Rimonabant (SR141716) induces metabolism and acquisition of fertilizing ability in human sperm

Metabolites assay offers potential solution to improve the rooster semen cryopreservation

Semen cryopreservation represents a promising technology utilized for preserving high-quality chicken varieties in husbandry practices. However, the efficacy of this methodology is significantly impeded by the diminished quality of sperm. Metabolites, as the end products of metabolic reactions, serve as indicators of biological processes and offer insights into physiological conditions. In this study, we investigaged the sperm quality and alteration in metabolic profiles during the cryopreservation of Longyou Partridge Chicken semen. Following artificial semen collection, four groups of semen samples were established based on four points of the cryopreservation process (Ⅰ, fresh semen; Ⅱ, semen added extender and chilled at 4 °C for 30 min; Ⅲ, semen added cryoprotectants; Ⅳ, semen gradient freezed and stored in liquid nitrogen). Semen cryopreservation has a negative effect on the percentage of sperm in a straight-line trajectory (LIN), has no significant effect on total motile sperms (TM) or the proportion of sperm with typical morphology (NM). Metabolites were identified using LC-MS technique and analyses including Principal Component Analysis (PCA), Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA), Univariate statistical analysis, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database were employed to identify metabolites. A total of 2471 metabolites had been identified, with the majority of the list being made up of amino acids and their metabolites as well as benzene and substituted derivatives. Group II exhibits 882 metabolites with significantly elevated abundance relative to Group I, alongside 37 metabolites displaying decreased abundance. In Group III, 836 metabolites demonstrate notably augmented abundance compared to Group II, while 87 metabolites exhibit reduced abundance. Furthermore, Group IV showcases 513 metabolites with markedly heightened abundance in comparison to Group III, and 396 metabolites with decreased abundance. Specific metabolites such as 5-Hydroxylysine, Phosphocholine, and alpha-d-glucose-6-phosphate exhibited a progressive decline during the cryopreservation process, correlating with either dilution and chilling, cryoprotectant addition, or freezing. In conclusion, our investigation systematically examined the changes of seminal metabolome and sperm quality throughout the cryopreservation process of rooster semen.

Comparative Proteomics Elucidates the Potential Mechanism of Sperm Capacitation of Chinese Mitten Crabs (Eriocheir sinensis)

Sperm capacitation is broadly defined as a suite of biochemical and biophysical changes resulting from the acquisition of fertilization ability. To gain insights into the regulation mechanism of crustacean sperm capacitation, 4D label-free quantitative proteomics was first applied to analyze the changes of sperm in Eriocheir sinensis under three sequential physiological conditions: seminal vesicles (X2), hatched with the seminal receptacle content (X3), and incubated with egg water (X5). In total, 1536 proteins were identified, among which 880 proteins were quantified, with 82 and 224 proteins significantly altered after incubation with the seminal receptacle contents and egg water. Most differentially expressed proteins were attributed to biological processes by Gene Ontology annotation analysis. As the fundamental bioenergetic metabolism of sperm, the oxidative phosphorylation, glycolysis, and the pentose phosphate pathway presented significant changes under the treatment of seminal receptacle contents, indicating intensive regulation for sperm in the seminal receptacle. Additionally, the seminal receptacle contents also significantly increased the oxidation level of sperm, whereas the enhancement of abundance in superoxide dismutase, peroxiredoxin 1, and glutathione S-transferase after incubation with egg water significantly improved the resistance against oxidation. These results provided a new perspective for reproduction studies in crustaceans.

Sperm proteostasis: Can-nabinoids be chaperone's partners?

The male gamete is a highly differentiated cell that aims to fuse with the oocyte in fertilization. Sperm have silenced the transcription and translational processes, maintaining proteostasis to guarantee male reproductive health. Despite the information about the implication of molecular chaperones as orchestrators of protein folding or aggregation, and the handling of body homeostasis by the endocannabinoid system, there is still a lack of basic investigation and random controlled clinical trials that deliver more evidence on the involvement of cannabinoids in reproductive function. Besides, we noticed that the information regarding whether recreational marijuana affects male fertility is controversial and requires further investigation. In other cell models, it has recently been evidenced that chaperones and cannabinoids are intimately intertwined. Through a literature review, we aim to explore the interaction between chaperones and cannabinoid signaling in sperm development and function. To untangle how or whether this dialogue happens within the sperm proteostasis. We discuss the action of chaperones, the endocannabinoid system and phytocannabinoids in sperm proteostasis. Reports of some heat shock and lipid proteins interacting with cannabinoid receptors prove that chaperones and the endocannabinoid system are in an intimate dialogue. Meanwhile, advancing the evidence to decipher these mechanisms for introducing innovative interventions into routine clinical settings becomes crucial. We highlight the potential interaction between chaperones and cannabinoid signaling in regulating proteostasis in male reproductive health.

The interplay between kisspeptin and endocannabinoid systems modulates male hypothalamic and gonadic control of reproduction in vivo

Introduction

Male reproduction is under the control of the hypothalamus-pituitary-gonadal (HPG) axis. The endocannabinoid system (ECS) and the kisspeptin system (KS) are two major signaling systems in the central and peripheral control of reproduction, but their possible interaction has been poorly investigated in mammals. This manuscript analyzes their possible reciprocal modulation in the control of the HPG axis.

