GO:0019370 leukotriene biosynthetic process: Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0019370 describes the enzymatic formation of leukotrienes, pharmacologically active lipid mediators derived from arachidonic acid.
• The pathway is initiated by 5-lipoxygenase (ALOX5) and its activating protein (ALOX5AP), which convert arachidonic acid to leukotriene A4 (LTA4).
• LTA4 is subsequently converted to leukotriene B4 (LTB4) by LTA4 hydrolase (LTA4H) or to cysteinyl leukotrienes (LTC4, LTD4, LTE4) by LTC4 synthase (LTC4S) and downstream peptidases.
• Leukotrienes are rapidly metabolized by omega- and beta-oxidation, limiting their duration of action.
• Dysregulated leukotriene biosynthesis contributes to asthma, allergic inflammation, kidney diseases, and anaphylaxis.
• CRISPR-based knockout, knock-in, and overexpression models enable causal dissection of leukotriene pathway genes in human cells and animal models.
Description
Leukotrienes are a family of lipid mediators synthesized from arachidonic acid through the concerted action of several enzymes. The Gene Ontology term GO:0019370, leukotriene biosynthetic process, encompasses the chemical reactions and pathways that lead to the formation of these pharmacologically active substances. This process is central to inflammatory and allergic responses, and its dysregulation is implicated in a range of human diseases. Understanding the molecular steps and regulatory mechanisms of leukotriene biosynthesis is therefore of broad biomedical importance.
leukotriene biosynthetic process At A Glance
| GO ID | GO:0019370 |
|---|---|
| GO term | leukotriene biosynthetic process |
| Ontology | biological_process |
| Synonym | leukotriene anabolism; leukotriene biosynthesis; leukotriene formation; leukotriene synthesis |
| Major function | Enzymatic conversion of arachidonic acid to leukotrienes, including LTA4, LTB4, LTC4, LTD4, and LTE4. |
| Key enzymes | ALOX5, ALOX5AP, LTA4H, LTC4S, and downstream peptidases. |
| Substrates | Arachidonic acid and other polyunsaturated fatty acids. |
| Products | Leukotriene A4, leukotriene B4, leukotriene C4, leukotriene D4, leukotriene E4. |
| Cellular location | Cytosol, nuclear envelope, and extracellular space for secreted leukotrienes. |
What Is GO:0019370?
GO:0019370, leukotriene biosynthetic process, is defined as the chemical reactions and pathways resulting in the formation of leukotriene, a pharmacologically active substance derived from a polyunsaturated fatty acid such as arachidonic acid. It is a biological process that includes the enzymatic conversion of arachidonic acid to leukotriene A4 and its subsequent transformation into leukotriene B4 or cysteinyl leukotrienes.
Why Is leukotriene biosynthetic process Important in Cell Biology?
Leukotrienes are potent lipid mediators that drive inflammation, bronchoconstriction, and vascular permeability. The biosynthetic process is a validated therapeutic target in asthma and allergic diseases, and emerging evidence links it to kidney injury and anaphylaxis. Studying GO:0019370 helps researchers identify new drug targets and biomarkers for inflammatory disorders.
• Leukotrienes are key mediators of allergic inflammation and asthma.
• The pathway is targeted by anti-leukotriene drugs used in asthma therapy.
• Cysteinyl leukotrienes promote gut absorption of food allergens and anaphylaxis in mice.
• Leukotriene biosynthesis is implicated in kidney diseases, including glomerulonephritis.
• LTA4H is a bifunctional enzyme with epoxide hydrolase and aminopeptidase activities.
• Metabolism of leukotrienes by beta-oxidation regulates their biological half-life.
• Genetic variants in ALOX5 and ALOX5AP are associated with inflammatory disease susceptibility.
• The pathway provides opportunities for CRISPR-based functional genomics in immune cells.
What Happens During leukotriene biosynthetic process?
Release of arachidonic acid and initial oxidation by 5-lipoxygenase
In simple terms: The process starts when arachidonic acid is freed from cell membranes and then modified by an enzyme called 5-lipoxygenase.
Arachidonic acid is liberated from membrane phospholipids by phospholipase A2 and is subsequently oxidized by 5-lipoxygenase (ALOX5) in concert with 5-lipoxygenase-activating protein (ALOX5AP) to form 5-hydroperoxyeicosatetraenoic acid (5-HPETE) and then leukotriene A4 (LTA4). This step is rate-limiting and requires calcium and ATP.
