Developmental regulation of connexin 43 expression in fetal mouse testicular cells

Abstract

Multiple connexins have been identified in testicular cells. Several lines of evidences indicate that, among them, connexin 43 (Cx43) may be unique for control of gonad development and spermatogenesis. To date, however, it is not known whether Cx43 is expressed in the fetal testis and what possible types of cellular interactions mediated by this connexin are critical to male fertility. In the present work, expression of Cx43 was investigated at various developmental ages in cryosections from mouse testis by using specific antibodies against Cx43. In serial or double-labeled sections, Cx43 localization was compared with immunocytochemical distribution of steroidogenic enzyme, 3␤-hydroxysteroid dehydrogenase (3␤HSD), Mullerian inhibitory hormone (MIH), and germinal nuclear cell antigen (GCNA1), which are specific markers, respectively, of interstitial Leydig, Sertoli, and germinal cells. Sections were analyzed by fluorescence microcopy. We found that Cx43 immunofluorescence (IF) was uniformly distributed in the undifferentiated gonad at 11.5 days post coitus (dpc) and in cells of the mesonephric tubules. In the undifferentiated gonad, Cx43 was localized between primordial germ cells and somatic cells. At 12.5 dpc, when the gonad has undergone sexual differentiation, in the interstitium Cx43 was localized in Leydig cells and in the seminiferous cord it was localized between adjacent Sertoli cells. In Leydig and Sertoli cells, Cx43 labeling increased at 14.5, 16.5, and 18.5 dpc. From day 12.5 up to 18.5 dpc, Cx43 was also localized in cell borders between germinal and Sertoli cells. In conclusion, this study demonstrates that from the earliest stages of gonadal development, Cx43 is expressed in the principal cell types that participate in the control of male fertility. It also shows that Cx43 expression in Leydig and Sertoli cells increase during fetal life. Finally, it provides evidence that, throughout embryonic life, Cx43 forms gap junctions between Sertoli and germinal cells. Anat Rec 264: [237][238][239][240][241][242][243][244][245][246] 2001.

Testicular connexin 43, a precocious molecular target for the effect of environmental toxicants on male fertility

“…In fetal and newborn rats, and at the time of initiation of spermatogenesis, Cx43 is present between Leydig cells, between Sertoli cells and between Sertoli and germ cells. [41][42][43] During this critical period of testicular development, Cx43 is first detected as separate dots or a filiformlike network (Fig. 2), which shifts from the apical to the basal regions of seminiferous tubules.…”

Wt1negatively regulates β-catenin signaling during testis development

“…In our studies, claudin 11 and occludin mRNA levels were not significantly reduced in mutant testis. Connexin 43 (CX43) is a predominant testicular gap junction protein, which is involved in the formation of gap junctions between adjacent Sertoli cells and between Sertoli and germ cells in the seminiferous epithelium (Batias et al, 1999;Decrouy et al, 2004;Perez-Armendariz et al, 2001). CX43 is essential for the control of Sertoli cell proliferation and maturation.…”

A Sertoli cell-specific connexin43 knockout leads to altered interstitial connexin expression and increased Leydig cell numbers

“…Cx43 expression is observed in both LC populations. However, it is expressed continuously in fetal LC from their earliest differentiation stage onward but is regulated in adult LC in an age-and function-dependent manner from birth to adulthood (Risley et al 1992;Perez-Armendariz et al 2001;Bravo-Moreno et al 2001). The ultimate fate of fetal LC is not yet entirely understood.…”