title: Serum Amyloid A3 Gene Expression in Adipocytes is an Indicator of the Interaction with Macrophages.
abstract: The infiltration of macrophages into adipose tissue and their interaction with adipocytes are essential for the chronic low-grade inflammation of obese adipose tissue. In this study, we identified the serum amyloid A3 (Saa3) gene as a key adipocyte-derived factor that is affected by interaction with macrophages. We showed that the Saa3 promoter in adipocytes actually responds to activated macrophages in a co-culture system. Decreasing C/EBPβ abundance in 3T3-L1 adipocytes or point mutation of C/EBPβ elements suppressed the increased promoter activity in response to activated macrophages, suggesting an essential role of C/EBPβ in Saa3 promoter activation. Bioluminescence based on Saa3 promoter activity in Saa3-luc mice was promoted in obese adipose tissue, showing that Saa3 promoter activity is most likely related to macrophage infiltration. This study suggests that the level of expression of the Saa3 gene could be utilized for the number of infiltrated macrophages in obese adipose tissue.
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Sanada
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan.
authors.forename: Rika
authors.initials: R
authors.lastname: Satake
authors.affiliation: Kyushu University Faculty of Dental Science, Fukuoka, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Yamashita
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan.
authors.forename: Sumire
authors.initials: S
authors.lastname: Kanai
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan.
authors.forename: Norihisa
authors.initials: N
authors.lastname: Kato
authors.affiliation: Experimental Rheumatology, Department of Rheumatology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Fons Aj
authors.initials: FA
authors.lastname: van de Loo
authors.affiliation: Kyushu University Faculty of Dental Science, Fukuoka, Japan.
authors.forename: Fusanori
authors.initials: F
authors.lastname: Nishimura
authors.affiliation: Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, USA.
authors.forename: Philipp E
authors.initials: PE
authors.lastname: Scherer
authors.affiliation: Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, 739-8528, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Yanaka
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000378:metabolism; D002450:Cell Communication; D015870:Gene Expression; D020869:Gene Expression Profiling; D057809:HEK293 Cells; D006801:Humans; D008262:Macrophage Activation / Q000235:genetics / Q000276:immunology; D008264:Macrophages / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008954:Models, Biological; D057054:Molecular Imaging; D011401:Promoter Regions, Genetic; D000067996:RAW 264.7 Cells; D000685:Serum Amyloid A Protein / Q000235:genetics*; D059467:Transcriptome
chemical_list: D015415:Biomarkers; D022782:CCAAT-Enhancer-Binding Protein-beta; C076498:Saa3 protein, mouse; D000685:Serum Amyloid A Protein