Regulation of the Nrf2 Pathway by Glycogen Synthase Kinase-3β in MPP⁺-Induced Cell Damage

The redox-sensitive GSK3β is a key regulator of glomerular podocyte injury in type 2 diabetic kidney disease

Emerging evidence suggests that GSK3β, a redox-sensitive transducer downstream of insulin signaling, acts as a convergent point for myriad pathways implicated in kidney injury, repair, and regeneration. However, its role in diabetic kidney disease remains controversial. In cultured glomerular podocytes, exposure to a milieu of type 2 diabetes elicited prominent signs of podocyte injury and degeneration, marked by loss of homeostatic marker proteins like synaptopodin, actin cytoskeleton disruption, oxidative stress, apoptosis, and stress-induced premature senescence, as shown by increased staining for senescence-associated β-galactosidase activity, amplified formation of γH2AX foci, and elevated expression of mediators of senescence signaling, like p21 and p16INK4A. These degenerative changes coincided with GSK3β hyperactivity, as evidenced by GSK3β overexpression and reduced inhibitory phosphorylation of GSK3β, and were averted by tideglusib, a highly-selective small molecule inhibitor of GSK3β. In agreement, post-hoc analysis of a publicly-available glomerular transcriptomics dataset from patients with type 2 diabetic nephropathy revealed that the curated diabetic nephropathy-related gene set was enriched in high GSK3β expression group. Mechanistically, GSK3β-modulated nuclear factor Nrf2 signaling is involved in diabetic podocytopathy, because GSK3β knockdown reinforced Nrf2 antioxidant response and suppressed oxidative stress, resulting in an improvement in podocyte injury and senescence. Conversely, ectopic expression of the constitutively active mutant of GSK3β impaired Nrf2 antioxidant response and augmented oxidative stress, culminating in an exacerbated diabetic podocyte injury and senescence. Moreover, IRS-1 was found to be a cognate substrate of GSK3β for phosphorylation at IRS-1S332, which negatively regulates IRS-1 activity. GSK3β hyperactivity promoted IRS-1 phosphorylation, denoting a desensitized insulin signaling. Consistently, in vivo in db/db mice with diabetic nephropathy, GSK3β was hyperactive in glomerular podocytes, associated with IRS-1 hyperphosphorylation, impaired Nrf2 response and premature senescence. Our finding suggests that GSK3β is likely a novel therapeutic target for treating type 2 diabetic glomerular injury.

Nrf-2-dependent antioxidant and anti-inflammatory effects underlie the protective effect of esculeoside A against retinal damage in streptozotocin-induced diabetic rats

Esculeoside A (ESA) is a tomato-derived glycoside with antioxidant and anti-inflammatory properties. The protective effect of ESA against diabetic retinopathy is not well-investigated and was the core objective of this study. In addition, we tested if such protection involves the activation of Nrf2 signaling. Type 1 diabetes mellitus (T1DM) was induced in adult Wistar male rats by an intraperitoneal injection of streptozotocin (65 mg/kg). Non-diabetic and T1DM rats were divided into two subgroup groups given either the vehicle or ESA (100 mg)/kg. An additional T1DM group was given ESA (100 mg/kg) and an Nrf2 inhibitor (2 mg/kg) (n=8 rats/group). Treatments continued for 12 weeks. In this study, according to the histological features, ESA improved the structure of ganglionic cells and increased the number of cells of the inner nuclear and plexiform layers in the retinas of T1DM rats. Concomitantly, it reduced the retina levels of malondialdehyde (lipid peroxides), vascular endothelial growth factor, interleukin-6, tumor necrosis factor-α, Bax, and caspase-3. In the retinas of the control and diabetic rats, ESA boosted the levels of total glutathione, superoxide dismutase, heme-oxygenase-1, and Bcl2, reduced the mRNA levels of REDD1, and enhanced cytoplasmic and nuclear levels of Nrf2. However, ESA failed to alter the mRNA levels of Nrf2 and keap1, protein levels of keap1, plasma glucose, plasma insulin, serum triglycerides, cholesterol, and LDL-c in both the control and T1DM rats. In conclusion, ESA alleviates retinopathy in T1DM rats by suppressing REDD1-associated degradation and inhibiting the Nrf2/antioxidant axis.

Heteronemin promotes iron-dependent cell death in pancreatic cancer

The marine environment has been recognized as a prolific source of potent bioactive compounds with significant anticancer properties. Among these, heteronemin, a sesterterpenoid-type natural product, has shown promise. This study delves into the potential of heteronemin as a ferroptotic agent against pancreatic cancer, using the Panc-1 cell line as a model. The cytotoxic potential of heteronemin was assessed using cell viability assays. Furthermore, its effect on lipid peroxidation was determined spectrophotometrically, while the changes it induced in autophagy- and ferritin-related protein expressions were evaluated using immunoblotting techniques. Various cell-based tests were employed to scrutinize its anticancer efficacy. Heteronemin displayed a notable cytotoxic effect, reducing cell viability by 50% at a concentration of 55 nM. This cytotoxicity was discernibly linked to ferroptosis, as evidenced by the reversal of cell death upon treatment with the ferroptosis inhibitor, ferrostatin-1. Heteronemin treatment led to a marked increase in ferroptosis markers and malondialdehyde (MDA) levels. Conversely, the expression of glutathione peroxidase-4 (GPX4), a key anti-ferroptotic protein, was suppressed. Furthermore, significant modulations in the expression of ferritinophagy- and iron-related proteins such as Atg5, Atg7, FTL, STEAP3, and DMT-1 were evident post-treatment (p < 0.05). This study underscores the potential of heteronemin as a ferroptosis inducer in pancreatic cancer cells. Given its robust cytotoxicity, heteronemin emerges as a promising lead compound for further exploration in cancer therapeutics.

