Impact of haloperidol and risperidone on gene expression profile in the rat cortex

Inhibitory and Agonistic Autoantibodies Directed Against the β2-Adrenergic Receptor in Pseudoexfoliation Syndrome and Glaucoma

Pseudoexfoliation syndrome (PEXS) and glaucoma (PEXG) are assumed to be caused by a generalized elastosis leading to the accumulation of PEX material in ocular as well as in extraocular tissues. The exact pathophysiology of PEXS is still elusive. PEXG, the most common type of secondary open-angle glaucoma (OAG), is characterized by large peaks of intraocular pressure (IOP) with a progressive loss of the visual field. Agonistic autoantibodies (agAAbs) against the β₂-adrenergic receptor (AR) have been shown to be present in sera of patients with primary and secondary OAG and ocular hypertension and are seemingly linked to IOP. In the present study, we investigated the autoantibodies directed against the β₂-AR in sera of patients with PEXS and PEXG. We recruited 15, 10, and 15 patients with PEXG, PEXS, and primary OAG, respectively. Ten healthy individuals served as controls. All patients underwent standard ophthalmological examination with Octopus G1 perimetry. agAAbs prepared from serum samples were analyzed in a rat cardiomyocyte-based bioassay for the presence of agAAbs. We identified the interacting loop of the β₂-AR and the immunoglobulin G (IgG) subclasses using synthetic peptides corresponding to the extracellular loops of the receptors and enzyme-linked immunosorbent assay, respectively. None of the controls were β₂-agAAb-positive (0.2 ± 0.5 U). No β₂-agAAbs (0.2 ± 0.4 U), but inhibitory β₂-AAbs were observed in 80% of the patients that partially blocked the drug-induced β₂-adrenergic stimulation; 5.8 ± 1.7 U vs. 11.1 ± 0.9 U for clenbuterol in the absence and the presence of sera from patients with PEXS, respectively. Epitope analyses identified the third extracellular loop of the β₂-AR as the target of the inhibitory β₂-AAbs, being of IgG3 subtype in PEXS patients. In contrast, patients with PEXG showed β₂-agAAbs (5.6 ± 0.9 U), but no inhibitory ones. The β₂-agAAbs levels of patients with PEXG and primary OAG patients (3.9 ± 2.8 U; p > 0.05) were at a similar level. In two cases of PEXG, the β₂-agAAbs exert synergistic effects with clenbuterol. The activity increased from 11.5 ± 0.3 (clenbuterol only) to 16.3 ± 0.9 U. As autoimmune mechanisms were reportedly involved in the pathogenesis of glaucoma, agonistic and inhibitory β₂-AAbs seem to be a part of this multifactorial interplay.

HTR1A, HTR1B, HTR2A, HTR2C and HTR6 Gene Polymorphisms and Extrapyramidal Side Effects in Haloperidol-Treated Patients with Schizophrenia

Schizophrenia is a serious, chronic psychiatric disorder requiring lifelong treatment. Extrapyramidal side effects (EPS) are common adverse reactions to antipsychotic medications. In addition to the dopaminergic system, serotonergic mechanisms, including serotonin (5-HT) receptors, might be involved in EPS development. This study aimed to examine molecular associations of HTR1A, HTR1B, HTR2A, HTR2C and HTR6 gene polymorphisms with acute EPS in 229 male schizophrenia patients, following two weeks of haloperidol monotherapy. The Simpson-Angus Rating Scale for Extrapyramidal Side Effects (SAS), Barnes Akathisia Rating Scale (BARS) and Extrapyramidal Symptom Rating Scale (ESRS) were used to evaluate EPS severity. Genotyping was performed using real-time PCR, following extraction of blood DNA. Significant acute EPS appeared in 48.03% of schizophrenia patients. For the rs13212041 HTR1B gene polymorphism, affecting microRNA regulation of HTR1B gene expression, a higher frequency of TT carriers was found among haloperidol-treated patients with akathisia when compared to the group without akathisia symptoms. In comparison to C-allele carriers, patients carrying the TT genotype had higher akathisia severity, as determined by the SAS, BARS and ESRS scales. These molecular findings suggest potential involvement of 5-HT_1B receptors in akathisia development following haloperidol treatment, as well as possible epigenetic mechanisms of serotonergic modulation associated with antipsychotic-induced EPS.

Function of Cathepsin K in the Central Nervous System of Male Mice is Independent of Its Role in the Thyroid Gland

Cathepsin K deficiency in male mice (Ctsk^-/-) results in decreased numbers of hippocampal astrocytes and altered neuronal patterning as well as learning and memory deficits. Additionally, cathepsin K carries essential roles in the thyroid gland where it contributes to the liberation of thyroid hormones (TH). Because TH are essential for brain development, in particular for the cerebellum, we investigated whether cathepsin K's function in the thyroid is directly linked to the brain phenotype of Ctsk^-/- mice. Serum levels of thyroid stimulating hormone, brain concentrations of free TH, and deiodinase 2 (Dio2) activity in brain parenchyma as well as cerebellar development were comparable in Ctsk^-/- and WT animals, suggesting regular thyroid states and TH metabolism. Despite unaltered transcript levels, protein expression of two TH transporters was enhanced in specific brain regions in Ctsk^-/- mice, suggesting altered TH supply to these regions. Thyrotropin releasing hormone (Trh) mRNA levels were enhanced threefold in the hippocampus of Ctsk^-/- mice. In the striatum of Ctsk^-/- mice the mRNA for Dio2 and hairless were approximately 1.3-fold enhanced, while mRNA levels for monocarboxylate transporter 8 and Trh were reduced to 60% and 40%, respectively, pointing to altered striatal physiology. We conclude that the role of cathepsin K in the thyroid gland is not directly associated with its function in the central nervous system (CNS) of mice. Future studies will show whether the brain region-specific alterations in Trh mRNA may eventually result in altered neuroprotection that could explain the neurobehavioral defects of Ctsk^-/- mice.

Autoantibodies Activating the β2-Adrenergic Receptor Characterize Patients With Primary and Secondary Glaucoma

Recently, agonistic autoantibodies (agAAb) activating the β2-adrenergic receptor were detected in primary open-angle glaucoma (POAG) or ocular hypertension (OHT) patients and were linked to intraocular pressure (IOP) (1). The aim of the present study was to quantify β2-agAAb in the sera of glaucoma suspects and patients with primary and secondary glaucoma. Patients with OHT (n = 33), pre-perimetric POAG (pre-POAG; n = 11), POAG (n = 28), and 11 secondary OAG (SOAG) underwent ophthalmological examinations including examinations with Octopus G1 perimetry and morphometry. Twenty-five healthy individuals served as controls. Serum-derived IgG samples were analyzed for β2-agAAb using a functional bioassay. The beat-rate-increase of spontaneously beating cultured neonatal rat cardiomyocytes was monitored with 1.6 beats/15 s as cut-off. None of the sera of normal subjects showed β2-agAAb. In POAG or OHT patients increased beating rates of 4.1 ± 2.2 beats/15 s, and 3.7 ± 2.8 beats/15 s were detected (p > 0.05). Glaucoma patients with (POAG) and without perimetric (pre-POAG) defects did not differ (pre-POAG 4.4 ± 2.6 beats/15 s, POAG 4.1 ± 2.0 beats/15 s, p > 0.05). Patients with SOAG yielded mean beating rates of 4.7 ± 1.7 beats/15 s (p > 0.05). β2-agAAb were seen in 73% of OHT, 82% of pre-POAG, 82% of POAG, and 91% SOAG patients (p < 0.001). Clinical data did not correlate with beating rate (p > 0.05). The robust β2-agAAb seropositivity in patients with OHT, pre-POAG, POAG, and SOAG suggest a primary common role for β2-agAAb starting early in glaucoma pathophysiology and turned out to be a novel marker identifying all patients with increased IOP independent of glaucoma stage and entity.

