FSH inhibits autophagy and lysosomal biogenesis to regulate protein degradation in cultured goat Sertoli cells

ROS-DRP1-mediated excessive mitochondrial fission and autophagic flux inhibition contribute to heat stress-induced apoptosis in goat Sertoli cells

BACKGROUND

Heat stress (HS) poses a significant threat to male goat reproduction. Sertoli cells (SCs) provide both structural and nutritional support necessary for germ cells. HS induces physiological and biochemical changes in SCs. Nevertheless, the molecular mechanisms involved are still not fully understood. Melatonin is a classic antioxidant that can alleviate HS-induced male reproductive damage. However, the underlying molecular mechanisms by which melatonin mitigates damage to goat testicular SCs remain unclear and require further investigation.

RESULTS

In this study, an in vivo heat stress model was established in goats. The results showed that HS exposure led to testicular injury, abnormal spermatogenesis and apoptosis of SCs. To elucidate the mechanism of HS-induced SC apoptosis, primary SCs were isolated and cultured from goat testes, then exposed to HS. HS exposure increased the production of reactive oxygen species (ROS), decreased adenosine triphosphate (ATP) synthesis, and reduced mitochondrial membrane potential in SCs. Additionally, HS increased the expression of mitochondrial fission proteins 1 (FIS1) and dynamin-related protein 1 (DRP1) while decreasing the expression of mitochondrial fusion proteins Mitofusin 1 (MFN1), Mitofusin 2 (MFN2), and optic atrophy 1 (OPA1). This resulted in excessive mitochondrial fission and mitochondria-dependent apoptosis. Mdivi-1 (DRP1 inhibitor) reduces mitochondria-dependent apoptosis by inhibiting excessive mitochondrial fission. Mitochondrial fission is closely related to mitophagy. HS activated upstream mitophagy but inhibited autophagic flux, disrupting mitophagy and exacerbating mitochondria-dependent apoptosis. Finally, the classical antioxidant melatonin was shown to reduce mitochondria-dependent apoptosis in SCs exposed to HS by decreasing ROS levels, restoring mitochondrial homeostasis, and normalizing mitophagy.

CONCLUSIONS

In summary, these findings indicated that the mechanism of HS-induced mitochondria-dependent apoptosis in SCs is mediated by hyperactivation of the ROS-DRP1-mitochondrial fission axis and inhibition of mitochondrial autophagy. Melatonin inhibited HS-induced mitochondria-dependent apoptosis in SCs by restoring mitochondrial homeostasis. This study enhances the understanding of the mechanisms through which heat stress triggers apoptosis and provides a vision for the development of drugs against HS by targeting mitochondria in goats.

Roles of thyroid and leptin hormones and their crosstalk in male reproductive functions: an updated review

PURPOSE

This review aims to provide updated information regarding the role of thyroid and leptin hormones and their crosstalk in affecting the male reproductive function in hypothyroid and obesity conditions.

METHOD

A wide literature search was made using online search engines on published articles using keywords including thyroid hormone, hypothyroidism, leptin hormone, hyperleptinemia, obesity, the relationship between thyroid and leptin hormones and male reproduction, and hypothyroidism, obesity, and male reproduction.

RESULTS

All information pertaining thyroid and leptin hormone effects on male reproduction, hypothyroidism, hyperleptinemia, and obesity effect on male fertility as well as the related molecular mechanisms are obtained.

CONCLUSION

Thyroid and leptin hormones individually play a significant role in male reproduction. Alterations of these hormones' levels could adversely affect the male reproductive functions. PI3K/AKT signaling was found to be the major signaling pathway involved in mediating the effect of both hormones on male reproduction. Impaired crosstalk between the two hormones may occur in hypothyroidism with obesity which would contribute towards male reproductive dysfunction.

