Glutamate and GABA Homeostasis and Neurometabolism in Major Depressive Disorder

Allopregnanolone in the pathogenesis of the psychiatric comorbidities of polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is an endocrine disorder affecting 10-15 % of women of reproductive age, with significant implications for both physical and mental health. Several recent research studies have examined the connection between PCOS and psychiatric disorders; however, the mechanism linking the two is not fully understood. Allopregnanolone is a neurosteroid that modulates GABAA receptors and is naturally affected by the pathophysiology of PCOS. It is thought to play a role in mood disorders, including premenstrual dysphoric disorder and postpartum depression. Recent research has begun to focus on the relationship between PCOS and allopregnanolone. A literature review was conducted using databases, including PubMed, MEDLINE, and Cochrane Library. Keywords included "PCOS," "psychiatric disorders," "allopregnanolone," and "neurosteroids." Articles were selected based on relevance to psychiatric implications of PCOS, with a focus on high-quality, original research studies. Quality assessment of the sources was informed using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) Handbook criteria. The literature review revealed a growing body of evidence suggesting a strong association between PCOS and an increased risk of psychiatric disorders, particularly depression, anxiety, and mood disorders. The role of allopregnanolone, a neurosteroid, was identified as an important factor in this relationship, with some studies indicating its potential impact on mood regulation in PCOS patients. There is a dire need for clinicians to consider the mental health implications of PCOS during diagnosis and management. The integration of psychiatric screening in PCOS management could lead to earlier detection and improved outcomes. Future research should focus on the therapeutic potential of allopregnanolone and other neurosteroids in treating psychiatric disorders associated with PCOS.

Single-Nucleus Transcriptomics of the Nucleus Accumbens Reveals Cell-Type-Specific Dysregulation in Adolescent Macaques with Depressive-Like Behaviors

Adolescent depression is increasingly recognized as a serious mental health disorder with distinct clinical and molecular features. Using single-nucleus RNA sequencing, we identified cell-specific transcriptomic changes in the nucleus accumbens (NAc), particularly in astrocytes, of adolescent macaques exhibiting depressive-like behaviors. The level of diacylglycerol kinase beta was significantly reduced in neurons and glial cells of depressed macaques, while FKBP5 levels increased in glial cells. Disruption of GABAergic synapses and disruption of D-glutamine and D-glutamate metabolism were linked to depressive phenotypes in medium spiny neurons (MSNs) and subtypes of astrocytes. Communication pathways between astrocytes and D1/D2-MSNs were also disrupted, involving factors like bone morphogenetic protein-6 and Erb-B2 receptor tyrosine kinase-4. Bulk transcriptomic and proteomic analyses corroborated these findings, and FKBP5 upregulation was confirmed by qRT-PCR, western blotting, and immunofluorescence in the NAc of rats and macaques with chronic unpredictable mild stress. Our results highlight the specific roles of different cell types in adolescent depression in the NAc, offering potential targets for new antidepressant therapies.

Neurosteroids as emerging therapeutics for treatment-resistant depression: Mechanisms and clinical potential

Treatment-resistant depression (TRD) is a severe and persistent subset of major depressive disorder (MDD) that remains unresponsive to at least two different classes of antidepressants. Given the limitations of conventional treatments, neurosteroids have emerged as promising alternatives due to their rapid and multi-faceted mechanisms of action. Neurosteroids such as allopregnanolone, pregnenolone, and dehydroepiandrosterone (DHEA) modulate key neurotransmitter systems, including gamma-aminobutyric acid (GABA_A) and N-methyl-D-aspartate (NMDA) receptors, enhancing inhibitory transmission and promoting synaptic plasticity. They regulate the hypothalamic-pituitary-adrenal (HPA) axis, mitigating stress-related neurotoxicity and restoring neurochemical balance. Preclinical studies have demonstrated the efficacy of neurosteroids in reversing depressive-like behaviors in rodent models of chronic stress, while clinical trials highlight their potential for rapid and sustained antidepressant effects. Notably, the FDA approval of brexanolone for postpartum depression underscores the translational potential of neurosteroid-based therapies. However, challenges such as limited bioavailability, long-term safety concerns, and regulatory hurdles must be addressed to optimize their clinical application. This review explores the therapeutic potential of neurosteroids in TRD, discussing their mechanisms, clinical evidence, and future directions. The findings support the integration of neurosteroid-based treatments into TRD management, offering new hope for patients unresponsive to conventional antidepressants. This review uniquely highlights the paradigm shift offered by neurosteroids, moving beyond the traditional monoamine hypothesis, and positions them as novel, multi-target therapeutics capable of addressing the complex neurobiology of TRD.

Advancing Depression Management Through Biomarker Discovery with a Focus on Genetic and Epigenetic Aspects: A Comprehensive Study on Neurobiological, Neuroendocrine, Metabolic, and Inflammatory Pathways

Introduction: Depression is a pervasive global health issue, affecting millions worldwide and causing significant disability. Despite its prevalence, current diagnostic and treatment approaches often yield suboptimal outcomes. The complexity of depression, characterized by diverse causes and symptoms, highlights the urgent need for advanced diagnostic tools and personalized therapies. Biomarkers, particularly genetic and epigenetic depression biomarkers, offer promise in uncovering the biological mechanisms underlying depression, potentially revolutionizing its management. Aim: Primary aim: To identify biomarkers associated with depressive disorders, with a focus on genetic and epigenetic biomarkers. Secondary aim: To optimize the current classification of biomarkers associated with different types of depressive disorders, with a focus on genetic and epigenetic biomarkers. Methods: We integrated findings with strategic keywords extracted from relevant studies, conducting a thorough literature review across the Google Scholar, PubMed, and Web of Science databases. Lastly, final reference inclusion had stringent criteria: recent, diverse peer-reviewed articles in English, all study designs, ensuring up-to-date coverage of genetic and epigenetic depression biomarker research. Results: The review reveals the classification of genetic and epigenetic biomarkers in regard to the type of biomarker, the system of the human body it derives from, and the sampling entity. All of the findings show promise in diagnosing depression, with the potential of predicting treatment outcomes and guiding personalized therapeutic approaches. We defined the significant correlations between genetic and epigenetic biomarker profiles and clinical parameters such as symptom severity and treatment response, thereby enhancing diagnostic accuracy and guiding treatment strategies tailored to individual patient needs across diverse depressive subtypes and treatment responses. Conclusion: Identifying biomarkers associated with depressive disorders, with a focus on genetic and epigenetic biomarkers, represents a critical step toward improving diagnostic precision and treatment efficacy. By elucidating the complex biological underpinnings of depression, this study contributes to the development of targeted therapies that address the diverse needs of individuals affected by this debilitating group of disorders. Future research should focus on validating these genetic and epigenetic biomarkers in larger cohorts and clinical trials to facilitate their clinical implementation and enhance patient outcomes.

Intranasal dantrolene nanoparticles inhibit lipopolysaccharide-induced depression and anxiety behavior in mice

This study investigates the therapeutic effectiveness of intranasal dantrolene nanoparticles pretreatment to inhibit lipopolysaccharide (LPS)-induced pathological inflammation and synapse destruction and depressive and anxiety behavior in mice. B6SJLF1/J adult mice were pretreated with intranasal dantrolene nanoparticles (dantrolene: 5mg/kg), daily, Monday to Friday, 5 days per week, for 4 weeks. Then, mice were treated with an intraperitoneal injection of LPS (5mg/kg) for one time. Behavioral tests for depression and anxiety were performed 24 hours after a one-time LPS injection. Biomarkers for pyroptosis-related inflammation cytokines (IL-1β and IL-18) in the blood and brain were measured using enzyme-linked immunosorbent assay (ELISA) and immunoblotting, respectively. The changes of primary proteins activation inflammatory pyroptosis (NLRP3: NLR family pyrin domain containing 3, Caspase-1, N-GSDMD: N terminal protein gasdermin D) and synapse proteins (PSD-95 and synpatin-1) in brains were measured using immunoblotting. Intranasal dantrolene nanoparticles robustly inhibited LPS-induced depression and anxiety behavior. Intranasal dantrolene nanoparticles significantly inhibited LPS-induced pathological elevation of IL-1β and IL-18 in the blood and brain and inhibited LPS-induced activation of pyroptosis. Intranasal dantrolene nanoparticles significantly ameliorated decrease of PSD-95 and synpatin-1 proteins in brains. Thus, intranasal dantrolene nanoparticles have demonstrated neuroprotection against inflammation-mediated depression and anxiety behaviors and should be studied further as a future effective drug treatment of major depression disorder or anxiety psychiatric disorder.

