GO:1903268 positive regulation of ornithine catabolic process: Polyamine Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1903268 describes any process that activates or increases the frequency, rate or extent of ornithine catabolic process, a key node in polyamine metabolism [1, 5, 8].
• Ornithine catabolism feeds the polyamine pathway, producing putrescine and downstream spermidine and spermine that support cell growth and stress responses [1, 8].
• Positive regulation of ornithine catabolism intersects with ferroptosis amplification, macrophage pyroptosis, and colorectal cancer growth [1, 2, 6].
• Key enzymes include ODC1, ARG1, SAT1, and PAOX, whose activities determine flux from ornithine toward polyamines or back to glutamate [5, 7, 8].
• Dysregulated ornithine catabolism is linked to cancer, inflammation, and metabolic stress, making it a targetable vulnerability [1, 2, 6].
• CRISPR knockout, point mutation, knock-in, and overexpression models enable causal dissection of GO:1903268-related genes in disease contexts [1, 6, 7].
Description
GO:1903268, positive regulation of ornithine catabolic process, is a biological process ontology term that captures any molecular event that activates or increases the frequency, rate or extent of ornithine breakdown [1, 5]. Ornithine sits at a metabolic branch point: it can be converted to polyamines, to glutamate, or to other intermediates, and its catabolism is tightly linked to cellular growth, stress adaptation, and immune regulation [5, 8]. Understanding how this process is positively regulated is therefore central to fields ranging from cancer metabolism to inflammation and host-pathogen interactions [1, 2, 6].
positive regulation of ornithine catabolic process At A Glance
| GO ID | GO:1903268 |
|---|---|
| GO term | positive regulation of ornithine catabolic process |
| Ontology | biological_process |
| Synonym | activation of ornithine catabolism; upregulation of ornithine degradation; positive regulation of ornithine breakdown |
| Major function | Increases the rate of ornithine breakdown, often channeling ornithine into polyamine biosynthesis or glutamate production [1, 5, 8] |
| Related metabolites | Ornithine, putrescine, spermidine, spermine, glutamate [1, 8] |
| Key enzymes | ODC1, ARG1, SAT1, PAOX [5, 7, 8] |
| Disease relevance | Cancer, inflammation, metabolic stress, ferroptosis [1, 2, 6] |
What Is GO:1903268?
In my own words, GO:1903268 refers to any biological process that activates or increases the frequency, rate or extent of ornithine catabolic process, meaning the breakdown of ornithine into downstream metabolites such as putrescine, glutamate, or related intermediates [1, 5, 8]. This term is a positive regulatory node, so it encompasses upstream signals, enzyme modifications, and transcriptional programs that enhance ornithine catabolism rather than the catabolic reactions themselves [5, 8].
Why Is positive regulation of ornithine catabolic process Important in Cell Biology?
Positive regulation of ornithine catabolic process is important because it controls the flux of ornithine into polyamines and other metabolites that influence cell proliferation, immune cell function, and stress responses [1, 2, 8]. Dysregulation of this process can amplify ferroptosis in cancer cells, modulate macrophage pyroptosis during intestinal inflammation, and affect colorectal cancer growth through polyamine and eIF5A hypusination pathways [1, 2, 6]. Thus, understanding GO:1903268 provides mechanistic insight into metabolic vulnerabilities and potential therapeutic targets [1, 6].
• Controls polyamine biosynthesis, which is essential for cell growth and differentiation [1, 8].
• Links ornithine catabolism to ferroptosis amplification in cancer.
• Modulates macrophage pyroptosis and intestinal inflammation through polyamine regulation.
• Affects colorectal cancer growth via polyamine metabolism and eIF5A hypusination.
• Influences T cell responses and lung pathology during influenza infection through arginase 1 activity.
• Provides a metabolic branch point between polyamine and glutamate pathways [5, 8].
• Represents a targetable vulnerability in cancers with altered polyamine metabolism [1, 6].
• Relevant to host-pathogen interactions and environmental toxicity in aquatic organisms.
• Connects to acetylpolyamine metabolism and polyamine acetylation functions.
• Offers opportunities for CRISPR-based functional genomics of metabolic regulation [1, 6, 7].
What Happens During positive regulation of ornithine catabolic process?
Ornithine availability and transport
In simple terms: First, ornithine must be available in the right cellular compartment for breakdown to occur.
Ornithine is generated from arginine by arginase 1 (ARG1) or from glutamate semialdehyde, and its catabolism begins when it is available to enzymes such as ornithine decarboxylase (ODC1) [5, 7, 8]. Positive regulation of this process can involve increasing ornithine supply or enhancing its transport to sites of catabolism [5, 8].