Changed frontal pole gene expression suggest altered interplay between neurotransmitter, developmental, and inflammatory pathways in schizophrenia

Schizophrenia (Sz) probably occurs after genetically susceptible individuals encounter a deleterious environmental factor that triggers epigenetic mechanisms to change CNS gene expression. To determine if omnibus changes in CNS gene expression are present in Sz, we compared mRNA levels in the frontal pole (Brodmann’s area (BA) 10), the dorsolateral prefrontal cortex (BA 9) and cingulate cortex (BA 33) from 15 subjects with Sz and 15 controls using the Affymetrix™ Human Exon 1.0 ST Array. Differences in mRNA levels (±≥20%; p < 0.01) were identified (JMP Genomics 5.1) and used to predict pathways and gene x gene interactions that would be affected by the changes in gene expression using Ingenuity Pathway Analysis. There was significant variation in mRNA levels with diagnoses for 566 genes in BA 10, 65 genes in BA 9 and 40 genes in BA 33. In Sz, there was an over-representation of genes with changed expression involved in inflammation and development in BA 10, cell morphology in BA 9 and amino acid metabolism and small molecule biochemistry in BA 33. Using 94 genes with altered levels of expression in BA 10 from subjects with Sz, it was possible to construct an interactome of proven direct gene x gene interactions that was enriched for genes in inflammatory, developmental, oestrogen, serotonergic, cholinergic and NRG1 regulated pathways. Our data shows complex, regionally specific changes in cortical gene expression in Sz that are predicted to affect homeostasis between biochemical pathways already proposed to be important in the pathophysiology of the disorder.

Anterior brain regions exhibit significant amounts of differentially-expressed genes which might cause dysfunction in schizophrenia. It’s thought that schizophrenia occurs when environmental factors trigger gene expression changes and downstream effects in the human brain, though this is not fully understood. An Australian research group led by Brian Dean, from the Florey Institute of Neuroscience and Mental Health, conducted a post-mortem human brain study in which they compared gene expression between 15 schizophrenia patients and 15 controls. They found 566 instances of altered gene expression in the most frontal part of the brain, Brodmann Area 10, and fewer changes in proximal regions. These are brain areas known to mediate schizophrenia-related traits and the changes in gene expression in these areas will affect a range of essential biological pathways. The group also found 97 differentially-expressed genes that have been shown to directly interact with each. This study paints a complex picture of the causes of schizophrenia but suggests modern technologies can help unravel these complexities.

Agonistic Autoantibodies to the β2-Adrenergic Receptor Involved in the Pathogenesis of Open-Angle Glaucoma

Glaucoma is a frequent ocular disease that may lead to blindness. Primary open-angle glaucoma (POAG) and ocular hypertension (OHT) are common diseases with increased intraocular pressure (IOP), which are mainly responsible for these disorders. Their pathogenesis is widely unknown. We screened the sera of patients with POAG and OHT for the prevalence of autoantibodies (AAb) against G protein-coupled receptors (GPCRs) in comparison to controls. Employing frequency modulation of spontaneously contracting neonatal rat cardiomyocytes in vitro, agonistic GPCR AAb were to be detected in roughly 75% of the patients with POAG and OHT, however, not in controls. Using inhibitory peptides the AAb’ target was identified as β2 adrenergic receptor (β2AR). The AAb interact with the second extracellular loop of β2AR. The peptides 181–187 and 186–192 were identified as binding sites of the AAb within the extracellular loop II. The binding of the AAb to β2ARs was verified by surface-plasmon-resonance analysis. The isotype of the AAb was (immunoglobulin) IgG3. In an additional pilot principal-of-proof study, including four patients with POAG, the removal of the AAb against the β2AR and other immunoglobulins G by immunoadsorption resulted in a transient reduction of IOP. These findings might indicate a possible role of agonistic AAb directed against β2ARs in the dynamics of aqueous humor and might support a contribution of adaptive autoimmunity in the etiopathogenesis of POAG and OHT.

Subchronic olanzapine exposure leads to increased expression of myelination-related genes in rat fronto-medial cortex

Schizophrenia is a psychotic disorder with severe and disabling symptoms, such as hallucinations, delusions, blunted affect and social withdrawal. The neuropathology remains elusive, but disturbances in immunity-related processes, neuronal connectivity and myelination have consistently been linked to schizophrenia. Antipsychotic drugs can be efficient in reducing symptoms, acting primarily on the dopamine system, but additional biological targets are likely to exist. Here we have screened for novel mechanisms of action in an animal model, using adult rats exposed to long-acting olanzapine, achieving stable and clinically relevant antipsychotic drug concentrations. By microarray-based examination of global gene expression in the fronto-medial cortex, at the single gene- and gene-set level, we observed downregulation of two neuropeptide-encoding genes, Vgf and Cort (fold change -1,25 and -1,48, respectively) in response to olanzapine exposure. Furthermore, we demonstrated significant upregulation of five out of ~2000 GO predefined gene sets after olanzapine exposure. Strikingly, all were linked to myelination and oligodendrocyte development; "Ensheathment of neurons", "Axon ensheathment", "Myelination", "Myelin sheath" and "Oligodendrocyte development" (FDR-values < 25). Sixteen of the leading edge genes in these gene sets were analysed independently by qPCR, of which 11 genes displayed significant upregulation, including Plp1, Mal, Mag and Cnp (fold change: 1,30, 1,50, 1,30 and 1,15, respectively). Several of the upregulated genes (e.g. MAG, MAL and CNP) have previously been reported as downregulated in post-mortem brain samples from schizophrenia patients. Although caution needs to be taken when extrapolating results from animal studies to humans, the data suggest a role for olanzapine in alleviating myelination-related dysfunction in schizophrenia.

Haloperidol induces pharmacoepigenetic response by modulating miRNA expression, global DNA methylation and expression profiles of methylation maintenance genes and genes involved in neurotransmission in neuronal cells

Introduction

Haloperidol has been extensively used in various psychiatric conditions. It has also been reported to induce severe side effects. We aimed to evaluate whether haloperidol can influence host methylome, and if so what are the possible mechanisms for it in neuronal cells. Impact on host methylome and miRNAs can have wide spread alterations in gene expression, which might possibly help in understanding how haloperidol may impact treatment response or induce side effects.