Association of the GRIK4 rs1954787 polymorphism with clinical response in antidepressant-treated depressed patients: results from a prospective cohort and meta-analysis

Major Depressive Disorder (MDD) is the leading cause of disability worldwide. Genetic factors influence the effect of its main treatment option, antidepressant drugs (ATD). The GRIK4 rs1954787(T>C) genetic polymorphism was associated with response following 1-3 months of ATD treatment in some studies, but not others. We aimed to analyze its association with clinical outcomes in a cohort of 6-month ATD-treated patients and meta-analysis. Clinical data were obtained at baseline and after 1 (M1), 3 (M3), and 6 (M6) months of ATD treatment in 390 patients of the METADAP cohort. Mixed-effects models were used to assess the association of the GRIK4 rs1954787 polymorphism with the Hamilton Depression Rating Scale (HDRS) score and response and remission rates across time. Meta-analyses of ATD treatment response were performed with previously meta-analyzed data and METADAP. Compared to C allele carriers at M3 (n = 200), TT homozygotes at M3 (n = 66) had higher HDRS scores (coef = 3.37, 95% CI [1.30-5.54], Padj = 0.0046) and lower remission rates (OR = 0.36, 95% CI [0.16-0.76], Padj = 0.029). At M6, greater differences between TT homozygotes (n = 53) and C allele carriers (n = 152) were observed for HDRS scores (coef = 4.68, 95% CI [2.17-7.18], Padj = 0.00091) and remission rates (OR = 0.26, 95% CI [0.12-0.54], Padj = 0.0016). Meta-analyses of response were significant when comparing C vs T alleles (OR = 1.31, 95% CI [1.06-1.62], P = 0.014) and CC vs TT genotypes (OR = 1.63, 95% CI [1.10-2.38], P = 0.019). Altogether, our results support an association of the GRIK4 rs1954787(T>C) polymorphism with clinical improvement following ATD treatment. This association should be further assessed in other longitudinal studies. Its position within the glutamatergic system may help in understanding the mechanism of ATD action.

Gamma-Aminobutyric Acid Action on Membrane and Electrical Properties of Synaptosomes and Model Lipid Bilayers

Dysfunction of the main inhibitory neurotransmitter gamma-aminobutyric acid (GABA) is the underlying reason behind many neurological disorders including Alzheimer's and Huntington's diseases, autism spectrum disorders, anxiety, depression, hypertension, and cardiovascular diseases, among others. Here, we address neurotransmitter-induced alterations of synaptosomal and model membrane electrical properties for elucidating membrane-related biophysical mechanisms of neurological disorders. We focus on membrane surface characteristics of the pinched off nerve endings synaptosomes, which for decades have been a powerful tool in neurobiology. Microelectrophoretic measurements of GABA-treated negatively charged synaptosomes from rat cerebral cortex reveal lower negative zeta potential as a result of reduced electrical charge on the membrane surface at (1-4 h) after isolation. Conversely, enhancement of the surface parameters of synaptosomes (17-22 h) post isolation is obtained due to additional negatively exposed groups on the surface of the vesicles. The electrical properties of bilayer lipid membranes are probed by electrochemical impedance spectroscopy, reporting as light increase of the membrane electrical capacitance in the presence of GABA, likely related to membrane thinning and dielectric permittivity alterations. The neurotransmitter inhibits sodium-potassium as well as the total ATPase activity and slightly enhances magnesium-ATPase of native synaptic membranes. At low (pM) GABA concentrations the activity of acetylcholinesterase (AChE) in synaptic membranes increases. AChE inhibition is reported at higher GABA concentrations. The relation between the surface electrical properties of cells and the enzymatic activity of brain ATPases and AChE, as examined here, are expected to be helpful in the elucidation of membrane-mediated molecular mechanisms relevant to neurological disorders and conditions.

Intranasal dantrolene nanoparticles inhibit lipopolysaccharide-induced helplessness and anxiety behavior in mice

This study investigates the therapeutic effectiveness of intranasal dantrolene nanoparticles pretreatment to inhibit lipopolysaccharide (LPS)-induced pathological inflammation and synapse destruction and depressive and anxiety behavior in mice. B6SJLF1/J adult mice were pretreated with intranasal dantrolene nanoparticles (dantrolene: 5mg/kg), daily, Monday to Friday, 5 days per week, for 4 weeks. Then, mice were treated with intraperitoneal injection of LPS (5mg/kg) for one time. Behavioral tests for depression and anxiety were performed 24 hours after a one-time LPS injection. Biomarkers for pyroptosis-related inflammation cytokines (IL-1β and IL-18) in blood and brains were measured using enzyme-linked immunosorbent assay (ELISA) and immunoblotting, respectively. The changes of primary proteins activation inflammatory pyroptosis (NLRP3: NLR family pyrin domain containing 3, Caspase-1, N-GSDMD: N terminal protein gasdermin D) and synapse proteins (PSD-95 and synpatin-1) in brains were measured using immunoblotting. Intranasal dantrolene nanoparticles robustly inhibited LPS-induced depression and anxiety behavior. Intranasal dantrolene nanoparticles significantly inhibited LPS-induced pathological elevation of IL-1β and IL-18 in the blood and brain and inhibited LPS induced activation of pyroptosis. Intranasal dantrolene nanoparticles significantly ameliorated decrease of PSD-95 and synpatin-1 proteins in brains. Thus, intranasal dantrolene nanoparticles has demonstrated neuroprotection against inflammation mediated depression and anxiety behaviors and should be studied furthermore as a future effective drug treatment of major depression disorder or anxiety psychiatric disorder.

Activation of zona incerta gamma-aminobutyric acid-ergic neurons alleviates depression-like and anxiety-like behaviors induced by chronic restraint stress

BACKGROUND

Depression is a prevalent affective disorder, but its pathophysiology remains unclear. Dysfunction in the gamma-aminobutyric acid (GABA)-ergic system may contribute to its onset. Recently, antidepressants (e.g., brexanolone, zuranolone) targeting the GABA-A receptor were introduced. The zona incerta (ZI), an inhibitory subthalamic region mainly composed of GABAergic neurons, has been implicated in emotional regulation. Deep brain stimulation of the ZI in humans affects anxiety and depression symptoms, while activation of ZI neurons in mice can either worsen or alleviate anxiety. Currently, there is no direct evidence linking GABAergic neurons in the ZI to depression-like behaviors in rodents.

AIM

To explore the relationship between GABAergic neurons in the ZI and depression-like behaviors in mice.

METHODS

A chronic restraint stress (CRS) model was utilized to induce depression in mice. Whole-cell patch-clamp recordings assessed the excitability changes of GABAergic neurons in the ZI. Additionally, chemogenetic techniques were employed to modulate ZI GABAergic neurons. The performance of the mice in behavioral tests for depression and anxiety was observed.

RESULTS

The findings indicated that GABAergic neurons in the ZI were closely associated with depression-like behaviors in mice. Twenty-eight days after the CRS model was established, depression-like and anxiety-like behaviors were observed in the mice. The excitability of GABAergic neurons in the ZI was reduced. Chemogenetic activation of these neurons alleviated CRS-induced depression-like and anxiety-like behaviors. Conversely, inhibition of GABAergic neurons in the ZI led to changes in emotion-related behavioral outcomes in mice.

CONCLUSION

Activity of GABAergic neurons in the ZI was closely associated with depression-like phenotypes in mice, suggesting that these neurons could be a potential therapeutic target for treating depression.

Current Strategies and Future Directions of Wearable Biosensors for Measuring Stress Biochemical Markers for Neuropsychiatric Applications

Most wearable biosensors aimed at capturing psychological state target stress biomarkers in the form of physical symptoms that can correlate with dysfunction in the central nervous system (CNS). However, such markers lack the specificity needed for diagnostic or preventative applications. Wearable biochemical sensors (WBSs) have the potential to fill this gap, however, the technology is still in its infancy. Most WBSs proposed thus far target cortisol. Although cortisol detection is demonstrated as a viable method for approximating the extent and severity of psychological stress, the hormone also lacks specificity. Multiplex WBSs that simultaneously target cortisol alongside other viable stress-related biochemical markers (SBMs) can prove to be indispensable for understanding how psychological stress contributes to the pathophysiology of neuropsychiatric illnesses (NPIs) and, thus, lead to the discovery of new biomarkers and more objective clinical tools. However, none target more than one SBM implicated in NPIs. Till this review, cortisol's connection to dysfunctions in the CNS, to other SBMs, and their implication in various NPIs has not been discussed in the context of developing WBS technology. As such, this review is meant to inform the biosensing and neuropsychiatric communities of viable future directions and possible challenges for WBS technology for neuropsychiatric applications.

New insights into anti-depression effects of bioactive phytochemicals

Depression is one of the most common psychological disorders, and due to its high prevalence and mortality rates, it imposes a significant disease burden. Contemporary treatments for depression involve various synthetic drugs, which have limitations such as side effects, single targets, and slow onset of action. Unlike synthetic medications, phytochemicals offer the benefits of a multi-target and multi-pathway mode of treatment for depression. In this literature review, we describe the pharmacological actions, experimental models, and clinical trials of the antidepressant effects of various phytochemicals. Additionally, we summarize the potential mechanisms by which these phytochemicals prevent depression, including regulating neurotransmitters and their receptors, the HPA axis, inflammatory responses, managing oxidative stress, neuroplasticity, and the gut microbiome. Phytochemicals exert therapeutic effects through multiple pathways and targets, making traditional Chinese medicine (TCM) a promising adjunctive antidepressant for the prevention, alleviation, and treatment of depression. Therefore, this review aims to provide robust evidence for subsequent research into developing phytochemical resources as effective antidepressant agents.

