The regulation of cell junctions (tight junctions, adhesion junctions) in the testis is critical for the process of spermatogenesis (sperm production). Suppression of the major endocrine regulators of spermatogenesis, FSH and androgens, disrupts intercellular adhesion, particularly between developing germ cells and the somatic Sertoli cells.
A key focus of our group is the developmental step called spermiation which includes the final release of sperm, where we have shown that suppression of hormone action prevents sperm release in rats, monkeys and men.
We are utilising genomic and proteomic approaches to study the adhesion-related genes between Sertoli cells and developing spermatids in order to identify the regulatory pathways by which Sertoli cell-germ cell adhesion is regulated (see Regulation of Sperm Release).
We are also investigating the blood-testis barrier, which is a permeability barrier functioning to sequester germ cells undergoing meiotic and post-meiotic differentiation from the vascular environment. Tight junctions found between Sertoli cells are the major component of this barrier in the adult testis. Sertoli cell tight junctions are required for fertility and we know that their disruption leads to germ cell atresia and cessation of spermatogenesis. We have conclusively shown that FSH and androgen controls the blood-testis barrier, which involves the tight junctions between Sertoli cells. As the blood-testis barrier is essential for the production of viable sperm, we have focussed our efforts on determining if regulation of the tight junctions is similar in humans.