Matrix metalloproteinases and tissue inhibitors of metalloproteinases in human fetal testis and ovary

Molecular mechanisms of cellular dysfunction in testes from men with non-obstructive azoospermia

Male factor infertility affects 50% of infertile couples worldwide; the most severe form, non-obstructive azoospermia (NOA), affects 10-15% of infertile males. Treatment for individuals with NOA is limited to microsurgical sperm extraction paired with in vitro fertilization intracytoplasmic sperm injection. Unfortunately, spermatozoa are only retrieved in ~50% of patients, resulting in live birth rates of 21-46%. Regenerative therapies could provide a solution; however, understanding the cell-type-specific mechanisms of cellular dysfunction is a fundamental necessity to develop precision medicine strategies that could overcome these abnormalities and promote regeneration of spermatogenesis. A number of mechanisms of cellular dysfunction have been elucidated in NOA testicular cells. These mechanisms include abnormalities in both somatic cells and germ cells in NOA testes, such as somatic cell immaturity, aberrant growth factor signalling, increased inflammation, increased apoptosis and abnormal extracellular matrix regulation. Future cell-type-specific investigations in identifying modulators of cellular transcription and translation will be key to understanding upstream dysregulation, and these studies will require development of in vitro models to functionally interrogate spermatogenic niche dysfunction in both somatic and germ cells.

Integrated Multi-Tissue Transcriptome Profiling Characterizes the Genetic Basis and Biomarkers Affecting Reproduction in Sheep (Ovis aries)

The heritability of litter size in sheep is low and controlled by multiple genes, but the research on its related genes is not sufficient. Here, to explore the expression pattern of multi-tissue genes in Chinese native sheep, we selected 10 tissues of the three adult ewes with the highest estimated breeding value in the early study of the prolific Xinggao sheep population. The global gene expression analysis showed that the ovary, uterus, and hypothalamus expressed the most genes. Using the Uniform Manifold Approximation and Projection (UMAP) cluster analysis, these samples were clustered into eight clusters. The functional enrichment analysis showed that the genes expressed in the spleen, uterus, and ovary were significantly enriched in the Ataxia Telangiectasia Mutated Protein (ATM) signaling pathway, and most genes in the liver, spleen, and ovary were enriched in the immune response pathway. Moreover, we focus on the expression genes of the hypothalamic-pituitary-ovarian axis (HPO) and found that 11,016 genes were co-expressed in the three tissues, and different tissues have different functions, but the oxytocin signaling pathway was widely enriched. To further explore the differences in the expression genes (DEGs) of HPO in different sheep breeds, we downloaded the transcriptome data in the public data, and the analysis of DEGs (Xinggao sheep vs. Sunite sheep in Hypothalamus, Xinggao sheep vs. Sunite sheep in Pituitary, and Xinggao sheep vs. Suffolk sheep in Ovary) revealed the neuroactive ligand-receptor interactions. In addition, the gene subsets of the transcription factors (TFs) of DEGs were identified. The results suggest that 51 TF genes and the homeobox TF may play an important role in transcriptional variation across the HPO. Altogether, our study provided the first fundamental resource to investigate the physiological functions and regulation mechanisms in sheep. This important data contributes to improving our understanding of the reproductive biology of sheep and isolating effecting molecular markers that can be used for genetic selection in sheep.

Metzincin metalloproteases in PGC migration and gonadal sex conversion

Development of a functional gonad includes migration of primordial germ cells (PGCs), differentiations of somatic and germ cells, formation of primary follicles or spermatogenic cysts with somatic gonadal cells, development and maturation of gametes, and subsequent releasing of mature germ cells. These processes require extensive cellular and tissue remodeling, as well as broad alterations of the surrounding extracellular matrix (ECM). Metalloproteases, including MMPs (matrix metalloproteases), ADAMs (a disintegrin and metalloproteinases), and ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs), are suggested to have critical roles in the remodeling of the ECM during gonad development. However, few research articles and reviews are available on the functions and mechanisms of metalloproteases in remodeling gonadal ECM, gonadal development, or gonadal differentiation. Moreover, most studies focused on the roles of transcription and growth factors in early gonad development and primary sex determination, leaving a significant knowledge gap on how differentially expressed metalloproteases exert effects on the ECM, cell migration, development, and survival of germ cells during the development and differentiation of ovaries or testes. We will review gonad development with focus on the evidence of metalloprotease involvements, and with an emphasis on zebrafish as a model for studying gonadal sex differentiation and metalloprotease functions.

Understanding the Underlying Molecular Mechanisms of Meiotic Arrest during In Vitro Spermatogenesis in Rat Prepubertal Testicular Tissue

In vitro spermatogenesis appears to be a promising approach to restore the fertility of childhood cancer survivors. The rat model has proven to be challenging, since germ cell maturation is arrested in organotypic cultures. Here, we report that, despite a meiotic entry, abnormal synaptonemal complexes were found in spermatocytes, and in vitro matured rat prepubertal testicular tissues displayed an immature phenotype. RNA-sequencing analyses highlighted up to 600 differentially expressed genes between in vitro and in vivo conditions, including genes involved in blood-testis barrier (BTB) formation and steroidogenesis. BTB integrity, the expression of two steroidogenic enzymes, and androgen receptors were indeed altered in vitro. Moreover, most of the top 10 predicted upstream regulators of deregulated genes were involved in inflammatory processes or immune cell recruitment. However, none of the three anti-inflammatory molecules tested in this study promoted meiotic progression. By analysing for the first time in vitro matured rat prepubertal testicular tissues at the molecular level, we uncovered the deregulation of several genes and revealed that defective BTB function, altered steroidogenic pathway, and probably inflammation, could be at the origin of meiotic arrest.

UHRF1 establishes crosstalk between somatic and germ cells in male reproduction

Sertoli cells (SCs) support and nourish germ cells (GCs) through their crosstalk during spermatogenesis. However, the underlying epigenetic mechanism that ensures SCs’ functions in this process remains unclear. Here, we report that UHRF1, a critical epigenetic regulator, is mainly expressed in human and mouse pre-mature SCs, and is essential for establishing Sertoli-Germ cell crosstalk. SC-specific UHRF1 knockout mice exhibit complete sterility with Sertoli cell (SC) proliferation and differentiation aberrance, blood-testis barrier (BTB) disruption, and immature germ cell (GC) sloughing. RNA sequencing and Whole Genome Bisulfite Sequencing (WGBS) revealed that many extracellular matrix (ECM)-related genes (e.g., Timp1, Trf, and Spp1) appeared upregulated with the DNA hypomethylation status in UHRF1-deficient SCs. Strikingly, overexpression of Timp1, Trf, and Spp1 in SCs in vitro and in vivo could phenocopy the SC-specific UHRF1-deficient mice. Our data demonstrated that UHRF1 regulates the transcriptional program of ECM-related genes in SCs and establishes SC-GC crosstalk.

Metalloproteases in gonad formation and ovulation

Changes in expression or activation of various metalloproteases including matrix metalloproteases (Mmp), a disintegrin and metalloprotease (Adam) and a disintegrin and metalloprotease with thrombospondin motif (Adamts), and their endogenous inhibitors (tissue inhibitors of metalloproteases, Timp), have been shown to be critical for ovulation in various species from studies in past decades. Some of these metalloproteases such as Adamts1, Adamts9, Mmp2, and Mmp9 have also been shown to be regulated by luteinizing hormone (LH) and/or progestin, which are essential triggers for ovulation in all vertebrate species. Most of these metalloproteases also express broadly in various tissues and cells including germ cells and somatic gonad cells. Thus, metalloproteases likely play roles in gonad formation processes comprising primordial germ cell (PGC) migration, development of germ and somatic cells, and sex determination. However, our knowledge on the functions and mechanisms of metalloproteases in these processes in vertebrates is still lacking. This review will summarize our current knowledge on the metalloproteases in ovulation and gonad formation with emphasis on PGC migration and germ cell development.

