Oxidation-reduction mechanisms in psychiatric disorders: A novel target for pharmacological intervention

Mercuric Chloride Aggravates Hyperglycemia-Induced Anxiety and Depressive-Like Behaviors in Type 2 Diabetic Rats: Breakdown of the Antioxidant Defense System

Introduction Type 2 diabetes mellitus (T2DM) is a global health problem frequently associated with biochemical disturbance and also, with a range of mental health disorders including such as anxiety and depression. Whereas, mercury chloride (HgCl₂) is a common environmental pollutant, which is neurotoxic and induces oxidative stress, especially in metabolic disorders like diabetes. The purpose of this investigation is to evaluate the interaction between hyperglycemia-induced oxidative stress and HgCl₂ toxicity and to assess their far-reaching effect spotlighted on biochemical and behavioral disturbances. By analyzing key oxidative stress markers and anxiety- and depression-like behaviors. Experimental design was carried out as follow: control group, HgCl₂-treated group, diabetic group and diabetic HgCl₂-treated group. Type 2 diabetes was induced in a diabetic model via streptozotocin (STZ) and nicotinamide (NA) injections. For the HgCl₂-exposed groups, rats were administered 0.375 mg/kg/day of HgCl₂ orally for 45 consecutive days. Additionally, behavioral tests were performed to examine anxiety- and depression-like behaviors, and hematological, biochemical, oxidative stress markers were assessed to evaluate systemic and neurotoxic effects. The results showed significant increases in fasting blood glucose levels in diabetic and HgCl₂-treated diabetic groups compared to controls (p < 0.001). Body weight significantly decreased in all treated groups (p < 0.05), with the greatest reduction observed in the HgCl₂-treated diabetic group. Behavioral analysis revealed heightened anxiety and depression-like behaviors, particularly in the HgCl₂-treated diabetic group (p < 0.05). Biochemical assessments indicated significant disruptions in lipid profiles and hepatic and renal markers, with pronounced effects in HgCl₂-treated diabetic rats (p < 0.05). Oxidative stress markers demonstrated elevated malondialdehyde and nitric oxide levels in the liver, hippocampus, and prefrontal cortex, paired with diminished antioxidant defences, including catalase and superoxide dismutase activities (p < 0.05). These findings underscore the synergistic role of hyperglycemia and HgCl₂ exposure in amplifying oxidative damage and emotional disturbances, suggesting a critical interplay between metabolic and neurotoxic pathways.

Local patterns of genetic sharing between neuropsychiatric and insulin resistance-related conditions

The co-occurrence of insulin resistance (IR)-related metabolic conditions with neuropsychiatric disorders is a major public health challenge. Evidence of the genetic links between these phenotypes is emerging, but little is currently known about the genomic regions and biological functions that are involved. To address this, we performed Local Analysis of [co]Variant Association (LAVA) using large-scale (N = 9,725-933,970) genome-wide association studies (GWASs) results for three IR-related conditions (type 2 diabetes mellitus, obesity, and metabolic syndrome) and nine neuropsychiatric disorders. Subsequently, positional and expression quantitative trait locus (eQTL)-based gene mapping and downstream functional genomic analyses were performed on the significant loci. Patterns of negative and positive local genetic correlations (|rg| = 0.21-1, pFDR < 0.05) were identified at 109 unique genomic regions across all phenotype pairs. Local correlations emerged even in the absence of global genetic correlations between IR-related conditions and Alzheimer's disease, bipolar disorder, and Tourette's syndrome. Genes mapped to the correlated regions showed enrichment in biological pathways integral to immune-inflammatory function, vesicle trafficking, insulin signalling, oxygen transport, and lipid metabolism. Colocalisation analyses further prioritised 10 genetically correlated regions for likely harbouring shared causal variants, displaying high deleterious or regulatory potential. These variants were found within or in close proximity to genes, such as SLC39A8 and HLA-DRB1, that can be targeted by supplements and already known drugs, including omega-3/6 fatty acids, immunomodulatory, antihypertensive, and cholesterol-lowering drugs. Overall, our findings highlight the complex genetic architecture of IR-neuropsychiatric multimorbidity, advocating for an integrated disease model and offering novel insights for research and treatment strategies in this domain.

Ginkgo biloba L. leaf extract (EGb 761) alleviates reserpine-induced depression-like symptoms in aged rats by enhancing serotonin/norepinephrine levels and reducing oxidative/nitrosative stress

Along with accelerated aging, the prevalence of late-life depression (LLD) exacerbates. Older people are more vulnerable to the adverse effects of antidepressants than the young. Therefore, creating antidepressants from medicinal herbs that are more effective and safer is inevitable. Ginkgo biloba L. leaf extract (EGb761) is broadly applied for treating various neuronal dysfunctions. The present study aimed to evaluate the ameliorative and antidepressant effects of EGb761 against reserpine (RES)-induced depression like symptoms and associated comorbidities in aged female rats. Besides, it compared its efficacy with the antidepressant duloxetine (DULX), offering a more comprehensive understanding of therapeutic potential of EGb 761. Rats grouped into control group, EGb 761-H group, RES group, RES plus either EGb 761-L, EGb 761-H, or DULX groups. The antidepressant effects of EGb 761 were evaluated through a series of behavioral tests, measurement of depression biochemical markers, performing neuronal histopathology and immunohistochemical analyses. EGb 761 significantly attenuated behavioral deficits in the open field test and reduced immobility time in the forced swimming test. Moreover, EGb 761 exerted antidepressant-like actions by ameliorating neurotransmitter imbalances, restoring redox homeostasis in cortical region. Also, EGb 761 increased level of ATP, diminished DNA fragmentation, decreased caspase-3 immunoreactivity and increased immunoreactivity of synaptophysin in the cerebral cortex, besides it enhanced the histological architecture of this region. Overall, EGb 761 has the potential effects to manage LLD focus on the role of both serotonergic and noradrenergic systems in mediating these effects, alongside the impact on oxidative/nitrosative stress.

Causal Impacts of Psychiatric Disorders on Cognition and the Mediating Effect of Oxidative Stress: A Mendelian Randomization Study

Many psychiatric disorders are associated with major cognitive deficits. However, it is uncertain whether these deficits develop as a result of psychiatric disorders and what shared risk factors might mediate this relationship. Here, we utilized the Mendelian randomization (MR) analysis to investigate the complex causal relationship between nine major psychiatric disorders and three cognitive phenotypes, while also examining the potential mediating role of oxidative stress as a shared biological underpinning. Schizophrenia (SZ), major depressive disorder (MDD), and attention deficit hyperactivity disorder (ADHD) showed a decreasing effect on cognitive performance, intelligence, and education, while bipolar disorder (BPD) increased educational attainment. MR-Clust results exhibit the shared genetic basis between SZ and other psychiatric disorders in relation to cognitive function. Furthermore, when oxidative stress was considered as a potential mediating factor, the associations between SZ and the three dimensions of cognition, as well as between MDD and intelligence and ADHD and intelligence, exhibited larger effect sizes than the overall. Mediation MR analysis also supported the causal effects between psychiatric disorders and cognition via oxidative stress traits, including carotene, vitamin E, bilirubin, and uric acid. Finally, summary-based MR identified 29 potential causal associations of oxidative stress genes with both cognitive performance and psychiatric disorders. Our findings highlight the importance of considering oxidative stress in understanding and potentially treating cognitive impairments associated with psychiatric conditions.

Antioxidants in neuropsychiatric disorder prevention: neuroprotection, synaptic regulation, microglia modulation, and neurotrophic effects

Oxidative stress, caused by an imbalance between the generation of reactive oxygen species (ROS) and the body's intrinsic antioxidant defenses, plays a critical role in neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's. Beyond these conditions, recent evidence indicates that dysregulated redox balance is implicated in neuropsychiatric disorders, including schizophrenia, major depressive disorder, and anxiety disorders. Preclinical and clinical studies have demonstrated the potential of antioxidants, such as N-acetylcysteine, sulforaphane, alpha-lipoic acid, L-carnitine, ascorbic acid, selenocompounds, flavones and zinc, in alleviating neuropsychiatric symptoms by mitigating excitotoxicity, enhancing synaptic plasticity, reducing microglial overactivation and promoting synaptogenesis. This review explores the role of oxidative stress in the pathogenesis of neuropsychiatric disorders. It provides an overview of the current evidence on antioxidant therapy's pharmacological effects, as demonstrated in animal models and clinical studies. It also discusses the underlying mechanisms and future directions for developing antioxidant-based adjuvant therapies. Given the limitations and side effects of existing treatments for neuropsychiatric disorders, antioxidant therapy presents a promising, safer alternative. Further research is essential to deepen our understanding and investigate the clinical efficacy and mechanisms underlying these therapies.