Neuroimmunometabolism: how metabolism orchestrates immune response in healthy and diseased brain

Neuroimmunometabolism describes how neuroimmune cells, such as microglia, adapt their intracellular metabolic pathways to alter their immune functions in the central nervous system (CNS). Emerging evidence indicates that neurons also orchestrate the microglia-mediated immune response through neuro-immune cross talk, perhaps through metabolic signaling. However, little is known about how the brain's metabolic microenvironment and microglial intracellular metabolism orchestrate the neuroimmune response in healthy and diseased brains. This review addresses the balance of immunometabolic substrates in healthy and diseased brains, their metabolism by brain-resident microglia, and the potential impact of metabolic dysregulation of these substrates on the neuroimmune response and pathophysiology of psychiatric disorders. This review also suggests metabolic reprogramming of microglia as a preventive strategy for the management of neuroinflammation-related brain disorders, including psychiatric diseases.

Prenatal exposure on nanoplastics: A study of spatial transcriptomics in hippocampal offspring

Nanoplastics, as environmental contaminants, are thought to have irreversible impacts on the developing brains of infants and early children; however, the degree of the effects and the mechanisms of damage are unknown. In this study, spatial transcriptomics was used to investigate changes in the hippocampal region of rats descended from maternal exposure to polystyrene nanoplastics (PS-NPs), and the transcriptomes of each spot were sequenced, allowing us to visualize the hippocampus's transcriptional landscape as well as clarify the gene expression profiles of each cell type. Spatial transcriptomics was used to explore changes in the hippocampus region of rats exposed to PS-NPs during brain formation and maturation.The study's findings showed that the offspring hippocampal region had fewer neurons, more astrocytes, and more excitatory neurons 1(ExN1). The pseudo-time study of astrocytes revealed a decrease in C3-type astrocytes and an increase in C2-type astrocytes. This finding raises the possibility that memory impairment in the offspring may result from the developmental obstruction of astrocytes following the intervention of PS-NPs. Moreover, the annotations of four hippocampus regions, CA1, CA2-3, DG, and HILUS, as well as the GO and GSVA of several cell types, revealed deficiencies that can contribute to learning memory impairment. The analysis suggested that decreased neuroglutamate (Glutamate) and γ-aminobutyric acid (GABA) secretion in offspring after PS-NPs intervention was associated with depression. Lastly, intercellular communication revealed alterations in several ligand receptor pathways associated with an increase in astrocytes. In conclusion, spatial transcriptomics reveals that maternal exposure to nanoplastics influences the development of the offspring's hippocampal brain and causes neurotoxicity, which accounts for the offspring's reduction in learning memory function.

Glutamine-glutamate centered metabolism as the potential therapeutic target against Japanese encephalitis virus-induced encephalitis

BACKGROUND

Japanese encephalitis (JE) induced by Japanese encephalitis virus (JEV) infection is the most prevalent diagnosed epidemic viral encephalitis globally. The underlying pathological mechanisms remain largely unknown. Given that viruses are obligate intracellular parasites, cellular metabolic reprogramming triggered by viral infection is intricately related to the establishment of infection and progression of disease. Therefore, uncovering and manipulating the metabolic reprogramming that underlies viral infection will help elucidate the pathogenic mechanisms and develop novel therapeutic strategies.

METHODS

Metabolomics analysis was performed to comprehensively delineate the metabolic profiles in JEV-infected mice brains and neurons. Metabolic flux analysis, quantitative real-time PCR, western blotting and fluorescence immunohistochemistry were utilized to describe detailed glutamine-glutamate metabolic profiles during JEV infection. Exogenous addition of metabolites and associated compounds and RNA interference were employed to manipulate glutamine-glutamate metabolism to clarify its effects on viral replication. The survival rate, severity of neuroinflammation, and levels of viral replication were assessed to determine the efficacy of glutamine supplementation in JEV-challenged mice.

RESULTS

Here, we have delineated a novel perspective on the pathogenesis of JE by identifying an aberrant low flux in glutamine-glutamate metabolism both in vivo and in vitro, which was critical in the establishment of JEV infection and progression of JE. The perturbed glutamine-glutamate metabolism induced neurotransmitter imbalance and created an immune-inhibitory state with increased gamma-aminobutyric acid/glutamate ratio, thus facilitating efficient viral replication both in JEV-infected neurons and the brain of JEV-infected mice. In addition, viral infection restrained the utilization of glutamine via the glutamate-α-ketoglutaric acid axis in neurons, thus avoiding the adverse effects of glutamine oxidation on viral propagation. As the conversion of glutamine to glutamate was inhibited after JEV infection, the metabolism of glutathione (GSH) was simultaneously impaired, exacerbating oxidative stress in JEV-infected neurons and mice brains and promoting the progression of JE. Importantly, the supplementation of glutamine in vivo alleviated the intracranial inflammation and enhanced the survival of JEV-challenged mice.

CONCLUSION

Altogether, our study highlights an aberrant glutamine-glutamate metabolism during JEV infection and unveils how this facilitates viral replication and promotes JE progression. Manipulation of these metabolic alterations may potentially be exploited to develop therapeutic approaches for JEV infection.

Insight into the Structure of the Neutral Amino Acid Transporter B0AT2 Enabled the Discovery of Tiagabine as an Inhibitor

The sodium-dependent membrane transporter SLC6A15 (B0AT2) belongs to the SLC6 family, which comprises carriers of amino acids and monoamines. B0AT2 is expressed in the central nervous system (CNS), including the glutaminergic and GABAergic system. SLC6A15 supplies neurons with neutral amino acids. Its main substrates, branched-chain amino acids, and proline serve for glutamate biosynthesis, whereas silencing of B0AT2 leads to lower levels of neuronal glutamate. Recent research revealed that polymorphisms in the vicinity of slc6a15 are associated with major depressive disorder and anxiety. Mouse B0AT2 knockouts, by contrast, showed an antianxiety feature. Applying computational tools, we constructed models of B0AT2. Their structure was discussed extensively, enabling insight into the determinants of transport mechanism and substrate selectivity. Understanding the molecular basis of the B0AT2 inhibition by loratadine led to the discovery of a new inhibitor that is tiagabine, an anticonvulsant drug prescribed off-label in the treatment of anxiety and possessing antidepressant features. The results showed that tiagabine appears to have a higher affinity to the transporter than loratadine, which is the most potent inhibitor to date. Our findings support the development of new B0AT2 inhibitors that could be useful for investigating their therapeutic relevance, while the identification of tiagabine as a novel SLC6A15 inhibitor adds a new dimension to the pharmacological complexity of this drug.

Impacts of hexafluoropropylene oxide tetrameric acid (HFPO-TeA) on neurodevelopment and GABAergic signaling in zebrafish larvae

Hexafluoropropylene oxide oligomer acids (HFPOs), an emerging environmental pollutant, are increasingly utilized in the manufacture of fluorinated synthetic materials as a substitute for traditional perfluorooctanoic acid (PFOA), resulting in a corresponding rise in detection rates in aquatic environments, which may present inherent safety hazards to ecosystems and public health. However, few data are available on the issue of their toxicity and mechanism. This study aimed to investigate the potential toxic effects of hexafluoroepoxypropane tetrameric acid (HFPO-TeA), a typical HFPO, on the early developmental stages of zebrafish larvae. It revealed that HFPO-TeA exposure resulted in significant detrimental effects, including adverse impacts on general morphological characteristics, such as eye area, heart rate, and swimming bladder, in zebrafish embryos and larvae. Targeted metabolomics and transcriptomics inquiries clarified that HFPO-TeA exposure reduced the levels of the neurotransmitter gamma-aminobutyric acid (GABA) and downregulated the expression of genes related to the GABA pathway. Simultaneously, transgenic zebrafish exhibited that exposure to HFPO-TeA impedes the growth of GABAergic neurons. Moreover, the molecular docking analysis indicated that GABAA receptors might be the potential targets of HFPO-TeA. Taken together, the current data highlights that the HFPO-TeA might not be safe alternatives to PFOA. This study presented a model for HFPO-TeA-induced neurotoxicity in developing zebrafish that can aid in ecological risk assessments.

Fasting the brain for mental health

Unfavorable socioeconomic and geopolitical conditions such as poverty, violence and inequality increase vulnerability to mental disorders. Also, exposure to a poor nutrition such as high-energy dense (HED) diets has been linked to alterations in brain function, leading to anxiety, addiction, and depression. HED diets rich in saturated fatty acids or obesity can activate the innate immune system in the brain, especially microglia, increasing proinflammatory cytokines such as interleukin 1 beta (IL1-β) and interleukin 6 (IL-6), in part, by the stimulation of toll-like receptor 4 (TLR4) and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. Intermittent fasting (IF), an eating protocol characterized by alternating periods of fasting with periods of eating, has gained recognition as a weight-management strategy to reduce obesity. Accordingly, during IF inflammation and brain function can be modulated by production of ketone bodies and modulation of the intestinal microbiota, which also promote the induction of brain-derived neurotrophic factor (BDNF), which is involved in neurogenesis and neuronal plasticity. Although IF has contributed to reduce body weight and improve metabolic profiles, its influence on mental health remains an evolving field of research. Here, we provide experimental evidence supporting the role of IF reducing neuroinflammation as a valuable approach to improve mental health.

