Testin Induction: The Role of Cyclic 3′,5′-Adenosine Monophosphate/Protein Kinase A Signaling in the Regulation of Basal and Lonidamine-Induced Testin Expression by Rat Sertoli Cells1

Abstract

Results of previous in vitro and in vivo studies have illustrated that the expression of testin by Sertoli cells is tightly associated with the disruption of Sertoli-germ cell junctions. In the present study, treatment of rats with cadmium chloride (CdCl(2)), which disrupted the inter-Sertoli tight junctions, failed to induce any changes in testicular testin expression. In contrast, lonidamine, an antispermatogenic drug that rearranges the Sertoli cell membrane microfilament structure causing a disruption of Sertoli-germ cell adhesion junctions, induced a drastic increase in testicular testin expression when administered orally. Lonidamine-induced Sertoli cell testin expression involved both ongoing RNA and de novo protein synthesis. Basal testin expression remained stable during the 27-h incubation with actinomycin D but required de novo protein synthesis in vitro. An inhibitor of protein kinase A, Rp-cAMPS, caused a 50% inhibition of Sertoli cell testin expression at 10 microM within 24 h. A biphasic response was noted in testin expression when forskolin was included in the Sertoli cell culture, and high concentrations of cAMP analogues (1 mM) rapidly reduced testin expression. However, lonidamine can abolish the inhibitory effect of cAMP analogues on Sertoli cell testin expression. These results illustrate that the induction of testin expression may involve several signal transduction pathways.

Testin and actin are key molecular targets of adjudin, an anti-spermatogenic agent, in the testis

“…What is known is that testin is a signaling molecule whose expression surges during apical ES disassembly 23,28,51 (its level is also highest at late stage VIII of the seminiferous epithelial cycle 27 ) and that testin binds actin strongly unknown. Herein, we utilized a specific anti-adjudin antibody and co-immunoprecipitation to show that actin-myosin and testin bind adjudin, which destabilizes actin filament bundles as visualized by electron microscopy 39 and leads to premature germ cell loss (i.e., pseudo-spermiation).…”

Anchoring Junctions As Drug Targets: Role in Contraceptive Development

“…3). After decades of morphological and biochemical studies, we know that Sertoli cells isolated from rat testes become polarized and establish functional junctions when they are plated on a reconstituted basement membrane such as Matrigel at high cell density (ϳ0.5-1.0 ϫ 10 6 cells/cm 2 ) in a two-dimensional environment (Chung et al, 1999;Grima and Cheng, 2000;Wong et al, 2000;Chung and Cheng, 2001;Lee et al, 2003). We also know that Sertoli cells cultured under these conditions are functionally similar to those found in the testis in vivo, because they secrete transferrin, androgen binding protein (ABP), testin, and ␣ 2 -macroglobulin in a polarized fashion (Grima et al, 1992).…”

Regulation of blood-testis barrier dynamics: an in vivo study

“…at 3 mg/kg body weight (b.w.) to induce BTB damage as previously described (Hew et al, 1993b;Setchell and Waites, 1970;Grima and Cheng, 2000). Thereafter, rats were killed by CO2 asphyxiation at 1, 3,5,7,12,16,20,24,48, and 96 hours after CdCl2 treatment, testes were removed from the scrotum, and the weight of each testis was recorded (Table 1).…”