Mathur P P, Grima J, Mo M Y, Zhu L J, Aravindan G R, Calcagno K, O'Bryan M, Chung S, Mruk D, Lee W M, Silvestrini B, Cheng C Y
Population Council, Center for Biomedical Research, New York, NY 10021, USA.
Biochem Mol Biol Int. 1997 Jun;42(2):217-33. doi: 10.1080/15216549700202611.
In the seminiferous epithelium, germ cell development behind the blood-testis barrier involves continual degradation and renewal of inter-testicular cell junctions. This allows: (i) the translocation of developing germ cells from the basal lamina to the adluminal compartment during spermatogenesis, and (ii) the eventual release of mature spermatids into the tubular lumen during spermiation. Throughout spermatogenesis, cellular debris must also be removed from the epithelium Thus, it is conceivable that proteases, protease inhibitors, and cell junctional components are involved in these events. The present study sought to examine whether testicular cells can express multiple cathepsin mRNAs given that these proteases are involved in the degradation and processing of proteins as well as in tissue regeneration. By using total RNA isolated from primary cultures of Sertoli, Leydig, and germ cells for reverse-transcription and polymerase chain reaction (RT-PCR), the mRNAs of cathepsin B, C, D, H, L, and S were shown to be expressed by Sertoli and Leydig cells, whereas germ cells isolated from adult rats expressed all of the above cathepsin mRNAs except cathepsin D. Throughout postnatal development and maturation, the testicular steady-state mRNA levels of cathepsin B, C, D, L, and S remain relatively unchanged with the exception of cathepsin H whose mRNA level increased during maturation and peaked at 45-60 days of age. Using lonidamine, an anti-spermatogenic drug which is known to induce premature release of germ cells without affecting Leydig cell function by disrupting the inter-Sertoli-germ cell junctions, we have examined the differential expression of these cathepsin mRNAs in the testis at the time of extensive tissue restructuring. It was noted that the expression of cathepsin L and S in the testis increased significantly concomitant with the disappearance of elongate spermatids whereas the expression of cathepsin B, C, D, and H increased significantly when most of the round spermatids and spermatocytes were depleted. These results illustrate the intricate inter-relationship between these proteases in the testis during maturation and tissue restructuring.
在生精上皮中，血睾屏障后方的生殖细胞发育涉及睾丸间质细胞间连接的持续降解和更新。这使得：（i）在精子发生过程中，发育中的生殖细胞从基膜向管腔间腔室移位，以及（ii）在精子形成过程中，成熟精子最终释放到管腔中。在整个精子发生过程中，细胞碎片也必须从上皮中清除。因此，可以想象蛋白酶、蛋白酶抑制剂和细胞连接成分参与了这些过程。鉴于这些蛋白酶参与蛋白质的降解和加工以及组织再生，本研究旨在检测睾丸细胞是否能表达多种组织蛋白酶mRNA。通过使用从支持细胞、间质细胞和生殖细胞原代培养物中分离的总RNA进行逆转录和聚合酶链反应（RT-PCR），结果显示支持细胞和间质细胞表达组织蛋白酶B、C、D、H、L和S的mRNA，而从成年大鼠分离的生殖细胞表达除组织蛋白酶D之外的上述所有组织蛋白酶mRNA。在出生后的整个发育和成熟过程中，组织蛋白酶B、C、D、L和S的睾丸稳态mRNA水平相对保持不变，除了组织蛋白酶H，其mRNA水平在成熟过程中升高，并在45 - 60日龄时达到峰值。使用洛硝哒唑，一种抗生精药物，已知其通过破坏支持细胞 - 生殖细胞间连接诱导生殖细胞过早释放而不影响间质细胞功能，我们在广泛组织重塑时检测了这些组织蛋白酶mRNA在睾丸中的差异表达。值得注意的是，随着长形精子细胞的消失，睾丸中组织蛋白酶L和S的表达显著增加，而当大多数圆形精子细胞和精母细胞耗尽时，组织蛋白酶B、C、D和H的表达显著增加。这些结果说明了这些蛋白酶在睾丸成熟和组织重塑过程中的复杂相互关系。
