The Keap1/Nrf2-ARE signaling pathway is involved in atrazine induced dopaminergic neurons degeneration via microglia activation

Atrazine's effects on mammalian physiology

Atrazine is a chlorotriazine herbicide that is one of the most widely used herbicides in the USA and the world. For over 60 years atrazine has been used on major crops including corn, sorghum, and sugarcane to control broadleaf and grassy weed emergence and growth. Atrazine has exerted a major economic and environmental impact over that time, resulting in reduced production costs and increased conservation tillage practices. However, widespread use and a long half-life led to a high prevalence of atrazine in the environment. Indeed, atrazine is the most frequent herbicide contaminant detected in water sources in the USA. Due to its almost ubiquitous presence and questions regarding its safety, atrazine has been well-studied. First reported to affect reproduction with potential disruptive effects which were later linked to the immune system, cancer, stress response, neurological disorders, and cardiovascular ailments in experimental models. Atrazine impact on multiple interwoven systems broadens the significance of atrazine exposure. The endeavor to uncover the mechanisms underlying atrazine-induced dysfunction in mammals is ongoing, with new genetic and pharmacological targets being reported. This review aims to summarize the prominent effects of atrazine on mammalian physiology, primarily focusing on empirical studies conducted in lab animal models and establish correlations with epidemiological human studies when relevant. In addition, current common patterns of toxicity and potential underlying mechanisms of atrazine action will be examined.

Unraveling the role of Nrf2 in dopaminergic neurons: a review of oxidative stress and mitochondrial dysfunction in Parkinson's disease

Nuclear factor erythroid 2-related factor 2 (Nrf2) is an essential transcriptional factor, involved in the regulation of countenance of various anti-oxidant enzymes and cytoprotective genes that respond to mitochondrial dysfunctions, oxidative stress, and neuroinflammation, thus potentially contributing to several neurodegenerative diseases (NDDs), including Parkison's disease (PD). PD is the second most prevalent progressive NDD, characterized by gradual neuronal death in substantia nigra pars compacta (SNpc), depletion of dopamine level, and a wide range of motor symptoms, including bradykinesia, tremor, tingling, and muscle fatigue. The etiopathology of PD is caused by multifactorial intertwined with the onset and progression of the disease. In this context, Nrf2 exhibits neuroprotective action by preserving dopaminergic neurons in the striatum and retarding the disease progression; thus, Nrf2 activation plays a crucial role in PD. Additionally, Nrf2 binds with the antioxidant response element, which is located in the promoter region of most of the genes that are responsible for coding antioxidant enzymes. Moreover, protein kinase C (PKC) mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3-kinase (PI3K) are also involved in the regulation of Keap1 pathway-mediated Nrf2 activation. As Nrf2 revealed its defensive and protective role in the central nervous system (CNS), it is gaining enough interest in treating PD. The treatments that are currently available are intended to alleviate the symptoms of PD; however, they are unable to halt the progression and severity of the disease. Therefore, in this review we delve deeper into various molecular mechanisms associated with oxidative stress, mitochondrial dysfunction, and neuroinflammation in PD. Additionally, we elaborated on the substantial role that NRF2 plays in mitigating these adverse effects and its potential as a therapeutic target.

A New Insight into the Mechanism of Atrazine-Induced Neurotoxicity: Triggering Neural Stem Cell Senescence by Activating the Integrated Stress Response Pathway

Atrazine (AT), a widely utilized chemical herbicide, causes widespread contamination of agricultural water bodies. Recently, exposure to AT has been linked to the development of age-related neurodegenerative diseases (NDs), suggesting its neurotoxicity potential. As an endocrine disruptor, AT targets the hypothalamus, a crucial part of the neuroendocrine system. However, the toxicological mechanism of AT exposure to the hypothalamus and its correlation with ND development remain unexplored. Our results indicated that AT exposure caused significant morphological and structural damage to the hypothalamus, leading to the loss of mature and intact neurons and microglial activation. Furthermore, hypothalamic neural stem cells (HtNSCs) were recruited to areas of neuronal damage caused by AT. Through in vivo and in vitro experiments, we clarified the outcomes of AT-induced HtNSC recruitment alongside the loss of mature/intact neurons. Mechanistically, AT induces senescence in these recruited HtNSCs by activating integrated stress response signaling. This consequently hinders the repair of damaged neurons by inhibiting HtNSC proliferation and differentiation. Overall, our findings underscore the pivotal role of the integrated stress response pathway in AT-induced HtNSC senescence and hypothalamic damage. Additionally, the present study offers novel perspectives to understand the mechanisms of AT-induced neurotoxicity and provides preliminary evidence linking AT contamination to the development of NDs.

