Pathogenic germline mutations in
lead to glycosylphosphatidylinositol biosynthesis deficiency (GPIBD). Individuals with pathogenic biallelic mutations in genes of the glycosylphosphatidylinositol ...(GPI)-anchor pathway exhibit cognitive impairments, motor delay, and often epilepsy. Thus far, the pathophysiology underlying the disease remains unclear, and suitable rodent models that mirror all symptoms observed in human patients have not been available. Therefore, we used CRISPR-Cas9 to introduce the most prevalent hypomorphic missense mutation in European patients,
:c.1022C > A (p.A341E), at a site that is conserved in mice. Mirroring the human pathology, mutant
mice exhibited deficits in motor coordination, cognitive impairments, and alterations in sociability and sleep patterns, as well as increased seizure susceptibility. Furthermore, immunohistochemistry revealed reduced synaptophysin immunoreactivity in
mice, and electrophysiology recordings showed decreased hippocampal synaptic transmission that could underlie impaired memory formation. In single-cell RNA sequencing,
-hippocampal cells exhibited changes in gene expression, most prominently in a subtype of microglia and subicular neurons. A significant reduction in
transcript levels in several cell clusters suggested a link to the signaling pathway of GPI-anchored ephrins. We also observed elevated levels of
transcripts, which might affect histamine metabolism with consequences for circadian rhythm. This mouse model will not only open the doors to further investigation into the pathophysiology of GPIBD, but will also deepen our understanding of the role of GPI-anchor-related pathways in brain development.
Abstract An important step in the malignant progression of HPV-associated lesions is the dysregulation of expression of the viral E6 and E7 oncogenes. This is often achieved through the loss of ...expression of E2, which represses the HPV LCR promoter and E6/E7 expression. Our previous studies confirmed a role for Brd4 in mediating the E2 transcriptional repression function, and identified JARID1C/SMCX and EP400 as contributors to E2-mediated repression. Here we show that TIP60, a component of the TIP60/TRRAP histone acetyltransferase complex, also contributes to the E2 repression function, and we extend our studies on SMCX. Di- and tri-methyl marks on histone H3K4 are reduced in the presence of E2 and SMCX, suggesting a mechanism by which SMCX contributes to E2-mediated repression of the HPV LCR. Together, these findings lead us to hypothesize that E2 recruits histone-modifying cellular proteins to the HPV LCR, resulting in transcriptional repression of E6 and E7.
Major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia spectrum disorders (SZ) exhibit considerable phenotypic and genetic overlap. However, the contribution of genetic factors to ...their shared psychopathological symptom dimensions remains unclear. The present exploratory study investigated genetic contributions to the symptom dimensions “Depression”, “Negative syndrome”, “Positive formal thought disorder”, “Paranoid-hallucinatory syndrome”, and “Increased appetite” in a transdiagnostic subset of the German FOR2107 cohort (n = 1042 patients with MDD, BD, or SZ). As replication cohort, a subset of the German/Austrian PsyCourse study (n = 816 patients with MDD, BD, or SZ) was employed. First, the relationship between symptom dimensions and common variants associated with MDD, BD, and SZ was investigated via polygenic risk score (PRS) association analyses, with disorder-specific PRS as predictors and symptom dimensions as outcomes. In the FOR2107 study sample, PRS for BD and SZ were positively associated with “Positive formal thought disorder”, the PRS for SZ was positively associated with “Paranoid-hallucinatory syndrome”, and the PRS for BD was negatively associated with “Depression”. The effects of PRS for SZ were replicated in PsyCourse. No significant associations were observed for the MDD PRS. Second, genome-wide association studies (GWAS) were performed for the five symptom dimensions. No genome-wide significant associations and no replicable suggestive associations (p < 1e−6 in the GWAS) were identified. In summary, our results suggest that, similar to diagnostic categories, transdiagnostic psychiatric symptom dimensions are attributable to polygenic contributions with small effect sizes. Further studies in larger thoroughly phenotyped psychiatric cohorts are required to elucidate the genetic factors that shape psychopathological symptom dimensions.
