Role of proteoglycans on testosterone synthesis by purified Leydig cells from immature and mature rats

Generation of Haploid Spermatids on Silk Fibroin-Alginate-Laminin-Based Porous 3D Scaffolds

In vitro production of sperm is a desirable idea for fertility preservation in azoospermic men and prepubertal boys suffering from cancer. In this study, a biocompatible porous scaffold based on a triad mixture of silk fibroin (SF), alginate (Alg), and laminin (LM) is developed to facilitate the differentiation of mouse spermatogonia stem cells (SSCs). Following SF extraction, the content is analyzed by SDS-PAGE and stable porous 3D scaffolds are successfully prepared by merely Alg, SF, and a combination of Alg-SF, or Alg-SF-LM through freeze-drying. Then, the biomimetic scaffolds are characterized regarding the structural and biological properties, water absorption capacity, biocompatibility, biodegradability, and mechanical behavior. Neonatal mice testicular cells are seeded on three-dimensional scaffolds and their differentiation efficiency is evaluated using real-time PCR, flow cytometry, immunohistochemistry. Blend matrices showed uniform porous microstructures with interconnected networks, which maintained long-term stability and mechanical properties better than homogenous structures. Molecular analysis of the cells after 21 days of culture showed that the expression of differentiation-related proteins in cells that are developed in composite scaffolds is significantly higher than in other groups. The application of a composite system can lead to the differentiation of SSCs, paving the way for a novel infertility treatment landscape in the future.

Bilateral asymmetry in bullfrog testes and fat bodies: correlations with steroidogenic activity, mast cells number and structural proteins

In seasonal breeders, such as amphibians, testicular functions depend on complex processes that change according to seasonality, including Leydig cell (LC) differentiation and lipid-dependent steroidogenesis, extracellular proteins remodeling and actin-dependent cellular dynamics. Speculating that fat bodies (FB) could support some of these processes in L. catesbeianus, we evaluated bilaterally the FB weights, correlating them to testicular parameters such as weight, testosterone (T) immunoexpression, mast cells (MC) number, vascularization and structural proteins. In an attempt to better understand the testicular asymmetry in amphibians, correlations between these different testicular parameters were also established. Right testes (RT), left testes (LT) and associated FB of bullfrogs were weighed, and testes were processed for light and transmission electron microscopy. Collagen content (COL) and MC number were quantified. T and actin immunoexpressions and vascular areas were measured. Statistical analyses and Pearson's correlation were performed. The LT and its associated FB were heavier than the right ones, and showed intense T and actin immunoexpressions, numerous lipid-rich LC, and greater MC number, COL and vascularization than the RT. Positive correlations were detected between: a) FB and testis weights, b) T immunoexpression and testis and FB weights, c) T and actin immunoexpressions and COL. Otherwise, MC number was inversely correlated to T immunoexpression and COL. In right and left sides, the proportional correlation between T immunoexpression and FB weight suggests that FB-stored lipid amount depends on the steroidogenic demand of its associated testis. Thus, the asymmetry in the testes and FB may be associated, at least in part, to the LC steroidogenic activity, which tends to be more intense in LT than in RT. The results also point to a role of COL and mast cells in the LC differentiation and steroidogenesis. Actin was also greater in LT and correlated with T immunoexpression, indicating that the amount of this structural protein depends on androgenic control. Therefore, the testicular asymmetry in bullfrogs seems to be associated to different morphofunctional processes occurring, bilaterally, at different intensities. In this case, there is a tendency of LT, in association with its FB, to be more active than RT. The findings highlight the FB-testis interplay for the comprehension of reproduction in amphibians.

Androgen-regulated cervical ripening: a structural, biomechanical, and molecular analysis

OBJECTIVE

Androgens regulate biomechanical responses in load-bearing tissues. Evidence suggests that androgens may play a role in the cervix. We hypothesized that androgens directly regulate cervical remodeling by altering both collagen structure and proteoglycan composition.

STUDY DESIGN

Cervical resistance was evaluated using the cervical creep method after the administration of intravaginal dihydrotestosterone or oral flutamide. Microstructural changes in collagen were evaluated by transmission electron microscopy and polarized light birefringence. Proteoglycan expression was evaluated by reverse transcription-polymerase chain reaction for the core proteins (decorin, biglycan, fibromodulin, aggrecan, versican) and fluorophore-assisted carbohydrate analysis.

RESULTS

Dihydrotestosterone decreased cervical resistance, whereas flutamide inhibited the decline in cervical resistance, compared with vehicle controls. Flutamide was associated with higher levels of organized collagen and increased aggrecan expression with a greater proportion of chondroitin/dermatan sulfate glycosaminoglycans. Flutamide inhibited the increase in hyaluronan.

CONCLUSION

Androgens appear to play a role in regulating cervical resistance by altering proteoglycan content. Structural analysis indicates that flutamide may alter collagen fibril organization and/or structure.

