New Insights into the Nrf-2/HO-1 Signaling Axis and Its Application in Pediatric Respiratory Diseases

Activation of the Nrf2/Keap1 signaling pathway mediates the neuroprotective effect of Perillyl alcohol against cerebral hypoxic-ischemic damage in neonatal rats

Neonatal hypoxic-ischemic encephalopathy (HIE) is a severe disease with a poor prognosis, whose clinical treatment is still limited to therapeutic hypothermia with limited efficacy. Perillyl alcohol (POH), a natural monoterpene found in various plant essential oils, has shown neuroprotective properties, though its effects on HIE are not well understood. This study investigates the neuroprotective effects of POH on HIE both in vitro and in vivo. We established an in vitro model using glucose deprivation and hypoxia/reperfusion (OGD/R) in PC12 cells, alongside an in vivo model via the modified Rice-Vannucci method. Results indicated that POH acted as an indirect antioxidant, reducing inducible nitric oxide synthase and malondialdehyde production, maintaining content of antioxidant molecules and enzymes in OGD/R-induced PC12 cells. In vivo, POH remarkably lessened infarct volume, reduced cerebral edema, accelerated tissue regeneration, and blocked reactive astrogliosis after hypoxic-ischemic brain injury. POH exerted antiapoptotic activities through both the intrinsic and extrinsic apoptotic pathways. Mechanistically, POH activated Nrf2 and inactivated its negative regulator Keap1. The use of ML385, a Nrf2 inhibitor, reversed these effects. Overall, POH mitigates neuronal damage in HIE by combating oxidative stress, reducing inflammation, and inhibiting apoptosis via the Nrf2/Keap1 pathway, suggesting its potential for HIE treatment.

The mechanism of hypoxia-inducible factor-1α enhancing the transcriptional activity of transferrin ferroportin 1 and regulating the Nrf2/HO-1 pathway in ferroptosis after cerebral ischemic injury

Cerebral ischemic/reperfusion (I/R) injury has high disability and morbidity. Hypoxia-inducible factor-1α (HIF-1α) may enhance the transcriptional activity of transferrin ferroportin 1 (FPN1) in regulating ferroptosis after cerebral ischemia injury (CII). In this study, cerebral I/R injury rat models were established and treated with pcDNA3.1-HIF-1α, pcDNA3.1-NC lentiviral plasmid, or ML385 (a specific Nrf2 inhibitor). Additionally, oxygen-glucose deprivation/reoxygenation (OGD/R) exposed PC12 cells were used as an in vitro model of cerebral ischemia and treated with pcDNA3.1-HIF-1α, si-FPN1, or ML385. The results elicited that cerebral I/R injury rats exhibited increased Longa scores, TUNEL and NeuN co-positive cells, Fe2+ concentration, ROS and HIF-1α levels, and MDA content, while reduced cell density and number, GSH content, and GPX4 protein level. Morphologically abnormal and disordered hippocampal neurons were also observed in CII rats. HIF-1α inhibited brain neuron ferroptosis and ameliorated I/R injury. HIF-1α alleviated OGD-induced PC12 cell ferroptosis. OGD/R decreased FPN1 protein level in PC12 cells, and HIF-1α enhanced FPN1 transcriptional activity. FPN1 knockdown reversed HIF-1α-mediated alleviation of OGD/R-induced ferroptosis. HIF-1α activated the Nrf2/HO-1 pathway by enhancing FPN1 expression and alleviating OGD/R-induced ferroptosis. Conjointly, HIF-1α enhanced the transcriptional activity of FPN1, activated the Nrf2/HO-1 pathway, and inhibited ferroptosis of brain neurons, thereby improving I/R injury in CII rats.

Enhancement of keratinocyte survival and migration elicited by interleukin 24 upregulation in dermal microvascular endothelium upon welding-fume exposure

Occupational exposure to welding fumes constitutes a serious health concern. Although the effects of fumes on the respiratory tract have been investigated, few apparent reports were published on their effects on the skin. The purpose of this study was to investigate the effects of exposure to welding fumes on skin cells, focusing on interleukin-24 (IL-24), a cytokine involved in the pathophysiology of skin conditions, such as atopic dermatitis and psoriasis. Treatment with welding fumes increased IL-24 expression and production levels in human dermal microvascular endothelial cells (HDMEC) which were higher than that in normal human epidermal keratinocytes. IL-24 levels in Trolox and deferoxamine markedly suppressed welding fume-induced IL-24 expression in HDMEC, indicating that oxidative stress may be involved in this cytokine expression. IL-24 released from HDMEC protected keratinocytes from welding fume-induced damage and enhanced keratinocyte migration. Serum IL-24 was higher in welding workers than in general subjects and was positively correlated with elevated serum levels of 8-hydroxy-2'-deoxyguanosine, an oxidative stress marker. In summary, welding fumes enhanced IL-24 expression in HDMEC, stimulating keratinocyte survival and migration. IL-24 expression in endothelial cells may act as an adaptive response to welding-fume exposure in the skin.

Effects of Akt Activator SC79 on Human M0 Macrophage Phagocytosis and Cytokine Production

Akt is an important kinase in metabolism. Akt also phosphorylates and activates endothelial and neuronal nitric oxide (NO) synthases (eNOS and nNOS, respectively) expressed in M0 (unpolarized) macrophages. We showed that e/nNOS NO production downstream of bitter taste receptors enhances macrophage phagocytosis. In airway epithelial cells, we also showed that the activation of Akt by a small molecule (SC79) enhances NO production and increases levels of nuclear Nrf2, which reduces IL-8 transcription during concomitant stimulation with Toll-like receptor (TLR) 5 agonist flagellin. We hypothesized that SC79's production of NO in macrophages might likewise enhance phagocytosis and reduce the transcription of some pro-inflammatory cytokines. Using live cell imaging of fluorescent biosensors and indicator dyes, we found that SC79 induces Akt activation, NO production, and downstream cGMP production in primary human M0 macrophages. This was accompanied by a reduction in IL-6, IL-8, and IL-12 production during concomitant stimulation with bacterial lipopolysaccharide, an agonist of pattern recognition receptors including TLR4. Pharmacological inhibitors suggested that this effect was dependent on Akt and Nrf2. Together, these data suggest that several macrophage immune pathways are regulated by SC79 via Akt. A small-molecule Akt activator may be useful in some infection settings, warranting future in vivo studies.

Contrast-induced acute kidney injury: a review of definition, pathogenesis, risk factors, prevention and treatment

Contrast-induced acute kidney injury (CI-AKI) has become the third leading cause of hospital-acquired AKI, which seriously threatens the health of patients. To date, the precise pathogenesis of CI-AKI has remained not clear and may be related to the direct cytotoxicity, hypoxia and ischemia of medulla, and oxidative stress caused by iodine contrast medium, which have diverse physicochemical properties, including cytotoxicity, permeability and viscosity. The latest research shows that microRNAs (miRNAs) are also involved in apoptosis, pyroptosis, and autophagy which caused by iodine contrast medium (ICM), which may be implicated in the pathogenesis of CI-AKI. Unfortunately, effective therapy of CI-AKI is very limited at present. Therefore, effective prevention of CI-AKI is of great significance, and several preventive options, including hydration, antagonistic vasoconstriction, and antioxidant drugs, have been developed. Here, we review current knowledge about the features of iodine contrast medium, the definition, pathogenesis, molecular mechanism, risk factors, prevention and treatment of CI-AKI.

Ferroptosis in organ ischemia-reperfusion injuries: recent advancements and strategies

Ferroptosis is a newly discovered type of regulated cell death participated in multiple diseases. Different from other classical cell death programs such as necrosis and apoptosis, ferroptosis involving iron-catalyzed lipid peroxidation is characterized by Fe2+ accumulation and mitochondria alterations. The phenomenon of oxidative stress following organ ischemia-reperfusion (I/R) has recently garnered attention for its connection to the onset of ferroptosis and subsequent reperfusion injuries. This article provides a comprehensive overview underlying the mechanisms of ferroptosis, with a further focus on the latest research progress regarding interference with ferroptotic pathways in organ I/R injuries, such as intestine, lung, heart, kidney, liver, and brain. Understanding the links between ferroptosis and I/R injury may inform potential therapeutic strategies and targeted agents.

Lactobacillus reuteri mitigates hepatic ischemia/reperfusion injury by modulating gut microbiota and metabolism through the Nrf2/HO-1 signaling

BACKGROUND

This study seeks to investigate the impacts of Lactobacillus reuteri (L. reuteri) on hepatic ischemia-reperfusion (I/R) injury and uncover the mechanisms involved.

METHODS

Mice in the I/R groups were orally administered low and high doses of L.reuteri (L.reuteri-low and L. reuteri-hi; 1 × 1010 CFU/d and 1 × 1011 CFU/d), for 4 weeks prior to surgery. Following this, mice in the model group were treated with an Nrf2 inhibitor (ML-385), palmitoylcarnitine, or a combination of both.

