title: Impact of carrier stiffness and microtopology on two-dimensional kinetics of P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1) interactions.
abstract: Mechanics and surface microtopology of the molecular carrier influence cell adhesion, but the mechanisms underlying these effects are not well understood. We used a micropipette adhesion frequency assay to quantify how the carrier stiffness and microtopology affected two-dimensional kinetics of interacting adhesion molecules on two apposing surfaces. Interactions of P-selectin with P-selectin glycoprotein ligand-1 (PSGL-1) were used to demonstrate such effects by presenting the molecules on three carrier systems: human red blood cells (RBCs), human promyelocytic leukemia HL-60 cells, and polystyrene beads. Stiffening the carrier alone or in cooperation with roughing the surface lowered the two-dimensional affinity of interacting molecules by reducing the forward rate but not the reverse rate, whereas softening the carrier and roughing the surface had opposing effects in affecting two-dimensional kinetics. In contrast, the soluble antibody bound with similar three-dimensional affinity to surface-anchored P-selectin or PSGL-1 constructs regardless of carrier stiffness and microtopology. These results demonstrate that the carrier stiffness and microtopology of a receptor influences its rate of encountering and binding a surface ligand but does not subsequently affect the stability of binding. This provides new insights into understanding the rolling and tethering mechanism of leukocytes onto endothelium in both physiological and pathological processes.
authors.affiliation: National Microgravity Laboratory and Center for Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wu
authors.affiliation: National Microgravity Laboratory and Center for Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Botao
authors.initials: B
authors.lastname: Xiao
authors.affiliation: National Microgravity Laboratory and Center for Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Jia
authors.affiliation: National Microgravity Laboratory and Center for Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: National Microgravity Laboratory and Center for Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Shouqin
authors.initials: S
authors.lastname: Lü
authors.affiliation: National Microgravity Laboratory and Center for Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.affiliation: National Microgravity Laboratory and Center for Biomechanics and Bioengineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China. Electronic address: mlong@imech.ac.cn.
authors.forename: Mian
authors.initials: M
authors.lastname: Long
mesh_terms: D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D018922:HL-60 Cells; D006801:Humans; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D019007:P-Selectin / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D025941:Protein Interaction Mapping; D021381:Protein Transport / Q000502:physiology
chemical_list: D008562:Membrane Glycoproteins; D019007:P-Selectin; C084882:P-selectin ligand protein