Molecular cloning of complementary DNA encoding mouse seminal vesicle-secreted protein SVS I and demonstration of homology with copper amine oxidases

Glucagon-Like Peptide 1 Receptor Agonist Improves Renal Tubular Damage in Mice with Diabetic Kidney Disease

PURPOSE

This study aims to investigate the renal protective effect of glucagon-like peptide 1 receptor agonist (GLP-1RA) on improving renal tubular damage in diabetic kidney disease (DKD) and to explore the potential mechanism of GLP-1RA on renal tubular protection.

METHODS

Long-acting GLP-1RA was used to treat DKD mice for 12 weeks. The label-free quantitative proteomic analysis of renal proteins was conducted to explore the differentially expressed proteins (DEPs) in the renal tissues of the control, DKD and GLP-1RA groups. The DEPs and markers of renal tubular injury were verified by qPCR in vivo and in vitro. The expression of glucagon-likepeptide-1 receptor (GLP-1R) in renal tubules was determined by immunofluorescence staining.

RESULTS

GLP-1RA treatment significantly improved the tubular damages in kidney tissues of DKD mice and mTEC cells stimulated by high glucose (HG). Proteomics analysis revealed that 30 proteins in kidney tissue were differentially expressed among three groups. Seminal vesicle secretory protein 6 (SVS6) was the most differentially expressed protein in kidney tissues among three groups of mice. The expression changes of Svs6 mRNA in vitro and in vivo detected by qPCR were consistent with the results of proteomic analysis. Furthermore, reduction of Svs6 expression by SVS6 siRNA could attenuate HG-stimulated tubular injury in mTEC cells. Immunofluorescence staining also found that GLP-1R was widely expressed in renal tubules in vitro and in vivo.

CONCLUSION

GLP-1RA significantly improved renal tubular damage in DKD mice. SVS6 may be a potential therapeutic target for GLP-1RA in the treatment of DKD.

Identification of the major rabbit and guinea pig semen coagulum proteins and description of the diversity of the REST gene locus in the mammalian clade Glires

The seminal vesicle secretions of guinea pig and rabbit were analyzed for semen coagulum proteins. Using SDS-PAGE we discovered a previously not fully recognized semen coagulum protein, Svp5, in the guinea pig and a single predominant component, SVP200, in the rabbit. Potential genes of these proteins were identified in genome databases by their homology with human and murine genes. The structure of their fullength transcripts was determined using seminal vesicle cDNA and sequencing primers based on genomic sequences. Homology searching indicated that both Svp5 and SVP200 were synthesized from composite genes that were the result of merger between two genes showing homology with human SEMG2 and PI3. For a deeper understanding of the evolution of the genes, we retrieved and analyzed genome sequences from the REST gene loci, encompassing genes of semen coagulum proteins and related rapidly evolving seminal vesicle-transcribed genes, of 14 rodents and 2 lagomorphs. The analysis showed that rodents of the suborders myomorpha, hystricomorpha, and castorimorpha had unique sets of REST genes, whereas sciuromorpha seemed to be lacking such genes. It also indicated a closer relationship between myomorpha and castorimorpha than to rodents of the two other analyzed suborders. In the lagomorph species, the pika appeared to be devoid of REST genes, whereas the rabbit had a single expressed REST gene, SVP200, and two pseudogenes. The structural similarity of semen coagulum proteins in rabbit and hystricomph species suggests that they are closely related. This was also supported by other similarities at their REST gene loci, e.g. the finding of a PI3-like gene in the rabbit that also had features in common with caltrin2 of hystricomorph rodents. The homologies indicate that hystricomorpha may have separated from myomorpha and castorimorpha before the separation of hystricomorpha from lagomorpha.

Seminal vesicle proteins SVS3 and SVS4 facilitate SVS2 effect on sperm capacitation

