PROTEIN-KINASE-C REGULATES ADENOSINE A2A RECEPTOR MESSENGER-RNA EXPRESSION IN SH-SY5Y CELLS

Protein kinase C regulates mRNAs encoding several G protein-linked rec eptors but its role in adenosine A2a receptor expression is not known. We tested the hypothesis that protein kinase C activated by tetradeca noyl phorbol acetate (TPA) regulates adenosine A2a receptor mRNA level s. SH-SY5Y human neuroblastoma cells express adenosine receptors which positively couple to adenylyl cyclase with a pharmacologic profile ex pected of the A2a subtype. Northern blotting demonstrated an adenosine A2a receptor mRNA species of similar molecular size in SH-SY5Y cells and in human brain. TPA increased adenosine A2a receptor mRNA in a dos e-and time-dependent fashion. Transcription or translation inhibition prevented increases in adenosine A2a receptor mRNA. Bisindolylmaleimid e blocked TPA effects. Adenosine A2a receptor mRNA stability was uncha nged by TPA. This study identifies a human neuroblastoma cell line exp ressing functional adenosine A2a receptors. Protein kinase C activatio n appears to enhance transcription of the adenosine A2a receptor gene. (C) 1997 Elsevier Science B.V.