Prolonged Periods of Social Isolation From Weaning Reduce the Anti-inflammatory Cytokine IL-10 in Blood and Brain

Life stressors during critical periods are reported to trigger an immune dysfunction characterised by abnormal production of inflammatory cytokines. Despite the relationship between early stressors and schizophrenia is described, the evidence on inflammatory biomarkers remains limited. We aimed to investigate whether an imbalance between pro- and anti-inflammatory cytokines in the brain is reflected in the peripheral blood of rats submitted to post-weaning social isolation (pwSI), a model with validity to study schizophrenia. We evaluated pro- and anti-inflammatory cytokines (IL-6, TNF-α, and IL-10) simultaneously at blood, prefrontal cortex and hippocampal tissues (Milliplex MAP), including the respective cytokines gene expression (mRNA) (qRT-PCR TaqMan mastermix). We also performed a correlation matrix to explore significant correlations among cytokines (protein and mRNA) in blood and brain, as well as cytokines and total number of square crossings in the open field for isolated-reared animals. Male Wistar rats (n = 10/group) were kept isolated (n = 1/cage) or grouped (n = 3–4/cage) since weaning for 10 weeks. After this period, rats were assessed for locomotion and sacrificed for blood and brain cytokines measurements. Prolonged pwSI decreased IL-10 protein and mRNA in the blood, and IL-10 protein in the hippocampus, along with decreased IL-6 and its mRNA expression in the prefrontal cortex. Our results also showed that cytokines tend to correlate to one-another among the compartments investigated, although blood and brain correlations are far from perfect. IL-10 hippocampal levels were negatively correlated with hyperlocomotion in the open field. Despite the unexpected decrease in IL-6 and unchanged TNF-α levels contrast to the expected pro-inflammatory phenotype, this may suggest that reduced anti-inflammatory signalling may be critical for eliciting abnormal behaviour in adulthood. Altogether, these results suggest that prolonged early-life adverse events reduce the ability to build proper anti-inflammatory cytokine that is translated from blood-to-brain

Plasma prevalence of anti-N-methyl-d-aspartate receptor IgG antibodies in early stages of psychosis.

We investigated the feasibility of including plasma anti-NMDAR antibody screening in the assessment of first-episode psychosis patients in an early intervention programme in the Southern hemisphere. Anti-NMDAR IgG antibodies were assessed by ELISA in 166 patients (64.0% men), 166 matched population-based controls and 76 patients' siblings (30.3% men). Fisher's exact test and ANOVA were performed. Positive anti-NMDAR antibody patients were more often observed in bipolar disorder (10.0%) than schizophrenia (2.4%) or psychotic depression (3.1%), although no significant differences were observed. Our results are not conclusive regarding the inclusion of plasma anti-NMDAR IgG antibodies in differential diagnostic protocols for psychosis

Epigenetic-mediated N -methyl-D-aspartate receptor changes in the brain of isolated reared rats

Aim: We investigated: Grin1, Grin2a, Grin2b DNA methylation; NR1 and NR2 mRNA/protein in the prefrontal cortex (PFC); and hippocampus of male Wistar rats exposed to isolation rearing. Materials & methods: Animals were kept isolated or grouped (n = 10/group) from weaning for 10 weeks. Tissues were dissected for RNA/DNA extraction and N-methyl-D-aspartate receptor subunits were analyzed using quantitative reverse transcription (RT)-PCR, ELISA and pyrosequencing. Results: Isolated-reared animals had: decreased mRNA in PFC for all markers, increased NR1 protein in hippocampus and hypermethylation of Grin1 in PFC and Grin2b in hippocampus, compared with grouped rats. Associations between mRNA/protein and DNA methylation were found for both brain areas. Conclusion: This study indicates that epigenetic DNA methylation may underlie N-methyl-D-aspartate receptor mRNA/protein expression alterations caused by isolation rearing

Lifetime cannabis use and childhood trauma associated with CNR1 genetic variants increase the risk of psychosis: findings from the STREAM study

