Expressions of miR-525-3p and its target gene SEMG1 in the spermatozoa of patients with asthenozoospermia.

BACKGROUND: Semenogelin 1 (SEMG1) is an important secretory protein in spermatozoa involved in the formation of a gel matrix encasing ejaculated spermatozoa. Previous studies show that the SEMG1 gene is highly expressed in spermatozoa from patients with asthenozoospermia (AZS); however, the underlying molecular mechanisms are not yet clear. OBJECTIVES: To study the molecular mechanism of high expression of SEMG1 gene and its potential roles in AZS. MATERIALS AND METHODS: Western blot and real-time PCR were used to detect the expression levels of SEMG1 protein and mRNA in the ejaculated spermatozoa from normozoospermic males and AZS patients. Bioinformatics analysis was used to predict miRNAs targeting for SEMG1 3'-untranslated region detection of the expression levels of all the candidate miRNAs in ejaculatory spermatozoa in AZS patients or normozoospermic volunteers. Luciferase reporter assays were performed to confirm it can directly bind to SEMG1. Correlation of miR-525-3p and SEMG1 mRNA expression with clinical sperm parameters were also analyzed. Finally, we conducted a follow-up study of reproductive history about all the subjects. RESULTS: SEMG1 mRNA and protein level were significantly higher in AZS patients compared to that in normozoospermic volunteers (p < 0.001). Subsequently, microRNA-525-3p (miR-525-3p) which was predicted as a candidate regulator of SEMG1 was found lower expressed in ejaculatory spermatozoa in AZS patients (p = 0.0074). Luciferase experiment revealed that microRNA-525-3p could directly target SEMG1 3'-untranslated region and suppress its expression. Importantly, our retrospective follow-up study showed that both low miR-525-3p expression and high SEMG1 expression level was significantly associated with low progressive sperm motility, abnormal sperm morphology, and infertility. DISCUSSION AND CONCLUSION: The elevated expression of SEMG1 and reduced expression of miR-525-3p are associated with AZS and male infertility. Our study provides a potential therapeutic target for the treatment of male infertility or for male contraception.

Abnormal Expression of Sg I is Closely Related to Seminal Vesiculitis.

OBJECTIVE: To investigate firstly the relationship between semenogelin I (Sg I) expression and seminal vesiculitis. Seminal vesiculitis is one of the most common diseases in male urogenital system. However, the cause and the pathogenesis of seminal vesiculitis remain unknown. Sg I, mainly synthesized and secreted by seminal vesicle, is abundant in human seminal plasma and has antibacterial activity. MATERIALS AND METHODS: Tissue samples were collected from 15 normal cases and 28 patients with seminal vesiculitis. Reverse transcription-polymerase chain reaction was performed to detect the expression difference of Sg I messenger ribonucleic acid (RNA) between normal seminal vesicle tissues and seminal vesiculitis tissues. Immunohistochemistry was applied to detect the expression difference of Sg I protein between the 2 groups. RESULTS: Reverse transcription-polymerase chain reaction showed the expression of Sg I messenger RNA in seminal vesiculitis tissues to be significantly lower than in normal seminal vesicle tissues. In most cases with seminal vesiculitis (78.6%), the same result was observed upon immunohistochemical analysis at the protein level. CONCLUSION: Abnormal expression of Sg I is closely related to seminal vesiculitis. Low expression of Sg I may play an important role in the occurrence and the development of seminal vesiculitis through weakening the antibacterial activity of seminal vesicle.

Central T cell tolerance: Identification of tissue-restricted autoantigens in the thymus HLA-DR peptidome.

Promiscuous gene expression (pGE) of tissue-restricted self-antigens (TRA) in medullary thymic epithelial cells (mTECs) is in part driven by the Autoimmune Regulator gene (AIRE) and essential for self-tolerance. The link between AIRE functional mutations and multi-organ autoimmunity in human and mouse supports the role of pGE. Deep sequencing of the transcriptome revealed that mouse mTECs potentially transcribe an unprecedented range of >90% of all genes. Yet, it remains unclear to which extent these low-level transcripts are actually translated into proteins, processed and presented by thymic APCs to induce tolerance. To address this, we analyzed the HLA-DR-associated thymus peptidome. Within a large panel of peptides from abundant proteins, two TRA peptides were identified: prostate-specific semenogelin-1 (an autoantigen in autoimmune chronic prostatitis/chronic pelvic pain syndrome) and central nervous system-specific contactin-2 (an autoantigen in multiple sclerosis). Thymus expression of both genes was restricted to mTECs. SEMG1 expression was confined to mature HLA-DR(hi) mTECs of male and female donors and was AIRE-dependent, whereas CNTN2 was apparently AIRE-independent and was expressed by both populations of mTECs. Our findings establish a link between pGE, MHC-II peptide presentation and autoimmunity for bona fide human TRAs.

Cryopreservation increases coating of bull sperm by seminal plasma binder of sperm proteins BSP1, BSP3, and BSP5.

