Polygenic risk for schizophrenia converges on alternative polyadenylation as molecular mechanism underlying synaptic impairment.

Schizophrenia (SCZ) is a genetically heterogenous psychiatric disorder of highly polygenic nature. Correlative evidence from genetic studies indicate that the aggregated effects of distinct genetic risk factor combinations found in each patient converge onto common molecular mechanisms. To prove this on a functional level, we employed a reductionistic cellular model system for polygenic risk by differentiating induced pluripotent stem cells (iPSCs) from 104 individuals with high polygenic risk load and controls into cortical glutamatergic neurons (iNs). Multi-omics profiling identified widespread differences in alternative polyadenylation (APA) in the 3' untranslated region of many synaptic transcripts between iNs from SCZ patients and healthy donors. On the cellular level, 3'APA was associated with a reduction in synaptic density of iNs. Importantly, differential APA was largely conserved between postmortem human prefrontal cortex from SCZ patients and healthy donors, and strongly enriched for transcripts related to synapse biology. 3'APA was highly correlated with SCZ polygenic risk and affected genes were significantly enriched for SCZ associated common genetic variation. Integrative functional genomic analysis identified the RNA binding protein and SCZ GWAS risk gene PTBP2 as a critical trans-acting factor mediating 3'APA of synaptic genes in SCZ subjects. Functional characterization of PTBP2 in iNs confirmed its key role in 3'APA of synaptic transcripts and regulation of synapse density. Jointly, our findings show that the aggregated effects of polygenic risk converge on 3'APA as one common molecular mechanism that underlies synaptic impairments in SCZ.

High-throughput screening of glucocorticoid-induced enhancer activity reveals mechanisms of stress-related psychiatric disorders.

Exposure to stressful life events increases the risk for psychiatric disorders. Mechanistic insight into the genetic factors moderating the impact of stress can increase our understanding of disease processes. Here, we test 3,662 single nucleotide polymorphisms (SNPs) from preselected expression quantitative trait loci in massively parallel reporter assays to identify genetic variants that modulate the activity of regulatory elements sensitive to glucocorticoids, important mediators of the stress response. Of the tested SNP sequences, 547 were located in glucocorticoid-responsive regulatory elements of which 233 showed allele-dependent activity. Transcripts regulated by these functional variants were enriched for those differentially expressed in psychiatric disorders in the postmortem brain. Phenome-wide Mendelian randomization analysis in 4,439 phenotypes revealed potentially causal associations specifically in neurobehavioral traits, including major depression and other psychiatric disorders. Finally, a functional gene score derived from these variants was significantly associated with differences in the physiological stress response, suggesting that these variants may alter disease risk by moderating the individual set point of the stress response.

Massively parallel functional dissection of schizophrenia-associated noncoding genetic variants.

Schizophrenia (SCZ) is a highly heritable mental disorder with thousands of associated genetic variants located mostly in the noncoding space of the genome. Translating these associations into insights regarding the underlying pathomechanisms has been challenging because the causal variants, their mechanisms of action, and their target genes remain largely unknown. We implemented a massively parallel variant annotation pipeline (MVAP) to perform SCZ variant-to-function mapping at scale in disease-relevant neural cell types. This approach identified 620 functional variants (1.7%) that operate in a highly developmental context and neuronal-activity-dependent manner. Multimodal integration of epigenomic and CRISPRi screening data enabled us to link these functional variants to target genes, biological processes, and ultimately alterations of neuronal physiology. These results provide a multistage prioritization strategy to map functional single-nucleotide polymorphism (SNP)-to-gene-to-endophenotype relations and offer biological insights into the context-dependent molecular processes modulated by SCZ-associated genetic variation.

Cell type and condition specific functional annotation of schizophrenia associated non-coding genetic variants.

Schizophrenia (SCZ) is a highly polygenic disease and genome wide association studies have identified thousands of genetic variants that are statistically associated with this psychiatric disorder. However, our ability to translate these associations into insights on the disease mechanisms has been challenging since the causal genetic variants, their molecular function and their target genes remain largely unknown. In order to address these questions, we established a functional genomics pipeline in combination with induced pluripotent stem cell technology to functionally characterize ~35,000 non-coding genetic variants associated with schizophrenia along with their target genes. This analysis identified a set of 620 (1.7%) single nucleotide polymorphisms as functional on a molecular level in a highly cell type and condition specific fashion. These results provide a high-resolution map of functional variant-gene combinations and offer comprehensive biological insights into the developmental context and stimulation dependent molecular processes modulated by SCZ associated genetic variation.

