Non-adsorbing macromolecules promote endothelial adhesion of erythrocytes with reduced sialic acids

• Published in: Biochimica et biophysica acta Vol. 1840; no. 1; pp. 288 - 293
• Main Authors: Yang, Yang, Koo, Stephanie, Heng, Li Tze, Meiselman, Herbert J., Neu, Björn
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2014
• Subjects: adhesion; blood proteins; Cell Adhesion - physiology; Cell Membrane - metabolism; Cells, Cultured; Dextran; Dextrans - metabolism; diabetes; endothelium; erythrocytes; Erythrocytes - cytology; Erythrocytes - metabolism; human umbilical vein endothelial cells; Human Umbilical Vein Endothelial Cells - cytology; Human Umbilical Vein Endothelial Cells - metabolism; Humans; Macromolecular depletion interaction; membrane potential; membrane proteins; molecular weight; Neuraminidase; Neuraminidase - metabolism; Red blood cell adhesion; Sialic acids; Sialic Acids - metabolism; sialidase; sickle cell anemia; synergism; zeta potential; Dextran; Red blood cell adhesion; Macromolecular depletion interaction; Sialic acids; Neuraminidase
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2013.09.031

Abnormal adhesion of red blood cells (RBCs) to vascular endothelium is often associated with reduced levels of sialic acids on RBC membranes and with elevated levels of pro-adhesive plasma proteins. However, the synergistic effects of these two factors on the adhesion are not clear. In this work, we tested the hypothesis that macromolecular depletion interaction originating from non-adsorbing macromolecules can promote the adhesion of RBCs with reduced sialic acid content to the endothelium. RBCs are treated with neuraminidase to specifically remove sialic acids from their surface followed by the evaluation of their deformability, zeta potential and membrane proteins. The adhesion of these enzyme-treated RBCs to cultured human umbilical vein endothelial cells (ECs) is studied in the presence of 70 or 500kDa dextran with a flow chamber assay. Our results demonstrate that removal of sialic acids from RBC surface can induce erythrocyte adhesion to endothelial cells and that such adhesion is significantly enhanced in the presence of high-molecular weight dextran. The adhesion-promoting effect of dextran exhibits a strong dependence on dextran concentration and molecular mass, and it is concluded to originate from macromolecular depletion interaction. These results suggest that elevated levels of non-adsorbing macromolecules in plasma might play a significant role in promoting endothelial adhesion of erythrocytes with reduced sialic acids. Our findings should therefore be of great value in understanding abnormal RBC–EC interactions in pathophysiological conditions (e.g., sickle cell disease and diabetes) and after blood transfusions. [Display omitted] •Removal of sialic acid from the erythrocyte surface induces erythrocyte adhesion.•Depletion forces enhance adhesion of blood cells with reduced sialic acid content.•This mechanism explains abnormal cell interactions in pathophysiological conditions.