"RNSP (Rannasangpei)" Rescued MK-801-induced Schizophrenia-like Behaviors in Mice via Oxidative Stress and BDNF-TrkB/Akt Pathway

Schizophrenia (SCZ) is a complex, severe psychotic disorder that is highly persistent. Patients often cannot control their emotions and have delusions of victimization, world-weariness, and even suicide. Therefore, safer and more effective drugs are urgently needed. Rannasangpei (RNSP) from "the four medicine tantras" was used as a neuroprotective agent. The objective of this study was to investigate the effect and mechanism of RNSP on MK-801-induced SCZ in mice. Fifty C57BL/6J mice were randomly divided into a normal group, a model group, an RNSP group, a crocin (CRO) group, and an olanzapine (OLA) group, except for the normal group. The remaining mice were used to establish the MK-801-induced SCZ model. Changes in positive symptoms and cognitive impairment in mice before and after drug intervention were assessed by using the prepulse inhibition (PPI) test, Y-maze test (YMT), and open-field test (OFT). Intragastric administration of RNSP alleviated the symptoms of SCZ in SCZ mice, as demonstrated by the PPI, YMT, and OFT results. Compared with the model group, the first-line antipsychotic olanzapine reversed the anxiety-like phenotypes, hypermotility, and PPI deficits in the SCZ model mice. Further analysis revealed that RNSP reduced oxidative stress in SCZ model mice, as evidenced by increased superoxide dismutase (SOD) levels and decreased malondialdehyde (MDA) levels in the hippocampus, cortex, and blood of SCZ model mice. In our study, RNSP treatment restored the expression of brain-derived neurotrophic factor (BDNF), dopamine D2 receptor, p-Trkb, Akt/p-Akt, and doublecortin and inhibited the expression of IBA1 and Bax in the hippocampus of SCZ model mice. The polymerase chain reaction data indicated that RNSP treatment increased the expression of Bcl-2 and TGF-β and decreased the expression of Bax, IL-1β, and TNF-α in the brains of the model mice. Our results are the first to show that RNSP reverses SCZ-like behaviors in rodents (both positive symptoms and cognitive deficits) by reducing oxidative stress and activating the BDNF-TrkB/Akt pathway, suggesting that RNSP is a novel approach for treating SCZ.

Inhibition of reactive oxygen species production accompanying alternatively activated microglia by risperidone in a mouse ketamine model of schizophrenia

Recent studies have highlighted the potential involvement of reactive oxygen species (ROS) and microglia, a major source of ROS, in the pathophysiology of schizophrenia. In our study, we explored how the second-generation antipsychotic risperidone (RIS) affects ROS regulation and microglial activation in the hippocampus using a mouse ketamine (KET) model of schizophrenia. KET administration resulted in schizophrenia-like behaviors in male C57BL/6J mice, such as impaired prepulse inhibition (PPI) of the acoustic startle response and hyper-locomotion. These behaviors were mitigated by RIS. We found that the gene expression level of an enzyme responsible for ROS production (Nox2), which is primarily associated with activated microglia, was lower in KET/RIS-treated mice than in KET-treated mice. Conversely, the levels of antioxidant enzymes (Ho-1 and Gclc) were higher in KET/RIS-treated mice. The microglial density in the hippocampus was increased in KET-treated mice, which was counteracted by RIS. Hierarchical cluster analysis revealed three morphological subtypes of microglia. In control mice, most microglia were resting-ramified (type I, 89.7%). KET administration shifted the microglial composition to moderately ramified (type II, 44.4%) and hyper-ramified (type III, 25.0%). In KET/RIS-treated mice, type II decreased to 32.0%, while type III increased to 34.0%. An in vitro ROS assay showed that KET increased ROS production in dissociated hippocampal microglia, and this effect was mitigated by RIS. Furthermore, we discovered that a NOX2 inhibitor could counteract KET-induced behavioral deficits. These findings suggest that pharmacological inhibition of ROS production by RIS may play a crucial role in ameliorating schizophrenia-related symptoms. Moreover, modulating microglial activation to regulate ROS production has emerged as a novel avenue for developing innovative treatments for schizophrenia.

Early life adversities, psychopathologies and novel pharmacological strategies

Exposure to adversities during early life stages (early life adversities - ELA), ranging from pregnancy to adolescence, represents a major risk factor for the vulnerability to mental disorders. Hence, it is important to understand the molecular and functional underpinning of such relationship, in order to develop strategies aimed at reducing the psychopathologic burden associated with ELA, which may eventually lead to a significant improvement in clinical practice. In this review, we will initially recapitulate clinical and preclinical evidence supporting the link between ELA and psychopathology and we will primarily discuss the main biological mechanisms that have been described as potential mediators of the effects of ELA on the psychopathologic risk, including the role for genetic factors as well as sex differences. The knowledge emerging from these studies may be instrumental for the development of novel therapeutic strategies aimed not only at correcting the deficits that emerge from ELA exposure, but also in preventing the manifestation of a full-blown psychopathologic condition. With this respect, we will specifically focus on adolescence as a key time frame for disease onset as well as for early therapeutic intervention. We believe that incorporating clinical and preclinical research data in the context of early life adversities can be instrumental to elucidate the mechanisms contributing to the risk for psychopathology or that may promote resilience. This will ultimately allow the identification of 'at risk' individuals who may benefit from specific forms of interventions that, by interfering with disease trajectories, could result in more benign clinical outcomes.

The Association of Redox Regulatory Drug Target Genes with Psychiatric Disorders: A Mendelian Randomization Study

Redox regulatory drug (RRD) targets may be considered potential novel drug targets of psychosis due to the fact that the brain is highly susceptible to oxidative stress imbalance. The aim of the present study is to identify potential associations between RRD targets' perturbation and the risk of psychoses; to achieve this, Mendelian randomization analyses were conducted. The expression quantitative trait loci (eQTL) and protein QTL data were used to derive the genetic instrumental variables. We obtained the latest summary data of genome-wide association studies on seven psychoses as outcomes, including schizophrenia (SCZ), bipolar disorder (BD), major depressive disorder (MDD), attention-deficit/hyperactivity disorder, autism, obsessive-compulsive disorder and anorexia nervosa. In total, 95 unique targets were included in the eQTL panel, and 48 targets in the pQTL one. Genetic variations in the vitamin C target (OGFOD2, OR = 0.784, p = 2.14 × 10-7) and melatonin target (RORB, OR = 1.263, p = 8.80 × 10-9) were significantly related to the risk of SCZ. Genetic variation in the vitamin E (PRKCB, OR = 0.248, p = 1.24 × 10-5) target was related to an increased risk of BD. Genetic variation in the vitamin C target (P4HTM: cerebellum, OR = 1.071, p = 4.64 × 10-7; cerebellar hemisphere, OR = 1.092, p = 1.98 × 10-6) was related to an increased risk of MDD. Cognitive function mediated the effects on causal associations. In conclusion, this study provides supportive evidence for a causal association between RRD targets and risk of SCZ, BD or MDD, which were partially mediated by cognition.

Local patterns of genetic sharing challenge the boundaries between neuropsychiatric and insulin resistance-related conditions

The co-occurrence of insulin resistance (IR)-related metabolic conditions with neuropsychiatric disorders is a complex public health challenge. Evidence of the genetic links between these phenotypes is emerging, but little is currently known about the genomic regions and biological functions that are involved. To address this, we performed Local Analysis of [co]Variant Association (LAVA) using large-scale (N=9,725-933,970) genome-wide association studies (GWASs) results for three IR-related conditions (type 2 diabetes mellitus, obesity, and metabolic syndrome) and nine neuropsychiatric disorders. Subsequently, positional and expression quantitative trait locus (eQTL)-based gene mapping and downstream functional genomic analyses were performed on the significant loci. Patterns of negative and positive local genetic correlations (|rg|=0.21-1, pFDR<0.05) were identified at 109 unique genomic regions across all phenotype pairs. Local correlations emerged even in the absence of global genetic correlations between IR-related conditions and Alzheimer's disease, bipolar disorder, and Tourette's syndrome. Genes mapped to the correlated regions showed enrichment in biological pathways integral to immune-inflammatory function, vesicle trafficking, insulin signalling, oxygen transport, and lipid metabolism. Colocalisation analyses further prioritised 10 genetically correlated regions for likely harbouring shared causal variants, displaying high deleterious or regulatory potential. These variants were found within or in close proximity to genes, such as SLC39A8 and HLA-DRB1, that can be targeted by supplements and already known drugs, including omega-3/6 fatty acids, immunomodulatory, antihypertensive, and cholesterol-lowering drugs. Overall, our findings underscore the complex genetic landscape of IR-neuropsychiatric multimorbidity, advocating for an integrated disease model and offering novel insights for research and treatment strategies in this domain.