Matrix metalloproteinase (MMP)-2, MMP-9, semen quality and sperm longevity in fractionated stallion semen

Matrix metalloproteinase (MMP)-2 and MMP-9 are gelatinases that take part in several reproductive processes. The aim of this study was to measure levels of MMP-2 and MMP-9 in fractionated stallion ejaculates, and to evaluate the association between these components and semen quality, and sperm longevity during cooled storage. Semen quality were assessed separately for sperm-rich fractions (HIGH), sperm-poor fractions (LOW), and whole ejaculate samples (WE) from 33 stallions. After cooled storage with SP either present or removed, sperm motility and DFI were determined. The relative activity of the pro-form of MMP-2, active MMP-2 and total MMP-9 were evaluated using gelatin zymography, and all were present in all fractions of the stallion's ejaculate, with higher relative activity of the latent than active forms and the highest relative activity in the HIGH fraction. The relative activities of MMP-2 and MMP-9 were positively correlated to sperm concentration and total sperm count, but only in the HIGH fraction and not in LOW or WE. The relative activities of MMPs were not related to differences in sperm longevity during cooled storage, measured as sperm motility and DFI. There was a harmful effect of SP on DFI during storage, but this effect was not associated with differences in the relative activities of MMPs. In conclusion, the relative activities of MMPs are not useful as markers for semen quality (other than sperm concentration), or sperm survival during storage in horses.

The effects of CoQ10 supplement on matrix metalloproteinases, oxidative DNA damage and pro-inflammatory cytokines in testicular ischaemia/reperfusion injury in rats

We aimed to study the effect of coenzyme Q10 on pro-inflammatory cytokine, matrix metalloproteinase, oxidative DNA damage, caspase 3 and caspase 8 in ischaemia/reperfusion injury led to by testicular torsion/detorsion. Our research is a controlled experimental animal research using rats. This study was conducted with fifty-six adult male Albino Wistar rats. Interleucine-1β, 2, 6, 10, tumour necrosis factor-α, matrix metalloproteinase-2, 3, 9, 13, tissue inhibitor matrix metalloproteinase-1, 2, malondialdehyde and leucocyte 8-hydroxy-2-deoxy guanosine/10⁶ deoxyguanosine was detected in serum and tissue samples. In addition, immunohistochemical analysis of caspase 2 and caspase 8 was performed. In testicular I/R injury, especially 24 hr after detorsion, oxidative damage pro-inflammatory cytokines and matrix metalloproteinases were increased. At the coenzyme Q10 group, a meaningful decrease was observed in these parameters. In addition, a decrease in the expression of caspase3 and caspase 8 was viewed in coenzyme Q10-treated groups. The coenzyme Q10 has beneficial effects on oxidative damage, pro-inflammatory cytokine levels, remodelling of extracellular matrix and apoptosis in testicular I/R injury.

Morinda Officinalis Polysaccharides Attenuate Varicocele-Induced Spermatogenic Impairment through the Modulation of Angiogenesis and Relative Factors

Evidence supporting best treatment practices for varicocele is lacking. The effects of a water-soluble polysaccharide extracted from Morinda officinalis (MOP) on the progression of varicocele were evaluated in the present study. The extracted MOP was confirmed as having a high purity of 98% with scant protein contamination, and it mainly consisted of glucose, lactose, and xylose at a molar ratio of 7.63:1.23:0.95 glucose:lactose:xylose. MOPs were administered to experimental left varicocele rats immediately after surgery at doses ranging from 25 to 200 mg/kg. As detected by sperm analysis and histopathological staining, the intragastric administration of 100 mg/kg MOPs significantly improved the sperm parameters of bilateral cauda epididymis, attenuated seminiferous epithelial structures, and inhibited germ cell apoptosis. The results of immunofluorescence and immunoblot showed that administration of 100 mg/kg MOPs effectively inhibited angiogenesis in the bilateral testes but modulated the expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase 2 (MMP2), and MMP9 mildly. These results indicate that inhibition of angiogenesis may be one of the mechanisms by which MOP exerts its inhibitive activities on the progression of varicocele, whereas a relative upregulation of VEGF and MMP-9 may be crucial for the spermatogenetic protective effects of 100 mg/kg MOP administration.

Association between tissue inhibitor of metalloproteinase (TIMP) genetic polymorphisms and primary ovarian insufficiency (POI)

BACKGROUND

Until now, an association between tissue inhibitor of metalloproteinase (TIMP) polymorphisms and primary ovarian insufficiency (POI) has not been identified. The aim of our study was to investigate whether the TIMP polymorphisms TIMP1T > C (rs4898), TIMP1G > A (rs6609533), TIMP2G > C (rs8179090), TIMP2G > A (rs2277698), TIMP3G > A (rs135029), and TIMP4T > C (rs3755724), which regulate matrix metalloproteinases (MMPs), confer a risk for primary ovarian insufficiency (POI) in Korean women (further studies would be required to evaluate the associations between TIMP polymorphisms and POI in other populations).

METHODS

We genotyped 137 POI patients and 236 controls for the single nucleotide polymorphism sites using PCR-RFLP analysis. Differences in the frequencies of the TIMP1T > C (rs4898), TIMP1G > A (rs6609533), TIMP2G > C (rs8179090), TIMP2G > A (rs2277698), TIMP3G > A (rs135029), and TIMP4T > C (rs3755724) genotypes between patients and controls were compared, and odds ratios and 95% confidence intervals were determined to measure of the strength of the association between the genotypes and POI.

RESULTS

The TIMP1T > C (rs4898), TIMP1G > A (rs6609533), TIMP2G > C (rs8179090), TIMP2G > A (rs2277698), TIMP3G > A (rs135029), and TIMP4T > C (rs3755724) genotypes, but especially the TIMP2 genotypes, were found more frequently in POI patients than in control subjects. Among the four TIMP loci, the TIMP1T > C (rs4898), TIMP1G > A (rs6609533), TIMP2G > C (rs8179090), TIMP2G > A (rs2277698), TIMP3G > A (rs135029), and TIMP4T > C (rs3755724) haplotypes were identified more frequently in POI patients than in control subjects and conferred susceptibility to POI (P <0.0001).

CONCLUSIONS

The TIMP2G > C (rs8179090) and G > A (rs2277698) alleles were strongly associated with POI. Our data suggest that the minor TIMP2 alleles may increase POI risk in Korean women.

