Expression and regulation of transforming growth factor-beta 1 messenger ribonucleic acid and protein in cultured porcine Leydig and Sertoli cells.

Abstract

In the present work, the expression and secretion of transforming growth factor-beta 1 (TGF beta 1) by immature pig Leydig and Sertoli cells were investigated. Both cell types express two TGF beta 1 mRNA transcripts of 2.5 and 3.5 kilobases, and the levels were 2.6-fold higher in Leydig than in Sertoli cells. In the latter cells, mRNA levels were enhanced when cultured cells were stimulated by epidermal growth factor and phorbol ester (4-beta-phorbol 12-myristate 13-acetate) and significantly decreased by FSH and testosterone. Using a polyclonal antibody raised against a synthetic peptide that corresponded to the carboxyl-terminal region of TGF beta 1 and recognized this peptide, but not TGF beta 2 or TGF beta 3, specific immunostaining of both Leydig and Sertoli cells was demonstrated in situ, after cell isolation, and during culture. The immunostaining was more marked in Leydig cells than in Sertoli cells. Western blot analysis of Leydig or Sertoli cell-conditioned medium demonstrated a band of 25 kilodaltons, which was shifted to 12.5 kilodaltons under reducing conditions. Using the mink lung epithelial cell bioassay for TGF beta 1, we could demonstrate the presence of TGF beta 1-like activity in Leydig and Sertoli cell-conditioned media after acid treatment, but not before activation. The inhibitory effects of both pure TGF beta 1 and acidified conditioned medium were almost completely blunted by the TGF beta 1 antibody. The amounts of TGF beta 1 secreted by Sertoli and Leydig cells were not significantly different and varied between 400-800 pg/48 h.10(6) cells. These studies demonstrate for the first time that both pig Leydig and Sertoli cells express TGF beta 1 mRNA, and the TGF beta 1-like activity secreted by these cells corresponds to TGF beta 1. As TGF beta 1 has been demonstrated to have strong effects on testicular cells, in particular on Leydig cell functions, it is suggested that local secreted TGF beta 1 may play a role in the autocrine/paracrine regulation of testicular functions.

TGF-.BETA.1 System in Leydig Cells. Part I: Effect of hCG and Progesterone

“…in agreement with other reports in different experimental models [4,8,17]. Previous studies have shown adenomatous growth of Leydig cells in prepubertal hCG+ mice, but only slight hypertrophy and hyperplasia were detected at adult age [10,11].…”

“…Testosterone and FSH suppress the expression of TGF-β1 in cultured porcine Leydig and Sertoli cells, respectively [8], and hCG stimulates TGF-βRI and TGF-βRII expression in cultured porcine Leydig cells, whereas steroid hormones have no effect [9]. New genetically modified animal models have proven important in increasing our understanding of testicular pathologies associated with gonadotropin function.…”

Testicular defense systems: immune privilege and innate immunity

“…The transforming growth factors (TGF) b12b3 are constitutively expressed in the testis and predominantly produced by SCs. 87,88 As an anti-inflammatory factor, TGF-b1 is implicated in the protection of islet b-cell grafts after co-transplantation with SCs. 27 SCs also abundantly express activin A and B.…”

TGF-.BETA.1 System in Leydig Cells. Part II: TGF-.BETA.1 and Progesterone, Through Smad1/5, are Involved in the Hyperplasia/hypertrophy of Leydig Cells

“…Dev. 56: 400-404, 2010) GF-β influences steroidogenesis [1] and also modulates Leydig cell DNA synthesis by regulating Leydig cell proliferation [2]. Moreover, either the absence or overexpression of this factor affects male reproductive function, supporting the participation of TGF-β signaling pathways in the orchestration of testicular development and spermatogenesis [3][4][5].…”