Androgens and Postmeiotic Germ Cells Regulate Claudin-11 Expression in Rat Sertoli Cells

Abstract

In the present study we investigated whether fetal exposure to flutamide affected messenger and protein levels of claudin-11, a key Sertoli cell factor in the establishment of the hemotesticular barrier, at the time of two key events of postnatal testis development: 1) before puberty (postnatal d 14) during the establishment of the hemotesticular barrier, and 2) at the adult age (postnatal d 90) at the time of full spermatogenesis. The data obtained show that claudin-11 expression was inhibited in prepubertal rat testes exposed in utero to 2 and 10 mg/kg x d flutamide. However, in adult testes, the inhibition was observed only with 2, and not with 10, mg/kg x d of the antiandrogen. It is shown here that these differences between prepubertal and adult testes could be related to dual and opposed regulation of claudin-11 expression resulting from positive control by androgens and an inhibitory effect of postmeiotic germ cells. Indeed, testosterone is shown to stimulate claudin-11 expression in cultured Sertoli cells in a dose- and time-dependent manner (maximum effect with 0.06 microm after 72 h of treatment). In contrast, postmeiotic germ cells potentially exert a negative effect on claudin-11 expression, because adult rat testes depleted in spermatids (after local irradiation) displayed increased claudin-11 expression, whereas in a model of cocultured Sertoli and germ cells, spermatids, but not spermatocytes, inhibited claudin-11 expression. The apparent absence of claudin-11 expression changes in adult rat testes exposed to 10 mg/kg x d flutamide therefore could result from the antagonistic effects of 1) the inhibitory action of the antiandrogen and 2) the stimulatory effect of the apoptotic germ cells on claudin-11 expression. Together, due to the key role of claudin-11 in the hemotesticular barrier, the present findings suggest that such regulatory mechanisms may potentially affect this barrier (re)modeling during spermatogenesis.

Intercellular adhesion molecule-1 is a regulator of blood–testis barrier function

“…Cells were seeded at a density of 0.5610 6 cells/cm 2 in 12-well plates for lysate preparation, RNA isolation and overexpression experiments, at a density of 1.2610 6 cells/cm 2 in Millicell inserts (Millipore Corp., Billerica, MA) for transepithelial electrical resistance (TER) measurements and overexpression experiments, or at a density of 0.05610 6 cells/ cm 2 on round glass coverslips (18 mm; Thomas Scientific, Swedesboro, NJ) for immunofluorescent staining. It is worth noting that functional junctions were assembled and maintained in control Sertoli cells cultured at all densities used in this study, a conclusion that is based on nearly two decades of research from this and other laboratories Chung et al, 1999;Dym and Papadopoulos, 1992;Florin et al, 2005;Hadley et al, 1987;Janecki et al, 1991;Janecki and Steinberger, 1986;Lie et al, 2011;Lui et al, 2001;Siu et al, 2003;Su et al, 2010b;Tung and Fritz, 1993). All substrata were coated with Matrigel TM basement membrane matrix as previously described (Xiao et al, 2011).…”

Blood–testis barrier and Sertoli cell function: lessons from SCCx43KO mice

“…testosterone, transcription factors, FSH and/or GC (Mruk & Cheng 2004, Yan et al 2008, Lie et al 2009, Morrow et al 2010. Interestingly, postmeiotic GC have been shown to have an inhibitory effect on CLAUDIN11 expression in rat seminiferous epithelium, whereas spermatogonia and premeiotic spermatocytes have no effect (Florin et al 2005).…”

Claudins and germ cell tumors

“…In normal seminiferous epithelium claudin 11 is located at the basal compartment and the distribution is similar to ZO1 and ZO2 in this location (45). Claudin 1, 3 and 11 expression in Sertoli cells of mouse and rat testis appears to be regulated by androgens (46,47,48). Also gonadotropins regulate the expression of tight junctional proteins such as claudin 11 and occludin (49).…”

“…FSH and TNF alpha inhibits claudin 11 expression in Sertoli cell culture (82). Testosterone increases claudin 11 mRNA expression in a dose dependent manner (47). The influence of antiandrogenic flutamide is complex (47).…”

“…Testosterone increases claudin 11 mRNA expression in a dose dependent manner (47). The influence of antiandrogenic flutamide is complex (47). Fetally administered flutamide in mice resulted in prepubertal decrease of claudin 11 in Sertoli cells but the inhibition in adult testes was dose dependent, lower doses resulting in decreased expression (47).…”