Semen levels of matrix metalloproteinase (MMP) and tissue inhibitor of metallorproteinases (TIMP) protein families members in men with high and low sperm DNA fragmentation

Matrix Metalloproteinases (MMPs) and their regulators – Tissue Inhibitors of Matrix Metalloproteinases (TIMPs) – participate in extracellular matrix remodeling, fibrosis, and semen liquefaction, as well as to inflammatory activity. Seminal plasma has been shown to contain MMPs (MMP-2 and MMP-9) and TIMPs (TIMP-1 and TIMP-2). Also, a link between MMPs gene expression and excessive reactive oxygen species (ROS) has been established. In semen, ROS are associated with altered sperm function and increased DNA fragmentation. In this study, it is hypothesized that seminal MMPs and TIMPs levels are associated with sperm DNA fragmentation due to the fact that MMPs have been associated with semen quality. We also hypothesized that these proteins could predict DNA fragmentation status in sperm. Therefore, this study set out to verify if sperm DNA fragmentation levels relate to seminal levels of members of the MMP and TIMP protein families. The High sperm DNA fragmentation group presented lower seminal plasma levels of MMP-2, MMP-7, TIMP-1, TIMP-2 and TIMP-4 when compared to Low sperm DNA fragmentation group. Also, samples in the high sperm DNA fragmentation group presented higher acrosome integrity and lower mitochondrial activity levels when compared to low sperm DNA fragmentation samples. In the logistic regression analysis, MMP-2, MMP-7, and TIMP-4 classified samples as low and high sperm DNA fragmentation, with an overall model fit of 74.5%. Results from this study may demonstrate a specific inflammatory mechanism in samples with high sperm DNA fragmentation. This, in turn, can lead to the development of new studies regarding this mechanism and, in the future, create an opportunity to treat these patients for sperm DNA fragmentation by treating inflammatory seminal activity.

Prostaglandin F2α stimulates adhesion, migration, invasion and proliferation of the human trophoblast cell line HTR-8/SVneo

INTRODUCTION

The amount of prostaglandin F_2α (PGF_2α) in the uterine lumen increases during the window of implantation in many mammals, including humans. We hypothesized that PGF_2α regulates processes related to human embryo implantation.

METHODS

The effect of PGF_2α was studied using an in vitro model of human extravillous trophoblast (EVT) cell line (HTR-8/SVneo). Adhesion, proliferation, invasion and migration assays, zymography for metalloproteinases (MMP) activity, and gene/protein expression analyses were applied. Doses of 100 nM and/or 1 μM of PGF_2α and fluprostenol were used. PGF_2α receptor (PTGFR), MMP9 and MMP2 proteins in the human first trimester placenta were localized by immunohistochemistry and immunofluorescence.

RESULTS

This study is the first reporting the expression of PTGFR protein in the first trimester placenta, as well as in HTR-8/SVneo cells. PGF_2α and fluprostenol increased HTR-8/SVneo cell proliferation and adhesion to extracellular matrix protein (P < 0.05). This effect was abolished by mitogen activated protein kinases (MAPK) inhibitor. PGF_2α induced phosphorylation of focal adhesion kinase and MAPK1/3 (P < 0.05). PGF_2α increased mRNA content and protein activity of MMP9, and gene and protein expression of interleukin-6 (P < 0.05). EVT cell migration and invasiveness were stimulated by PGF_2α (P < 0.05). The PGF_2α effect on cell invasion was reduced by inhibitors of MMP2, MMP9 and mTOR. In all experiments, the stimulatory effects of PGF_2α were diminished by using a PTGFR antagonist.

DISCUSSION

Our findings suggest a significant role for PGF_2α in mechanisms associated with implantation. PGF_2α acting by PTGFR in HTR-8/SVneo cells stimulates their adhesion and proliferation through the MAPK signaling pathway and increases invasiveness inducing MMP proteolytic activity and mTOR signaling.

Association between estrogen receptor 1 (ESR1) and leukemia inhibitory factor (LIF) polymorphisms can help in the prediction of recurrent implantation failure

OBJECTIVE

To investigate an association between polymorphisms related to the implantation process that together could help in the prediction of recurrent implantation failure (RIF).

DESIGN

Cohort study.

SETTING

Private fertility center and reproductive genetics laboratory.

PATIENT(S)

Forty-four women presenting RIF, who were included in study group (RIF group), and two control groups, one with 63 women who were attended at our service and became pregnant after the first IVF/intracytoplasmic sperm injection attempt (control group I) and other with 65 fertile women who had at least two children without any treatment and no history of miscarriage (control group II).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Genotyping was performed in the intron region of TP63, VEGFA, MMP2, ESR1, and ESR2 genes and in the 3' untranslated region of the LIF gene on genomic DNA using real-time polymerase chain reaction.

RESULT(S)

The presence of ESR1/AA (rs12199722) and LIF/GT (rs929271) genotypes was more frequent in the RIF group, leading to a 7.9-fold increase in the chance of women presenting with RIF when compared with women who became pregnant on their first cycle of IVF/intracytoplasmic sperm injection and a 2.8-fold increase when compared with women who became pregnant without treatment.

CONCLUSION(S)

The association between ESR1 and LIF polymorphisms can help in the prediction of RIF.

Activin A target genes are differentially expressed between normal and neoplastic adult human testes: clues to gonocyte fate choice

BACKGROUND

Human testicular germ cell tumours (TGCT) arise from germ cell neoplasia in situ (GCNIS) cells that originate from foetal germ cell precursors. Activin A is central to normal foetal testis development, and its dysregulation may contribute to TGCT aetiology.

OBJECTIVE

(i) To test whether the expression profiles of activin A targets in normal and neoplastic human testes indicates functional links with TGCT progression. (ii) To investigate whether activin A levels influence MMP activity in a neoplastic germ cell line.

MATERIALS AND METHODS

(1) Bouin's fixed, paraffin-embedded human testes were utilized for PCR-based transcript analysis and immunohistochemistry. Samples (n = 5 per group) contained the following: (i) normal spermatogenesis, (ii) GCNIS or (iii) seminoma. CXCL12, CCL17, MMP2 and MMP9 were investigated. (2) The human seminoma-derived TCam-2 cell line was exposed to activin A (24 h), and target transcripts were measured by qRT-PCR (n = 4). ELISA (n = 4) and gelatin zymography (n = 3) showed changes in protein level and enzyme activity, respectively.

RESULTS

(i) Cytoplasmic CXCL12 was detected in Sertoli and other somatic cells, including those surrounding seminoma cells. Anti-CCL17 labelled only the cytoplasm of Sertoli cells surrounding GCNIS, while anti-MMP2 and anti-MMP9 labelled germline and epithelial-like cells in normal and neoplastic testes. (ii) Exposing TCam-2 cells to activin A (50 ng/mL) elevated MMP2 and MMP9 transcripts (fourfold and 30-fold), while only MMP2 protein levels were significantly higher after activin A (5 ng/mL and 50 ng/mL) exposure. Importantly, gelatin zymography revealed activin A increased production of activated MMP2.

DISCUSSION

Detection of CCL17 only in GCNIS tumours may reflect a change in Sertoli cell phenotype to a less mature state. Stimulation of MMP2 activity by activin A in TCam-2 cells suggests activin influences TGCT by modulating the tumour niche.

CONCLUSION

This knowledge provides a basis for understanding how physiological changes that influence activin/TGF-β superfamily signalling may alter germ cell fate.

Long term impact of the endocrine disruptor tributyltin on male fertility following a single acute exposure

Declining rate of human fertility is a growing concern, where lifestyle and environmental factors play an important role. We recently demonstrated that tributyltin (TBT), an omnipresent endocrine disruptor, affects testicular cells in vitro. In this study, male Wistar rats were gavaged a single dose of 10, 20, and 30 mg/kg TBT-chloride (TBTC) (to mimic accidental exposure in vivo) and sacrificed on day 3 and day 7, respectively. TBT bioavailability was evaluated by estimating total tin content, and essential metal levels were analyzed along with redox molecules (ROS and GSH/GSSG) to understand the effect on physiological conditions. Blood-testicular barrier (BTB) disruption, levels of associated proteins and activity of proteolytic enzymes were evaluated to understand the effect on BTB. Histological analysis of tissue architecture and effect on protein expression of steroidogenic, stress and apoptotic markers were also evaluated. Widespread TBTC pollution can be an eventual threat to male fertility worldwide.

