Association between FKBP5 and CRHR1 genes with suicidal behavior: A systematic review

Are we Using the Right Evidence to Inform Suicide Prevention in Low- and Middle-Income Countries? An Umbrella Review

OBJECTIVE

Suicide disproportionately affects low- and middle-income countries and evidence regarding prevention approaches developed in high income countries may not be applicable in these settings. We conducted an umbrella review to assess whether the conclusions of suicide prevention systematic reviews accurately reflect the studies contained within those reviews in terms of setting generalizability.

METHODS

We conducted database searches in PubMed/Medline, Embase, PsycInfo, PsychExtra, OVID global health, and LILACS/BECS. We included systematic reviews with the outcome of suicide, including bereavement studies where suicide death was also the exposure.

RESULTS

Out of the 147 reviews assessed, we found that over 80% of systematic reviews on suicide deaths do not provide an accurate summary of review findings with relation to geographic relevance and ultimately generalizability.

CONCLUSION

Systematic reviews are often the resource used by practitioners and policymakers to guide services. Misleading reviews can detrimentally impact suicide prevention efforts in LMICs. We call for systematic reviewers to be responsible when generalizing the findings of their reviews particularly in the abstracts.

Biomarker-Guided Tailored Therapy in Major Depression

This chapter provides a comprehensive examination of a broad range of biomarkers used for the diagnosis and prediction of treatment outcomes in major depressive disorder (MDD). Genetic, epigenetic, serum, cerebrospinal fluid (CSF), and neuroimaging biomarkers are analyzed in depth, as well as the integration of new technologies such as digital phenotyping and machine learning. The intricate interplay between biological and psychological elements is emphasized as essential for tailoring MDD management strategies. In addition, the evolving link between psychotherapy and biomarkers is explored to uncover potential associations that shed light on treatment response. This analysis underscores the importance of individualized approaches in the treatment of MDD that integrate advanced biological insights into clinical practice to improve patient outcomes.

Lysophosphatidylcholines modulate immunoregulatory checkpoints in peripheral monocytes and are associated with mortality in people with acute liver failure

BACKGROUND & AIMS

Acute liver failure (ALF) is a life-threatening disease characterised by high-grade inflammation and immunoparesis, which is associated with a high incidence of death from sepsis. Herein, we aimed to describe the metabolic dysregulation in ALF and determine whether systemic immune responses are modulated via the lysophosphatidylcholine (LPC)-autotaxin (ATX)-lysophosphatidylcholinic acid (LPA) pathway.

METHODS

Ninety-six individuals with ALF, 104 with cirrhosis, 31 with sepsis and 71 healthy controls (HCs) were recruited. Pathways of interest were identified by multivariate statistical analysis of proton nuclear magnetic resonance spectroscopy and untargeted ultraperformance liquid chromatography-mass spectrometry-based lipidomics. A targeted metabolomics panel was used for validation. Peripheral blood mononuclear cells were cultured with LPA 16:0, 18:0, 18:1, and their immune checkpoint surface expression was assessed by flow cytometry. Transcript-level expression of the LPA receptor (LPAR) in monocytes was investigated and the effect of LPAR antagonism was also examined in vitro.

RESULTS

LPC 16:0 was highly discriminant between ALF and HC. There was an increase in ATX and LPA in individuals with ALF compared to HCs and those with sepsis. LPCs 16:0, 18:0 and 18:1 were reduced in individuals with ALF and were associated with a poor prognosis. Treatment of monocytes with LPA 16:0 increased their PD-L1 expression and reduced CD155, CD163, MerTK levels, without affecting immune checkpoints on T and NK/CD56+T cells. LPAR1 and 3 antagonism in culture reversed the effect of LPA on monocyte expression of MerTK and CD163. MerTK and CD163, but not LPAR genes, were differentially expressed and upregulated in monocytes from individuals with ALF compared to controls.

CONCLUSION

Reduced LPC levels are biomarkers of poor prognosis in individuals with ALF. The LPC-ATX-LPA axis appears to modulate innate immune response in ALF via LPAR1 and LPAR3. Further investigations are required to identify novel therapeutic agents targeting these receptors.

