IL 1RA Mouse
Description
Introduction to IL-1RA Mouse
Interleukin-1 Receptor Antagonist (IL-1RA) in mice is a critical regulatory protein that competitively inhibits the pro-inflammatory cytokines IL-1α and IL-1β by binding to IL-1 receptors without activating downstream signaling . This 17–25 kDa glycoprotein is encoded by the Il1rn gene on chromosome 2 and exists in multiple isoforms, including secreted (sIL-1Ra) and intracellular forms (icIL-1Ra1-3) . Its primary role is to modulate inflammatory responses, making it essential for studying immune regulation and therapeutic interventions .
Genetic and Expression Profiles
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Expression Sites: Keratinocytes, myeloid cells, hepatocytes, and endothelial cells .
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Regulation: Induced by TLR/STING agonists, LPS, and inflammatory stimuli .
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Strain Variability: Balb/c and DBA/1 mice show differential disease susceptibility in Il1rn −/− models .
Inflammatory Regulation
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IL-1 Inhibition: Blocks IL-1α/β binding to IL-1R1, preventing NF-κB activation .
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Homeostatic Role: Constitutively high IL-1ra levels in wild-type mice suppress systemic inflammation triggered by RNA-LPX, LPS, or STING agonists .
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Skin-Specific Activity: Keratinocyte-derived icIL-1Ra1 mitigates psoriasis-like inflammation by antagonizing IL-1α .
Adaptive Mechanisms in Il1rn −/− Mice
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Compensatory Shedding: Loss of IL-1ra leads to increased soluble IL-1R1 release, acting as a decoy receptor .
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Cytokine Storm Susceptibility: Uncontrolled IL-1 signaling in knockout mice results in hypothermia and elevated serum cytokines (e.g., TNF-α, IL-6) .
Recombinant IL-1RA
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Production: Expressed in E. coli; used for in vitro and in vivo studies to mimic endogenous inhibition .
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Therapeutic Testing: Reduces severity in autoimmune encephalomyelitis (EAMG) and seizure models .
Detection Tools
Disease Models
Strain-Specific Phenotypes
| Strain | Il1rn −/− Phenotype | Mechanism | Source |
|---|---|---|---|
| Balb/c | Arthritis susceptibility | Elevated IL-1β in bone marrow | |
| DBA/1 | Arthritis resistance | Unchanged IL-1R1 expression |
Comparative Analysis: Mouse vs. Human IL-1RA
| Feature | Mouse IL-1RA | Human IL-1RA |
|---|---|---|
| Receptor Binding | Binds IL-1R1 only (IL-1R2 non-functional) | Binds IL-1R1 and IL-1R2 |
| Glycosylation | Single N-linked site | Multiple sites; higher molecular weight |
| Intracellular Isoforms | icIL-1Ra1 confirmed; icIL-1Ra2/3 not observed | Three isoforms (icIL-1Ra1-3) |
| Therapeutic Use | Preclinical models only | FDA-approved (Anakinra) for rheumatoid arthritis |
Therapeutic Potential
Product Specs
Q&A
What is IL-1RA and how does it function in the inflammatory response?
IL-1RA is an endogenous inhibitor of IL-1 activity that competes with IL-1α and IL-1β for binding to the IL-1 receptor (IL-1R). It acts as a natural brake on inflammation by preventing IL-1-mediated signaling without triggering downstream inflammatory cascades. In normal physiological conditions, IL-1RA helps maintain homeostasis within the IL-1 signaling network. The balance between IL-1 cytokines and IL-1RA is critical for proper immune function, and disruption of this balance can lead to pathological inflammatory states .
Methodology note: When studying IL-1RA function, researchers should consider both local tissue concentrations and systemic levels, as these may have different physiological impacts. Quantification should employ high-sensitivity ELISA or multiplexed cytokine assays to accurately measure the IL-1/IL-1RA ratio.
What are the principal phenotypes of IL-1RA-deficient mice?
