4-Nonylphenol induces apoptosis, autophagy and necrosis in Sertoli cells: Involvement of ROS-mediated AMPK/AKT-mTOR and JNK pathways

Assessing testicular morphofunctionality under Roundup WG® herbicide exposure in zebrafish

Glyphosate-based herbicides, like Roundup WG® (RWG) used for a range of crops, such as corn, soybean, coffee, sugarcane, rice, apple, and citrus, can reach aquatic ecosystems and impact non-target organisms like fish. Thus, the fish were exposed to three RWG concentrations plus one negative control, which represents the concentration allowed for inland Brazilian waters and concentrations found in surface water worldwide (0.0, 0.065, 0.65, and 6.5 mg a.i./L) for 7 and 15 days. Morphological analysis revealed significant alterations in the testicular structure, particularly in Sertoli cell extensions and cytoplasmic bridges between germ cells. Subcellular compartments also displayed alterations, including dilated mitochondria and the loss of electron density and autophagic vesicles. Gene transcript levels related to autophagy and steroidogenic regulation were upregulated in exposed fish. Germ cell quality was also affected, increasing ROS (reactive oxygen species) production and DNA fragmentation. The study highlighted the RWG reproductive toxicity, providing valuable insights into understanding the morphofunctional alterations in somatic and germ cells of Danio rerio. In conclusion, the environmental relevant concentrations used in this study were toxic to male somatic and germ cells, which raises a concern about the concentrations considered safe for human and animal use.

Icariin exerts anti-tumor activity by inducing autophagy via AMPK/mTOR/ULK1 pathway in triple-negative breast cancer

BACKGROUND

Breast cancer is the most prevalent female tumor, of which triple-negative breast cancer (TNBC) accounts for about 15%. Characterized by its aggressive nature and limited treatment options, TNBC currently stands as a significant clinical challenge. This study aimed to investigate the effects of icariin (ICA) on TNBC and explore the underlying molecular mechanism.

METHODS

Cell viability was assessed using CCK-8 assay, whereas the impact of ICA on cell proliferation was determined using colony formation assay and detection of proliferating cell nuclear antigen protein. Wound healing and transwell assays were used to evaluate the effects of ICA on cell migration and invasion, respectively. Flow cytometry was used to analyze cell cycle distribution and apoptosis. Transmission electron microscopy and monodansylcaverine staining were performed to detect the induction of autophagy, whereas molecular docking was conducted to predict the potential targets associated with autophagy. The in vivo anti-tumor effects of ICA were evaluated using a TNBC 4T1 xenograft mouse model. Protein expression levels were examined using immunoblotting and immunohistochemistry.

RESULTS

In vitro, ICA effectively suppressed the viability, proliferation, migration, and invasion of TNBC cells and induced G0/G1 phase cell cycle arrest, apoptosis, and autophagy in TNBC cells by regulating the adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)/Unc-51-like kinase 1 (ULK1) signaling pathway. The knockdown of AMPK and inhibition of autophagy with 3-methyladenine reversed the effects of ICA, highlighting the importance of AMPK and autophagy in the anti-cancer mechanism of ICA. In vivo, ICA significantly inhibited TNBC growth, promoted autophagy, and regulated AMPK/mTOR/ULK1 pathway.

CONCLUSIONS

Our findings demonstrated that ICA exerts anti-cancer effects against TNBC and the associated molecular mechanisms. This study will help to facilitate further preclinical and clinical investigations for the treatment of TNBC.

Impact of plastic-related compounds on the gene expression signature of HepG2 cells transfected with CYP3A4

The presence of plastic and microplastic within the oceans as well as in marine flora and fauna have caused a multitude of problems that have been the topic of numerous investigations for many years. However, their impact on human health remains largely unknown. Such plastic and microplastic particles have been detected in blood and placenta, underlining their ability to enter the human body. Plastics also contain other compounds, such as plasticizers, antioxidants, or dyes, whose impact on human health is currently being studied. Critical enzymes within the metabolism of endogenous molecules, especially of xenobiotics, are the cytochrome P450 monooxygenases (CYPs). Although their importance in maintaining cellular balance has been confirmed, their interactions with plastics and related products are poorly understood. In this study, the possible relationship between different plastic-related compounds and CYP3A4 as one of the most important CYPs was analyzed using hepatic cells overexpressing this enzyme. Beginning with virtual compound screening and molecular docking of more than 1000 plastic-related compounds, several candidates were identified to interact with CYP3A4. In a second step, RNA-sequencing was used to study in detail the transcriptome-wide gene expression levels affected by the selected compounds. Three candidate molecules ((2,2'-methylenebis(6-tert-butyl-4-methylphenol), 1,1-bis(3,5-di-tert-butyl-2-hydroxyphenyl)ethane, and 2,2'-methylenebis(6-cyclohexyl-4-methylphenol)) had an excellent binding affinity to CYP3A4 in-silico as well as cytotoxic effects and interactions with several metabolic pathways in-vitro. We identified common pathways influenced by all three selected plastic-related compounds. In particular, the suppression of pathways related to mitosis and 'DNA-templated DNA replication' which were confirmed by cell cycle analysis and single-cell gel electrophoresis. Furthermore, several mis-regulated metabolic and inflammation-related pathways were identified, suggesting the induction of hepatotoxicity at different levels. These findings imply that these compounds may cause liver problems subsequently affecting the entire organism.

Diabetes-induced male infertility: potential mechanisms and treatment options

Male infertility is a physiological phenomenon in which a man is unable to impregnate a fertile woman during a 12-month period of continuous, unprotected sexual intercourse. A growing body of clinical and epidemiological evidence indicates that the increasing incidence of male reproductive problems, especially infertility, shows a very similar trend to the incidence of diabetes within the same age range. In addition, a large number of previous in vivo and in vitro experiments have also suggested that the complex pathophysiological changes caused by diabetes may induce male infertility in multiple aspects, including hypothalamic-pituitary-gonadal axis dysfunction, spermatogenesis and maturation disorders, testicular interstitial cell damage erectile dysfunction. Based on the above related mechanisms, a large number of studies have focused on the potential therapeutic association between diabetes progression and infertility in patients with diabetes and infertility, providing important clues for the treatment of this population. In this paper, we summarized the research results of the effects of diabetes on male reproductive function in recent 5 years, elaborated the potential pathophysiological mechanisms of male infertility induced by diabetes, and reviewed and prospected the therapeutic measures.

Mechanistic aspects of ameliorative effects of Eicosapentanoic acid ethyl ester on methotrexate-evoked testiculopathy in rats

Disrupted spermatogenesis and testicular injury are among the devastating outcomes of methotrexate. A major contributor to methotrexate-induced testiculopathy is oxidative damage which triggers apoptosis and altered autophagy responses. Eicosapentaenoic acid ethyl ester (EPA-E) is an antihyperlipidemic derivative of omega-3 fatty acids that exhibited affinity to peroxisome proliferator-activated receptor-γ (PPAR-γ) that possesses both antioxidant and autophagy modulating properties. This is an exploratory study aiming at assessing the effectiveness of EPA-E to alleviate testicular damage induced by methotrexate. The specific exploratory hypothesis of this experiment is: EPA-E administration for 1 week to methotrexate-treated rats reduces testicular damage compared to control rats. As a secondary outcome, we were interested in identifying the implicated mechanism that mediates the action of EPA-E. In adult male Wistar rats, testiculopathy was achieved by a single methotrexate injection (20 mg/kg, ip). Rats received vehicle, EPA-E (0.3 g/kg/day, po) alone or with selective PPAR-γ antagonist (bisphenol A diglycidyl ether, BADGE) at 30 mg/kg/day, ip for 1 week. EPA-E recuperated methotrexate-attenuated serum total testosterone while reduced testicular inflammation and oxidative stress, restoring superoxide dismutase (SOD) while reducing malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Methotrexate-induced testicular apoptosis (caspase-3 and p53) was suppressed upon EPA-E treatment. Besides, EPA-E curbed methotrexate-induced abnormal autophagy by downregulating LC3A/B and beclin-1. Interestingly, BADGE-coadministration reversed EPA-E beneficial actions. Collectively, our findings suggest PPAR-γ role in EPA-E-mediated mitigation of methotrexate-evoked testiculopathy via suppression of oxidative stress, apoptosis, as well as abnormal autophagy. Furthermore, EPA-E could be used as a preventive therapy for some testiculopathies mediated by oxidative stress.