HBx-induced upregulation of MAP1S drives hepatocellular carcinoma proliferation and migration via MAP1S/Smad/TGF-β1 loop

Hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC), has a significantly higher risk of recurrence. However, the exact mechanism by which HBV prompts HCC recurrence remains largely unknown. In this study liver microarray test revealed significant upregulation of microtubule associated protein 1S (MAP1S) in metastatic HCC compared to control. MAP1S knockdown suppressed growth of HCCLM3 cells in vitro and in vivo. Mechanistically, HBV-encoded X protein (HBx) upregulates MAP1S, which enhances microtubule (MT) acetylation by promoting the degradation of histone deacetylase 6 (HDAC6), and facilitates the nuclear translocation of Smad complex, and thereby enhancing downstream TGF-β signaling. Smad complex, in turn, increases MAP1S, establishing a feedback loop of MAP1S/Smad/TGF-β1. Finally, survival analysis of 150 HBV-associated HCC patients demonstrated both increased MAP1S and decreased HDAC6 were significantly associated with shorter relapse-free survival. Collectively, this study reveals a unique mechanism whereby HBx-induced upregulation of MAP1S drives HBV-related HCC proliferation and migration through the MAP1S/Smad/TGF-β1 feedback loop. TEASER: MAP1S is a key link between HBV infection and a higher risk of metastatic recurrence of HCC.

Research progress on the role of autophagy in the development of varicocele

Varicocele (VC) is a common cause of infertility in men. Pathophysiological changes caused by VC, such as testicular hypoxia, high temperatures, oxidative stress, abnormal reproductive hormones, and Cd accumulation, can induce autophagy, thus affecting the reproductive function in patients with this condition. Autophagy regulators can be classified as activators or inhibitors. Autophagy activators upregulate autophagy, reduce the damage to the testis and epididymis, inhibit spermatogenic cell apoptosis, and protect fertility. In contrast, autophagy inhibitors block autophagy and aggravate the damage to the reproductive functions. Therefore, elucidating the role of autophagy in the occurrence, development, and regulation of VC may provide additional therapeutic options for men with infertility and VC. In this review, we briefly describe the progress made in autophagy research in the context of VC.

Unveiling the roles of Sertoli cells lineage differentiation in reproductive development and disorders: a review

In mammals, gonadal somatic cell lineage differentiation determines the development of the bipotential gonad into either the ovary or testis. Sertoli cells, the only somatic cells in the spermatogenic tubules, support spermatogenesis during gonadal development. During embryonic Sertoli cell lineage differentiation, relevant genes, including WT1, GATA4, SRY, SOX9, AMH, PTGDS, SF1, and DMRT1, are expressed at specific times and in specific locations to ensure the correct differentiation of the embryo toward the male phenotype. The dysregulated development of Sertoli cells leads to gonadal malformations and male fertility disorders. Nevertheless, the molecular pathways underlying the embryonic origin of Sertoli cells remain elusive. By reviewing recent advances in research on embryonic Sertoli cell genesis and its key regulators, this review provides novel insights into sex determination in male mammals as well as the molecular mechanisms underlying the genealogical differentiation of Sertoli cells in the male reproductive ridge.

ATP10A deficiency results in male-specific infertility in mice

Over 8% of couples worldwide are affected by infertility and nearly half of these cases are due to male-specific issues where the underlying cause is often unknown. Therefore, discovery of new genetic factors contributing to male-specific infertility in model organisms can enhance our understanding of the etiology of this disorder. Here we show that murine ATP10A, a phospholipid flippase, is highly expressed in male reproductive organs, specifically the testes and vas deferens. Therefore, we tested the influence of ATP10A on reproduction by examining fertility of Atp10A knockout mice. Our findings reveal that Atp10A deficiency leads to male-specific infertility, but does not perturb fertility in the females. The Atp10A deficient male mice exhibit smaller testes, reduced sperm count (oligozoospermia) and lower sperm motility (asthenozoospermia). Additionally, Atp10A deficient mice display testes and vas deferens histopathological abnormalities, as well as altered total and relative amounts of hormones associated with the hypothalamic-pituitary-gonadal axis. Surprisingly, circulating testosterone is elevated 2-fold in the Atp10A knockout mice while luteinizing hormone, follicle stimulating hormone, and inhibin B levels were not significantly different from WT littermates. The knockout mice also exhibit elevated levels of gonadotropin receptors and alterations to ERK, p38 MAPK, Akt, and cPLA2-dependent signaling in the testes. Atp10A was knocked out in the C57BL/6J background, which also carries an inactivating nonsense mutation in the closely related lipid flippase, Atp10D. We have corrected the Atp10D nonsense mutation using CRISPR/Cas9 and determined that loss of Atp10A alone is sufficient to cause infertility in male mice. Collectively, these findings highlight the critical role of ATP10A in male fertility in mice and provide valuable insights into the underlying molecular mechanisms.

