title: Nongenomic, glucocorticoid receptor-mediated regulation of serotonin transporter cell surface expression in embryonic stem cell derived serotonergic neurons.
abstract: Depressive disorders have been linked to the combined dysregulation of the hypothalamus-pituitary-adrenal (HPA)-axis and the serotonergic system. The HPA-axis and serotonergic (5-HT) neurons exert reciprocal regulatory actions. It has been reported that glucocorticoid-glucocorticoid receptor (GR) signaling influences serotonin transporter (5-HTT) transcription but data also points to the fact that 5-HTT expression is regulated nongenomically via redistribution of 5-HTT from the cell surface into intracellular compartments. In order to analyze the acute effects of glucocorticoids on 5-HTT cell surface localization we differentiated serotonergic neurons from mouse embryonic stem (ES) cells derived from the C57BL/6N blastocysts. These postmitotic 5-HT neurons express all relevant serotonergic markers following the application of a growth factor-based differentiation protocol. Increasing concentrations of the GR agonist dexamethasone (Dex) resulted in enhanced, dose-dependent 5-HTT cell surface localization in the presence of the protein synthesis inhibitor cycloheximide already 1h after incubation. Inhibition of GR function by the specific GR-antagonist mifepristone abolished the increase in 5-HTT cell surface localization. Hence, our data account for a nongenomic upregulation of 5-HTT cell surface expression by glucocorticoid-GR interaction which likely constitutes a rapid physiological response to increased levels of glucocorticoids as seen during stress. Taken together, we provide a cellular model to analyze and dissect glucocorticoid-5HTT interactions on a molecular level that corresponds to in vivo animal models using C57BL/6N mice.
authors.affiliation: Department of Psychiatry and Psychotherapy, Biochemical Laboratory, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, J5, 68159 Mannheim, Germany. Electronic address: thorsten.lau@zi-mannheim.de.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Lau
authors.forename: Felix
authors.initials: F
authors.lastname: Heimann
authors.forename: Dusan
authors.initials: D
authors.lastname: Bartsch
authors.forename: Patrick
authors.initials: P
authors.lastname: Schloss
authors.forename: Tillmann
authors.initials: T
authors.lastname: Weber
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D015870:Gene Expression; D051379:Mice; D008810:Mice, Inbred C57BL; D021381:Protein Transport; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism*; D059326:Serotonergic Neurons / Q000166:cytology / Q000378:metabolism*; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism*
chemical_list: D011965:Receptors, Glucocorticoid; D050486:Serotonin Plasma Membrane Transport Proteins
keywords: Embryonic stem cells; Glucocorticoid receptor; Nongenomic regulation; Serotonergic neurons; Serotonin transporter