Dehydroepiandrosterone alleviates oxidative stress and apoptosis in iron-induced epilepsy via activation of Nrf2/ARE signal pathway

Impact of NQO1 dysregulation in CNS disorders

NAD(P)H Quinone Dehydrogenase 1 (NQO1) plays a pivotal role in the regulation of neuronal function and synaptic plasticity, cellular adaptation to oxidative stress, neuroinflammatory and degenerative processes, and tumorigenesis in the central nervous system (CNS). Impairment of the NQO1 activity in the CNS can result in abnormal neurotransmitter release and clearance, increased oxidative stress, and aggravated cellular injury/death. Furthermore, it can cause disturbances in neural circuit function and synaptic neurotransmission. The abnormalities of NQO1 enzyme activity have been linked to the pathophysiological mechanisms of multiple neurological disorders, including Parkinson's disease, Alzheimer's disease, epilepsy, multiple sclerosis, cerebrovascular disease, traumatic brain injury, and brain malignancy. NQO1 contributes to various dimensions of tumorigenesis and treatment response in various brain tumors. The precise mechanisms through which abnormalities in NQO1 function contribute to these neurological disorders continue to be a subject of ongoing research. Building upon the existing knowledge, the present study reviews current investigations describing the role of NQO1 dysregulations in various neurological disorders. This study emphasizes the potential of NQO1 as a biomarker in diagnostic and prognostic approaches, as well as its suitability as a target for drug development strategies in neurological disorders.

Disorders of the central nervous system: Insights from Notch and Nrf2 signaling

The functional complexity of the central nervous system (CNS) is unparalleled in living organisms. It arises from neural crest-derived cells that migrate by the exact route, leading to the formation of a complex network of neurons and glial cells. Recent studies have shown that novel crosstalk exists between the Notch1 and Nrf2 pathways and is associated with many neurological diseases. The Notch1-Nrf2 axis may act on nervous system development, and the molecular mechanism has recently been reported. In this review, we summarize the essential structure and function of the CNS. The significance of interactions between signaling pathways and between developmental processes like proliferation, apoptosis and migration in ensuring the correct development of the CNS is also presented. We primarily focus on research concerning possible mechanism of interaction between Notch1 and Nrf2 and the functions of Notch1-Nrf2 in neurons. There may be a direct interaction between Notch1 and NRF2, which is closely related to the crosstalk that occurs between them. The significance and potential applications of the Notch1-Nrf2 axis in abnormal development of the nervous system are been highlighten. We also discuss the molecular mechanisms by which the Notch1-Nrf2 axis controls the apoptosis, antioxidant pathway and differentiation of neurons to modulate the development of the nervous system. This information will lead to a better understanding of Notch1-Nrf2 axis signaling pathways in the nervous system and may facilitate the development of new therapeutic strategies.

Sexually dimorphic metal alterations in childhood obesity are modulated by a complex interplay between inflammation, insulin, and sex hormones

Although growing evidence points to a pivotal role of perturbed metal homeostasis in childhood obesity, sexual dimorphisms in this association have rarely been investigated. In this study, we applied multi-elemental analysis to plasma and erythrocyte samples from an observational cohort comprising children with obesity, with and without insulin resistance, and healthy control children. Furthermore, a wide number of variables related to carbohydrate and lipid metabolism, inflammation, and sex hormones were also determined. Children with obesity, regardless of sex and insulin resistance status, showed increased plasma copper-to-zinc ratios. More interestingly, obesity-related erythroid alterations were found to be sex-dependent, with increased contents of iron, zinc, and copper being exclusively detected among female subjects. Our findings suggest that a sexually dimorphic hormonal dysregulation in response to a pathological cascade involving inflammatory processes and hyperinsulinemia could be the main trigger of this female-specific intracellular sequestration of trace elements. Therefore, the present study highlights the relevance of genotypic sex as a susceptibility factor influencing the pathogenic events behind childhood obesity, thereby opening the door to develop sex-personalized approaches in the context of precision medicine.

