Finding the intracellular signaling pathways affected by mood disorder treatments

Reversing anxiety by targeting a stress-responsive signaling pathway

Current treatments of anxiety and depressive disorders are plagued by considerable side effects and limited efficacies, underscoring the need for additional molecular targets that can be leveraged to improve medications. Here, we have identified a molecular cascade triggered by chronic stress that exacerbates anxiety- and depressive-like behaviors. Specifically, chronic stress enhances Src kinase activity and tyrosine phosphorylation of calmodulin, which diminishes MyosinVa (MyoVa) interaction with Neuroligin2 (NL2), resulting in decreased inhibitory transmission and heightened anxiety-like behaviors. Importantly, pharmacological inhibition of Src reinstates inhibitory synaptic deficits and effectively reverses heightened anxiety-like behaviors in chronically stressed mice, a process requiring the MyoVa-NL2 interaction. These data demonstrate the reversibility of anxiety- and depressive-like phenotypes at both molecular and behavioral levels and uncover a therapeutic target for anxiety and depressive disorders.

Two polygenic mouse models of major depressive disorders identify TMEM161B as a potential biomarker of disease in humans

Treatments are only partially effective in major depressive disorders (MDD) but no biomarker exists to predict symptom improvement in patients. Animal models are essential tools in the development of antidepressant medications, but while recent genetic studies have demonstrated the polygenic contribution to MDD, current models are limited to either mimic the effect of a single gene or environmental factor. We developed in the past a model of depressive-like behaviors in mice (H/Rouen), using selective breeding based on behavioral reaction after an acute mild stress in the tail suspension test. Here, we propose a new mouse model of depression (H-TST) generated from a more complex genetic background and based on the same selection process. We first demonstrated that H/Rouen and H-TST mice had similar phenotypes and were more sensitive to glutamate-related antidepressant medications than selective serotonin reuptake inhibitors. We then conducted an exome sequencing on the two mouse models and showed that they had damaging variants in 174 identical genes, which have also been associated with MDD in humans. Among these genes, we showed a higher expression level of Tmem161b in brain and blood of our two mouse models. Changes in TMEM161B expression level was also observed in blood of MDD patients when compared with controls, and after 8-week treatment with duloxetine, mainly in good responders to treatment. Altogether, our results introduce H/Rouen and H-TST as the two first polygenic animal models of MDD and demonstrate their ability to identify biomarkers of the disease and to develop rapid and effective antidepressant medications.

Association of BDNF risk variant and dorsolateral cortical thickness with long-term treatment response to valproate in type I bipolar disorder: An exploratory study

Valproate is among the most prescribed drugs for bipolar disorder; however, 87% of patients do not report full long-term treatment response (LTTR) to this medication. One of valproate's suggested mechanisms of action involves the brain-derived neurotrophic factor (BDNF), expressed in the brain areas regulating emotions, such as the prefrontal cortex. Nonetheless, data about the role of BDNF in LTTR and its implications in the structure of the dorsolateral prefrontal cortex (dlPFC) is scarce. We explore the association of BDNF variants and dorsolateral cortical thickness (CT) with LTTR to valproate in bipolar disorder type I (BDI). Twenty-eight BDI patients were genotyped for BDNF polymorphisms rs1519480, rs6265, and rs7124442, and T1-weighted 3D brain scans were acquired. LTTR to valproate was evaluated with Alda's scale. A logistic regression analysis was conducted to evaluate LTTR according to BDNF genotypes and CT. We evaluated CT differences by genotypes with analysis of covariance. LTTR was associated with BDNF rs1519480 and right dlPFC thickness. Insufficient responders with the CC genotype had thicker right dlPFC than TC and TT genotypes. Full responders reported thicker right dlPFC in TC and TT genotypes. In conclusion, different patterns of CT related to BDNF genotypes were identified, suggesting a potential biomarker of LTTR to valproate in our population.

Clinical value and mechanistic analysis of HIIT on modulating risk and symptoms of depression: A systematic review

Background

The exact causal mechanisms of depression remain unclear due to the complexity of the triggers, which has led to limitations in treating depression using modern drugs. High-intensity interval training (HIIT) is as effective as medication in treating depression without toxic side effects. Typically, HIIT requires less time commitment (i.e., shorter exercise duration) and exhibits pronounced benefits on depressive symptoms than other forms of physical exercise. This review summarizes the risk reduction and clinical effects of HIIT for depression and discusses the underlying mechanisms, providing a theoretical basis for utilizing HIIT in treating depression.

Methods

A database search was conducted in PubMed, Embase, Web of Science, and Scopus from inception up to October 2022. The methodological quality of the included literature was evaluated by the physiotherapy evidence database (PEDro) scale criteria. The review focused on evaluating the changes in depression risk or symptoms of HIIT interventions in healthy individuals, patients with depression, and patients with other disorders co-morbid with depression. Consequently, the mechanisms associated with depression related HIIT were summarized.

Results

A total of 586 participants (52 % female; mean age: 43.58±8.93 years) from 22 studies were included. Implementing HIIT using different exercise types alleviates depressive symptoms in individuals with depression and in individuals with depression who have exhibited comorbidities and reduced depression scale scores in subjects immediately after acute exercise. In addition, the long-interval HIIT and short-interval HIIT in the treatment of patients with cardiovascular or psychiatric disorders may reduce depressive symptoms via complex exercise-related changes on several levels, including by effecting the following measures: releasing monoamines, reducing neuronal death, inducing neurogenesis, modulating the functional homeostasis of the HPA axis, and enhancing the level of inflammation in the body.

Conclusion

HIIT is a relatively safe and effective antidepressant, which may involve multiple neurobiological mechanisms (release of monoamines, reducing neuronal death, inducing neurogenesis, modulating the functional homeostasis of the HPA axis, and enhancing the level of inflammation in the body), thereby reducing the risk or symptoms of depression in participants.

Psychedelics: preclinical insights provide directions for future research

Recently, psychedelics have emerged as promising therapeutics for numerous neuropsychiatric disorders. While their potential in the clinic has yet to be fully elucidated, understanding their molecular and biological mechanisms is imperative as these compounds are becoming widely used both in therapeutic and recreational contexts. This review examines the current understanding of basic biology, pharmacology, and structural biology in an attempt to reveal both the knowns and unknowns within the field.

Effects of electroconvulsive therapy on cerebral A1 adenosine receptor availability: a PET study in patients suffering from treatment-resistant major depressive disorder

Introduction

Sleep deprivation and electroconvulsive therapy (ECT) effectively ameliorate symptoms in major depressive disorder (MDD). In rodents, both are associated with an enhancement of cerebral adenosine levels, which in turn likely influence adenosinergic receptor expression. The aim of the current study was to investigate cerebral A1 adenosine receptor (A1AR) availability in patients with MDD as a potential mediating factor of antidepressant effects of ECT using [18F]CPFPX and positron emission tomography (PET).