Effects of Nostoc commune extract on the cerebral oxidative and neuroinflammatory status in a mice model of schizophrenia

Cyanobacterium Nostoc commune has long been used to alleviate various diseases. This research examines the effects of Nostoc commune extract (NCE) against behavioral disorders, cerebral oxidative stress, and inflammatory damage in the ketamine-induced schizophrenia model. Oral NCE administration (70 and 150 mg/kg/d) is performed after intraperitoneal ketamine injection (20 mg/kg) for 14 consecutive days. The forced swimming and open field tests are used to assess schizophrenia-like behaviors. After the behavioral test, dopamine (DA) level, oxidative stress markers, as well as the interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) expression are measured in the cerebral cortex. The results show that NCE treatment ameliorates KET-induced anxiety and depressive-like behaviors in OFT and FST, respectively. NCE considerably decreases the malondialdehyde (MDA) and DA levels and IL-6 and TNF-α expressions in mice with schizophrenia-like symptoms. Also, a significant increase is observed in the glutathione (GSH) level and catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GRx) activity in cerebral tissue. The present study shows that NCE treatment effectively improves KET-induced schizophrenia-like behaviors and oxidative and inflammatory damage. Therefore, NCE, via its bioactive constituents, could have strong neuroprotective effects in the schizophrenia-like model.

Joint association of heavy metals and polycyclic aromatic hydrocarbons exposure with depression in adults

BACKGROUND

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) represent significant components of environmental pollution, typically occurring as mixtures, raising concerns about their potential impact on human health. However, the combined effect of HMs and PAHs exposure on depression has not been explored.

METHODS

Leveraging National Health and Nutrition Examination Survey (NHANES) data spanning 2005 to 2016, we employ survey-weighted multiple logistic regression models to probe the interrelation between HMs, PAHs, and depression. This exploration is complemented by age and gender-stratified analyses, as well as a determination of the dose-response linkage via restricted cubic spline regression. Furthermore, the combined impact of HMs and PAHs on depression was evaluated through a range of statistical methodologies.

RESULTS

The study encompasses 7732 adults. Our findings unveil notable associations, indicating the significant influence of cadmium (Cd), lead (Pb), and all six PAHs metabolites on depression. Moreover, mixed exposure to HMs and PAHs emerges as a substantial contributor to an augmented depression risk, with Cd, Pb, 1-hydroxynaphthalene (1-NAP), 2-hydroxyfluorene (2-FLU), and 1-hydroxypyrene (1-PYR) likely driving this positive relationship. Intriguingly, subgroup analyses highlight greater prominence of these connections among individuals aged 20-59 and among women. Furthermore, the results tentatively suggest a potential interplay between Cd and 2-NAP in relation to depression.

CONCLUSION

This study posits that exposure to both individual and combined HMs and PAHs may be associated with an elevated risk of depression. Further prospective investigations are warranted to substantiate these findings.

Boltzmann's Theorem Revisited: Inaccurate Time-to-Action Clocks in Affective Disorders

Timely goal-oriented behavior is essential for survival and is shaped by experience. In this paper, a multileveled approach was employed, ranging from the polymorphic level through thermodynamic molecular, cellular, intracellular, extracellular, non-neuronal organelles and electrophysiological waves, attesting for signal variability. By adopting Boltzmann's theorem as a thermodynamic conceptualization of brain work, we found deviations from excitation-inhibition balance and wave decoupling, leading to wider signal variability in affective disorders compared to healthy individuals. Recent evidence shows that the overriding on-off design of clock genes paces the accuracy of the multilevel parallel sequencing clocks and that the accuracy of the time-to-action is more crucial for healthy behavioral reactions than their rapidity or delays. In affective disorders, the multilevel clocks run free and lack accuracy of responsivity to environmentally triggered time-to-action as the clock genes are not able to rescue mitochondria organelles from oxidative stress to produce environmentally-triggered energy that is required for the accurate time-to-action and maintenance of the thermodynamic equilibrium. This maintenance, in turn, is dependent on clock gene transcription of electron transporters, leading to higher signal variability and less signal accuracy in affective disorders. From a Boltzmannian thermodynamic and energy-production perspective, the option of reversibility to a healthier time-toaction, reducing entropy is implied. We employed logic gates to show deviations from healthy levelwise communication and the reversed conditions through compensations implying the role of nonneural cells and the extracellular matrix in return to excitation-inhibition balance and accuracy in the time-to-action signaling.

Increased levels of lipid and protein oxidation in rat prefrontal cortex after treatment by lithium, valproic acid, and olanzapine

Oxidative stress is widely accepted to contribute to the pathogenesis of several psychiatric diseases. Many antipsychotic drugs and mood stabilizers act through restoration of the dysregulated oxidative homeostasis in the brain. However, the long-term effect of these drugs per se in terms of their potential to interfere with the oxidative status in the brain remains largely controversial. The present study aimed to investigate the sole effect of three commonly used psychoactive drugs, lithium, valproic acid, and olanzapine, on lipid and protein oxidation status in the prefrontal cortex of healthy rats. A total of 80 adult male albino Wistar rats were used, and groups were treated with saline (control), lithium, valproic acid, or olanzapine daily for 30 days. Following sacrification, right prefrontal cortexes were dissected and homogenized. Lipid peroxidation (LPO) and protein oxidation (AOPP) assays were performed by ELISA. LPO levels were significantly higher in lithium and valproic acid-treated rats by 45% and 40%, respectively. Olanzapine treatment caused a mild 26% increase in LPO levels, but the effect was non-significant. Lithium, valproic acid, and olanzapine treatments significantly increased AOPP levels by 58%, 54%, and 36.5%, respectively. There was a strong positive correlation between the lipid peroxidation and protein oxidation levels. Our results call attention to the need to consider the pro-oxidative capacity of antipsychotic drugs per se and their potential to disturb the oxidative homeostasis in the brain during long-term medication for psychiatric diseases.

Mitochondria of intestinal epithelial cells in depression: Are they at a crossroads of gut-brain communication?

The role of gut dysbiosis in depression is well established. However, recent studies have shown that gut microbiota is regulated by intestinal epithelial cell (IEC) mitochondria, which has yet to receive much attention. This review summarizes the recent developments about the critical role of IEC mitochondria in actively maintaining gut microbiota, intestinal metabolism, and immune homeostasis. We propose that IEC mitochondrial dysfunction alters gut microbiota composition, participates in cell fate, mediates oxidative stress, activates the peripheral immune system, causes peripheral inflammation, and transmits peripheral signals through the vagus and enteric nervous systems. These pathological alterations lead to brain inflammation, disruption of the blood-brain barrier, activation of the hypothalamic-pituitary-adrenal axis, activation of microglia and astrocytes, induction of neuronal loss, and ultimately depression. Furthermore, we highlight the prospect of treating depression through the mitochondria of IECs. These new findings suggest that the mitochondria of IECs may be a newly found important factor in the pathogenesis of depression and represent a potential new strategy for treating depression.

Association between urinary 2-hydroxyethyl mercapturic acid and dyslexia among school-aged children

Ethylene oxide is commonly used in industrial synthesis and medical disinfection. It is a known human carcinogen and has neurotoxicity. However, the association between ethylene oxide exposure and neurodevelopmental disorders remains unclear. This study aimed to evaluate the association between urinary concentrations of 2-hydroxyethyl mercapturic acid (HEMA; metabolite of ethylene oxide) and dyslexia among school-aged children. A total of 355 dyslexic children and 390 controls from three cities in China were enrolled in this case-control study from November 2017 to December 2020. Urinary HEMA was detected in 100% of the urine samples, suggesting widespread exposure to ethylene oxide in the children. Notably, the children with dyslexia had higher concentrations of urinary HEMA compared to the controls (geometric mean: 2.92 vs. 2.47 ng/mL) (P = 0.004). In the multivariable-adjusted model, urinary concentrations of HEMA were significantly associated with dyslexia risk. The individuals within the highest HEMA concentration demonstrated a 1.97-fold increased odds of dyslexia compared to those within the lowest quartile (95% confidence interval: 1.20-3.23). Thus, these findings suggested the possible link between HEMA levels and the risk of dyslexia. Further studies are warranted to validate this finding and illustrate the underlying mechanism.