Formation of leukotriene A4 and its conversion to leukotriene B4
In simple terms: LTA4 is a short-lived intermediate that can be converted into leukotriene B4, a potent attractant for immune cells.
LTA4 is hydrolyzed by leukotriene A4 hydrolase (LTA4H) to leukotriene B4 (LTB4). LTA4H is a zinc-dependent enzyme with epoxide hydrolase activity, and its product LTB4 acts through BLT1 and BLT2 receptors to recruit neutrophils and other leukocytes.
Synthesis of cysteinyl leukotrienes (LTC4, LTD4, LTE4)
In simple terms: LTA4 can also be conjugated with glutathione to form cysteinyl leukotrienes, which cause airway constriction and vascular leakage.
LTC4 synthase (LTC4S) conjugates LTA4 with reduced glutathione to form leukotriene C4 (LTC4). LTC4 is exported and sequentially converted by gamma-glutamyl transpeptidase and dipeptidase to LTD4 and LTE4, respectively. These cysteinyl leukotrienes act via CysLT1 and CysLT2 receptors to mediate bronchoconstriction and inflammation.
Metabolism and inactivation of leukotrienes
In simple terms: Leukotrienes are broken down by oxidation to stop their signaling.
Leukotrienes undergo omega-oxidation and beta-oxidation to inactive metabolites, primarily in the liver and kidney. Beta-oxidation of eicosanoids shortens their half-life and limits systemic effects. This metabolic step is important for terminating inflammatory responses.
Key Genes Involved in GO:0019370 leukotriene biosynthetic process
The following genes encode enzymes and proteins directly involved in the leukotriene biosynthetic process.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ALOX5 | Converts arachidonic acid to 5-HPETE and LTA4 | Rate-limiting enzyme; target of zileuton; knockout models show reduced inflammation |
| ALOX5AP | Activates ALOX5 and facilitates LTA4 synthesis | Genetic variants linked to asthma and cardiovascular disease |
| LTA4H | Hydrolyzes LTA4 to LTB4 | Bifunctional enzyme; target for anti-inflammatory drugs |
| LTC4S | Conjugates LTA4 with glutathione to form LTC4 | Key enzyme for cysteinyl leukotriene synthesis |
| GGT1 | Converts LTC4 to LTD4 | Gamma-glutamyl transpeptidase; regulates cysteinyl leukotriene levels |
| DPEP1 | Converts LTD4 to LTE4 | Dipeptidase; terminal step in cysteinyl leukotriene synthesis |
| PLA2G4A | Releases arachidonic acid from membrane phospholipids | Upstream regulator of substrate availability |
| CysLT1R | Receptor for cysteinyl leukotrienes | Target of montelukast; mediates bronchoconstriction |
| CysLT2R | Receptor for cysteinyl leukotrienes | Modulates vascular permeability and inflammation |
| BLT1 | Receptor for LTB4 | Mediates neutrophil chemotaxis |
| BLT2 | Receptor for LTB4 | Low-affinity receptor; involved in inflammation |
| 5-LOX | Alternative name for ALOX5 | Enzyme target in asthma research |
| FLAP | Alternative name for ALOX5AP | Drug target for leukotriene synthesis inhibitors |
| LTA4H | Also has aminopeptidase activity | Potential role in peptide processing |
| MGST2 | Microsomal glutathione S-transferase 2 | Can synthesize LTC4 in some tissues |
| MGST3 | Microsomal glutathione S-transferase 3 | Alternative LTC4 synthase |
| ABCC1 | Multidrug resistance protein 1 | Exports LTC4 from cells |
| SLCO2A1 | Prostaglandin transporter | May transport leukotrienes |
How Is leukotriene biosynthetic process Regulated?
