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AMPK Activation by A-769662 Controls IL-6 Expression in Inflammatory Arthritis.

Guma M, Wang Y, Viollet B, Liu-Bryan R - PLoS ONE (2015)

Bottom Line: Many studies have suggested that AMPK activation exert significant anti-inflammatory and immunosuppressive effects.The effect of A-769662 on bone marrow derived macrophage (BMDM) response to stimulation with TLR2 and TLR4 agonists was tested in vitro.IL-6 expression at both mRNA and protein levels, phosphorylation of p65 NF-κB and MAPK phosphorylation were inhibited by A-769662 in BMDMs stimulated with either TLR2 or TLR4 agonists.

View Article: PubMed Central - PubMed

Affiliation: Division of Rheumatology, Allergy and Immunology, UC San Diego School of Medicine, La Jolla, California, United States of America.

ABSTRACT

Objective: AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase critically involved in the regulation of cellular energy homeostasis. It is a central regulator of both lipid and glucose metabolism. Many studies have suggested that AMPK activation exert significant anti-inflammatory and immunosuppressive effects. In this study, we assessed whether targeted activation of AMPK inhibits inflammatory arthritis in vivo.

Methods: We tested the effect of A-769662, a specific AMPK agonist (60mg/kg/bid) in mouse models of antigen-induced arthritis (AIA) and passive K/BxN serum-induced arthritis. The passive K/BxN serum-induced arthritis model was also applied to AMPKα1-deficient mice. Joints were harvested and subjected to histological analysis. IL-6 expression was measured in both joint tissues and sera by ELISA. The effect of A-769662 on bone marrow derived macrophage (BMDM) response to stimulation with TLR2 and TLR4 agonists was tested in vitro.

Results: AMPK activation by A-769662 reduced inflammatory infiltration and joint damage in both mouse models. IL-6 expression in serum and arthritic joints was significantly decreased in A-769662-treated mice. AMPKα1 deficient mice mildly elicited an increase of clinical arthritis. IL-6 expression at both mRNA and protein levels, phosphorylation of p65 NF-κB and MAPK phosphorylation were inhibited by A-769662 in BMDMs stimulated with either TLR2 or TLR4 agonists.

Conclusions: AMPK activation by specific AMPK agonist A-769662 suppressed inflammatory arthritis in mice as well as IL-6 expression in serum and arthritic joints. These data suggest that targeted activation of AMPK has a potential to be an effective therapeutic strategy for IL-6 dependent inflammatory arthritis.

No MeSH data available.


Related in: MedlinePlus

AMPKα1 deficiency mildly increased clinical arthritis in K/BxN arthritis.WT mice and AMPKα1 KO were injected with 100μl serum from adult K/BxN mice on day 0 to induce arthritis. (A) Clinical score and ankle thickness in WT and AMPKα1 deficient animals (n = 5 mice per group) at day 6 after arthritis induction. (B) Proteins of joint tissues from naive (n = 4 mice per group) and arthritic mice (n = 4 mice per group) of WT and AMPKα1 deficient mice were extracted at day 6 after arthritis induction and analyzed by ELISA for the presence of IL-6. (C) Clinical score in WT animals (black circles, n = 6) and AMPKα1 animals (black squares, n = 6). Values are means ± SEM. * = p<0.05; ** = p<0.01.
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pone.0140452.g006: AMPKα1 deficiency mildly increased clinical arthritis in K/BxN arthritis.WT mice and AMPKα1 KO were injected with 100μl serum from adult K/BxN mice on day 0 to induce arthritis. (A) Clinical score and ankle thickness in WT and AMPKα1 deficient animals (n = 5 mice per group) at day 6 after arthritis induction. (B) Proteins of joint tissues from naive (n = 4 mice per group) and arthritic mice (n = 4 mice per group) of WT and AMPKα1 deficient mice were extracted at day 6 after arthritis induction and analyzed by ELISA for the presence of IL-6. (C) Clinical score in WT animals (black circles, n = 6) and AMPKα1 animals (black squares, n = 6). Values are means ± SEM. * = p<0.05; ** = p<0.01.

Mentions: We finally induced arthritis in AMPKα1 deficient mice. AMPKα1 is the predominant isoform in macrophages. Although clinical scores (score at day 6 was 3.4 ± 0.6 and 5.6 ± 0.48, and ankle thickness was 0.43 ± 0.26 and 0.76 ± 0.21 for WT and AMPKα1 deficient mice respectively, Fig 6A) and amounts of IL-6 in the joints at day 6 (Fig 6B), were increased in the AMPKα1 deficient mice, clinical scores at later time points (Fig 6C) and histologically score at day 8 (data not shown) were not significantly different between WT and AMPKα1 deficient mice, suggesting that inhibition of both AMPKα isoforms may be needed to sufficiently enhance inflammatory arthritis as other cell types, and not only macrophages, may also play an important role in this murine model.


