Different Toll-like receptor agonists induce distinct macrophage responses

J Leukoc Biol. 2001 Jun;69(6):1036-44.

Abstract

We previously reported that gram-negative bacterial lipopolysaccharide (LPS) activates cells via Toll-like receptor (TLR) 4, whereas the mycobacterial cell wall glycolipid lipoarabinomannan (LAM) activates cells via TLR2. We also identified a secreted TLR2 agonist activity in short-term culture filtrates of Mycobacterium tuberculosis bacilli, termed soluble tuberculosis factor (STF). Here we show that STF contains mannosylated phosphatidylinositol (PIM) and that purified PIM possesses TLR2 agonist activity. Stimulation of RAW 264.7 macrophages by LPS, LAM, STF, and PIM rapidly activated nuclear factor (NF)-kappaB, activator protein-1 (AP-1), and mitogen-activated protein (MAP) kinases. These TLR agonists induced similar levels of NF-kappaB and AP-1 DNA-binding activity, as well as trans-activation function. Unexpectedly, these TLR agonists induced tumor necrosis factor alpha secretion, whereas only LPS was capable of inducing interleukin-1beta and nitric oxide secretion. Thus, different TLR proteins are still capable of activating distinct cellular responses, in spite of their shared capacities to activate NF-kappaB, AP-1, and MAP kinases.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • CHO Cells
  • Cricetinae
  • Cricetulus
  • Drosophila Proteins*
  • Enzyme Activation / drug effects
  • Enzyme Induction / drug effects
  • Gene Expression Regulation / drug effects
  • Interleukin-1 / biosynthesis
  • Interleukin-1 / genetics
  • Lipopolysaccharides / pharmacology*
  • MAP Kinase Signaling System / drug effects
  • Macrophage Activation / drug effects*
  • Macrophages / drug effects*
  • Membrane Glycoproteins / agonists*
  • Mice
  • Mycobacterium tuberculosis / chemistry
  • NF-kappa B / metabolism
  • Nitric Oxide / biosynthesis
  • Nitric Oxide / metabolism
  • Nitric Oxide Synthase / genetics
  • Nitric Oxide Synthase / metabolism
  • Nitric Oxide Synthase Type II
  • Phosphatidylinositols / isolation & purification
  • Phosphatidylinositols / pharmacology*
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Receptors, Cell Surface / agonists*
  • Recombinant Fusion Proteins / physiology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / drug effects*
  • Toll-Like Receptor 2
  • Toll-Like Receptor 4
  • Toll-Like Receptors
  • Transcription Factor AP-1 / metabolism
  • Transfection
  • Tumor Necrosis Factor-alpha / biosynthesis
  • Tumor Necrosis Factor-alpha / genetics

Substances

  • Drosophila Proteins
  • Interleukin-1
  • Lipopolysaccharides
  • Membrane Glycoproteins
  • NF-kappa B
  • Phosphatidylinositols
  • RNA, Messenger
  • Receptors, Cell Surface
  • Recombinant Fusion Proteins
  • Toll-Like Receptor 2
  • Toll-Like Receptor 4
  • Toll-Like Receptors
  • Transcription Factor AP-1
  • Tumor Necrosis Factor-alpha
  • lipoarabinomannan
  • phosphatidylinositol dimannoside
  • phosphatidylinositol mannoside
  • Nitric Oxide
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type II
  • Nos2 protein, mouse