Membrane-type 1-Matrix Metalloproteinase Regulates Intracellular Adhesion Molecule-1 (ICAM-1)-mediated Monocyte Transmigration

Andrew H Baker,William R English,Davia Krubasik,Srinivas D Sithu,Gillian Murphy,Paul Olson,Stanley E D'Souza

doi:10.1074/jbc.m611273200

Abstract

We examined the mechanism regulating intercellular cell adhesion molecule-1 (ICAM-1)-dependent monocyte transendothelial migration. Monocyte migration through endothelial cells expressing ICAM-1 alone was comparable to that of tumor necrosis factor-alpha-treated cells. Transmigration was reduced in ICAM-1 lacking the cytoplasmic tail and in tyrosine to alanine substitutions at Tyr-485 and Tyr-474. Tissue inhibitors of matrix metalloproteinases (TIMPs) -2 and -3 blocked transmigration, whereas TIMP-1 was ineffective. This profile suggested a role for membrane-type matrix metalloproteinases (MT-MMPs) in transmigration. Inhibitory antibodies and small interference RNA directed against MT1-MMP blocked transmigration, whereas overexpression of MT1-MMP in endothelial cells or monocytes promoted transmigration. MT1-MMP mediated the ectodomain cleavage of ICAM-1 that was blocked by TIMP-2 and -3. Overexpression of MT1-MMP rescued function in ICAM-1Y485A, and to a lesser extent in the cytoplasmic tail-deleted ICAM-1. In a binding assay, wild-type ICAM-1 bound to purified MT1-MMP while ICAM-1 mutants bound poorly. MT1-MMP co-localized with ICAM-1 at distinct structures in endothelial cells. MT1-MMP localization with cells expressing ICAM-1 mutations was reduced and diffused. These results indicate that the cytoplasmic tail of ICAM-1 regulates leukocyte transmigration through MT1-MMP interaction.

Highlights

To examine the capacity of the transfected intercellular cell adhesion molecule-1 (ICAM-1)-expressing endothelial cells (ECs) (ECICAM-1) to regulate monocyte TM, the cells were grown on Transwells for 2 days to develop a monolayer and secrete extracellular matrix proteins
An average of 6.6 ϫ 104 monocytes transmigrated through ECICAM-1, whereas only 1.5 ϫ 104 monocytes migrated through ECs not expressing ICAM-1 (Fig. 1B)
ICAM-1-dependent monocyte TM levels were close to that achieved with TNF-␣ stimulated ECs (Fig. 1A)

Summary

Introduction

To examine the capacity of the transfected ICAM-1-expressing ECs (ECICAM-1) to regulate monocyte TM, the cells were grown on Transwells for 2 days to develop a monolayer and secrete extracellular matrix proteins. Inhibitors of MPs (TNF-␣ protease become phosphorylated and regulate ICAM-1 function [6, 7], inhibitor-1 and MMP inhibitor-III) blocked ICAM-1-dependwe examined whether deletion of the cytoplasmic tail and tyro- ent monocyte TM (Fig. 3A). The transmigration of TIMP-2 and -3 overexpressing monocytic cells was inhibited, to a lesser degree than when TIMP-2 and -3 were expressed in ECs alone (Fig. 3E).

Results

Conclusion