Functional coupling of human adenosine receptors to a ligand-dependent reporter gene system.

We have stably transfected CHO cells that have integrated in their genome a reporter gene under the control of promoter sequences containing several copies of the cAMP response element, CRE, with different human adenosine receptors: A1, A2a and A2b. The new cell lines responded to the addition of known adenosine agonists and antagonists with changes in the expression of the reporter gene. The activity of the reporter gene can be easily monitored by bioluminescence. Although adenosine receptors are divergently coupled to adenylate cyclase, A1 receptors inhibit whereas A2 stimulate, changes in gene expression faithfully reflected the negative and positive coupling of the receptors. We have used the system to examine the pharmacological profile of the human receptors expressed in CHO cells.