Methods

Regional A1AR availability was determined before and after a series of ECT applications (mean number ± SD 10.4 ± 1.2) in 14 subjects (4 males, mean age 49.5 ± 11.8 years). Clinical outcome, measured by neuropsychological testing, and ECT parameters were correlated with changes in A1AR availability.

Results

ECT had a strong antidepressive effect (p < 0.01) while on average cerebral A1AR availability remained unaltered between pre-and post-ECT conditions (F = 0.65, p = 0.42, mean difference ± SD 3.93% ± 22.7%). There was no correlation between changes in clinical outcome parameters and regional A1AR availability, although individual patients showed striking bidirectional alterations of up to 30-40% in A1AR availability after ECT. Solely, for the mean seizure quality index of the applied ECTs a significant association with changes in A1AR availability was found (rs = -0.6, p = 0.02).

Discussion

In the present study, therapeutically effective ECT treatment did not result in coherent changes of A1AR availability after a series of ECT treatments. These findings do not exclude a potential role for cerebral A1ARs in ECT, but shift attention to rather short-termed and adaptive mechanisms during ECT-related convulsive effects.

Antidepressant effects of total alkaloids of Fibraurea recisa on improving corticosterone-induced apoptosis of HT-22 cells and chronic unpredictable mild stress-induced depressive-like behaviour in mice

CONTEXT

Fibraurea recisa Pierre. (Menispermaceae) (FR) is a traditional Chinese medicine known as "Huangteng." The total alkaloids of FR (AFR) are the main active ingredients. However, the pharmacological effects of AFR in the treatment of depression have not been reported.

OBJECTIVES

This study investigates the antidepressant effects of AFR by network pharmacology and verification experiments.

MATERIALS AND METHODS

Compound-Target-Pathway (C-P-T) network of FR and depression was constructed through network pharmacology. In vitro, HT-22 cells were treated with corticosterone (CORT) solution (0.35 mg/mL), then AFR (0.05 mg/mL) solution and inhibitor AZD6244 (14 μM/mL) or BAY11-7082 (10 μM/mL) were added, respectively. The cell viability was detected by CCK-8. In vivo, C57BL/6 mice were divided into 5 groups, namely the normal group, the CUMS group, the AFR (400 mg/kg) group, and the 2 groups that were simultaneously administered the inhibitory group AZD6244 (8 mg/kg) and BAY11-7082 (5 mg/kg). Western blotting was used to assess the expression level of the proteins.

RESULTS

AFR could protect HT-22 cells from CORT-induced damage and increase the cell viability from 49.12 ± 3.4% to 87.26 ± 1.5%. Moreover, AFR significantly increased the levels of BDNF (1.3, 1.4-fold), p-ERK (1.4, 1.2-fold) and p-CERB (1.6, 1.3-fold), and decreased the levels of NLRP3 (11.3%, 31.6%), ASC (19.2%, 34.2%) and caspase-1 (18.0%, 27.6%) in HT-22 cells and the hippocampus, respectively.

DISCUSSION AND CONCLUSIONS

AFR can improve depressive-like behaviours and can develop drugs for depression treatment. Further studies are needed to validate its potential in clinical medicine.

Gene Expression Profile Associated with Asmt Knockout-Induced Depression-Like Behaviors and Exercise Effects in Mouse Hypothalamus

Sleep disorder caused by abnormal circadian rhythm is one of the main symptoms and risk factors of depression. As a known hormone regulating circadian rhythms, melatonin (MT) is also namely N-acetyl-5-methoxytryptamine. N-acetylserotonin methyltransferase (Asmt) is the key rate-limiting enzyme of MT synthesis and has been reportedly associated with depression. Although 50–90% of patients with depression have sleep disorders, there are no effective treatment ways in the clinic. Exercise can regulate circadian rhythm and play an important role in depression treatment. In the present study, we showed that Asmt knockout induced depression-like behaviors, which were ameliorated by swimming exercise. Moreover, swimming exercise increased serum levels of MT and 5-hydroxytryptamine (5-HT) in Asmt knockout mice. In addition, the microarray data identified 10 differentially expressed genes (DEGs) in KO mice compared with WT mice and 29 DEGs in KO mice after swimming exercise. Among the DEGs, the direction and magnitude of change in epidermal growth factor receptor pathway substrate 8-like 1 (Eps8l1) and phospholipase C-β 2 (Plcb2) were confirmed by qRT-PCR partly. Subsequent bioinformatic analysis showed that these DEGs were enriched significantly in the p53 signaling pathway, long-term depression and estrogen signaling pathway. In the protein–protein interaction (PPI) networks, membrane palmitoylated protein 1 (Mpp1) and p53-induced death domain protein 1 (Pidd1) were hub genes to participate in the pathological mechanisms of depression and exercise intervention. These findings may provide new targets for the treatment of depression.

Gadd45 in Neuronal Development, Function, and Injury

The growth arrest and DNA damage-inducible (Gadd) 45 proteins have been associated with numerous cellular mechanisms including cell cycle control, DNA damage sensation and repair, genotoxic stress, neoplasia, and molecular epigenetics. The genes were originally identified in in vitro screens of irradiation- and interleukin-induced transcription and have since been implicated in a host of normal and aberrant central nervous system processes. These include early and postnatal development, injury, cancer, memory, aging, and neurodegenerative and psychiatric disease states. The proteins act through a variety of molecular signaling cascades including the MAPK cascade, cell cycle control mechanisms, histone regulation, and epigenetic DNA demethylation. In this review, we provide a comprehensive discussion of the literature implicating each of the three members of the Gadd45 family in these processes.

The promises and perils of psychedelic pharmacology for psychiatry

Psychedelic drugs including psilocybin, N,N'-dimethyltryptamine (DMT) and lysergic acid diethylamide (LSD) are undergoing a renaissance as potentially useful drugs for various neuropsychiatric diseases, with a rapid onset of therapeutic activity. Notably, phase II trials have shown that psilocybin can produce statistically significant clinical effects following one or two administrations in depression and anxiety. These findings have inspired a 'gold rush' of commercial interest, with nearly 60 companies already formed to explore opportunities for psychedelics in treating diverse diseases. Additionally, these remarkable phenomenological and clinical observations are informing hypotheses about potential molecular mechanisms of action that need elucidation to realize the full potential of this investigative space. In particular, despite compelling evidence that the 5-HT_2A receptor is a critical mediator of the behavioural effects of psychedelic drugs, uncertainty remains about which aspects of 5-HT_2A receptor activity in the central nervous system are responsible for therapeutic effects and to what degree they can be isolated by developing novel chemical probes with differing specificity and selectivity profiles. Here, we discuss this emerging area of therapeutics, covering both controversies and areas of consensus related to the opportunities and perils of psychedelic and psychedelic-inspired therapeutics. We highlight how basic science breakthroughs can guide the discovery and development of psychedelic-inspired medications with the potential for improved efficacy without hallucinogenic or rewarding actions.

