Neurotensin Induces Tyrosine Hydroxylase Gene Activation through Nitric Oxide and Protein Kinase C Signaling Pathways
- 1Institut National de la Santé et de la Recherche Médicale U339, Hôpital Saint-Antoine, Paris, France (M.N., W.R., P.F.); and 2Centre National de la Recherche Scientifique Unité Mixte Recherche 9223, Hôpital de la Pitié-Salpétrière, Paris, France (J.J.R., J.M.)
- Dr. P. Forgez, INSERM U339, Hôpital Saint-Antoine, 184 rue du Faubourg St-Antoine 75012 Paris, France. E-mail: forgez{at}adr.st-antoine.inserm.fr
Abstract
The regulation of tyrosine hydroxylase (TH) represents an effective means to control the level of catecholamines, because TH is the major limiting enzyme of monoamine biosynthesis. The neuropeptide neurotensin (NT) is a neuromodulator of dopaminergic systems, and a direct interaction between NT and TH expression has been demonstrated in vivo and in vitro. In the present work, the molecular mechanisms and signaling pathways responsible for TH gene activation have been explored. In N1E-115 cells, NT agonist induced a TH protein level increase, correlating with a significant increase in TH mRNA abundance. This cellular response was the result of TH promoter activation, via c-fos and Jun D binding at the AP-1 responsive element. Using selective protein kinase C and nitric oxide synthase inhibitors, we demonstrate, by quantitative reverse transcription-polymerase chain reaction, gel shift, and protein assays, that TH gene activation by NT agonist requires both protein kinase C stimulation and nitric oxide production. The two pathways exert distinct roles; whereas nitric oxide synthase inhibitors blocked c-fos expression, protein kinase C inhibitors blocked that of Jun D. The requirement for two distinct and concomitant pathways by NT demonstrates a very fine level of control of specificity on TH gene activation.
Footnotes
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↵1 Present address: Laboratoire de Pharmacologie Experimentale, Université Catholique de Louvain, 54.10 Avenue Hippocrate 54, 1200 Bruxelles, Belgique.
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M.N. was supported by a fellowship from the Moroccan government and from INSERM.
- Abbreviations:
- TH
- tyrosine hydroxylase [tyrosine 3-monooxygenase: l-tyrosine, tetrahydropteridin:oxygen oxidoreductase (3-hydroxylating)]
- NT
- neurotensin
- NT-1 receptor
- high affinity neurotensin receptor
- JMV 449
- H-LysΨ(CH2NH)Lys-Pro-Tyr-Ile-Leu-OH
- AP
- activator protein
- PKC
- protein kinase C
- NO
- nitric oxide
- FCS
- fetal calf serum
- DMSO
- dimethyl sulfoxide
- RT
- reverse transcriptase
- PCR
- polymerase chain reaction
- DTT
- dithiothreitol
- Gö6976
- 12-(2-cyanoethyl)-6,7,12,13-tetrahydro-13-methyl-5-oxo-5H-indolo(2,3-a)pyrrolo(3,4-c)-carbazole
- GF-109203X
- bisindoylmaleimide I
- l-NMMA
- N-monomethyl-l-arginine, monoacetate salt
- l-NAME
- N-nitro-l-arginine methyl ester, Hydrochloride
- d-NAME
- N-nitro-d-arginine, methyl ester, hydrochloride
- RLU
- relative light units
- H89
- N-[2-((bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamide, 2HCl]
- H7
- [1–5(isoquinolinesulfonyl)-2-methylpiperazine, 2HCl]
- AG 1478
- 4-(3-chloroanilino)-6,7-dimthoxyquinazoline
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- Received December 21, 2001.
- Accepted May 24, 2002.
- The American Society for Pharmacology and Experimental Therapeutics
