BRP-187: A potent inhibitor of leukotriene biosynthesis that acts through impeding the dynamic 5-lipoxygenase/5-lipoxygenase-activating protein (FLAP) complex assembly

• Published in: Biochemical pharmacology 2016-11, Vol.119, p.17-26
• Main Authors: Garscha, Ulrike, Voelker, Susanna, Pace, Simona, Gerstmeier, Jana, Emini, Besa, Liening, Stefanie, Rossi, Antonietta, Weinigel, Christina, Rummler, Silke, Schubert, Ulrich S., Scriba, Gerhard K.E., Çelikoğlu, Erşan, Çalışkan, Burcu, Banoglu, Erden, Sautebin, Lidia, Werz, Oliver
• Format: Article
• Language: English
• Subjects: 5-Lipoxygenase; 5-Lipoxygenase-activating protein; 5-Lipoxygenase-Activating Proteins - genetics; 5-Lipoxygenase-Activating Proteins - metabolism; Animals; Arachidonate 5-Lipoxygenase - genetics; Arachidonate 5-Lipoxygenase - metabolism; Arachidonic acid; Cell-Free System; Gene Expression Regulation, Enzymologic - drug effects; HEK293 Cells; Humans; Hydroxyurea - analogs & derivatives; Hydroxyurea - pharmacology; Indoles - pharmacology; Inflammation; Isoxazoles - chemistry; Isoxazoles - metabolism; Isoxazoles - pharmacology; Leukotriene; Leukotriene Antagonists - chemistry; Leukotriene Antagonists - metabolism; Leukotriene Antagonists - pharmacology; Leukotrienes - biosynthesis; Male; Mice; Molecular Structure; Peritonitis - chemically induced; Peritonitis - drug therapy; Quinolines - chemistry; Quinolines - metabolism; Quinolines - pharmacology; Zymosan - toxicity
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/j.bcp.2016.08.023

[Display omitted] The pro-inflammatory leukotrienes (LTs) are formed from arachidonic acid (AA) in activated leukocytes, where 5-lipoxygenase (5-LO) translocates to the nuclear envelope to assemble a functional complex with the integral nuclear membrane protein 5-LO-activating protein (FLAP). FLAP, a MAPEG family member, facilitates AA transfer to 5-LO for efficient conversion, and LT biosynthesis critically depends on FLAP. Here we show that the novel LT biosynthesis inhibitor BRP-187 prevents the 5-LO/FLAP interaction at the nuclear envelope of human leukocytes without blocking 5-LO nuclear redistribution. BRP-187 inhibited 5-LO product formation in human monocytes and polymorphonuclear leukocytes stimulated by lipopolysaccharide plus N-formyl-methionyl-leucyl-phenylalanine (IC50=7–10nM), and upon activation by ionophore A23187 (IC50=10–60nM). Excess of exogenous AA markedly impaired the potency of BRP-187. Direct 5-LO inhibition in cell-free assays was evident only at >35-fold higher concentrations, which was reversible and not improved under reducing conditions. BRP-187 prevented A23187-induced 5-LO/FLAP complex assembly in leukocytes but failed to block 5-LO nuclear translocation, features that were shared with the FLAP inhibitor MK886. Whereas AA release, cyclooxygenases and related LOs were unaffected, BRP-187 also potently inhibited microsomal prostaglandin E2 synthase-1 (IC50=0.2μM), another MAPEG member. In vivo, BRP-187 (10mg/kg) exhibited significant effectiveness in zymosan-induced murine peritonitis, suppressing LT levels in peritoneal exudates as well as vascular permeability and neutrophil infiltration. Together, BRP-187 potently inhibits LT biosynthesis in vitro and in vivo, which seemingly is caused by preventing the 5-LO/FLAP complex assembly and warrants further preclinical evaluation.