Chronic Trazodone and Citalopram Treatments Increase Trophic Factor and Circadian Rhythm Gene Expression in Rat Brain Regions Relevant for Antidepressant Efficacy.

Trazodone is an efficacious atypical antidepressant acting both as an SSRI and a 5HT2A and 5HT2C antagonist. Antagonism to H1-histaminergic and alpha1-adrenergic receptors is responsible for a sleep-promoting action. We studied long-term gene expression modulations induced by chronic trazodone to investigate the molecular underpinning of trazodone efficacy. Rats received acute or chronic treatment with trazodone or citalopram. mRNA expression of growth factor and circadian rhythm genes was evaluated by qPCR in the prefrontal cortex (PFCx), hippocampus, Nucleus Accumbens (NAc), amygdala, and hypothalamus. CREB levels and phosphorylation state were evaluated using Western blotting. BDNF levels were significantly increased in PFCx and hippocampus by trazodone and in the NAc and hypothalamus by citalopram. Likewise, TrkB receptor levels augmented in the PFCx after trazodone and in the amygdala after citalopram. FGF-2 and FGFR2 levels were higher after trazodone in the PFCx. The CREB phosphorylation state was increased by chronic trazodone in the PFCx, hippocampus, and hypothalamus. Bmal1 and Per1 were increased by both antidepressants after acute and chronic treatments, while Per2 levels were specifically augmented by chronic trazodone in the PFCx and NAc, and by citalopram in the PFCx, amygdala, and NAc. These findings show that trazodone affects the expression of neurotrophic factors involved in antidepressant responses and alters circadian rhythm genes implicated in the pathophysiology of depression, thus shedding light on trazodone's molecular mechanism of action.

Altered mRNA Levels of Stress-Related Peptides in Mouse Hippocampus and Caudate-Putamen in Withdrawal after Long-Term Intermittent Exposure to Tobacco Smoke or Electronic Cigarette Vapour.

Nicotine addiction is a severe public health problem. The aim of this study was to investigate the alterations in key neurotransmissions after 60 days of withdrawal from seven weeks of intermittent cigarette smoke, e-cigarette vapours, or an e-cigarette vehicle. In the nicotine withdrawal groups, increased depressive and anxiety/obsessive-compulsive-like behaviours were demonstrated in the tail suspension, sucrose preference and marble burying tests. Cognitive impairments were detected in the spatial object recognition test. A significant increase in Corticotropin-releasing factor (Crf) and Crf1 mRNA levels was observed, specifically after cigarette withdrawal in the caudate-putamen nucleus (CPu). The nociceptin precursor levels were reduced by cigarette (80%) and e-cigarette (50%) withdrawal in the CPu. The delta opioid receptor showed a significant reduction in the hippocampus driven by the exposure to an e-cigarette solubilisation vehicle, while the mRNA levels doubled in the CPu of mice that had been exposed to e-cigarettes. Withdrawal after exposure to e-cigarette vapour induced a 35% Bdnf mRNA decrease in the hippocampus, whereas Bdnf was augmented by 118% by cigarette withdrawal in the CPu. This study shows that long-term withdrawal-induced affective and cognitive symptoms associated to lasting molecular alterations in peptidergic signalling may determine the impaired neuroplasticity in the hippocampal and striatal circuitry.

Persistent cognitive and affective alterations at late withdrawal stages after long-term intermittent exposure to tobacco smoke or electronic cigarette vapour: Behavioural changes and their neurochemical correlates.