Establishment of an assistive diagnostic model for schizophrenia with oxidative stress biomarkers

Objective: In this study, alterations in oxidative stress-related indicators were evaluated in drug-naïve, first-episode schizophrenia (SCZ) patients, and the effectiveness of blood serum glucose, superoxide dismutase (SOD), bilirubin in the objective assistive diagnosis of schizophrenia was explored. Materials and methods: We recruited 148 drug-naïve, first-episode SCZ patients and 97 healthy controls (HCs). Blood biochemical indexes including blood glucose, SOD, bilirubin and homocysteine (HCY) in participants were measured, the indexes were compared between patients with SCZ and HCs. The assistive diagnostic model for SCZ was established on the basis of the differential indexes. Results: In SCZ patients, the blood serum levels of glucose, total (TBIL), indirect bilirubin (IBIL) and homocysteine (HCY) were significantly higher than those in HCs (p < 0.05), and the serum levels of SOD were significantly lower than those in HCs (p < 0.05). There was a negative correlation between SOD with the general symptom scores and total scores of PANSS. After risperidone treatment, the levels of uric acid (UA) and SOD tended to increase in patients with SCZ (p = 0.02, 0.19), and the serum levels of TBIL and HCY tended to decrease in patients with SCZ (p = 0.78, 0.16). The diagnostic model based on blood glucose, IBIL and SOD was internally cross-validated, and the accuracy was 77%, with an area under the curve (AUC) of 0.83. Conclusion: Our study demonstrated an oxidative state imbalance in drug-naïve, first-episode SCZ patients, which might be associated with the pathogenesis of the disease. Our study proved that glucose, IBIL and SOD may be potential biological markers of schizophrenia, and the model based on these markers can assist the early objective and accurate diagnosis of schizophrenia.

Identification of a Hypoxia-Related Signature as Candidate Detector for Schizophrenia Based on Genome-Wide Gene Expression

INTRODUCTION

Schizophrenia (SCZ), a severe neuropsychiatric disorder with high genetic susceptibility, has high rates of misdiagnosis due to the unavoidably subjective factors and heterogeneous clinical presentations. Hypoxia has been identified as an importantly risk factor that participates in the development of SCZ. Therefore, development of a hypoxia-related biomarker for SCZ diagnosis is promising. Therefore, we dedicated to develop a biomarker that could contribute to distinguishing healthy controls and SCZ patients.

METHODS

GSE17612, GSE21935, and GSE53987 datasets, consisting of 97 control samples and 99 SCZ samples, were involved in our study. The hypoxia score was calculated based on the single-sample gene-set enrichment analysis using the hypoxia-related differentially expressed genes to quantify the expression levels of these genes for each SCZ patient. Patients in high-score groups were defined if their hypoxia score was in the upper half of all hypoxia scores and patients in low-score groups if their hypoxia score was in the lower half. GSEA was applied to detect the functional pathway of these differently expressed genes. CIBERSORT algorithm was utilized to evaluate the tumor-infiltrating immune cells of SCZ patients.

RESULTS

In this study, we developed and validated a biomarker consisting of 12 hypoxia-related genes that could distinguish healthy controls and SCZ patients robustly. We found that the metabolism reprogramming might be activated in the patient with high hypoxia score. Finally, CIBERSORT analysis illustrated that lower composition of naive B cells and higher composition of memory B cells might be observed in low-score groups of SCZ patients.

CONCLUSION

These findings revealed that the hypoxia-related signature was acceptable as a detector for SCZ, providing further insight into effective diagnosis and treatment strategies for SCZ.

Transient Receptor Potential (TRP) Channels in Pain, Neuropsychiatric Disorders, and Epilepsy

Pharmacomodulation of membrane channels is an essential topic in the study of physiological conditions and disease status. Transient receptor potential (TRP) channels are one such family of nonselective cation channels that have an important influence. In mammals, TRP channels consist of seven subfamilies with a total of twenty-eight members. Evidence shows that TRP channels mediate cation transduction in neuronal signaling, but the full implication and potential therapeutic applications of this are not entirely clear. In this review, we aim to highlight several TRP channels which have been shown to mediate pain sensation, neuropsychiatric disorders, and epilepsy. Recent findings suggest that TRPM (melastatin), TRPV (vanilloid), and TRPC (canonical) are of particular relevance to these phenomena. The research reviewed in this paper validates these TRP channels as potential targets of future clinical treatment and offers patients hope for more effective care.

Mechanisms underpinning Carpolobia lutea G. Don ethanol extract's neurorestorative and antipsychotic-like activities in an NMDA receptor antagonist model of schizophrenia

ETHNOPHARMACOLOGICAL RELEVANCE

Persistent ketamine insults to the central nervous system block NMDA receptors and disrupt putative neurotransmission, oxido-nitrosative, and inflammatory pathways, resulting in schizophrenia-like symptoms in animals. Previously, the ethnomedicinal benefits of Carpolobia lutea against insomnia, migraine headache, and insanity has been documented, but the mechanisms of action remain incomplete.

AIM OF THE STUDY

Presently, we explored the neuro-therapeutic role of Carpolobia lutea ethanol extract (C. lutea) in ketamine-induced schizophrenia-like symptoms in mice.

MATERIALS AND METHODS

Sixty-four male Swiss (22 ± 2 g) mice were randomly assigned into eight groups (n = 8/group) and exposed to a reversal ketamine model of schizophrenia. For 14 days, either distilled water (10 mL/kg; p.o.) or ketamine (20 mg/kg; i.p.) was administered, following possible reversal treatments with C. lutea (100, 200, 400, and 800 mg/kg; p.o.), haloperidol (1 mg/kg, p.o.), or clozapine (5 mg/kg; p.o.) beginning on days 8-14. During the experiment, a battery of behavioral characterizations defining schizophrenia-like symptoms were obtained using ANY-maze software, followed by neurochemical, oxido-inflammatory and histological assessments in the mice brains.

RESULTS

A 7-day reversal treatment with C. lutea reversed predictors of positive, negative and cognitive symptoms of schizophrenia. C. lutea also mitigated ketamine-induced neurochemical derangements as evidenced by modulations of dopamine, glutamate, norepinephrine and serotonin neurotransmission. Also, the increased acetylcholinesterase activity, malondialdehyde nitrite, interleukin-6 and tumor necrosis-factor-α concentrations were reversed by C. lutea accompanied with elevated levels of catalase, superoxide dismutase and reduced glutathione. Furthermore, C. lutea reversed ketamine-induced neuronal alterations in the prefrontal cortex, hippocampus and cerebellum sections of the brain.

CONCLUSION

These findings suggest that C. lutea reverses the cardinal symptoms of ketamine-induced schizophrenia in a dose-dependent fashion by modulating the oxido-inflammatory and neurotransmitter-related mechanisms.

Dietary methionine restriction improves gut microbiota composition and prevents cognitive impairment in D-galactose-induced aging mice

Dietary methionine restriction (MR) has been shown to delay aging and ameliorate age-related cognitive impairments. We hypothesized that changes in the gut microbiota may mediate these effects. To test this hypothesis, ICR mice subcutaneously injected with 150 mg kg^-1 day^-1D-galactose were fed a normal (0.86% methionine) or an MR (0.17% methionine) diet for 2 months. Multiple behavioral experiments were performed, and the gut microbiota composition, metabolite profiles related to short-chain fatty acids (SCFAs) in the feces, and indicators related to the redox and inflammatory states in the hippocampus were further analyzed. Our results indicated that MR alleviated cognitive impairment (including non-spatial memory deficits, working memory deficits, and hippocampus-dependent spatial memory deficits) and anxiety-like behavior in D-Gal-induced aging mice. Furthermore, MR increased the abundance of putative SCFA-producing bacteria such as Lachnospiraceae, Turicibacter, Roseburia, Ruminococcaceae_UCG-014, Intestinimonas, Rikenellaceae, Tyzzerella, and H₂S-producing bacteria such as Desulfovibrio in feces. Moreover, MR reversed and normalized the levels of intestinal SCFAs (acetate, propionate, and butyrate) and important intermediate metabolites of the SCFAs (pyruvate, lactate, malate, fumarate, and succinate), abolished aging-induced oxidative stress and inflammatory responses, increased the levels of H₂S in the plasma and hippocampus, and selectively modulated the expression of multiple learning- and memory-related genes in the hippocampus. These findings suggest that MR improved the gut microbiota composition and SCFA production and alleviated oxidative stress and inflammatory responses in the hippocampus, which might prevent cognitive impairment in D-galactose-induced aging mice.