There is a lack of knowledge regarding the relationship between proneness to dimensional psychopathological syndromes and the underlying pathogenesis across major psychiatric disorders, i.e., Major ...Depressive Disorder (MDD), Bipolar Disorder (BD), Schizoaffective Disorder (SZA), and Schizophrenia (SZ). Lifetime psychopathology was assessed using the OPerational CRITeria (OPCRIT) system in 1,038 patients meeting DSM-IV-TR criteria for MDD, BD, SZ, or SZA. The cohort was split into two samples for exploratory and confirmatory factor analyses. All patients were scanned with 3-T MRI, and data was analyzed with the CAT-12 toolbox in SPM12. Psychopathological factor scores were correlated with gray matter volume (GMV) and cortical thickness (CT). Finally, factor scores were used for exploratory genetic analyses including genome-wide association studies (GWAS) and polygenic risk score (PRS) association analyses. Three factors (paranoid-hallucinatory syndrome, PHS; mania, MA; depression, DEP) were identified and cross-validated. PHS was negatively correlated with four GMV clusters comprising parts of the hippocampus, amygdala, angular, middle occipital, and middle frontal gyri. PHS was also negatively associated with the bilateral superior temporal, left parietal operculum, and right angular gyrus CT. No significant brain correlates were observed for the two other psychopathological factors. We identified genome-wide significant associations for MA and DEP. PRS for MDD and SZ showed a positive effect on PHS, while PRS for BD showed a positive effect on all three factors. This study investigated the relationship of lifetime psychopathological factors and brain morphometric and genetic markers. Results highlight the need for dimensional approaches, overcoming the limitations of the current psychiatric nosology.
Reduced processing speed is a core deficit in major depressive disorder (MDD) and has been linked to altered structural brain network connectivity. Ample evidence highlights the involvement of ...genetic-immunological processes in MDD and specific depressive symptoms. Here, we extended these findings by examining associations between polygenic scores for tumor necrosis factor-α blood levels (TNF-α PGS), structural brain connectivity, and processing speed in a large sample of MDD patients. Processing speed performance of n = 284 acutely depressed, n = 177 partially and n = 198 fully remitted patients, and n = 743 healthy controls (HC) was estimated based on five neuropsychological tests. Network-based statistic was used to identify a brain network associated with processing speed. We employed general linear models to examine the association between TNF-α PGS and processing speed. We investigated whether network connectivity mediates the association between TNF-α PGS and processing speed. We identified a structural network positively associated with processing speed in the whole sample. We observed a significant negative association between TNF-α PGS and processing speed in acutely depressed patients, whereas no association was found in remitted patients and HC. The mediation analysis revealed that brain connectivity partially mediated the association between TNF-α PGS and processing speed in acute MDD. The present study provides evidence that TNF-α PGS is associated with decreased processing speed exclusively in patients with acute depression. This association was partially mediated by structural brain connectivity. Using multimodal data, the current findings advance our understanding of cognitive dysfunction in MDD and highlight the involvement of genetic-immunological processes in its pathomechanisms.
Abstract
Bipolar disorder (BD) is a complex mood disorder with a strong genetic component. Recent studies suggest that microRNAs contribute to psychiatric disorder development. In BD, specific ...candidate microRNAs have been implicated, in particular
miR-137
,
miR-499a
,
miR-708
,
miR-1908
and
miR-2113
. The aim of the present study was to determine the contribution of these five microRNAs to BD development. For this purpose, we performed: (i) gene-based tests of the five microRNA coding genes, using data from a large genome-wide association study of BD; (ii) gene-set analyses of predicted, brain-expressed target genes of the five microRNAs; (iii) resequencing of the five microRNA coding genes in 960 BD patients and 960 controls and (iv) in silico and functional studies for selected variants. Gene-based tests revealed a significant association with BD for
MIR499A
,
MIR708
,
MIR1908
and
MIR2113
. Gene-set analyses revealed a significant enrichment of BD associations in the brain-expressed target genes of
miR-137
and
miR-499a-5p
. Resequencing identified 32 distinct rare variants (minor allele frequency < 1%), all of which showed a non-significant numerical overrepresentation in BD patients compared to controls (
p
= 0.214). Seven rare variants were identified in the predicted stem-loop sequences of
MIR499A
and
MIR2113
. These included rs142927919 in
MIR2113
(
p
nom
= 0.331) and rs140486571 in
MIR499A
(
p
nom
= 0.297). In silico analyses predicted that rs140486571 might alter the
miR-499a
secondary structure. Functional analyses showed that rs140486571 significantly affects
miR-499a
processing and expression. Our results suggest that
MIR499A
dysregulation might contribute to BD development. Further research is warranted to elucidate the contribution of the
MIR499A
regulated network to BD susceptibility.