Smoking cessation induces a withdrawal syndrome associated with anxiety, depression, and impaired neurocognitive functions, but much less is known about the withdrawal of e-cigarettes (e-CIG). We investigated in Balb/c mice the behavioural and neurochemical effects of withdrawal for up to 90 days after seven weeks' intermittent exposure to e-CIG vapour or cigarette smoke (CIG). The withdrawal of e-CIG and CIG induced early behavioural alterations such as spatial memory deficits (spatial object recognition task), increased anxiety (elevated plus maze test) and compulsive-like behaviour (marble burying test) that persisted for 60-90 days. Notably, attention-related (virtual object recognition task) and depression-like behaviours (tail suspension and sucrose preference tests) appeared only 15-30 days after withdrawal and persisted for as long as up to 90 days. At hippocampal level, the withdrawal-induced changes in the levels of AMPA receptor GluA1 and GluA2/3 subunits, PSD 95 protein, corticotropin-releasing factor (Crf) and Crf receptor 1 (CrfR1) mRNA were biphasic: AMPA receptor subunit and PSD95 protein levels initially remained unchanged and decreased after 60-90 days, whereas Crf/CrfR1 mRNA levels initially increased and then markedly decreased after 60 days. These late reductions correlated with the behavioural impairments, particularly the appearance of depression-like behaviours. Our findings show that major behavioural and neurochemical alterations persist or even first appear late after the withdrawal of chronic CIG smoke or e-CIG vapour exposure, and underline importance of conducting similar studies of humans, including e-CIG vapers.

Highly polygenic architecture of antidepressant treatment response: Comparative analysis of SSRI and NRI treatment in an animal model of depression.

Response to antidepressant (AD) treatment may be a more polygenic trait than previously hypothesized, with many genetic variants interacting in yet unclear ways. In this study we used methods that can automatically learn to detect patterns of statistical regularity from a sparsely distributed signal across hippocampal transcriptome measurements in a large-scale animal pharmacogenomic study to uncover genomic variations associated with AD. The study used four inbred mouse strains of both sexes, two drug treatments, and a control group (escitalopram, nortriptyline, and saline). Multi-class and binary classification using Machine Learning (ML) and regularization algorithms using iterative and univariate feature selection methods, including InfoGain, mRMR, ANOVA, and Chi Square, were used to uncover genomic markers associated with AD response. Relevant genes were selected based on Jaccard distance and carried forward for gene-network analysis. Linear association methods uncovered only one gene associated with drug treatment response. The implementation of ML algorithms, together with feature reduction methods, revealed a set of 204 genes associated with SSRI and 241 genes associated with NRI response. Although only 10% of genes overlapped across the two drugs, network analysis shows that both drugs modulated the CREB pathway, through different molecular mechanisms. Through careful implementation and optimisations, the algorithms detected a weak signal used to predict whether an animal was treated with nortriptyline (77%) or escitalopram (67%) on an independent testing set. The results from this study indicate that the molecular signature of AD treatment may include a much broader range of genomic markers than previously hypothesized, suggesting that response to medication may be as complex as the pathology. The search for biomarkers of antidepressant treatment response could therefore consider a higher number of genetic markers and their interactions. Through predominately different molecular targets and mechanisms of action, the two drugs modulate the same Creb1 pathway which plays a key role in neurotrophic responses and in inflammatory processes. © 2016 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc.

Opioid gene expression changes and post-translational histone modifications at promoter regions in the rat nucleus accumbens after acute and repeated 3,4-methylenedioxy-methamphetamine (MDMA) exposure.

The recreational drug of abuse 3,4-methylenedioxymethamphetamine (MDMA) has been shown to produce neurotoxic damage and long-lasting changes in several brain areas. In addition to the involvement of serotoninergic and dopaminergic systems, little information exists about the contribution of nociceptin/orphaninFQ (N/OFQ)-NOP and dynorphin (DYN)-KOP systems in neuronal adaptations evoked by MDMA. Here we investigated the behavioral and molecular effects induced by acute (8mg/kg) or repeated (8mg/kg twice daily for seven days) MDMA exposure. MDMA exposure affected body weight gain and induced hyperlocomotion; this latter effect progressively decreased after repeated administration. Gene expression analysis indicated a down-regulation of the N/OFQ system and an up-regulation of the DYN system in the nucleus accumbens (NAc), highlighting an opposite systems regulation in response to MDMA exposure. Since histone modifications have been strongly associated to the addiction-related maladaptive changes, we examined two permissive (acH3K9 and me3H3K4) and two repressive transcription marks (me3H3K27 and me2H3K9) at the pertinent opioid gene promoter regions. Chromatin immunoprecipitation assays revealed that acute MDMA increased me3H3K4 at the pN/OFQ, pDYN and NOP promoters. Following acute and repeated treatment a significant decrease of acH3K9 at the pN/OFQ promoter was observed, which correlated with gene expression results. Acute treatment caused an acH3K9 increase and a me2H3K9 decrease at the pDYN promoter which matched its mRNA up-regulation. Our data indicate that the activation of the DYNergic stress system together with the inactivation of the N/OFQergic anti-stress system contribute to the neuroadaptive actions of MDMA and offer novel epigenetic information associated with MDMA abuse.