Fluorochloridone induces mitochondrial dysfunction and apoptosis in primary goat Sertoli cells

Fluorochloridone (FLC), a pyrrolidone herbicide, has been recognized as a hazardous chemical. The in vitro adverse effects of FLC on the reproduction of livestock have not been assessed. This study was conducted to explore the cytotoxicity and toxicological mechanisms of FLC on cultured goat Sertoli cells. The results showed that FLC exposure significantly decreased goat Sertoli cell viability (p < 0.05) and induced oxidative stress. And FLC treatment promoted apoptosis and initiation of autophagy. Interestingly, FLC inhibited lysosomal biogenesis and blocked autophagic flux in goat Sertoli cells. The expression levels of autophagy-related proteins Atg5, LC3II, and p62 were significantly increased (p < 0.05) in FLC-treated goat Sertoli cells compared with the control. Importantly, FLC-induced ROS accumulation further causes mitochondrial dysfunction and disturbs mitophagy. FLC significantly decreased (p < 0.05) the expression levels of OPA1, MFN2, p-Drp1, FIS1, PINK1, and Parkin in goat Sertoli cells. Moreover, pretreatment with N-acetyl-l-cysteine (NAC, an antioxidant) significantly reduced (p < 0.01) FLC-induced ROS accumulation and reversed the disorder of autophagy levels. Our results indicated that FLC-induced toxicity in primary goat Sertoli cells was characterized by ROS accumulation, inducing oxidative stress, inhibiting lysosomal biogenesis, blocking autophagic flux, and promoting mitochondrial dysfunction, resulting in apoptosis via the mitochondrial pathway.

Zearalenone Induces Blood-Testis Barrier Damage through Endoplasmic Reticulum Stress-Mediated Paraptosis of Sertoli Cells in Goats

Zearalenone (ZEA) is present worldwide as a serious contaminant of food and feed and causes male reproductive toxicity. The implication of paraptosis, which is a nonclassical paradigm of cell death, is unclear in ZEA-induced male reproductive disorders. In this study, the toxic effects of ZEA on the blood-testis barrier (BTB) and the related mechanisms of paraptosis were detected in goats. ZEA exposure, in vivo, caused a significant decrease in spermatozoon quality, the destruction of seminiferous tubules, and damage to the BTB integrity. Furthermore, ZEA exposure to Sertoli cells (SCs) in vitro showed similar dysfunction in structure and barrier function. Importantly, the formation of massive cytoplasmic vacuoles in ZEA-treated SCs corresponded to the highly swollen and dilative endoplasmic reticulum (ER), and paraptosis inhibition significantly alleviated ZEA-induced SC death and vacuolization, which indicated the important contribution of paraptosis in ZEA-induced BTB damage. Meanwhile, the expression of ER stress marker proteins was increased after ZEA treatment but decreased under the inhibition of paraptosis. The vacuole formation and SC death, induced by ZEA, were remarkably blocked by ER stress inhibition. In conclusion, these results facilitate the exploration of the mechanisms of the SC paraptosis involved in ZEA-induced BTB damage in goats.

Roles of follicle stimulating hormone and sphingosine 1-phosphate co-administered in the process in mouse ovarian vitrification and transplantation

Some major challenges of ovarian tissue vitrification and transplantation include follicle apoptosis induced by cryopreservation and ischemia-reperfusion injury, as well as ovarian follicle loss during post-transplantation. This research aimed to investigate the protective effects and underlying mechanisms of follicle-stimulating hormone (FSH) and Sphingosine-1-phosphate (S1P) on vitrified and post-transplantation ovaries. Ovaries from 21-day-old mice were cryopreservation by vitrification with 0.3 IU/mL FSH, 2 µM S1P, and 0.3 IU/mL FSH + 2 µM S1P, respectively, for follicle counting and detection of apoptosis-related indicators. The results demonstrated that FSH and S1P co-intervention during the vitrification process could preserve the primordial follicle pool and inhibit follicular atresia by suppressing cell apoptosis. The thawed ovaries were transplanted under the renal capsule of 6-8 week-old ovariectomized mice and removed 24 h or 7 days after transplantation. The results indicated that FSH and S1P co-intervention can inhibit apoptosis and autophagy in ovaries at 24 h after transplantation, and promote follicle survival by up-regulating Cx37 and Cx43 expression, enhanced angiogenesis in transplanted ovaries by promoting VEGF expression, as well as increased the E2 levels to restore ovarian endocrine function at 7 days after transplantation. The hypoxia and ischemia cell model was established by CoCl2 treatment for hypoxia in human granulosa-like tumor cell line (KGN), as well as serum-free culture system was used for ischemia. The results confirmed that ischemia-hypoxia-induced apoptosis in ovarian granulosa cells was reduced by FSH and S1P co-intervention, and granulosa cell autophagy was inhibited by up-regulating the AKT/mTOR signaling pathway. In summary, co-administration of FSH and S1P can maintain ovarian survival during ovarian vitrification and increase follicle survival and angiogenesis after transplantation.

