Evidence for similar expression of protein C inhibitor and the urokinase-type plasminogen activator system during mouse testis development

Analysis of histomorphology and SERNINA5 gene expression in different regions of epididymis of cattleyak

The molecular mechanism of sterility in cattleyak is still unresolved. The related factors of infertility in cattleyak were studied by tissue section, SERPINA5 gene cloning and bioinformatics technology. Tissue sections of the epididymis showed poorly structured and disorganized epithelial cells in the corpus of the epididymis compared to the caput of the epididymis, while in the cauda part of the epididymis, the extra basal smooth muscle was thinner, the surface of the epithelial lumen was discontinuous and the epithelium was markedly degenerated. The results of gene cloning showed that the coding sequence (CDS) region of the SERPINA5 gene in cattleyak was 1215 bp in length, encoding a total of 404 amino acids, of which the isoleucine content was the highest, accounting for a total of 49 amino acids (12.1%). The results of real-time fluorescence quantitative PCR (qPCR) showed that the expression of the SERPINA5 gene in the epididymis caput in cattleyak was significantly higher than that in the corpus and cauda (P < 0.05), but there were no significant differences between the corpus and cauda. In the current study, histological and bioinformatics analysis, physicochemical properties, and the expression analysis of the SERPINA5 gene in different regions of the epididymis in cattleyak were carried out to explore the biological complications of cattleyak infertility.

New Insights on Sperm Function in Male Infertility of Unknown Origin: A Multimodal Approach

The global trend of rising (male) infertility is concerning, and the unidentifiable causes in half of the cases, the so-called unknown origin male infertility (UOMI), demands a better understanding and assessment of both external/internal factors and mechanisms potentially involved. In this work, it was our aim to obtain new insight on UOMI, specifically on idiopathic (ID) and Unexplained male infertility (UMI), relying on a detailed evaluation of the male gamete, including functional, metabolic and proteomic aspects. For this purpose, 1114 semen samples, from males in couples seeking infertility treatment, were collected at the Reproductive Medicine Unit from the Centro Hospitalar e Universitário de Coimbra (CHUC), from July 2018-July 2022. Based on the couples' clinical data, seminal/hormonal analysis, and strict eligibility criteria, samples were categorized in 3 groups, control (CTRL), ID and UMI. Lifestyle factors and anxiety/depression symptoms were assessed via survey. Sperm samples were evaluated functionally, mitochondrially and using proteomics. The results of Assisted Reproduction Techniques were assessed whenever available. According to our results, ID patients presented the worst sperm functional profile, while UMI patients were similar to controls. The proteomic analysis revealed 145 differentially expressed proteins, 8 of which were specifically altered in ID and UMI samples. Acrosin (ACRO) and sperm acrosome membrane-associated protein 4 (SACA4) were downregulated in ID patients while laminin subunit beta-2 (LAMB2), mannose 6-phosphate isomerase (MPI), ATP-dependent 6-phosphofructokinase liver type (PFKAL), STAR domain-containing protein 10 (STA10), serotransferrin (TRFE) and exportin-2 (XPO2) were downregulated in UMI patients. Using random forest analysis, SACA4 and LAMB2 were identified as the sperm proteins with a higher chance of distinguishing ID and UMI patients, and their function and expression variation were in accordance with the functional results. No alterations were observed in terms of lifestyle and psychological factors among the 3 groups. These findings obtained in an experimental setting based on 3 well-defined groups of subjects, might help to validate new biomarkers for unknown origin male infertility (ID and UMI) that, in the future, can be used to improve diagnostics and treatments.

Molecular genetic mechanisms of teratozoospermia

In recent years, the incidence of teratospermia has been increasing, and it has become a very important factor leading to male infertility. The research on the molecular mechanism of teratospermia is also progressing rapidly. This article briefly summarizes the clinical incidence of teratozoospermia, and makes a retrospective summary of related studies reported in recent years. Specifically discussing the relationship between gene status and spermatozoa, the review aims to provide the basis for the genetic diagnosis and gene therapy of teratozoospermia.