The increase of Nrf2 m6A modification induced by FTO downregulation promotes hippocampal neuron injury and aggravates the progression of epilepsy in a rat model

Epilepsy is a common chronic neurological disorder characterized by widespread neuronal death. The purpose of this study was to investigate the role of nuclear factor erythroid 2-related factor 2 (Nrf2) m6A methylation in epilepsy. To create epileptic models, the rats were given Lithium chloride and pilocarpine, and isolated primary rat hippocampal neurons were cultured in an Mg2⁺ -free medium. The frequency of seizures was recorded in the epilepsy group of rats. The functional tests included TUNEL, MTT, and flow cytometry. Mechanistically, RNA degradation assay, RNA immunoprecipitation, and methylated RNA immunoprecipitation were performed. In epileptic models, Nrf2 and fat mass and obesity-associated (FTO) levels were downregulated, whereas YT521-B homology (YTH) domain family protein 2 (YTHDF2) was upregulated. Additionally, in epileptic models, there was a rise in the m6A methylation level of Nrf2 mRNA. Overexpressing FTO increased cell viability and reduced apoptosis, but Nrf2 interference reversed these effects. Meanwhile, FTO overexpression decreased the m6A methylation of Nrf2 mRNA. Moreover, YTHDF2 bound to Nrf2 mRNA and decreased its stability. Furthermore, FTO overexpression reduced seizure frequency in rats and inhibited hippocampal neuron apoptosis via lowering the m6A methylation level of Nrf2 mRNA. Overexpressing FTO reduced m6A methylation of Nrf2 mRNA, increased cell viability, suppressed apoptosis, and slowed the progression of epileptic diseases, which is linked to YTHDF2 binding to m6A-modified Nrf2 and promoting its degradation, as well as downregulating Nrf2 expression in hippocampal neurons.

Dehydroepiandrosterone Attenuates Astroglial Activation, Neuronal Loss and Dendritic Degeneration in Iron-Induced Post-Traumatic Epilepsy

Iron-induced experimental epilepsy in rodents reproduces features of post-traumatic epilepsy (PTE) in humans. The neural network of the brain seems to be highly affected during the course of epileptogenesis and determines the occurrence of sudden and recurrent seizures. The aim of the current study was to evaluate astroglial and neuronal response as well as dendritic arborization, and the spine density of pyramidal neurons in the cortex and hippocampus of epileptic rats. We also evaluated the effect of exogenous administration of a neuroactive steroid, dehydroepiandrosterone (DHEA), in epileptic rats. To induce epilepsy, male Wistar rats were given an intracortical injection of 100 mM solution (5 µL) of iron chloride (FeCl3). After 20 days, DHEA was administered intraperitoneally for 21 consecutive days. Results showed epileptic seizures and hippocampal Mossy Fibers (MFs) sprouting in epileptic rats, while DHEA treatment significantly reduced the MFs’ sprouting. Astroglial activation and neuronal loss were subdued in rats that received DHEA compared to epileptic rats. Dendritic arborization and spine density of pyramidal neurons was diminished in epileptic rats, while DHEA treatment partially restored their normal morphology in the cortex and hippocampus regions of the brain. Overall, these findings suggest that DHEA’s antiepileptic effects may contribute to alleviating astroglial activation and neuronal loss along with enhancing dendritic arborization and spine density in PTE.

