Project description:We evaluate the effects of chronic administration of antipsychotic haloperidol versus placebo in male, 8-week old, C57BL/6J mice. We used microarray to study gene expression changes after haloperidol treatment in mouse brain and liver
Project description:Background. Schizophrenia is an idiopathic psychiatric disorder with a high degree of polygenicity. Evidence from genetics, single-cell, and pharmacological studies suggest an important overlap between genes involved in the etiology of schizophrenia and the cellular mechanisms of action of antipsychotics in medium spiny neurons (MSNs). Methods. We applied single-cell RNA-sequencing to striatal samples from C57BL/6J mice chronically exposed to a typical antipsychotic (haloperidol), an atypical antipsychotic (olanzapine), or placebo. We implemented careful statistical analyses to identify differentially expressed genes in two cell populations identified from the single-cell RNA-sequencing (MSNs and microglia) and applied multiple analysis pipelines to contextualize these findings. Results. Differential expression analysis showed that there was a larger share of differentially expressed genes (DEGs) in MSNs from mice treated with olanzapine vs. haloperidol. DEGs were enriched in broad loci implicated by genetic studies of schizophrenia, and we highlighted nine genes with convergent evidence. Pathway analyses highlighted alternative splicing, mitochondrial function, and neuron and synapse development as particularly engaged by antipsychotics. In microglia, we identified pathways involved in microglial activation and inflammation as part of the antipsychotic response. Conclusions. Our goal was to evaluate connections between schizophrenia genetic findings and cellular gene expression changes following antipsychotic exposure. We found that differential gene expression in MSNs from mice chronically treated with olanzapine converges on similar pathways and gene sets.
Project description:Schizophrenia is a chronic mental illness that is among the world’s top twenty causes of years lost to disability according to the global burden of disease 2019 (10.1016/S0140-6736(20)30925-9). Positive symptoms, including hallucinations and delusions in schizophrenia, often improved with conventional antipsychotic medication, which exerts its therapeutic effects mainly by antagonizing the dopamine D2 receptors. Haloperidol was one of the first antipsychotics to be approved by the FDA, and it is since then widely used for the treatment of psychotic disorders including schizophrenia. Despite its high affinity for dopamine D2 receptors, it has been shown that haloperidol interacts with other receptors, such as dopamine D3 and D4 receptors, α-adrenergic receptor 1 and to some extent 5HT2A. Dopaminergic dysfunction is known for decades to be involved in the pathophysiology of schizophrenia, but only recently has the striatum been implicated in such devasting disorder. The dorsal striatum is a brain region involved in motor, cognitive and motivational functions, highly impacted by antipsychotic drugs. Particularly, it is well-recognized that chronic haloperidol administration has a tremendous impact on striatal synaptic plasticity, by changing the volume of dorsal striatum, the number of striatal neurons and the synaptic morphology, both in humans and rodents. Despite the overwhelming evidence correlating chronic haloperidol administration with striatum alterations, so far, the exact striatal synaptic mechanism by which haloperidol exerts its beneficial effects remains unclear. Although dopamine D2 receptor blockade can be achieved within hours after haloperidol administration, the onset of action is delayed by weeks. Thus, it is crucial to better understand the neuronal mechanism behind the delayed clinical effects of haloperidol to improve the treatment outcome. Using proteomic analysis and whole-cell patch-clamp recordings (Figure 1), we demonstrate for the first time a possible mechanism by which haloperidol may be contributing to its beneficial long-term therapeutic effect. Specifically, we demonstrate that modulation of D2-MSNs by chronic haloperidol administration leads to a slow remodeling of D1-neurons that may be responsible for its positive therapeutic effects.
