Single-cell transcriptome profiling of the vaginal epithelium reveals the heterogeneity of suprabasal cells.

The integrity of the vaginal epithelium is crucial for women’s reproductive health and for providing protection against HIV and sexually transmitted infections. 1 The vagina is a tubular tract made of fibromuscular and elastic tissue that connects the cervix to the outer genitals. Its main function is to discharge uterine secretions. 2 The vaginal epithelium (VE) is a keratinized, stratified squamous epithelium consisting of three layers: the basal layer, the suprabasal layer, and the apical cornified layer. 3 Estrogens induce the proliferation of basal epithelial cells in the vagina. The suprabasal cells, which are no longer mitogenic, differentiate as they move up through the epithelium. The apical cells undergo keratinization, lose their nuclei and cytoplasm, and eventually shed from the surface. 4 With multiple sexually transmitted diseases posing a significant threat to human health, 5 it is increasingly important to understand how the vaginal epithelium regenerates to maintain homeostasis and how it differs from the neighboring cervical epithelium. In this study, we extracted vaginal tissue from five adult virgin mice and conducted single-cell RNA sequencing (scRNA-seq) on the vaginal epithelium. We obtained a total of 7823 cells and isolated and sequenced