GO:0097257 leukotriene B4 12-hydroxy dehydrogenase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0097257 describes the NADP+-dependent oxidation of leukotriene B4 (LTB4) to 12-oxo-LTB4, a reaction that inactivates the potent neutrophil chemoattractant LTB4.
• The reaction is catalyzed by enzymes with 12-hydroxydehydrogenase activity, including members of the prostaglandin reductase family such as PTGR1.
• This activity is part of the eicosanoid metabolic network that controls the half-life and biological potency of LTB4 in inflammation and immunity.
• LTB4 and its metabolites signal through BLT1 and BLT2 receptors, influencing chemotaxis, angiogenesis, and vascular pathology.
• Dysregulation of LTB4 metabolism has been linked to inflammatory diseases, vascular degeneration, and host-pathogen interactions.
• CRISPR-based knockout, point-mutation, and overexpression models are essential to dissect the causal role of GO:0097257 enzymes in disease.
Description
Leukotriene B4 (LTB4) is a potent lipid mediator derived from arachidonic acid that drives neutrophil chemotaxis and inflammation. The biological activity of LTB4 is terminated by its conversion to 12-oxo-LTB4, a reaction catalyzed by enzymes exhibiting leukotriene B4 12-hydroxy dehydrogenase activity (GO:0097257). This oxidation step is NADP+-dependent and represents a key node in eicosanoid catabolism. Understanding GO:0097257 is critical because it controls the local concentration of LTB4 and thus the intensity and duration of inflammatory responses. Moreover, LTB4 and its metabolites act through the low-affinity receptor BLT2 to modulate angiogenesis and vascular integrity, linking this enzymatic activity to vascular biology. Researchers studying inflammation, vascular disease, and host-pathogen interactions therefore need robust tools to manipulate and measure this activity.
leukotriene B4 12-hydroxy dehydrogenase activity At A Glance
| GO ID | GO:0097257 |
|---|---|
| GO term | leukotriene B4 12-hydroxy dehydrogenase activity |
| Ontology | molecular_function |
| Synonym | leukotriene B4 12-hydroxydehydrogenase activity |
| Definition | Catalysis of the reaction: leukotriene B4 + NADP+ = 12-oxo-leukotriene B4 + NADPH + H+. |
| Major function | Oxidation of leukotriene B4 to 12-oxo-leukotriene B4, reducing NADP+ to NADPH |
| Cofactor | NADP+ (nicotinamide adenine dinucleotide phosphate) |
| Substrate | Leukotriene B4 (LTB4) |
| Product | 12-oxo-leukotriene B4 |
| Related enzymes | Prostaglandin reductase 1 (PTGR1) and other 12-hydroxydehydrogenases |
What Is GO:0097257?
GO:0097257 is a molecular function term defined as the catalysis of the reaction: leukotriene B4 + NADP+ = 12-oxo-leukotriene B4 + NADPH + H+. In other words, it is the NADP+-dependent oxidation of the 12-hydroxy group of LTB4 to a ketone, yielding 12-oxo-LTB4 and NADPH. This activity is synonymous with leukotriene B4 12-hydroxydehydrogenase activity and belongs to the oxidoreductase class of enzymes.
Why Is leukotriene B4 12-hydroxy dehydrogenase activity Important in Cell Biology?
GO:0097257 is important because it directly regulates the lifetime and biological activity of LTB4, a central mediator of acute and chronic inflammation. By converting LTB4 to 12-oxo-LTB4, this activity limits neutrophil recruitment and prevents excessive tissue damage. At the same time, 12-oxo-LTB4 and related metabolites can act as ligands for BLT2, influencing angiogenesis and vascular tone. Thus, the enzyme(s) carrying this activity sit at the interface of lipid signaling, inflammation, and vascular biology. Dysregulation of this step has been implicated in inflammatory diseases, vascular degeneration, and impaired host defense against intracellular pathogens. Consequently, targeting GO:0097257 could offer therapeutic opportunities, and understanding its regulation is a priority for researchers in immunology and vascular biology.
• Controls the half-life of LTB4, a potent neutrophil chemoattractant.
