Oxidized low-density lipoproteins enhance expression and activity of CD39 and CD73 in the human aortic valve endothelium.

Extracellular nucleotides regulate thrombosis, inflammation and immune response. Ectonucleoside triphosphate diphosphohydrolase 1 (CD39) and ecto-5'-nucleotidase (CD73) convert extracellular nucleotides in a sequential order: ATP to ADP, AMP and then to adenosine. In this study, we aimed to test an effect of oxidized LDL (ox-LDL) on CD39 and CD73 in endothelial cells. Human aortic valve endothelial cells were exposed to oxidized low-density lipoprotein, for 24-48 h. Next, the activity, protein expression and mRNA transcripts level of CD39 and CD73 were characterised by: an incubation with ATP or AMP followed by HPLC analysis of media as well as western blots and qPCR. Results are presented as mean ± SEM. CD73 activity in human valve endothelial cells was increased in presence of ox-LDL (4.04±0.32 nmol/mg prot./min) as compared to control (2.75±0.21 nmol/mg prot/min). There was almost no effect of ox-LDL on CD39 activity. A similar effect was observed for mRNA and protein expression. In conclusion, we found that ox-LDL modulated CD39 and CD73 activity in the endothelium, which may contribute to relevant pathologies and featured treatments