The endogenous and reactive depression subtypes revisited: integrative animal and human studies implicate multiple distinct molecular mechanisms underlying major depressive disorder.

BACKGROUND: Traditional diagnoses of major depressive disorder (MDD) suggested that the presence or absence of stress prior to onset results in either 'reactive' or 'endogenous' subtypes of the disorder, respectively. Several lines of research suggest that the biological underpinnings of 'reactive' or 'endogenous' subtypes may also differ, resulting in differential response to treatment. We investigated this hypothesis by comparing the gene-expression profiles of three animal models of 'reactive' and 'endogenous' depression. We then translated these findings to clinical samples using a human post-mortem mRNA study. METHODS: Affymetrix mouse whole-genome oligonucleotide arrays were used to measure gene expression from hippocampal tissues of 144 mice from the Genome-based Therapeutic Drugs for Depression (GENDEP) project. The study used four inbred mouse strains and two depressogenic 'stress' protocols (maternal separation and Unpredictable Chronic Mild Stress) to model 'reactive' depression. Stress-related mRNA differences in mouse were compared with a parallel mRNA study using Flinders Sensitive and Resistant rat lines as a model of 'endogenous' depression. Convergent genes differentially expressed across the animal studies were used to inform candidate gene selection in a human mRNA post-mortem case control study from the Stanley Brain Consortium. RESULTS: In the mouse 'reactive' model, the expression of 350 genes changed in response to early stresses and 370 in response to late stresses. A minimal genetic overlap (less than 8.8%) was detected in response to both stress protocols, but 30% of these genes (21) were also differentially regulated in the 'endogenous' rat study. This overlap is significantly greater than expected by chance. The VAMP-2 gene, differentially expressed across the rodent studies, was also significantly altered in the human study after correcting for multiple testing. CONCLUSIONS: Our results suggest that 'endogenous' and 'reactive' subtypes of depression are associated with largely distinct changes in gene-expression. However, they also suggest that the molecular signature of 'reactive' depression caused by early stressors differs considerably from that of 'reactive' depression caused by late stressors. A small set of genes was consistently dysregulated across each paradigm and in post-mortem brain tissue of depressed patients suggesting a final common pathway to the disorder. These genes included the VAMP-2 gene, which has previously been associated with Axis-I disorders including MDD, bipolar depression, schizophrenia and with antidepressant treatment response. We also discuss the implications of our findings for disease classification, personalized medicine and case-control studies of MDD.

Single-cell-led drug repurposing for Alzheimer's disease.

Alzheimer's disease is the most common form of dementia. Notwithstanding the huge investments in drug development, only one disease-modifying treatment has been recently approved. Here we present a single-cell-led systems biology pipeline for the identification of drug repurposing candidates. Using single-cell RNA sequencing data of brain tissues from patients with Alzheimer's disease, genome-wide association study results, and multiple gene annotation resources, we built a multi-cellular Alzheimer's disease molecular network that we leveraged for gaining cell-specific insights into Alzheimer's disease pathophysiology and for the identification of drug repurposing candidates. Our computational approach pointed out 54 candidate drugs, mainly targeting MAPK and IGF1R signaling pathways, which could be further evaluated for their potential as Alzheimer's disease therapy.

Increased Expression of Autophagy-Related Genes in Alzheimer's Disease-Type 2 Diabetes Mellitus Comorbidity Models in Cells.