Complementing Testicular Immune Regulation: The Relationship between Sertoli Cells, Complement, and the Immune Response

Sertoli cells within the testis are instrumental in providing an environment for spermatogenesis and protecting the developing germ cells from detrimental immune responses which could affect fertility. Though these immune responses consist of many immune processes, this review focuses on the understudied complement system. Complement consists of 50+ proteins including regulatory proteins, immune receptors, and a cascade of proteolytic cleavages resulting in target cell destruction. In the testis, Sertoli cells protect the germ cells from autoimmune destruction by creating an immunoregulatory environment. Most studies on Sertoli cells and complement have been conducted in transplantation models, which are effective in studying immune regulation during robust rejection responses. In grafts, Sertoli cells survive activated complement, have decreased deposition of complement fragments, and express many complement inhibitors. Moreover, the grafts have delayed infiltration of immune cells and contain increased infiltration of immunosuppressive regulatory T cells as compared to rejecting grafts. Additionally, anti-sperm antibodies and lymphocyte infiltration have been detected in up to 50% and 30% of infertile testes, respectively. This review seeks to provide an updated overview of the complement system, describe its relationship with immune cells, and explain how Sertoli cells may regulate complement in immunoprotection. Identifying the mechanism Sertoli cells use to protect themselves and germ cells against complement and immune destruction is relevant for male reproduction, autoimmunity, and transplantation.

The Urokinase-Type Plasminogen Activator Contributes to cAMP-Induced Steroidogenesis in MA-10 Leydig Cells

Leydig cells produce androgens which are essential for male sex differentiation and reproductive functions. Steroidogenesis, as well as expression of several genes in Leydig cells, are stimulated by LH/cAMP and repressed by AMP/AMPK. One of those genes is Plau, which codes for the urokinase-type plasminogen activator (uPA), a secreted serine protease. The role of uPA and the regulation of Plau expression in Leydig cells remain unknown. Using siRNA-mediated knockdown, uPA was required for maximal cAMP-induced STAR and steroid hormone production in MA-10 Leydig cells. Analysis of Plau mRNA levels and promoter activity revealed that its expression is strongly induced by cAMP; this induction is blunted by AMPK. The cAMP-responsive region was located, in part, in the proximal Plau promoter that contains a species-conserved GC box at −56 bp. The transcription factor Krüppel-like factor 6 (KLF6) activated the Plau promoter. Mutation of the GC box at −56 bp abolished KLF6-mediated activation and significantly reduced cAMP-induced Plau promoter activity. These data define a role for uPA in Leydig cell steroidogenesis and provide insights into the regulation of Plau gene expression in these cells.

Clinical Efficacy of Prodom-Assisted Urokinase in the Treatment of Male Infertility Caused by Impaired Semen Liquefaction

PURPOSE

To evaluate the clinical efficacy of prodom in the administration of urokinase in the vagina in couples with impaired semen liquefaction.

MATERIALS AND METHODS

Overall, 261 patients with impaired semen liquefaction were randomly divided into prodom-assisted urokinase treatment (PAUT) group (n = 91), syringe-assisted urokinase treatment (SAUT) group (n = 86), and traditional treatment (TT) group (n = 84) in the first stage. If the first stage of treatment failed, other treatment methods were initiated instead and the patients were grouped according to the newer treatment method in the second stage. The pregnancy rate, time-to-conception, and treatment costs were evaluated in each group.

RESULTS

In the first stage, the pregnancy rate in the PAUT, SAUT, and TT groups was 69.23%, 29.07%, and 22.62%, respectively; the time-to-conception was 2.66 ± 1.44, 3.69 ± 2.61, and 3.86 ± 3.00 months, respectively; the treatment costs were 658.18 ± 398.40, 666.67 ± 507.50, and 680.56 ± 480.94 $, respectively. The pregnancy rate and time-to-conception were different in the PAUT group compared with those in SAUT and TT groups (all P < 0.05). However, the difference in treatment costs was not significant (P = 0.717). In the second stage, 154 nonpregnant patients were divided into nine treatment groups, and the effects of changing TT to PAUT on the pregnancy rate, time-to-conception, and treatment costs were observed to be different from those of other treatments (all P < 0.05).