IL-1RA-deficient (Il1rn−/−) mice demonstrate several distinctive phenotypes:
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Spontaneous development of autoimmune arthritis in an IL-17- and T-cell-dependent manner
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Increased expression of inflammatory mediators
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Accelerated intervertebral disc degeneration
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Altered susceptibility to seizures
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Modified insulin sensitivity and metabolic regulation
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Differential inflammatory responses to tissue injury
The severity and onset of these phenotypes are significantly influenced by genetic background, with strain-dependent variations in disease manifestation .
What mouse strains are commonly used for IL-1RA research?
| Mouse Strain | Phenotypic Characteristics | Research Applications |
|---|---|---|
| C57BL/6J Il1rn−/− | Moderate arthritis development, less severe IVD degeneration | General inflammatory studies, neurological research |
| BALB/c Il1rn−/− | More severe arthritis, pronounced IVD degeneration | Autoimmunity models, musculoskeletal research |
Strain background critically influences disease manifestation, with major quantitative trait loci (QTLs) regulating susceptibility to spontaneous inflammatory arthritis and other phenotypes in IL-1RA-deficient mice .
Methodology note: Researchers should always report the complete genetic background of IL-1RA mouse models and consider potential backcrossing effects when interpreting results.
What are the molecular mechanisms driving autoimmune arthritis in IL-1RA-deficient mice?
The pathogenesis of arthritis in Il1rn−/− mice involves several interconnected mechanisms:
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Excessive IL-1 signaling due to lack of endogenous inhibition
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γδ T cells (particularly Vγ6+ subset) become major producers of IL-17 in the joints
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Recruitment of CCR2+ γδ T cells to joints via CCL2 induction by CD4+ T cells
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Intrinsically high IL-1R expression on Vγ6+ cells due to loss of IL-1R downregulation by IL-1RA
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Synergistic activation by IL-1β and IL-23 required for optimal IL-17 production
These Il1rn−/− mice provide valuable insights into the IL-17/IL-1 axis in inflammatory arthritis, with γδ T cells representing a critical cellular source of pathogenic IL-17 .
How does IL-1RA deficiency affect tissue-specific inflammatory responses?
IL-1RA deficiency impacts different tissues in distinct ways:
Methodology note: When analyzing tissue-specific effects, researchers should combine histopathological assessment, functional testing, and molecular analyses (gene/protein expression) for comprehensive evaluation.
What experimental considerations are critical when designing studies with IL-1RA-deficient mice?
When working with IL-1RA mouse models, researchers should consider:
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Age-dependent phenotypes: IL-1RA-deficient mice show age-dependent changes. For example, intervertebral disc histopathology significantly worsens at 3 months but differences diminish by 12 months compared to wild-type controls .
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Stimulation protocols: γδ T cells from Il1rn−/− mice respond differently to stimulation. GFP expression (reflecting IL-17 production) is detectable without stimulation in joints, while phorbol myristate acetate and ionomycin stimulation may be required for detection in other tissues .
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Gene expression dynamics: IL-1RA deficiency leads to paradoxical downregulation of inflammatory genes in some tissues and time points, reflecting complex compensatory mechanisms .
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Strain-specific effects: Experimental design must account for significant strain-dependent variations in phenotype manifestation .
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Control selection: Using both wild-type and heterozygous littermates as controls helps distinguish gene dosage effects.
How do IL-1RA-deficient mice respond to inflammatory challenges compared to wild-type mice?
IL-1RA-deficient mice exhibit distinctive responses to various inflammatory challenges:
What potential therapeutic interventions have been validated using IL-1RA mouse models?
Several therapeutic approaches have been validated in IL-1RA-deficient mouse models:
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Recombinant IL-1Ra (anakinra): Administration of anakinra can rescue disease phenotypes in mice with genetic deficiency of NLRC4 or IL-1Ra, confirming specific therapeutic efficacy .
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HSPC-mediated IL-1RA delivery: Lentivirus-mediated gene transfer with hematopoietic stem/progenitor cells (HSPCs) delivers IL-1RA systemically, preventing IL-1–mediated inflammation in murine models of neutrophil-mediated inflammation, cryopyrin-associated periodic syndrome, and experimental autoimmune encephalitis .
