IL11RA Rat

What is the molecular structure and characteristics of IL11RA in rats?

IL11RA (also referred to as Il11ra1) in rats is a receptor for interleukin-11 that belongs to the hematopoietic cytokine receptor family. The rat IL11RA protein contains 356 amino acids (positions 24-371) with a molecular mass of 39.2 kDa, though it appears at 40-57 kDa on SDS-PAGE due to glycosylation . Structurally, it features an extracellular region with a two-domain structure composed of an immunoglobulin-like domain and a cytokine receptor-like domain . Like other species, rat IL11RA contains binding sites for IL-11 and functions through heterodimerization with the signaling moiety gp130 .

IL11RA is also known by several synonyms including Interleukin-11 receptor subunit alpha, IL-11 receptor subunit alpha, IL-11R subunit alpha, IL-11R-alpha, and Il11ra1 . The receptor is part of the IL6ST receptor system, which includes receptors for IL6, LIF, OSM, CNTF, IL11, and CT1, all utilizing IL6ST (gp130) for initiating signal transmission .

How does IL11RA function in signal transduction in rat models?

In rat models, IL11RA functions as the ligand-binding component of a heterodimeric receptor complex with gp130. The signaling mechanism involves:

• IL-11 binding to IL11RA

• Recruitment of gp130, forming an IL-11/IL11RA/gp130 complex

• Activation of multiple downstream pathways, primarily STAT3 and ERK signaling cascades

This signaling complex is involved in controlling proliferation and/or differentiation of skeletogenic progenitor cells and other mesenchymal cells . IL11RA-mediated signaling has been documented in 40 unique molecules involved in 18 protein-protein interactions, 26 enzyme-substrate reactions, 7 translocation events, and 4 activation/inhibition reactions .

The IL11/IL11RA/IL6ST complex has been implicated in various physiological and pathological processes, including hematopoiesis, fertility, inflammatory responses, and cancer metastasis .

What is the expression pattern of IL11RA in rat tissues?

IL11RA exhibits specific temporal and spatial expression patterns in rat tissues:

• Uterine tissue: IL11RA is expressed throughout both primary and secondary decidua during the peri-implantation period. Unlike IL-11 (which is upregulated at 5.5 days after mating), IL11RA expression remains relatively constant throughout the peri-implantation period .

• Skeletal muscle: Western blot analysis has confirmed expression of IL11RA in rat skeletal muscle tissue .

• Liver: Hepatic stellate cells, which have fibroblast-like functions and are major determinants of liver fibrosis, express IL11RA at baseline .

• Pancreas: Similar to liver, pancreatic stellate cells express IL11RA and both secrete and respond to IL-11 when stimulated with disease factors .

This expression pattern correlates with the diverse physiological functions of IL11RA signaling in various tissue systems, particularly in reproduction, inflammation, and tissue remodeling processes.

How important is IL11RA in rat fertility and reproduction?

IL11RA plays a critical role in rat fertility, particularly during implantation and decidualization. Research has established:

• IL11RA is expressed throughout primary and secondary decidua in the rat uterus during the peri-implantation period .

• While IL11RA expression remains relatively constant, its ligand IL-11 is upregulated in the rat uterus at the initiation of implantation (approximately 5.5 days after mating), with high expression in the primary decidual zone at the time of the attachment reaction .

• The conservation of temporal and spatial expression patterns of IL-11 and IL11RA in both rat and mouse uteri suggests evolutionary preservation of their functions in reproduction .

• Studies in mice have demonstrated that IL-11 signaling is required for female fertility, and in the absence of IL-11, decidualization is markedly retarded and implantation fails . The similar expression patterns in rats strongly suggest a comparable essential role in rat fertility .

This evidence collectively indicates that IL11RA-mediated signaling is a crucial component of successful implantation and early pregnancy in rats, making it an important target for reproductive biology research.

How does species-specificity affect IL11 and IL11RA interactions in experimental settings?

Species-specificity significantly impacts IL11 and IL11RA interactions in experimental settings, creating important considerations for researchers:

• Cross-species reactivity anomalies: Recombinant human IL-11 (rhIL11) binds strongly to mouse Il11ra1 but incompletely activates the resulting signaling complex, acting as a partial/incomplete agonist that blocks endogenous mouse Il11 signaling . This phenomenon creates a complex experimental situation where rhIL11 can function as an antagonist rather than an agonist.

