Epigenetic variability in conversion to psychosis: novel findings from an innovative longitudinal methylomic analysis

Epigenetic profile of the immune system associated with symptom severity and treatment response in schizophrenia

BACKGROUND

Environmental modification of genetic information (epigenetics) is often invoked to explain interindividual differences in the phenotype of schizophrenia. In clinical practice, such variability is most prominent in the symptom profile and the treatment response. Epigenetic regulation of immune function is of particular interest, given the therapeutic relevance of this mechanism in schizophrenia.

METHODS

We analyzed the DNA methylation data of immune-relevant genes in patients with schizophrenia whose disease duration was less than 3 years, with previous lifetime antipsychotic treatment of no more than 2 weeks total.

RESULTS

A total of 441 patients met the inclusion criteria. Core symptoms were consistently associated with 206 methylation positions, many of which had previously been implicated in inflammatory responses. Of these, 24 methylation positions were located either in regulatory regions or near the CpG islands of 20 genes, including the SRC gene, which is a key player in glutamatergic signalling. These symptom-associated immune genes were enriched in neuronal development functions, such as neuronal migration and glutamatergic synapse. Compared with using only clinical information (including scores on the Positive and Negative Syndrome Scale), integrating methylation data into the model significantly improved the predictive ability (as indicated by area under the curve) for response to 8 weeks of antipsychotic treatment.

LIMITATIONS

We focused on a small number of methylation probes (immune-centred search) and lacked nutritional data and direct brain-based measures.

CONCLUSION

Epigenetic modifications of the immune system are associated with symptom severity at onset and subsequent treatment response in schizophrenia.

Genome-wide DNA methylation analysis in families with multiple individuals diagnosed with schizophrenia and intellectual disability

OBJECTIVES

Schizophrenia (SZ) and intellectual disability (ID) are both included in the continuum of neurodevelopmental disorders (NDDs). DNA methylation is known to be important in the occurrence of NDDs. The family study is conducive to eliminate the effects of relative epigenetic backgrounds, and to screen for differentially methylated positions (DMPs) and regions (DMRs) that are truly associated with NDDs.

METHODS

Four monozygotic twin families were recruited, and both twin individuals suffered from NDDs (either SZ, ID, or SZ plus ID). Genome-wide methylation analysis was performed in all samples and each family. DMPs and DMRs between NDD patients and unaffected individuals were identified. Functional and pathway enrichment analyses were performed on the annotated genes.

RESULTS

Two significant DMPs annotated to CYP2E1 were found in all samples. In Family One, 1476 DMPs mapped to 880 genes, and 162 DMRs overlapping with 153 unique genes were recognised. Our results suggested that the altered methylation levels of FYN, STAT3, RAC1, and NR4A2 were associated with the development of SZ and ID. Neurodevelopment and the immune system may participate in the occurrence of SZ and ID.

CONCLUSIONS

Our findings suggested that DNA methylation participated in the development of NDDs by affecting neurodevelopment and the immune system.

Psychotic disorders as a framework for precision psychiatry

People with psychotic disorders can show marked interindividual variations in the onset of illness, responses to treatment and relapse, but they receive broadly similar clinical care. Precision psychiatry is an approach that aims to stratify people with a given disorder according to different clinical outcomes and tailor treatment to their individual needs. At present, interindividual differences in outcomes of psychotic disorders are difficult to predict on the basis of clinical assessment alone. Therefore, current research in psychosis seeks to build models that predict outcomes by integrating clinical information with a range of biological measures. Here, we review recent progress in the application of precision psychiatry to psychotic disorders and consider the challenges associated with implementing this approach in clinical practice.

