Identification and expression analysis of leptin-regulated immediate early response and late target genes.
Using PC12 cells as an in vitro model system, we have identified a series of transcripts induced through activation of the leptin receptor. On the basis of kinetic studies, two distinct gene sets could be discerned: signal transducer and activator of transciption-3 (STAT-3), suppressor of cytokine signalling-3 (SOCS-3), MT-II (metallothionein-II), the serine/threonine kinase fibroblast-growth-factor-inducible kinase (Fnk) and modulator recognition factor (MRF-1), which are immediate early response genes, and pancreatitis-associated protein I (PAP I), squalene epoxidase, uridine diphosphate glucuronosyltransferase and annexin VIII, which are late induced target genes. At late time points a strong co-stimulation with beta-nerve growth factor or with the adenylate cyclase activator forskolin was observed. To assess the validity of the PC12-cell model system, we examined the effect of leptin administration on the gene transcription of STAT-3, MT-II, Fnk and PAP I in vivo. Leptin treatment of leptin-deficient ob/ob mice increased the STAT-3, SOCS-3, MT-II and Fnk mRNA, and MT-I protein levels in liver, whereas, in jejunum, expression of PAP I mRNA was down-regulated. Furthermore, administration of leptin to starved wild-type mice enhanced the expression of MT-II and Fnk mRNA in liver, but decreased MT-II and PAP I mRNA expression in jejunum. These findings may help to explain the obese phenotype observed in some colonies of MT-I- and MT-II-null mice and/or the observation that leptin protects against tumour-necrosis-factor toxicity in vivo.
Waelput
W
W
Flanders Interuniversity Institute for Biotechnology, Department VIB09, Medical Protein Research, Faculty of Medicine, University of Ghent, Belgium.
Verhee
A
A
Broekaert
D
D
Eyckerman
S
S
Vandekerckhove
J
J
Beattie
J H
JH
Tavernier
J
J
D000209:Acute-Phase Proteins / Q000096:biosynthesis; D000818:Animals; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002352:Carrier Proteins / Q000378:metabolism*; D018797:Cell Cycle Proteins; D005576:Colforsin / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D004357:Drug Synergism; D005260:Female; D005786:Gene Expression Regulation; D017781:Genes, Immediate-Early / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D037181:Lectins, C-Type; D020738:Leptin / Q000494:pharmacology*; D008668:Metallothionein / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D020932:Nerve Growth Factor / Q000494:pharmacology; D016716:PC12 Cells; D000073718:Pancreatitis-Associated Proteins; D014176:Protein Biosynthesis; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis; D011506:Proteins; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D012097:Repressor Proteins; D050796:STAT3 Transcription Factor; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D015534:Trans-Activators / Q000096:biosynthesis; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D000097868:Polo-like Kinases
D000209:Acute-Phase Proteins; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D005576:Colforsin; D004268:DNA-Binding Proteins; D037181:Lectins, C-Type; D020738:Leptin; D008668:Metallothionein; D020932:Nerve Growth Factor; D000073718:Pancreatitis-Associated Proteins; D017346:Protein Serine-Threonine Kinases; D011506:Proteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D012097:Repressor Proteins; D050796:STAT3 Transcription Factor; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C515448:LEPR protein, human; C000612141:REG3A protein, human; C490253:Reg3b protein, mouse; C000612144:Reg3b protein, rat; C106644:SOCS3 protein, human; C494086:STAT3 protein, human; C491411:Socs3 protein, mouse; C491410:Socs3 protein, rat; C494087:Stat3 protein, mouse; C494088:Stat3 protein, rat; C515447:leptin receptor, mouse; C486256:PLK3 protein, human; D000097868:Polo-like Kinases; C486257:Plk3 protein, rat; C093328:Plk3 protein, mouse