Activation of the p62-Keap1-Nrf2 pathway protects against oxidative stress and excessive autophagy in ovarian granulosa cells to attenuate DEHP-induced ovarian impairment in mice

Regulatory Mechanism of Autophagy in Premature Ovarian Failure

Premature ovarian failure (POF) is intricately linked to cellular fates such as senescence, apoptosis, and impaired granulosa cell (GC) differentiation, each of which contributes to ovarian dysfunction and follicular depletion. Autophagy is essential in preventing POF by maintaining cellular homeostasis through the degradation and recycling of damaged organelles and proteins, thereby preserving ovarian function and preventing follicular depletion. Recent studies have revealed that the targeted regulation and disruption of autophagy through various molecular mechanisms ultimately lead to the pathogenesis of POF. In this review, we provide a comprehensive analysis of the disruption in regulatory mechanisms of autophagy contributing to POF. Specifically, we elucidate the molecular mechanisms that can be targeted to restore autophagy homeostasis, offering therapeutic potential for the treatment of POF.

Human umbilical cord mesenchymal stem cells alleviate chemotherapy-induced premature ovarian insufficiency mouse model by suppressing ferritinophagy-mediated ferroptosis in granulosa cells

Primary ovarian insufficiency (POI) in younger women (under 40) manifests as irregular periods, high follicle-stimulating hormone (FSH), and low estradiol (E2), often triggered by chemotherapy. Though mesenchymal stem cell (MSC) therapy shows promise in treating POI, its exact mechanism remains unclear. This study reveals that human umbilical cord-derived MSCs (hUC-MSCs) can protect ovarian granulosa cells (GCs) from cyclophosphamide (CTX)-induced ferroptosis, a form of cell death driven by iron accumulation. CTX, commonly used to induce POI animal model, triggered ferroptosis in GCs, while hUC-MSCs treatment mitigated this effect, both in vivo and in vitro. Further investigations using ferroptosis and autophagy inhibitors suggest that hUC-MSCs act by suppressing ferroptosis in GCs. Interestingly, hUC-MSCs activate a protective antioxidant pathway in GCs via NRF2, a stress-response regulator. Overall, our findings suggest that hUC-MSCs improve ovarian function in CTX-induced POI by reducing ferroptosis in GCs. This study not only clarifies the mechanism behind the benefits of hUC-MSCs but also strengthens the case for their clinical use in treating POI. Additionally, it opens up a new avenue for protecting ovaries from chemotherapy-induced damage by regulating ferroptosis.

Paeoniflorin Promotes Ovarian Development in Mice by Activating Mitophagy and Preventing Oxidative Stress

During the development of animal organs, various adverse stimuli or toxic environments can induce oxidative stress and delay ovarian development. Paeoniflorin (PF), the main active ingredient of the traditional Chinese herb Paeonia lactiflora Pall., has protective effects on various diseases by preventing oxidative stress. However, the mechanism by which PF attenuates oxidative damage in mouse ovaries remains unclear. We evaluated the protective effects of PF on ovaries in an H2O2-induced mouse oxidative stress model. The H2O2-induced mouse ovarian oxidative stress model was used to explore the protective effect of PF on ovarian development. Histology and follicular development were observed. We then detected related indicators of cell apoptosis, oxidative stress, and autophagy in mouse ovaries. We found that PF inhibited H2O2-induced ovarian cell apoptosis and ferroptosis and promoted granulosa cell proliferation. PF prevented oxidative stress by increasing nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expression levels. In addition, the autophagic flux of ovarian cells was activated and was accompanied by increased lysosomal biogenesis. Moreover, PF-mediated autophagy was involved in clearing mitochondria damaged by H2O2. Importantly, PF administration significantly increased the number of primordial follicles, primary follicles, secondary follicles, and antral follicles. PF administration improved ovarian sizes compared with the H2O2 group. The present study suggested that PF administration reversed H2O2-induced ovarian developmental delay and promoted follicle development. PF-activated mitophagy is crucial for preventing oxidative stress and improving mitochondrial quality.

Bioactive Compounds Protect Mammalian Reproductive Cells from Xenobiotics and Heat Stress-Induced Oxidative Distress via Nrf2 Signaling Activation: A Narrative Review

