Department of Cardiology, The Affiliated Children's Hospital of Xiangya School of Medicine, Central South University (Hunan Children's Hospital), No. 86 Ziyuan Road, Yuhua District, Changsha, Hunan, 410007, People's Republic of China.
Cardiovasc Toxicol. 2024 Dec;24(12):1439-1454. doi: 10.1007/s12012-024-09922-w. Epub 2024 Oct 4.
Viral myocarditis (VMC) is an inflammatory disease of the myocardium caused by cardioviral infection, especially coxsackievirus B3 (CVB3), and is a major contributor to acute heart failure and sudden cardiac death in children and adolescents. LncRNA MALAT1 knockdown reportedly inhibits the differentiation of Th17 cells to attenuate CVB3-induced VMC in mice. Moreover, long non-coding RNAs (lncRNAs) interact with RNA-binding proteins (RBPs) to regulate UPF1-mediated mRNA decay. However, it remains unclear whether MALAT1 can bind to UPF1 to mediate the mRNA decay of its target genes in VMC. Herein, we aimed to explore the effect of lncRNA MALAT1 on UPF1-mediated SIRT6 mRNA decay in VMC using in vivo and in vitro experiments. CVB3-infected BABL/C mice were used as VMC models, and MALAT1 interfering adenovirus was injected to achieve MALAT1 knockdown. The heart function of the VMC mice was assessed using echocardiography. Pathological changes in myocardial tissues were assessed after hematoxylin-eosin staining. Myocardial injury and inflammation were evaluated by measuring creatine kinase isoenzyme B, cardiac troponin T, interleukin (IL)-1β, and IL-18. TUNEL staining was performed to assess apoptosis in myocardial tissues. In vitro experiments were performed using H9c2 cells after transfection and CVB3 infection. The lactic dehydrogenase release, caspase-1 activity, and IL-1β and IL-18 levels in the cellular supernatant were detected. Western blotting was performed to determine the expression of pyroptosis-related proteins (GSDMD-N, NLRP3, ASC, and Cleaved-Caspase-1) and Wnt/β-catenin signal pathway-related proteins (Wnt1, β-catenin, and p-GSK-3β). RNA immunoprecipitation and RNA stability assays assessed the relationship between MALAT1, UPF1, and SIRT6. CVB3-infected mice and H9c2 cells exhibited elevated MALAT1 and reduced SIRT6 expression. MALAT1 knockdown or SIRT6 overexpression suppressed inflammation and pyroptosis and inhibited the activation of the Wnt/β-catenin signal pathway in myocardial tissues and cells. MALAT1 enhanced the enrichment of SIRT6 mRNA by UPF1 and disturbed the stability of SIRT6 mRNA to promote the development of VMC. MALAT1 can bind UPF1 to mediate SIRT6 mRNA decay and activate the Wnt/β-catenin signal pathway in VMC.
病毒性心肌炎（VMC）是由心血管病毒感染引起的心肌炎症性疾病，尤其是柯萨奇病毒 B3（CVB3），是导致儿童和青少年急性心力衰竭和心源性猝死的主要原因。据报道，长链非编码 RNA（lncRNA） MALAT1 的敲低可抑制 Th17 细胞的分化，从而减轻 CVB3 诱导的 VMC 小鼠的心肌炎症。此外，长非编码 RNA（lncRNAs）与 RNA 结合蛋白（RBPs）相互作用，以调节 UPF1 介导的 mRNA 降解。然而，MALAT1 是否可以与 UPF1 结合以介导其靶基因在 VMC 中的 mRNA 降解仍不清楚。在此，我们旨在通过体内和体外实验探讨 lncRNA MALAT1 对 VMC 中 UPF1 介导的 SIRT6 mRNA 降解的影响。用 CVB3 感染的 BABL/C 小鼠作为 VMC 模型，注射 MALAT1 干扰腺病毒以实现 MALAT1 敲低。使用超声心动图评估 VMC 小鼠的心功能。苏木精-伊红染色后评估心肌组织的病理变化。通过测量肌酸激酶同工酶 B、心肌肌钙蛋白 T、白细胞介素（IL）-1β和 IL-18 评估心肌损伤和炎症。通过 TUNEL 染色评估心肌组织中的细胞凋亡。用转染和 CVB3 感染后的 H9c2 细胞进行体外实验。检测细胞上清液中乳酸脱氢酶释放、半胱天冬酶-1 活性以及 IL-1β和 IL-18 水平。通过 Western blot 检测细胞焦亡相关蛋白（GSDMD-N、NLRP3、ASC 和 Cleaved-Caspase-1）和 Wnt/β-catenin 信号通路相关蛋白（Wnt1、β-catenin 和 p-GSK-3β）的表达。RNA 免疫沉淀和 RNA 稳定性分析评估了 MALAT1、UPF1 和 SIRT6 之间的关系。CVB3 感染的小鼠和 H9c2 细胞中 MALAT1 表达升高，SIRT6 表达降低。MALAT1 敲低或 SIRT6 过表达可抑制心肌组织和细胞的炎症和细胞焦亡，并抑制 Wnt/β-catenin 信号通路的激活。MALAT1 通过 UPF1 增强 SIRT6 mRNA 的富集并扰乱 SIRT6 mRNA 的稳定性，从而促进 VMC 的发展。MALAT1 可与 UPF1 结合介导 SIRT6 mRNA 降解，并在 VMC 中激活 Wnt/β-catenin 信号通路。