Enlightening the mechanism of ferroptosis in epileptic heart

Epilepsy is a chronic neurological degenerative disease with a high incidence, affecting all age groups. Refractory Epilepsy (RE) occurs in approximately 30-40% of cases with a higher risk of sudden unexpected death in epilepsy (SUDEP). Recent studies have shown that spontaneous seizures developed in epilepsy can be related to an increase in oxidative stress and reactive oxygen derivatives (ROS) production. Increasing ROS concentration causes lipid peroxidation, protein oxidation, destruction of nuclear genetic material, enzyme inhibition, and cell death by a mechanism known as "ferroptosis" (Fts). Inactivation of glutathione peroxidase 4 (GPX4) induces Fts, while oxidative stress is linked with increased intracellular free iron (Fe+2) concentration. Fts is also a non-apoptotic programmed cell death mechanism, where a hypoxia-inducible factor 1 alpha (HIF-141) dependent hypoxic stress-like condition appears to occur with accumulation of iron and cytotoxic ROS in affected cells. Assuming convulsive crises as hypoxic stress, repetitive convulsive/hypoxic stress can be an effective inducer of the "epileptic heart" (EH), which is characterized by altered autonomic function and a high risk of malignant or fatal bradycardia. We previously reported that experimental recurrent seizures induce cardiomyocyte Fts associated with SUDEP. Furthermore, several genes related to Fts and hypoxia have recently been identified in acute myocardial infarction. An emerging theme from recent studies indicates that inhibition of GPX4 through modulating expression or activities of the xCT antiporter system (SLC7A11) governs cell sensitivity to oxidative stress from ferroptosis. Furthermore, during hypoxia, an increased expression of stress transcriptional factor ATF3 can promote Fts induced by erastin in a HIF-141-dependent manner. We propose that inhibition of Fts with ROS scavengers, iron chelators, antioxidants, and transaminase inhibitors could provide a therapeutic effect in epilepsy and improve the prognosis of SUDEP risk by protecting the heart from ferroptosis.

Regulatory Basis of Adipokines Leptin and Adiponectin in Epilepsy: from Signaling Pathways to Glucose Metabolism

Epilepsy is a common and severe neurological disorder in which impaired glucose metabolism leads to changes in neuronal excitability that slow or promote the development of epilepsy. Leptin and adiponectin are important mediators regulating glucose metabolism in the peripheral and central nervous systems. Many studies have reported a strong association between epilepsy and these two adipokines involved in multiple signaling cascades and glucose metabolism. Due to the complex regulatory mechanisms between them and various signal activation networks, their role in epilepsy involves many aspects, including the release of inflammatory mediators, oxidative damage, and neuronal apoptosis. This paper aims to summarize the signaling pathways involved in leptin and adiponectin and the regulation of glucose metabolism from the perspective of the pathogenesis of epilepsy. In particular, we discuss the dual effects of leptin in epilepsy and the relationship between antiepileptic drugs and changes in the levels of these two adipokines. Clinical practitioners may need to consider these factors in evaluating clinical drugs. Through this review, we can better understand the specific involvement of leptin and adiponectin in the pathogenesis of epilepsy, provide ideas for further exploration, and bring about practical significance for the treatment of epilepsy, especially for the development of personalized treatment according to individual metabolic characteristics.

Predicted molecules and signaling pathways for regulating seizures in the hippocampus in lithium-pilocarpine induced acute epileptic rats: A proteomics study

Seizures in rodent models that are induced by lithium-pilocarpine mimic human seizures in a highly isomorphic manner. The hippocampus is a brain region that generates and spreads seizures. In order to understand the early phases of seizure events occurring in the hippocampus, global protein expression levels in the hippocampus on day 1 and day 3 were analyzed in lithium-pilocarpine induced acute epileptic rat models using a tandem mass tag-based proteomic approach. Our results showed that differentially expressed proteins were likely to be enhanced rather than prohibited in modulating seizure activity on days 1 and 3 in lithium-pilocarpine induced seizure rats. The differentially regulated proteins differed on days 1 and 3 in the seizure rats, indicating that different molecules and pathways are involved in seizure events occurring from day 1 to day 3 following lithium-pilocarpine administration. In regard to subcellular distribution, the results suggest that post-seizure cellular function in the hippocampus is possibly regulated in a differential manner on seizure progression. Gene ontology annotation results showed that, on day 1 following lithium-pilocarpine administration, it is likely necessary to regulate macromolecular complex assembly, and cell death, while on day 3, it may be necessary to modulate protein metabolic process, cytoplasm, and protein binding. Protein metabolic process rather than macromolecular complex assembly and cell death were affected on day 3 following lithium-pilocarpine administration. The extracellular matrix, receptors, and the constitution of plasma membranes were altered most strongly in the development of seizure events. In a KEGG pathway enrichment cluster analysis, the signaling pathways identified were relevant to sustained angiogenesis and evading apoptosis, and complement and coagulation cascades. On day 3, pathways relevant to Huntington’s disease, and tumor necrosis factor signaling were most prevalent. These results suggest that seizure events occurring in day 1 modulate macromolecular complex assembly and cell death, and in day 3 modulate biological protein metabolic process. In summary, our study found limited evidence for ongoing seizure events in the hippocampus of lithium-pilocarpine induced animal models; nevertheless, evaluating the global differential expression of proteins and their impacts on bio-function may offer new perspectives for studying epileptogenesis in the future.