SARS-CoV-2 variants mediated tissue-specific metabolic reprogramming determines the disease pathophysiology in a hamster model

Despite significant effort, a clear understanding of host tissue-specific responses and their implications for immunopathogenicity against the severe acute respiratory syndrome coronavirus2 (SARS-CoV-2) variant infection has remained poorly defined. To shed light on the interaction between tissues and SARS-CoV-2 variants, we sought to characterize the complex relationship among acute multisystem manifestations, dysbiosis of the gut microbiota, and the resulting implications for SARS-CoV-2 variant-specific immunopathogenesis in the Golden Syrian Hamster (GSH) model using multi-omics approaches. Our investigation revealed the presence of increased SARS-CoV-2 genomic RNA in diverse tissues of delta-infected GSH compared to the omicron variant. Multi-omics analyses uncovered distinctive metabolic responses between the delta and omicron variants, with the former demonstrating dysregulation in synaptic transmission proteins associated with neurocognitive disorders. Additionally, delta-infected GSH exhibited an altered fecal microbiota composition, marked by increased inflammation-associated taxa and reduced commensal bacteria compared to the omicron variant. These findings underscore the SARS-CoV-2-mediated tissue insult, characterized by modified host metabolites, neurological protein dysregulation, and gut dysbiosis, highlighting the compromised gut-lung-brain axis during acute infection.

Exploring the Effects of Prefrontal Transcranial Direct Current Stimulation on Brain Metabolites: A Concurrent tDCS-MRS Study

Transcranial Direct Current Stimulation (tDCS) is a non-invasive brain stimulation technique used to modulates cortical brain activity. However, its effects on brain metabolites within the dorsolateral prefrontal cortex (DLPFC), a crucial area targeted for brain stimulation in mental disorders, remain unclear. This study aimed to investigate whether prefrontal tDCS over the left and right DLPFC modulates levels of key metabolites, including gamma-aminobutyric acid (GABA), glutamate (Glu), glutamine/glutamate (Glx), N-acetylaspartate (NAA), near to the target region and to explore potential sex-specific effects on these metabolite concentrations. A total of 41 healthy individuals (19 female, M_age = 25 years, SD = 3.15) underwent either bifrontal active (2 mA for 20 min) or sham tDCS targeting the left (anode: F3) and right (cathode: F4) DLPFC within a 3 Tesla MRI scanner. Magnetic resonance spectroscopy (MRS) was used to monitor neurometabolic changes before, during, and after 40 min of tDCS, with measurements of two 10-min intervals during stimulation. A single voxel beneath F3 was used for metabolic quantification. Results showed a statistically significant increase in Glx levels under active tDCS compared to the sham condition, particularly during the second 10-min window and persisting into the post-stimulation phase. No significant changes were observed in other metabolites, but consistent sex differences were detected. Specifically, females showed lower levels of NAA and GABA under active tDCS compared to the sham condition, while no significant changes were observed in males. E-field modeling showed no significant differences in field magnitudes between sexes, and the magnitude of the e-fields did not correlate with changes in Glx levels between active and sham stimulation during the second interval or post-stimulation. This study demonstrates that a single session of prefrontal tDCS significantly elevates Glx levels in the left DLPFC, with effects persisting post-stimulation. However, the observed sex differences in the neurochemical response to tDCS were not linked to specific stimulation intervals or variations in e-field magnitudes, highlighting the complexity of tDCS effects and the need for personalized neuromodulation strategies.

GABA in early brain development: A dual role review

This comprehensive review examines the multifaceted roles of gamma-aminobutyric acid (GABA) in early brain development. GABA, traditionally recognized for its inhibitory functions in the mature brain, also exhibits excitatory effects during early neural development. This article explores the mechanisms behind GABA's dual roles, detailing its impact on the properties of the immature brain, the mechanisms of GABA-mediated excitation, the role of GABA-mediated presynaptic inhibition, the trophic actions of GABA during early development, GABA regulation of neurite growth and GABA-mediated cell differentiation in the immature brain. Emphasizing recent research findings, the review highlights the significance of GABAergic signalling in shaping the developing brain and its potential implications for understanding neurodevelopmental disorders.

Reverse phase protein array-based investigation of mitochondrial genes reveals alteration of glutaminolysis in the parahippocampal cortex of people who died by suicide

A moderating hub between resting state networks (RSNs) and the medial temporal lobe (MTL) is the parahippocampal cortex (PHC). Abnormal activity has been reported in depressed patients and suicide attempters in this region. Alterations in neuronal mitochondrial function may contribute to depression and suicidal behavior. However, little is known about the underlying molecular level changes in relevant structures. Specifically, expressional changes related to suicide have not been reported in the PHC. In this study, we compared the protein expression levels of genes encoding tricarboxylic acid (TCA) cycle enzymes in the PHC of adult individuals who died by suicide by reverse phase protein array (RPPA), which was corroborated by qRT-PCR at the mRNA level. Postmortem human brain samples were collected from 12 control and 10 suicidal individuals. The entorhinal cortex, which is topographically anterior to the PHC in the parahippocampal gyrus, and some other cortical brain regions were utilized for comparison. The results of the RPPA analysis revealed that the protein levels of DLD, OGDH, SDHB, SUCLA2, and SUCLG2 subunits were significantly elevated in the PHC but not in other cortical brain regions. In accordance with these findings, the mRNA levels of the respective subunits were also increased in the PHC. The subunits with altered levels are implicated in enzyme complexes involved in the oxidative decarboxylation branch of glutamine catabolism. These data suggest a potential role of glutaminolysis in the pathophysiology of suicidal behavior in the PHC.

Prefrontal cortical circuits in social behaviors: an overview

Social behaviors are fundamental and intricate functions in both humans and animals, governed by the interplay of social cognition and emotions. A noteworthy feature of several neuropsychiatric disorders, including autism spectrum disorder (ASD) and schizophrenia (SCZ), is a pronounced deficit in social functioning. Despite a burgeoning body of research on social behaviors, the precise neural circuit mechanisms underpinning these phenomena remain to be elucidated. In this paper, we review the pivotal role of the prefrontal cortex (PFC) in modulating social behaviors, as well as its functional alteration in social disorders in ASD or SCZ. We posit that PFC dysfunction may represent a critical hub in the pathogenesis of psychiatric disorders characterized by shared social deficits. Furthermore, we delve into the intricate connectivity of the medial PFC (mPFC) with other cortical areas and subcortical brain regions in rodents, which exerts a profound influence on social behaviors. Notably, a substantial body of evidence underscores the role of N-methyl-D-aspartate receptors (NMDARs) and the proper functioning of parvalbumin-positive interneurons within the mPFC for social regulation. Our overarching goal is to furnish a comprehensive understanding of these intricate circuits and thereby contribute to the enhancement of both research endeavors and clinical practices concerning social behavior deficits.

Ketamine and chronic treatment-resistant depression: real-world practice and after relapse

BACKGROUND

Chronic treatment-resistant depression (TRD) poses a major challenge for clinicians. Ketamine has shown a rapid but short-lived antidepressant effect in several studies involving TRD patients with different demographic and clinical profiles. Our study aimed to assess the antidepressant effect of serial infusion sessions of ketamine in patients with chronic TRD and evaluate the severity of symptoms after relapse and the general psychiatric health of the responding patients.

METHODS

In this single arm open-label study, six infusions of ketamine at 0.5 mg/kg were administered to chronic TRD patients for approximately two weeks. Response and remission rates, side effects, adverse events and after-relapse symptoms were evaluated, and patients were followed for three months.

RESULTS

23 patients underwent at least one infusion session, and 18 patients completed the six sessions. Twelve (66.67%) patients responded to the treatment at some point, and 11 (61.11%) patients maintained response after the end of the treatment protocol. One infusion was not sufficient to achieve a response (P > 0.9999, z = 1.81), and more than half of the responders met the response criteria after the third infusion. Only one patient (5.56%) achieved remission at the end of the infusion phase. All but one ketamine responders relapsed within one month after the end of the treatment. There was no statistical difference between baseline and after-relapse MADRS scores (P = 0.7886, 95% CI=-5.512-4.312, R2 = 0,008411). However, a high incidence of serious adverse events related to suicidality was evident; one of the non-responding patients attempted suicide and several attempts to sedate this patient with benzodiazepines failed. Two responding patients ended up with a suicidal attempt or severe suicidal thoughts.

CONCLUSIONS

Introducing rapid-acting antidepressant to manage TRD patients in clinical practice demands further investigation, and the benefit-to-harm ratio should be assessed in the light of the increased risk of suicidality.

Treatment-resistant depression: molecular mechanisms and management

Due to the heterogeneous nature of depression, the underlying etiological mechanisms greatly differ among individuals, and there are no known subtype-specific biomarkers to serve as precise targets for therapeutic efficacy. The extensive research efforts over the past decades have not yielded much success, and the currently used first-line conventional antidepressants are still ineffective for close to 66% of patients. Most clinicians use trial-and-error treatment approaches, which seem beneficial to only a fraction of patients, with some eventually developing treatment resistance. Here, we review evidence from both preclinical and clinical studies on the pathogenesis of depression and antidepressant treatment response. We also discuss the efficacy of the currently used pharmacological and non-pharmacological approaches, as well as the novel emerging therapies. The review reveals that the underlying mechanisms in the pathogenesis of depression and antidepressant response, are not specific, but rather involve an interplay between various neurotransmitter systems, inflammatory mediators, stress, HPA axis dysregulation, genetics, and other psycho-neurophysiological factors. None of the current depression hypotheses sufficiently accounts for the interactional mechanisms involved in both its etiology and treatment response, which could partly explain the limited success in discovering efficacious antidepressant treatment. Effective management of treatment-resistant depression (TRD) requires targeting several interactional mechanisms, using subtype-specific and/or personalized therapeutic modalities, which could, for example, include multi-target pharmacotherapies in augmentation with psychotherapy and/or other non-pharmacological approaches. Future research guided by interaction mechanisms hypotheses could provide more insights into potential etiologies of TRD, precision biomarker targets, and efficacious therapeutic modalities.

