The mechanism of the contribution of ICAM-1 to epithelial-mesenchymal transition (EMT) in bladder cancer

Bladder cancer is one of the most prevalent cancers worldwide. Moreover, if not optimally treated, bladder cancer is a significant burden on healthcare systems due to multiple recurrences which often require more aggressive therapies. Therefore, targeted anti-cancer therapies, developed based on an in-depth understanding of specific proteins and molecular mechanisms, are promising in cancer treatment. Here, for the first time, we presented the new approaches indicating that intracellular adhesion molecule-1 (ICAM-1) may play a potential role in enhancing therapeutic effectiveness for bladder cancer. In the present study, we presented that ICAM-1 expression as well as its regulation in bladder cancer is strongly correlated with the high expression of N-cadherin. Importantly, the presence of N-cadherin and its regulator-TWIST-1 was abolished when ICAM-1 was silenced. We identified also that ICAM-1 is capable of regulating cellular migration, proliferation, and EMT progression in bladder cancer cells via the N-cadherin/SRC/AKT/GSK-3β/β-catenin signaling axis. Therefore, we propose ICAM-1 as a novel metastatic marker for EMT progression, which may also be used as a therapeutic target in bladder cancer.

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.

The uterusmasculinus of the Eurasian beaver (Castor fever L.) - The appraisal of fast hormone regulation by membrane androgen and estrogen receptors involvement

The phenomenon of remaining paramesonephric ducts (uterus masculinus) in males of some animal species concerning its role is still an unresolved issue. Now it is well-recognized that sex hormonal regulation of reproductive physiology involves also fast nongenomic control of cellular processes through noncanonical signaling. Herein, in the uterus masculinus of Eurasian beaver membrane androgen receptor (metal ion transporter Zrt- and Irt-like protein 9; ZIP9) and membrane estrogen receptor (G protein-coupled estrogen receptor; GPER) were studied. Scanning electron microscopy together with anatomical analysis revealed that Eurasian male beavers possess one double uterus (uterus duplex). Two odd parts open into the vagina but do not form a common lumen. The length of the horns is the most differential feature of this organ in studied animals. Uterus masculinus is not a tightly closed tubular structure. Histological analysis showed an analogy to the female uterus structure however no glands but gland-like structures were observed. The presence and abundant localization of ZIP9 and GPER proteins in cells of uterus masculinus was confirmed by immunohistochemistry while their expression was measured by western blotting. GPER expression in remnants was lower (P < 0.001) than those in the female uterus. Parallelly, the concentration of progesterone and estradiol but not testosterone was lower (P < 0.05 and P < 0.01, respectively) in comparison to the female uterus. Our study, for the first time, reports the involvement of fast hormonal regulation in the uterus masculinus of Eurasian beavers reflecting the participation of this organ in the creation local hormonal environment. Moreover, the uterus masculinus seems to be a useful research model for understanding and resolving urgent biological problems such as gender identities and having children by women with a lack of uterus or anatomical barriers on this level.

Effect of indoxyl sulfate on the morphology and function of the thyroid gland - ex vivo studies in rabbits

Indoxyl sulfates are uremic indolic toxins known to participate in the pathogenesis of cardiovascular diseases during chronic kidney disease in humans and some animal species. However, nothing is known about the indoxyl sulfate effect on the thyroid gland which is especially responsible for the general organism metabolism. This study determines the morpho-functional status of the thyroid gland after exposure to indoxyl sulfate (10, 25, and 50 mM) with the use of an ex vivo system and rabbit (n=10) as an experimental model thyroid gland histology, immunoexpression of thyrotropin receptor (TSHR), and concentrations of thyroxine (T4) and triiodothyronine (T3) were evaluated. Statistical analyses were performed using one-way analysis of the variance (ANOVA) followed by Tukey's post hoc comparison test. Minor alterations in thyroid tissue structure e.g. very rare exfoliated epithelial cells, condensed colloid fluid, or slight loosening of the epithelium were found. In addition, modulated dose dependent-expression of TSHR (p<0.01, p<0.001) together with a decreased level of T4 and T3 (p<0.001, p<0.01) exception of an increased level of T4 after the middle dose of indoxyl sulfate were revealed. We report here, for the first time, that indoxyl sulfate affects the thyroid gland mainly at the molecular level. The rabbit thyroid gland ex vivo system seems to be suitable for further studies on the thyroid gland in health and disease. However, the effect of TSH-TSHR signaling at ultrastructural, and epigenetic levels needs supplementary appraisal.

Spexin role in human granulosa cells physiology and PCOS: expression and negative impact on steroidogenesis and proliferation†

Spexin (SPX) is a novel neuropeptide and adipokine negatively correlated with obesity and insulin resistance. A recent study investigated expression and regulatory function of SPX in the hypothalamus and pituitary; however, the effect on ovarian function is still unknown. The aim of this study was to characterize the expression of SPX and its receptors, galanin receptors 2 and 3 (GALR2/3), in the human ovary and to study its in vitro effect on granulosa cells (GC) function. Follicular fluid (FF) and GC were obtained from normal weight and obese healthy and diagnosed with polycystic ovarian syndrome (PCOS) women. Expression of SPX and GALR2/3 in the ovary was studied by qPCR, western blot, and immunohistochemistry. The level of SPX in FF was assessed by enzyme-linked immunosorbent assay. The in vitro effect of recombinant human SPX on GC proliferation, steroidogenesis, and signaling pathways (MAP3/1, STAT3, AKT, PKA) was analyzed. Moreover, GC proliferation and estradiol (E2) secretion were measured with and without an siRNA against GALR2/3 and pharmacological inhibition of the above kinases. The results showed that both the SPX concentration in FF and its gene expression were decreased in GC of obese and PCOS women, while the protein expression of GALR2/3 was increased. We noted that SPX reduced GC proliferation and steroidogenesis; these effects were mediated by GALR2/3 and kinases MAP3/1, AKT, and STAT3 for proliferation or kinases MAP3/1 and PKA for E2 secretion. The obtained data clearly documented that SPX is a novel regulator of human ovarian physiology and possibly plays a role in PCOS pathogenesis.

Status of estrogen receptor expression and epigenetic methylation in Leydig cells after exposure to metalloestrogen - selenium

The trace element selenium (Se) is essential for the maintenance of spermatogenesis and fertility. A growing volume of evidence shows that Se is necessary for testosterone synthesis, and Se can stimulate Leydig cell proliferation. However, Se can also act as a metalloestrogen, which can mimic estrogen and activate the estrogen receptors. This study aimed to investigate Se effect on estrogen signaling and the epigenetic status of Leydig cells. Mouse Leydig cells (MA-10) were cultured in a medium supplemented with different Se concentrations (4, 8µM) for 24hours. Next, cells were assessed for morphological and molecular (qRT PCR, western blot, immunofluorescence) analyses. Immunofluorescence revealed strong immunosignal for 5-methylcytosine in both control and treated cells, with a stronger signal in the 8μM treated group. qRT-PCR confirmed an increased expression of methyltransferase 3β (Dnmt3b) in 8μM cells. Analysis of the expression of γH2AX (a marker for double-stranded DNA breaks) revealed an increase in the DNA breaks in cells exposed to 8μM Se. Selenium exposure did not affect the expression of canonical estrogen receptors (ERα and ERβ), however, an increase in membrane estrogen receptor G-protein coupled (GPER) protein expression was observed. To sum up, in a high concentration (8μM) Se affects GPER expression (non-genomic estrogen signaling) in Leydig cells possibly via acting on receptor protein and/or its binding. This causes DNA breaks and induces changes in Leydig cell methylation status, especially in de novo methylation which is mediated by Dnmt3b.

