Sperm functional aspects and enriched proteomic pathways of seminal plasma of adult men with obesity.

BACKGROUND: Previous studies have demonstrated an association between obesity and the decreased male fertility. OBJECTIVE: to observe the mechanisms by which obesity affects semen quality. MATERIALS AND METHODS: A prospective study was performed including 47 male volunteers, of which 27 were obese group (body mass index >30 kg/m2 ) and 20 were eutrophic (body mass index between 18.5 and 25 kg/m2 ) controls. Sperm functional analysis was performed. The remaining seminal plasma was pooled-four pools per group- and submitted to proteomic analysis by liquid chromatography coupled to tandem mass spectrometry. Groups were compared by an unpaired Student's t-test. Differentially expressed proteins were submitted to functional enrichment analysis using the online platform PantherDB. RESULTS: Obese men presented decreased non-progressive motility, morphology, acrosome integrity, mitochondrial activity, and increased sperm DNA fragmentation. In proteomics analysis, 69 proteins were differentially expressed between the two groups. Among them, one protein was absent, 19 were down-regulated, 49 were up-regulated, and one was exclusive in the study group. The main functions enriched were as follows: negative regulation of the intrinsic pathway of apoptosis, activation of immune and inflammatory, antioxidant activity, among others. CONCLUSION: molecular pathways suggest there is a causative link, and that the effector mechanisms alter sperm metabolic status and defective testicular selection 5 mechanisms.

Molecular pathways of varicocele and its repair - A paired labelled shotgun proteomics approach.

Varicocelectomy is associated to improved semen quality and sperm functional quality, but individual response is highly variable. Thus, a prospective study was performed including 25 men who collected a semen sample before and 12 months after subinguinal microsurgical varicocelectomy. Semen analysis, sperm functional analysis, and seminal plasma proteomic analysis was performed before and 12 months after varicocelectomy, and according to improvement or not of semen quality (positive and negative outcome). Varicocelectomy led to an increase in semen volume and sperm count, morphology, and mitochondrial activity. In the pre- vs. post-samples, 698 proteins were quantified - 91 differentially expressed after varicocelectomy. In the positive vs. negative outcome analysis, 647 proteins were identified - 151 differentially expressed in the negative outcome group and 30 differentially expressed in the positive outcome group. Tripeptidyl peptidase-1 offered a predictive value for outcome, with an area under a ROC curve of 84.5%. It seems TPP1 is an outcome predictor for varicocelectomy in adults. More importantly, this study demonstrates that the seminal plasma proteome is different in men with varicocele when compared to post-treatment samples from the same individuals. Understanding and monitoring the molecular mechanisms of semen may further establish therapeutic options for these men. SIGNIFICANCE: Although several large-scale studies have demonstrated varicocele is unequivocally associated to male infertility, these same studies have also demonstrated that varicocele is not a determinant of male infertility. We have yet to answer the question of why don't all men with varicocele present with infertility. Varicocele treatment improves semen quality, but its results are variable, and one cannot know who will and who will not benefit from surgical treatment. Results from this study strongly advance a concept that our previous studies have shown: that men with varicocele present an inflammatory semen profile. We have further demonstrated that men operated for varicocele present a decrease in this inflammatory profile, and that when they do not, semen quality remains unaltered. Trypeptidil peptidase-1, a seminal protein, was 3-fold higher in men with a positive outcome after the procedure, when compared to men with a negative outcome. Therefore, inflammation seems to be a central point to varicocele-derived male infertility.

Determination of testicular function in adolescents with varicocoele - a proteomics approach.

The goal of this study was to determine seminal plasma biomarkers of testicular function in adolescents with varicocoele and to verify enriched gene ontology terms associated to these differential proteomes. An observational study was carried out in an academic research environment. A total of 77 adolescent patients were recruited from a local public school, of which 23 were without varicocoele and with normal semen analysis (control group), 37 were with varicocoele and normal semen (VNS) parameters, and 17 were with varicocoele and altered semen (VAS) parameters. Two semen collections were provided with a 1-week interval, after 2-5 days of ejaculatory abstinence. Seminal plasma proteins were identified and quantified utilizing a label-free shotgun proteomics approach, generating (i) proteins differentially expressed in each group (control, VNS, and VAS) and putative biomarkers using multivariate statistics followed by discriminant analysis. Confirmatory analysis was performed for two proteins by western blotting. Enriched biological processes and molecular functions were determined using gene ontology analysis. In total, 541 proteins were identified and quantified: 108 exclusive or overexpressed in controls, 26 in the VNS group, and 13 in the VAS group. The suggested biomarkers are Cab45/SDF4 (Q9BRK5), protein lefty-1 (O75610), DNase I (P24855), PAP2-alpha (O14494), IBP-7 (Q16270), HDC (P01860), and CRISP-3 (P54108). Western blotting results showed that Cab45 was significantly underexpressed in both varicocoele groups, and CRISP-3 was significantly overexpressed in seminal plasma of adolescents with VAS. In conclusion, specific biomarkers of spermatogenesis and homeostasis are observed in adolescents without varicocoele, and the presence of a palpable varicocoele progressively shifts these adolescents toward initially an immune response, and finally toward a chronic inflammatory profile. This shift is accompanied by decreased semen quality.