RESULTS

After treatment with L. reuteri, mice exhibited reduced levels of serum aminotransferase (ALT), aspartate aminotransferase (AST), and myeloperoxidase (MPO) activity, as well as a lower Suzuki score and apoptosis rate. L. reuteri effectively reversed the I/R-induced decrease in Bcl2 expression, and the significant increases in the levels of Bax, cleaved-Caspase3, p-p65/p65, p-IκB/IκB, p-p38/p38, p-JNK/JNK, and p-ERK/ERK. Furthermore, the administration of L. reuteri markedly reduced the inflammatory response and oxidative stress triggered by I/R. This treatment also facilitated the activation of the Nrf2/HO-1 pathway. L. reuteri effectively counteracted the decrease in levels of beneficial gut microbiota species (such as Blautia, Lachnospiraceae NK4A136, and Muribaculum) and metabolites (including palmitoylcarnitine) induced by I/R. Likewise, the introduction of exogenous palmitoylcarnitine demonstrated a beneficial impact in mitigating hepatic injury induced by I/R. However, when ML-385 was administered prior to palmitoylcarnitine treatment, the previously observed effects were reversed.

CONCLUSION

L. reuteri exerts protective effects against I/R-induced hepatic injury, and its mechanism may be related to the promotion of probiotic enrichment, differential metabolite homeostasis, and the Nrf2/HO-1 pathway, laying the foundation for future clinical applications.

Hispolon inhibits neuronal ferroptosis by promoting the expression of Nrf-2

Research has shown that neuronal ferroptosis is associated with various central nervous system diseases, including Parkinson's disease, acute brain injury, and spinal cord injury. Inhibiting neuronal ferroptosis can greatly alleviate the progression of these diseases. However, there is currently a lack of effective drugs to inhibit neuronal ferroptosis. In this study, we pretreated neuronal cells with Hispolon and subsequently induced a neuronal ferroptosis model using Erastin. We further assessed the changes in the protein expression levels of SLC7A11, GPX4, ACSL4, Nrf-2, and HO-1 using Western blot and immunofluorescence techniques. Additionally, we measured the intracellular levels of Fe2+, GSH, and MDA using relevant assay kits. The research findings revealed that after Hispolon treatment, the expression of the pro-ferroptosis protein ACSL4 decreased, while the expression of the ferroptosis-regulating proteins GPX4 and SLC7A11 increased. Moreover, the use of an Nrf-2-specific inhibitor was able to reverse the effects of Hispolon as mentioned above. In this study, we discovered that Hispolon can promote the expression of Nrf-2 and inhibit the occurrence of neuronal ferroptosis induced by Erastin.

Deletion of protein kinase C θ attenuates hepatic ischemia/reperfusion injury and further elucidates its mechanism in pathophysiology

Objectives

Hepatic ischemia-reperfusion (HIR) is a severe process in pathophysiology that occurs clinically in hepatectomy, and hepatic transplantations. The present study aimed to investigate the effect of PKC θ deletion against HIR injury and elucidate its mechanism in pathophysiology.

Materials and Methods

HIR injury was induced in wild-type and PKC θ deletion mice treated with or without heme. The ALT and AST levels were determined to evaluate liver function. HIR injury was observed via histological examination. Oxidative stress and inflammatory response markers, and their signaling pathways were detected.

Results

The study found that PKC θ knockout decreased serum AST and ALT levels when compared to the WT mice. Furthermore, heme treatment significantly reduced the ALT and AST levels of the PKC θ deletion mice compared with the untreated PKC θ deletion mice. PKC θ deletion markedly elevated superoxide dismutase activity in the liver tissue, reduced malondialdehyde content in the tissue, and the serum TNF-α and IL-6 levels compared with the WT mice. Heme treatment was observed to elevate the activity of SOD and reduced MDA content and serum of TNF-α and IL 6 in the PKC θ deletion animals. Meanwhile, heme treatment increased HO-1 and Nrf 2 protein expression, and reduced the levels of TLR4, phosphorylated NF-κB, and IKB-α.

Conclusion

These findings suggested that PKC θ deletion ameliorates HIR, and heme treatment further improves HIR, which is related to regulation of PKC θ deletion on Nrf 2/HO-1 and TLR4/NF-κB/IKB α pathway.

Mechanism of action of certain medicinal plants for the treatment of asthma

ETHNOPHARMACOLOGICAL RELEVANCE

Asthma is often treated and prevented using the pharmacological properties of traditional medicinal plants. These healthcare systems are among the most well-known, conveniently accessible, and economically priced in India and several other Asian countries. Traditional Indian Ayurvedic plants have the potential to be used as phyto-therapeutics, to create novel anti-asthmatic drugs, and as a cost-effective source of pharmaceuticals. Current conventional therapies have drawbacks, including serious side effects and expensive costs that interfere with treatment compliance and affect the patient's quality of life. The primary objective of the article is to comprehensively evaluate the advancement of research on the protective phytochemicals of traditional plants that target immune responses and signaling cascades in inflammatory experimental asthma models. The study would assist in paving the way for the creation of natural phytomedicines that are protective, anti-inflammatory, and immunomodulatory against asthma, which may then be used in individualized asthma therapy.

AIM OF THE STUDY

The study demonstrates the mechanisms of action of phytochemicals present in traditional medicinal plants, diminish pulmonary disorder in both in vivo and in vitro models of asthma.

MATERIALS AND METHODS

A comprehensive review of the literature on conventional plant-based asthma therapies was performed from 2006 to 2022. The study uses authoritative scientific sources such as PubMed, PubChem Compound, Wiley Online Library, Science Direct, Springer Link, and Google Scholar to collect information on potential phytochemicals and their mechanisms of action. World Flora Online (http://www.worldfloraonline.org) and Plants of the World Online (https://wcsp.science.kew.org) databases were used for the scientific names of medicinal plants.

RESULTS

The study outlines the phytochemical mechanisms of some traditional Ayurveda botanicals used to treat asthma. Active phytochemicals including curcumin, withaferin-A, piperine, glabridin, glycyrrhizin, 18β-glycyrrhetinic acid, trans-cinnamaldehyde, α-hederin, thymoquinone, eugenol, [6]-shogoal, and gingerol may treat asthma by controlling inflammation and airway remodeling. The study concluded that certain Ayurvedic plants' phytochemicals have the ability to reduce inflammation and modulate the immune system, that can effectively cure asthma.

CONCLUSION

Plants used in traditional Ayurvedic medicine have been utilized for millennia, advocating phyto-therapy as a treatment for a variety of illnesses. A theoretical foundation for the use of cutting-edge asthma treatments has been built with the growth of experimental research on traditional phytochemicals. In-depth phytochemical research for the treatment of asthma using Indian Traditional Ayurvedic herbs is compiled in the study. The approach for preventative therapeutics and cutting-edge alternatives to battle the molecular pathways in the pathophysiology of asthma are the key themes of the study. The phytochemical mechanism of action of traditional Ayurvedic herbs is explained to get the attention of the pharmaceutical industry so they can make future anti-asthma drugs for personalized asthma care in the community. The study develops strategies for customized phyto-therapeutics, concentrating on low-cost, side-effect-free approaches that employ bioactive phytochemicals from plants as the major source of effective anti-asthmatic therapy.

Effects of astragaloside IV on glucocorticoid-induced avascular necrosis of the femoral head via regulating Akt-related pathways

We investigated the role of astragaloside IV (AS-IV) in preventing glucocorticoid-induced avascular necrosis of the femoral head (ANFH) and the underlying molecular mechanisms. Network pharmacology was used to predict the molecular targets of AS-IV. Molecular dynamic simulations were performed to explore the binding mechanism and interaction mode between AS-IV and Akt. Rat models of glucocorticoid-induced ANFH with AS-IV intervention were established, and osteogenesis, angiogenesis, apoptosis and oxidative stress were evaluated before and after blocking the PI3K/Akt pathway with LY294002. The effects of glucocorticoid and AS-IV on bone marrow mesenchymal stem cells and human umbilical vein endothelial cells incubated with and without LY294002 were determined. Downregulated p-Akt expression could be detected in the femoral heads of glucocorticoid-induced ANFH patients and rats. AS-IV increased trabecular bone integrity and vessel density of the femoral head in the model rats. AS-IV increased Akt phosphorylation and upregulated osteogenesis-, angiogenesis-, apoptosis- and oxidative stress-related proteins and mRNA and downregulated Bax, cleaved caspase-3 and cytochrome c levels. AS-IV promoted human umbilical vein endothelial cell migration, proliferation and tube formation ability; bone marrow mesenchymal stem cell proliferation; and osteogenic differentiation under glucocorticoid influence. AS-IV inhibited apoptosis. LY294002 inhibited these effects. AS-IV prevented glucocorticoid-induced ANFH by promoting osteogenesis and angiogenesis via the Akt/Runx2 and Akt/HIF-1α/VEGF pathways, respectively, and suppressing apoptosis and oxidative stress via the Akt/Bad/Bcl-2 and Akt/Nrf2/HO-1 pathways, respectively.

