Notum protects against myocardial infarction-induced heart dysfunction by alleviating cardiac fibrosis

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 andβ-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.