Lycopene mitigates atrazine-induced hypothalamic neural stem cell senescence by modulating the integrated stress response pathway

BACKGROUND

Atrazine, a widely used herbicide, has become a major pollutant in agricultural water bodies. Pesticide contamination, including atrazine, is linked to a high incidence of age-related neurodegenerative diseases, suggesting its neurotoxic potential. Lycopene, a potent antioxidant, is renowned for its diverse pharmacological effects, especially its neuroprotective properties. However, the underlying pharmacological mechanisms of lycopene and its impact on potential pathways against atrazine-induced hypothalamic damage have not been elucidated.

PURPOSE

Our study aimed to elucidate how lycopene ameliorates hypothalamic injury triggered by atrazine exposure, with a special focus on the pluripotency of neural stem cells (NSCs) and pathways involved in cell senescence.

METHODS

Mice were administered lycopene and/or atrazine via gavage for 21 days. The C17.2 NSC cell line and specific molecular inhibitors were utilized to examine the potential protective effects of lycopene in vitro. Morphological changes and ultrastructural damage in the hypothalamus were observed by hematoxylin-eosin staining and transmission electron microscopy, respectively. The mechanisms of action of lycopene were explored through various methods, including senescence β-galactosidase staining, multiplex immunofluorescence, Western blotting and qRT‒PCR.

RESULTS

Our results indicated that lycopene notably ameliorated atrazine-induced histological and ultrastructural damage, as well as the loss of intact and mature neurons in mouse hypothalami. Additionally, hypothalamic NSCs (HtNSCs) and microglia were recruited to areas of neuronal injury after atrazine exposure; intriguingly, lycopene treatment reduced this recruitment. Through in vivo and in vitro assays, we elucidated the outcomes of atrazine-induced HtNSC recruitment and neuronal loss, along with the neuroprotective mechanisms of lycopene. Mechanistically, lycopene prevents atrazine-induced senescence in HtNSCs and enhances their proliferation and differentiation by inhibiting the integrated stress response (ISR) signaling pathway, thus promoting the renewal of damaged neurons in the hypothalamus.

CONCLUSIONS

Collectively, the results of the present study reveal, for the first time, that lycopene mitigates atrazine-induced HtNSC senescence by modulating the ISR signaling pathway. These findings offer novel insights into the role of lycopene in preventing and alleviating NSC senescence and suggest its potential development as a new therapy for neurodegenerative diseases.

A review of the potential adverse health impacts of atrazine in humans

Atrazine is a widely used chlorinated triazine herbicide in agricultural settings, which has raised concerns over its potential adverse effects on human health. The extensive application of atrazine has resulted in its pervasive presence in the environment, contaminating soil, groundwater, and surface water. While earlier research suggested that atrazine is unlikely to pose a health concern, recent evidence has indicated the necessity to reassess this point of view. This review aims to assess the recent evidence on atrazine's adverse effects on human health, focusing on (i) Cancer, (ii) Metabolic Diseases, (iii) Reproductive System, (iv) Neural System, and (v) Epigenetic Effects. Strategies to mitigate atrazine contamination and limitations of previous studies are also discussed. We strongly believe that further investigation is necessary to determine the potential detrimental consequences of atrazine in humans, particularly in developing countries, where herbicides are widely used without stringent safety regulations. Therefore, the current review will be beneficial for guiding future research and regulatory measures concerning the use of atrazine.

The role of miR-216a-mediated Nrf2 pathway in muscle oxidative stress of Siniperca chuatsi induced by cadmium

