Endothelial ZBTB16: a molecular shield against cardiac aging

BACKGROUND AND AIMS: Aging significantly increases the risk of cardiovascular disease, characterized by progressive cardiac dysfunction. The vascular niche is crucial for maintaining cardiac homeostasis, yet endothelial cell (EC) impairment during aging remains poorly understood. This study investigates epigenetically regulated mechanisms underlying EC-dependent cardiac aging and identifies a critical role for zinc finger and BTB domain-containing protein 16 (ZBTB16). METHODS: Chromatin accessibility (snATAC-seq) and transcriptomic (snRNA-seq) analyses of aged hearts were performed to define age-related regulatory changes. Functional studies using genetic models were performed to assess cardiac aging phenotypes. In vitro assays examined EC senescence, secretory profiles, and effects of ZBTB16-deficient EC supernatants on fibroblasts, cardiomyocytes, and neurons. Overexpression experiments in vitro and in vivo tested whether ZBTB16 mitigates aging-associated dysfunction. RESULTS: Aged hearts exhibited decreased chromatin accessibility and reduced ZBTB16 expression in both humans and mice. Zbtb16 deletion in young mice, including Zbtb16-haploinsufficient and endothelial-specific knockout mice, led to premature aging, diastolic dysfunction, and increased secretion of pro-fibrotic and inflammatory factors. ZBTB16-deficient EC supernatants activated fibroblasts, induced cardiomyocyte hypertrophy, and impaired neuronal sprouting. Overexpression of ZBTB16 reversed these effects in senescent ECs and aged mice and reduced diastolic dysfunction. Mechanistic studies identified nuclear receptor-interacting protein 1 as a downstream target suppressed by ZBTB16, thereby limiting fibroblast activation and pro-fibrotic signalling. CONCLUSIONS: ZBTB16 preserves endothelial integrity and vascular niche homeostasis, protecting against aging-associated cardiac dysfunction. Its loss promotes EC senescence and fibrosis, whereas restoring its expression may represent a therapeutic strategy to improve cardiac function and reduce cardiovascular disease risk during aging.