Interactions between FKBP5 variation and environmental stressors in adolescent Major Depression

Hemispheric asymmetries and network dysfunctions in adolescent depression: A neuroimaging study using resting-state functional magnetic resonance imaging

BACKGROUND

Currently, adolescent depression is one of the most significant public health concerns, markedly influencing emotional, cognitive, and social maturation. Despite advancements in distinguish the neurobiological substrates underlying depression, the intricate patterns of disrupted brain network connectivity in adolescents warrant further exploration.

AIM

To elucidate the neural correlates of adolescent depression by examining brain network connectivity using resting-state functional magnetic resonance imaging (rs-fMRI).

METHODS

The study cohort comprised 74 depressed adolescents and 59 healthy controls aged 12 to 17 years. Participants underwent rs-fMRI to evaluate functional connectivity within and across critical brain networks, including the visual, default mode network (DMN), dorsal attention, salience, somatomotor, and frontoparietal control networks.

RESULTS

Analyses revealed pronounced functional disparities within key neural circuits among adolescents with depression. The results demonstrated existence of hemispheric asymmetries characterized by enhanced activity in the left visual network, which contrasted the diminished activity in the right hemisphere. The DMN facilitated increased activity within the left prefrontal cortex and reduced engagement in the right hemisphere, implicating disrupted self-referential and emotional processing mechanisms. Additionally, an overactive right dorsal attention network and a hypoactive salience network were identified, underscoring significant abnormalities in attentional and emotional regulation in adolescent depression.

CONCLUSION

The findings from this study underscore distinct neural connectivity disruptions in adolescent depression, underscoring the critical role of specific neurobiological markers for precise early diagnosis of adolescent depression. The observed functional asymmetries and network-specific deviations elucidate the complex neurobiological architecture of adolescent depression, supporting the development of targeted therapeutic strategies.

Genetically engineered mouse models of FK506-binding protein 5

FK506 binding protein 51 (FKBP51) is a molecular chaperone that influences stress response. In addition to having an integral role in the regulation of steroid hormone receptors, including glucocorticoid receptor, FKBP51 has been linked with several biological processes including metabolism and neuronal health. Genetic and epigenetic alterations in the gene that encodes FKBP51, FKBP5, are associated with increased susceptibility to multiple neuropsychiatric disorders, which has fueled much of the research on this protein. Because of the complexity of these processes, animal models have been important in understanding the role of FKBP51. This review examines each of the current mouse models of FKBP5, which include whole animal knockout, conditional knockout, overexpression, and humanized mouse models. The generation of each model and observational details are discussed, including behavioral phenotypes, molecular changes, and electrophysiological alterations basally and following various challenges. While much has been learned through these models, there are still many aspects of FKBP51 biology that remain opaque and future studies are needed to help illuminate these current gaps in knowledge. Overall, FKBP5 continues to be an exciting potential target for stress-related disorders.

Research trend of epigenetics and depression: adolescents' research needs to strengthen

Objective

With its high prevalence, depression's pathogenesis remains unclear. Recent attention has turned to the interplay between depression and epigenetic modifications. However, quantitative bibliometric analyses are lacking. This study aims to visually analyze depression epigenetics trends, utilizing bibliometric tools, while comprehensively reviewing its epigenetic mechanisms.

Methods

Utilizing the Web of Science core dataset, we collected depression and epigenetics-related studies. Employing VOSViewer software, we visualized data on authors, countries, journals, and keywords. A ranking table highlighted field leaders.

Results

Analysis encompassed 3,469 depression epigenetics studies published from January 2002 to June 2023. Key findings include: (1) Gradual publication growth, peaking in 2021; (2) The United States and its research institutions leading contributions; (3) Need for enhanced collaborations, spanning international and interdisciplinary efforts; (4) Keyword clustering revealed five main themes-early-life stress, microRNA, genetics, DNA methylation, and histone acetylation-highlighting research hotspots; (5) Limited focus on adolescent depression epigenetics, warranting increased attention.