Therapeutic Potential Effect of Glycogen Synthase Kinase 3 Beta (GSK-3β) Inhibitors in Parkinson Disease: Exploring an Overlooked Avenue

Parkinson's disease (PD) is a progressive neurodegenerative disease of the brain due to degeneration of dopaminergic neurons in the substantia nigra (SN). Glycogen synthase kinase 3 beta (GSK-3β) is implicated in the pathogenesis of PD. Therefore, the purpose of the present review was to revise the mechanistic role of GSK-3β in PD neuropathology, and how GSK-3β inhibitors affect PD neuropathology. GSK-3 is a conserved threonine/serine kinase protein that is intricate in the regulation of cellular anabolic and catabolic pathways by modulating glycogen synthase. Over-expression of GSK-3β is also interconnected with the development of different neurodegenerative diseases. However, the underlying mechanism of GSK-3β in PD neuropathology is not fully clarified. Over-expression of GSK-3β induces the development of PD by triggering mitochondrial dysfunction and oxidative stress in the dopaminergic neurons of the SN. NF-κB and NLRP3 inflammasome are activated in response to dysregulated GSK-3β in PD leading to progressive neuronal injury. Higher expression of GSK-3β in the early stages of PD neuropathology might contribute to the reduction of neuroprotective brain-derived neurotrophic factor (BDNF). Thus, GSK-3β inhibitors may be effective in PD by reducing inflammatory and oxidative stress disorders which are associated with degeneration of dopaminergic in the SN.

Ischemia-reperfusion injury: molecular mechanisms and therapeutic targets

Ischemia-reperfusion (I/R) injury paradoxically occurs during reperfusion following ischemia, exacerbating the initial tissue damage. The limited understanding of the intricate mechanisms underlying I/R injury hinders the development of effective therapeutic interventions. The Wnt signaling pathway exhibits extensive crosstalk with various other pathways, forming a network system of signaling pathways involved in I/R injury. This review article elucidates the underlying mechanisms involved in Wnt signaling, as well as the complex interplay between Wnt and other pathways, including Notch, phosphatidylinositol 3-kinase/protein kinase B, transforming growth factor-β, nuclear factor kappa, bone morphogenetic protein, N-methyl-D-aspartic acid receptor-Ca2+-Activin A, Hippo-Yes-associated protein, toll-like receptor 4/toll-interleukine-1 receptor domain-containing adapter-inducing interferon-β, and hepatocyte growth factor/mesenchymal-epithelial transition factor. In particular, we delve into their respective contributions to key pathological processes, including apoptosis, the inflammatory response, oxidative stress, extracellular matrix remodeling, angiogenesis, cell hypertrophy, fibrosis, ferroptosis, neurogenesis, and blood-brain barrier damage during I/R injury. Our comprehensive analysis of the mechanisms involved in Wnt signaling during I/R reveals that activation of the canonical Wnt pathway promotes organ recovery, while activation of the non-canonical Wnt pathways exacerbates injury. Moreover, we explore novel therapeutic approaches based on these mechanistic findings, incorporating evidence from animal experiments, current standards, and clinical trials. The objective of this review is to provide deeper insights into the roles of Wnt and its crosstalk signaling pathways in I/R-mediated processes and organ dysfunction, to facilitate the development of innovative therapeutic agents for I/R injury.

Novel Insights on Ferroptosis Modulation as Potential Strategy for Cancer Treatment: When Nature Kills

Significance: The multifactorial nature of the mechanisms implicated in cancer development still represents a major issue for the success of established antitumor therapies. The discovery of ferroptosis, a novel form of programmed cell death distinct from apoptosis, along with the identification of the molecular pathways activated during its execution, has led to the uncovering of novel molecules characterized by ferroptosis-inducing properties. Recent advances: As of today, the ferroptosis-inducing properties of compounds derived from natural sources have been investigated and interesting findings have been reported both in vitro and in vivo. Critical Issues: Despite the efforts made so far, only a limited number of synthetic compounds have been identified as ferroptosis inducers, and their utilization is still limited to basic research. In this review, we analyzed the most important biochemical pathways involved in ferroptosis execution, with particular attention to the newest literature findings on canonical and non-canonical hallmarks, together with mechanisms of action of natural compounds identified as novel ferroptosis inducers. Compounds have been classified based on their chemical structure, and modulation of ferroptosis-related biochemical pathways has been reported. Future Directions: The outcomes herein collected represent a fascinating starting point from which to take hints for future drug discovery studies aimed at identifying ferroptosis-inducing natural compounds for anticancer therapies. Antioxid. Redox Signal. 40, 40-85.