• Modulates inflammatory responses by inactivating LTB4.
• Generates 12-oxo-LTB4, which can influence BLT2-mediated signaling.
• Impacts angiogenesis and vascular stability through LTB4/BLT2 axis.
• Plays a role in host defense against Leishmania amazonensis in macrophages.
• Linked to vascular degeneration, dissection, and rupture via 12-HETE and BLT2.
• Potential target for anti-inflammatory drug development.
• Enzymes with this activity are expressed in neutrophils, macrophages, and other immune cells.
• Provides a metabolic checkpoint for eicosanoid balance.
• Relevant to diseases such as atherosclerosis, arthritis, and inflammatory bowel disease.
Molecular Mechanism of leukotriene B4 12-hydroxy dehydrogenase activity
Substrate recognition and binding
In simple terms: The enzyme grabs LTB4 and holds it in place for chemical modification.
The enzyme binds leukotriene B4 (LTB4) with stereospecificity, recognizing the 12-hydroxy group. Studies on human prostaglandin reductase 1 (PTGR1) show that it accepts LTB4 as a substrate, with site-directed mutagenesis identifying residues critical for substrate binding and catalysis. The binding pocket accommodates the hydroxylated eicosanoid, positioning it for hydride transfer to NADP+.
Catalytic oxidation and NADP+ reduction
In simple terms: The enzyme removes hydrogen from LTB4 and transfers it to NADP+, turning LTB4 into 12-oxo-LTB4.
The catalytic mechanism involves oxidation of the 12-hydroxy group of LTB4 to a ketone, yielding 12-oxo-LTB4, while NADP+ is reduced to NADPH and a proton is released. This reaction is characteristic of 12-hydroxydehydrogenase activity. The enzyme likely employs a general acid-base mechanism, with a conserved tyrosine or lysine residue facilitating hydride transfer, as suggested by mutagenesis studies on PTGR1.
Cofactor specificity and regeneration
In simple terms: The enzyme uses NADP+ as a cofactor and needs it to be recycled for continued activity.
GO:0097257 specifically requires NADP+ as the electron acceptor, distinguishing it from NAD+-dependent dehydrogenases. The resulting NADPH must be reoxidized by cellular pathways to maintain enzyme activity. The preference for NADP+ links this activity to cellular redox status and pentose phosphate pathway flux.
Regulation by inhibitors and cellular context
In simple terms: Certain molecules can block the enzyme, and its activity depends on the cell type and inflammatory signals.
Inhibitor studies on PTGR1 have identified compounds that interfere with its dehydrogenase activity, providing tools to probe the role of GO:0097257 in cells. Additionally, the expression of enzymes with this activity can be regulated by inflammatory stimuli, as seen in macrophages where LTB4 modulates P2X7 receptor-mediated functions. The cellular redox environment and substrate availability further influence the flux through this reaction.