Calcium Channel Subunit α2δ4 Is Regulated by Early Growth Response 1 and Facilitates Epileptogenesis.

Transient brain insults, including status epilepticus (SE), can trigger a period of epileptogenesis during which functional and structural reorganization of neuronal networks occurs resulting in the onset of focal epileptic seizures. In recent years, mechanisms that regulate the dynamic transcription of individual genes during epileptogenesis and thereby contribute to the development of a hyperexcitable neuronal network have been elucidated. Our own results have shown early growth response 1 (Egr1) to transiently increase expression of the T-type voltage-dependent Ca2+ channel (VDCC) subunit CaV3.2, a key proepileptogenic protein. However, epileptogenesis involves complex and dynamic transcriptomic alterations; and so far, our understanding of the transcriptional control mechanism of gene regulatory networks that act in the same processes is limited. Here, we have analyzed whether Egr1 acts as a key transcriptional regulator for genes contributing to the development of hyperexcitability during epileptogenesis. We found Egr1 to drive the expression of the VDCC subunit α2δ4, which was augmented early and persistently after pilocarpine-induced SE. Furthermore, we show that increasing levels of α2δ4 in the CA1 region of the hippocampus elevate seizure susceptibility of mice by slightly decreasing local network activity. Interestingly, we also detected increased expression levels of Egr1 and α2δ4 in human hippocampal biopsies obtained from epilepsy surgery. In conclusion, Egr1 controls the abundance of the VDCC subunits CaV3.2 and α2δ4, which act synergistically in epileptogenesis, and thereby contributes to a seizure-induced "transcriptional Ca2+ channelopathy."SIGNIFICANCE STATEMENT The onset of focal recurrent seizures often occurs after an epileptogenic process induced by transient insults to the brain. Recently, transcriptional control mechanisms for individual genes involved in converting neurons hyperexcitable have been identified, including early growth response 1 (Egr1), which activates transcription of the T-type Ca2+ channel subunit CaV3.2. Here, we find Egr1 to regulate also the expression of the voltage-dependent Ca2+ channel subunit α2δ4, which was augmented after pilocarpine- and kainic acid-induced status epilepticus. In addition, we observed that α2δ4 affected spontaneous network activity and the susceptibility for seizure induction. Furthermore, we detected corresponding dynamics in human biopsies from epilepsy patients. In conclusion, Egr1 orchestrates a seizure-induced "transcriptional Ca2+ channelopathy" consisting of CaV3.2 and α2δ4, which act synergistically in epileptogenesis.

Dysfunction of spatacsin leads to axonal pathology in SPG11-linked hereditary spastic paraplegia.

Hereditary spastic paraplegias are a group of inherited motor neuron diseases characterized by progressive paraparesis and spasticity. Mutations in the spastic paraplegia gene SPG11, encoding spatacsin, cause an autosomal-recessive disease trait; however, the precise knowledge about the role of spatacsin in neurons is very limited. We for the first time analyzed the expression and function of spatacsin in human forebrain neurons derived from human pluripotent stem cells including lines from two SPG11 patients and two controls. SPG11 patients'-derived neurons exhibited downregulation of specific axonal-related genes, decreased neurite complexity and accumulation of membranous bodies within axonal processes. Altogether, these data point towards axonal pathologies in human neurons with SPG11 mutations. To further corroborate spatacsin function, we investigated human pluripotent stem cell-derived neurons and mouse cortical neurons. In these cells, spatacsin was located in axons and dendrites. It colocalized with cytoskeletal and synaptic vesicle (SV) markers and was present in synaptosomes. Knockdown of spatacsin in mouse cortical neurons evidenced that the loss of function of spatacsin leads to axonal instability by downregulation of acetylated tubulin. Finally, time-lapse assays performed in SPG11 patients'-derived neurons and spatacsin-silenced mouse neurons highlighted a reduction in the anterograde vesicle trafficking indicative of impaired axonal transport. By employing SPG11 patient-derived forebrain neurons and mouse cortical neurons, this study provides the first evidence that SPG11 is implicated in axonal maintenance and cargo trafficking. Understanding the cellular functions of spatacsin will allow deciphering mechanisms of motor cortex dysfunction in autosomal-recessive hereditary spastic paraplegia.