Ketogenic diets in clinical psychology: examining the evidence and implications for practice

Introduction

The application of ketogenic dietary interventions to mental health treatments is increasingly acknowledged within medical and psychiatric fields, yet its exploration in clinical psychology remains limited. This article discusses the potential implications of ketogenic diets, traditionally utilized for neurological disorders, within broader mental health practices.

Methods

This article presents a perspective based on existing ketogenic diet research on historical use, biological mechanisms, and therapeutic benefits. It examines the potential application of these diets in mental health treatment and their relevance to clinical psychology research and practice.

Results

The review informs psychologists of the therapeutic benefits of ketogenic diets and introduces to the psychology literature the underlying biological mechanisms involved, such as modulation of neurotransmitters, reduction of inflammation, and stabilization of brain energy metabolism, demonstrating their potential relevance to biopsychosocial practice in clinical psychology.

Conclusion

By considering metabolic therapies, clinical psychologists can broaden their scope of biopsychosocial clinical psychology practice. This integration provides a care model that incorporates knowledge of the ketogenic diet as a treatment option in psychiatric care. The article emphasizes the need for further research and training for clinical psychologists to support the effective implementation of this metabolic psychiatry intervention.

Pathogenesis and therapeutic strategies for cancer-related depression

Depression is a common co-morbidity among cancer cases, which has a detrimental influence on cancer treatment and prognosis. Recent advancements in the neurobiology of depression and cancer pathophysiology have revealed several shared biobehavioral mechanisms and introduced new therapeutic strategies. In this review, we summarize the biological mechanisms driving cancer-related depression, including psychosocial factors, immuno-inflammatory processes, chronic stress, dysbiosis of gut microbiota, and medically-induced factors. Interventions used for cancer-related depression may include psychosocial therapies, pharmacological therapies, immunotherapies, psychobiological medications, and dietary strategies. This review could inspire the elucidation of possible co-occurring mechanisms and complex interactions between cancer and depression, provide an opportunity to propose faster and more effective therapies for cancer-related depression, and well as new strategies for cancer in the future.

Resting-State EEG Alterations of Practice-Related Spectral Activity and Connectivity Patterns in Depression

BACKGROUND

Depression presents with altered energy regulation and neural plasticity. Previous electroencephalography (EEG) studies showed that practice in learning tasks increases power in beta range (13-30 Hz) in healthy subjects but not in those with impaired plasticity. Here, we ascertain whether depression presents with alterations of spectral activity and connectivity before and after a learning task.

METHODS

We used publicly available resting-state EEG recordings (64 electrodes) from 122 subjects. Based on Beck Depression Inventory (BDI) scores, they were assigned to either a high BDI (hBDI, BDI > 13, N = 46) or a control (CTL, BDI < 7, N = 75) group. We analyzed spectral activity, theta-beta, and theta-gamma phase-amplitude coupling (PAC) of EEG recorded at rest before and after a learning task.

RESULTS

At baseline, compared to CTL, hBDI exhibited greater power in beta over fronto-parietal regions and in gamma over the right parieto-occipital area. At post task, power increased in all frequency ranges only in CTL. Theta-beta and theta-gamma PAC were greater in hBDI at baseline but not after the task.

CONCLUSIONS

The lack of substantial post-task growth of beta power in depressed subjects likely represents power saturation due to greater baseline values. We speculate that inhibitory/excitatory imbalance, altered plasticity mechanisms, and energy dysregulation present in depression may contribute to this phenomenon.

Factors Associated with the Development of Depression and the Influence of Obesity on Depressive Disorders: A Narrative Review

Depression affects several aspects of life, including socioeconomic status, relationships, behavior, emotions, and overall health. The etiology of depression is complex and influenced by various factors, with obesity emerging as a significant contributor. This narrative review aims to investigate the factors associated with the development of depression, with a particular focus on the role of obesity. The literature search was conducted on PubMed, Embase, and PsycINFO from May to July 2024. The review highlights the impact of environmental and socioeconomic conditions; lifestyle choices, including physical activity and dietary habits; stress; traumatic experiences; neurotransmitter imbalances; medical and psychological conditions; hormone fluctuations; and epigenetic factors on depression. A key emphasis is placed on the inflammatory processes linked to obesity, which may drive the bidirectional relationship between obesity and depression. The findings suggest that obesity is associated with an increased risk of depression, potentially due to chronic inflammation, neurochemical dysregulation, and the emotional and social challenges related to weight stigma and obesity management. Understanding these interconnected factors is important for developing targeted interventions to address both obesity and depression, leading to improved quality of life for those affected.

Cadmium neurotoxicity: Insights into behavioral effect and neurodegenerative diseases

Cadmium (Cd) induced neurotoxicity has become a growing concern due to its potential adverse effects on the Central Nervous System. Cd is a Heavy Metal (HM) that is released into the environment, through several industrial processes. It poses a risk to the health of the community by polluting air, water, and soil. Cd builds up in the brain and other neural tissues, raising concerns about its effect on the nervous system due to its prolonged biological half-life. Cd can enter into the neurons, hence increasing the production of Reactive Oxygen Species (ROS) in them and impairing their antioxidant defenses. Cd disrupts the Calcium (Ca2+) balance in neurons, affects the function of the mitochondria, and triggers cell death pathways. As a result of these pathways, the path to the development of many neurological diseases affected by environmental factors, especially Cd, such as Alzheimer's Disease (AD) and Amyotrophic Lateral Sclerosis (ALS) is facilitated. There are cognitive deficits associated with long exposure to Cd. Memory disorders are present in both animals and humans. Cd alters the brain's function and performance in critical periods. There are lifelong consequences of Cd exposure during critical brain development stages. The susceptibility to neurotoxic effects is increased by interactions with a variety of risk factors. Cd poses risks to neuronal function and behavior, potentially contributing to neurodegenerative diseases like Parkinson's disease (PD) and AD as well as cognitive issues. This article offers a comprehensive overview of Cd-induced neurotoxicity, encompassing risk assessment, adverse effect levels, and illuminating intricate pathways.

Elucidating genetic and molecular basis of altered higher-order brain structure-function coupling in major depressive disorder

Previous studies have shown that major depressive disorder (MDD) patients exhibit structural and functional impairments, but few studies have investigated changes in higher-order coupling between structure and function. Here, we systematically investigated the effect of MDD on higher-order coupling between structural connectivity (SC) and functional connectivity (FC). Each brain region was mapped into embedding vector by the node2vec algorithm. We used support vector machine (SVM) with the brain region embedding vector to distinguish MDD patients from health controls (HCs) and identify the most discriminative brain regions. Our study revealed that MDD patients had decreased higher-order coupling in connections between the most discriminative brain regions and local connections in rich-club organization and increased higher-order coupling in connections between the ventral attentional network and limbic network compared with HCs. Interestingly, transcriptome-neuroimaging association analysis demonstrated the correlations between regional rSC-FC coupling variations between MDD patients and HCs and α/β-hydrolase domain-containing 6 (ABHD6), β 1,3-N-acetylglucosaminyltransferase-9(β3GNT9), transmembrane protein 45B (TMEM45B), the correlation between regional dSC-FC coupling variations and retinoic acid early transcript 1E antisense RNA 1(RAET1E-AS1), and the correlations between regional iSC-FC coupling variations and ABHD6, β3GNT9, katanin-like 2 protein (KATNAL2). In addition, correlation analysis with neurotransmitter receptor/transporter maps found that the rSC-FC and iSC-FC coupling variations were both correlated with neuroendocrine transporter (NET) expression, and the dSC-FC coupling variations were correlated with metabotropic glutamate receptor 5 (mGluR5). Further mediation analysis explored the relationship between genes, neurotransmitter receptor/transporter and MDD related higher-order coupling variations. These findings indicate that specific genetic and molecular factors underpin the observed disparities in higher-order SC-FC coupling between MDD patients and HCs. Our study confirmed that higher-order coupling between SC and FC plays an important role in diagnosing MDD. The identification of new biological evidence for MDD etiology holds promise for the development of innovative antidepressant therapies.

