Recombinant Amuc_1100 from Akkermansia muciniphila modulates tight junction-associated protein in vaginal epithelial cells.

Amuc_1100, an outer membrane protein of the mucin-degrading commensal bacterium Akkermansia muciniphila, is known to strengthen intestinal epithelial barrier integrity, with reports suggesting a potential involvement of Toll-like receptor 2 (TLR2). Its role in the vaginal epithelial barrier, however, remains unexplored. In this study, recombinant Amuc_1100 was expressed in a baculovirus-insect cell system and purified by immobilized metal affinity chromatography (IMAC). Purified Amuc_1100 exhibited concentration-dependent binding to recombinant TLR2 in ELISA. In VK2/E6E7 vaginal epithelial cells, Amuc_1100 treatment did not alter viability across the tested concentrations, confirming the absence of cytotoxicity. Western blot analysis demonstrated that Amuc_1100 treatment significantly increased the expression of tight junction-associated proteins, including Zonula Occludens-1 (ZO-1), Claudin-1 (CLDN-1), and Claudin-4 (CLDN-4), under basal conditions. Furthermore, stimulation with lipopolysaccharide (LPS) or zymosan A markedly reduced ZO-1 levels, whereas co-treatment with Amuc_1100 restored expression under both conditions. Collectively, these findings provide preliminary evidence that recombinant Amuc_1100 modulates tight junction-associated protein expression in vaginal epithelial cells. However, additional functional barrier assays, mechanistic studies, and in vivo validation are required to further evaluate its potential as a postbiotic candidate.