Effect of chronic fluoxetine treatment on hippocampal gene expression
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE6476 | GEO | 2007/07/04
SECONDARY ACCESSION(S): PRJNA98715
REPOSITORIES: GEO
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Project description:Both the mechanism of action and the factors determining the behavioral response to antidepressants are unknown. It has been shown that antidepressant treatment promotes the proliferation and survival of hippocampal neurons via enhanced serotonergic signaling, but it is still unclear whether hippocampal neurogenesis is responsible for the behavioral response to antidepressants. Furthermore, a large subpopulation of patients fails to respond to antidepressant treatment due to presumed underlying genetic factors. In the present study, we have used the phenotypic and genotypic variability of inbred mouse strains to show that there is a genetic component to both the behavioral and neurogenic effects of chronic fluoxetine treatment, and that this antidepressant induces an increase in hippocampal cell proliferation only in the strains that also show a positive behavioral response to treatment. The behavioral and neurogenic responses are associated with an upregulation of genes known to promote neuronal proliferation and survival. These results suggest that inherent genetic predisposition to increased serotonin-induced neurogenesis is a determinant of antidepressant efficacy. Experiment Overall Design: Male DBA/2J, age 3-5 weeks, were obtained from The Jackson Laboratory (Bar Harbor, ME) and maintained on a 12:12 light:dark cycle with lights on at 0700 hours. Following at least one week of acclimation, mice were provided with either untreated or fluoxetine-treated drinking water, available ad libitum. Fluoxetine-HCl was obtained from Spectrum Chemicals (Gardena, CA). Differences in daily water consumption were previously determined by measuring water intake for three weeks from at least 12 mice (6.4 mL (+/- .58 mL) per day). We also determined the average weight at 10 weeks of age (25.5 g +/- 1.4 g), and used this information to dilute fluoxetine in the water in order to provide a daily dosage of 0 or 18 mg/kg/mouse. Experiment Overall Design: Mice were 8-12 weeks of age at the time of behavioral testing, which was performed during the light phase between 1300h and 1600h. Behavioral despair was measured using a mouse Tail Suspension apparatus from Med Associates (Georgia, VT). Experiment Overall Design: Individual bilateral hippocampii from 21-day-treatment 0 and 18 mg/kg/day DBA/2J mice were homogenized in 500 µl TRIzol using a QIAgen Tissuelyser (15 minutes at 30 Hz, QIAgen, Chatsworth, CA). RNA was extracted by phenol-chloroform phase separation and further processed using the RNAeasy miniprep kit (QIAgen). For each treatment group of 12 animals, separate RNA pools were made using hippocampal RNA from 6 mice per pool. These biological replicates were processed separately through the entirety of the microarray procedure. Five µg of total RNA from each pool was used as a template to synthesize complementary DNA (cDNA) and biotinylated cRNA (Enzo kit, Affymetrix, Santa Clara, CA) using standard Affymetrix protocols. cRNA was hybridized to Affymetrix GeneChip Mouse Genome 430 2.0 Array. Data were analyzed using ArrayAssist software (Stratagene, La Jolla, CA) and normalized with the GCRMA algorithm. A probeset had to obtain a minimal intensity value 100 to be considered as detecting expression above background. Therefore, any probeset that failed to meet this cutoff was removed from the analysis. Ratios of intensity differences were generated and genes showing at least a two-fold difference between experimental conditions were identified for further analysis.