The hallucinogenic "club drugs" 3,4-methylenedioxymethamphetamine (MDMA) and 5-methoxy-N, N-diisopropyltryptamine hydrochloride (Foxy), albeit to different degrees, remain popular as recreational ...drugs. Much is known about MDMA including observations that in comparison to female rodents, males appear to be more sensitive to the toxic effects associated with abuse. Less is known about the possible sex differences associated with the abuse of Foxy, especially when the consequences of its use are examined during the neuropsychological development period of adolescence. In the present study, adolescent male and female rats were given multiple doses of MDMA, Foxy, or saline across a series of 48-hr "weekends" under conditions approximating that of a rave. Behavioral testing occurred in adulthood when the rats were 131 days old and had been drug free for 66 days. Assessments included general activity, passive avoidance, and a series of Morris water maze spatial and nonspatial memory tasks. Depending on task demands, the performance of MDMA-treated rats was inferior to that of the Foxy-treated rats and saline controls. The performance of both drug groups was comparable and inferior to that of control rats on a spatial learning set task. Generally, greater impairments were observed in MDMA-treated rats than the Foxy-treated rats. Sex differences were observed on some but not all spatial tasks with MDMA-treated males performing significantly worse than similarly treated female rats. The results are in the context of putative sex-mediated differences in sensitivity to MDMA or Foxy and the disruptive effects of these drugs to central serotonergic systems that may contribute to cognitive deficits.
Depression is a common psychiatric disorder, affecting around 280 million people worldwide. Both genetic and environmental factors contribute to disease liability, likely via gene-environment ...interactions. Clinical observations as well as genetic findings suggest that inflammatory processes are involved in the pathophysiology of depression. One potential cell type implicated are microglia - the resident immune cells of the brain. While there is substantial evidence for a role of microglia from animal models of depression (e.g. chronic stress), data on human microglia is limited. Recent advances in induced pluripotent stem cell (iPSC) research provide new possibilities to study human microglia in vitro. In this study, we generated iPSC lines of patients with major depressive disorder (MDD) and healthy controls (HC) selected from the extreme ends of the genetic risk spectrum to study a potential influence of genetic risk for depression on microglial function and their responses to relevant environmental stimuli.
Peripheral blood mononuclear cells for iPSC generation were selected from unrelated individuals from the German FOR2107 cohort. Patients with recurrent MDD and HC were selected from the tail-ends of the distribution of polygenic risk scores (PRS) for depression, based on the genome-wide association study (GWAS) by Howard et al. (2019). Additionally, only donors with at least one first degree relative with MDD or no family history of psychiatric disorders were selected in the high and low PRS group, respectively. iPSC lines were generated for six male donors (n = 3 per group) at the Cell Programming Core Facility of the University of Bonn and will be differentiated into iPSC-derived microglia (iMG) in the upcoming months. In pilot experiments, sequential differentiation of iPSCs into primitive macrophage precursors and iMG was established using a control iPSC line (HPSI0514i-letw_5). Cell-type identity was monitored throughout differentiation using flow cytometry, immunocytochemistry and transcriptome analysis (3’mRNA-Seq). Furthermore, iMG were stimulated with lipopolysaccharide (LPS) or dexamethasone (Dex) to study inflammatory and glucocorticoid (“stress”) signalling.
Results from pilot experiments indicate successful differentiation from iPSCs into macrophage precursors and iMG, based on the expression of macrophage/microglia-specific proteins and gene expression signatures. Transcriptome analysis further revealed that 217 out of 269 GWAS candidate genes for depression are expressed in at least one of the differentiation stages. When stimulated with LPS or Dex, iMG showed differential expression of inflammatory and glucocorticoid-response genes, respectively. For example, FKBP5, a negative regulator of glucocorticoid signalling and known candidate gene to mediate interactions between stress and depression liability, was the most strongly upregulated gene in Dex-treated iMG. Additionally, secretion of pro-inflammatory cytokines by LPS-treated iMG confirmed a functional response to inflammatory stimulation.
In summary, these preliminary analyses suggest that iMG are a valid model to study inflammatory and glucocorticoid signalling. The generation of iMG from our newly established MDD and HC cell lines will provide a valuable tool to test whether genetic risk for depression affects human microglia function and enable analyses of gene-environment interactions (e.g. “stress”) in a defined cellular model.
Bipolar disorder (BD) is a severe and highly heritable psychiatric disorder, characterized by recurrent episodes of (hypo)mania and depression. Recent genome-wide association studies (GWAS) support a ...strong polygenic influence. However, its impact on neuronal development and function remains largely unknown. Therefore, we generated induced pluripotent stem cells (iPSCs) from genetically characterized patients with BD type 1 (BD1) and healthy controls (HC) with a high or low polygenic risk score (PRS) for BD1, respectively. Differentiation of these iPSC-lines into neural progenitor cells (NPCs) enables studying the combined effect of common variants in a model of early neurodevelopment.