CONCLUSION

Prodom-assisted urokinase can effectively treat male infertility secondary to impaired semen liquefaction.

Comprehensive analysis of long noncoding RNA and mRNA expression patterns in sheep testicular maturation

Long noncoding RNAs (LncRNAs) have been identified as important regulators of testis development; however, their expression patterns and roles in sheep are not yet clear. Thus, we used stranded specific RNA-seq to profile the testis transcriptome (lncRNAs and mRNAs) in premature and mature sheep. Hormone levels and the testis index were examined, and histological analyses were performed at five stages of testis development, 5-day-old (D5), 3-month-old (3M), 6-month-old (6M), 9-month-old (9M), and 2-year-old (2Y), the results of which indicate a significant difference in hormone levels and testis morphometries between the 3M and 9M stages (P < 0.05). Based on the comparison between 3M and 9M samples, we found 1,118 differentially expressed (DE) lncRNAs and 7,253 DE mRNAs in the testes, and qRT-PCR analysis showed that the results correlated well with the transcriptome data. Furthermore, we constructed lncRNA-protein-coding gene interaction networks. Forty-seven DE lncRNA-targeted genes enriched for male reproduction were obtained by cis- and trans-acting; 51 DE lncRNAs and 45 cis-targets, 2 DE lncRNAs and 2 trans-targets were involved in this network. Of these, 5 lncRNAs and their targets, PRKCD, NANOS3, SERPINA5, and CYP19A1, were enriched for spermatogenesis and male gonad development signaling pathways. We further examined the expression levels of 5 candidate lncRNAs and their target genes during testis development. Lastly, the interaction of lncRNA TCONS__00863147 and its target gene PRKCD was validated in vitro in sheep Leydig cells. This study provides a valuable resource for further study of lncRNA function in sheep testis development and spermatogenesis.

Transcriptomic analysis of mRNA expression and alternative splicing during mouse sex determination

Mammalian sex determination hinges on sexually dimorphic transcriptional programs in developing fetal gonads. A comprehensive view of these programs is crucial for understanding the normal development of fetal testes and ovaries and the etiology of human disorders of sex development (DSDs), many of which remain unexplained. Using strand-specific RNA-sequencing, we characterized the mouse fetal gonadal transcriptome from 10.5 to 13.5 days post coitum, a key time window in sex determination and gonad development. Our dataset benefits from a greater sensitivity, accuracy and dynamic range compared to microarray studies, allows global dynamics and sex-specificity of gene expression to be assessed, and provides a window to non-transcriptional events such as alternative splicing. Spliceomic analysis uncovered female-specific regulation of Lef1 splicing, which may contribute to the enhanced WNT signaling activity in XX gonads. We provide a user-friendly visualization tool for the complete transcriptomic and spliceomic dataset as a resource for the field.

Expression of matrix metalloproteinase-13 (MMP-13) in the testes of growing and adult chicken

Although several matrix metalloproteinases (MMPs) have been implicated in testis development, the presence of MMP-13 protein has not been directly substantiated in the male avian gonads. In this study, we examined the expression patterns of MMP-13 and MMP inhibitors, TIMP-1 and TIMP-2, in immature (4weeks), pre-pubertal (16weeks), and mature (1year) chicken testes. Using RT-PCR analysis, we observed that MMP-13 mRNA was expressed in immature testis. In Western blot analysis, the expression level of MMP-13 protein peaked in the immature testes during marked tissue remodeling, whereas it gradually decreased during testis maturation. High expression levels of TIMP-1 (34-kDa) and TIMP-2 (55-kDa) were detected only in immature and pre-pubertal testes and not in adult testis. Four different forms of TIMP-2 protein were differentially detected in the testes of growing and adult chicken. Using immunohistochemistry we localized both secreted and intracellular forms of MMP-13, TIMP-1, and TIMP-2 proteins. These proteins were temporally and spatially distributed in growing and adult testes, and all their expression levels were similar to the expression profile of Western blot results. These findings suggest that age-related changes of MMP-13 with balance of TIMPs act in concert to effect the controlled testicular remodeling and maturation.