2008-06-14 | E-GEOD-6476 | biostudies-arrayexpress
Project description:Adult Neurogenesis and Gene Expression Changes in 5-HT7 Receptor Knockout Mice: In the adult, the formation of new nerve cells in the CNS is restricted to the subependymal layer and to the subgranular zone of the hippocampus (Duman et al., 2001). Clinically adult neurogenesis has received most attention for its possible role in major depression. Depressed patients have reduced hippocampal neurogenesis (Kasper & McEwen, 2008) and hippocampal volume (Colla et al., 2007). It has also been shown that chronic, but not acute, treatment with currently widely used antidepressants, most notably fluoxetine, results in increased hippocampal neurogenesis (Malberg et al., 2000; Miller et al., 2007). Pharmacologically antidepressants act by elevating the amount of synaptic serotonin (5-HT) and they do that within minutes of administration, but the clinical effect is often delayed, sometimes for weeks (Miller et al., 2007). This delay is believed to involve changes in plasticity and neurogenesis. With currently available treatment options for depression 20% or more of patients do not respond to the therapy. Thus, there is a need for an increased understanding of the mechanism behind plasticity and neurogenesis, and for the development of improved therapies for depression. We have in an ongoing project with the aim to functionally characterize the 5-HT7 receptor, one of the most recently discovered receptor subtypes for 5-HT (Lovenberg et al., 1993). Interestingly, we have found that this receptor might be a new target for the treatment of depression. Inactivation or pharmacological blockade of this receptor induces an antidepressant-like profile in several preclinical models of depression (Hedlund et al., 2005; Guscott et al., 2005; Wesolowska et al., 2006a, 2006b) and in sleep patterns (Thomas et al., 2003; Hedlund et al., 2005). Of special interest is also the finding that inhibition of the 5-HT7 receptor potentiates the effect of antidepressants in behavioral models of depression (Wesolowska et al., 2007; Bonaventure et al., 2007). We have recently determined that mice lacking lacking the 5-HT7 receptor show a 25% decrease in the number of proliferating cells in the subgranular zone of the hippocampus compared to wildtype mice. The mice were treated with BrdU, a thymidine analog that is incorporated into the DNA of cells undergoing mitosis. BrdU was then detected immunohistochemically. Both wildtype and knockout mice responded to fluoxetine treatment with an increase in the number of dividing cells. The reduction in the number of dividing cells in the 5-HT7 receptor knockout mice seemingly contradicts the antidepressant-like profile previously observed in these mice, but might on the other hand help to explain previously observed impairments in hippocampus-dependent learning seen in the knockout mice (Roberts et al., 2004) and after pharmacological blockade (Meneses, 2004). The observation that 5-HT7 receptors influence neurogenesis constitutes an entirely new regulatory mechanism for this physiologically and pathophysiologically important process. In order to further understand hippocampal neurogenesis and how it is influenced by 5-HT in general and 5-HT7 receptors in particular we propose to perform a microarray study using the glycogene array designed by the Consortium for Functional Glycomics using total RNA from the hippocampus. A comparison will be made between young adult male mice lacking the 5-HT7 receptor and wildtype sibling controls. Such a study should yield new valuable insights into the pathways regulating neurogenesis. The glycogene array is of particular interest as it includes several genes that have been shown to be either directly or indirectly involved in adult neurogenesis and to be regulated by 5-HT and antidepressants. Of particular interest are cell adhesion molecules which are glycoproteins. One such molecule is NCAM, a marker for immature neurons undergoing remodeling and plasticity (Nakagawa et al., 2002), which is upregulated by fluoxetine treatment (Varea et al., 2006). In contrast, NCAM is downregulated following 5-HT depletion (Brezun & Daszuta, 1999). Chronic fluoxetine treatment has also been shown to upregulate neuropeptide Y, Galectin I, Activin A receptor and Inhibin beta-A, all included in the glycogene array (Miller et al., 2007). Another relevant gene on the glycogene chip is ST8SiaIV (Nakagawa et al., 2002). Experimental Design: The hippocampus will be dissected and total RNA will be extracted according to recommended protocols for array studies. RNA from a sufficient number (2-3 animals) of male 5-HT7 receptor knockout mice will be pooled for each of the three replicates. Control samples will be similarly generated from wildtype siblings. The 5-HT7 receptor mice are on a genetically homogeneous background (backcrossed for 16 generation on a C57BL6/J background) so inter-animal variability should be negligible. The RNA will be analyzed on the glycogene array. 3 KO replicates + 3 WT replicates per glycogene array = 6 arrays
2011-09-05 | E-GEOD-31924 | biostudies-arrayexpress
Project description:We performed high-throughput profiling of gene expression in mouse prefrontal cortex in response to antidepressant treatment. BALB/c mice were treated with sertraline, duloxetine, or water for three weeks. Then we performed forced swim test to check their antidepressant-like behavior. We divided these animals to responder and non-responder based on their behavior in the forced swim test. We then conducted the transcriptomics analysis and found specific and distinct genes in responder and non-responder mice. Our study provided deep insights into the understanding of the molecular mechanisms underlying the behavioral response to antidepressants.