Cantharidin-induced toxic injury, oxidative stress, and autophagy attenuated by Astragalus polysaccharides in mouse testis

Cantharidin (CTD) is a chemical constituent derived from Mylabris and has good antitumor effects, but its clinical use is restricted by its inherent toxicity. However, few researches have reported its reproductive toxicity and mechanisms. This study aims to assess CTD's toxicity on mouse testes and the protective effect of Astragalus polysaccharides (APS). Briefly, biochemical analysis, histopathology, transmission electron microscopy, immunohistochemistry, and Western blotting were used to evaluate the oxidative damage of mouse testicular tissue after exposure to CTD and treatment by APS. Our research suggests a dramatic decrease in testicular index and serum testosterone levels after CTD exposure. The testis showed obvious oxidative damage accompanied by an increase in mitochondrial autophagy, the Nfr2-Keap1 pathway was inhibited, and the blood-testis barrier was destroyed. Notably, these changes were significantly improved after APS treatment. The internal mechanisms of APS ameliorate CTD-induced testicular oxidative damage in mice may be closely connected to regulatory the Nrf2-Keap1 signaling pathway, restraining autophagy, and repairing the blood-testis barrier, providing theoretical support for further study on the reproductive toxicity mechanism of CTD and clinical treatments to ameliorate it.

The constructive and destructive impact of autophagy on both genders' reproducibility, a comprehensive review

Reproduction is characterized by a series of massive renovations at molecular, cellular, and tissue levels. Recent studies have strongly tended to reveal the involvement of basic molecular pathways such as autophagy, a highly conserved eukaryotic cellular recycling, during reproductive processes. This review comprehensively describes the current knowledge, updated to September 2022, of autophagy contribution during reproductive processes in males including spermatogenesis, sperm motility and viability, and male sex hormones and females including germ cells and oocytes viability, ovulation, implantation, fertilization, and female sex hormones. Furthermore, the consequences of disruption in autophagic flux on the reproductive disorders including oligospermia, azoospermia, asthenozoospermia, teratozoospermia, globozoospermia, premature ovarian insufficiency, polycystic ovarian syndrome, endometriosis, and other disorders related to infertility are discussed as well.Abbreviations: AKT/protein kinase B: AKT serine/threonine kinase; AMPK: AMP-activated protein kinase; ATG: autophagy related; E2: estrogen; EDs: endocrine disruptors; ER: endoplasmic reticulum; FSH: follicle stimulating hormone; FOX: forkhead box; GCs: granulosa cells; HIF: hypoxia inducible factor; IVF: in vitro fertilization; IVM: in vitro maturation; LCs: Leydig cells; LDs: lipid droplets; LH: luteinizing hormone; LRWD1: leucine rich repeats and WD repeat domain containing 1; MAP1LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MTOR: mechanistic target of rapamycin kinase; NFKB/NF-kB: nuclear factor kappa B; P4: progesterone; PCOS: polycystic ovarian syndrome; PDLIM1: PDZ and LIM domain 1; PI3K: phosphoinositide 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns3K: class III phosphatidylinositol 3-kinase; POI: premature ovarian insufficiency; ROS: reactive oxygen species; SCs: Sertoli cells; SQSTM1/p62: sequestosome 1; TSGA10: testis specific 10; TST: testosterone; VCP: vasolin containing protein.

Cypermethrin induces endoplasmic reticulum stress and autophagy, leads to testicular dysfunction

Cypermethrin is a pyrethroid insecticide that is used to control insects and protect crops. However, pesticide residues and their possible toxicity to non-target animals such as mammals are concerning. Although cypermethrin reduces testosterone levels, the molecular mechanisms involved, particularly those regarding endoplasmic reticulum (ER) stress and autophagy regulation, have not yet been fully elucidated. In this study, we demonstrated testicular toxicity of cypermethrin in mouse Leydig (TM3) and Sertoli (TM4) cells. Cypermethrin suppresses TM3 and TM4 cell proliferation and induces apoptosis. Moreover, it interrupted calcium homeostasis in intracellular organelles and dissipated mitochondrial membrane polarization in mouse testicular cells. Moreover, we verified the accumulation of Sqstm1/p62 protein in the mitochondria of cypermethrin-treated TM3 and TM4 cells. Furthermore, we confirmed that cypermethrin activated autophagy and the ER stress pathway in a time-dependent manner in both cell types. Finally, we determined that cypermethrin downregulated testicular function-related genes, steroidogenesis, and spermatogenesis in mouse testis cells. Therefore, we conclude that cypermethrin regulates autophagy and ER stress, leading to testicular dysfunction.

Pentacyclic triterpene-amino acid derivatives induced apoptosis and autophagy in tumor cells, affected the JNK and PI3K/AKT/mTOR pathway

A series of pentacyclic triterpene-amino acid derivatives were synthesized and tested for anti-proliferative activity. The results showed that most of the target compounds had good anti-proliferative activity. 2c did not contain protecting groups and hydrochloride, had excellent cytotoxicity, so it had been selected for further study in the mechanism of action in T24 cells. The data from transcriptome sequencing indicated that 2c was found to be closely related to apoptosis and autophagy. Observation of fluorescence staining and analysis from flow cytometry demonstrated that 2c induced apoptosis and cause cell cycle arrest in S/G2 phase in T24 cells. Molecular mechanism studies exhibited that 2c induced apoptosis in the intrinsic and extrinsic pathways. 2c also induced cellular autophagy in T24 cells. Results from Western Blotting showed that 2c could activate JNK pathway and inhibit PI3K/AKT/mTOR pathway. In conclusion, 2c was deserved further investigation in the field of anti-tumor.

Autophagy, a critical element in the aging male reproductive disorders and prostate cancer: a therapeutic point of view

Autophagy is a highly conserved, lysosome-dependent biological mechanism involved in the degradation and recycling of cellular components. There is growing evidence that autophagy is related to male reproductive biology, particularly spermatogenic and endocrinologic processes closely associated with male sexual and reproductive health. In recent decades, problems such as decreasing sperm count, erectile dysfunction, and infertility have worsened. In addition, reproductive health is closely related to overall health and comorbidity in aging men. In this review, we will outline the role of autophagy as a new player in aging male reproductive dysfunction and prostate cancer. We first provide an overview of the mechanisms of autophagy and its role in regulating male reproductive cells. We then focus on the link between autophagy and aging-related diseases. This is followed by a discussion of therapeutic strategies targeting autophagy before we end with limitations of current studies and suggestions for future developments in the field.

Oxidative Stress, Cytotoxic and Inflammatory Effects of Azoles Combinatorial Mixtures in Sertoli TM4 Cells

Triazole and imidazole fungicides are an emerging class of contaminants with an increasing and ubiquitous presence in the environment. In mammals, their reproductive toxicity has been reported. Concerning male reproduction, a combinatorial activity of tebuconazole (TEB; triazole fungicide) and econazole (ECO; imidazole compound) in inducing mitochondrial impairment, energy depletion, cell cycle arrest, and the sequential activation of autophagy and apoptosis in Sertoli TM4 cells (SCs) has recently been demonstrated. Given the strict relationship between mitochondrial activity and reactive oxygen species (ROS), and the causative role of oxidative stress (OS) in male reproductive dysfunction, the individual and combined potential of TEB and ECO in inducing redox status alterations and OS was investigated. Furthermore, considering the impact of cyclooxygenase (COX)-2 and tumor necrosis factor-alpha (TNF-α) in modulating male fertility, protein expression levels were assessed. In the present study, we demonstrate that azoles-induced cytotoxicity is associated with a significant increase in ROS production, a drastic reduction in superoxide dismutase (SOD) and GSH-S-transferase activity levels, and a marked increase in the levels of oxidized (GSSG) glutathione. Exposure to azoles also induced COX-2 expression and increased TNF-α production. Furthermore, pre-treatment with N-acetylcysteine (NAC) mitigates ROS accumulation, attenuates COX-2 expression and TNF-α production, and rescues SCs from azole-induced apoptosis, suggesting a ROS-dependent molecular mechanism underlying the azole-induced cytotoxicity.

Role of Macroautophagy in Mammalian Male Reproductive Physiology

Physiologically, autophagy is an evolutionarily conserved and self-degradative process in cells. Autophagy carries out normal physiological roles throughout mammalian life. Accumulating evidence shows autophagy as a mechanism for cellular growth, development, differentiation, survival, and homeostasis. In male reproductive systems, normal spermatogenesis and steroidogenesis need a balance between degradation and energy supply to preserve cellular metabolic homeostasis. The main process of autophagy includes the formation and maturation of the phagophore, autophagosome, and autolysosome. Autophagy is controlled by a group of autophagy-related genes that form the core machinery of autophagy. Three types of autophagy mechanisms have been discovered in mammalian cells: macroautophagy, microautophagy, and chaperone-mediated autophagy. Autophagy is classified as non-selective or selective. Non-selective macroautophagy randomly engulfs the cytoplasmic components in autophagosomes that are degraded by lysosomal enzymes. While selective macroautophagy precisely identifies and degrades a specific element, current findings have shown the novel functional roles of autophagy in male reproduction. It has been recognized that dysfunction in the autophagy process can be associated with male infertility. Overall, this review provides an overview of the cellular and molecular basics of autophagy and summarizes the latest findings on the key role of autophagy in mammalian male reproductive physiology.