Dehydroepiandrosterone activates the GPER-mediated AMPK signaling pathway to alleviate the oxidative stress and inflammatory response in laying hens fed with high-energy and low-protein diets

Fatty liver hemorrhagic syndrome (FLHS) seriously threatens the layer industry due to it can cause a sudden decline in egg production and acute death, and dietary supplement with bioactive substance is considered an effective way to prevent the FLHS occurrence. Dehydroepiandrosterone (DHEA) is a popular dietary supplement and it possesses anti-oxidative and anti-inflammatory functions; however, the effect and underlying mechanism about DHEA in protecting against the occurrence and development of FLHS remain elucidated. The current results showed that DHEA relieved HELP-induced decrease of egg productivity and liver injury in laying hens. Meanwhile, DHEA markedly enhanced the antioxidant capacity and then alleviated oxidative stress via activation of nuclear factor (erythroid-derived 2)-like 2 (NRF-2) signal in laying hens fed with HELP diets. In addition, DHEA significantly alleviated HELP-stimulated systemic inflammatory response by suppressing the overproduction of hepatic pro-inflammatory factors in laying hens, and further found this beneficial effect was achieved by blocking the activation of NF-κB pathway. Furthermore, we found that DHEA promoted the AMP-activated protein kinase α (AMPKα) activation and increased the G-protein-coupled estrogen receptor (GPER) expression level in laying hens fed with HELP diets. In summary, our data demonstrated that DHEA attenuates oxidative stress and inflammation through the activation of GPER-AMPK signal axis in laying hens fed with HELP diets. These results might facilitate an understanding of the benefits and mechanism of DHEA on the development of FLHS, and provide sufficient data to support it as a dietary supplement to control the FLHS-related metabolic diseases in chickens.

MicroRNA-21 Is a Versatile Regulator and Potential Treatment Target in Central Nervous System Disorders

MicroRNAs (miRNAs) are a class of endogenous, non-coding, single-stranded RNAs with a length of approximately 22 nucleotides that are found in eukaryotes. miRNAs are involved in the regulation of cell differentiation, proliferation, invasion, apoptosis, and metabolism by regulating the expression of their target genes. Emerging studies have suggested that various miRNAs play key roles in the pathogenesis of central nervous system (CNS) disorders and may be viable therapeutic targets. In particular, miR-21 has prominently emerged as a focus of increasing research on the mechanisms of its involvement in CNS disorders. Herein, we reviewed recent studies on the critical roles of miR-21, including its dysregulated expression and target genes, in the regulation of pathophysiological processes of CNS disorders, with a special focus on apoptosis and inflammation. Collectively, miR-21 is a versatile regulator in the progression of CNS disorders and could be a promising biomarker and therapeutic target for these diseases. An in-depth understanding of the mechanisms by which miR-21 affects the pathogenesis of CNS disorders could pave the way for miR-21 to serve as a therapeutic target for these conditions.

Neuroprotective potential of nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element signaling modulator cucurbitacin I upon glucose and oxygen deprivation/reperfusion (OGD/RP)