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IL-1Ra normalization in metabolic disease: In obese mouse models, normalization of plasma IL-1Ra concentration improves insulin sensitivity through decreased liver inflammation, suggesting potential applications in metabolic disorders .
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Targeted anti-inflammatory approaches: Studies with IL-1RA-deficient mice have identified downstream inflammatory mediators that may serve as additional therapeutic targets for specific conditions.
How do IL-1RA-deficient mice serve as models for human diseases?
IL-1RA-deficient mice model several human pathologies:
These models provide insights into pathogenic mechanisms and potential therapeutic approaches for corresponding human conditions.
What are the optimal techniques for phenotyping IL-1RA-deficient mice?
Comprehensive phenotyping of IL-1RA-deficient mice requires multiple complementary approaches:
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Histopathological assessment: Tissue-specific scoring systems should be employed (e.g., for arthritis, intervertebral disc degeneration).
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Functional testing: Biomechanical testing for joints and intervertebral discs, seizure threshold testing for neurological phenotypes, and metabolic testing for insulin sensitivity.
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Flow cytometry: For immune cell profiling, particularly assessing IL-17-producing cells. GFP reporter systems (e.g., Il1rn−/−Il17a^GFP/GFP^ mice) enable detection of IL-17-expressing cells without stimulation .
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Gene expression analysis: qPCR for inflammatory, anabolic, and catabolic genes reveals complex compensatory mechanisms in different tissues .
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Cytokine profiling: Multiplex analysis of inflammatory mediators in serum and tissue lysates to characterize the inflammatory milieu.
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Imaging: Micro-CT for bone erosions, MRI for soft tissue pathology.
How can contradictory data in IL-1RA mouse studies be reconciled?
Research with IL-1RA-deficient mice sometimes yields seemingly contradictory results. Key approaches to resolving these include:
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Strain background analysis: Differences between C57BL/6J and BALB/c IL-1RA-deficient mice may explain divergent findings .
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Age-dependent effects: The phenotype changes with age; intervertebral disc histopathology shows significant strain differences at 3 months but not at 12 months .
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Tissue-specific responses: Downregulation of inflammatory genes in some tissues despite increased inflammation in others reflects complex compensatory mechanisms .
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Molecular pathway analysis: IL-1RA deficiency can affect multiple pathways beyond direct IL-1 signaling, including IL-1R-independent mechanisms .
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Context-dependent effects: IL-1RA may have different impacts depending on the inflammatory context and concurrent stimuli.
What are the best experimental designs for studying disease progression in IL-1RA-deficient mice?
Optimal experimental designs include:
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Longitudinal studies: Serial assessment of the same animals over time using non-terminal methods (e.g., imaging, behavioral testing, blood sampling).
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Cross-sectional time-course studies: Analyzing cohorts at different ages (e.g., 3, 6, 9, 12 months) to capture age-dependent progression.
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Challenge models: Applying standardized inflammatory challenges or injury models to assess response dynamics.
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Intervention timing studies: Administering therapeutic agents at different disease stages to determine optimal intervention windows.
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Reporter systems: Using reporter mice (e.g., Il1rn−/−Il17a^GFP/GFP^) to track cytokine-producing cells in real-time .
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Multi-tissue analysis: Examining multiple organ systems simultaneously to capture systemic effects and tissue interactions.
How can single-cell technologies enhance our understanding of IL-1RA deficiency effects?
Single-cell approaches offer new opportunities to dissect cellular heterogeneity in IL-1RA-deficient mouse tissues:
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scRNA-seq: Identifying distinct cellular subpopulations and their transcriptional responses to IL-1RA deficiency, especially within T cell populations.
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CyTOF/spectral flow cytometry: High-dimensional characterization of immune cell populations in various tissues.
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Spatial transcriptomics: Mapping inflammatory cell distributions within affected tissues to understand microenvironmental influences.
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Lineage tracing: Determining the developmental origin of pathogenic IL-17-producing cells in IL-1RA-deficient mice.
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Clonal analysis: Assessing T cell receptor repertoire changes in response to chronic IL-1 signaling.