The association between Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM) has been extensively demonstrated, but despite this, the pathophysiological mechanisms underlying it are still unknown. In previous work, we discovered a central role for the autophagy pathway in the common alterations observed between AD and T2DM. In this study, we further investigate the role of genes belonging to this pathway, measuring their mRNA expression and protein levels in 3xTg-AD transgenic mice, an animal model of AD. Moreover, primary mouse cortical neurons derived from this model and the human H4Swe cell line were used as cellular models of insulin resistance in AD brains. Hippocampal mRNA expression showed significantly different levels for Atg16L1, Atg16L2, GabarapL1, GabarapL2, and Sqstm1 genes at different ages of 3xTg-AD mice. Significantly elevated expression of Atg16L1, Atg16L2, and GabarapL1 was also observed in H4Swe cell cultures, in the presence of insulin resistance. Gene expression analysis confirmed that Atg16L1 was significantly increased in cultures from transgenic mice when insulin resistance was induced. Taken together, these results emphasise the association of the autophagy pathway in AD-T2DM co-morbidity, providing new evidence about the pathophysiology of both diseases and their mutual interaction.

The Role of IgLON Cell Adhesion Molecules in Neurodegenerative Diseases.

In the brain, cell adhesion molecules (CAMs) are critical for neurite outgrowth, axonal fasciculation, neuronal survival and migration, and synapse formation and maintenance. Among CAMs, the IgLON family comprises five members: Opioid Binding Protein/Cell Adhesion Molecule Like (OPCML or OBCAM), Limbic System Associated Membrane Protein (LSAMP), neurotrimin (NTM), Neuronal Growth Regulator 1 (NEGR1), and IgLON5. IgLONs exhibit three N-terminal C2 immunoglobulin domains; several glycosylation sites; and a glycosylphosphatidylinositol anchoring to the membrane. Interactions as homo- or heterodimers in cis and in trans, as well as binding to other molecules, appear critical for their functions. Shedding by metalloproteases generates soluble factors interacting with cellular receptors and activating signal transduction. The aim of this review was to analyse the available data implicating a role for IgLONs in neuropsychiatric disorders. Starting from the identification of a pathological role for antibodies against IgLON5 in an autoimmune neurodegenerative disease with a poorly understood mechanism of action, accumulating evidence links IgLONs to neuropsychiatric disorders, albeit with still undefined mechanisms which will require future thorough investigations.

Protein Networks Associated with Native Metabotropic Glutamate 1 Receptors (mGlu1) in the Mouse Cerebellum.

The metabotropic glutamate receptor 1 (mGlu1) plays a pivotal role in synaptic transmission and neuronal plasticity. Despite the fact that several interacting proteins involved in the mGlu1 subcellular trafficking and intracellular transduction mechanisms have been identified, the protein network associated with this receptor in specific brain areas remains largely unknown. To identify novel mGlu1-associated protein complexes in the mouse cerebellum, we used an unbiased tissue-specific proteomic approach, namely co-immunoprecipitation followed by liquid chromatography/tandem mass spectrometry analysis. Many well-known protein complexes as well as novel interactors were identified, including G-proteins, Homer, δ2 glutamate receptor, 14-3-3 proteins, and Na/K-ATPases. A novel putative interactor, KCTD12, was further investigated. Reverse co-immunoprecipitation with anti-KCTD12 antibodies revealed mGlu1 in wild-type but not in KCTD12-knock-out homogenates. Freeze-fracture replica immunogold labeling co-localization experiments showed that KCTD12 and mGlu1 are present in the same nanodomain in Purkinje cell spines, although at a distance that suggests that this interaction is mediated through interposed proteins. Consistently, mGlu1 could not be co-immunoprecipitated with KCTD12 from a recombinant mammalian cell line co-expressing the two proteins. The possibility that this interaction was mediated via GABAB receptors was excluded by showing that mGlu1 and KCTD12 still co-immunoprecipitated from GABAB receptor knock-out tissue. In conclusion, this study identifies tissue-specific mGlu1-associated protein clusters including KCTD12 at Purkinje cell synapses.

Slow dissociation of partial agonists from the D2 receptor is linked to reduced prolactin release.

