Eduardo Sauerbronn Gouvea

Effects of Risperidone on Cytokine Profile in Drug-Naïve First-Episode Psychosis

Background: There is robust evidence that schizophrenia is characterized by immune-inflammatory abnormalities, including variations on cytokine levels. The results of previous studies, however, are heterogeneous due to several confounding factors, such as the effects of antipsychotic drugs. Therefore, research on drug-naïve first-episode psychosis (FEP) patients is essential to elucidate the role of immune processes in that disorder. Methods: The aim of this study is to compare cytokine levels (IL-2, IL-10, IL-4, IL-6, IFN-γ, TNF-α, and IL-17) in drug-naïve FEP patients both before and after treatment with risperidone for 10 weeks, and to investigate possible associations between cytokine levels and clinical responses to treatment and presence of depressive symptoms. It this study, we included 55 drug-naïve FEP patients who had repeated measurements of cytokine levels and 57 healthy controls. Results: We found that FEP patients had significantly higher IL-6, IL-10 and TNF-α levels than healthy controls. After risperidone treatment, these three cytokines and additionally IL-4 decreased significantly. No significant difference was found between the post-treatment cytokine levels in FEP patients and in healthy controls, suggesting that these alterations in cytokine profiles are a state marker of FEP. No significant association was found between risperidone-induced changes in cytokines and the clinical response to treatment or the presence of depression. There was a significant inverse association between the risperidone-induced changes in IL-10 and the negative symptoms. Conclusions: In conclusion, our results show a specific cytokine profile in FEP patients (monocytic and regulatory T-cell activation) and suggest immunoregulatory effects of risperidone treatment, characterized by suppressant effects on monocytic, Th2, and T-regulatory functions.

Changes in gene expression and methylation in the blood of patients with first-episode psychosis

Schizophrenia is a severe mental health disorder with high heritability. The investigation of individuals during their first-episode psychosis (FEP), before the progression of psychotic disorders and especially before treatment with antipsychotic medications, is particularly helpful for understanding this complex disease and for the identification of potential biomarkers. In this study, we compared the expression of genes that are involved in neurotransmission and neurodevelopment of antipsychotic-naive FEP in the peripheral blood of patients (n=51) and healthy controls (n=51). In addition, we investigated the differentially expressed genes with respect to a) DNA methylation, b) the correlation between gene expression and clinical variables (PANSS), and c) gene expression changes after risperidone treatment. Expression levels of 11 genes were quantified with SYBR Green. For methylation analysis, bisulfite sequencing was performed. A significant decrease in GCH1 mRNA levels was observed in FEP patients relative to controls. Also, when we compare the FEP patients after risperidone treatment with controls, this difference remains significant, and no significant differences were observed in GCH1 mRNA levels when comparing patients before and after risperidone treatment. Additionally, although the differences were non-significant after Bonferroni correction, the expression of GCH1 seemed to be correlated with PANSS scores, and the GCH1 promoter region was more methylated in FEP than in controls, thus corroborating the results obtained at the mRNA level. Few studies have been conducted on GCH1, and future studies are needed to clarify its potential role in the progression of schizophrenia.

Depression, Cytokine, and Cytokine by Treatment Interactions Modulate Gene Expression in Antipsychotic Naive First Episode Psychosis