Leukotriene biosynthesis is regulated at multiple levels. ALOX5 activity requires calcium and ATP and is modulated by phosphorylation. ALOX5AP expression is induced by inflammatory stimuli, and its gene variants affect pathway flux. LTA4H and LTC4S expression are regulated by cytokines and growth factors. Additionally, beta-oxidation and omega-oxidation of leukotrienes provide metabolic control.
leukotriene biosynthetic process and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ALOX5 | Asthma, allergic rhinitis | Knockout mouse or human airway epithelial cells |
| ALOX5AP | Asthma, cardiovascular disease | Knock-in of risk variants in cell lines |
| LTA4H | Inflammation, kidney injury | LTA4H knockout zebrafish or mouse |
| LTC4S | Anaphylaxis, asthma | LTC4S knockout mast cells |
| CysLT1R | Asthma, allergic inflammation | Receptor overexpression in HEK293 cells |
Asthma and allergic inflammation
Cysteinyl leukotrienes are major mediators of bronchoconstriction and airway inflammation in asthma. Polymorphisms in ALOX5 and ALOX5AP are associated with asthma susceptibility and response to leukotriene-modifying drugs. Cysteinyl leukotrienes also stimulate gut absorption of food allergens to promote anaphylaxis in mice.
Kidney diseases
Leukotrienes contribute to renal inflammation and injury. LTB4 and cysteinyl leukotrienes are implicated in glomerulonephritis, diabetic nephropathy, and ischemia-reperfusion injury. Targeting the leukotriene pathway may offer therapeutic benefits in kidney diseases.
Cardiovascular and other inflammatory disorders
Leukotriene biosynthesis has been linked to atherosclerosis, cardiovascular disease, and inflammatory bowel disease. The pathway is a source of biomarkers and drug targets for these conditions.
From leukotriene biosynthetic process-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does ALOX5 loss reduce leukotriene production? | ALOX5 knockout in HL-60 or primary human neutrophils |
| Does a point mutation in LTA4H alter enzymatic activity? | LTA4H point-mutation knock-in in HEK293 cells |
| Can LTC4S overexpression increase cysteinyl leukotriene levels? | LTC4S overexpression in mast cells or eosinophils |
| Does tagging ALOX5 affect its subcellular localization? | ALOX5 tagged knock-in with GFP in human cell lines |
| Does ALOX5AP knockout impair leukotriene synthesis? | ALOX5AP knockout in macrophage-like cells |
| Can CRISPR library screening identify novel regulators? | Genome-wide knockout library in leukotriene-producing cells |
How to Study the leukotriene biosynthetic process Process
| Method | What It Measures | Typical Application |
|---|---|---|
| LC-MS/MS | Leukotriene levels | Quantification in cell culture and tissues |
| Enzyme activity assay | Catalytic activity of ALOX5, LTA4H, LTC4S | Inhibitor screening and kinetic studies |
| CRISPR knockout screen | Gene essentiality for leukotriene production | Discovery of novel pathway regulators |
| RNA-seq | Transcript levels of pathway genes | Expression profiling in inflammatory models |
| Proteomics | Protein abundance and modifications | Post-translational regulation studies |
| Immunofluorescence | Subcellular localization of enzymes | Visualization of ALOX5 and LTA4H |
| ELISA | Concentration of LTB4 or LTC4 | High-throughput sample screening |
| Flow cytometry | Leukotriene receptor expression | Immune cell phenotyping |
Quantification of leukotrienes by LC-MS/MS
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the gold standard for measuring leukotriene levels in biological samples. It allows simultaneous quantification of LTB4, LTC4, LTD4, and LTE4 with high sensitivity and specificity.
Enzyme activity assays
Enzymatic activities of ALOX5, LTA4H, and LTC4S can be measured using specific substrates and HPLC or spectrophotometric detection. These assays help determine kinetic parameters and inhibitor efficacy.
CRISPR-based genetic screens
Genome-wide CRISPR knockout or activation screens can identify genes that regulate leukotriene biosynthesis. Such screens have been used to uncover novel modulators of inflammatory lipid pathways.
Transcriptomics and proteomics
RNA-seq and proteomics can reveal expression changes in leukotriene pathway genes under inflammatory conditions. These approaches help identify regulatory networks and biomarkers.
How CRISPR Can Be Used to Study GO:0019370 leukotriene biosynthetic process
Knockout
CRISPR knockout of ALOX5, ALOX5AP, LTA4H, or LTC4S can abolish leukotriene production, providing causal evidence for their roles. Knockout cell lines are valuable for drug target validation and pathway dissection.
Point Mutation
Introducing point mutations in LTA4H or ALOX5 can mimic naturally occurring variants and reveal their impact on enzyme activity and disease susceptibility. This approach helps link genotype to biochemical phenotype.