Artificial insemination with frozen semen allows affordable, worldwide dissemination of gametes with superior genetics. Nevertheless, sperm are damaged by the cryopreservation process. Elucidating the molecular effects of cryopreservation on sperm could suggest methods for improving fertility of frozen/thawed semen. This study was undertaken to examine the effect of cryopreservation on the coating of sperm by binder of sperm (BSP) proteins in seminal plasma. BSP proteins are secreted by the seminal vesicles and coat the surface of sperm by partially intercalating into the outer leaflet of the sperm plasma membrane. The BSP proteins are known to play roles in the formation of the oviductal sperm storage reservoir and in sperm capacitation. We investigated the effects of cryopreservation on the sperm BSP protein coat using Bovipure to separate live sperm from extended semen and then assaying the amounts of BSP proteins on sperm using quantitative western blotting with custom-made antibodies against unique sequences of each BSP protein. Greater amounts of all three BSP proteins (BSP1, BSP3, and BSP5) were detected on frozen/thawed sperm than on fresh sperm. Furthermore, the reduction of BSP3 from 15 to 13 kDa in mass, which occurs during incubation of sperm under mild capacitating conditions, was enhanced by cryopreservation. We concluded that freezing alters the BSP protein coating on sperm, which could account in part for reduced fertility of cryopreserved semen samples.

Expression and localization of acrosin inhibitor in boar reproductive tract.

Proteinases and proteinase inhibitors play key roles in almost all physiological processes. Proteinase inhibitors are present in all tissues and body fluids. They interfere with the activity of proteinases and thus maintain homeostasis. The main role of proteinase inhibitors in the reproductive tract is the inactivation of prematurely released hydrolytic enzymes from damaged spermatozoa and the protection of reproductive tracts and spermatozoa against proteolytic degradation. In the boar reproductive system, acrosin inhibitors are found in seminal plasma and on spermatozoa. The amino acid sequence of seminal plasma and sperm-associated acrosin inhibitors is 90% identical, and their biochemical properties have been completely resolved. However, their origin and localization have not been fully elucidated. Using rabbit polyclonal antibody, we have studied the expression and localization of the seminal plasma acrosin inhibitor in the boar reproductive tract. The antibody recognizes a 12-kDa band in extracts from the cauda epididymidis, seminal vesicles, prostate, and Cowper's glands, and immunofluorescence has revealed the acrosin inhibitor in the epithelium and lumen of these organs. Gene expression of the acrosin inhibitor has been studied by reverse transcription together with the polymerase chain reaction. Acrosin inhibitor mRNA transcript is detectable in the epididymis, seminal vesicles, prostate, and Cowper's glands. The antibody has localized the acrosin inhibitor on the surface of epididymal and ejaculated spermatozoa in the acrosomal region. In extracts from epididymal and ejaculated spermatozoa, the specific antibody recognizes acrosin inhibitor at 8 kDa and 12 kDa. The presence of acrosin inhibitor on the sperm surface as a protective molecule for receptors mediating the sperm-zona pellucida binding suggests that it is crucial for the reproductive process.

Ganglioside GM1 mediates decapacitation effects of SVS2 on murine spermatozoa.

Prior to fertilization, mammalian spermatozoa need to acquire fertilizing ability (capacitation) in the female reproductive tract. On the other hand, capacitated spermatozoa reversibly lose their capacitated state when treated with seminal plasma (decapacitation). Previously, we demonstrated that a mouse seminal plasma protein, SVS2, is a decapacitation factor and regulates sperm fertilizing ability in vivo. Here, we examined the mechanisms of regulation of fertilizing ability by SVS2. Capacitation appears to be mediated by dynamic changes in lipid rafts since release of the cholesterol components of lipid rafts in the sperm plasma membrane is indispensable for capacitation. When the ejaculated spermatozoa were stained with a cholera toxin subunit B (CTB) that preferably interacts with ganglioside GM1, another member of the lipid rafts, the staining pattern of the sperm was the same as the binding pattern of SVS2. Interestingly, SVS2 and CTB competitively bound to the sperm surface with each other, suggesting that the binding targets of both molecules are the same, that is, GM1. Molecular interaction studies by the overlay assay and the quartz crystal microbalance analysis revealed that SVS2 selectively interacts with GM1 rather than with other gangliosides. Furthermore, external addition of GM1 nullified SVS2-induced sperm decapacitation. Thus, ganglioside GM1 is a receptor of SVS2 and plays a crucial role in capacitation in vivo.

[Inhibition activity of semenogelin and its peptides to human spermatozoa].