Oxidative Stress and Psychiatric Disorders: Evidence from the Bidirectional Mendelian Randomization Study

Observational studies have shown that oxidative stress is highly related to psychiatric disorders, while its cause−effect remains unclear. To this end, a Mendelian randomization study was performed to investigate the causal relationship between oxidative stress and psychiatric disorders. On the one hand, all causal effects of oxidative stress injury biomarkers (OSIB) on psychiatric disorders were not significant (p > 0.0006), while the findings suggested that part of OSIB was nominally associated with the risk of psychiatric disorders (causal OR of uric acid (UA), 0.999 for bipolar disorder (BD), and 1.002 for attention-deficit/hyperactivity disorder (ADHD); OR of catalase was 0.903 for anorexia nervosa (AN); OR of albumin was 1.162 for autism; p < 0.05). On the other hand, major depressive disorder (MDD) was significantly associated with decreased bilirubin (p = 2.67 × 10−4); ADHD was significantly associated with decreased ascorbate (p = 4.37 × 10−5). Furthermore, there were also some suggestively causal effects of psychiatric disorders on OSIB (BD on decreased UA and increased retinol; MDD on increased UA and decreased ascorbate; schizophrenia on decreased UA, increased retinol and albumin; ADHD on increased UA, and decreased catalase, albumin, and bilirubin; AN on decreased UA). This work presented evidence of potential causal relationships between oxidative stress and psychiatric disorders.

Paeoniflorin Rescued MK-801-Induced Schizophrenia-Like Behaviors in Mice via Oxidative Stress Pathway

Schizophrenia (SCZ) affects approximately 1% population worldwide, and the first-line antipsychotics have partial reactivity or non-reactivity with side effects. Therefore, there is an urgent need to find more effective drugs. Paeoniflorin (PF) is the main effective component of traditional Chinese medicine from white peony, red peony and peony bark, which acts as a neuroprotective agent. The purpose of this study was to investigate whether PF can rescue MK-801 induced schizophrenia-like behavior in mice. Our results demonstrated that intragastric administration of PF ameliorated MK-801 induced schizophrenia–like behaviors in mice as demonstrated by prepulse inhibition of acoustic startle response, fear conditioning test for memory and open field test for activity. In contrast, the first-line antipsychotics-olanzapine reversed the prepulse inhibition deficits and hyperactivities, but not memory deficits, in the model mice. Further analysis showed that PF reduced oxidative stress in the MK-801-treated mice, as evidenced by the increased superoxide dismutase levels and decreased malondialdehyde levels in the blood of the model mice. In addition, PF treatment inhibited the expression of the apoptotic protein Bax and restored the expression of tyrosine hydroxylase in the brains of the model mice. in vitro data indicated that PF protected against oxidative stress induced neurotoxicity in the primary cultured hippocampal neurons. In conclusion, our results were the first to provide evidence that PF rescued schizophrenia-like behaviors (both positive symptoms and cognitive impairments) in rodents through oxidative stress pathway, and therefore provide a novel strategy for treatment of SCZ. However, more pre-clinical and clinical research are needed to translate the present findings into clinics for a treatment of schizophrenia.

Cinnamic Acid Improved Lipopolysaccharide-Induced Depressive-Like Behaviors by Inhibiting Neuroinflammation and Oxidative Stress in Mice

AIM

Recent evidence indicates that neuroinflammation and oxidative stress play vital roles in the pathological process of major depressive disorder (MDD). Cinnamic acid (CA), a naturally occurring organic acid, has been reported to ameliorate neuroinflammation and oxidative stress for treatment of diabetes-related memory deficits. Here, we explored whether CA pretreatment ameliorated lipopolysaccharide (LPS)-induced depressive-like behaviors in mice by suppressing neuroinflammation and by improving oxidative stress status.

METHODS

The mice were treated with CA, vehicle, or fluoxetine as a positive control. After 14 days, LPS (1 mg/kg, i.p.) or saline was administered. The depression-like behaviors were examined by the sucrose preference test (SPT), the forced swimming test (FST), and the tail suspension test (TST). Furthermore, the levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), and brain-derived neurotrophic factor (BDNF) in the hippocampus and cortex of mice were assayed.

RESULTS

Our results demonstrated that CA pretreatment at the doses of 100 and 200 mg/kg significantly attenuated depressive-like behaviors in the TST, FST, and SPT. In addition, not only the upregulation of pro-inflammatory cytokines (IL-6 and TNF-α) but also oxidative stress parameters including SOD, GSH, and MDA in the hippocampus and cortex of mice treated with LPS were dramatically improved by CA pretreatment. Finally, CA pretreatment strikingly ameliorated the downregulation of BDNF induced by LPS in the hippocampus and cortex of mice.

CONCLUSION

Our results indicated that CA may have therapeutic potential for MDD treatment through attenuating the LPS-induced inflammation and oxidative stress along with significant improvement of BDNF impairment.

Possible involvement of l-arginine-nitric oxide pathway in the antidepressant activity of Auraptene in mice

Background

Depression is one of the most common mental illnesses worldwide. Nitric oxide (NO) is involved in the pathophysiology of depression. Auraptene (a coumarin derivative) has been shown to possess pharmacological effects on neurological diseases.

Purpose

The present study aimed to investigate the possible role of the NO pathway in Auraptene antidepressant effects in male mice.

Methods

Behavioral tests were used to assess depression-like behaviors. The mice received Auraptene at 10, 30, and 100 mg/kg, the combination of the sub-effective (ineffective) dose of Auraptene (10 mg/kg) and L-NAME, and the combination of the effective dose of Auraptene (30 mg/kg) and L-arginine. Finally, OFT, TST, FST, brain, serum MDA level, antioxidant capacity, hippocampus, and serum NO level were measured.

Results

The data analysis showed that Auraptene (30 mg/kg) improved depression-like behaviors. Auraptene (30 mg/kg) also significantly reduced serum NO levels (P < 0.05) and significantly increased serum MDA (10 mg/kg, P < 0.05). Auraptene at 30 mg/kg also increased serum antioxidant capacity (P < 0.01). Co-administration of L-NAME and the sub-effective dose of Auraptene enhanced the effects of Auraptene. However, co-administration of the effective dose of Auraptene and L-arginine reduced the impacts of Auraptene.

Conclusions

The results showed that Auraptene causes antidepressant effects in a dose-dependent manner and acts as a prooxidant at 100 mg/kg, and exacerbates oxidative stress. The antidepressant effects of this active molecule are exerted by reducing the NO level in the hippocampus and serum, increasing the antioxidant capacity, and reducing the MDA level in the serum.

Edaravone ameliorates depressive and anxiety-like behaviors via Sirt1/Nrf2/HO-1/Gpx4 pathway

Background

The inflammation and oxidative stress (OS) have been considered crucial components of the pathogenesis of depression. Edaravone (EDA), a free radical scavenger, processes strong biological activities including antioxidant, anti-inflammatory and neuroprotective properties. However, its role and potential molecular mechanisms in depression remain unclear. The present study aimed to investigate the antidepressant activity of EDA and its underlying mechanisms.

Methods

A chronic social defeat stress (CSDS) depression model was performed to explore whether EDA could produce antidepressant effects. Behaviors tests were carried out to examine depressive, anxiety-like and cognitive behaviors including social interaction (SI) test, sucrose preference test (SPT), open field test (OFT), elevated plus maze (EPM), novel object recognition (NOR), tail suspension test (TST) and forced swim test (FST). Hippocampal and medial prefrontal cortex (mPFC) tissues were collected for Nissl staining, immunofluorescence, targeted energy metabolomics analysis, enzyme-linked immunosorbent assay (ELISA), measurement of MDA, SOD, GSH, GSH-PX, T-AOC and transmission electron microscopy (TEM). Western blotting (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) detected the Sirt1/Nrf2/HO-1/Gpx4 signaling pathway. EX527, a Sirt1 inhibitor and ML385, a Nrf2 inhibitor were injected intraperitoneally 30 min before EDA injection daily. Knockdown experiments were performed to determine the effects of Gpx4 on CSDS mice with EDA treatment by an adeno-associated virus (AAV) vector containing miRNAi (Gpx4)–EGFP infusion.

Results

The administrated of EDA dramatically ameliorated CSDS-induced depressive and anxiety-like behaviors. In addition, EDA notably attenuated neuronal loss, microglial activation, astrocyte dysfunction, oxidative stress damage, energy metabolism and pro-inflammatory cytokines activation in the hippocampus (Hip) and mPFC of CSDS-induced mice. Further examination indicated that the application of EDA after the CSDS model significantly increased the protein expressions of Sirt1, Nrf2, HO-1 and Gpx4 in the Hip. EX527 abolished the antidepressant effect of EDA as well as the protein levels of Nrf2, HO-1 and Gpx4. Similarly, ML385 reversed the antidepressant and anxiolytic effects of EDA via decreased expressions of HO-1 and Gpx4. In addition, Gpx4 knockdown in CSDS mice abolished EDA-generated efficacy on depressive and anxiety-like behaviors.

Conclusion

These findings suggest that EDA possesses potent antidepressant and anxiolytic properties through Sirt1/Nrf2/HO-1/Gpx4 axis and Gpx4-mediated ferroptosis may play a key role in this effect.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02400-6.

