Study on the relation among protein kinase C activity,adhesion molecules expression of irradiated vascular endothelial cells and transmigration of haemopoietic stem cells

Objective To study the relation among protein kinase C (PKC),adhesion molecules expression of vascular endothelial cells irradiated by small dose of γ-rays and transmigration of haemopoietic stem cells. Methods Human umbilical vein endothelial cells (HUVECs) were irradiated with 1-5 Gy γ-rays.The PKC activity of irradiated cells was measured by the incorporation of [γ- 32P] ATP into exogenous substrate.The expression of adhesion molecules VCAM-1,PECAM-1, CD44 in irradiated HUVECs was detected by ELISA and transmigration of CD34++ haemopoietic stem cells across the irradiated HUVECs was determined by the transwell migration assay. Results PKC in HUVECs was activated by less than 3 Gy γ-irradiation,resulting in membranous PKC activity increasing and cytosolic PKC activity decreasing gradually.The dominant change occurred in HUVECs irradiated by 2_3 Gy γ-rays (P0.01).There was a decreasing trend of membranous and cytosolic activity PKC in HUVECs irradiated by more than 3 Gy γ-rays.The expressions of VACM_1,PECAM_1 and CD44 in HUVECs irradiated by less than 3 Gy γ-rays were significantly increased compared with the results of the control group(P0.01).The numbers of CD34++ haemopoietic stem cells migrating across the irradiated HUVECs were much higher than those in the control group (P0^01),but monoclonal antibodies to VACM_1,PEACM_1,CD44 could depress the transmigration activity.There was a positive relation beween the PKC activity and the expression of VCAM_1,PECAM_1 and CD44 respectively. Conclusions Optimal small dose of γ-rays could activate PKC,enhance PKC activity of irradiated vascular endothelial cells,and up-regulate the adhesion molecules expression of VACM_1,PECAM_1 and CD44,resulting in promoting the transendothelial migration of haemopoietic stem cells.