CFTR deficiency causes cardiac dysplasia during zebrafish embryogenesis and is associated with dilated cardiomyopathy
Abstract Background: Mutations in the CFTR gene cause cystic fibrosis (CF) with myocardial dysfunction. However, it remains unknown whether CF-related heart disease is a secondary effect of pulmonary disease, or an intrinsic primary defect in the CF heart. Results: Here, we used a zebrafish model, which lacks lung tissue, to investigate the role of CFTR in cardiogenesis during embryonic development. Our findings demonstrate that a loss of CFTR impairs cardiac development from the cardiac progenitor stage of heart development, resulting in cardiac looping defects, a dilated atrium, pericardial edema, and a decrease in heart rate. Furthermore, we found that cardiac development is perturbed in wild type embryos treated with a gating specific Cftr channel inhibitor, CFTRinh-172, at the blastula stage of development, but not with treatment at later stages. Gene expression analysis of blastulas indicated that transcript levels, including mRNAs associated with cardiovascular diseases, were significantly altered in embryos derived from cftr mutants relative to controls. To evaluate the role of CFTR in human heart failure, we performed a genetic association study on individuals with dilated cardiomyopathy and found that CFTR containing I556V mutation, which causes a channel defect, is associated with the disease. Similar to well-studied channel-defective CFTR mutants, CFTR I556V mRNA failed to restore cardiac dysplasia in mutant embryos. Conclusions: The present study reveals an important role for the CFTR ion channel in regulating cardiac development during early embryogenesis, supporting the hypothesis that CF-related heart disease results from an intrinsic primary defect in the CF heart.