Cadmium (Cd) is a toxic heavy metal pollutant in the environment. Excessive Cd in water has toxic effects on fish, endangering their healthy growth and ultimately affecting the quality and safety of aquatic products. To evaluate the toxicity of excessive Cd to fish through potential oxidative damage, Siniperca chuatsi was exposed to Cd in water for 15 days. It was found that Cd exposure significantly decreased the survival rate of S. chuatsi and Cd was detected in their muscle. Meanwhile, Cd disrupts the redox balance by reducing antioxidant enzyme activities, increasing reactive oxygen species (ROS) and malondialdehyde (MDA) levels in muscle, and promoting oxidative damage. Histomorphology showed that enlargement of muscle fiber gaps, cell swelling and vacuolar degeneration after Cd exposure. In addition, Cd toxicity induced up-regulating the expression of miR-216a, while down-regulation of Nrf2 protein and its downstream antioxidant enzyme genes expression. Further analysis revealed that miR-216a was significantly negatively correlated with the expression of Nrf2, and injection of miR-216a antagomir significantly enhanced the expression of Nrf2 and antioxidant enzyme genes, as well as the activity of antioxidant enzymes, thereby reducing the damage of Cd to fish. These results suggested that miR-216a-mediated Nrf2 signaling pathway plays an important role in Cd-induced oxidative stress of S. chuatsi muscle.

Endocrine toxicity of atrazine and its underlying mechanisms

Atrazine (ATR) is one of the most widely utilized herbicides globally and is prevalent in the environment due to its extensive use and long half-life. It can infiltrate the human body through drinking water, ingestion, and dermal contact, and has been recognized as an environmental endocrine disruptor. This study aims to comprehensively outline the detrimental impacts of ATR on the endocrine system. Previous research indicates that ATR is harmful to various bodily systems, including the reproductive system, nervous system, adrenal glands, and thyroi d gland. The toxic effects of ATR on the endocrine system and its underlying molecular mechanisms are summarized as follows: influencing the expression of kisspeptin in the HPG axis, consequently affecting steroid synthesis; disrupting DNA synthesis and meiosis, as well as modifying DNA methylation levels, leading to reproductive and developmental toxicity; impacting dopamine by altering Nurr1, VMAT2, and DAT expression, consequently affecting dopamine synthesis and transporter expression, and influencing other neurotransmitters, resulting in neurotoxicity; and changing adipose tissue synthesis and metabolism by reducing basal metabolism, impairing cellular oxidative phosphorylation, and inducing insulin resistance. Additionally, a compilation of natural products used to mitigate the toxic effects of ATR has been provided, encompassing melatonin, curcumin, quercetin, lycopene, flavonoids, vitamin C, vitamin E, and other natural remedies. It is important to note that existing research predominantly relies on in vitro and ex vivo experiments, with limited population-based empirical evidence available.

Protective Effect and Related Mechanism of Modified Danggui Buxue Decoction on Retinal Oxidative Damage in Mice based on Network Pharmacology

INTRODUCTION

Age-related macular degeneration (AMD) is one of the common diseases that cause vision loss in the elderly, and oxidative stress has been considered a major pathogenic factor for AMD. Modified Danggui Buxue Decoction (RRP) has a good therapeutic effect on non-proliferatic diabetic retinopathy and can improve the clinical symptoms of patients.

METHODS

The key ingredients and core targets of RRP protecting retinal oxidative damage were obtained by Network pharmacology analysis. A mouse retinal oxidative damage model induced by tail vein injection of 1% NaIO3 solution (25 mg/kg) was treated with RRP for 4 weeks and used to verify the pharmacodynamics and related mechanism.

AIM

This study aimed to predict and verify the protective effect and mechanism of RRP on retinal oxidative damage in mice based on network pharmacology and animal experiments.

RESULTS

A total of 15 key active components included in RRP interacted with 57 core targets related to retinal oxidative damage (such as AKT1, NFE2L2, HMOX1), mainly involved in the AGE-RAGE signaling pathway in diabetic complications, PI3K-AKT signaling pathway and so on. Further studies in vivo found that RRP improved the retinal oxidative damage, increased the content of SOD and GSH, decreased the content of MDA in mouse serum, promoted the expression of p-PI3K, p-AKT, Nrf2, HO-1 and NQO1 proteins in the mouse retina, and inhibited the expression of Nrf2 in the cytoplasm.

CONCLUSION

This study revealed that RRP had a protective effect on oxidative damage of the retina in mice, and might exert anti-oxidative effect by activating the PI3K/Akt/Nrf2 signal pathway. This study provided scientific data for the further development of hospital preparations of RRP, and a good theoretical basis for the clinical application of RRP.