Knock-in
Knock-in of tagged versions of ALOX5 or LTC4S allows tracking of protein localization and interactions in live cells. Knock-in of disease-associated alleles can model human inflammatory disorders.
Overexpression
Overexpression of LTC4S or LTA4H in cell lines can enhance leukotriene synthesis and mimic inflammatory states. This is useful for studying downstream signaling and receptor activation.
How EDITGENE Supports leukotriene biosynthetic process Research
Researchers studying leukotriene biosynthetic process-related genes often need to determine whether a candidate gene is causally involved in leukotriene production, inflammation, or disease progression. EDITGENE provides a comprehensive suite of CRISPR services to enable such functional studies with high precision and reproducibility.
Contact EDITGENE today to design your custom CRISPR model for leukotriene biosynthetic process research.
Frequently Asked Questions About leukotriene biosynthetic process
What is GO:0019370?
GO:0019370 is the Gene Ontology term for leukotriene biosynthetic process, the set of chemical reactions that produce leukotrienes from arachidonic acid.
What genes are involved in leukotriene biosynthetic process?
Key genes include ALOX5, ALOX5AP, LTA4H, LTC4S, GGT1, and DPEP1.
What are the products of leukotriene biosynthesis?
The main products are leukotriene A4, leukotriene B4, and cysteinyl leukotrienes LTC4, LTD4, and LTE4.
How are leukotrienes synthesized?
Arachidonic acid is oxidized by 5-lipoxygenase to LTA4, which is then converted to LTB4 or cysteinyl leukotrienes by specific enzymes.
What diseases are associated with leukotriene biosynthesis?
Asthma, allergic inflammation, anaphylaxis, and kidney diseases are linked to dysregulated leukotriene production.
How can CRISPR be used to study leukotriene biosynthesis?
CRISPR knockout, knock-in, and overexpression models can disrupt or modify pathway genes to assess their function in leukotriene production.
What is the role of ALOX5 in leukotriene biosynthesis?
ALOX5 catalyzes the first committed step, converting arachidonic acid to 5-HPETE and then LTA4.
What is LTA4H?
LTA4H is leukotriene A4 hydrolase, the enzyme that converts LTA4 to LTB4.
How are leukotrienes measured?
LC-MS/MS and ELISA are commonly used to quantify leukotriene levels in biological samples.
What is the difference between LTB4 and cysteinyl leukotrienes?
LTB4 is a neutrophil chemoattractant, while cysteinyl leukotrienes (LTC4, LTD4, LTE4) mediate bronchoconstriction and vascular permeability.
Conclusion
GO:0019370, leukotriene biosynthetic process, is a central metabolic pathway in inflammation and allergy. Its enzymes and receptors are validated drug targets, and ongoing research continues to uncover new regulatory mechanisms and disease links. CRISPR-based models offer powerful tools to dissect this pathway and identify novel therapeutic opportunities.
References
- 1. Wang B et al.. 2021. Metabolism pathways of arachidonic acids: mechanisms and potential therapeutic targets.. Signal Transduct Target Ther 6(1):94 PMID: 33637672
- 2. Hammarström S. 1983. Leukotrienes.. Annu Rev Biochem 52:355-77 PMID: 6311078
- 3. Hoyt LR et al.. 2025. Cysteinyl leukotrienes stimulate gut absorption of food allergens to promote anaphylaxis in mice.. Science 389(6760):eadp0240 PMID: 40773557
- 4. Haeggström JZ et al.. 2002. Leukotriene A4 hydrolase.. Prostaglandins Other Lipid Mediat 68-69:495-510 PMID: 12432939
- 5. Ford-Hutchinson AW et al.. 1994. 5-Lipoxygenase.. Annu Rev Biochem 63:383-417 PMID: 7979243
- 6. Hammarström S et al.. 1985. Metabolism of leukotrienes.. Mol Cell Biochem 69(1):7-16 PMID: 3001504
- 7. Diczfalusy U. 1994. Beta-oxidation of eicosanoids.. Prog Lipid Res 33(4):403-28 PMID: 7870740
- 8. Rubinstein M et al.. 2018. Leukotrienes and kidney diseases.. Curr Opin Nephrol Hypertens 27(1):42-48 PMID: 29059080