This study aimed to investigate the inhibitory effect and mechanism of Cucurbitacin I (Cu I) on apoptosis, oxidative stress, and mitophagy in PC12 cells with glucose and oxygen deprivation/reperfusion (OGD/RP) injury. OGD/RP cell injury model was established by gas anoxic cell incubator and glucose-free medium. The cells were divided into the control group, OGD/RP group, OGD/RP + Cu I group, and OGD/RP + Cu I + 2 µM nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor ML385 group. The results showed that apoptotic rate and reactive oxygen species (ROS) production were significantly increased in OGD/RP group, which were reversed by Cu I pretreatment. Meanwhile, western blot analysis proved that Cu I inhibited OGD/RP-induced mitophagy, manifested as the decreased expression of PTEN-induced kinase 1 (PINK1) and parkin RBR E3 ubiquitin-protein ligase (Parkin), and light chain 3 (LC3) Ⅱ∕LC3 I, as well as the increased expression of P62. Furthermore, immunofluorescence (IF) staining showed that Cu I reduced the co-localized puncta of LC3 with TOM20 in OGD/RP-induced PC12 cells. Similarly, transmission electron microscope finding is consistent with the IF results. Mechanically, after Cu I and OGD/RP treatments, nuclear Nrf2 expression and the levels of downstream target genes were significantly upregulated compared with OGD/RP alone treatment. Nrf2 inhibition reversed the protective effects of Cu I on OGD/RP-induced injury in PC12 cells. The present study provides evidence of the neuroprotective effect of Cu I unraveling its potential as a potential therapeutic candidate for the treatment of ischemic stroke.

The effects of Hippophae rhamnoides in neuroprotection and behavioral alterations against iron-induced epilepsy

Epilepsy is a neurological disorder in which malfunctioning of the electrical activity of the brain causes recurrent, unprovoked seizures. Epilepsy causes wide symptoms that include cognitive dysfunction, anxiety, behavioral alterations, and histological impairments. In this study, the effect of Hippophae rhamnoides (Sea buckthorn/Sbt) on electrophysiology, behavior, and histology in iron-induced epilepsy was analyzed. Rats were randomly divided into four groups (n = 8); Control group, Epileptic group, Sbt treated epileptic group, and Sbt treated group. To induce epilepsy, the intracortical iron injection was administered at a dose of 5 μl of 100 mM FeCl₃. A significant increase in epileptiform activity, behavioral abnormalities, and histological impairments was observed in the iron-induced epileptic rats. Hippophae rhamnoides berry extract was administered orally at a dose of 1 ml/kg body wt. for one month. Sbt administration significantly reduced the epileptiform activity, improved behavioral abnormalities, and improved histological impairments in epileptic rats. In conclusion, this study demonstrates the antiepileptic effect of Sbt that probably has exerted by its neuroprotective and behavioral alteration potential against iron-induced epilepsy.

The protective effect of hydroxylated fullerene pretreatment on pilocarpine-induced status epilepticus

Status epilepticus (SE) is a neurological emergency. The pathological hallmark of neuronal damage after epileptic seizures could be the chain reaction of oxygen free radicals. Hydroxylated fullerenes (HFs) are novel and effective free radical scavengers, which play an important role in various neurological diseases. However, whether they have a protective effect against epileptic seizures remains elusive. Our study explores the effect of pretreatment with HFs in different doses (0.5, 5, and 10 mg/kg) on SEmodels induced by pilocarpine (PILO). The results suggest that HFs have a protective effect on SE in a dose-dependent manner. HFs significantly reduce the incidence of SE, prolong the latency to SE, reduce the malondialdehyde (MDA) levels, and increase the glutathione (GSH) and superoxide dismutase (SOD) levels. In addition, HFs significantly raise the expression of B-cell lymphoma-2 (Bcl-2) and reduce the expression of Bcl-2-associated X protein (Bax). We found that expressions of nuclear NF-E2-related factor 2 (nNrf2), heme oxygenase-1 (HO-1) and NADPH: quinone oxidoreductase-1 (NQO1) were upregulated 24 h after the onset of SE, but the increase was not enough to combat oxidative stress damage, nor to attenuate lipid peroxidation and apoptosis. The expressions of these proteins in HFs pretreatment groups increased more significantly than those in the epilepsy (EP) group, which effectively reduced lipid peroxidation and apoptosis in the hippocampus. In summary, these findings highlight that HFs pretreatment has a protective effect against PILO-induced SE in rats. It may relieve oxidative stress damage by activating the Nrf2-ARE signaling pathway. It provides evidence that fullerene derivatives may have therapeutic potential for epileptic seizures.

