Expression of a short antibody heavy chain peptide effectively antagonizes adenosine 2A receptor in vitro and in vivo

Adenosine 2A receptor (A2AR) is involved in many physiological and pathological functions and serves as an important drug target. Inhibition of A2AR may alleviate symptoms associated with a variety of neuropsychiatric disorders. However, the currently used A2AR antagonists have specificity limitations.
A Fab fragment (Fab2838) of an A2AR mouse monoclonal antibody can specifically bind to A2AR to form a complex and inhibit the activity of its receptor. We constructed the vector AntiA2AR, a small-molecule peptide that binds to and inhibits A2AR based on Fab2838.
Experiments in HEK293T cells showed that peptide AntiA2AR of 29 peptides was the most effective among the synthesized peptides in inhibiting the A2AR downstream signal cAMP/PKA/CREB. In neurons, the AntiA2AR reversed the calcium flow change induced by the A2AR agonist CGS21680 (1 μM). Furthermore, AntiA2AR expression in the mice striatum weakened the p-PKA/p-CREB signal, enhanced locomotor abilities and increased time spent in the center area in the home-cage observation experiment and increased anxiolytic behavior in the elevated-plus maze test.
Antagonistic peptide AntiA2AR can effectively block the A2AR signaling pathway. This provides a new strategy for the specific inhibition of A2AR and provides information needed for drug development.