Viral infection, inflammation and schizophrenia

Induced Pluripotent Stem Cells Reveal Common Neurodevelopmental Genome Deprograming in Schizophrenia

Schizophrenia is a neurodevelopmental disorder characterized by complex aberrations in the structure, wiring, and chemistry of multiple neuronal systems. The abnormal developmental trajectory of the brain is established during gestation, long before clinical manifestation of the disease. Over 200 genes and even greater numbers of single nucleotide polymorphisms and copy number variations have been linked with schizophrenia. How does altered function of such a variety of genes lead to schizophrenia? We propose that the protein products of these altered genes converge on a common neurodevelopmental pathway responsible for the development of brain neural circuit and neurotransmitter systems. The results of a multichanneled investigation using induced pluripotent stem cell (iPSCs)- and embryonic stem cell (ESCs)-derived neuronal committed cells (NCCs) indicate an early (preneuronal) developmental-genomic etiology of schizophrenia and that the dysregulated developmental gene networks are common to genetically unrelated cases of schizophrenia. The results support a "watershed" mechanism in which mutations within diverse signaling pathways affect the common pan-ontogenic mechanism, integrative nuclear (n)FGFR1 signaling (INFS). Dysregulation of INFS in schizophrenia NCCs deconstructs coordinated gene networks and leads to formation of new networks by the dysregulated genes. This genome deprograming affects critical gene programs and pathways for neural development and functions. Studies show that the genomic deprograming reflect an altered nFGFR1-genome interactions and deregulation of miRNA genes by nFGFR1. In addition, changes in chromatin topology imposed by nFGFR1 may play a role in coordinate gene dysregulation in schizophrenia.

Brain Organoids: Expanding Our Understanding of Human Development and Disease

Stem cell-derived brain organoids replicate important stages of the prenatal human brain development and combined with the induced pluripotent stem cell (iPSC) technology offer an unprecedented model for investigating human neurological diseases including autism and microcephaly. We describe the history and birth of organoids and their application, focusing on cerebral organoids derived from embryonic stem cells and iPSCs. We discuss new insights into organoid-based model of schizophrenia and shed light on challenges and future applications of organoid-based disease model system. This review also suggests hitherto unrevealed potential applications of organoids in combining with new technologies such as nanophotonics/optogenomics for controlling brain development and atomic force microscopy for studying mechanical forces that shape the developing brain.

Maternal immune activation in neurodevelopmental disorders

Converging lines of evidence from basic science and clinical studies suggest a relationship between maternal immune activation (MIA) and neurodevelopmental disorders such as autism spectrum disorder (ASD) and schizophrenia. The mechanisms through which MIA increases the risk of neurodevelopmental disorders have become a subject of intensive research. This review aims to describe how dysregulation of microglial function and immune mechanisms may link MIA and neurodevelopmental pathologies. We also summarize the current evidence in animal models of MIA. Developmental Dynamics 247:588-619, 2018. © 2017 Wiley Periodicals, Inc.

Chorioamnionitis, IL-17A, and fetal origins of neurologic disease

The Centers for Disease Control and Prevention estimate that 1 in 323 infants have cerebral palsy. Highly correlated to intrauterine infection and inflammation, the incidence of cerebral palsy has remained constant over the last few decades despite significant advances in neonatal intensive care including improved ventilator techniques, surfactant therapy, maternal steroid administration, and use of intrapartum empiric antimicrobials. Recent advances in our understanding of immune responses to infection and inflammation have identified the cytokine IL-17A as a crucial component of early proinflammatory mediators that cause brain injury associated with neurologic impairment. Remarkably, maternal inflammatory responses to in utero inflammation and infection can also lead to potentially debilitating neurologic conditions in the offspring, which often become clinically apparent during childhood and/or early adulthood. This review details the role of IL-17A in fetal and maternal proinflammatory responses that lead to fetal brain injury and neurologic sequelae, including cerebral palsy. Recent findings regarding the role of maternal inflammatory responses in the development of childhood and adult neurologic conditions, such as autism, schizophrenia, and multiple sclerosis, will also be highlighted.

Cerebral organoids reveal early cortical maldevelopment in schizophrenia-computational anatomy and genomics, role of FGFR1

Studies of induced pluripotent stem cells (iPSCs) from schizophrenia patients and control individuals revealed that the disorder is programmed at the preneuronal stage, involves a common dysregulated mRNA transcriptome, and identified Integrative Nuclear FGFR1 Signaling a common dysregulated mechanism. We used human embryonic stem cell (hESC) and iPSC-derived cerebral organoids from four controls and three schizophrenia patients to model the first trimester of in utero brain development. The schizophrenia organoids revealed an abnormal scattering of proliferating Ki67+ neural progenitor cells (NPCs) from the ventricular zone (VZ), throughout the intermediate (IZ) and cortical (CZ) zones. TBR1 pioneer neurons and reelin, which guides cortico-petal migration, were restricted from the schizophrenia cortex. The maturing neurons were abundantly developed in the subcortical regions, but were depleted from the schizophrenia cortex. The decreased intracortical connectivity was denoted by changes in the orientation and morphology of calretinin interneurons. In schizophrenia organoids, nuclear (n)FGFR1 was abundantly expressed by developing subcortical cells, but was depleted from the neuronal committed cells (NCCs) of the CZ. Transfection of dominant negative and constitutively active nFGFR1 caused widespread disruption of the neuro-ontogenic gene networks in hESC-derived NPCs and NCCs. The fgfr1 gene was the most prominent FGFR gene expressed in NPCs and NCCs, and blocking with PD173074 reproduced both the loss of nFGFR1 and cortical neuronal maturation in hESC cerebral organoids. We report for the first time, progression of the cortical malformation in schizophrenia and link it to altered FGFR1 signaling. Targeting INFS may offer a preventive treatment of schizophrenia.

The association between season of birth, age at onset, and clozapine use in schizophrenia

OBJECTIVE

This study aimed to determine whether the rate of clozapine use, an indicator of refractoriness in schizophrenia, is associated with the season of birth and age at onset in patients with schizophrenia based on nationwide data.

METHODS

Patients with schizophrenia (n = 114 749) who received prescriptions for antipsychotic medication between 2008 and 2014 were retrospectively identified from the Korean National Health Insurance Service database. The study population was divided into three groups based on their age at the onset of schizophrenia (early, middle, and late onset). We assessed differences in the month of birth between patients and the general population. In addition, the cumulative clozapine use was calculated.

RESULTS

Compared to the late-onset schizophrenia group, the early- and middle-onset groups showed a higher probability of birth during the winter season. In addition, the early-onset group showed the highest cumulative clozapine use rate. In the middle-onset group, the initiation of clozapine use was significantly earlier for patients born in winter compared to those born in summer.

CONCLUSION

Our results indicate that the age at onset is an important factor in predicting the prognosis of schizophrenia patients. The season of birth also affects the prognosis, but with less robustness. Specifically, it appears that early disease onset and winter birth might be associated with poor outcomes in Korean patients with schizophrenia.

Animal models for bipolar disorder: from bedside to the cage

Bipolar disorder is characterized by recurrent manic and depressive episodes. Patients suffering from this disorder experience dramatic mood swings with a wide variety of typical behavioral facets, affecting overall activity, energy, sexual behavior, sense of self, self-esteem, circadian rhythm, cognition, and increased risk for suicide. Effective treatment options are limited and diagnosis can be complicated. To overcome these obstacles, a better understanding of the neurobiology underlying bipolar disorder is needed. Animal models can be useful tools in understanding brain mechanisms associated with certain behavior. The following review discusses several pathological aspects of humans suffering from bipolar disorder and compares these findings with insights obtained from several animal models mimicking diverse facets of its symptomatology. Various sections of the review concentrate on specific topics that are relevant in human patients, namely circadian rhythms, neurotransmitters, focusing on the dopaminergic system, stressful environment, and the immune system. We then explain how these areas have been manipulated to create animal models for the disorder. Even though several approaches have been conducted, there is still a lack of adequate animal models for bipolar disorder. Specifically, most animal models mimic only mania or depression and only a few include the cyclical nature of the human condition. Future studies could therefore focus on modeling both episodes in the same animal model to also have the possibility to investigate the switch from mania-like behavior to depressive-like behavior and vice versa. The use of viral tools and a focus on circadian rhythms and the immune system might make the creation of such animal models possible.

