title: Lithium increases melanin-concentrating hormone mRNA stability and inhibits tyrosine hydroxylase gene expression in PC12 cells.
abstract: Melanin-concentrating hormone (MCH) is a cyclic peptide involved in the regulation of food-intake behaviour and stress response in mammals. Expression of the MCH gene predominates in hypothalamic neurons. Mechanisms governing the regulation of expression of MCH gene in established cell lines were not explored yet. Here, we analysed the actions of nerve growth factor (NGF), dexamethasone, forskolin and lithium on MCH mRNA levels in the PC12 pheochromocytoma cell line. We compared them with those observed on tyrosine hydroxylase (TH) mRNA, constitutively expressed in PC12 cells, and neurotensin (NT) mRNA, taken as a control. In untreated cells, MCH RNA species of high molecular weight were found. Exposure of cells at a combination of NGF and lithium resulted in decreased expression of these MCH RNAs and in the transient production of mature MCH mRNA. Strikingly, after short exposure of PC12 cells to NGF, lithium per se elicited a marked increase in MCH mRNA levels whilst it exerted a potent inhibitory action on TH mRNA expression. Detailed investigations revealed that lithium enhanced MCH mRNA expression through post-transcriptional mechanisms whereas it regulated TH gene expression mainly at the level of transcription. These results demonstrate that lithium, an agent widely used for treatment of manic depressive illness, can exert an opposite effect on MCH and TH mRNA production in PC12 cells. The MCH gene system in NGF-treated PC12 cells provides a good opportunity for studying the effect of lithium on gene expression at post-transcriptional levels in a neuron-like cellular model.
authors.affiliation: Institut de Pharmacologie Moléculaire et Cellulaire, UPR 411 CNRS, Université de Nice Sophia-Antipolis, Valbonne, France.
authors.forename: F
authors.initials: F
authors.lastname: Presse
authors.forename: B
authors.initials: B
authors.lastname: Cardona
authors.forename: L
authors.initials: L
authors.lastname: Borsu
authors.forename: J L
authors.initials: JL
authors.lastname: Nahon
mesh_terms: D000310:Adrenal Gland Neoplasms; D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D015342:DNA Probes; D003907:Dexamethasone / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D007028:Hypothalamic Hormones / Q000096:biosynthesis*; D007700:Kinetics; D018021:Lithium Chloride / Q000494:pharmacology*; D008543:Melanins / Q000096:biosynthesis*; D009414:Nerve Growth Factors / Q000494:pharmacology; D009496:Neurotensin / Q000096:biosynthesis; D016716:PC12 Cells; D010673:Pheochromocytoma; D010907:Pituitary Hormones / Q000096:biosynthesis*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D014158:Transcription, Genetic / Q000187:drug effects; D014446:Tyrosine 3-Monooxygenase / Q000096:biosynthesis*
chemical_list: D015342:DNA Probes; D007028:Hypothalamic Hormones; D008543:Melanins; D009414:Nerve Growth Factors; D010907:Pituitary Hormones; D012333:RNA, Messenger; D005576:Colforsin; D009496:Neurotensin; C019463:melanin-concentrating hormone; D003907:Dexamethasone; D014446:Tyrosine 3-Monooxygenase; D018021:Lithium Chloride