Methods

SK-N-SH, a neuroblasoma cell line was treated with haloperidol at 10μm concentration for 24 hours and global DNA methylation was evaluated. Methylation at global level is maintained by methylation maintenance machinery and certain miRNAs. Therefore, the expression of methylation maintenance genes and their putative miRNA expression profiles were assessed. These global methylation alterations could result in gene expression changes. Therefore genes expressions for neurotransmitter receptors, regulators, ion channels and transporters were determined. Subsequently, we were also keen to identify a strong candidate miRNA based on biological and in-silico approach which can reflect on the pharmacoepigenetic trait of haloperidol and can also target the altered neuroscience panel of genes used in the study.

Results

Haloperidol induced increase in global DNA methylation which was found to be associated with corresponding increase in expression of various epigenetic modifiers that include DNMT1, DNMT3A, DNMT3B and MBD2. The expression of miR-29b that is known to putatively regulate the global methylation by modulating the expression of epigenetic modifiers was observed to be down regulated by haloperidol. In addition to miR-29b, miR-22 was also found to be downregulated by haloperidol treatment. Both these miRNA are known to putatively target several genes associated with various epigenetic modifiers, pharmacogenes and neurotransmission. Interestingly some of these putative target genes involved in neurotransmission were observed to be upregulated while CHRM2 gene expression was down regulated.

Conclusions

Haloperidol can influence methylation traits thereby inducing a pharmacoepigenomic response, which seems to be regulated by DNMTs and their putative miRNA expression. Increased methylation seems to influence CHRM2 gene expression while microRNA could influence neurotransmission, pharmacogene expression and methylation events. Altered expression of various therapeutically relevant genes and miRNA expression, could account for their role in therapeutic response or side effects.

Possible biomarkers modulating haloperidol efficacy and/or tolerability

Haloperidol (HP) is widely used in the treatment of several forms of psychosis. Despite of its efficacy, HP use is a cause of concern for the elevated risk of adverse drug reactions. adverse drug reactions risk and HP efficacy greatly vary across subjects, indicating the involvement of several factors in HP mechanism of action. The use of biomarkers that could monitor or even predict HP treatment impact would be of extreme importance. We reviewed the elements that could potentially be used as peripheral biomarkers of HP effectiveness. Although a validated biomarker still does not exist, we underlined the several potential findings (e.g., about cytokines, HP metabolites and genotypic biomarkers) which could pave the way for future research on HP biomarkers.

NeuN+ neuronal nuclei in non-human primate prefrontal cortex and subcortical white matter after clozapine exposure

Increased neuronal densities in subcortical white matter have been reported for some cases with schizophrenia. The underlying cellular and molecular mechanisms remain unresolved. We exposed 26 young adult macaque monkeys for 6 months to either clozapine, haloperidol or placebo and measured by structural MRI frontal gray and white matter volumes before and after treatment, followed by observer-independent, flow-cytometry-based quantification of neuronal and non-neuronal nuclei and molecular fingerprinting of cell-type specific transcripts. After clozapine exposure, the proportion of nuclei expressing the neuronal marker NeuN increased by approximately 50% in subcortical white matter, in conjunction with a more subtle and non-significant increase in overlying gray matter. Numbers and proportions of nuclei expressing the oligodendrocyte lineage marker, OLIG2, and cell-type specific RNA expression patterns, were maintained after antipsychotic drug exposure. Frontal lobe gray and white matter volumes remained indistinguishable between antipsychotic-drug-exposed and control groups. Chronic clozapine exposure increases the proportion of NeuN+ nuclei in frontal subcortical white matter, without alterations in frontal lobe volumes or cell type-specific gene expression. Further exploration of neurochemical plasticity in non-human primate brain exposed to antipsychotic drugs is warranted.

Applicability of gene expression and systems biology to develop pharmacogenetic predictors; antipsychotic-induced extrapyramidal symptoms as an example

Pharmacogenetics has been driven by a candidate gene approach. The disadvantage of this approach is that is limited by our current understanding of the mechanisms by which drugs act. Gene expression could help to elucidate the molecular signatures of antipsychotic treatments searching for dysregulated molecular pathways and the relationships between gene products, especially protein-protein interactions. To embrace the complexity of drug response, machine learning methods could help to identify gene-gene interactions and develop pharmacogenetic predictors of drug response. The present review summarizes the applicability of the topics presented here (gene expression, network analysis and gene-gene interactions) in pharmacogenetics. In order to achieve this, we present an example of identifying genetic predictors of extrapyramidal symptoms induced by antipsychotic.

MicroRNAs associated with ischemia-reperfusion injury and cardioprotection by ischemic pre- and postconditioning: protectomiRs

We aimed to characterize early changes in microRNA expression in acute cardioprotection by ischemic pre- and postconditioning in rat hearts. Hearts isolated from male Wistar rats were subjected to 1) time-matched nonischemic perfusion, 2) ischemia-reperfusion (30 min of coronary occlusion and 120 min of reperfusion), 3) preconditioning (3 × 5 min of coronary occlusion) followed by ischemia-reperfusion, or 4) ischemia-reperfusion with postconditioning (6 × 10 s of global ischemia-reperfusion at the onset of reperfusion). Infarct size was significantly reduced by both interventions. Of 350 different microRNAs assessed by microarray analysis, 147-160 microRNAs showed detectable expression levels. Compared with microRNA alterations induced by ischemia-reperfusion versus time-matched nonischemic controls, five microRNAs were significantly affected by both pre- and postconditioning (microRNA-125b*, microRNA-139-3p, microRNA-320, microRNA-532-3p, and microRNA-188), four microRNAs were significantly affected by preconditioning (microRNA-487b, microRNA-139-5p, microRNA-192, and microRNA-212), and nine microRNAs were significantly affected by postconditioning (microRNA-1, microRNA let-7i, microRNA let-7e, microRNA let-7b, microRNA-181a, microRNA-208, microRNA-328, microRNA-335, and microRNA-503). Expression of randomly selected microRNAs was validated by quantitative real-time PCR. By a systematic comparison of the direction of microRNA expression changes in all groups, we identified microRNAs, specific mimics, or antagomiRs that may have pre- and postconditioning-like cardioprotective effects (protectomiRs). Transfection of selected protectomiRs (mimics of microRNA-139-5p, microRNA-125b*, microRNA let-7b, and inhibitor of microRNA-487b) into cardiac myocytes subjected to simulated ischemia-reperfusion showed a significant cytoprotective effect. This is the first demonstration that the ischemia-reperfusion-induced microRNA expression profile is significantly influenced by both pre- and postconditioning, which shows the involvement of microRNAs in cardioprotective signaling. Moreover, by analysis of microRNA expression patterns in cardioprotection by pre- and postconditioning, specific protectomiRs can be revealed as potential therapeutic tools for the treatment of ischemia-reperfusion injury.