Oxidative stress occurs when there is an imbalance between the production of reactive oxygen species (ROS) and the body's antioxidant defenses. It poses a significant threat to the physiological function of reproductive cells. Factors such as xenobiotics and heat can worsen this stress, leading to cellular damage and apoptosis, ultimately decreasing reproductive efficiency. The nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway plays a crucial role in defending against oxidative stress and protecting reproductive cells via enhancing antioxidant responses. Dysregulation of Nrf2 signaling has been associated with infertility and suboptimal reproductive performance in mammals. Recent advancements in therapeutic interventions have underscored the critical role of Nrf2 in mitigating oxidative damage and restoring the functional integrity of reproductive cells. In this narrative review, we delineate the harmful effects of heat and xenobiotic-induced oxidative stress on reproductive cells and explain how Nrf2 signaling provides protection against these challenges. Recent studies have shown that activating the Nrf2 signaling pathway using various bioactive compounds can ameliorate heat stress and xenobiotic-induced oxidative distress and apoptosis in mammalian reproductive cells. By comprehensively analyzing the existing literature, we propose Nrf2 as a key therapeutic target for mitigating oxidative damage and apoptosis in reproductive cells caused by exposure to xenobiotic exposure and heat stress. Additionally, based on the synthesis of these findings, we discuss the potential of therapies focused on the Nrf2 signaling pathway to improve mammalian reproductive efficiency.

A novel perspective on di-hexyl phthalate (2-ethylhexyl)-induced reproductive toxicity in females: Lipopolysaccharide synergizes with mono-2-ethylhexyl ester to cause inflammatory apoptosis rather than autophagy in ovarian granulosa cells

Di-hexyl phthalate (2-ethylhexyl) (DEHP) has been confirmed to cause female reproductive toxicity in humans and model animals by affecting the survival of ovarian granulosa cells (GCs), but the interrelationships between DEHP's on autophagy, apoptosis, and inflammation in GCs are not clear. Our previous study demonstrated that DEHP exposure resulted in the disturbance of intestinal flora associated with serum LPS release, which in turn led to impaired ovarian function. LPS has also been shown to determine cell fate by modulating cellular autophagy, apoptosis, and inflammation. Therefore, this study investigated the role and link between LPS and autophagy, apoptosis, and inflammation of GCs in DEHP-induced ovarian injury. Here, we constructed an in vivo injury model by continuous gavage of 0-1500 mg/kg of DEHP in female mice for 30 days and an in vitro injury model by treatment of human ovarian granulosa cells (KGN) cells with mono-2- ethylhexyl ester (MEHP, an active metabolite of DEHP in vivo). In addition, the expression of relevant pathway molecules was detected by immunohistochemistry, immunofluorescence, qRT-PCR, and Western blotting after the addition of the autophagy inhibitor 3-methyladenine (3-MA), the apoptosis inhibitor Z-VAD- FMK and the NF-κB inhibitor BAY11-7082. The current study found that autophagy and apoptosis were significantly activated in GCs of DEHP-induced atretic follicles in vivo and found that MEHP-induced KGN cells autophagy and apoptosis were independent and potentially cytotoxic of each other in vitro. Further studies confirmed that DEHP exposure resulted in LPS release from the intestinal tract and entering the ovary, thereby participating in DEHP-induced inflammation of GCs. In addition, we found that exogenous LPS synergized with MEHP could activate the NF-κB signaling pathway to induce inflammation and apoptosis of GCs in a relatively prolonged exposure condition. Meanwhile, inhibition of inflammatory activation could rescue apoptosis and estrogen secretion function of GCs induced by MEHP combined with LPS. These results indicated that the increased LPS influenced by DEHP might cooperate with MEHP to induce inflammatory apoptosis of GCs, an important cause of ovarian injury in mice.

Melatonin ameliorates 10-hydroxycamptothecin-induced oxidative stress and apoptosis via autophagy-regulated p62/Keap1/Nrf2 pathway in mouse testicular cells

10-Hydroxycamptothecin (HCPT) is a widely used clinical anticancer drug but has a significant side effect profile. Melatonin has a beneficial impact on the chemotherapy of different cancer cells and reproductive processes, but the effect and underlying molecular mechanism of melatonin's involvement in the HCPT-induced side effects in cells, especially in the testicular cells, are poorly understood. In this study, we found that melatonin therapy significantly restored HCPT-induced testicular cell damage and did not affect the antitumor effect of HCPT. Further analysis found that melatonin therapy suppressed HCPT-induced DNA damage associated with ataxia-telangiectasia mutated- and Rad3-related and CHK1 phosphorylation levels in the testis. Changes in apoptosis-associated protein levels (Bax, Bcl-2, p53, and Cleaved caspase-3) and in reactive oxygen species-associated proteins (Nrf2 and Keap1) and index (malondialdehyde and glutathione) suggested that melatonin treatment relieved HCPT-induced cell apoptosis and oxidative damage, respectively. Mechanistically, melatonin-activated autophagy proteins (ATG7, Beclin1, and LC3bII/I) may induce p62-dependent autophagy to degrade Keap1, eliciting Nrf2 from Keap1-Nrf2 interaction to promote antioxidant enzyme expression such as HO-1, which would salvage HCPT-induced ROS production and mitochondrial dysfunction. Collectively, this study reveals that melatonin therapy may protect testicular cells from HCPT-induced damage via the activation of autophagy, which alleviates oxidative stress, mitochondrial dysfunction, and cell apoptosis.

