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

Background: Adenosine 2A receptor (AR) is involved in many physiological and pathological functions and serves as an important drug target. Inhibition of AR may alleviate symptoms associated with a variety of neuropsychiatric disorders. However, the currently used AR antagonists have specificity limitations.

Research Design And Methods: A Fab fragment (Fab2838) of an AR mouse monoclonal antibody can specifically bind to AR to form a complex and inhibit the activity of its receptor. We constructed the vector AntiAR, a small-molecule peptide that binds to and inhibits AR based on Fab2838.

Results: Experiments in HEK293T cells showed that peptide AntiAR of 29 peptides was the most effective among the synthesized peptides in inhibiting the AR downstream signal cAMP/PKA/CREB. In neurons, the AntiAR reversed the calcium flow change induced by the AR agonist CGS21680 (1 μM). Furthermore, AntiAR 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.

Conclusions: Antagonistic peptide AntiAR can effectively block the AR signaling pathway. This provides a new strategy for the specific inhibition of AR and provides information needed for drug development.