Homeorhesis: envisaging the logic of life trajectories in molecular research on trauma and its effects

What sets someone on a life trajectory? This question is at the heart of studies of 21st-century neurosciences that build on scientific models developed over the last 150 years that attempt to link psychopathology risk and human development. Historically, this research has documented persistent effects of singular, negative life experiences on people's subsequent development. More recently, studies have documented neuromolecular effects of early life adversity on life trajectories, resulting in models that frame lives as disproportionately affected by early negative experiences. This view is dominant, despite little evidence of the stability of the presumably early-developed molecular traits and their potential effects on phenotypes. We argue that in the context of gaps in knowledge and the need for scientists to reason across molecular and phenotypic scales, as well as time spans that can extend beyond an individual's life, specific interpretative frameworks shape the ways in which individual scientific findings are assessed. In the process, scientific reasoning oscillates between understandings of cellular homeostasis and organisms' homeorhesis, or life trajectory. Biologist and historian François Jacob described this framework as the "attitude" that researchers bring to bear on their "objects" of study. Through an analysis of, first, historical and contemporary scientific literature and then ethnographic research with neuroscientists, we consider how early life trauma came to be associated with specific psychological and neurobiological effects grounded in understandings of life trajectories. We conclude with a consideration of the conceptual, ontological, and ethical implications of interpreting life trajectories as the result of the persistence of long-embodied biological traits, persistent life environments, or both.

Methyltransferase Setdb1 Promotes Osteoblast Proliferation by Epigenetically Silencing Macrod2 with the Assistance of Atf7ip

Bone loss caused by mechanical unloading is a threat to prolonged space flight and human health. Epigenetic modifications play a crucial role in varied biological processes, but the mechanism of histone modification on unloading-induced bone loss has rarely been studied. Here, we discovered for the first time that the methyltransferase Setdb1 was downregulated under the mechanical unloading both in vitro and in vivo so as to attenuate osteoblast proliferation. Furthermore, we found these interesting processes depended on the repression of Macrod2 expression triggered by Setdb1 catalyzing the formation of H3K9me3 in the promoter region. Mechanically, we revealed that Macrod2 was upregulated under mechanical unloading and suppressed osteoblast proliferation through the GSK-3β/β-catenin signaling pathway. Moreover, Atf7ip cooperatively contributed to osteoblast proliferation by changing the localization of Setdb1 under mechanical loading. In summary, this research elucidated the role of the Atf7ip/Setdb1/Macrod2 axis in osteoblast proliferation under mechanical unloading for the first time, which can be a potential protective strategy against unloading-induced bone loss.

Early Detection and Prevention of Schizophrenic Psychosis-A Review

Psychotic disorders often run a chronic course and are associated with a considerable emotional and social impact for patients and their relatives. Therefore, early recognition, combined with the possibility of preventive intervention, is urgently warranted since the duration of untreated psychosis (DUP) significantly determines the further course of the disease. In addition to established diagnostic tools, neurobiological factors in the development of schizophrenic psychoses are increasingly being investigated. It is shown that numerous molecular alterations already exist before the clinical onset of the disease. As schizophrenic psychoses are not elicited by a single mutation in the deoxyribonucleic acid (DNA) sequence, epigenetics likely constitute the missing link between environmental influences and disease development and could potentially serve as a biomarker. The results from transcriptomic and proteomic studies point to a dysregulated immune system, likely evoked by epigenetic alterations. Despite the increasing knowledge of the neurobiological mechanisms involved in the development of psychotic disorders, further research efforts with large population-based study designs are needed to identify suitable biomarkers. In conclusion, a combination of blood examinations, functional imaging techniques, electroencephalography (EEG) investigations and polygenic risk scores should be considered as the basis for predicting how subjects will transition into manifest psychosis.

Genetic liability in individuals at ultra-high risk of psychosis: A comparison study of 9 psychiatric traits

Individuals at ultra-high risk (UHR) of psychosis are characterised by the emergence of attenuated psychotic symptoms and deterioration in functioning. In view of the high non-psychotic comorbidity and low rates of transition to psychosis, the specificity of the UHR status has been called into question. This study aims to (i) investigate if the UHR construct is associated with the genetic liability of schizophrenia or other psychiatric conditions; (ii) examine the ability of polygenic risk scores (PRS) to discriminate healthy controls from UHR, remission and conversion status. PRS was calculated for 210 youths (nUHR = 102, nControl = 108) recruited as part of the Longitudinal Youth at Risk Study (LYRIKS) using nine psychiatric traits derived from twelve large-scale psychiatric genome-wide association studies as discovery datasets. PRS was also examined to discriminate UHR-Healthy control status, and healthy controls from UHR remission and conversion status. Result indicated that schizophrenia PRS appears to best index the genetic liability of UHR, while trend level associations were observed for depression and cross-disorder PRS. Schizophrenia PRS discriminated healthy controls from UHR (R2 = 7.9%, p = 2.59 x 10-3, OR = 1.82), healthy controls from non-remitters (R2 = 8.1%, p = 4.90 x 10-4, OR = 1.90), and converters (R2 = 7.6%, p = 1.61 x 10-3, OR = 1.82), with modest predictive ability. A trend gradient increase in schizophrenia PRS was observed across categories. The association between schizophrenia PRS and UHR status supports the hypothesis that the schizophrenia polygenic liability indexes the risk for developing psychosis.

