Autophagy modulation in resveratrol protective effects on steroidogenesis in high-fat diet-fed mice and H2O2-challenged TM3 cells.

BACKGROUND: Autophagy dysregulation and oxidative stress play critical pathophysiological roles in developing obesity-related metabolic health disorders. This study aims to investigate how autophagy modulation is related to resveratrol (RSV) antioxidant activities and preventive effects on steroidogenesis decline associated with a high-fat diet (HFD) and oxidative damage. METHODS AND RESULTS: Eight-week-old C57BL/6 J male mice were fed with HFD with or without supplement RSV (400 mg/kg/day) by gavage for 16 weeks. The control group was fed with a standard diet with no RSV or the same amount of RSV. Mouse Leydig cell line TM3 cell was used for in vitro studies. Oxidative stress was induced in TM3 cells with H2O2, followed by RSV treatment plus autophagy activator rapamycin or autophagy inhibitor 3-methyladenine, respectively. RSV supplement could upregulate proteins level of StAR and mitochondrial proteins COX4 and mtTFA, indicating the amelioration of steroidogenesis decline and mitochondrial dysfunction caused by HFD. Antioxidants such as GPx4 and SOD2 were improved by RSV as well. The observation of autophagosomes and the changes in expressions of LC3II/I, Beclin1, and Atg7 indicated that RSV could reverse the autophagy defect associated with HFD. 3-methyladenine inhibition of autophagy partially abolished RSV protection on mitochondrial function and steroidogenesis in H2O2-challenged TM3 cells. However, the combination use of rapamycin and RSV did not improve protection on Leydig cells against oxidative damage. CONCLUSIONS: The stimulation of autophagy by RSV is closely linked to its antioxidant actions and positive impact on steroidogenesis in HFD mice. The findings suggest RSV is protective against obesity-related Leydig cell impairment.

Impact of diabetic hyperglycaemia and insulin therapy on autophagy and impairment in rat epididymis.

Blood glucose dysregulation and hyperglycaemia caused by diabetes mellitus are intimately associated with male infertility. Two-month-old Sprague-Dawley rats were given a single dose of streptozotocin (55 mg/kg) by intraperitoneal injection to induce type I diabetes mellitus (DM group). The treatment group was given 1 unit/day of insulin for 16 weeks (INS group). The normal control group (NC group) was given food ad libitum. In the DM group, the histological analysis of caput and cauda epididymal ducts showed broken stereocilia and more lipid vacuolisations in the principal cells. The interstitial hyperplasia and inflammatory cell infiltration were observed in epididymal tissues. Transmission electron microscopy observation showed that the principal cells in the DM group contained more vacuoles, partly lost stereocilia, and swollen mitochondria. The autophagosomes were observed as well. Western blotting results of LC3II/I and P62 protein expression indicated that autophagy was downregulated in the DM group. The total antioxidant activity and GPx5 expression of epididymal tissues were also decreased. In the INS group, significant improvements were observed in epididymal tissues. Our study suggests that diabetic hyperglycaemia causes autophagy dysregulation in epididymal tissues, which may play a role in diabetes-induced rat epididymal injury. Insulin treatment is beneficial for diabetic-associated epididymal dysfunction.

Comparative proteomics reveals protective effect of resveratrol on a high-fat diet-induced damage to mice testis.

In recent years, resveratrol has been shown to protect against metabolic damage, including obesity-associated subfertility/infertility. In the present study, proteomic alterations in testicular tissues were investigated by tandem mass tag (TMT) in mice fed with a high-fat diet (HFD) without or with resveratrol supplementation (HFD+RSV). Serum testosterone levels, spermatozoa parameters and testicular histological morphology were assessed. Resveratrol treatment was shown to significantly reduce serum cholesterol, prevent the HFD-induced reductions in serum testosterone and spermatozoa parameters, and decrease the ultrastructural degeneration of testicular tissues. The comparative proteomics analysis revealed 58 differentially expressed proteins between the HFD and control groups and 38 differentially expressed proteins between the HFD and HFD+RSV groups. Gene ontology (GO) term enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the most highly enriched differential proteins were correlated to spermatozoa function and cholesterol metabolism. The real-time RT-PCR and western blotting results confirmed the differential expression of the corresponding proteins related to spermatozoa function that were identified by proteomics. The present study provides new insight into the mechanisms of the beneficial effects of resveratrol, and may present it as a potential therapeutic strategy for obesity-associated male subfertility/infertility.Abbreviations:TMT: Tandem mass tag; HFD: High-fat diet; RSV: Resveratrol; GO: Gene ontology; Protein-proteinKEGG: Kyoto Encyclopedia of Genes and Genomes; RT-PCR: Reverse transcription-polymerase chain reaction; SDS-PAGE: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis; PVDF: Polyvinylidene fluoride; ECL: Enhanced chemiluminescence; RIPA: Radio-immunoprecipitation assay; CTRL: Control; PPI: interaction; RIA: Radioimmunoassay; T: Testosterone; TG: Triglycerides; TC: Total cholesterol; LDL-c: Low-density lipoprotein cholesterol; HDL-c: High-density lipoprotein cholesterol; Crisp1: Cysteine-rich secretory protein 1; SIRT1: Sirtuin 1; GPx5: Glutathione peroxidase 5; Svs4: Seminal vesicle secretory protein 4; Tssk3: Testis-specific serine kinase 3; Pate4: Prostate and testis expressed 4; Sva: Seminal vesicle antigen; Lcn5: Lipocalin 5; Spinkl: Serine protease inhibitor, Kazal type-like.

Melatonin appears to protect against steroidogenic collapse in both mice fed with high-fat diet and H2 O2 -treated TM3 cells.