1,25-Dihydroxycholecalciferol down-regulates 3-mercaptopyruvate sulfur transferase and caspase-3 in rat model of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the commonest cause of liver morbidity and mortality and has multiple unclear pathogenic mechanisms. Vitamin D deficiency was associated with increased incidence and severity of NAFLD. Increased hepatic expression of 3-mercaptopyruvate sulfur transferase (MPST) and dysregulated hepatocyte apoptosis were involved in NAFLD pathogenesis. We aimed to explore the protective effect of 1,25-Dihydroxycholecalciferol (1,25-(OH)₂ D3) against development of NAFLD and the possible underlying mechanisms, regarding hepatic MPST and caspase-3 expression. 60 male adult rats were divided into 4 and 12 week fed groups; each was subdivided into control, high-fat diet (HFD), and HFD + VD. Serum levels of lipid profile parameters, liver enzymes, insulin, glucose, C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and hepatic levels of malondialdehyde (MDA), total antioxidant capacity (TAC), and reactive oxygen species (ROS) were measured. BMI and HOMA-IR were calculated, and liver tissues were processed for histopathological and immunohistochemical studies. The present study found that 1,25-(OH)₂ D3 significantly decreased BMI, HOMA-IR, serum levels of glucose, insulin, liver enzymes, lipid profile parameters, CRP, TNF-α, hepatic levels of MDA, ROS, hepatic expression of MPST, TNF-α, 8-hydroxy-2'-deoxyguanosine (8-OHdG), and caspase-3; and significantly increased hepatic TAC in both HFD-fed groups. In conclusion: Administration of 1,25-(OH)₂ D3 with HFD abolished the NAFLD changes associated with HFD in 4-week group, and markedly attenuated the changes in 12-week group. The anti-apoptotic effect via decrement of caspase-3 and MPST expression are novel mechanisms suggested to be implicated in the protective effect of 1,25-(OH)₂ D3.

The role of stimulator of interferon genes-mediated AMPK/mTOR/P70S6K autophagy pathway in cyfluthrin-induced testicular injury

Cyfluthrin is widely used in the field of sanitary pest control by its wide insecticidal spectrum, high efficiency and low toxicity, low residue, and good biodegradability. But, as a double-edged sword, a large amount of cyfluthrin remains are still in the environment. The residual cyfluthrin is absorbed into the food chain through vegetation and then poses a risk to soil organisms and human health. Several studies have suggested that cyfluthrin is one of the main factors causing testicular damage, but the mechanism remains unclear. In this study, we established in vivo and in vitro models of testicular injury in rats and GC-2 cells exposed to cyfluthrin to explore whether stimulator of interferon genes (STING) gene mediates the regulation of AMPK/mTOR/p70S6K autophagy pathway, which lays a foundation for further study of the mechanism of testicular injury induced by cyfluthrin. The results showed that the activity of super oxide dismutase in testis decreased and the activity of malonic dialdehyde increased with the increase of concentration in vivo and in vitro. At the same time, the levels of mitochondrial damage and inflammation in the testis also increased, which further activated autophagy. In this process, the increased level of inflammation is related to the increased expression of STING gene, and AMPK/mTOR/p70S6K autophagy pathway is also involved. To sum up, cyfluthrin has certain reproductive toxicity, and long-term exposure can induce testicular cell damage. STING gene can participate in cyfluthrin-induced testicular injury through AMPK/mTOR/P70S6K autophagy pathway.

Inhibition of VDAC1 prevents oxidative stress and apoptosis induced by bisphenol A in spermatogonia via AMPK/mTOR signaling pathway

Bisphenol A (BPA), one of the main components of industrial products, is clinically associated with the increased male infertility rate. However, the underlying molecular mechanism of the BPA-resulted reproductive toxicity is not fully elucidated. Voltage-dependent anion channel 1 (VDAC1) is a pore protein and located at the outer mitochondrial membrane. As a mitochondrial gatekeeper, VDAC1 controls the release of reactive oxygen species (ROS) and the metabolic and energetic functions of mitochondria, and serves as a critical player in mitochondrial-mediated apoptosis. Herein, we explored the role of VDAC1 in BPA-induced apoptosis of spermatogonia. The results showed that BPA increased spermatogonia cell line GC-1 spg cell apoptosis and intracellular ROS level, and suppressed AMPK/mTOR signaling pathway at a dose of 80 μM for 48 hr. Lentivirus-mediated short hairpin RNA targeting VDAC1 (Lv-shVDAC1) silenced VDAC1 expression and enhanced BPA-restricted cell viability. Knockdown of VDAC1 inhibited the apoptosis of BPA-treated GC-1 spg cells determined by with changes of the expressions of pro-apoptotic and anti-apoptotic proteins. Knockdown of VDAC1 also alleviated the BPA-triggered intracellular ROS generation and oxidative stress. Moreover, silence of VDAC1 increased AMPKα1/2 phosphorylation and suppressed mTOR phosphorylation under BPA exposure. Dorsomorphin, an AMPK inhibitor, partially abolished the effects of VDAC1 gene silencing on BPA-stimulated GC-1 spg cells. In conclusion, inhibition of VDAC1 attenuated the BPA-induced oxidative stress and apoptosis and promoted the cell viability in spermatogonia through modulating AMPK/mTOR signaling pathway.

Bridging the gap of axonal regeneration in the central nervous system: A state of the art review on central axonal regeneration

Neuronal regeneration in the central nervous system (CNS) is an important field of research with relevance to all types of neuronal injuries, including neurodegenerative diseases. The glial scar is a result of the astrocyte response to CNS injury. It is made up of many components creating a complex environment in which astrocytes play various key roles. The glial scar is heterogeneous, diverse and its composition depends upon the injury type and location. The heterogeneity of the glial scar observed in different situations of CNS damage and the consequent implications for axon regeneration have not been reviewed in depth. The gap in this knowledge will be addressed in this review which will also focus on our current understanding of central axonal regeneration and the molecular mechanisms involved. The multifactorial context of CNS regeneration is discussed, and we review newly identified roles for components previously thought to solely play an inhibitory role in central regeneration: astrocytes and p75NTR and discuss their potential and relevance for deciding therapeutic interventions. The article ends with a comprehensive review of promising new therapeutic targets identified for axonal regeneration in CNS and a discussion of novel ways of looking at therapeutic interventions for several brain diseases and injuries.

Development of physiologically-based toxicokinetic-toxicodynamic (PBTK-TD) model for 4-nonylphenol (4-NP) reflecting physiological changes according to age in males: Application as a new risk assessment tool with a focus on toxicodynamics

Environmental exposure to 4-nonylphenol (4-NP) is extensive, and studies related to human risk assessment must continue. Especially, prediction of toxicodynamics (TDs) related to reproductive toxicity in males is very important in risk-level assessment and management of 4-NP. This study aimed to develop a physiologically-based-toxicokinetic-toxicodynamic (PBTK-TD) model that added a TD prostate model to the previously reported 4-n-nonylphenol (4-n-NP) physiologically-based-pharmacokinetic (PBPK) model. Modeling was performed under the assumption of similar TKs between 4-n-NP and 4-NP because TK experiments on 4-NP, a random-mixture, are practically difficult. This study was very important to quantitatively predict the TKs and TDs of 4-NP by age at exposure using an advanced PBTK-TD model that reflected physiological-changes according to age. TD-modeling was performed based on the reported toxic effects of 4-NP on RWPE-1 cells, a human-prostate-epithelial-cell-line. Through a meta-analysis of reported human physiological data, body weight, tissue volume, and blood flow rate patterns according to age were mathematically modeled. These relationships were reflected in the PBTK-TD model for 4-NP so that the 4-NP TK and TD changes according to age and their differences could be confirmed. Differences in TK and TD parameters of 4-NP at various ages were not large, within 3.61-fold. Point-of-departure (POD) and reference-doses for each age estimated using the model varied as 426.37-795.24 and 42.64-79.52 μg/kg/day, but the differences (in POD or reference doses between ages) were not large, at less than 1.87-times. The PBTK-TD model simulation predicted that even a 100-fold 4-NP POD_man dose would not have large toxicity to the prostate. With a focus on TDs, the predicted maximum possible exposure of 4-NP was as high as 6.06-23.60 mg/kg/day. Several toxicity-related values estimated by the dose-response curve were higher than those calculated, depending upon the PK or TK, which would be useful as a new exposure limit for prostate toxicity of 4-NP.