Farrerol Alleviates Hypoxic-Ischemic Encephalopathy by Inhibiting Ferroptosis in Neonatal Rats via the Nrf2 Pathway

Farrerol (FA) is a traditional Chinese herbal medicine known for its anti-inflammatory and anti-oxidative properties in various diseases. Ferroptosis is an iron-dependent oxidative stress-induced cell death. It is characterized by lipid peroxidation and glutathione depletion and is involved in neuronal injury. However, the role of FA in inhibiting ferroptosis in hypoxic-ischemic encephalopathy (HIE) and its underlying mechanisms are not yet completely elucidated. This study aimed to investigate whether FA could mediate ferroptosis and explore its function and molecular mechanism in HIE. A neonatal rat model of HIE was used, and rats were treated with FA, ML385 (a specific inhibitor of nuclear factor erythroid 2-related factor 2 [Nrf2]), or a combination of both. Neurological deficits, infarction volume, brain water content, pathological changes, and iron ion accumulation in the brain tissues were measured using the Zea-Longa scoring system and triphenyl tetrazolium chloride (TTC), hematoxylin-eosin (HE), and Perls' staining. The expression levels of GSH-Px, MDA, SOD, and ROS in brain tissues were also evaluated. Western blot analysis was performed to analyze the expression of the Nrf2 pathway and ferroptosis-related proteins. The results showed that FA administration significantly reduced neuronal damage, infarct volume, cerebral edema, and iron ion accumulation and inhibited MDA and ROS levels while promoting GSH-Px and SOD levels. FA also increased the expression levels of glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), Nrf2, and HO-1. Moreover, the combination of ML385 and FA in HIE abolished the FA protective effects. Therefore, the study concludes that FA exerts a neuroprotective effect after HIE by inhibiting oxidative stress and ferroptosis via the Nrf2 signaling pathway.

Tetramethylpyrazine ameliorates endotoxin-induced acute lung injury by relieving Golgi stress via the Nrf2/HO-1 signaling pathway

PURPOSE

Endotoxin-induced acute lung injury (ALI) is a severe disease caused by an imbalanced host response to infection. It is necessary to explore novel mechanisms for the treatment of endotoxin-induced ALI. In endotoxin-induced ALI, tetramethylpyrazine (TMP) provides protection through anti-inflammatory, anti-apoptosis, and anti-pyroptosis effects. However, the mechanism of action of TMP in endotoxin-induced ALI remains unclear. Here, we aimed to determine whether TMP can protect the lungs by inhibiting Golgi stress via the Nrf2/HO-1 pathway.

METHODS AND RESULTS

Using lipopolysaccharide (LPS)-stimulated C57BL/6J mice and MLE12 alveolar epithelial cells, we observed that TMP pretreatment attenuated endotoxin-induced ALI. LPS + TMP group showed lesser lung pathological damage and a lower rate of apoptotic lung cells than LPS group. Moreover, LPS + TMP group also showed decreased levels of inflammatory factors and oxidative stress damage than LPS group (P < 0.05). Additionally, LPS + TMP group presented reduced Golgi stress by increasing the Golgi matrix protein 130 (GM130), Golgi apparatus Ca2+/Mn2+ ATPases (ATP2C1), and Golgin97 expression while decreasing the Golgi phosphoprotein 3 (GOLPH3) expression than LPS group (P < 0.05). Furthermore, TMP pretreatment promoted Nrf2 and HO-1 expression (P < 0.05). Nrf2-knockout mice or Nrf2 siRNA-transfected MLE12 cells were pretreated with TMP to explore how the Nrf2/HO-1 pathway affected TMP-mediated Golgi stress in endotoxin-induced ALI models. We observed that Nrf2 gene silencing partially reversed the alleviating effect of Golgi stress and the pulmonary protective effect of TMP.

CONCLUSION

Our findings showed that TMP therapy reduced endotoxin-induced ALI by suppressing Golgi stress via the Nrf2/HO-1 signaling pathway in vivo and in vitro.

Lycopene attenuates chlorpyrifos-induced hepatotoxicity in rats via activation of Nrf2/HO-1 axis

Chlorpyrifos (CPF), is an organophosphate pesticide that is widely used for agricultural purposes. However, it has well-documented hepatotoxicity. Lycopene (LCP) is a plant-derived carotenoid with antioxidant and anti-inflammatory activities. The present work was designed to evaluate the potential hepatoprotective actions of LCP against CPF-induced hepatotoxicity in rats. Animals were assigned into five groups namely: Group I (Control), Group II (LCP), Group III (CPF), Group IV (CPF + LCP 5 mg/kg), and Group V (CPF + LCP 10 mg/kg). LCP offered protection as evidenced by inhibiting the rise in serum activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) induced by CPF. This was confirmed histologically as LCP-treated animals showed liver tissues with less proliferation of bile ducts and periductal fibrosis. LCP significantly prevented the rise in hepatic content of malondialdehyde (MDA), depletion of reduced glutathione (GSH), and exhaustion of glutathione-s-transferase (GST) and superoxide dismutase (SOD). Further, LCP significantly prevented hepatocyte death as it ameliorated the increase in Bax and the decrease in Bcl-2 expression induced by CPF in liver tissues as determined immunohistochemically. The observed protective effects of LCP were further confirmed by a significant enhancement in heme oxygenase-1 (HO-1) and NF-E2-related factor 2 (Nrf2) expression. In conclusion, LCP possesses protective effects against CPF-induced hepatotoxicity. These include antioxidation and activation of the Nrf2/HO-1 axis.

Association of nanoparticles and Nrf2 with various oxidative stress-mediated diseases

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regultes the cellular antioxidant defense system at the posttranscriptional level. During oxidative stress, Nrf2 is released from its negative regulator Kelch-like ECH-associated protein 1 (Keap1) and binds to antioxidant response element (ARE) to transcribe antioxidative metabolizing/detoxifying genes. Various transcription factors like aryl hydrocarbon receptor (AhR) and nuclear factor kappa light chain enhancer of activated B cells (NF-kB) and epigenetic modification including DNA methylation and histone methylation might also regulate the expression of Nrf2. Despite its protective role, Keap1/Nrf2/ARE signaling is considered as a pharmacological target due to its involvement in various pathophysiological conditions such as diabetes, cardiovascular disease, cancer, neurodegenerative diseases, hepatotoxicity and kidney disorders. Recently, nanomaterials have received a lot of attention due to their unique physiochemical properties and are also used in various biological applications, for example, biosensors, drug delivery systems, cancer therapy, etc. In this review, we will be discussing the functions of nanoparticles and Nrf2 as a combined therapy or sensitizing agent and their significance in various diseases such as diabetes, cancer and oxidative stress-mediated diseases.

Insights into the Molecular Mechanisms of NRF2 in Kidney Injury and Diseases

Redox is a constant phenomenon in organisms. From the signaling pathway transduction to the oxidative stress during the inflammation and disease process, all are related to reduction-oxidation (redox). Nuclear factor erythroid 2-related factor 2 (NRF2) is a transcription factor targeting many antioxidant genes. In non-stressed conditions, NRF2 maintains the hemostasis of redox with housekeeping work. It expresses constitutively with basal activity, maintained by Kelch-like-ECH-associated protein 1 (KEAP1)-associated ubiquitination and degradation. When encountering stress, it can be up-regulated by several mechanisms to exert its anti-oxidative ability in diseases or inflammatory processes to protect tissues and organs from further damage. From acute kidney injury to chronic kidney diseases, such as diabetic nephropathy or glomerular disease, many results of studies have suggested that, as a master of regulating redox, NRF2 is a therapeutic option. It was not until the early termination of the clinical phase 3 trial of diabetic nephropathy due to heart failure as an unexpected side effect that we renewed our understanding of NRF2. NRF2 is not just a simple antioxidant capacity but has pleiotropic activities, harmful or helpful, depending on the conditions and backgrounds.

Oxidative Stress and Air Pollution: Its Impact on Chronic Respiratory Diseases

Redox regulation participates in the control of various aspects of metabolism. Reactive oxygen and nitrogen species participate in many reactions under physiological conditions. When these species overcome the antioxidant defense system, a distressed status emerges, increasing biomolecular damage and leading to functional alterations. Air pollution is one of the exogenous sources of reactive oxygen and nitrogen species. Ambient airborne particulate matter (PM) is important because of its complex composition, which includes transition metals and organic compounds. Once in contact with the lungs' epithelium, PM components initiate the synthesis of inflammatory mediators, macrophage activation, modulation of gene expression, and the activation of transcription factors, which are all related to the physiopathology of chronic respiratory diseases, including cancer. Even though the pathophysiological pathways that give rise to the development of distress and biological damage are not fully understood, scientific evidence indicates that redox-dependent signaling pathways are involved. This article presents an overview of the redox interaction of air pollution inside the human body and the courses related to chronic respiratory diseases.

Fatty Liver/Adipose Tissue Dual-Targeting Nanoparticles with Heme Oxygenase-1 Inducer for Amelioration of Obesity, Obesity-Induced Type 2 Diabetes, and Steatohepatitis

Persistent uptake of high-calorie diets induces the storage of excessive lipid in visceral adipose tissue. Lipids secreted from obese adipose tissue are accumulated in peripheral tissues such as the liver, pancreas, and muscle, and impair insulin sensitivity causing type 2 diabetes mellitus (T2DM). Furthermore, the accumulation of inflammatory cytokines and lipids in the liver induces apoptosis and fibrogenesis, and ultimately causes nonalcoholic steatohepatitis (NASH). To modulate obese tissue environments, it is challenged to selectively deliver inducers of heme oxygenase-1 (HO-1) to adipose tissue with the aid of a prohibitin targeting drug delivery system. Prohibitin binding peptide (PBP), an oligopeptide targeting prohibitin rich in adipose tissue, is conjugated on the surface of Hemin- or CoPP-loaded poly(lactide-co-glycolide) nanoparticles (PBP-NPs). PBP-NPs efficiently differentiate lipid storing white adipocytes into energy-generating brown adipocytes in T2DM and NASH models. In addition, PBP-NPs are found to target prohibitin overexpressed fatty liver in the NASH model and inhibit hepatic uptake of circulating lipids. Furthermore, PBP-NPs switch phenotypes of inflammatory macrophages in damaged organs and lower inflammation. Taken together, dual-targeted induction of HO-1 in fatty adipose and liver tissues is proven to be a promising therapeutic strategy to ameliorate obesity, insulin resistance, and steatohepatitis by lowering lipids and cytokines.

