Liu Min, Chen Xiyun
Department of Intensive Care.
Department of Gynecology, The First Hospital of Changsha, Changsha, Hunan, P.R. China.
Acta Cardiol Sin. 2024 May;40(3):312-321. doi: 10.6515/ACS.202405_40(3).20240127A.
This study aims to investigate the mechanism by which alkB homolog 5 (ALKBH5) regulates polypyrimidine tract-binding protein 1 (PTBP1) to mediate cardiomyocyte pyroptosis in sepsis-induced myocardial injury.
Lipopolysaccharide (LPS)-exposed H9C2 cell and rat models were established to mimic septic myocardial injury both and . The mRNA and protein levels of ALKBH5 and PTBP1 in the LPS-induced cell and septic rat models were detected. CCK-8 and flow cytometry were applied to detect cell viability and pyroptosis. H&E staining was used to observe myocardial tissue damage in rats, and immunohistochemistry to analyze the expression of pyroptosis and inflammation-related proteins in rat tissues.
Elevated expressions of both ALKBH5 and PTBP1 were found in the myocardial tissues of LPS-induced septic rats. ALKBH5 knockdown could restore the cell viability and cell pyroptosis inhibited by LPS, while ALKBH5 promoted PTBP1 mRNA stability by affecting its N6-methyladenosine (m6A) modification. experiments showed that PTBP1 knockdown could largely reverse the antiproliferative and pro-pyroptosis effects of ALKBH5 in LPS-exposed H9C2 cells. ALKBH5 knockdown in in vivo experiments was found to suppress the expressions of pyroptosis biomarkers and attenuate myocardial injury in septic rats.
ALKBH5 promoted mRNA stability and the expression of PTBP1 through m6A modification to induce pyroptosis in cardiomyocytes and ultimately aggravate sepsis-induced myocardial dysfunction.
本研究旨在探究alkB同源物5（ALKBH5）调节多嘧啶序列结合蛋白1（PTBP1）以介导脓毒症诱导的心肌损伤中心肌细胞焦亡的机制。
建立脂多糖（LPS）刺激的H9C2细胞和大鼠模型以模拟脓毒症心肌损伤。检测LPS诱导的细胞和脓毒症大鼠模型中ALKBH5和PTBP1的mRNA和蛋白水平。应用CCK-8和流式细胞术检测细胞活力和焦亡情况。采用苏木精-伊红（H&E）染色观察大鼠心肌组织损伤情况，并用免疫组织化学分析大鼠组织中焦亡和炎症相关蛋白的表达。
在LPS诱导的脓毒症大鼠心肌组织中发现ALKBH5和PTBP1的表达均升高。敲低ALKBH5可恢复LPS抑制的细胞活力和细胞焦亡，而ALKBH5通过影响PTBP1的N6-甲基腺苷（m6A）修饰促进其mRNA稳定性。实验表明，敲低PTBP1可在很大程度上逆转ALKBH5对LPS刺激的H9C2细胞的抗增殖和促焦亡作用。在体内实验中发现，敲低ALKBH5可抑制脓毒症大鼠焦亡生物标志物的表达并减轻心肌损伤。
ALKBH5通过m6A修饰促进mRNA稳定性和PTBP1表达，从而诱导心肌细胞焦亡，最终加重脓毒症诱导的心肌功能障碍。