Conclusion

Taken together, this study revealed trends and hotspots in depression epigenetics research, underscoring global collaboration, interdisciplinary fusion, and multi-omics data's importance. It discussed in detail the potential of epigenetic mechanisms in depression diagnosis and treatment, advocating increased focus on adolescent research in this field. Insights aid researchers in shaping their investigative paths toward understanding depression's epigenetic mechanisms and antidepressant interventions.

Risk for Depressive Symptoms Among Adolescents with a History of Adversity: Unique Role of Stress Appraisals

Lifetime social adversity predicts elevated depressive symptoms in adolescence. However, most adversity-exposed youth do not develop depression, highlighting the importance of examining risk and protective factors. The present study leveraged a multi-method approach, incorporating self-report, interview, and independent coding to examine whether appraisals of recent stressors moderate the effect of social adversity on depressive symptoms in 81 adolescent girls (M_age = 16.30 years, SD = .85). We utilized semi-structured interviews of lifetime adversity and recent stressors and semi-structured interviews and self-reports of depressive symptoms. Stress appraisals were calculated by regressing youths' subjective estimations of event stressfulness and dependence on estimations of independent coders. Lifetime social adversity predicted elevated depressive symptoms more strongly in girls who appraised interpersonal events as more stressful and dependent on their actions, providing insight into individual differences in depressive symptoms in adversity-exposed adolescents.

Longitudinal relation between maladaptive parenting and nonsuicidal self-injury among Chinese early adolescents: The roles of internalizing symptoms and FKBP5 gene variation

BACKGROUND

While increasing research has effectively documented that maladaptive parenting is a significant risk factor for adolescent nonsuicidal self-injury, the process mechanism and gene-by-environment interaction in this relation among Chinese early adolescents are still poorly understood.

METHODS

In this study, a multi-informant longitudinal design was applied to investigate the indirect effect of internalizing symptoms in the relation between maladaptive parenting and nonsuicidal self-injury, and to examine how FKBP5 gene variation moderates these association. A total of 1718 Chinese Han early adolescents (44.30 % girls; M_age at Wave 1 = 10.35) and their parents participated this study.

RESULTS

The results showed that maladaptive parenting significantly predicts adolescent nonsuicidal self-injury after six months. Maladaptive parenting was also indirectly related to nonsuicidal self-injury via internalizing symptoms. Moreover, using a cumulative genetic score approach, the results showed that FKBP5 gene variation moderates the predictive effect of maladaptive parenting on internalizing symptoms and also moderates the indirect effect of internalizing symptoms between maladaptive parenting and nonsuicidal self-injury. These effects were more salient among adolescents with high (versus low) FKBP5 gene related cumulative genetic score linked to heightened stress reactivity.

LIMITATIONS

Our study only obtained two waves of data. Three waves of data would be more suitable for examining a mediation model.

CONCLUSION

This study reveals the process mechanism between maladaptive parenting and nonsuicidal self-injury and highlights the significance of gene-by-environment interaction to explain the emergence of nonsuicidal self-injury among adolescents.

Biomarkers in Child and Adolescent Depression

Despite the significant prevalence of Major Depressive Disorder in the pediatric population, the pathophysiology of this condition remains unclear, and the treatment outcomes poor. Investigating tools that might aid in diagnosing and treating early-onset depression seems essential in improving the prognosis of the future disease course. Recent studies have focused on searching for biomarkers that constitute biochemical indicators of MDD susceptibility, diagnosis, or treatment outcome. In comparison to increasing evidence of possible biomarkers in adult depression, the studies investigating this subject in the youth population are lacking. This narrative review aims to summarize research on molecular and biochemical biomarkers in child and adolescent depression in order to advocate future directions in the research on this subject. More studies on depression involving the youth population seem vital to comprehend the natural course of the disease and identify features that may underlie commonly observed differences in treatment outcomes between adults and children.