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 5: intercellular junctions and contacts between germs cells and Sertoli cells and their regulatory interactions, testicular cholesterol, and genes/proteins associated with more than one germ cell generation

In the testis, cell adhesion and junctional molecules permit specific interactions and intracellular communication between germ and Sertoli cells and apposed Sertoli cells. Among the many adhesion family of proteins, NCAM, nectin and nectin-like, catenins, and cadherens will be discussed, along with gap junctions between germ and Sertoli cells and the many members of the connexin family. The blood-testis barrier separates the haploid spermatids from blood borne elements. In the barrier, the intercellular junctions consist of many proteins such as occludin, tricellulin, and claudins. Changes in the expression of cell adhesion molecules are also an essential part of the mechanism that allows germ cells to move from the basal compartment of the seminiferous tubule to the adluminal compartment thus crossing the blood-testis barrier and well-defined proteins have been shown to assist in this process. Several structural components show interactions between germ cells to Sertoli cells such as the ectoplasmic specialization which are more closely related to Sertoli cells and tubulobulbar complexes that are processes of elongating spermatids embedded into Sertoli cells. Germ cells also modify several Sertoli functions and this also appears to be the case for residual bodies. Cholesterol plays a significant role during spermatogenesis and is essential for germ cell development. Lastly, we list genes/proteins that are expressed not only in any one specific generation of germ cells but across more than one generation.

Expression patterns of protein C inhibitor in mouse development

Proteolysis of extracellular matrix is an important requirement for embryonic development and is instrumental in processes such as morphogenesis, angiogenesis, and cell migration. Efficient remodeling requires controlled spatio-temporal expression of both the proteases and their inhibitors. Protein C inhibitor (PCI) effectively blocks a range of serine proteases, and recently has been suggested to play a role in cell differentiation and angiogenesis. In this study, we mapped the expression pattern of PCI throughout mouse development using in situ hybridization and immunohistochemistry. We detected a wide-spread, yet distinct expression pattern with prominent PCI levels in skin including vibrissae, and in fore- and hindgut. Further sites of PCI expression were choroid plexus of brain ventricles, heart, skeletal muscles, urogenital tract, and cartilages. A strong and stage-dependent PCI expression was observed in the developing lung. In the pseudoglandular stage, PCI expression was present in distal branching tubules whereas proximal tubules did not express PCI. Later in development, in the saccular stage, PCI expression was restricted to distal bronchioli whereas sacculi did not express PCI. PCI expression declined in postnatal stages and was not detected in adult lungs. In general, embryonic PCI expression indicates multifunctional roles of PCI during mouse development. The expression pattern of PCI during lung development suggests its possible involvement in lung morphogenesis and angiogenesis.

A comprehensive survey of the laminins and collagens type IV expressed in mouse Leydig cells and their regulation by LH/hCG

Extracellular matrix (ECM) proteins have been shown to alter Leydig cell steroidogenesis in vitro, substantiating the hypothesis that Leydig cell steroidogenic activity and matrix environment are interdependent events. However, the nature of the ECM components synthesized by Leydig cells and their regulation by LH/human chorionic gonadotropin (hCG) remain unknown. Here, we examine the occurrence of the 11 laminin subunits and the 6 alpha chains of collagen IV (COL4A1-6) by RT-PCR in Leydig cells cultured with or without LH/hCG. Leydig cells were a tumor Leydig cell line (mLTC-1) or 8-week-old mice Leydig cells. Based on PCR data, it is suggested that normal Leydig cells may synthesize a maximum of 11 laminin heterotrimers and the 6 alpha chains of collagen IV. They also may synthesize various proteases and inhibitors of the metzincin family. The mLTC-1 cells have a limited repertoire as compared with normal Leydig cells. Interestingly, none of the ten proteases and inhibitors monitored is under LH-hCG regulation whereas every protease and inhibitor of the serine protease family yet identified in Leydig cells is under gonadotropin regulation. In addition, a few laminin and collagen subunit genes are regulated by LH/hCG. These are laminins alpha3 and gamma3 (Lama3 and Lamc3), Col4a3, and Col4a6, which are negatively regulated by LH/hCG in both Leydig cell types, and Col4a4, which was downregulated in primary cultures but not in mLTC-1 cells. Collectively, the present study suggests that Leydig cells modulate in a selective fashion their matrix environment in response to their trophic hormone. This may alter the steroidogenic outcome of Leydig cells.