Next-Generation Sequencing analysis discloses genes implicated in equine endometrosis that may lead to tumorigenesis

Endometrosis is a periglandular fibrosis associated with dysfunction of affected glandular epithelial cells that is the most common cause of reduced fertility in mares, although it is not fully understood. The etiology of the disease is still partially unknown. This study focuses on understanding the genetic mechanisms potentially underlying endometrosis in mares using the Next Generation Sequencing (NGS) technique. Endometrial samples, used in the study, were obtained in the anestrus phase both from healthy mares and those diagnosed with endometrosis. The NGS data were analyzed for gene involvement in biological processes and pathways (e.g. STAR, KOBAS-I, STRING, and ClustVis software). Bioinformatic analysis revealed differential expression of 55 transcripts. In tissues with endometrosis, most genes displayed upregulated expression. The protein-protein interaction analysis disclosed a substantial transcript network including transcripts related to metabolism e.g. sulfur metabolism (SELENBP1), ovarian steroidogenesis, steroid hormone biosynthesis, and chemical carcinogenesis (CYP1B1), COXs (COX4I1, COX3, UQCRFS1) as well as transcripts related to immune response e.g. MMP7, JCHAIN, PIGR, CALR, B2M, FCGRT. Interestingly, the latter has been previously linked with various pathologies including cancers in the female reproductive system. In conclusion, this study evaluated genes that are not directly impacted by sex hormone feedback, but that create a metabolic and immune environment in tissues, thus influencing fertility and pregnancy in mares with endometrosis. Moreover, some of the identified genes may be implicated in tumorigenesis of endometrial lesions. These data may be useful as a starting point in further research, such as the development of targeted strategies for rapid diagnosis and/or prevention of this pathology based on gene and protein-protein interactions.

Another lesson from unmapped reads: in-depth analysis of RNA-Seq reads from various horse tissues

In recent years, a vast amount of sequencing data has been generated and large improvements have been made to reference genome sequences. Despite these advances, significant portions of reads still do not map to reference genomes and these reads have been considered as junk or artificial sequences. Recent studies have shown that these reads can be useful, e.g., for refining reference genomes or detecting contaminating microorganisms present in the analyzed biological samples. A special case of this is RNA sequencing (RNA-Seq) reads that come from tissue transcriptomes. Unmapped reads from RNA-Seq have received much less attention than those from whole-genome sequencing. In particular, in the horse, an analysis of unmapped RNA reads has not been performed yet. Thus, in this study, we analyzed the unmapped reads originating from the RNA-Seq performed through the Functional Annotation of Animal Genomes (FAANG) project in the horse, using eight different tissues from two mares. We demonstrated that unmapped reads from RNA-Seq could be easily assembled into transcripts relating to many important genes present in the sequences of other mammals. Large portions of these transcripts did not have coding potential and, thus, can be considered as non-coding RNA. Moreover, reads that were not mapped to the reference genome but aligned to the entries in NCBI database of horse proteins were enriched for biological processes that largely correspond to the functions of organ from which RNA was isolated and thus are presumably true transcripts of genes associated with cell metabolism in those tissues. In addition, a portion of reads aligned to the common pathogenic or neutral microbiota, of which the most common was Brucella spp. These data suggest that unmapped reads can be an important target for in-depth analysis that may substantially enrich results of initial RNA-Seq experiments for various tissues and organs.

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.

Status of prooxidant and antioxidant systems in the sperm and seminal plasma of breeding boars of large white breed and SS23 synthetic line

The indicators of pro- and antioxidant systems in sperm and sperm plasma of breeding boars of Large White breed and SS23 synthetic line were studied. Measurements of antioxidant enzyme activity, determination of lipid peroxidation (LPO) product content, and antioxidant factor were performed. Lipid peroxidation in the semen of healthy breeding boars was characterized by a stable level of activity, which is necessary to ensure normal reproductive functions. Additionally, there was a high content of low molecular weight thiols and proteins. The concentration of SH-groups in spermatozoa was higher (P≤0.05) compared to sperm plasma. The number of total, protein, and free SH-groups in the semen of boars of the synthetic line was higher (P<0.05) in relation to animals of the Large White breed. Low catalase (CAT) activity in the sperm was compensated by glutathione peroxidase (GPX). The content of ceruloplasmin (CP) in the sperm of boars was almost twice as high as that of sperm plasma. In spermatozoa, high content of reduced glutathione (GTH) was recorded, which was more than 3 times higher than in the seminal fluid. The main antioxidants of spermatozoa were superoxide dismutase (SOD), CP, SH-groups of proteins, and reduced content of GTH. We revealed that CAT is a key enzyme that neutralizes excess hydrogen peroxide in boar semen. In contrast, in sperm, hydrogen peroxide was inactivated mainly by GPX. Further research on the mechanisms of action of reactive oxygen species on boar semen will help to develop effective methods for sperm storage and successful fertilization of oocytes.

Apelin, APJ, and ELABELA: Role in Placental Function, Pregnancy, and Foetal Development-An Overview

The apelinergic system, which includes the apelin receptor (APJ) as well as its two specific ligands, namely apelin and ELABELA (ELA/APELA/Toddler), have been the subject of many recent studies due to their pleiotropic effects in humans and other animals. Expression of these factors has been investigated in numerous tissues and organs—for example, the lungs, heart, uterus, and ovary. Moreover, a number of studies have been devoted to understanding the role of apelin and the entire apelinergic system in the most important processes in the body, starting from early stages of human life with regulation of placental function and the proper course of pregnancy. Disturbances in the balance of placental processes such as proliferation, apoptosis, angiogenesis, or hormone secretion may lead to specific pregnancy pathologies; therefore, there is a great need to search for substances that would help in their early diagnosis or treatment. A number of studies have indicated that compounds of the apelinergic system could serve this purpose. Hence, in this review, we summarized the most important reports about the role of apelin and the entire apelinergic system in the regulation of placental physiology and pregnancy.

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.

Towards understanding leydigioma: do G protein-coupled estrogen receptor and peroxisome proliferator-activated receptor regulate lipid metabolism and steroidogenesis in Leydig cell tumors?

Leydig cell tumors (LCT) are the most common type of testicular stromal tumor. Herein, we investigate the G protein-coupled estrogen receptor (GPER) and peroxisome proliferator-activated receptor (PPAR) implication in regulation of lipid homeostasis including the expression of steroidogenesis-controlling molecules in clinical specimens of LCTs and tumor Leydig cells (MA-10). We showed the general structure and morphology of LCTs by scanning electron and light microscopy. In LCTs, mRNA and protein analyses revealed increased expression of GPER and decreased expression of PPARα, β, and γ. Concomitantly, changes in expression pattern of the lutropin receptor (LHR), protein kinase A (PKA), perilipin (PLIN), hormone sensitive lipase (HSL), steroidogenic acute regulatory protein (StAR), translocator protein (TSPO), HMG-CoA synthase, and reductase (HMGCS, HMGCR) were observed. Using MA-10 cells treated with GPER and PPAR antagonists (alone and in combination), we demonstrated GPER-PPAR-mediated control of estradiol secretion via GPER-PPARα and cyclic guanosine monophosphate (cGMP) concentration via GPER-PPARγ. It is assumed that GPER and PPAR can crosstalk, and this can be altered in LCT, resulting in a perturbed lipid balance and steroidogenesis. In LCTs, the phosphatidylinositol-3-kinase (PI3K)-Akt-mTOR pathway was disturbed. Thus, PI3K-Akt-mTOR with cGMP can play a role in LCT outcome and biology including lipid metabolism.

Mouse testicular transcriptome after modulation of non-canonical oestrogen receptor activity

The aims of this study were to shed light on the role of G-protein-coupled membrane oestrogen receptor (GPER) and oestrogen-related receptor (ERR) in mouse testis function at the gene expression level, as well as the involvement of GPER and ERR in cellular and molecular processes. Male mice were injected (50µg kg-1,s.c.) with the GPER antagonist G-15, the ERRα inverse agonist XCT790 or the ERRβ/ERRγ agonist DY131. Next-generation sequencing (RNA-Seq) was used to evaluate gene expression. Bioinformatic analysis of read abundance revealed that 50, 86 and 171 transcripts were differentially expressed in the G-15-, XCT790- and DY131-treated groups respectively compared with the control group. Annotated genes and their protein products were categorised regarding their associated biological processes and molecular functions. In the XCT790-treated group, genes involved in immunological processes were upregulated. In the DY131-treated group, genes with increased expression were primarily engaged in protein modification (protein folding and small protein conjugation). In addition, the expression of genes recognised as oncogenes, such as BMI1 proto-oncogene, polycomb ring finger (Bmi1) and nucleophosphin 1 (Npm1), was significantly increased in all experimental groups. This study provides detailed information regarding the genetic changes in the testicular transcriptome of the mouse in response to modulation of non-canonical oestrogen receptor activity.

