Development of a selective peptide antagonist for the human natriuretic peptide receptor-B

Activation by C-type natriuretic peptide (CNP) of its receptor NPRB results in venodilation and inhibition of cellular proliferation. NPRB-selective antagonists should be useful to understand their physiological implications. We previously observed that [Thr9,Ser11,Arg16](N,C-ANP)pBNP (P12) is an antagonist for bNPRB and a potent agonist for bNPRA. The antagonist [Ser11](N-CNP,C-ANP)pBNP(2-26) (P18) displays six-fold selectivity towards hNPRB versus hNPRA. Deletion of the C-terminus in [Ser11](N-CNP,C-ANP)pBNP(2-25) (P19) decreases its affinity for hNPRA but improves its selectivity 35-fold. Peptide libraries based on P19 using phage display methodology yielded two positive clones P20 and P21. P19 behaves as the most potent antagonist, but P20 is the most selective.