Shifting the Biosynthesis of Leukotrienes Toward Specialized Pro-Resolving Mediators by the 5-Lipoxygenase-Activating Protein (FLAP) Antagonist BRP-201

Abstract

Background and Purpose: Lipid mediators (LM) play crucial roles in the complex inflammation process with respect to initiation, maintenance, and resolution. Proinflammatory leukotrienes (LTs), generated by 5-lipoxygenase (LOX) and the 5-LOX-activating protein (FLAP), initiate and maintain inflammation while specialized pro-resolving mediators (SPMs) formed by various LOXs as key enzymes promote inflammation resolution and the return to homeostasis. Since 5-LOX also contributes to SPM biosynthesis, smart pharmacological manipulation of the 5-LOX pathway and accompanied activation of 12-/15-LOXs may accomplish suppression of LT formation but maintain or even elevate SPM formation. Here, we demonstrated that the FLAP antagonist BRP-201 possesses such pharmacological profile and causes a switch from LT toward SPM formation. Methods and Results: Comprehensive LM metabololipidomics with activated human monocyte-derived macrophages (MDM) of M1 or M2 phenotype showed that BRP-201 strongly inhibits LT formation induced by bacterial exotoxins. In parallel, SPM levels and 12/15-LOX-derived products were markedly elevated, in particular in M2-MDM. Intriguingly, in unstimulated MDM, BRP-201 induced formation of 12/15-LOX products including SPM and caused 15-LOX-1 subcellular redistribution without affecting 5-LOX. Experiments with HEK293 cells stably expressing either 5-LOX with or without FLAP, 15-LOX-1 or 15-LOX-2 confirmed suppression of 5-LOX product formation due to FLAP antagonism by BRP-201 but activated 15-LOX-1 in the absence of FLAP. Finally, in zymosan-induced murine peritonitis, BRP-201 (2 mg/kg, ip) lowered LT levels but elevated 12/15-LOX products including SPMs. Conclusion: BRP-201 acts as FLAP antagonist but also as 12/15-LOX activator switching formation of pro-inflammatory LTs toward inflammation-resolving SPM, which reflects a beneficial pharmacological profile for intervention in inflammation.

Intestinal epithelial BLT1 promotes mucosal repair

“…Proinflammatory leukotrienes, generated by 5-lipoxygenase (LOX) and the 5-LOX-activating protein (FLAP), initiate, and maintain inflammation while specialized pro-resolving mediators (SPMs) generated by various LOXs promote resolution and repair (27,28). Since 5-LOX also contributes to SPM biosynthesis, pharmacological manipulation of the 5-LOX pathway and activation of 12-/15-LOXs might cause suppression of leukotriene formation and maintain SPM generation.…”

“…Importantly, we observed delayed wound healing in 2D colonoids deficient in BLT1, suggesting that epithelial cells may produce LTB 4 in an autocrine fashion to promote wound healing or that epithelial BLT1 directly regulates expression of molecules involved in the repair process. Proinflammatory leukotrienes, generated by 5-lipoxygenase (5-LOX) and the 5-LOX–activating protein, initiate and maintain inflammation while SPMs generated by various LOXs promote resolution and repair ( 27 , 28 ). Since 5-LOX also contributes to SPM biosynthesis, pharmacological manipulation of the 5-LOX pathway and activation of 12-/15-LOXs might cause suppression of leukotriene formation and maintain SPM generation.…”

PEG–Lipid–PLGA Hybrid Particles for Targeted Delivery of Anti-Inflammatory Drugs

“…The drug BRP-201 acts as a 5-LOX activating protein (FLAP) inhibitor with an IC 50 value of 50 nM [ 26 ]. It belongs to a new class of anti-inflammatory drugs with superior properties compared to the current anti-inflammatory therapies available [ 26 , 27 , 28 ]. However, BRP-201 is a lipophilic drug with a very low water solubility and hence low bioavailability, which is why it relies on an encapsulation into a suitable DDS [ 29 ].…”

Frankincense preparation promotes formation of inflammation-resolving lipid mediators by manipulating lipoxygenases in human innate immune cells

“…Currently, no pharmacological treatments are approved to stimulate endogenous SPM biosynthesis for promoting inflammation resolution. However, small molecules were recently discovered that favorably modulate the LM biosynthetic network by shifting the production of LTs toward SPM in activated leukocytes and/or even actively elicit SPM formation ( Gerstmeier et al, 2019 ; Werner et al, 2019 ; Gilbert et al, 2020 ; Pace et al, 2021 ; Kretzer et al, 2022a ; Kretzer et al, 2022b ; Borner et al, 2023 ). These compounds act by different mechanisms, invoking a regiospecificity shift of 5-LOX toward the 12/15-lipoxygenating enzyme ( Gilbert et al, 2020 ), activating 15-LOX ( Kretzer et al, 2022b ; Borner et al, 2023 ), or interfering with 5-LOX-activating protein (FLAP) ( Kretzer et al, 2022a ).…”

“…However, small molecules were recently discovered that favorably modulate the LM biosynthetic network by shifting the production of LTs toward SPM in activated leukocytes and/or even actively elicit SPM formation ( Gerstmeier et al, 2019 ; Werner et al, 2019 ; Gilbert et al, 2020 ; Pace et al, 2021 ; Kretzer et al, 2022a ; Kretzer et al, 2022b ; Borner et al, 2023 ). These compounds act by different mechanisms, invoking a regiospecificity shift of 5-LOX toward the 12/15-lipoxygenating enzyme ( Gilbert et al, 2020 ), activating 15-LOX ( Kretzer et al, 2022b ; Borner et al, 2023 ), or interfering with 5-LOX-activating protein (FLAP) ( Kretzer et al, 2022a ). Among these molecules, the pentacyclic triterpene 3- O -acetyl-11-keto-β-boswellic acid (AKBA), found in the gum resin of Boswellia serrata (termed frankincense), acts as molecular switch blocking LT formation but stimulating SPM production by allosteric modulation of 5- and 15-LOX isoforms ( Gilbert et al, 2020 ; Gilbert et al, 2021 ; Borner et al, 2023 ).…”