A new class of bradykinin antagonists: synthesis and in vitro activity of bissuccinimidoalkane peptide dimers

Abstract

A systematic study on the dimerization of the bradykinin (BK) antagonist D-Arg0-Arg1-Pro2-Hyp3-Gly4-Phe5-Ser6-D-Phe 7-Leu8-Arg9 has been performed. The first part of this study involved compounds wherein dimerization was carried out by sequentially replacing each amino acid with cysteine and cross-linking with bismaleimidohexane. The second part of this study utilized a series of bissuccinimidoalkane dimers wherein the intervening methylene chain was varied systematically from n = 2 to n = 12 while the point of dimerization was held constant at position 6. The biological activities of these dimers were then evaluated on BK-induced smooth muscle contraction in two different isolated tissue preparations: guinea pig ileum (GPI) and rat uterus (RU). Several of the dimeric BK antagonists displayed remarkable activities and long durations of action. In addition, dimerization at position 4, 7, 8, or 9 produced dimeric analogues with markedly reduced potency. Rank order of antagonist potency as a function of dimerization position is as follows: rat uterus, 6 greater than 5 greater than 0 greater than 2 greater than 1 greater than 3 much greater than 4, 7, 8, 9; guinea pig ileum, 6 greater than 5 greater than 3 greater than 2 greater than 1 greater than 0 much greater than 4, 7, 8, 9. Evaluation of the linker length as represented by the number of methylene units indicated an optimal distance between the two monomeric peptides of six to eight methylene moieties. These studies also revealed that the carbon-chain length significantly affected the duration of action in vitro and resulted in partial agonism effects when n greater than 8. The optimum activity in vitro was achieved with dimerization at position 6 and n = 6 (designated herein as compound 25; alternatively, CP-0127). Similar effects in potency were also seen when the monomeric antagonist D-Arg0-Arg1-Pro2-Hyp3-Gly4-Phe5-Ser6-D-Phe 7-Phe8-Arg9 (NPC-567) was dimerized using similar chemistry. These results suggest that the development of BK antagonists of significant therapeutic potential may be possible using a dimerization strategy that can overcome the heretofore limiting problems of potency and in vivo duration of action found with many of the BK antagonists in the literature.

Synthetic immunogens.

“…However, the mode of bridging can play a critical role, as recently reported by Cheronis et al [43] for bradykinin dimers and, as well documented in the present study, for the hormone gastrin even in terms of conformational space. The identical rationale can be applied to the design and expression of ef- ficient conformational epitopes.…”

Solid-phase synthesis and dimerization of an azobenzene-containing peptide as photoisomerizable proteinase inhibitor

“…The syntheses, performed by conventional solution methods [10], were not described in detail. More recently, Cheronis et al [11] described bradykinin antagonist homo-and hetero-dimers obtained using bissuccinimidoalkane cross-linkers for the selective ligation of cysteine residues included in the sequence of the monomeric peptide. Once again, the dimerization reaction was performed in solution.…”

Influence of B2 receptor antagonists on bradykinin-induced vasodilation and edema formation in isolated rabbit hindlimbs

“…The increase in potency and duration of action of CP 0127 is the result of bivalent binding cooperation and dimerization of bradykinin at position 6 with cystein [11]. Given as an intravenous bolus injection in order to measure its ability of blocking bradykinin-induced (bolus injections, intra-arterially) hypotension in the rat, the pharmacodynamic half-life of CP 0127 is approximately 20 minutes.…”

“…After termination of a continuous CP 0127 infusion its duration of action is roughly of the same magnitude in the rat and rabbit [personal communication from J.C. Cheronis, Cortech Inc.]. Recent in vitro studies have shown that CP 0127 is a potent inhibitor of bradykinin-induced smooth cell contraction in guineapig ileum and in rat uterus preparations, known to contain B2-type receptors [11]. Moreover, CP 0127 reversed lipopolysaccharide-induced hypotension in anaesthesized rats and prevent death in rats and in rabbits given lethal doses of Escherichia coli endotoxin [22].…”

“…The experiments were performed, using the two selective B 2 receptor antagonists, CP 0127 [11] and HOE 140 [12,13], to test if the bradykinin-induced effects on vascular reaction are mediated by B 2 receptors, and to study the ability of the two B 2 antagonists to counteract these effects in the isolated perfused rabbit hindlimbs model.…”