Cross-Sectional Survey of Mental Health Risk Factors and Comparison of the Monoamine oxidase A Gene DNA Methylation Level in Different Mental Health Conditions among Oilfield Workers in Xinjiang, China

The incidence of psychological problems among occupational groups is becoming increasingly more serious, and adverse psychological conditions will seriously affect the working ability of occupational groups and harm the health of their bodies. This study adopted a multi-stage stratified cluster sampling method to conduct a cross-sectional survey on the mental health of 3631 oil workers in Karamay, Xinjiang from March 2017 to June 2018. The mental health status of oil workers was evaluated using the Symptom Checklist-90, and mental health risk factors were evaluated. The correlation between the monoamine oxidase A (MAOA) gene and mental health was analyzed, and the DNA methylation level of the MAOA gene was compared between the normal group and the abnormal group. The results show the incidence of mental health problems among oil workers according to differences in age, nationality, type of work, length of service, professional title, shift work, and marital status. The evaluation of mental health risk factors revealed that shift work, occupational stress, and high payment/low return affect mental health. The somatization scores of different genotypes of rs6323 in the MAOA gene were statistically significant (p < 0.05), suggesting that the somatization scores of different genotypes of rs6323 were different. According to the average rank, the TT genotype group had the highest score, followed by the GT genotype group, and the GG genotype group had the lowest score. The level of DNA methylation in the abnormal group was lower than that in the normal group (p < 0.05). The results suggested that occupational mental health can be enhanced by improving shift work, reducing stress, and balancing effort and reward. This preliminary investigation suggests that methylation status can affect mental health, indicating that methylation level may be a predictor of mental health status.

Childhood-Onset Schizophrenia: A Systematic Overview of Its Genetic Heterogeneity From Classical Studies to the Genomic Era

Childhood-onset schizophrenia (COS), a very rare and severe chronic psychiatric condition, is defined by an onset of positive symptoms (delusions, hallucinations and disorganized speech or behavior) before the age of 13. COS is associated with other neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention deficit and hyperactivity disorder. Copy number variations (CNVs) represent well documented neurodevelopmental disorder risk factors and, recently, de novo single nucleotide variations (SNVs) in genes involved in brain development have also been implicated in the complex genetic architecture of COS. Here, we aim to review the genetic changes (CNVs and SNVs) reported for COS, going from previous studies to the whole genome sequencing era. We carried out a systematic review search in PubMed using the keywords “childhood(early)-onset schizophrenia(psychosis)” and “genetic(s) or gene(s) or genomic(s)” without language and date limitations. The main inclusion criteria are COS (onset before 13 years old) and all changes/variations at the DNA level (CNVs or SNVs). Thirty-six studies out of 205 met the inclusion criteria. Cytogenetic abnormalities (n = 72, including 66 CNVs) were identified in 16 autosomes and 2 sex chromosomes (X, Y), some with a higher frequency and clinical significance than others (e.g., 2p16.3, 3q29, 15q13.3, 22q11.21 deletions; 2p25.3, 3p25.3 and 16p11.2 duplications). Thirty-one single nucleotide mutations in genes principally involved in brain development and/or function have been found in 12 autosomes and one sex chromosome (X). We also describe five SNVs in X-linked genes inherited from a healthy mother, arguing for the X-linked recessive inheritance hypothesis. Moreover, ATP1A3 (19q13.2) is the only gene carrying more than one SNV in more than one patient, making it a strong candidate for COS. Mutations were distributed in various chromosomes illustrating the genetic heterogeneity of COS. More than 90% of CNVs involved in COS are also involved in ASD, supporting the idea that there may be genetic overlap between these disorders. Different mutations associated with COS are probably still unknown, and pathogenesis might also be explained by the association of different genetic variations (two or more CNVs or CNVs and SNVs) as well as association with early acquired brain lesions such as infection, hypoxia, or early childhood trauma.

