Interaction between microbes and host in sows vagina of early pregnancy

Extensive researches explored the causes of embryo losses during early pregnancy by analyzing interaction mechanisms in sows uterus, ignoring the importance of the lower reproductive tract in pregnancy development regulation. Despite recent progress in understanding the diversity of vaginal microbes under different physiological states, the dynamic of sows vaginal microbiotas during pregnancy and the interaction between vaginal microbes and the host are poorly understood. Here, we performed a comprehensive analysis of sows vagina microbial communities in early pregnancy coupled to overall patterns of vaginal mucosal epithelium gene expression. The vagina microbiota was analyzed by 16s rRNA or metagenome sequencing and the vaginal mucosal epithelium transcriptome by RNA sequencing, followed by integration of the data layers. We find that the sows vaginal microbiotas in early pregnancy develop dynamically, and there is a homeostasis balance of Firmicutes and Proteobacteria. Subsequently, we identify two pregnancy-specific communities, which play diverse roles. The microbes in vagina stimulate the epithelial cells, while vaginal epithelium changes its structure and functions in response to stimulation. These changes produce specific inflammation responses to promote pregnancy development. Our findings demonstrate the interaction between microbes and host in sows vagina of early pregnancy to promote pregnancy development, meanwhile, providing a reference dataset for the study of targeted therapies of microbial homeostasis dysregulation in the female reproductive tract.