MicroRNA miR-301a is a novel cardiac regulator of Cofilin-2

Abstract

Calsarcin-1 deficient mice develop dilated cardiomyopathy (DCM) phenotype in pure C57BL/6 genetic background (Cs1-ko) despite severe contractile dysfunction and robust activation of fetal gene program. Here we performed a microRNA microarray to identify the molecular causes of this cardiac phenotype that revealed the dysregulation of several microRNAs including miR-301a, which was highly downregulated in Cs1-ko mice compared to the wild-type littermates. Cofilin-2 (Cfl2) was identified as one of the potential targets of miR-301a using prediction databases, which we validated by luciferase assay and mutation of predicted binding sites. Furthermore, expression of miR-301a contrastingly regulated Cfl2 expression levels in neonatal rat ventricular cardiomyocytes (NRVCM). Along these lines, Cfl2 was significantly upregulated in Cs1-ko mice, indicating the physiological association between miR-301a and Cfl2 in vivo. Mechanistically, we found that Cfl2 activated serum response factor response element (SRF-RE) driven luciferase activity in neonatal rat cardiomyocytes and in C2C12 cells. Similarly, knockdown of miR301a activated, whereas, its overexpression inhibited the SRF-RE driven luciferase activity, further strengthening physiological interaction between miR-301a and Cfl2. Interestingly, the expression of SRF and its target genes was strikingly increased in Cs1-ko suggesting a possible in vivo correlation between expression levels of Cfl2/miR-301a and SRF activation, which needs to be independently validated. In summary, our data demonstrates that miR-301a regulates Cofilin-2 in vitro in NRVCM, and in vivo in Cs1-ko mice. Our findings provide an additional and important layer of Cfl2 regulation, which we believe has an extended role in cardiac signal transduction and dilated cardiomyopathy presumably due to the reported involvement of Cfl2 in these mechanisms.

Zebrafish VCAP1X2 regulates cardiac contractility and proliferation of cardiomyocytes and epicardial cells

“…Expression of genes encoding sarcomere proteins, such as myosin heavy chain 6 ( myh6) , myosin heavy chain 7 ( myh7 ), ventricle myosin heavy chain like ( vmhcl ), troponin T ( tnnt2a ), myopalladin ( mypn ) and four and a half LIM domains 2a ( fhl2a ), was significantly downregulated in VCAP1X2 mutants compared to WT. Expression levels of two natriuretic peptides ( nppa , nppb ) were substantially increased in VCAP1X2 mutant heart, similar to other DCM animal models 25 . We then compared expression levels of the sarcomere modulator, smyd1b 6 , stress response regulators [integrin subunit beta1 binding protein 2 ( itgb1bp2 ) 26 and ankyrin repeat domain 1 ( ankrd1 ) 27 ] and chaperones ( hsp90aa1.1 , unc45b , αB-crystallin/ cryabb ) 28 , 29 in VCAP1X2 mutant and WT hearts (Fig.…”

Actin-associated proteins and cardiomyopathy—the ‘unknown’ beyond troponin and tropomyosin

“…However, when cofilin-2 expression is knocked down in cultured cardiomyocytes, a marked elongation of thin filaments is observed and proper I-band striations are lost (Kremneva et al 2014 ). In a mouse model for DCM, the calsarcin knockout mouse, cofilin-2 expression was increased due to a decrease in miRNA miR-301a expression and was subsequently shown to be a direct target for this miRNA (Rangrez et al 2017 ). Cofilin-2 function is regulated by phosphorylation, and fasudil, an inhibitor of ROCK (Rho kinase), which has a protective effect against cardiac dysfunction, prevents its phosphorylation and promotes the organisation of actin filaments (Lai et al 2017 ).…”

MiR-301a promotes embryonic stem cell differentiation to cardiomyocytes

“…The enrichment of miR-301a in active cardiomyocytes was originally determined from our miRNA screening study in the hearts of neonatal rodents[26], which was recently confirmed by Rangrez et al[24], who detected much higher expression of miR-301a in isolated cardiomyocytes than in fibroblasts. That study also found that miR-301a negatively regulates SRF signaling through inhibiting the expression of the target gene Cofilin-2 in cardiomyocytes, suggesting the therapeutic potential of miR-301a in the treatment of cardiac disorders caused by the deregulation of Cofilin-2[24]. Here, we first showed that miR-301a has a high level in the hearts of late-stage embryos, while it is low in undifferentiated ES cells and cardiomyocytes in early-stage embryos.…”

“…In the current study, we identified miR-301a as a highly enriched miRNA in embryonic and neonatal cardiomyocytes. Although overexpression of miR-301a is frequently observed in diverse tumor types, promoting cell proliferation, invasion, and metastasis of cancer cells[21-23], the functional properties of miR-301a in the heart remain unclear, except one recent report indicating that miR-301a is a novel cardiac regulator of Cofilin-2 in cardiomyocytes[24]. In contrast to its function in tumors, miR-301a may have tissue-specific functions in the heart.…”