Overview on the Polyphenol Avenanthramide in Oats (Avena sativa Linn.) as Regulators of PI3K Signaling in the Management of Neurodegenerative Diseases

Avenanthramides (Avns) and their derivatives, a group of polyphenolic compounds found abundantly in oats (Avena sativa Linn.), have emerged as promising candidates for neuroprotection due to their immense antioxidant, anti-inflammatory, and anti-apoptotic properties. Neurodegenerative diseases (NDDs), characterized by the progressive degeneration of neurons, present a significant global health burden with limited therapeutic options. The phosphoinositide 3-kinase (PI3K) signaling pathway plays a crucial role in cell survival, growth, and metabolism, making it an attractive target for therapeutic intervention. The dysregulation of PI3K signaling has been implicated in the pathogenesis of various NDDs including Alzheimer's and Parkinson's disease. Avns have been shown to modulate PI3K/AKT signaling, leading to increased neuronal survival, reduced oxidative stress, and improved cognitive function. This review explores the potential of Avn polyphenols as modulators of the PI3K signaling pathway, focusing on their beneficial effects against NDDs. Further, we outline the need for clinical exploration to elucidate the specific mechanisms of Avn action on the PI3K/AKT pathway and its potential interactions with other signaling cascades involved in neurodegeneration. Based on the available literature, using relevant keywords from Google Scholar, PubMed, Scopus, Science Direct, and Web of Science, our review emphasizes the potential of using Avns as a therapeutic strategy for NDDs and warrants further investigation and clinical exploration.

Alkaloids as Natural NRF2 Inhibitors: Chemoprevention and Cytotoxic Action in Cancer

Being a controller of cytoprotective actions, inflammation, and mitochondrial function through participating in the regulation of multiple genes in response to stress-inducing endogenous or exogenous stressors, the transcription factor Nuclear Factor Erythroid 2-Related Factor 2 (NRF2) is considered the main cellular defense mechanism to maintain redox balance at cellular and tissue level. While a transient activation of NRF2 protects normal cells under oxidative stress, the hyperactivation of NRF2 in cancer cells may help them to survive and to adapt under oxidative stress. This can be detrimental and related to cancer progression and chemotherapy resistance. Therefore, inhibition of NRF2 activity may be an effective approach for sensitizing cancer cells to anticancer therapy. In this review, we examine alkaloids as NRF2 inhibitors from natural origin, their effects on cancer therapy, and/or as sensitizers of cancer cells to anticancer chemotherapeutics, and their potential clinical applications. Alkaloids, as inhibitor of the NRF2/KEAP1 signaling pathway, can have direct (berberine, evodiamine, and diterpenic aconitine types of alkaloids) or indirect (trigonelline) therapeutic/preventive effects. The network linking alkaloid action with oxidative stress and NRF2 modulation may result in an increased NRF2 synthesis, nuclear translocation, as well in a downstream impact on the synthesis of endogenous antioxidants, effects strongly presumed to be the mechanism of action of alkaloids in inducing cancer cell death or promoting sensitivity of cancer cells to chemotherapeutic agents. In this regard, the identification of additional alkaloids targeting the NRF2 pathway is desirable and the information arising from clinical trials will reveal the potential of these compounds as a promising target for anticancer therapy.

Junction of the redox dynamic, orchestra of signaling, and altered metabolism in regulation of T- cell lymphoma

T-cell lymphoma is a hematologic neoplasm derived from the lymphoid lineage. It belongs to a diverse group of malignant disorders, mostly affecting the young population worldwide, that vary with respect to molecular features as well as genetic and clinical complexities. Cancer cells rewire the cellular metabolism, persuading it to meet new demands of growth and proliferation. Furthermore, the metabolic alterations and heterogeneity are aberrantly driven in cancer by a combination of genetic and non-genetic factors, including the tumor microenvironment. New insight into cancer metabolism highlights the importance of nutrient supply to tumor development and therapeutic responses. Importantly, oxidative stress due to an imbalance in the redox status of reactive species via exogenous and/or endogenous factors is closely related to multiple aspects of cancer. This alters the signaling pathways governed through the multiple intracellular signal transduction and transcription factors, leading to tumor progression. These oncogenic signaling molecules are regulated through different redox sensors, including nuclear factor-erythroid 2 related factor 2 (Nrf2), phase-II antioxidant enzyme, and NQO1 (NADPH quinone oxidoreductase (1). The existing understanding of the molecular mechanisms of T-cell lymphoma regulation through the cross-talk of redox sensors under the influence of metabolic vulnerability is not well explored. This review highlights the role of the redox dynamics, orchestra of signaling, and genetic regulation involved in T-cell lymphoma progression in addition to the challenges to their etiology, treatment, and clinical response in light of recent updates.