Interaction between apoptosis and autophagy in testicular function

Several processes including oxidative stress, apoptosis, inflammation and autophagy are related to testicular function. Recent studies indicate that a crosstalk between apoptosis and autophagy is essential in regulating testicular function. Autophagy and apoptosis communicate with each other in a complex way, allowing them to work for or against each other in testicular cell survival and death. Several xenobiotics especially endocrine-disrupting chemicals (EDCs) have caused reproductive toxicity because of their potential to modify the rate of autophagy and trigger apoptosis. Therefore, the purpose of the present review was to shed light on how autophagy and apoptosis interact together in the testis.

Nonylphenol inhibited HIF-1alpha regulated aerobic glycolysis and induced ROS mediated apoptosis in rat Sertoli cells

Nonylphenol (NP) is an endocrine disruptor with reproductive toxicity, which can induce apoptosis of Sertoli cells (SCs). SCs have a high aerobic glycolytic flux to ensure sufficient lactate for germ cells as central energy metabolite, and hypoxia-inducible factors 1alpha (HIF-1α) is a major regulator of glycolysis. This study aimed to investigate whether NP can alter HIF-1α-regulated aerobic glycolysis metabolism and thus induce apoptosis in rat SCs. The results revealed that cell viability, intracellular and extracellular lactate levels, the expression of Hk2, Ldha and Mct4, and the protein levels of HIF-1α, HK2, LDHA and MCT4 were decreased significantly when rat SCs exposed to 20 and 30 μM NP for 24 h. Compared with the 30 μM NP group, the protein levels of HIF-1α, HK2 and LDHA, the expression of Hk2 and Ldha and intracellular lactate levels were increased in 30 μM NP and 125 μM cobalt chloride (CoCl₂, inhibitor of HIF-1α proteasome-mediated degradation) co-treated group. Furthermore, the elevation of reactive oxygen species (ROS) and apoptosis induced by 30 μM NP were also reversed. In summary, exposure to NP inhibited the ability of SCs to produce and secrete lactate. Meanwhile, NP exposure could lead to a decrease in HIF-1α thereby inhibiting aerobic glycolysis in rat SCs, disrupting intracellular homeostasis and further inducing ROS-mediated apoptosis. This research is the first to explore the NP toxicity on SCs function with respect to nutrition support to germ cells, and provide new evidence on the inhibition of aerobic glycolysis inducing ROS-mediated apoptosis in SCs.

4-[1-Ethyl-1-methylhexy]-phenol induces apoptosis and interrupts Ca2+ homeostasis via ROS pathway in Sertoli TM4 cells

Biological effect of an individual nonylphenol (NP) isomer extremely relies upon the side chain structure. This research was designed to evaluate the impact of NP isomer, 4-[1-ethyl-1-methylhexy]-phenol (NP₆₅), on Sertoli cells in vitro. Sertoli TM4 cells were exposed to various concentration (0, 0.1, 1, 10, or 20 μM) of NP₆₅ for 24 h, and the outcomes indicated that treatment of NP₆₅ induced reactive oxygen species (ROS) generation, oxidative stress, and apoptosis for Sertoli TM4 cells. In addition, it was found that NP₆₅ exposure affected homeostasis of Ca²⁺ in Sertoli TM4 cells by increasing cytoplasm [Ca²⁺]i, inhibiting Ca²⁺-ATPase activity and decreasing cyclic adenosine monophosphate (cAMP) concentration. Pretreatment with ROS scavenger, N-acetylcysteine (NAC), attenuated NP₆₅-induced oxidative stress as well as apoptosis for TM4 cells. Furthermore, NAC blocked NP₆₅-induced disorders of Ca²⁺ homeostasis by attenuating the growth of intracellular [Ca²⁺]i and the inhibition of Ca²⁺-ATPase and cAMP activities. Thus, we have demonstrated that NP₆₅ induced apoptosis as well as acted as a potent inhibitor of Ca²⁺-ATPase activity and resulted in disorder of Ca²⁺ homeostasis in Sertoli TM4 cells; ROS participated in the process. Our results supported the view that oxidative stress acted an essential role within the development of apoptosis and Ca²⁺ overload in TM4 cells as a consequence of NP₆₅ stimulation.

Allethrin Promotes Apoptosis and Autophagy Associated with the Oxidative Stress-Related PI3K/AKT/mTOR Signaling Pathway in Developing Rat Ovaries

The increased concern regarding the reduction in female fertility and the impressive numbers of women undergoing fertility treatment support the existence of environmental factors beyond inappropriate programming of developing ovaries. Among these factors are pyrethroids, which are currently some of the most commonly used pesticides worldwide. The present study was performed to investigate the developmental effects of the pyrethroid-based insecticide allethrin on ovarian function in rat offspring in adulthood. We mainly focused on the roles of oxidative stress, apoptosis, autophagy and the related pathways in ovarian injury. Thirty-day-old Wistar albino female rats were intragastrically administered 0 (control), 34.2 or 68.5 mg/kg body weight allethrin after breeding from Day 6 of pregnancy until delivery. We found that allethrin-induced ovarian histopathological damage was accompanied by elevations in oxidative stress and apoptosis. Interestingly, the number of autophagosomes in allethrin-treated ovaries was higher, and this increase was correlated with the upregulated expression of genes and proteins related to the autophagic marker LC-3. Furthermore, allethrin downregulated the expression of PI3K, AKT and mTOR in allethrin-treated ovaries compared with control ovaries. Taken together, the findings of this study suggest that exposure to the pyrethroid-based insecticide allethrin adversely affects both the follicle structure and function in rat offspring during adulthood. Specifically, allethrin can induce excessive oxidative stress and defective autophagy-related apoptosis, probably through inactivation of the PI3K/AKT/mTOR signaling pathway, and these effects may contribute to ovarian dysfunction and impaired fertility in female offspring.

Synergistic Activity of Ketoconazole and Miconazole with Prochloraz in Inducing Oxidative Stress, GSH Depletion, Mitochondrial Dysfunction, and Apoptosis in Mouse Sertoli TM4 Cells

Triazole and imidazole fungicides represent an emerging class of pollutants with endocrine-disrupting properties. Concerning mammalian reproduction, a possible causative role of antifungal compounds in inducing toxicity has been reported, although currently, there is little evidence about potential cooperative toxic effects. Toxicant-induced oxidative stress (OS) may be an important mechanism potentially involved in male reproductive dysfunction. Thus, to clarify the molecular mechanism underlying the effects of azoles on male reproduction, the individual and combined potential of fluconazole (FCZ), prochloraz (PCZ), miconazole (MCZ), and ketoconazole (KCZ) in triggering in vitro toxicity, redox status alterations, and OS in mouse TM4 Sertoli cells (SCs) was investigated. In the present study, we demonstrate that KCZ and MCZ, alone or in synergistic combination with PCZ, strongly impair SC functions, and this event is, at least in part, ascribed to OS. In particular, azoles-induced cytotoxicity is associated with growth inhibitory effects, G0/G1 cell cycle arrest, mitochondrial dysfunction, reactive oxygen species (ROS) generation, imbalance of the superoxide dismutase (SOD) specific activity, glutathione (GSH) depletion, and apoptosis. N-acetylcysteine (NAC) inhibits ROS accumulation and rescues SCs from azole-induced apoptosis. PCZ alone exhibits only cytostatic and pro-oxidant properties, while FCZ, either individually or in combination, shows no cytotoxic effects up to 320 µM.

Protective effect of polysaccharides from Ostrea rivularis against reproductive injury via regulating autophagy induced by oxidative stress

The objective of this study was to investigate the effect of polysaccharides from Ostrea rivularis (ORP) relieving reproductive damage by regulating autophagy. The results showed that ORP intervention could alleviate the pathological changes of the testis and alleviate oxidative stress which were caused by cyclophosphamide (CTX) in vivo, including improve sperm symptoms and rise testosterone level. Reduced level of autophagy after ORP intervention was observed by transmission electron microscopy (TEM), which implied that ORP might regulate cell autophagy. In vitro experiments showed that ORP could alleviate the damage of TM4 cells induced by H₂O₂, reduce the level of intracellular ROS and the content of MDA. Autophagy-related protein expressions of p62, LC3, Beclin-1 before and after 3-MA inhibitor intervention were also proved that ORP could regulate autophagy. Overall, these results confirmed that ORP could reduce reproductive damage related to autophagy.