Weight gain in risperidone therapy: investigation of peripheral hypothalamic neurohormone levels in psychotic patients

The use of antipsychotic drugs has started a new era in the treatment of psychotic disorders. Nevertheless, they cause complications in the long-term treatment, which is mainly weight gain. In this study, we investigated circulating levels of hypothalamic neuropeptides, which are related to appetite regulation, neuropeptide Y (NPY), α-melanocyte-stimulating hormone (α-MSH), cocaine- and amphetamine-regulated transcript (CART), and leptin, in first-attack psychotic patients who were treated with an atypical antipsychotic drug, risperidone, for 4 weeks. We used a case-control association design to compare the neuropeptides in the control group versus before and after treatment of the patient group. Samples were obtained from psychotic patients who were admitted to the Psychiatry Outpatient Clinics, Gulhane School of Medicine, Ankara, Turkey. When compared with the control group, NPY and α-MSH plasma levels of psychotic patients were severely reduced, and the CART levels were substantially increased when they were first diagnosed (before treatment). However, the patients' body mass index and circulating leptin levels were markedly high after the treatment. Circulating levels of those neurohormones were not significantly changed between before and after treatment of the patients. These data demonstrate that peripheral α-MSH and NPY, although reflecting only secretion from peripheral organs, nevertheless, may provide an insight into the patients sympathetic tone and also suggest change of their appetite regulation. α-Melanocyte-stimulating hormone, NPY, and CART plasma levels may be used as a predictor of weight gain in the early treatment of the patients along with the leptin levels.

MicroRNA-25-dependent up-regulation of NADPH oxidase 4 (NOX4) mediates hypercholesterolemia-induced oxidative/nitrative stress and subsequent dysfunction in the heart

Diet-induced hypercholesterolemia leads to oxidative/nitrative stress and subsequent myocardial dysfunction. However, the regulatory role of microRNAs in this phenomenon is unknown. We aimed to investigate, whether hypercholesterolemia-induced myocardial microRNA alterations play a role in the development of oxidative/nitrative stress and in subsequent cardiac dysfunction. Male Wistar rats were fed with 2% cholesterol/0.25% cholate-enriched or standard diet for 12weeks. Serum and tissue cholesterol levels were significantly elevated by cholesterol-enriched diet. Left ventricular end-diastolic pressure was significantly increased in cholesterol-fed rats both in vivo and in isolated perfused hearts, indicating diastolic dysfunction. Myocardial expression of microRNAs was affected by cholesterol-enriched diet as assessed by microarray analysis. MicroRNA-25 showed a significant down-regulation as detected by microarray analysis and QRT-PCR. In silico target prediction revealed NADPH oxidase 4 (NOX4) as a putative target of microRNA-25. NOX4 protein showed significant up-regulation in the hearts of cholesterol-fed rats, while NOX1 and NOX2 remained unaffected. Cholesterol-feeding significantly increased myocardial oxidative/nitrative stress as assessed by dihydroethidium staining, protein oxidation assay, and nitro-tyrosine ELISA, respectively. Direct binding of microRNA-25 mimic to the 3' UTR region of NOX4 was demonstrated using a luciferase reporter assay. Transfection of a microRNA-25 mimic into primary cardiomyocytes decreased superoxide production, while a microRNA-25 inhibitor resulted in an up-regulation of NOX4 protein and an increase in oxidative stress that was attenuated by the NADPH oxidase inhibitor diphenyleneiodonium. Here we demonstrated for the first time that hypercholesterolemia affects myocardial microRNA expression, and by down-regulating microRNA-25 increases NOX4 expression and consequently oxidative/nitrative stress in the heart. We conclude that hypercholesterolemia-induced microRNA alterations play an important role in the regulation of oxidative/nitrative stress and in consequent myocardial dysfunction.

Functional analysis of gene expression in risperidone treated cells provide new insights in molecular mechanism and new candidate genes for pharmacogenetic studies

Risperidone is a potent antagonist of both dopamine and serotonin receptors. However, little is known about the underlying molecular mechanism by which risperidone acts. Although a number of genetic variants have been observed to correlate with treatment response there are no definitive predictors of response. We performed a genome-wide gene expression analysis (Human Genome U219 Array Plate) of a human neuroblastoma cell line (SK-N-SH) exposed to risperidone to identify molecular mechanisms involved in the cellular response to risperidone and thus identify candidate genes for pharmacogenetic studies. Our results revealed that cellular risperidone treatment is associated with a range of gene expression changes, which are time (6-48h) and dose related (0.1-10μM). We found that functional clusters of these changes correspond to Gene Ontology categories related to neural cell development functions, and synaptic structure and functions. We also identified Canonical Pathways related to these functional categories: neurogenesis and axon guidance; synaptic vesicle; and neurotransmitter signaling (dopamine, serotonin and glutamate). Finally, we identified candidate genes for pharmacogenetic studies related to the main risperidone secondary effects: motor disorders, cardiovascular disorders and metabolic disorders. Our results suggest that risperidone treatment affects the neurogenesis and neurotransmission of neuroblastoma cells, which is in agreement with the "initiation and adaptation" model to explain the mechanism of action of psychotropic drugs.

A gene expression and systems pathway analysis of the effects of clozapine compared to haloperidol in the mouse brain implicates susceptibility genes for schizophrenia

Clozapine has markedly superior clinical properties compared to other antipsychotic drugs but the side effects of agranulocytosis, weight gain and diabetes limit its use. The reason why clozapine is more effective is not well understood. We studied messenger RNA (mRNA) gene expression in the mouse brain to identify pathways changed by clozapine compared to those changed by haloperidol so that we could identify which changes were specific to clozapine. Data interpretation was performed using an over-representation analysis (ORA) of gene ontology (GO), pathways and gene-by-gene differences. Clozapine significantly changed gene expression in pathways related to neuronal growth and differentiation to a greater extent than haloperidol; including the microtubule-associated protein kinase (MAPK) signalling and GO terms related to axonogenesis and neuroblast proliferation. Several genes implicated genetically or functionally in schizophrenia such as frizzled homolog 3 (FZD3), U2AF homology motif kinase 1 (UHMK1), pericentriolar material 1 (PCM1) and brain-derived neurotrophic factor (BDNF) were changed by clozapine but not by haloperidol. Furthermore, when compared to untreated controls clozapine specifically regulated transcripts related to the glutamate system, microtubule function, presynaptic proteins and pathways associated with synaptic transmission such as clathrin cage assembly. Compared to untreated controls haloperidol modulated expression of neurotoxic and apoptotic responses such as NF-kappa B and caspase pathways, whilst clozapine did not. Pathways involving lipid and carbohydrate metabolism and appetite regulation were also more affected by clozapine than by haloperidol.