In this study we investigated the correlation between affinity, efficacy, peripheral receptor occupancy, and kinetic properties of D2 dopamine receptor ligands with time-course evaluations of prolactin release in rat blood. We profiled typical and atypical antipsychotic antagonists at D2 receptors, the partial agonist aripiprazole, and four novel partial agonist compounds with different properties. Clozapine and quetiapine revealed lower prolactin release and fast dissociation kinetics, linking fast dissociation and prolactin-sparing properties. Surprisingly, haloperidol, a highly prolactin-releasing antagonist, shared intermediate dissociation properties. Factors other than kinetic properties may thus contribute to prolactin-releasing properties of antagonists. Partial agonists sharing similar efficacies and receptor occupancies differed markedly in their ability to induce hyperprolactinaemia. Aripiprazole moderately released prolactin even at high receptor occupancies, with slow dissociation from D2 receptors. Other compounds displaying low affinities and fast dissociations released prolactin substantially, although less than haloperidol. The effect augmented after repeated administrations. Compounds with high affinities and slow dissociation rates stimulated moderate prolactin release at high receptor occupancies, reaching a ceiling effect at 50-60% occupancy. Moreover, the effect developed tolerance. In conclusion, we investigated the affinity and kinetic properties of D2 partial agonists associated with their ability to induce prolactin release in blood. We propose that for D2 partial agonists, at comparable intrinsic activities and peripheral occupancies, the prolactin-releasing properties are linked to their kinetic rate properties. Differently from D2 antagonists, partial agonists display slow dissociation and high affinity associated with a low prolactin release profile.

Proteomics of rat hypothalamus, hippocampus and pre-frontal/frontal cortex after central administration of the neuropeptide PACAP.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide that exerts pleiotropic functions, acting as a hypophysiotropic factor, a neurotrophic and a neuroprotective agent. The molecular pathways activated by PACAP to exert its physiological roles in brain are incompletely understood. In this study, adrenocorticotropic hormone (ACTH), prolactin, luteinising hormone (LH), follicle-stimulating hormone (FSH), thyroid-stimulating hormone (TSH), brain-derived neurotrophic factor and corticosterone blood levels were determined before and 20, 40, 60, and 120 min after PACAP intracerebroventricular administration. PACAP treatment increased ACTH, corticosterone, LH and FSH blood concentrations, while it decreased TSH levels. A proteomics investigation was carried out in hypothalamus, hippocampus and pre-frontal/frontal cortex (P/FC) using 2-dimensional gel electrophoresis at 120 min, the end-point suggested by studies on PACAP hypophysiotropic activities. Spots showing statistically significant alterations after PACAP treatment were identified by Matrix-assisted laser desorption/ionization-Time of flight mass spectrometry. Identified proteins were consistent with PACAP involvement in different molecular processes in brain. Altered expression levels were observed for proteins involved in cytoskeleton modulation and synaptic plasticity: actin in the hypothalamus; stathmin, dynamin, profilin and cofilin in hippocampus; synapsin in P/FC. Proteins involved in cellular differentiation were also modulated: glutathione-S-transferase α and peroxiredoxin in hippocampus; nucleoside diphosphate kinase in P/FC. Alterations were detected in proteins involved in neuroprotection, neurodegeneration and apoptosis: ubiquitin carboxyl-terminal hydrolase isozyme L1 and heat shock protein 90-ß in hypothalamus; α-synuclein in hippocampus; glyceraldehyde-3-phosphate dehydrogenase and prohibitin in P/FC. This proteomics study identified new proteins involved in molecular mechanisms mediating PACAP functions in the central nervous system.

Neuropeptide Y, calcitonin gene-related peptide, and neurokinin A in brain regions of HAB rats correlate with anxiety-like behaviours.