IMPACT AND IMPLICATIONS

We identified a metabolic signature of acute liver failure (ALF) and investigated the immunometabolic role of the lysophosphatidylcholine-autotaxin-lysophosphatidylcholinic acid pathway, with the aim of finding a mechanistic explanation for monocyte behaviour and identifying possible therapeutic targets (to modulate the systemic immune response in ALF). At present, no selective immune-based therapies exist. We were able to modulate the phenotype of monocytes in vitro and aim to extend these findings to murine models of ALF as a next step. Future therapies may be based on metabolic modulation; thus, the role of specific lipids in this pathway require elucidation and the relative merits of autotaxin inhibition, lysophosphatidylcholinic acid receptor blockade or lipid-based therapies need to be determined. Our findings begin to bridge this knowledge gap and the methods used herein could be useful in identifying therapeutic targets as part of an experimental medicine approach.

Ocimum tenuiflorum extract (HOLIXERTM): Possible effects on hypothalamic-pituitary-adrenal (HPA) axis in modulating stress

Ocimum tenuiflorum is a sacred medicinal plant bestowed with multiple health benefits. This plant is traditionally considered an adaptogen. Many scientific studies have indicated the anti-stress potential of Ocimum tenuiflorum but with higher doses. The present study investigated the effects of HolixerTM (a clinically studied standardized Ocimum tenuiflorum extract) on modulating stress using two in vivo models, namely the swim endurance study in mice and forced swim test in rats. In addition, we explored the mechanism of action of HolixerTM on the HPA axis using two in vitro cell-based assays to check for its inhibitory effect on cortisol release and CRF1 receptor antagonistic activity. Ocimum tenuiflorum extract enhanced the swimming time in mice, reduced the stress-induced increase in immobility time, and prevented the increase in corticosterone in rats subjected to the forced swim test. Further, Ocimum tenuiflorum extract inhibited cortisol release and exhibited a significant CRF1 receptor antagonist activity. Thus, Ocimum tenuiflorum extract was found effective in managing stress, and the effect could be due to the inhibition of cortisol release and the antagonistic effect on the CRF1 receptors.

Transcriptome Profiling of the Dorsomedial Prefrontal Cortex in Suicide Victims

The default mode network (DMN) plays an outstanding role in psychiatric disorders. Still, gene expressional changes in its major component, the dorsomedial prefrontal cortex (DMPFC), have not been characterized. We used RNA sequencing in postmortem DMPFC samples to investigate suicide victims compared to control subjects. 1400 genes differed using log2FC > ±1 and adjusted p-value < 0.05 criteria between groups. Genes associated with depressive disorder, schizophrenia and impaired cognition were strongly overexpressed in top differentially expressed genes. Protein−protein interaction and co-expressional networks coupled with gene set enrichment analysis revealed that pathways related to cytokine receptor signaling were enriched in downregulated, while glutamatergic synaptic signaling upregulated genes in suicidal individuals. A validated differentially expressed gene, which is known to be associated with mGluR5, was the N-terminal EF-hand calcium-binding protein 2 (NECAB2). In situ hybridization histochemistry and immunohistochemistry proved that NECAB2 is expressed in two different types of inhibitory neurons located in layers II-IV and VI, respectively. Our results imply extensive gene expressional alterations in the DMPFC related to suicidal behavior. Some of these genes may contribute to the altered mental state and behavior of suicide victims.

Addressing psychiatric disorders and genetics: the meaningful use of comics for health information

In the fields of healthcare and education, comics have shown considerable academic and teaching importance, with their combination of text and images. As a well-known character in comics, Batman allows us to discuss several relevant topics, from the outcomes in adulthood of experiencing parental death in childhood to genetic and epigenetic changes that may be factors of vulnerability to psychiatric disorders in adulthood. In this text, a narrative of Batman is developed, demonstrating the possibility of using it in an academic context and intending at paying greater attention to patients' history and the relationship between genetics and behaviour.

Genome-wide association study of suicidal behaviour severity in mood disorders

OBJECTIVE

Suicide is a major public health problem and it has a prominent genetic component. We performed a genome-wide association study (GWAS) of suicidal behaviour severity.

METHODS

Suicide behaviour severity was assessed within the Schedules for Clinical Assessment in Neuropsychiatry in our mood disorder sample (n = 3506) for the GWAS. We also performed polygenic risk score analyses to explore genetic sharing between suicidal behaviour severity and a number of phenotypes, including bipolar disorder, major depressive disorder, alcoholism, post-traumatic stress disorder, impulsivity, insomnia, educational attainment, loneliness, maltreatment, and amygdala volume.