Serine proteases and serine protease inhibitors in testicular physiology: the plasminogen activation system

The testis is an organ in which a series of radical remodeling events occurs during development and in adult life. These events likely rely on a sophisticated network of proteases and complementary inhibitors, including the plasminogen activation system. This review summarizes our current knowledge on the testicular occurrence and expression pattern of members of the plasminogen activation system. The various predicted functions for these molecules in the establishment and maintenance of the testicular architecture and in the process of spermatogenesis are presented.

Immunolocalization of protein C inhibitor in differentiation of human epidermal keratinocytes

Keratinocytes propagated in low calcium (0.05 mM) serum-free medium grow as monolayers and exhibit morphological and biosynthetic phenotypes similar to the keratinocytes of the basal layer in normal epidermis. When the calcium in the medium is increased to 1.5 mM, the keratinocytes start to stratify and differentiate. Such differentiation is important in the formation of an epidermal barrier. Proteolysis plays a crucial role in the process. The functions of most of the plasminogen activator cascade components in human skin have been studied, but little was known about the expression and role of protein C inhibitor in the differentiation of human epidermal keratinocytes. In the present study, we used immunohistochemistry and immunocytochemistry to examine the immunolocalization of protein C inhibitor in normal human skin and in cultured keratinocytes in serum-free medium with low and high calcium, respectively. The results indicated that protein C inhibitor is mainly localized in superficial and more differentiated keratinocytes in normal human epidermis. Keratinocytes positive for protein C inhibitor were detected in cultures containing both low and high calcium media, and the level of protein C inhibitor was increased in high calcium medium. This increase was accompanied by an altered intracellular distribution, from the perinuclear cytoplasm in undifferentiated keratinocytes to the whole cytoplasm in differentiated keratinocytes. Further study revealed that protein C inhibitor was incorporated into the cornified envelope in normal skin keratinocytes and cultured differentiated keratinocytes. Our results suggest that protein C inhibitor may be involved in the differentiation of keratinocytes.

Inhibition of the urokinase-type plasminogen activator by triplex-forming oligonucleotides in rat Sertoli cells: a new contraceptive alternative?

Urokinase-type plasminogen activator (uPA), expressed in Sertoli cells in the testis, is closely related with tight junctions of blood-testis barrier (BTB), and it has been considered as a potential contraceptive target. In the present study, the antigene effects of triplex-forming oligodeoxynucleotides (TFO) targeting uPA in rat Sertoli cells were investigated in vitro. The stable triplexes, formed by uPA specific TFOs under physiological conditions, were tested by means of electrophoretic mobility shift assays (EMSA). Although tPA, another form of plasminogen activators (PAs), partially compensated the lose of PAs activities, uPA mRNA and protein were significantly reduced as demonstrated by real-time reverse transcription PCR and a chromogenic assay, after the treatment of Sertoli cells with uPA specific TFOs at a concentration of 330 nM. The capacity of TFOs resistance to nuclease degradation was enhanced by the phosphorothioated on the backbone of the oligonucleotides. Our results indicated that the TFOs can downregulate uPA expression and uPA might be an alternative contraceptive target.

Male fertility and protein C inhibitor/plasminogen activator inhibitor-3 (PCI): localization of PCI in mouse testis and failure of single plasminogen activator knockout to restore spermatogenesis in PCI-deficient mice

OBJECTIVE

To investigate the mechanisms responsible for the testicular abnormalities and infertility of previously generated male protein C inhibitor (PCI)-deficient mice.