Naringenin protects against iron overload-induced osteoarthritis by suppressing oxidative stress

BACKGROUND

The traditional Chinese medicine Gusuibu, the rhizome of Rhizoma Drynariae, is used to treat rheumatism and fractures. Naringenin (NAR) is an active ingredient in Gusuibu and has significant anti-inflammatory and antioxidant effects. However, the role of naringenin in iron overload-induced osteoarthritis (IOOA) is unknown.

HYPOTHESIS

NAR reduces cartilage damage in IOOA.

METHODS

The effects of NAR on the viability of IOOA chondrocytes and the synthesis ability of type II collagen were evaluated using cell counting kit (CCK8) and toluidine blue assays. To determine the mechanism of action and characteristics of NAR, the intracellular iron ion content, apoptosis rate, and mitochondrial membrane potential (MMP) change, and malondialdehyde (MDA) levels, as well as the degree of reactive oxygen species (ROS) and lipid hydroperoxide (LPO) accumulation in the cells were detected in vitro and verified using western blotting and quantitative real-time PCR (qRT-PCR). To verify the role of NAR in vivo, IOOA mice were established using iron dextran and surgery-induced destabilised medial meniscus. Changes in the articular cartilage and subchondral bone were examined using Safranin O-fast Green staining (S-O), haematoxylin-eosin staining (H&E), and microcomputed tomography (μCT).

RESULTS

In vitro, NAR attenuated the impairment of cell viability, apoptosis, and MMP caused by ferric ammonium citrate and interleukin-1β co-culture, increased the levels of MDA, reduced the expression of matrix metallopeptidase (MMP)3, MMP13, and Bax, and restored the expression of type II collagen (Col II). NAR showed a slight iron accumulation-reducing effect. NAR alleviated the accumulation of ROS and LPO in IOOA chondrocytes and upregulated antioxidant genes nuclear factor E2-related factor 2 (NRF2) and haem oxygenase 1 (HO-1). When ML385, a specific NRF-2 inhibitor, was added, the protective effect of NAR was significantly inhibited. In vivo, NAR reduced synovitis and attenuated cartilage damage and subchondral bone proliferation in IOOA mice.

CONCLUSIONS

NAR can reduce oxidative stress through the NRF2-HO-1 pathway, alleviate cartilage damage under iron overload, and has the potential to treat IOOA.

Cardiorenal dysfunction and hypertrophy induced by renal artery occlusion are normalized by galangin treatment in rats

Galangin is a polyphenolic compound found in Alpinia officinarum and propolis. This study investigated the effect of galangin on blood pressure, the renin angiotensin system (RAS), cardiac and kidney alterations and oxidative stress in two-kidney one-clipped (2K-1C) hypertensive rats. Hypertension was induced in male Sprague Dawley rats (180-220 g), and the rats were given galangin (30 and 60 mg/kg) and losartan (10 mg/kg) for 4 weeks (n = 8/group). Galangin decreased hypertension and cardiac dysfunction and hypertrophy, which was related to the reducing circulation angiotensin converting enzyme (ACE) activity and angiotensin II concentration (p < 0.05). These effects were consistent with the reduced overexpression of angiotensin II receptor type 1 (AT₁R), transforming growth factor beta 1 (TGF-β1) and collagen type I (Col I) protein in cardiac tissue (p < 0.05). Additionally, renal artery occlusion, procedure-induced kidney dysfunction and fibrosis were attenuated in the galangin-treated group. Galangin treatment normalized the overexpression of AT₁R and NADPH oxidase 4 (Nox-4) protein and normalized the downregulation of nuclear factor-erythroid Factor 2-related Factor 2 (Nrf-2) and haem oxygenase 1 (HO-1) in 2K-1C rats (p < 0.05). Galangin exhibited antioxidative effects, as it reduced systemic and tissue oxidative stress markers and increased catalase activity in 2K-1C rats (p < 0.05). In conclusion, galangin attenuated hypertension, renin-angiotensin system activation, cardiorenal damage and oxidative stress induced by renal artery stenosis in rats. These effects might be associated with modulation of the expression of AT₁R, TGF-β1 and Col I protein in the heart as well as AT₁R/Nox-4 and Nrf-2/HO-1 protein in renal tissue in hypertensive rats.

The Role of Ferroptosis in the Damage of Human Proximal Tubule Epithelial Cells Caused by Perfluorooctane Sulfonate

Perfluorooctane sulfonate (PFOS) is a typical persistent organic pollutant and environmental endocrine disruptor that has been shown to be associated with the development of many diseases; it poses a considerable threat to the ecological environment and to human health. PFOS is known to cause damage to renal cells; however, studies of PFOS-induced ferroptosis in cells have not been reported. We used the CCK-8 method to detect cell viability, flow cytometry and immunofluorescence methods to detect ROS levels and Western blot to detect ferroptosis, endoplasmic reticulum stress, antioxidant and apoptosis-related proteins. In our study, we found that PFOS could induce the onset of ferroptosis in HK-2 cells with decreased GPx4 expression and elevated ACSL4 and FTH1 expression, which are hallmarks for the development of ferroptosis. In addition, PFOS-induced ferroptosis in HK-2 cells could be reversed by Fer-1. We also found that endoplasmic reticulum stress and its mediated apoptotic mechanism and P53-mediated antioxidant mechanism are involved in the toxic damage of cells by PFOS. In this paper, we demonstrated for the first time that PFOS can induce ferroptosis in HK-2 cells. In addition, we preliminarily explored other mechanisms of cytotoxic damage by PFOS, which provides a new idea to study the toxicity of PFOS as well as the damage to the kidney and its mechanism.

STAT6 inhibits ferroptosis and alleviates acute lung injury via regulating P53/SLC7A11 pathway

Compelling evidences have revealed the emerging role of ferroptosis in the pathophysiological process of acute lung injury (ALI), but its modulation is not clear. Here, we identified that STAT6 acted as a critical regulator of epithelium ferroptosis during ALI. Firstly, STAT6 expression and activity were increased in the ALI mice models caused by crystalline silica (CS), LPS and X-ray exposure. Followed by confirming the contribution of ferroptosis in the above ALI with ferrostatin-1 and deferoxamine intervention, bioinformatic analyses revealed that STAT6 expression was negatively correlated with ferroptosis. Consistently, lung epithelium-specific depletion of STAT6 in mice or STAT6 knockdown in cultured epithelial cells exacerbated ferroptosis in the above ALI. While overexpression of STAT6 in lung epithelial cells attenuated the ferroptosis. Mechanistically, SLC7A11 is a typical ferroptosis-related gene and negatively regulated by P53. CREB-binding protein (CBP) is a critical acetyltransferase of P53 acetylation, showing valuable regulation on targets' transcription. Herein, we found that STAT6 negatively regulates ferroptosis through competitively binding with CBP, which inhibits P53 acetylation and transcriptionally restores SLC7A11 expression. Finally, pulmonary-specific STAT6 overexpression decreased the ferroptosis and attenuated CS and LPS induced lung injury. Our findings revealed that STAT6 is a pivotal regulator of ferroptosis, which may be a potential therapeutic target for the treatment of acute lung injury.

The effect of icariin on autoimmune premature ovarian insufficiency via modulation of Nrf2/HO-1/Sirt1 pathway in mice

Primary ovarian insufficiency (POI) is a common gynecological disease. Autoimmunity is a common cause of POI. Icariin (ICA) plays a therapeutic role in many autoimmune diseases. This study aims to investigate the effect of ICA on autoimmune POI mice and its effect on immune regulation. Sixty-three female BALB/c mice were randomized into three groups (control, POI, POI + ICA). POI and POI + ICA group were hypodermically injected with zona pellucida three peptides (pZP3) to induce autoimmune POI. Then the POI + ICA group was gavaged with ICA. A vaginal smear was to observe estrous cycles, hematoxylin-eosin staining was to count follicles. Enzyme-linked immunosorbent analysis determined serum FSH, LH, AMH, and anti-zona pellucida antibody (AZPAb) levels. In addition, flow cytometry detected the expression of Th1 cells and Treg cells, and Western blot was used to detect the expression of Nuclear factor E2 related factor 2(Nrf2), heme oxygenase-1 (HO-1), and Sirtuin-1 (Sirt1) proteins. pZP3 treatment decreased serum AMH levels and increased FSH, LH, and AZPAb levels. Additionally, decreases in the number of healthy follicles at all stages and an increase in the number of atretic follicles. Abnormal ovarian structure and an arrested estrous cycle were also noted. However, ICA rescued POI through up-regulating Nrf2, HO-1, and Sirt1 expressions and up-regulating Treg expressions. ICA treatment improved the structure of the injured ovarian and its function in autoimmune POI mice. The mechanism is achieved by increasing the expression of Nrf2/HO-1/Sirt1 pathway in the ovary and increasing Treg cells' expression.

