In vitro and in vivo characteristics of connexin 43-modified human skeletal myoblasts as candidates for prospective stem cell therapy for the failing heart

Abstract

Background: Previously, connexin 43-modified skeletal myoblasts (MbCx) were shown to reduce the pro-arrhythmic effect during the regeneration of heart tissue in an animal model of infarction. To increase the relevance to clinical implementation, in this study, we introduced connexin 43 into human myoblasts using a highly safe non-viral vector and demonstrated that their transplantation had a positive effect on the function of the injured heart.

Methods and results: Myoblasts were efficiently transfected with a pCiNeo-GJA1 plasmid (65.72%). qPCR analysis revealed over 32-fold higher expression of the connexin 43 gene in the MbCx cell population compared to 'native' controls. The susceptibility of the myoblasts to oxidative stress conditions (p<0.001) and the fusion index (p<0.01) were increased in the MbCx cells. Additionally, we observed changes in the MYOG and MYH2 gene expression levels in the GJA1-modified myoblasts. Finally, we observed a significant improvement in the post-infarction echocardiographic parameters after intervention using MbCx cells compared with non-transfected myoblasts (MbWt) and the control (0.9% NaCl), wherein a significant decrease in the left ventricular area change in the short axis (SAX AC%) was observed at the two-month follow-up (p<0.05 and p<0.01, respectively).

Conclusions: We demonstrated the positive effect of connexin 43 overexpression on the biology and function of human skeletal myoblasts in the context of their potential clinical applications. Our preclinical studies using a mouse infarction model indicated the positive effect of MbCx implantation on the function of the injured heart.

Keywords: Cell therapy; Connexin 43; Genetic modification; Human skeletal myoblasts; Post-infarction model.