Immune activation in lactating dams alters sucklings' brain cytokines and produces non-overlapping behavioral deficits in adult female and male offspring: A novel neurodevelopmental model of sex-specific psychopathology

Early immune activation (IA) in rodents, prenatal through the mother or early postnatal directly to the neonate, is widely used to produce behavioral endophenotypes relevant to schizophrenia and depression. Given that maternal immune response plays a crucial role in the deleterious effects of prenatal IA, and lactation is a critical vehicle of immunological support to the neonate, we predicted that immune activation of the lactating dam will produce long-term abnormalities in the sucklings. Nursing dams were injected on postnatal day 4 with the viral mimic poly-I:C (4mg/kg) or saline. Cytokine assessment was performed in dams' plasma and milk 2h, and in the sucklings' hippocampus, 6h and 24h following poly-I:C injection. Male and female sucklings were assessed in adulthood for: a) performance on behavioral tasks measuring constructs considered relevant to schizophrenia (selective attention and executive control) and depression (despair and anhedonia); b) response to relevant pharmacological treatments; c) brain structural changes. Maternal poly-I:C injection caused cytokine alterations in the dams' plasma and milk, as well as in the sucklings' hippocampus. Lactational poly-I:C exposure led to sex-dimorphic (non-overlapping) behavioral abnormalities in the adult offspring, with male but not female offspring exhibiting attentional and executive function abnormalities (manifested in persistent latent inhibition and slow reversal) and hypodopaminergia, and female but not male offspring exhibiting despair and anhedonia (manifested in increased immobility in the forced swim test and reduced saccharine preference) and hyperdopaminergia, mimicking the known sex-bias in schizophrenia and depression. The behavioral double-dissociation predicted distinct pharmacological profiles, recapitulating the pharmacology of negative/cognitive symptoms and depression. In-vivo imaging revealed hippocampal and striatal volume reductions in both sexes, as found in both disorders. This is the first evidence for the emergence of long-term behavioral and brain abnormalities after lactational exposure to an inflammatory agent, supporting a causal link between early immune activation and disrupted neuropsychodevelopment. That such exposure produces schizophrenia- or depression-like phenotype depending on sex, resonates with notions that risk factors are transdiagnostic, and that sex is a susceptibility factor for neurodevelopmental psychopathologies.

Common developmental genome deprogramming in schizophrenia - Role of Integrative Nuclear FGFR1 Signaling (INFS)

The watershed-hypothesis of schizophrenia asserts that over 200 different mutations dysregulate distinct pathways that converge on an unspecified common mechanism(s) that controls disease ontogeny. Consistent with this hypothesis, our RNA-sequencing of neuron committed cells (NCCs) differentiated from established iPSCs of 4 schizophrenia patients and 4 control subjects uncovered a dysregulated transcriptome of 1349 mRNAs common to all patients. Data reveals a global dysregulation of developmental genome, deconstruction of coordinated mRNA networks, and the formation of aberrant, new coordinated mRNA networks indicating a concerted action of the responsible factor(s). Sequencing of miRNA transcriptomes demonstrated an overexpression of 16 miRNAs and deconstruction of interactive miRNA-mRNA networks in schizophrenia NCCs. ChiPseq revealed that the nuclear (n) form of FGFR1, a pan-ontogenic regulator, is overexpressed in schizophrenia NCCs and overtargets dysregulated mRNA and miRNA genes. The nFGFR1 targeted 54% of all human gene promoters and 84.4% of schizophrenia dysregulated genes. The upregulated genes reside within major developmental pathways that control neurogenesis and neuron formation, whereas downregulated genes are involved in oligodendrogenesis. Our results indicate (i) an early (preneuronal) genomic etiology of schizophrenia, (ii) dysregulated genes and new coordinated gene networks are common to unrelated cases of schizophrenia, (iii) gene dysregulations are accompanied by increased nFGFR1-genome interactions, and (iv) modeling of increased nFGFR1 by an overexpression of a nFGFR1 lead to up or downregulation of selected genes as observed in schizophrenia NCCs. Together our results designate nFGFR1 signaling as a potential common dysregulated mechanism in investigated patients and potential therapeutic target in schizophrenia.

Attention-Deficit/Hyperactivity Disorder in Offspring of Mothers With Inflammatory and Immune System Diseases

BACKGROUND

Prenatal inflammatory mechanisms may play a role in the pathogenesis of psychiatric disorders and could be relevant for attention-deficit/hyperactivity disorder (ADHD). We investigated maternal chronic somatic diseases with immune components as possible risk factors for ADHD in offspring.

METHODS

We performed a population-based nested case-control study by linking data from longitudinal Norwegian registers. We included all individuals born during the period 1967-2008 and alive at record linkage (2012). Individuals receiving ADHD medication during the years 2004-2012 were defined as patients with ADHD (N = 47,944), and all remaining individuals (N = 2,274,713) were defined as control subjects. The associations between maternal diseases and ADHD in offspring were analyzed using logistic regression models.

RESULTS

The following chronic diseases with immune components were related to ADHD in offspring: multiple sclerosis (adjusted odds ratio [OR] = 1.8; 95% confidence interval [CI] = 1.2-2.5), rheumatoid arthritis (adjusted OR = 1.7; 95% CI = 1.5-1.9), type 1 diabetes (adjusted OR = 1.6; 95% CI = 1.3-2.0), asthma (adjusted OR = 1.5; 95% CI = 1.4-1.6), and hypothyroidism (adjusted OR = 1.2; 95% CI = 1.1-1.4). In contrast, chronic hypertension and type 2 diabetes showed no significant associations. Estimates were almost unchanged with additional adjustment for parental ADHD, infant birth weight, and gestational age. Although point estimates for male and female offspring were different for some diseases (e.g., maternal asthma [adjusted OR = 1.7; 95% CI = 1.5-1.8 for female offspring and adjusted OR = 1.5; 95% CI = 1.4-1.6 for male offspring]), none of the associations differed significantly by offspring sex.

CONCLUSIONS

Several maternal somatic diseases with immune components were found to increase the risk of ADHD in offspring. The associations could involve several causal pathways, including common genetic predisposition and environmental factors, and increased insight into the mechanisms behind these relationships could enhance our understanding of the etiology of ADHD.

Genome-wide DNA Methylation Changes in a Mouse Model of Infection-Mediated Neurodevelopmental Disorders

BACKGROUND

Prenatal exposure to infectious or inflammatory insults increases the risk of neurodevelopmental disorders. Using a well-established mouse model of prenatal viral-like immune activation, we examined whether this pathological association involves genome-wide DNA methylation differences at single nucleotide resolution.

METHODS

Prenatal immune activation was induced by maternal treatment with the viral mimetic polyriboinosinic-polyribocytidylic acid in middle or late gestation. Following behavioral and cognitive characterization of the adult offspring (n = 12 per group), unbiased capture array bisulfite sequencing was combined with subsequent matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and quantitative real-time polymerase chain reaction analyses to quantify DNA methylation changes and transcriptional abnormalities in the medial prefrontal cortex of immune-challenged and control offspring. Gene ontology term enrichment analysis was used to explore shared functional pathways of genes with differential DNA methylation.

RESULTS

Adult offspring of immune-challenged mothers displayed hyper- and hypomethylated CpGs at numerous loci and at distinct genomic regions, including genes relevant for gamma-aminobutyric acidergic differentiation and signaling (e.g., Dlx1, Lhx5, Lhx8), Wnt signaling (Wnt3, Wnt8a, Wnt7b), and neural development (e.g., Efnb3, Mid1, Nlgn1, Nrxn2). Altered DNA methylation was associated with transcriptional changes of the corresponding genes. The epigenetic and transcriptional effects were dependent on the offspring's age and were markedly influenced by the precise timing of prenatal immune activation.

