Adenosine A2A agonists in development for the treatment of inflammation

Extracellular adenosine binds specifically to a family of four G protein-coupled cell-surface adenosine receptors (ARs). As the activation of the A(2A)AR modulates the activity of multiple inflammatory cells including neutrophils, macrophages and T lymphocytes, the receptor is considered to be a promising pharmacological target for the treatment of inflammatory disorders. Although adenosine binds nonselectively to all four AR subtypes, A(2A)AR selective agonists have been developed and shown to inhibit multiple manifestations of inflammatory cell activation including superoxide anion generation, cytokine production and adhesion molecule expression. A(2A)AR agonists are also vasodilators, but the inhibition of inflammation occurs at low doses that produce few or no cardiovascular side effects. Therefore, the selective activation of the A(2A)AR by these compounds holds significant potential in the treatment of inflammation.