Allii Macrostemonis Bulbus: A Comprehensive Review of Ethnopharmacology, Phytochemistry and Pharmacology

The dried bulbs of Allii Macrostemonis Bulbus (AMB) are called “薤白” in China and are mainly distributed in Asia. The plant species included in the 2020 Edition of the Chinese Pharmacopoeia (ChP) are Allium macrostemon Bunge (called xiaogensuan in Chinese, A. macrostemon) and Allium chinense G. Don (called xie in Chinese, A. chinense), respectively. In the traditional Chinese medicine (TCM) theoretical system, AMB is warm in nature, acrid-bitter taste, and attributive to the heart, lung, stomach, large intestine meridian. AMB has the function of activating Yang and removing stasis, regulating Qi and eliminating stagnation. Modern pharmacological studies have shown that AMB has anti-platelet aggregation, hypolipidemic, anti-atherosclerotic, cardiomyocyte, vascular endothelial cell protection, anti-cancer, anti-bacterial, anti-asthmatic, and anti-oxidant effects. In some Asian countries, AMB is often used to treat coronary heart disease (CHD), angina pectoris (AP), asthma, and diarrhea. This review collates the botanical background, ethnopharmacology, phytochemistry, pharmacological activities, quality control, and toxicological studies of AMB, and provides an outlook on the current research deficiencies and future research priorities of AMB, intending to provide ideas for future research directions and commercial development.

Peroxiredoxins and Hypoxia-Inducible Factor-1α in Duodenal Tissue: Emerging Factors in the Pathophysiology of Pediatric Celiac Disease Patients

Celiac disease (CD) is an autoimmune enteropathy. Peroxiredoxins (PRDXs) are powerful antioxidant enzymes having an important role in significant cellular pathways including cell survival, apoptosis, and inflammation. This study aimed at investigating the expression levels of all PRDX isoforms (1-6) and their possible relationships with a transcription factor, HIF-1α, in the small intestinal tissue samples of pediatric CD patients. The study groups consisted of first-diagnosed CD patients (n = 7) and non-CD patients with functional gastrointestinal tract disorders as the controls (n = 7). The PRDXs and HIF-1α expression levels were determined by using real-time PCR and Western blotting in duodenal biopsy samples. It was observed that the mRNA and protein expression levels of PRDX 5 were significantly higher in the CD patients, whereas the PRDX 1, -2, and -4 expressions were decreased in each case compared to the control group. No significant differences were detected in the PRDX 3 and PRDX 6 expressions. The expression of HIF-1α was also significantly elevated in CD patients. These findings indicate, for the first time, that PRDXs, particularly PRDX 5, may play a significant role in the pathogenesis of CD. Furthermore, our results suggest that HIF-1α may upregulate PRDX-5 transcription in the duodenal tissue of CD.

Role of Nrf2 in aging, Alzheimer's and other neurodegenerative diseases

Nuclear Factor-Erythroid Factor 2 (Nrf2) is an important transcription factor that regulates the expression of large number of genes in healthy and disease states. Nrf2 is made up of 605 amino acids and contains 7 conserved regions known as Nrf2-ECH homology domains. Nrf2 regulates the expression of several key components of oxidative stress, mitochondrial biogenesis, mitophagy, autophagy and mitochondrial function in all organs of the human body, in the peripheral and central nervous systems. Mounting evidence also suggests that altered expression of Nrf2 is largely involved in aging, neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's diseases, Amyotrophic lateral sclerosis, Stroke, Multiple sclerosis and others. The purpose of this article is to detail the essential role of Nrf2 in oxidative stress, antioxidative defense, detoxification, inflammatory responses, transcription factors, proteasomal and autophagic/mitophagic degradation, and metabolism in aging and neurodegenerative diseases. This article also highlights the Nrf2 structural and functional activities in healthy and disease states, and also discusses the current status of Nrf2 research and therapeutic strategies to treat aging and neurodegenerative diseases.

GSK-3β-mediated regulation of Nrf2/HO-1 signaling as a new therapeutic approach in the treatment of movement disorders

Movement disorders are neurological conditions characterized by involuntary motor movements, such as dystonia, ataxia, chorea myoclonus, tremors, Huntington's disease (HD), and Parkinson's disease (PD). It is classified into two categories: hypokinetic and hyperkinetic movements. Globally, movement disorders are a major cause of death. The pathophysiological process is initiated by excessive ROS generation, mitochondrial dysfunction, neuroinflammation, and neurotransmitters imbalance that lead to motor dysfunction in PD and HD patients. Several endogenous targets including Nrf2 maintain oxidative balance in the body. Activation of Nrf2 signaling is regulated by the enzyme glycogen synthase kinase (GSK-3β). In the cytoplasm, inhibition of GSK-3β regulates cellular proliferation, homeostasis, and apoptotic process by stimulating the nuclear factor erythroid 2 (Nrf2) pathway which is involved in the elevation of the cellular antioxidant enzymes which controls the ROS generation. The activation of Nrf2 increases the expression of antioxidant response elements (ARE), such as (Hemeoxygenase-1) HO-1, which decreases excessive cellular stress, mitochondrial dysfunction, apoptosis, and neuronal degeneration, which is the major cause of motor dysfunction. The present review explores the GSK-3β-mediated neuroprotection in various movement disorders through the Nrf2/HO-1 antioxidant pathway. This review provides a link between GSK-3β and the Nrf2/HO-1 signaling pathway in the treatment of PD and HD. In addition to that it highlights various GSK-3β inhibitors and the Nrf2/HO-1 activators, which exert robust neuroprotection against motor disorders. Therefore, the present review will help in the discovery of new therapy for PD and HD patients.

