Hypoxia regulates osteopontin expression of mature dendritic cells via adenosine 2 receptor
Objective To investigate the mechanism of hypoxia regulate osteopontin (OPN) secreting by mature dendritic cells (mDCs). Methods CD14 + cells were enriched using anti-CD14 immunomagnetic beads, for inducing to mDCs, CD14 + cells were cultured with GM-CSF and IL-4 in hypoxia or normoxiain vitro. Concentration of OPN and TGF-β1 in supernatant were detected by sandwich ELISA, OPN mRNA detected by RT-PCR. Approach regulating function of A2 R in expressing of OPN by mDCs by using NECA (surrogate of adenosine), A2R agonist (CGS21680), A2R antagonist (SCH58261) and investigate role of TGF-β1 in this process by using rhTGF-β1 and anti-TGF-β1 Ab. Results Hypoxia inreased the level of OPN and OPN mRNA in mDCs, and this effect could be reversed by A2 R antagonist. Under normoxia,both NECA and A2R agonist (CGS21680) could upregulate the level of OPN and OPN mRNA in mDCs significantly, but this positive effect could be reversed by A2 R antagonist. A2 R played a role in regulating TGF-β1, and confirmed TGF-β1 involved in regulation of OPN by using rhTGF-β1 and anti-TGF-β1 Ab. Conclusion High adenosine induce the generation of TGF-β1 through the A2R on mDCs, and then TGF-β1 raise the OPN secreting by mDCs. 
 
Key words: 
Mature dendritic cells;  Adenosine A2 receptor;  Osteopontin;  Hypoxia