Genome-wide expression in veterans with schizophrenia further validates the immune hypothesis for schizophrenia

Whole transcriptome analysis reveals dysregulation of molecular networks in schizophrenia

To characterize the regulatory relationships between different types of transcripts and the altered molecular networks in schizophrenia (SCZ), we performed a whole transcriptome study by quantifying mRNAs, long noncoding RNAs (lncRNAs), miRNAs, and circular RNAs (circRNAs) in the same individuals simultaneously. A total of 807 dysregulated genes showed differential expression in SCZ cases compared with controls. Network-based analysis revealed dysregulation of molecular networks in SCZ. Finally, integration of the transcriptome data with published data identified promising SCZ candidate genes. Our study reveals that dysregulated molecular networks and regulatory relationships between different types of transcript may have a role in SCZ.

Patients with schizophrenia and bipolar disorder display a similar global gene expression signature in whole blood that reflects elevated proportion of immature neutrophil cells with association to lipid changes

Schizophrenia (SCZ) and bipolar disorder (BD) share clinical characteristics, genetic susceptibility, and immune alterations. We aimed to identify differential transcriptional patterns in peripheral blood cells of patients with SCZ or BD versus healthy controls (HC). We analyzed microarray-based global gene expression data in whole blood from a cohort of SCZ (N = 329), BD (N = 203) and HC (N = 189). In total, 65 genes were significantly differentially expressed in SCZ and 125 in BD, as compared to HC, with similar ratio of up- and downregulated genes in both disorders. Among the top differentially expressed genes, we found an innate immunity signature that was shared between SCZ and BD, consisting of a cluster of upregulated genes (e.g., OLFM4, ELANE, BPI and MPO) that indicate an increased fraction of immature neutrophils. Several of these genes displayed sex differences in the expression pattern, and post-hoc analysis demonstrated a positive correlation with triglyceride and a negative correlation with HDL cholesterol. We found that many of the downregulated genes in SCZ and BD were associated with smoking. These findings of neutrophil granulocyte-associated transcriptome signatures in both SCZ and BD point at altered innate immunity pathways with association to lipid changes and potential for clinical translation.

Chemokine Dysregulation and Neuroinflammation in Schizophrenia: A Systematic Review

Chemokines are known to be immunoregulatory proteins involved not only in lymphocyte chemotaxis to the site of inflammation, but also in neuromodulation, neurogenesis, and neurotransmission. Multiple lines of evidence suggest a peripheral proinflammatory state and neuroinflammation in at least a third of patients with schizophrenia. Therefore, chemokines can be active players in these processes. In this systematic review, we analyzed the available data on chemokine dysregulation in schizophrenia and the association of chemokines with neuroinflammation. It has been shown that there is a genetic association of chemokine and chemokine receptor gene polymorphisms in schizophrenia. Besides, the most reliable data confirmed by the results of meta-analyses showed an increase in CXCL8/IL-8, CCL2/MCP-1, CCL4/MIP-1β, CCL11/eotaxin-1 in the blood of patients with schizophrenia. An increase in CXCL8 has been found in cerebrospinal fluid, but other chemokines have been less well studied. Increased/decreased expression of genes of chemokine and their receptors have been found in different areas of the brain and peripheral immune cells. The peripheral proinflammatory state may influence the expression of chemokines since their expression is regulated by pro- and anti-inflammatory cytokines. Mouse models have shown an association of schizophrenia with dysregulation of the CX3CL1-CX3CR1 and CXCL12-CXCR4 axes. Altogether, dysregulation in chemokine expression may contribute to neuroinflammation in schizophrenia. In conclusion, this evidence indicates the involvement of chemokines in the neurobiological processes associated with schizophrenia.

Increased NLRP3 inflammasome expression in peripheral blood mononuclear cells of patients with schizophrenia: a case-control study

OBJECTIVE

This study aimed to evaluate the gene expression of the P2X purinoceptor 7 (P2X7R)- nod-like receptor pyrin domain-containing protein 3 (NLRP3) signal pathway in peripheral blood mononuclear cells (PBMCs) between schizophrenia (SCZ) patients and healthy controls (HC) to reveal its relationship with clinical variables.

METHODS

Thirty-two SCZ patients and 41 healthy controls were included in this study. The Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for the Assessment of Negative Symptoms (SANS), The Global Assessment of Functioning (GAF) scale and the Functioning Assessment Short Test (FAST) scales were applied. P2X7R, NLRP3, IL-1β and IL-18 gene expression levels were evaluated by real-time polymerase chain reaction in PBMCs.

RESULTS

NLRP3, P2RX7, IL-1β and IL-18 expression levels were significantly higher in PBMCs of SCZ patients than in HC subjects. Negative correlations were found between NLRP3 gene expression levels and GAF and FAST scales scores. There was a negative correlation between IL-18 expression levels and the GAF and FAST scales scores and a positive correlation with the SAPS scale scores.