Targeting NLRP3 Inflammasome With Nrf2 Inducers in Central Nervous System Disorders

The NLRP3 inflammasome is an intracellular multiprotein complex that plays an essential role in the innate immune system by identifying and eliminating a plethora of endogenous and exogenous threats to the host. Upon activation of the NLRP3 complex, pro-inflammatory cytokines are processed and released. Furthermore, activation of the NLRP3 inflammasome complex can induce pyroptotic cell death, thereby propagating the inflammatory response. The aberrant activity and detrimental effects of NLRP3 inflammasome activation have been associated with cardiovascular, neurodegenerative, metabolic, and inflammatory diseases. Therefore, clinical strategies targeting the inhibition of the self-propelled NLRP3 inflammasome activation are required. The transcription factor Nrf2 regulates cellular stress response, controlling the redox equilibrium, metabolic programming, and inflammation. The Nrf2 pathway participates in anti-oxidative, cytoprotective, and anti-inflammatory activities. This prominent regulator, through pharmacologic activation, could provide a therapeutic strategy for the diseases to the etiology and pathogenesis of which NLRP3 inflammasome contributes. In this review, current knowledge on NLRP3 inflammasome activation and Nrf2 pathways is presented; the relationship between NLRP3 inflammasome signaling and Nrf2 pathway, as well as the pre/clinical use of Nrf2 activators against NLRP3 inflammasome activation in disorders of the central nervous system, are thoroughly described. Cumulative evidence points out therapeutic use of Nrf2 activators against NLRP3 inflammasome activation or diseases that NLRP3 inflammasome contributes to would be advantageous to prevent inflammatory conditions; however, the side effects of these molecules should be kept in mind before applying them to clinical practice.

Tideglusib Ameliorates Ischemia/Reperfusion Damage by Inhibiting GSK-3β and Apoptosis in Rat Model of Ischemic Stroke

OBJECTIVES

Glycogen synthase kinase-3β (GSK-3β), a serine/threonine protein kinase, gets activated and worsen stroke outcome after ischemia/reperfusion (I/R) injury by inducing inflammation and apoptosis. In this study, tideglusib, a selective irreversible and non-ATP competitive inhibitor of GSK-3β, was explored in cerebral I/R damage using middle cerebral artery occlusion (MCAo) model in rats.

MATERIALS AND METHODS

MCAo was done for 90 min in male Wistar rats (250-280 g) using doccol suture. In pre-treatment group, tideglusib (50 mg/kg) was administered once daily for 2 days and on the day of surgery, 30 min before MCAo. Next day, rats were examined for neurobehavioral parameters and MRI was performed to assess brain damage. In post-treatment group, tideglusib was started at 30 min after MCAo and continued for the next 2 days. After 72 h of MCAo, behavioral parameters and brain damage by MRI were assessed. Further, oxidative stress markers (MDA and GSH), inflammatory cytokines (TNF-α, IL-1β and IL-10) and expression levels of pGSK-3β S9, Bcl-2 and Bax were estimated in pre-treatment group.

RESULTS

Tideglusib pre-treatment but not post-treatment significantly improved neurobehavioral parameters (p < 0.05) and reduced brain damage (p < 0.01) when compared with MCAo group. I/R induced changes in MDA (p < 0.01), TNF-α and IL-1β (p < 0.05) were significantly attenuated by pre-treatment. Further, tideglusib pre-treatment ameliorated MCAo induced altered expressions of pGSK-3β S9, Bcl-2 and Bax.

CONCLUSION

The results of our exploratory study indicated prophylactic potential of tideglusib in I/R injury by modulating pGSK-3β S9, apoptosis and neuro-inflammation.

The combination of ultrafine carbon black and lead provokes cytotoxicity and apoptosis in mice lung fibroblasts through oxidative stress-activated mitochondrial pathways

Ultrafine particulates (UFPs) are considered one of the most hazardous of all air pollutants, which can be directly inhaled into the human body and cause direct damage to lung tissues. Lung fibroblasts (LF) play an important role in the structure and function of lung and there are few studies on primary cells at present. So, the article focuses on LF as the research objective and ultrafine carbon black (UFCB) and Pb-UFCB (loaded with lead) as a representative of UFPs to study the effect on LF. The results showed that UFCB and Pb-UFCB inhibited LF proliferation due to cell cycle arrested in the S phase, and induced apoptosis. Additionally, UFCB or Pb-UFCB could induce oxidative stress manifested as the increase of intracellular reactive oxygen species. The redox imbalance was further confirmed by measuring the changes of related enzymes, including the activity of superoxide dismutase and catalase and the level of reduced glutathione and malondialdehyde in cells. Moreover, the elevated lactate dehydrogenase in the culture medium indicated that cell membrane had been injured. And mitochondrial function was impaired by the imbalance of ATP synthesis and hydrolysis. In summary, both induced oxidative stress, which is the main driving force of LF early apoptosis, disruption of cell membrane integrity and mitochondrial function. Here, we provide a meaningful and challenging subject to explore the toxic effect and mechanism between UFPs and lung tissue at cellular levels, and theoretical basics for the possible changes of lung tissue function in vivo.