CONCLUSIONS

Prenatal viral-like immune activation is capable of inducing stable DNA methylation changes in the medial prefrontal cortex. These long-term epigenetic modifications are a plausible mechanism underlying the disruption of prefrontal gene transcription and behavioral functions in subjects with prenatal infectious histories.

Gestational maternal C--reactive protein and risk of bipolar disorder among young individuals in a Nationwide Birth Cohort

OBJECTIVES

C-reactive protein (CRP) is a well-established general marker of inflammation from both infectious and noninfectious exposures. Previous studies have shown that maternal CRP is associated with an increased risk of autism and schizophrenia. The aim of this study was to examine the association between early to mid-gestational serum CRP levels, prospectively assayed in maternal sera, and the risk of bipolar disorder (BPD).

METHODS

This study is derived from the Finnish Prenatal Study of Bipolar Disorder (FIPS-B), based on a nested case-control study design. A total of 378 BPD cases and 378 controls, matched on date of birth and sex, with available maternal sera were identified from Finnish nationwide registers. Maternal CRP levels were assessed using a latex immunoassay from archived maternal serum specimens, collected primarily during the first and second trimesters of pregnancy.

RESULTS

Increasing maternal CRP, examined as a continuous variable, was not associated with BPD (OR=0.92, 95% CI: 0.81-1.05, p=0.24). The result did not change appreciably following adjustment for potential confounders. There were no associations between CRP in the highest quintile or decile, compared with their respective reference groups, and BPD.

LIMITATIONS

The limitations of the study include: relative young age of the cohort and availability only of a single marker of inflammation.

CONCLUSIONS

In contrast to previous findings on schizophrenia and autism, gestational maternal serum CRP levels were not associated with an increased risk of BPD. It is likely that maternal inflammation may be an additional factor that differentiates schizophrenia from BPD.

Interaction Effects of Season of Birth and Cytokine Genes on Schizotypal Traits in the General Population

Literature suggests that the effect of winter birth on vulnerability to schizophrenia might be mediated by increased expression of proinflammatory cytokines due to prenatal infection and its inadequate regulation by anti-inflammatory factors. As the response of the immune system depends on genotype, this study assessed the interaction effects of cytokine genes and season of birth (SOB) on schizotypy measured with the Schizotypal Personality Questionnaire (SPQ-74). We searched for associations of IL1B rs16944, IL4 rs2243250, and IL-1RN VNTR polymorphisms, SOB, and their interactions with the SPQ-74 total score in a sample of 278 healthy individuals. A significant effect of the IL4 X SOB interaction was found, p = 0.007 and η² = 0.028. We confirmed this effect using an extended sample of 373 individuals. Homozygotes CC born in winter showed the highest SPQ total score and differed significantly from winter-born T allele carriers, p = 0.049. This difference was demonstrated for cognitive-perceptual and disorganized but not interpersonal dimensions. The findings are consistent with the hypothesis that the cytokine genes by SOB interaction can influence variability of schizotypal traits in the general population. The IL4 T allele appeared to have a protective effect against the development of positive and disorganized schizotypal traits in winter-born individuals.

Transgenerational transmission and modification of pathological traits induced by prenatal immune activation

Prenatal exposure to infectious or inflammatory insults is increasingly recognized to contribute to the etiology of psychiatric disorders with neurodevelopmental components, including schizophrenia, autism and bipolar disorder. It remains unknown, however, if such immune-mediated brain anomalies can be transmitted to subsequent generations. Using an established mouse model of prenatal immune activation by the viral mimetic poly(I:C), we show that reduced sociability and increased cued fear expression are similarly present in the first- and second-generation offspring of immune-challenged ancestors. We further demonstrate that sensorimotor gating impairments are confined to the direct descendants of infected mothers, whereas increased behavioral despair emerges as a novel phenotype in the second generation. These transgenerational effects are mediated via the paternal lineage and are stable until the third generation, demonstrating transgenerational non-genetic inheritance of pathological traits following in-utero immune activation. Next-generation sequencing further demonstrated unique and overlapping genome-wide transcriptional changes in first- and second-generation offspring of immune-challenged ancestors. These transcriptional effects mirror the transgenerational effects on behavior, showing that prenatal immune activation leads to a transgenerational transmission (presence of similar phenotypes across generations) and modification (presence of distinct phenotypes across generations) of pathological traits. Together, our study demonstrates for, we believe, the first time that prenatal immune activation can negatively affect brain and behavioral functions in multiple generations. These findings thus highlight a novel pathological aspect of this early-life adversity in shaping disease risk across generations.

Antisera against Neisseria gonorrhoeae cross-react with specific brain proteins of the common marmoset monkey and other nonhuman primate species

Prenatal maternal infections with Neisseria gonorrhoeae (NG) correlate with an increased lifetime probability for the offspring to develop psychosis. We could previously demonstrate that in human choroid plexus papilloma cells, anti-NG antibodies (α-NG) bind to mitochondrial proteins HSP60 and ATPB, and interfere with cellular energy metabolism. To assess the in vivo relevance for this, especially during prenatal neural development, we investigated here interactions of NG-specific antisera (α-NG1, α-NG2) with brain, choroid plexus and other non-neural tissues in pre- and perinatal samples of the nonhuman primate (NHP) Callithrix jacchus (CJ), a NHP model for preclinical research. In histological sections at embryonic day E75, immunohistochemistry revealed α-NG1 and -2-staining in choroid plexus, ganglionic hill, optic cup, heart, and liver. Within the cells, organelle-like structures were labeled, which could be identified by immunohistochemical double-labeling as mitochondria. Both one- and two-dimensional Western blot analysis revealed tissue specific patterns of α-NG1 immunoreactive bands and spots, respectively, which were subsequently characterized by mass spectrometry. Thereby we could confirm the interactions of α-NG1 with human HSP60 and ATPB also in CJ choroid plexus and liver. Even more important, in the CJ brain, several new targets, including NCAM1, CRMP2, and SYT1, were identified, which by unrelated studies have been previously suggested to correlate with an increased schizophrenia risk. These findings support the idea that the marmoset monkey is a useful NHP model to investigate the role of maternal bacterial infections during prenatal brain development, and thereby might improve the understanding of this important aspect of schizophrenia pathology.

The effects of prenatal H1N1 infection at E16 on FMRP, glutamate, GABA, and reelin signaling systems in developing murine cerebellum

Prenatal viral infection has been identified as a potential risk factor for the development of neurodevelopmental disorders such as schizophrenia and autism. Additionally, dysfunction in gamma-aminobutyric acid, Reelin, and fragile X mental retardation protein (FMRP)-metabotropic glutamate receptor 5 signaling systems has also been demonstrated in these two disorders. In the current report, we have characterized the developmental profiles of selected markers for these systems in cerebella of mice born to pregnant mice infected with human influenza (H1N1) virus on embryonic day 16 or sham-infected controls using SDS-PAGE and Western blotting techniques and evaluated the presence of abnormalities in the above-mentioned markers during brain development. The cerebellum was selected in light of emerging evidence that it plays roles in learning, memory, and emotional processing-all of which are disrupted in autism and schizophrenia. We identified unique patterns of gene and protein expression at birth (postnatal day 0 [P0]), childhood (P14), adolescence (P35), and young adulthood (P56) in both exposed and control mouse progeny. We also identified significant differences in protein expression for FMRP, very-low-density lipoprotein receptor, and glutamic acid decarboxylase 65 and 67 kDa proteins at specific postnatal time points in cerebella of the offspring of exposed mice. Our results provide evidence of disrupted FMRP, glutamatergic, and Reelin signaling in the exposed mouse offspring that explains the multiple brain abnormalities observed in this animal model. © 2016 Wiley Periodicals, Inc.

Supra-therapeutic plasma concentrations of haloperidol induce moderate inhibition of lipopolysaccharide-induced interleukin-8 release in human monocytes

BACKGROUND

The clinical use of antipsychotics and mood-stabilizing drugs with proven efficacy is largely determined by the occurrence of treatment-emergent adverse events and routine clinical chemistry and haematology data, which together define the safety and tolerability profile of these psychopharmaceuticals. Whereas the effects of mood-stabilizing drugs on functional properties of blood cells have been poorly investigated, the effects of antipsychotics have received more attention. Such studies have yielded conflicting results. This study examined the effects of the mood-stabilizing drugs carbamazepine and valproic acid and of the antipsychotic drugs olanzapine, risperidone and haloperidol on the production of the pro-inflammatory chemokine interleukin-8 (IL-8), which is released from human monocytes when activated by Gram-negative lipopolysaccharide (LPS).