Mammalian spermatozoa acquire their fertilizing ability in the female reproductive tract (sperm capacitation). On the other hand, seminal vesicle secretion, which is a major component of seminal plasma, inhibits the initiation of sperm capacitation (capacitation inhibition) and reduces the fertility of the capacitated spermatozoa (decapacitation). There are seven major proteins involved in murine seminal vesicle secretion (SVS1-7), and we have previously shown that SVS2 acts as both a capacitation inhibitor and a decapacitation factor, and is indispensable for in vivo fertilization. However, the effects of SVSs other than SVS2 on the sperm have not been elucidated. Since mouse Svs2-Svs6 genes evolved by gene duplication belong to the same gene family, it is possible that SVSs other than SVS2 also have some effects on sperm capacitation. In this study, we examined the effects of SVS3 and SVS4 on sperm capacitation. Our results showed that both SVS3 and SVS4 are able to bind to spermatozoa, but SVS3 alone showed no effects on sperm capacitation. On the other hand, SVS4 acted as a capacitation inhibitor, although it did not show decapacitation abilities. Interestingly, SVS3 showed an affinity for SVS2 and it facilitated the effects of SVS2. Interaction of SVS2 and spermatozoa is mediated by the ganglioside GM1 in the sperm membrane; however, both SVS3 and SVS4 had weaker affinities for GM1 than SVS2. Therefore, we suggest that separate processes may cause capacitation inhibition and decapacitation, and SVS3 and SVS4 act on sperm capacitation cooperatively with SVS2.

Genes encoding WFDC- and Kunitz-type protease inhibitor domains: are they related?

We have previously demonstrated that the genes of SCPs (semen coagulum proteins) and the WFDC (whey acidic protein four-disulfide core)-type protease inhibitor elafin are homologous in spite of lacking similarity between their protein products. This led to the discovery of a locus on human chromosome 20, encompassing genes of the SCPs, SEMG1 (semenogelin I) and SEMG2, and 14 genes containing the sequence motif that is characteristic of WFDC-type protease inhibitors. We have now identified additional genes at the locus that are similarly organized, but which give rise to proteins containing the motif of Kunitz-type protease inhibitors. Here, we discuss the evolution of genes encoding SCPs and describe mechanisms by which they and genes with Kunitz motifs might have evolved from genes with WFDC motifs. We can also demonstrate an expansion of the WFDC locus with 0.6 Mb in the cow. The region, which seems to be specific to ruminants, contains several genes and pseudogenes with Kunitz motifs, one of which is the much-studied BPTI (bovine pancreatic trypsin inhibitor).

Deletion of androgen receptor in the smooth muscle of the seminal vesicles impairs secretory function and alters its responsiveness to exogenous testosterone and estradiol

The seminal vesicles (SVs), like much of the male reproductive tract, depend on androgen-driven stromal-epithelial interactions for normal development, structure, and function. The primary function of the SVs is to synthesize proteins that contribute to the seminal plasma and this is androgen dependent. However, the cell-specific role for androgen action in adult SVs remains unclear. This study analyzed the SV in mice with targeted ablation of androgen receptors specifically in smooth muscle cells (PTM-ARKO) to determine in vivo whether it is androgen action in a subset of the SV stroma, the smooth muscle cells, that drives epithelial function and identity. These mice have significantly smaller SVs in adulthood with less smooth muscle and reduced epithelial cell height. Less epithelial cell proliferation was observed in adult PTM-ARKO SVs, compared with controls, and production of seminal proteins was reduced, indicating global impairment of epithelial cell function in PTM-ARKO SVs. None of these changes could be explained by altered serum testosterone or estradiol concentrations. We also demonstrate altered SV responsiveness to exogenous testosterone and estradiol in PTM-ARKO mice, indicating that smooth muscle androgen receptors may limit the SV epithelial proliferative response to exogenous estrogens. These results therefore demonstrate that the smooth muscle cells play a vital role in androgen-driven stromal-epithelial interactions in the SV, determining epithelial cell structure and function as well as limiting the SV epithelial proliferative response to exogenous estrogens.

Comparative proteomic analysis of proteins involved in the tumorigenic process of seminal vesicle carcinoma in transgenic mice

We studied the seminal vesicle secretion (SVS) of transgenic mice by using one-dimensional gel electrophoresis combined with LTQ-FT ICR MS analysis to explore protein expression profiles. Using unique peptide numbers as a cut-off criterion, 79 proteins were identified with high confidence in the SVS proteome. Label-free quantitative analysis was performed by using the IDEAL_Q software program. Furthermore, western blot assays were performed to validate the expression of seminal vesicle proteins. Sulfhydryl oxidase 1, glia-derived nexin, SVS1, SVS3, and SVS6 showed overexpression in SVS during cancer development. With high sequence similarity to human semenogelin, SVS2 is the most abundance protein in SVS and is dramatically decreased during the tumorigenic process. Our results indicate that these protein candidates could serve as potential targets for monitoring seminal vesicle carcinoma. Moreover, this information can provide clues for investigating seminal vesicle secretion-containing seminal plasma for related human diseases.