Distinctively lower DISC1 mRNA levels in patients with schizophrenia, especially in those with higher positive, negative, and depressive symptoms

BACKGROUND

The issue of genetic influence on schizophrenia has received considerable attention. The DISC1 gene has been shown in several studies to play a role in the pathophysiology of schizophrenia. However, the relationship between DISC1 mRNA expression vs. schizophrenia and its clinical symptoms is uncertain.

METHODS

Fifty-six subjects (32 patients with schizophrenia and 24 healthy controls) were enrolled. Peripheral blood was obtained from all subjects to exam the DISC1 mRNA expression. Schizophrenia patients were evaluated with Hamilton Rating Scale for Depression (HAMD), Positive and Negative Syndrome Scale (PANSS), Brief Psychiatric Rating Scale (BPRS) and Scale for the Assessment of Negative Symptoms (SANS) scales. Healthy subjects were assessed with HAMD scale.

RESULTS

Patients with schizophrenia had significantly lower levels of the DISC1 mRNA expression than the healthy control (P = 0.002). We also found that lower DISC1 mRNA levels in schizophrenia patients were associated with higher degree of depression in HAMD (P = 0.037), severer positive symptoms in PANSS (P = 0.032) and more negative symptoms in SANS (P = 0.038).

CONCLUSION

The results showed that schizophrenia patients had lower levels of DISC1 mRNA than healthy individuals, and that the schizophrenia patients with lower DISC1 mRNA levels were more likely to manifest more marked symptoms, including positive, negative, and depressive symptoms. The findings suggest that lower DISC1 expression may be related with the pathogenesis and phenotypes of schizophrenia. Future studies are needed to replicate the results and to further establish its potential role in clinical application of early diagnosis and outcome follow-up.

β-Arrestin-dependent ERK signaling reduces anxiety-like and conditioned fear-related behaviors in mice

G protein-coupled receptors (GPCRs) are implicated in the regulation of fear and anxiety. GPCR signaling involves canonical G protein pathways but can also engage downstream kinases and effectors through scaffolding interactions mediated by β-arrestin. Here, we investigated whether β-arrestin signaling regulates anxiety-like and fear-related behavior in mice in response to activation of the GPCR δ-opioid receptor (δOR or DOR). Administration of β-arrestin-biased δOR agonists to male C57BL/6 mice revealed β-arrestin 2-dependent activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in the dorsal hippocampus and amygdala and β-arrestin 1-dependent activation of ERK1/2 in the nucleus accumbens. In mice, β-arrestin-biased agonist treatment was associated with reduced anxiety-like and fear-related behaviors, with some overlapping and isoform-specific input. In contrast, applying a G protein-biased δOR agonist decreased ERK1/2 activity in all three regions as well as the dorsal striatum and was associated with increased fear-related behavior without effects on baseline anxiety. Our results indicate a complex picture of δOR neuromodulation in which β-arrestin 1- and 2-dependent ERK signaling in specific brain subregions suppresses behaviors associated with anxiety and fear and opposes the effects of G protein-biased signaling. Overall, our findings highlight the importance of noncanonical β-arrestin-dependent GPCR signaling in the regulation of these interrelated emotions.

TGF-β/Smad Signalling in Neurogenesis: Implications for Neuropsychiatric Diseases

TGF-β/Smad signalling has been the subject of extensive research due to its role in the cell cycle and carcinogenesis. Modifications to the TGF-β/Smad signalling pathway have been found to produce disparate effects on neurogenesis. We review the current research on canonical and non-canonical TGF-β/Smad signalling pathways and their functions in neurogenesis. We also examine the observed role of neurogenesis in neuropsychiatric disorders and the relationship between TGF-β/Smad signalling and neurogenesis in response to stressors. Overlapping mechanisms of cell proliferation, neurogenesis, and the development of mood disorders in response to stressors suggest that TGF-β/Smad signalling is an important regulator of stress response and is implicated in the behavioural outcomes of mood disorders.

Ginseng polysaccharides: A potential neuroprotective agent

The treatments of nervous system diseases (NSDs) have long been difficult issues for researchers because of their complexity of pathogenesis. With the advent of aging society, searching for effective treatments of NSDs has become a hot topic. Ginseng polysaccharides (GP), as the main biologically active substance in ginseng, has various biological properties in immune-regulation, anti-oxidant, anti-inflammation and etc. Considering the association between the effects of GP and the pathogenesis of neurological disorders, many related experiments have been conducted in recent years. In this paper, we reviewed previous studies about the effects and mechanisms of GP on diseases related to nervous system. We found GP play an ameliorative role on NSDs through the regulation of immune system, inflammatory response, oxidative damage and signaling pathway. Structure-activity relationship was also discussed and summarized. In addition, we provided new insights into GP as promising neuroprotective agent for its further development and utilization.

New Pharmacological Interventions in Bipolar Disorder

The biological bases of bipolar disorder include aspects related, among others, to neurohormonal pathways, neurotransmission, signal transduction, regulation of gene expression, oxidative stress, neuroplasticity, and changes in the immune system. There is still a gap in understanding its complex neurobiology and, consequently, developing new treatments. Multiple factors probably interact in this complex equation of pathophysiology of bipolar disorder, such as genetic, biochemical, psychosocial, and environmental stress events, correlating with the development and severity of the bipolar disorder. These mechanisms can interact to exacerbate inflammation, impair neurogenesis, and increase oxidative stress damage, cellular mitochondrial dysfunction, changes in neurotrophins and in epigenetic mechanisms, neuroendocrine dysfunction, activation of neuronal death pathways, and dysfunction in neurotransmission systems. In this review, we explore the up-to-date knowledge of the neurobiological underpinnings of bipolar disorders. The difficulty in developing new drugs for bipolar disorder is very much associated with the lack of knowledge about the precise pathophysiology of this disorder. Pharmacological treatment for bipolar patients is vital; to progress to effective medications, it is essential to understand the neurobiology in bipolar patients better and identify novel therapeutic targets.