Type IV collagen induces down-regulation of steroidogenic response to gonadotropins in adult rat Leydig cells involving mitogen-activated protein kinase

We have previously shown that type IV collagen (alpha1 (IV) and alpha2 (IV) collagen chains) (Col-IV) inhibits testosterone (T) production by Leydig cells (LC). The aim of this study was to analyze mechanism/s by which Col-IV exerts this effect. No significant differences in the specific binding of hCG to LH/hCG receptors in LC cultured on uncoated or Col-IV coated plates were observed. An inhibition of cAMP production in hCG-stimulated LC cultured on Col-IV was detected. The inhibition exerted by Col-IV on T production in response to hCG was also observed when cells were stimulated with 8Bromo-cAMP. In addition, conversion of steroid precursors to T in LC cultured on uncoated and Col-IV coated plates was similar. On the other hand, we detected an increase of ERK1/2 phosphorylation in hCG-stimulated LC cultured on Col-IV. Genistein added to LC cultures reduced the ability of Col-IV to increase ERK1/2 phosphorylation and reverted the inhibitory effect of Col-IV on T production. An inhibitor of MEK, PD98059 added to LC cultures also reverted the inhibitory effect of Col-IV on T production. A decrease of steroidogenic acute regulatory protein (StAR) expression in hCG-stimulated LC cultured on Col-IV coated plates that could be reverted by addition of PD98059 to the cultures was also demonstrated. All together these results suggest that Col-IV inhibits T production in LC by binding to integrins, activating ERK1/2, decreasing cAMP production and decreasing StAR expression.

Effect of extracellular matrix proteins on in vitro testosterone production by rat Leydig cells

The aim of this study was to detect the effect of extracellular matrix (ECM) proteins on rat Leydig cell shape, adhesion, expression of integrin subunits and testosterone production, in vitro. Leydig cells isolated from adult rats were cultured on plates uncoated or coated with different concentrations of laminin-1, fibronectin, or type IV collagen in the presence or absence of hCG for 3 or 24 hr. A significant increase of cell adhesion and of alpha3, alpha5, and beta1 integrin subunit expression was observed when cells were cultured on ECM proteins, compared to those grown on uncoated plates. Leydig cells cultured on glass coverslips coated with ECM proteins for 24 hr exhibited elongated shapes with long cell processes (spreading), while cells cultured on uncoated plates showed few cell processes. A significant decrease in testosterone production was observed when basal and hCG-stimulated Leydig cells were cultured for 3 or 24 hr on plates coated with type IV collagen (12 and 24 microg/cm(2)) compared to uncoated plates. A significant though a slighter decrease in testosterone production was also observed in cells cultured on plates coated with fibronectin (12 and 24 microg/cm(2)), compared to uncoated plates. Laminin-1 did not modify testosterone production under basal or hCG stimulated conditions. These results suggest that ECM proteins are able to modulate Leydig cell steroidogenesis, in vitro.

Histochemical study of the interstitial tissue in scrotal and abdominal boar testes

The present study describes the glycosidic content of the interstitial tissue in testes from healthy boars and from unilateral and bilateral abdominal cryptorchid boars using lectin histochemistry. The Leydig cells of healthy boars contained glycans with fucosyl, mannosyl, glucosyl, neuraminic acid and galactosyl residues, which have structural and transport functions, and participate in androgen synthesis and in cell regulation. Unilateral cryptorchidism induced high glucosyl and low galactosyl content in the Leydig cells of scrotal testes, resulting in impaired androgen production. In abdominal testes, the Leydig cells exhibited increased amounts of glucosyl and reduced amounts of galactosyl and neuraminic acid residues, resulting in defective cell regulation and lack of androgen synthesis. In healthy boars, the extracellular glycans contained fucosyl, galactosyl, glucosyl and neuraminic acid residues, which confer viscoelasticity on the interstitial tissue and participate in substrate transport, hormone binding and cell-cell interaction. Unilateral cryptorchidism did not induce anomalies in extracellular glycans in scrotal testes, but unilateral and bilateral cryptorchidism resulted in an increased content of fucosyl and galactosyl, and a decreased content of glucosyl and neuraminic acid residues in abdominal testes, leading to reduced viscoelasticity and defective substrate transport across the extracellular matrix.

Cytology of the interstitial tissue in scrotal and abdominal testes of post-puberal boars

The interstitial tissue of the testes from healthy boars, and unilateral and bilateral abdominal cryptorchid boars was examined by light and transmission electron microscopy. The left and right testes of healthy boars, and the left (scrotal) testis of unilateral cryptorchid boars had abundant mature Leydig cells, few fibroblasts and mast cells, scarce and small blood vessels, and little lymphatic areas. The right (abdominal) testis of unilateral cryptorchid boars contained abundant Leydig cells, fibroblasts and erythrocytes, scarce mast cells, and frequent blood vessels; Leydig cells exhibited either a mature but degenerative appearance or an immature appearance, and fibroblasts displayed immaturity signs. The interstitial tissue of the left (abdominal) testes of bilateral cryptorchid boars had small blood vessels surrounded by erythrocytes, lymphocytes, and few plasma cells, and abundant mature and immature Leydig cells, immature fibroblasts, and mast cells. Mature Leydig cells showed mid or advanced degeneration, and immature Leydig cells displayed either non-degenerative or degenerative patterns. The right (abdominal) testes of bilateral cryptorchid boars contained scarce immature Leydig cells in advanced degeneration, large fibrous and adipose areas, and blood vessels. These results indicated that unilateral abdominal cryptorchidism affect neither the structural nor the cytologic features of the interstitial tissue in scrotal testes. Unilateral and bilateral cryptorchidism induced abnormal differentiation of Leydig cells and fibroblasts leading to decreased steroid production and increased collagenization in abdominal testes.