DESIGN

Determination of the localization of PCI in the reproductive organs of wild-type males. Generation of double knockout mice lacking the protease inhibitor PCI and one plasminogen activator, either urokinase (uPA) or tissue plasminogen activator (tPA), both of which are PCI-target proteases.

SETTING

Animal research and histologic analysis.

ANIMAL(S)

Male mice of desired genotype.

INTERVENTION(S)

Fertility testing of double knockout mice.

MAIN OUTCOME MEASURE(S)

Infertility of PCI(-/-)uPA(-/-) and PCI(-/-)tPA(-/-) double knockout mice.

RESULT(S)

In the testes of wild-type males PCI was detected in spermatocytes of prophase I, as well as in late spermatids and mature spermatozoa, but absent from somatic cells. All PCI(-/-) uPA(-/-) and PCI(-/-) tPA(-/-) male mice were infertile and histologic analysis of testis showed similar alterations as previously described for PCI(-/-) mice.

CONCLUSION(S)

The abnormal spermatogenesis of PCI (plasminogen activator inhibitor-3)-deficient mice cannot be rescued by single plasminogen activator knockout.

A male reproduction-related Kazal-type peptidase inhibitor gene in the prawn, Macrobrachium rosenbergii: molecular characterization and expression patterns

Peptidase inhibitors in the male reproductive tract are well known in mammals, in which they play roles in protecting the tract epithelium against proteolytic damage or in regulating the fertilization process. By screening the subtracted cDNA clones enriched for male reproductive tract-specific transcripts, one clone encoding a putative protein that showed significant similarity to Kazal-type peptidase inhibitor (KPI) was obtained. This is the first report of an invertebrate in which a male reproductive tract-specific KPI gene has been identified and characterized. The gene contains a 405-bp open reading frame (ORF), a 72 bp 5' untranslated region (UTR), and a 259 bp 3' UTR. The conceptually translated protein consisted of a 21-amino-acid signal peptide and a 113-amino-acid mature polypeptide with two Kazal-type domains (named after the discoverer). Significant levels of the mRNA were observed only in the male reproductive tract, while mRNA expression was not detected in any other tissues tested. The transcription of the gene remained constant during maturation, although not in the postlarval stage. In situ hybridization demonstrated the presence of the mRNA in the secretory epithelial cells of vas deferens and terminal ampullae.

Expression of serpinb6 serpins in germ and somatic cells of mouse gonads

The serpin superfamily of serine protease inhibitors is implicated in the regulation of numerous physiological processes. In mice, Spi3/Serpinb6 has a broad tissue distribution. We have investigated the expression of Serpinb6 family members in embryonic and adult gonads. In male and female mice, Spi3/Serpinb6 and NK13/Serpinb6b were expressed in developing gonads and in both somatic and germ cells of adult gonads. By contrast, gonadal expression of Spi3C/Serpinb6c was sexually dimorphic and restricted to male germ cells and female somatic cells. These observations raise the question of the possible role(s) of the Serpinb6 family members in gonad development, gametogenesis, and/or fertilization.

The mouse testis is the source of various serine proteases and serine proteinase inhibitors (SERPINs): Serine proteases and SERPINs identified in Leydig cells are under gonadotropin regulation