In schizophrenia, genetic and environmental factors affect neurodevelopment and neuroprogressive trajectory. Altered expression of neuro-immune genes and increased levels of cytokines are observed, especially in patients with comorbid depression. However, it remains unclear whether circulating levels of cytokines and expression of these genes are associated, and how antipsychotic treatments impact this association. Relationships between messenger RNA (mRNA) expression of 11 schizophrenia-related genes and circulating levels of cytokines (interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-α) were analyzed in 174 antipsychotic naïve first episode psychosis (FEP) and in 77 healthy controls. A subgroup of 72 patients was reassessed after treatment with risperidone. FEP patients were divided into those with and without depression. FEP patients with depression showed increased COMT expression and decreased NDEL1 expression. Increased IL-6 was associated with lowered AKT1 and DROSHA expression, while increased IL-10 was associated with increased NDEL1, DISC1, and MBP expression. IL-6 levels significantly increased the risperidone-induced expression of AKT1, DICER1, DROSHA, and COMT mRNA. The differential mRNA gene expression in FEP is largely associated with increased cytokine levels. While increased IL-6 may downregulate AKT-mediated cellular functions and dysregulate genes involved in microRNA (miRNA) machinery, increased IL-10 has neuroprotective properties. Increased IL-6 levels may prime the expression of genes (AKT1, DICER1, DROSHA, and COMT) in response to risperidone, suggesting that cytokine × treatment × gene interactions may improve cell function profiles. FEP patients with depression show a different gene expression profile reinforcing the theory that depression in FEP is a different phenotype.

Gene expression alterations related to mania and psychosis in peripheral blood of patients with a first episode of psychosis.

Psychotic disorders affect ~3% of the general population and are among the most severe forms of mental diseases. In early stages of psychosis, clinical aspects may be difficult to distinguish from one another. Undifferentiated psychopathology at the first-episode of psychosis (FEP) highlights the need for biomarkers that can improve and refine differential diagnosis. We investigated gene expression differences between patients with FEP–schizophrenia spectrum (SCZ; N=53) or FEP–Mania (BD; N=16) and healthy controls (N=73). We also verified whether gene expression was correlated to severity of psychotic, manic, depressive symptoms and/or functional impairment. All participants were antipsychotic-naive. After the psychiatric interview, blood samples were collected and the expression of 12 psychotic-disorder-related genes was evaluated by quantitative PCR. AKT1 and DICER1 expression levels were higher in BD patients compared with that in SCZ patients and healthy controls, suggesting that expression of these genes is associated more specifically to manic features. Furthermore, MBP and NDEL1 expression levels were higher in SCZ and BD patients than in healthy controls, indicating that these genes are psychosis related (independent of diagnosis). No correlation was found between gene expression and severity of symptoms or functional impairment. Our findings suggest that genes related to neurodevelopment are altered in psychotic disorders, and some might support the differential diagnosis between schizophrenia and bipolar disorder, with a potential impact on the treatment of these disorders.

Increased expression of NDEL1 and MBP genes in the peripheral blood of antipsychotic-naïve patients with first-episode psychosis

Schizophrenia is a multifactorial neurodevelopmental disorder with high heritability. First-episode psychosis (FEP) is a critical period for determining the disease prognosis and is especially helpful for identifying potential biomarkers associated with the onset and progression of the disorder. We investigated the mRNA expression of 12 schizophrenia-related genes in the blood of antipsychotic-naïve FEP patients (N=73) and healthy controls (N=73). To evaluate the influences of antipsychotic treatment and progression of the disorder, we compared the gene expression within patients before and after two months of treatment with risperidone (N=64). We observed a significantly increased myelin basic protein (MBP) and nuclear distribution protein nudE-like 1 (NDEL1) mRNA levels in FEP patients compared with controls. Comparing FEP before and after risperidone treatment, no significant differences were identified; however; a trend of relatively low NDEL1 expression was observed after risperidone treatment. Animals chronically treated with saline or risperidone exhibited no significant change in Ndel1 expression levels in the blood or the prefrontal cortex (PFC), suggesting that the trend of low NDEL1 expression observed in FEP patients after treatment is likely due to factors other than risperidone treatment (i.e., disease progression). In addition to the recognized association with schizophrenia, MBP and NDEL1 gene products also play an essential role in the functions that are deregulated in schizophrenia, such as neurodevelopment. Our data strengthen the importance of these biological processes in psychotic disorders, indicating that these changes can be detected peripherally and potentially represent putative novel blood biomarkers of susceptibility and disorder progression.

