Expression of cathepsin L in human testis under diverse infertility conditions

The cathepsin family of proteolytic enzymes play an important role in the remodeling seminiferous epithelia in rodent testis. In an effort to uncover the cathepsin L expression in diverse pathological conditions in human testis, the immunohistochemical localization of cathepsin L was conducted in human testis under diverse male infertility condition including spermatogenic hypoplasia and testis cancer. In seminiferous tubule of normal, non-obstructive azoospermic, decreased spermatogenesis, and maturation arrest conditions, cathepsin L was found in both germ cells and Sertoli cells. In contrast, there was no visible expression of cathepsin L in seminiferous tubule tissues from Sertoli cell-only syndrome, spermatogenic hypoplasia, and testicular cancer. Our result suggests that the cross-talk between germ cells and Sertoli cells is crucial for the control of cathepsin L expression in human testis. The absence of expression of cathepsin L in germ cell cancer emphasizes that cathepsin L expression in Sertoli cells is regulated by functional germ cells in human testis.