Antidepressants as add-on treatment to antipsychotics for people with schizophrenia and pronounced negative symptoms: a systematic review of randomized trials.

The aim of our meta-analysis was to review the evidence base for the efficacy and safety of antipsychotic and antidepressant combinations in the treatment of the negative symptoms of schizophrenia and schizophrenia-like psychoses. Randomized controlled trials comparing the combination of antidepressants and antipsychotics with antipsychotics alone for patients with pronounced negative symptoms in schizophrenia were searched for by accessing the register of randomized controlled trials of the Cochrane Schizophrenia group. The studies identified were independently inspected and their quality assessed by two reviewers. The principal outcome of interest was the reduction of negative symptoms. Dichotomous data were analyzed using the relative risk and continuous data were analyzed using standardized mean differences, both specified with 95% confidence intervals. It was possible to include seven trials (n = 202) examining antidepressants as add-on to antipsychotics in this review. Except for one study, all included studies used first generation antipsychotics. While there was often merely a trend in favour of augmentation of antipsychotics with antidepressants in the small single studies, the meta-analytic combination resulted in a statistically significant superiority in the outcome reduction of negative symptoms as a whole. Statistically significant differences between groups in terms of specific subscores of the SANS were found, but the results were inconsistent. The combination of antipsychotics and antidepressants may be more effective in treating negative symptoms of schizophrenia than antipsychotics alone, but this finding needs to be corroborated by further large trials.

["Family members inform family members" - family members as group moderators for psychoeducational groups in schizophrenia]. / "Angehörige informieren Angehörige" - Angehörige als Gruppenleiter für psychoedukative Gruppen bei Schizophrenie.

OBJECTIVES: To train interested and capable family members as group moderators of psychoeducational groups for family members in schizophrenia. METHOD: Development and evaluation of a curriculum consisting of 5 separate steps: participating in a psychoeducational group, participating in training-workshops, conducting psychoeducational group sessions with professional co-moderation, independently conducting psychoeducational group sessions, recruiting of future group moderators. RESULTS: Step 1, 2 and 3: statistically significant knowledge increase about schizophrenia, changed concept of illness. DISCUSSION: The 5-step curriculum appears to be a useful instrument for training family members as group moderators of psychoeducational groups for family members in schizophrenia.

Peer-to-peer psychoeducation in schizophrenia: a new approach.

OBJECTIVE: To evaluate the feasibility of the first peer-to-peer psychoeducation program in schizophrenia. METHOD: We developed a 5-step curriculum for structured training of peer moderators. In step 1, peer moderators participate in regular psychoeducation, and in step 2, they participate in workshops on knowledge about schizophrenia and moderation techniques. In step 3, peer moderators conduct peer-to-peer groups in the presence of a mental health professional, and in step 4, they conduct the groups independently with regular supervision. Further peer moderators are recruited in step 5. Psychoeducation by trained peer moderators comprises 8 60-minute group sessions (warm-up, symptoms, diagnosis, causes, medication, psychosocial therapy, warning signs, coping with schizophrenia) with 6 to 10 patients per group. The feasibility of the 5-step curriculum was evaluated by conducting a pilot study of 7 peer groups with 2 peer moderators. Evaluation of peer-moderated groups was done from January 2003 to July 2004 using inpatients of a university hospital who had schizophrenia or schizoaffective disorder according to ICD-10. The primary outcomes of interest were change in knowledge and concept of illness from baseline to endpoint. RESULTS: Two peer moderators conducted psychoeducational groups with a total of 49 patients in the presence of a physician (step 3). On the whole, conduction of peer-moderated groups worked well. Knowledge of illness increased significantly (N = 44, p < .001), and concept of illness changed significantly in 3 subscales: trust in physician (N = 40, p = .002) and trust in medication (N = 40, p = .001) increased, and negative treatment expectations decreased (N = 40, p = .001). Subjective assessments of peer moderators by participating patients were positive. CONCLUSION: First results suggest that peer-to-peer psychoeducation in schizophrenia according to the 5-step curriculum is feasible and may be comparable to professional psychoeducation in regard to short-term outcomes.