Inhibition of MicroRNA-9-5p Protects Against Cardiac Remodeling Following Myocardial Infarction in Mice

Abstract

Follistatin-like 1 (Fstl1) protects cardiomyocytes from a broad spectrum of pathologic injuries including myocardial infarction (MI). It is worthy of note that although cardiac Fstl1 is elevated in post-MI microenvironment, its cardioprotective role is still restricted to a limited extent considering the frequency and severity of adverse cardiac remodeling following MI. We therefore propose that intrinsic Fstl1-suppressing microRNA (miRNA) may exist in the heart and its neutralization may further facilitate post-MI recovery. Here, miR-9-5p is predicted as one of the potential Fstl1-targeting miRNAs whose expression is decreased in ischemic myocardium and reversely correlated with Fstl1. Luciferase activity assay further validated Fstl1 as a direct target of miR-9-5p. In addition, forced expression of miR-9-5p in H9c2 cells is concurrent with diminished expression of Fstl1 and vice versa. Importantly, transfection of miR-9-5p mimics in hypoxic H9c2 cells exacerbates cardiac cell death, lactate dehydrogenase release, reactive oxygen species accumulation, and malonyldialdehyde concentration. More importantly, in vivo silencing of miR-9-5p by a specific antagomir in a murine acute MI model effectively preserves post-MI heart function with attenuated fibrosis and inflammatory response. Further studies demonstrated that antagomir treatment stabilizes Fstl1 expression as well as blocks cardiac cell death and reactive oxygen species generation in both ischemia-challenged hearts and hypoxia-treated cardiomyoblasts. Finally, cytoprotection against hypoxic challenge by miR-9-5p inhibitor is partially reversed by knockdown of Fstl1, indicating a novel role of miR-9-5p/Fstl1 axis in survival defense against hypoxic challenge. In summary, these findings identified miR-9-5p as a mediator of hypoxic injury in cardiomyoblasts and miR-9-5p suppression prevents cardiac remodeling after acute MI, providing a potential strategy for early treatment against MI.

miR-200c-3p Regulates Epitelial-to-Mesenchymal Transition in Epicardial Mesothelial Cells by Targeting Epicardial Follistatin-Related Protein 1

“…Once addressed the induction of FSTL1 in TGF β1-mediated EMT of EMCs, we investigated whether FSTL1 could be a direct target of miR-200c. Several studies already demonstrated the presence of multiple miRNA-binding sites in the 3′UTR of FSTL1 mRNA and their role in the inhibition of FSTL1 expression [ 31 , 32 , 33 , 34 ].…”

Construction and Analysis of a ceRNA Network in Cardiac Fibroblast During Fibrosis Based on in vivo and in vitro Data

“…miR-9-5p may exert a cell-specific effect during cardiac fibrosis. Inhibition of miR-9-5p in cardiomyocytes reverses cardiac remodeling (Xiao et al, 2019) while it suppresses CF activation (Fierro-Fernandez et al, 2015;Wang et al, 2016). Its effect on CF seems plausible because it targets TGFBI, which is expressed predominately in fibroblasts (Uhlen et al, 2015).…”

Integrated Analysis of Hub Genes and miRNAs in Dilated Cardiomyopathy

“…Similarly, the expression level of miR-9 was upregulated in H9C2 cells subject to hypoxia, and the hypoxia-induced cardiomyocyte apoptosis was inhabited by the miR-9 knockdown procedure [ 28 ]. The expression level of miR-9-5p decreased in the ischemic myocardium [ 29 ]. Jin et al established the rodent myocardial infarction model and proved that compared with the sham group, the rats in the miR-9 group had substantially decreased type I and type III collagen, suggesting that miR-9 can alleviate the myocardium fibrosis process in cardiomyopathy [ 30 ].…”