Balough, J. L. | Search bioRxiv

bioRxiv2026

Epithelial stem cells in the premenopausal human vagina

The vagina undergoes physiologic changes across the menstrual cycle, pregnancy, birth and menopause. Most women will experience vaginal dysfunction at some point during their lives and treatment options are limited. The cyclic regeneration of the vaginal epithelium during each menstrual cycle suggests it is a stem-cell based tissue; however, human vaginal epithelial stem cells (veSCs) have not been identified. We utilized in vitro colony forming and organoid assays to confirm that cells in the human vaginal epithelium have self-renewal and differentiation potential. Specifically, we determined that stem cell activity resides in the ITGA6+ and NGFR+ fractions of the basal epithelium. We performed single-cell RNA sequencing to identify the distinct cellular compartments of the full thickness human vagina, including spatially distinct populations comprising layers of the stratified vaginal epithelium. Markers of these cells within the vaginal epithelium were validated by immunohistochemistry. CD9+ITGA6+NGFR+ and CD9+ITGA6+NGFR- cells were capable of efficient colony formation but only the CD9+ITGA6+NGFR+ fraction produced organoids containing basal, intermediate and superficial layers of the vaginal epithelium. We characterized the premenopausal human vagina at single cell resolution, validated markers and assays to test veSC developmental potential, and identified putative stem cells that may open new avenues for treating vaginal dysfunction.

cell biology↗

bioRxiv2025

Inorganic profiles of preimplantation embryos reveal a role for zinc in blastocyst development

Elements such as iron, copper and zinc play essential roles in the mammalian oocyte, egg, and embryo, however among these metals, zinc plays unique regulatory roles. Temporal fluctuations in zinc concentrations drive reproductive milestones such as meiotic resumption, egg activation, and initiation of the mitotic cell cycle. Roles for zinc in late preimplantation embryo development, have not been well characterized. Using a quantitative element approach we report the inorganic profiles of mouse embryos progressing through the late blastocyst stage. We find that blastocysts, like oocytes and eggs, and distinct to somatic cells, maintain higher levels of zinc than copper and iron. All three of these essential metals are more abundant in the inner cell mass, which contains the population of pluripotent stem cells that give rise to the fetus, relative to the trophectoderm which gives rise to the placenta and extraembryonic tissues. To test whether zinc abundance was associated with mitotic progress and cell fate lineage, we perturbed zinc homeostasis during blastocyst formation by artificially raising intracellular zinc concentrations with zinc pyrithione. This treatment during the morula-to-blastocyst transition when cell fate lineages emerge resulted in an elevation of zinc in the ICM. This treatment did not impact cell number but did increase expression of the pluripotency and epiblast marker, Nanog. These results demonstrate that the inorganic profiles of the late preimplantation embryo retain elemental hallmarks of earlier developmental stages and perturbation of zinc levels alters pluripotency gene expression in the blastocyst. In BriefZinc plays important regulatory roles during oocyte maturation, fertilization and early embryo development; however, the role of zinc in the late preimplantation embryo is unknown. In this study, inorganic profiling of mouse embryos reveal zinc levels are higher than copper and iron in the late blastocyst and zinc supplementation during the morula-to-blastocyst alters expression of pluripotency marker, Nanog.

developmental biology↗