Accessing Gene Expression in Treatment-Resistant Schizophrenia

Schizophrenia (SCZ) is a mental disorder arising from a complex interaction of genetic and environmental factors. It has been suggested that treatment-resistant schizophrenia (TRS) is a distinct, more severe, and homogenous subgroup of schizophrenia that could present specific biological markers. Our aim was to characterize expression of target genes in blood of TRS patients compared with non-TRS (NTRS) patients and healthy controls (HC). TRS has been defined using failure to respond to two previous antipsychotic trials. We hypothesized that genes involved in neurodevelopment, myelination, neuroplasticity, neurotransmission, and miRNA processing could be involved in treatment resistance; then, we investigated 13 genes related to those processes in 256 subjects, being 94 healthy controls and 162 schizophrenia patients treated with antipsychotics. Of those, 78 were TRS patients and 84 were NTRS patients. Peripheral blood samples were collected from all subjects and RNA was isolated. Gene expression analysis was performed using the TaqMan low-density array (TLDA) technology. To verify the influence of expression quantitative trait loci (eQTLs), we evaluated single-nucleotide polymorphism (SNP) of all genes using data from GTEx Project. SNP genotypes were obtained from HumanOmniExpress BeadChip. We did not detect gene expression differences between TRS and NTRS subjects, indicating candidate genes specific to treatment resistance. We detected an upregulation of CNR1 and UFD1L gene expression in patients (TRS and NTRS groups) when compared to controls, that may be associated with the release of neurotransmitters, which can influence neuronal plasticity, or with a stress response-activating protein degradation. DICER1 and AKT1 expression increased slightly across the groups and could differentiate only the extreme opposite groups, HC and TRS. Both genes act in heterogeneous pathways, such as cell signaling and miRNA processing, and seem to have an increased demand in the TRS group. We did not detect any eQTLs in our sample that could explain differences in mRNA levels, suggesting a possible regulation by other mechanism, not driven by genotypes. Our data strengthen the importance of several biological pathways involved in the schizophrenia refractoriness and severity, adding knowledge to develop more effective treatments in the future.

The role of the CNR1 gene in schizophrenia: a systematic review including unpublished data.

Objective: Schizophrenia is a multifactorial disorder. It is known that a combination of extensive multiple common alleles may be involved in its etiology, each contributing with a small to moderate effect, and, possibly, some rare alleles with a much larger effect size. We aimed to perform a systematic review of association studies between schizophrenia (and its subphenotypes) and polymorphisms in the CNR1 gene, which encodes cannabinoid receptors classically implicated in schizophrenia pathophysiology, as well as to present unpublished results of an association study in a Brazilian population. Methods: Two reviewers independently searched for eligible studies and extracted outcome data using a structured form. Papers were retrieved from PubMed and ISI Web of Knowledge using the search term schizophrenia in combination with CNR1 or CB1 or cannabinoid receptor. Twenty-four articles met our inclusion criteria. We additionally present data from a study of our own comparing 182 patients with schizophrenia and 244 healthy controls. Results: No consistent evidence is demonstrated. Conclusion: Some seemingly positive association studies stress the need for further investigations of the possible role of endocannabinoid genetics in schizophrenia.

Polygenic risk score analyses of symptoms and treatment response in an antipsychotic-naive first episode of psychosis cohort

In this study, we aimed to test if the schizophrenia (SCZ) polygenic risk score (PRS) was associated with clinical symptoms in (a) the first episode of psychosis pre-treatment (FEP), (b) at nine weeks after initiation of risperidone treatment (FEP-9W) and (c) with the response to risperidone. We performed a detailed clinical assessment of 60 FEP patients who were antipsychotic-naive and, again, after nine weeks of standardized treatment with risperidone. After blood collection and DNA isolation, the samples were genotyped using the Illumina PsychArrayChip and then imputed. To calculate PRS, we used the latest available GWAS summary statistics from the Psychiatric Genomics Consortium wave-2 SCZ group as a training set. We used Poisson regression to test association between PRS and clinical measurements correcting for the four principal components (genotyping). We considered a p-value < 0.0014 (Bonferroni correction) as significant. First, we verified that the schizophrenia PRS was also able to distinguish cases from controls in this south-eastern Brazilian sample, with a similar variance explained to that seen in Northern European populations. In addition, within-cases analyses, we found that PRS is significantly correlated with baseline (pre-treatment) symptoms, as measured by lower clinical global assessment of functioning (−GAF), higher depressive symptoms and higher scores on a derived excitement factor. After standardized treatment for nine weeks, the correlation with GAF and the excitement factor disappeared while depressive symptoms became negatively associated with PRS. We conclude that drug (and other treatments) may confound attempts to understand the aetiological influence on symptomatology of polygenic risk scores. These results highlight the importance of studying schizophrenia, and other disorders, pre-treatment to understand the relationship between polygenic risk and phenotypic features.