RESULTS

We did not detect genome-wide significant findings at the single-marker or gene level. We report a number of suggestive single-marker and gene-based findings. Our polygenic risk score analyses did not yield significant findings with these phenotypes.

CONCLUSIONS

Larger sample sizes are required to detect moderate effects.

The Interaction Effects of Suicidal Ideation and Childhood Abuse on Brain Structure and Function in Major Depressive Disorder Patients

Suicidal ideation (SI) is a direct risk factor for suicide in patients with depression. Regarding the emergence of SI, previous studies have discovered many risk factors, including childhood abuse as the major public problem. Previous imaging studies have demonstrated that SI or childhood abuse has effects on brain structure and function, respectively, but the interaction effects between them have not been fully studied. To explore the interaction effect between SI and childhood abuse, 215 patients with major depressive disorder completed the Childhood Trauma Questionnaire to evaluate childhood abuse and Beck's Scale for Suicidal Ideation to evaluate SI. Then, they completed magnetic resonance imaging (MRI) within one week after completing questionnaires. Respectively, we preprocessed the structural and functional images and analyzed gray matter volumes (GMV) and mean fractional amplitude of low-frequency fluctuation (mfALFF) values. Results showed that the changes of GMV in the cuneus, precuneus, paracentric lobule, inferior frontal gyrus, and caudate nucleus and local activity in cuneal and middle temporal gyrus are in relation with SI and childhood abuse. And in left caudate, SI and childhood abuse interact with each other on the influence of GMV. That is, the influence of SI in GMV was related to childhood abuse, and the influence of childhood abuse in GMV was also related to SI. Therefore, the combination of SI and childhood abuse based on imaging should help us better understand the suicide ideation developing mechanism and propose more effective targeted prevention strategies for suicide prevention.

Polymorphisms of stress pathway genes and emergence of suicidal ideation at antidepressant treatment onset

The prescription of antidepressant drugs is one of the most frequently used strategies to prevent suicide and suicidal behavior. However, some patients develop suicidal ideation at antidepressant treatment onset, a phenomenon known as treatment-emergent suicidal ideation (TESI). Few studies have explored TESI pharmacogenomics. As the Hypothalamic-Pituitary-Adrenal (HPA) axis might be implicated in suicidal behavior, we assessed the relationship between TESI and single nucleotide polymorphisms (SNPs) in the HPA axis-implicated NR3C1 (n = 7 SNPs), FKBP5 (n = 5 SNPs), AVPR1B (n = 1 SNPs), CRHR1 (n = 1 SNPs), and SKA2 (n = 1 SNPs) genes, in a sample of 3566 adult outpatients with depression for whom an antidepressant treatment was introduced. General practitioners and psychiatrists throughout France followed participants for 6 weeks after the initial prescription of tianeptine, an antidepressant molecule showing mu agonism. Suicidal ideation was assessed with item 10 of the Montgomery-Åsberg Depression Rating Scale (item dedicated to suicidal ideation) at baseline, and at week 2, 4, and 6 of treatment. Within the informative sample, 112 patients reported TESI and 384 did not. TESI was significantly associated with the TT genotype of the SNP rs6902321 in FKBP5 (OR = 1.76, 95% CI = [1.07; 2.90]; p-value = 0.03) and the GG/AG genotype of the SNP rs7208505 in SKA2 (OR = 1.85, 95% CI = [1.03;3.33]; p-value = 0.04). These associations were not significant after multiple test correction. Nevertheless, our results suggest a possible involvement of HPA axis elements in treatment-emergent suicidal ideation (TESI).

Association of childhood trauma and genetic variability of CRH-BP and FKBP5 genes with suicidal behavior in bipolar patients

BACKGROUND

Around 8% of bipolar disorder (BD) patients die by suicide every year, accounting for the highest rate among the psychiatric population. Suicidal behavior (SB) is mediated by an intertwining system of extrinsic and intrinsic factors. Childhood trauma (CT) and gene variants of the stress-management hypothalamic-pituitary-adrenal (HPA) axis have been reported as risk factors for SB. The aim of this study was to elucidate the association of CT and HPA axis genetic variants with SB.