The meaning of non-classical estrogen receptors and peroxisome proliferator-activated receptor for boar Leydig cell of immature testis

Communication in biological systems involves diverse-types of cell-cell interaction including cross-talk between receptors expressed by the target cells. Recently, novel sort of estrogen receptors (G protein - coupled estrogen receptor; GPER and estrogen-related receptor; ERR) that signal directly via estrogen binding and/or via mutual interaction-regulated estrogen signaling were reported in various organs including testis. Peroxisome proliferator - activated receptor (PPAR) is responsible for maintaining of lipid homeostasis that is critical for sex steroid production in the testis. Here, we investigated the role of interaction between GPER, ERRβ and PPARγ in steroidogenic Leydig cells of immature boar testis. Testicular fragments cultured ex vivo were treated with GPER or PPARγ antagonists. Then, cell ultrastructure, expression and localization of GPER, ERRβ, PPARγ together with the molecular receptor mechanism, through cyclic AMP and Raf/Ras/extracellular signal activated kinases (ERK), in the control of cholesterol concentration and estrogen production by Leydig cells were studied. In the ultrastructure of antagonist-treated Leydig cells, mitochondria were not branched and not bifurcated as they were found in control. Additionally, in PPARγ-blocked Leydig cells changes in the number of lipid droplets were revealed. Independent of used antagonist, western blot revealed decreased co-expression of GPER, ERRβ, PPARγ with exception of increased expression of ERRβ after PPARγ blockage. Immunohistochemistry confirmed presence of all receptors partially located in the nucleus or cytoplasm of Leydig cells of both control and treated testes. Changes in receptor expression, decreased cholesterol and increased estradiol tissue concentrations occurred through decreased cAMP level (with exception after GPER blockage) as well as Raf/Ras/ERK pathway expression. These all findings indicate that GPER-ERRβ-PPARγ interaction exists in immature boar testis and regulates Leydig cell function. Further detailed studies and considerations on GPER-ERRβ-PPARγ as possible diagnosis/therapy target in disturbances of testis steroidogenic function are needed.

Apelin and apelin receptor in human placenta: Expression, signalling pathway and regulation of trophoblast JEG‑3 and BeWo cells proliferation and cell cycle

Placentation requires the production of numerous growth factors, hormones and transcription factors. Many of them, like the adipose tissue-derived leptin or adiponectin, have been identified in the placenta and their role has been established in the proliferation and subsequent development of the placenta. Apelin is another adipokine known for proliferative effects in different cell types. PCR, immunoblotting and immunocytochemistry were used to study mRNA and protein expression of apelin and its receptor (APJ) in syncytiotrophoblast (BeWo) and cytotrophoblast (JEG-3) cells as well in immunohistochemistry in human normal placenta slides. The effect of apelin on cell proliferation study was investigated by alamarBlue^® and Cell Counting Kit-8 assays, the cell cycle by the flow cytometry method and the protein expression of cyclins and phosphorylation level of extracellular signal-regulated kinases (ERK)1/2, phosphatidylinositol 3′-kinase/protein kinase B (Akt), signal transducer and activator of transcription 3 (Stat3) and 5′-monophosphate-activated protein kinase (AMPKα) were studied by western blotting. Apelin was increased in JEG-3 compared with in BeWo cells, while APJ was the same in both placenta cell lines. Immunocytochemical analyses revealed high cytoplasmic and/or membrane apelin localisation in JEG-3, while BeWo cells exhibited markedly weaker apelin signal in the cytoplasm. Apelin increased cell proliferation as well as the percentage of cells in the G2/M phase of the cell cycle, cyclin proteins and the expression of all kinases mentioned above. In conclusion, apelin by promotion of trophoblast cell proliferation by APJ and ERK1/2, Stat3 and AMPKα signalling could be a new important adipokine in the regulation of early placental development.

Differential expression of cell-cell junction proteins in the testis, epididymis, and ductus deferens of domestic turkeys (Meleagris gallopavo) with white and yellow semen

Tight, adherens, and gap junctions are involved in the regulation of reproductive tissue function in male mammals. In birds, including domestic turkeys, intercellular interactions performed by junctional networks have not yet been studied. Furthermore, the cellular and molecular basis of yellow semen syndrome (YSS) in the turkey population remains poorly understood. Thus, the aim of the present study was 2-fold: first, to provide new information on the localization and expression of cell-cell junction proteins in the testis, epididymis, and ductus deferens of domestic turkeys and second, to compare expression of junctional protein genes between 2 turkey population, one that produces white normal semen (WNS) and the other that produces yellow abnormal semen. Expression of occludin, zonula occludens-1 (ZO-1), connexin 43 (Cx43), N- and E-cadherin, and β-catenin genes were investigated using 3 complementary techniques: quantitative real-time PCR, western blot, and immunohistochemistry. Compared to WNS testis, epididymis, and ductus deferens, YSS tissues exhibited downregulation of occludin and β-catenin mRNA (P < 0.05) and protein (P < 0.05 and P < 0.01, respectively) and upregulation of N- and E-cadherin mRNA (P < 0.001, P < 0.05, P < 0.01, respectively) and protein (P < 0.01, P < 0.05, and P < 0.05, respectively). In contrast, ZO-1 and Cx43 mRNA and protein were upregulated in YSS testis (P < 0.05 and P < 0.001, respectively) but not in epididymis and ductus deferens; both mRNAs and proteins were downregulated (P < 0.05) compared to the respective WNS epididymis and ductus deferens. Altered staining intensity of immunoreactive proteins in YSS vs. WNS reproductive tissue sections confirmed the gene expression results. The present study is the first to demonstrate altered levels of junctional protein gene expression in reproductive tissues of male YSS turkeys. These findings may suggest that subtle changes in junctional protein expression affect the microenvironment in which spermatozoa develop and mature and thus may have an impact on the appearance of yellow semen in domestic turkeys.

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

BACKGROUND

Notch signaling pathway is involved in contact-dependent communication between the cells of seminiferous epithelium, and its proper activity is important for undisturbed spermatogenesis.

OBJECTIVES

The aim was to assess the effect of Notch pathway inhibition on the expression of nuclear (AR) and membrane (ZIP9) androgen receptors and androgen-regulated genes, claudin-5 and claudin-11, in TM4 mouse Sertoli cell line.

MATERIALS AND METHODS

DAPT (γ-secretase inhibitor) treatment and recombination signal binding protein silencing were employed to reduce Notch signaling, whereas immobilized ligands were used to activate Notch pathway in TM4 cells. To reveal specific effect of each androgen receptor, AR or ZIP9 silencing was performed.

RESULTS

Notch pathway inhibition increased the expression of AR and ZIP9 mRNA and proteins (p < 0.01; p < 0.05) in TM4 cells, whereas incubation with Notch ligands, rDLL1 or rJAG1, reduced AR (p < 0.01; p < 0.001) and ZIP9 (p < 0.05; p < 0.01) expressions, respectively. Testosterone enhanced the expression of both receptors (p < 0.05; p < 0.01). Androgen-regulated claudin-5 and claudin-11 (p < 0.01; p < 0.001) and cAMP (p < 0.001) were elevated in Notch-inhibited cells, while activation of Notch signaling by DLL1 or JAG1 reduced claudin-11 or claudin-5 level (p < 0.01; p < 0.001), respectively.

DISCUSSION

Our findings indicate opposite effect of Notch and androgen signaling on the expression of androgen receptors in TM4 cells. We demonstrated that AR expression is regulated by DLL1-mediated Notch signaling, whereas JAG1 is involved in the regulation of ZIP9. The expression of both claudins and cAMP production is under inhibitory influence of Notch pathway. The effects of Notch signaling on claudin-5 and claudin-11 expression are mediated by ZIP9 and AR, respectively.

CONCLUSION

Notch signaling may be considered as an important pathway controlling Sertoli cell physiology, and its alterations may contribute to disturbed response of Sertoli cells to androgens.

