1,25(OH)2 vitamin D3 signalling on immature rat Sertoli cells: gamma-glutamyl transpeptidase and glucose metabolism

Melatonin enhances the function of porcine immature Sertoli cells by inhibiting the HMGCS1-estradiol pathway

Melatonin (MT), a neurohormone synthesized and secreted primarily by the pineal gland, is of vital function to animal reproduction. However, the effects of gene expression and metabolism exerted by MT on porcine immature Sertoli cells (iSCs) remain unclear. Here, MT treatment (10 nM, 36h) elevated mitochondrial function and reduced oxidative stress, to promote proliferation and inhibit apoptosis of porcine iSCs. Transcriptome profiling identified 39 differentially expressed genes (DEGs) (33 known and 6 novel) (MT vs. Control), mainly involved in the steroid and glutamine metabolic processes, oxidoreductase activity and G protein coupled receptor binding (GO terms), and steroid biogenesis, pyruvate metabolism and AMPK signal pathways, etc (KEGG pathways). RT-qPCR validated 6 DEGs (Phgdh, Scd, Hmgcs1, Cytb, Pck2 and Sqle), with similar expression pattern to RNA-seq. Metabolomics further showed that 14 metabolites were significantly altered. The HMGCS1 protein abundance and the estradiol level were confirmed to be significantly decreased by MT (10 nM, 36h) treatment, and direct inhibition of HMGCS1 could also significantly reduce the estradiol level. However, levels of cholesterol and lactate were unchanged. Collectively, through integrated transcriptomics and metabolomics analysis, MT is demonstrated to inhibit the HMGCS1-estradiol pathway, to enhance the function of porcine iSCs.

Metabolite of esculetin plays an important role in cytotoxic effects induced by chloroquine on porcine immature Sertoli cells

Chloroquine (CQ) is widely used in the therapy against malarial, tumor and recently the COVID-19 pandemic, as a lysosomotropic agent to inhibit the endolysosomal trafficking in the autophagy pathway. We previously reported that CQ (20 μM, 36 h) could reprogram transcriptome, and impair multiple signaling pathways vital to porcine immature Sertoli cells (iSCs). However, whether CQ treatment could affect the metabolomic compositions of porcine iSCs remains unclear. Here, we showed that CQ (20 μM, 36 h) treatment of porcine iSCs induced significant changes of 63 metabolites (11 up and 52 down) by the metabolomics method, which were involved in different metabolic pathways. Caffeic acid and esculetin, the top two up-regulated metabolites, were validated by ELISA. The combined analysis of metabolomics and transcriptome showed caffeic acid and esculetin to be highly correlated with multiple differentially expressed genes (DEGs), including Ndrg1, S100a8, Sqstm1, S100a12, S100a9, Ill1, Lif, Ntn4 and Peg10. Furthermore, esculetin treatment (53 nM, 36 h) significantly decreased the viability and proliferation, suppressed the mitochondrial function, whereas promoted the apoptosis of porcine iSCs, similar to those by CQ treatment (20 μM, 36 h). Collectively, our results showed that CQ treatment induces metabolic changes, and its effect on porcine iSCs could be partially mediated by esculetin.

Melatonin mitigates Chloroquine-induced defects in porcine immature Sertoli cells

Chloroquine (CQ) could function as a lysosomotropic agent to inhibit the endolysosomal trafficking in the autophagy pathway, and is widely used on malarial, tumor and recently COVID-19. However, the effect of CQ treatment on porcine immature Sertoli cells (iSCs) remains unclear. Here we showed that CQ could reduce iSC viability in a dose-dependent manner. CQ treatment (20 μM) on iSCs for 36h could elevate oxidative stress, damage mitochondrial function and promote apoptosis, which could be partially rescued by melatonin (MT) (10 nM). Transcriptome profiling identified 1611 differentially expressed genes (DEGs) (776 up- and 835 down-regulated) (20 μM CQ vs. DMSO), mainly involved in MAPK cascade, cell proliferation/apoptosis, HIF-1, PI3K-Akt and lysosome signaling pathways. In contrast, only 467 (224 up- and 243 down-regulated) DEGs (CQ + MT vs. DMSO) could be found after MT (10 nM) addition, enriched in cell cycle, regulation of apoptotic process, lysosome and reproduction pathways. Therefore, the partial rescue effects of MT on CQ treatment were confirmed by multiple assays (cell viability, ROS level, mitochondrial function, apoptosis, and mRNA levels of selected genes). Collectively, CQ treatment could impair porcine iSC viability by deranging the signaling pathways related to apoptosis and autophagy, which could be partially rescued by MT supplementation.

