EXPRESSION OFβ-CATENIN IN HUMAN TESTES WITH SPERMATOGENIC DEFECTS

Abstract

& b-catenin is a multifunctional molecule that functions in intercellular adhesion and signal transduction during assembly of AJs between Sertoli cells as well as between Sertoli cells and germ cells. To assess changes in the testicular b-catenin in male infertility conditions, testicular tissues from obstructive azoospermia with normal spermatogenesis, spermatogenic arrest (SA) and Sertoli cell-only syndrome (SCO) patients were examined for immunohistochemical localization of b-catenin. In normal spermatogenic tissue, expression of b-catenin was largely found in the Sertoli cell-germ cell (primarily spermatocytes) contact areas. Interestingly, perinuclear localization of b-catenin was found in spermatocytes and spermatids. In spermatogenic arrest, b-catenin in cell contact areas between Sertoli cells and germ cells was greatly decreased, but perinuclear b-catenin in spermatocytes was not. In SCO, weak or negligible immunoreactivity of b-catenin was found in cell contacts between Sertoli cells. Nuclear localization of b-catenin was found in myotubular cells in all samples. Taken together, altered expression of b-catenin in cell contacts within the seminiferous epithelia in spermatogenic arrest and SCO suggests that interactions between Sertoli cells and germ cell are crucial for expression of b-catenin, and thus functional development of AJs in seminiferous epithelia in human testis. It should be also emphasized that perinuclear b-catenin in germ cells may play a specific role in spermatogenesis.

DHT deficiency perturbs the integrity of the rat seminiferous epithelium by disrupting tight and adherens junctions

“…In the maturating Sertoli cells, the iNOS expression dramatically increased compared to eNOS and in germ cells the iNOS mRNA plunged, whereas the eNOS mRNA level rose during maturation. Taken together, these findings illustrate the different responses of NOS isoforms in Sertoli and germ cells during testes maturation, and suggest the important biological function of NO to maintain testis function [50].…”

“…Lee et al [50] suggested that interactions between Sertoli cells and germ cell are crucial for expression of b-catenin. So, the reduction of its immunoexpression in our study could be correlated with a decrease of the germ cell adhesive capacity.…”

Claudin-11 expression increased in spermatogenic defect in human testes

“…Similarly, claudin-11 is overexpressed and dislocated from the BTB in Sertoli cells in testicular intraepithelial neoplasia (18). Also, SCO showed functional immaturity of Sertoli cells and altered b-catenin expression and TGF-b signaling (19)(20)(21)(22). Together, assembly of claudin-11 to the inter-Sertoli TJs might be inactive in SCO due to a lack or insufficiency of interactions between Sertoli cells and germ cells.…”

Role of β-Catenin in Post-Meiotic Male Germ Cell Differentiation

“…This cellular interaction is facilitated by adherens junctional complexes such as ectoplasmic specializations (ES), which is critical for both adhesion and signaling between Sertoli cells and between Sertoli cells and germ cells [7]. The importance of Sertoli cell-germ cell interaction is evidenced by the fact that abnormal or disrupted ES contributes to spermatid sloughing and oligospermia in pathological conditions associated with reduced fertility potential, including varicocele, hyperprolactinemia, diabetes and idiopathic oligospermia [5], [30], [31]. Despite its critical importance, underlying mechanisms that regulate Sertoli cell-germ cell adhesion and signaling remains to be completely understood.…”

“…Similarly, aberrant activation of β-catenin leads to impaired development of primordial germ cells [4]. β-catenin expression also persists in Sertoli and germ cells of the adult testis [5], [6]. In particular, β-catenin is found in the ectoplasmic specialization (ES), a testis-specific adherens junction formed between Sertoli cells at the basal compartment (basal ES), site of the blood-testis barrier, as well as between Sertoli/germ cells at the adluminal compartment (apical ES) of the seminiferous epithelium [7].…”