METHODS

Peripheral human whole blood was diluted with Roswell Park Memorial Institute (RPMI) cell culture medium and stimulated with LPS. Accumulating IL-8 was quantified in the supernatant with an adapted enzyme-linked immunosorbent assay (ELISA) and the results correlated to the number of monocytes at venipuncture.

RESULTS

At supra-therapeutic concentrations of 100 µM, haloperidol inhibited the LPS-induced release of IL-8 in peripheral human monocytes moderately, whereas olanzapine, risperidone, carbamazepine and valproic acid showed no such effect.

CONCLUSIONS

The results suggest that these mood-stabilizing drugs and antipsychotics are endowed with clinically favorable inertness rather than pro-inflammatory properties.

Prenatal and Newborn Immunoglobulin Levels from Mother-Child Pairs and Risk of Autism Spectrum Disorders

Background: An etiological role for immune factors operating during early brain development in children with autism spectrum disorders (ASD) has not yet been established. A major obstacle has been the lack of early biologic specimens that can be linked to later diagnosis. In a prior study, we found lower risk of ASD associated with higher levels of maternally-derived total IgG and Toxoplasmosis gondii (Toxo) IgG in newborn blood spot specimens from children later diagnosed with ASD compared to population controls.

Methods: We obtained maternal mid-gestational serum specimens and newborn screening blood spots from the California Genetics Disease Screening Program (GDSP) for linked mother-baby pairs for 84 children with ASD and 49 children with developmental delay but not ASD (DD) identified from California Department of Developmental Services records and for 159 population controls sampled from birth certificates.Immunoglobulin levels in maternal and newborn specimens were measured by solid phase immunoassays and analyzed in logistic regression models for total IgG, total IgM, and Toxo IgG, and, for maternal specimens only, Toxo IgM. Correlations between maternal and newborn ranked values were evaluated.

Results: In both maternal and newborn specimens, we found significantly lower risk of ASD associated with higher levels of Toxo IgG. In addition, point estimates for all comparisons were < 1.0 suggesting an overall pattern of lower immunoglobulin levels associated with higher ASD risk but most did not reach statistical significance. We did not find differences in maternal or newborn specimens comparing children with DD to controls.

Discussion: These results are consistent with evidence from our prior study and other published reports indicating that immune factors during early neurodevelopment may be etiologically relevant to ASD. Lowered immunoglobulin levels may represent suboptimal function of the maternal immune system or reduced maternal exposure to common infectious agents.

Conclusion: Patterns seen in these selected immunoglobulins may provide clues to mechanisms of early abnormalities in neurodevelopment contributing to ASD. We recommend further study of immunoglobulin profiles in larger samples of linked mother-baby pairs to evaluate possible etiologic relevance.

Altered interleukin-18 levels are associated with cognitive impairment in chronic schizophrenia

The pathophysiology of cognitive deficits in schizophrenia may involve the neuroinflammation mediated by cytokines. This study examined the IL-18 levels, the cognitive function, and their association in schizophrenia. We recruited 70 chronic patients and 75 normal controls and examined the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and IL-18 levels. Positive and Negative Syndrome Scale (PANSS) was assessed in chronic patients. IL-18 levels were increased in chronic patients as compared to normal controls (p < 0.01). RBANS total score and the subscales of immediate memory and delayed memory were lower in patients than controls (all p < 0.001). In patients, IL-18 levels were positively associated with RBANS total score and the subscales of immediate and delayed memory (all p < 0.05). Multiple regression analysis further confirmed that IL-18 was an independent contributor to RBANS total score and the aforementioned two indexes (all p < 0.05). Our data demonstrate that immune responses may play an important role in cognitive deficits in schizophrenia and the abnormal levels of IL-18 reflecting the disturbed balance of proinflammatory and anti-inflammatory mechanisms may be relevant to cognitive deficits of this disorder.

Potential involvement of the interleukin-18 pathway in schizophrenia

OBJECTIVE

Accumulating evidence implicates inflammatory cytokines in the development of psychiatric disorders, including schizophrenia (SZ). IL-18 is one of cytokines that plays a crucial role in immune response and neurodevelopment. We aimed to investigate potential genetic alterations of the cytokine system underpinning SZ.

METHODS

We tested the association of genetic variants within the cytokine-cytokine receptor interaction (CCRI) pathway with SZ, using GWAS-derived data involving 768 adult SZ patients and 1348 controls, and replicated the association of IL18R1 rs1035130 with SZ in an independent sample of 1957 adult patients and 1509 controls. We compared expression levels of IL18, IL18R1 and IL18RAP in peripheral blood of a cohort of adolescent participants (<18 years), including 14 early-onset SZ patients and 13 healthy controls. Furthermore, we carried out a cis-eQTL (expression Quantitative Trait Loci) and a cis-mQTL (Methylation Quantitative Trait Loci) analysis for IL18R1 rs1035130.

RESULTS

In the discovery stage, we detected association signals within two IL18 pathway genes, IL18R1 and IL18RAP, with the most significant marker being IL18R1 rs1035130 (P = 1.84E-7, OR = 0.70). In the validation stage, we found rs1035130 was associated with SZ (P = 0.028, OR = 0.89). Expressions of IL18 and IL18R1 were altered in blood of SZ patients compared with 13 controls. Furthermore, cis-QTL analyses indicated that rs1035130 was associated with an eQTL and 5 mQTLs.

CONCLUSION

Our findings suggest the alteration of IL18 pathway may contribute to the psychopathology of SZ.

Flow cytometric characterization of microglia in the offspring of PolyI:C treated mice

The neuropathology of schizophrenia has been reported to be closely associated with microglial activation. In a previous study, using the prenatal PolyI:C schizophrenia animal model, we showed an increase in cell numbers and a reduction in microglial branching in 30-day-old PolyI:C descendants, which suggests that there is microglial activation during adolescence. To provide more information about the activation state, we aimed to examine the expression levels of Iba1, which was reported to be up-regulated in activated microglia. We used a flow cytometric approach and investigated CD11b and CD45, two additional markers for the identification of microglial cells. We demonstrated that intracellular staining against Iba1 can be used as a reliable flow cytometric method for identification of microglial cells. Prenatal PolyI:C treatment had long-term effects on CD11b and CD45 expression. It also resulted in a trend towards increased Iba1 expression. Imbalance in CD11b, CD45, and Iba1 expression might contribute to impaired synaptic surveillance and enhanced activation/inflammatory activity of microglia in adult offspring.

Linking early-life NMDAR hypofunction and oxidative stress in schizophrenia pathogenesis

Molecular, genetic and pathological evidence suggests that deficits in GABAergic parvalbumin-positive interneurons contribute to schizophrenia pathophysiology through alterations in the brain's excitation-inhibition balance that result in impaired behaviour and cognition. Although the factors that trigger these deficits are diverse, there is increasing evidence that they converge on a common pathological hub that involves NMDA receptor hypofunction and oxidative stress. These factors have been separately linked to schizophrenia pathogenesis, but evidence now suggests that they are mechanistically interdependent and contribute to a common schizophrenia-associated pathology.

