Notch signaling in the epididymal epithelium regulates sperm motility and is transferred at a distance within epididymosomes

Abstract

SUMMARYSpermatozoa undergo sequential maturation changes during their transit along the epididymis. These changes are modulated by the epididymal epithelium and require a finely tuned gene expression. The Notch cell signaling pathway is a major regulator of cell fate decisions in several tissues, including the testis. Here, we evaluated the transcription and expression patterns of Notch components (Notch1-3, Dll1, Dll4, and Jagged1) and effectors (Hes1-2 and Hes5) in the adult mouse epididymis, and evaluated the role of Notch signaling in the epididymis through its in vivo blockade following administration of an inhibitor (DAPT). Notch components and effectors were dynamically transcribed and expressed in the epididymis and vas deferens, each segment exhibiting a specific combination of epithelial receptor/ligand/effector expression patterns. Nuclear detection of Notch effectors indicates that Notch signaling was active. Notch components (but not effectors) were identified in the cytoplasmic droplet of spermatozoa, in a dynamic and specific pattern along the epididymis. In addition, Notch components were identified within large and small vesicles in the epididymal lumen. A purified population of these membranous vesicles from different epididymal segments was obtained, and through dot blot analysis, it was confirmed that Notch components were carried within these vesicles in a dynamic pattern along the epididymal lumen. We hypothesize that these vesicles (epididymosomes) allow Notch signaling at distance from epididymal epithelial cells to spermatozoa. DAPT-induced in vivo Notch signaling blockade, although showing a low efficiency, disrupted the expression patterns of Notch components and effectors in the epididymal epithelium and in spermatozoa, and significantly decreased sperm motility, although not affecting male fertility. These results prompt for a regulatory role of Notch signaling in epididymal epithelial function and sperm maturation.

MicroRNA expression profiles in the seminal plasma of nonobstructive azoospermia patients with different histopathologic patterns

“…Hes genes are the most studied Notch effector genes, and Hes1 and Hes5 are the most represented genes in mammals (47). The Notch signaling pathway plays important roles in the development and differentiation of male germ cells (58)(59)(60). The pathway components can regulate the pace of spermatogenesis at several points and control proliferative and differentiated cellular events that take place during the spermatogenic cycle (61,62).…”

Tissue regeneration and the epididymal stem cell

“…Constitutively expressed Notch1 in adult mice resulted in hyperplasia with the absence of fully differentiated cells, and an absence of basal cells (Lupien et al ., ). Interestingly, Notch pathway components and effector genes are expressed along the epithelium of the epididymis by all cell types under normal conditions (Murta et al ., ).…”

Analysis of the Temporal Patterning of Notch Downstream Targets during Drosophila melanogaster Egg Chamber Development

“…For instance, a study identified that interactions between epithelial cells in mice require proper sequential interaction of signaling pathways, among these most notably, the Notch pathway. This research also showed the transcription and expression patterns of various Notch components, suggesting that timing may play a role in the interactions of downstream targets 8 . In Drosophila, researchers also reported the importance of temporal regulation of neuroblasts for the cell fate and survival of Notch-mediated neurons 9,10 .…”