Antipsychotic induced alteration of growth and proteome of rat neural stem cells

Neural stem cells (NSCs) play a crucial role in the development and maturation of the central nervous system and therefore have the potential to target by therapeutic agents for a wide variety of diseases including neurodegenerative and neuropsychiatric illnesses. It has been suggested that antipsychotic drugs have significant effects on NSC activities. However, the molecular mechanisms underlying antipsychotic-induced changes of NSC activities, particularly growth and protein expression, are largely unknown. NSCs were treated with either haloperidol (HD; 3 μM), risperidone (RS; 3 μM) or vehicle (DMSO) for 96 h. Protein expression profiles were studied through a proteomics approach. RS promoted and HD inhibited the growth of NSCs. Proteomics analysis revealed that 15 protein spots identified as 12 unique proteins in HD-, and 20 protein spots identified as 14 proteins in RS-treated groups, were differentially expressed relative to control. When these identified proteins were compared between the two drug-treated groups, 2 proteins overlapped leaving 10 HD-specific and 12 RS-specific proteins. Further comparison of the overlapped altered proteins of 96 h treatment with the neuroleptics-induced overlapped proteins at 24 h time interval (Kashem et al. [40] in Neurochem Int 55:558-565, 2009) suggested that overlapping altered proteins expression at 24 h was decreased (17 proteins i.e. 53 % of total expressed proteins) with the increase of time (96 h) (2 proteins; 8 % of total expressed proteins). This result indicated that at early stage both drugs showed common mode of action but the action was opposite to each other while administration was prolonged. The opposite morphological pattern of cellular growth at 96 h has been associated with dominant expression of oxidative stress and apoptosis cascades in HD, and activation of growth regulating metabolic pathways in RS treated cells. These results may explain RS induced repairing of neural damage caused by a wide variety of neural diseases including schizophrenia.

Cathepsin K deficiency in mice induces structural and metabolic changes in the central nervous system that are associated with learning and memory deficits

Background

Cathepsin K is a cysteine peptidase known for its importance in osteoclast-mediated bone resorption. Inhibitors of cathepsin K are in clinical trials for treatment of osteoporosis. However, side effects of first generation inhibitors included altered levels of related cathepsins in peripheral organs and in the central nervous system (CNS). Cathepsin K has been recently detected in brain parenchyma and it has been linked to neurobehavioral disorders such as schizophrenia. Thus, the study of the functions that cathepsin K fulfils in the brain becomes highly relevant.

Results

Cathepsin K messenger RNA was detectable in all brain regions of wild type (WT) mice. At the protein level, cathepsin K was detected by immunofluorescence microscopy in vesicles of neuronal and non-neuronal cells throughout the mouse brain. The hippocampus of WT mice exhibited the highest levels of cathepsin K activity in fluorogenic assays, while the cortex, striatum, and cerebellum revealed significantly lower enzymatic activities. At the molecular level, the proteolytic network of cysteine cathepsins was disrupted in the brain of cathepsin K-deficient (Ctsk^-/-) animals. Specifically, cathepsin B and L protein and activity levels were altered, whereas cathepsin D remained largely unaffected. Cystatin C, an endogenous inhibitor of cysteine cathepsins, was elevated in the striatum and hippocampus, pointing to regional differences in the tissue response to Ctsk ablation. Decreased levels of astrocytic glial fibrillary acidic protein, fewer and less ramified profiles of astrocyte processes, differentially altered levels of oligodendrocytic cyclic nucleotide phosphodiesterase, as well as alterations in the patterning of neuronal cell layers were observed in the hippocampus of Ctsk^-/- mice. A number of molecular and cellular changes were detected in other brain regions, including the cortex, striatum/mesencephalon, and cerebellum. Moreover, an overall induction of the dopaminergic system was found in Ctsk^-/- animals which exhibited reduced anxiety levels as well as short- and long-term memory impairments in behavioral assessments.

Conclusion

We conclude that deletion of the Ctsk gene can lead to deregulation of related proteases, resulting in a wide range of molecular and cellular changes in the CNS with severe consequences for tissue homeostasis. We propose that cathepsin K activity has an important impact on the development and maintenance of the CNS in mice.

Gene expression profiling in rodent models for schizophrenia

The complex neurodevelopmental disorder schizophrenia is thought to be induced by an interaction between predisposing genes and environmental stressors. In order to get a better insight into the aetiology of this complex disorder, animal models have been developed. In this review, we summarize mRNA expression profiling studies on neurodevelopmental, pharmacological and genetic animal models for schizophrenia. We discuss parallels and contradictions among these studies, and propose strategies for future research.

Changes in gene expression following cardiac pacing-induced delayed cardioprotection in the canine heart

The aim of the present study was to identify gene expression changes in the rapid cardiac pacing-induced delayed antiarrhythmic protection in the canine, using cDNA microarrays and quantitative real-time PCR (QRT -PCR) techniques. In all dogs under light pentobarbitone anaesthesia, a pacing electrode was introduced into the right ventricle, and then the animals were divided into three groups: (1) sham-operated and sham-paced group (SP, n = 3) (2) ischaemic control group (IC; n = 3); these were without cardiac pacing and subjected only to a 25 min occlusion of the left anterior descending coronary artery (LAD), and (3) paced group (PC, n = 3); these animals were paced at a rate of 220-240 beats min-1 24 h prior to ischaemia. With cDNA chip 23 genes were found with altered expression in response to rapid cardiac pacing and 10 genes in the IC group when compared to SP dogs. These genes encode transcription factors (MEF2); members of signaling pathways (TGFβ2, PDE4D9), hormone related proteins (e.g. vasopressin V1 and V2 receptors). RT-QPCR was used either to confirm the results of the microarray analysis and also to study 46 genes which are already known to have a role in the late phase of PC. By this method 17 genes were up-regulated and 6 genes down-regulated in the IC group; their expression ratios changed either to the opposite or showed no alteration after cardiac pacing. This study would add some new information about those transcriptional changes that are involved in the delayed phase of cardiac protection.

Antipsychotic-induced gene regulation in multiple brain regions

The molecular mechanism of action of antipsychotic drugs is not well understood. Their complex receptor affinity profiles indicate that their action could extend beyond dopamine receptor blockade. Single gene expression studies and high-throughput gene profiling have shown the induction of genes from several molecular classes and functional categories. Using a focused microarray approach, we investigated gene regulation in rat striatum, frontal cortex, and hippocampus after chronic administration of haloperidol or olanzapine. Regulated genes were validated by in situ hybridization, real-time PCR, and immunohistochemistry. Only limited overlap was observed in genes regulated by haloperidol and olanzapine. Both drugs elicited maximal gene regulation in the striatum and least in the hippocampus. Striatal gene induction by haloperidol was predominantly in neurotransmitter signaling, G-protein coupled receptors, and transcription factors. Olanzapine prominently induced retinoic acid and trophic factor signaling genes in the frontal cortex. The data also revealed the induction of several genes that could be targeted in future drug development efforts. The study uncovered the induction of several novel genes, including somatostatin receptors and metabotropic glutamate receptors. The results demonstrating the regulation of multiple receptors and transcription factors suggests that both typical and atypical antipsychotics could possess a complex molecular mechanism of action.

Effects of typical and atypical antipsychotic drugs on gene expression profiles in the liver of schizophrenia subjects

BACKGROUND

Although much progress has been made on antipsychotic drug development, precise mechanisms behind the action of typical and atypical antipsychotics are poorly understood.

METHODS

We performed genome-wide expression profiling to study effects of typical antipsychotics and atypical antipsychotics in the postmortem liver of schizophrenia patients using microarrays (Affymetrix U133 plus2.0). We classified the subjects into typical antipsychotics (n = 24) or atypical antipsychotics (n = 26) based on their medication history, and compared gene expression profiles with unaffected controls (n = 34). We further analyzed individual antipsychotic effects on gene expression by sub-classifying the subjects into four major antipsychotic groups including haloperidol, phenothiazines, olanzapine and risperidone.

