title: Avian blood induced intranuclear translocation of STAT3 via the chicken leptin receptor.
abstract: Leptin is a multi-functional adipokine in vertebrates. The leptin gene and protein are found in many vertebrates; however, the existence of leptin in birds remains controversial. Here we detected leptin-like activity in avian blood using chicken leptin receptor (chLEPR) and green fluorescent protein (GFP)-fused chicken signal transducer and activator of transcription (chSTAT3) co-expressed in CHO-K1 cells (CHO-chLEPR/STAT3). We validated that rat serum specifically induces intranuclear migration of GFP-fused chSTAT3 (GFP-chSTAT3) in CHO-chLEPR/STAT3 cells, but not in CHO-K1 cells expressing GFP-STAT3 (CHO-chSTAT3) before testing the avian blood samples. Blood of chickens (Gallus gallus), wild jungle crows (Corvus macrorhynchos), and carrion crows (Corvus corone) accumulated the GFP signal into nuclei, and frequency varied in each blood sample. Western blotting showed that chicken and crow blood samples specifically phosphorylated GFP-chSTAT3 in the chLEPR-transfected cells. These results indicate that avian blood contains a leptin-like molecule that specifically binds to LEPR, suggesting that the leptin system is conserved across all vertebrate classes.
authors.affiliation: College of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan. Electronic address: ohkubo@mx.ibaraki.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ohkubo
authors.affiliation: College of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Hirota
authors.affiliation: College of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan; United Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8538, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Murase
authors.affiliation: College of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan; United Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8538, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Adachi
authors.affiliation: Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nozawa-Takeda
authors.affiliation: Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan.
authors.forename: Shoei
authors.initials: S
authors.lastname: Sugita
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D030161:Avian Proteins / Q000097:blood / Q000378:metabolism*; D016466:CHO Cells; D002467:Cell Nucleus / Q000378:metabolism*; D002645:Chickens; D003412:Cricetulus; D046368:Crows; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D017208:Rats, Wistar; D054411:Receptors, Leptin / Q000097:blood / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D030161:Avian Proteins; D054411:Receptors, Leptin; D011993:Recombinant Fusion Proteins; D050796:STAT3 Transcription Factor; D049452:Green Fluorescent Proteins
keywords: Avian; Bioassay; Leptin; STAT3; Signal transduction