Extracellular vesicles with ubiquitinated adenosine A _2A receptor in plasma of patients with coronary artery disease

Abstract

Extracellular vesicles (EV) can transfer cellular molecules for specific intercellular communication with potential relevance in pathological conditions. We searched for the presence in plasma from coronary artery disease (CAD) patients of EV containing the adenosine A _2A receptor (A _2AR), a signalling receptor associated with myocardial ischaemia and whose expression is related to homocysteine (HCy) metabolism. Using protein organic solvent precipitation for plasma EV preparation and Western blotting for protein identification, we found that plasma from CAD patients contained various amounts of EV with ubiquitin bound to A _2AR. Interestingly, the presence of ubiquitinated A _2AR in EV from patients was dependent on hyperhomocysteinemia, the amount being inversely proportional to A _2AR expression in peripheral mononuclear cells in patients with the highest levels of HCy. CEM, a human T cell line, was also found to released EV containing various amounts of ubiquitinated A _2AR in stimulated conditions depending on the hypoxic status and HCy level of culture medium. Together, these data show that ubiquitinated A _2AR‐containing EV circulate in the plasma of CAD patients and that this presence is related to hyperhomocysteinemia. A _2AR in plasma EV could be a useful tool for diagnosis and a promising drug for the treatment of CAD.