Psychosocial moderators of polygenic risk for suicidal ideation: Results from a 7-year population-based, prospective cohort study of U.S. veterans

Polygenic risk scores (PRS) may help inform the etiology of suicidal thoughts and behaviors. In this study, we evaluated whether a suicidality PRS derived from a large genome-wide association study (GWAS) of suicidality from the UK Biobank (N = 122,935) predicted suicidal ideation (SI) in a 7-year population-based, prospective cohort of European-American US veterans (N = 1326). Results revealed that 8.8% (n = 115) of veterans developed new-onset SI, 4.0% (n = 52) had chronic SI, 3.4% (n = 31) had remitted SI, and 83.8% (n = 1128) denied SI over the study period. Suicidality PRS_standardized was positively associated with chronic SI (relative risk ratio [RRR] = 4.54, 95% confidence interval [CI] = 1.01-20.48) and new-onset SI (RRR = 2.97, 95%CI = 1.22-7.23), and negatively associated with remitted SI (RRR = 0.12, 95% CI = 0.02-0.60). Among veterans with higher suicidality PRS, those with higher baseline dispositional optimism had a lower likelihood of chronic SI (RRR = 0.67, 95% CI = 0.49-0.91) and higher likelihood of remitted SI (RRR = 1.98, 95% CI = 1.18-3.31). Among veterans with higher suicidality PRS, those with higher baseline levels of social support were less likely to develop new-onset SI (RRR = 0.95, 95% CI = 0.92-0.99). These interaction effects were enriched for genes implicated in neuron recognition and development, while the PRS main effect was enriched for genes involved in mannosylation. Collectively, results of this study suggest that suicidality PRS is linked prospectively to symptomatic courses of SI, and that dispositional optimism and social support moderate these associations. Interventions targeting these modifiable psychosocial factors may help mitigate risk of SI in veterans with high polygenic risk for suicidality.

Associations of FKBP5 polymorphisms and methylation and parenting style with depressive symptoms among Chinese adolescents

BACKGROUND

Genetic factors may interplay with environmental stressors to contribute to risks of depressive symptoms. This study aimed to investigate the association of FKBP5 polymorphisms and DNA methylation with depressive symptoms among Chinese adolescents, considering the role of parenting style.

METHODS

This study used a nested case-control study design based on a cohort study, and the case (n = 120) and control groups (n = 118) were matched with age. Depressive symptoms, parenting style, and other demographics were measured. Fourteen potential polymorphisms and one promoter region in the FKBP5 gene were selected for genotyping and methylation analysis.

RESULTS

In the adjusted models, a significant association between FKBP5 rs7757037 and depressive symptoms was found in the codominant model (AG vs. GG; adjusted odds ratio [AOR] = 2.56, 95% CI = 1.13-5.78) and dominant model (AA+AG vs. GG; AOR = 2.38, 95% CI = 1.11-5.120); rs2817032 and rs2817035 polymorphisms were associated with depressive symptoms in the codominant model and dominant model. Significant interactions between rs7757037 and the father's parenting style were found in the codominant model (P = 0.043) and dominant model (P = 0.043), but the gene-environment interactions were not significant after correcting for multiple testing. Moreover, the significant main effects of FKBP5 methylation status on depressive symptoms were not observed, and there was no significant interaction between FKBP5 methylation status and parenting style on depressive symptoms.

CONCLUSIONS

Further studies are required to confirm the effect of FKBP5 polymorphisms and methylation as well as their interactions with parenting styles in larger samples.

Regulatory functions of FKBP5 intronic regions associated with psychiatric disorders

The FKBP5 gene codifies a co-chaperone protein associated with the modulation of glucocorticoid receptor interaction involved in the adaptive stress response. The FKBP5 intracellular concentration affects the binding affinity of the glucocorticoid receptor (GR) to glucocorticoids (GCs). This gene has glucocorticoid response elements (GREs) located in introns 2, 5 and 7, which affect its expression. Recent studies have examined GRE activity and the effects of genetic variants on transcript efficiency and their contribution to susceptibility to behavioral disorders. Epigenetic changes and environmental factors can influence the effects of these allele-specific variants, impacting the response to GCs of the FKBP5 gene. The main epigenetic mark investigated in FKBP5 intronic regions is DNA methylation, however, few studies have been performed for all GREs located in these regions. One of the major findings was the association of low DNA methylation levels in the intron 7 of FKBP5 in patients with psychiatric disorders. To date, there are no reports of DNA methylation in introns 2 and 5 of the gene associated with diagnoses of psychiatric disorders. This review highlights what has been discovered so far about the relationship between polymorphisms and epigenetic targets in intragenic regions, and reveals the gaps that need to be explored, mainly concerning the role of DNA methylation in these regions and how it acts in psychiatric disease susceptibility.

