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Annexin A1 released from apoptotic cells acts through formyl peptide receptors to dampen inflammatory monocyte activation via JAK/STAT/SOCS signalling.

Pupjalis D, Goetsch J, Kottas DJ, Gerke V, Rescher U - EMBO Mol Med (2011)

Bottom Line: Supernatants from apoptotic neutrophils or the annexin A1 peptidomimetic Ac2-26 significantly reduced IL-6 signalling and the release of TNF-α from endotoxin-challenged monocytes.Ac2-26 activated STAT3 in a JAK-dependent manner, resulting in upregulated SOCS3 levels, and depletion of SOCS3 reversed the Ac2-26-mediated inhibition of IL-6 signalling.This identifies annexin A1 as part of the anti-inflammatory pattern of apoptotic cells and links the activation of FPRs to established signalling pathways triggering anti-inflammatory responses.

View Article: PubMed Central - PubMed

Affiliation: Centre for Molecular Biology of Inflammation, and Interdisciplinary Clinical Research Centre, Institute of Medical Biochemistry, University of Muenster, Muenster, Germany.

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The annexin A1 peptidomimetic Ac2-26 triggers STAT3 phosphorylation in a FPR-dependent mannerActivation of STAT3 by Ac2-26. Monocytes were treated with Ac2-26 for the indicated times and tyrosine phosphorylation of STAT3 was detected by immunoblotting with the anti-pTYR705-STAT3 antibody. Probing for total STAT3 and tubulin served to visualize equal loading.To ensure the specificity of annexin A1 activation, monocytes were incubated for 10 min with the LPS antagonist polymyxin B prior to stimulation with either LPS or Ac2-26.Involvement of FPRs in the Ac2-26-mediated STAT3 activation. STAT3 phosphorylation in response to Ac2-26 was investigated in the presence of the pan-FPR inhibitor Boc2 by Western blot analysis of lysates of the appropriately treated monocytes. Representative immunoblots of at least three independent experiments are shown.
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fig04: The annexin A1 peptidomimetic Ac2-26 triggers STAT3 phosphorylation in a FPR-dependent mannerActivation of STAT3 by Ac2-26. Monocytes were treated with Ac2-26 for the indicated times and tyrosine phosphorylation of STAT3 was detected by immunoblotting with the anti-pTYR705-STAT3 antibody. Probing for total STAT3 and tubulin served to visualize equal loading.To ensure the specificity of annexin A1 activation, monocytes were incubated for 10 min with the LPS antagonist polymyxin B prior to stimulation with either LPS or Ac2-26.Involvement of FPRs in the Ac2-26-mediated STAT3 activation. STAT3 phosphorylation in response to Ac2-26 was investigated in the presence of the pan-FPR inhibitor Boc2 by Western blot analysis of lysates of the appropriately treated monocytes. Representative immunoblots of at least three independent experiments are shown.

Mentions: To determine directly whether annexin A1 is involved in the process of anti-inflammatory activation, we incubated monocytes for various periods of time with the Ac2-26 peptidomimetic and monitored STAT3 activation. The annexin A1 N-terminal peptide transiently activated STAT3 phosphorylation in a dose- and time-dependent manner. Phosphorylation of STAT3 tyrosine 705 was robustly detected upon 60 min of Ac2-26 stimulation and returned to basal levels at later time points (Fig 4A), thus again mirroring the effect of total apoptotic PMN supernatants. No evidence for activation of STATs 1, 2 or 5 was found in the samples (not shown). To rule out that the observed STAT3 activation was due to a contamination with bacterial endotoxins (Benkhart et al, 2000; Carl et al, 2004), activation with either LPS or Ac2-26 was carried out in the presence of the LPS inhibitor polymyxin B. As shown in Fig 4B, polymyxin B completely inhibited the LPS-induced STAT3 tyrosine phosphorylation, whereas STAT3 activation by Ac2-26 was unaffected, confirming that activation by the annexin A1 peptide was specific.