Embryonic Zebrafish as a Model for Investigating the Interaction between Environmental Pollutants and Neurodegenerative Disorders

Environmental pollutants have been linked to neurotoxicity and are proposed to contribute to neurodegenerative disorders. The zebrafish model provides a high-throughput platform for large-scale chemical screening and toxicity assessment and is widely accepted as an important animal model for the investigation of neurodegenerative disorders. Although recent studies explore the roles of environmental pollutants in neurodegenerative disorders in zebrafish models, current knowledge of the mechanisms of environmentally induced neurodegenerative disorders is relatively complex and overlapping. This review primarily discusses utilizing embryonic zebrafish as the model to investigate environmental pollutants-related neurodegenerative disease. We also review current applicable approaches and important biomarkers to unravel the underlying mechanism of environmentally related neurodegenerative disorders. We found embryonic zebrafish to be a powerful tool that provides a platform for evaluating neurotoxicity triggered by environmentally relevant concentrations of neurotoxic compounds. Additionally, using variable approaches to assess neurotoxicity in the embryonic zebrafish allows researchers to have insights into the complex interaction between environmental pollutants and neurodegenerative disorders and, ultimately, an understanding of the underlying mechanisms related to environmental toxicants.

Glutamate-Mediated Excitotoxicity in the Pathogenesis and Treatment of Neurodevelopmental and Adult Mental Disorders

Glutamate is the main excitatory neurotransmitter in the brain wherein it controls cognitive functional domains and mood. Indeed, brain areas involved in memory formation and consolidation as well as in fear and emotional processing, such as the hippocampus, prefrontal cortex, and amygdala, are predominantly glutamatergic. To ensure the physiological activity of the brain, glutamatergic transmission is finely tuned at synaptic sites. Disruption of the mechanisms responsible for glutamate homeostasis may result in the accumulation of excessive glutamate levels, which in turn leads to increased calcium levels, mitochondrial abnormalities, oxidative stress, and eventually cell atrophy and death. This condition is known as glutamate-induced excitotoxicity and is considered as a pathogenic mechanism in several diseases of the central nervous system, including neurodevelopmental, substance abuse, and psychiatric disorders. On the other hand, these disorders share neuroplasticity impairments in glutamatergic brain areas, which are accompanied by structural remodeling of glutamatergic neurons. In the current narrative review, we will summarize the role of glutamate-induced excitotoxicity in both the pathophysiology and therapeutic interventions of neurodevelopmental and adult mental diseases with a focus on autism spectrum disorders, substance abuse, and psychiatric disorders. Indeed, glutamatergic drugs are under preclinical and clinical development for the treatment of different mental diseases that share glutamatergic neuroplasticity dysfunctions. Although clinical evidence is still limited and more studies are required, the regulation of glutamate homeostasis is attracting attention as a potential crucial target for the control of brain diseases.

B cells and the stressed brain: emerging evidence of neuroimmune interactions in the context of psychosocial stress and major depression

The immune system has emerged as a key regulator of central nervous system (CNS) function in health and in disease. Importantly, improved understanding of immune contributions to mood disorders has provided novel opportunities for the treatment of debilitating stress-related mental health conditions such as major depressive disorder (MDD). Yet, the impact to, and involvement of, B lymphocytes in the response to stress is not well-understood, leaving a fundamental gap in our knowledge underlying the immune theory of depression. Several emerging clinical and preclinical findings highlight pronounced consequences for B cells in stress and MDD and may indicate key roles for B cells in modulating mood. This review will describe the clinical and foundational observations implicating B cell-psychological stress interactions, discuss potential mechanisms by which B cells may impact brain function in the context of stress and mood disorders, describe research tools that support the investigation of their neurobiological impacts, and highlight remaining research questions. The goal here is for this discussion to illuminate both the scope and limitations of our current understanding regarding the role of B cells, stress, mood, and depression.

A Bright Future? A Perspective on Class C GPCR Based Genetically Encoded Biosensors

One of the major challenges in molecular neuroscience today is to accurately monitor neurotransmitters, neuromodulators, peptides, and various other biomolecules in the brain with high temporal and spatial resolution. Only a comprehensive understanding of neuromodulator dynamics, their release probability, and spatial distribution will unravel their ultimate role in cognition and behavior. This Perspective offers an overview of potential design strategies for class C GPCR-based biosensors. It briefly highlights current applications of GPCR-based biosensors, with a primary focus on class C GPCRs and their unique structural characteristics compared with other GPCR subfamilies. The discussion offers insights into plausible future design approaches for biosensor development targeting members of this specific GPCR subfamily. It is important to note that, at this stage, we are contemplating possibilities rather than presenting a concrete guide, as the pipeline is still under development.

Non-Targeted Metabolomics Investigation of a Sub-Chronic Variable Stress Model Unveils Sex-Dependent Metabolic Differences Induced by Stress

Depression is twice as prevalent in women as in men, however, most preclinical studies of depression have used male rodent models. This study aimed to examine how stress affects metabolic profiles depending on sex using a rodent depression model: sub-chronic variable stress (SCVS). The SCVS model of male and female mice was established in discovery and validation sets. The stress-induced behavioral phenotypic changes were similar in both sexes, however, the metabolic profiles of female plasma and brain became substantially different after stress, whereas those of males did not. Four stress-differential plasma metabolites-β-hydroxybutyric acid (BHB), L-serine, glycerol, and myo-inositol-could yield biomarker panels with excellent performance to discern the stressed individuals only for females. Disturbances in BHB, glucose, 1,5-anhydrosorbitol, lactic acid, and several fatty acids in the plasma of stressed females implied a systemic metabolic shift to β-oxidation in females. The plasma levels of BHB and corticosterone only in stressed females were observed not only in SCVS but also in an acute stress model. These results collectively suggest a sex difference in the metabolic responses by stress, possibly involving the energy metabolism shift to β-oxidation and the HPA axis dysregulation in females.

Structural and biochemical alterations in dendritic spines as key mechanisms for severe mental illnesses

Severe mental illnesses (SMI) collectively affect approximately 20% of the global population, as estimated by the World Health Organization (WHO). Despite having diverse etiologies, clinical symptoms, and pharmacotherapies, these diseases share a common pathophysiological characteristic: the misconnection of brain areas involved in reality perception, executive control, and cognition, including the corticolimbic system. Dendritic spines play a crucial role in excitatory neurotransmission within the central nervous system. These small structures exhibit remarkable plasticity, regulated by factors such as neurotransmitter tone, neurotrophic factors, and innate immunity-related molecules, and other mechanisms - all of which are associated with the pathophysiology of SMI. However, studying dendritic spine mechanisms in both healthy and pathological conditions in patients is fraught with technical limitations. This is where animal models related to these diseases become indispensable. They have played a pivotal role in elucidating the significance of dendritic spines in SMI. In this review, the information regarding the potential role of dendritic spines in SMI was summarized, drawing from clinical and animal model reports. Also, the implications of targeting dendritic spine-related molecules for SMI treatment were explored. Specifically, our focus is on major depressive disorder and the neurodevelopmental disorders schizophrenia and autism spectrum disorder. Abundant clinical and basic research has studied the functional and structural plasticity of dendritic spines in these diseases, along with potential pharmacological targets that modulate the dynamics of these structures. These targets may be associated with the clinical efficacy of the pharmacotherapy.

Childhood Apraxia of Speech: Exploring Gluten Sensitivity and Changes in Glutamate and Gamma-Aminobutyric Acid Plasma Levels

BACKGROUND

Individuals with childhood apraxia of speech (CAS) were reported to have genetic variations related to gluten sensitivity and some neuroanatomic changes, which could be associated with alterations in neurotransmitters levels such as glutamate and gamma-aminobutyric acid (GABA). The aim was to measure the levels of antigliadin immunoglobulin A (IgA) antibody, glutamate, and GABA in the plasma of children with CAS compared with children with delayed language development (DLD) and neurotypical (NT) children.

METHODS

The participants (N = 120) were in three groups: Group I for CAS (N = 30), Group II for DLD (N = 60), and Group III for NT (N = 30). The abilities of children in Groups I and II were evaluated. The plasma levels of antigliadin IgA, glutamate, and GABA were determined by enzyme-linked immunosorbent assay.

RESULTS

The intelligence quotient and expressive language age in Group I were low compared with Group II (P = 0.001; 0.004). The levels of antigliadin IgA and glutamate in Group I were higher compared with the other two groups, whereas the level of GABA was lower (P < 0.0001). An imbalance between glutamate and GABA was found in Group I. In Group II, no measures differed from NTs except lower GABA levels (P = 0.0007).

CONCLUSIONS

The elevated levels of antigliadin IgA antibody and glutamate demonstrated high sensitivity and specificity, differentiating children with CAS from children with DLD and NT children. The low levels of GABA contributed to the imbalance between the excitatory and inhibitory neurotransmitters' levels detected in children with CAS.

Efficacy and safety of ketamine and esketamine for unipolar and bipolar depression: an overview of systematic reviews with meta-analysis

BACKGROUND

Unipolar and bipolar depression present treatment challenges, with patients sometimes showing limited or no response to standard medications. Ketamine and its enantiomer, esketamine, offer promising alternative treatments that can quickly relieve suicidal thoughts. This Overview of Reviews (OoR) analyzed and synthesized systematic reviews (SRs) with meta-analysis on randomized clinical trials (RCTs) involving ketamine in various formulations (intravenous, intramuscular, intranasal, subcutaneous) for patients with unipolar or bipolar depression. We evaluated the efficacy and safety of ketamine and esketamine in treating major depressive episodes across various forms, including unipolar, bipolar, treatment-resistant, and non-resistant depression, in patient populations with and without suicidal ideation, aiming to comprehensively assess their therapeutic potential and safety profile.

