Expression of tumor necrosis factor-alpha in mouse spermatogenic cells.

Abstract

Enriched fractions of spermatogenic cells were isolated by unit gravity sedimentation and analyzed both for the presence of secreted tumor necrosis factor-alpha (TNF alpha) in vitro by bioassay and for the presence of TNF alpha mRNA by Northern blot analysis. Small quantities of bioactive TNF alpha were consistently detected in medium conditioned by round spermatid fractions. Both pachytene spermatocyte and round spermatid fractions contained RNA that hybridized with murine cDNA probes for TNF alpha, with pachytene spermatocytes containing a normal 1.9-kilobase (kb) transcript, while round spermatids contained principally an approximately 2.8-kb transcript. Both the normal size transcript and the larger haploid-specific transcript were enriched when total RNA from pachytene spermatocyte and round spermatid fractions was passed through an oligo(dT) column. The normal 1.9-kb transcript within pachytene spermatocytes could be induced by exposing the spermatogenic cells to lipopolysaccharides in vitro, yet the approximately 2.8-kb transcript within round spermatids appeared uninduced by LPS treatment. In situ hybridization for the TNF alpha message by using digoxigenin label antisense TNF alpha riboprobe labeled pachytene spermatocytes, round spermatids, and presumptive interstitial macrophages. Spermatogonia and elongating spermatids as well as other interstitial cells were unlabeled or very lightly labeled. Hybridization of 16-day-old prepuberal testis resulted in the labeling of spermatocytes and presumptive interstitial macrophages. RNA from Sertoli cells, but not pachytene spermatocytes or round spermatids, hybridized with human TNF alpha receptor p60 probe in Northern blot analysis. These results are consistent with the working hypothesis that spermatids release TNF alpha, which is detected by Sertoli cells and may serve as a paracrine factor, regulating an as yet unidentified process in spermatogenesis.

Coxsackie and adenovirus receptor (CAR) is a product of Sertoli and germ cells in rat testes which is localized at the Sertoli–Sertoli and Sertoli–germ cell interface

“…Reduced expression of CAR or E-cadherin was most evident among carcinomas under progression, which was frequently accompanied by cytokine response in vivo [39,40]. In the testes, TNFα is secreted by both Sertoli and germ cells [41,42]. Our group has conducted several studies on cytokine mediated restructuring of the junctional complex in spermatogenesis [41,[43][44][45].…”

Testicular defense systems: immune privilege and innate immunity

“…31,32 Fas ligand (FasL) is abundantly expressed in male germ cells. 33 FasL-induced apoptosis of Fas-bearing lymphocytes is an important mechanism for suppression of immune responses.…”

TNF-α and IFN-γ Regulate Expression and Function of the Fas System in the Seminiferous Epithelium

“…Furthermore, this result may also suggest that in vivo, at the physiologically low concentrations of TNF-␣ produced by germ cells, the soluble antiapoptotic form of Fas is secreted in the seminiferous tubule as a survival factor. TNF-␣ and IFN-␥ are cytokines present in the seminiferous tubule (21,50) and are strongly up-regulated in inflammatory disease; they may control apoptosis in the testis in both physiological and pathological conditions by modulating Fas-mediated cell death. Finally, because FasL is abundantly expressed in the testis (17), whereas Fas protein expression is low (18), the modulation of Fas levels may be important in the control of Fas-mediated apoptosis in this organ.…”

“…TNF-␣ is a testicular paracrine factor, known to be produced by germ cells (21), that induces transferrin release from Sertoli cells (22) and is an important proinflammatory cytokine that induces IL-6 production and ICAM-1 and VCAM-1 expression in Sertoli cells (4). The transduction mechanisms by which these biological effects are obtained in Sertoli cells have been studied extensively (23,24).…”