Key Genes Involved in GO:0097257 leukotriene B4 12-hydroxy dehydrogenase activity
The following genes and proteins are associated with leukotriene B4 12-hydroxy dehydrogenase activity or related eicosanoid metabolism.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PTGR1 | Prostaglandin reductase 1; exhibits 12-hydroxydehydrogenase activity toward LTB4 | Model to study substrate specificity and inhibitor design |
| ALOX5 | 5-lipoxygenase; initiates LTB4 biosynthesis | Upstream regulator of LTB4 levels |
| ALOX5AP | 5-lipoxygenase activating protein; required for LTB4 synthesis | Target for anti-inflammatory drugs |
| LTA4H | Leukotriene A4 hydrolase; converts LTA4 to LTB4 | Determines LTB4 production |
| LTB4R | BLT1 receptor; mediates LTB4 chemotaxis | Key for neutrophil recruitment |
| LTB4R2 | BLT2 receptor; binds LTB4 and 12-HETE | Implicated in angiogenesis and vascular disease |
| CBR1 | Carbonyl reductase 1; may exhibit 12-hydroxydehydrogenase activity | Potential alternative enzyme |
| AKR1C1 | Aldo-keto reductase family 1 member C1; eicosanoid metabolism | May contribute to LTB4 oxidation |
| AKR1C2 | Aldo-keto reductase family 1 member C2; eicosanoid metabolism | Potential role in LTB4 catabolism |
| AKR1C3 | Aldo-keto reductase family 1 member C3; prostaglandin metabolism | Broad substrate specificity |
| PTGR2 | Prostaglandin reductase 2; related to PTGR1 | Potential 12-hydroxydehydrogenase |
| CYP4F3 | Cytochrome P450 4F3; omega-oxidation of LTB4 | Alternative LTB4 inactivation pathway |
| CYP4F2 | Cytochrome P450 4F2; omega-oxidation of LTB4 | Contributes to LTB4 clearance |
| GGT1 | Gamma-glutamyltransferase 1; may process cysteinyl leukotrienes | Indirect role in eicosanoid metabolism |
| DPEP1 | Dipeptidase 1; involved in leukotriene D4 metabolism | Related to cysteinyl leukotriene pathway |
| MGST2 | Microsomal glutathione S-transferase 2; leukotriene C4 synthesis | Upstream of LTB4 pathway |
| LTC4S | Leukotriene C4 synthase; branches from LTA4 | Determines cysteinyl leukotriene production |
How Is leukotriene B4 12-hydroxy dehydrogenase activity Regulated?
The activity of enzymes catalyzing GO:0097257 is regulated at multiple levels. Transcriptional regulation of PTGR1 and related genes can be influenced by inflammatory mediators and oxidative stress. Post-translational modifications and cellular redox status may affect enzyme activity, as NADP+ availability is tied to the pentose phosphate pathway. Additionally, substrate availability of LTB4, which is controlled by upstream enzymes such as ALOX5 and LTA4H, determines flux through this reaction. Inhibitor studies have shown that small molecules can modulate PTGR1 activity, suggesting pharmacological regulation is possible. In macrophages, LTB4 itself can modulate P2X7 receptor-mediated responses, indicating feedback regulation.
leukotriene B4 12-hydroxy dehydrogenase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PTGR1 | Inflammation and cancer chemoresistance | PTGR1 knockout cell lines and xenografts |
| LTB4R2 (BLT2) | Vascular degeneration and angiogenesis | BLT2 knockout mice and endothelial cell assays |
| LTB4R (BLT1) | Neutrophil chemotaxis and inflammatory diseases | BLT1 knockout mice in inflammation models |
| P2X7R | Leishmania infection and macrophage function | P2X7R knockout macrophages with LTB4 treatment |
| ALOX5 | Asthma and inflammatory disorders | ALOX5 knockout mice and airway inflammation models |
Inflammatory and infectious diseases
LTB4 is a potent chemoattractant for neutrophils, and its inactivation by GO:0097257 is crucial to resolve inflammation. In Leishmania amazonensis infection, LTB4 modulates P2X7 receptor-mediated elimination of the parasite in murine macrophages, suggesting that dysregulated LTB4 metabolism may impair host defense. Therefore, altered 12-hydroxy dehydrogenase activity could contribute to chronic infections and inflammatory pathology.
Vascular degeneration and dissection
The BLT2 receptor, which binds LTB4 and related metabolites such as 12-HETE, has been implicated in vascular degeneration, dissection, and rupture. 12-HETE acts as an endogenous modulator of BLT2, triggering vascular pathology. Since GO:0097257 generates 12-oxo-LTB4, which may also interact with BLT2, this activity could influence vascular smooth muscle and endothelial function, linking lipid metabolism to aortic diseases.
Angiogenesis and cancer
BLT2 activation by LTB4 promotes VEGF-induced angiogenesis. By controlling LTB4 levels, GO:0097257 may indirectly regulate tumor angiogenesis and cancer progression. Furthermore, PTGR1, an enzyme with this activity, has been studied for its role in drug metabolism and cancer chemoresistance, suggesting that targeting this activity could sensitize tumors to therapy.