Changes in Astroglial Markers in a Maternal Immune Activation Model of Schizophrenia in Wistar Rats are Dependent on Sex

Data from epidemiological studies suggest that prenatal exposure to bacterial and viral infection is an important environmental risk factor for schizophrenia. The maternal immune activation (MIA) animal model is used to study how an insult directed at the maternal host can have adverse effects on the fetus, leading to behavioral and neurochemical changes later in life. We evaluated whether the administration of LPS to rat dams during late pregnancy affects astroglial markers (S100B and GFAP) of the offspring in later life. The frontal cortex and hippocampus were compared in male and female offspring on postnatal days (PND) 30 and 60. The S100B protein exhibited an age-dependent pattern of expression, being increased in the frontal cortex and hippocampus of the MIA group at PND 60, while at PND 30, male rats presented increased S100B levels only in the frontal cortex. Considering that S100B secretion is reduced by elevation of glutamate levels, we may hypothesize that this early increment in frontal cortex tissue of males is associated with elevated extracellular levels of glutamate and glutamatergic hypofunction, an alteration commonly associated with SCZ pathology. Moreover, we also found augmented GFAP in the frontal cortex of the LPS group at PND 30, but not in the hippocampus. Taken together data indicate that astroglial changes induced by MIA are dependent on sex and brain region and that these changes could reflect astroglial dysfunction. Such alterations may contribute to our understanding of the abnormal neuronal connectivity and developmental aspects of SCZ and other psychiatric disorders.

Loss of Metabotropic Glutamate Receptor 5 Function on Peripheral Benzodiazepine Receptor in Mice Prenatally Exposed to LPS

Parental microglial induced neuroinflammation, triggered by bacterial- or viral infections, can induce neuropsychiatric disorders like schizophrenia and autism to offspring in animal models. Recent investigations suggest that microglia, the resident immune cells of the brain, provides a link between neurotransmission, immune cell activation, brain inflammation and neuronal dysfunction seen with the offspring. Relatively little is known about how reduction of brain inflammation and restoration of glial function are associated with diminution of brain degeneration and behavioral deficits in offspring. Increased mGluR5 expression and the long-lasting excitotoxic effects of the neurotoxin during brain development are associated with the glial dysfunctions. We investigated the relationship of mGluR5 and PBR and how they regulate glial function and inflammatory processes in mice prenatally exposed to LPS (120μg/kg, between gestational days 15 and 17), an inflammatory model of a psychiatric disorder. Using PET imaging, we showed that pharmacological activation of mGluR5 during 5 weeks reduced expression of classic inflammation marker PBR in many brain areas and that this molecular association was not present in LPS-exposed offspring. The post-mortem analysis revealed that the down regulation of PBR was mediated through activation of mGluR5 in astrocytes. In addition, we demonstrated that this interaction is defective in a mouse model of the psychiatric deficit offering a novel insight of mGluR5 involvement to brain related disorders and PBR related imaging studies. In conclusion, mGluR5 driven glutamatergic activity regulates astrocytic functions associated with PBR (cholesterol transport, neurosteroidogenesis, glial phenotype) during maturation and could be associated with neuropsychiatric disorders in offspring.

Fever and sickness behavior: Friend or foe?

Fever has been recognized as an important symptom of disease since ancient times. For many years, fever was treated as a putative life-threatening phenomenon. More recently, it has been recognized as an important part of the body's defense mechanisms; indeed at times it has even been used as a therapeutic agent. The knowledge of the functional role of the central nervous system in the genesis of fever has greatly improved over the last decade. It is clear that the febrile process, which develops in the sick individual, is just one of many brain-controlled sickness symptoms. Not only will the sick individual appear "feverish" but they may also display a range of behavioral changes, such as anorexia, fatigue, loss of interest in usual daily activities, social withdrawal, listlessness or malaise, hyperalgesia, sleep disturbances and cognitive dysfunction, collectively termed "sickness behavior". In this review we consider the issue of whether fever and sickness behaviors are friend or foe during: a critical illness, the common cold or influenza, in pregnancy and in the newborn. Deciding whether these sickness responses are beneficial or harmful will very much shape our approach to the use of antipyretics during illness.

Inhibition of MAPK/ERK signaling blocks hippocampal neurogenesis and impairs cognitive performance in prenatally infected neonatal rats

Hippocampus endogenous neurogenesis has been postulated to play a favorable role in brain restoration after injury. However, the underlying molecular mechanisms have been insufficiently deciphered. Here we investigated the potential regulatory capacity of MAPK/ERK signaling on neurogenesis and the associated cognitive performance in prenatally infected neonatal rats. From our data, intrauterine infection could induce hippocampal neuronal apoptosis and promote endogenous repair by evoking neural stem cell proliferation and survival. We also found intrauterine infection could induce increased levels of p-ERK, p-CREB and BDNF, which might be responsible for the potential endogenous rescue system. Furthermore, inhibition of MAPK/ERK signaling could aggravate hippocampal neuronal apoptosis, decrease neurogenesis, and impair the offspring's cognitive performances and could also down-regulate the levels of p-ERK, p-CREB and BDNF. Our data strongly suggest that the activation of MAPK/ERK signaling may play a significant role in promoting survival of newly generated neural stem cells via an anti-apoptotic mechanism, which may be particularly important in endogenous neuroprotection associated with cognitive performance development in prenatally infected rats.

Ghrelin-reactive immunoglobulins and anxiety, depression and stress-induced cortisol response in adolescents. The TRAILS study

BACKGROUND

Ghrelin, a hunger hormone, has been implicated in the regulation of stress-response, anxiety and depression. Ghrelin-reactive immunoglobulins (Ig) were recently identified in healthy and obese humans showing abilities to increase ghrelin's stability and orexigenic effects. Here we studied if ghrelin-reactive Ig are associated with anxiety and depression and with the stress-induced cortisol response in a general population of adolescents. Furthermore, to test the possible infectious origin of ghrelin-reactive Ig, their levels were compared with serum IgG against common viruses.

METHODS

We measured ghrelin-reactive IgM, IgG and IgA in serum samples of 1199 adolescents from the Dutch TRAILS study and tested their associations with 1) anxiety and depression symptoms assessed with the Youth Self-Report, 2) stress-induced salivary cortisol levels and 3) IgG against human herpesvirus 1, 2, 4 and 6 and Influenza A and B viruses.

RESULTS

Ghrelin-reactive IgM and IgG correlated positively with levels of antibodies against Influenza A virus. Ghrelin-reactive IgM correlated negatively with antibodies against Influenza B virus. Ghrelin-reactive IgM correlated positively with anxiety scores in girls and ghrelin-reactive IgG correlated with stress-induced cortisol secretion, but these associations were weak and not significant after correction for multiple testing.

CONCLUSION

These data indicate that production of ghrelin-reactive autoantibodies could be influenced by viral infections. Serum levels of ghrelin-reactive autoantibodies probably do not play a role in regulating anxiety, depression and the stress-response in adolescents from the general population.

Common variants of IRF3 conferring risk of schizophrenia

Schizophrenia is a brain disorder with high heritability. Recent studies have implicated genes involved in the immune response pathway in the pathogenesis of schizophrenia. Interferon regulatory factor 3 (IRF3), a virus-immune-related gene, activates the transcription of several interferon-induced genes, and functionally interacts with several schizophrenia susceptibility genes. To test whether IRF3 is a schizophrenia susceptibility gene, we analyzed the associations of its SNPs with schizophrenia in independent population samples as well as reported data from expression quantitative trait loci (eQTL) in healthy individuals. We observed multiple independent SNPs in IRF3 showing nominally significant associations with schizophrenia (P < 0.05); more intriguingly, a SNP (rs11880923), which is significantly correlated with IRF3 expression in independent samples (P < 0.05), is also consistently associated with schizophrenia across different cohorts and in combined samples (odds ratio = 1.075, Pmeta = 2.08 × 10(-5)), especially in Caucasians (odds ratio = 1.078, Pmeta = 2.46 × 10(-5)). These results suggested that IRF3 is likely a risk gene for schizophrenia, at least in Caucasians. Although the clinical associations of IRF3 with diagnosis did not achieve genome-wide level of statistical significance, the observed odds ratio is comparable with other susceptibility loci identified through large-scale genetic association studies on schizophrenia, which could be regarded simply as small but detectable effects.