METHODS

Following PRIOR guidelines, this OoR's protocol was registered on Implasy (ID:202150049). Searches in PubMed, Scopus, Cochrane Library, and Epistemonikos focused on English-language meta-analyses of RCTs of ketamine or esketamine, as monotherapy or add-on, evaluating outcomes like suicide risk, depressive symptoms, relapse, response rates, and side effects. We included studies involving both suicidal and non-suicidal patients; all routes and formulations of administration (intravenous, intramuscular, intranasal) were considered, as well as all available comparisons with control interventions. We excluded meta-analysis in which the intervention was used as anesthesia for electroconvulsive therapy or with a randomized ascending dose design. The selection, data extraction, and quality assessment of studies were carried out by pairs of reviewers in a blinded manner. Data on efficacy, acceptability, and tolerability were extracted.

RESULTS

Our analysis included 26 SRs and 44 RCTs, with 3,316 subjects. The intervention is effective and well-tolerated, although the quality of the included SRs and original studies is poor, resulting in low certainty of evidence.

LIMITATIONS

This study is limited by poor-quality SRs and original studies, resulting in low certainty of the evidence. Additionally, insufficient available data prevents differentiation between the effects of ketamine and esketamine in unipolar and bipolar depression.

CONCLUSION

While ketamine and esketamine show promising therapeutic potential, the current evidence suffers from low study quality. Enhanced methodological rigor in future research will allow for a more informed application of these interventions within the treatment guidelines for unipolar and bipolar depression.

SYSTEMATIC REVIEW REGISTRATION

[https://inplasy.com/inplasy-2021-5-0049/], identifier (INPLASY202150049).

Alterations of the glutamatergic system in diabetes mellitus

Diabetes mellitus (DM) is a chronic disease characterized by elevated blood glucose levels caused by a lack of insulin production (type 1 diabetes) or insulin resistance (type 2 diabetes). It is well known that DM is associated with cognitive deficits and metabolic and neurophysiological changes in the brain. Glutamate is the main excitatory neurotransmitter in the central nervous system that plays a key role in synaptic plasticity, learning, and memory processes. An increasing number of studies have suggested that abnormal activity of the glutamatergic system is implicated in the pathophysiology of DM. Dysfunction of glutamatergic neurotransmission in the central nervous system can provide an important neurobiological substrate for many disorders. Magnetic resonance spectroscopy (MRS) is a non-invasive technique that allows a better understanding of the central nervous system factors by measuring in vivo the concentrations of brain metabolites within the area of interest. Here, we briefly review the MRS studies that have examined glutamate levels in the brain of patients with DM. The present article also summarizes the available data on abnormalities in glutamatergic neurotransmission observed in different animal models of DM. In addition, the role of gut microbiota in the development of glutamatergic alterations in DM is addressed. We speculate that therapeutic strategies targeting the glutamatergic system may be beneficial in the treatment of central nervous system-related changes in diabetic patients.

The Role of Glutamine Homeostasis in Emotional and Cognitive Functions

Glutamine (Gln), a non-essential amino acid, is synthesized de novo by glutamine synthetase (GS) in various organs. In the brain, GS is exclusively expressed in astrocytes under normal physiological conditions, producing Gln that takes part in glutamatergic neurotransmission through the glutamate (Glu)-Gln cycle. Because the Glu-Gln cycle and glutamatergic neurotransmission play a pivotal role in normal brain activity, maintaining Gln homeostasis in the brain is crucial. Recent findings indicated that a neuronal Gln deficiency in the medial prefrontal cortex in rodents led to depressive behaviors and mild cognitive impairment along with lower glutamatergic neurotransmission. In addition, exogenous Gln supplementation has been tested for its ability to overcome neuronal Gln deficiency and reverse abnormal behaviors induced by chronic immobilization stress (CIS). Although evidence is accumulating as to how Gln supplementation contributes to normalizing glutamatergic neurotransmission and the Glu-Gln cycle, there are few reviews on this. In this review, we summarize recent evidence demonstrating that Gln supplementation ameliorates CIS-induced deleterious changes, including an imbalance of the Glu-Gln cycle, suggesting that Gln homeostasis is important for emotional and cognitive functions. This is the first review of detailed mechanistic studies on the effects of Gln supplementation on emotional and cognitive functions.

Depression and the Glutamate/GABA-Glutamine Cycle

Many features of major depressive disorder are mirrored in rodent models of psychological stress. These models have been used to examine the relationship between the activation of the hypothalamic- pituitary axis in response to stress, the development of oxidative stress and neuroinflammation, the dominance of cholinergic neurotransmission and the associated increase in REM sleep pressure. Rodent models have also provided valuable insights into the impairment of glycolysis and brain glucose utilization by the brain under stress, the resulting decrease in brain energy production and the reduction in glutamate/GABA-glutamine cycling. The rapidly acting antidepressants, scopolamine, ketamine and ECT, all raise extracellular glutamate and scopolamine and ketamine have specifically been shown to increase glutamate/GABA-glutamine cycling in men and rodents with corresponding short-term relief of depression. The nightly use of gammahydroxybutyrate (GHB) may achieve more permanent results and may even act prophylactically to prevent the development or recurrence of depression. GHB is a GABAB agonist and restores the normal balance between cholinergic and monoaminergic neurotransmission by inhibiting cholinergic neurotransmission. It relieves REM sleep pressure. GHB's metabolism generates NADPH, a key antioxidant cofactor. Its metabolism also generates succinate, the tricarboxylic acid cycle intermediate, to provide energy to the cell and to synthesize glutamate. In both animals and man, GHB increases the level of brain glutamate.

Efficacy and safety of zuranolone co-initiated with an antidepressant in adults with major depressive disorder: results from the phase 3 CORAL study

Major depressive disorder (MDD) is a mental health disorder that can cause disability and functional impairment that standard-of-care (SOC) antidepressant therapies (ADTs) can take weeks to treat. Zuranolone is a neuroactive steroid and positive allosteric modulator of synaptic and extrasynaptic γ-aminobutyric acid (GABA) type A receptors approved as an oral, once-daily, 14-day treatment course in adults with postpartum depression and under investigation in adults with MDD. The phase 3 CORAL Study (NCT04476030) evaluated the efficacy and safety of zuranolone 50 mg co-initiated with SOC ADT (zuranolone+ADT) vs placebo co-initiated with SOC ADT (placebo+ADT) in adults with MDD. Patients were randomized 1:1 to once-daily, blinded zuranolone+ADT or placebo+ADT for 14 days, then continued open-label SOC ADT for 28 more days. The primary endpoint was change from baseline (CFB) in the 17-item Hamilton Rating Scale for Depression (HAMD-17) total score at Day 3. Among 425 patients in the full analysis set, CFB in HAMD-17 total score at Day 3 was significantly improved with zuranolone+ADT vs placebo+ADT (least squares mean [standard error], -8.9 [0.39] vs -7.0 [0.38]; p = 0.0004). The majority of patients receiving zuranolone+ADT that experienced treatment-emergent adverse events (TEAEs) reported mild or moderate events. The most common TEAEs present in ≥10% of patients in either zuranolone+ADT or placebo+ADT groups were somnolence, dizziness, headache, and nausea. These results demonstrate that zuranolone+ADT provided more rapid improvement in depressive symptoms compared with placebo+ADT in patients with MDD, with a safety profile consistent with previous studies. Clinical trial registration: ClinicalTrials.gov identifier: NCT04476030.

Gut feelings: the relations between depression, anxiety, psychotropic drugs and the gut microbiome

The gut microbiome is involved in the bi-directional relationship of the gut - brain axis. As most studies of this relationship are small and do not account for use of psychotropic drugs (PTDs), we explored the relations of the gut microbiome with several internalizing disorders, while adjusting for PTDs and other relevant medications, in 7,656 Lifelines participants from the Northern Netherlands (5,522 controls and 491 participants with at least one internalizing disorder). Disorders included dysthymia, major depressive disorder (MDD), any depressive disorder (AnyDep: dysthymia or MDD), generalized anxiety disorder (GAD) and any anxiety disorder (AnyAnx: GAD, social phobia and panic disorder). Compared to controls, 17 species were associated with depressive disorders and 3 were associated with anxiety disorders. Around 90% of these associations remained significant (FDR <0.05) after adjustment for PTD use, suggesting that the disorders, not PTD use, drove these associations. Negative associations were observed for the butyrate-producing bacteria Ruminococcus bromii in participants with AnyDep and for Bifidobacterium bifidum in AnyAnx participants, along with many others. Tryptophan and glutamate synthesis modules and the 3,4-Dihydroxyphenylacetic acid synthesis module (related to dopamine metabolism) were negatively associated with MDD and/or dysthymia. After additional adjustment for functional gastrointestinal disorders and irritable bowel syndrome, these relations remained either statistically (FDR <0.05) or nominally (P < 0.05) significant. Overall, multiple bacterial species and functional modules were associated with internalizing disorders, including gut - brain relevant components, while associations to PTD use were moderate. These findings suggest that internalizing disorders rather than PTDs are associated with gut microbiome differences relative to controls.

