The role of genes affected by human evolution marker GNA13 in schizophrenia

Modified Electroconvulsive Therapy Normalizes Plasma GNA13 Following Schizophrenic Relapse

OBJECTIVE

GNA13 is an important member of the G protein family, and its coding gene GNA13 has been identified as one of the risk genes for schizophrenia (SCZ). This study aimed to investigate the relationship between GNA13 levels and the clinical symptoms of SCZ following treatment with modified electroconvulsive therapy (MECT).

METHODS

This study recruited 82 SCZ patients and 86 healthy controls (HCs). Each SCZ patient received 6 sessions of MECT. The Positive and Negative Syndrome Scale (PANSS) was used to assess SCZ symptom severity. Plasma levels of GNA13 were measured by enzyme-linked immunosorbent assay.

RESULTS

Pretreatment, SCZ patients had a higher GNA13 level than HC (t = 8.199, P < 0.001). MECT reduced the GNA13 level significantly (t = 11.13, P < 0.001) and normalized the difference between SCZ and HC (t = 0.219, P = 0.827). After treatment, the downregulation of GNA13 (ΔGNA13) was negatively correlated with the positive symptoms score reduction rate (ΔP) (r = -0.379, P = 0.027) and positively correlated with the negative score reduction rate (ΔN) (r = 0.480, P = 0.004) in females. In both males and females, the receiver operating characteristic curve revealed that the pretreatment GNA13 level could help differentiate SCZ from HC (male: area under the curve = 0.792, P < 0.001; female: area under the curve = 0.814, P < 0.001).

CONCLUSION

The reduced expression of GNA13 after MECT may be related to the exhibition of both negative and positive symptoms of SCZ in female patients.

Zmym4 is required for early cranial gene expression and craniofacial cartilage formation

Introduction: The Six1 transcription factor plays important roles in the development of cranial sensory organs, and point mutations underlie craniofacial birth defects. Because Six1's transcriptional activity can be modulated by interacting proteins, we previously screened for candidate interactors and identified zinc-finger MYM-containing protein 4 (Zmym4) by its inclusion of a few domains with a bona fide cofactor, Sine oculis binding protein (Sobp). Although Zmym4 has been implicated in regulating early brain development and certain cancers, its role in craniofacial development has not previously been described. Methods: We used co-immunoprecipitation and luciferase-reporter assays in cultured cells to test interactions between Zmym4 and Six1. We used knock-down and overexpression of Zmym4 in embryos to test for its effects on early ectodermal gene expression, neural crest migration and craniofacial cartilage formation. Results: We found no evidence that Zmym4 physically or transcriptionally interacts with Six1 in cultured cells. Nonetheless, knockdown of endogenous Zmym4 in embryos resulted in altered early cranial gene expression, including those expressed in the neural border, neural plate, neural crest and preplacodal ectoderm. Experimentally increasing Zmym4 levels had minor effects on neural border or neural plate genes, but altered the expression of neural crest and preplacodal genes. At larval stages, genes expressed in the otic vesicle and branchial arches showed reduced expression in Zmym4 morphants. Although we did not detect defects in neural crest migration into the branchial arches, loss of Zmym4 resulted in aberrant morphology of several craniofacial cartilages. Discussion: Although Zmym4 does not appear to function as a Six1 transcriptional cofactor, it plays an important role in regulating the expression of embryonic cranial genes in tissues critical for normal craniofacial development.

Translatable pathways classification (TransPath-C) for inferring processes germane to human biology from animal studies data: example application in neurobiology

How to translate insights gained from studies in one organismal species for what is most likely to be germane in another species, such as from mice to humans, is a ubiquitous challenge in basic biology as well as biomedicine. This is an especially difficult problem when there are few molecular features that are obviously important in both species for a given phenotype of interest. Neuropathologies are a prominent realm of this complication. Schizophrenia is complex psychiatric disorder that affects 1% of the population. Many genetic factors have been proposed to drive the development of schizophrenia, and the 22q11 microdeletion (MD) syndrome has been shown to dramatically increase this risk. Due to heterogeneity of presentation of symptoms, diagnosis and formulation of treatment options for patients can often be delayed, and there is an urgent need for novel therapeutics directed toward the treatment of schizophrenia. Here, we present a novel computational approach, Translational Pathways Classification (TransPath-C), that can be used to identify shared pathway dysregulation between mouse models and human schizophrenia cohorts. This method uses variation of pathway activation in the mouse model to predict both mouse and human disease phenotype. Analysis of shared dysregulated pathways called out by both the mouse and human classifiers of TransPath-C can identify pathways that can be targeted in both preclinical and human cohorts of schizophrenia. In application to the 22q11 MD mouse model, our findings suggest that PAR1 pathway activation found upregulated in this mouse phenotype is germane for the corresponding human schizophrenia cohort such that inhibition of PAR1 may offer a novel therapeutic target.

Analysis of whole exome sequencing in severe mental illness hints at selection of brain development and immune related genes

Evolutionary trends may underlie some aspects of the risk for common, non-communicable disorders, including psychiatric disease. We analyzed whole exome sequencing data from 80 unique individuals from India coming from families with two or more individuals with severe mental illness. We used Population Branch Statistics (PBS) to identify variants and genes under positive selection and identified 74 genes as candidates for positive selection. Of these, 20 were previously associated with Schizophrenia, Alzheimer’s disease and cognitive abilities in genome wide association studies. We then checked whether any of these 74 genes were involved in common biological pathways or related to specific cellular or molecular functions. We found that immune related pathways and functions related to innate immunity such as antigen binding were over-represented. We also evaluated for the presence of Neanderthal introgressed segments in these genes and found Neanderthal introgression in a single gene out of the 74 candidate genes. However, the introgression pattern indicates the region is unlikely to be the source for selection. Our findings hint at how selection pressures in individuals from families with a history of severe mental illness may diverge from the general population. Further, it also provides insights into the genetic architecture of severe mental illness, such as schizophrenia and its link to immune factors.