Leydig cell tumorigenesis - implication of G-protein coupled membrane estrogen receptor, peroxisome proliferator-activated receptor and xenoestrogen exposure. In vivo and in vitro appraisal

The etiology and molecular characteristics of Leydig cell tumor (LCT) are scarcely known. From the research data stems that estrogen can be implicated in LCT induction and development, however it is not investigated in detail. Considering the above, herein we analyzed the relation between G-protein coupled membrane estrogen receptor, peroxisome proliferator-activated receptor and insulin-like family peptides (insulin-like 3 peptide; INSL3 and relaxin; RLN) expressions as well as estrogen level with impact of xenoestrogen (bisphenol A; BPA, tetrabromobisphenol A; TBBPA, and tetrachlorobisphenol A; TCBPA). While in our previous studies altered GPER-PPAR partnership was found in human LCT being a possible cause and/or additionally effecting on LCT development, here mouse testes with experimentally induced LCT and mouse tumor Leydig cell (MA-10) treated with BPA chemicals were examined. We revealed either diverse changes in expression or co-expression of GPER and PPAR in mouse LCT as well as in MA-10 cells after BPA analogues when compared to human LCT. Relationships between expression of INSL3, RLN, including co-expression, and estrogen level in human LCT, mouse LCT and MA-10 cells xenoestrogen-treated were found. Moreover, involvement of PI3K-Akt-mTOR pathway or only mTOR in the interactions of examined receptors and hormones was showed. Taken together, species, cell of origin, experimental system used and type of used chemical differences may result in diverse molecular characteristics of LCT. Estrogen/xenoestrogen may play a role in tumor Leydig cell proliferation and biochemical nature but this issue requires further studies. Experimentally-induced LCT in mouse testis and MA-10 cells after BPA exposure seem to be additional models for understanding some aspects of human LCT biology.

Do estrogens regulate lipid status in testicular steroidogenic Leydig cell?

In this study mouse Leydig cell (MA-10) were treated with G-protein coupled membrane estrogen receptor antagonist (G-15; 10 nM). Cells were analyzed by Western blotting for expression of estrogen-related receptors (ERRα, β and γ), steroidogenic markers (lutropin receptor; LHR and 3β-hydroxysteroid dehydrogenase; 3β-HSD) and lipid droplet markers (perilipin; PLIN and microtubule-associated protein 1 A/1B-light chain 3; LC3). Concomitantly, microscopic analyses by light microscope (immunofluorescent staining for lipid droplets, PLIN and LC3) as well as by electron microscope (for lipid droplet ultrastructure) were utilized. For analysis of cholesterol content, cAMP level and progesterone secretion, G-15, estrogen receptor (ER) antagonist (ICI 182,780; 10 μM), 17β-estradiol (10 mM) and, bisphenol A (BPA; 10 nM) were used alone or in combinations. We revealed no changes in ERRs expression but alterations in ERRβ and γ localization in G-15-treated cells when compared to control. Partial translocation of ERRβ and γ from the cell nucleus to cytoplasm was observed. Decreased expression of LHR, 3β-HSD, PLIN and LC3 was detected. Moreover, in treated cells large lipid droplets and differences in their distribution were found. Very strong signal of co-localization for PLIN and LC3 was found in treated cells when compared to control. In ultrastructure of treated cells, degenerating lipid droplets and double membrane indicating on presence of lipophagosome were observed. We found, that only (i) BPA and G-15 did not effect on cholesterol content, (ii) BPA, G-15 and ICI did not effect on cAMP level and (iii) BPA, ICI alone and in combination, and BPA with G-15 did not modulate progesterone secretion. These findings showed complex and diverse estrogen effects on mouse Leydig cells at various steps of steroid hormone production (cholesterol storage, release and processing). Lipid homeostasis and metabolism in these cells were affected by endogenous and exogenous estrogen, interactions of receptors (GPER, ER and ERR) and GPER and ER antagonists.

Do G-protein coupled estrogen receptor and bisphenol A analogs influence on Leydig cell epigenetic regulation in immature boar testis ex vivo?

Organotypic culture of testicular fragments from 7-day-old male pigs (Polish White Large) was used. Tissues were treated with an antagonist of G-protein coupled estrogen receptor (GPER) (G-15; 10 nM), and bisphenol A (BPA), and its analogs (TBBPA, TCBPA; 10 nM) alone or in combination and analyzed using electron and light (stainings for collagen fibers, lipid droplet and autophagy markers) microscopes. In addition, mRNA and protein abundances and localization of molecules required for miRNA biogenesis and function (Drosha, Exportin 5; EXPO5, Dicer, and Argonaute 2; AGO2) were assessed together with calcium ion (Ca²⁺) and estradiol concentrations. Regardless of GPER blockade and/or treatment with BPA, TBBPA and TCBPA, there were no changes in Leydig cell morphology. Also, there were no changes in lipid droplet content and distribution but there were changes in lipid and autophagy protein abundance. In the interstitial tissue, there was an increase of collagen content, especially after treatment with BPA analogs and G-15 + BPA. Independent of the treatment, there was downregulation of EXPO5 and Dicer genes but the Drosha and AGO2 genes were markedly upregulated as a result of treatment with G-15 + BPA and TCBPA, respectively. There was always a lesser abundance of EXPO5 and AGO2 proteins regardless of treatment. There was markedly greater abundances of Drosha after G-15 + BPA treatment, and this also occurred for Dicer after treatment with G-15 + TCBPA. Immunolocalization of miRNA proteins indicated there was a cytoplasmic-nuclear pattern in control and treated cells. There was an increase of Ca²⁺ concentrations after treatment with G-15 and BPA analogs. Estradiol secretion decreased after antagonist and chemical treatments when these were administered alone, however, there was an increase in estradiol secretion after treatment with combinations of these compounds.

Regulation of steroidogenic function of mouse Leydig cells: G-coupled membrane estrogen receptor and peroxisome proliferator-activated receptor partnership

We tested whether G-coupled membrane estrogen receptor (GPER) and peroxisome proliferator activated receptor (PPAR) partnership exists and whether this interaction regulates mouse Leydig cell function. Mature and aged mice were treated with the antagonist of GPER (G-15; 50 μg/kg b.w). Leydig cells (MA-10) were treated with G-15 (10 nM) alone or in combination with peroxisome proliferator-activated receptor α or γ antagonists, respectively (PPARα, 10 μM; PPARγ, 10 μM). GPER blockage affected testis steroidogenic status via changes in lutropin and cholesterol levels as well as protein expression alterations of the lutropin receptor, acute steroidogenesis activating protein, translocator protein, and protein kinase A in mouse Leydig cells both in vivo and in vitro. Inactivation of both GPER and PPAR in vitro revealed expressional modulation of other steroidogenesis-controlling molecules acting on various steps of lipid homeostasis e.g. cytochrome P450scc, perilipin, hormone sensitive lipase, and 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase. Concomitantly, microscopic analysis of cells treated with antagonists showed changes in morphology, migration competences and cytoskeleton structure. In the above processes, the action of GPER and PPARα was regulated through the PI3K/Akt pathway, while PPARγ was mediated by the Ras/Raf pathway. In addition, GPER and PPARs specifically controlled individual signaling proteins. For the first time, we report here the importance of GPER-PPARα and -PPARγ 'neopartnership' in maintenance of Leydig cell morpho-functional status.