Neuroprotective Effects of Omentin-1 Against Cerebral Hypoxia/Reoxygenation Injury via Activating GAS6/Axl Signaling Pathway in Neuroblastoma Cells

Ischemic stroke is characterized by insufficient blood supply to brain tissue and is associated with increased morbidity and mortality in adults worldwide. Growth arrest-specific protein 6 (GAS6) is a vitamin K-dependent protein and is widely expressed in the central nervous system. The biological functions of GAS6 are mediated by the interaction with TAM (Tyro3, Axl and Mertk) receptors, including cell survival and proliferation, immune regulation and apoptosis. Omentin-1, also known as intelectin-1 (ITLN-1), is a novel adipocytokine that is involved in a variety of biological events, such as insulin resistance, endothelial dysfunction, programmed cell death and metabolic disorders. Our previous study has found that omentin-1 act as a novel regulator of vascular and anti-apoptotic response in cerebral ischemia. However, the specific molecular mechanism of omentin-1’s protective effect on cerebral ischemia-reperfusion injury (IRI) is still unclear. First, the toxicity of recombinant human omentin-1 (rh-omentin) was assessed and a safe concentration was chosen for the next experiments. Then, rh-omentin exerted neuroprotection against hypoxia/reoxygenation (H/R) injury in N2a cells, indicated by increased cell viability, decreased LDH, ROS generation, and cell apoptotic rate. Furthermore, the similar protective effect was observed in omentin-1 overexpression cells constructed by lentivirus transfection. Rh-omentin could also inhibit H/R-induced apoptotic molecules, oxidative stress molecules, and GAS6/Axl signaling molecules which as evidence by increased omentin-1, GAS6, Axl, p-Axl, NQO1, HO-1, Nrf2, Bcl2 and decreased Bax expressions. However, GAS6 siRNA could reverse rh-omentin-induced neuroprotection and the levels of these molecules mentioned above. In conclusion, these findings suggest that omentin-1 treatment exerts neuroprotection against H/R injury partly via activating GAS6/Axl signaling at least. Therefore, these finding may favor omentin-1 a potential neuroprotective drug candidate to alleviate ischemia-reperfusion injury in clinic.

Present and future antipsychotic drugs: a systematic review of the putative mechanisms of action for efficacy and a critical appraisal under a translational perspective

Antipsychotics represent the mainstay of schizophrenia pharmacological therapy, and their role has been expanded in the last years to mood disorders treatment. Although introduced in 1952, many years of research were required before an accurate picture of how antipsychotics work began to emerge. Despite the well-recognized characterization of antipsychotics in typical and atypical based on their liability to induce motor adverse events, their main action at dopamine D2R to elicit the "anti-psychotic" effect, as well as the multimodal action at other classes of receptors, their effects on intracellular mechanisms starting with receptor occupancy is still not completely understood. Significant lines of evidence converge on the impact of these compounds on multiple molecular signaling pathways implicated in the regulation of early genes and growth factors, dendritic spine shape, brain inflammation, and immune response, tuning overall the function and architecture of the synapse. Here we present, based on PRISMA approach, a comprehensive and systematic review of the above mechanisms under a translational perspective to disentangle those intracellular actions and signaling that may underline clinically relevant effects and represent potential targets for further innovative strategies in antipsychotic therapy.

Altered responsiveness of the antioxidant system in chronically stressed animals: modulation by chronic lurasidone treatment

RATIONALE

Although the occurrence of stressful events is very common during life, their impact may be different depending on the experience severity and duration. Specifically, acute challenges may trigger adaptive responses and even improve the individual's performance. However, such a physiological positive coping can only take place if the underlying molecular mechanisms are properly functioning. Indeed, if these systems are compromised by genetic factors or previous adverse conditions, the response set in motion by an acute challenge may be maladaptive and even cause the insurgence or the relapse of stress-related psychiatric disorders.

OBJECTIVES

On these bases, we evaluated in the rat brain the role of the antioxidant component of the redox machinery on the acute stress responsiveness and its modulation by potential detrimental or beneficial events.

METHODS

The expression of several antioxidant enzymes was assessed in different brain areas of adult male rats exposed to acute stress 3 weeks after a chronic immobilization paradigm with or without a concomitant treatment with the antipsychotic lurasidone.

RESULTS

The acute challenge was able to trigger a marked antioxidant response that, despite the washout period, was impaired by the previous adverse experience and restored by lurasidone in an anatomical-specific manner.

CONCLUSIONS

We found that a working antioxidant machinery takes part in acute stress response and may be differentially affected by other experiences. Given the essential role of stress responsiveness in almost every life process, the identification of the underlying mechanisms and their potential pharmacological modulation add further translational value to our data.

Investigation of the protective effect of resveratrol in an MK-801-induced mouse model of schizophrenia

Increasing evidence supports the view that oxidative stress and brain demyelination play an important role in the pathogenesis of schizophrenia. Resveratrol is a powerful antioxidant with neuroprotective effects. This study aimed to assess the effect of resveratrol on schizophrenia-like behaviors and possible brain demyelination induced by MK-801, an N-methyl-D-aspartate glutamate receptor antagonist, and the underlying neuroprotective mechanism. Resveratrol (40 mg/kg/day/, intraperitoneal) was administered to mice for 14 days. MK-801 (1 mg/kg/day, intraperitoneal) was injected into the mice 4 h after the resveratrol administration for 14 days. The open-field and elevated-plus maze tests were performed to detect behavior changes on the 15th day. Following the behavioral tests, the expression of the myelin basic protein (MBP) was measured with the real-time PCR (RT-PCR) method, while total oxidant capacity (TOS) and total antioxidant capacity (TAS), which are the biomarkers of oxidative damage, were measured with the ELISA method. Hematoxylin-eosin staining was also used to identify stereological and pathological changes in the brain. According to the results obtained, this study showed for the first time that resveratrol prevented glial cell infiltration induced in the brain by MK-801 and shrinkage of nerve cell nuclei in the hippocampus and corpus callosum. However, the resveratrol administrations did not correct behavioral disorders and demyelination of schizophrenia. Although resveratrol partially prevented oxidative damage in the brain in the mice that were injected with MK-801, it was determined that this effect was not statistically significant. These results showed that resveratrol administration partially protects tissues against MK-801-induced neurodegeneration, and resveratrol may be used in combination with different antioxidants or at different doses in future studies.

Non-cell-autonomous OTX2 transcription factor regulates anxiety-related behavior in the mouse

The OTX2 homeoprotein transcription factor is expressed in the dopaminergic neurons of the ventral tegmental area, which projects to limbic structures controlling complex behaviors. OTX2 is also produced in choroid plexus epithelium, from which it is secreted into cerebrospinal fluid and transferred to limbic structure parvalbumin interneurons. Previously, adult male mice subjected to early-life stress were found susceptible to anxiety-like behaviors, with accompanying OTX2 expression changes in ventral tegmental area or choroid plexus. Here, we investigated the consequences of reduced OTX2 levels in Otx2 heterozygote mice, as well as in Otx2+/AA and scFvOtx2tg/0 mouse models for decreasing OTX2 transfer from choroid plexus to parvalbumin interneurons. Both male and female adult mice show anxiolysis-like phenotypes in all three models. In Otx2 heterozygote mice, we observed no changes in dopaminergic neuron numbers and morphology in ventral tegmental area, nor in their metabolic output and projections to target structures. However, we found reduced expression of parvalbumin in medial prefrontal cortex, which could be rescued in part by adult overexpression of Otx2 specifically in choroid plexus, resulting in increased anxiety-like behavior. Taken together, OTX2 synthesis by the choroid plexus followed by its secretion into the cerebrospinal fluid is an important regulator of anxiety-related phenotypes in the mouse.

Short-chain fatty acids as modulators of redox signaling in health and disease

Short-chain fatty acids (SCFAs), produced by colonic bacteria and obtained from the diet, have been linked to beneficial effects on human health associated with their metabolic and signaling properties. Their physiological functions are related to their aliphatic tail length and dependent on the activation of specific membrane receptors. In this review, we focus on the mechanisms underlying SCFAs mediated protection against oxidative and mitochondrial stress and their role in regulating metabolic pathways in specific tissues. We critically evaluate the evidence for their cytoprotective roles in suppressing inflammation and carcinogenesis and the consequences of aging. The ability of these natural compounds to induce signaling pathways, involving nuclear erythroid 2-related factor 2 (Nrf2), contributes to the maintenance of redox homeostasis under physiological conditions. SCFAs may thus serve as nutritional and therapeutic agents in healthy aging and in vascular and other diseases such as diabetes, neuropathologies and cancer.

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SCFAs are a link between the microbiota, redox signaling and host metabolism.