Activation of ODC1 and polyamine synthesis
In simple terms: The main switch is turning on ODC1, which converts ornithine into putrescine, the first polyamine.
ODC1 catalyzes the decarboxylation of ornithine to putrescine, a rate-limiting step in polyamine biosynthesis [1, 8]. Positive regulation of ornithine catabolic process often involves upregulating ODC1 activity or expression, which channels ornithine into polyamine production and supports cell growth [1, 6, 8].
Polyamine acetylation and back-conversion
In simple terms: Polyamines can be acetylated and converted back, which helps regulate the pathway.
Spermidine and spermine can be acetylated by SAT1 and oxidized by PAOX, leading to back-conversion to putrescine or spermidine and influencing ornithine catabolic flux [5, 8]. This acetylation step is a key regulatory node that can modulate the overall rate of ornithine catabolism.
Integration with ferroptosis and stress responses
In simple terms: When polyamine metabolism is boosted, it can amplify ferroptosis, a form of cell death.
Polyamine-mediated ferroptosis amplification acts as a targetable vulnerability in cancer, linking positive regulation of ornithine catabolism to oxidative stress and cell death pathways. This integration highlights how metabolic flux from ornithine can determine cell fate under stress.
Immune and inflammatory signaling
In simple terms: Ornithine catabolism also affects immune cells and inflammation.
Aryl hydrocarbon receptor signaling confers protection against macrophage pyroptosis and intestinal inflammation by regulating polyamine biosynthesis, which is downstream of ornithine catabolism. Loss of CD4+ T cell-intrinsic arginase 1 accelerates Th1 response kinetics and reduces lung pathology during influenza infection, further linking ornithine metabolism to immune regulation.
Key Genes Involved in GO:1903268 positive regulation of ornithine catabolic process
The following genes and proteins are central to the regulation and execution of ornithine catabolic process and its positive regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ODC1 | Converts ornithine to putrescine, rate-limiting for polyamine synthesis [1, 8] | Target for cancer metabolism and ferroptosis studies |
| ARG1 | Produces ornithine from arginine, affecting substrate supply | Immune regulation and T cell responses |
| SAT1 | Acetylates polyamines, regulating back-conversion [5, 8] | Polyamine acetylation and stress responses |
| PAOX | Oxidizes acetylated polyamines, influencing flux [5, 8] | Polyamine catabolism and redox balance |
| SMOX | Oxidizes spermine, contributing to polyamine catabolism [5, 8] | Oxidative stress and cancer |
| AZIN1 | Antizyme inhibitor, regulates ODC1 stability | Polyamine homeostasis and cancer |
| OAZ1 | Antizyme, targets ODC1 for degradation | Feedback regulation of polyamine synthesis |
| eIF5A | Hypusination required for translation, linked to polyamine metabolism | Colorectal cancer growth and translation |
| AHR | Regulates polyamine biosynthesis and macrophage pyroptosis | Intestinal inflammation and immunity |
| MYC | Drives polyamine metabolism and translation | Cancer growth and metabolic reprogramming |
| CD4 | T cell marker, context for ARG1 studies | Influenza infection and lung pathology |
| GPX4 | Ferroptosis regulator, interacts with polyamine pathway | Cancer cell death and therapy |
| ACSL4 | Ferroptosis marker, linked to polyamine-mediated amplification | Ferroptosis research |
| SLC7A11 | Cystine transporter, affects ferroptosis and polyamine stress | Metabolic stress and cancer |
| NFE2L2 | Oxidative stress response, may intersect with polyamine metabolism | Redox regulation and cancer |
| HIF1A | Hypoxia response, may influence polyamine pathway | Tumor microenvironment |
| TP53 | Tumor suppressor, may modulate metabolic stress | Cancer metabolism and ferroptosis |
How Is positive regulation of ornithine catabolic process Regulated?
Positive regulation of ornithine catabolic process is controlled at multiple levels. ODC1 is regulated by antizyme (OAZ1) and antizyme inhibitor (AZIN1), which affect its stability and activity. Polyamine levels feedback to regulate ODC1 and SAT1, maintaining homeostasis [5, 8]. Signaling pathways such as AHR signaling can influence polyamine biosynthesis and macrophage pyroptosis. Additionally, MYC-driven transcription can upregulate polyamine metabolism genes, linking growth signals to ornithine catabolism. In immune cells, ARG1 activity modulates ornithine availability and T cell responses.
positive regulation of ornithine catabolic process and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ODC1 | Cancer, ferroptosis | Knockout and overexpression in cancer cell lines |
| ARG1 | Influenza infection, T cell responses | CD4+ T cell-specific knockout mice |
| SAT1 | Polyamine acetylation, stress | Point mutation and knockout cell models |
| AHR | Intestinal inflammation, macrophage pyroptosis | Macrophage-specific knockout |
| eIF5A | Colorectal cancer growth | Knock-in of hypusination-deficient mutant |
Cancer and ferroptosis
Polyamine-mediated ferroptosis amplification acts as a targetable vulnerability in cancer, where positive regulation of ornithine catabolism can increase polyamine levels and sensitize cells to ferroptosis. Combined inhibition of polyamine metabolism and eIF5A hypusination suppresses colorectal cancer growth through a converging effect on MYC translation, highlighting therapeutic potential.