Original Article. Matrix Metalloproteinase Mmp-2 and Mmp-9 Activities in Seminal Plasma

Matrix metalloproteinases (MMPs) areagroup of proteases containing Zn ions asacofactor, which are involved in degrading ofalarge number of extracellular matrix proteins, and bioactive molecules. They also playamajor role in processes such as cell proliferation, cell migration, differentiation and apoptosis. Very little is known about the expression and function of MMPs in the male reproductive tract. Occurrence of MMP-2 and MMP-9 activity in human seminal plasma has been previously reported but their origin and function are still not fully understood. The aim of this study was to examine the presence of MMP-2 and MMP-9 in normal and abnormal human sperm samples and find if any correlation existed between the levels of expression of MMPs and fertilization potential of the spermatozoa. Human spermsamples were examined for the presence of MMP-2 and MMP-9 by gel zymography and western blot analysis. A DNAfragmentation test was performed. The samples were divided into two groups - samples with normozoospermia and teratozoospermia. The gelatin zymography showed gelatinolytic bands with molecular weight 64 and 72 k Da corresponding to active and inactive form of MMP-2. MMP-9 was not detected. The MMP-2 enzymatic activity appeared to be much higher in samples with compromised sperm morphology as compared to the normozoospermic samples. The mean DNAfragmentation index (DFI) of the group with teratozoospermia was relatively higher (22.16%) and over the upper reference limits, compared to the normozoospermic group, in which it was within the normal range (17.26%).

MMP2, MMP9 and TIMP2 polymorphisms affect sperm parameters but not fertility in Polish males

Proper function of the blood-testis barrier is pivotal to spermatogenesis. Synchronised action of matrix metalloproteinases (MMP) and their inhibitors (TIMP) is mandatory to maintain dynamic balance of the barrier. Therefore, the association of functional genetic variants of MMP-2, MMP-9 and TIMP-2 and male infertility was studied. A total of 416 infertile males and 421 healthy subjects were genotyped for 7 SNPs within MMP2, MMP9 and TIMP2 genes, along with the assessment of semen parameters (concentration, motility and morphology of spermatozoa). No association was observed between the studied genotypes and male infertility. However, higher sperm concentration was associated with TIMP2 rs8080623 C and rs2277698 T variants among infertile men, and with MMP9 rs17576 A minor allele in controls (p < .05). TIMP2 rs9900972 T and rs2277698 T allele were associated with higher percentage of morphologically normal spermatozoa among controls. MMP2 rs2285053 TT homozygous infertile patients presented higher percentage of spermatozoa displaying nonprogressive motility. Haplotype analysis revealed strong linkage disequilibrium between the studied loci (5 of 8 possible TIMP2 haplotypes, and 3 of 4 possible MMP2 and MMP9 were found). None of the haplotypes showed association with infertility. This study results suggest an association between MMP9 and TIMP2 SNPs with sperm parameters, but not infertility.

Mast cells, estrogens, and cryptorchidism: A histological based review

If untreated, cryptorchidism leads to age dependent decreases in germ cell number (GCN) and testicular fibrosis. The pathophysiology of this process and its long-term effects on fertility are unclear. Mast cells are intricately involved in inflammation and fibrosis in a variety of organ systems. Their secretory products have mitogenic effects on fibroblasts and promote collagen deposition. Mast cell activation and migration are under the influence of estrogens and this interaction has been demonstrated in the testes in several animal models. Models of cryptorchidism have shown increased estrogen levels and expression of estrogen receptors in undescended testes compared to controls. Mast cell numbers have positively correlated with testicular fibrosis in human studies and decreased spermatogenesis as well. We found no human studies of mast cells in cryptorchid testes. However several animal models have investigated the effect of estrogens on mast cells and spermatogenesis in undescended testes. In this review we examine the possible links between estrogens, mast cells, and testicular fibrosis in cryptorchidism, focusing on histological studies.

Identification of Putative Biomarkers for the Early Stage of Porcine Spermatogonial Stem Cells Using Next-Generation Sequencing

To identify putative biomarkers of porcine spermatogonial stem cells (pSSCs), total RNA sequencing (RNA-seq) analysis was performed on 5- and 180-day-old porcine testes and on pSSC colonies that were established under low temperature culture conditions as reported previously. In total, 10,184 genes were selected using Cufflink software, followed by a logarithm and quantile normalization of the pairwise scatter plot. The correlation rates of pSSCs compared to 5- and 180-day-old testes were 0.869 and 0.529, respectively and that between 5- and 180-day-old testes was 0.580. Hierarchical clustering data revealed that gene expression patterns of pSSCs were similar to 5-day-old testis. By applying a differential expression filter of four fold or greater, 607 genes were identified between pSSCs and 5-day-old testis, and 2118 genes were identified between the 5- and 180-day-old testes. Among these differentially expressed genes, 293 genes were upregulated and 314 genes were downregulated in the 5-day-old testis compared to pSSCs, and 1106 genes were upregulated and 1012 genes were downregulated in the 180-day-old testis compared to the 5-day-old testis. The following genes upregulated in pSSCs compared to 5-day-old testes were selected for additional analysis: matrix metallopeptidase 9 (MMP9), matrix metallopeptidase 1 (MMP1), glutathione peroxidase 1 (GPX1), chemokine receptor 1 (CCR1), insulin-like growth factor binding protein 3 (IGFBP3), CD14, CD209, and Kruppel-like factor 9 (KLF9). Expression levels of these genes were evaluated in pSSCs and in 5- and 180-day-old porcine testes. In addition, immunohistochemistry analysis confirmed their germ cell-specific expression in 5- and 180-day-old testes. These finding may not only be useful in facilitating the enrichment and sorting of porcine spermatogonia, but may also be useful in the study of the early stages of spermatogenic meiosis.

Thermal manipulation during embryogenesis improves certain semen parameters in layer breeder chicken during hot climatic conditions

Thermal manipulation during incubation has been shown to improve post hatch performance in poultry. The aim of the present experiment was to evaluate thermal manipulation on semen quality of roosters during hot climatic conditions. Eggs obtained after artificial insemination from Dahlem Red layer breeders were randomly divided into two groups control (C) and heat exposed (HE). C group eggs were incubated at 37.5°C throughout the incubation period while the HE group eggs were exposed to higher temperature 40.5°C from 15th to 17th day of incubation for 3h each day. The relative humidity was maintained at 65% in both the groups throughout incubation. The chicks hatched were reared separately under standard husbandry conditions. During high ambient temperature semen from roosters (45 weeks of age) was collected and evaluated for different gross parameters, sperm chromatin integrity and sperm HSP27 and HSP70 gene expression by real-time PCR. The seminal plasma was evaluated for lipid peroxidation, ferric ion reducing antioxidant power (FRAP), triiodothyronine (T3) and matrix metalloproteinase-2 (MMP-2) activity. The shed average Temperature Humidity Index (THI) during the experiment period was 78.55. The percent live sperm and FRAP level were significantly (P<0.05) higher and sperm gene expressions were significantly (P<0.05) lower in the HE group. No differences in other parameters were observed between the groups. Thus from the results it could be concluded that thermal manipulation during incubation improves certain semen parameters of roosters at high ambient temperature.

