Gut microbiota-dependent increase in phenylacetic acid induces endothelial cell senescence during aging

Abstract Endothelial cell (EC) senescence plays a crucial role in the development of cardiovascular diseases in aging population. Gut microbiota alterations are emerging as significant factors present in cellular senescence associated with aging. However, little is known about how aging-related changes in gut microbiota are causally implicated in EC senescence. Here we show that gut microbiota-dependent phenylacetic acid (PAA) and its derivative, phenylacetylglutamine (PAGln), are elevated in a human aging cohort (TwinsUK, n=7,303) and in aged mice. Metagenomic analyses revealed a marked increase in the abundance of PAA-producing microbial pathways (PPFOR and VOR), which were positively associated with the abundance of Clostridium sp. ASF356, higher circulating PAA concentrations, and endothelial dysfunction in old mice. We found that PAA potently induces EC senescence and attenuates angiogenesis. Mechanistically, PAA increases mitochondrial H 2 O 2 generation, which aggravates IL6-mediated HDAC4 translocation and thereby upregulates VCAM1. In contrast, exogenous acetate, which was reduced in old mice, rescues the PAA-induced EC senescence and restores angiogenic capacity through markedly alleviating the SASP and epigenetic alteration. Our studies provide direct evidence of PAA-mediated crosstalk between aging gut microbiota and EC senescence and suggest a microbiota-based therapy for promoting healthy aging. Highlights Aging-related gut microbiota alterations contribute to a marked elevation of plasma PAA and PAGln in humans and mice Clostridium sp. ASF356 contributes to PPFOR-mediated PAA formation in aged mice Gut-derived PAA promotes endothelial senescence and impairs angiogenesis PAA induces mitochondrial H 2 O 2 generation, by which drives epigenetic alterations and SASP in ECs Acetate rescues PAA-induced EC senescence and mitochondrial dysfunction Acetate improves angiogenesis by reducing HDAC4 phosphorylation and SASP