, Sirtuin 1 (SIRT1)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway-related proteins, and NOD-like receptor family pyrin domain containing 3 (NLRP3) expression in A549 cells was detected by western blot. The mtDNA synthase level in A549 cells was analyzed by reverse transcription-quantitative polymerase chain reaction. The results showed that, klotho had no cytotoxic effect on A549 cells. The viability and mitochondrial function were inhibited and apoptosis, inflammatory response, and oxidative stress were aggravated in LPS-induced A549 cells, which were all reversed by klotho. Klotho activated the SIRT1/Nrf2 signaling pathway to inhibit the LPS-induced NLRP3 inflammasome activation in A549 cells. However, EX527, a SIRT1 inhibitor, attenuated the klotho effect to suppress viability and mitochondrial function and promoted apoptosis, inflammatory response, and oxidative stress of A549 cells. In conclusion, klotho inhibited the activation of NLRP3 inflammasome to alleviate LPS-induced inflammatory injury of A549 cells and restore mitochondrial function through activating the SIRT1/Nrf2 signaling pathway.
急性肺损伤是一种严重的临床病症，构成了重症监护病房患者死亡的主要原因。本研究旨在探讨 Klotho 在缓解脂多糖（LPS）诱导的急性肺损伤中的作用。采用 LPS 诱导的急性肺损伤体外模拟严重肺炎引起的急性肺损伤。通过细胞计数试剂盒-8 检测和流式细胞术检测 A549 细胞的活力和凋亡。通过商业检测试剂盒和 5,5',6,6'-四氯-1,1',3,3'-四乙基苯并咪唑基碳氰化物碘化物（JC-1）染色分析 A549 细胞的炎症反应、氧化应激和线粒体功能。通过 Western blot 检测 A549 细胞中凋亡相关蛋白、Sirtuin 1（SIRT1）/核因子红细胞 2 相关因子 2（Nrf2）信号通路相关蛋白和 NOD 样受体家族含吡咯域蛋白 3（NLRP3）的表达。通过逆转录定量聚合酶链反应分析 A549 细胞中线粒体 DNA 合酶水平。结果表明，Klotho 对 A549 细胞无细胞毒性作用。LPS 诱导的 A549 细胞活力和线粒体功能受到抑制，凋亡、炎症反应和氧化应激加剧，而 Klotho 则逆转了这一趋势。Klotho 激活了 SIRT1/Nrf2 信号通路，抑制了 LPS 诱导的 A549 细胞 NLRP3 炎性小体的激活。然而，SIRT1 抑制剂 EX527 减弱了 Klotho 抑制 A549 细胞活力和线粒体功能并促进凋亡、炎症反应和氧化应激的作用。综上所述，Klotho 通过激活 SIRT1/Nrf2 信号通路抑制 NLRP3 炎性小体的激活，减轻 LPS 诱导的 A549 细胞炎症损伤，恢复线粒体功能。