CONCLUSIONS

Systemic inflammation is implicated in SCZ pathogenesis, according to our findings, which suggest that the NLRP3 pathway may be involved. The NLRP3 inflammasome may serve as a biomarker for SCZ, and its pharmacological regulation may be a promising treatment approach.Key pointsWe hypothesised that the NLRP3 pathway may contribute to the etiopathogenesis of schizophrenia.NLRP3, IL-1β and IL-18 mRNA levels were higher in patients with schizophrenia compared to healthy controls.Negative correlations were found between NLRP3 gene expression levels and GAF and FAST scales scores.There was a negative correlation between IL-18 expression levels and the GAF and FAST scales scores.The SAPS scale scores and IL-18 expression levels had a positive correlation.Given all these findings, it can be stated that NLRP3 inflammasome may play a role in the pathogenesis and symptoms of schizophrenia.

Variants of Th17 pathway-related genes influence brain morphometric changes and the risk of schizophrenia through epistatic interactions

OBJECTIVE

T helper 17 (Th17) pathway has been reported to be abnormal in schizophrenia; however, it is not known whether variation within genes of this pathway has any impact on schizophrenia. Herein, the impact of genetic variations and gene-gene interactions of Th17 pathway-related genes on the risk, psychopathology, and brain volume was examined in schizophrenia patients.

METHODS

Functional polymorphisms within interleukin 6 ( IL6 )(rs1800795 and rs1800797), IL10 (rs1800872 and rs1800896), IL17A (rs2275913 and rs8193036), IL22 (rs2227484 and rs2227485), IL23R (rs1884444), and IL27 (rs153109 and rs181206) genes were studied in 224 schizophrenia patients and 226 healthy controls. These variants were correlated with the brain morphometry, analyzed using MRI in a subset of patients ( n = 117) and controls ( n = 137).

RESULTS

Patients carrying CC genotype of rs2227484 of IL22 gene had significantly higher apathy total score [ F (1,183) = 5.60; P = 0.019; partial ɳ 2 = 0.030]. Significant epistatic interactions between IL6 (rs1800797) and IL17A (rs2275913) genes were observed in schizophrenia patients. GG genotype of rs2275913 of IL17A gene was associated with reduced right middle occipital gyrus volume in schizophrenia patients ( T = 4.56; P < 0.001).

CONCLUSION

Interactions between genes of Th17 pathway impact the risk for schizophrenia. The variants of Th17 pathway-related genes seem to have a determining effect on psychopathology and brain morphometric changes in schizophrenia.

Shedding light on the role of CX3CR1 in the pathogenesis of schizophrenia

Schizophrenia has a complex and heterogeneous molecular and clinical picture. Over the years of research on this disease, many factors have been suggested to contribute to its pathogenesis. Recently, the inflammatory processes have gained particular interest in the context of schizophrenia due to the increasing evidence from epidemiological, clinical and experimental studies. Within the immunological component, special attention has been brought to chemokines and their receptors. Among them, CX3C chemokine receptor 1 (CX3CR1), which belongs to the family of seven-transmembrane G protein-coupled receptors, and its cognate ligand (CX3CL1) constitute a unique system in the central nervous system. In the view of regulation of the brain homeostasis through immune response, as well as control of microglia reactivity, the CX3CL1–CX3CR1 system may represent an attractive target for further research and schizophrenia treatment. In the review, we described the general characteristics of the CX3CL1–CX3CR1 axis and the involvement of this signaling pathway in the physiological processes whose disruptions are reported to participate in mechanisms underlying schizophrenia. Furthermore, based on the available clinical and experimental data, we presented a guide to understanding the implication of the CX3CL1–CX3CR1 dysfunctions in the course of schizophrenia.

Differential levels of CHMP2B, LLPH, and SLC25A51 proteins in secondary renal amyloidosis

OBJECTIVES

Renal amyloidosis (RA) is a rare disease, typically manifested with proteinuria, nephrotic syndrome, and ultimately leads to renal failure. The present study aims to profile the proteomes of renal amyloidosis patient's serum and healthy controls, along with relative quantification to find out robust markers for RA.

METHODS

In this study, 12 RA patients and their corresponding age and gender-matched healthy controls were recruited from the Nephrology department of Max Super Specialty Hospital, New Delhi. We employed gel-based proteomic approach coupled with MALDI-TOF MS to compare protein expression patterns in RA patients and controls. Furthermore, validation of differential proteins (selected) was done using bio-layer interferometry.

RESULTS

Eleven proteins showed remarkably altered expression levels. Moreover, expression modulation of three proteins (LLPH, SLC25A51, and CHMP2B) was validated which corroborated with two-dimensional gel electrophoresis (2-DE) results showing significant upregulation (p < 0.05) in RA patients followed by ROC analysis which demonstrated the diagnostic potential of these proteins. A protein-protein master network was generated implicating the above identified proteins along with their interactors, fishing out the routes leading to amyloidosis.

CONCLUSION

This study indicates that the identified serum proteomic signatures could improve early diagnosis and lead to possible therapeutic targets in RA.