Molecular characterization and hormonal regulation of tissue inhibitor of metalloproteinase 1 in goat ovarian granulosa cells

Tissue inhibitor of metalloproteinase 1 (TIMP1) belongs to a group of endogenous inhibitors that control the activity of matrix metalloproteinases and other metalloproteinases. TIMP1 is ubiquitously expressed and implicated in many physiological and pathologic processes. In this study, the full-length complementary DNA of goat (Capra hircus) Timp1 was cloned from adult goat ovary for the first time to better understand the regulatory role of TIMP1. The putative TIMP1 protein shared a high amino acid sequence identity with other species. Real-time polymerase chain reaction results showed that Timp1 was widely expressed in adult goat tissues, and messenger RNA expression was higher in the ovary than in other tissues; meanwhile, increasing expression of Timp1 was also discovered during the process of follicle growth and corpus luteum. We then investigated Timp1 expression patterns in different types of ovarian follicular cells from goats. In small or large antral follicles, Timp1 expression was higher (P < 0.05) in theca cells than in granulosa cells, cumulus cells, and oocytes. Increasing expression of Timp1 in theca and granulosa cells was observed as the variation of the follicle size. Immunohistochemical analyses further revealed the presence of the TIMP1 proteins in follicles at all antral stages of development. The most intense staining for TIMP1 was observed in the theca cells and granulosa cells of large antral follicles and corpus luteum. Timp1 was highly (P < 0.05) induced in granulosa cells in vitro after treatment with the luteinizing hormone agonist, human chorionic gonadotropin. Treatments with forskolin, phorbol 12-myristate 13-acetate, or phorbol 12-myristate 13-acetate + forskolin could also stimulate Timp1 messenger RNA expression. The effects of human chorionic gonadotropin were reduced (P < 0.05) by the inhibitors of protein kinase A, protein kinase C, MAPK kinase, or p38 kinase, indicating that Timp1 expression could be adjusted by luteinizing hormone-initiated activation of these signaling mediators. Our results suggested that TIMP1 may be involved in regulating ovarian follicle development and ovulation.

Expression of matrix metalloproteinases (MMP-2, MMP-9) and their inhibitors (TIMP-1, TIMP-2) in canine testis, epididymis and semen

This study aims to investigate the role of matrix metalloproteinases (MMPs) in determining semen quality and to evaluate the expression and cellular localization of MMP-2, MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2 in the testes, epididymis and ejaculated spermatozoa. Gelatinase activities between normal (n = 21) and abnormal (n = 25) semen samples showed a significant, sixfold increase in proMMP-2 and MMP-2 activity in high than low sperm concentration samples (p < 0.001). ProMMP-9 and MMP-9 levels were significantly elevated in samples with low sperm counts compared to those with high sperm density (p < 0.001). High levels of proMMP-2 and MMP-2 were associated with high sperm motility (≥70%, p < 0.001). Sperm-rich fraction showed significantly (eight-fold) higher proMMP-9 enzymatic activity compared with prostatic fraction. The mRNA expressions of MMP-2, MMP-9, TIMP-1 and TIMP-2 were confirmed in testicular and epididymal tissues. Immunohistochemical staining illustrated the MMP-2-specific strong immunoreactivity in the head of mature spermatids during spermatogenesis, whereas MMP-9, TIMP-1 and TIMP-2 were absent in these cells. Matrix metalloproteinase-9 immunoreactivity was observed in the spermatocyte and round spermatid, whereas TIMP-1 was only exhibited in the residual bodies. Immunolabeling of epididymal and ejaculated sperm demonstrated MMP-2 localization along acrosomal region of sperm, while MMP-9, TIMP-1 and TIMP-2 localization was merely limited to the flagella. In conclusion, spermatozoa initially acquire MMP-2 during their formation at testicular level, and the presence of this protein persists through the epididymal transit and up to ejaculate. The enzymatic activity of MMP-2 and MMP-9 may serve as an alternative biomarker in determining semen quality.

Genetic removal of matrix metalloproteinase 9 rescues the symptoms of fragile X syndrome in a mouse model

Fmr1 knock-out (ko) mice display key features of fragile X syndrome (FXS), including delayed dendritic spine maturation and FXS-associated behaviors, such as poor socialization, obsessive-compulsive behavior, and hyperactivity. Here we provide conclusive evidence that matrix metalloproteinase-9 (MMP-9) is necessary to the development of FXS-associated defects in Fmr1 ko mice. Genetic disruption of Mmp-9 rescued key aspects of Fmr1 deficiency, including dendritic spine abnormalities, abnormal mGluR5-dependent LTD, as well as aberrant behaviors in open field and social novelty tests. Remarkably, MMP-9 deficiency also corrected non-neural features of Fmr1 deficiency-specifically macroorchidism-indicating that MMP-9 dysregulation contributes to FXS-associated abnormalities outside the CNS. Further, MMP-9 deficiency suppressed elevations of Akt, mammalian target of rapamycin, and eukaryotic translation initiation factor 4E phosphorylation seen in Fmr1 ko mice, which are also associated with other autistic spectrum disorders. These findings establish that MMP-9 is critical to the mechanisms responsible for neural and non-neural aspects of the FXS phenotype.

Effects of hormones on the expression of matrix metalloproteinases and their inhibitors in bovine spermatozoa

Proteases and protease inhibitors play key roles in most physiological processes, including cell migration, cell signaling, and cell surface and tissue remodeling. Among these, the matrix metalloproteinase (MMPs) pathway is one of the most efficient biosynthetic pathways for controlling the activation of enzymes responsible for protein degradation. This also indicates the association of MMPs with the maturation of spermatozoa. In an attempt to investigate the effect of MMP activation and inhibitors in cultures with various hormones during sperm capacitation, we examined and monitored the localization and expression of MMPs (MMP-2 and MMP-9), tissue inhibitors of metalloproteinases (TIMP-2 and TIMP-3), as well as their expression profiles. Matured spermatozoa were collected from cultures with follicle-stimulating hormone (FSH), luteinizing hormone (LH), and Lutalyse at 1 h, 6 h, 18 h, and 24 h. ELISA detected the expression of MMP-2, MMP-9, TIMP-2, and TIMP-3 in all culture media, regardless of medium type (FSH-supplemented fertilization Brackett-Oliphant medium (FFBO), LH-supplemented FBO (LFBO), or Lutalyse-supplemented FBO (LuFBO)). TIMP-2 and TIMP-3 expression patterns decreased in LFBO and LuFBO. MMP-2 and MMP-9 activity in FBO and FFBO progressively increased from 1 h to 24 h but was not detected in LFBO and LuFBO. The localization and expression of TIMP-2 and TIMP-3 in sperm heads was also measured by immunofluorescence analysis. However, MMPs were not detected in the sperm heads. MMP and TIMP expression patterns differed according to the effect of various hormones. These findings suggest that MMPs have a role in sperm viability during capacitation. In conjunction with hormones, MMPs play a role in maintaining capacitation and fertilization by controlling extracellular matrix inhibitors of sperm.

TAp73 is essential for germ cell adhesion and maturation in testis

The p53 family member TAp73 is required for sperm maturation through promotion of adhesion between developing germ cells and Sertoli nurse cells.

