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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

A-769662 treatment also abrogated joint damage and IL-6 expression in AIA.(A) Representative H&E and Safranin O stained sections of knee joints on day 10 of AIA induction in vehicle and A-769662-treated mice, which were treated either at day 0 or day 4 after intraarticular injection of mBSA (n = 5 mice per group). Original magnification 200x. (B) Knee thickness in A-769662-treated mice on day 10 of AIA induction. (C) Sections of knee joints were scored for inflammatory infiltration, bone erosion and cartilage damage. A-769662-treated mice had significantly lower scores than WT. (D) Proteins of joint tissues from naive (n = 3 mice per group) and arthritic mice (n = 5 mice per group) of vehicle and A-769662-treated mice were extracted and analyzed by ELISA for the presence of IL-6. (E) Serum from naive (n = 3 mice per group) and arthritic mice (n = 5 mice per group) of vehicle and A-769662-treated mice was analyzed by ELISA for IL-6. Results are expressed as means ± SEM.* p< 0.05 vs WT mice; ** p<0.01
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pone.0140452.g005: A-769662 treatment also abrogated joint damage and IL-6 expression in AIA.(A) Representative H&E and Safranin O stained sections of knee joints on day 10 of AIA induction in vehicle and A-769662-treated mice, which were treated either at day 0 or day 4 after intraarticular injection of mBSA (n = 5 mice per group). Original magnification 200x. (B) Knee thickness in A-769662-treated mice on day 10 of AIA induction. (C) Sections of knee joints were scored for inflammatory infiltration, bone erosion and cartilage damage. A-769662-treated mice had significantly lower scores than WT. (D) Proteins of joint tissues from naive (n = 3 mice per group) and arthritic mice (n = 5 mice per group) of vehicle and A-769662-treated mice were extracted and analyzed by ELISA for the presence of IL-6. (E) Serum from naive (n = 3 mice per group) and arthritic mice (n = 5 mice per group) of vehicle and A-769662-treated mice was analyzed by ELISA for IL-6. Results are expressed as means ± SEM.* p< 0.05 vs WT mice; ** p<0.01

Mentions: We also studied the effect of the A-769662 in another model of inflammatory arthritis, the antigen induced arthritis (AIA) model, which was shown to be macrophage dependent as well in its effective phase [14]. Clinical and histologic analysis showed a reduction in knee thickness, inflammatory cell infiltration, and significantly decreased joint destruction and cartilage damage in A-769662-treated mice (Fig 5A and 5B). Humoral immunity, tested by the relative levels of mBSA-specific antibodies in sera, was also comparable in all mice treated (data not shown). Importantly, A-769662 treatment not only prevented the onset of arthritis but also successfully suppressed joint damage in mice if treatment was initiated in established disease (Fig 5A and 5B). IL-6 amounts in both joints and serum were also significantly lower in A-769662-treated mice in this model of inflammatory arthritis. (Fig 5C and 5D), confirming the role of AMPK activation in inhibition of IL-6 secretion in inflammation.


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

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

A-769662 treatment also abrogated joint damage and IL-6 expression in AIA.(A) Representative H&E and Safranin O stained sections of knee joints on day 10 of AIA induction in vehicle and A-769662-treated mice, which were treated either at day 0 or day 4 after intraarticular injection of mBSA (n = 5 mice per group). Original magnification 200x. (B) Knee thickness in A-769662-treated mice on day 10 of AIA induction. (C) Sections of knee joints were scored for inflammatory infiltration, bone erosion and cartilage damage. A-769662-treated mice had significantly lower scores than WT. (D) Proteins of joint tissues from naive (n = 3 mice per group) and arthritic mice (n = 5 mice per group) of vehicle and A-769662-treated mice were extracted and analyzed by ELISA for the presence of IL-6. (E) Serum from naive (n = 3 mice per group) and arthritic mice (n = 5 mice per group) of vehicle and A-769662-treated mice was analyzed by ELISA for IL-6. Results are expressed as means ± SEM.* p< 0.05 vs WT mice; ** p<0.01
© Copyright Policy
Related In: Results  -  Collection

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

pone.0140452.g005: A-769662 treatment also abrogated joint damage and IL-6 expression in AIA.(A) Representative H&E and Safranin O stained sections of knee joints on day 10 of AIA induction in vehicle and A-769662-treated mice, which were treated either at day 0 or day 4 after intraarticular injection of mBSA (n = 5 mice per group). Original magnification 200x. (B) Knee thickness in A-769662-treated mice on day 10 of AIA induction. (C) Sections of knee joints were scored for inflammatory infiltration, bone erosion and cartilage damage. A-769662-treated mice had significantly lower scores than WT. (D) Proteins of joint tissues from naive (n = 3 mice per group) and arthritic mice (n = 5 mice per group) of vehicle and A-769662-treated mice were extracted and analyzed by ELISA for the presence of IL-6. (E) Serum from naive (n = 3 mice per group) and arthritic mice (n = 5 mice per group) of vehicle and A-769662-treated mice was analyzed by ELISA for IL-6. Results are expressed as means ± SEM.* p< 0.05 vs WT mice; ** p<0.01
Mentions: We also studied the effect of the A-769662 in another model of inflammatory arthritis, the antigen induced arthritis (AIA) model, which was shown to be macrophage dependent as well in its effective phase [14]. Clinical and histologic analysis showed a reduction in knee thickness, inflammatory cell infiltration, and significantly decreased joint destruction and cartilage damage in A-769662-treated mice (Fig 5A and 5B). Humoral immunity, tested by the relative levels of mBSA-specific antibodies in sera, was also comparable in all mice treated (data not shown). Importantly, A-769662 treatment not only prevented the onset of arthritis but also successfully suppressed joint damage in mice if treatment was initiated in established disease (Fig 5A and 5B). IL-6 amounts in both joints and serum were also significantly lower in A-769662-treated mice in this model of inflammatory arthritis. (Fig 5C and 5D), confirming the role of AMPK activation in inhibition of IL-6 secretion in inflammation.

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