Project description:Major depression is a multidimensional disorder highly prevalent in modern society. Although several classes of antidepressants (ADs) are currently available to treat depression, the effectiveness of treatment is still limited, as many patients do not show full remission; thus, there is a need to find better patients’ directed therapeutic strategies. Neuroplastic changes in several brain regions, namely in the hippocampal dentate gyrus (DG), are amongst the best correlates of depression and of ADs actions. In this study the targets and molecular mediators of chronic stress and of four ADs from different pharmacological classes (fluoxetine, imipramine, tianeptine and agomelatine) were investigated in the DG. Using the unpredictable chronic mild stress (uCMS) animal model of depression, the molecular commonalities and specificities of the ADs were determined. All ADs, except agomelatine, could reverse the behavioral deficits produced by uCMS, and the neuroplastic changes in the DG; agomelatine reversed only the anhedonic profile in the sucrose consumption test. Chronic stress induced mild but relevant molecular changes that were mostly reversed by fluoxetine, imipramine and tianeptine. Fluoxetine reduced pro-inflammatory response and increased cell metabolism pathways. Its actions were mostly dependent on molecular changes occurring in neurons. Similarities were found between imipramine and tianeptine molecular actions and targets, as both activated pathways related to cellular protection. Moreover, no particular neural cell type enrichment was found with both treatments. Agomelatine presented a very dissimilar molecular pattern impacting greatly on Rho-GTPases-related pathways in oligodendrocytes and neurons. The recognition of these molecular alterations contributes to the understanding of the processes implicated in the onset and treatment of depression and may pave the way for more effective therapeutic interventions. We compared gene expresssion in the dentate gyros of rats which were either untreated, exposed to unpredictable chronic mild stress, or exposed to the same stress and treated with either fluoxetine, imipramine, tianeptine, or agomelatine
Project description:Major depression is a multidimensional disorder highly prevalent in modern society. Although several classes of antidepressants (ADs) are currently available to treat depression, the effectiveness of treatment is still limited, as many patients do not show full remission; thus, there is a need to find better patients’ directed therapeutic strategies. Neuroplastic changes in several brain regions, namely in the hippocampal dentate gyrus (DG), are amongst the best correlates of depression and of ADs actions. In this study the targets and molecular mediators of chronic stress and of four ADs from different pharmacological classes (fluoxetine, imipramine, tianeptine and agomelatine) were investigated in the DG. Using the unpredictable chronic mild stress (uCMS) animal model of depression, the molecular commonalities and specificities of the ADs were determined. All ADs, except agomelatine, could reverse the behavioral deficits produced by uCMS, and the neuroplastic changes in the DG; agomelatine reversed only the anhedonic profile in the sucrose consumption test. Chronic stress induced mild but relevant molecular changes that were mostly reversed by fluoxetine, imipramine and tianeptine. Fluoxetine reduced pro-inflammatory response and increased cell metabolism pathways. Its actions were mostly dependent on molecular changes occurring in neurons. Similarities were found between imipramine and tianeptine molecular actions and targets, as both activated pathways related to cellular protection. Moreover, no particular neural cell type enrichment was found with both treatments. Agomelatine presented a very dissimilar molecular pattern impacting greatly on Rho-GTPases-related pathways in oligodendrocytes and neurons. The recognition of these molecular alterations contributes to the understanding of the processes implicated in the onset and treatment of depression and may pave the way for more effective therapeutic interventions.
Project description:The glucocorticoid receptor overexpression in early life is sufficient to alter gene expression patterns for the rest of the animal's life. Hippocampal dentate gyrus (DG) are more responsive than the nucleus accumbens (NAcc) following the glucocorticoid receptor overexpression in the forebrain. Laser capture microdissection was performed. Microdissected areas from the dentate gyrus or nucleus accumbens were collected from serial sections for each animal.
Project description:Hippocampal sclerosis (HS) is the most common neuropathological finding of medically intractable cases of mesial temporal lobe epilepsy (MTLE), the most common form of partial epilepsy. Within the dentate gyrus, HS may be associated with granule cell dispersion and aberrant mossy fiber sprouting, and these pathological changes are accompanied by a range of molecular changes. In this study, we analyzed the gene expression profiles of dentate granule cells of MTLE patients with and without HS to show that next-generation sequencing methods can produce interpretable genomic data from RNA collected from small homogenous cell populations and to shed light on the transcriptional changes associated with HS. 12 samples of dentate granule cells from patients with mesial tempora lobe epilepsy, 5 with hippocampal sclerosis and 7 without hippocampal sclerosis. 10 samples had replicates.