Antioxidant activity of mesenchymal stem cell-derived extracellular vesicles restores hippocampal neurons following seizure damage

Oxidative stress is a critical event in neuronal damage following seizures. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been shown to be promising nanotherapeutic agents in neurological disorders. However, the mechanism underlying MSC-EVs therapeutic efficacy for oxidative stress-induced neuronal damage remains poorly understood.

Methods: We investigated the antioxidant and restoration activities of MSC-EVs on hippocampal neurons in response to H₂O₂ stimulation in vitro and seizures in vivo. We also explored the potential underlying mechanism by injecting adeno-associated virus (AAV)-nuclear factor erythroid-derived 2, like 2 (Nrf2), a key antioxidant mediator, in animal models.

Results: MSC-EVs were enriched in antioxidant miRNAs and exhibited remarkable antioxidant activity evident by increased ferric ion-reducing antioxidant ability, catalase, superoxide dismutase, and glutathione peroxidase activities and decreased reactive oxygen species (ROS) generation, DNA/lipid/protein oxidation, and stress-associated molecular patterns in cultured cells and mouse models. Notably, EV administration exerted restorative effects on the hippocampal neuronal structure and associated functional impairments, including dendritic spine alterations, electrophysiological disturbances, calcium transients, mitochondrial changes, and cognitive decline after oxidative stress in vitro or in vivo. Mechanistically, we found that the Nrf2 signaling pathway was involved in the restorative effect of EV therapy against oxidative neuronal damage, while AAV-Nrf2 injection attenuated the antioxidant activity of MSC-EVs on the seizure-induced hippocampal injury.

Conclusions: We have shown that MSC-EVs facilitate the reconstruction of hippocampal neurons associated with the Nrf2 defense system in response to oxidative insults. Our study highlights the clinical value of EV-therapy in neurological disorders such as seizures.

DHEA-pretreatment attenuates oxidative stress in kidney-cortex and liver of diabetic rabbits and delays development of the disease

In view of reported discrepancies concerning antioxidant activity of dehydroepiandrosterone (DHEA), a widely used dietary supplement, the current investigation was undertaken to evaluate the antioxidant properties of DHEA in both kidney-cortex and liver of alloxan (ALX)-induced diabetic rabbits, as this diabetogenic compound exhibits the ROS-dependent action. ALX was injected to animals following 7 days of DHEA administration. Four groups of rabbits were used in the experiments: control, DHEA-treated control, diabetic and DHEA-treated diabetic. Our results show for the first time, that in kidney-cortex DHEA resulted in normalization of hydroxyl free radicals (HFR) levels and restoration of catalase (CAT) and glutathione peroxidase (GPx) activities to near the control values, while in liver DHEA prevented the malondialdehyde (MDA) accumulation and normalized glutathione reductase (GR) and glucose-6-phosphate dehydrogenase (G6PDH) activities. Moreover, in both kidney-cortex and liver DHEA supplementation prevented GSSG elevation accompanied by a decrease in GSH/GSSG ratio. Although DHEA attenuated oxidative stress in both kidney-cortex and liver of ALX-induced diabetic rabbits and significantly delayed the onset of diabetes in time, it did not protect against the final development of diabetes. In conclusion, the current investigation underscores the complexity of the antioxidant action of DHEA. The data are of clinical interest since DHEA supplementation could prevent the deleterious effects of ROS and delay, or even prevent the onset of many diseases. However, in view of the reported pro-oxidant effects of high DHEA doses, the potential use of this agent as a supplement needs a careful evaluation.

Response of Voltage-Gated Sodium and Calcium Channels Subtypes on Dehydroepiandrosterone Treatment in Iron-Induced Epilepsy

