Angiotensin II Type-2 receptors modulate inflammation through signal transducer and activator of transcription proteins 3 phosphorylation and TNFα production

J Interferon Cytokine Res. 2011 Jun;31(6):471-4. doi: 10.1089/jir.2010.0043. Epub 2011 Feb 2.

Abstract

Angiotensin subtype-1 receptor (AT(1)R) influences inflammatory processes through enhancing signal transducer and activator of transcription proteins 3 (STAT3) signal transduction, resulting in increased tumor necrosis factor-α (TNF-α) production. Although angiotensin subtype-2 receptor (AT(2)R), in general, antagonizes AT(1)R-stimulated activity, it is not known if AT(2)R has any anti-inflammatory effects. In this study, we tested the hypothesis that AT(2)R activation plays an anti-inflammatory role by reducing STAT3 phosphorylation and TNF-α production. Changes in AT(2)R expression, TNF-α production, and STAT3 phosphorylation were quantified by Western blotting, Bio-Plex cytokine, and phosphoprotein cellular signaling assays in PC12W cells that express AT(2)R but not AT(1)R, in response to the AT(2)R agonist, CGP-42112 (CGP, 100 nm), or AT(2)R antagonist PD-123319 (PD, 1 μm). A 100% increase in AT(2)R expression in response to stimulation with its agonist CGP was observed. Further, AT(2)R activation reduced TNF-α production by 39% and STAT3 phosphorylation by 83%. In contrast, PD decreased AT(2)R expression by 76%, increased TNF-α production by 84%, and increased STAT3 phosphorylation by 67%. These findings suggest that increased AT(2)R expression may play a role in the observed decrease in inflammatory pathway activation through decreased TNF-α production and STAT3 signaling. Restoration of AT(2)R expression and/or its activation constitute a potentially novel therapeutic target for the management of inflammatory processes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II Type 2 Receptor Blockers / pharmacology
  • Animals
  • Cell Line, Tumor
  • Gene Expression Regulation / drug effects
  • Imidazoles / pharmacology
  • Immunomodulation
  • Inflammation
  • Oligopeptides / pharmacology
  • Phosphorylation / drug effects
  • Pyridines / pharmacology
  • Rats
  • Receptor, Angiotensin, Type 1 / deficiency
  • Receptor, Angiotensin, Type 2 / agonists
  • Receptor, Angiotensin, Type 2 / biosynthesis*
  • Receptor, Angiotensin, Type 2 / genetics
  • STAT3 Transcription Factor / biosynthesis*
  • STAT3 Transcription Factor / genetics
  • Signal Transduction / drug effects
  • Tumor Necrosis Factor-alpha / biosynthesis*
  • Tumor Necrosis Factor-alpha / genetics

Substances

  • Angiotensin II Type 2 Receptor Blockers
  • Imidazoles
  • Oligopeptides
  • Pyridines
  • Receptor, Angiotensin, Type 1
  • Receptor, Angiotensin, Type 2
  • STAT3 Transcription Factor
  • Tumor Necrosis Factor-alpha
  • CGP 42112A
  • PD 123319