RESULTS

Typical antipsychotics affected genes associated with nuclear protein, stress responses and phosphorylation, whereas atypical antipsychotics affected genes associated with golgi/endoplasmic reticulum and cytoplasm transport. Comparison between typical antipsychotics and atypical antipsychotics further identified genes associated with lipid metabolism and mitochondrial function. Analyses on individual antipsychotics revealed a set of genes (151 transcripts, FDR adjusted p < 0.05) that are differentially regulated by four antipsychotics, particularly by phenothiazines, in the liver of schizophrenia patients.

CONCLUSION

Typical antipsychotics and atypical antipsychotics affect different genes and biological function in the liver. Typical antipsychotic phenothiazines exert robust effects on gene expression in the liver that may lead to liver toxicity. The genes found in the current study may benefit antipsychotic drug development with better therapeutic and side effect profiles.

Some molecular effectors of antidepressant action of quetiapine revealed by DNA microarray in the frontal cortex of anhedonic rats

OBJECTIVES AND METHODS

We have previously demonstrated that quetiapine (QTP) had antidepressant-like action by using the chronic mild stress (CMS) paradigm, an animal model of human depression. The aim of this study was to investigate the molecular mechanism(s) of QTP antidepressant effect by coupling the CMS protocol with Affymetrix microarray technology to screen the entire rat genome for gene changes in the frontal cortex.

RESULTS

The genes regulated by the administration of CMS whose transcription was reversed by chronic QTP treatment (2 mg/kg/day) were 42 (23 upregulated and 19 downregulated). The transcripts that showed no significant altered expression levels in anhedonic rats but were regulated by the administration of QTP were 19 (nine upregulated and 10 downregulated). On the whole, the action of QTP prevented the stress-induced impairment of some processes involved in central nervous system development or having a crucial role for viability of neural cells and cell-cell communications, like regulation of signal transduction, inorganic cation transport, membrane organization, and neurite morphogenesis. For 11 genes (Ptgs2, Gad1, Plcb1, Camk2a, Homer1, Senp2, Junb, Nfib, Hes5, Capon, and Marcks), significant differential expressions were confirmed by real-time reverse-transcriptase polymerase chain reaction.

CONCLUSION

We have shown that chronic QTP treatment prevented anhedonia and reversed, at least in part, the changes of gene expression induced by CMS in the rat frontal cortex. We have also identified and confirmed by two different methods that 11 genes, representing molecular targets of QTP, are presumably the effectors of its clinical efficacy.

Effects of typical (haloperidol) and atypical (risperidone) antipsychotic agents on protein expression in rat neural stem cells

Neural stem cells (NSCs) play a crucial role in the development and maturation of the central nervous system. Recently studies suggest that antipsychotic drugs regulate the activities of NSCs. However, the molecular mechanisms underlying antipsychotic-induced changes of the activity of NSCs, particularly protein expression, are still unknown. We studied the growth and protein expression in haloperidol (HD) and risperidone (RS) treated rat NSCs. The treatment with RS (3microM) or HD (3microM) had no effect on morphology of NSCs after 24h, but significantly promotes or inhibits the differentiation of NSCs after a 96h of treatment. 2-DE based proteomics was performed at 24h, a stage before phenotypic expression of NSCs. Gel image analysis revealed that 30 protein spots in HD- and 60 spots in RS-treated groups were differentially regulated in their expression compared to control group (p<0.05; ANOVA). When these spots were compared between the two drug-treated groups, 23 spots overlapped leaving 7 HD-specific and 37 RS-specific spots. Of these 67 spots, 32 different proteins were identified. The majority of the differentially regulated proteins were classified into several functional groups, such as cytoskeletal, calcium regulating protein, metabolism, signal transduction and proteins related to oxidative stress. Our data shows that atypical RS expressed more proteins than typical HD, and these results might explain the molecular mechanisms underlying the different effects of both drugs on NSCs activities as described above. Identified proteins in this experiment may be useful in future studies of NSCs differentiation and/or understanding in molecular mechanisms of different neural diseases including schizophenia.

Repeated risperidone treatment increases the expression of NCAM and PSA-NCAM protein in the rat medial prefrontal cortex

The present study investigates whether the anti-schizophrenic drug risperidone may evoke changes in the expression of NCAM/PSA-NCAM proteins, an indispensable element in the remodeling of synaptic arrangements, in the medial prefrontal cortex (mPFC). Rats were treated with risperidone (0.2 mg/kg, i.p.) either once or repeatedly (once a day, for 21 days). The expression of NCAM and PSA-NCAM proteins was analyzed via western blot and immunohistochemistry at intervals of 3 h and 3, 6, and 9 days after the single or the last risperidone dose. Repeated (but not acute) administration of risperidone was found to increase the expression of NCAM-180, NCAM-140 and PSA-NCAM proteins at 3 or 6 days after treatment. PSA-NCAM immunoreactivity was found in cell bodies, perisomatic-like sites, and in the neuropil of the mPFC. Neither single nor repeated risperidone administration changed the number of PSA-NCAM neurons in the mPFC. In contrast, the repeated risperidone treatment increased the number of PSA-NCAM perisomatic-like sites and the length density of PSA-NCAM positive neuropil at 3 days after the last injection. The data obtained indicate that risperidone, given repeatedly, may promote the remodeling of the structure of presumably GABA-ergic interneurons and that it may evoke the rearrangement of the synaptic contact in the mPFC.

Coregulation of genes in the mouse brain following treatment with clozapine, haloperidol, or olanzapine implicates altered potassium channel subunit expression in the mechanism of antipsychotic drug action

BACKGROUND

Antipsychotic drugs are the most effective treatment for the psychotic symptoms of schizophrenia, yet their mechanism of action remains largely unknown.

OBJECTIVES

Earlier studies have shown gene expression changes in rodent brains after treatment with antipsychotic drugs. We aimed to further characterize these changes using whole-genome transcript profiling to explore coregulation of genes after multiple antipsychotic drug treatment studies.

METHODS

This study involved transcript profile analysis after 7-day treatment of inbred C57BL/6 mice with conventional (haloperidol) or atypical (clozapine or olanzapine) antipsychotic drugs. Microarray analysis was undertaken using whole-brain mRNA on Affymetrix 430v2 arrays, with quantitative reverse transcriptase-PCR used to confirm gene expression changes. Western blotting was also used to explore translation of gene dysregulation to protein changes and to explore anatomical specificity of such changes.

MAIN RESULTS

Thirteen genes showed verified regulation by multiple antipsychotic drugs - three genes significantly upregulated and 10 genes significantly downregulated by treatment. These genes encode proteins that function in various biological processes including neurogenesis, cell adhesion, and four genes are involved in voltage-gated ion channels: neural precursor cell developmentally downregulated gene 4 (Nedd4), Kv channel interacting protein 3 (KChip3), potassium voltage-gated channel, shaker-related subfamily, alpha1 (Kcna1) encoding Kv1.1 protein and beta1 (Kcnab1) encoding Kvbeta1 protein. The translation of these gene expression changes to protein dysregulation for Kv1.1, KCHIP3, and NEDD4 was confirmed by western blot, with regional protein analyses undertaken for Kv1.1 and KCHIP3.