Anxiety disorders are pervasive psychiatric disorders causing great suffering. The high (HAB) and low (LAB) anxiety-related behaviour rats were selectively bred to investigate neurobiological correlates of anxiety. We compared the level of neuropeptides relevant for anxiety- and depression-related behaviours in selected brain regions of HAB and LAB rats. Increased anxiety and depression-like behaviours of male and female HAB rats in the elevated plus-maze and forced swim tests were accompanied by elevated levels of neuropeptide Y (NPY) in the prefrontal (PFC), frontal (FC) and cingulate cortex (CCx), the striatum, and periaqueductal grey (PAG). Moreover, HAB rats displayed sex-dependent, elevated levels of calcitonin gene-related peptide (CGRP) in PFC, FC, CCx, hippocampus, and PAG. Higher neurokinin A (NKA) levels were detected in CCx, striatum, and PAG in HAB males and in CCx and hypothalamus in HAB females. Increased neurotensin was detected in CCx and PAG in HAB males and in hypothalamus in HAB females. Elevated corticotropin-releasing hormone (CRH) levels appeared in female HAB hypothalamus. Significant correlations were found between anxiety-like behaviour and NPY, CGRP, NKA, and neurotensin, particularly with NPY in CCx and striatum, CGRP in FC and hippocampus, and NKA in entorhinal cortex. This is the first report of NPY, CGRP, NKA, Neurotensin, and CRH measurements in brain regions of HAB and LAB rats, which showed widespread NPY and CGRP alterations in cortical regions, with NKA and neurotensin changes localised in sub-cortical areas. The results may contribute to elucidate pathophysiological mechanisms underlying anxiety and depression and should facilitate identifying novel therapeutic targets.

Escitalopram affects cytoskeleton and synaptic plasticity pathways in a rat gene-environment interaction model of depression as revealed by proteomics. Part II: environmental challenge.

Large-scale investigations aimed at elucidating the molecular mechanism of action of antidepressant treatment are achievable through the application of proteomic technologies. We performed a proteomic study on the Flinders Sensitive Line (FSL), a genetically selected rat model of depression, and the control Flinders Resistant Line (FRL). To evaluate gene-environment interactions, FSL and FRL animals were separated from their mothers for 3 h from postnatal days 2 to 14 (maternal separation; MS), since early-life trauma is considered an important antecedent of depression. All groups received either escitalopram (Esc) admixed to food pellets (25 mg/kg.d) or vehicle for 1 month. Protein extracts from prefrontal/frontal cortex and hippocampus were separated by 2D electrophoresis. Proteins differentially modulated were identified by mass spectrometry. Bioinformatics analyses were performed to discover gene ontology terms associated with the modulated proteins. This paper was focused on the modifications induced by the environmental challenge of MS, both on the predisposed genetic background and on the resistant phenotype. The combination between Esc treatment and MS was investigated by comparing the MS, Esc-treated rats with rats subjected to each single procedure. In MS rats, antidepressant treatment influenced mainly proteins involved in carbohydrate metabolism in FSL rats and in vesicle-mediated transport in FRL rats. When studying the interaction between Esc and MS vs. non-separated rats, proteins playing a role in cytoskeleton organization, neuronal development, vesicle-mediated transport and synaptic plasticity were identified. The results provide further support to the available reports that antidepressant treatment affects intracellular pathways and also suggest new potential targets for future therapeutic intervention.

Escitalopram modulates neuron-remodelling proteins in a rat gene-environment interaction model of depression as revealed by proteomics. Part I: genetic background.

The wide-scale analysis of protein expression provides a powerful strategy for the molecular exploration of complex pathophysiological mechanisms, such as the response to antidepressants. Using a 2D proteomic approach we investigated the Flinders Sensitive Line (FSL), a genetically selected rat model of depression, and the control Flinders Resistant Line (FRL). To evaluate gene-environment interactions, FSL and FRL pups were separated from their mothers for 3 h (maternal separation, MS), as early-life trauma is considered an important antecedent of depression. All groups were treated with either escitalopram (Esc) admixed to food (25 mg/kg.d) or vehicle for 1 month. At the week 3, forced swim tests were performed. Protein extracts from prefrontal/frontal cortex and hippocampus were separated by 2D electrophoresis. Proteins displaying statistically significant differences in expression levels were identified by mass spectrometry. Immobility time values in the forced swim test were higher in FSL rats and reduced by antidepressant treatment. Moreover, the Esc-induced reduction in immobility time was not detected in MS rats. The impact of genetic background in response to Esc was specifically investigated here. Bioinformatics analyses highlighted gene ontology terms showing tighter associations with the modulated proteins. Esc modulated protein belonging to cytoskeleton organization in FSL; carbohydrate metabolism and intracellular transport in FRL. Proteins differently modulated in the two strains after MS and Esc play a role in cytoskeleton organization, vesicle-mediated transport, apoptosis regulation and macromolecule catabolism. These findings suggest pathways involved in neuronal remodelling as molecular correlates of response to antidepressants in a model of vulnerability.