Negative relationship between brain α1A-AR neurotransmission and βArr2 levels in anxious adolescent rats subjected to early life stress

Early-life stress is correlated with the development of anxiety-related behavior in adolescence, but underlying mechanisms remain poorly known. The α_1A-adrenergic receptor (AR) is linked to mood regulation and its function is assumed to be regulated by β-arrestins (βArrs) via desensitization and downregulation. Here, we investigated correlation between changes in α_1A-AR and βArr2 levels in the prefrontal cortex (PFC) and hippocampus of adolescent and adult male rats subjected to maternal separation (MS) and their relationship with anxiety-like behavior in adolescence. MS was performed 3 h per day from postnatal days 2-11 and anxiety-like behavior was evaluated in the elevated plus-maze and open field tests. The protein levels were examined using western blot assay. MS decreased α_1A-AR expression and increased βArr2 expression in both brain regions of adolescent rats, while induced reverse changes in adulthood. MS adolescent rats demonstrated higher anxiety-type behavior and lower activity in behavioral tests than controls. Decreased α_1A-AR levels in MS adolescence strongly correlated with reduced time spent in the open field central area, consistent with increased anxiety-like behavior. An anxiety-like phenotype was mimicked by acute and chronic treatment of developing rats with prazosin, an α_1A-AR antagonist, suggesting α_1A-AR downregulation may facilitate anxiety behavior in MS adolescent rats. Together, our results indicate a negative correlation between α_1A-AR neurotransmission and βArr2 levels in both adults and anxious-adolescent rats and suggest that increased βArr2 levels may contribute to posttranslational regulation of α_1A-AR and modulation of anxiety-like behavior in adolescent rats. This may provide a path to develop more effective anxiolytic treatments.

Predicted Cellular and Molecular Actions of Lithium in the Treatment of Bipolar Disorder: An In Silico Study

BACKGROUND

Lithium remains the first-line treatment for bipolar disorder (BD), but patients respond to it variably. While a myriad of studies have attributed many genes and signaling pathways to lithium responsiveness, a comprehensive study with an integrated conclusion is still lacking.

OBJECTIVE

We aim to present an integrated mechanism for the therapeutic actions of lithium in BD.

METHODS

First, a list of lithium responsiveness-associated genes (LRAGs) was collected by searching in the literature. Thereafter, gene set enrichment analysis together with gene-gene interaction network analysis was performed, in order to find the cellular and molecular events related to the LRAGs.

RESULTS

Gene set enrichment analyses showed that the chromosomal regions 3p26, 4p21, 5q34 and 7p13 could be novel associated loci for lithium responsiveness in BD. Also, expression pattern analysis of the LRAGs showed their enrichment in adulthood stages and different cell lineages of brain, blood and immune system. Most of the LRAGs exhibited enriched expression in central parts of human brain, suggesting major contribution of these parts in lithium responsiveness. Beside the prediction of several biological processes and signaling pathways related to lithium responsiveness, an interaction network between these processes was constructed that was found to be regulated by a set of microRNAs. Proteins of the network were mainly classified as transcription factors and kinases, which also highlighted the crucial role of glycogen synthase kinase 3β (GSK3β) in lithium responsiveness.

CONCLUSIONS

The predicted cellular and molecular events in this study could be considered as mechanisms and also determinants of lithium responsiveness in BD.

Wnt/β-Catenin Signaling in Neural Stem Cell Homeostasis and Neurological Diseases

Neural stem/progenitor cells (NSCs) maintain the ability of self-renewal and differentiation and compose the complex nervous system. Wnt signaling is thought to control the balance of NSC proliferation and differentiation via the transcriptional coactivator β-catenin during brain development and adult tissue homeostasis. Disruption of Wnt signaling may result in developmental defects and neurological diseases. Here, we summarize recent findings of the roles of Wnt/β-catenin signaling components in NSC homeostasis for the regulation of functional brain circuits. We also suggest that the potential role of Wnt/β-catenin signaling might lead to new therapeutic strategies for neurological diseases, including, but not limited to, spinal cord injury, Alzheimer's disease, Parkinson's disease, and depression.

The antidepressant-like effect of guanosine is dependent on GSK-3β inhibition and activation of MAPK/ERK and Nrf2/heme oxygenase-1 signaling pathways

Although guanosine is an endogenous nucleoside that displays antidepressant-like properties in several animal models, the mechanism underlying its antidepressant-like effects is not well characterized. The present study aimed at investigating the involvement of ERK/GSK-3β and Nrf2/HO-1 signaling pathways in the antidepressant-like effect of guanosine in the mouse tail suspension test (TST). The immobility time in the TST was taken as an indicative of antidepressant-like responses and the locomotor activity was assessed in the open-field test. Biochemical analyses were performed by Western blotting in the hippocampus and prefrontal cortex (PFC). The combined treatment with sub-effective doses of guanosine (0.01 mg/kg, p.o.) and lithium chloride (a non-selective GSK-3β inhibitor, 10 mg/kg, p.o.) or AR-A014418 (selective GSK-3β inhibitor, 0.01 μg/site, i.c.v.) produced a synergistic antidepressant-like effect in the TST. The antidepressant-like effect of guanosine (0.05 mg/kg, p.o.) was completely prevented by the treatment with MEK1/2 inhibitors U0126 (5 μg/site, i.c.v.), PD98059 (5 μg/site, i.c.v.), or zinc protoporphyrin IX (ZnPP) (HO-1 inhibitor, 10 μg/site, i.c.v). Guanosine administration (0.05 mg/kg, p.o.) increased the immunocontent of β-catenin in the nuclear fraction and Nrf2 in the cytosolic fraction in the hippocampus and PFC. The immunocontent of HO-1 was also increased in the hippocampus and PFC. Altogether, the results provide evidence that the antidepressant-like effect of guanosine in the TST involves the inhibition of GSK-3β, as well as activation of MAPK/ERK and Nrf2/HO-1 signaling pathways, highlighting the relevance of these molecular targets for antidepressant responses.

Melatonin ameliorates anxiety and depression-like behaviors and modulates proteomic changes in triple transgenic mice of Alzheimer's disease

Alzheimer's disease (AD) is a devastating neurodegenerative disease accompanied by neuropsychiatric symptoms, such as anxiety and depression. The levels of melatonin decrease in brains of AD patients. The potential effect of melatonin on anxiety and depression behaviors in AD and the underlying mechanisms remain unclear. In this study, we treated 10-month-old triple transgenic mice of AD (3xTg-AD) with melatonin (10 mg/kg body weight/day) for 1 month and explored the effects of melatonin on anxiety and depression-like behaviors in 3xTg-AD mice and the protein expression of hippocampal tissues. The behavioral test showed that melatonin ameliorated anxiety and depression-like behaviors of 3xTg-AD mice as measured by open field test, elevated plus maze test, forced swimming test, and tail suspension test. By carrying out two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) coupled with mass spectrometry, we revealed a total of 46 differentially expressed proteins in hippocampus between the wild-type (WT) mice and non-treated 3xTg-AD mice. A total of 21 differentially expressed proteins were revealed in hippocampus between melatonin-treated and non-treated 3xTg-AD mice. Among these differentially expressed proteins, glutathione S-transferase P 1 (GSTP1) (an anxiety-associated protein) and complexin-1 (CPLX1) (a depression-associated protein) were significantly down-regulated in hippocampus of 3xTg-AD mice compared with the WT mice. The expression of these two proteins was modulated by melatonin treatment. Our study suggested that melatonin could be used as a potential candidate drug to improve the neuropsychiatric behaviors in AD via modulating the expression of the proteins (i.e. GSTP1 and CPLX1) involved in anxiety and depression behaviors. © 2017 BioFactors, 43(4):593-611, 2017.

