TY - JOUR
T1 - AMPK-activated protein kinase suppresses Ccr2 expression by inhibiting the NF-κB pathway in RAW264.7 macrophages
AU - Kumase, Fumiaki
AU - Takeuchi, Kimio
AU - Morizane, Yuki
AU - Suzuki, Jun
AU - Matsumoto, Hidetaka
AU - Kataoka, Keiko
AU - Al-Moujahed, Ahmad
AU - Maidana, Daniel E.
AU - Miller, Joan W.
AU - Vavvas, Demetrios G.
N1 - Funding Information:
This work was supported, in whole or in part, by Foundation Lions Eye Research Fund (DGV); The Yeatts Family Foundation (DGV, JWM); a 2013 Macula Society Research Grant award (DGV); a Bausch & Lomb Vitreoretinal Fellowship (FK); a Physician Scientist Award (DGV), and a unrestricted grant (JWM) from the Research to Prevent Blindness Foundation; NEI R21EY023079-01A1 (DGV); and NEI Grant EY014104 (MEEI Core Grant). We thank Dr. Kip M Connor of the Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, for insightful discussions.We thank Dr.Wendy Chao for her critical review and support for the manuscript. Flow cytometry was conducted by Randy Huang at the Flow Cytometry facility, Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - 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.
AB - 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.
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U2 - 10.1371/journal.pone.0147279
DO - 10.1371/journal.pone.0147279
M3 - Article
C2 - 26799633
AN - SCOPUS:84958214211
VL - 11
JO - PLoS One
JF - PLoS One
SN - 1932-6203
IS - 1
M1 - e0147279
ER -