What gene-environment interactions modulate the phenotype of IL-1RA-deficient mice?
Several environmental factors may influence IL-1RA-deficient mouse phenotypes:
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Microbiome composition: Gut microbiota influences systemic inflammation and may modulate arthritis severity.
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Diet: Metabolic changes induced by different diets could alter inflammatory responses.
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Housing conditions: Pathogen status of animal facilities may impact disease manifestation.
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Physical activity: Movement and mechanical loading may affect joint and intervertebral disc phenotypes.
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Stress: Psychological stress can alter immune function through neuroendocrine pathways.
Systematic assessment of these factors could help explain variability in research findings and identify additional therapeutic targets.
How can IL-1RA mouse models be integrated with human data to advance translational research?
Bridging mouse models and human disease requires several approaches:
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Comparative transcriptomics: Analyzing shared gene expression signatures between IL-1RA-deficient mouse tissues and human disease samples.
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Humanized mouse models: Introducing human immune cells into IL-1RA-deficient mice to study species-specific responses.
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Patient-derived xenografts: Testing patient samples in IL-1RA-deficient backgrounds to personalize therapeutic approaches.
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Validation in human genetics: Correlating findings from IL-1RA-deficient mice with human IL1RN polymorphisms or mutations.
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Drug screening platforms: Using IL-1RA-deficient mice to validate therapeutic candidates identified from human studies.
These integrative approaches can accelerate translation of findings from IL-1RA mouse models to clinical applications.
Product Science Overview
Interleukin-1 Receptor Antagonist (IL-1Ra) is a naturally occurring protein that plays a crucial role in regulating the immune response. It is part of the interleukin-1 (IL-1) family of cytokines, which are involved in the initiation and regulation of inflammatory responses. The recombinant form of IL-1Ra, specifically derived from mice, has been extensively studied for its therapeutic potential in various inflammatory diseases.
IL-1Ra was first discovered in 1984 in the urine and serum of patients with leukemia and in the supernatant of cultured monocytes . The protein was named for its ability to competitively bind to the IL-1 receptor, thereby antagonizing the function of IL-1, a potent pro-inflammatory cytokine.
The recombinant form of IL-1Ra, known as anakinra or Kineret™, was developed to mimic the natural antagonist. This recombinant protein differs from the native IL-1Ra by the addition of an N-terminal methionine . It binds to the IL-1 receptor type I with the same affinity as IL-1β, effectively inhibiting its pro-inflammatory effects.
IL-1Ra functions by binding to the IL-1 receptor without eliciting a signal, thereby blocking the binding of IL-1α and IL-1β. This competitive inhibition prevents the downstream signaling that leads to inflammation and tissue damage. By modulating the IL-1 signaling pathway, IL-1Ra helps to control excessive inflammatory responses that can lead to chronic inflammatory diseases .
Recombinant IL-1Ra has been investigated for its potential in treating various inflammatory conditions. One of the most well-studied applications is in the treatment of rheumatoid arthritis (RA). Clinical trials have demonstrated that anakinra, in combination with methotrexate, significantly reduces the signs and symptoms of RA in patients who have inadequate responses to methotrexate alone . The treatment is generally well-tolerated, with the most common side effect being mild to moderate injection site reactions.
In addition to RA, IL-1Ra has shown promise in treating other inflammatory diseases, including psoriasis, atopic dermatitis, and other skin disorders . Its ability to modulate the immune response makes it a valuable therapeutic agent in conditions where excessive inflammation is a key pathological feature.
Ongoing research continues to explore the potential of IL-1Ra in various disease contexts. Studies are investigating its role in other autoimmune and inflammatory diseases, as well as its potential in combination therapies. The development of new delivery methods and formulations aims to improve the efficacy and patient compliance of IL-1Ra treatments.
In conclusion, the recombinant form of Interleukin-1 Receptor Antagonist (Mouse) represents a significant advancement in the treatment of inflammatory diseases. Its ability to effectively inhibit IL-1 signaling and modulate the immune response holds great promise for future therapeutic applications.