Peripheral blood mononuclear cells for iPSC generation were selected from unrelated male individuals from the German FOR2107 cohort (https://for2107.de/). BD1 patients with the highest and HCs with the lowest PRS for BD1 (Stahl et al., 2019; PRS-CS) were screened for the absence of copy number variants (CNVs) associated with BD or schizophrenia (Green et. al, 2016; Marshall et al, 2017; cnvPartition). From this selection, 10 donors per group were whole genome sequenced using an Illumina NovaSeq 6000. To limit a potential influence of rare deleterious variants on cellular functions, carriers of variants identified in 20 previously published BD sequencing studies were excluded (MAF 20; variant not present in BD1 patients and HCs). iPSC lines were generated and quality controlled for six donors (n = 3 per group) and differentiated into cortical NPCs. Cells were harvested at day 0, 12, 22 and 32 for transcriptome analysis (n = 2 per donor and timepoint). 3’mRNA-sequencing was performed at the NGS Core Facility of the University of Bonn using the Lexogen QuantSeq 3’mRNA-Seq Library Prep Kit. Data was analysed using Partek Flow Genomic Analysis Software. Differentially expressed genes (DEGs) were identified using DESeq2 and used for subsequent gene set enrichment analysis.
During the selection process, a total of 13 donors were excluded based on the presence of either CNVs (n = 1) or rare variants (n = 12) associated with BD and/or schizophrenia, highlighting the value of thorough genetic characterization of donors when studying the effect of polygenic risk in iPSC models. The generated iPSC-lines could successfully be differentiated into NPCs without obvious alterations in morphology or neuronal development between BD1 and HC cells. Analysis of transcriptome data revealed that the different time points during differentiation explained most of the variance between samples. However, a clear segregation of BD1 and HC cells was observed in fully differentiated NPCs (day 32). At this stage, DESeq2 identified >1000 significant DEGs between BD1 and HC, several of which overlap with candidate genes identified in recent GWAS and TWAS for BD (e.g. FURIN, LMAN2L, TRANK1). Gene set enrichment analysis of DEGs at day 32 revealed pathways such as “Hippo signaling” and “MAP kinase activity”.
In summary, these preliminary findings suggest that the polygenic risk for BD1 alone influences expression of genes related to cellular development and intracellular signaling during early neurodevelopment. If validated in future experiments, these findings could provide valuable insight into the genes and mechanisms that common risk variants converge on during early BD pathogenesis.
Major depressive disorder (MDD) is a complex multifactorial condition with an estimated heritability of 40%, characterized by episodes of depressed mood, loss of interest and additional symptoms such ...as weight changes, sleep disturbances and fatigue. Both a high relapse and recurrence risk of MDD are known from epidemiological studies, however, biomarkers that could facilitate early detection and prediction of prognosis are lacking. DNA methylation (DNAm) has been suggested as a potential molecular marker for disorder states and traits due to its capacity to integrate both genetic and environmental signals into an epigenetic memory. In a sample of individuals with a lifetime diagnosis of MDD and healthy controls, we here performed a longitudinal analysis of blood-based DNAm profiles with regard to case-control status and longitudinal readouts, including the number of depressive episodes, number of hospitalizations and phase of illness at measurement.
For 185 MDD cases and 188 age- and sex-matched healthy controls drawn from the deeply phenotyped German FOR2107 cohort, DNAm at baseline and at a two-year follow-up study visit was profiled with the Infinium MethylationEPIC BeadChip in peripheral blood. Data quality control and stratified quantile normalization of methylation signals were conducted in R using the minfi and ewastools packages, resulting in a longitudinal analysis sample of 178 MDD cases and 178 healthy controls with two measurements each. Differential methylation was examined across more than 760k CpG sites with linear mixed models using the limma package, including proband identity as a random effect. For each independent variable of interest, a separate model was fitted. As fixed effect covariates, sex, age, cell type composition estimated with the Houseman approach, ten genotyping-based principal components (PC) as well as ten methylation control-probe PCs were included in each model. Associations with p < 9e-8 were considered methylome-wide significant.
In the analysis of case-control status, significant differential methylation was detected at four CpG sites, including hypomethylation of cg04847273, which is located within the GABRD gene encoding a GABA receptor subunit. Regarding the number of depressive episodes and hospitalizations, 13 and 40 CpG sites, respectively, showed significant differential methylation. When comparing different categories reflecting phase of illness (acute episode, partial remission, full remission, healthy), significant differential methylation was visible between samples of MDD cases in full remission and healthy controls at two CpG sites.
To the best of our knowledge, our study represents one of the largest methylome-wide longitudinal investigations of MDD so far. The detected differences in blood-based DNAm profiles provide a promising starting point for the identification of trait- and state-dependent biomarkers in MDD. The hypomethylation within GABRD appears to be particularly interesting, as it might be related to GABAergic dysregulation in mood disorders implicated by previous studies. Larger sample sizes and a higher number of longitudinal measurements per individual are required to increase statistical power, and any identified associations should be replicated in independent cohorts.
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