摘要
P-selectin engagement of P-selectin glycoprotein Iigand-1 （PSGL-1） causes circulating leukocytes to roll on and adhere to the vascular surface, and mediates intracellular calcium flux, a key but unclear event for subsequent arresting firmly at and migrating into the infection or injured tissue. Using a parallel plate flow chamber technique and intracellular calcium ion detector （Fluo-4 AM）, the intracellular calcium flux of firmly adhered neutrophils on immobilized P-selectin in the absence of chemokines at various wall shear stresses was investigated here in real time by fluorescence microscopy. The results demon- strated that P-selectin engagement of PSGL-1 induced the intracellular calcium flux of firmly adhered neutrophils in flow, increasing P-selectin concentration enhanced cellu- lar calcium signaling, and, force triggered, enhanced and quickened the cytoplasmic calcium bursting of neu- trophils on immobilized P-selectin. This P-selectin-induced calcium signaling should come from intracellular calcium release rather than extracellular calcium influx, and be along the mechano-chemical signal pathway involving the cytoskeleton, moesin and Spleen tyrosine kinase （Syk）. These results provide a novel insight into the mechano-chemical regulation mechanism for P-selectininduced calcium signaling of neutrophils in flow.
P-selectin engagement of P-selectin glycoprotein Iigand-1 （PSGL-1） causes circulating leukocytes to roll on and adhere to the vascular surface, and mediates intracellular calcium flux, a key but unclear event for subsequent arresting firmly at and migrating into the infection or injured tissue. Using a parallel plate flow chamber technique and intracellular calcium ion detector （Fluo-4 AM）, the intracellular calcium flux of firmly adhered neutrophils on immobilized P-selectin in the absence of chemokines at various wall shear stresses was investigated here in real time by fluorescence microscopy. The results demon- strated that P-selectin engagement of PSGL-1 induced the intracellular calcium flux of firmly adhered neutrophils in flow, increasing P-selectin concentration enhanced cellu- lar calcium signaling, and, force triggered, enhanced and quickened the cytoplasmic calcium bursting of neu- trophils on immobilized P-selectin. This P-selectin-induced calcium signaling should come from intracellular calcium release rather than extracellular calcium influx, and be along the mechano-chemical signal pathway involving the cytoskeleton, moesin and Spleen tyrosine kinase （Syk）. These results provide a novel insight into the mechano-chemical regulation mechanism for P-selectininduced calcium signaling of neutrophils in flow.
基金
ACKNOWLEDGEMENTS This work was supported by the National Natural Science Foundation of China [Grant Nos. 11432006 （JW）, 31170887 （JW） and 11272125 （YF）] and by the Fundamental Research Funds for the Central Universities （SCUT） （JW）.