High-fat diets (HFDs) are detrimental to steroidogenesis and male fertility. This study aimed to investigate the protective effects of melatonin (MT) treatment on testicular dysfunction in mice fed with HFD. C57BL/6J male mice were randomly divided into three groups: CTRL, HFD and HFD + MT. MT treatment mitigated the increase in body weight and adipose tissue in HFD-fed mice. Serum levels of sex hormones were improved upon MT supplementation, and the expression of the testosterone synthesis proteins, StAR and P450scc was rescued as well. MT treatment significantly up-regulated the expression of SIRT1, SOD2, and GPx4 and down-regulated the expression of GRP78 and CHOP, indicating an attenuation of oxidative stress (OS) and endoplasmic reticulum (ER) stress. In TM3 cells, MT treatment protected against H2 O2 -induced steroidogenic collapse by improving mitochondrial function and attenuating OS and ER stress. These results indicate that MT treatment can improve steroidogenesis in mice fed with HFD and may have therapeutic value in the treatment of obesity-associated hypogonadism.

Vitamin D3 inhibits lipopolysaccharide-induced placental inflammation through reinforcing interaction between vitamin D receptor and nuclear factor kappa B p65 subunit.

It is increasingly recognized that vitamin D3 (VitD3) has an anti-inflammatory activity. The present study investigated the effects of maternal VitD3 supplementation during pregnancy on LPS-induced placental inflammation and fetal intrauterine growth restriction (IUGR). All pregnant mice except controls were intraperitoneally injected with LPS (100 µg/kg) daily from gestational day (GD)15-17. In VitD3 + LPS group, pregnant mice were orally administered with VitD3 (25 µg/kg) before LPS injection. As expected, maternal LPS exposure caused placental inflammation and fetal IUGR. Interestingly, pretreatment with VitD3 repressed placental inflammation and protected against LPS-induced fetal IUGR. Further analysis showed that pretreatment with VitD3, which activated placental vitamin D receptor (VDR) signaling, specifically suppressed LPS-induced activation of nuclear factor kappa B (NF-κB) and significantly blocked nuclear translocation of NF-κB p65 subunit in trophoblast gaint cells of the labyrinth layer. Conversely, LPS, which activated placental NF-κB signaling, suppressed placental VDR activation and its target gene expression. Moreover, VitD3 reinforced physical interaction between placental VDR and NF-κB p65 subunit. The further study demonstrates that VitD3 inhibits placental NF-κB signaling in VDR-dependent manner. These results provide a mechanistic explanation for VitD3-mediated anti-inflammatory activity. Overall, the present study provides evidence for roles of VDR as a key regulator of placental inflammation.

Resveratrol attenuates inflammation and oxidative stress in epididymal white adipose tissue: implications for its involvement in improving steroidogenesis in diet-induced obese mice.

Chronic, low-grade systemic inflammation has been shown to play an important role in the development of obesity-related complications. Epididymal white adipose tissue (WAT) can influence testicular function through its endocrine function. The purpose of this study was to assess the effects of resveratrol on the epididymal WAT inflammatory response and on testicular steroidogenesis in obese individuals. Seven-week-old male C57BL/6J mice were fed a high-calorie and high-cholesterol diet (HCD group) or HCD supplemented with resveratrol (HCD+Res group) for 18 weeks. As we previously showed that resveratrol protects against Leydig cell steroidogenesis in HCD-induced obese mice, this study assessed macrophage infiltration in fat depots by measuring crown-like structure (CLS) density. Histological analysis showed that adipocyte size was significantly smaller and CLSs were less numerous in the HCD+Res group than the HCD group (P < 0.01). Additionally, resveratrol supplementation decreased Nfkb1 expression (P < 0.01) and increased the IκB-α protein abundance (P < 0.01) in epididymal WAT. Consistent with this alteration in NF-κB signaling, the expression of two classic proinflammatory cytokines, TNF-α (Tnfa) and IL-1ß (Il1b), were significantly decreased in the HCD+Res group compared with the HCD group (P < 0.01). Significant differences were also found in the expression of sirtuin1 (Sirt1) (P < 0.01) and manganese superoxide dismutase (Sod2) (P < 0.01) between the HCD and HCD+Res groups. Our data suggest that resveratrol can attenuate obesity-induced inflammation and oxidative stress in epididymal WAT, which partly accounts for its beneficial effects in testicular steroidogenesis.

Antifertility characteristics of the N-terminal region of mouse equatorial segment protein.

To investigate antifertility characteristics of the equatorial segment protein (ESP) and its potential immunocontraceptive effect, three partially overlapping cDNA fragments P1/P2/P3, together covering the entire mouse ESP, were cloned, expressed, and purified. The roles of P1/P2/P3 in fertility were investigated through in vitro fertilization and mouse mating test. Antibodies against P1/P2 significantly reduced the rates of fertilization in vitro in the zona-intact experiments. Coincubation of zona-free mouse oocytes with capacitated mouse spermatozoa in the presence of antibodies against P1/P2 also inhibited sperm-oolemma binding and fusion, while anti-P3 antibody virtually had no effect on in vitro fertilization at the same concentration. Immunization of female BALB/c mice with N-terminal of mouse ESP (recombinant P1 and P2) resulted in a significant decrease in the fertility rate as well as the litter size. Double immunofluorescence staining showed that mouse ESP protein was localized to the equatorial segment of acrosome of mouse sperm, and was exposed and surface-accessible after acrosome reaction. Mouse ESP was also demonstrated to have complementary binding sites on the mouse egg plasma membrane by indirect immunofluorescence assay. These findings suggest that the N-terminal of mouse ESP could play an important role in fertility and might be a vaccine candidate for contraception.