Exploring the multifaceted role of NRF2 in brain physiology and cancer: A comprehensive review

Chronic oxidative stress plays a critical role in the development of brain malignancies due to the high rate of brain oxygen utilization and concomitant production of reactive oxygen species. The nuclear factor-erythroid-2-related factor 2 (NRF2), a master regulator of antioxidant signaling, is a key factor in regulating brain physiology and the development of age-related neurodegenerative diseases. Also, NRF2 is known to exert a protective antioxidant effect against the onset of oxidative stress-induced diseases, including cancer, along with its pro-oncogenic activities through regulating various signaling pathways and downstream target genes. In glioblastoma (GB), grade 4 glioma, tumor resistance, and recurrence are caused by the glioblastoma stem cell population constituting a small bulk of the tumor core. The persistence and self-renewal capacity of these cell populations is enhanced by NRF2 expression in GB tissues. This review outlines NRF2's dual involvement in cancer and highlights its regulatory role in human brain physiology and diseases, in addition to the development of primary brain tumors and therapeutic potential, with a focus on GB.

Vitamin E-Inhibited Phoxim-Induced Renal Oxidative Stress and Mitochondrial Apoptosis In Vivo and In Vitro of Piglets

Exposure to phoxim at low levels caused bioaccumulation with neurotoxicity but also induced oxidative stress, tissue damage, and abnormal nutrient metabolism. This study described that vitamin E ameliorates phoxim-induced nephrotoxicity via inhibiting mitochondrial apoptosis. In vivo, 24 healthy piglets were treated with phoxim (0 mg/kg and 500 mg/kg) and vitamin E + phoxim (vitamin E + phoxim: 200 mg/kg + 500 mg/kg). In vitro, PK15 cells were treated with phoxim (0 mg/L and 1 mg/L) and vitamin E + phoxim (phoxim + vitamin E: 1 mg/L + 1 mg/L) for 12 h and 24 h. Our results indicated that accumulation of ROS, oxidative stress, and renal cell injury through stimulation of mitochondrial apoptosis resulted in phoxim-induced nephrotoxicity. Phoxim resulted in swollen mitochondria, blurred internal cristae, renal glomerular atrophy, and renal interstitial fibrosis. Vitamin E alleviated the adverse effects of phoxim by reducing ROS and improving antioxidant capacity in vivo and in vitro. Vitamin E significantly increased SDH in vitro (p < 0.01), while it decreased ROS, Bad, and cyto-c in vitro and SOD and CAT in vivo (p < 0.05). Vitamin E ameliorated phoxim-induced renal histopathologic changes, and mitochondria swelled. In addition, vitamin E regulates phoxim-induced apoptosis by alleviating oxidative damage to the mitochondria.

Pesticides at brain borders: Impact on the blood-brain barrier, neuroinflammation, and neurological risk trajectories

Pesticides are omnipresent, and they pose significant environmental and health risks. Translational studies indicate that acute exposure to high pesticide levels is detrimental, and prolonged contact with low concentrations of pesticides, as single and cocktail, could represent a risk factor for multi-organ pathophysiology, including the brain. Within this research template, we focus on pesticides' impact on the blood-brain barrier (BBB) and neuroinflammation, physical and immunological borders for the homeostatic control of the central nervous system (CNS) neuronal networks. We examine the evidence supporting a link between pre- and postnatal pesticide exposure, neuroinflammatory responses, and time-depend vulnerability footprints in the brain. Because of the pathological influence of BBB damage and inflammation on neuronal transmission from early development, varying exposures to pesticides could represent a danger, perhaps accelerating adverse neurological trajectories during aging. Refining our understanding of how pesticides influence brain barriers and borders could enable the implementation of pesticide-specific regulatory measures directly relevant to environmental neuroethics, the exposome, and one-health frameworks.

Atrazine induces phagocytotic dysfunction of microglia depends on nucleocytoplasmic translocation of acetylated HMGB1