A core evolutionary function of the p53 family is to protect the genomic integrity of gametes. However, the role of p73 in the male germ line is unknown. Here, we reveal that TAp73 unexpectedly functions as an adhesion and maturation factor of the seminiferous epithelium orchestrating spermiogenesis. TAp73 knockout (TAp73KO) and p73KO mice, but not ΔNp73KO mice, display a “near-empty seminiferous tubule” phenotype due to massive premature loss of immature germ cells. The cellular basis of this phenotype is defective cell–cell adhesions of developing germ cells to Sertoli nurse cells, with likely secondary degeneration of Sertoli cells, including the blood–testis barrier, which leads to disruption of the adhesive integrity and maturation of the germ epithelium. At the molecular level, TAp73, which is produced in germ cells, controls a coordinated transcriptional program of adhesion- and migration-related proteins including peptidase inhibitors, proteases, receptors, and integrins required for germ–Sertoli cell adhesion and dynamic junctional restructuring. Thus, we propose the testis as a unique organ with strict division of labor among all family members: p63 and p53 safeguard germ line fidelity, whereas TAp73 ensures fertility by enabling sperm maturation.

Ovarian and uterine characteristics and onset of puberty in adolescent offspring: effects of maternal diet and selenium supplementation in sheep

The aim of this study was to determine the effects of maternal diet with adequate (A) or high (H) selenium (Se) supplementation on ovarian and uterine characteristics, and onset of puberty in adolescent offspring. Sheep were fed a maintenance (M) diet with ASe or HSe levels from breeding to parturition. From Day 50 to parturition, a portion of the ewes from ASe and HSe groups was fed restricted (R, 60% of M) or excess (E, 140% of M) diet. Immediately after birth, lambs were separated from their dams and given artificial colostrum for 20 hours, followed by milk replacer. From Day 57.3 ± 0.6, ewe lambs were fed a pelleted grower diet until Day 116.3 ± 0.6 when they were transitioned to a finisher diet. From Day 99 to 180, serum samples were collected weekly from jugular vein for progesterone analysis to determine onset of puberty. Reproductive tissues were collected on Day 180.1 ± 0.4 of age. Maternal diet or Se supplementation did not affect uterine or ovarian weight and onset of puberty. However, area under the curve for progesterone was greater (P = 0.05) in ASe compared with HSe groups, and was greater in ASeM than HSeM group. In CLs, labeling index (LI; a proportion of proliferating cells) was less (P < 0.04) in HSeM than ASeM group, and in stroma was less (P < 0.05) in R and E groups than M group. Maternal diet did not affect the LI of any follicle types. For all groups combined, LI was the greatest (P < 0.001) in antral, less in early antral and secondary, and the least in atretic follicles. Our results demonstrate that maternal diet influenced ovarian but not uterine characteristics or onset of puberty. These results indicate that maternal plane of nutrition and/or Se supplementation may have specific effects on reproductive function in offspring.

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.

TIMPs of parasitic helminths - a large-scale analysis of high-throughput sequence datasets

BACKGROUND

Tissue inhibitors of metalloproteases (TIMPs) are a multifunctional family of proteins that orchestrate extracellular matrix turnover, tissue remodelling and other cellular processes. In parasitic helminths, such as hookworms, TIMPs have been proposed to play key roles in the host-parasite interplay, including invasion of and establishment in the vertebrate animal hosts. Currently, knowledge of helminth TIMPs is limited to a small number of studies on canine hookworms, whereas no information is available on the occurrence of TIMPs in other parasitic helminths causing neglected diseases.

METHODS

In the present study, we conducted a large-scale investigation of TIMP proteins of a range of neglected human parasites including the hookworm Necator americanus, the roundworm Ascaris suum, the liver flukes Clonorchis sinensis and Opisthorchis viverrini, as well as the schistosome blood flukes. This entailed mining available transcriptomic and/or genomic sequence datasets for the presence of homologues of known TIMPs, predicting secondary structures of defined protein sequences, systematic phylogenetic analyses and assessment of differential expression of genes encoding putative TIMPs in the developmental stages of A. suum, N. americanus and Schistosoma haematobium which infect the mammalian hosts.

RESULTS

A total of 15 protein sequences with high homology to known eukaryotic TIMPs were predicted from the complement of sequence data available for parasitic helminths and subjected to in-depth bioinformatic analyses.

CONCLUSIONS

Supported by the availability of gene manipulation technologies such as RNA interference and/or transgenesis, this work provides a basis for future functional explorations of helminth TIMPs and, in particular, of their role/s in fundamental biological pathways linked to long-term establishment in the vertebrate hosts, with a view towards the development of novel approaches for the control of neglected helminthiases.

Impact of micronised purified flavonoid fraction on increased malondialdehyde and decreased metalloproteinase-2 and metalloproteinase-9 levels in varicocele: outcome of an experimentally induced varicocele

To analyse the levels of an indirect marker of ROS-induced lipid peroxidation [i.e. malondialdehyde (MDA)] in both testes and the levels of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) and matrix metalloproteinase inhibitor-1 (TIMP-1) in the left testis after induction of varicocele and investigated the impact of micronised purified flavonoid fraction (MPFF) on these markers. Forty-nine adolescent (6-week-old) male Wistar rats were included in this study. The rats were divided into seven groups as follows:Group-1, control; Group-2, sham; Group-3, left varicocele-induced; Group-4, varicocele + varicocelectomy + MPFF-treated (for 4 weeks); Group-5, varicocele + MPFF-treated (for 8 weeks); Group-6, varicocele-induced and 4 weeks later, MPFF-treated (for 4 weeks); and Group-7, varicocele + varicocelectomy. MDA was measured in the tissues of both testes using the thiobarbituric acid reactivity method. The ELISA method was used for the quantification of MMP-2, MMP-9 and TIMP-1 in the left testicular tissue. The levels of MDA were significantly higher in the varicocele group than in the other groups. The MDA levels in the left testicular tissues of Group-7 were significantly higher than those of Group 4 (P = 0.03). In the varicocele group, the MMP-2 and MMP-9 levels decreased, whereas the levels of TIMP-1 increased. The tissue levels of MMP-2 in Groups 4, 5 and 7 were significantly higher than those in Group 1 (P < 0.05).

An unbiased approach to identify genes involved in development in a turtle with temperature-dependent sex determination

BACKGROUND

Many reptiles exhibit temperature-dependent sex determination (TSD). The initial cue in TSD is incubation temperature, unlike genotypic sex determination (GSD) where it is determined by the presence of specific alleles (or genetic loci). We used patterns of gene expression to identify candidates for genes with a role in TSD and other developmental processes without making a priori assumptions about the identity of these genes (ortholog-based approach). We identified genes with sexually dimorphic mRNA accumulation during the temperature sensitive period of development in the Red-eared slider turtle (Trachemys scripta), a turtle with TSD. Genes with differential mRNA accumulation in response to estrogen (estradiol-17β; E(2)) exposure and developmental stages were also identified.

RESULTS

Sequencing 767 clones from three suppression-subtractive hybridization libraries yielded a total of 581 unique sequences. Screening a macroarray with a subset of those sequences revealed a total of 26 genes that exhibited differential mRNA accumulation: 16 female biased and 10 male biased. Additional analyses revealed that C16ORF62 (an unknown gene) and MALAT1 (a long noncoding RNA) exhibited increased mRNA accumulation at the male producing temperature relative to the female producing temperature during embryonic sexual development. Finally, we identified four genes (C16ORF62, CCT3, MMP2, and NFIB) that exhibited a stage effect and five genes (C16ORF62, CCT3, MMP2, NFIB and NOTCH2) showed a response to E(2) exposure.