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SCFAs modulate Nrf2 redox signaling through specific free fatty acid receptors.

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Butyrate induces epigenetic regulation and/or Nrf2 nuclear translocation.

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Butyrate and propionate protect the blood-brain barrier by facilitating docosahexaenoic acid transport.

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Regulation of redox homeostasis by SCFAs supports their potential as therapeutic nutrients in health and disease.

New insights into neuropeptides regulation of immune system and hemopoiesis: effects on hematologic malignancies

Several neurotransmitters and neuropeptides were reported to join to or to cooperate with different cells of the immune system, bone marrow, and peripheral cells and numerous data support that neuroactive molecules might control immune system activity and hemopoiesis operating on lymphoid organs, and the primary hematopoietic unit, the hematopoietic niche. Furthermore, many compounds seem to be able to take part to the leukemogenesis and lymphomagenesis process, and in the onset of multiple myeloma. In this review, we will assess the possibility that neurotransmitters and neuropeptides may have a role in the onset of haematological neoplasms, may affect the response to treatment or may represent a useful starting point for a new therapeutic approach. More in vivo investigations are needed to evaluate neuropeptide's role in haematological malignancies and the possible utilization as an antitumor therapeutic target. Comprehending the effect of the pharmacological administration of neuropeptide modulators on hematologic malignancies opens up new possibilities in curing clonal hematologic diseases to achieve more satisfactory outcomes.

Effect of m-Trifluoromethyl-diphenyl diselenide on the Pain-Depression Dyad Induced by Reserpine: Insights on Oxidative Stress, Apoptotic, and Glucocorticoid Receptor Modulation

Chronic pain and depression often coexist sharing common pathological mechanisms, and available analgesics and antidepressants have demonstrated limited clinical efficacy. Evidence has demonstrated that neuronal oxidative stress, apoptosis, and also glucocorticoid receptor dysregulation facilitate the occurrence and development of both chronic pain and depression. This study evaluated the effect of the organoselenium compound m-trifluoromethyl-diphenyl diselenide [(m-CF₃-PhSe)₂] in the pain-depression comorbidity induced by reserpine. Mice were treated with reserpine 0.5 mg/kg for 3 days (intraperitoneal, once a day), and in the next 2 days, they were treated with (m-CF₃-PhSe)₂ 10 mg/kg (intragastric, once a day). Thirty minutes after the last administration of (m-CF₃-PhSe)₂, mice were subjected to the behavioral testing. (m-CF₃-PhSe)₂ treatment reverted the reserpine-increased thermal hyperalgesia and depressive-like behavior observed in the hot-plate test and forced swimming test, respectively. Reserpine provoked a decrease of crossings and rearings in the open-field test, while (m-CF₃-PhSe)₂ presented a tendency to normalize these parameters. Reserpine and/or (m-CF₃-PhSe)₂ treatments did not alter the locomotor activity of mice observed in the rota-rod test. These effects could be related to modulation of oxidative stress, apoptotic pathway, and glucocorticoid receptors, once (m-CF₃-PhSe)₂ normalized thiobarbituric acid reactive substances and 4-hydroxynonenal modified protein levels, markers of lipoperoxidation, poly(ADP-ribose) polymerase cleaved/total ratio, and glucocorticoid receptor levels increased by reserpine in the hippocampus. Considering that pain-depression dyad is a complex state of difficult treatment, this organoselenium compound could raise as an interesting alternative to treat pain-depression condition.

Therapeutic Effect and Mechanisms of Essential Oils in Mood Disorders: Interaction between the Nervous and Respiratory Systems

Essential oils (EOs) are extracted from plants and contain active components with therapeutic effects. Evidence shows that various types of EOs have a wide range of health benefits. In our previous studies, the potential of lavender EO for prevention and even treatment of depression and anxiety symptoms was demonstrated. The favourable outcomes may be due to multiple mechanisms, including the regulation of monoamine level, the induction of neurotrophic factor expression, the regulation of the endocrine system and the promotion of neurogenesis. The molecules of EOs may reach the brain and exert an effect through two distinctive pathways, namely, the olfactory system and the respiratory system. After inhalation, the molecules of the EOs would either act directly on the olfactory mucosa or pass into the respiratory tract. These two delivery pathways suggest different underlying mechanisms of action. Different sets of responses would be triggered, such as increased neurogenesis, regulation of hormonal levels, activation of different brain regions, and alteration in blood biochemistry, which would ultimately affect both mood and emotion. In this review, we will discuss the clinical effects of EOs on mood regulation and emotional disturbances as well as the cellular and molecular mechanisms of action. Emphasis will be put on the interaction between the respiratory and central nervous system and the involved potential mechanisms. Further evidence is needed to support the use of EOs in the clinical treatment of mood disturbances. Exploration of the underlying mechanisms may provide insight into the future therapeutic use of EO components treatment of psychiatric and physical symptoms.

Reduction in TNF alpha and oxidative stress by liraglutide: Impact on ketamine-induced cognitive dysfunction and hyperlocomotion in rats

BACKGROUND

Diabetes and psychotic disorders are occasionally comorbid. Possible pathophysiologies linking these disorders include inflammation and oxidative stress. Glucagon like peptide-1 (GLP-1) agonists modulate glucose metabolism and may exert neuroprotective effects via central GLP-1 receptors.

AIM OF THE WORK

To explore the effects of GLP-1 agonist, liraglutide, on ketamine-induced hyper-locomotion and cognitive dysfunction and the associated inflammation and oxidative stress in normoglycemic and diabetic rats.

METHODS

Rats were divided into: Chow fed (non-diabetic) and high fat diet fed/STZ (diabetic) groups: I. non-diabetic/control, non-diabetic/liraglutide, non-diabetic/ketamine, non-diabetic/ketamine/liraglutide groups. II. diabetic/control, diabetic/liraglutide, diabetic/ketamine and diabetic/ketamine/liraglutide groups. Hyperlocomotion and cognitive dysfunction were assessed using open field and water maze tests. Biochemical parameters were measured in serum and hippocampus.

RESULTS

Ketamine induced hyperlocomotion and cognitive dysfunction, with hippocampal histopathological changes. Increase in tumour necrosis factor (TNF)-alpha and oxidative stress and reduction in brain-derived neurotrophic factor (BDNF) were noted. These changes were augmented in diabetic compared to non-diabetic rats. Liraglutide significantly improved hyperlocomotion, and cognitive dysfunction and hippocampal histopathological changes in non-diabetic and diabetic rats. Improvement in glucose homeostasis, reduction in TNF alpha and malondialdehyde, and increase in glutathione and BDNF were observed in serum and hippocampus.

CONCLUSION

Beneficial effects of liraglutide on ketamine-induced hyperlocomotion and cognitive dysfunction are associated with reduction in TNF alpha and oxidative stress. Since effects of liraglutide occurred in diabetic and non-diabetic rats, glycemic and non-glycemic effects (via central GLP-1 receptors) might be involved. Targeting oxidative stress and inflammation by GLP-1 agonists, may be a promising approach in psychotic patients with diabetes.

Psychotherapy with Music Intervention Improves Anxiety, Depression and the Redox Status in Breast Cancer Patients Undergoing Radiotherapy: A Randomized Controlled Clinical Trial

The aim of this study was to assess the effects of psychotherapy with music intervention (PMI) on anxiety, depression, redox status, and inflammation in breast cancer patients undergoing radiotherapy (RT). This monocentric randomized clinical trial recruited 60 patients who had a breast cancer operation and were undergoing postoperative RT. Eligible patients were randomized (1:1) in two groups: the control group (CG) received treatment as usual (n = 30), i.e., RT alone; the intervention group (PMI) received RT and psychotherapy with music intervention (n = 30), which was delivered in a group setting. Five patients were excluded after randomization. Assessments were performed at baseline (T0), at the end of RT (T1), and three months after the end of RT (T2). The main objectives of the study were the assessment of anxiety/depression, plasma glutathione (GSH), and thiobarbituric acid reactive substances (TBARS) in the two arms of the study. Our findings revealed a positive effect of PMI on anxiety, depression, resilience, and quality of life. Furthermore, a positive effect of PMI on redox status was found for the first time. Thus, in the PMI group, we found a significant increase of GSH (mean change 2.2 95%, CI 0.7 to 3.7) and a significant reduction of TBARS (mean change -1.1 95%, CI -1.8 to -0.3) at T2 vs. T0.

