Anti-Inflammatory Effects of LJP 1586 [Z-3-Fluoro-2-(4-methoxybenzyl)allylamine Hydrochloride], an Amine-Based Inhibitor of Semicarbazide-Sensitive Amine Oxidase Activity

Abstract

Semicarbazide-sensitive amine oxidase (SSAO, amine oxidase, copper-containing 3, and vascular adhesion protein-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 IC 50 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 ED 50 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 effect comparable to that of anti-leukocyte function-associated antigen-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.Semicarbazide-sensitive amine oxidase [SSAO, AOC3, and vascular adhesion protein-1 (VAP-1)] is a copper-and topaquinone (TPQ) cofactor-containing enzyme that performs the oxidative deamination of primary amines. Endogenous substrates for SSAO include methylamine, formed from adrenaline and creatine metabolism, and aminoacetone, a product of amino acid catabolism. The active enzyme is a dimer and exists as both a type II transmembrane protein and in soluble form in plasma (for reviews see Boomsma et al

Small-Molecule Inhibitors of Vascular Adhesion Protein-1 Reduce the Accumulation of Myeloid Cells into Tumors and Attenuate Tumor Growth in Mice

“…These data imply that the cytotoxic or suppressor T cells may rely more on the Ab-defined epitope of VAP-1 than the SSAO activity of VAP-1 in the accumulation process. The sequential use of both functional modalities (the Ab-defined epitope and the SSAO activity) of VAP-1 has been shown to be important in interactions between endothelial cells and lymphocytes or granulocytes (8)(9)(10)(11)(13)(14)(15)(16)(17)(18)(19)(20). Inhibition of the catalytic SSAO activity of VAP-1 through using SZE5302 effectively retarded Gr-1 +…”

“…Targeting ectoenzymes, such as VAP-1, is relatively easy, because the catalytically active site is outside the plasma membrane and the crystal structure of the molecule has been solved (44). In fact, multiple small-molecule VAP-1 inhibitors have been developed recently, and they are being tested for anti-inflammatory purposes (17,23,24). However, anti-VAP-1 Abs that are also being tested as anti-inflammatory drugs should not have potential tumor immunity-related side effects, inasmuch they do not affect angiogenesis or tumor growth.…”

“…We show that two different enzyme inhibitors, but not the anti-VAP-1 Abs, attenuated myeloid cell accumulation in the tumors and impaired tumor development and neoangiogenesis. Because blocking of VAP-1 function effectively attenuates inflammatory reactions in vivo, therapeutics aimed at inhibition of VAP-1 are being actively developed to treat inflammatory disorders (17,23,24). These data suggest that the SSAO inhibitors may be a future adjuvant for immunotherapy in cancer.…”

“…The anti-VAP-1 Abs inhibit leukocyte-endothelial interactions in several in vitro and in vivo models (8)(9)(10)(11)(12)(13)(14). The small-molecule SSAO inhibitors also effectively attenuate inflammation by diminishing leukocyte rolling, firm adhesion, and transmigration through multiple types of endothelial cells (9,13,(15)(16)(17)(18)(19)(20). Notably, the anti-VAP-1 Abs do not inhibit the enzymatic activity of VAP-1, and the enzyme inhibitors do not alter the mAb-defined surface epitopes of VAP-1 (8,15).…”

Ischemia‐reperfusion injury is attenuated in VAP‐1‐deficient mice and by VAP‐1 inhibitors

“…In a recent report, a different SSAO inhibitor LJP1207 was shown to decrease tissue damage in a stroke model in rats rendered exquisitely sensitive to IRI in the brain [39]. Moreover, administration of SSAO inhibitor has been shown to reduce leukocyte infiltration in LPS-induced pulmonary inflammation [40,41]. Notably, while LPS inhalation in the lungs causes a direct lung injury and mimics pneumonia, intestinal IR triggers systemic inflammation and subsequent indirect ALI.…”