Differences in aromatase expression and steroid hormone concentrations in the reproductive tissues of male domestic turkeys (Meleagris gallopavo) with white and yellow semen

1. To show hormonal differences between male turkeys with yellow semen syndrome (YSS) and white, normal semen (WNS), the expression of aromatase, oestrogen receptor α (ERα), and oestrogen receptor β (ERβ) as well as testosterone and oestradiol concentrations in YSS and WNS testes, epididymis, and ductus deferens were examined. 2. To measure gene expression levels of aromatase and oestrogen receptors (ERs), three complementary techniques (real-time PCR, Western blot, and immunohistochemistry) were used, whereas steroid hormone levels were determined radio-immunologically. 3. Upregulation of aromatase and ERα mRNAs in YSS testes (P < 0.05; P < 0.01), epididymis (P < 0.001; P < 0.001), and ductus deferens (P < 0.05; P < 0.01) compared to those of WNS tissues was detected. Significant increases in the levels of aromatase and ERα proteins were detected in YSS testes (P < 0.001; P < 0.05), epididymis (P < 0.001; P < 0.001), and ductus deferens (P < 0.001; P < 0.05). The expression of ERβ mRNA and protein level was upregulated in the testes (P < 0.05; P < 0.01) and epididymis (P < 0.001; P < 0.01) but not in ductus deferens where it was downregulated (P < 0.01; P < 0.01). Increased intensity of immunoreactive proteins in YSS versus WNS reproductive tissues corroborated gene expression results. 4. Testosterone concentration diminished in YSS epididymis (P < 0.05) and ductus deferens (P < 0.05), but not in the testes, remaining at high level (P < 0.05) compared to WNS values. Concomitantly, increased oestradiol concentration was found in YSS testes (P < 0.05) and epididymis (P < 0.05) but decreased in the ductus deferens (P < 0.05). 5. From the published literature, this study is the first to demonstrate the ability for androgen aromatisation in the turkey reproductive tissues and to show the cellular targets for locally produced oestrogens. The data suggested that the androgen/oestrogen ratio is a mechanistic basis for amplification of differences between turkeys with white and yellow semen and that these results can have a relevance in applied sciences to widen the knowledge on domestic bird reproduction.

Interplay between estrogen-related receptors and steroidogenesis-controlling molecules in adrenals. In vivo and in vitro study

Estrogen-related receptors (ERRs) α, β and γ appear to be novel molecules implicated in estrogen signaling. We blocked and activated ERRs in mouse (C57BL/6) adrenals and adrenocortical cells (H295R) using pharmacological agents XCT 790 (ERRα antagonist) and DY131 (ERRβ/γ agonist), respectively. Mice were injected with XCT 790 or DY131 (5 μg/kg bw) while cells were exposed to XCT 790 or DY131 (0.5 μg/L). Irrespectively of the agent used, changes in adrenocortical cell morphology along with changes in lutropin, cholesterol levels and estrogen production were found. Diverse and complex ERRs regulation of multilevel-acting steroidogenic proteins (perilipin; PLIN, cytochrome P450 side-chain cleavage; P450scc, translocator protein; TSPO, steroidogenic acute regulatory protein; StAR, hormone sensitive lipase; HSL and HMG-CoA reductase; HMGCR) was revealed. Blockage of ERRα decreased P450scc, StAR and TSPO expressions. Activation of ERRβ/γ increased P450scc, StAR and HMGCR while decreased HSL expressions. PLIN expression increased either after XCT 790 or DY131 treatment. Additionally, treatment with both XCT 790 or DY131 decreased activity of Ras/Raf, Erk and Akt indicating their involvement in control of morphology and steroidogenic function of cortex cells. ERRs are important in maintaining morpho-function of cortex cells through action in specific, opposite, or common manner on steroidogenic molecules.

The role of G-protein-coupled membrane estrogen receptor in mouse Leydig cell function-in vivo and in vitro evaluation

In this study, G-coupled estrogen receptor (GPER) was inactivated, by treatment with antagonist (G-15), in testes of C57BL/6 mice: immature (3 weeks old), mature (3 months old) and aged (1.5 years old) (50 μg/kg bw), as well as MA-10 mouse Leydig cells (10 nM/24 h) alone or in combination with 17β-estradiol or antiestrogen (ICI 182,780). In G-15-treated mice, overgrowth of interstitial tissue was found in both mature and aged testes. Depending on age, differences in structure and distribution of various Leydig cell organelles were observed. Concomitantly, modulation of activity of the mitochondria and tubulin microfibers was revealed. Diverse and complex GPER regulation at the mRNA level and protein of estrogen signaling molecules (estrogen receptor α and β; ERα, ERβ and cytochrome P450 aromatase; P450arom) in G-15 Leydig cells was found in relation to age and the experimental system utilized (in vivo and in vitro). Changes in expression patterns of ERs and P450arom, as well as steroid secretion, reflected Leydig cell heterogeneity to estrogen regulation throughout male life including cell physiological status.We show, for the first time, GPER with ERs and P450arom work in tandem to maintain Leydig cell architecture and supervise its steroidogenic function by estrogen during male life. Full set of estrogen signaling molecules, with involvement of GPER, is crucial for proper Leydig cell function where each molecule acts in a specific and/or complementary manner. Further understanding of the mechanisms by which GPER controls Leydig cells with special regard to male age, cell of origin and experimental system used is critical for predicting and preventing testis steroidogenic disorders based on perturbations in estrogen signaling.

Bisphenol A and dibutyl phthalate affect the expression of juxtacrine signaling factors in rat testis

The study was designed to examine the effects of model plastic derived compounds, bisphenol A (BPA) and dibutyl phthalate (DBP), on juxtacrine communication in adult rat testis, by evaluating the expression of Notch pathway components. Testicular explant were exposed in vitro to BPA (5 × 10^-6 M, 2.5 × 10^-5 M, 5 × 10^-5 M) or DBP (10^-6 M, 10^-5 M, 10^-4 M) for 24 h. To determine the expression of Notch1, Dll4, Hey1, Hes1 and Hey5 real-time RT-PCR was used. Protein levels and localization of NOTCH1 receptor, its ligand DLL4 as well as HEY1, HES1 and HEY5 factors were detected by western blot analysis and immunohistochemistry, respectively. Upregulation of Notch1, Dll4 and Hey1 at the mRNA and protein level was demonstrated in testis explants after BPA and DBP treatment (p < 0.05; p < 0.01; p < 0.001). Hes5 expression decreased after BPA (p < 0.05; p < 0.01; p < 0.001), whereas Hes1 expression was not altered by either BPA or DBP. Tested chemicals altered immunoexpression of activated NOTCH1, DLL4, HEY1 and HES5 both in seminiferous epithelium and interstitial tissue, exerting differential effects on particular cell types. In conclusion, BPA and DBP affect Notch signaling pathway in rat testis, which indicates that juxtacrine communication is a potential target for the action of plastic derived compounds in male gonad.

Apelin and apelin receptor at different stages of corpus luteum development and effect of apelin on progesterone secretion and 3β-hydroxysteroid dehydrogenase (3β-HSD) in pigs

Recent studies have suggested that apelin has a role in controlling female reproduction. The aims of the present study were, firstly, to investigate the gene expression (mRNA and protein) and immunolocalization of apelin and its receptor APJ in corpora lutea (CL) of pigs collected during the early (CL1), middle (CL2) and late (CL3) luteal phase. Using real time PCR and immunoblotting techniques, it was observed that apelin gene expression was similar in CL1 and CL2, and less in CL3, while relative abundance APJ mRNA and abundance of the protein were similar in CL1 and CL3 and greater in CL2. There was apelin staining in the cytoplasm of both small (SC) and large (LC) luteal cells with the greatest intensity in CL2. In the cytoplasm of CL1, only a few SC cells stained for APJ; in CL2, APJ was located in the cell membrane of LC and in the cytoplasm of SC; and in CL3 was located in the membrane with moderate cytoplasmic APJ staining. Intense APJ staining was noted in epithelium of blood vessels of CL2-3. Secondly, there was an effect of apelin on progesterone (P4) secretion in CL2 and on the molecular mechanisms of these cells. Stimulatory effects of apelin on P4 secretion, 3β-hydroxysteroid dehydrogenase (HSD) activity and protein abundance were observed and this was inhibited in response to APJ and adenosine 5'-monophosphate-activated protein kinase (AMPKα) kinase blockers. In conclusion, the presence of apelin/APJ in the CL of pigs and stimulatory effects of apelin on P4 secretion and 3β-HSD levels suggest potential auto/paracrine regulation by apelin in the luteal phase of the estrous cycle. Moreover, the involvement of APJ and AMPKα kinase in apelin activity in CL was confirmed.

Does signaling of estrogen-related receptors affect structure and function of bank vole Leydig cells?

