EVIDENCE FAVORING SPERM SELECTION OVER SPERM COMPETITION IN THE INTERACTION BETWEEN HUMAN SEMINAL PLASMA AND SPERM MOTILITY IN VITRO

Standardized swim-up trials are used in in vitro fertilization clinics to select particularly motile spermatozoa in order to increase the probability of a successful fertilization. Such trials demonstrate that sperm with longer telomeres have higher motility and lower levels of DNA damage. Regardless of whether sperm motility, and successful swim-up to fertilization sites, is a direct or correlational effect of telomere length or DNA damage, covariation between telomere length and sperm performance predicts a relationship between telomere length and probability of paternity in sperm competition, a prediction that for ethical reasons cannot be tested on humans. Here, we test this prediction in sand lizards ( Lacerta agilis ) using experimental data from twice-mated females in a laboratory population, and telomere length in blood from the participating lizards. Female identity influenced paternity (while the mechanism was not identified), while relatively longer male telomeres predicted higher probability of paternity. We discuss potential mechanisms underpinning this result.

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Abnormal arachidonic acid metabolic network may reduce sperm motility via P38 MAPK

Open Biology ◽

10.1098/rsob.180091 ◽

2019 ◽

Vol 9 (4) ◽

pp. 180091 ◽

Cited By ~ 2

Author(s):

Lisha Yu ◽

Xiaojing Yang ◽

Bo Ma ◽

Hanjie Ying ◽

Xuejun Shang ◽

...

Keyword(s):

Arachidonic Acid ◽

Cytochrome P450 ◽

Metabolic Network ◽

P38 Mapk ◽

Sperm Motility ◽

Seminal Plasma ◽

Metabolic Pathways ◽

Mitogen Activated Protein Kinase ◽

Mapk Activation

Asthenozoospermia is a common cause of male infertility, the aetiology of which remains unclear in 50–60% of cases. The current study aimed to characterize metabolic alterations in asthenozoospermic seminal plasma and to explore the signalling pathways involved in sperm motility regulation. At first, high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry was used to detect the targeted metabolic network of arachidonic acid (AA). Metabolomic multivariate data analysis showed significant distinction of AA metabolites between asthenozoospermic and healthy seminal plasma. AA as well as its lipoxygenase (LOX) and cytochrome P450 metabolites were found to be abnormally increased, while cyclooxygenase (COX) metabolites were complicatedly disturbed in asthenozoospermic volunteers compared with those in healthy ones. In vitro experiments and western blot analysis of sperm cells revealed a decrease in sperm motility and upregulation of sperm phosphor-P38 induced by AA. P38 inhibitor could increase AA-reduced sperm motility. Also, all the inhibitors of the three metabolic pathways of AA could block AA-induced P38 mitogen-activated protein kinase (MAPK) activation and further improve sperm motility. We report here for the first time that an abnormal AA metabolic network could reduce sperm motility via P38 MAPK activation through the LOX, cytochrome P450 and COX metabolic pathways, which might be an underlying pathomechanism of asthenozoospermia.

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Decreased piRNAs in Infertile Semen Are Related to Downregulation of Sperm MitoPLD Expression

Frontiers in Endocrinology ◽

10.3389/fendo.2021.696121 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yeting Hong ◽

Yanqian Wu ◽

Jianbin Zhang ◽

Chong Yu ◽

Lu Shen ◽

...

Keyword(s):

Male Infertility ◽

Sperm Motility ◽

Seminal Plasma ◽

Molecular Mechanisms ◽

Molecular Biomarkers ◽

Loss Of Function ◽

Human Seminal Plasma ◽

High Concentrations ◽

Tight Correlation ◽

Infertile Patients

Currently, the molecular mechanisms underlining male infertility are still poorly understood. Our previous study has demonstrated that PIWI-interacting RNAs (piRNAs) are downregulated in seminal plasma of infertile patients and can serve as molecular biomarkers for male infertility. However, the source and mechanism for the dysregulation of piRNAs remain obscure. In this study, we found that exosomes are present in high concentrations in human seminal plasma and confirmed that piRNAs are predominantly present in the exosomal fraction of seminal plasma. Moreover, we showed that piRNAs were significantly decreased in exosomes of asthenozoospermia patients compared with normozoospermic men. By systematically screening piRNA profiles in sperms of normozoospermic men and asthenozoospermia patients, we found that piRNAs were parallelly reduced during infertility. At last, we investigated the expression of some proteins that are essential for piRNAs biogenesis in sperms and therefore identified a tight correlation between the levels of spermatozoa piRNA and MitoPLD protein, suggesting that the loss-of-function of MitoPLD could cause a severe defect of piRNA accumulation in sperms. In summary, this study identified a parallel reduction of piRNAs and MitoPLD protein in sperms of asthenozoospermia patients, which may provide pathophysiological clues about sperm motility.

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229.Seminal plasma TGFβ activates pro-inflammatory cytokine synthesis in human cervical epithelial cells

Reproduction Fertility and Development ◽

10.1071/srb04abs229 ◽

2004 ◽

Vol 16 (9) ◽

pp. 229 ◽

Cited By ~ 1

Author(s):

D. J. Sharkey ◽

S. A. Robertson

Keyword(s):

Epithelial Cells ◽

Seminal Plasma ◽

Model Systems ◽

Human Seminal Plasma ◽

Neutralising Antibodies ◽

Active Constituents ◽

Gm Csf ◽

Cytokine Synthesis ◽

Cervical Epithelial Cells

Exposure to semen at intercourse in women elicits an inflammation-like response characterised by recruitment of inflammatory cells and expression of pro-inflammatory cytokines including GM-CSF, interleukin-6 (IL-6) and IL-8 (1). Studies in animal models have implicated TGFβ as the major active moiety in seminal plasma, and we have shown previously that TGFβ1 and TGFβ3 are present in high concentrations in human seminal plasma (>100 ng/mL), while TGFβ2 is less abundant. To investigate the physiological significance of each of the three TGFβ isoforms as pro-inflammatory agents in human seminal plasma, we have established in vitro model systems to measure human cervical cell cytokine synthesis. Primary cervical epithelial cells prepared from ectocervix of hysterectomy tissues or transformed Ect1 cells were incubated for 12 h with human recombinant TGFβ (isoforms 1, 2 or 3) or with seminal plasma in the presence or absence of isoform-specific TGFβ neutralising antibodies. Epithelial cell supernatants were recovered 24 h later and supernatants were analysed by commercial ELISA to quantify GM-CSF, IL-6 and IL-8 production. Each of the three TGFβ isoforms mimicked seminal plasma and were comparable in their capacity to stimulate >10-fold increases in both GM-CSF and IL-6 expression in a dose-responsive manner. In contrast, unlike seminal plasma none of the TGFβ isoforms induced IL-8 expression. Addition of neutralising antibodies to TFGβ1, TGFβ2 and TGFβ3 each effected >50% reduction in the ability of seminal plasma to induce GM-CSF and IL-6, but did not impair seminal plasma-stimulated IL-8 production. Together these data show that TGFβ1, TGFβ2 and TGFβ3 are major active constituents of seminal plasma, acting to elicit GM-CSF and IL-6 production in cervical epithelial cells. However, TGFβ does not fully account for the pro-inflammatory effects of human seminal plasma, and other active constituents remain to be identified. (1) D. J. Sharkey et al. (2003) Proc. SRB.

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