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BackgroundSeminal oxidative stress has been shown to be a key factor in the development of male infertility. However, the benefits of infertility treatments with antioxidants such as coenzyme Q10 (CoQ10) remains controversial.ObjectivesThe aim of the present study was to assess the effects of CoQ10 supplementation on semen quality, i.e., semen volume, total sperm number, sperm concentration, total sperm motility, percentage of progressive sperm motility and sperm morphology. In addition, the effects of CoQ10 supplementation on circulating testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and inhibin B levels were evaluated.DesignA systematic review and a meta-analysis of randomized controlled trials (RCTs) were performed to assess the effects of CoQ10 supplementation on semen quality and serum levels of male reproductive hormones.MethodsWe conducted a strategic literature search in the Cochrane, EMBASE, PubMed/MEDLINE, Scopus, and Web of Science databases and collected only RCTs. The data in the collected RCTs were then meta-analyzed according to PRISMA guidelines.ResultsOut of 2,144 collected studies, only eight were classified eligible. The studies included a total of 877 male subjects; 462 CoQ10-treated and 415 untreated/placebo-treated. We found significantly higher total sperm counts (SMD -13.38 [95% CI: −16.33, −10.43] P< 0.0001), total (SMD -7.26 [95% CI: −10.15, −4.36] P< 0.00001) and progressive motility (SMD -6.386 [95% CI: −10.04, −2.73] P= 0.0006), and normally formed sperm (SMD -1.96 [95% CI: −3.29, −0.62] P= 0.004) in CoQ10-treated male subjects compared with untreated/placebo-treated male subjects. Nonetheless, there was a significant inter-study heterogeneity in these studies. Moreover, significantly higher serum testosterone (SMD -0.59 [95% CI: −0.79, −0.40] P< 0.00001) and inhibin B levels (SMD -0.92 [95% CI: −1.47, −0.37] P= 0.001) were recorded in CoQ10-treated subjects compared to untreated/placebo-treated subjects. In addition, CoQ10 supplementation significantly lowered serum LH (SMD 1.77 [95% CI: 1.26, 2.28] P< 0.00001) and FSH concentrations (SMD 1.60 [95% CI: 1.38, 1.81] P< 0.00001). Interestingly, there was no significant inter-study heterogeneity in the hormonal studies. However, CoQ10 supplementation had no significant effect on semen volume (SMD 0.12 [95% CI: −0.13, 0.37] P= 0.34) and sperm concentration (SMD -6.69 [95% CI: −16.28, 2.90] P= 0.17).ConclusionOur study shows that CoQ10 supplementation increases total sperm count, total and progressive sperm motility, and the proportion of normally formed sperm in association with higher serum testosterone and inhibin B levels. Our study therefore supports the view in the literature of a beneficial use of CoQ10 in male infertility treatment. However, further well-designed RCTs with sufficiently large numbers of subjects are required to reach a final conclusion.

During the past decades, several endocrine disrupting chemicals (EDCs) have been confirmed to affect male reproductive function and fertility in animal studies. EDCs are suspected to exert similar effects in humans, based on strong associations between levels of antiandrogenic EDCs in pregnant women and adverse reproductive effects in infants. Testicular macrophages (tMΦ) play a vital role in modulating immunological privilege and maintaining normal testicular homeostasis as well as fetal development. Although tMΦ were not historically studied in the context of endocrine disruption, they have emerged as potential targets to consider due to their critical role in regulating cells such as spermatogonial stem cells (SSCs) and Leydig cells. Few studies have examined the impact of EDCs on the ability of testicular cells to communicate and regulate each other’s functions. In this review, we recapitulate what is known about tMΦ functions and interactions with other cell types in the testis that support spermatogenesis and steroidogenesis. We also surveyed the literature for reports on the effects of the EDCs genistein and DEHP on tMΦ, SSCs, Sertoli and Leydig cells. Our goal is to explore the possibility that EDC disruption of tMΦ interactions with other cell types may play a role in their adverse effects on testicular developmental programming and functions. This approach will highlight gaps of knowledge, which, once resolved, should improve the risk assessment of EDC exposure and the development of safeguards to protect male reproductive functions.

Sertoli cells play essential roles in male reproduction, from supporting fetal testis development to nurturing male germ cells from fetal life to adulthood. Dysregulating Sertoli cell functions can have lifelong adverse effects by jeopardizing early processes such as testis organogenesis, and long-lasting processes such as spermatogenesis. Exposure to endocrine disrupting chemicals (EDCs) is recognized as contributing to the rising incidence of male reproductive disorders and decreasing sperm counts and quality in humans. Some drugs also act as endocrine disruptors by exerting off-target effects on endocrine tissues. However, the mechanisms of toxicity of these compounds on male reproduction at doses compatible with human exposure are still not fully resolved, especially in the case of mixtures, which remain understudied. This review presents first an overview of the mechanisms regulating Sertoli cell development, maintenance, and functions, and then surveys what is known on the impact of EDCs and drugs on immature Sertoli cells, including individual compounds and mixtures, and pinpointing at knowledge gaps. Performing more studies on the impact of mixtures of EDCs and drugs at all ages is crucial to fully understand the adverse outcomes these chemicals may induce on the reproductive system.