Estradiol and 1α,25(OH)2 vitamin D3 share plasma membrane downstream signal transduction through calcium influx and genomic activation in immature rat testis

The aim of this study was to investigate the rapid response pathway and gene and protein expression profiles of the rat testis in response to estradiol (E₂) and 1α,25(OH)₂ vitamin D₃ (1,25-D₃), to understand how they mediate their effects on the first spermatogenic wave. To do this, we compared the effects of 1,25-D₃ and E₂ on ⁴⁵calcium(Ca²⁺) uptake and the involvement of estrogen receptors (ESR) in their rapid responses. Additionally, we studied the downstream signal transduction effects of 1,25-D₃ and E₂ on cyclin A1/B1 and cellular cycle protein expression. As previously observed for 1,25-D₃, E₂ also increased ⁴⁵Ca²⁺ uptake in immature rat testes via voltage-dependent Ca²⁺ channels, Ca²⁺-dependent chloride channels and via the activation of protein kinase C, protein kinase A and mitogen-activated protein kinase kinase (MEK). Elevated aromatase expression by testes was observed in the presence of 1,25-D₃ and both hormones decreased ESR mRNA expression. Furthermore, 1,25-D₃ and E₂ diminished cyclin A1 mRNA expression, but E₂ did not affect cyclin B1 mRNA levels. Consistent with these findings, the immunocontent of cyclin A1 and B1 in the testes was also increased by 1,25-D₃ and E₂. 1,25-D₃ increased expressions of the p16 and p53 proteins, supporting the anti-proliferative and pro-apoptotic properties of 1,25-D_3, while E₂ also augmented p16. Data indicate that both hormones trigger rapid responses at the plasma membrane that may control the expression of gene and proteins related to cell cycle regulation, and thereby modulate spermatogenesis.

Common markers of testicular Sertoli cells

INTRODUCTION

Sertoli cells play central roles in the development of testis formation in fetuses and the initiation and maintenance of spermatogenesis in puberty and adulthood, and disorders of Sertoli cell proliferation and/or functional maturation can cause male reproductive disorders at various life stages. It's well documented that various genes are either overexpressed or absent in Sertoli cells during the conversion of an immature, proliferating Sertoli cell to a mature, non-proliferating Sertoli cell, which are considered as Sertoli cell stage-specific markers. Thus, it is paramount to choose an appropriate Sertoli cell marker that will be used not only to identify the developmental, proliferative, and maturation of Sertoli cell status in the testis during the fetal period, prepuberty, puberty, or in the adult, but also to diagnose the mechanisms underlying spermatogenic dysfunction.

AREAS COVERED

In this review, we principally enumerated 5 categories of testicular Sertoli cell markers - including immature Sertoli cell markers, mature Sertoli cell markers, immature/mature Sertoli cell markers, Sertoli cell functional markers, and others.

EXPERT OPINION

By delineating the characteristics and applications of more than 20 Sertoli cell markers, this review provided novel Sertoli cell markers for the more accurate diagnosis and mechanistic evaluation of male reproductive disorders.

Ascorbic acid promotes the reproductive function of porcine immature Sertoli cells through transcriptome reprogramming

Vitamin C (ascorbic acid, AA) can regulate antioxidation and affect many cellular processes. However, the effect of AA on the reproduction of male animals remains less explored. Here, we showed that by supplementing exogenous AA to porcine immature Sertoli cells (iSCs), AA could promote the proliferation, suppress apoptosis, and decrease the global nucleic acid methylation (5 mC and m⁶A) levels of iSCs. After we profiled mRNA and long non-coding RNA (lncRNA) expression by transcriptome sequencing on iSCs (treated by 250 μM AA for 36 h), 1232 mRNAs and 937 lncRNAs were identified to be differentially expressed (DE). Gene enrichment analysis found multiple significantly enriched biological pathways, including oxidoreductase activity, cell proliferation and apoptosis, regulation of hormone level, regulation of catalytic activity, developmental process, ATP metabolism and reproductive process. Specifically, for the reproductive process, 49 up- and 36 down-regulated DE mRNAs (including highly expressed genes, such as Tfcp2l1, Hmgcs1, Mmp7, Fndc3a, and Zfp36l1) are involved. Moreover, AA supplementation could promote the secretion of anti-müllerian hormone, inhibin B and lactate, and enhance the activity of lactate dehydrogenase as well. Taken together, AA could promote the reproductive function of pig iSCs, potentially through reprogramming the global transcriptome, and elevating hormone secretion and metabolite production.

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AA could promote the proliferation, suppress apoptosis, and decrease the global nucleic acid mthylation levels of iSCs.

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AA treatment changed mRNA and lncRNA profiles of iSCs.

