Exosomes derived from Bcl-2-engineered iPSC-cardiomyocytes mitigate aortic valve calcification and inhibit...

Calcific Aortic Valve Disease (CAVD) is a progressive cardiovascular disorder, the pathological processes of which are correlated with cell apoptosis, inflammatory response, and osteogenic remodeling of valve interstitial cells. Presently, there exists no effective pharmacological treatment or intervention to impede or reverse the advancement of this disease. Systematically identifying key molecular biomarkers and their regulatory pathways is crucial for the formulation of novel therapeutic strategies. Exosomes, functioning as a novel drug delivery system, can transport specific functional molecules. In this research, proteomic and transcriptomic analyses disclosed an imbalance in the bcl2/bax apoptosis regulatory axis in CAVD. Further exploration indicated that miR-132, which IL-1β regulates, is dysregulated and associated with increased cellular apoptosis. To re-establish homeostasis in apoptotic and inflammatory pathways, engineered exosomes overexpressing bcl2, derived from induced pluripotent stem cell-derived cardiomyocytes (iPSC^bcl2-CM-Exos), were constructed. In vitro experiments demonstrated that iPSC^bcl2-CM-Exos significantly diminished the apoptosis rate of cardiomyocytes and valve interstitial cells induced by H₂O₂. Modulations in apoptosis-related markers further supported their potential anti-apoptotic effect. In vivo, iPSC^bcl2-CM-Exos are safe and effective. They upregulate bcl2, downregulate bax, restore miR-132 expression, and inhibit the abnormal elevation of IL-1β, thereby notably reducing the apoptosis of valve interstitial cells, enhancing cardiac function, and alleviating leaflet thickening and fibrosis. This study identifies an imbalance in the bcl2/bax axis as a key molecular characteristic of CAVD. It demonstrates that bcl2-engineered exosomes can simultaneously target apoptotic and inflammatory pathways, thereby presenting a promising cell-free therapeutic strategy for CAVD.