Differential sex-dependent role of lncRNAs in cardiomyopathy

Abstract

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Education and Science Cardiovascular diseases are one of the most prevalent causes of mortality and morbidity worldwide. Structural diseases such as dilated and hypertrophic cardiomyopathy significantly contributed to it. In recent years, several studies have pinpointed the importance of non-coding genome in the pathogenesis of cardiomyopathy. We have previously reported the role of distinct lncRNAs in atrial fibrillation. We now explored the plausible role of these lncRNAs in cardiomyopathy by analyzing their expression in two different mouse mutant models of lamin (LMNA) - LMNAR249W and αMHCCreLMNAFF, a cardiac hypertrophic MyBPC3 mutant model as well as in experimental myocardial infarction mice. Importantly, both LMNA mutant models developed a dilated cardiomyopathy, a condition distinctly observed in males but not in females. Our data demonstrated that Walras, Gm26533, Wallrd, Walaa and Walrad are downregulated in females, but not males. Furthermore, differential deregulation is also observed in MyBPC3 mutant model but not in myocardial infarction. In vitro analyses demonstrated an estrogen-dependent regulation. In addition, expression analyses in distinct cardiovascular cell lines revealed enriched myocardial expression of Walras and Gm26533 while Wallrd and Walaa are preferentially expressed in endocardial cells. These data were further validated by in situ hybridization in embryonic cardiac tissues. Walras overexpression resulted in enhanced expression of two key factors of UPR signaling pathway, i.e. Atf6 and Ire1, while Walras inhibition downregulated them. Upregulation of both UPR factors in Walrasgain-of-function assays is accompanied by increased cardiomyocyte apoptosis. In contrast, Walras inhibition resulted in increased Bcl2 expression and therefore increased cell viability. Mechanistically, Walras directly interacts with calumenin protein, a known protective factor against UPR-associated apoptosis, as demonstrated by pulldown assays. In sum, we demonstrated sex-dependent regulation of distinct lncRNAs in different cardiomyopathic mouse models and at least one of them, i.e. Walras contributes to UPR-associated apoptosis regulation, providing a causative link to the development of distinct cardiomyopathies.