beta(2)-Integrin blockade driven by E-selectin promoter prevents neutrophil sequestration and lung injury in mice

Interaction of CD11/CD18 beta(2) integrins on polymorphonuclear leukocytes (PMNs) with their counterreceptor, intercellular adhesion molecule-1, on th e surface of vascular endothelial cells is a critical event mediating stabl e PMN adhesion and mi,oration across the pulmonary vascular endothelial bar rier. Neutrophil inhibitory factor (NIF), a 41-kDa glycoprotein isolated fr om the canine hookworm (Ancylostoma caninum), binds to the I domain of CD11 a and CD11b and inhibits beta(2) integrin-dependent PMN adhesion. We descri be a novel strategy using the endothelial cell-specific E-selectin promoter to induce NIF expression in an inflammation-specific manner in pulmonary v ascular endothelial cells. A construct containing NIF cDNA driven by the in ducible endothelial cell-specific E-selectin promoter (pESNIF) was transfec ted into human pulmonary artery endothelial cells (HPAECs). Lipopolysacchar ide challenge (known to activate E-selectin) resulted in NIF mRNA and prote in expression in transfected HPAECs. NIF expression induced by the E-select in promoter prevented PMN adhesion to the activated HPAECs, whereas PMNs ad hered avidly to activated HPAECs in the absence of NIF expression To addres s the utility of this approach in conditionally preventing in vivo PMN sequ estration, we injected mice intravenously with cationic liposomes containin g the pESNIF construct. Analysis of lung tissue showed that intraperitoneal challenge of Escherichia call resulted in NIF expression. Inflammation-spe cific NIF expression induced by the E-selectin promoter prevented lung PMN sequestration and vascular injury induced by E coli challenge. These studie s suggest the feasibility of conditionally blocking beta(2) integrin functi on at sites where the endothelium is activated and thereby of locally preve nting PMN activation and migration responses that lead to tissue inflammati on.