Objectives: Gene-environment interactions increase the risk of psychosis. The objective of this study was to investigate gene-gene and gene-environment interactions in psychosis, including single nucleotide variants (SNVs) of dopamine-2 receptor (D2R), N-methyl-d-aspartate receptor (NMDAR), and cannabinoid receptor type 1 (CB1R), lifetime cannabis use, and childhood trauma. Methods: Twenty-three SNVs of genes encoding D2R (DRD2: rs1799978, rs7131056, rs6275), NMDAR (GRIN1: rs4880213, rs11146020; GRIN2A: rs1420040, rs11866328; GRIN2B: rs890, rs2098469, rs7298664), and CB1R (CNR1: rs806380, rs806379, rs1049353, rs6454674, rs1535255, rs2023239, rs12720071, rs6928499, rs806374, rs7766029, rs806378, rs10485170, rs9450898) were genotyped in 143 first-episode psychosis patients (FEPp) and 286 communitybased controls by Illumina HumanCoreExome-24 BeadChip. Gene-gene and gene-environment associations were assessed using nonparametric Multifactor Dimensionality Reduction software. Results: Single-locus analyses among the 23 SNVs for psychosis and gene-gene interactions were not significant (p 4 0.05 for all comparisons); however, both environmental risk factors showed an association with psychosis (p o 0.001). Moreover, gene-environment interactions were significant for an SNV in CNR1 and cannabis use. The best-performing model was the combination of CNR1 rs12720071 and lifetime cannabis use (p o 0.001), suggesting an increased risk of psychosis. Conclusion: Our study supports the hypothesis of gene-environment interactions for psychosis involving T-allele carriers of CNR1 SNVs, childhood trauma, and cannabis use

Study of the expression of GluR1 and GluR2 in hippocampus of rats after injury by NMDA and evaluation of the neuroprotective effect of Parawixina 10.

Tem sido demonstrado o envolvimento do glutamato, através de diferentes receptores, nos mecanismos excitotóxicos que levam à morte neuronal na maioria das doenças neurodegenerativas do Sistema Nervoso Central (SNC). Adicionalmente, a Parawixina 10 (Pwx 10) tem sido demonstrada possuir efeito neuroprotetor em modelos de lesão atuando sobre o transporte de glutamato. Os objetivos gerais deste trabalho foram: i) estudar, em um curso temporal (24h, 1, 2 e 4 semanas), as alterações na expressão dos receptores AMPA no hipocampo de ratos induzidas pela injeção local de NMDA e ii) estudar o efeito neuroprotetor da Pwx 10 neste modelo. Foram utilizados ratos Wistar machos, submetidos à cirurgia estereotáxica para a microinjeção de salina ou NMDA no hipocampo dorsal. Alguns grupos de animais foram tratados com Pwx 10 a partir de 1h ou 24h após NMDA. O teste comportamental no labirinto aquático de Morris (LAM) e a coloração de Nissl foram realizados para verificar a extensão e eficácia da lesão por NMDA e o efeito neuroprotetor da Pwx 10. A expressão dos receptores foi estudada através do método de imunoistoquímica. Foram também realizados experimentos de imunofluorescência para GFAP e NeuN para avaliação da gliose e presença de neurônios na área lesada. Foi observado comprometimento das funções de aprendizado e memória no LAM, além de intensa perda de células neuronais e proliferação glial na região do CA1 que recebeu o NMDA, comprovando a eficiência da lesão pelo agonista. Observamos um curso temporal de diferentes alterações na expressão das subunidades GluR1 e GluR2 dos receptors AMPA no hipocampo, que podem ser relacionadas ao complexo mecanismo que ocorre em resposta à microinjeção de NMDA resultando em uma lesão local e na ativação da plasticidade neuronal. O tratamento com Pwx 10 apresentou efeito neuroprotetor, sendo este mais pronunciado quando a toxina foi administrada a partir de 1h após o agonista.It has been shown the involvement of glutamate, through different receptors, on the excitotoxic mechanisms which result on the neuronal death reported in most neurodegenerative disorders of the CNS. In addition, Parawixina 10 (Pwx 10) has been demonstrated to act as neuroprotective in models of injury regulating the glutamatergic neurotransmission through glutamate transporters. The aims of this work were: i) to study, in a time course (24h, 1, 2 and 4 weeks), the changes on the expression of AMPA receptors in rat hippocampus induced by NMDA intrahippocampal injection, and ii) to study the neuroprotective effect of Pwx 10 in this moldel. Male Wistar rats has been used, submitted to stereotaxic surgery for saline or NMDA microinjection into dorsal hippocampus. Some groups of animals were treated with Pwx 10 from 1h or 24h after NMDA. The behavioral test on Morris water maze (MWM) and the Nissl staining were performed for evaluating the extension and efficacy of the NMDA injury and the neuroprotective effect of the Pwx 10 . The expression of the receptors was analyzed by immunohistochemistry. The expression of GFAP and NeuN on the lesioned area has also been investigated by immunofluorescency. It was observed the impaiment of learning and memory functions in the MWM, and intense loss of neuronal cells and glial proliferation in CA1 that received the NMDA, confirming the efficiency of the injury by the agonist. We observed a time course of distinct changes on the expression of GluR1 and GluR2 subunits of AMPA receptors in hippocampus, which may be related to the complex mechanism triggered in response to NMDA injection resulting in a local injury and on the activation of neuronal plasticity. The treatment with Pwx 10 showed neuroprotective effect, being most pronounced when the toxin was administrated from 1h after NMDA