To get a deeper insight into the function of estrogen-related receptors (ERRs) and dissect underlying mechanism in Leydig cells, ERRs (type α, β and γ) were blocked or activated in testes of adult bank voles (Myodes glareolus) which show seasonal changes in the intratesticular sex hormones level. Both actively reproducing animals (long day conditions; LD) and those with regression of the reproductive system (short day conditions; SD) received intraperitoneal injections of selective ERRα antagonist 3-[4-(2,4-Bis-trifluoromethylbenzyloxy)-3-methoxyphenyl]-2-cyano-N-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)acrylamide (XCT 790) or selective ERRβ/ERRγ agonist N-(4-(Diethylaminobenzylidenyl)-N'-(4-hydroxybenzoyl)-hydrazine (DY131) (50 μ/kg bw; six doses every other day). Markedly more, XCT 790 (P < 0.05) but also DY131 affected interstitial tissue histology whose volume increased in both LD and SD males while seminiferous epithelium structure was untouched. Ultrastructure analysis revealed alterations in mitochondria number as well as endoplasmic reticulum and Golgi complexes volume and structure especially after ERRα blockage. Diverse and complex ERRs regulation at mRNA level and protein expression (P < 0.05; P < 0.01 and P < 0.001) of steroidogenic (lutropin receptor (LHR), translocator protein (TSPO), steroidogenic acute regulatory protein (StAR)) and secretory (insulin-like protein 3 (INSL3) and relaxin (RLN)) molecules were revealed in relations to endogenous estrogen level in treated males. Notably, immunolocalization of ERRs and above proteins, exclusively in Leydig cells, indicated their involvement in Leydig cell function control based on interactions with endogenous estrogen level and/or estrogen signaling via ERRs. Treatment with XCT 790 or DY131 significantly decreased (P < 0.05; P < 0.01 and P < 0.001) intratesticular estrogens concentration, with exception in SD DY131 males. In addition, androgens level was decreased, but not in LD DY131 voles. Similarly, ERRβγ activation significantly reduced (P < 0.05; P < 0.01 and P < 0.001) cAMP and calcium ions (Ca²⁺) concentrations particularly in DY131 voles. Overall, for the first time, we have shown that ERRs are involved in maintenance of Leydig cell architecture and supervision of its steroidogenic and secretory activity that is closely related to endogenous estrogen status in the testis. Further understanding of mechanism(s) by which individual types of ERRs can control Leydig cell function is relevant for predicting and preventing steroidogenic and spermatogenic disorders.

Detection of aromatase, androgen, and estrogen receptors in bank vole spermatozoa

Spermatozoa are highly specialized cells which transport a single-copy haploid genome to the site of fertilization. Before this, spermatozoa undergo a series of biochemical and functional modifications. In recent years, the crucial role of androgens and estrogens in proper germ cell differentiation during spermatogenesis has been demonstrated. However, their implication in the biology of mature male gametes is still to be defined. Our study provides evidence for the first time that aromatase, the androgen receptor (AR), as well as the estrogen receptors α and β (ERα and ERβ), are present in bank vole spermatozoa. We demonstrated the region-specific localization of these proteins in bank vole spermatozoa using confocal microscopy. Immunoreactive aromatase was observed in the proximal head region and in both the proximal and distal tail regions, whereas steroid hormone receptors were found only in the proximal region of the sperm head. Protein expression in sperm lysates was detected by Western blot analysis. Immunohistochemical results were analyzed quantitatively. Our results show that bank vole spermatozoa are both a source of estrogens and a target for steroid hormone action. Moreover, the presence of aromatase and steroid hormone receptors in the bank vole spermatozoa indicates a potential function of these proteins during capacitation and/or the acrosome reaction.

Prenatal and neonatal exposure to flutamide affects function of Leydig cells in adult boar

In this study, flutamide, an androgen receptor antagonist, was used as a tool to better understand the role of androgen receptor signaling and androgen signaling disruption during fetal and neonatal periods on porcine Leydig cell development and function. Flutamide, 50 mg kg(-1) d(-1) was administered into pregnant gilts during gestational days 20 to 28 and days 80 to 88 and into male piglets on postnatal days 2 to 10 (PD2). Leydig cells of flutamide-exposed boars, especially those of PD2 males, displayed morphologic alterations, increased size, and occupied increased area (P < 0.001) of the testes when compared with the control. Despite this, testosterone concentrations were reduced significantly in comparison with those of controls (P < 0.05, P < 0.001). Reduced testosterone production in response to flutamide exposure appeared to be related to changes in testosterone metabolism, as shown by increased aromatase mRNA (P < 0.05, P < 0.01), protein expression (P < 0.01, P < 0.001), and elevated estradiol concentrations (P < 0.001). Moreover, impaired Leydig cell responsiveness to LH was indicated by the decreased expression of LH receptor (P < 0.05, P < 0.001). No significant effect of flutamide was found on LH and FSH concentrations. Taken together, our data indicate that flutamide when administered during prenatal or neonatal period have a long-term effect on Leydig cell structure and function, leading to androgen-estrogen imbalance. Leydig cell failure was most evident in adult boars neonatally exposed to flutamide, suggesting that androgen action during neonatal development is of pivotal importance for the differentiation and function of porcine adult Leydig cell population.

Isolation of lipocalin-type protein from rainbow trout seminal plasma and its localisation in the reproductive system

The lipocalin protein family is a large and diverse group of small extracellular proteins characterised by their ability to bind hydrophobic molecules. In the present study, we describe the isolation procedure for rainbow trout seminal plasma protein, characterised by a moderate migration rate during polyacrylamide gel electrophoresis, providing information regarding its basic features and immunohistochemical localisation. This protein was identified as a lipocalin-type protein (LTP). The molecular mass of LTP was found to be 18 848 Da and it was found to lack any carbohydrate components. Only a few Salmoniformes contain LTP in their seminal plasma. The abundance of LTP in the Sertoli and Leydig cells of the testes of the rainbow trout, as well as in secretory cells of the efferent duct, suggests that this protein is specific for rainbow trout milt, where it acts as a lipophilic carrier protein. Moreover, the specific localisation of LTP in the flagella of the spermatozoa suggests a role for LTP in sperm motility. Further experiments are necessary to identify the endogenous ligands for LTP in rainbow trout seminal plasma and to characterise the binding properties of this protein.

Expression of connexin 43 protein in testes, epididymides and prostates of stallions

REASONS FOR PERFORMING STUDY

Connexin 43 (Cx43) is a ubiquitously distributed gap junction protein in testes and other reproductive tissues. Adjacent cells share ions and small metabolites through intercellular channels, which are present in gap junctions. Previously, Cx43 has not been reported in testes, epididymides and prostates either in healthy stallions or cryptorchid horses.

OBJECTIVES

To demonstrate the expression pattern of Cx43 in the reproductive tissues of stallions and examine whether naturally occurring bilateral cryptorchidism has any influence on distribution and expression of Cx43.

METHODS

The expression and the presence of Cx43 protein were detected by means of immunohistochemistry and Western blot analysis using a polyclonal rabbit anti-Cx43 antibody.

RESULTS

In stallions, gap junctions appeared as structures localised to cell-cell contacts between adjacent cells. In testes, Cx43 expression was detected in the interstitial tissue and seminiferous tubules, between Leydig and Sertoli, as well as Sertoli and germ cells. In epididymides, Cx43 was localised between epithelial cells, whereas in prostates, between secretory cells of the glandular epithelium. In the cryptorchid, a clear reduction of Cx43 signal was observed in all reproductive tissues.

CONCLUSIONS

Coupling of Leydig cells via gap junctions may suggest that steroidogenic function of the testis is under the influence of these intercellular channels. Within seminiferous tubules, the expression was found to be stage-specific, pointing to its role in coordinating spermatogenesis. Differential distribution of Cx43 protein in the reproductive tract of normal and cryptorchid stallions indicates that expression is clearly dependent on the physiological status of the horse.

POTENTIAL RELEVANCE

Detection of Cx43 expression in equine testicular, epididymal, and prostatic cells is important for a better understanding of the role of intercellular membrane channels in direct cell communication within the reproductive tract of stallions.

