Impact of fluoxetine treatment and folic acid supplementation on the mammary gland transcriptome during peak lactation
Ontology highlight
ABSTRACT: Lactation causes dramatic maternal calcemic adaptations where up to 10% of maternal bone density is mobilized for milk calcium. Serotonin plays a role in regulating this calcemic demand through alterations in DNA methylation. Selective serotonin reuptake inhibitors used to treat peripartum depression exacerbate this signaling. The first objective of this study was to determine the impact of fluoxetine, one of the most popular selective serotonin reuptake inhibitors, on the transcriptome of the mouse mammary gland during peak lactation. The second objective was to determine whether supplementation with folic acid, a well-known methyl donor, would mitigate the gene expression changes induced by fluoxetine.
Project description:Selective serotonin reuptake inhibitors (SSRIs) are one of the most prescribed antidepressant classes in recent decades, with the development of numerous variants. While the primary action of these medications involves the inhibition of serotonin reuptake, the observed therapeutic efficacy exhibits interindividual variability. In order to elucidate the molecular mechanisms underlying their pharmacological actions, this study examined the alteration in the transcriptome following treatment of each SSRI—fluoxetine, sertraline, or citalopram— or vehicle in cultured cortical neurons and the medial prefrontal cortex (mPFC) of mice (Mus musculus, Slc:ICR).
Project description:Assessing the risks of long-term exposure to low doses of pharmaceuticals is an identified research need, particularly for those that may act as neural disruptors in non-vertebrate species. Selective serotonin reuptake inhibitors (SSRIs) act by blocking the re-uptake of serotonin in the nerve synapses, increasing the effective concentration of serotonin in the intra-synaptic space and therefore stimulating serotoninergic neurons. This effect is used worldwide to treat clinical depression in humans, with the consequence of their widespread release into the environment. SSRIs have been found to alter the reproductive physiology of D. magna and other invertebrates in a biphasic way. Low levels of fluoxetine stimulated offspring production in Daphnia magna and Ceriodaphnia dubia at 36 and 50 µg/l, respectively, but higher exposure levels inhibited reproduction in the same species. In this study we explore the hypothesis that SSRI can affect D. magna juvenile developmental rates and offspring production disrupting serotonin activity that is known to regulate carbohydrate and oxidative metabolic pathways. The primary mode of action was tested using transcriptomic analyses of juveniles and adults exposed to SSRIs (fluoxetine 80 ppbs, fluovoxamine 30 ppbs) and serotonin-immunocytochemistry assays of D. magna brains. Reproduction, respirometry and biochemical measurements allowed to related gene and immunological base effects to phenotypic responses.
Project description:Assessing the risks of long-term exposure to low doses of pharmaceuticals is an identified research need, particularly for those that may act as neural disruptors in non-vertebrate species. Selective serotonin reuptake inhibitors (SSRIs) act by blocking the re-uptake of serotonin in the nerve synapses, increasing the effective concentration of serotonin in the intra-synaptic space and therefore stimulating serotoninergic neurons. This effect is used worldwide to treat clinical depression in humans, with the consequence of their widespread release into the environment. SSRIs have been found to alter the reproductive physiology of D. magna and other invertebrates in a biphasic way. Low levels of fluoxetine stimulated offspring production in Daphnia magna and Ceriodaphnia dubia at 36 and 50 µg/l, respectively, but higher exposure levels inhibited reproduction in the same species.
Project description:Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed antidepressant drugs in pregnant women. Given that SSRIs can cross the placental and blood-brain barriers, these drugs potentially affect serotonergic neurotransmission and neurodevelopment in the fetus. Although no gross SSRI-related teratogenic effect has been reported, infants born following prenatal exposure to SSRIs have a higher risk for various behavioral abnormalities. Therefore, we examined the effects of prenatal fluoxetine, the most commonly prescribed SSRI, on social and cognitive behavior in mice. Intriguingly, chronic in utero fluoxetine treatment impaired working memory and social novelty recognition in adult males with augmented spontaneous inhibitory synaptic transmission onto the layer 5 pyramidal neurons in the medial prefrontal cortex (mPFC). Moreover, fast-spiking interneurons in the layer 5 mPFC exhibited enhanced basal intrinsic excitability, augmented serotonin-induced neuronal excitability, and increased inhibitory synaptic transmission onto the layer 5 pyramidal neurons due to augmented 5-HT2A receptor (5-HT2AR) signaling. More importantly, the observed behavioral deficits of in utero fluoxetine-treated mice could be reversed by acute systemic application of 5-HT2AR antagonist. Taken together, our findings support the notion that alterations in serotonin-mediated inhibitory neuronal modulation result in reduced cortical network activities and cognitive impairment following prenatal exposure to SSRIs.