CONCLUSION

These results suggest that transcriptional regulation of ion channels, crucial for neurotransmission, may play a role in mediating antipsychotic drug effects.

Chronic treatment with aripiprazole induces differential gene expression in the rat frontal cortex

Chronic treatment of antipsychotic drugs can modulate gene expression in the brain, which may underscore their clinical efficacy. Aripiprazole is the first approved antipsychotic drug of the class of dopamine D2 receptor partial agonist, which has been shown to have similar efficacy and favourable side-effects profile compared to other antipsychotic drugs. This study aimed to identify differential gene expression induced by chronic treatment of aripiprazole. We used microarray-based gene expression profiling technology, real-time quantitative PCR and Western blot analysis to identify differentially expressed genes in the frontal cortex of rats under 4 wk treatment of aripiprazole (10 mg/kg). We were able to detect ten up-regulated genes, including early growth response gene 1, 2, 4 (Egr1, Egr2, Egr4), chromobox homolog 7 (Cbx7), cannabinoid receptor (Cnr1), catechol-O-methyltransferase (Comt), protein phosphatase 2c, magnesium dependent (Ppm2c), tachykinin receptor 3 (Tacr3), Wiscott-Aldrich syndrome-like gene (Wasl) and DNA methyltransferase 3a (Dnmt3a). Our data indicate that chronic administration of aripiprazole can induce differential expression of genes involved in transcriptional regulation and chromatin remodelling and genes implicated in the pathogenesis of psychosis.

Inflammation-related genes up-regulated in schizophrenia brains

BACKGROUND

Multiple studies have shown that brain gene expression is disturbed in subjects suffering from schizophrenia. However, disentangling disease effects from alterations caused by medication is a challenging task. The main goal of this study is to find transcriptional alterations in schizophrenia that are independent of neuroleptic treatment.

METHODS

We compared the transcriptional profiles in brain autopsy samples from 55 control individuals with that from 55 schizophrenic subjects, subdivided according to the type of antipsychotic medication received.

RESULTS

Using global and high-resolution mRNA quantification techniques, we show that genes involved in immune response (GO:0006955) are up regulated in all groups of patients, including those not treated at the time of death. In particular, IFITM2, IFITM3, SERPINA3, and GBP1 showed increased mRNA levels in schizophrenia (p-values from qPCR < or = 0.01). These four genes were co-expressed in both schizophrenic subjects and controls. In-vitro experiments suggest that these genes are expressed in both oligodendrocyte and endothelial cells, where transcription is inducible by the inflammatory cytokines TNF-alpha, IFN-alpha and IFN-gamma.

CONCLUSION

Although the modified genes are not classical indicators of chronic or acute inflammation, our results indicate alterations of inflammation-related pathways in schizophrenia. In addition, the observation in oligodendrocyte cells suggests that alterations in inflammatory-related genes may have consequences for myelination. Our findings encourage future research to explore whether anti-inflammatory agents can be used in combination with traditional antipsychotics for a more efficient treatment of schizophrenia.

Pharmacogenetics and pharmacogenomics of schizophrenia: a review of last decade of research

The last decade of research into the pharmacogenetics of antipsychotics has seen the development of genetic tests to determine the patients' metabolic status and the first attempts at personalization of antipsychotic treatment. The most significant results are the association between drug metabolic polymorphisms, mainly in cytochrome P450 genes, with variations in drug metabolic rates and side effects. Patients with genetically determined CYP2D6 poor metabolizer (PMs) status may require lower doses of antipsychotic. Alternatively, CYP2D6 ultrarapid matabolizers (UMs) will need increased drug dosage to obtain therapeutic response. Additionally, polymorphisms in dopamine and serotonin receptor genes are repeatedly found associated with response phenotypes, probably reflecting the strong affinities that most antipsychotics display for these receptors. In particular, there is important evidence suggesting association between dopamine 2 receptor (D2) polymorphisms (Taq I and -141-C Ins/Del) and a dopamine 3 receptor (D3) polymorphism (Ser9Gly) with antipsychotic response and drug-induced tardive dyskinesia. Additionally, there is accumulating evidence indicating the influence of a 5-HT2C polymorphism (-759-T/C) in antipsychotic-induced weight gain. Application of this knowledge to clinical practice is slowly gathering pace, with pretreatment determination of individual's drug metabolic rates, via CYP genotyping, leading the field. Genetic determination of patients' metabolic status is expected to bring clinical benefits by helping to adjust therapeutic doses and reduce adverse reactions. Genetic tests for the pretreatment prediction of antipsychotic response, although still in its infancy, have obvious implications for the selection and improvement of antipsychotic treatment. These developments can be considered as successes, but the objectives of bringing pharmacogenetic and pharmacogenomic research in psychiatric clinical practice are far from being realized. Further development of genetic tests is required before the concept of tailored treatment can be applied to psychopharmatherapy. This review aims to summarize the key findings from the last decade of research in the field. Current knowledge on genetic prediction of drug metabolic status, general response and drug-induced side effects will be reviewed and future pharmacogenomic and epigenetic research will be discussed.

Olanzapine increases RGS7 protein expression via stimulation of the Janus tyrosine kinase-signal transducer and activator of transcription signaling cascade

Atypical antipsychotics such as olanzapine have high affinity for multiple monoamine neurotransmitter receptors and are the mainstay of pharmacological therapy for treatment of schizophrenia. In addition to blocking monoamine receptors, these drugs also affect intracellular signaling cascades. We now report that 24-h treatment with 300 nM olanzapine causes desensitization of serotonin (5-HT)(2A) receptors in A1A1v cells, a rat cortical cell line, as indicated by a reduction in inositol phosphate accumulation following stimulation with a 5-HT(2A/2C) receptor agonist (-)-1-(2,5-dimethoxy-4-lodophenyl)-2-aminopropane HCl. Olanzapine treatment for 24 h increased the levels of 5-HT(2A) receptors in both cytosol (234 +/- 34% of control level) and membrane fractions (206 +/- 14% of control levels) and RGS7 proteins in both cytosol (193 +/- 32% of control levels) and membrane fractions (160 +/- 18% of control levels) as measured on Western blots. Increased phosphorylation of Janus tyrosine kinase (JAK) 2 and increased phosphorylation and nuclear translocation of signal transducer and activator of transcription (STAT) 3 with 24-h olanzapine treatment demonstrate activation of the JAK-STAT signaling cascade. Pretreatment with a JAK inhibitor, AG490 [alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide], prevented the olanzapine-induced increase in membrane RGS7 protein levels; AG490 alone had no effect on RGS7 protein levels. We verified that treatment with AG490 reduced phosphorylation of JAK2 and inhibited the nuclear localization of phospho-STAT3. Interestingly, treatment with the JAK inhibitor had no effect on 5-HT(2A) receptor protein levels. These data suggest that olanzapine-induced activation of the JAK-STAT signaling cascade causes increased expression of RGS7 protein, which in turn could mediate desensitization of 5-HT(2A) receptor signaling caused by olanzapine because RGS7 binds to Galpha(q) protein and accelerates GTP hydrolysis.

