Introduction: β1 Integrins bind to the basement membrane components; fibronectin, laminin and collagen. Binding of β1 integrins is dependent on the molecule attaining its active confirmation. Deglycosylation of β1 integrins on epithelial cells is known to decrease cell adhesion to fibronectin. The role of glycosylation in the adhesion of β1 integrins on granulocytes has not been studied. Methods: HL-60 cells were treated with neuraminidase or neuraminidase and β galactosidase to evaluate the effect of glycosylation on adhesion. HL-60 cells were labeled with the fluorescent probe Calcein-AM (Molecular Probes). Percent adhesion was determined by comparison of the bound and unbound fractions following a 15 minute incubation period in fibronectin coated wells. Binding of activated β1 integrins is measured by the same procedure with the addition of PMA to the adhesion well. Flow cytometric analysis was used to evaluate total and activated β1 integrin populations in glycosidase treated stimulated and unstimulated cells. Results: In control and PMA stimulated cells baseline and activated adhesion increased in the glycosidase treated groups. Baseline adhesion increased from 18.8% to 34.4% in neuraminidase treated cells and to 39.6 % in neuraminidase and β galactosidase treated cells. In PMA stimulated cells adhesion increased from 58.8 % in control cells to 74.2% in neuraminidase treated cells and to 71.4% in neuraminidase and β-galactosidase treated cells. Flow cytometric data show increased activated β1 integrin in glycosidase treated cells in both stimulated and unstimulated cells. Conclusions: Deglycosylation of β1 integrins in a granulocyte model increases cell adhesion to fibronectin in both stimulated and unstimulated cells. This is in contrast to a decrease in cell adhesion in deglycosylated epithelial cells. We speculate that the glycosylation of β1 integrins on granulocytes serves a receptor blocking function as opposed to its proadhesive properties on epithelial cells.
|Original language||English (US)|
|Journal||Critical Care Medicine|
|Issue number||1 SUPPL.|
|State||Published - 1999|
ASJC Scopus subject areas
- Critical Care and Intensive Care Medicine