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AA treatment significantly disturbed the expression of mRNAs (such as Tfcp2l1, Hmgcs1, Mmp7, Fndc3a, and Zfp36l1) involved in reproductive process.

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AA supplement could promote the secretion of anti-mullerian hormone, inhibin B and lactate, and the activity of lactate dehydrogenase as well.

A Brazilian pulp and paper mill effluent disrupts energy metabolism in immature rat testis and alters Sertoli cell secretion and mitochondrial activity

Our objective was to investigate whether the pulp and paper mill industry effluent could affect the testis and Sertoli cells in a fast exposure period. For this, the present study was carried out in immature rats at 10-day-old. Testis treated in vitro with 4% effluent for 1 h presented changes in energy metabolism in terms of a decrease in lactate content and glucose uptake. Elevation in GSH content, as an antioxidant defense mechanism, was also detected. Sertoli cells treated with 4% effluent for 1 hour showed alterations in the mitochondrial metabolism that favor the decoupling of oxidative phosphorylation and the generation of oxygen reactive species and also a time and concentration-dependent delay secretion of acidic vesicles. Our results showed that pollutants present in the pulp and paper mill effluents, in a short time of exposure, are capable of inducing alterations in important metabolic functions in the testis and in Sertoli cells that are crucial for the correct progression of spermatogenesis and fertility.

Impact of vitamin D deficiency on mouse sperm structure and function

BACKGROUND

In rodents and humans, vitamin D deficiency (VDD) is associated with altered sperm structure and function (primarily decreased motility and morphological abnormalities) that are primarily attributed to VDD-induced hypocalcemia. However, it is suspected that VDD has much more drastic effects on mammalian spermatozoa.

OBJECTIVES

The purpose of this study was to illustrate that VDD, depending on its severity and duration, can alter sperm nuclear integrity and can also lead to the loss of spermatozoa's ability to support embryonic development.

MATERIALS AND METHODS

A mouse model of induced VDD combining the action of a vitamin D-deficient diet, UV exposure limitation, and paricalcitol injections; a vitamin D2 analog that catabolizes endogenous vitamin D by increasing the expression of CYP24A, a member of the cytochrome P450 family, has been used to create different grades of VDD.

RESULTS

We show that the most significant sperm defect recorded concerns the integrity of the paternal nucleus, which is both decondensed and fragmented in moderate-to-severe VDD situations. Consistent with the known consequences of fertilization with DNA-damaged spermatozoa, we show that paternal VDD decreases the ability of spermatozoa to optimally support fertilization and embryonic development.

DISCUSSION AND CONCLUSION

Given the worldwide high prevalence of VDD in humans, and although obtained in an animal model, the data presented here suggest that subfertile/infertile males may benefit from VDD testing and that attempts to correct serum vitamin D levels could be considered prior to conception, either naturally or through ART.

Acute exposure to bis(2-ethylhexyl)phthalate disrupts calcium homeostasis, energy metabolism and induces oxidative stress in the testis of Danio rerio

Bis(2-ethylhexyl)phthalate (BEHP) negatively affects testicular functions in different animal species, disturbing reproductive physiology and male fertility. The present study investigated the in vitro acute effect of BEHP on the mechanism of action of ionic calcium (Ca²⁺) homeostasis and energy metabolism. In addition, the effect of BEHP on oxidative stress was studied in vitro and in vivo in the testis of Danio rerio (D. rerio). Testes were treated in vitro for 30 min with 1 μM BEHP for ⁴⁵Ca²⁺ influx measurements. Testes were also incubated with 1 μM BEHP for 1 h (in vitro) or 12 h (in vivo) for the measurements of lactate content, ¹⁴C-deoxy-d-glucose uptake, lactate dehydrogenase (LDH) and gamma-glutamyl transpeptidase (GGT) activity, total reactive oxygen species (ROS) production and lipid peroxidation. In addition, the effect of BEHP (1 μM) on GGT, glutamic oxaloacetic transferase (GOT) and glutamic pyruvic transferase (GPT) activity in the liver was evaluated after in vivo treatment for 12 h. BEHP disturbs the Ca²⁺ balance in the testis when given acutely in vitro. BEHP stimulated Ca²⁺ influx occurs through L-type voltage-dependent Ca²⁺ channels (L-VDCC), transitory receptor potential vaniloid (TRPV1) channels, reverse-mode Na⁺/Ca²⁺ exchanger (NCX) activation and inhibition of sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA). BEHP affected energy metabolism in the testis by decreasing the lactate content and LDH activity. In vitro and in vivo acute effects of BEHP promoted oxidative stress by increasing ROS production, lipid peroxidation and GGT activity in the testis. Additionally, BEHP caused liver damage by increasing GPT activity.