Materials and methods

Adolescent male rats were treated with kisspeptin-10 (Kp10) and endocannabinoid anandamide (AEA), the latter alone or in combination with the type 1 cannabinoid receptor (CB1) antagonist rimonabant (SR141716A). The hypothalamic KS system and GnRH expression, circulating sex steroids and kisspeptin (Kiss1) levels, and intratesticular KS and ECS were evaluated by immunohistochemical and molecular methods. Non-coding RNAs (i.e., miR145-5p, miR-132-3p, let7a-5p, let7b-5p) were also considered.

Results

Circulating hormonal values were not significantly affected by Kp10 or AEA; in the hypothalamus, Kp10 significantly increased GnRH mRNA and aromatase Cyp19, Kiss1, and Kiss1 receptor (Kiss1R) proteins. By contrast, AEA treatment affected the hypothalamic KS at the protein levels, with opposite effects on the ligand and receptor, and SR141716A was capable of attenuating the AEA effects. Among the considered non-coding RNA, only the expression of miR145-5p was positively affected by AEA but not by Kp10 treatment. Localization of Kiss1+/Kiss1R+ neurons in the arcuate nucleus revealed an increase of Kiss1R-expressing neurons in Kp10- and AEA-treated animals associated with enlargement of the lateral ventricles in Kp10-treated animals. In the brain and testis, the selected non-coding RNA was differently modulated by Kp10 or AEA. Lastly, in the testis, AEA treatment affected the KS at the protein levels, whereas Kp10 affected the intragonadal levels of CB1 and FAAH, the main modulator of the AEA tone. Changes in pubertal transition-related miRNAs and the intratesticular distribution of Kiss1, Kiss1R, CB1, and CB2 following KP and AEA treatment corroborate the KS-ECS crosstalk also showing that the CB1 receptor is involved in this interplay.

Conclusion

For the first time in mammals, we report the modulation of the KS in both the hypothalamus and testis by AEA and revealed the KP-dependent modulation of CB1 and FAAH in the testis. KP involvement in the progression of spermatogenesis is also suggested.

Endocannabinoid system and epigenetics in spermatogenesis and testicular cancer

In mammals, male germ cell development starts during fetal life and is carried out in postnatal life with the formation of sperms. Spermatogenesis is the complex and highly orderly process during which a group of germ stem cells is set at birth, starts to differentiate at puberty. It proceeds through several stages: proliferation, differentiation, and morphogenesis and it is strictly regulated by a complex network of hormonal, autocrine and paracrine factors and it is associated with a unique epigenetic program. Altered epigenetic mechanisms or inability to respond to these factors can impair the correct process of germ development leading to reproductive disorders and/or testicular germ cell cancer. Among factors regulating spermatogenesis an emerging role is played by the endocannabinoid system (ECS). ECS is a complex system comprising endogenous cannabinoids (eCBs), their synthetic and degrading enzymes, and cannabinoid receptors. Mammalian male germ cells have a complete and active ECS which is modulated during spermatogenesis and that crucially regulates processes such as germ cell differentiation and sperm functions. Recently, cannabinoid receptor signaling has been reported to induce epigenetic modifications such as DNA methylation, histone modifications and miRNA expression. Epigenetic modifications may also affect the expression and function of ECS elements, highlighting the establishment of a complex mutual interaction. Here, we describe the developmental origin and differentiation of male germ cells and testicular germ cell tumors (TGCTs) focusing on the interplay between ECS and epigenetic mechanisms involved in these processes.

Oxidative Stress and Male Fertility: Role of Antioxidants and Inositols

Infertility is defined as a couple’s inability to conceive after at least one year of regular unprotected intercourse. This condition has become a global health problem affecting approximately 187 million couples worldwide and about half of the cases are attributable to male factors. Oxidative stress is a common reason for several conditions associated with male infertility. High levels of reactive oxygen species (ROS) impair sperm quality by decreasing motility and increasing the oxidation of DNA, of protein and of lipids. Multi-antioxidant supplementation is considered effective for male fertility parameters due to the synergistic effects of antioxidants. Most of them act by decreasing ROS concentration, thus improving sperm quality. In addition, other natural molecules, myo-inositol (MI) and d-chiro–inositol (DCI), ameliorate sperm quality. In sperm cells, MI is involved in many transduction mechanisms that regulate cytoplasmic calcium levels, capacitation and mitochondrial function. On the other hand, DCI is involved in the downregulation of steroidogenic enzyme aromatase, which produces testosterone. In this review, we analyze the processes involving oxidative stress in male fertility and the mechanisms of action of different molecules.

FSH-R Human Early Male Genital Tract, Testicular Tumors and Sperm: Its Involvement in Testicular Disorders

The follicle-stimulating hormone receptor (FSH-R) expression was always considered human gonad-specific. The receptor has also been newly detected in extragonadal tissues. In this finding, we evaluated FSH-R expression in the human male early genital tract, in testicular tumors, and in sperm from healthy and varicocele patients. In sperm, we also studied the mechanism of FSH-R action. Immunohystochemistry and Western blot analysis showed FSH-R presence in the first pathways of the human genital tract, in embryonal carcinoma, and in sperm, but it was absent in seminoma and in lower varicocele. In sperm, FSH/FSH-R activity is mediated by G proteins activating the PKA pathway, as we observed by using the H89. It emerged that increasing FSH treatments induced motility, survival, capacitation, and acrosome reaction in both sperm samples. The different FSH-R expression in tumor testicular tissues may be discriminate by tumor histological type. In spermatozoa, FSH-R indicates a direct action of FSH in these cells, which could be beneficial during semen preparation for in vitro fertilization procedures. For instance, FSH positive effects could be relevant in idiopathic infertility and in the clinic surgery of varicocele. In conclusion, FSH-R expression may be considered a molecular marker of testicular disorders.

