Novel role of proton-secreting epithelial cells in sperm maturation and mucosal immunity

• Published in: Journal of cell science Vol. 133; no. 5
• Main Authors: Battistone, Maria A, Spallanzani, Raul German, Mendelsohn, Alexandra C, Capen, Diane, Nair, Anil V, Brown, Dennis, Breton, Sylvie
• Format: Journal Article
• Language: English
• Published: England The Company of Biologists Ltd 01.03.2020
• Subjects: RNA sequencing; Post-testicular regulation; Sperm maturation; V-ATPase; Male fertility; Immune regulation; Male reproductive tract
• ISSN: 0021-9533; 1477-9137
• DOI: 10.1242/jcs.233239

Epithelial cells are immune sensors and mediators that constitute the first line of defense against infections. Using the epididymis, a model for studying tubular organs, we uncovered a novel and unexpected role for professional proton-secreting 'clear cells' in sperm maturation and immune defense. The epididymal epithelium participates in the maturation of spermatozoa via the establishment of an acidic milieu and transfer of proteins to sperm cells, a poorly characterized process. We show that proton-secreting clear cells express mRNA transcripts and proteins that are acquired by maturing sperm, and that they establish close interactions with luminal spermatozoa via newly described 'nanotubes'. Mechanistic studies show that injection of bacterial antigens induces chemokine expression in clear cells, followed by macrophage recruitment into the organ. Injection of an inflammatory intermediate mediator (IFN-γ) increased expression in clear cells, revealing their participation as sensors and mediators of inflammation. The functional diversity adopted by clear cells might represent a generalized phenomenon by which similar epithelial cells decode signals, communicate with neighbors and mediate mucosal immunity, depending on their precise location within an organ.