Imbalance of alveolar epithelial type I and type Ⅱ cells in lipopolysaccharide-induced chronic lung injury young mouse model

Children are susceptible to pneumonia, which affects their growth and development. Immune disorders and unrepaired alveolar mucosal epithelium following pneumonia cause chronic lung injury. The mechanism of chronic lung injury is unknown and lacks animal models for reference. Therefore, we developed a chronic lung injury young mouse model to simulate the pathological process of children. 3-week-old mice were intratracheal instillation of lipopolysaccharide (LPS) every other day for six weeks. Consequently, the histopathology showed damaged integrity of lung tissue, fibrosis, and abnormally distributed alveolar epithelial cells. The total protein concentration in bronchoalveolar lavage fluid (BALF) was increased, alveolar epithelial type (AT) I cells were abnormal distribution, and AT II cells were reduced. The phosphorylation levels of IKBα and the expression levels of NF-κB p65 in lung tissue were up-regulated. In serum and BALF, the IL-6 was oversecretion, nitric oxide (NO) and superoxide dismutase (SOD) were perturbed secretion, oxidative stress imbalance. In addition, blood viscosity, plasma viscosity, and erythrocyte sedimentation rate (ESR) indexes in hemorheology were increased. In conclusion, it is feasible to construct the mouse model of chronic lung injury, and AT I and AT Ⅱ cells were imbalanced, which paves the way for further investigations on the pathogenesis of chronic lung injury and the efficacy of novel treatments.

SIRT6 Activator UBCS039 Inhibits Thioacetamide-Induced Hepatic Injury In Vitro and In Vivo

SIRT6 has been reported to have multiple functions in inflammation and metabolism. In the present study, we explored the regulatory effects and mechanisms of SIRT6 in thioacetamide (TAA)-induced mice acute liver failure (ALF) models. The SIRT6 activator UBCS039 was used in this animal and cell experiments. We observed that UBCS039 ameliorated liver damage, including inflammatory responses and oxidative stress. Further study of mechanisms showed that the upregulation of SIRT6 inhibited the inflammation reaction by suppressing the nuclear factor-κB (NF-κB) pathway in the TAA-induced ALF mice model and lipopolysaccharide-stimulated macrophages. In addition, the upregulation of SIRT6 alleviated oxidative stress damage in hepatocytes by regulating the Nrf2/HO-1 pathway. These findings demonstrate that pharmacologic activator of SIRT6 could be a promising target for ALF.

Postconditioning with Irisin Attenuates Lung Ischemia/Reperfusion Injury by Suppressing Ferroptosis via Induction of the Nrf2/HO-1 Signal Axis

Iron-dependent lipid peroxidation causes ferroptosis. This study was aimed at verifying that irisin postconditioning can inhibit ferroptosis and minimize lung ischemia/reperfusion (I/R) damage via activating the Nrf2/HO-1 signal axis. We constructed a murine model of I/R lung damage. At the onset of reperfusion, irisin, ferroptosis inhibitor ferrostatin-1, and ferroptosis inducer Fe-citrate were all administered. We discovered that irisin could reduce lung I/R injury, consistent with ferrostatin-1's action. Furthermore, irisin suppressed ferroptosis in lung I/R damage, as evidenced by lower ROS, MDA, and Fe²⁺, as well as alterations in critical protein expression (GPX4 and ACSL4). However, Fe-citrate abolished the protective effects of irisin. Transcriptome research found that irisin increased the mRNA levels of Nrf2 and HO-1. Thus, we used siRNA to investigate the role of the Nrf2/HO-1 axis in irisin-mediated protection against hypoxia/reoxygenation (H/R) damage in MLE-12 cells. Irisin consistently reduced ferroptosis and improved mitochondrial dysfunction caused by H/R. Irisin's cytoprotective function was eliminated when Nrf2 was silenced. As a result, irisin postconditioning may protect against lung I/R damage by suppressing ferroptosis via the Nrf2/HO-1 signaling axis.

Exogenous spermine inhibits high glucose/oxidized LDL‑induced oxidative stress and macrophage pyroptosis by activating the Nrf2 pathway

Evidence suggests that macrophage pyroptosis promotes the progression of diabetic atherosclerosis. Spermine, a natural cellular metabolite, demonstrates a protective effect against cardiovascular diseases. However, whether spermine has a protective effect against macrophage pyroptosis caused by high glucose (HG) and oxidized low-density lipoprotein (ox-LDL) conditions remains to be elucidated. To investigate the protective effect of spermine and the related underlying mechanism, THP-1 macrophages were treated with HG/ox-LDL, spermine, or the specific nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor ML385. Cell viability was detected using CCK-8, cell membrane permeability was analyzed using lactate dehydrogenase (LDH) and Hoechst/propidium iodide staining and pyroptosis-related gene and protein expression levels were evaluated using polymerase chain reaction and western blot analysis. Spermine showed a potent preventive effect on THP-1 macrophage pyroptosis and oxidative stress induced by HG/ox-LDL. Cells treated with spermine showed increased cell viability, reduced reactive oxygen species (ROS) production, decreased LDH levels in the supernatant and reduced cell swelling. In addition, spermine significantly reduced NLR family pyrin domain containing 3, cleaved caspase-1, N-gasdermin D and IL-1β expression, as well as IL-1β levels in the supernatant. This demonstrated that the inhibition of pyroptosis and oxidative stress due to spermine was Nrf2 dependent. Furthermore, spermine enhanced Nrf2 nuclear translocation, thereby increasing heme oxygenase-1 and NADPH quinone oxidoreductase-1 expression, which subsequently reduced ROS production. In addition, the anti-pyroptotic and antioxidant effects of spermine were reversed by ML385 inhibition of Nrf2. It was concluded that spermine prevented macrophage pyroptosis and increased ROS overproduction by activating the Nrf2 pathway. The data suggested that spermine may be a potential novel drug for the treatment of diabetic atherosclerosis because it targets macrophage pyroptosis.

Antioxidant Effects of Statins by Modulating Nrf2 and Nrf2/HO-1 Signaling in Different Diseases

Statins are competitive inhibitors of hydroxymethylglutaryl-CoA (HMG-CoA) reductase and have been used to treat elevated low-density lipoprotein cholesterol (LDL-C) for almost four decades. Antioxidant and anti-inflammatory properties which are independent of the lipid-lowering effects of statins, i.e., their pleiotropic effects, might be beneficial in the prevention or treatment of many diseases. This review discusses the antioxidant effects of statins achieved by modulating the nuclear factor erythroid 2 related factor 2/ heme oxygenase-1 (Nrf2/HO-1) pathway in different organs and diseases. Nrf2 and other proteins involved in the Nrf2/HO-1 signaling pathway have a crucial role in cellular responses to oxidative stress, which is a risk factor for ASCVD. Statins can significantly increase the DNA-binding activity of Nrf2 and induce the expression of its target genes, such as HO-1 and glutathione peroxidase) GPx, (thus protecting the cells against oxidative stress. Antioxidant and anti-inflammatory properties of statins, which are independent of their lipid-lowering effects, could be partly explained by the modulation of the Nrf2/HO-1 pathway.

Comparative Efficiency of Lutein and Astaxanthin in the Protection of Human Corneal Epithelial Cells In Vitro from Blue-Violet Light Photo-Oxidative Damage

The aim of this study was to compare in vitro the protective and antioxidant properties of lutein and astaxanthin on human primary corneal epithelial cells (HCE-F). To this purpose, HCE-F cells were irradiated with a blue-violet light lamp (415–420 nm) at different energies (20 to 80 J/cm2). Lutein and astaxanthin (50 to 250 μM) were added to HCE-F right before blue-violet light irradiation at 50 J/cm2. Viability was evaluated by the CKK-8 assay while the production of reactive oxygen species (ROS) by the H2DCF-DA assay. Results have shown that the viability of HCE-F cells decreased at light energies from 20 J/cm2 to 80 J/cm2, while ROS production increased at 50 and 80 J/cm2. The presence of lutein or astaxanthin protected the cells from phototoxicity, with lutein slightly more efficient than astaxanthin also on the blunting of ROS, prevention of apoptotic cell death and modulation of the Nrf-2 pathway. The association of lutein and astaxanthin did not give a significant advantage over the use of lutein alone. Taken together, these results suggest that the association of lutein and astaxanthin might be useful to protect cells of the ocular surface from short (lutein) and longer (astaxanthin) wavelengths, as these are the most damaging radiations hitting the eye from many different LED screens and solar light.

Oral streptococci subvert the host innate immune response through hydrogen peroxide

In periodontal health, oral streptococci constitute up to 80% of the plaque biofilm. Yet, destructive inflammatory events of the periodontium are rare. This observation suggests that oral streptococci may possess mechanisms to co-exist with the host. However, the mechanisms employed by oral streptococci to modulate the innate immune response have not been well studied. One of the key virulence factors produced by oral streptococci is hydrogen peroxide (H₂O₂). In mammalian cells, H₂O₂ triggers the activation of nuclear factor erythroid 2-related factor 2 (Nrf2), a key pathway mediating antioxidant defence. This study aimed to determine (1) if H₂O₂ producing oral streptococci activated the Nrf2 pathway in macrophages, and (2) if the activation of Nrf2 influenced the innate immune response. We found that oral streptococci downregulated the innate immune response in a H₂O₂ dependent manner through the activation of the Nrf2. The activation of the Nrf2 signalling pathway led to the inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (NFĸB), the key transcription factor regulating pro-inflammatory response. This study showed for the first time that oral streptococci are unlikely passive bystanders but could play an active role in the maintenance of periodontal health by preventing overt inflammation.

