title: AMPK-Activated Protein Kinase Suppresses Ccr2 Expression by Inhibiting the NF-κB Pathway in RAW264.7 Macrophages.
abstract: C-C chemokine receptor 2 (Ccr2) is a key pro-inflammatory marker of classic (M1) macrophage activation. Although Ccr2 is known to be expressed both constitutively and inductively, the full regulatory mechanism of its expression remains unclear. AMP-activated protein kinase (AMPK) is not only a master regulator of energy homeostasis but also a central regulator of inflammation. In this study, we sought to assess AMPK's role in regulating RAW264.7 macrophage Ccr2 protein levels in resting (M0) or LPS-induced M1 states. In both M0 and M1 RAW264.7 macrophages, knockdown of the AMPKα1 subunit by siRNA led to increased Ccr2 levels whereas pharmacologic (A769662) activation of AMPK, attenuated LPS-induced increases in Ccr2 expression in an AMPK dependent fashion. The increases in Ccr2 levels by AMPK downregulation were partially reversed by NF-κB inhibition whereas TNF-a inhibition had minimal effects. Our results indicate that AMPK is a negative regulator of Ccr2 expression in RAW264.7 macrophages, and that the mechanism of action of AMPK inhibition of Ccr2 is mediated, in part, through the NF-κB pathway.
authors.affiliation: Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Kumase
authors.affiliation: Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Kimio
authors.initials: K
authors.lastname: Takeuchi
authors.affiliation: Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.|Department of Ophthalmology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Morizane
authors.affiliation: Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.|Department of Ophthalmology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Suzuki
authors.affiliation: Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Matsumoto
authors.affiliation: Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Keiko
authors.initials: K
authors.lastname: Kataoka
authors.affiliation: Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Al-Moujahed
authors.affiliation: Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Maidana
authors.affiliation: Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Joan W
authors.initials: JW
authors.lastname: Miller
authors.affiliation: Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Demetrios G
authors.initials: DG
authors.lastname: Vavvas
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D004789:Enzyme Activation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000235:genetics; D007249:Inflammation / Q000276:immunology; D008070:Lipopolysaccharides; D008262:Macrophage Activation / Q000276:immunology*; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D054390:Receptors, CCR2 / Q000096:biosynthesis*; D015398:Signal Transduction / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors
chemical_list: C515335:Ccr2 protein, mouse; D008070:Lipopolysaccharides; D016328:NF-kappa B; D034741:RNA, Small Interfering; D054390:Receptors, CCR2; D014409:Tumor Necrosis Factor-alpha; C548179:Prkaa1 protein, mouse; D055372:AMP-Activated Protein Kinases