Mammalian AKT, the Emerging Roles on Mitochondrial Function in Diseases

Mitochondrial dysfunction may play a crucial role in various diseases due to its roles in the regulation of energy production and cellular metabolism. Serine/threonine kinase (AKT) is a highly recognized antioxidant, immunomodulatory, anti-proliferation, and endocrine modulatory molecule. Interestingly, increasing studies have revealed that AKT can modulate mitochondria-mediated apoptosis, redox states, dynamic balance, autophagy, and metabolism. AKT thus plays multifaceted roles in mitochondrial function and is involved in the modulation of mitochondria-related diseases. This paper reviews the protective effects of AKT and its potential mechanisms of action in relation to mitochondrial function in various diseases.

Chronic exposure to nonylphenol induces oxidative stress and liver damage in male zebrafish (Danio rerio): Mechanistic insight into cellular energy sensors, lipid accumulation and immune modulation

Nonylphenol (NP), an environmentally persistent and toxic endocrine-disrupting chemical with estrogenic properties, has severe implications on humans and wildlife. Accumulating evidence demonstrates the toxic response of NP on the developmental process, nervous system, and reproductive parameters. Although NP exposure has been implicated in chronic liver injury, the underlying events associated with hepatic pathophysiology remain less investigated. Using male zebrafish (Danio rerio) as the model, the present study investigates the impact of environmentally relevant concentrations of NP (50 and 100 μg/L, 21 days) on hepatic redox homeostasis vis-à-vis cellular energy sensors, inflammatory response, and cell death involving a mechanistic insight into estrogen receptor (ER) modulation. Our results demonstrate that congruent with significant alteration in transcript abundance of antioxidant enzymes (SOD1, SOD2, Catalase, GPx1a, GSTα1), chronic exposure to NP promotes ROS synthesis, more specifically superoxide anions and H₂O₂ levels, and lipid peroxidation potentially through elevated NOX4 expression. Importantly, NP perturbation of markers associated with fatty acid biosynthesis (srebf1/fasn) and cellular energy-sensing network (sirt1/ampkα/pgc1α) indicates dysregulated energy homeostasis, metabolic disruption, and macrovesicular steatosis, albeit with differential sensitivity at the dose level tested. Besides, elevated p38-MAPK phosphorylation (activation) together with loss of ER homeostasis at both mRNA (esr1, esr2a, esr2b) and protein (ERα, ERβ) levels suggest that NP modulation of ER abundance may have a significant influence on hepatic events. Elevated expression of inflammatory markers (TLR4, p-NF-κB, TNF-α, IL-6, IL-1β, and NOS2) and pro-apoptotic and necrotic regulators, e.g., Bax, caspase- 8, -9 and cleaved PARP1 (50 kDa), indicate chronic inflammation and hepatotoxicity in NP-exposed males. Collectively, elevated oxidative stress, metabolic dysregulation and immune modulation may lead to chronic liver injury in organisms exposed to metabolic disrupting chemicals.

Bacterial Infections Affect Male Fertility: A Focus on the Oxidative Stress-Autophagy Axis

Numerous factors trigger male infertility, including lifestyle, the environment, health, medical resources and pathogenic microorganism infections. Bacterial infections of the male reproductive system can cause various reproductive diseases. Several male reproductive organs, such as the testicles, have unique immune functions that protect the germ cells from damage. In the reproductive system, immune cells can recognize the pathogen-associated molecular patterns carried by pathogenic microorganisms and activate the host's innate immune response. Furthermore, bacterial infections can lead to oxidative stress through multiple signaling pathways. Many studies have revealed that oxidative stress serves dual functions: moderate oxidative stress can help clear the invaders and maintain sperm motility, but excessive oxidative stress will induce host damage. Additionally, oxidative stress is always accompanied by autophagy which can also help maintain host homeostasis. Male reproductive system homeostasis disequilibrium can cause inflammation of the genitourinary system, influence spermatogenesis, and even lead to infertility. Here, we focus on the effect of oxidative stress and autophagy on bacterial infection in the male reproductive system, and we also explore the crosslink between oxidative stress and autophagy during this process.

The Molecular Mechanisms of Phytophthora infestans in Response to Reactive Oxygen Species Stress

Reactive oxygen species (ROSs) are critical for the growth, development, proliferation, and pathogenicity of microbial pathogens; however, excessive levels of ROSs are toxic. Little is known about the signaling cascades in response to ROS stress in oomycetes such as Phytophthora infestans, the causal agent of potato late blight. Here, P. infestans was used as a model system to investigate the mechanism underlying the response to ROS stress in oomycete pathogens. Results showed severe defects in sporangium germination, mycelium growth, appressorium formation, and virulence of P. infestans in response to H₂O₂ stress. Importantly, these phenotypes mimic those of P. infestans treated with rapamycin, the inhibitor of target of rapamycin (TOR, 1-phosphatidylinositol-3-kinase). Strong synergism occurred when P. infestans was treated with a combination of H₂O₂ and rapamycin, suggesting that a crosstalk exists between ROS stress and the TOR signaling pathway. Comprehensive analysis of transcriptome, proteome, and phosphorylation omics showed that H₂O₂ stress significantly induced the operation of the TOR-mediated autophagy pathway. Monodansylcadaverine staining showed that in the presence of H₂O₂ and rapamycin, the autophagosome level increased in a dosage-dependent manner. Furthermore, transgenic potatoes containing double-stranded RNA of TOR in P. infestans (PiTOR) displayed high resistance to P. infestans. Therefore, TOR is involved in the ROS response and is a potential target for control of oomycete diseases, because host-mediated silencing of PiTOR increases potato resistance to late blight.

Lipophagy mediated glucose-induced changes of lipid deposition and metabolism via ROS dependent AKT-Beclin1 activation

High dietary carbohydrate intake leads to lipid accumulation in the intestinal tract, but the molecular mechanism remains unknown. In the present study, using yellow catfish (Pelteobagrus fulvidraco) as a model, we found that (1) high carbohydrate diets (HCD) and high glucose (HG) increased lipid deposition, up-regulated lipogenesis and fatty acid β-oxidation, activated autophagy and induced oxidative stress in the intestinal tissues and intestinal epithelial cells (IECs); (2) lipophagy alleviated HG-induced lipid accumulation via the up-regulation of fatty acid β-oxidation; (3) Akt interacted directly with Beclin1; (4) HG suppressed Akt1 phosphorylation, downregulated Akt1-mediated phosphorylation of Beclin1, activated lipophagy and alleviated the increment of TG deposition induced by HG with S87 and S292 being the key phosphorylation residues of Beclin1 in response to HG; (5) ROS generation mediated HG-induced activation of lipophagy and HG-induced suppression of AKT phosphorylation, activated AMPK and alleviated HG-induced increase of TG deposition. Our study provides mechanistic evidence that high carbohydrate- and glucose-induced lipophagy in intestine and IECs is associated with ROS-AKT-Beclin1-dependent activation of autophagy, which alleviates glucose-induced lipid accumulation. Our findings are important since the regulation of autophagy can be used as potential molecular targets for the prevention and treatment of lipotoxicity in the intestine of vertebrates, including humans.

Polystyrene microplastics induce blood-testis barrier disruption regulated by the MAPK-Nrf2 signaling pathway in rats

As a persistent pollutant, microplastics (MPs) have been reported to induce sperm quantity decrease in mice. However, the related mechanism remains obscure. Therefore, this study is intended to explore the effects of polystyrene microplastics (PS-MPs) on male reproduction and its related mechanism of blood-testis barrier (BTB) impairment. Thirty-two adult male Wistar rats were divided randomly into four groups fed with PS-MPs for 90 days at doses of 0 mg/day (control group), 0.015 mg/day, 0.15 mg/day, and 1.5 mg/day, respectively. The present results have shown that PS-MP exposure led to the damage of seminiferous tubule, resulted in apoptosis of spermatogenic cells, and decreased the motility and concentration of sperm, while the abnormality of sperm was elevated. Meanwhile, PS-MPs could induce oxidative stress and activate the p38 MAPK pathway and thus deplete the nuclear factor erythroid-2 related factor 2 (Nrf2). Noteworthily, PS-MPs led to the BTB-related protein expression decrease. All these results demonstrated that PS-MP exposure may lead to the destruction of BTB integrity and the apoptosis of spermatogenic cells through the activation of the MAPK-Nrf2 pathway. The current study provided novelty evidence for elucidating the effects of PS-MPs on male reproductive toxicity and its potential mechanism.