Enhanced autophagy reversed aflatoxin B1-induced decrease in lactate secretion of dairy goat Sertoli cells

The deleterious effects of aflatoxins, especially aflatoxin B1 (AFB1) which are widespread at all stages of food production, on the reproductive system have been widely reported in males. However, it is still far from fully understood about the toxic effect and molecular mechanism after exposure to AFB1 in various testicular cells, especially Sertoli cells (SCs) which provide various energy materials and support to the developing germ cells as nurse cells. In this work, we examined the effects of AFB1 in dairy goat SCs on lactate production and autophagy, and the role of autophagy on AFB1-induced reduction in lactate production. Mechanistically, AFB1 destroyed the energy balance and reduced the secretion of lactate in dairy goat SCs (P < 0.01), resulting in a reduced level of ATP (P < 0.01) and phosphorylation of AMPK (P < 0.01). Subsequently, activated AMPK triggers autophagy by directly phosphorylating ULK1 (P < 0.05). The enhancement of autophagy partially reversed the AFB1-induced decrease in lactate secretion by promoting glucose utilization (P < 0.01) and increasing the expression of proteins related to lactate secretion in dairy goat SCs (P < 0.05) such as GLUT1, GLUT3, LDHA, and MCT4. Collectively, our study suggests that AFB1 inhibits the secretion of lactate which supply for germ cell development by damaging the "Warburg-like" metabolism of dairy goat SCs. Moreover, autophagy contributes to the resistance of glucose metabolism damage induced by AFB1. DATA AVAILABILITY: All data generated or analyzed in this study are available from the corresponding authors upon request.

Artemisia annua L. (Sweet wormwood) leaf extract attenuates high-fat diet-induced testicular dysfunctions and improves spermatogenesis in obese rats

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia annua L., known as "sweet wormwood," is widely used in Egyptian folk medicine. Egyptians implement the aerial parts in the treatment of respiratory, digestive and sexual dysfunctions. However, the mechanism by which Artemisia annua improves testicular function is still being discovered.

AIM OF THE STUDY

This study aimed to evaluate the modulatory effects of the crude leaf extract of Artemisia annua (AAE) on a high-fat diet induced testicular dysfunction in rats and compare it with the antilipolytic drug Orlistat.

MATERIAL AND METHODS

Forty adult rats were randomly classified and assigned to four groups. The first group typically consumed a balanced diet and served as a negative control (GP1). A high-fat diet-induced obesity was applied to the other three groups for 12 weeks. A positive control remained on HFD for another 8 weeks, which is GP2. Other groups were administered for 8 consecutive weeks either with Orlistat (50 mg/kg body weight) or AAE (100 mg/kg body weight), which have been defined as GP3 and GP4, respectively. Testosterone (TST), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were determined in the sera of all groups. In addition, the oxidant/antioxidant biomarkers such as protein carbonyl, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) activities, lactate dehydrogenase (LDH) and creatine kinase isoenzyme-B (CK-MB) were determined. An immunohistochemical stain with the apoptotic marker caspase-3 and the proliferating cell nuclear antigen (PCNA) were also investigated.

RESULTS

In the testes of the obese group, the results showed hormonal imbalance, an increase in oxidative stress biomarkers and apoptosis. In the group treated with orlistat (GP3), noticeably more perturbations were noted. The obese rats that had been treated with AAE (GP4) showed a significantly reduced level of oxidative stress, hormonal balance restoration and reduced apoptosis.