Annexin A1 released from apoptotic cells acts through formyl peptide receptors to dampen inflammatory monocyte activation via JAK/STAT/SOCS signalling.

Pupjalis D, Goetsch J, Kottas DJ, Gerke V, Rescher U - EMBO Mol Med (2011)

The annexin A1 peptidomimetic Ac2-26 triggers STAT3 phosphorylation in a FPR-dependent mannerActivation of STAT3 by Ac2-26. Monocytes were treated with Ac2-26 for the indicated times and tyrosine phosphorylation of STAT3 was detected by immunoblotting with the anti-pTYR705-STAT3 antibody. Probing for total STAT3 and tubulin served to visualize equal loading.To ensure the specificity of annexin A1 activation, monocytes were incubated for 10 min with the LPS antagonist polymyxin B prior to stimulation with either LPS or Ac2-26.Involvement of FPRs in the Ac2-26-mediated STAT3 activation. STAT3 phosphorylation in response to Ac2-26 was investigated in the presence of the pan-FPR inhibitor Boc2 by Western blot analysis of lysates of the appropriately treated monocytes. Representative immunoblots of at least three independent experiments are shown.
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Related In: Results  -  Collection

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fig04: The annexin A1 peptidomimetic Ac2-26 triggers STAT3 phosphorylation in a FPR-dependent mannerActivation of STAT3 by Ac2-26. Monocytes were treated with Ac2-26 for the indicated times and tyrosine phosphorylation of STAT3 was detected by immunoblotting with the anti-pTYR705-STAT3 antibody. Probing for total STAT3 and tubulin served to visualize equal loading.To ensure the specificity of annexin A1 activation, monocytes were incubated for 10 min with the LPS antagonist polymyxin B prior to stimulation with either LPS or Ac2-26.Involvement of FPRs in the Ac2-26-mediated STAT3 activation. STAT3 phosphorylation in response to Ac2-26 was investigated in the presence of the pan-FPR inhibitor Boc2 by Western blot analysis of lysates of the appropriately treated monocytes. Representative immunoblots of at least three independent experiments are shown.
Mentions: To determine directly whether annexin A1 is involved in the process of anti-inflammatory activation, we incubated monocytes for various periods of time with the Ac2-26 peptidomimetic and monitored STAT3 activation. The annexin A1 N-terminal peptide transiently activated STAT3 phosphorylation in a dose- and time-dependent manner. Phosphorylation of STAT3 tyrosine 705 was robustly detected upon 60 min of Ac2-26 stimulation and returned to basal levels at later time points (Fig 4A), thus again mirroring the effect of total apoptotic PMN supernatants. No evidence for activation of STATs 1, 2 or 5 was found in the samples (not shown). To rule out that the observed STAT3 activation was due to a contamination with bacterial endotoxins (Benkhart et al, 2000; Carl et al, 2004), activation with either LPS or Ac2-26 was carried out in the presence of the LPS inhibitor polymyxin B. As shown in Fig 4B, polymyxin B completely inhibited the LPS-induced STAT3 tyrosine phosphorylation, whereas STAT3 activation by Ac2-26 was unaffected, confirming that activation by the annexin A1 peptide was specific.

Bottom Line: Supernatants from apoptotic neutrophils or the annexin A1 peptidomimetic Ac2-26 significantly reduced IL-6 signalling and the release of TNF-α from endotoxin-challenged monocytes.Ac2-26 activated STAT3 in a JAK-dependent manner, resulting in upregulated SOCS3 levels, and depletion of SOCS3 reversed the Ac2-26-mediated inhibition of IL-6 signalling.This identifies annexin A1 as part of the anti-inflammatory pattern of apoptotic cells and links the activation of FPRs to established signalling pathways triggering anti-inflammatory responses.

View Article: PubMed Central - PubMed

Affiliation: Centre for Molecular Biology of Inflammation, and Interdisciplinary Clinical Research Centre, Institute of Medical Biochemistry, University of Muenster, Muenster, Germany.

Show MeSH