Abstract
The effect of etxtracellular ATP on cell migration was investigated using 3T3-L1 cell line. In control preadipocytes, staining of actin filaments with phalloidin revealed a network of actin stress fibers running through the cytoplasm constructing a cellular frame as is typically observed in fibroblasts. After the cells were incubated with 10 μM ATP for 5 min at 37oC, actin filament structures underwent a significant change in distribution mediated through P2Y receptors, forming a peripheral meshwork of broad, sheet-like structure (lamellipodia) and surface projections of thin, needle-like structures (filopodia), generally found at the plasma membrane of migrating cells. We then examined whether purinergic stimulation enhances the migration of the cells using chemotaxis assay chamber or chemokinesis assay filter system. Preadipocytes were found to migrate towards the source of ATP (chemotaxis) with the maximal migration of 80 μm within 60 min at 37oC. Random cell migration (chemokinesis) was also observed with a smaller magnitude. In contrast, mature adipocytes tightly adhered to the extracellular matrix and appeared to be almost immobilized during the incubation. These results indicate that the extracellular ATP acts as a chemoattractant for preadipocytes, but not for mature adipocytes. [J Physiol Sci. 2007;57 Suppl:S86]