The occurrence of various serine proteinases and serine proteinases inhibitors (SERPINs) was investigated by RT-PCR in whole testes of 1-, 3-, and 8-wk-old mice in crude and enriched germ cell fractions, mouse Leydig tumor cells (mLTC-1), and primary cultures of 3- and 8-wk-old enriched fractions of Leydig cells and 3-wk-old Sertoli cells. New members were identified in the testis protease repertoire. Within the Leydig repertoire, a PCR product was found for plasminogen activators urokinase plasminogen activator (uPA) and tissue plasminogen activator (8-wk-old cells), matriptase-2 (mLTC-1), kallikrein-21, SERPINA5, SERPINB2 (primary cultures), and serine peptidase inhibitor Kunitz type 2 (SPINT2). The gonadotropin regulation was explored by semiquantitative RT-PCR, using steroidogenic acute regulatory protein (StAR) as a positive control. Matriptase-2, kallikrein-21, SPINT2, and SERPINA5 were down-regulated, whereas uPA and its receptor were up-regulated by human chorionic gonadotropin (hCG) via cAMP in the mLTC-1 cells. Positive effects were observed transiently after 1-8 h of hCG exposure, and negative effects, first evidenced after 6 h, lasted 48 h. The hCG-induced effects were confirmed in primary cultures. In addition, SERPINB2 was augmented by hCG in primary cultures. Addition of either trypsin or protease inhibitors did not alter the hCG-induced surge of StAR. Because hCG regulated proteases and SERPINs (whereas testosterone did not), it could alter the proteolytic balance of Leydig cells and consequently the metabolism of extracellular matrix components. Therefore, even though a direct interplay between the early hCG-induced surge of uPA and StAR is unlikely, our data together with the literature suggest that extracellular matrix proteins alter Leydig cell steroidogenesis.

Transferrin overexpression alters testicular function in aged mice

Many studies have shown a correlation between transferrin (Tf) concentration and sperm yield in several mammalian species. We have used transgenic mice expressing human Tf (hTf) to investigate if overexpression of Tf increases the efficiency of mouse spermatogenesis. We demonstrated that a 36% increase of Tf does not ameliorate the efficiency of mouse spermatogenesis but on the contrary resulted in a 36% decrease of testis sperm reserves. Tf overexpression had no effect on testicular determination and development, however testicular function of these transgenic mice was affected in an age-dependent manner. At 16 months of age, testicular and epididymal weights were significantly reduced. While spermatogenesis was qualitatively normal, testicular functions were perturbed. In fact, testosterone rate after human chorionic gonadotropin (hCG) stimulation was lower in Tf overexpressing mice. Intratesticular concentration of estradiol-17beta was increased and fluid accumulation after ligation of rete testis was more abundant in these transgenic mice. Surprisingly, we found that endogenous Tf levels were also increased in Tf overexpressing mice and we demonstrated for the first time that Tf may serve to upregulate its own expression in testis. Collectively, our data show that Tf overexpression has negative effects on testicular function and that Tf levels require strict regulation in the testis.

Characterization of recombinant human protein C inhibitor expressed in Escherichia coli

The serine protease inhibitor (serpin) protein C inhibitor (PCI; also named plasminogen activator inhibitor-3) regulates serine proteases in hemostasis, fibrinolysis, and reproduction. The biochemical activity of PCI is not fully defined partly due to the lack of a convenient expression system for active rPCI. Using pET-15b plasmid, Ni(2+)-chelate and heparin-Sepharose affinity chromatography steps, we describe here the expression, purification and characterization of wild-type recombinant (wt-rPCI) and two inactive mutants, R354A (P1 residue) and T341R (P14 residue), expressed in Escherichia coli. Wild-type rPCI, but not the two mutants, formed a stable bimolecular complex with thrombin, activated protein C and urokinase. In the absence of heparin, wt-rPCI-thrombin, -activated protein C, and -urokinase inhibition rates were 56.7, 3.4, and 2.3 x 10(4) M(-1) min(-1), respectively, and the inhibition rates were accelerated 25-, 71-, and 265-fold in the presence of 10 mug/mL heparin for each respective inhibition reaction. The stoichiometry of inhibition (SI) for wt-rPCI-thrombin was 2.0, which is comparable to plasma-derived PCI. The present report describes for the first time the expression and characterization of recombinant PCI in a bacterial expression system and demonstrates the feasibility of using this system to obtain adequate amounts of biologically active rPCI for future structure-function studies.