Inflammation and immune regulation
Aryl hydrocarbon receptor confers protection against macrophage pyroptosis and intestinal inflammation through regulating polyamine biosynthesis, which is downstream of ornithine catabolism. Loss of CD4+ T cell-intrinsic arginase 1 accelerates Th1 response kinetics and reduces lung pathology during influenza infection, linking ornithine metabolism to immune responses.
Metabolic stress and toxicity
Microcystis aeruginosa-driven acute toxicity compromises immune-metabolic regulation and hepatocyte integrity in grass carp, indicating that environmental stressors can impact ornithine-related metabolic pathways. Serum albumin studies provide historical context for metabolic regulation in liver.
From positive regulation of ornithine catabolic process-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does ODC1 loss reduce ornithine catabolism and polyamine levels? | ODC1 knockout cell line [1, 8] |
| Does a point mutation in SAT1 alter polyamine acetylation? | SAT1 point-mutation knock-in |
| Can ARG1 overexpression enhance ornithine supply for catabolism? | ARG1 overexpression in T cells |
| Does tagged ODC1 reveal localization dynamics? | Tagged knock-in of ODC1 |
| Does AHR regulate polyamine biosynthesis in macrophages? | AHR knockout macrophages |
| Can CRISPR library screening identify regulators of ornithine catabolism? | Genome-wide CRISPR knockout library [1, 6] |
How to Study the positive regulation of ornithine catabolic process Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Metabolomics | Levels of ornithine, polyamines, glutamate [1, 8] | Assessing pathway flux |
| RNA-seq | Gene expression changes [1, 6] | Identifying transcriptional regulators |
| Proteomics | Protein abundance and modifications [5, 6] | Detecting acetylation and hypusination |
| CRISPR knockout screen | Gene essentiality and pathway regulators [1, 6] | Discovering novel regulators |
| Isotope tracing | Metabolic flux from ornithine | Quantifying catabolic rates |
| Western blot | Protein levels of ODC1, SAT1, etc. [1, 8] | Validating expression changes |
| Immunofluorescence | Localization of enzymes | Subcellular distribution studies |
| Bioinformatics pathway analysis | Enrichment of metabolic pathways [1, 6] | Interpreting omics data |
Metabolomics and flux analysis
Metabolomics can quantify ornithine, putrescine, spermidine, and spermine to assess flux through ornithine catabolic process [1, 8]. Isotope tracing can measure the conversion of labeled ornithine to downstream polyamines.
Transcriptomics and RNA-seq
RNA-seq can reveal changes in expression of ODC1, SAT1, PAOX, and other genes upon perturbation of positive regulation of ornithine catabolism [1, 6]. This helps identify transcriptional programs linked to the process.
Proteomics and post-translational modifications
Proteomics can detect changes in enzyme abundance and modifications such as acetylation or hypusination that affect ornithine catabolism [5, 6]. eIF5A hypusination is a key readout.
CRISPR screening and functional genomics
CRISPR knockout screens can identify genes whose loss alters polyamine levels or ferroptosis sensitivity, uncovering regulators of ornithine catabolic process [1, 6]. Bioinformatics analysis integrates screen hits with metabolic pathways.
How CRISPR Can Be Used to Study GO:1903268 positive regulation of ornithine catabolic process
Knockout
CRISPR knockout of ODC1, SAT1, or PAOX can abolish or reduce ornithine catabolic flux, revealing their necessity in polyamine synthesis and ferroptosis [1, 5, 8]. Knockout of AHR in macrophages can test its role in polyamine biosynthesis and pyroptosis.
Point Mutation
Point mutations in SAT1 or ODC1 can dissect catalytic residues or regulatory phosphorylation sites, linking specific amino acids to ornithine catabolic activity [5, 8]. Such models help distinguish enzyme activity from scaffolding functions.
Knock-in
Knock-in of tagged ODC1 or SAT1 allows tracking of protein localization and interactions in live cells, providing insight into dynamic regulation of ornithine catabolism. Knock-in of hypusination-deficient eIF5A can test its role in colorectal cancer growth.
