A novel protein B2URF3 from Akkermansia muciniphila increased by intermittent fasting alleviates vascular calcification

Vascular calcification (VC) is a major contributor to cardiovascular morbidity and mortality, yet effective therapies are lacking. Here, we show that alternate-day intermittent fasting (IF1:1) attenuates vitamin D-induced VC in mice, whereas a 5:2 regimen is ineffective. The protective effect of IF1:1 is gut microbiota-dependent, particularly through enrichment of Akkermansia muciniphila (Akk). Microbiota-derived extracellular vesicles (EVs) function as nano-scale mediators that bypass the spatiotemporal constraints of bacterial survival to facilitate long-distance communication with host cells, providing a crucial pathway for downstream mechanistic investigation. Akk-derived EVs (Akk-EVs) are internalized by vascular smooth muscle cells (VSMCs), suppressing osteogenic differentiation and calcification in vitro and in vivo. Proteomic analysis identified B2URF3 as a highly enriched functional protein in Akk-EVs and Akk, which interacts with Aldehyde Dehydrogenase 1 Family Member B1 (ALDH1B1) to inhibit VSMC osteogenic transdifferentiation. Clinically, reduced fecal Akk abundance and lower serum B2URF3 levels were observed in patients with coronary calcification. These findings define a gut-vascular axis by which IF1:1 mitigates VC and nominate Akk-EVs and B2URF3 as potential therapeutic targets and biomarkers.