CONCLUSIONS

The crude leaf extract of A. annua is a potential herbal therapeutic for the treatment of obesity-related testicular dysfunction and the restoration of hormonal imbalance in obese rats.

Zearalenone induces oxidative stress and autophagy in goat Sertoli cells

Zearalenone (ZEA), one of the non-steroidal estrogen mycotoxin, can cause male reproductive damage and genotoxicity in mammals. Testicular oxidative injury is an important factor causing male sterility. Testicular Sertoli cells are essential for spermatogenesis and male fertility. At present, the mechanism of oxidative injury in dairy goat Sertoli cells after exposure to ZEA remains unclear. This study explored the effects of ZEA on oxidative stress and autophagy in dairy goat Sertoli cells. It was found that treatment of primary Sertoli cells with 25, 50 and 100 μmol/L ZEA for 24 h can promote ROS production, decrease cell viability, antioxidant enzyme activity and mitochondrial membrane potential, induce caspase-dependent cell apoptosis and autophagy activity. ZEA-induced autophagy was confirmed by LC3-I/LC3-II transformation. More importantly, N-acetylcysteine (NAC) pretreatment can remarkably inhibit ZEA-induced oxidative stress, apoptosis and autophagy in Sertoli cells by eliminating ROS. In conclusion, this study indicates that ZEA induces oxidative stress and autophagy in dairy goat Sertoli cells by promoting ROS production.

Effects of N-Acetylcysteine on the Proliferation, Hormone Secretion Level, and Gene Expression Profiles of Goat Ovarian Granulosa Cells

The purpose of this paper was to investigate the effects of N-acetylcysteine (NAC) on the proliferation, hormone secretion, and mRNA expression profiles of ovarian granulosa cells (GCs) in vitro. A total of 12 ovaries from 6 follicular-stage goats were collected for granulosa cell extraction. The optimum concentration of NAC addition was determined to be 200 μM via the Cell Counting Kit 8 (CCK-8) method. Next, GCs were cultured in a medium supplemented with 200 μM NAC (200 μM NAC group) and 0 μ M NAC (control group) for 48 h. The effects of 200 μM NAC on the proliferation of granulosa cells and hormones were studied by 5-ethynyl-2'-deoxyuridine (EdU) assay and enzyme-linked immunosorbent assay (ELISA). mRNA expression was analyzed by transcriptome sequencing. The results indicate that 200 μM NAC significantly increased cell viability and the proportion of cells in the S phase but promoted hormone secretion to a lesser degree. Overall, 122 differentially expressed genes (DEGs) were identified. A total of 51 upregulated and 71 downregulated genes were included. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that the most DEGs were enriched in terms of cell growth regulation, cell growth, neuroactive ligand-receptor interaction, cytokine-cytokine receptor interaction, the cAMP-signaling pathway, and the Wnt-signaling pathway. Seven genes related to granulosa cell proliferation were screened, IGFBP4, HTRA4, SST, SSTR1, WISP1, DAAM2, and RSPO2. The above results provide molecular theoretical support for NAC as a feed additive to improve follicle development and improve reproductive performance in ewes.

Follicle-stimulating hormone signaling in Sertoli cells: a licence to the early stages of spermatogenesis

Follicle-stimulating hormone signaling is essential for the initiation and early stages of spermatogenesis. Follicle-stimulating hormone receptor is exclusively expressed in Sertoli cells. As the only type of somatic cell in the seminiferous tubule, Sertoli cells regulate spermatogenesis not only by controlling their own number and function but also through paracrine actions to nourish germ cells surrounded by Sertoli cells. After follicle-stimulating hormone binds to its receptor and activates the follicle-stimulating hormone signaling pathway, follicle-stimulating hormone signaling will establish a normal Sertoli cell number and promote their differentiation. Spermatogonia pool maintenance, spermatogonia differentiation and their entry into meiosis are also positively regulated by follicle-stimulating hormone signaling. In addition, follicle-stimulating hormone signaling regulates germ cell survival and limits their apoptosis. Our review summarizes the aforementioned functions of follicle-stimulating hormone signaling in Sertoli cells. We also describe the clinical potential of follicle-stimulating hormone treatment in male patients with infertility. Furthermore, our review may be helpful for developing better therapies for treating patients with dysfunctional follicle-stimulating hormone signaling in Sertoli cells.