OBJECTIVE: To study the inhibition activity of Semenogelin (Sg) and its different peptides to human spermatozoa. METHODS: Human Sg DNA and its N-terminal Sg and C-terminal Sg DNA were cloned into PET-100 vector. Positive colonies were screened and transformed into E. Coli BL21 (DE3). Recombinant Sg and its peptides were induced and expressed in high competent E. coli BL21 (DE3) , and purified by 50% Ni-NTA column. Inhibition activity assay was done by adding 4 different concentrations of semenogelin and its two peptides, 0, 1, 5 and 10 ng/microl, to human spermatozoa. RESULTS: The peptide of Semenogelin that inhibits the activity of human spermatozoa was located in its N-terminal fragment. C-terminal Sg did not inhibit the activity of spermatozoa. CONCLUSION: N-terminal Sg is the inhibition peptide of the whole molecular Sg. During semen liquefaction, this peptide should be cut off from the surface of human spermatozoa before they move forward.

Mutations in two short noncoding mononucleotide repeats in most microsatellite-unstable colorectal cancers.

DNA mismatch repair (MMR)-deficient cells typically accumulate mutations in short repetitive DNA tracts. This microsatellite instability (MSI) facilitates malignant transformation when affecting genes with growth-related and caretaker functions. To date, several putative MSI target genes have been proposed mainly based on high mutation frequency within their coding regions. However, some intronic repeat mutations have also been suggested to associate with MSI tumorigenesis, indicating the need for additional analyses on noncoding repeats. Here we have analyzed an intronic T9 repeat of semenogelin I (SEMG1) and report mutation frequencies of 51% (75 of 146) and 62% (8 of 13) in MMR-deficient primary colorectal cancers and cell lines, respectively. The putative effect of the SEMG1 mutations was assessed by RNA and protein level analyses, but no differences were detected between colorectal cancer cell lines with different SEMG1 status. Subsequently, the general background mutation frequency of MSI colorectal cancers was assessed by screening for intergenic T9 repeat alterations. One of 10 examined repeats was mutated in 70% (102 of 145) of the colorectal cancers evaluated. The frequencies observed here are notably higher than previously published in noncoding repeats shorter than 10 bp in MMR-deficient primary tumors. Our results indicate that high mutation frequencies, similar or higher than those observed in proposed and approved target genes, can be detected in repeat tracts of MSI tumors without any apparent selection pressure. These data call for urgent and thorough large-scale evaluation of mutation frequencies in neutral short repetitive sequences in MMR-deficient tumors.

Pattern of gene expression and immune responses to Semenogelin 1 in chronic hematologic malignancies.

Normal testicular-specific proteins are frequently aberrantly expressed by tumor cells. Based on this, we have investigated Semenogelin 1, a major protein of human semen coagulum thought to be highly specific to seminal vesicles, in leukemic cells. Using reverse transcription-polymerase chain reaction, Semenogelin 1 gene was frequently expressed in chronic myeloid leukemia (5 of 8, 62.5%) and chronic lymphocytic leukemia (5 of 12, 41.7%) but rarely in multiple myeloma (2 of 30, 6.7%). The gene was not expressed in bone marrow or peripheral blood from healthy donors. Semenogelin 1 expression is normally confined to the testis, suggesting that it is a novel Cancer-Testis (CT) antigen. Translation of the mRNA to Semenogelin 1 protein was confirmed by Western blot analysis of tumor cell lysates and by immunocytochemistry. The recombinant Semenogelin 1 protein was used with a control Escherichia coli-derived recombinant protein in ELISA and Western blot analysis to show that high titer IgG antibodies against Semenogelin 1 were detected in some patients, suggesting the in vivo immunogenicity of the protein. Immune responses predicted gene expression by the leukemia cells. Semenogelin 1 was also frequently coexpressed with other CT antigens, Sperm protein 17 and SPAN-Xb. These results therefore indicate that Semenogelin 1 is a novel CT antigen capable of inducing B-cell responses in vivo in chronic leukemias.

Expression of caltrin in the baculovirus system and its purification in high yield and purity by cobalt (II) affinity chromatography.

Direct protein extraction from animals is the only approach available to obtain caltrin, calcium transport inhibitor. Here we report the expression and purification of caltrin, previously shown to hinder the influx of calcium into epididymal spermatozoa. Cloning of the caltrin gene into the pCDNA3.1 V5/His-TOPO vector and the subsequent ligation of the caltrin-His sequence into the transfer vector pBacPAK9 allowed the expression of recombinant caltrin using the baculovirus expression vector system (BEVS). Recombinant His-tagged caltrin was purified utilising both nickel (II)-nitrilotriacetic acid (Ni(2+)-NTA) and cobalt (II)-carboxymethylaspartate (Co(2+)-CmAsp) immobilised metal affinity chromatography (IMAC). Using the BEVS, caltrin-His was identified in the supernatant and in the cell lysate, suggesting that caltrin is a secreted protein. Based on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot results, purified recombinant caltrin-His was ascertained to be approximately 14.5kDa. Purification under the Co(2+) system yielded significantly purer protein samples when compared to the Ni(2+) system. Furthermore, Co(2+) was observed to bind the recombinant caltrin-His protein with higher efficiency and specificity and to yield a higher total protein concentration. Collectively, our results indicate that the Co(2+) system would be a better approach for purifying caltrin-His proteins than the Ni(2+).