Proliferation, apoptosis, and number of Sertoli cells in the Syrian hamster during recrudescence after exposure to short photoperiod†‡

The Sertoli cell (Sc) has been described as a quiescent cell once the animal has reached sexual maturity. Syrian hamster is an animal that displays testicular regression due to short photoperiod, during which process germ cells and Sc are removed through apoptosis. The aim of this work was to investigate histochemically whether the spontaneous testicular recrudescence processes after exposure to a short photoperiod lead to an increase in Sc proliferative activity in order to restore the normal population. Three spontaneous recrudescence groups were established: initial (IR), advanced (AR), and total (TR) recrudescence, which were compared with animal undergoing the regression process (mild: MRg, strong: SRg, and total: TRg) and animals in long photoperiod (Controls). Histological sections were submitted to histochemical techniques for detecting apoptotic and proliferative Sc with bright-field and fluorescence microscopy. For each group, the proliferative Sc index (PScI) and apoptotic Sc index (AScI), and the total number of Sc were obtained. The results revealed the existence of Vimentin+/TUNEL+ as well as Vimentin+/PCNA+ cells. The PScI was significantly higher in TRg and IR than in the other groups. The AScI was only significantly higher in MRg and SRg with respect to the other groups. The total number of Sc increased among TRg, IR, and AR, reaching values similar to those of the Controls. In conclusion, the increase in Sc proliferation from final regression and recrudescence, accompanied by a similar rate of apoptosis to the Control group, is the cause of the restoration of the Sc population during spontaneous recrudescence.

Research Progress on the Mechanism of Mitochondrial Autophagy in Cerebral Stroke

Mitochondrial autophagy is an early defense and protection process that selectively clears dysfunctional or excessive mitochondria through a distinctive mechanism to maintain intracellular homeostasis. Mitochondrial dysfunction during cerebral stroke involves metabolic disbalance, oxidative stress, apoptosis, endoplasmic reticulum stress, and abnormal mitochondrial autophagy. This article reviews the research progress on the mechanism of mitochondrial autophagy in ischemic stroke to provide a theoretical basis for further research on mitochondrial autophagy and the treatment of ischemic stroke.

Identification of Competing Endogenous RNA and Micro-RNA Profiles and Regulatory Networks in 4-Nonylphenol-induced Impairment of Sertoli Cells

The xenoestrogens nonylphenols (NPs), which are materials used in the plastic polymer industry, are considered endocrine disruptors in a wide range of organisms. Studies have shown that human health problems, such as infertility and reproductive toxicology, are linked with NPs. However, the mechanism by which NPs interfere with male reproduction is not fully elucidated. Here, we found that 4-NP can result in male reproductive impairment and reduce androgen receptor (AR) protein levels in rat sertoli cells in vitro and in vivo. Moreover, we performed RNA sequencing to assess the differential expression of ceRNAs in rat primary sertoli cells treated with 4-NP. Bioinformatics methods, such as Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) database and ceRNA functional network analyses, were used to investigate the sequencing data and gain further understanding of the biological processes. Our analysis revealed a core set of mRNAs (Ar, Atf6 and Cbp), and circRNAs (circ673, circ1377, circ1789, and circPTEN) that were selected and validated by RT-qPCR. In addition, the head-to-tail splicing of circ673, circ1377, circ1789, and circPTEN was identified by Sanger sequencing. These findings provide the first insight into the ceRNA expression profiles of rat sertoli cells and reveal that ceRNAs participate in 4-NP-induced impairment of sertoli cell function, thereby indicating potential therapies for both reproductive toxicology and male infertility.

Effect of vitamin D3 supplementation on hepatic lipid dysregulation associated with autophagy regulatory AMPK/Akt-mTOR signaling in type 2 diabetic mice

Vitamin D3 has been reported to protect liver against non-alcoholic fatty liver disease (NAFLD) by attenuating hepatic lipid dysregulation in type 2 diabetes mellitus (T2DM). However, the mechanism of vitamin D3 on hepatic lipid metabolism-associated autophagy in hyperglycemia-induced NAFLD remains yet to be exactly elucidated. C57BL/6J mice were intraperitoneally injected with 30 mg/kg of streptozotocin and fed a high-fat diet for induction of diabetes. All mice were administered with vehicle or vitamin D3 (300 ng/kg or 600 ng/kg) by oral gavage for 12 weeks. Histological demonstrations of the hepatic tissues were obtained by H&E staining and the protein levels related to lipid metabolism and autophagy signaling were analyzed by Western blot. Treatment with vitamin D3 improved insulin resistance, liver damage, and plasma lipid profiles, and decreased hepatic lipid content in the diabetic mice. Moreover, vitamin D3 administration ameliorated hepatic lipid dysregulation by downregulating lipogenesis and upregulating lipid oxidation under diabetic condition. Importantly, vitamin D3 treatment induced autophagy by activating AMP-activated protein kinase (AMPK), inactivating Akt and ultimately blocking mammalian target of rapamycin (mTOR) activation in the T2DM mice. Additionally, vitamin D3 was found to be effective in anti-apoptosis and anti-fibrosis in the liver of diabetic mice. The results suggested that vitamin D3 may ameliorate hepatic lipid dysregulation by activating autophagy regulatory AMPK/Akt-mTOR signaling in T2DM, providing insights into its beneficial effects on NAFLD in type 2 diabetic patients.

Fluorochloridone induces autophagy in TM4 Sertoli cells: involvement of ROS-mediated AKT-mTOR signaling pathway

BACKGROUND

Fluorochloridone (FLC), a selective pyrrolidone herbicide, has been recognized as a potential endocrine disruptor and reported to induce male reproductive toxicity, but the underlying mechanism is unclear. The aim of this study was to investigate the mechanism of FLC-induced reproductive toxicity on male mice with particular emphasis on the role of autophagy in mice' TM4 Sertoli cells.

METHODS

Adult C57BL/6 mice were divided into one control group (0.5% sodium carboxymethyl cellulose), and four FLC-treated groups (3,15,75,375 mg/kg). The animals (ten mice per group) received gavage for 28 days. After treatment, histological analysis, sperm parameters, the microstructure of autophagy and the expression of autophagy-associated proteins in testis were evaluated. Furthermore, to explore the autophagy mechanism, TM4 Sertoli cells were treated with FLC (0,40,80,160 μM) in vitro for 24 h. Cell activity and cytoskeletal changes were measured by MTT assay and F-actin immunofluorescence staining. The formation of autophagosome, accumulation of reactive oxygen species (ROS), expression of autophagy marker proteins (LC3, Beclin-1 and P62) and AKT-related pathway proteins (AKT, mTOR) were observed. The ROS scavenger N-acetylcysteine (NAC) and AKT agonist (SC79) were used to treat TM4 cells to observe the changes of AKT-mTOR pathway and autophagy.

RESULTS

In vivo, it showed that FLC exposure caused testicular injuries, abnormality in epididymal sperm. Moreover, FLC increased the formation of autophagosomes, the accumulation of LC3II/LC3I, Beclin-1 and P62 protein, which is related to the degradation of autophagy. In vitro, FLC triggered TM4 cell autophagy by increasing the formation of autophagosomes and upregulating of LC3II/LC3I, Beclin-1 and P62 levels. In addition, FLC induced ROS production and inhibited the activities of AKT and mTOR kinases. The Inhibition of AKT/mTOR signaling pathways and the activation of autophagy induced by FLC could be efficiently reversed by pretreatment of NAC. Additionally, decreased autophagy and increased cell viability were observed in TM4 cells treated with SC79 and FLC, compared with FLC alone, indicating that FLC-induced autophagy may be pro-death.

CONCLUSION

Taken together, our study provided the evidence that FLC promoted autophagy in TM4 Sertoli cells and that this process may involve ROS-mediated AKT/mTOR signaling pathways.

Bisphenol A promotes autophagy in ovarian granulosa cells by inducing AMPK/mTOR/ULK1 signalling pathway

BACKGROUND

Bisphenol A (BPA) is a widespread endocrine-disrupting chemical with estrogen like effects, which could interfere with the human reproductive system by disrupting the normal function of granulosa cells (GCs) leading to abnormal ovarian function. However, the mechanism of its toxicity on human GCs has not been clearly described thus far.

METHODS

106 normogonadotropic infertile women undergoing their first in-vitro fertilization-embryo transfer (IVF-ET) cycle were recruited. Urinary BPA level and the early outcomes of IVF-ET were analysed. Patients were divided to low and high BPA exposure groups using the median urinary BPA concentration as the cut-off value. In-vivo and in-vitro studies were conducted using mice and human granulosa cell line (KGN cells). Female Kunming mice approximately 6-8 weeks of age were poisoned with BPA at different dosages (1, 10 or 100 μg/kg) by oral gavage once daily for 2 weeks, while KGN cells were exposed to BPA at the concentration of 1, 10 or 100 nM for 24 h, 48 h or 72 h. BPA-induced ovarian morphologic changes were analysed by histopathology investigation. Cell viability and apoptosis were evaluated using CCK-8, TUNEL and flowcytometric, respectively. Hormone levels were determined using ELISA and the molecular mechanism studies were conducted using immunofluorescence, RT-PCR and western blots.