2022-01-17 | GSE168172 | GEO
Project description:Adult Neurogenesis and Gene Expression Changes in 5-HT7 Receptor Knockout Mice: In the adult, the formation of new nerve cells in the CNS is restricted to the subependymal layer and to the subgranular zone of the hippocampus (Duman et al., 2001). Clinically adult neurogenesis has received most attention for its possible role in major depression. Depressed patients have reduced hippocampal neurogenesis (Kasper & McEwen, 2008) and hippocampal volume (Colla et al., 2007). It has also been shown that chronic, but not acute, treatment with currently widely used antidepressants, most notably fluoxetine, results in increased hippocampal neurogenesis (Malberg et al., 2000; Miller et al., 2007). Pharmacologically antidepressants act by elevating the amount of synaptic serotonin (5-HT) and they do that within minutes of administration, but the clinical effect is often delayed, sometimes for weeks (Miller et al., 2007). This delay is believed to involve changes in plasticity and neurogenesis. With currently available treatment options for depression 20% or more of patients do not respond to the therapy. Thus, there is a need for an increased understanding of the mechanism behind plasticity and neurogenesis, and for the development of improved therapies for depression.
2011-09-06 | GSE31924 | GEO
Project description:Adult hippocampal neurogenesis is important for certain forms of cognition and failing neurogenesis has been implicated in neuropsychiatric diseases. The neurogenic capacity of hippocampal neural stem/progenitor cells (NSPCs) depends on a balance between quiescent and proliferative states. However, how this balance is regulated remains poorly understood. Here we show that the rate of fatty acid oxidation (FAO) defines quiescence vs. proliferation in NSPCs. Quiescent NSPCs show high levels of carnitine palmitoyltransferase 1a (Cpt1a)-dependent FAO, which is downregulated in proliferating NSPCs. Pharmacological inhibition and conditional deletion of Cpt1a in vitro and in vivo leads to altered NSPC behavior, showing that Cpt1a-dependent FAO is required for stem cell maintenance and proper neurogenesis. Strikingly, experimental manipulation of malonyl-CoA, the metabolite that regulates levels of FAO, is sufficient to induce exit from quiescence and to enhance NSPC proliferation. Thus, the data presented here identify a shift in FAO metabolism that governs NSPC behavior and suggest an instructive role for fatty acid metabolism in regulating NSPC activity.
2019-11-15 | PXD005598 | Pride
Project description:Accumulating evidence demonstrates that the gut microbiota affects brain function and behavior, including depressive behavior. Antidepressants are the main drugs used for treatment of depression. We hypothesized that antidepressant treatment could modify gut microbiota which can partially mediate their antidepressant effects. Mice were chronically treated with one of five antidepressants (fluoxetine, escitalopram, venlafaxine, duloxetine or desipramine), and gut microbiota was analyzed, using 16s rRNA gene sequencing. After characterization of differences in the microbiota, chosen bacterial species were supplemented to vehicle and antidepressant-treated mice, and depressive-like behavior was assessed to determine bacterial effects. RNA-seq analysis was performed to determine effects of bacterial treatment in the brain. Antidepressants reduced richness and increased beta diversity of gut bacteria, compared to controls. At the genus level, antidepressants reduced abundances of Ruminococcus, Adlercreutzia, and an unclassified Alphaproteobacteria. To examine implications of the dysregulated bacteria, we chose one of antidepressants (duloxetine) and investigated if its antidepressive effects can be attenuated by simultaneous treatment with Ruminococcus flavefaciens or Adlercreutzia equolifaciens. Supplementation with R. flavefaciens diminished duloxetine-induced decrease in depressive-like behavior, while A. equolifaciens had no such effect. R. flavefaciens treatment induced changes in cortical gene expression, up-regulating genes involved in mitochondrial oxidative phosphorylation, while down-regulating genes involved in neuronal plasticity. Our results demonstrate that various types of antidepressants alter gut microbiota composition, and further implicate a role for R. flavefaciens in alleviating depressive-like behavior.