Brain in flames - animal models of psychosis: utility and limitations

The neurodevelopmental hypothesis of schizophrenia posits that schizophrenia is a psychopathological condition resulting from aberrations in neurodevelopmental processes caused by a combination of environmental and genetic factors which proceed long before the onset of clinical symptoms. Many studies discuss an immunological component in the onset and progression of schizophrenia. We here review studies utilizing animal models of schizophrenia with manipulations of genetic, pharmacologic, and immunological origin. We focus on the immunological component to bridge the studies in terms of evaluation and treatment options of negative, positive, and cognitive symptoms. Throughout the review we link certain aspects of each model to the situation in human schizophrenic patients. In conclusion we suggest a combination of existing models to better represent the human situation. Moreover, we emphasize that animal models represent defined single or multiple symptoms or hallmarks of a given disease.

Maternal immune activation and abnormal brain development across CNS disorders

Epidemiological studies have shown a clear association between maternal infection and schizophrenia or autism in the progeny. Animal models have revealed maternal immune activation (mIA) to be a profound risk factor for neurochemical and behavioural abnormalities in the offspring. Microglial priming has been proposed as a major consequence of mIA, and represents a critical link in a causal chain that leads to the wide spectrum of neuronal dysfunctions and behavioural phenotypes observed in the juvenile, adult or aged offspring. Such diversity of phenotypic outcomes in the mIA model are mirrored by recent clinical evidence suggesting that infectious exposure during pregnancy is also associated with epilepsy and, to a lesser extent, cerebral palsy in children. Preclinical research also suggests that mIA might precipitate the development of Alzheimer and Parkinson diseases. Here, we summarize and critically review the emerging evidence that mIA is a shared environmental risk factor across CNS disorders that varies as a function of interactions between genetic and additional environmental factors. We also review ongoing clinical trials targeting immune pathways affected by mIA that may play a part in disease manifestation. In addition, future directions and outstanding questions are discussed, including potential symptomatic, disease-modifying and preventive treatment strategies.

Bacterial ClpB heat-shock protein, an antigen-mimetic of the anorexigenic peptide α-MSH, at the origin of eating disorders

The molecular mechanisms at the origin of eating disorders (EDs), including anorexia nervosa (AN), bulimia and binge-eating disorder (BED), are currently unknown. Previous data indicated that immunoglobulins (Igs) or autoantibodies (auto-Abs) reactive with α-melanocyte-stimulating hormone (α-MSH) are involved in regulation of feeding and emotion; however, the origin of such auto-Abs is unknown. Here, using proteomics, we identified ClpB heat-shock disaggregation chaperone protein of commensal gut bacteria Escherichia coli as a conformational antigen mimetic of α-MSH. We show that ClpB-immunized mice produce anti-ClpB IgG crossreactive with α-MSH, influencing food intake, body weight, anxiety and melanocortin receptor 4 signaling. Furthermore, chronic intragastric delivery of E. coli in mice decreased food intake and stimulated formation of ClpB- and α-MSH-reactive antibodies, while ClpB-deficient E. coli did not affect food intake or antibody levels. Finally, we show that plasma levels of anti-ClpB IgG crossreactive with α-MSH are increased in patients with AN, bulimia and BED, and that the ED Inventory-2 scores in ED patients correlate with anti-ClpB IgG and IgM, which is similar to our previous findings for α-MSH auto-Abs. In conclusion, this work shows that the bacterial ClpB protein, which is present in several commensal and pathogenic microorganisms, can be responsible for the production of auto-Abs crossreactive with α-MSH, associated with altered feeding and emotion in humans with ED. Our data suggest that ClpB-expressing gut microorganisms might be involved in the etiology of EDs.

Pharmacological characterization of cultivated neuronal networks: relevance to synaptogenesis and synaptic connectivity

Mental disorders, such as schizophrenia or Alzheimer's disease, are associated with impaired synaptogenesis and/or synaptic communication. During development, neurons assemble into neuronal networks, the primary supracellular mediators of information processing. In addition to the orchestrated activation of genetic programs, spontaneous electrical activity and associated calcium signaling have been shown to be critically involved in the maturation of such neuronal networks. We established an in vitro model that recapitulates the maturation of neuronal networks, including spontaneous electrical activity. Upon plating, mouse primary hippocampal neurons grow neurites and interconnect via synapses to form a dish-wide neuronal network. Via live cell calcium imaging, we identified a limited period of time in which the spontaneous activity synchronizes across neurons, indicative of the formation of a functional network. After establishment of network activity, the neurons grow dendritic spines, the density of which was used as a morphological readout for neuronal maturity and connectivity. Hence, quantification of neurite outgrowth, synapse density, spontaneous neuronal activity, and dendritic spine density allowed to study neuronal network maturation from the day of plating until the presence of mature neuronal networks. Via acute pharmacological intervention, we show that synchronized network activity is mediated by the NMDA-R. The balance between kynurenic and quinolinic acid, both neuro-active intermediates in the tryptophan/kynurenine pathway, was shown to be decisive for the maintenance of network activity. Chronic modulation of the neurotrophic support influenced the network formation and revealed the extreme sensitivity of calcium imaging to detect subtle alterations in neuronal physiology. Given the reproducible cultivation in a 96-well setup in combination with fully automated analysis of the calcium recordings, this approach can be used to build a high-content screening assay usable for neurotoxicity screening, target identification/validation, or phenotypic drug screening.

Minocycline improves recognition memory and attenuates microglial activation in Gunn rat: a possible hyperbilirubinemia-induced animal model of schizophrenia

BACKGROUND

Accumulating evidence indicates that neuroinflammation plays a significant role in the pathophysiology of schizophrenia. We previously reported evidence of schizophrenia-like behaviors and microglial activation in Gunn rats. We concluded that the Gunn rat, which exhibits a high concentration of unconjugated bilirubin, may be useful as an animal model of schizophrenia. On the other hand, there have been numerous reports that minocycline is effective in treating schizophrenia.

METHODS

In the present study, we investigated the effects of minocycline on performance of behavioral tests (prepulse inhibition (PPI) and novel object recognition test (NORT)) after animals received either 40mg/kg/d of minocycline or vehicle by intraperitoneal (i.p.) injection for 14 consecutive days. Furthermore, we examined the effects of minocycline on microglial activation in the hippocampal dentate gyrus of Gunn rats and Wistar rats.

RESULTS

We found that administration of minocycline for 14days significantly increased the exploratory preference in retention sessions and tended to improve the PPI deficits in Gunn rats. Immunohistochemistry analysis revealed that microglial cells in the minocycline-treated Gunn rat group showed less expression of CD11b compared to vehicle-treated Gunn and Wistar groups.

CONCLUSIONS

Our findings suggest that minocycline improves recognition memory and attenuates microglial activation in the hippocampal dentate gyrus of Gunn rats. Therefore, minocycline may be a potential therapeutic drug for schizophrenia.

Antibodies directed to the gram-negative bacterium Neisseria gonorrhoeae cross-react with the 60 kDa heat shock protein and lead to impaired neurite outgrowth in NTera2/D1 cells

Children of mothers with prenatal gonococcal infections are of increased risk to develop schizophrenic psychosis in later life. The present study hypothesizes an autoimmune mechanism for this, investigating interactions of a commercial rabbit antiserum directed to Neisseria gonorrhoeae (α-NG) with human NTera2/D1 cells, an established in vitro model for human neuronal differentiation. Immunocytochemistry demonstrated α-NG to label antigens on an intracellular organelle, which by Western blot analysis showed a molecular weight shortly below 72 kDa. An antiserum directed to Neisseria meningitidis (α-NM) reacts with an antigen shortly below 95 kDa, confirming antibody specificity of these interactions. Two-dimensional gel electrophoresis and partial Western transfer, allowed to localize an α-NG reactive protein spot which was identified by LC-Q-TOF MS/MS analysis as mitochondrial heat shock protein Hsp60. This was confirmed by Western blot analysis of α-NG immunoreactivity with a commercial Hsp60 protein sample, with which α-NM failed to interact. Finally, analysis of neurite outgrowth in retinoic acid-stimulated differentiating NTera2-D1 cells, demonstrates that α-NG but not α-NM treatment reduces neurite length. These results demonstrate that α-NG can interact with Hsp60 in vitro, whereas pathogenetic relevance of this interaction for psychotic symptomatology remains to be clarified.