Insulin-like growth factor II prevents oxidative and neuronal damage in cellular and mice models of Parkinson's disease

Oxidative distress and mitochondrial dysfunction, are key factors involved in the pathophysiology of Parkinson's disease (PD). The pleiotropic hormone insulin-like growth factor II (IGF-II) has shown neuroprotective and antioxidant effects in some neurodegenerative diseases. In this work, we demonstrate the protective effect of IGF-II against the damage induced by 1-methyl-4-phenylpyridinium (MPP+) in neuronal dopaminergic cell cultures and a mouse model of progressive PD. In the neuronal model, IGF-II counteracts the oxidative distress produced by MPP + protecting dopaminergic neurons. Improved mitochondrial function, increased nuclear factor (erythroid-derived 2)-like2 (NRF2) nuclear translocation along with NRF2-dependent upregulation of antioxidative enzymes, and modulation of mammalian target of rapamycin (mTOR) signalling pathway were identified as mechanisms leading to neuroprotection and the survival of dopaminergic cells. The neuroprotective effect of IGF-II against MPP + -neurotoxicity on dopaminergic neurons depends on the specific IGF-II receptor (IGF-IIr). In the mouse model, IGF-II prevents behavioural dysfunction and dopaminergic nigrostriatal pathway degeneration and mitigates neuroinflammation induced by MPP+. Our work demonstrates that hampering oxidative stress and normalising mitochondrial function through the interaction of IGF-II with its specific IGF-IIr are neuroprotective in both neuronal and mouse models. Thus, the modulation of the IGF-II/IGF-IIr signalling pathway may be a useful therapeutic approach for the prevention and treatment of PD.

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IGF-II hampers oxidative damage and promotes survival in a cellular model of PD.

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IGF-II avoids mitochondrial damage in dopaminergic cells in a model of PD.

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IGF-II receptor mediates the neuroprotective effect of IGF-II in a cellular model of PD.

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IGF-II prevents nigrostriatal degeneration and inflammation in a mice model of PD.

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IGF-II prevents behavioural dysfunction in a mice model of PD.

Multifunctional Ligands with Glycogen Synthase Kinase 3 Inhibitory Activity as a New Direction in Drug Research for Alzheimer's Disease

Alzheimer's disease (AD) belongs to the most common forms of dementia that causes a progressive loss of brain cells and leads to memory impairment and decline of other thinking skills. There is yet no effective treatment for AD; hence, the search for new drugs that could improve memory and other cognitive functions is one of the hot research topics worldwide. Scientific efforts are also directed toward combating behavioral and psychological symptoms of dementia, which are an integral part of the disease. Several studies have indicated that glycogen synthase kinase 3 beta (GSK3β) plays a crucial role in the pathogenesis of AD. Moreover, GSK3β inhibition provided beneficial effects on memory improvement in multiple animal models of AD. The present review aimed to update the most recent reports on the discovery of novel multifunctional ligands with GSK3β inhibitory activity as potential drugs for the symptomatic and disease-modifying therapy of AD. Compounds with GSK3β inhibitory activity seem to be an effective pharmacological approach for treating the causes and symptoms of AD as they reduced neuroinflammation and pathological hallmarks in animal models of AD and provided relief from cognitive and neuropsychiatric symptoms. These compounds have the potential to be used as drugs for the treatment of AD, but their precise pharmacological, pharmacokinetic, toxicological and clinical profiles need to be defined.

The Role of Nrf2 and PPARγ in the Improvement of Oxidative Stress in Hypertension and Cardiovascular Diseases

Reactive oxygen species are an important element of redox regulation in cells and tissues. During physiological processes, molecules undergo chemical changes caused by reduction and oxidation reactions. Free radicals are involved in interactions with other molecules, leading to oxidative stress. Oxidative stress works two ways depending on the levels of oxidizing agents and products. Excessive action of oxidizing agents damages biomolecules, while a moderate physiological level of oxidative stress (oxidative eustress) is necessary to control life processes through redox signaling required for normal cellular operation. High levels of reactive oxygen species (ROS) mediate pathological changes. Oxidative stress helps to regulate cellular phenotypes in physiological and pathological conditions. Nrf2 (nuclear factor erythroid 2-related factor 2, NFE2L2) transcription factor functions as a target nuclear receptor against oxidative stress and is a key factor in redox regulation in hypertension and cardiovascular disease. Nrf2 mediates transcriptional regulation of a variety of target genes. The Keap1-Nrf2-ARE system regulates many detoxification and antioxidant enzymes in cells after the exposure to reactive oxygen species and electrophiles. Activation of Nrf2/ARE signaling is differentially regulated during acute and chronic stress. Keap1 normally maintains Nrf2 in the cytosol and stimulates its degradation through ubiquitination. During acute oxidative stress, oxidized molecules modify the interaction of Nrf2 and Keap1, when Nrf2 is released from the cytoplasm into the nucleus where it binds to the antioxidant response element (ARE). This triggers the expression of antioxidant and detoxification genes. The consequence of long-term chronic oxidative stress is activation of glycogen synthase kinase 3β (GSK-3β) inhibiting Nrf2 activity and function. PPARγ (peroxisome proliferator-activated receptor gamma) is a nuclear receptor playing an important role in the management of cardiovascular diseases, hypertension and metabolic syndrome. PPARγ targeting of genes with peroxisome proliferator response element (PPRE) has led to the identification of several genes involved in lipid metabolism or oxidative stress. PPARγ stimulation is triggered by endogenous and exogenous ligands – agonists and it is involved in the activation of several cellular signaling pathways involved in oxidative stress response, such as the PI3K/Akt/NOS pathway. Nrf2 and PPARγ are linked together with their several activators and Nrf2/ARE and PPARγ/PPRE pathways can control several types of diseases.