Phylogenetic and chromosomal analyses of multiple gene families syntenic with vertebrate Hox clusters

Background

Ever since the theory about two rounds of genome duplication (2R) in the vertebrate lineage was proposed, the Hox gene clusters have served as the prime example of quadruplicate paralogy in mammalian genomes. In teleost fishes, the observation of additional Hox clusters absent in other vertebrate lineages suggested a third tetraploidization (3R). Because the Hox clusters occupy a quite limited part of each chromosome, and are special in having position-dependent regulation within the multi-gene cluster, studies of syntenic gene families are needed to determine the extent of the duplicated chromosome segments. We have analyzed in detail 14 gene families that are syntenic with the Hox clusters to see if their phylogenies are compatible with the Hox duplications and the 2R/3R scenario. Our starting point was the gene family for the NPY family of peptides located near the Hox clusters in the pufferfish Takifugu rubripes, the zebrafish Danio rerio, and human.

Results

Seven of the gene families have members on at least three of the human Hox chromosomes and two families are present on all four. Using both neighbor-joining and quartet-puzzling maximum likelihood methods we found that 13 families have a phylogeny that supports duplications coinciding with the Hox cluster duplications. One additional family also has a topology consistent with 2R but due to lack of urochordate or cephalocordate sequences the time window when these duplications could have occurred is wider. All but two gene families also show teleost-specific duplicates.

Conclusion

Based on this analysis we conclude that the Hox cluster duplications involved a large number of adjacent gene families, supporting expansion of these families in the 2R, as well as in the teleost 3R tetraploidization. The gene duplicates presumably provided raw material in early vertebrate evolution for neofunctionalization and subfunctionalization.

Adaptive evolution in rodent seminal vesicle secretion proteins

Proteins involved in reproductive fitness have evolved unusually rapidly across diverse groups of organisms. These reproductive proteins show unusually high rates of amino acid substitutions, suggesting that the proteins have been subject to positive selection. We sought to identify seminal fluid proteins experiencing adaptive evolution because such proteins are often involved in sperm competition, host immunity to pathogens, and manipulation of female reproductive physiology and behavior. We performed an evolutionary screen of the mouse prostate transcriptome for genes with elevated evolutionary rates between mouse and rat. We observed that secreted rodent prostate proteins evolve approximately twice as fast as nonsecreted proteins, remarkably similar to findings in the primate prostate and in the Drosophila male accessory gland. Our screen led us to identify and characterize a group of seminal vesicle secretion (Svs) proteins and to show that the gene Svs7 is evolving very rapidly, with many amino acid sites under positive selection. Another gene in this group, Svs5, showed evidence of branch-specific selection in the rat. We also found that Svs7 is under selection in primates and, by using three-dimensional models, demonstrated that the same regions have been under selection in both groups. Svs7 has been identified as mouse caltrin, a protein involved in sperm capacitation, the process responsible for the timing of changes in sperm activity and behavior, following ejaculation. We propose that the most likely explanation of the adaptive evolution of Svs7 that we have observed in rodents and primates stems from an important function in sperm competition.

A locus on chromosome 20 encompassing genes that are highly expressed in the epididymis

During liquefaction of the ejaculate, the semen coagulum proteins semenogelin I (SEMG1) and semenogelin II (SEMG2) are degraded to low molecular mass fragments by kallikrein-related peptidase 3 (KLK3), also known as prostate-specific antigen. Semenogelin molecules initiate their own destruction by chelating Zn(2+) that normally would completely inhibit the proteolytic activity of KLK3. In a similar way, semenogelins might regulate the activity of kallikrein-related peptidases in the epididymis, something that might be of importance for the maturation of spermatozoa or generation of anti-bacterial peptides. Studies on the evolution of semen coagulum proteins have revealed that most of them carry an exon that displays a rapid and unusual evolution. As a consequence, homologous proteins in rodents and primates show almost no conservation in primary structure. Further studies on their evolution suggest that the progenitor of the semen coagulum proteins probably was a protease inhibitor that might have displayed antimicrobial activity. The semenogelin locus on chromosome 20 contains at least 17 homologous genes encoding probable protease inhibitors with homology to semen coagulum proteins. All of these are highly expressed in the epididymis where they, similar to the semenogelins, could affect the maturation of spermatozoa or display antibacterial properties.