ABSTRACT
BACKGROUND AND PURPOSE: Leukotrienes (LTs) are inflammatory mediators produced via the 5-lipoxygenase (5-LOX) pathway and are linked to diverse disorders, including asthma, allergic rhinitis and cardiovascular diseases. We recently identified the benzimidazole derivative BRP-7 as chemotype for anti-LT agents by virtual screening targeting 5-LOX-activating protein (FLAP). Here, we aimed to reveal the in vitro and in vivo pharmacology of BRP-7 as an inhibitor of LT biosynthesis. EXPERIMENTAL APPROACH: We analysed LT formation and performed mechanistic studies in human neutrophils and monocytes, in human whole blood (HWB) and in cell-free assays. The effectiveness of BRP-7 in vivo was evaluated in rat carrageenan-induced pleurisy and mouse zymosan-induced peritonitis. KEY RESULTS: BRP-7 potently suppressed LT formation in neutrophils and monocytes and this was accompanied by impaired 5-LOX co-localization with FLAP. Neither the cellular viability nor the activity of 5-LOX in cell-free assays was affected by BRP-7, indicating that a functional FLAP is needed for BRP-7 to inhibit LTs, and FLAP bound to BRP-7 linked to a solid matrix. Compared with the FLAP inhibitor MK-886, BRP-7 did not significantly inhibit COX-1 or microsomal prostaglandin E2 synthase-1, implying the selectivity of BRP-7 for FLAP. Finally, BRP-7 was effective in HWB and impaired inflammation in vivo, in rat pleurisy and mouse peritonitis, along with reducing LT levels. CONCLUSIONS AND IMPLICATIONS: BRP-7 potently suppresses LT biosynthesis by interacting with FLAP and exhibits anti-inflammatory effectiveness in vivo, with promising potential for further development.
Subject(s)
5-Lipoxygenase-Activating Protein Inhibitors/pharmacology , Anti-Inflammatory Agents/pharmacology , Benzimidazoles/pharmacology , Leukotriene Antagonists/pharmacology , Leukotrienes/biosynthesis , 5-Lipoxygenase-Activating Proteins/metabolism , Animals , Arachidonate 5-Lipoxygenase/metabolism , Carrageenan , Cells, Cultured , Disease Models, Animal , Dose-Response Relationship, Drug , Down-Regulation , Humans , Male , Mice , Monocytes/drug effects , Monocytes/enzymology , Neutrophils/drug effects , Neutrophils/enzymology , Peritonitis/chemically induced , Peritonitis/enzymology , Peritonitis/prevention & control , Pleurisy/chemically induced , Pleurisy/enzymology , Pleurisy/prevention & control , Rats, Wistar , ZymosanABSTRACT
The aim was to define blood rheology in progressive systemic scleroderma (PSS). 55 patients were compared to controls. Blood and plasma viscosity, hematocrit, red cell aggregation, and deformability were measured. Except for hematocrit, all these variables are significantly altered, indicating a loss of blood fluidity in PSS. Drugs had no obvious effect on blood rheology, but the clinical picture did. The loss of blood fluidity in PSS is suggested to play a pathophysiological role in the initiation of Raynaud phenomena, from which all patients suffered.
