Yuan Ludong, Li Jing, Yin Leijing, Lin Xiaofang, Ni Dan, Deng Chuanhuan, Liang Pengfei, Jiang Bimei
Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan 410008, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan 410078, China.
Department of Burns and Plastic Surgery, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.
Int J Biochem Cell Biol. 2025 Feb;179:106714. doi: 10.1016/j.biocel.2024.106714. Epub 2024 Dec 2.
We revealed for the first time that the expression of 158 tRNA-derived small RNAs (tsRNAs) was altered in septic cardiomyopathy (SCM) by microarray analysis, and we selected 5'tiRNA-33-CysACA-1, which was the most significantly up-regulated, as a representative to explore the roles and mechanisms of tsRNAs in SCM.
We constructed a sepsis model by cecum ligation and puncture (CLP) in mice and detected the expression of 5'tiRNA-33-CysACA-1 using quantitative real-time PCR (qRT-PCR). The supernatant generated after LPS stimulation of macrophages was used as the conditional medium (CM) to stimulate H9C2 and established the injured cell model. CCK-8 and LDH release assays were used to detect cell viability and cell death. Mitochondrial membrane potential (MMP), ATP production, ROS production, and Mitotracker Red mitochondrial morphology were assayed to assess mitochondrial function. Expression of mRNA for molecules related to the mitochondrial quality control system was verified by qRT-PCR. The mechanism by which 5'tiRNA-33-CysACA-1 regulates peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) expression was examined by western blot, mRNA stability analysis, and rescue experiments.
Expression of 5'tiRNA-33-CysACA-1 was elevated in cardiac tissue and H9C2 cells during septic myocardial injury. Stimulation of the CM resulted in cardiomyocyte injury and impaired mitochondrial function. Transfection of 5'tiRNA-33-CysACA-1 mimic in CM further downregulated PGC-1α expression, inhibited mitochondrial biogenesis thereby impairing mitochondrial function and leading to decreased cardiomyocyte activity and increased cell death. In contrast, transfection of the inhibitor ameliorated the above biological processes. In addition, mRNA stability assay and bioinformatics analysis showed that 5'tiRNA-33-CysACA-1 led to a decrease in the stability of PGC-1α mRNA, which in turn downregulated the expression of PGC-1α and promoted the development of SCM.
5'tiRNA-33-CysACA-1 expression is upregulated in SCM and inhibits mitochondrial biogenesis by targeting PGC-1α and decreasing the stability of PGC-1α mRNA, leading to mitochondrial dysfunction and promoting the development of SCM.
我们通过微阵列分析首次揭示了158种tRNA衍生的小RNA（tsRNAs）在脓毒症性心肌病（SCM）中的表达发生了改变，我们选择上调最显著的5'tiRNA-33-CysACA-1作为代表，以探讨tsRNAs在SCM中的作用和机制。
我们通过小鼠盲肠结扎和穿刺（CLP）构建脓毒症模型，并使用定量实时PCR（qRT-PCR）检测5'tiRNA-33-CysACA-1的表达。巨噬细胞经脂多糖（LPS）刺激后产生的上清液用作条件培养基（CM）来刺激H9C2细胞，从而建立损伤细胞模型。采用CCK-8和乳酸脱氢酶（LDH）释放试验检测细胞活力和细胞死亡情况。检测线粒体膜电位（MMP）、ATP生成、活性氧（ROS）生成以及用Mitotracker Red检测线粒体形态，以评估线粒体功能。通过qRT-PCR验证线粒体质量控制系统相关分子的mRNA表达。通过蛋白质免疫印迹法、mRNA稳定性分析和拯救实验研究5'tiRNA-33-CysACA-1调节过氧化物酶体增殖物激活受体γ共激活因子-1α（PGC-1α）表达的机制。
在脓毒症性心肌损伤期间，心脏组织和H9C2细胞中5'tiRNA-33-CysACA-1的表达升高。CM刺激导致心肌细胞损伤和线粒体功能受损。在CM中转入5'tiRNA-33-CysACA-1模拟物进一步下调PGC-1α表达，抑制线粒体生物合成，从而损害线粒体功能，导致心肌细胞活性降低和细胞死亡增加。相反，转入抑制剂可改善上述生物学过程。此外，mRNA稳定性分析和生物信息学分析表明，5'tiRNA-33-CysACA-1导致PGC-1α mRNA稳定性降低，进而下调PGC-1α表达并促进SCM的发展。
5'tiRNA-33-CysACA-1在SCM中表达上调，并通过靶向PGC-1α和降低PGC-1α mRNA稳定性来抑制线粒体生物合成，导致线粒体功能障碍并促进SCM的发展。