Cannabinoid signalling and effects of cannabis on the male reproductive system

Marijuana is the most widely consumed recreational drug worldwide, which raises concerns for its potential effects on fertility. Many aspects of human male reproduction can be modulated by cannabis-derived extracts (cannabinoids) and their endogenous counterparts, known as endocannabinoids (eCBs). These latter molecules act as critical signals in a variety of physiological processes through receptors, enzymes and transporters collectively termed the endocannabinoid system (ECS). Increasing evidence suggests a role for eCBs, as well as cannabinoids, in various aspects of male sexual and reproductive health. Although preclinical studies have clearly shown that ECS is involved in negative modulation of testosterone secretion by acting both at central and testicular levels in animal models, the effect of in vivo exposure to cannabinoids on spermatogenesis remains a matter of debate. Furthermore, inconclusive clinical evidence does not seem to support the notion that plant-derived cannabinoids have harmful effects on human sexual and reproductive health. An improved understanding of the complex crosstalk between cannabinoids and eCBs is required before targeting of ECS for modulation of human fertility becomes a reality.

Sperm performance in oligoasthenoteratozoospermic patients is induced by a nutraceuticals mix, containing mainly myo-inositol

The action of myo-inositol (MI), belonging to the inositol family, has been shown to improve sperm quality. To further elucidate the efficacy of this substance in male fertility, we investigated in vivo the effects of a nutraceuticals mix, containing mainly myo-inositol (MI) and in vitro the action of the MI on human male gamete performance. Sperm samples were evaluated from 51 men: 21 healthy normozoospermic and 30 oligoasthenoteratozoospermic (OAT). In the latter group, 15 patients were orally treated with the nutraceutical mix and in the remaining 15 patients only MI was used directly on their ejaculated sperm. Comparing the pathologic samples with respect to normal samples we observed that motility, viability, Bcl-2 phosphorylation, and cholesterol efflux increased after in vitro and in vivo treatments. Glucose-6-phosphate dehydrogenase activity as well as triglycerides level and lipase activity highlighted an enhancement of energy expenditure upon the treatment. Uncapacitated sperm is characterized by an anabolic metabolism, to generate an energy reservoir which will be spent during the capacitation, an energy-consuming process needed to acquire the competence for the fertilization. Intriguingly, our finding highlights that the treatment with these substances facilitated the switch from uncapacitated to capacitated sperm, promoting the acquisition of the male gamete fertilizing capacity. Our data suggested that these substances act both directly on sperm and on spermatogenesis, improving the performance of OAT sperm invitro and invivo. The positive effects of these treatments could be of great help for men and couples who have difficulty to conceive achild in anatural way and/or during medical-assisted reproduction.Abbreviations: 30 OAT-untreated patients; B: 15 OAT patients treated in vivo; Bovine serum albumin (BSA); C: 15 OAT patients treated in vitro; cholesterol oxidase-peroxidase (CHOD-POD); H: Normozoospermic samples; HM: sperm from normospermic patients treated in vitro with MI; MI: Myoinositol: IM: Immobile motility; NP: Non-progressive motility; OAT: Oligoasthenoteratozoospermic; PPP: Pentose Phosphate Pathway; PR: Progressive motility; WHO: World Health Organization.

Human Sperm Express the Receptor for Glucagon-like Peptide-1 (GLP-1), Which Affects Sperm Function and Metabolism

AIM

Glucagon-like peptide-1 (GLP-1) produces pleiotropic effects binding to the GLP-1 receptor (GLP1-R), potentiating insulin secretion in the pancreas. GLP1-R is expressed in peripheral tissues and evidence for its role in reproduction has come from knockout mice, although the relationship between GLP-1 and male fertility needs to be clarified. Given that human sperm is an insulin-sensitive and insulin-secreting cell, we hypothesized that the GLP-1/GLP1-R axis may be expressed and functional in these cells.

RESULTS AND DISCUSSION

We revealed the presence of GLP1-R by Western blotting and immunofluorescence analyses. Because Exendin-4 (Ex-4) displays similar functional properties to native GLP-1, we used this agonist to perform a dose-response study on progressive motility and cholesterol efflux, showing that 300 pM Ex-4 was the most effective treatment. These actions are mediated by GLP1-R and independent from sperm-secreted insulin. The exposure to Ex-4 fueled phosphatidylinositol-3-kinase (PI3K)/AKT signaling and was reversed by H89, indicating a protein kinase A (PKA)-dependence of GLP-1/GLP1-R signaling. It emerged that in sperm, insulin secretion regulated by Ex-4 did not occur in a strictly glucose-dependent manner. A stimulatory action of Ex-4/GLP1-R on lactate dehydrogenase and glucose-6-phosphate dehydrogenase (G6PDH) activities was observed. Ex-4/GLP1-R decreased triglycerides content concomitantly to enhanced lipase and acyl-coenzyme A (acyl-CoA) dehydrogenase activities, addressing a lipolytic effect.

CONCLUSION

Collectively, we discovered that human sperm is a new GLP1 incretin target, broadening our knowledge about the effects of the GLP1-R agonist in the male reproductive field. Further findings in humans should be conducted in the future to confirm it and to improve the translational aspect of this study.