Hypothalamus volume and DNA methylation of stress axis genes in major depressive disorder: A CAN-BIND study report

Dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis is considered one of the mechanisms underlying the development of major depressive disorder (MDD), but the exact nature of this dysfunction is unknown. We investigated the relationship between hypothalamus volume (HV) and blood-derived DNA methylation in MDD. We obtained brain MRI, clinical and molecular data from 181 unmedicated MDD and 90 healthy control (HC) participants. MDD participants received a 16-week standardized antidepressant treatment protocol, as part of the first Canadian Biomarker Integration Network in Depression (CAN-BIND) study. We collected bilateral HV measures via manual segmentation by two independent raters. DNA methylation and RNA sequencing were performed for three key HPA axis-regulating genes coding for the corticotropin-binding protein (CRHBP), glucocorticoid receptor (NR3C1) and FK506 binding protein 5 (FKBP5). We used elastic net regression to perform variable selection and assess predictive ability of methylation variables on HV. Left HV was negatively associated with duration of current episode (ρ = -0.17, p = 0.035). We did not observe significant differences in HV between MDD and HC or any associations between HV and treatment response at weeks 8 or 16, overall depression severity, illness duration or childhood maltreatment. We also did not observe any differentially methylated CpG sites between MDD and HC groups. After assessing functionality by correlating methylation levels with RNA expression of the respective genes, we observed that the number of functionally relevant CpG sites differed between MDD and HC groups in FKBP5 (χ² = 77.25, p < 0.0001) and NR3C1 (χ² = 7.29, p = 0.007). Cross-referencing functionally relevant CpG sites to those that were highly ranked in predicting HV in elastic net modeling identified one site from FKBP5 (cg03591753) and one from NR3C1 (cg20728768) within the MDD group. Stronger associations between DNA methylation, gene expression and HV in MDD suggest a novel putative molecular pathway of stress-related sensitivity in depression. Future studies should consider utilizing the epigenome and ultra-high field MR data which would allow the investigation of HV sub-fields.

Stress modulates Ahi1-dependent nuclear localization of Ten-Eleven Translocation Protein 2

Major depression disorder (MDD) is one of the most common psychiatric diseases. Recent evidence supports that environmental stress affects gene expression and promotes the pathological process of depression through epigenetic mechanisms. Three Ten-Eleven Translocation (Tet) enzymes are epigenetic regulators of gene expression that promote 5-hydroxymethylcytosine (5hmC) modification of genes. Here, we show that the loss of Tet2 can induce depression-like phenotypes in mice. Paradoxically, using the paradigms of chronic stress, such as chronic mild stress (CMS) and chronic social defeat stress (CSDS), we found that depressive behaviors were associated with increased Tet2 expression but decreased global 5hmC level in hippocampus. We examined the genome-wide 5hmC profile in the hippocampus of Tet2 knockout mice and identified 651 dynamically hydroxymethylated regions, some of which overlapped with known depression-associated loci. We further showed that chronic stress could induce the abnormal nuclear translocation of Tet2 protein from cytosol. Through Tet2 immunoprecipitation and mass spectrum analyses, we identified a cellular trafficking protein, Abelson helper integration site-1 (Ahi1), which could interact with Tet2 protein. Ahi1 knockout or knockdown caused the accumulation of Tet2 in cytosol. The reduction of Ahi1 protein under chronic stress explained the abnormal Ahi1-dependent nuclear translocation of Tet2. These findings together provide the evidence for a critical role of modulating Tet2 nuclear translocation in regulating stress response.