NMR metabolomics study of chronic low-dose exposure to a cocktail of persistent organic pollutants

Nowadays, exposure to endocrine-disrupting chemicals (EDCs), including persistent organic pollutants (POPs), is one of the most critical threats to public health. EDCs are chemicals that mimic, block, or interfere with hormones in the body's endocrine system and have been associated with a wide range of health issues. This innovative, untargeted metabolomics study investigates chronic low-dose internal exposure to a cocktail of POPs on multiple tissues that are known to accumulate these lipophilic compounds. Interestingly, the metabolic response differs among selected tissues/organs in mice. In the liver, we observed a dynamic effect according to the exposure time and the doses of POPs. In the brain tissue, the situation is the opposite, leading to the conclusion that the presence of POPs immediately gives a saturated effect that is independent of the dose and the duration of exposure studied. By contrast, for the adipose tissues, nearly no effect is observed. This metabolic profiling leads to a holistic and dynamic overview of the main metabolic pathways impacted in lipophilic tissues by a cocktail of POPs.

The Cerebellum's Role in Affective Disorders: The Onset of Its Social Dimension

Major Depressive Disorder (MDD) and Bipolar Disorder (BD) are the most frequent mental disorders whose indeterminate etiopathogenesis spurs to explore new aetiologic scenarios. In light of the neuropsychiatric symptoms characterizing Cerebellar Cognitive Affective Syndrome (CCAS), the objective of this narrative review is to analyze the involvement of the cerebellum (Cbm) in the onset of these conditions. It aims at detecting the repercussions of the Cbm activities on mood disorders based on its functional subdivision in vestibulocerebellum (vCbm), pontocerebellum (pCbm) and spinocerebellum (sCbm). Despite the Cbm having been, for decades, associated with somato-motor functions, the described intercellular pathways, without forgiving the molecular impairment and the alteration in the volumetric relationships, make the Cbm a new important therapeutic target for MDD and BD. Given that numerous studies have showed its activation during mnestic activities and socio-emotional events, this review highlights in the Cbm, in which the altered external space perception (vCbm) is strictly linked to the cognitive-limbic Cbm (pCbm and sCbm), a crucial role in the MDD and BD pathogenesis. Finally, by the analysis of the cerebellar activity, this study aims at underlying not only the Cbm involvement in affective disorders, but also its role in social relationship building.

The Importance of α-Klotho in Depression and Cognitive Impairment and Its Connection to Glutamate Neurotransmission-An Up-to-Date Review

Depression is a serious neuropsychiatric disease affecting an increasing number of people worldwide. Cognitive deficits (including inattention, poor memory, and decision-making difficulties) are common in the clinical picture of depression. Cognitive impairment has been hypothesized to be one of the most important components of major depressive disorder (MDD; referred to as clinical depression), although typical cognitive symptoms are less frequent in people with depression than in people with schizophrenia or bipolar disorder (BD; sometimes referred to as manic-depressive disorder). The importance of α-Klotho in the aging process has been well-documented. Growing evidence points to the role of α-Klotho in regulating other biological functions, including responses to oxidative stress and the modulation of synaptic plasticity. It has been proven that a Klotho deficit may contribute to the development of various nervous system pathologies, such as behavioral disorders or neurodegeneration. Given the growing evidence of the role of α-Klotho in depression and cognitive impairment, it is assumed that this protein may be a molecular link between them. Here, we provide a research review of the role of α-Klotho in depression and cognitive impairment. Furthermore, we propose potential mechanisms (related to oxidative stress and glutamatergic transmission) that may be important in α-Klotho-mediated regulation of mental and cognitive function.

Dextromethorphan-Bupropion for the Treatment of Depression: A Systematic Review of Efficacy and Safety in Clinical Trials

BACKGROUND

A significant proportion of adults with major depressive disorder (MDD) do not respond to treatments which are currently used in clinical practice such as first-generation monoamine-based antidepressants.

OBJECTIVES

The objective of this systematic review was to assess the efficacy, safety, and mechanisms of action of AXS-05, a combination of the NMDA-receptor antagonist dextromethorphan with bupropion, in adults with MDD.

METHODS

We searched PubMed, Embase, Google Scholar, and ClinicalTrials.gov for current studies reporting on efficacy and/or safety of AXS-05 in patients with MDD. The search terms included: "AXS-05" OR "dextromethorphan and bupropion" AND "depression". Studies from database inception to January 2023 were evaluated. Risk of bias was assessed using the Cochrane Risk of Bias tool.

RESULTS

The search yielded 54 studies of which 5 were included. All studies had low risk of bias. Depression severity, measured with the Montgomery-Åsberg Depression Rating Scale (MADRS) significantly decreased as early as 1-week post-treatment from baseline when compared to a placebo-controlled group (LS mean difference 2.2; 95% CI 0.6-3.9; p = 0.007) and at 2 weeks compared to an active control group (LS mean difference 4.7; 95% CI 0.6-8.8; p = 0.024). Treatment efficacy could be maintained for up to 12 months with mean MADRS score reduction of 23 points from baseline. Clinical remission and response rates also improved at week 1 and were maintained for 12 months. The treatment was well-tolerated, with some transient adverse events reported.

CONCLUSION

Current evidence suggests that the combination of dextromethorphan and bupropion is a well-tolerated, rapid-acting treatment option for adults with MDD. Initial success with AXS-05 supports the mechanistic role of glutamatergeric and sigma 1 signaling in the pathophysiology of MDD.

Neuroimmunology of rabies: New insights into an ancient disease

Rabies is an ancient neuroinvasive viral (genus Lyssavirus, family Rhabdoviridae) disease affecting approximately 59,000 people worldwide. The central nervous system (CNS) is targeted, and rabies has a case fatality rate of almost 100% in humans and animals. Rabies is entirely preventable through proper vaccination, and thus, the highest incidence is typically observed in developing countries, mainly in Africa and Asia. However, there are still cases in European countries and the United States. Recently, demographic, increasing income levels, and the coronavirus disease 2019 (COVID-19) pandemic have caused a massive raising in the animal population, enhancing the need for preventive measures (e.g., vaccination, surveillance, and animal control programs), postexposure prophylaxis, and a better understanding of rabies pathophysiology to identify therapeutic targets, since there is no effective treatment after the onset of clinical manifestations. Here, we review the neuroimmune biology and mechanisms of rabies. Its pathogenesis involves a complex and poorly understood modulation of immune and brain functions associated with metabolic, synaptic, and neuronal impairments, resulting in fatal outcomes without significant histopathological lesions in the CNS. In this context, the neuroimmunological and neurochemical aspects of excitatory/inhibitory signaling (e.g., GABA/glutamate crosstalk) are likely related to the clinical manifestations of rabies infection. Uncovering new links between immunopathological mechanisms and neurochemical imbalance will be essential to identify novel potential therapeutic targets to reduce rabies morbidity and mortality.

Excitatory and inhibitory neurometabolites in anorexia nervosa: A systematic review of proton magnetic resonance spectroscopy studies

The dysregulation of excitatory and inhibitory neurotransmission is considered a pathological marker of Anorexia Nervosa (AN), however, no systematic evaluation of the proton Magnetic Resonance Spectroscopy (1H-MRS) literature has been conducted to date. Accordingly, we conducted a systematic review of neurometabolite differences between individuals with AN and healthy controls (HC). A comprehensive database search (until June 2023) identified seven studies meeting inclusion criteria. Samples included adolescents and adults with similar mean age (AN: 22.20 HC: 22.60), and female percentages (AN: 98%; HC: 94%). The review found a considerable need for improving study design and the reporting of MRS sequence parameters and analysis. Reduced glutamate concentrations in the ACC and OCC, and reduced Glx concentrations in the ACC were reported by one and two studies, respectively. Lastly, only one study to date has quantified GABA concentrations, with no significant differences found. In conclusion, there is currently insufficient evidence of excitatory and inhibitory neurometabolites changes in AN. As the 1H-MRS literature in AN increases, the key questions herein proposed must be revisited.

Coriandrum sativum and Its Utility in Psychiatric Disorders

The negative impact on worldwide social well-being by the increasing rate of psychiatric diseases has led to a continuous new drug search. Even though the current therapeutic options exert their activity on multiple neurological targets, these have various adverse effects, causing treatment abandonment. Recent research has shown that Coriandrum sativum offers a rich source of metabolites, mainly terpenes and flavonoids, as useful agents against central nervous system disorders, with remarkable in vitro and in vivo activities on models related to these pathologies. Furthermore, studies have revealed that some compounds exhibit a chemical interaction with γ-aminobutyric acid, 5-hydroxytryptamine, and N-methyl-D-aspartate receptors, which are key components in the pathophysiology associated with psychiatric and neurological diseases. The current clinical evaluations of standardized extracts of C. sativum are scarce; however, one or more of its compounds represents an area of opportunity to test the efficacy of the plant as an anxiolytic, antidepressant, antiepileptic, or sleep enhancer. For this, the aim of the review was based on the pharmacological activities offered by the compounds identified and isolated from coriander and the processes involved in achieving their effect. In addition, lines of technological research, like molecular docking and nanoparticles, are proposed for the future development of phytomedicines, based on the bioactive molecules of C. sativum, for the treatment of psychiatric and neurological disorders addressed in the present study.