Male infertility often results from the inability of spermatozoa to reach and fertilize an oocyte. These properties are acquired by the sperm cells as they transit through the epididymal tubule. However, this small organ is understudied and as such male infertility often remains unexplained.
The different epithelial cell types (clear, principal and basal cells) that line the lumen of the epididymis work in a concerted manner to maintain a unique acidic environment that contributes to the maturation and storage of spermatozoa in a dormant state. Our study aims at decoding this complex intercellular communication network.
Moreover, we recently uncovered unexpected roles for proton secreting clear cells in sperm maturation and immune defense. We showed that clear cells express mRNA transcripts and proteins that are acquired by the maturing sperm, and they establish close interactions with luminal spermatozoa via newly described “nanotubes”. Another important aspect of epithelial cell function is related to the fact that they constitute the first line of defense against infections. In the epididymis, a balance between tolerance to immunogenic spermatozoa and immune activation against pathogens must be maintained. In mechanistic studies, we found that clear cells respond to the presence of bacterial antigens in vivo by expressing chemokines, which induce the recruitment of macrophages into the epididymis. These recent findings thus revealed the participation of clear cells as sensors and mediators of inflammation. Characterizing these novel properties is another active research theme in our lab.
We use a multidisciplinary approach including high-resolution laser scanning confocal immunofluorescence microscopy, 3D reconstruction of single cells, intravital multiphoton microscopy, luminal perfusion of the epididymis in vivo, and monitoring of live cells in vivo and in vitro.