Extracellular vesicles are involved in the paracrine communication between epithelial cells in different regions of the domestic cat epididymis

Sperm maturation depends on exposure to specific microenvironments within the different segments of the epididymis, but mechanisms underlying how these microenvironments are produced or maintained are not well understood. We hypothesize that epididymal extracellular vesicles (EVs) could play a role in this process, and therefore set out to test whether the EVs from different regions of the epididymis can serve as a form of paracrine communication between epithelial cells. Domestic cat tissues were used to develop a reproducible in vitro culture system for corpus epididymis explants that were then exposed to EVs collected from upstream (i.e., caput) segments. The impacts of different culture or exposure conditions were compared by analyzing the morphology, apoptosis, transcriptional activity, and gene expression in the explants. Here, we report the development of the first in vitro culture system for epididymal tissue explants in the domestic cat model. Using this system, we found that EVs from the caput segment have a significant effect on the transcriptional profile of tissue from the corpus segment (1,233 differentially expressed genes due to EV supplementation). Of note, expression of genes associated with regulation of epithelial cell differentiation and cytokine signaling in the epididymis were regulated by the presence of EVs. Together, our findings comprise the first report of paracrine control of segmental gene regulation by epididymal EVs in any species. These results contribute to a better understanding of epididymis biology and could lead to techniques to enhance or suppress male fertility. To determine the effect of caput EVs on the transcriptome of corpus epididymis explants, we cultured corpus explants with and without EV supplementation and also included fresh tissue controls. RNA was extracted, and sequenced.