CONCLUSIONS

Here we report a survey of genes identified using patterns of mRNA accumulation during embryonic development in a turtle with TSD. Many previous studies have focused on examining the turtle orthologs of genes involved in mammalian development. Although valuable, the limitations of this approach are exemplified by our identification of two genes (MALAT1 and C16ORF62) that are sexually dimorphic during embryonic development. MALAT1 is a noncoding RNA that has not been implicated in sexual differentiation in other vertebrates and C16ORF62 has an unknown function. Our results revealed genes that are candidates for having roles in turtle embryonic development, including TSD, and highlight the need to expand our search parameters beyond protein-coding genes.

Identification and characterization of an amphioxus matrix metalloproteinase homolog BbMMPL2 responding to bacteria challenge

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases mainly involved in extracellular matrix (ECM) degradation. We have cloned and identified BbMMPL2 as homolog of MMPs from adult amphioxus. Recombinant BbMMPL2 proteins underwent self-processing during refolding in vitro. The final ~23 kDa polypeptide displayed proteolytic activity against ECM components like casein, gelatin, collagen IV and fibrinogen, but not laminin, fibronectin or α1-PI. This activity could be inhibited by GM6001 and TIMP-1/2. In addition, real-time RT-PCR analysis revealed that BbMMPL2 expressed in all issues/organs in adult amphioxus we tested. Its transcription was significantly up-regulated 12 h post immune challenge by Escherichia coli in epidermis and hepatic diverticulum but only slightly increased by Staphyloccocus aureus in epidermis. Furthermore, recombinant BbMMPL2-EGFP expressed in 293T and NIH/3T3 cells showed aggregation in cytoplasm and induced cell death. Our results provided new evidence that MMP was involved in immune response which could be conserved through evolution.

Oocyte specific oolemmal SAS1B involved in sperm binding through intra-acrosomal SLLP1 during fertilization

Molecular mechanisms by which fertilization competent acrosome-reacted sperm bind to the oolemma remain uncharacterized. To identify oolemmal binding partner(s) for sperm acrosomal ligands, affinity panning was performed with mouse oocyte lysates using sperm acrosomal protein, SLLP1 as a target. An oocyte specific membrane metalloproteinase, SAS1B (Sperm Acrosomal SLLP1 Binding), was identified as a SLLP1 binding partner. cDNA cloning revealed six SAS1B splice variants, each containing a zinc binding active site and a putative transmembrane domain, with signal peptides in three variants. SAS1B transcripts were ovary specific. SAS1B protein was first detected in early secondary follicles in day 3 ovaries. Immunofluorescence localized SAS1B to the microvillar oolemma of M2 oocytes. After fertilization, SAS1B decreased on the oolemma and became virtually undetectable in blastocysts. In transfected CHO-K1 cells SAS1B localized to the surface of unpermeabilized cells. Recombinant and native SLLP1 co-localized with SAS1B to the microvillar domain of ovulated M2 oocytes. Molecular interactions between mouse SLLP1 and SAS1B were demonstrated by surface plasmon resonance, far-western, yeast two-hybrid, recombinant- and native-co-IP analyses. SAS1B bound to SLLP1 with high affinity. SAS1B had protease activity, and SAS1B protein or antibody significantly inhibited fertilization. SAS1B knockout female mice showed a 34% reduction in fertility. The study identified SAS1B-SLLP1 as a pair of novel sperm-egg binding partners involving the oolemma and intra-acrosomal compartment during fertilization.

Detection of matrix metalloproteinase (MMP)-2 and MMP-9 in canine seminal plasma

Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that play a central role in degradation of protein components of the extracellular matrix and basement membrane. Previous studies have shown that MMP-2 and MMP-9 are present in human seminal plasma, but there is little information available on the presence of MMPs in canine seminal plasma. This study aims to investigate the presence of MMPs in canine seminal plasma and their clinical manifestation at the level of various semen parameters in canine species. Latent and active forms of MMP-2 and MMP-9 were evaluated using gelatin zymography and their association with semen parameters was examined. Results demonstrate that both latent and active forms of MMP-2 and MMP-9 are present in canine seminal plasma and the latent forms are predominant. The latent and active MMP-9 activities were elevated in the semen with unsatisfactory quality traits and proMMP-2 was inversely correlated with semen quality whereas, MMP-2 was positively correlated with semen quality traits. These findings suggest that proMMP-9 and MMP-9 activation contributes to the variation in semen, while the activation of MMP-2 improves the sperm functionality.

Spermiation: The process of sperm release

Spermiation is the process by which mature spermatids are released from Sertoli cells into the seminiferous tubule lumen prior to their passage to the epididymis. It takes place over several days at the apical edge of the seminiferous epithelium, and involves several discrete steps including remodelling of the spermatid head and cytoplasm, removal of specialized adhesion structures and the final disengagement of the spermatid from the Sertoli cell. Spermiation is accomplished by the co-ordinated interactions of various structures, cellular processes and adhesion complexes which make up the "spermiation machinery". This review addresses the morphological, ultrastructural and functional aspects of mammalian spermiation. The molecular composition of the spermiation machinery, its dynamic changes and regulatory factors are examined. The causes of spermiation failure and their impact on sperm morphology and function are assessed in an effort to understand how this process may contribute to sperm count suppression during contraception and to phenotypes of male infertility.

Gelatinases in Boar Seminal Plasma and Their Relation to Semen Indicators

Matrix metalloproteinases were detected in reproductive tissues and seminal plasma of various animal species. The aim of this study was to determine for the first time the presence of gelatinases and metalloproteases in boar seminal plasma and to correlate the results with semen indicators. Gelatin zymography was used for simultaneous identification and measurement of gelatinase enzyme activity associated with their molecular weights. Several gelatinase forms were identified in seminal plasma of boars. Those that were stimulated by CaCl2 and inhibited by EDTA and phenanthroline were considered as metalloproteases. Negative correlation between semen indicators (sperm index, sperm concentration and concentration of progressive motile sperm) and the concentrations of metalloprotease at 78 kDa and 66 kDa means that higher values of semen indicators correlate with lower concentrations of these metaloproteases in seminal plasma. Gelatinases with molecular weight of 225, 78 and 66 kDa correlated with higher levels of acrosome damage. Samples with sperm index above 110 M/ml contained gelatinases of significantly lower band intensities at 78 and 66 kDa compared to samples with SI less than 110 M/ml. Bands with 225, 78 and 66 kDa are suggested to belong to a dimer of MMP-9, proMMP-2 and mature MMP-2.

Cellular proliferation and vascularization in ovine fetal ovaries: effects of undernutrition and selenium in maternal diet

Sheep were fed a maintenance (M) diet with adequate (A) Se or high (H) Se concentration from 21 days before breeding to day 135 of pregnancy. From day 50 to day 135 of pregnancy (tissue collection day), a portion of the ewes from ASe and HSe groups were fed restricted (R; 60% of M) diet. Fetal ovarian sections were stained for: 1) the presence of proliferating cell nuclear antigen (a marker of proliferating cells) to determine the proportion of proliferating primordial follicles, or the labeling index (LI; percentage of proliferating cells) for primordial, primary, secondary and antral follicles, stromal tissues, and blood vessels; 2) factor VIII (a marker of endothelial cells) or 3) a presence of apoptotic cells/bodies. The number of proliferating primordial follicles and the LI of primordial follicles was decreased by R and/or HSe diets. The LI was similar for theca and granulosa cells, and for secondary or antral follicles, but was greater in secondary and antral than in primordial and primary follicles. R diet and/or Se affected the LI in all follicle types, in stromal tissues and blood vessels. A dense network of blood vessels was detected in the areas containing secondary to antral follicles, medulla, and hilus, but areas containing primordial follicles were poorly vascularized. The number of apoptotic cells was minimal. These results demonstrate that nutrient restriction and/or Se level in the maternal diet affected cellular proliferation in follicles, blood vessels, and stromal tissues in fetal ovaries. Thus, plane of nutrition and Se in the maternal diet may impact fetal ovarian development and function.

