Notch signaling regulates nuclear androgen receptor AR and membrane androgen receptor ZIP9 in mouse Sertoli cells

The Jag2/Notch1 signaling axis promotes sebaceous gland differentiation and controls progenitor proliferation

The sebaceous gland (SG) is a vital appendage of the epidermis, and its normal homeostasis and function is crucial for effective maintenance of the skin barrier. Notch signaling is a well-known regulator of epidermal differentiation, and has also been shown to be involved in postnatal maintenance of SGs. However, the precise role of Notch signaling in regulating SG differentiation in the adult homeostatic skin remains unclear. While there is evidence to suggest that Notch1 is the primary Notch receptor involved in regulating the differentiation process, the ligand remains unknown. Using monoclonal therapeutic antibodies designed to specifically inhibit of each of the Notch ligands or receptors, we have identified the Jag2/Notch1 signaling axis as the primary regulator of sebocyte differentiation in mouse homeostatic skin. Mature sebocytes are lost upon specific inhibition of the Jag2 ligand or Notch1 receptor, resulting in the accumulation of proliferative stem/progenitor cells in the SG. Strikingly, this phenotype is reversible, as these stem/progenitor cells re-enter differentiation when the inhibition of Notch activity is lifted. Thus, Notch activity promotes correct sebocyte differentiation, and is required to restrict progenitor proliferation.

9-cis-retinoic acid signaling in Sertoli cells regulates their immunomodulatory function to control lymphocyte physiology and Treg differentiation

BACKGROUND

Testis is an immune privileged organ, which prevents the immune response against sperm antigens and inflammation. Testicular cells responsible for immune tolerance are mainly Sertoli cells, which form the blood-testis barrier and produce immunosuppressive factors. Sertoli cells prevent inflammation in the testis and maintain immune tolerance by inhibiting proliferation and inducing lymphocyte apoptosis. It has been shown that 9-cis-retinoic acid (9cRA) blocks ex vivo apoptosis of peripheral blood lymphocytes and promotes the differentiation of Treg cells in the gut. However, the role of retinoid signaling in regulating the immune privilege of the testes remains unknown.

OBJECTIVE

The aim of this study was to determine whether 9cRA, acting via the retinoic acid receptors (RAR) and the retinoic X receptors (RXR), controls the immunomodulatory functions of Sertoli cells by influencing the secretion of anti-inflammatory/pro-inflammatory factors, lymphocyte physiology and Treg cell differentiation.

METHODS

Experiments were performed using in vitro model of co-cultures of murine Sertoli cells and T lymphocytes. Agonists and antagonists of retinoic acid receptors were used to inhibit/stimulate retinoid signaling in Sertoli cells.

RESULTS

Our results have demonstrated that 9cRA inhibits the expression of immunosuppressive genes and enhances the expression of pro-inflammatory factors in Sertoli cells and lymphocytes, increases lymphocyte viability and decreases apoptosis rate. Moreover, we have found that 9cRA blocks lymphocyte apoptosis acting through both RAR and RXR and inhibiting FasL/Fas/Caspase 8 and Bax/Bcl-2/Caspase 9 pathways. Finally, we have shown that 9cRA signaling in Sertoli cells inhibits Treg differentiation.

CONCLUSION

Collectively, our results indicate that retinoid signaling negatively regulates immunologically privileged functions of Sertoli cells, crucial for ensuring male fertility. 9cRA inhibits lymphocyte apoptosis, which can be related to the development of autoimmunity, inflammation, and, in consequence, infertility.

Is membrane androgen and estrogen receptor signaling imperative in the governing function of the adrenal cortex in the Eurasian beaver (Castor fiber L.)?