Epilepsy is a neurological disorder characterized by the occurrence of spontaneous and recurrent seizures. In post-traumatic epilepsy (PTE), the mechanism of epileptogenesis is very complex and seems to be linked with voltage-gated ion channels. Dehydroepiandrosterone (DHEA), a neurosteroid have shown beneficial effect against various neurological disorders. We investigated antiepileptic effect of DHEA with respect to expression of voltage-gated ion channels subtypes in iron-induced epilepsy. Iron (FeCl3) solution was intracartically injected to induce epilepsy in rats and DHEA was intraperitoneally administered for 21 days. Results showed markedly increased epileptiform seizures activity along with up-regulation of Nav1.1 and Nav1.6, and down-regulation of Cav2.1α at the mRNA and protein level in the cortex and hippocampus of epileptic rats. Moreover, the study demonstrated that these channels subtypes were predominantly expressed in the neurons. DHEA treatment has countered the epileptic seizures, down-regulated Nav1.1 and Nav1.6, and up-regulated Cav2.1α without affecting their cellular localization. In conclusion, the present study demonstrates antiepileptic potential of DHEA, escorted by regulation of Nav1.1, Nav1.6, and Cav2.1α subtypes in the neurons of iron-induced epileptic rats.

Dehydroepiandrosterone attenuates LPS-induced inflammatory responses via activation of Nrf2 in RAW264.7 macrophages

Dehydroepiandrosterone (DHEA) is the major steroid hormone in humans and animals, which can regulate the body's inflammatory responses. However, the detail mechanism of this beneficial function is still poorly understood. The present study aimed to explore the anti-inflammation effect of DHEA and its underlying molecular mechanism in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. The findings showed that DHEA significantly inhibited the inflammation-related mediators production and pro-inflammatory cytokines expression level. Further research found that DHEA obviously blocked the LPS-stimulated PI3K/AKT, MAPK and NF-κB activation in RAW 264.7 cells. Meanwhile, DHEA enhanced the autophagy-dependent Keap1 protein degradation, subsequently activated the Nrf2 pathway to alleviate the redox imbalance and inflammatory responses. In conclusion, our data demonstrated that DHEA suppresses inflammatory responses through the activation of Nrf2 and inhibition of NF-κB in LPS-stimulated macrophages.

Iron Metabolism and Ferroptosis in Epilepsy

Epilepsy is a disease characterized by recurrent, episodic, and transient central nervous system (CNS) dysfunction resulting from an excessive synchronous discharge of brain neurons. It is characterized by diverse etiology, complex pathogenesis, and difficult treatment. In addition, most epileptic patients exhibit social cognitive impairment and psychological impairment. Iron is an essential trace element for human growth and development and is also involved in a variety of redox reactions in organisms. However, abnormal iron metabolism is associated with several neurological disorders, including hemorrhagic post-stroke epilepsy and post-traumatic epilepsy (PTE). Moreover, ferroptosis is also considered a new form of regulation of cell death, which is attributed to severe lipid peroxidation caused by the production of reactive oxygen species (ROS) and iron overload found in various neurological diseases, including epilepsy. Therefore, this review summarizes the study on iron metabolism and ferroptosis in epilepsy, in order to elucidate the correlation between iron and epilepsy. It also provides a novel method for the treatment, prevention, and research of epilepsy, to control epileptic seizures and reduce nerve injury after the epileptic seizure.

Ameliorative effect of curcumin on altered expression of CACNA1A and GABRD in the pathogenesis of FeCl3-induced epilepsy

The pivotal role played by ion-channel dysregulations in the pathogenesis of epilepsy has always garnered much attention. Since mutation of ion-channel proteins CACNA1A and GABRD have been associated with epilepsy, it is important to determine the post-traumatic epilepsy-associated changes in expression levels of these ion channel proteins. Additionally, curcumin is already known for its antiepileptic and neuroprotective potential in FeCl₃-induced model of post-traumatic epilepsy. Thus, we investigated FeCl₃-induced epilepsy mediated differential expression of CACNA1A and GABRD in the cortical region of the rat brain. Furthermore, we investigated the effect of curcumin on the expression of both proteins. For this, epilepsy was induced by intracortical FeCl₃ injection (5 μl of 100 mM). Additionally, curcumin (conc. 1000 ppm; 75 mg/kg of b.wt.; for 14 and 28 days) was administered, mixed with normal food pellets. Results obtained from EEG-MUA and Morris water maze assay demonstrate the progression of epilepsy after FeCl₃ injection. Additionally, western blotting and histological studies show the downregulation of CACNA1A and GABRD during epileptogenesis. It was observed that epilepsy-associated decline in learning and memory of animals might be linked with the dysregulation of both proteins. Results also demonstrated that curcumin administration ameliorated epilepsy-associated change in expression of both CACNA1A and GABRD proteins. In conclusion, the neuroprotective effect of curcumin against iron-induced epilepsy might be accompanied by the alleviated upregulation of these channel proteins.