Gene Expression Alterations Related To Mania And Psychotic Symptoms In Peripheral Blood of Patients with A First Episode of Psychosis

Background Psychotic disorders, such as schizophrenia and bipolar disorder, affect approximately 3% of the general population. The symptoms include hallucinations, delusional beliefs, severe mood variations, and cognitive impairment. However, these clinical aspects may be difficult to distinguish from one another, mainly during the early stages of psychosis. The first-episode psychosis (FEP) is a critical period given that brain abnormalities and cognitive deficits are already present and progress faster and more aggressively in the first years of the disorder. We investigated differences in the mRNA levels of 12 genes among individuals with FEP of schizophrenia spectrum disorder (FEP-S; N=53), FEP with mania (FEP-M; N=16), and healthy controls (N=73). We also verified whether gene expression is correlated to clinical features, including functional impairment and severity of psychotic, manic, and depressive symptoms. The study aims are to differentiate FEP-M and FEP-S, improving early diagnosis and adequate intervention. Methods Antipsychotic-naive FEP patients (N = 69) were recruited from a psychiatric emergency unit in Sao Paulo, Brazil. Trained psychiatrists established the diagnosis of a psychotic disorder and patients were assessed at baseline and followed up for at least two months. At the end of follow-up, patients with a schizophrenia or schizophreniform disorder diagnosis were classified as FEP-S (N = 53) and patients who met bipolar disorder (with psychotic symptoms) diagnostic criteria were classified as FEP-M (N = 16). Healthy controls were age- and gender-matched with no current or previous diagnosis of a psychiatric disease or family history of a psychotic disorder (N = 73). A total of 5 mL of whole blood was collected in PAXgene® RNA tubes and RNA was isolated with PAXgene Blood RNA kit. Approximately 400 ng of each RNA sample was reverse-transcribed. The expression of 12 psychotic-disorder-related genes was evaluated by quantitative PCR. Gene expression was quantified using the relative threshold method (Crt) with the geometric mean (GM) between ACTB and GAPDH as the endogenous control. Results AKT1 and DICER1 expression levels were higher in FEP-M patients compared to that in FEP-S patients and healthy controls, suggesting that expression of these genes is associated more specifically to manic features. DICER1 expression was positively correlated to the PANSS (positive and negative syndrome scale) excitement dimension and YMRS (young mania rating scale) total score. Furthermore, MBP and NDEL1 expression levels were higher in FEP-S and FEP-M patients than in healthy controls, indicating that these genes are psychosis-related (independent of diagnosis). Discussion To our knowledge, this is the first study that compares gene expression in antipsychotic-naive FEP-M and FEP-S, suggesting potential diagnostic specificities. Based on an integrated model, we propose that MBP and NDEL1 are upregulated in FEP-S and FEP-M patients, who all exhibit psychotic symptoms. Moreover, two other genes, AKT1 and DICER1, were upregulated in FEP-M patients only, indicating that these genes could be related to mania, independently of psychotic symptoms. Although further validation is needed, our findings suggest that genes related to neuronal development are altered in psychotic disorders, and some of them might support the differential diagnosis between schizophrenia and bipolar disorder in the near future, which in turn could have an impact on the treatment of these disorders.