RESULTS

The oocyte retrieval rate, maturation rate and embryo implantation rate significantly decreased with the higher level of urinary BPA concentration. Peak E2 level was lower in high BPA group, but no statistical significance could be observed. In BPA treated mice, cystic dilation of the follicles with a decreased number of GCs could be observed histopathologically. Decreased E2, P4 and AMH level and GCs autophagy could be detected both in-vivo and in-vitro with the activation of AMPK/mTOR/ULK1 signalling pathway. As being confirmed in KGN cells, phosphorylated AMPK and ULK1 increased while phosphorylated mTOR decreased, and by inhibition autophagy using knockdown of AMPK or 3-MA, adverse effects of BPA exposure in-vitro could be reversed.

CONCLUSION

BPA exposure might abnormally influence human ovarian functions leading to abnormal folliculogenesis by activation of autophagy in GCs through AMPK/mTOR/ULK1 pathway.

HT-2 toxin affects cell viability of goat spermatogonial stem cells through AMPK-ULK1 autophagy pathways

HT-2 toxin is widely found in moldy crops and is the major metabolite of T-2 toxin, which has been shown to exert various toxic effects in farm animals. However, little is known about the effects of HT-2 toxin on male reproduction, particularly spermatogenesis. This study aims to investigate the toxic effects of HT-2 toxin on goat spermatogonial stem cells (SSCs) and related autophagy-regulated mechanisms. Our results showed that HT-2 toxin exposure resulted in decreased cell viability and proliferation, disrupted SSCs self-renewal, and reduced germ cell-related gene expression. HT-2 toxin exposure also induced oxidative stress and cell apoptosis, as shown by ROS accumulation, increased antioxidant enzyme activity levels, decreased the mitochondrial membrane potential, and increased caspase-9 mRNA and Bcl/bax protein levels. Additionally, HT-2 toxin exposure increased the expression of the autophagy-inducing genes Atg5, Atg7 and Beclin1 and the number of autophagosomes, which indicated that HT-2 toxin induced autophagy in the goat SSCs. Moreover, we also examined a possible mechanism by which HT-2 toxin exposure induced higher expression of AMPK, mTOR and ULK at both the mRNA and protein levels. our results indicated that HT-2 toxin caused apoptosis and autophagy by activating AMPK-mTOR-ULK1 pathway, which further affected SSCs viability.

Bufei Jianpi Formula Improves Mitochondrial Function and Suppresses Mitophagy in Skeletal Muscle via the Adenosine Monophosphate-Activated Protein Kinase Pathway in Chronic Obstructive Pulmonary Disease

Skeletal muscle dysfunction, a striking systemic comorbidity of chronic obstructive pulmonary disease (COPD), is associated with declines in activities of daily living, reductions in health status and prognosis, and increases in mortality. Bufei Jianpi formula (BJF), a traditional Chinese herbal formulation, has been shown to improve skeletal muscle tension and tolerance via inhibition of cellular apoptosis in COPD rat models. This study aimed to investigate the mechanisms by which BJF regulates the adenosine monophosphate-activated protein kinase (AMPK) pathway to improve mitochondrial function and to suppress mitophagy in skeletal muscle cells. Our study showed that BJF repaired lung function and ameliorated pathological impairment in rat lung and skeletal muscle tissues. BJF also improved mitochondrial function and reduced mitophagy via the AMPK signaling pathway in rat skeletal muscle tissue. In vitro, BJF significantly improved cigarette smoke extract-induced mitochondrial functional impairment in L6 skeletal muscle cells through effects on mitochondrial membrane potential, mitochondrial permeability transition pores, adenosine triphosphate production, and mitochondrial respiration. In addition, BJF led to upregulated expression of mitochondrial biogenesis markers, including AMPK-α, PGC-1α, and TFAM and downregulation of mitophagy markers, including LC3B, ULK1, PINK1, and Parkin, with increased expression of downstream markers of the AMPK pathway, including mTOR, PPARγ, and SIRT1. In conclusion, BJF significantly improved skeletal muscle and mitochondrial function in COPD rats and L6 cells by promoting mitochondrial biogenesis and suppressing mitophagy via the AMPK pathway. This study suggests that BJF may have therapeutic potential for prophylaxis and treatment of skeletal muscle dysfunction in patients with COPD.

Nonylphenol Induces Apoptosis through ROS/JNK Signaling in a Spermatogonia Cell Line

Nonylphenol (NP) is an endocrine-disruptor chemical that negatively affects reproductive health. Testes exposure to NP results in testicular structure disruption and a reduction in testicular size and testosterone levels. However, the effects of NP on spermatogonia in testes have not been fully elucidated. In this study, the molecular mechanisms of NP in GC-1 spermatogonia (spg) cells were investigated. We found that cell viability significantly decreased and apoptosis increased in a dose-dependent manner when GC-1 spg cells were exposed to NP. Furthermore, the expression levels of the pro-apoptotic proteins increased, whereas anti-apoptosis markers decreased in NP-exposed GC-1 spg cells. We also found that NP increased reactive oxygen species (ROS) generation, suggesting that ROS-induced activation of the MAPK signaling pathway is the molecular mechanism of NP-induced apoptosis in GC-1 spg cells. Thus, NP could induce c-Jun phosphorylation; dose-dependent expression of JNK, MKK4, p53, and p38; and the subsequent inhibition of ERK1/2 and MEK1/2 phosphorylation. The genes involved in apoptosis and JNK signaling were also upregulated in GC-1 spg cells treated with NP compared to those in the controls. Our findings suggest that NP induces apoptosis through ROS/JNK signaling in GC-1 spg cells.

Wnt-3a improves functional recovery through autophagy activation via inhibiting the mTOR signaling pathway after spinal cord injury

Little is known about the effect of wnt-3a on motor nerve function and its specific molecular mechanisms after spinal cord injury (SCI). This study demonstrates that the downregulated expression levels of caspases-3, caspases-9 and chondroitin sulfate proteoglycan (CSPG) proteins and number of proportion of transferase UTP nick end labeling (TUNEL)-positive neurons by wnt-3a treatment. Then, Nissl and hematoxylin-eosin (HE) staining showed that wnt-3a significantly reduced the loss of spinal anterior horn motor neurons and promoted repair of injured spinal cord tissues after SCI. The above factors constructed a favorable microenvironment for the recovery of motor nerve function after SCI. To elucidate the molecular mechanism of neuroprotection of wnt-3a on SCI, the study showed that the expression levels of Beclin-1 and light chain (LC)3-II/I in spinal cord neurons were significantly improved by wnt-3a after SCI in vitro and vivo experiments, while the effect of wnt-3a was inhibited after mechanistic target of rapamycin (mTOR) signaling pathway being activated by MHY-1485. Besides, the level of p70S6K phosphorylation was inhibited by wnt-3a treatment, on the contrary, the level of p70S6K protein was elevated by wnt-3a, indicating that wnt-3a significantly activated neuronal autophagy by inhibiting mTOR signaling pathway after SCI. To further verify the correlation between neuroprotection of wnt-3a and autophagy, we found that after the rats and spinal cord neurons were combined treatment with wnt-3a and MHY-1485, the neuroprotection of wnt-3a on SCI was significantly inhibited. This study is the first to report that wnt-3a improves functional recovery through autophagy activation via inhibiting the mTOR signaling pathway after SCI.

Cytotoxicity of nonylphenol on spermatogonial stem cells via phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin pathway

BACKGROUND

With continuous advancement of industrial society, environmental pollution has become more and more serious. There has been an increase in infertility caused by environmental factors. Nonylphenol (NP) is a stable degradation product widely used in daily life and production and has been proven to affect male fertility. However, the underlying mechanisms therein are unclear. Thus, it is necessary to study the effect and mechanism of NP on spermatogonial stem cells (SSCs).

AIM

To investigate the cytotoxic effect of NP on SSCs via the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway.

METHODS

SSCs were treated with NP at 0, 10, 20 or 30 µmol. MTT assay was performed to evaluate the effect of NP on the proliferation of SSCs. Flow cytometry was conducted to measure SSC apoptosis. The expression of Bad, Bcl-2, cytochrome-c, pro-Caspase 9, SOX-2, OCT-4, Nanog, Nanos3, Stra8, Scp3, GFRα1, CD90, VASA, Nanos2, KIT, PLZF and PI3K/AKT/mTOR-related proteins was observed by western blot, and the mRNA expression of SOX-2, OCT-4 and Nanog was detected by quantitative reverse transcription polymerase chain reaction.

