作者：Xiaoxi; Sun; Yuping; Pan; Ying; Fang; ...integrinactivationinteractioncellularcalciumburstingcoupling
摘要：Inflammation and thrombosis usually occur together in many diseases,such as cardiovascular disease(CVD)and stroke,which remain to be the mostdetrimental human health killers.The crucial relevant cellular and molecular events include platelet-leukocyte interaction,platelet P-selectin secretion of activated platelet and activation of leukocyte integrin Mac-1(also known asαMβ2 or CD11b/CD18),which has binding site of platelet receptor glycoprotein lbα(GPlboα). Circulating leukocytes tethered to,rolled on and firmly adhered at the activated platelets on vascular wall,through interaction of platelet P-selectin with leukocyte P-selectin glycoprotein ligand-1(PSGL-1)and Mac-1 with GPlbα.We assume that there is a rapid signaling pathway in PSGL-1 ligation-induced activation of Mac-1,for forming a stable gap junction intracellular communication between platelet and leukocyte.To test this assumption,we observed the tethering events and calcium bursting of neutrophils on immobilized P-selectin only or plus GPlbαwith use of the parallel plate flow chamber(PPFC)technique and intracellular calcium ion detector Fluo-4 AM at various wall shear stresses,and examined the dynamic force spectrum for interaction of Mac-1 plus Mn2+and GPlbαby single-molecule atomic force microscopy(AFM).In the PPFC experiments,the intracellular calcium flux of firmly adhered neutrophils on immobilized P-selectin only or plus GPlbαwas observed in real timeby fluorescence microscopy,and the tether events of neutrophils was recorded by an inverted microscope and a high speed CMOS acquisition system in 1280 pixels×1024 pixels at 100 frames per second(fps). Captured images were analyzed by Image Pro Plus.Our results indicated that force triggered,enhanced and quickened the cytoplasmic calcium bursting of neutrophils.Calcium bursting may be induced first by interaction of the activated neutrophil Integrin Mac-1 and GPlbα,but not by P-selectin ligation to its ligand PSGL-1.Being triggered and speeded up by wall shear stress,the P-selectin-induced a
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