Sertoli cells are essential for germ cell development and function. Their disruption by endocrine disrupting chemicals (EDCs) or drugs could jeopardize spermatogenesis, contributing to male infertility. Perinatal exposure to EDCs and acetaminophen (APAP) disrupts male reproductive functions in animals and humans. Infants can be exposed simultaneously to the dietary soy phytoestrogen genistein (GEN) and APAP used for fever or pain relief. Our goal was to determine the effects of 10–100 µM APAP and GEN, alone or mixed, on immature Sertoli cells using mouse TM4 Sertoli cell line and postnatal-day 8 rat Sertoli cells, by measuring cell viability, proliferation, prostaglandins, genes and protein expression, and functional pathways. A value of 50 µM APAP decreased the viability, while 100 µM APAP and GEN decreased the proliferation. Sertoli cell and eicosanoid pathway genes were affected by GEN and mixtures, with downregulation of Sox9, Cox1, Cox2, and genes relevant for Sertoli cell function, while genes involved in inflammation were increased. RNA-seq analysis identified p53 and TNF signaling pathways as common targets of GEN and GEN mixture in both cell types. These results suggest that APAP and GEN dysregulate immature Sertoli cell function and may aid in elucidating novel EDC and drug targets contributing to the etiology of male infertility.

Male reproductive function depends on the formation of spermatogonial stem cells from their neonatal precursors, the gonocytes. Previously, we identified several UPS enzymes dynamically altered during gonocyte differentiation. The present work focuses on understanding the role of the RING finger protein 149 (RNF149), an E3 ligase that we found to be strongly expressed in gonocytes and downregulated in spermatogonia. The quantification of RNF149 mRNA from postnatal day (PND) 2 to 35 (puberty) in rat testis, brain, liver, kidney, and heart indicated that its highest levels are found in the testis. RNF149 knock-down in PND3 rat gonocytes was performed to better understand its role in gonocyte development. While a proliferative cocktail of PDGF-BB and 17β-estradiol (P+E) increased both the expression levels of the cell proliferation marker PCNA and RNF149 in mock cells, the effects of P+E on both genes were reduced in cells treated with RNF149 siRNA, suggesting that RNF149 expression is regulated during gonocyte proliferation and that there might be a functional link between RNF149 and PCNA. To examine RNF149 subcellular localization, EGFP-tagged RNF149 vectors were constructed, after determining the rat testis RNF149 mRNA sequence. Surprisingly, two variant transcripts were expressed in rat tissues, predicting truncated proteins, one containing the PA and the other the RING functional domains. Transfection in mouse F9 embryonal carcinoma cells and C18-4 spermatogonial cell lines showed differential subcellular profiles of the two truncated proteins. Overall, the results of this study support a role for RNF149 in gonocyte proliferation and suggest its transcription to variant mRNAs resulting in two proteins with different functional domains. Future studies will examine the respective roles of these variant proteins in the cell lines and isolated gonocytes.

Increasing rates of infertility associated with declining sperm counts and quality, as well as increasing rates of testicular cancer are contemporary issues in the United States and abroad. These conditions are part of the Testicular Dysgenesis Syndrome, which includes a variety of male reproductive disorders hypothesized to share a common origin based on disrupted testicular development during fetal and neonatal stages of life. Male reproductive development is a highly regulated and complex process that relies on an intricate coordination between germ, Leydig, and Sertoli cells as well as other supporting cell types, to ensure proper spermatogenesis, testicular immune privilege, and endocrine function. The eicosanoid system has been reported to be involved in the regulation of fetal and neonatal germ cell development as well as overall testicular homeostasis. Moreover, non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics with abilities to block eicosanoid synthesis by targeting either or both isoforms of cyclooxygenase enzymes, have been found to adversely affect male reproductive development. This review will explore the current body of knowledge on the involvement of the eicosanoid system in male reproductive development, as well as discuss adverse effects of NSAIDs and analgesic drugs administered perinatally, focusing on toxicities reported in the testis and on major testicular cell types. Rodent and epidemiological studies will be corroborated by findings in invertebrate models for a comprehensive report of the state of the field, and to add to our understanding of the potential long-term effects of NSAID and analgesic drug administration in infants.

Summary: Translocator protein (TSPO, 18 kDa) levels increase in parallel with the evolution of simple steatosis (SS) to nonalcoholic steatohepatitis (NASH) in nonalcoholic fatty liver disease (NAFLD). However, TSPO function in SS and NASH is unknown. Loss of TSPO in hepatocytes in vitro downregulated acetyl-CoA acetyltransferase 2 and increased free cholesterol (FC). FC accumulation induced endoplasmic reticulum stress via IRE1A and protein kinase RNA-like ER kinase/ATF4/CCAAT-enhancer-binding protein homologous protein pathways and autophagy. TSPO deficiency activated cellular adaptive antioxidant protection; this adaptation was lost upon excessive FC accumulation. A TSPO ligand 19-Atriol blocked cholesterol binding and recapitulated many of the alterations seen in TSPO-deficient cells. These data suggest that TSPO deficiency accelerated the progression of SS. In NASH, however, loss of TSPO ameliorated liver fibrosis through downregulation of bile acid synthesis by reducing CYP7A1 and CYP27A1 levels and increasing farnesoid X receptor expression. These studies indicate a dynamic and complex role for TSPO in the evolution of NAFLD.