Project description:This study investigates the effects of environmentally-relevant concentrations of fluoxetine (FLX, commercial name: Prozac) on wound healing. Pollution of water systems with pharmaceutical and care products, including antidepressants such as FLX and other selective serotonin reuptake inhibitors, is a growing environmental concern. Environmentally-relevant FLX concentrations are known to impact physiological functions and behaviour of aquatic animals, however, the effects of exposure on humans are currently unknown. Using a combination of human skin biopsies and keratinocyte cell lines, we show that exposure to environmental FLX enhances wound closure. We show dose-dependent increases in wound closure with FLX concentrations from 125 ng/l. We demonstrate that the mechanisms underlying enhanced wound closure are increased cell proliferation and serotonin signalling. Transcriptomic analysis revealed 350 differentially expressed genes after exposure. Downregulated genes were enriched in pathways related to mitochondrial function and metabolism, while upregulated genes were associated with cell proliferation and tissue morphogenesis. Kinase profiling showed altered phosphorylation of kinases related to the MAPK pathway. Consistent with this, phosphoproteomics analyses identified 235 differentially phosphorylated proteins after exposure, with enriched GO terms related to cell cycle, division, and protein biosynthesis. These findings collectively show that exposure to environmental FLX promotes wound healing through modulation of serotonin signalling, gene expression and protein phosphorylation, leading to enhanced cell proliferation. Our results open the door for further research to investigate the effects of environmental FLX on cell metabolism and proliferation, and clinical applications of FLX in the setting of wound healing. We argue that there is an urgent need to develop models that can inform on the risks, and potential benefits, of environmental pollution with selective serotonin reuptake inhibitors.
Project description:Selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine are the most common treatment for major depression. However, approximately 50% of depressed patients fail to achieve an effective treatment response. Understanding how gene expression systems relate to treatment responses may be critical for understanding antidepressant resistance. Transcriptome profiling allows for the simultaneous measurement of expression levels for thousands of genes and the opportunity to utilize this information to determine mechanisms underlying antidepressant treatment responses. However, the best way to relate this immense amount of information to treatment resistance remains unclear. We take a novel approach to this question by examining dentate gyrus transcriptomes from the perspective of a stereotyped fluoxetine-induced gene expression program. Expression programs usually represent stereotyped changes in expression levels that occur as cells transition phenotypes. Fluoxetine will shift transcriptomes so they lie somewhere between a baseline state and a full-response at the end of the program. The position along this fluoxetine-induced gene expression program (program status) was measured using principal components analysis (PCA). The same expression program was initiated in treatment-responsive and resistant mice but treatment response was associated with further progression along the fluoxetine-induced gene expression program. The study of treatment-related differences in gene expression program status represents a novel way to conceptualize differences in treatment responses at a transcriptome level. Understanding how antidepressant-induced gene expression program progression is modulated represents an important area for future research and could guide efforts to develop novel augmentation strategies for antidepressant treatment resistant individuals. 38 samples, 2 dentate regions (dorsal/ventral), 3 groups (control, antidepressant resistant (4 mice), antidepressant responsive (7 mice), untreated (8 mice).
Project description:The goals of this study are to generate and study serotonergic neurons from MDD patients that are selective serotonin reuptake inhibitor (SSRI) remitters and SSRI-nonremitters (NR).
Project description:Selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine are the most common treatment for major depression. However, approximately 50% of depressed patients fail to achieve an effective treatment response. Understanding how gene expression systems relate to treatment responses may be critical for understanding antidepressant resistance. Transcriptome profiling allows for the simultaneous measurement of expression levels for thousands of genes and the opportunity to utilize this information to determine mechanisms underlying antidepressant treatment responses. However, the best way to relate this immense amount of information to treatment resistance remains unclear. We take a novel approach to this question by examining dentate gyrus transcriptomes from the perspective of a stereotyped fluoxetine-induced gene expression program. Expression programs usually represent stereotyped changes in expression levels that occur as cells transition phenotypes. Fluoxetine will shift transcriptomes so they lie somewhere between a baseline state and a full-response at the end of the program. The position along this fluoxetine-induced gene expression program (program status) was measured using principal components analysis (PCA). The same expression program was initiated in treatment-responsive and resistant mice but treatment response was associated with further progression along the fluoxetine-induced gene expression program. The study of treatment-related differences in gene expression program status represents a novel way to conceptualize differences in treatment responses at a transcriptome level. Understanding how antidepressant-induced gene expression program progression is modulated represents an important area for future research and could guide efforts to develop novel augmentation strategies for antidepressant treatment resistant individuals.
Project description:The goals of this study are to generate and study neurons from MDD patients and examine specific aspects of serotonergic neurotransmission in selective serotonin reuptake inhibitor (SSRI) remitters ® and SSRI-nonremitters (NR)
Project description:Recent evidence has suggested that fluoxetine, a serotonin-reuptake inhibitor and emerging environmental contaminant, can have non-targeted effects on metabolism in fish exposed to this waterborne pollutant. Using the highest, environmentally relevant, detectable level of fluoxetine (540 ng/L) we examined the impact of fluoxetine on the miRNA profile in the liver of zebrafish that were both fed and fasted for a period of 7 days. These results were further compared to the miRNA profile of zebrafish fasted and fed for 7 days, which were not exposed to fluoxetine. Results indicated that several miRNA that were involved with downregulating genes/pathways in response to fasting were also upregulated in fish exposed to fluoxetine, irrespective to fasting or feeding. These results suggest fluoxetine can have non-targeted effects on metabolic pathways mediated through miRNA expression. Furthermore, specific miRNA (dre-let-7d & dre-miR-140-5p) were found to target the catalytic subunit (AMPKa1 & AMPKa2, respectively) of AMP-Kinase, a master regulator of metabolism. Using predictive software and qPCR validation, combined with the expression profile of these two miRNA, we were able to establish a significant relationship between the expression of these specific miRNA to the downregulation of AMPKa subunit under the influence of 540 ng/L fluoxetine. Adult, female zebrafish were either fed or fasted for 7 days with and without the presense of 540 ng/L fluoxetine, and livers extracted and miRNA purified for miRNA microaary experiment.