Received for publication September 14, 2007.
Revised November 6, 2007.
Accepted for publication November 8, 2007.

Anti-inflammatory effects of LJP 1586, an amine-based inhibitor of semicarbazide-sensitive amine oxidase activity

Abstract

Semicarbazide-sensitive amine oxidase (SSAO, AOC3, vascular adhesion protein-1, VAP-1) is a copper-containing enzyme that catalyzes the oxidative deamination of primary amines to an aldehyde, ammonia and hydrogen peroxide. SSAO is also involved in leukocyte migration to sites of inflammation, and the enzymatic activity of SSAO is essential to this role. Thus, inhibition of SSAO enzyme activity represents a target for the development of small molecule anti-inflammatory compounds. Here, we have characterized the novel SSAO inhibitor Z-3-fluoro-2-(4-methoxybenzyl)allylamine hydrochloride (LJP 1586) and assessed its anti-inflammatory activity. LJP 1586 is a potent inhibitor of rodent and human SSAO activity, with IC50 values between 4 and 43 nM. The selectivity of LJP 1586 was confirmed with a broad panel of receptors and enzymes that included the monoamine oxidases-A and -B. Oral administration of LJP 1586 resulted in complete inhibition of rat lung SSAO with an ED50 between 0.1 and 1 mg/kg, and a pharmacodynamic half-life of greater than 24 h. In a mouse model of inflammatory leukocyte trafficking oral dosing with LJP 1586 resulted in significant, dose-dependent inhibition of neutrophil accumulation, with an affect comparable to that of anti-LFA-1 antibody. In a rat model of LPS-induced lung inflammation, administration of 10 mg/kg LJP 1586 resulted in a 55% significant reduction in transmigrated cells recovered by bronchoalveolar lavage. The results demonstrate that a selective, orally active small molecule inhibitor of SSAO is an effective anti-inflammatory compound in vivo, and provide further support for SSAO as a therapeutic anti-inflammatory target.

Key words: Adhesion, Amine oxidase, Anti-inflammatory, Inflammation, Leukocyte, Trafficking