Multiomic analysis reveals that polyamines alter G. vaginalis-induced cervicovaginal epithelial cell dysfunction
An anaerobe-dominant, Lactobacillus-deplete cervicovaginal microbiome is associated with adverse reproductive outcomes. Gardnerella vaginalis, a common cervicovaginal anaerobe, alters cervicovaginal epithelial cell function, resulting in inflammatory immune responses and epithelial barrier breakdown. Specific host-microbial mechanisms inducing this epithelial dysfunction remain unknown. Here we show microbe-specific alterations in cervicovaginal epithelial cell metabolite profiles where G. vaginalis, but not Lactobacillus crispatus, increases polyamine biosynthesis. Pretreatment with polyamines (putrescine, spermidine and spermine) globally shifts G. vaginalis-induced transcriptomic profiles. Alterations in transcripts encoding enzymes responsible for polyamine synthesis and catabolism provides further evidence that G. vaginalis modifies polyamine biosynthesis. Additionally, polyamine-mediated transcriptomic changes include genes related to bacterial defense, inflammation, and epigenetic processes. Polyamines mitigate G. vaginalis-induced inflammatory responses through reduction of cytokines, chemokines, and matrix metalloproteinases. The ability of cervicovaginal metabolites to alter microbe-mediated changes in epithelial cell function suggests that metabolite-microbe interactions are critical mediators of epithelial defense against a Lactobacillus-deplete microbiota. Overall design: Human cervicovaginal epithelial cell lines (Ectocervical, Endocervical, and Vaginal) were exposed to Gardnerella vaginalis (107 CFU/well) for 24 hours to characterize microbe-induced transcriptional responses. To assess the impact of vaginal polyamines on these responses, cells were pretreated for 4 hours with putrescine (4 mM), spermidine (400 µM), or spermine (400 µM) prior to G. vaginalis exposure. Control conditions included untreated cells and G. vaginalis exposure without polyamines. Total RNA was extracted, ribosomal RNA–depleted, and sequenced using the CORALL total RNA-seq protocol on an Illumina NovaSeq platform.