Do cognitive and neuropsychological functioning deficits coincide with hippocampal alteration during first-psychotic episode?

BACKGROUND

Numerous studies shown that structural hippocampal alterations are present in subjects at high risk of developing psychosis or schizophrenia. These findings indicate that in a subset of patients undergoing first-psychosis episode (FPE), hippocampal volume alterations are accompanied by associated cognitive and neuropsychological deficits. The combination of psychological deficits and neuroanatomical alterations, in turn, appears to increase treatment complexity and worsen clinical outcomes.

OBJECTIVE

We aim to determine whether cognitive and neuropsychological functioning deficits precede or follow hippocampal alterations during early onset psychosis.

METHODS

This cross-sectional study describes 3 case-studies of adolescent subjects, ages 16-17, admitted at the child and adolescent inpatient psychiatric unit in lieu of first psychotic episode. We conducted detailed structured clinical psychiatric interviews, anatomical-structural magnetic resonance imaging (MRI), sleep-deprived electroencephalogram (EEG) recordings, laboratory testing, and a comprehensive battery of psychological testing to better understand their clinical pictures.

RESULTS

Psychological testing in each patient demonstrated the presence of low to borderline intellectual functioning coupled with neuropsychological deficits in different psychiatric domains. Interestingly, these changes coincided with structural MRI alterations in the hippocampal area.

CONCLUSIONS

Our case report adds to the armamentarium of literature signifying that radiologically detectable alterations of the hippocampus may occur either concomitantly or closely following the development of early cognitive deficits in patients with FPE.

A systematic review of genome-wide association studies of antipsychotic response

Clinical symptom response to antipsychotic medications is highly variable. Genome-wide association studies (GWAS) provide a 'hypothesis-free' method of interrogating the genome for biomarkers of antipsychotic response. We performed a systematic review of GWAS findings for antipsychotic efficacy or effectiveness. 14 studies met our inclusion criteria, ten of which examined antipsychotic response using quantitative rating scales to measure symptom improvement. 15 genome-wide significant loci were identified, seven of which were replicated in other antipsychotic GWAS publications: CNTNAP5, GRID2, GRM7, 8q24 (KCNK9), PCDH7, SLC1A1 and TNIK. Notably, four replicated loci are involved in glutamatergic pathways. Additional validation and evaluation of the biological significance of these markers is warranted. These markers should also be evaluated for clinical utility, especially in the context of other validated pharmacogenomic variants (e.g., CYP450 genes). These findings may generate new avenues for development of novel antipsychotic treatments.

Epigenetic outlier profiles in depression: A genome-wide DNA methylation analysis of monozygotic twins

Recent discoveries highlight the importance of stochastic epigenetic changes, as indexed by epigenetic outlier DNA methylation signatures, as a valuable tool to understand aberrant cell function and subsequent human pathology. There is evidence of such changes in different complex disorders as diverse as cancer, obesity and, to a lesser extent, depression. The current study was aimed at identifying outlying DNA methylation signatures of depressive psychopathology. Here, genome-wide DNA methylation levels were measured (by means of Illumina Infinium HumanMethylation450 Beadchip) in peripheral blood of thirty-four monozygotic twins informative for depressive psychopathology (lifetime DSM-IV diagnoses). This dataset was explored to identify outlying epigenetic signatures of depression, operationalized as extreme hyper- or hypo-methylation in affected co-twins from discordant pairs that is not observed across the rest of the study sample. After adjusting for blood cell count, there were thirteen CpG sites across which depressed co-twins from the discordant pairs exhibited outlying DNA methylation signatures. None of them exhibited a methylation outlier profile in the concordant and healthy pairs, and some of these loci spanned genes previously associated with neuropsychiatric phenotypes, such as GHSR and KCNQ1. This exploratory study provides preliminary proof-of-concept validation that epigenetic outlier profiles derived from genome-wide DNA methylation data may be related to depression risk.