CRISP (CYSTEINE RICH SECRETORY PROTEINS) AS NOVEL REGULATORS OF EPIDIDYMAL EPITHELIUM DIFFERENTIATION AND IMMUNOTOLERANCE

CARVAJAL G; BRUKMAN NG; WEIGEL-MUÑOZ M; BATTISTONE A; LUSTIG L; BRETON S; CUASNICU PB

Congreso; Reunión Conjunta Sociedades Biomédicas; 2017

Epididymal CRISP1 and CRISP4 associate with the sperm surface during 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 existence of 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 both the interstitium and lumen (Group 2) not detected in the single KOs. Based on this, in the present work we investigated the mechanisms underlining the inflammatory phenotype of CRISP1/CRISP4 DKO mice. Analysis of the epididymides from Group 2 showed both an increase in intraluminal pH and a reduction in sperm viability from caput to cauda not observed in controls. RT-qPCR for different immunomodulator molecules revealed higher levels of Il-6 and Il-10 as well as a downregulation of Tgf-β in Group 2 DKO. None of the described alterations were detected in animals from Group 1. Interestingly, immunofluorescence experiments using specific markers for different epididymal epithelial cells revealed damaged and even lack of principal cells, few and shorter basal cell projections and absence of rows of clear cells in mice from both groups, resembling the phenotype of immature mice. These observations support the idea that initial defects in epididymal epithelium differentiation might be responsible for the inflammatory response detected in epididymides from Group 2. Altogether, these results revealed the relevance of CRISP for epididymal epithelium differentiation and their key role in maintaining the characteristic immunotolerance of the epididymidis.