Involvement of Akt/GSK3β/CREB signaling pathway on chronic omethoate induced depressive-like behavior and improvement effects of combined lithium chloride and astaxanthin treatment

Chronic organophosphorus pesticides (OP) exposure is associated with an increased risk of depression, and there is an urgent need to find an effective treatment for the depressive-like symptoms caused by OP. The main purpose of this study was to investigate whether combined lithium chloride (LiCl) and astaxanthin (AST) treatment would manifest synergetic antidepressant effects on mice with chronic OP exposure, and to determine the role of the Akt/GSK3β/CREB signaling pathway. Our results showed that chronic omethoate exposure significantly increased immobility time in behavioral tests and induced neuron damage in HE staining. The expression of p-GSK3β, p-CREB, p-PI3K and p-Akt in hippocampus after OP exposure were significantly down-regulated, while the influences were reversed by LiCl and AST treatment. Moreover, the combined application of AST and LiCl had synergistic therapeutic effects compared to LiCl and AST treatment alone, the expression of p-GSK3β, p-CREB, p-PI3K and p-Akt after combined LiCl-AST treatment were significantly higher than that with single drug application. These results showed that the combination of LiCl and AST could efficiently ameliorate depressive-like behavior induced by omethoate, and Akt/GSK3β/CREB signaling pathway might be responsible for the neuroprotective effect.

The influence of TSA and VPA on the in vitro differentiation of bone marrow mesenchymal stem cells into neuronal lineage cells: Gene expression studies

INTRODUCTION

Epigenetic mechanisms regulate the transcription of genes, which can affect the differentiation of MSCs. The aim of the current work is to determine how the histone deacetylase inhibitors TSA and VPA affect the expression of neuronal lineage genes in a culture of rat MSCs (rMSCs).

MATERIALS AND METHODS

We analyzed the expression of early neuron marker gene (Tubb3), mature neuron markers genes (Vacht, Th, Htr2a) and the oligodendrocyte progenitor marker gene (GalC). Moreover, changes in the gene expression after three different periods of exposure to TSA and VPA were investigated for the first time.

RESULTS

After six days of exposition to TSA and VPA, the expression of Tubb3 and GalC decreased, while the expression of Th increased. The highest increase of VAChT expression was observed after three days of TSA and VPA treatment. A decrease in Htr2a gene expression was observed after TSA treatment and an increase was observed after VPA treatment. We also observed that TSA and VPA inhibited cell proliferation and the formation of neurospheres in the rMSCs culture.

DISCUSSION

The central findings of our study are that TSA and VPA affect the expression of neuronal lineage genes in an rMSCs culture. After exposure to TSA or VPA, the expression of early neuronal gene decreases but equally the expression of mature neuron genes increases. After TSA and VPA treatment ER of the oligodendrocyte progenitor marker decreased. TSA and VPA inhibit cell proliferation and the formation of neurospheres in rMSCs culture.

Possible target-related proteins of stress-resistant rats suggested by label-free proteomic analysis

Stress plays a crucial role in the development of major depressive disorder, but the molecular mechanism underlying the susceptibility vs. resilience to stress remains unclear.

Circadian Gene Circuitry Predicts Hyperactive Behavior in a Mood Disorder Mouse Model

Bipolar disorder, also known as manic-depressive illness, causes swings in mood and activity levels at irregular intervals. Such changes are difficult to predict, and their molecular basis remains unknown. Here, we use infradian (longer than a day) cyclic activity levels in αCaMKII (Camk2a) mutant mice as a proxy for such mood-associated changes. We report that gene-expression patterns in the hippocampal dentate gyrus could retrospectively predict whether the mice were in a state of high or low locomotor activity (LA). Expression of a subset of circadian genes, as well as levels of cAMP and pCREB, possible upstream regulators of circadian genes, were correlated with LA states, suggesting that the intrinsic molecular circuitry changes concomitant with infradian oscillatory LA. Taken together, these findings shed light onto the molecular basis of how irregular biological rhythms and behavior are controlled by the brain.

Drug Repurposing Is a New Opportunity for Developing Drugs against Neuropsychiatric Disorders

Better the drugs you know than the drugs you do not know. Drug repurposing is a promising, fast, and cost effective method that can overcome traditional de novo drug discovery and development challenges of targeting neuropsychiatric and other disorders. Drug discovery and development targeting neuropsychiatric disorders are complicated because of the limitations in understanding pathophysiological phenomena. In addition, traditional de novo drug discovery and development are risky, expensive, and time-consuming processes. One alternative approach, drug repurposing, has emerged taking advantage of off-target effects of the existing drugs. In order to identify new opportunities for the existing drugs, it is essential for us to understand the mechanisms of action of drugs, both biologically and pharmacologically. By doing this, drug repurposing would be a more effective method to develop drugs against neuropsychiatric and other disorders. Here, we review the difficulties in drug discovery and development in neuropsychiatric disorders and the extent and perspectives of drug repurposing.

Relationship between phosphoinositide-3-kinase genetic polymorphism and schizophrenia

Schizophrenia, with incidence of 1% worldwide, is a common mental disorder. Phosphoinositide-3-kinases (PI3Ks) are a family of enzymes involved in cellular functions such as cell growth, proliferation, differentiation, motility, intracellular trafficking, and survival. These enzymes play an important role in the PI3K/AKT signalling pathway. The PIK3CA gene encodes the alpha catalytic subunit of the PI3K enzyme. The present study analysed the role of three SNPs of the PIK3CA gene (rs6443624 (A/C), rs7640662(C/G) and rs7621329(C/T)) in the development of schizophrenia.

METHODS

In this case-controlled study, DNA was extracted from blood samples from 108 patients with schizophrenia and 108 healthy patients as controls. Genotypic analyses of PIK3CA SNPs rs6443624 (A/C), rs7640662(C/G) and rs7621329(C/T) were made using the tetra primer ARMS-PCR technique.

RESULTS

The outcome shows significant difference between CT and the combined genotype (CT + TT) of rs7621329 and the risk of schizophrenia (OR = 6.4, 95% CI = 3.023-14.23, p < 0.0001). Outcome showed no significant difference for were for analyses of the rs6443624 and rs7640662 genotypes.