The V-ATPases in cancer and cell death

Transmembrane ATPases are membrane-bound enzyme complexes and ion transporters that can be divided into F-, V-, and A-ATPases according to their structure. The V-ATPases, also known as H⁺-ATPases, are large multi-subunit protein complexes composed of a peripheral domain (V1) responsible for the hydrolysis of ATP and a membrane-integrated domain (V0) that transports protons across plasma membrane or organelle membrane. V-ATPases play a fundamental role in maintaining pH homeostasis through lysosomal acidification and are involved in modulating various physiological and pathological processes, such as macropinocytosis, autophagy, cell invasion, and cell death (e.g., apoptosis, anoikis, alkaliptosis, ferroptosis, and lysosome-dependent cell death). In addition to participating in embryonic development, V-ATPase pathways, when dysfunctional, are implicated in human diseases, such as neurodegenerative diseases, osteopetrosis, distal renal tubular acidosis, and cancer. In this review, we summarize the structure and regulation of isoforms of V-ATPase subunits and discuss their context-dependent roles in cancer biology and cell death. Updated knowledge about V-ATPases may enable us to design new anticancer drugs or strategies.

Ferroptosis in Intracerebral Hemorrhage: A Panoramic Perspective of the Metabolism, Mechanism and Theranostics

Iron is one of the most crucial elements in the human body. In recent years, a kind of programmed, non-apoptotic cell death closely related to iron metabolism-called ferroptosis- has aroused much interest among many scientists. Ferroptosis also interacts with other pathways involved in cell death including iron abnormality, the cystine/glutamate antiporter and lipid peroxidation. Together these pathological pathways exert great impacts on intracerebral hemorrhage (ICH), a lethal cerebrovascular disease with a high incidence rate and mortality rate. Furthermore, the ferroptosis also affects different brain cells (neurons and neuroglial cells) and different organelles (mitochondria and endoplasmic reticulum). Clinical treatments for ferroptosis in ICH have been closely investigated recently. This perspective provides a comprehensive summary of ferroptosis mechanisms after ICH and its interaction with other cell death patterns. Understanding the role of ferroptosis in ICH will open new windows for the future treatments and preventions for ICH and other intracerebral diseases.

Menthol Targeting AMPK Alleviates the Inflammatory Response of Bovine Mammary Epithelial Cells and Restores the Synthesis of Milk Fat and Milk Protein

Mastitis is one of the most serious diseases that causes losses in the dairy industry, seriously impairing milk production and milk quality, and even affecting human health. Menthol is a cyclic monoterpene compound obtained from the stem and leaves of peppermint, which has a variety of biological activities, including anti-inflammatory and antioxidant activity. The purpose of this study was to investigate the preventive effect of menthol on the lipopolysaccharide-induced inflammatory response in primary bovine mammary gland epithelial cells (BMECs) and its anti-inflammatory mechanism. First, BMECs were isolated and amplified from the udders of Holstein cows by enzymatic hydrolysis. BMECs were treated with menthol (10, 50, 100, 200 μM) for 1h, followed by lipopolysaccharide (5μg/ml) for 12 h. Lipopolysaccharide treatment upregulated the protein levels of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (INOS) and the mRNA abundance of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β), while menthol was able to inhibit this effect. The inhibitory effect of menthol on proinflammatory factors was significantly reduced when autophagy was blocked using 3-Methyladenine (5μg/ml), an inhibitor of autophagy. Furthermore, lipopolysaccharide treatment reduced the expression levels of milk lipids and milk proteins, which were inhibited by menthol. In addition, menthol (200 μM) treatment was able to significantly upregulate the expression level of autophagy-related protein LC3B, downregulate the expression level of P62, promote the expression abundance of autophagy-related gene mRNA, and enhance significantly enhance autophagic flux. Interestingly, treatment of BMECs with menthol (200 μM) promoted the phosphorylation of AMP-activated protein kinase (AMPK) and unc-51 like kinase 1 (ULK1) and increased the nuclear localization of nuclear factor-E2 associated factor 2 (Nrf-2). When the AMPK pathway was blocked using compound C (10μg/ml), an inhibitor of AMPK, autophagy was significantly inhibited. Autophagy levels were significantly decreased after blocking the Nrf-2 pathway using ML385 (5μg/ml), an inhibitor of Nrf-2. Overall, the data suggest that menthol activates the AMPK-ULK1 pathway to initiate the onset of autophagy and maintains the level of autophagy through the AMPK-Nrf-2 pathway. In conclusion, the findings suggest that menthol may alleviate the inflammatory response in BMECs via the AMPK/ULK1/Nrf-2/autophagy pathway.

COVID19 Disease Map, a computational knowledge repository of virus-host interaction mechanisms

We need to effectively combine the knowledge from surging literature with complex datasets to propose mechanistic models of SARS-CoV-2 infection, improving data interpretation and predicting key targets of intervention. Here, we describe a large-scale community effort to build an open access, interoperable and computable repository of COVID-19 molecular mechanisms. The COVID-19 Disease Map (C19DMap) is a graphical, interactive representation of disease-relevant molecular mechanisms linking many knowledge sources. Notably, it is a computational resource for graph-based analyses and disease modelling. To this end, we established a framework of tools, platforms and guidelines necessary for a multifaceted community of biocurators, domain experts, bioinformaticians and computational biologists. The diagrams of the C19DMap, curated from the literature, are integrated with relevant interaction and text mining databases. We demonstrate the application of network analysis and modelling approaches by concrete examples to highlight new testable hypotheses. This framework helps to find signatures of SARS-CoV-2 predisposition, treatment response or prioritisation of drug candidates. Such an approach may help deal with new waves of COVID-19 or similar pandemics in the long-term perspective.

Crocetin Exerts Its Anti-inflammatory Property in LPS-Induced RAW264.7 Cells Potentially via Modulation on the Crosstalk between MEK1/JNK/NF-κB/iNOS Pathway and Nrf2/HO-1 Pathway

Crocetin is a main bioactive component with a carotenoid skeleton in Gardenia jasminoides, a typical traditional Chinese medicine with a long history in Southeast Asia. Crocetin is being commonly consumed as spices, dyes, and food colorants. Recent pharmacological studies had implied that crocetin may possess potent anti-inflammatory properties; however, the underlying molecular mechanism is not fully elucidated. In the present study, the regulatory effect of crocetin on redox balance was systematically investigated in lipopolysaccharide- (LPS-) stimulated RAW264.7 cells. The results showed that crocetin dose-dependently inhibited LPS-induced nitric oxide production and inducible nitric oxide synthase (iNOS) expression in RAW264.7 cells. Molecular data revealed that crocetin exerted its anti-inflammatory property by inhibiting the MEK1/JNK/NF-κB/iNOS pathway and activating the Nrf2/HO-1 pathway. The shRNA-knockdown (KD) of MEK1 and ERK1 confirmed that the activation of MEK1 and inhibition of JNK mediated the anti-inflammatory effect of crocetin. Moreover, the pull-down assay and computational molecule docking showed that crocetin could directly bind to MEK1 and JNK1/2. It is noticed that both KD and knockout (KO) of HO-1 gene blocked this action. More detailed data have shown that HO-1-KO blocked the inhibition of p-IκB-α by crocetin. These data indicated that crocetin exerted its anti-inflammatory property via modulating the crosstalk between the MEK1/JNK/NF-κB/iNOS pathway and the Nrf2/HO-1 pathway, highlighting HO-1 as a major player. Therefore, the present study reveals that crocetin can act as a potential candidate for redox-balancing modulation in charge of its anti-inflammatory and chemopreventive effect, which strengthens its potency in the subsequent clinic application in the near future.

Ferroptosis, a New Insight Into Acute Lung Injury

Acute lung injury (ALI), a common and critical illness with high morbidity and mortality, is caused by multiple causes. It has been confirmed that oxidative stress plays an important role in the development of ALI. Ferroptosis, a newly discovered programmed cell death in 2012, is characterized by iron-dependent lipid peroxidation and involved in many diseases. To date, compelling evidence reveals the emerging role of ferroptosis in the pathophysiological process of ALI. Here, we review the role of ferroptosis in the pathogenesis of ALI and its therapeutic potential in ALI.

Heme Oxygenase-1 Induction by Cobalt Protoporphyrin Ameliorates Cholestatic Liver Disease in a Xenobiotic-Induced Murine Model

Cholestatic liver diseases can progress to end-stage liver disease and reduce patients' quality of life. Although their underlying mechanisms are still incompletely elucidated, oxidative stress is considered to be a key contributor to these diseases. Heme oxygenase-1 (HO-1) is a cytoprotective enzyme that displays antioxidant action. It has been found that this enzyme plays a protective role against various inflammatory diseases. However, the role of HO-1 in cholestatic liver diseases has not yet been investigated. Here, we examined whether pharmacological induction of HO-1 by cobalt protoporphyrin (CoPP) ameliorates cholestatic liver injury. To this end, a murine model of 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet feeding was used. Administration of CoPP ameliorated liver damage and cholestasis with HO-1 upregulation in DDC diet-fed mice. Induction of HO-1 by CoPP suppressed the DDC diet-induced oxidative stress and hepatocyte apoptosis. In addition, CoPP attenuated cytokine production and inflammatory cell infiltration. Furthermore, deposition of the extracellular matrix and expression of fibrosis-related genes after DDC feeding were also decreased by CoPP. HO-1 induction decreased the number of myofibroblasts and inhibited the transforming growth factor-β pathway. Altogether, these data suggest that the pharmacological induction of HO-1 ameliorates cholestatic liver disease by suppressing oxidative stress, hepatocyte apoptosis, and inflammation.

