AMPK-Activated Protein Kinase Suppresses Ccr2 Expression by Inhibiting the NF-κB Pathway in RAW264.7 Macrophages

• Published in: PloS one 2016-01, Vol.11 (1), p.e0147279-e0147279
• Main Authors: Kumase, Fumiaki, Takeuchi, Kimio, Morizane, Yuki, Suzuki, Jun, Matsumoto, Hidetaka, Kataoka, Keiko, Al-Moujahed, Ahmad, Maidana, Daniel E, Miller, Joan W, Vavvas, Demetrios G
• Format: Article
• Language: English
• Subjects: AMP; AMP-activated protein kinase; AMP-Activated Protein Kinases - genetics; AMP-Activated Protein Kinases - metabolism; Angiogenesis; Animals; Biology and Life Sciences; Carbon-carbon composites; CC chemokine receptors; CCR2 protein; Cell activation; Cell Line; Chemokines; Cytokines; Diabetes; Endocrinology; Energy balance; Enzyme Activation - drug effects; Gene Expression Regulation - genetics; Genotype & phenotype; Homeostasis; Inflammation; Inflammation - immunology; Inflammatory bowel disease; Inflammatory diseases; Inhibition; Kinases; Laboratories; Lipopolysaccharides; Macrophage Activation - immunology; Macrophages; Macrophages - immunology; Macrophages - metabolism; Medical schools; Medicine and Health Sciences; Metabolism; Mice; Monocyte chemoattractant protein 1; NF-kappa B - antagonists & inhibitors; NF-kappa B - metabolism; NF-κB protein; Pharmacology; Phosphorylation; Physicians; Proteins; Receptors, CCR2 - biosynthesis; Regulation; Regulatory mechanisms (biology); Research and Analysis Methods; Retina; RNA Interference; RNA, Small Interfering - genetics; Signal Transduction - immunology; siRNA; Tumor Necrosis Factor-alpha - antagonists & inhibitors; Tumor necrosis factor-TNF; Tumor necrosis factor-α
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0147279

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.