Human trophoblast-derived exosomal fibronectin induces pro-inflammatory IL-1β production by macrophages

Am J Reprod Immunol. 2011 Oct;66(4):259-69. doi: 10.1111/j.1600-0897.2011.00995.x. Epub 2011 Mar 17.


PROBLEM Our previous studies demonstrated that trophoblast-derived exosomes induced synthesis and release of pro-inflammatory cytokines, including interleukin-1β (IL-1β) by macrophages. The objective of this study was to characterize the mechanism and receptors associated with this induction. METHOD OF STUDY Exosomes were isolated from Sw71 trophoblast-conditioned media by ultrafiltration and ultracentrifugation. Using macrophages isolated from normal donors, cytochalasin D was used to block exosome uptake. Induction of IL-1β mRNA was investigated by qRT-PCR, pro-IL-1β protein by western immunoblotting, and mature IL-1β release by ELISA. RGD peptides were used to block fibronectin binding by macrophage α5β1 integrin. RESULTS Uptake of exosomes by macrophages was completely blocked by pre-treatment with cytochalasin D. Although induction of some cytokines (such as C4A and CCL11) requires uptake, induction of IL-1β occurred without exosome internalization. Cytochalasin D treatment did not inhibit exosome-mediated induction of IL-1β mRNA, production of the pro-protein, or release of mature IL-1β. Blocking of fibronectin binding using RGD peptides demonstrated the abrogation of exosome-mediated IL-1β production. CONCLUSION Although trophoblast-derived exosomes have been demonstrated to induce IL-1β, this is the first demonstration of IL-1β induction by exosome-associated fibronectin. Based on this pro-inflammatory role of exosome-associated fibronectin, it may represent an important general immunoregulatory mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Chemokine CCL11 / biosynthesis
  • Culture Media, Conditioned / chemistry
  • Cytochalasin D / pharmacology
  • Endocytosis / drug effects*
  • Endocytosis / immunology
  • Enzyme-Linked Immunosorbent Assay
  • Exosomes / immunology
  • Exosomes / metabolism*
  • Female
  • Fibronectins / immunology
  • Fibronectins / metabolism*
  • Humans
  • Inflammation / immunology
  • Inflammation / metabolism
  • Interleukin-1beta / analysis
  • Interleukin-1beta / biosynthesis*
  • Macrophage Activation / drug effects
  • Macrophages / drug effects
  • Macrophages / immunology
  • Macrophages / metabolism*
  • Oligopeptides / pharmacology
  • Pregnancy
  • Protein Binding / drug effects
  • RNA, Messenger / analysis
  • RNA, Messenger / biosynthesis
  • Real-Time Polymerase Chain Reaction
  • Receptors, Immunologic / antagonists & inhibitors
  • Receptors, Peptide / antagonists & inhibitors
  • Trophoblasts / cytology
  • Trophoblasts / immunology
  • Trophoblasts / metabolism*
  • Ultracentrifugation


  • Chemokine CCL11
  • Culture Media, Conditioned
  • Fibronectins
  • Interleukin-1beta
  • Oligopeptides
  • RNA, Messenger
  • Receptors, Immunologic
  • Receptors, Peptide
  • arginyl-glycyl-aspartic acid directed cell adhesion receptor
  • Cytochalasin D
  • arginyl-glycyl-aspartic acid