Hepatoprotective effect of rebamipide against methotrexate-induced hepatic intoxication: role of Nrf2/GSK-3β, NF-κβ-p65/JAK1/STAT3, and PUMA/Bax/Bcl-2 signaling pathways

OBJECTIVES

The fact that methotrexate (MTX) is hepatotoxic is an important reason to limit its clinical use. Rebamipide (REB) has antioxidant and anti-inflammatory properties and is useful for the treatment of gastro-duodenal ulcers. This study investigated the impact and protective mechanisms of REB against MTX-induced hepatotoxicity in rats.

MATERIALS AND METHODS

Animals were divided into four groups of six rats each: a control group, REB group (REB 100 mg/kg/day, orally), MTX control group (20 mg/kg, single i.p.), and MTX + REB group.

RESULTS

The administration of MTX induced marked hepatic injury in the form of hepatocyte inflammatory swelling, degeneration, apoptosis, and focal necrosis. In parallel, our biochemical investigations revealed a marked hepatic dysfunction associated with the disturbance of the oxidant/antioxidant balance in the group treated with only MTX. Moreover, MTX led to the down-regulation of the hepatic Nrf2 and Bcl-2 expressions along with a marked elevation in the hepatic NF-κβ-p65, GSK-3β, JAK1, STAT3, PUMA, and Bax expressions. On the other hand, co-treatment with REB significantly ameliorated the aforementioned histopathological, biochemical, and molecular defects caused by MTX treatment.

CONCLUSION

the outcomes of the present study showed REB's ability to protect from hepatic injury induced by MTX, possibly through its antioxidant, anti-inflammatory, and anti-apoptotic properties. These effects could be attributed to REB's ability to modulate, at least in part, the Nrf2/GSK-3β,NF-κβ-p65/JAK1/STAT3, and PUMA/Bax/Bcl-2signaling pathways.

Regulation of GSK3β/Nrf2 signaling pathway modulated erastin-induced ferroptosis in breast cancer

Ferroptosis is a newly discovered form of regulated cell death and characterized by an iron-dependent accumulation of lethal lipid reactive oxygen species (ROS), ferroptosis may exhibit a novel spectrum of clinical activity for cancer therapy. However, the significance of ferroptosis in the context of carcinoma biology is still emerging. Glycogen synthase kinase-3β (GSK-3β) has been found to be a fundamental element in weaking antioxidant cell defense by adjusting the nuclear factor erythroid 2-related factor 2 (Nrf2). In our study, decreased expression of GSK-3β was observed in the cancer tissues of breast cancer patients, results of immunohistochemistry indicated that Nrf2 was highly expressed in low-GSK-3β-expressed breast cancer tissues. The contributions of aberrant expression of GSK-3β and Nrf2 to the erastin-induced ferroptosis in breast cancer were further assessed, silence of GSK-3β blocked erastin-induced ferroptosis with less production of ROS and malondialdehyde (MDA) via upregulation of GPX4 and downregulation of arachidonate 15-lipoxygenase (Alox15), overexpression of GSK-3β enhanced erastin-triggered ferroptosis with elevated ROS and MDA. Enhanced erastin-induced ferroptosis by overexpression of GSK-3β was blocked by activating Nrf2. We further confirmed that overexpression of GSK-3β strengthened erastin-induced tumor growth inhibition in breast cancer xenograft models in vivo. In summary, our findings conclude that modulation the balance between GSK-3β/Nrf2 is a promising therapeutic approach and probably will be important targets to enhance the effect of erastin-induced ferroptosis in breast cancer.