CONCLUSIONS

These results indicate an association between PIK3CA gene polymorphism on the rs7621329(C/T) site and the risk of schizophrenia. Further study of the genetic population using a larger sample size is necessary in order to validate these present findings.

Activated immune-inflammatory pathways are associated with long-standing depressive symptoms: Evidence from gene-set enrichment analyses in the Young Finns Study

We used genome wide expression (GWE) data of circulating blood cells and pathway analysis to investigate the inflammatory and other molecular pathways that may be associated with long-standing depressive symptoms. Participants were 607 women and 316 men (mean age 42 years) from the Young Finns Study who participated in three consecutive study phases in 2001, 2007 and 2012. Using Gene-set enrichment analyses (GSEA) we focused our analyses to pathways (available in MSigDB database) that are likely to affect immunological and inflammatory processes. GSEA were performed for blood cell GWE data in 2012. Depressive symptoms were assessed using a modified 21-item Beck Depression Inventory in each of the three study phases. Participants who scored in the top quartile of depressive symptoms in each of the three measurement points (n = 191) differed from other participants (n = 732) in several gene-set pathways related to inflammatory processes or immune-inflammatory signaling including interleukin (IL-1) pathway, and pathways related to various immuno-inflammatory processes, such as toll-like, the NEF protein, the nuclear factor kB, the kinase AKT and the mature B cell antigen receptor pathway (false discovery rates, FDRs<0.12). The results provide novel genome wide molecular evidence that support the association between chronic depressive symptoms and altered immune-inflammatory regulation.

Alterations in Gene Expression in Depression: Prospects for Personalize Patient Treatment

The number of people around the world suffering from depression has dramatically increased in last few decades. It has been predicted that by 2020 depression will become the second most common cause of disability. Furthermore, depression is often misdiagnosed and confused with other psychiatric disorders showing similar symptoms, i.e., anxiety and bipolar disorder, due to the fact that diagnosing is often carried out by medical workers who are not psychiatrically trained. These facts prompt us to prepare this review which focuses on alterations in gene expression in depression. We believe that an in-depth knowledge of molecular bases of behavior in depression and other mood disorders would be of a great benefit for the correct diagnosing of these disorders, as well as for prescribing a treatment that best suits each individual depending on expression alterations in depression-related genes. Therefore, the main aim of this review is to promote further translational research on the biochemistry of mood disorders and take the results further for the design of new targeted therapeutics that can be used for personalized treatment with minimal adverse effects.

Antidepressants activate the lysophosphatidic acid receptor LPA(1) to induce insulin-like growth factor-I receptor transactivation, stimulation of ERK1/2 signaling and cell proliferation in CHO-K1 fibroblasts

Different lines of evidence indicate that the lysophosphatidic acid (LPA) receptor LPA1 is involved in neurogenesis, synaptic plasticity and anxiety-related behavior, but little is known on whether this receptor can be targeted by neuropsychopharmacological agents. The present study investigated the effects of different antidepressants on LPA1 signaling. We found that in Chinese hamster ovary (CHO)-K1 fibroblasts expressing endogenous LPA1 tricyclic and tetracyclic antidepressants and fluoxetine induced the phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2) and CREB. This response was antagonized by either LPA1 blockade with Ki16425 and AM966 or knocking down LPA1 with siRNA. Antidepressants induced ERK1/2 phosphorylation in human embryonic kidney (HEK)-293 cells overexpressing LPA1, but not in wild-type cells. In PathHunter™ assay measuring receptor-β-arrestin interaction, amitriptyline, mianserin and fluoxetine failed to induce activation of LPA2 and LPA3 stably expressed in CHO-K1 cells. ERK1/2 stimulation by antidepressants and LPA was suppressed by pertussis toxin and inhibition of Src, phosphatidylinositol-3 kinase and insulin-like growth factor-I receptor (IGF-IR) activities. Antidepressants and LPA induced tyrosine phosphorylation of IGF-IR and insulin receptor-substrate-1 through LPA1 and Src. Prolonged exposure of CHO-K1 fibroblasts to either mianserin, mirtazapine or LPA enhanced cell proliferation as indicated by increased [(3)H]-thymidine incorporation and Ki-67 immunofluorescence. This effect was inhibited by blockade of LPA1- and ERK1/2 activity. These data provide evidence that different antidepressants induce LPA1 activation, leading to receptor tyrosine kinase transactivation, stimulation of ERK1/2 signaling and enhanced cell proliferation.

Antidepressant and neuroprotective effect of the Chinese herb kaixinsan against lentiviral shRNA knockdown brain-derived neurotrophic factor-induced injury in vitro and in vivo

Depression has been associated with reduced expression of brain-derived neurotrophic factor (BDNF) in the hippocampus. Previous studies have demonstrated that the herbal medicine formula, 'kaixinsan' (KXS), could ameliorate the severity of depression and increase cAMP response element-binding protein expression. There is direct evidence suggesting that the reduction of the BDNF protein in specific brain sites can provoke depressive-like behaviour or affect neurogenesis in vivo. However, the biological mechanisms between the antidepressant and neuroprotective effect of KXS and the alterations in BDNF levels in in vivo and in vitro models remain unclear. Using BDNF knockdown mediated by lentiviral vectors (LV-shBDNF-3) transfected with primary hippocampal neurons and following injection into the dentate gyrus of the hippocampus, it was demonstrated that a reduction in BDNF expression affects cell viability and animal behaviours associated with depression. During treatment with KXS after the lentiviral shRNA silencing of BDNF in cell and animal, cell viability, body weight, the sucrose preference test (SPT), the open field test (OFT) the Morris Water Maze (MWM) task and BDNF expression were measured. KXS attenuated LV-shBDNF-3-induced cell death in primary hippocampal neurons and also improved the sucrose intake in SPT, ambulatory response in OFT and learning ability in MWM against LV-shBDNF-3-induced depressive-like syndromes. Moreover, immunoblot analysis confirmed that KXS could reverse LV-shBDNF-induced BDNF reduction either in vitro or in vivo. These findings provide substantial evidence for supporting a neurotrophic hypothesis of depression and specify BDNF targets for potential antidepressant interventions. Moreover, the antagonism between LV-shRNA BDNF knockdown and KXS may depend on multiple compounds with synergistic mechanisms that modulate the different signal transduction networks directly or indirectly, increasing BDNF expression and exerting its neuroprotective and antidepressant-like effects.

