PS-BPB08-2: DEVELOPMENT OF NON-PEPTIDE TYPE OF ANGIOTENSIN II TYPE 1 RECEPTOR LIGAND AS A BIASED AGONIST

Abstract

Objective: Peptide type of angiotensin II (Ang II) type 1 (AT1) receptor ligand as a biased agonist antagonized Ang II-stimulated G protein signaling, but stimulated several kinase pathways. Here, we developed non-peptide type of AT1 receptor compound as a biased ligand. Design and method: We synthesized three non-peptide type of AT1 receptor ligands (Compound A, B and C) as candidates of biased ligands. These compounds were provided by Daiichi Sankyo Co. LTD. In vitro studies, inositol phosphate (IP) production and extracellular signal-regulated kinase (ERK) 1/2 activation were measured using AT1 receptor overexpressing cell system. We mutated the AT1 receptor (L112A, Q257A, Y292A and N295A receptors) and examined binding modes of receptor-ligand by competition binding study, and subsequently analyzed whether these ligands would induce IP production and ERK1/2 activation. Results: Kd of Compound A, B and C to AT1 wild-type receptor by competition binding study were 0.8, 21 and 48 nM, respectively. Kd of Compound A, B and C to L112A receptor were 37, 23 and 31 nM, respectively. Compound B and C decreased and increased IP production, respectively, whereas Compound A did not change IP production. Compound B and C, but not Compound A, activated ERK1/2. L112A had a key role of IP production. Conclusions: Compound A, B and C were a neutral antagonist, an inverse agonist, and an agonist with regard to IP production, respectively. On the other hand, Compound B and C, but not Compound A, were agonists to ERK1/2 activation. Thus, we developed non-peptide type of AT1 receptor compound as a biased ligand.