2019-04-05 | GSE129359 | GEO
Project description:Epidemiological studies suggest that consumption of caffeine, the most commonly consumed psychoactive substances found in coffee, tea or soft drinks reduces the risk of developing Alzheimer’s disease (AD). While previous studies employing transgenic AD mouse models reported on reduced amyloid plaque load or an amelioration of behavioral deficits, there is only limited information on its potential effects on neurodegeneration. In the current study, we assessed whether long-term caffeine consumption affects hippocampal neuron loss and associated behavioral deficits in the Tg4-42 mouse model of AD. Treatment over a 4 months period reduced hippocampal neuron loss, rescued learning and memory deficits and ameliorates impaired neurogenesis. Neuron-specific hippocampal transcriptome analysis revealed an altered expression profile with an up-regulation of genes linked to synaptic function and processes, as well as neural progenitor proliferation. Treatment of 5xFAD mice with the same paradigm also rescued behavioral deficits, however, without affecting extracellular amyloid-beta (Abeta) levels or altered APP processing.
2021-12-13 | GSE183323 | GEO
Project description:The identification of cell-type-specific and early-activated pharmacological targets of antidepressants might help to implement the search for alternative targets to develop drugs with safer side-effect profiles and faster onset of actions. Glia cells are active partners of neurons and blood vessels in supporting a variety of functions such as synaptic communication and blood-brain barrier permeability. Impaired glia cells (astrocytes and microglia cells) characterize postmortem brains of major depressive disorder patients, suggesting that they might be specifically modulated by pharmacological treatments to reverse disease phenotypes. Here, we have treated rat C6 glioma cells, used as a model of astrocytes, with two different classes of antidepressants (desipramine and fluoxetine) and two drugs without antidepressant properties (haloperidol and diazepam) to compare transcriptomes of glia cells after treatment with antidepressants versus drugs without antidepressant properties. To this aim, we used microarrays to detail the global early-activated cell-type-specific gene expression program and identified multiple classes of genes selectively modulated by antidepressants in astrocytes.
2016-11-16 | GSE89873 | GEO
Project description:During adult hippocampal neurogenesis, the majority of newborn cells undergo apoptosis and are rapidly phagocytosed by resident microglia in order to avoid disturbing the surrounding neurons. Here, we propose that phagocytosis is not merely a passive process of corpse removal but has an active role in maintaining adult hippocampal neurogenesis. First, we found that neurogenesis was disrupted in three defective microglial phagocytosis KO models in vivo (P2Y12, MerTK/Axl , GPR34). We then followed an in vitro approach to perform a transcriptomic analysis of microglial phagocytosis and identified genes involved in metabolism, chromatin remodeling, and neurogenesis-related functions. Finally, we determined that the phagocytic microglia secretome limits the production of new neurons both in vivo and in vitro. Our data suggest that reprogrammed phagocytic microglia acts as a sensor of local cell death, modulating the balance between cell proliferation and cell survival in the neurogenic niche, supporting the long-term maintenance of adult hippocampal neurogenesis.
2020-04-09 | GSE129569 | GEO
Project description:We report that the two adult neurogenic niches of the mammalian brain – the dentate gyrus of the hippocampal formation and the subependymal zone of the lateral ventricles - displayed differential vulnerability to increased FoxG1 dosage: high FoxG1 levels severely compromised survival and glutamatergic dentate granule neuron fate acquisition in the hippocampal neurogenic niche, but left neurogenesis of GABAergic neurons in the subependymal zone / olfactory bulb system unaffected. Comparative transcriptomic analyses revealed a significantly higher expression of the apoptosis-linked nuclear receptor Nr4a1 in FoxG1-overexpressing hippocampal neural precursors. Our results reveal differential vulnerability of neuronal subtypes to increased FoxG1 dosage and suggest that activity of a FoxG1/Nr4a1 axis contributes to such subtype-specific response.
2022-03-22 | GSE185315 | GEO