METHODS

135 BD patients were recruited for clinical assessment of CT and SB by means of the Childhood Trauma Questionnaire (CTQ) and the Columbia Suicide Severity Rating Scale (C-SSRS), respectively. A total of 28 single nucleotide polymorphisms (SNPs) from 8 HPA axis genes (POMC, NR3C2, CRH-BP, NR3C1, FKBP5, CRHR2, CRHR1, and MC2R) were genotyped.

RESULTS

The analyses showed an association of total CTQ score (p = 0.003), emotional abuse (p = 0.001), sexual abuse (p = 0.005) and emotional neglect (p = 0.005) with SB. CRH-BP rs7728378-C carriers (p = 0.004; OR = 3.05), FKBP5 rs3777747-AA (p = 0.039; OR = 0.34) and FKBP5 rs2766533-GG genotypes (p = 0.001; OR = 2.93) were associated with SB although only rs2766533 survived multiple test correction. No gene-environment interaction was found.

LIMITATIONS

The relatively small sample size limits the statistical power to detect smaller environmental and genetic effects. Cross-sectional data collection in psychometric assessments can yield biased data.

CONCLUSIONS

The present study characterizes novel SB risk factors and replicates previous findings in BD patients. CT and variability in CRH-BP and FKBP5 genes should be further studied for a better understanding of SB and ultimately help in suicide prevention.

Genetic predictor of current suicidal ideation in US service members deployed to Iraq and Afghanistan

OBJECTIVE

Suicide is one of the ten leading causes of death in United States and the suicide rate in the military population has increased since the start of the Iraq and Afghanistan wars. However, few biomarkers for current suicidal ideation (CSI) have been identified. The current study examined the association of four candidate genes with CSI in active duty US Army Special Operations Command and National Guard units (n = 3,889) who served in Iraq and Afghanistan between November 2009 and July 2014.

METHODS

Current PTSD symptoms and CSI were assessed using the PTSD Checklist (PCL) and PHQ-9, respectively. Traumatic events were assessed using items from the Life Events Checklist (LEC) that met the DSM-IV PTSD criteria of a traumatic stressor. All genotypes of saliva DNA were discriminated using the TaqMan 5'-exonuclease assay.

RESULTS

The associations between CSI and brain-derived neurotrophic factor (BDNF), FK506 binding protein (FKBP5), catechol-O-methyltransferase (COMT), or S100A10 (p11) were examined. We found CSI was associated with BDNF (OR = 1.5, 95% CI = 1.5-1.8, P = 0.0002), but not FKBP5, COMT and p11. Female soldiers reported CSI more often than males (χ2 = 7.403, p = 0.0065), although gender did not affect CSI severity. In addition, associations were found between CSI and depression, PTSD, and BDNF, but not traumatic events. The BDNF Val66Met contributed to the severity of CSI even after adjusting to PTSD, depression and LEC.

CONCLUSIONS

The associations of BDNF with CSI and its severity suggest that BDNF may be a predictor of suicidal risk and present an opportunity to develop laboratory tools with clinical implications in suicide prevention and treatment.

Influence of CRHR1 Polymorphisms and Childhood Abuse on Suicide Attempts in Affective Disorders: A GxE Approach

Background: Previous studies have shown that the hypothalamus-pituitary-adrenal-axis (HPA-axis) is closely involved in the development of affective disorders. Given that early life events are also linked to dysregulation of the same system, there might be an association between childhood adversities and suicidal behavior in affective disorders, moderated by HPA-axis genes. We aimed to investigate a potential association between childhood trauma and previous suicide attempts in affective disorder patients, moderated by variants of the corticotropin-releasing hormone receptor 1 (CRHR1) gene. Methods: The current pilot study is part of an ongoing study on suicidal behavior in affective disorders (VieSAD). Two hundred fifty eight Caucasian affective disorder patients were assessed at the Department of Psychiatry and Psychotherapy of the Medical University Vienna and the Karl Landsteiner University for Health and Science. An assemblage of psychiatric interviews was performed (e.g., SCAN, HAMD, SBQ-R, CTQ) and DNA samples of peripheral blood cells were genotyped with TaqMan® SNP Genotyping Assays (rs7209436, rs4792887, rs110402, rs242924, and rs242939). Results: Neither genetic, nor haplotypic associations between CRHR1 polymorphisms and previous suicide attempts could be established for the present sample. Using a binary logistic regression model, significant gene-environment-interactions were found for the single nucleotide polymorphisms (SNPs) rs7209436 and rs110402, reflecting the impact of childhood trauma and CRHR1 polymorphisms on previous suicide attempts. Limitations: A larger sample size will be required to ultimately elucidate the link between childhood trauma and the HPA axis in suicidal behavior. Conclusion: This pilot study presents promising gene-environment-interaction findings in affective disorder patients with a history of suicide attempts.