Prenatal poly(i:C) exposure and other developmental immune activation models in rodent systems

It is increasingly appreciated that altered neuroimmune mechanisms might play a role in the development of schizophrenia and related psychotic illnesses. On the basis of human epidemiological findings, a number of translational rodent models have been established to explore the consequences of prenatal immune activation on brain and behavioral development. The currently existing models are based on maternal gestational exposure to human influenza virus, the viral mimic polyriboinosinic-polyribocytidilic acid [Poly(I:C)], the bacterial endotoxin lipopolysaccharide, the locally acting inflammatory agent turpentine, or selected inflammatory cytokines. These models are pivotal for establishing causal relationships and for identifying cellular and molecular mechanisms that affect normal brain development in the event of early-life immune exposures. An important aspect of developmental immune activation models is that they allow a multi-faceted, longitudinal monitoring of the disease process as it unfolds during the course of neurodevelopment from prenatal to adult stages of life. An important recent refinement of these models is the incorporation of multiple etiologically relevant risk factors by combining prenatal immune challenges with specific genetic manipulations or additional environmental adversities. Converging findings from such recent experimental attempts suggest that prenatal infection can act as a "neurodevelopmental disease primer" that is likely relevant for a number of chronic mental illnesses. Hence, the adverse effects induced by prenatal infection might reflect an early entry into the neuropsychiatric route, but the specificity of subsequent disease or symptoms is likely to be strongly influenced by the genetic and environmental context in which the prenatal infectious process occurs.

A two-stage association study suggests BRAP as a susceptibility gene for schizophrenia

Schizophrenia (SZ) is a neurodevelopmental disorder in which altered immune function typically plays an important role in mediating the effect of environmental insults and regulation of inflammation. The breast cancer suppressor protein associated protein (BRAP) is suggested to exert vital effects in neurodevelopment by modulating the mitogen-activated protein kinase cascade and inflammation signaling. To explore the possible role of BRAP in SZ, we conducted a two-stage study to examine the association of BRAP polymorphisms with SZ in the Han Chinese population. In stage one, we screened SNPs in BRAP from our GWAS data, which detected three associated SNPs, with rs3782886 being the most significant one (P  =  2.31E-6, OR  =  0.67). In stage two, we validated these three SNPs in an independently collected population including 1957 patients and 1509 controls, supporting the association of rs3782886 with SZ (P  =  1.43E-6, OR  =  0.73). Furthermore, cis-eQTL analysis indicates that rs3782886 genotypes are associated with mRNA levels of aldehyde dehydrogenase 2 family (ALDH2) (P  =  0.0039) and myosin regulatory light chain 2 (MYL2) (P < 1.0E-4). Our data suggest that the BRAP gene may confer vulnerability for SZ in Han Chinese population, adding further evidence for the involvement of developmental and/or neuroinflammatory cascades in the illness.

Pre-clinical models of neurodevelopmental disorders: focus on the cerebellum

Recent studies have advanced our understanding of the role of the cerebellum in non-motor behaviors. Abnormalities in the cerebellar structure have been demonstrated to produce changes in emotional, cognitive, and social behaviors resembling clinical manifestations observed in patients with autism spectrum disorders (ASD) and schizophrenia. Several animal models have been used to evaluate the effects of relevant environmental and genetic risk factors on the cerebellum development and function. However, very few models of ASD and schizophrenia selectively target the cerebellum and/or specific cell types within this structure. In this review, we critically evaluate the strength and weaknesses of these models. We will propose that the future progress in this field will require time- and cell type-specific manipulations of disease-relevant genes, not only selectively in the cerebellum, but also in frontal brain areas connected with the cerebellum. Such information can advance our knowledge of the cerebellar contribution to non-motor behaviors in mental health and disease.

Prenatal immune activation and subsequent peripubertal stress as a new model of schizophrenia

Epidemiological studies show that maternal viral infection during pregnancy plays a key role in the etiology of neurodevelopmental disorders, such as schizophrenia and autism. Prenatal maternal immune activation and peripubertal psychological stress are key environmental risk factors for neurodevelopmental disorders. Viral mimic polyriboinosinic-polyribocytidylic acid is known to act as a Toll-like receptor-3 agonist. Polyriboinosinic-polyribocytidylic acid has been typically used to establish this rodent model of prenatal immune activation. Recently, Giovanoli et al. reported on a new neurodevelopmental model of schizophrenia based on combined prenatal immune activation and peripubertal stress. In this report, we place these findings into context and discuss their significance.

Hypolocomotive behaviour associated with increased microglia in a prenatal immune activation model with relevance to schizophrenia

Over the past decade a neurodevelopmental animal model with high validity for schizophrenia has been developed based on the environmental risk factor known as maternal immune activation (MIA). The immunological basis of this model, together with extensive data from clinical and preclinical context, suggests the involvement of an aberrant neuro-immune system in the pathophysiology of schizophrenia. The goal of this study was to examine microglia activation in adult behaviourally phenotyped MIA offspring. MIA was induced in pregnant rats using viral mimetic Poly I:C at gestational day 15. Adult offspring were behaviourally phenotyped at postnatal days (PND) 56, 90 and 180 through the evaluation of prepulse inhibition (PPI) of the acoustic startle and spontaneous locomotion. Finally, the presence of activated microglia in brain regions associated with schizophrenia was evaluated using post-mortem immunohistochemistry against OX-42 (CD11b) and ED-1 (CD68). Although a deficit in PPI could not be replicated despite the high number of animals tested, we found an overall decrease in basal startle response and spontaneous locomotion in offspring born to Poly I:C- compared to saline-treated dams, accompanied by increased microglial density with characteristics of non-reactive activation in the chronic stage of the model. These findings provide additional evidence for a role played by microglial activation in schizophrenia-related pathology in general and psychomotor slowing in particular, and warrant extensive research on the underlying mechanism in order to establish new drug targets for the treatment of schizophrenia patients with an inflammatory component.

Gene expression profiling by mRNA sequencing reveals increased expression of immune/inflammation-related genes in the hippocampus of individuals with schizophrenia

Whole-genome expression profiling in postmortem brain tissue has recently provided insight into the pathophysiology of schizophrenia. Previous microarray and RNA-Seq studies identified several biological processes including synaptic function, mitochondrial function and immune/inflammation response as altered in the cortex of subjects with schizophrenia. Now using RNA-Seq data from the hippocampus, we have identified 144 differentially expressed genes in schizophrenia cases as compared with unaffected controls. Immune/inflammation response was the main biological process over-represented in these genes. The upregulation of several of these genes, IFITM1, IFITM2, IFITM3, APOL1 (Apolipoprotein L1), ADORA2A (adenosine receptor 2A), IGFBP4 and CD163 were validated in the schizophrenia subjects using data from the SNCID database and with quantitative RT-PCR. We identified a co-expression module associated with schizophrenia that includes the majority of differentially expressed genes related to immune/inflammation response as well as with the density of parvalbumin-containing neurons in the hippocampus. The results indicate that abnormal immune/inflammation response in the hippocampus may underlie the pathophysiology of schizophrenia and may be associated with abnormalities in the parvalbumin-containing neurons that lead to the cognitive deficits of the disease.

Obstetric complications as risk factors for schizophrenia spectrum psychoses in offspring of mothers with psychotic disorder

BACKGROUND

Obstetric complications have predicted future development of schizophrenia in previous studies, but they are also more common in mothers with schizophrenia. The aims of this study were to compare the occurrence of obstetric complications in children of mothers with schizophrenia spectrum psychoses and control children, and to investigate whether obstetric complications predicted children's psychiatric morbidity.

METHOD

The Helsinki High-Risk (HR) Study monitors females born between 1916 and 1948 and treated for schizophrenia spectrum disorders in Helsinki psychiatric hospitals, their offspring born between 1941 and 1977, and controls. We examined information on obstetric complications and neonatal health of 271 HR and 242 control offspring. We compared the frequency of obstetric complications and neonatal health problems in the HR group vs controls and in HR children who later developed psychotic disorders vs healthy HR children. A Cox regression model was used to assess whether problems in pregnancy or delivery predicted psychiatric morbidity within the HR group.