Evaluation of cannabinoid receptors Type 1 and Type 2 mRNA expression in mature versus immature spermatozoa from fertile and infertile males

The expression of the main cannabinoid receptors (CBR1 and CBR2) was investigated to evaluate the possible association with the sperm maturation from fertile and infertile individuals. One hundred subjects were classified into fertile (n = 50) and infertile groups (n = 50). Fresh semen samples were collected. Computer-assisted semen analysis and acrosin activity test were done. RNA was extracted from mature and immature sperm pellets. Reverse transcriptase reaction and real-time PCR were done to assess the levels of both CBR1 and CBR2 genes expression in all samples. Mature spermatozoa from both groups showed significantly higher levels of both CBR1 and CBR2 compared with the immature spermatozoa (p < .05). This increment was significantly more important in the fertile group (p < .05). In mature spermatozoa, CBR1 expression was significantly related to variation in sperm morphology, and CBR2 was significantly related to both sperm morphology and linearity index. In conclusion, CBR1 and CBR2 mRNA expression may closely direct the sperm maturation at different steps of the reproductive process.

Cannabinoid Receptors Signaling in the Development, Epigenetics, and Tumours of Male Germ Cells

Endocannabinoids are natural lipid molecules whose levels are regulated by specific biosynthetic and degradative enzymes. They bind to and activate two main cannabinoid receptors type 1 (CB₁) and type 2 (CB₂), and together with their metabolizing enzymes form the “endocannabinoid system” (ECS). In the last years, the relevance of endocannabinoids (eCBs) as critical modulators in various aspects of male reproduction has been pointed out. Mammalian male germ cells, from mitotic to haploid stage, have a complete ECS which is modulated during spermatogenesis. Compelling evidence indicate that in the testis an appropriate “eCBs tone”, associated to a balanced CB receptors signaling, is critical for spermatogenesis and for the formation of mature and fertilizing spermatozoa. Any alteration of this system negatively affects male reproduction, from germ cell differentiation to sperm functions, and might have also an impact on testicular tumours. Indeed, most of testicular tumours develop during early germ-cell development in which a maturation arrest is thought to be the first key event leading to malignant transformation. Considering the ever-growing number and complexity of the data on ECS, this review focuses on the role of cannabinoid receptors CB₁ and CB₂ signaling in male germ cells development from gonocyte up to mature spermatozoa and in the induction of epigenetic alterations in these cells which might be transmitted to the progeny. Furthermore, we present new evidence on their relevance in testicular cancer.

Marijuana use and its influence on sperm morphology and motility: identified risk for fertility among Jamaican men

BACKGROUND

The growing international movement legislating medical marijuana has brought renewed interest to the role of marijuana smoking on fertility potential. Although studies have identified that sperm quality can be compromised by marijuana use, little focus has been placed specifically on those trying to conceive. In this study, we aimed to clarify the impact of marijuana use in semen quality in men being investigated for assisted reproduction.

MATERIALS AND METHODS

We conducted a cross-sectional study at a university-based facility in Jamaica. Routine semen analyses were performed on 229 men ages 23-72 years who were new clients. Logistic regression analyses were performed in order to independently predict quantifiable measures of the impact of marijuana use. The main outcome measures were sperm motility, total motile spermatozoa and morphology.

RESULTS

Overall, 47% of the participants reported marijuana use with 21% of these men reporting recent use. Regression analyses showed that recent use and users of large quantities of marijuana were 2.6 times (aOR = 2.6; 95% CI, 1.0-6.8, p = 0.044) and 4.3 times (aOR = 4.3; 95% CI, 1.1-15.9, p = 0.030) at greater risk of being diagnosed with abnormal motility (asthenozoospermia). Additionally, moderate quantity users were 3.4 times (aOR = 3.4; 95% CI, 1.5-7.9, p = 0.004) more likely to be diagnosed with abnormal morphology (teratozoospermia).

DISCUSSION AND CONCLUSION

Recent use of marijuana as well as moderate to large quantities had an impact on sperm motility and morphology in men being investigated for infertility. We recommend therefore that men undergoing fertility investigations be routinely asked about their recreational use of marijuana and in particular recent and heavy users counselled to stop.

Targeting Peripheral CB1 Receptors Reduces Ethanol Intake via a Gut-Brain Axis

Endocannabinoids acting on the cannabinoid-1 receptor (CB₁R) or ghrelin acting on its receptor (GHS-R_1A) both promote alcohol-seeking behavior, but an interaction between the two signaling systems has not been explored. Here, we report that the peripheral CB₁R inverse agonist JD5037 reduces ethanol drinking in wild-type mice but not in mice lacking CB₁R, ghrelin peptide or GHS-R_1A. JD5037 treatment of alcohol-drinking mice inhibits the formation of biologically active octanoyl-ghrelin without affecting its inactive precursor desacyl-ghrelin. In ghrelin-producing stomach cells, JD5037 reduced the level of the substrate octanoyl-carnitine generated from palmitoyl-carnitine by increasing fatty acid β-oxidation. Blocking gastric vagal afferents abrogated the ability of either CB₁R or GHS-R_1A blockade to reduce ethanol drinking. We conclude that blocking CB₁R in ghrelin-producing cells reduces alcohol drinking by inhibiting the formation of active ghrelin and its signaling via gastric vagal afferents. Thus, peripheral CB₁R blockade may have therapeutic potential in the treatment of alcoholism.