AMPK Activation by A-769662 Controls IL-6 Expression in Inflammatory Arthritis.

Guma M, Wang Y, Viollet B, Liu-Bryan R - PLoS ONE (2015)

AMPKα1 deficiency mildly increased clinical arthritis in K/BxN arthritis.WT mice and AMPKα1 KO were injected with 100μl serum from adult K/BxN mice on day 0 to induce arthritis. (A) Clinical score and ankle thickness in WT and AMPKα1 deficient animals (n = 5 mice per group) at day 6 after arthritis induction. (B) Proteins of joint tissues from naive (n = 4 mice per group) and arthritic mice (n = 4 mice per group) of WT and AMPKα1 deficient mice were extracted at day 6 after arthritis induction and analyzed by ELISA for the presence of IL-6. (C) Clinical score in WT animals (black circles, n = 6) and AMPKα1 animals (black squares, n = 6). Values are means ± SEM. * = p<0.05; ** = p<0.01.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4608670&req=5

pone.0140452.g006: AMPKα1 deficiency mildly increased clinical arthritis in K/BxN arthritis.WT mice and AMPKα1 KO were injected with 100μl serum from adult K/BxN mice on day 0 to induce arthritis. (A) Clinical score and ankle thickness in WT and AMPKα1 deficient animals (n = 5 mice per group) at day 6 after arthritis induction. (B) Proteins of joint tissues from naive (n = 4 mice per group) and arthritic mice (n = 4 mice per group) of WT and AMPKα1 deficient mice were extracted at day 6 after arthritis induction and analyzed by ELISA for the presence of IL-6. (C) Clinical score in WT animals (black circles, n = 6) and AMPKα1 animals (black squares, n = 6). Values are means ± SEM. * = p<0.05; ** = p<0.01.
Mentions: We finally induced arthritis in AMPKα1 deficient mice. AMPKα1 is the predominant isoform in macrophages. Although clinical scores (score at day 6 was 3.4 ± 0.6 and 5.6 ± 0.48, and ankle thickness was 0.43 ± 0.26 and 0.76 ± 0.21 for WT and AMPKα1 deficient mice respectively, Fig 6A) and amounts of IL-6 in the joints at day 6 (Fig 6B), were increased in the AMPKα1 deficient mice, clinical scores at later time points (Fig 6C) and histologically score at day 8 (data not shown) were not significantly different between WT and AMPKα1 deficient mice, suggesting that inhibition of both AMPKα isoforms may be needed to sufficiently enhance inflammatory arthritis as other cell types, and not only macrophages, may also play an important role in this murine model.

Bottom Line: Many studies have suggested that AMPK activation exert significant anti-inflammatory and immunosuppressive effects.The effect of A-769662 on bone marrow derived macrophage (BMDM) response to stimulation with TLR2 and TLR4 agonists was tested in vitro.IL-6 expression at both mRNA and protein levels, phosphorylation of p65 NF-κB and MAPK phosphorylation were inhibited by A-769662 in BMDMs stimulated with either TLR2 or TLR4 agonists.

View Article: PubMed Central - PubMed

Affiliation: Division of Rheumatology, Allergy and Immunology, UC San Diego School of Medicine, La Jolla, California, United States of America.

ABSTRACT

Objective: AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase critically involved in the regulation of cellular energy homeostasis. It is a central regulator of both lipid and glucose metabolism. Many studies have suggested that AMPK activation exert significant anti-inflammatory and immunosuppressive effects. In this study, we assessed whether targeted activation of AMPK inhibits inflammatory arthritis in vivo.

Methods: We tested the effect of A-769662, a specific AMPK agonist (60mg/kg/bid) in mouse models of antigen-induced arthritis (AIA) and passive K/BxN serum-induced arthritis. The passive K/BxN serum-induced arthritis model was also applied to AMPKα1-deficient mice. Joints were harvested and subjected to histological analysis. IL-6 expression was measured in both joint tissues and sera by ELISA. The effect of A-769662 on bone marrow derived macrophage (BMDM) response to stimulation with TLR2 and TLR4 agonists was tested in vitro.

Results: AMPK activation by A-769662 reduced inflammatory infiltration and joint damage in both mouse models. IL-6 expression in serum and arthritic joints was significantly decreased in A-769662-treated mice. AMPKα1 deficient mice mildly elicited an increase of clinical arthritis. IL-6 expression at both mRNA and protein levels, phosphorylation of p65 NF-κB and MAPK phosphorylation were inhibited by A-769662 in BMDMs stimulated with either TLR2 or TLR4 agonists.

Conclusions: AMPK activation by specific AMPK agonist A-769662 suppressed inflammatory arthritis in mice as well as IL-6 expression in serum and arthritic joints. These data suggest that targeted activation of AMPK has a potential to be an effective therapeutic strategy for IL-6 dependent inflammatory arthritis.

No MeSH data available.


Related in: MedlinePlus