Ethyl pyruvate: A newly discovered compound against ischemia-reperfusion injury in multiple organs

Ischemia-reperfusion injury (IRI) is a process whereby an initial ischemia injury and subsequent recovery of blood flow, which leads to the propagation of an innate immune response and the changes of structural and functional of multiple organs. Therefore, IRI is considered to be a great challenge in clinical treatment such as organ transplantation or coronary angioplasty. In recent years, ethyl pyruvate (EP), a derivative of pyruvate, has received great attention because of its stability and low toxicity. Previous studies have proved that EP has various pharmacological activities, including anti-inflammation, anti-oxidative stress, anti-apoptosis, and anti-fibrosis. Compelling evidence has indicated EP plays a beneficial role in a variety of acute injury models, such as brain IRI, myocardial IRI, renal IRI, and hepatic IRI. Moreover, EP can not only effectively inhibit multiple IRI-induced pathological processes, but also improve the structural and functional lesion of tissues and organs. In this study, we review the recent progress in the research on EP and discuss their implications for a better understanding of multiple organ IRI, and the prospects of targeting the EP for therapeutic intervention.

A new ferroptosis inhibitor, isolated from Ajuga nipponensis, protects neuronal cells via activating NRF2-antioxidant response elements (AREs) pathway

Ferroptosis is a new form of cell death, and inhibition of ferroptosis is a promising strategy to treat neurological diseases. In this work, sixteen compounds were isolated from Ajuga nipponensis and assayed for anti-ferroptosis activity in HT22 mouse hippocampal neuronal cells. Ajudecunoid C (1, ADC), a new neoclerodane diterpenoid, showed significant inhibitory activity against erastin and RSL3-induced ferroptosis with EC₅₀ values of 4.1 ± 1.0 and 3.6 ± 0.3 μM, respectively. Experimental results demonstrated that ADC effectively prevented ferroptosis through scavenging free radical and activating NRF2-antioxidant response elements (AREs) pathway. This study reveals that ADC, as a new ferroptosis inhibitor, is a promising lead compound for the development of drugs against ferroptosis-related neurological diseases.

Nobiletin Decreases Inflammatory Mediator Expression in Tumor Necrosis Factor-Stimulated Human Periodontal Ligament Cells

Nobiletin, a biologically active substance in the skin of citrus fruits, has been reported to be an effective anti-inflammatory, anticancer, and antimicrobial agent. In this study, we aimed to examine the anti-inflammatory effects of nobiletin on tumor necrosis factor- (TNF-) stimulated human periodontal ligament cells (HPDLCs). Our results demonstrated that nobiletin treatment could decrease the expressions of inflammatory cytokines (C-X-C motif chemokine ligand (CXCL)10, C-C motif chemokine ligand (CCL)2, and interleukin- (IL-) 8), matrix metalloproteinases (MMPs) (MMP1 and MMP3), and prostaglandin-endoperoxide synthase 2 (PTGS2) in TNF-stimulated HPDLCs. Moreover, we revealed that nobiletin could inhibit the activation of nuclear factor- (NF-) κB and protein kinase B (AKT1) pathways in TNF-stimulated HPDLCs. Furthermore, nobiletin treatment enhanced nuclear factor, erythroid 2 like 2 (NFE2L2) and heme oxygenase 1 (HMOX1) expressions in TNF-stimulated HPDLCs. In conclusion, these findings suggest that nobiletin can inhibit inflammatory responses in TNF-stimulated HPDLCs by inhibiting NF-κB and AKT1 activations and upregulating the NFE2L2 and HMOX1 expression.

β-Glucan from Saccharomyces cerevisiae alleviates oxidative stress in LPS-stimulated RAW264.7 cells via Dectin-1/Nrf2/HO-1 signaling pathway

β-Glucan from Saccharomyces cerevisiae has been described to be effective antioxidants, but the specific antioxidation mechanism of β-glucan is unclear. The objectives of this research were to determine whether the β-glucan from Saccharomyces cerevisiae could regulate oxidative stress through the Dectin-1/Nrf2/HO-1 signaling pathway in lipopolysaccharides (LPS)-stimulated RAW264.7 cells. In this study, we examined the effects of β-glucan on the enzyme activity or production of oxidative stress indicators in LPS-stimulated RAW264.7 cells by biochemical analysis and the protein expression of key factors of Dectin-1/Nrf2/HO-1 signaling pathway by immunofluorescence and western blot. The biochemical analysis results showed that β-glucan increased the LPS-induced downregulation of enzyme activity of intracellular heme oxygenase (HO), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) while decreasing the production of reactive oxygen species (ROS) and malondialdehyde (MDA). Furthermore, immunofluorescence results showed that β-glucan can activate the nuclear factor erythroid 2-related factor 2 (Nrf2). The antioxidant mechanism study indicated that β-glucan activated dendritic-cell-associated C-type lectin 1 (Dectin-1) receptors mediated Nrf2/HO-1 signaling pathway, thereby downregulating the production of ROS and thus produced the antioxidant effects in LPS-stimulated RAW 264.7 cells. In conclusion, these results indicate that β-glucan potently alleviated oxidative stress via Dectin-1/Nrf2/HO-1 in LPS-stimulated RAW 264.7 cells.

Suppressive role of microRNA-130b-3p in ferroptosis in melanoma cells correlates with DKK1 inhibition and Nrf2-HO-1 pathway activation

Cell death pathways related to ferroptosis are implicated in the progression of melanoma. Emerging data reporting the upregulation of microRNA (miR)-130b-3p in melanoma indicate the potential implication of miR-130b-3p in this malignancy. Herein, we aimed to identify whether and how miR-130b-3p regulated ferroptosis in melanoma cells. Melanoma cells (A375, G-361) were treated with erastin or RSL3 to mimic ferroptosis in vitro. Viability, lipid peroxidation level and ferrous ion content in melanoma cells were then assessed in response to manipulation of miR-130b-3p expression. Luciferase assay was conducted to determine the binding of miR-130b-3p to Dickkopf1 (DKK1). Western blot assay was conducted to determine the expression of molecules related to nuclear factor-erythroid 2 p45-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway. The results indicated that miR-130b-3p exerted an inhibitory role in erastin or RSL3-induced ferroptosis, evidenced by reductions in lipid peroxidation and ferrous ion content. By suppressing the expression of target gene DKK1, miR-130b-3p activated the Nrf2/HO-1 pathway, whereby repressing ferroptosis. miR-130b-3p blocked the antitumor activity of erastin. Further, in vitro findings were reproduced in an in vivo murine model. Together, these data suggest the potential of miR-130b-3p to inhibit ferroptosis in melanoma cells and the mechanism was related to DKK1-mediated Nrf2/HO-1 pathway.

Maresin 1 alleviates the inflammatory response, reduces oxidative stress and protects against cardiac injury in LPS-induced mice

BACKGROUND

Maresin 1 (MaR1) is a pro-resolving lipid mediator that has been reported to have strong regulatory effects on oxidative stress and inflammation. This study aimed to determine the effect of MaR1 on lipopolysaccharide (LPS)-induced sepsis-related cardiac injury and explore its possible mechanisms.

METHODS

Mice were administered MaR1 or PBS and then treated with LPS or saline for 6 h. Then, cardiac function, cardiac injury markers, cardiac macrophage differentiation, oxidative stress and myocardial cell apoptosis in each group were measured.

RESULTS

MaR1 treatment significantly decreased the serum levels of lactate dehydrogenase (LDH) and kinase isoenzyme (CK-MB) and improved cardiac function in LPS-induced mice. Treatment with MaR1 also inhibited LPS-induced M1 macrophage differentiation and reduced M1 macrophage-related cytokine secretion while promoting M2 macrophage differentiation and increasing M2 macrophage-related inflammatory mediator expression. In addition, MaR1 decreased serum malondialdehyde (MDA) levels and increased serum levels of superoxide dismutase (SOD) and glutathione (GSH), as well as cardiac expression of nuclear factor erythroid-2 related factor 2 (Nrf-2) and heme oxygenase 1 (HO-1), in LPS-induced mice. Furthermore, fewer TUNEL-positive cells were observed in the LPS + MaR1 group than in the LPS group.

CONCLUSIONS

Our experimental results show that MaR1 alleviates cardiac injury and protects against cardiac dysfunction and may be beneficial in reducing sepsis-induced cardiac injury.