Effect of chronic THC administration in the reproductive organs of male mice, spermatozoa and in vitro fertilization

The increased use of cannabis as a therapeutic drug in recent years has raised some concerns due to its potential effects on reproductive health. With regards to the male, the endocannabinoid system is involved in the spermatogenesis and in the sperm function. The chronic use of tetrahidrocannabinol (THC) has been associated with sperm anomalies, decreased sperm motility and structural changes in the testis. However, whether THC affects sperms ability to fertilize and to generate embryos remains unclear. The aim of this study was to evaluate this effect using a mice model of THC chronic treatment. For this purpose, a chronic treatment with THC was carried out. Mice were randomly allocated into two groups: an experimental group treated with a daily dose of 10 mg/kg-body weight THC for a period of 30 days and a control group treated with a vehicle. The THC-mice cortex showed a significant decrease of mRNA of Cnr1 compared to control-mice while, in the testis, the expression of Cnr1 was not affected. The weight of testis and epididymis and the histological analysis did not show any change between groups. On the other hand, no changes were observed in the sperm motility or the sperm concentration. The chronic use of THC did not generate any methylation change in the three CpG regions of Cnn1 analysed, neither in the brain nor in the embryos generated by in vitro fertilization (IVF). Finally, the embryo production by IVF was no different using spermatozoa from both THC and control mice. This work contradicts the belief that THC consumption has a negative effect on male reproductive processes.

Cannabinoid receptor type-1: breaking the dogmas

The endocannabinoid system (ECS) is abundantly expressed in the brain. This system regulates a plethora of physiological functions and is composed of cannabinoid receptors, their endogenous ligands (endocannabinoids), and the enzymes involved in the metabolism of endocannabinoids. In this review, we highlight the new advances in cannabinoid signaling, focusing on a key component of the ECS, the type-1 cannabinoid receptor (CB ₁). In recent years, the development of new imaging and molecular tools has demonstrated that this receptor can be distributed in many cell types (e.g., neuronal or glial cells) and intracellular compartments (e.g., mitochondria). Interestingly, cellular and molecular effects are differentially mediated by CB ₁ receptors according to their specific localization (e.g., glutamatergic or GABAergic neurons). Moreover, this receptor is expressed in the periphery, where it can modulate periphery-brain connections. Finally, the better understanding of the CB ₁ receptor structure led researchers to propose interesting and new allosteric modulators. Thus, the advances and the new directions of the CB ₁ receptor field will provide new insights and better approaches to profit from its interesting therapeutic profile.

Survival of glucose phosphate isomerase null somatic cells and germ cells in adult mouse chimaeras

The mouse Gpi1 gene encodes the glycolytic enzyme glucose phosphate isomerase. Homozygous Gpi1(-/-) null mouse embryos die but a previous study showed that some homozygous Gpi1(-/-) null cells survived when combined with wild-type cells in fetal chimaeras. One adult female Gpi1(-/-)↔Gpi1(c/c) chimaera with functional Gpi1(-/-) null oocytes was also identified in a preliminary study. The aims were to characterise the survival of Gpi1(-/-) null cells in adult Gpi1(-/-)↔Gpi1(c/c) chimaeras and determine if Gpi1(-/-) null germ cells are functional. Analysis of adult Gpi1(-/-)↔Gpi1(c/c) chimaeras with pigment and a reiterated transgenic lineage marker showed that low numbers of homozygous Gpi1(-/-) null cells could survive in many tissues of adult chimaeras, including oocytes. Breeding experiments confirmed that Gpi1(-/-) null oocytes in one female Gpi1(-/-)↔Gpi1(c/c) chimaera were functional and provided preliminary evidence that one male putative Gpi1(-/-)↔Gpi1(c/c) chimaera produced functional spermatozoa from homozygous Gpi1(-/-) null germ cells. Although the male chimaera was almost certainly Gpi1(-/-)↔Gpi1(c/c), this part of the study is considered preliminary because only blood was typed for GPI. Gpi1(-/-) null germ cells should survive in a chimaeric testis if they are supported by wild-type Sertoli cells. It is also feasible that spermatozoa could bypass a block at GPI, but not blocks at some later steps in glycolysis, by using fructose, rather than glucose, as the substrate for glycolysis. Although chimaera analysis proved inefficient for studying the fate of Gpi1(-/-) null germ cells, it successfully identified functional Gpi1(-/-) null oocytes and revealed that some Gpi1(-/-) null cells could survive in many adult tissues.

Marijuana, phytocannabinoids, the endocannabinoid system, and male fertility

Marijuana has the highest consumption rate among all of the illicit drugs used in the USA, and its popularity as both a recreational and medicinal drug is increasing especially among men of reproductive age. Male factor infertility is on the increase, and the exposure to the cannabinoid compounds released by marijuana could be a contributing cause. The endocannabinoid system (ECS) is deeply involved in the complex regulation of male reproduction through the endogenous release of endocannabinoids and binding to cannabinoid receptors. Disturbing the delicate balance of the ECS due to marijuana use can negatively impact reproductive potential. Various in vivo and in vitro studies have reported on the empirical role that marijuana plays in disrupting the hypothalamus-pituitary-gonadal axis, spermatogenesis, and sperm function such as motility, capacitation, and the acrosome reaction. In this review, we highlight the latest evidence regarding the effect of marijuana use on male fertility and also provide a detailed insight into the ECS and its significance in the male reproductive system.

