Reactive oxygen species regulate hemocyte migration in abalone (Haliotis diversicolor)

Hemocyte migration in invertebrates has been known to be involved into several important physiological functions such as phagocytosis and wound healing. In addition to chemotaxis or haptotaxis, the other regulatory mechanisms on the cell migration still need to be unraveled. In recent studies, reactive oxygen species (ROS) is not only generally considered as threat for cells, but also found as important modulators for some cell behaviors. In mammals, ROS can activate migration in different types of cells including neurons, endothelial cells, and cancer cells. ROS also serves as chemoattractant and stimulator for leukocytes in zebra fish. Therefore, we proposed that ROS may also play crucial roles in invertebrate hemocyte migration. In this study, both cell mobility and ROS production of two types of hemocyte in abalone (Haliotis diversicolor) were recorded by live time lapse microscopy. On the other hand, when the hemocytes were treated with 5 μM diphenyleneiodonium chloride (DPI), which is a NADPH oxidase inhibitor and can decreases cellular ROS accumulation, for one hour and then cultured additional 16 hours in the medium, the spread of cell sheet was significantly inhibited compared to the control group of cells. And the DPI‐treated cell mobility reduced from 42 μm / hour to 32 μm / hour. These results strongly suggested that ROS can mediate the hemocyte migration.