Decreased CD39 expression is associated with increased PMN adhesion to posthypoxic endothelia in vitro and in vivo. (A) HMEC-1 cells were loaded with CD39-specific siRNA, control ribonucleotide, mock-treated (control) or lamin A/C (Lmn C) siRNA controls and exposed to normoxia (N) or hypoxia (H; 2% normobaric oxygen for 48 h). Monolayers were washed, surface proteins were biotinylated, and cells were lysed. CD39 was immunoprecipitated and resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and resultant Western blots were probed with avidin-peroxidase. (B) HMEC-1s were loaded with specific CD39 siRNA, a nonspecific control siRNA, mock-treated (control), or lamin A/C siRNA and exposed to hypoxia or normoxia (48 h). BCECF-labeled FMLP-activated PMNs were added (105 PMNs per condition) and PMN adhesion was quantified by measuring fluorescence (*P < .05 compared with normoxic control and to normoxia; #P < .05 compared with normoxia). (C) cd39-null (▪) or wild-type littermate (□) mice were subjected to either normoxia (room air) or normobaric hypoxia (8% O2 and 92% N2) for 4 hours, and the indicated organs (colon, Co; lung, Lu; liver, Li; or kidney, Ki) were assessed for PMN accumulation by measuring myeloperoxidase activity (*P < .025 compared with normoxia; #P < .025 compared with wild-type). Data are presented as mean ± SEM.