Folate metabolism biomarkers from two randomised placebo-controlled clinical studies with paroxetine and venlafaxine.

OBJECTIVES: Based on the hypothesis of a role for folate and vitamin B12 in major depressive disorders (MDD), we aimed at validating the association between folate pathway biomarkers and depression or antidepressant response in clinical trial populations. METHODS: We investigated serum levels erythrocyte folate and serum levels of homocysteine, vitamin B12, and folate as disease and response biomarkers for MDD in two independent randomised, placebo-controlled clinical trials, where paroxetine or venlafaxine were used as active controls, for a total of 881 patients. RESULTS: Significant but weak correlations between depression severity and biomarker levels could be detected in the paroxetine study for serum folate and vitamin B12, with no correlations for any biomarker in the venlafaxine study. Besides a weak association for erythrocyte folate in the venlafaxine study, no significant associations were observed between treatment response and pre-treatment levels of any of the biomarkers tested. CONCLUSIONS: Notwithstanding the relatively large number of patients tested, we did not find consistent associations between folate biomarkers and MDD severity, or response to paroxetine and venlafaxine. Our results may be related to the particular study design or clinical population; however, our findings do not support the hypothesis of a dysfunction of one-carbon metabolism in MDD.

An Exploratory Pilot Study of Changes in Global DNA Methylation in Patients Undergoing Major Breast Surgery Under Opioid-Based General Anesthesia.

This study aimed to investigate DNA methylation levels in patients undergoing major breast surgery under opioid-based general anesthesia. Blood samples were collected from eleven enrolled patients, before, during and after anesthesia. PBMC were isolated and global DNA methylation levels as well as DNA methyltransferase (DNMT) and cytokine gene expression were assessed. DNA methylation levels significantly declined by 26%, reversing the direction after the end of surgery. Likewise, DNMT1a mRNA expression was significantly reduced at all time points, with lowest level of -68%. DNMT3a and DNMT3b decreased by 65 and 71%, respectively. Inflammatory cytokines IL6 and TNFα mRNA levels showed a trend for increased expression at early time-points to end with a significant decrease at 48 h after surgery. This exploratory study revealed for the first time intraoperative global DNA hypomethylation in patients undergoing major breast surgery under general anesthesia with fentanyl. The alterations of global DNA methylation here observed seem to be in agreement with DNMTs gene expression changes. Furthermore, based on perioperative variations of IL6 and TNFα gene expression, we hypothesize that DNA hypomethylation may occur as a response to surgical stress rather than to opiate exposure.

Depression-Associated Gene Negr1-Fgfr2 Pathway Is Altered by Antidepressant Treatment.

The Negr1 gene has been significantly associated with major depression in genetic studies. Negr1 encodes for a cell adhesion molecule cleaved by the protease Adam10, thus activating Fgfr2 and promoting neuronal spine plasticity. We investigated whether antidepressants modulate the expression of genes belonging to Negr1-Fgfr2 pathway in Flinders sensitive line (FSL) rats, in a corticosterone-treated mouse model of depression, and in mouse primary neurons. Negr1 and Adam10 were the genes mostly affected by antidepressant treatment, and in opposite directions. Negr1 was down-regulated by escitalopram in the hypothalamus of FSL rats, by fluoxetine in the hippocampal dentate gyrus of corticosterone-treated mice, and by nortriptyline in hippocampal primary neurons. Adam10 mRNA was increased by nortriptyline administration in the hypothalamus, by escitalopram in the hippocampus of FSL rats, and by fluoxetine in mouse dorsal dentate gyrus. Similarly, nortriptyline increased Adam10 expression in hippocampal cultures. Fgfr2 expression was increased by nortriptyline in the hypothalamus of FSL rats and in hippocampal neurons. Lsamp, another IgLON family protein, increased in mouse dentate gyrus after fluoxetine treatment. These findings suggest that Negr1-Fgfr2 pathway plays a role in the modulation of synaptic plasticity induced by antidepressant treatment to promote therapeutic efficacy by rearranging connectivity in corticolimbic circuits impaired in depression.