Differential expression of AMPA subunits induced by NMDA intrahippocampal injection in rats

Glutamate is involved in excitotoxic mechanisms by interacting with different receptors. Such interactions result in neuronal death associated with several neurodegenerative disorders of the central nervous system (CNS). The aim of this work was to study the time course of changes in the expression of GluR1 and GluR2 subunits of glutamate amino-acid-3-hydroxy-5-methyl-isoxazol-4-propionic acid (AMPA) receptors in rat hippocampus induced by NMDA intrahippocampal injection. Rats were submitted to stereotaxic surgery for NMDA or saline (control) microinjection into dorsal hippocampus and the parameters were evaluated 24 hours, 1, 2 and 4 weeks after injection. The extension and efficacy of the NMDA-induced injury were evaluated by Morris water maze (MWM) behavioral test and Nissl staining. The expression of GluR1 and GluR2 receptors, glial fibrillary acidic protein (GFAP) and neuronal marker (NeuN) was analyzed by immunohistochemistry. It was observed the impairment of learning and memory functions, loss of neuronal cells and glial proliferation in CA1 area of NMDA compared with control groups, confirming the injury efficacy. In addition, NMDA injection induced distinct changes in GluR1 and GluR2 expression over the time. In conclusion, such changes may be related to the complex mechanism triggered in response to NMDA injection resulting in a local injury and in the activation of neuronal plasticity

Erysothrine, an alkaloid extracted from flowers of Erythrina mulungu Mart. ex Benth: Evaluating its anticonvulsant and anxiolytic potential

In this study, we isolated the alkaloid erysothrine from the hydroalcoholic extract of flowers from E. mulungu and screened for its anticonvulsant and anxiolytic actions based on neuroethological and neurochemical experiments. Our results showed that the administration of erysothrine inhibited seizures evoked by bicuculline, PTZ, NMDA and most remarkably, kainic acid. Also, erysothrine induced an increase in the number of entries but not in the time spent in the open arms of the EPM. However, we did not notice any alterations in the light-dark choice or in the open-field tests. In preliminary neurochemistry tests, we also showed that erysothrine (0.001-10 mu g/mL) did not alter the GABA or glutamate synaptossomal uptake and binding. Altogether, our results describe an alkaloid with anticonvulsant activity and mild anxiolytic activity that might be considered well tolerated as it does not alter the general behavior of the animals in the used doses. (C) 2012 Elsevier Inc. All rights reserved.Foundation for Research Support of the State of Sao Paulo for Scientific Research (FAPESP) [2008/52627-9, 2009/11357-1, 2010/05200-0]Foundation for Research Support of the State of Sao Paulo for Scientific Research (FAPESP)CNPqCNPq [307062/2007-4