Macrophage migration inhibitory factor and CD74 regulate macrophage chemotactic responses via MAPK and Rho GTPase

J Immunol. 2011 Apr 15;186(8):4915-24. doi: 10.4049/jimmunol.1003713. Epub 2011 Mar 16.

Abstract

Macrophage migration inhibitory factor (MIF) promotes leukocyte recruitment to sites of inflammation. However, whether this stems from a direct effect on leukocyte migration is unknown. Furthermore, the role of the MIF-binding protein CD74 in this response has not been investigated. Therefore, the aim of this study was to examine the contributions of MIF and CD74 to chemokine-induced macrophage recruitment. Intravital microscopy studies demonstrated that CCL2-induced leukocyte adhesion and transmigration were reduced in MIF(-/-) and CD74(-/-) mice. MIF(-/-) and CD74(-/-) macrophages also exhibited reduced chemotaxis in vitro, although CD74(-/-) macrophages showed increased chemokinesis. Reduced CCL2-induced migration was associated with attenuated MAPK phosphorylation, RhoA GTPase activity, and actin polymerization in MIF(-/-) and CD74(-/-) macrophages. Furthermore, in MIF(-/-) macrophages, MAPK phosphatase-1 was expressed at elevated levels, providing a potential mechanism for the reduction in MAPK phosphorylation in MIF-deficient cells. No increase in MAPK phosphatase-1 expression was observed in CD74(-/-) macrophages. In in vivo experiments assessing the link between MIF and CD74, combined administration of MIF and CCL2 increased leukocyte adhesion in both MIF(-/-) and CD74(-/-) mice, showing that CD74 was not required for this MIF-induced response. Additionally, although leukocyte recruitment induced by administration of MIF alone was reduced in CD74(-/-) mice, consistent with a role for CD74 in leukocyte recruitment induced by MIF, MIF-treated CD74(-/-) mice displayed residual leukocyte recruitment. These data demonstrate that MIF and CD74 play previously unappreciated roles in CCL2-induced macrophage adhesion and migration, and they indicate that MIF and CD74 mediate this effect via both common and independent mechanisms.

Publication types

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

MeSH terms

  • Animals
  • Antigens, Differentiation, B-Lymphocyte / genetics
  • Antigens, Differentiation, B-Lymphocyte / metabolism*
  • Blotting, Western
  • Cell Adhesion / drug effects
  • Cell Adhesion Molecules / metabolism
  • Cell Movement / drug effects
  • Cells, Cultured
  • Chemokine CCL2 / pharmacology
  • Chemokines / metabolism
  • Chemotaxis, Leukocyte / drug effects
  • Dual Specificity Phosphatase 1 / genetics
  • Dual Specificity Phosphatase 1 / metabolism*
  • Histocompatibility Antigens Class II / genetics
  • Histocompatibility Antigens Class II / metabolism*
  • Leukocytes / drug effects
  • Leukocytes / metabolism
  • Macrophage Migration-Inhibitory Factors / genetics
  • Macrophage Migration-Inhibitory Factors / metabolism*
  • Macrophages / cytology
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Phosphorylation / drug effects
  • Reverse Transcriptase Polymerase Chain Reaction
  • rho GTP-Binding Proteins / metabolism*

Substances

  • Antigens, Differentiation, B-Lymphocyte
  • Cell Adhesion Molecules
  • Chemokine CCL2
  • Chemokines
  • Histocompatibility Antigens Class II
  • Macrophage Migration-Inhibitory Factors
  • invariant chain
  • Dual Specificity Phosphatase 1
  • rho GTP-Binding Proteins