Unbiased label-free quantitative proteomic profiling and enriched proteomic pathways in seminal plasma of adult men before and after varicocelectomy.

STUDY QUESTION: Does the seminal plasma proteomic profile and functional enrichment of gene ontology terms change after microsurgical varicocelectomy? Are there any potential targets for diagnosis or therapeutic intervention in varicocele? SUMMARY ANSWER: A shift in state from a responsive-to-stress condition before varicocele correction to a responsive-to-environment condition after varicocelectomy was observed in enriched proteomic pathways. WHAT IS KNOWN ALREADY: Varicocele may lead to many adverse effects, including failure of testicular growth and development, and is associated with decreased semen quality and increased semen oxidative stress. Varicocelectomy is the treatment of choice, and is associated with improved semen quality, but little is known regarding the underlying molecular mechanisms and post-genomic pathways following intervention. STUDY DESIGN, SIZE, DURATION: A prospective study was carried out including 18 adult men with varicocele. These patients provided one semen sample before they were submitted for bilateral varicocele repair through microsurgical varicocelectomy, and one other semen sample 90 days after the surgery. PARTICIPANTS/MATERIALS, SETTING, METHODS: An aliquot of each semen sample was used for unbiased proteomics analysis by a label-free quantitative approach (2D nanoUPLC-ESI-MS(E)). Samples were pooled according to group (normalized to protein content) and run in quadruplicate. These quadruplicate runs provided degrees of freedom in order to compare groups using a non-parametric Mann-Whitney test for quantified proteins. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 316 proteins were quantified or identified, of which 91 were exclusively identified or quantified in one of the groups (53 in the pre- and 38 in the post-varicocelectomy group), and 68 were quantified in both groups and submitted to statistical analysis, of which 5 were overrepresented in the pre-varicocelectomy group (P < 0.05). In enriched functional analysis, binding and response to stimulus functions were enriched in a common cluster (present in both groups), nitric oxide metabolism and tetratricopeptide repeat domain-binding functions were enriched in the pre-varicocelectomy group, and response to reactive oxygen species, gluconeogenesis, nicotinamide adenine dinucleotide-binding and protein stabilization were enriched in the post-varicocelectomy. LIMITATIONS, REASONS FOR CAUTION: Because a shotgun proteomics analysis was chosen in order to generate a list of putative biomarkers, a targeted follow-up study should be performed to confirm these biomarkers. WIDER IMPLICATIONS OF THE FINDINGS: The proteins found in both groups possess functions usually found in human semen. The enriched function analysis demonstrated a shift back to homeostasis after varicocelectomy, suggesting that varicocele correction promotes return of semen to a physiological state. STUDY FUNDING/COMPETING INTEREST(S): The funding for this project was received from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) as a scholarship for Ms Camargo. There was no conflict of interest.

PCB-induced oxidative stress in the unicellular marine dinoflagellate Lingulodinium polyedrum.

The susceptibility of the dinoflagellate Lingulodinium polyedrum to Arochlor 1254, a commercial mixture of polychlorinated biphenyl (PCB) congeners was examined through toxicity bioassays based on cell survival and measures of oxidative balance and adaptive response to PCB stress. The highest Arochlor 1254 concentration that did not cause observed effects (NOEC) on cell growth was 100 (48 h) and 25 ppb (96 h). The concentration that caused maximum effect (MEC) was 300 ppb (48 h) and 250 ppb (microl L(-1)) (96 h). The concentrations that promoted 50% cell death (LC50) were 146 and 122 ppb after 48 and 96 h, respectively. The cell numbers were lower after 96 h of exposure than after 48 h, suggesting that neither recovery nor growth occurred. Under exposure to 120 ppb Arochlor 1254 for 48 h the oxidative damage in proteins was 121% higher than the control, as measured by reactive carbonyl levels, but no oxidative damage was found in lipids measured as malondialdehyde contents. Total superoxide dismutase (SOD) activity increased to plateau levels 146% greater than control values. The cells also exhibited increased ascorbate peroxidase (APx) activity (50%) and peridinin content (27%). No changes were observed in beta-carotene under these experimental conditions. Therefore, SOD and APx induction and increased peridinin content may be principal primary adaptive responses to an increase of reactive oxygen species in Arochlor 1254 stress as indicated by protein oxidative damage and are an early marker of Arochlor 1254 contamination.