There is a need to fully know the physiology of Eurasian beaver due to its essential role in environmental homeostasis. However, a "human factor" impacts this, including stress conditions and environmental pollution. Adrenal glands protect these all. The regulation of endocrine processes by nonclassical androgen and estrogen signaling, the first and fastest control, is still a matter of research. The specific analyses performed here in mature female and male beaver adrenals contained: anatomical and histological examinations, expression and localization of membrane androgen receptor (zinc transporter, Zinc- and Iron-like protein 9; ZIP9) and membrane estrogen receptor coupled with G protein (GPER), and measurement of zinc (Zn2+) and copper (Ca2+) ion levels and corticosterone levels. We revealed normal anatomical localization, size, and tissue histology in female and male beavers, respectively. Equally, ZIP9 and GPER were localized in the membrane of all adrenal cortex cells. The protein expression of these receptors was higher (p < 0.001) in male than female adrenal cortex cells. Similarly, Zn2+ and Ca2+ ion levels were higher (p < 0.05, p < 0.01) in male than female adrenal cortex. The increased corticosterone levels (p < 0.001) were detected in the adrenal cortex of females when compared to males. The present study is the first to report the presence of nonclassical androgen and estrogen signaling and its possible regulatory function in the adrenal cortex of Eurasian beavers. We assume that this first-activated and fast-transmitted regulation can be important in the context of the effect of environmental physical and chemical stressors especially on adrenal cortex cells. The beaver adrenals may constitute an additional supplementary model for searching for universal mechanisms of adrenal cortex physiology and diseases.

Elevated luteinizing hormone receptor signaling or selenium treatment leads to comparable changes in adrenal cortex histology and androgen-AR/ZIP9 signaling

The importance and regulation of adrenal androgen production and signaling are not completely understood and are scarcely studied. In addition, there is still a search for appropriate animal models and experimental systems for the investigation of adrenal physiology and disease. Therefore, the main objective of the study was to evaluate the effect of luteinizing hormone (LH) signaling and selenium (Se2+) exposure on androgen adrenal signaling via canonical androgen receptor (AR), and membrane androgen receptor acting as zinc transporter (zinc- and iron-like protein 9; ZIP9). For herein evaluations, adrenals isolated from transgenic mice with elevated LH receptor signaling (KiLHRD582G) and adrenals obtained from rabbits used for ex vivo adenal cortex culture and exposure to Se2+ were utilized. Tissues were assessed for morphological, morphometric, and Western blot analyses and testosterone and zinc level measurements.Comparison of adrenal cortex histology and morphometric analysis in KiLHRD582G mice and Se2+-treated rabbits revealed cell hypertrophy. No changes in the expression of proliferating cell nuclear antigen (PCNA) were found. In addition, AR expression was decreased (p < 0.001) in both KiLHRD582G mouse and Se2+-treated rabbit adrenal cortex while expression of ZIP9 showed diverse changes. Its expression was increased (P < 0.001) in KiLHRD582G mice and decreased (P < 0.001) in Se2+-treated rabbits but only at the dose 10 ug/100 mg/ tissue. Moreover, increased testosterone levels (P < 0.05) and zinc levels were detected in the adrenal cortex of KiLHRD582G mice whereas in rabbit adrenal cortex treated with Se2+, the effect was the opposite (P < 0.001).

Androgens and Notch signaling cooperate in seminiferous epithelium to regulate genes related to germ cell development and apoptosis

It was reported previously that in adult males disruption of both androgen and Notch signaling impairs spermatid development and germ cell survival in rodent seminiferous epithelium. To explain the molecular mechanisms of these effects, we focused on the interaction between Notch signaling and androgen receptor (AR) in Sertoli cells and investigate its role in the control of proteins involved in apical ectoplasmic specializations, actin remodeling during spermiogenesis, and induction of germ cell apoptosis. First, it was revealed that in rat testicular explants ex vivo both testosterone and Notch signaling modulate AR expression and cooperate in the regulation of spermiogenesis-related genes (Nectin2, Afdn, Arp2, Eps8) and apoptosis-related genes (Fasl, Fas, Bax, Bcl2). Further, altered expression of these genes was found following exposure of Sertoli cells (TM4 cell line) and germ cells (GC-2 cell line) to ligands for Notch receptors (Delta-like1, Delta-like4, and Jagged1) and/or Notch pathway inhibition. Finally, direct interactions of Notch effector, Hairy/enhancer-of-split related with YRPW motif protein 1, and the promoter of Ar gene or AR protein were revealed in TM4 Sertoli cells. In conclusion, Notch pathway activity in Sertoli and germ cells regulates genes related to germ cell development and apoptosis acting both directly and indirectly by influencing androgen signaling in Sertoli cells.