Gene expression signature of antidepressant treatment response/non-response in Flinders Sensitive Line rats subjected to maternal separation.

Neurobiological underpinnings of treatment-resistant depression, a debilitating condition associated with significant functional impairment, have not been elucidated. Consequently, the aim of this study was to use animal models of response and resistance to antidepressant treatment, in an attempt to identify differences in associated transcriptional responses. Flinders Sensitive Line rats were subjected to maternal separation (MS) and chronically treated with Escitalopram or Nortriptyline. Antidepressants reduced immobility time in the forced swim test in non-MS rats, while lack of antidepressant behavioural response was observed in MS animals. We developed a novel bioinformatic algorithm that enabled identification of transcriptional signatures in hippocampus and pre-frontal cortex that discriminate vehicle- and antidepressant-treated subjects in both MS and non-MS rats. Functional annotation analysis showed that in antidepressant-responder rats the most enriched pathways included IQGAPs activation, toll-like receptor trafficking, energy metabolism, and regulation of endopeptidase activity. The analysis of interacting proteins implicated synaptic vesicles and neurotransmitter release, ubiquitin regulation, cytoskeleton organisation and carbohydrate metabolism. In contrast, in treatment-resistant MS rats, main expression changes were revealed in ribosomal proteins, inflammatory responses, transcriptional/epigenetic regulation, and small GTPases. Susceptibility signature shared Rtn1, Zdhhc5, Igsf6, and Sim1 genes with the latest depression GWAS meta-analysis, while antidepressant resistance signature shared Ctnnd1, Rbms3, Atp1a3, and Pla2r1 genes. In conclusion, this study demonstrated that distinct transcriptional signatures are associated with behavioural response or non-response to antidepressant treatment. The identification of genes involved in antidepressant response will increase the comprehension of the neurobiological underpinnings of treatment-resistant depression, thus contributing to identification of novel therapeutic targets.

Biomarkers for response in major depression: comparing paroxetine and venlafaxine from two randomised placebo-controlled clinical studies.

The identification of biomarkers of response might speed drug development and set the premises to assist clinical practice in psychiatry. In this work, we evaluated a panel of peripheral biomarkers (including IL-6, IL-10, TNF-α, TNFRII, BDNF, CRP, MMP9 and PAI1) in depressed patients receiving paroxetine, venlafaxine, or placebo. Samples were obtained from two randomised placebo-controlled studies evaluating the efficacy and tolerability of a novel drug candidate, using either paroxetine or venlafaxine as active comparators. In both studies, the biomarker candidates were analysed in plasma collected at randomization and after 10 weeks of treatment with either placebo or active comparator (for a total of 106 and 108 subjects in the paroxetine and venlafaxine study, respectively). Data were obtained by multiplexing sandwich-ELISA system. Data were subjected to statistical analysis to assess their correlation with baseline severity and with response outcome. Increases in biomarker levels were correlated with reduction in depression severity for TNF-α, IL-6 IL-10 and CRP. Response to paroxetine treatment correlated with baseline IL-10, IL-6 and TNF-α levels, with the strongest signal being observed in males. In the venlafaxine study, a correlation was observed only between CRP level at randomisation and response, suggesting differences between the two active treatments and the two studies. Our investigations suggest that a combination of pro- and anti-inflammatory cytokines may predict response outcome in patients treated with paroxetine. The potential for IL-10, IL-6 and TNF-α as response biomarkers for a wider range of antidepressants warrants further investigations in clinical trials with other monoamine reuptake inhibitors.