A Comparison of the Effects of Testicular Maturation and Aging on the Stage-Specific Expression of CP-2/Cathepsin L Messenger Ribonucleic Acid by Sertoli Cells of the Brown Norway Rat1

Abstract

We have examined the effects of maturation and aging on expression of cyclic protein-2 (CP-2)/cathepsin L mRNA by rat Sertoli cells. During maturation (25-68 days of age) there was a significant, 7.6-fold increase in CP-2/cathepsin L mRNA. There was a significant, 2.9-fold increase in SGP-2 mRNA during the same period. In situ hybridization analysis demonstrated that stage-specific expression of CP-2/cathepsin L mRNA developed between 30 and 35 days. By 64 days of age, this transcript was only detectable in Sertoli cells within stage VI-VII tubules. Northern blot analysis of 23-mo-old testes revealed statistically significant decreases in total testis contents of CP-2/cathepsin L and SGP-2 mRNAs (4- and 3-fold, respectively) in testes that lacked germ cells but not in aged testes with a full complement of germ cells. In situ hybridization analysis revealed high amounts of CP-2/cathepsin L mRNA in all aged tubules that were losing germ cells via apoptosis, regardless of the stage of the cycle. Immunocytochemical analysis demonstrated that in these aged, regressing tubules, CP-2/cathepsin L protein became concentrated in dying or dead germ cells.

Expression of Cathepsin L in Human Testis Under Diverse Infertility Conditions

“…Also in situ hybridization analysis revealed high amounts of cathepsin L mRNA in all aged tubules that were losing germ cells via apoptosis, regardless of the stage of the cycle. Immunohistochemical analysis demonstrated that in these aged, regressing tubules, cathepsin L protein became concentrated in drying or dead germ cells [4]. Additionally, this stage-specific expression of cathepsin L might result from multiple interactions between Sertoli cells and their adjacent germ cells [14].…”

“…Most cathepsins are lysosomal and each is involved in cellular metabolism, participating in various events such as peptide biosynthesis and protein degradation. Cathepsin L is a 38 kDa protein that is most closely related to cathepsin H and implicated in the complex process of spermatozoa production and maturation in the testis and epididymis [3,4,9]. In rat testis, the cathepsin L expression in Sertoli cells is closely related to spermatogenic stage of germ cells [4,5,10,15].…”

“…Cathepsin L is a 38 kDa protein that is most closely related to cathepsin H and implicated in the complex process of spermatozoa production and maturation in the testis and epididymis [3,4,9]. In rat testis, the cathepsin L expression in Sertoli cells is closely related to spermatogenic stage of germ cells [4,5,10,15]. In primary culture of testicular cells of rat, the expression of cathepsin L significantly increased concomitant with the disappearance of elongated spermatids, whereas the expression of cathepsin B, C, D, and H significantly increased when most of the round spermatids and spermatocytes were depleted [5].…”

Stage-Specific Expression of Genes Associated with Rat Spermatogenesis: Characterization by Laser-Capture Microdissection and Real-Time Polymerase Chain Reaction1

“…Cathepsin-L is a cysteine protease expressed by Sertoli cells [39] and Leydig cells [40] and is thought to be involved in the turnover of Sertoli cell-elongate spermatid and Sertoli-Sertoli cell junctions [40]. Previous data by Northern blot analysis [30] and in situ hybridization [31] has shown that cathepsin-L mRNA is undetectable at stage II and is greatest during stages VI-VII, after which it is down-regulated. Similarly, cathepsin-L immunostaining is present during stages V-VIII in Sertoli cells, being strongest during stages VI-VII [41], and is not found in other stages.…”

“…A series of genes previously shown to be stage specific were studied, including cathepsin-L [30,31], transition protein-1 (TP-1) [17,32], cyclic-AMP response element modulator-(CREM-) [33], and androgen receptor (AR) [16,34,35]. In addition, the stage-specificity of two cell adhesion molecules, N-cadherin and ␤1-integrin, for which available evidence suggests regulation by FSH and T [36][37][38] was investigated.…”