RESULTS

Few differences between HR and control offspring were found in obstetric complications. Within the HR group, infections (hazard rate ratio [HRR] 3.73, 95% CI 1.27-11.01), hypertension during pregnancy (HRR 4.10, 95% CI 1.15-14.58), and placental abnormalities (HRR 4.09, 95% CI 1.59-10.49) were associated with elevated risk of schizophrenia spectrum psychoses.

CONCLUSIONS

Common medical problems during pregnancy were associated with increased risk of schizophrenia spectrum psychoses in offspring of mothers with schizophrenia spectrum psychoses. These results underline the role of the prenatal period in the development of schizophrenia and the importance of careful monitoring of pregnancies of mothers with psychotic disorder.

Mouse models of gene-environment interactions in schizophrenia

Gene-environment interactions (GEIs) likely play significant roles in the pathogenesis of schizophrenia and underlie differences in pathological, behavioral, and clinical presentations of the disease. Findings from epidemiology and psychiatric genetics have assisted in the generation of animal models of GEI relevant to schizophrenia. These models may provide a foundation for elucidating the molecular, cellular, and circuitry mechanisms that mediate GEI in schizophrenia. Here we critically review current mouse models of GEI related to schizophrenia, describe directions for their improvement, and propose endophenotypes to provide a more tangible basis for molecular studies of pathways of GEI and facilitate the identification of novel therapeutic targets.

Variation in the major histocompatibility complex [MHC] gene family in schizophrenia: associations and functional implications

Schizophrenia is a chronic debilitating neuropsychiatric disorder with a complex genetic contribution. Although multiple genetic, immunological and environmental factors are known to contribute to schizophrenia susceptibility, the underlying neurobiological mechanism(s) is yet to be established. The immune system dysfunction theory of schizophrenia is experiencing a period of renewal due to a growth in evidence implicating components of the immune system in brain function and human behavior. Current evidence indicates that certain immune molecules such as Major Histocompatibility Complex (MHC) and cytokines, the key regulators of immunity and inflammation are directly involved in the neurobiological processes related to neurodevelopment, neuronal plasticity, learning, memory and behavior. However, the strongest support in favor of the immune hypothesis has recently emerged from on-going genome wide association studies advocating MHC region variants as major determinants of one's risk for developing schizophrenia. Further identification of the interacting partners and receptors of MHC molecules in the brain and their role in down-stream signaling pathways of neurotransmission have implicated these molecules as potential schizophrenia risk factors. More recently, combined brain imaging and genetic studies have revealed a relationship between genetic variations within the MHC region and neuromorphometric changes during schizophrenia. Furthermore, MHC molecules play a significant role in the immune-infective and neurodevelopmental pathogenetic pathways, currently hypothesized to contribute to the pathophysiology of schizophrenia. Herein, we review the immunological, genetic and expression studies assessing the role of the MHC in conferring risk for developing schizophrenia, we summarize and discuss the possible mechanisms involved, making note of the challenges to, and future directions of, immunogenetic research in schizophrenia.

Effect of epigallocatechin gallate supplementation in schizophrenia and bipolar disorder: an 8-week, randomized, double-blind, placebo-controlled study

OBJECTIVES

Strategies that focus on the reduction of oxidative stress and inflammation may have therapeutic benefit for the treatment of schizophrenia. This clinical trial sought to determine, in a double-blind study, whether epigallocatechin gallate (EGCG), a green tea extract, is a useful adjunct to maintenance antipsychotic medication.

METHODS

Adults with schizophrenia, schizoaffective disorder or bipolar disorder who were maintained on antipsychotic and other psychotropic medications were randomized to supplemental EGCG or placebo. Study participants completed clinical assessments and blood draws to evaluate supplemental treatment effects on psychiatric symptoms and plasma inflammatory markers.

RESULTS

A total of 34 participants (17 EGCG, 17 placebo) were randomized and 25 participants (14 EGCG, 11 placebo) completed the study. Both treatment groups showed significant reductions in psychotic, depressive and anxiety symptoms from baseline to end of treatment. However, EGCG did not significantly affect psychiatric symptoms or inflammatory markers, as compared with placebo. Adverse effects were mild and comparable between groups.

CONCLUSION

There was no signal for a therapeutic effect of the green tea extract EGCG on psychiatric symptoms in this placebo-controlled pilot study.

Immune system gene dysregulation in autism and schizophrenia

Gene*environment interactions play critical roles in the emergence of autism and schizophrenia pathophysiology. In both disorders, recent genetic association studies have provided evidence for disease-linked variation in immune system genes and postmortem gene expression studies have shown extensive chronic immune abnormalities in brains of diseased subjects. Furthermore, peripheral biomarker studies revealed that both innate and adaptive immune systems are dysregulated. In both disorders symptoms of the disease correlate with the immune system dysfunction; yet, in autism this process appears to be chronic and sustained, while in schizophrenia it is exacerbated during acute episodes. Furthermore, since immune abnormalities endure into adulthood and anti-inflammatory agents appear to be beneficial, it is likely that these immune changes actively contribute to disease symptoms. Modeling these changes in animals provided further evidence that prenatal maternal immune activation alters neurodevelopment and leads to behavioral changes that are relevant for autism and schizophrenia. The converging evidence strongly argues that neurodevelopmental immune insults and genetic background critically interact and result in increased risk for either autism or schizophrenia. Further research in these areas may improve prenatal health screening in genetically at-risk families and may also lead to new preventive and/or therapeutic strategies.

Maternal immune activation alters behavior in adult offspring, with subtle changes in the cortical transcriptome and epigenome

Maternal immune activation during prenatal development, including treatment with the viral RNA mimic, polyriboinosinic-polyribocytidilic acid (poly IC), serves as a widely used animal model to induce behavioral deficits reminiscent of schizophrenia and related disease. Here, we report that massive cytokine activation after a single dose of poly IC in the prenatal period is associated with lasting working memory deficits in adult offspring. To explore whether dysregulated gene expression in cerebral cortex, contributes to cognitive dysfunction, we profiled the cortical transcriptome, and in addition, mapped the genome-wide distribution of trimethylated histone H3-lysine 4 (H3K4me3), an epigenetic mark sharply regulated at the 5' end of transcriptional units. However, deep sequencing-based H3K4me3 mapping and mRNA profiling by microarray did not reveal significant alterations in mature cerebral cortex after poly IC exposure at embryonic days E17.5 or E12.5. At a small set of genes (including suppressor of cytokine signaling Socs3), H3K4me3 was sensitive to activation of cytokine signaling in primary cultures from fetal forebrain but adult cortex of saline- and poly IC-exposed mice did not show significant differences. A limited set of transcription start sites (TSS), including Disrupted-in-Schizophrenia 1 (Disc1), a schizophrenia risk gene often implicated in gene-environment interaction models, showed altered H3K4me3 after prenatal poly IC but none of these differences survived after correcting for multiple comparisons. We conclude that prenatal poly IC is associated with cognitive deficits later in life, but without robust alterations in epigenetic regulation of gene expression in the cerebral cortex.

The Impact of Maternal High-Fat Diet Consumption on Neural Development and Behavior of Offspring

Maternal diet and metabolic state are important factors in determining the environment experienced during perinatal development. Epidemiological studies and evidence from animal models provide evidence that a mother's diet and metabolic condition are important in programming the neural circuitry that regulates behavior, resulting in a persistent impact on the offspring's behavior. Potential mechanisms by which maternal diet and metabolic profile influence the perinatal environment include placental dysfunction and increases in circulating factors such as inflammatory cytokines, nutrients (glucose and fatty acids) and hormones (insulin and leptin). Maternal obesity and high-fat diet (HFD) consumption exposure during development have been observed to increase the risk of developing serious mental health and behavioral disorders including anxiety, depression, attention deficit hyperactivity disorder and autism spectrum disorder. The increased risk of developing these behavioral disorders is postulated to be due to perturbations in the development of neural pathways that regulate behavior, including the serotonergic, dopaminergic and melanocortinergic systems. It is critical to examine the influence that a mother's nutrition and metabolic profile have on the developing offspring considering the current and alarmingly high prevalence of obesity and HFD consumption in pregnant women.