Human sperm liver receptor homolog-1 (LRH-1) acts as a downstream target of the estrogen signaling pathway

In the last decade, the study of human sperm anatomy, at molecular level, has revealed the presence of several nuclear protein receptors. In this work, we examined the expression profile and the ultrastructural localization of liver receptor homolog-1 (LRH-1) in human spermatozoa. We evidenced the presence of the receptor by Western blotting and real time-RT-PCR. Furthermore, we used immunogold electron microscopy to investigate the sperm anatomical regions containing LRH-1. The receptor was mainly located in the sperm head, whereas its expression was reduced in the neck and across the tail. Interestingly, we observed the presence of LRH-1 in different stages of testicular germ cell development by immunohistochemistry. In somatic cells, it has been suggested that the LRH-1 pathway is tightly linked with estrogen signaling and the important role of estradiol has been widely studied in sperm cells. To assess the significance of LRH-1 in male gametes and to deepen understanding of the role of estrogens in these cells, we investigated important sperm features such as motility, survival and capacitation. Spermatozoa were treated with 10 nm estradiol and the inhibition of LRH-1 reversed the estradiol stimulatory action. From our data, we discovered that human spermatozoa can be considered a new site of expression for LRH-1, evidencing its role in sperm motility, survival and cholesterol efflux. Furthermore, we may presume that in spermatozoa the LRH-1 effects are closely integrated with the estrogen signaling, supporting LRH-1 as a downstream effector of the estradiol pathway on some sperm functions.

Relationship between seminal plasma levels of anandamide congeners palmitoylethanolamide and oleoylethanolamide and semen quality

OBJECTIVE

To determine whether changes in seminal plasma concentrations of the endogenous lipid signaling molecules palmitoylethanolamide (PEA) and oleoylethanolamide (OEA) have significant effects on sperm quality.

DESIGN

Biochemical and physiological studies of human seminal plasma and spermatozoa.

SETTING

Academic tertiary care medical center.

PATIENT(S)

Ninety men attending an infertility clinic for semen analysis.

INTERVENTION(S)

Palmitoylethanolamide and OEA extracted from seminal plasma were quantified by ultra high-performance liquid chromatography (HPLC)-tandem mass spectrometry. Patient sperm from semen with normal parameters were exposed in vitro to PEA or OEA to determine effects on sperm motility, viability, and mitochondrial activity.

MAIN OUTCOME MEASURE(S)

The relationship between seminal plasma concentrations of PEA and OEA and sperm quality and the effect of these compounds on sperm motility, viability, and mitochondria activity in vitro.

RESULT(S)

Palmitoylethanolamide and OEA concentrations in seminal plasma were lower in men with asthenozoospermia and oligoasthenoteratozospermia compared with men with normal semen parameters. Palmitoylethanolamide and OEA rapidly and significantly improved sperm motility and maintained viability without affecting mitochondria activity in vitro.

CONCLUSION(S)

Maintenance of normal PEA and OEA tone in human seminal plasma may be necessary for the preservation of normal sperm function and male fertility. Exocannabinoids found in Cannabis, such as delta-9-tetrahydrocannabinol and cannabidiol, could compete with these endocannabinoids upsetting their finely balanced, normal functioning and resulting in male reproductive failure.

Fenitrothion action at the endocannabinoid system leading to spermatotoxicity in Wistar rats

Organophosphate (OP) compounds as anticholinesterase agents may secondarily act on diverse serine hydrolase targets, revealing unfavorable physiological effects including male reproductive toxicity. The present investigation proposes that fenitrothion (FNT, a major OP compound) acts on the endocannabinoid signaling system in male reproductive organs, thereby leading to spermatotoxicity (sperm deformity, underdevelopment, and reduced motility) in rats. FNT oxon (bioactive metabolite of FNT) preferentially inhibited the fatty acid amide hydrolase (FAAH), an endocannabinoid anandamide (AEA) hydrolase, in the rat cellular membrane preparation from the testis in vitro. Subsequently, male Wistar rats were treated orally with 5 or 10mg/kg FNT for 9 weeks and the subchronic exposure unambiguously deteriorated sperm motility and morphology. The activity-based protein profiling analysis with a phosphonofluoridate fluorescent probe revealed that FAAH was selectively inhibited among the FNT-treated cellular membrane proteome in testis. Intriguingly, testicular AEA (endogenous substrate of FAAH) levels were elevated along with the FAAH inhibition caused by the subchronic exposure. More importantly, linear regression analyses for the FNT-elicited spermatotoxicity reveal a good correlation between the testicular FAAH activity and morphological indices or sperm motility. Accordingly, the present study proposes that the FNT-elicited spermatotoxicity appears to be related to inhibition of FAAH leading to overstimulation of the endocannabinoid signaling system, which plays crucial roles in spermatogenesis and sperm motility acquirement.

Endocannabinoids as biomarkers of human reproduction

BACKGROUND

Infertility is a condition of the reproductive system that affects ∼10-15% of couples attempting to conceive a baby. More than half of all cases of infertility are a result of female conditions, while the remaining cases can be attributed to male factors, or to a combination of both. The search for suitable biomarkers of pregnancy outcome is a challenging issue in human reproduction, aimed at identifying molecules with predictive significance of the reproductive potential of male and female gametes. Among the various candidates, endocannabinoids (eCBs), and in particular anandamide (AEA), represent potential biomarkers of human fertility disturbances. Any perturbation of the balance between synthesis and degradation of eCBs will result in local changes of their tone in human female and male reproductive tracts, which in turn regulates various pathophysiological processes, oocyte and sperm maturation included.

