Involvement of IRAKs and TRAFs in anti-β₂GPI/β₂GPI-induced tissue factor expression in THP-1 cells

Thromb Haemost. 2011 Dec;106(6):1158-69. doi: 10.1160/TH11-04-0229. Epub 2011 Sep 8.

Abstract

Our previous study has shown that Toll-like receptor 4 (TLR4) and its signalling pathway contribute to anti-β₂-glycoprotein I/β₂-glycoprotein I (anti-β₂GPI/β₂GPI)-induced tissue factor (TF) expression in human acute monocytic leukaemia cell line THP-1 and annexin A2 (ANX2) is involved in this pathway. However, its downstream molecules have not been well explored. In this study, we have established that interleukin-1 receptor-associated kinases (IRAKs) and tumour necrosis factor receptor-associated factors (TRAFs) are crucial downstream molecules of anti-β₂GPI/β₂GPI-induced TLR4 signaling pathway in THP-1 cells and explored the potential mechanisms of their self-regulation. Treatment of THP-1 cells with anti-β₂GPI/β₂GPI complex induced IRAKs and TRAFs expression and activation. Anti-β₂GPI/β₂GPI complex firstly induced expression of IRAK4 and IRAK1, then IRAK1 phosphorylation and last IRAK3 upregulation. In addition, anti-β₂GPI/β₂GPI complex simultaneously and acutely enhanced mRNA levels of TRAF6, TRAF4 and zinc finger protein A20 (A20), while chronically increased A20 protein level. Moreover, anti-β₂GPI/β₂GPI complex-induced IRAKs and TRAFs expression and activation were attenuated by knockdown of ANX2 by infection with ANX2-specific RNA interference lentiviruses (LV-RNAi-ANX2) or by treatment with paclitaxel, which inhibits TLR4 as an antagonist of myeloid differentiation protein 2 (MD-2) ligand. Furthermore, both IRAK1/4 inhibitor and a specific proteasome inhibitor MG-132 could attenuate TRAFs expression as well as TF expression induced by anti-β₂GPI/β₂GPI complex. In conclusion, our results indicate that IRAKs and TRAFs play important roles in anti-β₂GPI/β₂GPI-stimulated TLR4/TF signaling pathway in THP-1 cells and contribute to the pathological processes of antiphospholipid syndrome (APS).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Annexin A2 / genetics
  • Annexin A2 / metabolism*
  • Antibodies / immunology
  • Antibodies / metabolism*
  • Antigen-Antibody Complex / metabolism*
  • Antiphospholipid Syndrome / genetics
  • Antiphospholipid Syndrome / metabolism*
  • Cell Line, Tumor
  • Enzyme Inhibitors / pharmacology
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / genetics
  • Humans
  • Interleukin-1 Receptor-Associated Kinases / metabolism*
  • Leupeptins / pharmacology
  • Monocytes / metabolism*
  • Monocytes / pathology
  • Paclitaxel / pharmacology
  • RNA, Small Interfering / genetics
  • Signal Transduction / drug effects
  • Signal Transduction / genetics
  • TNF Receptor-Associated Factor 4 / genetics
  • TNF Receptor-Associated Factor 4 / metabolism
  • TNF Receptor-Associated Factor 6 / genetics
  • TNF Receptor-Associated Factor 6 / metabolism
  • Thromboplastin / genetics
  • Thromboplastin / metabolism
  • Toll-Like Receptor 4 / metabolism
  • Tumor Necrosis Factor Receptor-Associated Peptides and Proteins / metabolism*
  • beta 2-Glycoprotein I / immunology

Substances

  • ANXA2 protein, human
  • Annexin A2
  • Antibodies
  • Antigen-Antibody Complex
  • Enzyme Inhibitors
  • Leupeptins
  • RNA, Small Interfering
  • TLR4 protein, human
  • TNF Receptor-Associated Factor 4
  • TNF Receptor-Associated Factor 6
  • Toll-Like Receptor 4
  • Tumor Necrosis Factor Receptor-Associated Peptides and Proteins
  • beta 2-Glycoprotein I
  • Thromboplastin
  • IRAK1 protein, human
  • IRAK4 protein, human
  • Interleukin-1 Receptor-Associated Kinases
  • Paclitaxel
  • benzyloxycarbonylleucyl-leucyl-leucine aldehyde