Abstract 362: Role of Dysregulated Exosomal MiRNAs in Functional Impairment of Cardiac Endothelial Cells

Abstract

Objective: Endothelial cells (ECs) play critical role to maintain the normal heart function. It is shown that fibroblast-derived exosomes have the ability to enhance cardiac myocytes hypertrophy in pressure-overloaded myocardium. However, their effect on endothelial cell function has not been studied. Others and we have previously shown that stress-induced chronic inflammation induces cardiac fibroblasts and mediates endothelial cells dysfunction. Here we hypothesized that activated cardiac fibroblasts-derived exosomes (FB-Exo) mediates cardiac ECs dysfunction and leads for cardiac pathology and restoring the altered FB-Exo contents will improve endothelial cells function and biology. Methods: We cultured mouse primary endothelial cells in EC growth media. Cells were treated with fibroblasts-derived-Exo. Exosomes were isolated from fibroblast condition media by ultracentrifugation and characterized by nanosight & electron microscopy. Results: Fibroblasts were significantly activated by TGFβ treatment as shown by qPCR and western blot (smad2/3, p-Smad2/3, p38, p-p38) data. Endothelial cells dysfunction as shown by Matrigel assay, real-time Q-PCR and western data (eNOS and Hif1α) data was observed in TGFβ-FB-Exo treatment endothelial cell. MTT, TUNEL and migration assay also followed the same trend as TGFβ-FB-Exo treatment significantly induced endothelial cell death and inhibits its proliferation and migration. Furthermore, microRNA array and PCR analysis revealed dysregulation of miR-132-3p, miR-2001-3p and miR-125b-5p in TGFβ-FB-Exo treated endothelial cells. Conclusions: Taken together, this study demonstrates that TGFβ treated fibroblasts-derived exosomes are enriched in pro-fibrotic factors and can lead to endothelial dysfunction and promotes cardiac fibrosis in PO myocardium. In future study, we will modulate the target miRs in fibroblasts to see whether it rescue reparative function of endothelial cell and inhibits cardiac fibrosis in failing heart.