Basal membrane remodeling during follicle histogenesis in the rat ovary: contribution of proteinases of the MMP and PA families

In mammalian females, follicular units arise from the fragmentation of ovigerous cords, which spread over the first three postnatal days in the rat. The mechanisms underlying such a process of epithelial remodeling involve a specific balance between basal membrane (BM) deposition and degradation that has as yet not been precisely described. We have investigated the contribution of proteases in BM remodeling by localization of transcripts, protein, or enzymatic activity. In addition, we have analyzed BM deposition at the ultrastructural level and by immunofluorescence detection of BM components. At birth, when fragmentation occurred, epithelial cells displayed an upregulation of membrane type 1-matrix metalloproteinase (MT1-MMP) and urokinase-type plasminogen activator (uPA), as well as laminin alpha1 mRNAs. Although MMP2 expression was restricted to mesenchymal cells throughout development, in situ zymography showed that gelatinase-MMP2 activity colocalized with BM deposition inside deepening clefts in the areas of ovigerous cord fragmentation. In the days following birth, gelatin and plasminogen-casein zymography showed an increased enzymatic activity of MMP2 and uPA, respectively. In organotypic cultures of 21-day postconception ovaries, serine protease inhibitors like aprotinin could efficiently block follicle histogenesis. In addition, our results show that the well described and great wave of oocyte attrition characteristic of the days following birth closely correlates with BM remodeling. Altogether, our data show that during follicle histogenesis, ovigerous cord fragmentation results from an acute BM component deposition in deepening clefts and that BM homeostasy involves proteinases of the MMP2/MT1-MMP/TIMP3 and plasminogen/uPA families.

The Blood‐Testis Barrier: Its Biology, Regulation, and Physiological Role in Spermatogenesis

The blood-testis barrier (BTB) in mammals, such as rats, is composed of the tight junction (TJ), the basal ectoplasmic specialization (basal ES), the basal tubulobulbar complex (basal TBC) (both are testis-specific actin-based adherens junction [AJ] types), and the desmosome-like junction that are present side-by-side in the seminiferous epithelium. The BTB physically divides the seminiferous epithelium into basal and apical (or adluminal) compartments, and is pivotal to spermatogenesis. Besides its function as an immunological barrier to segregate the postmeiotic germ-cell antigens from the systemic circulation, it creates a unique microenvironment for germ-cell development and confers cell polarity. During spermatogenesis, the BTB in rodents must physically disassemble to permit the passage of preleptotene and leptotene spermatocytes. This occurs at late stage VII through early stage VIII of the epithelial cycle. Studies have shown that this dynamic BTB restructuring to facilitate germ-cell migration is regulated by two cytokines, namely transforming growth factor-beta3 (TGF-beta3) and tumor necrosis factor-alpha (TNFalpha), via downstream mitogen-activated protein kinases. These cytokines determine the homeostasis of TJ- and basal ES-structural proteins, proteases, protease inhibitors, and other extracellular matrix (ECM) proteins (e.g., collagen) in the seminiferous epithelium. Some of these molecules are known regulators of focal contacts between the ECM and other actively migrating cells, such as macrophages, fibroblasts, or malignant cells. These findings also illustrate that cell-cell junction restructuring at the BTB is regulated by mechanisms involved in the junction turnover at the cell-matrix interface. This review critically discusses these latest findings in the field in light of their significance in the biology and regulation of the BTB pertinent to spermatogenesis.

Diethylstilbestrol inhibits the expression of the steroidogenic acute regulatory protein in mouse fetal testis

This study investigated the early deleterious effects of an in-utero exposure to diethylstilbestrol (DES) on mouse testicular development. To that purpose, pregnant mice were injected daily with up to 100 microg/kg DES from 10.5 to 17.5 days postcoitum (dpc). At 18.5 dpc, testes were removed from fetuses for RNA (RT-PCR) and protein (Western blot, immunohistochemistry) analysis. Twenty-two genes were selected among which transcription factors, markers of differentiation of the different testicular cell lineages, steroidogenic enzymes and hormone receptors. The Steroidogenic Acute Regulatory (StAR) protein produced by the fetal Leydig cells was dramatically reduced in the DES-exposed testes. The P450c17 was the other gene modified following DES exposure. The alteration of these two genes is consistent with the decrease observed in the intratesticular testosterone levels, in the DES-exposed testes. Collectively, we demonstrated that DES did not alter testicular cell lineage specification but that it strongly inhibited the major function of the fetal Leydig cells.