Analysis of circRNA-miRNA-mRNA regulatory network of embryonic gonadal development in Mulard duck

The aim of the study was to explore the regulatory mechanism of differences in embryonic gonadal development between intergeneric distance hybrid offspring Mulard ducks and parent ducks. The morphological differences gonadal tissues of Muscovy ducks, Pekin ducks and Mulard ducks at 12.5-day embryonic age were observed by sectioning and hematoxylin-eosin (HE) staining. Then followed by transcriptome sequencing to screen for gonadal development-related differentially expressed circRNAs and mRNAs to construct a competitive endogenous RNA (ceRNA) regulatory network. Finally, qRT-PCR and luciferase reporter system were used to verify the sequencing data and targeting relationship of ceRNA pairs. The results showed that the seminiferous tubule lumen of Mulard ducks was not obvious, while there were obvious seminiferous tubules and tubular structures in testis of Pekin ducks and Muscovy ducks, with number and shape indicating maturity. There were 18 upregulated circRNAs and 16 downregulated circRNAs in Mulard ducks and Pekin ducks, respectively, and 39 upregulated circRNAs and 1 downregulated circRNA in Mulard ducks and Muscovy ducks, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis found that genes involves in dorso-ventral axis formation, for example, neurogenic locus notch homolog protein 1 (NOTCH1), were significantly enriched (P < 0.05). The novel_circ_0002265-gga-miR-122-5p-PAFAH1B2 regulatory network was constructed. The qRT-PCR results showed that the sequencing results were reliable. The dual-luciferase reporter assay showed that gga-miR-122-5p exists binding site of circ_0002265 and PAFAH1B2, indicating circ_0002265-gga-miR-122-5p-PAFAH1B2 targeting relationship. In summary, the embryonic gonadal development of intergeneric hybrid Mulard ducks may be regulated by differentially expressed circRNAs and genes, such as novel_circ_0000519, novel_circ_0003537, NOTCH1, FGFR2, PAFAH1B1, and PAFAH1B2, among which circ_0002265-gga-miR-122-5p-PAFAH1B2 may participate in the targeted regulation of gonadal development in Mulard ducks. The findings of this study are helpful for analyzing the mechanism of embryonic gonadal development differences in avians.

Role of chromosomal imbalances in the pathogenesis of DSD: A retrospective analysis of 115 prenatal samples

Differences of sex development (DSDs) are a group of congenital conditions characterized by a discrepancy between chromosomal, gonadal, and genital sex development of an individual, with significant impact on medical, psychological and reproductive life. The genetic heterogeneity of DSDs complicates the diagnosis and almost half of the patients remains undiagnosed. In this context, chromosomal imbalances in syndromic DSD patients may help to identify new genes implicated in DSDs. In this study, we aimed at describing the burden of chromosomal imbalances including submicroscopic ones (copy number variants or CNVs) in a cohort of prenatal syndromic DSD patients, and review their role in DSDs. Our patients carried at least one pathogenic or likely pathogenic chromosomal imbalance/CNV or low-level mosaicism for aneuploidy. Almost half of the cases resulted from an unbalanced chromosomal rearrangement. Chromosome 9p/q, 4p/q, 3q and 11q anomalies were more frequently observed. Review of the literature confirmed the causative role of CNVs in DSDs, either in disruption of known DSD-causing genes (SOX9, NR0B1, NR5A1, AR, ATRX, …) or as a tool to suspect new genes in DSDs (HOXD cluster, ADCY2, EMX2, CAMK1D, …). Recurrent CNVs of regulatory elements without coding sequence content (i.e. duplications/deletions upstream of SOX3 or SOX9) confirm detection of CNVs as a mean to explore our non-coding genome. Thus, CNV detection remains a powerful tool to explore undiagnosed DSDs, either through routine techniques or through emerging technologies such as long-read whole genome sequencing or optical genome mapping.

Claudins: The Newly Emerging Targets in Breast Cancer

Claudin-low breast cancers are recently described entities showing low expression of certain claudins and cell adhesion molecules. Claudins constitute the backbone of tight junctions (TJs) formed between 2 cells. Their dysregulation plays a vital role in tumorigenesis. First part of the article focuses on the role of claudins in the TJ organization, their structural-functional characteristics, and post-transcriptional and translational modifications. The latter part of the review attempts to summarize existing knowledge regarding the status of claudins in breast cancer. The article also provides an overview of the effect of claudins on tumor progression, metastasis, stemness, chemotherapy resistance, and their crosstalk with relevant signaling pathways in breast cancer. Claudins can act as 2-edged swords in tumors. Some claudins have either tumor-suppressive/ promoting action, while others work as both in a context-dependent manner. Claudins regulate many important events in breast cancer. However, the intricacies involved in their activity are poorly understood. Post-translational modifications in claudins and their impact on TJ integrity, function, and tumor behavior are still unclear. Although their role in adverse events in breast cancer is recognized, their potential to serve as relevant targets for future therapeutics, especially for difficult-to-treat subtypes of the above malignancy, remains to be explored.