Project description:Atypical antipsychotic Clozapine has a superior antipsychotic and antimanic effects compared to other antisphicotics. Its widespread use was limited by the side effects of agranulocytosis, cardiomyopathy and metabolic anomalies such as weight gain, and diabetes. Very little is known about mechanisms by which Clozapine works. The aim of this experiment is to compare the chronic gene expression profile of the atypical antipsychotic Clozapine to the typical antipsychotic drug Haloperidol using gene expression Microarray in order to understand the intercellular mechanism behind the therapeutic and the toxic effects of Clozapine. Experiment Overall Design: The study was designed to compare the chronic therapeutic and toxic expression profile of Clozapine to Haloperidol in the mouse brain. All experiments were performed in male C57BL mice at four weeks of age (Biological services, University Collage London). Several theoretical and practical considerations influenced the final experimental design. To avoid the effect of injections on genes expression and to simulate the clinical scenario in human, both drugs were applied to the animals drinking water using the maximum human therapeutic dose (i.e. 1.6mg/kg/day for Haloperidol and 12mg/kg/day for Clozapine). Thirty animals were divided equally between three treatment groups and received either Haloperidol (10 animals), Clozapine (10 animals) or no treatment (10 animals) for 12 weeks. After twelve weeks, the total RNA from the right forebrains were extracted and hybridized to the Affymetrix MOE430A array. In all the Microarray experiments we have avoided pooling and each RNA sample was an independent biological replicate. The total numbers of used arrays were 30 Affymetrix MOE430A arrays.
Project description:Atypical antipsychotic Clozapine has a superior antipsychotic and antimanic effects compared to other antisphicotics. Its widespread use was limited by the side effects of agranulocytosis, cardiomyopathy and metabolic anomalies such as weight gain, and diabetes. Very little is known about mechanisms by which Clozapine works. The aim of this experiment is to compare the chronic gene expression profile (i.e four weeks) of the atypical antipsychotic Clozapine to the typical antipsychotic drug Haloperidol using gene expression Microarray in order to understand the intercellular mechanism behind the therapeutic and the toxic effects of Clozapine. Experiment Overall Design: The study was designed to compare the chronic therapeutic and toxic expression profile of Clozapine to Haloperidol in the mouse brain. All experiments were performed in male C57BL mice at four weeks of age (Biological services, University Collage London). Several theoretical and practical considerations influenced the final experimental design. To avoid the effect of injections on genesâ expression and to simulate the clinical scenario in human, both drugs were applied to the animalsâ drinking water using the maximum human therapeutic dose (i.e.1.6mg/kg/day for Haloperidol and 12mg/kg/day for Clozapine).Thirty animals were divided equally between three treatment groups and received either Haloperidol (10 animals), Clozapine (10 animals) or no treatment (10 animals) for 4 weeks. After four weeks,the plasma drug level for both drugs was assesed by Tandem mass Spectrometry LC- MS/MS. The total RNA from the right forebrains of nine selected animals (three from each treatment group) were extracted and hybridized to the Affymetrix U74Av2. In all the Microarray experiments we have avoided pooling and each RNA sample was an independent biological replicate. The total numbers of used arrays were 9 Affymetrix U74Av2.
Project description:Atypical antipsychotic Clozapine has a superior antipsychotic and antimanic effects compared to other antisphicotics. Its widespread use was limited by the side effects of agranulocytosis, cardiomyopathy and metabolic anomalies such as weight gain, and diabetes. Very little is known about mechanisms by which Clozapine works. The aim of this experiment is to compare the chronic gene expression profile (i.e four weeks) of the atypical antipsychotic Clozapine to the typical antipsychotic drug Haloperidol using gene expression Microarray in order to understand the intercellular mechanism behind the therapeutic and the toxic effects of Clozapine. Keywords: drug response
Project description:Atypical antipsychotic Clozapine has a superior antipsychotic and antimanic effects compared to other antisphicotics. Its widespread use was limited by the side effects of agranulocytosis, cardiomyopathy and metabolic anomalies such as weight gain, and diabetes. Very little is known about mechanisms by which Clozapine works. The aim of this experiment is to compare the chronic gene expression profile of the atypical antipsychotic Clozapine to the typical antipsychotic drug Haloperidol using gene expression Microarray in order to understand the intercellular mechanism behind the therapeutic and the toxic effects of Clozapine. Keywords: drug response
Project description:SD rats were dosed with gold standard antipsychotic therapies, haloperidol or risperidone, at doses aimed at achieving therapeutically relevant drug exposures. Tissues were collected after 21 days of delivery to examine the impact of this treatment on gene expression in frontal cortex, hippocampus and striatum.