TNF alpha-mediated disruption of spermatogenesis in response to Sertoli cell injury in rodents is partially regulated by MMP2

Mono-(2-ethylhexyl) phthalate (MEHP)-induced Sertoli cell injury in peripubertal rodents results in the stimulation of germ cell apoptosis through an interaction of FAS/FASL between these two cell types. During this peripubertal period, an early spike in the incidence of germ cell apoptosis occurs during the first wave of spermatogenesis and is essential for the development of functional spermatogenesis in adults. Our previous observations revealed that soluble tumor necrosis factor alpha (sTNFA) released by germ cells after MEHP exposure consequently resulted in a robust induction of FASL by Sertoli cells. Metalloproteinases (MPs) are essential for processing the TNFA precursor to its soluble form and its ability to bind to TNFRSF1A. The activity of MPs is regulated by the tissue inhibitors of MPs (TIMPs) family. Herein we report that TIMP2 is predominately expressed in Sertoli cells and that protein levels decrease in a time-dependent manner after MEHP exposure. The secretion of matrix MP 2 (MMP2) in primary rat Sertoli cell-germ cell cocultures is induced after MEHP exposure, and its activity increases in a time-dependent manner. The addition of SB-3CT, a specific gelatinase inhibitor, decreases the activity of MMP2 and significantly reduces MEHP-enhanced sTNFA production in primary cocultures. In vivo challenges with SB-3CT decrease sTNFA and reduce MEHP-induced testicular germ cell apoptosis. In primary cocultures, MEHP exposure causes a 9.46-fold increase in sTNFA, while the addition of recombinant MMP2 protein results in a 5.4-fold increase in sTNFA, suggesting that MEHP-induced MMP2 is in part responsible for the activation of TNFA in the testis. Taken together, these observations indicate the distinct role of specific MPs in response to toxicant-induced Sertoli cell injury, providing further insights into the mechanism by which Sertoli cells control the sensitivity of germ cells to undergo apoptosis.

Primordial follicular assembly in humans – revisited

Recent interest in the initial phases of ovarian follicular formation and development has lead to a number of publications in this area, most of which address the autocrine and paracrine factors involved in primordial follicle activation to primary follicle. Primordial follicle assembly (first step in follicle formation) determines the lifetime supply of primordial follicles and remains a poorly understood phenomenon. Despite a number of recent articles that are concentrating on immuno-histochemistry, basic steps in the process are not clear. Hence, we feel it is time to take a step back and see what is available in the literature and identify the gaps in which future research about primordial follicle assembly in humans needs to be directed.

The matricellular protein SPARC is internalized in Sertoli, Leydig, and germ cells during testis differentiation

The gene encoding the matricellular protein secreted protein, acidic and rich in cysteine (SPARC) was identified in a screen for genes expressed sex-specifically during mouse gonad development, as being strongly upregulated in the male gonad from very early in testis development. We present here a detailed analysis of SPARC gene and protein expression during testis development, from 11.5 to 15.5 days post coitum (dpc). Section in situ hybridization analysis revealed that SPARC mRNA is expressed by the Sertoli cells in the testis cords and the fetal Leydig cells, found within the interstitial space between the testis cords. Immunodetection with anti-SPARC antibody showed that the protein was located inside the testis cords, within the cytoplasm of Sertoli and germ cells. In the interstitium, SPARC was present intracellularly within the Leydig cells. The internalization of SPARC in Sertoli, Leydig, and germ cells suggests that it plays an intracellular regulatory role in these cell types during fetal testis development.

Localization and temporal regulation of tissue inhibitor of metalloproteinases-4 in mouse ovary

Tissue inhibitors of metalloproteinases (TIMPs) are potential regulators of tissue remodeling in the ovary. The aim of the present study was to examine the localization and temporal regulation of TIMP-4 protein in the mouse ovary. An induced superovulation model (eCG/hCG) was employed in immature mice to evaluate TIMP-4 protein expression profiles in ovaries collected during the follicular phase, the pre ovulatory period, and the luteal lifespan. Immunofluorescence results indicated that TIMP-4 protein was localized to theca of both antral and preovulatory follicles and adjacent ovarian stroma. After the initiation of luteinization with hCG, TIMP-4 was observed within the luteinizing granulosa cells and persisted throughout the lifespan of the corpus luteum. In the cycling ovary, TIMP-4 signaling localized to corpus luteum from previous estrous cycles, the theca of preovulatory follicles, and appeared to be lower in newly forming corpus luteum. Western analysis further showed that the levels of TIMP-4 increased significantly during the luteinization process of granulosa cells, but no significant change was found among all corpus luteum stages. A putative regulatory mechanism of TIMP-4 expression was identified utilizing an in vitro model. Treatment of cultured granulosa cells with hCG significantly augmented TIMP-4 protein expression levels. Together our data indicate that the luteinization process of granulosa cells is associated with up-regulation of TIMP-4 and that TIMP-4 might play an essential role in maintenance of the luteal function during the whole lifespan of corpus luteum.

Ontogeny and regulation of matrix metalloproteinase activity in the zebrafish embryo by in vitro and in vivo zymography

Remodeling of the extracellular matrix (ECM) during development, angiogenesis, wound healing, tumor metastasis, and other morphogenetic processes depends on the exquisitely regulated activities of matrix metalloproteinases (MMPs). Yet very little is known about the activity patterns of these proteases in vivo. We have employed fluorescent MMP-substrates, both in vitro and in vivo, to characterize patterns of MMP activity in the zebrafish embryo. Qualitatively similar patterns of degradation are detected using native Type I or Type IV collagen substrates, suggesting that multiple MMPs are being regulated concomitantly. MMP activity is observed primarily in ECM-rich structures predicted to be undergoing active remodeling, such as the perichordal sheath and somite boundaries. Patterns of Type I and Type IV collagen hydrolysis are similar, but not identical in embryos of any given stage. Conventional gelatin zymography shows MMPs present in embryos as early as 3-somites (11 h) and our in vivo assays detect Type IV collagen degradation at somite boundaries as early as 4-somites (11.5 h). However, we are unable to detect significant in vitro activity using homogenates made from embryos prior to Prim-16 (31 h). Mixed lysate assays demonstrate that this is the result of endogenous inhibitors present in early embryos, suggesting a model of matrix remodeling regulated by spatially heterogeneous MMP inhibition.

Cloning of the murine ER71 gene (Etsrp71) and initial characterization of its promoter

The ER71 protein belongs to the ETS transcription factor family and is testis-specifically expressed in adult mice. Here we describe the cloning of the respective Etsrp71 gene and promoter. The murine Etsrp71 gene is relatively compact, spanning 3 kb, and is arranged into seven exons and six introns, the majority of which are highly conserved in rat and human. Its promoter is devoid of a TATA box and transcription starts at multiple sites. Furthermore, two ER71 isoforms exist that differ by 22 N-terminal amino acids, but show no difference in DNA binding or transactivation. Close to the transcription initiation sites, we identified a binding site for the transcription factor Sp1. Mutation of this binding site severely diminished the ability of Sp1 to activate the Etsrp71 promoter. The findings reported here may provide avenues for further research elucidating the regulation of Etsrp71 gene activity during embryogenesis and in adult testes.

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.