MitoQ alleviates LPS-mediated acute lung injury through regulating Nrf2/Drp1 pathway

Lipopolysaccharide (LPS) has been known to cause alveolar epithelial cell (AEC) apoptosis and barrier breakdown that characterize acute lung injury (ALI) and acute respiratory distress syndrome. We aimed to investigate whether mitoquinone (MitoQ), a mitochondria-targeted antioxidant, could alleviate LPS-induced AEC damage in ALI and its underlying mechanisms. In vitro studies in AEC A549 cell line, we noted that LPS could induce dynamin-related protein 1 (Drp1)-mediated mitochondrial fission, AEC apoptosis and barrier breakdown, which could be reversed with MitoQ and mitochondrial division inhibitor 1 treatment. Moreover, the protective role of MitoQ was attenuated with Drp1 overexpression. Nuclear factor E2-related factor 2 (Nrf2) downregulation could block the effect of MitoQ by decreasing the expression of Nrf2 target genes in LPS-treated AEC, such as heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO1). Nrf2 gene knockdown in LPS-treated A549 cells prevented the protective effect of MitoQ from decreasing Drp1-mediated mitochondrial fission, AEC apoptosis and barrier breakdown. The lung protective effect of MitoQ by regulating the Drp1-mediated mitochondrial fission, AEC apoptosis and barrier breakdown was further confirmed in vivo with LPS-induced ALI mouse model. Additionally, the protective effect of MitoQ was inhibited by Nrf2 inhibitor ML385. We therefore conclude that MitoQ exerts ALI-protective effects by preventing Nrf2/Drp1-mediated mitochondrial fission, AEC apoptosis as well as barrier breakdown.

Dysiarenone from Marine Sponge Dysidea arenaria Attenuates ROS and Inflammation via Inhibition of 5-LOX/NF-κB/MAPKs and Upregulation of Nrf-2/OH-1 in RAW 264.7 Macrophages

Background

Marine natural products harbor a variety of pharmacological activities, and the sea species have been becoming a main source of new drug candidate. In pursuit of safer and more effective anti-inflammation drug, the anti-inflammatory activities, anti-oxygenation effects and underlying molecular mechanisms of compound dysiarenone from Dysidea arenaria were investigated via LPS-induced RAW 264.7 cell model.

Methods

Firstly, RAW 264.7 cells have been stimulated with LPS and treated with dysiarenone, and the cell viability of the LPS-treated RAW 264.7 cells was examined. One-step method, DCFH-DA fluorescence probe method was used to detect reactive oxygen species (ROS). The modulation of dysiarenone on anti-inflammation was detected by enzyme-linked immunosorbent assay by measuring the release of inflammatory cytokines (TNF-α and IL-6), and inflammatory mediators (LTB4). Further, the underlying anti-inflammatory mechanism of dysiarenone was explored by determining the expression of inducible 5-LOX, MAPKs, p-Akt, and p-NF-κB p65. Oxidative stress is tightly connected with inflammation, which was also evaluated through nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (OH-1) signaling pathway.

Results

Our study unraveled that dysiarenone between 2 and 8 µM reduces the inflammation responses via suppressing the production of inflammatory cytokines (TNF-α and IL-6) and inflammatory mediators (LTB₄). Dysiarenone down-regulated the protein levels of inducible 5-LOX via the inhibition of phosphorylation of MAPKs (including p38, ERK), Akt and NF-κB p65. Additionally, dysiarenone decreases ROS accumulation by upregulating HO-1 expression via nuclear translocation of Nrf2.

Conclusion

In conclusion, we demonstrated that dysiarenone possesses anti-inflammation and anti-oxidation activity via inhibiting 5-LOX/NF-κB/MAPK and Nrf2/HO-1 signaling pathway. Dysiarenone might be a promising lead compound for inflammatory diseases.

USP13 mediates PTEN to ameliorate osteoarthritis by restraining oxidative stress, apoptosis and inflammation via AKT-dependent manner

Osteoarthritis is a chronic, systemic and inflammatory disease. However, the pathogenesis and understanding of RA are still limited. Ubiquitin-specific protease 13 (USP13) belongs to the deubiquitinating enzyme (DUB) superfamily, and has been implicated in various cellular events. Nevertheless, its potential on RA progression has little to be investigated. In the present study, we found that USP13 expression was markedly up-regulated in synovial tissue samples from patients with RA, and was down-regulated in human fibroblast-like synoviocytes (H-FLSs) stimulated by interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α) or lipopolysaccharide (LPS). We then showed that over-expressing USP13 markedly suppressed inflammatory response, oxidative stress and apoptosis in H-FLSs upon IL-1β or TNF-α challenge, whereas USP13 knockdown exhibited detrimental effects. In addition, USP13-induced protective effects were associated with the improvement of nuclear factor erythroid 2-related factor 2 (Nrf-2) and the repression of Casapse-3. Furthermore, phosphatase and tensin homolog (PTEN) expression was greatly improved by USP13 in H-FLSs upon IL-1β or TNF-α treatment, whereas phosphorylated AKT expression was diminished. In response to IL-1β or TNF-α exposure, nuclear transcription factor κB (NF-κB) signaling pathway was activated, whereas being significantly restrained in H-FLSs over-expressing USP13. Mechanistically, USP13 directly interacted with PTEN. Of note, we found that USP13-regulated cellular processes including inflammation, oxidative stress and apoptotic cell death were partly dependent on AKT activation. Furthermore, USP13 over-expression effectively inhibited osteoclastogenesis and osteoclast-associated gene expression. The in vivo experiments finally confirmed that USP13 dramatically repressed synovial hyperplasia, inflammatory cell infiltration, cartilage damage and bone loss in collagen-induced arthritis (CIA) mice via the same molecular mechanisms detected in vitro. Taken together, these findings suggested that targeting USP13 may provide feasible therapies for RA.

Salvinorin A protects against methicillin resistant staphylococcus aureus-induced acute lung injury via Nrf2 pathway

Salvinorin A (SA), a neoclerodane diterpene, is isolated from the dried leaves ofSalvia divinorum. SA has traditionally been used treatments for chronic pain diseases. Recent research has demonstrated that SA possesses the anti-inflammatory property. The present study aim to explore the effects and potentialmechanisms ofSA in protection against Methicillin Resistant Staphylococcus aureus (MRSA)-induced acute lung injury (ALI). Here, we firstly found that verylowdosesof SA (50 μg/kg) could markedly decrease the infiltration of pulmonary neutrophils, mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) and then attenuated ALI cause by MRSA infection in mice. In vitro findings revealed that SA attenuated lipoteichoicacid-induced apoptosis, inflammation and oxidative stress in RAW264.7 cells. Mechanism research revealed that SA increased both mRNA levels and protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and up-regulated mRNA expression of its downstream genes (HO-1, Gclm, Trx-1, SOD1 and SOD2). Additionally, Nrf2 knockout mice abolished the inhibitory effect of SA on neutrophil accumulation and oxidative stress in MRSA-induced ALI. In conclusion, SA attenuates MRSA-induced ALI via Nrf2 signaling pathways.

Contrast-induced nephropathy and oxidative stress: mechanistic insights for better interventional approaches

Contrast-induced nephropathy (CIN) or contrast-induced acute kidney injury (CI-AKI) is an iatrogenic acute kidney injury observed after intravascular administration of contrast media for intravascular diagnostic procedures or therapeutic angiographic intervention. High risk patients including those with chronic kidney disease (CKD), diabetes mellitus with impaired renal function, congestive heart failure, intraarterial intervention, higher volume of contrast, volume depletion, old age, multiple myeloma, hypertension, and hyperuricemia had increased prevalence of CIN. Although CIN is reversible by itself, some patients suffer this condition without renal recovery leading to CKD or even end-stage renal disease which required long term renal replacement therapy. In addition, both CIN and CKD have been associated with increasing of mortality. Three pathophysiological mechanisms have been proposed including direct tubular toxicity, intrarenal vasoconstriction, and excessive production of reactive oxygen species (ROS), all of which lead to impaired renal function. Reports from basic and clinical studies showing potential preventive strategies for CIN pathophysiology including low- or iso-osmolar contrast media are summarized and discussed. In addition, reports on pharmacological interventions to reduce ROS and attenuate CIN are summarized, highlighting potential for use in clinical practice. Understanding this contributory mechanism could pave ways to improve therapeutic strategies in combating CIN.

Promotion of Mitochondrial Protection by Emodin in Methylglyoxal-Treated Human Neuroblastoma SH-SY5Y Cells: Involvement of the AMPK/Nrf2/HO-1 Axis

Mitochondrial dysfunction is part of the mechanism of several human diseases. This negative circumstance may be induced by certain toxicants, as methylglyoxal (MG). MG is a reactive dicarbonyl presenting both endogenous and exogenous sources and is also able to induce protein cross-linking and glycation. Emodin (EM; 1,3,8-trihydroxy-6-methylanthracene-9,10-dione; C₁₅H₁₀O₅) is a cytoprotective agent. Nonetheless, it was not previously demonstrated whether EM would be able to promote mitochondrial protection in cells challenged with MG. Therefore, we investigated here whether and how EM would prevent the MG-induced mitochondrial collapse in the human neuroblastoma SH-SY5Y cells. We found that a pretreatment (for 4 h) with EM at 40 μM prevented the MG-induced mitochondrial dysfunction (i.e., decreased activity of the complexes I and V, reduced adenosine triphosphate levels, and loss of mitochondrial membrane potential) in the SH-SY5Y cells. EM also prevented the redox impairment induced by MG in mitochondrial membranes. Inhibiting the adenosine monophosphate-activated protein kinase (AMPK) or silencing of the nuclear factor erythroid 2-related factor 2 (Nrf2), transcription factor abolished the EM-induced protection. Inhibition of heme oxygenase-1 (HO-1) also blocked the EM-induced mitochondrial protection. Therefore, EM protected the mitochondria by a mechanism dependent on the AMPK/Nrf2/HO-1 signaling pathway in MG-challenged SH-SY5Y cells.