Molecular profiling of antipsychotic drug function: convergent mechanisms in the pathology and treatment of psychiatric disorders

Despite great progress in antipsychotic drug research, the molecular mechanisms by which these drugs work have remained elusive. High-throughput gene profiling methods have advanced this field by allowing the simultaneous investigation of hundreds to thousands of genes. However, different methodologies, choice of brain region, and drugs studied have made comparisons across different studies difficult. Because of the complexity of gene expression changes caused by drugs, teasing out the most relevant expression differences is a challenging task. One approach is to focus on gene expression changes that converge on the same systems that were previously deemed important to the pathology of psychiatric disorders. From the microarray studies performed on human postmortem brain samples from schizophrenics, the systems most implicated to be dysfunctional are synaptic machinery, oligodendrocyte/myelin function, and mitochondrial/ubiquitin metabolism. Drugs may act directly or indirectly to compensate for underlying pathological deficits in schizophrenia or via other mechanisms that converge on these pathways. Side effects, consisting of motor and metabolic dysfunction (which occur with typical and atypical drugs, respectively), also may be mediated by gene expression changes that have been reported in these studies. This article surveys both the convergent antipsychotic mechanisms and the genes that may be responsible for other effects elicited by antipsychotic drugs.

Effects of chronic risperidone treatment on the striatal protein profiles in rats

Extrapyramidal symptoms (EPS) commonly occur as side effects of antipsychotic drugs (APDs) and are most likely to arise when the occupancy of dopamine D(2) receptors in the striatum by these drugs exceeds 80%. We aimed to characterize changes in the protein expression profile in the striatum of rats after chronic (4 week) supra-therapeutic (EPS-inducing) treatment with risperidone (RIS), an atypical antipsychotic drug. Administration of RIS (2.1 mg/kg/day, via subcutaneous osmotic minipumps) induced significant vacuous chewing movements and catalepsy in male Sprague-Dawley rats over a 28-day treatment period compared with a vehicle (VEH) control group (n=12) (Karl et al., unpublished observation). Using two-dimensional gel electrophoresis (2DE), total protein extracts from the rat brain striatum were separated and protein expression was analyzed by Phoretix 2D Expression and Image Beta V4.02 software followed by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). 2DE gels resolved up to 450 protein spots, presumably different proteins and/or their isoforms. There were 30 protein spots showing statistically significant different densities between the RIS- and VEH-treated groups. All 30 proteins were successfully identified by MALDI-TOF MS, 28 of these were divided into groups based on their known functions. These included metabolic, signaling, transport, protein metabolism, chaperone, DNA binding and cell cycle categories. We conclude that chronic risperidone treatment accompanied by an EPS-like behavioral phenotype results in alterations in the striatal protein profile possibly subsequent to blockade of dopaminergic systems. These results suggest that possible mechanisms involved in APD-induced EPS include metabolic dysfunction and oxidative stress.

Transcriptional response to the neuroleptic-like compound Ampullosporin A in the rat ketamine model

Psychotic disorders affecting up to 1% of the human population represent pathological changes to the metabolic homeostasis of the brain. Increasing evidence in the literature suggests complex biochemical and/or transcriptional alterations accompanying schizophrenia-like phenomena. Sub-chronic treatment with sub-anaesthetic doses of ketamine induces schizophrenia-related psychotic alterations that can be used as an animal model in the study of this disorder. Ampullosporin A belongs to a specific group of pore-forming fungal peptides, peptaibols. We focused on the analysis of molecular events occurring in the brain of ketamine-pre-treated rats after administration of Ampullosporin A with neuroleptic-like activity. The complex experimental approach allowed us to correlate the use of low molecular weight substances with a transcriptome fingerprint in the prefrontal cortex. We found 63 genes to be up-regulated and 22 genes suppressed, with transthyretin, syndecan-1 and NeuroD1 showing the highest degree of up-regulation. Our results suggest the possibility that Ampullosporin A belongs to the group of neuroleptic-like compounds, inducing massive changes in neurotransmitter receptor composition, calcium signalling cascades and second messenger systems, and leading to the plastic reorganization of brain tissue, metabolic pathways and synapses.

Impact of venlafaxine on gene expression profile in lymphocytes of the elderly with major depression--evolution of antidepressants and the role of the "neuro-immune" system

Antidepressive drugs offer considerable symptomatic relief in mood disorders and, although commonly discovered by screening with single biological targets, most interact with multiple receptors and signaling pathways. Antidepressants require a treatment regimen of several weeks before clinical efficacy is achieved in patient populations. While the biochemical mechanisms underlying the delayed temporal profile remain unclear, molecular adaptations over time are likely involved. The selective serotonin and noradrenaline reuptake inhibitor, venlafaxine, offers a dual antidepressive action. Its pharmacological behavior, however, is unknown at the genetic level, and it is difficult to monitor in human brain samples. Because the hypothalamic-pituitary-adrenal axis is often severely disrupted in mood disorders, lymphocytes may serve as models of neuropsychiatric conditions. As such, we examined the role of venlafaxine on the gene expression profile of human lymphocytes. DNA microarray was used to measure the expression patterns of multiple genes in human lymphocytes from depressed patients treated with this mood stabilizer. In this self-controlled study, RNAs of control and treated samples were purified, converted into cDNA and labeled with either Cy3 or Cy5, mixed and hybridized to DNA microarrays containing human oligonucleotides corresponding to more than 8,000 genes. Genes that were differentially regulated in response to treatment were selected for follow up on the basis on novelty, gene identity, and level of over-expression/repression, and selected transcripts were profiled by real-time PCR (data have been normalized to beta-actin). Using software analysis of the microarray data, a number of transcripts were differentially expressed between control and treated samples, of which only 57 were found to significantly vary with the "P" value of 0.05 or lower as a result of exposure to venlafaxine. Of these, 31 genes were more highly expressed and 26 transcripts were found to be significantly less abundant. Most selected genes were verified with QRT-PCR to alter. As such, independent verification using QRT-PCR demonstrated the reliability of the method. Genes implicated in ionic homeostasis were differentially expressed, as were genes associated with cell survival, neural plasticity, signal transduction, and metabolism. Understanding how gene expression is altered over a clinically relevant time course of administration of venlafaxine may provide insight into the development of antidepressant efficacy as well as the underlying pathology of mood disorders. These changes in lymphocytes are thought to occur in the brain, and a "neuro-immune system" is proposed by this study.

Antipsychotic pathway genes with expression altered in opposite direction by antipsychotics and amphetamine

To develop a new strategy for identifying possible psychotic- or antipsychotic-related pathway genes, rats were treated with clinical doses of haloperidol and clozapine for 4 days, and the altered expression of genes was compared with the genes altered in expression after amphetamine sensitization. The objective was to identify genes with expression altered in the same direction by haloperidol and clozapine but in the opposite direction in the amphetamine-sensitized rat striatum. These criteria were met by 21 genes, consisting of 15 genes upregulated by amphetamine, and 6 genes downregulated by amphetamine. Of the 21 genes, 15 are not presently identified, and only 3 genes (cathepsin K, GRK6, and a gene with accession number AI177589) are located in chromosome regions known to be associated with schizophrenia.