TGF-β3 induces lactate production in Sertoli cell through inhibiting Notch pathway

BACKGROUNDS

In the testis, spermatocytes and spermatids rely on lactate produced by Sertoli cells (SCs) as energy source. TGF-β3 is one of the generally accepted paracrine regulatory factors of SC-created blood-testis barrier (BTB), yet its role in SC glycolysis and lactate production still remains unclear.

OBJECTIVES

To investigate the effect of TGF-β3 on glycolysis and lactate production in SCs and determine the role of Lgl2 and Notch signaling activity during this process.

MATERIALS AND METHODS

Primary cultured rat Sertoli cells and TM4 cells were treated with different concentrations of TGF-β3. In some experiments, cells were transfected with siRNA specifically targeting Lgl2 and then treated with TGF-β3 or DAPT. Lactate concentration, glucose and glutamine consumption in the culture medium, activity of PFK, LDH, and Gls, ATP level, oxygen consumption, extracellular acidification and mitochondrial respiration complex activity were detected using commercial kits. The protein level of Lgl2, LDH, MCT4, and activity of Akt, ERK, p38 MAPK, and Notch pathway were detected by Western blot. The stage-specific expression of Jagged1 was examined by immunohistochemistry and qPCR after LCM. Spermatogenesis in rat testis injected with recombinant Jagged1 (re-Jagged1) was observed by HE staining and lactate concentration in testis lysate was measured at different day point after re-Jagged1 treatment.

RESULTS

Significant enhancement of lactate concentration was detected in culture medium of both primary SCs and TM4 cells treated with TGF-β3 at 3 or 5 ng/ml. Besides, other parameters of glycolysis, i.e. glucose and Gln consumption, enzyme activity of PFK, LDH, and Gls, displayed different levels of increment in primary SCs and TM4 cells after TGF-β3 treatment. Mitochondria respiration of SCs was shown to decrease in response to TGF-β3. Lgl2, MCT4, activity of ERK and p38 MAPK were up-regulated, whereas Akt and Notch pathway activity were inhibited by TGF-β3. Silencing of Lgl2 in SCs affected lactate production and attenuated the above effects of TGF-β3 on SC glycolysis except for Gln consumption, Gls activity, and activity of Akt, ERK, and p38. DAPT treatment in SCs antagonized glycolysis suppression caused by Lgl2-silencing. In vivo analysis revealed a stage-specific expression of Jagged1 in contrary with TGF-β3. Activating Notch signaling by re-Jagged1 resulted in restorable hypospermatogenesis and lowered lactate level in rat testis.

CONCLUSION

TGF-β3 induces lactate production in Sertoli cell through upregulating Lgl2, which weakened the Notch signaling activity and intensified glycolysis in SCs. Thus, besides the known function of TGF-β3 as the BTB regulator, TGF-β3-Lgl2-Notch maybe considered as an important pathway controlling Sertoli cell glycolysis and spermatogenesis. This article is protected by copyright. All rights reserved.

Modulatory Effects of Estradiol and Its Mixtures with Ligands of GPER and PPAR on MAPK and PI3K/Akt Signaling Pathways and Tumorigenic Factors in Mouse Testis Explants and Mouse Tumor Leydig Cells