Modulated Expression of the Protein Kinase GSK3 in Motor and Dopaminergic Neurons Increases Female Lifespan in Drosophila melanogaster

Most eukaryotic genes express multiple transcripts and proteins, and a sophisticated gene expression strategy plays a crucial role in ensuring the cell-specificity of genetic information and the correctness of phenotypes. The Drosophila melanogaster gene shaggy encodes several isoforms of the conserved glycogen synthase kinase 3 (GSK3), which is vitally important for multiple biological processes. To characterize the phenotypic effects of differential shaggy expression, we explored how the multidirectional modulation of the expression of the main GSK3 isoform, Shaggy-PB, in different tissues and cells affects lifespan. To this end, we used lines with transgenic constructs that encode mutant variants of the protein. The effect of shaggy misexpression on lifespan depended on the direction of the presumed change in GSK3 activity and the type of tissue/cell. The modulation of GSK3 activity in motor and dopaminergic neurons improved female lifespan but caused seemingly negative changes in the structural (mitochondrial depletion; neuronal loss) and functional (perturbed locomotion) properties of the nervous system, indicating the importance of analyzing the relationship between lifespan and healthspan in invertebrate models. Our findings provide new insights into the molecular and cellular bases of lifespan extension, demonstrating that the fine-tuning of transcript-specific shaggy expression in individual groups of neurons is sufficient to provide a sex-specific increase in survival and slow aging.

NRF2 Regulation Processes as a Source of Potential Drug Targets against Neurodegenerative Diseases

NRF2 acts by controlling gene expression, being the master regulator of the Phase II antioxidant response, and also being key to the control of neuroinflammation. NRF2 activity is regulated at several levels, including protein degradation by the proteasome, transcription, and post-transcription. The purpose of this review is to offer a concise and critical overview of the main mechanisms of NRF2 regulation and their actual or potential use as targets for the treatment of neurodegenerative diseases.

GSK-3β Contributes to Parkinsonian Dopaminergic Neuron Death: Evidence From Conditional Knockout Mice and Tideglusib

Glycogen synthase kinase-3 (GSK-3) dysregulation has been implicated in nigral dopaminergic neurodegeneration, one of the main pathological features of Parkinson’s disease (PD). The two isoforms, GSK-3α and GSK-3β, have both been suggested to play a detrimental role in neuronal death. To date, several studies have focused on the role of GSK-3β on PD pathogenesis, while the role of GSK-3α has been largely overlooked. Here, we report in situ observations that both GSK-3α and GSK-3β are dephosphorylated at a negatively acting regulatory serine, indicating kinase activation, selectively in nigral dopaminergic neurons following exposure of mice to 1-methyl-4-pheny-1,2,3,6-tetrahydropyridine (MPTP). To identify whether GSK-3α and GSK-3β display functional redundancy in regulating parkinsonian dopaminergic cell death, we analysed dopaminergic neuron-specific Gsk3a null (Gsk3a^ΔDat) and Gsk3b null (Gsk3b^ΔDat) mice, respectively. We found that Gsk3b^ΔDat, but not Gsk3a^ΔDat, showed significant resistance to MPTP insult, revealing non-redundancy of GSK-3α and GSK-3β in PD pathogenesis. In addition, we tested the neuroprotective effect of tideglusib, the most clinically advanced inhibitor of GSK-3, in the MPTP model of PD. Administration of higher doses (200 mg/kg and 500 mg/kg) of tideglusib exhibited significant neuroprotection, whereas 50 mg/kg tideglusib failed to prevent dopaminergic neurodegeneration from MPTP toxicity. Administration of 200 mg/kg tideglusib improved motor symptoms of MPTP-treated mice. Together, these data demonstrate GSK-3β and not GSK-3α is critical for parkinsonian neurodegeneration. Our data support the view that GSK-3β acts as a potential therapeutic target in PD and tideglusib would be a candidate drug for PD neuroprotective therapy.

Pioglitazone Attenuates Lipopolysaccharide-Induced Oxidative Stress, Dopaminergic Neuronal Loss and Neurobehavioral Impairment by Activating Nrf2/ARE/HO-1

The aim of the present study was to examine the neuroprotective potential of pioglitazone via activation of Nrf2/ARE-dependent HO-1 signaling pathway in chronic neuroinflammation and progressive neurodegeneration mouse model induced by lipopolysaccharide (LPS). After assessing spatial memory, anxiety and motor-coordination, TH+ neurons in substantia nigra (SN) were counted. The oxidative stress marker carbonyl protein levels and HO-1 enzyme activity were also evaluated. RT-qPCR was conducted to detect HO-1, Nrf2 and NF-κp65 mRNA expression levels and Nrf2 transcriptional activation of antioxidant response element (ARE) of HO-1 was investigated. Pioglitazone ameliorated LPS-induced dopaminergic neuronal loss, as well as mitigated neurobehavioral impairments. It enhanced Nrf2 mRNA expression, and augmented Nrf2/ARE-dependent HO-1 pathway activation by amplifying HO-1 mRNA expression. Moreover, it induced a significant decrease in NF-κB p65 mRNA expression, while reducing carbonyl protein levels and restoring the HO-1 enzyme activity. Interestingly, LPS induced Nrf2/antioxidant response element (ARE) of HO-1 activation, ultimately resulting in slight enhanced HO-1 mRNA expression. However, LPS elicited decrease in HO-1 enzyme activity. Zinc protoporphyrin-IX (ZnPPIX) administrated with pioglitazone abolished its effects in the LPS mouse model. The study results demonstrate that coordinated activation of Nrf2/ARE-dependent HO-1 pathway defense mechanism by the PPARγ agonist pioglitazone mediated its neuroprotective effects.