Small extracellular vesicle-mediated adipocyte-cardiomyocyte crosstalk exacerbates heart failure with preserved ejection fraction.

AIMS: Although growing evidence suggests that obesity/central adiposity predisposes to the development and exacerbation of heart failure with preserved ejection fraction (HFpEF), it remains to be clarified whether there is a causal relationship between adiposity and HFpEF pathogenesis. METHODS AND RESULTS: HFpEF was induced in male C57BL/6N mice using a high-fat diet + Nω-nitro-l-arginine methyl ester. Resection or transplantation of visceral adipose tissue (VAT) blunted or exacerbated HFpEF phenotypes, respectively, in mice. VAT from HFpEF mice displayed greater weight and secreted more small extracellular vesicles (sEVs) than those from chow-fed mice. Either systemic inhibition of sEV secretion or VAT-specific knockdown of Rab27b (an indispensable GTPase for sEV secretion) protected against HFpEF. Discovery-driven experiments identified miR-295-3p within sEVs as a possible mediator of the VAT-heart axis, which impaired cardiac autophagy by binding to Ulk1 mRNA. MiR-295-3p antagomir treatment mitigated HFpEF phenotypes. Additionally, neonatal mouse cardiomyocytes (NMCMs) manifested blunted autophagic flux after treatment with plasma sEVs from HFpEF mice. Notably, HFpEF patients displayed downregulated cardiac Ulk1 and autophagy compared with healthy individuals. Restoration of cardiac autophagy with rapamycin or ULK1 overexpression via AAV-9 attenuated the HFpEF phenotype in mice. CONCLUSION: The present work unveils a mechanism whereby obesity promotes HFpEF progression, emphasizing the role of VAT-heart crosstalk. Specifically, VAT-derived sEVs, miR-295-3p, and the resultant disruption of cardiac autophagy contribute significantly to the pathogenesis of HFpEF.