RESULTS

Compared with untreated cells (0 μmol NP), SSCs treated with NP at all concentrations showed a decrease in cell proliferation and expression of Bcl-2, Nanog, OCT-4, SOX-2, Nanos3, Stra8, Scp3, GFRα1, CD90, VASA, Nanos2, KIT, and PLZF (P < 0.05), whereas the expression of Bad, cytochrome-c, and pro-Caspase 9 increased significantly (P < 0.05). We further examined the PI3K/AKT/mTOR pathway and found that the phosphorylation of PI3K, AKT, mTORC1, and S6K was significantly decreased by NP at all concentrations compared to that in untreated SSCs (P < 0.05). NP exerted the greatest effect at 30 μmol among all NP concentrations.

CONCLUSION

NP attenuated the proliferation, differentiation and stemness maintenance of SSCs while promoting apoptosis and oxidative stress. The associated mechanism may be related to the PI3K/AKT/mTOR pathway.

Autophagy Induced by ROS Aggravates Testis Oxidative Damage in Diabetes via Breaking the Feedforward Loop Linking p62 and Nrf2

Testicular dysfunction due to hyperglycemia is the main cause of infertility in diabetic men. Over the years, in order to solve this growing problem, a lot of research has been done and a variety of treatments have been created, but so far, there is no safe, effective, and practical method to prevent male infertility caused by diabetes. In this review, we emphasize the male infertility mechanism caused by diabetes from the effects of oxidative stress and autophagy on the function of testes via the PI3K/Akt/mTOR signaling pathway, and we highlight that oxidative stress-induced autophagy breaks the feedforward loop linking Nrf2 and p62 and promotes oxidative damage in diabetic testes.

Influence of nonylphenol from multilayer plastic films on artificial insemination of sows

Artificial insemination is common practice in mass livestock farming. Recently, it was shown that chemicals leaching from multilayer plastic bags affect the fertility of boars, although common quality tests did not show any impact on the sperm. It is not clear whether this incidence was a single case or whether it could be a systematic problem. Therefore, we studied six multilayer plastic bags. A total of 49 compounds were found, but most of them were at very low intensity. Nonylphenols in the range of 19-99 μg/g plastic were found. Migration tests using water and 10% ethanol as simulants, to mimic the behavior of semen with the extender, were performed. The most interesting migrants in terms of potential reprotoxicity were identified as nonylphenols. The identification in depth demonstrated the presence of 10 isomers of nonylphenol with a total concentration range between 16 to 58 μg/Kg simulant, among other migrants at lower concentration. The influence of these nonylphenols and their maximum tolerable concentration in direct contact with semen from boars was studied. Motility, viability, mitochondrial activity and acrosomes reacted were significantly affected at 10 mg/Kg of nonylphenols in contact with the sperm, but in vitro penetration rate was significantly decreased with only 2 mg/Kg. Insight into the mode of action is also provided.

Tebuconazole and Econazole Act Synergistically in Mediating Mitochondrial Stress, Energy Imbalance, and Sequential Activation of Autophagy and Apoptosis in Mouse Sertoli TM4 Cells: Possible Role of AMPK/ULK1 Axis

Tebuconazole and Econazole are triazole and imidazole fungicides currently used worldwide. Although their reproductive toxicity in mammals has been described, their effect on male reproductive systems has been poorly investigated. As humans may be exposed to different azole compounds simultaneously, the combinational in vitro toxicity of Tebuconazole and Econazole (MIX) in mouse Sertoli TM4 cells was investigated. This study demonstrates that Tebuconazole (40 µM) and Econazole (20 µM) act synergistically in mediating decrease of mitochondrial membrane potential (ΔΨm) and changes in mitochondrial morphology. These events were associated with ATP depletion, cell cycle arrest, and sequential activation of autophagy and apoptosis. Remarkable differences on other parameters such as AMP/ATP ratio and adenylate energy charge were observed. Pharmacological inhibition of autophagy by bafilomycin A1 leads to enhanced MIX-induced apoptosis suggesting an adaptive cytoprotective function for MIX-modulated autophagy. Finally, a possible role of AMPK/ULK1 axis in mediating adaptive signalling cascades in response to energy stress was hypothesized. Consistently, ULK1 Ser 555 phosphorylation occurred in response to AMPK (Thr 172) activation. In conclusion, Tebuconazole and Econazole combination, at concentrations relevant for dermal and clinical exposure, induces a severe mitochondrial stress in SCs. Consequently, a prolonged exposure may affect the ability of the cells to re-establish homeostasis and trigger apoptosis.

Irinotecan Induces Autophagy-Dependent Apoptosis and Positively Regulates ROS-Related JNK- and P38-MAPK Pathways in Gastric Cancer Cells

Background

Irinotecan (IRI) is considered an option for second-line treatment of advanced gastric cancer; however, acquired drug resistance currently limits its clinical application. Recently, many researchers have shown that autophagy plays a crucial role in the resistance of tumor cells to chemotherapy and radiotherapy. In this study, we investigated the relationship between autophagy and antitumor activity of IRI in gastric cancer cells.

Methods

We used MTT assay, flow cytometry and immunofluorescence staining to detect viability, apoptosis and autophagy in gastric cancer. Western blotting assay was used to determine the expression of LC3, Beclin-1, P62, cleaved PARP and Caspase 3. In vivo animal study was performed finally.

Results

We found that IRI treatment dose- and time-dependently inhibited growth and induced apoptosis in gastric cancer cells. Moreover, IRI treatment caused autophagy in these cells, whereas autophagy inhibitors—3-methyladenine (3-MA), chloroquine (CQ), and Beclin-1 small interfering RNA (siRNA)—suppressed cytotoxicity of IRI. A mechanistic analysis showed that IRI-induced autophagy and apoptosis were related to increased reactive oxygen species (ROS) accumulation and activation of the JNK- and p38-MAPK pathways. Further in vivo experiments revealed that IRI suppressed tumor growth, induced autophagy, and stimulated the JNK- and p38-MAPK pathways, whereas 3-MA attenuated these effects.

Conclusion

Taken together, these results indicate that IRI stimulates the ROS-related JNK- and p38-MAPK pathways to promote autophagy-dependent apoptosis. Thus, a combination of IRI with a pharmacological autophagy enhancer may be a promising therapeutic strategy against gastric cancer.

4-Hexylresorcinol Exhibits Different Characteristics to Estrogen

4-Hexylresorcinol (4HR) has been used as a food additive and antiseptic. The aim of this study was to evaluate whether the application of 4HR in breast cancer cells and ovariectomized rats showed estrogen-like effects. MCF-7 and SK-BR-3 cells were treated by solvent, 1–100 µM bisphenol-A (BPA), or 1–100 µM 4HR, respectively. 3-(4, 5-Dimethylthiazole-2-yl)- 2,5-diphenyltetrazolium bromide (MTT) assay and Western blot for extracellular signal-regulated kinase-1/-2 (ERK1/2), phosphorylated ERK1/2 (p-ERK1/2), estrogen receptor-α (ERα), and ERβ were done. As an in vivo study, ovariectomized rats (n = 15) received solvent, 125 mg/kg of 4HR, or 10 µg of 17-β estradiol via daily subcutaneous injection for 7 days. Blood samples were obtained for evaluation of prolactin levels. Pituitary glands and uteruses were biopsied for histological evaluation and Western blot analysis. Compared with the control group, the application of 4HR decreased the proliferation of MCF-7 and SK-BR-3 cells, while the application of BPA increased (p < 0.05). The application of BPA increased the expression of ERα, ERβ, and p-ERK1/2, but 4HR did not change the expression of ERα, ERβ, or p-ERK1/2 in MCF-7 cells. In an animal model, the 4HR group showed similar levels of ERα, ERβ, and prolactin expression in the pituitary gland compared to the solvent only group, while the estradiol group showed higher levels. Serum prolactin levels were similar between the 4HR and solvent only groups. Taken together, 1–100 µM 4HR did not show BPA-like behavior in MCF-7 cells, and 125 mg/kg of 4HR daily subcutaneous injection for 7 days did not demonstrate estradiol-like effects in ovariectomized rats. Collectively, 4HR has no estrogen-like effects on both ERα-positive cells and estrogen-deficient rat models.

Autophagy role in environmental pollutants exposure

During the last decades, the potential harmfulness derived from the exposure to environmental pollutants has been largely demonstrated, with associated damages ranging from geno- and cyto-toxicity to tissue malfunction and alterations in organism physiology. Autophagy is an evolutionarily-conserved cellular mechanism essential for cellular homeostasis, which contributes to protect cells from a wide variety of intracellular and extracellular stressors. Due to its pivotal importance, its correct functioning is directly linked to cell, tissue and organismal fitness. Environmental pollutants, particularly industrial compounds, are able to impact autophagic flux, either by increasing it as a protective response, by blocking it, or by switching its protective role toward a pro-cell death mechanism. Thus, the understanding of the effects of chemicals exposure on autophagy has become highly relevant, offering new potential approaches for risk assessment, protection and preventive measures to counteract the detrimental effects of environmental pollutants on human health.