Amuc_1473 Links Gut Microbes to Skeletal Homeostasis and Counteracts Multifactorial Osteoporosis

Emerging evidence suggests that gut microbiota-derived signals can influence distant organs including the skeleton, yet the key microbial effectors remain elusive. Here, we identify Amuc_1473, a previously uncharacterized protein enriched in extracellular vesicles (EVs) from the commensal bacterium Akkermansia muciniphila (Akk), as a critical mediator of gut-bone communication. Amuc_1473 directly promotes osteogenesis and suppresses osteoclastogenesis by binding to negative elongation factor E (NELF-E) and ribosomal protein L26 (RPL26), regulators of transcriptional pausing and mRNA translation, respectively. Notably, Amuc_1473 levels decline in bone and circulation under diverse pro-osteoporotic conditions-including aging, estrogen deficiency, mechanical unloading, high-fat diet, smoking, alcohol, and chronic stress-paralleling reductions in Akk and its EVs. Intermittent fasting robustly restores Akk abundance, Amuc_1473 levels, and bone quality in these models, via enhanced mucin production. Our findings establish Amuc_1473 as a microbial effector that systemically regulates bone homeostasis, offering a translatable strategy to prevent or treat multifactorial osteoporosis.