Overexpression
Overexpression of ARG1 or ODC1 can increase ornithine catabolic flux and polyamine levels, modeling cancer or immune cell states [1, 7]. This approach can identify sufficiency of a gene to drive the process.
How EDITGENE Supports positive regulation of ornithine catabolic process Research
Researchers studying positive regulation of ornithine catabolic process-related genes often need to determine whether a candidate gene is causally involved in the pathway or merely correlated with metabolic changes. EDITGENE provides CRISPR-based cell model services to enable such causal studies.
Contact EDITGENE today to design your custom CRISPR model for positive regulation of ornithine catabolic process research.
Frequently Asked Questions About positive regulation of ornithine catabolic process
What is GO:1903268?
GO:1903268 is the Gene Ontology term for positive regulation of ornithine catabolic process, meaning any process that activates or increases the breakdown of ornithine [1, 5].
What genes are involved in positive regulation of ornithine catabolic process?
Key genes include ODC1, ARG1, SAT1, PAOX, SMOX, AZIN1, OAZ1, and AHR, among others [1, 2, 5, 7, 8].
How is ornithine catabolism regulated?
It is regulated by antizyme (OAZ1), antizyme inhibitor (AZIN1), polyamine feedback, and signaling pathways such as AHR and MYC [2, 6, 8].
What diseases are linked to ornithine catabolic process?
Cancer, ferroptosis, intestinal inflammation, and influenza infection have been linked to ornithine catabolism and polyamine metabolism [1, 2, 6, 7].
What is the role of ODC1 in ornithine catabolism?
ODC1 converts ornithine to putrescine, a rate-limiting step in polyamine synthesis, and its activity is often upregulated in cancer [1, 8].
How can I study positive regulation of ornithine catabolic process?
Metabolomics, RNA-seq, proteomics, and CRISPR screens are common methods to study this process [1, 5, 6, 8].
What is the connection between polyamines and ferroptosis?
Polyamine-mediated ferroptosis amplification acts as a targetable vulnerability in cancer, linking ornithine catabolism to cell death.
Does AHR regulate polyamine biosynthesis?
Yes, AHR confers protection against macrophage pyroptosis and intestinal inflammation through regulating polyamine biosynthesis.
What is the role of ARG1 in immune cells?
Loss of CD4+ T cell-intrinsic arginase 1 accelerates Th1 response kinetics and reduces lung pathology during influenza infection.
Can CRISPR be used to study ornithine catabolism?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models enable causal studies of genes in this pathway [1, 5, 6, 7, 8].
Conclusion
GO:1903268, positive regulation of ornithine catabolic process, is a critical metabolic regulatory node that influences polyamine biosynthesis, ferroptosis, immune responses, and cancer growth [1, 2, 6, 7]. Understanding its regulation provides insights into metabolic vulnerabilities and potential therapeutic targets [1, 6]. CRISPR-based models and multi-omics approaches are essential tools for dissecting this process and translating findings into disease interventions [1, 5, 6, 8].
References
- 1. Bi G et al.. 2024. Polyamine-mediated ferroptosis amplification acts as a targetable vulnerability in cancer.. Nat Commun 15(1):2461 PMID: 38504107
- 2. Gao Y et al.. 2024. Aryl hydrocarbon receptor confers protection against macrophage pyroptosis and intestinal inflammation through regulating polyamine biosynthesis.. Theranostics 14(11):4218-4239 PMID: 39113799
- 3. Rothschild MA et al.. 1988. Serum albumin.. Hepatology 8(2):385-401 PMID: 3281888
- 4. Ma L et al.. 2026. Microcystis aeruginosa-driven acute toxicity compromises immune-metabolic regulation and hepatocyte integrity in grass carp.. Environ Pollut 398:128088 PMID: 41956314
- 5. Seiler N. 1987. Functions of polyamine acetylation.. Can J Physiol Pharmacol 65(10):2024-35 PMID: 3322538
- 6. Coni S et al.. 2023. Combined inhibition of polyamine metabolism and eIF5A hypusination suppresses colorectal cancer growth through a converging effect on MYC translation.. Cancer Lett 559:216120 PMID: 36893894
- 7. West EE et al.. 2023. Loss of CD4(+) T cell-intrinsic arginase 1 accelerates Th1 response kinetics and reduces lung pathology during influenza infection.. Immunity 56(9):2036-2053.e12 PMID: 37572656
- 8. Bae DH et al.. 2018. The old and new biochemistry of polyamines.. Biochim Biophys Acta Gen Subj 1862(9):2053-2068 PMID: 29890242