Abstract Di(2-ethylhexyl) phthalate (DEHP) and other phthalates are ubiquitous environmental contaminants with endocrine disrupting properties. Two novel plasticizers, 1,4 butanediol dibenzoate (BDB) and dioctyl succinate (DOS), have been proposed as potential replacements. Both have desirable properties as plasticizers and minimal in vitro biological effects. Herein, we present an in utero and lactational exposure study comparing DEHP with BDB, DOS, and 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH), a commercial alternative. Timed-pregnant Sprague-Dawley rats were gavaged with vehicle or one of these chemicals at 30 or 300 mg/kg/day from gestational day 8 until postnatal day (PND) 21. The offspring were examined for effects on developmental and endocrine markers until PND 46. DEHP treatment (300 mg/kg) decreased heart weights in dams and induced a significant decrease in anogenital index and an increase in hemorrhagic testes and multinucleated gonocytes in PND 3 male pups. An increase in the incidence of hemorrhagic testes was also observed on PND 8 after exposure to DINCH (30 and 300 mg/kg). The only other effects observed were decreases in serum alanine transaminase and magnesium in BDB 30 exposed dams. These data suggest that both BDB and DOS are viable alternative plasticizers.

Apoptosis is an integral part of the spermatogenic process, necessary to maintain a proper ratio of Sertoli to germ cell numbers and provide an adequate microenvironment to germ cells. Apoptosis may also represent a protective mechanism mediating the elimination of abnormal germ cells. Extensive apoptosis occurs between the first and second postnatal weeks, at the point when gonocytes, precursors of spermatogonial stem cells, should have migrated toward the basement membrane of the tubules and differentiated into spermatogonia. The mechanisms regulating this process are not well-understood. Gonocytes undergo phases of proliferation, migration, and differentiation which occur in a timely and closely regulated manner. Gonocytes failing to migrate and differentiate properly undergo apoptosis. Inadequate gonocyte differentiation has been suggested to lead to testicular germ cell tumor (TGCT) formation. Here, we examined the expression levels of apoptosis-related genes during gonocyte differentiation by quantitative real-time polymerase chain reaction, identifying 48 pro- and anti-apoptotic genes increased by at least two-fold in rat gonocytes induced to differentiate by retinoic acid, when compared to untreated gonocytes. Further analysis of the most highly expressed genes identified the pro-apoptotic genes Gadd45a and Cycs as upregulated in differentiating gonocytes and in spermatogonia compared with gonocytes. These genes were also significantly downregulated in seminomas, the most common type of TGCT, compared with normal human testicular tissues. These results indicate that apoptosis-related genes are actively regulated during gonocyte differentiation. Moreover, the down-regulation of pro-apoptotic genes in seminomas suggests that they could represent new therapeutic targets in the treatment of TGCTs.

Peroxiredoxins (PRDXs) are antioxidant enzymes that protect cells from oxidative stress and play a role in reactive oxygen species (ROS)-mediated signaling. We reported that PRDXs are critical for human fertility by maintaining sperm viability and regulating ROS levels during capacitation. Moreover, studies on Prdx6−/− mice revealed the essential role of PRDX6 in the viability, motility, and fertility competence of spermatozoa. Although PRDXs are abundant in the testis and spermatozoa, their potential role at different phases of spermatogenesis and in perinatal germ cells is unknown. Here, we examined the expression and role of PRDXs in isolated rat neonatal gonocytes, the precursors of spermatogonia, including spermatogonial stem cells. Gene array, qPCR analyses showed that PRDX1, 2, 3, 5, and 6 transcripts are among the most abundant antioxidant genes in postnatal day (PND) 3 gonocytes, while immunofluorescence confirmed the expression of PRDX1, 2, and 6 proteins. The role of PRDXs in gonocyte viability was examined using PRDX inhibitors, revealing that the 2-Cys PRDXs and PRDX6 peroxidases activities are critical for gonocytes viability in basal condition, likely preventing an excessive accumulation of endogenous ROS in the cells. In contrast to its crucial role in spermatozoa, PRDX6 independent phospholipase A2 (iPLA2) activity was not critical in gonocytes in basal conditions. However, under conditions of H2O2-induced oxidative stress, all these enzymatic activities were critical to maintain gonocyte viability. The inhibition of PRDXs promoted a two-fold increase in lipid peroxidation and prevented gonocyte differentiation. These results suggest that ROS are produced in neonatal gonocytes, where they are maintained by PRDXs at levels that are non-toxic and permissive for cell differentiation. These findings show that PRDXs play a major role in the antioxidant machinery of gonocytes, to maintain cell viability and allow for differentiation.