Ca2+ homeostasis imbalance induced by Pparg: A key factor in di (2-ethylhexyl) phthalate (DEHP)-induced cardiac dysfunction in zebrafish larvae

Widespread application of the typical phthalate plasticizers, di (2-ethylhexyl) phthalate (DEHP), poses a serious potential threat to the health of animals and even humans. Previous studies have confirmed the mechanism of DEHP-induced cardiac developmental defects in zebrafish larvae. However, the mechanism of cardiac dysfunction is still unclear. Thus, this work aimed to comprehensively investigate the mechanisms involved in DEHP-induced cardiac dysfunction through computational simulations, in vivo assays in zebrafish, and in vitro assays in cardiomyocytes. Firstly, molecular docking and western blot initially investigated the activating effect of DEHP on Pparg in zebrafish. Although GW9662 (PPARG antagonist) effectively alleviated DEHP-induced cardiac dysfunction and lipid metabolism disorders, it did not restore significant decreases in mitochondrial membrane potential and ATP levels. In vitro assays in cardiomyocytes, DEHP caused overexpression of PPARG and proteins involved in the regulation of Ca2+ homeostasis, and the above abnormalities were effectively alleviated by GW9662, suggesting that the Ca2+ homeostatic imbalance caused by activation of PPARG by DEHP seems to be the main cause of DEHP-induced cardiac dysfunction. To sum up, this work not only refines the mechanism of toxic effects of cardiotoxicity induced by DEHP, but provides an important theoretical basis for enriching the toxicological effects of DEHP.

Mitochondrial dysfunction mediated by thioredoxin-interacting protein: A crucial determinant in di(2-ethylhexyl) phthalate-induced liver failure

Di(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer that can interfere with the endocrine system and cause liver damage. However, the molecular mechanism of DEHP-induced liver injury is unclear. This study aimed to investigate the effects of DEHP on liver function and its relationship with thioredoxin-interacting protein (TXNIP) and mitochondrial oxidative stress pathway. We used C57BL/6 J mice and THLE-2 liver cells as in vivo and in vitro models, respectively, and treated them with different doses of DEHP, and measured the relevant biochemical indicators and molecular markers. We found that DEHP significantly increased the expression of TXNIP and NLRP3, while decreasing the expression of mitochondrial functional proteins, such as PGC-1α, TFAM, NRF1, NDUHA9, SDHA, MFN1. This resulted in mitochondrial dysfunction, manifested by reduced ATP generation, increased inflammatory factor release, elevated liver enzyme indicators, decreased mitochondrial membrane potential and increased oxidative stress. We further demonstrated that TXNIP upregulation activated NF-κB and MAPK signaling pathways, such as NF-κB, IκB, TAB2, TRAF6, ERK1, JNK, p38 MAPK, MEK1, which exacerbated oxidative stress and inflammation, leading to liver damage. Additionally, we found that treatment with the antioxidant MitoQ partially alleviated DEHP-induced liver toxicity, while silencing TXNIP more effectively restored mitochondrial function. Our study supports the hypothesis that DEHP induces mitochondrial oxidative stress through the TXNIP signaling pathway, resulting in liver dysfunction in mice, and suggests possible links between endocrine-disrupting chemicals and human diseases.

Di (2-ethylhexyl) phthalate alters neurobehavioral responses and oxidative status, architecture, and GFAP and BDNF signaling in juvenile rat's brain: Protective role of Coenzyme10

Di-(2-ethylhexyl) phthalate (DEHP), a phthalate plasticizer, is widely spread in the environment, presenting hazards to human health and food safety. Hence, this study examined the probable preventive role of coenzyme10 (CQ10) (10 mg/kg.b.wt) against DEHP (500 mg/kg.wt) - induced neurotoxic and neurobehavioral impacts in juvenile (34 ± 1.01g and 3 weeks old) male Sprague Dawley rats in 35-days oral dosing trial. The results indicated that CQ10 significantly protected against DEHP-induced memory impairment, anxiety, depression, spatial learning disorders, and repetitive/stereotypic-like behavior. Besides, the DEHP-induced depletion in dopamine and gamma amino butyric acid levels was significantly restored by CQ10. Moreover, CQ10 significantly protected against the exhaustion of CAT, GPx, SOD, GSH, and GSH/GSSG ratio, as well as the increase in malondialdehyde, Caspas-3, interleukin-6, and tumor necrosis factor-alpha brain content accompanying with DEHP exposure. Furthermore, CQ10 significantly protected the brain from the DEHP-induced neurodegenerative alterations. Also, the increased immunoexpression of brain-derived neurotrophic factor, not glial fibrillary acidic protein, in the cerebral, hippocampal, and cerebellar brain tissues due to DEHP exposure was alleviated with CQ10. This study's findings provide conclusive evidence that CQ10 has the potential to be used as an efficient natural protective agent against the neurobehavioral and neurotoxic consequences of DEHP.