Membrane Cholesterol Is A Biomechanical Regulator Of Neutrophil Adhesion

Objective-The purpose of this study was to evaluate the role of membrane cholesterol on human neutrophil and HL-60 biomechanics, capture, rolling, and arrest to P-selectin- or IL-1-activated endothelium.Methods and Results-Methyl-beta-cyclodextrin (M beta CD) removed up to 73% and 45% of membrane cholesterol from HL-60 cells and neutrophils, whereas M beta CD/cholesterol complexes resulted in maximum enrichment of 65% and 40%, respectively, above control levels. Cells were perfused at a venous wall shear rate of 100 s(-1) over adherent P-selectin- coated 1-mu m diameter beads, uncoated 10-mu m diameter beads, P-selectin- coated surfaces, or activated endothelium. Elevated cholesterol enhanced capture efficiency to 1-mu m beads and increased membrane tether growth rate by 1.5- to 2-fold, whereas cholesterol depletion greatly reduced tether formation. Elevated cholesterol levels increased tether lifetime by 17% in neutrophils and adhesion lifetime by 63% in HL-60 cells. Deformation of cholesterol-enriched neutrophils increased the contact time with 10-mu m beads by 32% and the contact area by 7-fold. On both P-selectin surfaces and endothelial- cell monolayers, cholesterol-enriched neutrophils rolled more slowly, more stably, and were more likely to firmly arrest. Cholesterol depletion resulted in opposite effects.Conclusions-Increasing membrane cholesterol enhanced membrane tether formation and whole cell deformability, contributing to slower, more stable rolling on P-selectin and increased firm arrest on activated endothelium. (Arterioscler Thromb Vasc Biol. 2009;29:1290-1297.)