Determinants of Schizophrenia Endophenotypes Based on Neuroimaging and Biochemical Parameters

Despite extensive research, there is no convincing evidence of a reliable diagnostic biomarker for schizophrenia beyond clinical observation. Disorders of glutamatergic neurotransmission associated with N-methyl-D-aspartate (NMDA) receptor insufficiency, neuroinflammation, and redox dysregulation are the principal common mechanism linking changes in the periphery with the brain, ultimately contributing to the emergence of negative symptoms of schizophrenia that underlie differential diagnosis. The aim of the study was to evaluate the influence of these systems via peripheral and cerebral biochemical indices in relation to the patient's clinical condition. Using neuroimaging diagnostics, we were able to define endophenotypes of schizophrenia based on objective laboratory data that form the basis of a personalized approach to diagnosis and treatment. The two distinguished endophenotypes differed in terms of the quality of life, specific schizophrenia symptoms, and glutamatergic neurotransmission metabolites in the anterior cingulate gyrus. Our results, as well as further studies of the excitatory or inhibitory balance of microcircuits, relating the redox systems on the periphery with the distant regions of the brain might allow for predicting potential biomarkers of neuropsychiatric diseases, including schizophrenia. To the best of our knowledge, our study is the first to identify an objective molecular biomarker of schizophrenia outcome.

The Nrf2 pathway in psychiatric disorders: pathophysiological role and potential targeting

Introduction: All psychiatric disorders exhibit excitotoxicity, mitochondrial dysfunction, inflammation, oxidative stress, and neural damage as their common characteristic. The endogenous nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway is implicated in the defense mechanism against oxidative stress and has a significant role in psychiatric disorders.Areas covered: We explore the role of Nrf2 pathway and its modulators in psychiatric disorders. The literature was searched utilizing various databases such as Embase, Medline, Web of Science, Pub-Med, and Google Scholar from 2010 to 2020. The search included research articles, clinical reports, systematic reviews, and meta-analyses.Expert opinion: Environmental factors and genetic predisposition can be a trigger for the development of psychiatric disorders. Nrf2 downregulates certain inflammatory pathways and upregulates various antioxidant enzymes to maintain a balance. However, its intricate balance with NF-Kβ (Nuclear factor kappa light chain enhancer of activated B cells) and its crosstalk with the transcription factor Nrf2 is critical in severe oxidative stress. Several Nrf2 modulators are now in clinical trials and can help reduce oxidative stress and neuroinflammation. There are immense potential opportunities for these modulators to become a novel therapeutic option.

Oxidative Stress-Related Mechanisms in Schizophrenia Pathogenesis and New Treatment Perspectives

Schizophrenia is recognized to be a highly heterogeneous disease at various levels, from genetics to clinical manifestations and treatment sensitivity. This heterogeneity is also reflected in the variety of oxidative stress-related mechanisms contributing to the phenotypic realization and manifestation of schizophrenia. At the molecular level, these mechanisms are supposed to include genetic causes that increase the susceptibility of individuals to oxidative stress and lead to gene expression dysregulation caused by abnormal regulation of redox-sensitive transcriptional factors, noncoding RNAs, and epigenetic mechanisms favored by environmental insults. These changes form the basis of the prooxidant state and lead to altered redox signaling related to glutathione deficiency and impaired expression and function of redox-sensitive transcriptional factors (Nrf2, NF-κB, FoxO, etc.). At the cellular level, these changes lead to mitochondrial dysfunction and metabolic abnormalities that contribute to aberrant neuronal development, abnormal myelination, neurotransmitter anomalies, and dysfunction of parvalbumin-positive interneurons. Immune dysfunction also contributes to redox imbalance. At the whole-organism level, all these mechanisms ultimately contribute to the manifestation and development of schizophrenia. In this review, we consider oxidative stress-related mechanisms and new treatment perspectives associated with the correction of redox imbalance in schizophrenia. We suggest that not only antioxidants but also redox-regulated transcription factor-targeting drugs (including Nrf2 and FoxO activators or NF-κB inhibitors) have great promise in schizophrenia. But it is necessary to develop the stratification criteria of schizophrenia patients based on oxidative stress-related markers for the administration of redox-correcting treatment.

Drug repositioning for treatment-resistant depression: Hypotheses from a pharmacogenomic study

About 20-30% of patients with major depressive disorder (MDD) develop treatment-resistant depression (TRD) and finding new effective treatments for TRD has been a challenge. This study aimed to identify new possible pharmacological options for TRD. Genes in pathways included in predictive models of TRD in a previous whole exome sequence study were compared with those coding for targets of drugs in any phase of development, nutraceuticals, proteins and peptides from Drug repurposing Hub, Drug-Gene Interaction database and DrugBank database. We tested if known gene targets were enriched in TRD-associated genes by a hypergeometric test. Compounds enriched in TRD-associated genes after false-discovery rate (FDR) correction were annotated and compared with those showing enrichment in genes associated with MDD in the last Psychiatric Genomics Consortium genome-wide association study. Among a total of 15,475 compounds, 542 were enriched in TRD-associated genes (FDR p < .05). Significant results included drugs which are currently used in TRD (e.g. lithium and ketamine), confirming the rationale of this approach. Interesting molecules included modulators of inflammation, renin-angiotensin system, proliferator-activated receptor agonists, glycogen synthase kinase 3 beta inhibitors and the rho associated kinase inhibitor fasudil. Nutraceuticals, mostly antioxidant polyphenols, were also identified. Drugs showing enrichment for TRD-associated genes had a higher probability of enrichment for MDD-associated genes compared to those having no TRD-genes enrichment (p = 6.21e-55). This study suggested new potential treatments for TRD using a in silico approach. These analyses are exploratory only but can contribute to the identification of drugs to study in future clinical trials.

Behavioral and molecular effects of the antipsychotic drug blonanserin in the chronic mild stress model

Psychiatric disorders represent a critical challenge to our society, given their high global prevalence, complex symptomatology, elusive etiology and the variable effectiveness of pharmacological therapies. Recently, there has been a shift in investigating and redefining these diseases by integrating behavioral observations and multilevel neurobiological measures. Accordingly, endophenotype-oriented studies are needed to develop new therapeutic strategies, with the idea of targeting shared symptoms instead of one defined disease. With these premises, here we investigated the therapeutic properties of chronic treatment with the second-generation antipsychotic blonanserin in counteracting the alterations caused by 7 weeks of Chronic Mild Stress (CMS) in the rat. CMS is a well-established preclinical model able to induce depressive and anxiety-like alterations, which are shared by different psychiatric disorders. Our results demonstrated that the antipsychotic treatment normalizes the CMS-induced emotionality deficits, an effect that may be due to its ability in modulating, within the prefrontal cortex, redox mechanisms, a molecular dysfunction associated with several psychiatric disorders. These evidences provide new insights into the therapeutic properties and potential use of blonanserin as well as in its mechanisms of action and provide further support for the role of oxidative stress in the pathophysiology of psychiatric disorders.

Depression and Cardiovascular Disease: The Viewpoint of Platelets

Depression is a major cause of morbidity and low quality of life among patients with cardiovascular disease (CVD), and it is now considered as an independent risk factor for major adverse cardiovascular events. Increasing evidence indicates not only that depression worsens the prognosis of cardiac events, but also that a cross-vulnerability between the two conditions occurs. Among the several mechanisms proposed to explain this interplay, platelet activation is the more attractive, seeing platelets as potential mirror of the brain function. In this review, we dissected the mechanisms linking depression and CVD highlighting the critical role of platelet behavior during depression as trigger of cardiovascular complication. In particular, we will discuss the relationship between depression and molecules involved in the CVD (e.g., catecholamines, adipokines, lipids, reactive oxygen species, and chemokines), emphasizing their impact on platelet activation and related mechanisms.

NRF2 and Primary Cilia: An Emerging Partnership

When not dividing, many cell types target their centrosome to the plasma membrane, where it nucleates assembly of a primary cilium, an antenna-like signaling structure consisting of nine concentric microtubule pairs surrounded by membrane. Primary cilia play important pathophysiological roles in many tissues, their dysfunction being associated with cancer and ciliopathies, a diverse group of congenital human diseases. Several recent studies have unveiled functional connections between primary cilia and NRF2 (nuclear factor erythroid 2-related factor 2), the master transcription factor orchestrating cytoprotective responses to oxidative and other cellular stresses. These NRF2-cilia relationships are reciprocal: primary cilia, by promoting autophagy, downregulate NRF2 activity. In turn, NRF2 transcriptionally regulates genes involved in ciliogenesis and Hedgehog (Hh) signaling, a cilia-dependent pathway with major roles in embryogenesis, stem cell function and tumorigenesis. Nevertheless, while we found that NRF2 stimulates ciliogenesis and Hh signaling, a more recent study reported that NRF2 negatively affects these processes. Herein, we review the available evidence linking NRF2 to primary cilia, suggest possible explanations to reconcile seemingly contradictory data, and discuss what the emerging interplay between primary cilia and NRF2 may mean for human health and disease.