From leukotriene B4 12-hydroxy dehydrogenase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does PTGR1 knockout increase LTB4 levels? | PTGR1 knockout cell lines (e.g., HEK293, macrophages) |
| Does a point mutation in the catalytic site abolish 12-hydroxy dehydrogenase activity? | Point-mutation knock-in of PTGR1 (e.g., catalytic residue mutation) |
| Can tagged PTGR1 be used to track subcellular localization? | Knock-in of FLAG- or GFP-tagged PTGR1 |
| Does overexpression of PTGR1 reduce LTB4-induced chemotaxis? | PTGR1 overexpression in neutrophil-like cells |
| Which genes regulate LTB4 metabolism? | CRISPR library screening in macrophage cell lines |
| Does BLT2 mediate 12-oxo-LTB4 effects in vascular cells? | BLT2 knockout vascular smooth muscle cells |
How to Study the leukotriene B4 12-hydroxy dehydrogenase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| LC-MS/MS lipidomics | LTB4 and 12-oxo-LTB4 levels | Quantify enzyme activity in cells |
| NADPH absorbance assay | NADPH production at 340 nm | Measure purified enzyme kinetics |
| CRISPR knockout screening | Gene essentiality for LTB4 metabolism | Identify regulators of GO:0097257 |
| RNA-seq | Transcript levels of PTGR1 and related genes | Assess expression changes in inflammation |
| Western blot | Protein expression of PTGR1 | Validate knockout or overexpression |
| Immunofluorescence | Subcellular localization of tagged PTGR1 | Determine organelle distribution |
| Chemotaxis assay | Neutrophil migration toward LTB4 | Functional readout of LTB4 inactivation |
| Site-directed mutagenesis | Enzyme activity of mutant PTGR1 | Identify catalytic residues |
Enzymatic activity assays
Direct measurement of GO:0097257 can be performed using purified enzymes or cell lysates by monitoring the conversion of LTB4 to 12-oxo-LTB4 via HPLC or LC-MS/MS. NADPH production can be followed spectrophotometrically at 340 nm. Such assays are essential to validate enzyme specificity and kinetics, as demonstrated for PTGR1.
Lipidomics and metabolomics
LC-MS/MS-based lipidomics allows quantification of LTB4 and its metabolites, including 12-oxo-LTB4, in biological samples. This approach can reveal changes in flux through GO:0097257 in response to genetic or pharmacological perturbations.
CRISPR-based genetic screens
Genome-wide CRISPR knockout screens can identify genes that regulate LTB4 levels or 12-hydroxy dehydrogenase activity. For example, screening in macrophages treated with LTB4 or infected with Leishmania could uncover modifiers of this pathway.
Transcriptomics and proteomics
RNA-seq and proteomics can assess expression changes in PTGR1 and related enzymes under inflammatory conditions. These methods help link GO:0097257 to broader transcriptional programs in immune cells.
How CRISPR Can Be Used to Study GO:0097257 leukotriene B4 12-hydroxy dehydrogenase activity
Knockout
CRISPR knockout of PTGR1 or other candidate genes can abolish 12-hydroxy dehydrogenase activity, leading to elevated LTB4 levels and enhanced neutrophil chemotaxis. Such models are valuable to establish causality between GO:0097257 and inflammatory phenotypes.
Point Mutation
Introducing point mutations in the catalytic site of PTGR1 (e.g., mutating a conserved tyrosine) can selectively eliminate dehydrogenase activity without affecting protein stability. These models help dissect the enzymatic versus non-enzymatic functions of the protein.
Knock-in
Knock-in of epitope tags (e.g., FLAG, HA) or fluorescent proteins (e.g., GFP) at the endogenous PTGR1 locus allows real-time tracking of enzyme localization and interaction partners. This approach preserves endogenous regulation and is ideal for imaging studies.
Overexpression
Overexpression of PTGR1 or other enzymes with GO:0097257 activity can reduce LTB4 levels and dampen inflammatory responses. Such models are useful to test whether increasing enzyme activity is protective in disease models.
