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Deficiency of LncRNA-CIRBIL promotes J-wave syndrome by enhancing transmural heterogeneity of Ito current: LncCIRBIL regulates J-wave syndrome via UPF1
Xuexin Jin, Wenbo Ma, Jinyun Guo, Yueying Qu, Haiyu Gao, Dechun Yin, Desheng Li, Ling Shi, Jialiang Li, Jiudong Ma, Lingmin Zhang, Hongli Shan, Yanjie Lu, Yue Li, Dongmei Gong, Zhenwei Pan
2025, 5(3): 157-169. doi: 10.1515/fzm-2025-0019
Keywords: long noncoding RNA, J-wave syndrome, KCND2, up-frameshift protein1, arrhythmia
  Background  Transmural heterogeneity of the transient outward potassium current (Ito) is a major contributor to J-wave syndrome (JWS). However, the underlying molecular mechanisms remain elusive. The present study aimed to investigate the role of cardiac injury-related bclaf1-interacting lncRNA (lncCIRBIL) in JWS and to delineate the molecular mechanisms.  Methods  Whole-cell patch-clamp techniques were used to record ionic currents and action potentials (APs). Protein and mRNA expression related to Ito current were assessed. RNA immunoprecipitation, RNA Pulldown, mRNA stability, and decapping assays were performed to dissect the underlying mechanisms.  Results  Plasma lncCIRBIL levels were significantly reduced in JWS patients and cold-induced JWS mice. Knockout of lncCIRBIL increased the incidence of J-wave and the susceptibility to ventricular arrhythmia in mice. In lncCIRBIL-deficient mice, the transmural gradient of Kv4.2 expression and Ito current density was markedly enhanced in the right ventricle, but not the left ventricle. In contrast, cardiomyocyte-specific transgenic overexpression of lncCIRBIL produced the opposite effects. In human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), the conserved human homologous fragment of lncCIRBIL (hcf-CIRBIL) suppressed Ito, attenuated the AP notch, and prolonged APD20. Mechanistically, lncCIRBIL directly binds to up-frameshift protein1 (UPF1), promoting KCND2 mRNA decay by enhancing its decapping.  Conclusions  LncCIRBIL modulates the transmural heterogeneity of KCND2 expression by regulating UPF1-mediated mRNA decay. Inhibition of lncCIRBIL exacerbates JWS by enhancing right ventricular Ito heterogeneity, whereas its overexpression exerts protective effects. These findings identify lncCIRBIL as a potential therapeutic target for J-wave syndrome.
Notum protects against myocardial infarction-induced heart dysfunction by alleviating cardiac fibrosis
Tongzhu Jin, Zhen Ye, Ruonan Fang, Yue Li, Wei Su, Qianqian Wang, Tianyu Li, Hongli Shan, Yanjie Lu, Haihai Liang
2024, 4(1): 41-50. doi: 10.2478/fzm-2024-0005
Keywords: cardiac fibrosis, Notum, Wnt/β-catenin, senescence, myocardial infarction
  Background and Objective  Cardiac fibrosis is a pathological reparative process that follows myocardial infarctionand is associated with compromised cardiac systolic and reduced cardiac compliance. The Wnt signaling pathway is closely implicated in organ fibrosis, and Notum, a highly conserved secreted inhibitor, modulates Wnt signaling. The objective of this study was to explore the role and mechanism of Notum in cardiac fibrosis.  Methods  A mouse model of cardiac remodeling was established through left coronary artery ligation surgery, with the addition of Notum injection following myocardial infarction surgery. The protective effect of Notum on myocardial infarction was assessed by evaluating cardiac function, including survival rate, echocardiographic assessment, and cardiac contraction analyses. Inflammatory cell necrosis and infiltration were confirmed through H & E and Masson staining. The expression of fibrosis-related genes and β-catenin pathway markers was detected using Western blot quantificational RT-PCR (qRT-PCR). Additionally, EdU, wound healing, and immunofluorescence staining analyses were performed to detect the effect of Notum's in transforming growth factor beta-1 (TGF-β1) induced myofibroblast transformation.  Results  The administration of Notum treatment resulted in enhanced survival rates, improved cardiac function, and decreased necrosis and infiltration of inflammatory cells in mice subjected to left coronary artery ligation. Furthermore, Notum effectively impeded the senescence of cardiac fibroblasts and hindered their pathological transformation into cardiac fibroblasts. Additionally, it significantly reduced collagen production and attenuated the activation of the Wnt/β-catenin pathway. Our preliminary investigations successfully demonstrated the therapeutic potential of Notum in both fibroblasts in vitro and in a mouse model of myocardial infarction-induced cardiac fibrosis in vivo.  Conclusion  Notum inhibition of the Wnt/β-catenin signaling pathway and cardiac fibroblast senescence ultimately hampers the onset of cardiac fibrosis. Our findings suggest that Notum could represent a new therapeutic strategy for the treatment of cardiac fibrosis.