Abstract 256: Cardiac Fibroblast-derived Exosomes Mediate Endothelial Dysfunction and Heart Failure

Objective: Endothelial cells (ECs) play critical role to maintain the normal heart function. Others and we have previously shown that stress-induced chronic inflammation mediates ECs dysfunction and restoration of IL10 (an anti-inflammatory cytokine) preserve ECs function, but, its mechanism is not clearly known. Here we hypothesized that activated cardiac fibroblasts-derived exosomes (FB-Exo) mediates cardiac ECs dysfunction and leads for cardiac pathology and IL10 treatment negatively regulates the FB-Exo contents and thus improve ECs function and biology. Methods: Human aortic endothelial cells (HAECs), human umbilical endothelial cells (HUVEC) and cardiac endothelial cells were cultured in EC growth media. Cells were treated with TGFβ/IL10/FB-exo. Exosomes were isolated from fibroblast condition media by ultracentrifugation and characterized by nanosight & electron microscopy. Results: TGFβ treatment significantly induced ECs dysfunction as shown by Matrigel assay, real-time Q-PCR and immunostaining data. IL10 treatment significantly restored TGFβ-induced endothelial dysfunction as evident by immunostaining and western blot (CD31, Smad2/3 and αSMA) data. Furthermore, exosomes were isolated from saline/AngII treated neonatal heart fibroblast conditioned media by ultracentrifugation and characterized. We found that exosomes-derived from Ang II/TGF treated fibroblast were enriched with TGFβ and collagen-1α. Matrigel tube formation and quantitative PCR results suggest that activated fibroblasts secrete factors which triggered endothelial dysfunction (Matrigel/qPCR). Intriguingly, Ang II treated fibroblast-derived exosomes strongly promote endothelial cell differentiation to fibroblasts like cells. Conclusions: Taken together, this study demonstrates that Ang II/TGFb treated fibroblasts-derived exosomes are enriched in pro-fibrotic factors and can lead to endothelial dysfunction and promotes cardiac fibrosis in PO myocardium. Ongoing investigations using molecular approaches will provide a better understanding on the mechanistic and therapeutic aspects of IL10 and modification of fibroblast-derived exosomal content on endothelial function and cardiac fibrosis failing heart.