Common changes in rat cortical gene expression after antidepressant drug treatment: Impacts on metabolism of polyamines, mRNA splicing, regulation of RAS by GAPs, neddylation and GPCR ligand binding

This study sought to identify pathways affected by rat cortical RNA that were changed after treatment with fluoxetine or imipramine. We measured levels of cortical RNA in male rats using GeneChip® Rat Exon 1.0 ST Array after treatment with vehicle (0.9% NaCl), fluoxetine (10 mg/kg/day) or imipramine (20 mg/kg/day) for 28 days. Levels of coding and non-coding RNA in vehicle treated rats were compared to those in treated rats using ANOVA in JMP Genomics 13 and the Panther Gene Ontology Classification System was used to identify pathways involving the changed RNAs. 18,876 transcripts were detected; there were highly correlated changes in 1010 levels of RNA after both drug treatments that would principally affect the metabolism of polyamines, mRNA splicing, regulation of RAS by GAPs, neddylation and GPCR ligand binding. Using our previously published data, we compared changes in transcripts after treatment with antipsychotic and mood stabilising drugs. Our study shows there are common, correlated, changes in coding and non-coding RNA in the rat cortex after treatment with fluoxetine or imipramine; we propose the pathways affected by these changes are involved in the therapeutic mechanisms of action of antidepressant drugs.</p

Additional file 2: Figure S1. of Validating reference genes using minimally transformed qpcr data: findings in human cortex and outcomes in schizophrenia

Examples of plate wide melt curves for GAPDH, PPIA, SNCA, NOL 9, TFB1M and SKP 1. (DOCX 3905 kb

Additional file 4: Table S3. of Validating reference genes using minimally transformed qpcr data: findings in human cortex and outcomes in schizophrenia

The relationships between levels of cortical mRNA and donor age, post-mortem interval (PMI), CNS pH, duration of illness (DI) and RNA integrity number (RIN). Relationships where the regression line deviated significantly from a slope of zero are bolded and in italics. (DOCX 24 kb

Additional file 1: Table S1. of Validating reference genes using minimally transformed qpcr data: findings in human cortex and outcomes in schizophrenia

Primer sequences and accession numbers for the primers used in qPCR. (DOCX 15 kb

Altered M1 Muscarinic Acetylcholine Receptor (CHRM1)-Gαq/11 Coupling in a Schizophrenia Endophenotype

Alterations in muscarinic acetylcholine receptor (CHRM) populations have been implicated in the pathology of schizophrenia. Here we have assessed whether the receptor function of the M1 subtype (CHRM1) is altered in a sub-population of patients with schizophrenia, defined by marked (60–80%) reductions in cortical [3H]-pirenzepine (PZP) binding, and termed ‘muscarinic receptor-deficit schizophrenia’ (MRDS). Using a [35S]-GTPγS-Gαq/11 immunocapture method we have assessed whether CHRM1 signalling in human cortex (Brodmann area 9 (BA9)) is altered in post mortem tissue from a MRDS group compared with a subgroup of patients with schizophrenia displaying normal PZP binding, and controls with no known history of psychiatric or neurological disorders. The CHRM agonist (oxotremorine-M) and a CHRM1-selective agonist (AC-42) increased Gαq/11-[35S]-GTPγS binding, with AC-42 producing responses that were ~50% of those maximally evoked by the full agonist, oxotremorine-M, in control and subgroups of patients with schizophrenia. However, the potency of oxotremorine-M to stimulate Gαq/11-[35S]-GTPγS binding was significantly decreased in the MRDS group (pEC50 (M)=5.69±0.16) compared with the control group (6.17±0.10) and the non-MRDS group (6.05±0.07). The levels of Gαq/11 protein present in BA9 did not vary with diagnosis. Maximal oxotremorine-M-stimulated Gαq/11-[35S]-GTPγS binding in BA9 membranes was significantly increased in the MRDS group compared with the control group. Similar, though non-statistically significant, trends were observed for AC-42. These data provide evidence that both orthosterically and allosterically acting CHRM agonists can stimulate a receptor-driven functional response ([35S]-GTPγS binding to Gαq/11) in membranes prepared from post mortem human dorsolateral prefrontal cortex of patients with schizophrenia and controls . Furthermore, in a subgroup of patients with schizophrenia displaying markedly decreased PZP binding (MRDS) we have shown that although agonist potency may decrease, the efficacy of CHRM1-Gαq/11 coupling increases, suggesting an adaptative change in receptor-G protein coupling efficiency in this endophenotype of patients with schizophrenia

The use of a gene expression signature and connectivity map to repurpose drugs for bipolar disorder

<p><b>Objectives:</b> To create a gene expression signature (GES) to represent the biological effects of a combination of known drugs for bipolar disorder (BD) on cultured human neuronal cells (NT2-N) and rat brains, which also has evidence of differential expression in individuals with BD. To use the GES to identify new drugs for BD using Connectivity Map (CMap).<b>Methods:</b> NT2-N (<i>n</i> = 20) cells and rats (<i>n</i> = 8) were treated with a BD drug combination (lithium, valproate, quetiapine and lamotrigine) or vehicle for 24 and 6 h, respectively. Following next-generation sequencing, the differential expression of genes was assessed using edgeR in R. The derived GES was compared to differentially expressed genes in post-mortem brains of individuals with BD. The GES was then used in CMap analysis to identify similarly acting drugs.<b>Results:</b> A total of 88 genes showed evidence of differential expression in response to the drug combination in both models, and therefore comprised the GES. Six of these genes showed evidence of differential expression in post-mortem brains of individuals with BD. CMap analysis identified 10 compounds (camptothecin, chlorambucil, flupenthixol, valdecoxib, rescinnamine, GW-8510, cinnarizine, lomustine, mifepristone and nimesulide) acting similarly to the BD drug combination.<b>Conclusions:</b> This study shows that GES and CMap can be used as tools to repurpose drugs for BD.</p