Transcriptional dys-regulation in anxiety and major depression: 5-HT1A gene promoter architecture as a therapeutic opportunity

The etiology of major depression remains unclear, but reduced activity of the serotonin (5-HT) system remains implicated and treatments that increase 5-HT neurotransmission can ameliorate depressive symptoms. 5-HT1A receptors are critical regulators of the 5- HT system. They are expressed as both presynaptic autoreceptors that negatively regulate 5-HT neurons, and as post-synaptic heteroreceptors on non-serotonergic neurons in the hippocampus, cortex, and limbic system that are critical to mediate the antidepressant actions of 5-HT. Thus, 5-HT1A auto- and heteroreceptors have opposite actions on serotonergic neurotransmission. Because most 5-HT1A ligands target both auto- and heteroreceptors their efficacy has been limited, resulting in weak or unclear responses. We propose that by understanding the transcriptional regulation of the 5-HT1A receptor it may be possible to regulate its expression differentially in raphe and projection regions. Here we review the transcriptional architecture of the 5-HT1A gene (HTR1A) with a focus on specific DNA elements and transcription factors that have been shown to regulate 5-HT1A receptor expression in the brain. Association studies with the functional HTR1A promoter polymorphism rs6295 suggest a new model for the role of the 5-HT1A receptor in susceptibility to depression involving early deficits in cognitive, fear and stress reactivity as stressors that may ultimately lead to depression. We present evidence that by targeting specific transcription factors it may be possible to oppositely regulate 5-HT1A auto- and heteroreceptor expression, synergistically increasing serotonergic neurotransmission for the treatment of depression.

Valproic acid protects neurons and promotes neuronal regeneration after brachial plexus avulsion

Valproic acid has been shown to exert neuroprotective effects and promote neurite outgrowth in several peripheral nerve injury models. However, whether valproic acid can exert its beneficial effect on neurons after brachial plexus avulsion injury is currently unknown. In this study, brachial plexus root avulsion models, established in Wistar rats, were administered daily with valproic acid dissolved in drinking water (300 mg/kg) or normal water. On days 1, 2, 3, 7, 14 and 28 after avulsion injury, tissues of the C5-T1 spinal cord segments of the avulsion injured side were harvested to investigate the expression of Bcl-2, c-Jun and growth associated protein 43 by real-time PCR and western blot assay. Results showed that valproic acid significantly increased the expression of Bcl-2 and growth associated protein 43, and reduced the c-Jun expression after brachial plexus avulsion. Our findings indicate that valproic acid can protect neurons in the spinal cord and enhance neuronal regeneration following brachial plexus root avulsion.

Elevated levels of plasma brain derived neurotrophic factor in rapid cycling bipolar disorder patients

Impaired neuroplasticity may be implicated in the pathophysiology of bipolar disorder, involving peripheral alterations of the neurotrophins brain derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3). Evidence is limited by methodological issues and is based primarily on case-control designs. The aim of this study was to investigate whether BDNF and NT-3 levels differ between patients with rapid cycling bipolar disorder and healthy control subjects and whether BDNF and NT-3 levels alter with affective states in rapid cycling bipolar disorder patients. Plasma levels of BDNF and NT-3 were measured in 37 rapid cycling bipolar disorder patients and in 40 age- and gender matched healthy control subjects using enzyme-linked immunosorbent assay (ELISA). In a longitudinal design, repeated measurements of BDNF and NT-3 were evaluated in various affective states in bipolar disorder patients during a 6-12 months period and compared with repeated measurements in healthy control subjects. Careful attention was given to standardization of all procedures and adjustment for potential confounders of BDNF and NT-3. In linear mixed models, adjusting for demographical and lifestyle factors, levels of BDNF were significantly elevated in bipolar disorder patients in euthymic- (p<0.05), depressed- (p<0.005) and manic/hypomanic (p<0.005) states compared with healthy control subjects. Within bipolar disorder patients, adjusting for medication, there was no significant difference in BDNF levels between affective states, with equally elevated levels present in euthymic-, depressive- and manic/hypomanic patients. Levels of BDNF were higher in patients with longer duration of illness compared with patients with shorter duration of illness. We found no difference in NT-3 levels between bipolar disorder patients in any affective state compared with healthy control subjects and no difference in NT-3 levels between affective states in bipolar disorder patients. The results suggest that BDNF may be a marker related to illness stage in bipolar disorder, not varying with affective states in rapid cycling bipolar disorder patients. Due to the nature of comparison, it cannot be excluded that the finding of elevated BDNF levels in bipolar disorder patients compared with healthy controls could be influenced by medication.

Emotional consequences of neuropathic pain: insight from preclinical studies

Mood disorders such as depression and anxiety are frequently observed in patients suffering from chronic pain, including neuropathic pain. While this comorbidity is clinically well established, the underlying mechanism(s) remained unclear. The recent development of animal models now allows addressing the consequences of neuropathic pain. In this review, we report the preclinical evidences from anatomical, neuroimaging, behavioral, pharmacological and biochemical studies that address the anxiodepressive consequences of neuropathic pain. We present an overview of rodent models of these consequences and we discuss the challenges and parameters to consider for generating these models. We then discuss the possible mechanism(s) underlying anxiodepressive consequences by describing morphological and functional changes. Information is provided concerning neuroanatomical changes and plasticity, including LTP and LTD, in the anterior cingulate cortex, the insula, the hippocampus, the amygdala and the mesolimbic system, neuroendocrine parameters concerning the hypothalamo-pituitary-adrenal axis, neuroimmune response including the role of glial cells and cytokines, monoamine systems and changes in locus coeruleus noradrenergic system, and neurotrophic factors such as BDNF.

The neurobiology of bipolar disorder: identifying targets for specific agents and synergies for combination treatment

Bipolar disorder (BD) is a chronic psychiatric illness described by severe changes in mood. Extensive research has been carried out to understand the aetiology and pathophysiology of BD. Several hypotheses have been postulated, including alteration in genetic factors, protein expression, calcium signalling, neuropathological alteration, mitochondrial dysfunction and oxidative stress in BD. In the following paper, we will attempt to integrate these data in a manner which is to understand targets of treatment and how they may be, in particular, relevant to combination treatment. In summary, the data suggested that BD might be associated with neuronal and glial cellular impairment in specific brain areas, including the prefrontal cortex. From molecular and genetics: (1) alterations in dopaminergic system, through catechol-O-aminotransferase; (2) decreased expression and polymorphism on brain-derived neurotrophic factor; (3) alterations cyclic-AMP responsive element binding; (4) dysregulation of calcium signalling, including genome-wide finding for voltage-dependent calcium channel α-1 subunit are relevant findings in BD. Future studies are now necessary to understand how these molecular pathways interact and their connection to the complex clinical manifestations observed in BD.