Nicotine Alleviates Cortical Neuronal Injury by Suppressing Neuroinflammation and Upregulating Neuronal PI3K-AKT Signaling in an Eclampsia-Like Seizure Model

Our previous studies showed that treatment with alpha7 nicotinic acetylcholine receptor (α7nAChR) agonist nicotine could alleviate systemic inflammation and reduce neuronal loss in the hippocampus and seizure severity in eclampsia. In this study, we further investigated whether there is also neuronal damage in the cortex after eclamptic seizure, elucidated the potential mechanisms underlying the neuroprotective roles of nicotine in eclampsia. Retrospective analysis of MRI data of severe preeclampsia (SPE) patients was conducted. A preeclampsia model was established by lipopolysaccharide injection (PE group), and pentylenetetrazol was used to induce eclamptic seizure (E group). α7nAChR agonist nicotine and its antagonist (α-BGT) and PI3K inhibitor wortmannin were used for drug administration. Neuronal damage was detected by Nissl staining, and changes in neuroinflammation, neuronal apoptosis, α7nAChR expression, and PI3K-AKT signaling on cortical neurons were detected by immunohistochemistry and western blotting. MRI images showed that most abnormal signals from the brain of SPE patients were located in the cortex. The neuron survival ratio was lower in the cortex than in the hippocampus within the E group; such ratios in the cortex were significantly lower in the E and PE groups compared with those of the control group. Nicotine markedly decreased the production of inflammatory cytokines and microglial activation in the cortex of the E group. Moreover, nicotine increased p-AKT levels and decreased cleaved caspase-3 levels in cortical neurons. Treatment with α-BGT reversed effects of nicotine. Wortmannin also blocked the anti-neuronal apoptosis action of nicotine. Our results suggest that nicotine protects against neuronal injury in the cortex following eclampsia possibly by inhibiting neuroinflammation and activating neuronal PI3K-AKT pathway.

Effect of dehydroepiandrosterone on the immune response and gut microbiota in dextran sulfate sodium-induced colitis mice

Dehydroepiandrosterone (DHEA) possess anti-inflammatory, anti-oxidant and immune-regulating function in animals and humans, but there is not enough information about the mechanisms underlying its beneficial effects. The present study investigated the effect and mechanism of DHEA in dextran sulfate sodium (DSS)-induced colitis mice. The findings showed that DHEA relieved the decreasing of body weight, the increasing of disease activity index, the enhancing of spleen weight, the shortening of colon length and the rising of myeloperoxidase activity; meanwhile, histopathological analysis showed that DHEA maintained a relatively intact structure of colon in DSS-induced colitis mice. DHEA decreased the malondialdehyde content, superoxide dismutase activity and inducible nitric oxide synthase protein level; meanwhile, DHEA also inhibited the secretion of tumor necrosis factor-α, interleukin-1β and interleukin-6 in DSS-induced colitis mice. Importantly, our results showed that DHEA blocked the activation of nuclear factor-kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) pathways; and it inhibited the Nod-like receptor protein 3 inflammasome activation in DSS-induced colitis mice. Furthermore, DHEA markedly promoted the intestinal barrier function by up-regulation zonula occludens-1 expression level. The 16S rDNA gene sequencing demonstrated that DHEA decreased the Pseudomonas abundance in DSS-induced colitis mice. In conclusion, our data demonstrated that DHEA reduces oxidative damage through regulating antioxidant enzyme activity; inhibits pro-inflammatory cytokines production by blocking the activation of p38 MAPK and NF-κB signal pathway; protects colon barrier integrity via increasing tight junction protein expression and modulating gut microbiota taxa; all that finally alleviates DSS-induced experimental colitis in mice.