The present study was designed to evaluate how estradiol alone or in combination with G protein-coupled estrogen receptor (GPER) agonists and GPER and peroxisome proliferator-activated receptor (PPAR) antagonists alter the expression of tumor growth factor β (TGF-β), cyclooxygenase-2 (COX-2), hypoxia inducible factor 1-alpha (HIF-1α), and vascular endothelial growth factor (VEGF) in mouse testis explants and MA-10 mouse tumor Leydig cells. In order to define the hormone-associated signaling pathway, the expression of MAPK and PI3K/Akt was also examined. Tissue explants and cells were treated with estradiol as well as GPER agonist (ICI 182,780), GPER antagonist (G-15), PPARα antagonist (GW6471), and PPARγ antagonist (T00709072) in various combinations. First, we showed that in testis explants GPER and PPARα expressions were activated by the GPER agonist and estradiol (either alone or in mixtures), whereas PPARγ expression was activated only by GPER agonist. Second, increased TGF-β expression and decreased COX-2 expression were found in all experimental groups of testicular explants and MA-10 cells, except for up-regulated COX-2 expression in estradiol-treated cells, compared to respective controls. Third, estradiol treatment led to elevated expression of HIF-1α and VEGF, while their lower levels versus control were noted in the remaining groups of explants. Finally, we demonstrated the up-regulation of MAPK and PI3Kp85/Akt expressions in estradiol-treated groups of both ex vivo and in vitro models, whereas estradiol in mixtures with compounds of agonistic or antagonistic properties either up-regulated or down-regulated signaling kinase expression levels. Our results suggest that a balanced estrogen level and its action together with proper GPER and PPAR signaling play a key role in the maintenance of testis homeostasis. Moreover, changes in TGF-β and COX-2 expressions (that disrupted estrogen pathway) as well as disturbed GPER-PPAR signaling observed after estradiol treatment may be involved in testicular tumorigenesis.

Follicle-stimulating hormone regulates Notch signalling in the seminiferous epithelium of continuously and seasonally breeding rodents

CONTEXT

Juxtacrine (contact-dependent) communication between the cells of seminiferous epithelium mediated by Notch signalling is of importance for the proper course of spermatogenesis in mammals.

AIMS

The present study was designed to evaluate the role of follicle-stimulating hormone (FSH) in the regulation of Notch signalling in rodent seminiferous epithelium.

METHODS

We explored the effects (1) of pharmacological inhibition of the hypothalamus-pituitary-gonadal (HPG) axis and FSH replacement in pubertal rats, and (2) of photoinhibition of HPG axis followed by FSH substitution in seasonally breeding rodents, bank voles, on Notch pathway activity. Experiments on isolated rat Sertoli cells exposed to FSH were also performed. Gene and protein expressions of Notch pathway components were analysed using RT-qPCR, western blot and immunohistochemistry/immunofluorescence.

KEY RESULTS

Distribution patterns of Notch pathway proteins in bank vole and rat seminiferous epithelium were comparable; however, levels of activated Notch1 and Notch3, hairy/enhancer of split 1 (HES1) and hairy/enhancer of split-related with YRPW motif 1 (HEY1) in bank voles were dependent on the length of the photoperiod. In response to FSH similar changes in these proteins were found in both species, indicating that FSH is a negative regulator of Notch pathway activity in seminiferous epithelium.

CONCLUSIONS

Our results support a common mechanism of FSH action on Notch pathway during onset and recrudescence of spermatogenesis in rodents.

IMPLICATIONS

Interaction between FSH signalling and Notch pathway in Sertoli cells may be involved in spermatogenic activity changes of the testes occurring during puberty or photoperiod shift in continuously and seasonally breeding rodents, respectively.

Nuclear and Membrane Receptors for Sex Steroids Are Involved in the Regulation of Delta/Serrate/LAG-2 Proteins in Rodent Sertoli Cells

Delta/Serrate/LAG-2 (DSL) proteins, which serve as ligands for Notch receptors, mediate direct cell–cell interactions involved in the determination of cell fate and functioning. The present study aimed to explore the role of androgens and estrogens, and their receptors in the regulation of DSL proteins in Sertoli cells. To this end, primary rat Sertoli cells and TM4 Sertoli cell line were treated with either testosterone or 17β-estradiol and antagonists of their receptors. To confirm the role of particular receptors, knockdown experiments were performed. mRNA and protein expressions of Jagged1 (JAG1), Delta-like1 (DLL1), and Delta-like4 (DLL4) were analyzed using RT-qPCR, Western blot, and immunofluorescence. Testosterone caused downregulation of JAG1 and DLL1 expression, acting through membrane androgen receptor ZRT- and Irt-like protein 9 (ZIP9) or nuclear androgen receptor (AR), respectively. DLL4 was stimulated by testosterone in the manner independent of AR and ZIP9 in Sertoli cells. The expression of all studied DSL proteins was upregulated by 17β-estradiol. Estrogen action on JAG1 and DLL1 was mediated chiefly via estrogen receptor α (ERα), while DLL4 was controlled via estrogen receptor β (ERβ) and membrane G-protein-coupled estrogen receptor (GPER). To summarize, the co-operation of nuclear and membrane receptors for sex steroids controls DSL proteins in Sertoli cells, contributing to balanced Notch signaling activity in seminiferous epithelium.