Epigenetic Changes in the CRH Gene are Related to Severity of Suicide Attempt and a General Psychiatric Risk Score in Adolescents

The aim of this study, comprising 88 suicide attempters, was to identify hypothalamic-pituitary-adrenal (HPA) -axis coupled CpG-sites showing methylation shifts linked to severity of the suicide attempt. Candidate methylation loci were further investigated as risk loci for a general psychiatric risk score in two cohorts of adolescents (cohort 1 and 2). The genome-wide methylation pattern was measured in whole blood using the Illumina Infinium Methylation EPIC BeadChip. Subjects were stratified into high-risk and low-risk groups based on the severity of the suicidal behavior. We included CpG sites located within 2000 basepairs away from transcriptional start site of the following HPA-axis coupled genes: corticotropin releasing hormone (CRH), corticotropin releasing hormone binding protein (CRHBP), corticotropin releasing hormone receptor 1 (CRHR1), corticotropin releasing hormone receptor 2 (CRHR2), FK506-binding protein 51 (FKBP5) and the glucocorticoid receptor (NR3C1). The methylation state of two corticotropin releasing hormone (CRH)-associated CpG sites were significantly hypomethylated in the high-risk group of suicide attempters (n = 31) (cg19035496 and cg23409074) (p < 0.001). Adolescent cohort 1 and 2 consisted of 129 and 93 subjects, respectively, and were stratified by the in silico generated DAWBA measurements of a general psychiatric risk score into high-risk group (>~50% risk) or controls. In adolescent cohort 2, cg19035496 was hypermethylated in subjects with a high general psychiatric risk score. Our results show epigenetic changes in the CRH gene related to severity of suicide attempt in adults and a general psychiatric risk score in adolescents.

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Two CRH-associated CpG sites were significantly hypomethylated in the high-risk group of suicide attempters.

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In adolescent cohort, cg19035496 was hypermethylated in subjects with a high general psychiatric risk score.

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Epigenetic modulatory effects on the HPA axis dysregulation are associated with psychiatric illness and suicidal behavior.

In this study, comprising 88 suicide attempters, we aimed to identify epigenetic changes in stress system linked to severity of the suicide attempt. In the next step, we investigated if the same epigenetic changes could be detected in adolescents with high risk for psychiatric illness. The methylation pattern was measured in blood and subjects were stratified into high-risk and low-risk groups based on the severity of the suicidal behavior. One corticotropin releasing hormone (CRH)-a key regulator of stress system-associated CpG site showed less methylation in the high-risk group and was hypermethylated in adolescents with a high general psychiatric risk score. Epigenetic changes in the CRH gene were related to severity of suicide attempt in adults and a general psychiatric risk score in adolescents.

The FKBP51 Glucocorticoid Receptor Co-Chaperone: Regulation, Function, and Implications in Health and Disease

Among the chaperones and co-chaperones regulating the glucocorticoid receptor (GR), FK506 binding protein (FKBP) 51 is the most intensely investigated across different disciplines. This review provides an update on the role of the different co-chaperones of Hsp70 and Hsp90 in the regulation of GR function. The development leading to the focus on FKBP51 is outlined. Further, a survey of the vast literature on the mechanism and function of FKBP51 is provided. This includes its structure and biochemical function, its regulation on different levels—transcription, post-transcription, and post-translation—and its function in signaling pathways. The evidence portraying FKBP51 as a scaffolding protein organizing protein complexes rather than a chaperone contributing to the folding of individual proteins is collated. Finally, FKBP51’s involvement in physiology and disease is outlined, and the promising efforts in developing drugs targeting FKBP51 are discussed.