title: Activation of transcription factors STAT1 and STAT5 in the mouse median eminence after systemic ciliary neurotrophic factor administration.
abstract: Exogenously administered ciliary neurotrophic factor (CNTF) causes weight loss in obese rodents and humans through leptin-like activation of the Jak-STAT3 signaling pathway in hypothalamic arcuate neurons. Here we report for the first time that 40min after acute systemic treatment, rat recombinant CNTF (intraperitoneal injection of 0.3mg/kg of body weight) induced nuclear translocation of the tyrosine-phosphorylated forms of STAT1 and STAT5 in the mouse median eminence and other circumventricular organs, including the vascular organ of the lamina terminalis and the subfornical organ. In the tuberal hypothalamus of treated mice, specific nuclear immunostaining for phospo-STAT1 and phospho-STAT5 was detected in ependymal cells bordering the third ventricle floor and lateral recesses, and in median eminence cells. Co-localization studies documented STAT1 and STAT5 activation in median eminence β-tanycytes and underlying radial glia-like cells. A few astrocytes in the arcuate nucleus responded to CNTF by STAT5 activation. The vast majority of median eminence tanycytes and radial glia-like cells showing phospho-STAT1 and phospho-STAT5 immunoreactivity were also positive for phospho-STAT3. In contrast, STAT3 was the sole STAT isoform activated by CNTF in arcuate nucleus and median eminence neurons. Finally, immunohistochemical evaluation of STAT activation 20, 40, 80, and 120min from the injection demonstrated that cell activation was accompanied by c-Fos expression. Collectively, our findings show that CNTF activates STAT3, STAT1, and STAT5 in vivo. The distinctive activation pattern of these STAT isoforms in the median eminence may disclose novel targets and pathways through which CNTF regulates food intake.
authors.affiliation: Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Ilenia
authors.initials: I
authors.lastname: Severi
authors.affiliation: Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Senzacqua
authors.affiliation: Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Mondini
authors.affiliation: Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Fazioli
authors.affiliation: Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy; Center of Obesity, Università Politecnica delle Marche-United Hospitals, Ancona, Italy.
authors.forename: Saverio
authors.initials: S
authors.lastname: Cinti
authors.affiliation: Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy. Electronic address: a.giordano@univpm.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Giordano
mesh_terms: D000818:Animals; D019440:Anti-Obesity Agents / Q000008:administration & dosage*; D001111:Arcuate Nucleus of Hypothalamus / Q000187:drug effects / Q000378:metabolism; D015153:Blotting, Western; D002491:Central Nervous System Agents / Q000008:administration & dosage*; D020934:Ciliary Neurotrophic Factor / Q000008:administration & dosage*; D007150:Immunohistochemistry; D008297:Male; D008473:Median Eminence / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D018613:Microscopy, Confocal; D009457:Neuroglia / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D050794:STAT1 Transcription Factor / Q000378:metabolism*; D050799:STAT5 Transcription Factor / Q000378:metabolism*; D013997:Time Factors
chemical_list: D019440:Anti-Obesity Agents; D002491:Central Nervous System Agents; D020934:Ciliary Neurotrophic Factor; D016760:Proto-Oncogene Proteins c-fos; D050794:STAT1 Transcription Factor; D050799:STAT5 Transcription Factor; C494080:Stat1 protein, mouse
keywords: Cytokines; Energy balance; Hypothalamus; Obesity; Signal transducers and activator of transcription; Tanycytes