METHODS

PubMed and Web of Science databases were searched for papers using relevant keywords like 'biomarker', 'endocannabinoid', 'infertility', 'pregnancy' and 'reproduction'.

RESULTS

In this review, we discuss different studies on the measurements of AEA and related eCBs in human reproductive cells, tissues and fluids, where the local contribution of these bioactive lipids could be critical in ensuring normal sperm fertilizing ability and pregnancy.

CONCLUSION

Based on the available data, we suggest that the AEA tone has the potential to be exploited as a novel diagnostic biomarker of infertility, to be used in association with assays of conventional hormones (e.g. progesterone, β-chorionic gonadotrophin) and semen analysis. However further quantitative research of its predictive capacity is required.

Updates in reproduction coming from the endocannabinoid system

The endocannabinoid system (ECS) is an evolutionarily conserved master system deeply involved in the central and local control of reproductive functions in both sexes. The tone of these lipid mediators-deeply modulated by the activity of biosynthetic and hydrolyzing machineries-regulates reproductive functions from gonadotropin discharge and steroid biosynthesis to the formation of high quality gametes and successful pregnancy. This review provides an overview on ECS and reproduction and focuses on the insights in the regulation of endocannabinoid production by steroids, in the regulation of male reproductive activity, and in placentation and parturition. Taken all together, evidences emerge that the activity of the ECS is crucial for procreation and may represent a target for the therapeutic exploitation of infertility.

A potential target for organophosphate insecticides leading to spermatotoxicity

Organophosphate (OP) insecticides as an anticholinesterase also act on the diverse serine hydrolase targets, thereby revealing secondary or unexpected toxic effects including male reproductive toxicity. The present investigation detects a possible target molecule(s) for OP-induced spermatotoxicity (sperm deformity, underdevelopment, and reduced motility) from a chemical standpoint. The activity-based protein profiling (ABPP) approach with a phosphonofluoridate fluorescent probe pinpointed the molecular target for fenitrothion (FNT, a major OP insecticide) oxon (bioactive metabolite of FNT) in the mouse testicular membrane proteome, i.e., FNT oxon phosphorylates the fatty acid amide hydrolase (FAAH), which plays pivotal roles in spermatogenesis and sperm motility acquirement. Subsequently, mice were treated orally with vehicle or FNT for 10 days, and FAAH activity in testis or epididymis cauda was markedly reduced by the subacute exposure. ABPP analysis revealed that FAAH was selectively inhibited among the FNT-treated testicular membrane proteome. Accordingly, FAAH is a potential target for OP-elicited spermatotoxicity.

Δ9-Tetrahydrocannabinol (Δ9-THC) attenuates mouse sperm motility and male fecundity

BACKGROUND AND PURPOSE

Numerous studies have shown that N-arachidonoylethanolamine (AEA) can inhibit sperm motility and function but the ability of cannabinoids to inhibit sperm motility is not well understood. We investigated the effects of WIN 55,212-2, a CB(1) cannabinoid receptor agonist, and Δ(9) -tetrahydracannabinol (Δ(9) -THC) on the ATP levels and motility of murine sperm in vitro. In addition, the effects of acute administration of Δ(9) -THC on male fecundity were determined.

EXPERIMENTAL APPROACH

Effects of Δ(9) -THC on basal sperm kinematics were determined using computer-assisted sperm analysis (CASA). Stop-motion imaging was performed to measure sperm beat frequency. The effect of Δ(9) -THC on sperm ATP was determined using a luciferase assay. Male fertility was determined by evaluating the size of litters sired by Δ(9) -THC-treated males. KEY RESULTS Pretreatment of sperm for 15 min with 1 µM Δ(9) -THC reduced their basal motility and attenuated the ability of bicarbonate to stimulate flagellar beat frequency. Treatment with 5 µM WIN 55,212-2 or 10 µM Δ(9) -THC for 30 min reduced sperm ATP levels. In sperm lacking CB(1) receptors this inhibitory effect of WIN 55,212-2 on ATP was attenuated whereas that of Δ(9) -THC persisted. Administration of 50 mg·kg(-1) Δ(9) -THC to male mice just before mating caused a 20% decrease in embryonic litter size.

CONCLUSIONS AND IMPLICATIONS

Δ(9) -THC inhibits both basal and bicarbonate-stimulated sperm motility in vitro and reduces male fertility in vivo. High concentrations of WIN 55,212-2 or Δ(9) -THC inhibit ATP production in sperm; this effect of WIN 55,212-2 is CB(1) receptor-dependent whereas that of Δ(9) -THC is not. LINKED ARTICLES This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-8. To view Part I of Cannabinoids in Biology and Medicine visit http://dx.doi.org/10.1111/bph.2011.163.issue-7.

Rimonabant reduces keratinocyte viability by induction of apoptosis and exerts topical anti-inflammatory activity in mice

BACKGROUND AND PURPOSE

There is growing evidence that the cannabinoid CB(1) receptor antagonist, rimonabant (SR141716) exerts potential anti-proliferative and anti-inflammatory actions. Here, we have assessed the effects of rimonabant in vitro in murine immortalized keratinocytes and in vivo by assaying the topical anti-inflammatory activity.