Morphology and function of human Leydig cells in vitro. Immunocytochemical and radioimmunological analyses

The aim of our study was to show whether the cells isolated from testes of patients underwent bilateral orchiectomy for prostatic cancer are able to grown in vitro, and if so, are functionally active. Immuncytochemistry was performed to show the functional status of human cultured cells. In detail, immunolocalization of luteinizing hormone receptors (LHR), mitochondria, and cytoskeletal elements was demonstrated. Moreover, radioimmunological assay was used to measure testosterone secretion by cultured Leydig cells. Using Nomarski interference contrast and fine immunofluorescence analysis the positive immunostaining for LHR was observed in almost all Leydig cells, however it was of various intensity in individual cells. Testosterone measurement revealed significant difference between testosterone secretion by hCG-stimulated and unstimulated Leydig cells (p<0.05). Moreover, testosterone levels were significantly higher in 24- and 48- hour-cultures than in those of 72 hrs (p<0.05). Morphological analysis of Leydig cells in culture revealed the presence of mononuclear and multinucleate cells. The latter cells occurred in both hCG-stimulated and unstimulated cultures. In Leydig cells labeled with a molecular marker MitoTtracker, an abundance of mitochondria and typical distribution of microtubules and microfilaments were observed irrespective of the number of nuclei within the cell, suggesting no functional differences between mono- and multinucleate human Leydig cells in vitro. Since the percentage of multinucleate cells was similar in both hCG-stimulated and unstimulated cultures (23.70% and 22.80%), respectively, the appearance of these cell population seems to be independent of hormonal stimulation.

Morphology and function of human Leydig cells in vitro. Immunocytochemical and radioimmunological analyses

The aim of our study was to show whether the cells isolated from testes of patients underwent bilateral orchiectomy for prostatic cancer are able to grown in vitro, and if so, are functionally active. Immuncytochemistry was performed to show the functional status of human cultured cells. In detail, immunolocalization of luteinizing hormone receptors (LHR), mitochondria, and cytoskeletal elements was demonstrated. Moreover, radioimmunological assay was used to measure testosterone secretion by cultured Leydig cells. Using Nomarski interference contrast and fine immunofluorescence analysis the positive immunostaining for LHR was observed in almost all Leydig cells, however it was of various intensity in individual cells. Testosterone measurement revealed significant difference between testosterone secretion by hCG-stimulated and unstimulated Leydig cells (p<0.05). Moreover, testosterone levels were significantly higher in 24- and 48-hour-cultures than in those of 72 hrs (p<0.05). Morphological analysis of Leydig cells in culture revealed the presence of mononuclear and multinucleate cells. The latter cells occurred in both hCG-stimulated and unstimulated cultures. In Leydig cells labeled with a molecular marker MitoTtracker, an abundance of mitochondria and typical distribution of microtubules and microfilaments were observed irrespective of the number of nuclei within the cell, suggesting no functional differences between mono- and multinucleate human Leydig cells in vitro. Since the percentage of multinucleate cells was similar in both hCG-stimulated and unstimulated cultures (23.70% and 22.80%), respectively, the appearance of these cell population seems to be independent of hormonal stimulation.

141. DEVELOPMENT OF A MODEL SYSTEM TO ASSESS THE REGULATION OF LEYDIG STEM CELL DIFFERENTIATION

The Leydig cells of the testis are responsible for the production of ca. 95% of all circulating androgens in the adult male. There is substantial evidence now that loss of Leydig cell (LC) functionality may account in part for declining androgen levels in the ageing male. Some of this loss of functionality appears to be due to disruption of early LC differentiation processes caused by exposure to environmental endocrine disrupting substances. We have made use of the ability of the alkylating agent ethane dimethane sulfonate (EDS) to destroy specifically all immature and adult LC to develop a model system which allows us to quantitatively assess the differentiation of a new population of LC from resident stem cells in the testis. Following a single bolus injection of EDS into adult Sprague Dawley rats, unless additional testosterone is present to suppress the HPG axis, new LC redifferentiate from the resident stem cells in the testis. These are small spindle-shaped mesenchymal cells which are located in the peritubular region adjacent to the seminiferous tubules. In the absence of mature LC these mesenchymal cells differentiate first into LC progenitor cells, then immature LC, and finally into adult LC, following a precisely defined kinetic which can be mapped using quantitative RT-PCR for LC specific genes in whole testis samples. We are using this model to examine the effect of in vivo application of known environmental endocrine disrupting agents on LC differentiation, and hence their potential to cause long-term loss of LC functionality.

Connexin 43 expression in human and mouse testes with impaired spermatogenesis

Connexin 43 (Cx43) belongs to a family of proteins that form gap junction channels. The aim of this study was to examine the expression of Cx43 in the testis of a patient with Klinefelter's syndrome and of mice with the mosaic mutation and a partial deletion in the long arm of the Y chromosome. These genetic disorders are characterized by the presence of numerous degenerated seminiferous tubules and impaired spermatogenesis. In mouse testes, the expression and presence of Cx43 were detected by means of immunohistochemistry and Western blot analysis, respectively. In testes of Klinefelter's patient only immunoexpression of Cx43 was detected. Regardless of the species Cx43 protein was ubiquitously distributed in testes of reproductively normal males, whereas in those with testicular disorders either a weak intensity of staining or no staining within the seminiferous tubules was observed. Moderate to strong or very strong staining was confined to the interstitial tissue. In an immunoblot analysis of testicular homogenates Cx43 appeared as one major band of approximately 43 kDa. Our study adds three more examples of pathological gonads in which the absence or apparent decrease of Cx43 expression within the seminiferous tubules was found. A positive correlation between severe spermatogenic impairment and loss of Cx43 immunoreactivity observed in this study supports previous data that gap junctions play a crucial role in spermatogenesis. Strong Cx43 expression detected mostly in the interstitial tissue of the Klinefelter's patient may presumably be of importance in sustaining Leydig cell metabolic activity. However, the role of gap junction communication in the control of Leydig cell function seems to be more complex than originally thought.

Testicular morphology and expression of aromatase in testes of mice with the mosaic mutation (Atp7a mo-ms)

The aim of this study was to determine whether testicular cells of mice with the mosaic mutation, associated with abnormal copper metabolism, are able to aromatize androgens to estrogens, and what is the putative role of estrogens in the gonad of the mutant male. Mosaic is a lethal mutation; affected males usually die on about day 16. Those, which survive to reach sexual maturity, are valuable research subjects. In testes of young and adult mutants, histological analysis revealed the presence of many degenerating seminiferous tubules besides normal-looking ones. Additionally, high numbers of apoptotic germ cells were observed, especially in young mutants when compared with the controls. Positive immunostaining for aromatase was found in cultured Leydig cells and testicular sections of both control and mutant males. The intensity of immunostaining was always stronger in the mosaic mice. In both groups, Western-blot analysis revealed the presence of aromatase protein as a single band of approximately 55 kDa. In the mosaic males, levels of testosterone in cultured Leydig cells, whole testes, and in blood plasma were lower than in those of the respective controls. On the contrary, estradiol concentrations were always higher in the mutants. Both in vivo and in vitro studies indicate that morphological and functional changes in the testes of the mosaic mice mainly result from defective copper metabolism. The higher level of endogenous estrogens can additionally enhance morphological alterations within the testes. It seems also likely that excess estrogens may affect the survival rate of the mosaic males.

Hormonal status of male reproductive system: androgens and estrogens in the testis and epididymis. In vivo and in vitro approaches

The purpose of this article was to summarize our results on the role of androgens and estrogens in human, rodent and equine testes and epididymides, in both, physiological and patological conditions, obtained in the space of the Solicited Project (084/PO6/2002) financially supported by the State Committee for Scientific Research during the last three years. Testosterone produced by Leydig cells of the testes is clearly the major androgen in the circulation of men and adult males of most mammalian species. However, androgen metabolites make up a significant fraction of total circulating steroids. Moreover, androgen metabolism may proceed to amplify the action of testosterone through its conversion to dihydrotestosterone (DHT) or its aromatization to estradiol. The distribution of androgen and estrogen receptors (ARs and ERs) within male reproductive tissues is important because of their crucial role in mediating androgen and/or estrogen action. Attempts were undertaken to discuss not only the role of aromatase and ERs in mediating the action of estrogens in the male, but also the importance of DHT in hormonal regulation of the epididymis. In the latter, alterations caused by finasteride treatment and lead-induced oxidative stress are described. Male reproductive function of the testis and epididymis reflected by the alterations in enzymatic activity, distribution of steroid hormone receptors, differences in steroid hormone levels and altered gene expression of antioxidant enzymes are also discussed.