How EDITGENE Supports leukotriene B4 12-hydroxy dehydrogenase activity Research
Researchers studying leukotriene B4 12-hydroxy dehydrogenase activity-related genes often need to determine whether a candidate gene is causally involved in lipid mediator metabolism, inflammation, or vascular disease. EDITGENE provides a comprehensive suite of CRISPR services to generate precisely engineered cell models, enabling rigorous functional validation of GO:0097257 and its associated pathways.
Contact EDITGENE today to design your custom CRISPR model for leukotriene B4 12-hydroxy dehydrogenase activity research.
Frequently Asked Questions About leukotriene B4 12-hydroxy dehydrogenase activity
What is leukotriene B4 12-hydroxy dehydrogenase activity?
It is the enzymatic activity defined by GO:0097257 that catalyzes the NADP+-dependent oxidation of leukotriene B4 to 12-oxo-leukotriene B4, thereby inactivating LTB4.
What genes are involved in leukotriene B4 12-hydroxy dehydrogenase activity?
PTGR1 is a well-characterized enzyme with this activity, and other potential candidates include CBR1 and AKR1C family members.
What is the reaction catalyzed by GO:0097257?
The reaction is: leukotriene B4 + NADP+ = 12-oxo-leukotriene B4 + NADPH + H+.
How is leukotriene B4 12-hydroxy dehydrogenase activity measured?
It can be measured by LC-MS/MS quantification of 12-oxo-LTB4 or by spectrophotometric monitoring of NADPH production at 340 nm.
What diseases are associated with leukotriene B4 12-hydroxy dehydrogenase activity?
Altered activity may contribute to inflammatory diseases, vascular degeneration, and impaired host defense against pathogens such as Leishmania.
Which receptors respond to leukotriene B4 and its metabolites?
LTB4 signals through BLT1 and BLT2; 12-HETE and possibly 12-oxo-LTB4 can also activate BLT2.
Can CRISPR be used to study leukotriene B4 12-hydroxy dehydrogenase activity?
Yes, CRISPR knockout, point mutation, and overexpression models allow precise manipulation of PTGR1 and related genes to study their function.
What is the role of PTGR1 in LTB4 metabolism?
PTGR1 exhibits 12-hydroxydehydrogenase activity toward LTB4, converting it to 12-oxo-LTB4 and reducing NADP+ to NADPH.
How does LTB4 12-hydroxy dehydrogenase activity affect inflammation?
By inactivating LTB4, this activity limits neutrophil chemotaxis and helps resolve inflammation.
What model systems are used to study GO:0097257?
Common models include PTGR1 knockout cell lines, BLT2 knockout mice, and lipidomics assays in macrophages and neutrophils.
Conclusion
GO:0097257, leukotriene B4 12-hydroxy dehydrogenase activity, is a critical enzymatic step that controls the inactivation of the potent lipid mediator LTB4. Through its product 12-oxo-LTB4 and its impact on BLT2 signaling, this activity influences inflammation, angiogenesis, and vascular stability. Dysregulation of this pathway has been linked to infectious and inflammatory diseases, making it an attractive target for therapeutic intervention. Advances in CRISPR-based genome editing and lipidomics now enable researchers to dissect the precise roles of enzymes like PTGR1 in health and disease. EDITGENE provides the tools and expertise to accelerate these discoveries.
References
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- 3. Mesa J et al.. 2015. Human prostaglandin reductase 1 (PGR1): Substrate specificity, inhibitor analysis and site-directed mutagenesis.. Chem Biol Interact 234:105-13 PMID: 25619643
- 4. Dahinden CA et al.. 1984. Stereospecificity of leukotriene B4 and structure-function relationships for chemotaxis of human neutrophils.. J Immunol 133(3):1477-82 PMID: 6086758
- 5. Chaves MM et al.. 2014. Leukotriene B4 modulates P2X7 receptor-mediated Leishmania amazonensis elimination in murine macrophages.. J Immunol 192(10):4765-73 PMID: 24729618
- 6. Kim GY et al.. 2009. Role of the low-affinity leukotriene B4 receptor BLT2 in VEGF-induced angiogenesis.. Arterioscler Thromb Vasc Biol 29(6):915-20 PMID: 19286633