EXPERIMENTAL APPROACH

Cell viability and death in a keratinocyte cell line (C5N cells) were measured by Trypan blue exclusion assay and cytotoxicity by sulphorhodamine B test. Cell cycle progression was assessed by flow cytometry and the expression of apoptotic and anti-apoptotic markers, cyclins, pathways of signal transduction and CB1 receptor levels were evaluated by Western blot. The topical anti-inflammatory properties of rimonabant were analysed by inhibition of croton oil-induced ear dermatitis in mice.

KEY RESULTS

Rimonabant reduced cell viability and induced apoptosis as shown by the enhanced number of cells in the subG0 phase of the cell cycle, the expression of Bax and reduced levels of Bcl-2 and X-inhibitor of apoptosis protein. In addition, reduced levels of phosphorylated serine/threonine protein kinase Akt and nuclear factor-kappa B were detected associated with regulation of total nuclear factor-kappa B and inhibitor of kappa B-α, phosphorylated inhibitor of kappa B-α, cyclins D1, E and A. In croton oil-induced ear dermatitis, rimonabant significantly reduced oedema and leukocyte infiltrate.

CONCLUSIONS AND IMPLICATIONS

Rimonabant reduced cell viability, inducing cell death in keratinocytes and decreased croton oil-induced ear dermatitis. Our findings suggest a potential application of rimonabant as a topical anti-inflammatory drug. We did not assess the involvement of CB(1) receptors in these effects of rimonabant.

Effects of endocannabinoid 1 and 2 (CB1; CB2) receptor agonists on luteal weight, circulating progesterone, luteal mRNA for luteinizing hormone (LH) receptors, and luteal unoccupied and occupied receptors for LH in vivo in ewes

Thirty to forty percent of ruminant pregnancies are lost during the first third of gestation due to inadequate progesterone secretion. During the estrous cycle, luteinizing hormone (LH) regulates progesterone secretion by small luteal cells (SLC). Loss of luteal progesterone secretion during the estrous cycle is increased via uterine secretion of prostaglandin F(2α) (PGF(2α)) starting on days 12-13 post-estrus in ewes with up to 4-6 pulses per day. Prostaglandin F(2α) is synthesized from arachidonic acid, which is released from phospholipids by phospholipase A2. Endocannabinoids are also derived from phospholipids and are associated with infertility. Endocannabinoid-induced infertility has been postulated to occur primarily via negative effects on implantation. Cannabinoid (CB) type 1 (CB1) or type 2 (CB2) receptor agonists and an inhibitor of the enzyme fatty acid amide hydrolase, which catabolizes endocannabinoids, decreased luteal progesterone, prostaglandin E (PGE), and prostaglandin F(2α) (PGF(2α)) secretion by the bovine corpus luteum in vitro by 30 percent. The objective of the experiment described herein was to determine whether CB1 or CB2 receptor agonists given in vivo affect circulating progesterone, luteal weights, luteal mRNA for LH receptors, and luteal occupied and unoccupied LH receptors during the estrous cycle of ewes. Treatments were: Vehicle, Methanandamide (CB1 agonist; METH), or 1-(4-chlorobenzoyl)-5-methoxy-1H-indole-3-acetic acid morpholineamide (CB2 agonist; IMMA). Ewes received randomized treatments on day 10 post-estrus. A single treatment (500 μg; N=5/treatment group) in a volume of 1 ml was given into the interstitial tissue of the ovarian vascular pedicle adjacent to the luteal-containing ovary. Jugular venous blood was collected at 0 h and every 6-48 h for the analysis of progesterone by radioimmunoassay (RIA). Corpora lutea were collected at 48 h, weighed, bisected, and frozen in liquid nitrogen until analysis of unoccupied and occupied LH receptors and mRNA for LH receptors. Profiles of jugular venous progesterone, luteal weights, luteal mRNA for LH receptors, and luteal occupied and unoccupied LH receptors were decreased (P≤0.05) by CB1 or CB2 receptor agonists when compared to Vehicle controls. Progesterone in 80 percent of CB1 or CB2 receptor agonist-treated ewes was decreased (P≤0.05) below 1 ng/ml by 48 h post-treatment. It is concluded that the stimulation of either CB1 or CB2 receptors in vivo affected negatively luteal progesterone secretion by decreasing luteal mRNA for LH receptors and also decreasing occupied and unoccupied receptors for LH on luteal membranes. The corpus luteum may be an important site for endocannabinoids to decrease fertility as well as negatively affect implantation, since progesterone is required for implantation.

From Fertilisation to Implantation in Mammalian Pregnancy-Modulation of Early Human Reproduction by the Endocannabinoid System

There is an increasing recognition that the endocannabinoid system is the crucial cytokine-hormone system regulating early human pregnancy. The synchronous development of the fertilized embryo and the endometrium to ensure timely implantation has been shown to be one of the pivotal steps to successful implantation. This development is thought to be regulated by a finely balanced relationship between various components of the endocannabinoid system in the endometrium, the embryo and the Fallopian tube. In addition, this system has also been shown to be involved in the regulation of the development and maturation of the gametes prior to fertilization. In this review, we will examine the evidence from animal and human studies to support the role of the endocannabinoid system in gametogenesis, fertilization, implantation, early pregnancy maintenance, and in immunomodulation of pregnancy. We will discuss the role of the cannabinoid receptors and the enzymes involved in the synthesis and degradation of the key endocannabinoid ligands (e.g., anandamide and 2-arachinoylglycerol) in early reproduction.