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

A note on partial calmness for bilevel optimization problems with linearly structured lower level

Partial calmness is a celebrated but restrictive property of bilevel optimization problems whose presence opens a way to the derivation of Karush–Kuhn–Tucker-type necessary optimality conditions in order to characterize local minimizers. In the past, sufficient conditions for the validity of partial calmness have been investigated. In this regard, the presence of a linearly structured lower level problem has turned out to be beneficial. However, the associated literature suffers from inaccurate results. In this note, we clarify some regarding erroneous statements and visualize the underlying issues with the aid of illustrative counterexamples.</p