Chronic treatment with mood-stabilizers attenuates abnormal hyperlocomotion of GluA1-subunit deficient mice

Abnormal excitatory glutamate neurotransmission and plasticity have been implicated in schizophrenia and affective disorders. Gria1−/− mice lacking GluA1 subunit (encoded by Gria1 gene) of AMPA-type glutamate receptor show robust novelty-induced hyperactivity, social deficits and heightened approach features, suggesting that they could be used to test for anti-manic activity of drugs. Here, we tested the efficacy of chronic treatment with established anti-manic drugs on behavioural properties of the Gria1−/− mice. The mice received standard mood stabilizers (lithium and valproate) and novel ones (topiramate and lamotrigine, used more as anticonvulsants) as supplements in rodent chow for at least 4 weeks. All drugs attenuated novelty-induced locomotor hyperactivity of the Gria1−/− mice, especially by promoting the habituation, while none of them attenuated 2-mg/kg amphetamine-induced hyperactivity as compared to control diet. Treatment with lithium and valproate reversed the elevated exploratory activity of Gria1−/− mice. Valproate treatment also reduced struggling behaviour in tail suspension test and restored reciprocally-initiated social contacts of Gria1−/− mice to the level shown by the wild-type Gria1+/+ mice. Gria1−/− mice consumed slightly more sucrose during intermittent sucrose exposure than the wild-types, but ran similar distances on running wheels. These behaviours were not consistently affected by lithium and valproate in the Gria1−/− mice. The efficacy of various anti-manic drug treatments on novelty-induced hyperactivity suggests that the Gria1−/− mouse line can be utilized in screening for new therapeutics.

Valproic acid selectively suppresses the formation of inhibitory synapses in cultured cortical neurons

Valproic acid (VPA) has been used to treat epileptic patients because of its ability to potentiate GABA signaling in the brain. Despite its clinical significance, VPA administration during pregnancy increases the risk of congenital abnormalities, such as neural tube defects and neurodevelopmental disorders including autism. Furthermore, recent studies revealed that early postnatal administration of VPA also leads to neurodevelopmental deficits in rodents. Here, using cultured cortical neurons derived from postnatal day 1 rats, we examined whether exposure to VPA would affect synapse formation. When neurons were exposed to 1mM VPA during early development, expression of the vesicular GABA transporter (VGAT) was selectively reduced, whereas other synaptic markers, including the vesicular glutamate transporters 1 and 2 (VGLUT1 and 2), were not affected. This VPA effect was mediated through inhibition of histone deacetylases (HDACs), since the effects were mostly recapitulated by an HDAC inhibitor, trichostatin A, but not by a VPA derivative, valpromide, which lacks HDAC inhibitor activity. Immunocytochemical analysis demonstrated that VPA exposure resulted in a retardation of axonal growth specific to GABAergic neurons and a decrease in VGAT-positive synapses. Since disturbance of the excitatory and inhibitory (E-I) balance has been implicated as a potential cause of multiple psychiatric disorders, our results may account for one of the cellular mechanisms underlying the pathogenesis of VPA-induced neurodevelopmental impairments.

Antidepressant-like effect of ascorbic acid is associated with the modulation of mammalian target of rapamycin pathway

The present study investigated the involvement of the PI3K, GSK-3β, heme oxygenase-1 (HO-1) and mTOR in the antidepressant-like effect of ascorbic acid in the tail suspension test (TST). Male Swiss mice were pretreated with ascorbic acid (1 mg/kg, p.o.) or vehicle and 45 min after, LY294002 (10 μg/site, i.c.v., reversible PI3K inhibitor), rapamycin (0.2 nmol/site, i.c.v., selective mTOR inhibitor), zinc protoporphyrin (ZnPP - 10 ng/site, i.c.v., HO-1 inhibitor) or vehicle was administered. We also investigated the synergistic effect of ascorbic acid (0.1 mg/kg, p.o., sub-effective dose in the TST) with lithium chloride (10 mg/kg, p.o., non-selective GSK-3β inhibitor), AR-A014418 (0.01 μg/site, i.c.v., selective GSK-3β inhibitor) or cobalt protoporphyrin (CoPP - 0.01 μg/site, i.c.v., HO-1 inducer) in the TST. The antidepressant-like effect of ascorbic acid (1 mg/kg, p.o.) was prevented by the treatment of mice with LY294002, rapamycin or ZnPP. In addition, sub-effective doses of lithium chloride, AR-A014418 or CoPP, combined with a sub-effective dose of ascorbic acid produced a synergistic antidepressant-like effect. We also demonstrated that 1 h after its administration, ascorbic acid increased the phosphorylation of p70S6K and the immunocontent of PSD-95 in the hippocampus of mice. These results indicate that the antidepressant-like effect of ascorbic acid in the TST might be dependent on the activation of PI3K and mTOR, inhibition of GSK-3β as well as induction of HO-1, reinforcing the notion that these are important targets for antidepressant activity and contributing to better elucidate the mechanisms underlying the antidepressant-like effect of ascorbic acid.

Glial abnormalities in mood disorders

Multiple lines of evidence indicate that mood disorders are associated with abnormalities in the brain's cellular composition, especially in glial cells. Considered inert support cells in the past, glial cells are now known to be important for brain function. Treatments for mood disorders enhance glial cell proliferation, and experimental stimulation of cell growth has antidepressant effects in animal models of mood disorders. These findings suggest that the proliferation and survival of glial cells may be important in the pathogenesis of mood disorders and may be possible targets for the development of new treatments. In this article we review the evidence for glial abnormalities in mood disorders, and we discuss glial cell biology and evidence from postmortem studies of mood disorders. The goal is not to carry out a comprehensive review but to selectively discuss existing evidence in support of an argument for the role of glial cells in mood disorders.

Moonlighting proteins and protein-protein interactions as neurotherapeutic targets in the G protein-coupled receptor field

There is serious interest in understanding the dynamics of the receptor-receptor and receptor-protein interactions in space and time and their integration in GPCR heteroreceptor complexes of the CNS. Moonlighting proteins are special multifunctional proteins because they perform multiple autonomous, often unrelated, functions without partitioning into different protein domains. Moonlighting through receptor oligomerization can be operationally defined as an allosteric receptor-receptor interaction, which leads to novel functions of at least one receptor protomer. GPCR-mediated signaling is a more complicated process than previously described as every GPCR and GPCR heteroreceptor complex requires a set of G protein interacting proteins, which interacts with the receptor in an orchestrated spatio-temporal fashion. GPCR heteroreceptor complexes with allosteric receptor-receptor interactions operating through the receptor interface have become major integrative centers at the molecular level and their receptor protomers act as moonlighting proteins. The GPCR heteroreceptor complexes in the CNS have become exciting new targets for neurotherapeutics in Parkinson's disease, schizophrenia, drug addiction, and anxiety and depression opening a new field in neuropsychopharmacology.