Flutamide treatment reveals a relationship between steroidogenic activity of Leydig cells and ultrastructure of their mitochondria

Our present knowledge on interrelation between morphology/ultrastructure of mitochondria of the Leydig cell and its steroidogenic function is far from satisfactory and needs additional studies. Here, we analyzed the effects of blockade of androgen receptor, triggered by exposure to flutamide, on the expression of steroidogenic proteins (1) and ultrastructure of Leydig cells' constituents (2). We demonstrated that increase in the expression level of steroidogenic (StAR, CYP11A1, 3β-HSD, and CYP19A1) proteins (and respective mRNAs) in rat testicular tissue as well as elevation of intratesticular sex steroid hormone (testosterone and estradiol) levels observed in treated animals correspond well to morphological alterations of the Leydig cell ultrastructure. Most importantly, up-regulation of steroidogenic proteins' expression apparently correlates with considerable multiplication of Leydig cell mitochondria and subsequent formation of local mitochondrial networks. Interestingly, we showed also that the above-mentioned processes were associated with elevated transcription of Drp1 and Mfn2 genes, encoding proteins implicated in mitochondrial dynamics. Collectively, our studies emphasize the importance of mitochondrial homeostasis to the steroidogenic function of Leydig cells.

Nonclassical androgen and estrogen signaling is essential for normal spermatogenesis

Signaling by androgens through androgen receptor (AR) is essential to complete spermatogenesis in the testis. Similarly, loss of the main estrogen receptor, estrogen receptor 1 (ESR1; also known as ERα), results in male infertility, due in part to indirect deleterious effects on the seminiferous epithelium and spermatogenesis. Effects of steroid hormones are induced primarily through genomic changes induced by hormone-mediated activation of their intracellular receptors and subsequent effects on nuclear gene transcription. However, androgens and estrogens also signal through rapid nonclassical pathways involving actions initiated at the cell membrane. Here we review the data that nonclassical androgen and estrogen signaling pathways support processes essential for male fertility in the testis and reproductive tract. The recent development of transgenic mice lacking nonclassical AR or ESR1 signaling but retaining genomic nuclear signaling has provided a powerful tool to elucidate the function of nonclassical signaling in the overall response to androgens and estrogens. Results from these mice have emphasized that nonclassical signaling is essential for full responses to these hormones, and absence of either nonclassical or classical AR or ESR1 pathways produces abnormalities in spermatogenesis and the male reproductive tract. Although additional work is required to fully understand how classical and nonclassical receptor signaling synergize to produce full steroid hormone responses, here we summarize the known physiological functions of the classical and nonclassical androgen and estrogen signaling pathways in the testis and reproductive tract.

Crosstalk between Androgen-ZIP9 Signaling and Notch Pathway in Rodent Sertoli Cells

Our recent study demonstrated altered expression of Notch ligands, receptors, and effector genes in testes of pubertal rats following reduced androgen production or signaling. Herein we aimed to explore the role of nuclear androgen receptor (AR) and membrane androgen receptor (Zrt- and Irt-like protein 9; ZIP9) in the regulation of Notch pathway activation in rodent Sertoli cells. Experiments were performed using TM4 and 15P-1 Sertoli cell lines and rat primary Sertoli cells (PSC). We found that testosterone (10^-8 M-10^-6 M) increased the expression of Notch1 receptor, its active form Notch1 intracellular domain (N1ICD) (p < 0.05, p < 0.01, p < 0.001), and the effector genes Hey1 (p < 0.05, p < 0.01, p < 0.001) and Hes1 (p < 0.05, p < 0.001) in Sertoli cells. Knockdown of AR or ZIP9 as well as antiandrogen exposure experiments revealed that (i) action of androgens via both AR and ZIP9 controls Notch1/N1ICD expression and transcriptional activity of recombination signal binding protein (RBP-J), (ii) AR-dependent signaling regulates Hey1 expression, (iii) ZIP9-dependent pathway regulates Hes1 expression. Our findings indicate a crosstalk between androgen and Notch signaling in Sertoli cells and point to cooperation of classical and non-classical androgen signaling pathways in controlling Sertoli cell function.