Association of FKBP5 gene variants with depression susceptibility: A comprehensive meta-analysis

BACKGROUND

This comprehensive meta-analysis aimed to combine data from different studies and to estimate the association between FKBP5 polymorphisms and depression.

METHODS

We performed a meta-analysis of observational studies. An electronic search was conducted on four databases for articles published before July 1, 2020.

RESULTS

A total of 5125 patients with depression and 8399 controls from 16 independent studies were included in the analysis. The results showed that FKBP5 rs1360780 was associated with the risk of depression in the codominant model (CT vs. CC; OR = 1.10, 95% CI = 1.00-1.20, P = .04); rs4713916 polymorphism was associated with depression in the codominant model (AG vs. GG; OR = 1.19, 95% CI = 1.05-1.34, P = .008) and recessive model (AA vs. AG + GG; OR = 0.74, 95% CI = 0.56-0.99, P = .04); a significant association between rs3800373 and depression was found in the codominant genetic model (AC vs. AA; OR = 1.18, 95% CI = 1.05-1.34, P = .007) and dominant model (CC + AC vs. AA; OR = 1.15, 95% CI = 1.03-1.30, P = .02); there was no significant association of FKBP5 rs9470080 or rs9296158 with depression in any genetic model (P > .05). No publication bias was observed in our analysis. Moreover, sensitivity analyses demonstrated the Zobel's study significantly affected the heterogeneity for rs4713916 and rs3800373.

CONCLUSIONS

FKBP5 rs1360780 was associated with an increased risk of depression in the codominant model. We also found that rs4713916 and rs3800373 were involved in depression, rs4713916 was positively associated with depression in the codominant model and recessive model, and rs3800373 was related to an elevated risk of depression in the codominant model and dominant model.

Biological correlates of early life stressful events in major depressive disorder

Major depressive disorder (MDD) is the most common psychiatric disorder and responds for important psychosocial consequences. Stressful life events, especially early life stress (ELS), contribute to an increased probability to develop MDD, leading in particular to severe and chronic manifestation and unfavorable treatment outcome. The association between ELS and MDD seems to have biological bases, consisting in dysregulations occurring at different levels. The aim of this narrative review is to propose an overview of the literature ranging from genetic, epigenetic, expression and protein to neuroimaging correlates underlying this relationship. A search on Pubmed of studies assessing biological correlates of ELS in MDD development, focusing on human studies conducted in both peripheral and brain tissues, was performed. Evidence indicated that the hypothalamic-pituitary-adrenal (HPA) axis and the serotonergic, dopaminergic, neurotrophin and oxytocin systems might play a role in the mediation between ELS and MDD. The most consistent results were found for genetic and epigenetic studies and indicated a joint involvement of the systems mentioned. Expression studies are less numerous and point to an involvement of stress-related systems. Concerning protein studies, the main mediators are markers related to the inflammatory and immune systems. Neuroimaging studies aiming at evaluating brain alterations connecting ELS and MDD in relation to biomarkers indicated the hippocampus, the amygdala and the frontal cortex as important anatomical mediators. These findings can build the bases for future research and clinical interventions; indeed, the clarification of biological mechanisms mediating the relationship between ELS and MDD can lead to new and individualized preventive and therapeutic possibilities.

Association of FKBP5 polymorphisms with patient susceptibility to coronary artery disease comorbid with depression

BACKGROUND

Coronary artery disease (CAD) and depression cause great burden to society and frequently co-occur. The exact mechanisms of this comorbidity are unclear. FK506-binding protein 51 (FKBP51) is correlated with cardiovascular disease and depression. The aim of this study was to determine the role of the seven single nucleotide polymorphisms (SNPs) of FKBP5 that code FKBP51, namely, rs1360780 (C>T), rs2817032 (T>C), rs2817035 (G>A), rs9296158 (G>A), rs9470079 (G>A), rs4713902 (T>C), and rs3800373 (C>T) in a patient's susceptibility to comorbid CAD and depression.