The expression of aromatase, estrogen receptor alpha and estrogen receptor beta in mouse Leydig cells in vitro that derived from cryptorchid males

A broad expression of aromatase and estrogen receptors (ERs) in the testis suggests an important role for estrogens in regulating testicular cell function and reproductive events. The aim of the present study was to show whether Leydig cells in vitro isolated from cryptorchid testes of two inbred strains of mice, KE and CBA, are a site of estrogen synthesis. Using immunocytochemistry, aromatase, estrogen receptor alpha(ERalpha), and estrogen receptor beta(ERbeta) were localized in cultured Leydig cells. Immunoreactive aromatase was found in the cytoplasm of control Leydig cells and those isolated from cryptorchid males, however the intensity of immunostaining was different, being stronger in Leydig cells deriving from cryptorchid mice. The strongest aromatase immunostaining was found in cryptorchid-KE Leydig cells. Strong immunoexpression of ERalpha was detected in the nuclei of both KE-and CBA-Leydig cells. The intensity of ERalpha immunostaining was stronger in cultured cells deriving from cryptorchid testes. ERbeta immunoexpression was detected predominantly in KE-Leydig cells. Control CBA-Leydig cells were negative for ERbeta or the result was inconclusive, whereas in cryptorchid CBA-Leydig cells a weak immunostaining was present in their nuclei. Western blot analysis confirmed the results obtained by immunocytochemistry. In KE- and CBA-Leydig cells aromatase as a band of 55 kDa protein was present, whereas ERalpha molecular weight was 67 kDa on Western blots. No band was detected for ERbeta. Radioimmunological analysis revealed that androgen and estrogen levels secreted by Leydig cells in vitro were strain-dependent. Additionally, in KE-Leydig cells that derived from cryptorchid mice estrogen level was distinctly higher in comparison with that of the respective control.

Immunodetection of aromatase in mice with a partial deletion in the long arm of the Y chromosome

Aromatization of androgens into estrogens is catalyzed by a microsomal enzyme, P450 aromatase. Males of the mouse strain B10.BR and its congenic mutant strain B10.BR-Ydel (with a partial deletion in the long arm of the Y chromosome) were used to identify the cellular source of estrogens within the testis. Immunocytochemistry was applied to localize aromatase in cultured Leydig cells, cytoplasmic droplets attached to flagella of spermatozoa, and sections of testes. The presence of aromatase in testes was checked by means of Western-blot analysis. Steroid hormones secreted by Leydig cells in vitro were measured in homogenates of testes using radioimmunological methods. Additionally, a Southern analysis was performed using the Y353/B probe to check the length of the deletion in the Y chromosome. In sections of testis of B10.BR mice, weak to moderate immunohistochemical staining of aromatase was found in Leydig cells, Sertoli cells, and germ cells. In testicular cells of B10.BR-Ydel mice, stronger immunostaining of aromatase was observed, especially in germ cells and Leydig cells. Positivity for aromatase was also found in the cytoplasm of cultured Leydig cells from both strains, but it was higher in cells derived from mutant males. Western-blot analysis revealed one major band of approx. 55kDa of aromatase in testes from both strains. Lower testosterone levels were found in mutant males in supernatants of culture media and homogenates of testes in comparison with control males. In contrast, estradiol levels were always higher in mutants. Therefore, it seems likely that the increased expression of aromatase and, as a consequence, the higher levels of endogenous estrogens enhance the morphological alterations in testis and affect spermatogenesis in mutant males.

Immunoexpression of androgen receptors and aromatase in testes of patient with Klinefelter's syndrome

Klinefelter's syndrome (47, XXY) is the most common chromosome aneuploidy in men and is usually characterized by underdeveloped testes and sterility. The aim of the present study was to detect cellular distribution of androgen receptors (AR) and aromatase in testes of patient with KS. The tissue sections were processed for morphological and immunohistochemical staining. Additionally, levels of FSH, LH, PRL, estradiol, and testosterone were measured in the plasma. Morphological analysis revealed a complete absence of spermatogenesis. No germ cells were present in seminiferous tubules. In some tubules, nests of apparently degenerating Sertoli cells were found. In the interstitium, Leydig cell hyperplasia was observed. Using immunohistochemistry, nuclear AR staining was detected in Sertoli cells and peritubular cells, whereas in Leydig cells the staining was exclusively cytoplasmic. The immunostaining of aromatase was detected in the cytoplasm of Sertoli cells and Leydig cells. Increased levels of gonadotropins and decreased level of testosterone concomitantly with the cytoplasmic localization of AR in Leydig cells might contribute to the impaired testicular function in patient with KS.

Complementary approaches demonstrate that cellular aromatization in the bank vole testis is related to photoperiod

A growing body of evidence indicates that germ cells, at least in several mammalian species, are responsible for estrogen formation since they possess active aromatase. In seasonally breeding rodent, the bank vole, the length of photoperiod seems to be the primary environmental factor regulating annual changes in the reproductive activity. However, in this species gonadal steroidogenesis is still not well understood, neither the site of aromatization in testicular cells. In the bank vole testis, aromatase visualized by immunohistochemistry was found in Leydig cells, Sertoli cells, and germ cells: especially in spermatocytes and spermatids. Moreover, in the immuno-electron microscopic study, gold particles indicating aromatase were observed over the cytoplasm of elongated spermatids. The presence of aromatase and the activity of this enzyme were found in microsomal preparations of the whole testes and those of seminiferous tubules. This was measured by means of Western blot and the biochemical assay with tritiated androstenedione, respectively. Additionally, using radioimmunological assays testosterone and estradiol concentrations in homogenates were detected. All the studied parameters revealed close correlation with the length of photoperiod being evidently higher in animals kept in the long day conditions when compared with those from short light cycles.

Androgen aromatization in cryptorchid mouse testis

Estrogens play an important role in germ cell development. Therefore, we have studied expression patterns of aromatase that converts testosterone into estrogens in 2 recombinant inbred mouse strains that differ in efficiency of spermatogenesis. In order to show whether germ cells are a target for estrogens, estrogen receptors (ER)alpha and beta were localized as well. Adult male CBA and KE mice were made unilaterally cryptorchid to determine alterations in testicular steroidogenesis and spermatogenesis. Differences between control and cryptorchid testes have been studied with respect to (1) cellular sites of aromatase, the enzyme responsible for estrogen formation, (2) the presence of ERalpha and ERbeta in various types of testicular cells, and (3) steroidogenic activity in the testes. Additionally, unilaterally control testes of cryptorchid mice were compared with bilaterally descended testes. Histological or hormonal differences were not found between control testes of cryptorchid and untreated mice. In cryptorchid testes from both strains, degeneration of germ cells was observed as well as a decrease in size of the seminiferous tubules, whereas the amount of interstitial tissue increased, especially in testes of CBA mice. Using immunohistochemistry, aromatase was localized in Leydig cells and germ cells in both control and cryptorchid testes. Sertoli cells were immunopositive in control testes only. In cryptorchid testes of KE mice, aromatase was strongly expressed in spermatids, that were still present in a few tubules. Other cell types in tubules were negative for aromatase. In both control and cryptorchid testes of both mouse strains, ERalpha were present in Leydig cells only, whereas ERbeta were found in Leydig cells and in germ cells in early stages of maturation. In homogenates of testes of CBA control mice, testosterone levels were 3-fold higher than in those of control KE mice, whereas the difference in estradiol levels between both strains was small. Cryptorchidism resulted in decreased testosterone levels and increased estradiol levels. The results of the present study show functional alterations due to cryptorchidism in both mouse strains. Strong aromatase expression in germ cells in control and cryptorchid testes indicates an additional source of estrogens in the testis besides the interstitial tissue and the relevance of estrogen in spermatogenesis.