Atrazine (ATR) is a widely applied herbicide which was named an environmental endocrine disrupting chemical (EDC). Increasing evidence indicates ATR causes neurotoxic effects resulting in central nervous system (CNS) disease. As the primary immunocytes in the CNS, microglia cells carry out their phagocytosis to maintain the CNS microenvironment by preventing damage from healthy cells. However, the mechanism in which ATR affects the phagocytic function of microglia remains unclear. The present study was designed to investigate the effect of ATR on the phagocytosis of microglia. BV-2 cells and primary microglia selected as microglial models in which BV-2 cells were administrated by ATR at different concentrations (0, 4, 8, 16 μM) for 24 h. Results demonstrated ATR dose-dependently increased the expression of ionized calcium binding adapter molecule 1 (Iba-1), indicating that microglia were activated. Microglial phagocytotic activity induced by ATR fluctuated at the different time points, accompanied by fluctuations in membrane receptor MERTK and cytoplasmic lysosomal marker LAMP1 (two markers related to cell phagocytosis). In this period, the expression of iNOS gradually increased. A mechanistic study further demonstrated that the translocation of High Mobility Group Protein-B1 (HMGB1) from nucleus to cytoplasm in the BV-2 and primary microglial cells induced by ATR, and the process showed a positive correlation with phagocytosis activity of BV-2 cells induced by ATR (r = 0.8030, P = 0.05; α = 0.1). ATR was also shown to spur the acetylation of HMGB1 by breaking the balance between acetylase P300 and deacetylase SIRT1. Unexpectedly, the inhibition of acetylating HMGB1 by resveratrol (Res) was effectively retained by HMGB1 in the nucleus, reversed the SIRT1 and MERTK expression, and enhanced the phagocytosis activity in BV-2 cells. Our results suggested that ATR exposure influenced microglial phagocytosis by acetylating HMGB1 further translocated it in the nucleoplasm.

Chronic Exposure to Vinclozolin Induced Fibrosis, Mitochondrial Dysfunction, Oxidative Stress, and Apoptosis in Mice Kidney

Vinclozolin is one of the most used fungicides in the control of fungi in fruits, vegetables, and ornamental plants. The effects of its exposure on different organs have been described, but information regarding its relevance to vinclozolin-induced nephrotoxicity is largely missing. This study focuses on the potential mechanism of vinclozolin-induced nephrotoxicity. CD1 male mice were administered vinclozolin (100 mg/kg) by oral gavage for 28 days. Vinclozolin administration decreased body weight over the treatment period and at the end of the experiment, increased the ratio of kidney weight to body weight and increased serum urea nitrogen and creatinine contents. Vinclozolin also induced histopathological alterations, including tubular dilatation and necrosis and impaired the integrity of the renal-tubular architecture and kidney fibrosis. The analyses conducted showed that vinclozolin administration altered the mRNA levels of mitochondrial function-related proteins (SIRT3, SIRT1, PGC-1α, TFAM, NRF1, VDAC-1, and Cyt c) and oxidative stress (increased lipid peroxidation and decreased total antioxidative capacity, catalase, and superoxide dismutase activities, glutathione levels, and glutathione peroxidase activity) in the kidneys. Furthermore, vinclozolin induced toxicity that altered Nrf2 signalling and the related proteins (HO-1 and NQO-1). Vinclozolin administration also affected both the extrinsic and intrinsic apoptotic pathways, upregulating the expression of proapoptotic factors (Bax, Caspase 3, and FasL) and downregulating antiapoptotic factor (Bcl-2) levels. This study suggests that vinclozolin induced nephrotoxicity by disrupting the transcription of mitochondrial function-related factors, the Nrf2 signalling pathway, and the extrinsic and intrinsic apoptotic pathways.

Toxic Exposure to Endocrine Disruptors Worsens Parkinson's Disease Progression through NRF2/HO-1 Alteration

Human exposure to endocrine disruptors (EDs) has attracted considerable attention in recent years. Different studies showed that ED exposure may exacerbate the deterioration of the nervous system's dopaminergic capacity and cerebral inflammation, suggesting a promotion of neurodegeneration. In that regard, the aim of this research was to investigate the impact of ED exposure on the neuroinflammation and oxidative stress in an experimental model of Parkinson's disease (PD). PD was induced by intraperitoneally injections of MPTP for a total dose of 80 mg/kg for each mouse. Mice were orally exposed to EDs, starting 24 h after the first MPTP administration and continuing through seven additional days. Our results showed that ED exposure raised the loss of TH and DAT induced by the administration of MPTP, as well as increased aggregation of α-synuclein, a key marker of PD. Additionally, oral exposure to EDs induced astrocytes and microglia activation that, in turn, exacerbates oxidative stress, perturbs the Nrf2 signaling pathway and activates the cascade of MAPKs. Finally, we performed behavioral tests to demonstrate that the alterations in the dopaminergic system also reflected behavioral and cognitive alterations. Importantly, these changes are more significant after exposure to atrazine compared to other EDs. The results from our study provide evidence that exposure to EDs may play a role in the development of PD; therefore, exposure to EDs should be limited.