CRISP (cysteine rich secretory proteins) as novel regulators of epididymal epithelium differentiation and immunotolerance

GUILLERMO CARVAJAL; NICOLÁS BRUKMAN; MARIANA WEIGEL MUÑOZ; MARÍA AGUSTINA BATTISTONE; LIVIA LUSTIG; SYLVIE BRETON; PATRICIA CUASNICÚ

Jornada; Reunión conjunta de Sociedades de Biociencias; 2017

Epididymal CRISP1 and CRISP4 associate with the sperm surfaceduring maturation and are key mediators of the fertilization process.Whereas knockout (KO) males for each of these molecules are fertile,double KO (DKO) for CRISP1/CRISP4 exhibit impaired fertility.Histological studies of DKO epididymides revealed the existenceof two groups of mice: one with a phenotype identical to controls(Group 1) and one exhibiting epididymal epithelium defects (i.e. vacuoles,evaginations) and abnormal presence of immune cells in boththe interstitium and lumen (Group 2) not detected in the single KOs.Based on this, in the present work we investigated the mechanismsunderlining the inflammatory phenotype of CRISP1/CRISP4 DKOmice. Analysis of the epididymides from Group 2 showed both anincrease in intraluminal pH and a reduction in sperm viability fromcaput to cauda not observed in controls. RT-qPCR for different immunomodulatormolecules revealed higher levels of Il-6 and Il-10as well as a downregulation of Tgf-β in Group 2 DKO. None of thedescribed alterations were detected in animals from Group 1. Interestingly,immunofluorescence experiments using specific markersfor different epididymal epithelial cells revealed damaged and evenlack of principal cells, few and shorter basal cell projections and absenceof rows of clear cells in mice from both groups, resembling thephenotype of immature mice. These observations support the ideathat initial defects in epididymal epithelium differentiation might be responsible for the inflammatory response detected in epididymidesfrom Group 2. Altogether, these results revealed the relevance ofCRISP for epididymal epithelium differentiation and their key role inmaintaining the characteristic immunotolerance of the epididymidis.Keywords: epididymis, sperm, epithelium, inflammation