Leukotriene Biosynthesis and Inflammatory Mediators

Leukotrienes are bioactive lipid mediators derived from arachidonic acid through the concerted action of lipoxygenase enzymes and associated proteins, orchestrating inflammatory initiation and propagation. Following cellular stimuli, cytosolic phospholipase A₂ liberates arachidonic acid from membrane phospholipids, which is then converted by 5-lipoxygenase (5-LOX) into leukotriene A₄ (LTA₄). The fate of LTA₄ bifurcates via leukotriene A₄ hydrolase (LTA₄H), yielding the potent chemoattractant leukotriene B₄ (LTB₄), or through conjugation to form cysteinyl leukotrienes that drive bronchoconstriction and vascular permeability. The 5-LOX-activating protein (FLAP) facilitates the transfer of arachidonic acid to 5-LOX, acting as a critical regulatory node, while specialised pro-resolving mediators (SPMs) such as lipoxins and resolvins are generated by alternate lipoxygenase pathways to terminate inflammation and promote tissue repair. Imbalances between pro-inflammatory leukotrienes and pro-resolving lipid mediators underlie a spectrum of pathologies, including asthma, atherosclerosis and chronic inflammatory bowel disease. Emerging research explores the spatial dynamics of key enzymes, novel enzyme modulators and the impact of cellular phenotype on mediator profiles, underscoring the global significance of tightly regulated lipid-mediator networks for therapeutic innovation.

Research from Nature Portfolio

Recent studies have demonstrated that macrophage subsets produce distinct inflammatory and pro-resolving lipid profiles in response to pathogenic stimuli. Classically activated (M1) macrophages predominantly generate 5-LOX-derived leukotriene B₄ and prostaglandins, whereas alternatively activated (M2) macrophages favour the biosynthesis of resolvins and maresins via 15-lipoxygenase pathways, revealing a coordinated temporal regulation of inflammatory initiation and resolution by macrophage phenotype. In parallel, innovative small molecules that selectively inhibit the epoxide hydrolase activity of leukotriene A₄ hydrolase have been developed to suppress LTB₄ formation while preserving aminopeptidase-mediated degradation of pro-inflammatory peptides, offering a refined strategy to modulate leukotriene-driven inflammation without compromising endogenous anti-inflammatory processes.

Leukotriene Biosynthesis and Inflammatory Mediators publication trend

The graph below shows the total number of articles in leukotriene biosynthesis and inflammatory mediators across all publications each year (not limited to Nature Index journals).

Technical terms

Leukotriene: Inflammatory lipid mediator derived from arachidonic acid via 5-lipoxygenase, regulating vasoconstriction, vascular permeability and leukocyte chemotaxis.

5-Lipoxygenase (5-LOX): Enzyme that oxygenates arachidonic acid to generate leukotriene A₄, the precursor of pro-inflammatory leukotrienes.

Leukotriene A₄ hydrolase (LTA₄H): Bifunctional zinc metalloenzyme that converts leukotriene A₄ into leukotriene B₄ and degrades pro-inflammatory peptides.

5-Lipoxygenase-activating protein (FLAP): Membrane protein that presents arachidonic acid to 5-LOX, facilitating efficient leukotriene synthesis.

Specialised pro-resolving mediators (SPMs): Lipid mediators such as lipoxins, resolvins and protectins formed by lipoxygenases that actively drive the resolution of inflammation and tissue repair.

References

1. Airway extracellular LTA4H concentrations are governed by release from liver hepatocytes and changes in lung vascular permeability. Cell Reports (2024).
2. Differential impact of 5-lipoxygenase-activating protein antagonists on the biosynthesis of leukotrienes and of specialized pro-resolving mediators. Frontiers in Pharmacology (2023).
3. Human macrophages differentially produce specific resolvin or leukotriene signals that depend on bacterial pathogenicity. Nature Communications (2018).
4. Feasibility and physiological relevance of designing highly potent aminopeptidase-sparing leukotriene A4 hydrolase inhibitors. Scientific Reports (2017).
5. Formation, Signaling and Occurrence of Specialized Pro-Resolving Lipid Mediators—What is the Evidence so far?. Frontiers in Pharmacology (2022).