METHODS

We enrolled 271 Northern Chinese Han patients with CAD, including 123 patients with depression and 147 patients without depression. We also included 113 healthy controls that match the patients' sex and age. Genomic DNA from whole blood was extracted, and seven SNPs were assessed using MassArray method. Patient Health Questionnaire-9 was applied to access the depression.

RESULTS

The GA genotype for rs9470079 was associated with a significantly decreased risk of CAD (odds ratio = 0.506, 95% confidence interval = 0.316-0.810, P = 0.005) when the GG genotype was used as reference. A statistically significant difference was observed among females but not among males in the rs9470079 genotype and allele frequency. Patients with CAD were further divided into CAD+D and CAD-D groups according to the presence of comorbid depression and were compared with the controls. Significant differences were found regarding the genotype and allele frequency of rs2817035 and rs9470079 in CAD+H groups compared with the control subjects in all groups and the female groups (P < 0.05).

CONCLUSIONS

The current study found a remarkable association between FKBP5 gene variations and the risk of comorbid CAD and depression in a north Chinese population. rs9470079 may be a potential gene locus for the incidence of comorbid CAD and depression.

Interaction between FKBP5 polymorphisms and childhood trauma on depressive symptoms in Chinese adolescents: The moderating role of resilience

BACKGROUND

Previous gene-environment studies on depression have examined the interaction between FKBP5 gene and childhood trauma, but the results are inconsistent and few studies have focused on Asian adolescents. Psychological resilience may explain for the inconsistency. We examined the interaction between FKBP5 gene and childhood trauma on depressive symptoms in Chinese adolescents, and firstly explored the moderating role of resilience in the relationship.

METHODS

This study comprised 942 participants (448 males, 47.6%) randomly recruited from four senior schools in Wuhan, Hubei of China. Depressive symptoms, childhood trauma, and resilience were respectively evaluated by the Center for Epidemiological Studies Depression Scale (CES-D), the Childhood Trauma Questionnaire (CTQ) and the Connor-Davidson Resilience Scale (CD-RISC). Three potentially functional FKBP5 polymorphisms were selected for genotyping.

RESULTS

Participants carrying minor alleles of FKBP5 polymorphisms (rs3800373, rs1360780, and rs4713916) and a haplotype derived from these variants displayed higher CES-D scores when exposed to childhood physical abuse after adjusting for demographic characteristics and resilience (all P < 0.01). The three-way interactions of FKBP5 SNPs, physical abuse, and resilience on depressive symptoms all yielded statistical significance after adjusting for demographic characteristics (β = -0.282 to -0.236; all P < 0.001).

LIMITATIONS

Cross-sectional design, self- reported measurements and limited genotyped FKBP5 polymorphisms.

CONCLUSION

FKBP5 variants in combination with childhood physical abuse may increase more pronounced depressive symptoms among Chinese adolescents, while resilience plays a moderating role in the associations. Future research to examine the exact mechanism of resilience in these associations is needed.

The cellular and molecular basis of major depressive disorder: towards a unified model for understanding clinical depression

Major depressive disorder (MDD) is considered a serious public health issue that adversely impacts an individual's quality of life and contributes significantly to the global burden of disease. The clinical heterogeneity that exists among patients limits the ability of MDD to be accurately diagnosed and currently, a symptom-based approach is utilized in many cases. Due to the complex nature of this disorder, and lack of precise knowledge regarding the pathophysiology, effective management is challenging. The aetiology and pathophysiology of MDD remain largely unknown given the complex genetic and environmental interactions that are involved. Nonetheless, the aetiology and pathophysiology of MDD have been the subject of extensive research, and there is a vast body of literature that exists. Here we overview the key hypotheses that have been proposed for the neurobiology of MDD and highlight the need for a unified model, as many of these pathways are integrated. Key pathways discussed include neurotransmission, neuroinflammation, clock gene machinery pathways, oxidative stress, role of neurotrophins, stress response pathways, the endocannabinoid and endovanilloid systems, and the endogenous opioid system. We also describe the current management of MDD, and emerging novel therapies, with particular focus on patients with treatment-resistant depression (TRD).