Implication of Membrane Androgen Receptor (ZIP9) in Cell Senescence in Regressed Testes of the Bank Vole

Here, we studied the impact of exposure to short daylight conditions on the expression of senescence marker (p16), membrane androgen receptor (ZIP9) and extracellular signal-regulated kinase (ERK 1/2), as well as cyclic AMP (cAMP) and testosterone levels in the testes of mature bank voles. Animals were assigned to groups based on an analysis of testis diameter, weight, seminiferous tubule diameter and the interstitial tissue area: group 1, not fully regressed (the highest parameters); group 2 (medium parameters); or group 3, regressed (the lowest parameters). Cells positive for p16 were observed only in the seminiferous tubule epithelium. However, in groups 1 and 2, these were mostly cells sloughed into the tubule lumen. In group 3, senescent cells resided in between cells of the seminiferous epithelium. Staining for ZIP9 was found in Sertoli cells. Western blot analysis showed a trend towards a decreased expression of p16 and ZIP9 in the testes of the voles in groups 2 and 3, compared to group 1. In addition, a trend towards an increased expression of ERK, as well as an increase of cAMP and testosterone levels, was revealed in group 2. In the regressed testes, a functional link exists between senescence and androgen levels with implication of ZIP9 and cAMP/ERK signaling pathways.

Effects and Mechanisms of Phthalates' Action on Reproductive Processes and Reproductive Health: A Literature Review

The production of plastic products, which requires phthalate plasticizers, has resulted in the problems for human health, especially that of reproductive health. Phthalate exposure can induce reproductive disorders at various regulatory levels. The aim of this review was to compile the evidence concerning the association between phthalates and reproductive diseases, phthalates-induced reproductive disorders, and their possible endocrine and intracellular mechanisms. Phthalates may induce alterations in puberty, the development of testicular dysgenesis syndrome, cancer, and fertility disorders in both males and females. At the hormonal level, phthalates can modify the release of hypothalamic, pituitary, and peripheral hormones. At the intracellular level, phthalates can interfere with nuclear receptors, membrane receptors, intracellular signaling pathways, and modulate gene expression associated with reproduction. To understand and to treat the adverse effects of phthalates on human health, it is essential to expand the current knowledge concerning their mechanism of action in the organism.

Disruption of androgen signaling during puberty affects Notch pathway in rat seminiferous epithelium

BACKGROUND

Onset of spermatogenesis at puberty is critically dependent on the activity of hypothalamic-pituitary-gonadal axis and testosterone production by Leydig cells. The aim of this study was to examine whether activation of Notch receptors and expression of Notch ligands and effector genes in rat seminiferous epithelium are controlled by androgen signaling during puberty.

METHODS

Peripubertal (5-week-old) Wistar rats received injections of flutamide (50 mg/kg bw) daily for 7 days to reduce androgen receptor (AR) signaling or a single injection of ethanedimethane sulphonate (EDS; 75 mg/kg bw) to reduce testosterone production. Gene and protein expressions were analyzed by real-time RT-PCR and western blotting, respectively, protein distribution by immunohistochemistry, and steroid hormone concentrations by enzyme-linked immunosorbent assay. Statistical analyses were performed using one-way ANOVA followed by Tukey's post hoc test or by Kruskal-Wallis test, followed by Dunn's test.

RESULTS

In both experimental models changes of a similar nature in the expression of Notch pathway components were found. Androgen deprivation caused the reduction of mRNA and protein expression of DLL4 ligand, activated forms of Notch1 and Notch2 receptors and HES1 and HEY1 effector genes (p < 0.05, p < 0.01, p < 0.001). In contrast, DLL1, JAG1 and HES5 expressions increased in seminiferous epithelium of both flutamide and EDS-treated rats (p < 0.05, p < 0.01, p < 0.001).

CONCLUSIONS

Androgens and androgen receptor signaling may be considered as factors regulating Notch pathway activity and the expression of Hes and Hey genes in rat seminiferous epithelium during pubertal development. Further studies should focus on functional significance of androgen-Notch signaling cross-talk in the initiation and maintenance of spermatogenesis.