• Contradictory experimental outcomes: This species-specificity explains discrepancies in research findings. For example, in acetaminophen-induced liver injury (AILI) models, rhIL11 appears protective in mice, while species-matched recombinant mouse IL-11 (rmIL11) is not protective . The therapeutic effect of rhIL11 was accompanied by a reduction in hepatic ERK and JNK activation .

• Non-receptor mediated effects: Surprisingly, rhIL11 can partially activate gp130 signaling in mouse cells lacking Il11ra1, suggesting more complex mechanisms beyond simple receptor binding .

• Implications for rat studies: Similar cross-species reactivity issues likely exist between human IL-11 and rat IL11RA, though these are less extensively documented . Researchers working with rat models should use species-matched rat IL-11 when studying physiological effects or carefully validate cross-species interactions.

This species-specificity explains why early literature (1995–2015) consistently reported rhIL11 as protective in mouse models, when these experiments were actually representing loss-of-function rather than gain-of-function experiments .

What role does IL11RA play in liver pathology and metastasis models?

IL11RA has significant roles in liver pathology and metastasis models:

• Liver Fibrosis and Inflammation:

  • IL11RA is expressed in hepatic stellate cells, which are major determinants of liver fibrosis

  • IL11 signals through IL11RA in these cells to activate STAT3 and ERK, inducing mesenchymal transitions leading to fibro-inflammatory liver diseases

  • Contradictory findings exist regarding IL11's role in liver damage: while earlier studies suggested IL11 was hepatoprotective, recent research indicates that it may be detrimental to hepatocyte function in some contexts of fibro-inflammatory liver disease

• Hepatic Metastasis:

  • IL11RA has been implicated in liver metastasis, particularly in skin cutaneous melanoma (SKCM)

  • IL11RA downregulation significantly inhibits migratory and invasive capabilities of melanoma cells in vitro

  • Il11ra gene knockout in mice demonstrates substantial reduction in hepatic melanoma metastasis, emphasizing IL11RA's pivotal role in driving metastatic behavior

• Molecular Mechanisms:

  • IL11RA influences the expression of matrix metalloproteinases, particularly decreasing MMP2 and increasing MMP8 expression

  • IL11RA correlates positively with STAT3 activation, and its inhibition leads to suppressed STAT3 pathway in liver tissue

  • The IL11/IL11RA complex regulates hepatic ERK and JNK activation, affecting liver injury responses

These findings suggest that targeting IL11RA may offer therapeutic potential for both fibro-inflammatory liver diseases and metastatic conditions affecting the liver .

What are the downstream pathways activated by IL11RA signaling in rats?

IL11RA signaling in rats activates several key downstream pathways:

These pathways make IL11RA signaling relevant to diverse physiological and pathological processes, including inflammation, fibrosis, metastasis, and tissue regeneration . The specific activation patterns may vary depending on cell type and physiological context.

How can IL11RA be targeted therapeutically in rat disease models?

IL11RA can be targeted therapeutically in rat disease models through several strategies:

• Receptor Neutralization:

  • Anti-IL11RA antibodies can block receptor function and inhibit IL-11 signaling

  • These antibodies prevent the formation of the IL-11/IL11RA/gp130 complex, thereby inhibiting downstream signaling cascades

• Genetic Approaches:

  • siRNA or shRNA can effectively knockdown Il11ra expression

  • CRISPR/Cas9-mediated targeting of Il11ra can generate knockout models

  • IL11RA downregulation has been shown to inhibit migratory and invasive capabilities of cancer cells in vitro

  • Il11ra gene knockout significantly reduces hepatic melanoma metastasis in vivo

• Ligand Modulation:

  • Recombinant soluble IL11RA can act as a decoy receptor, binding IL-11 in the extracellular space

  • Species-matched or cross-species recombinant IL-11 can be used to modulate IL11RA signaling, with careful consideration of species-specificity effects

• Downstream Pathway Inhibitors:

  • STAT3 inhibitors can block a major downstream effector of IL11RA signaling

  • ERK pathway inhibitors may attenuate IL11RA-mediated fibrotic and metastatic processes

Application in specific rat disease models:

• For liver fibrosis: Targeting IL11RA to reduce stellate cell activation and fibrotic progression

• For cancer metastasis: IL11RA inhibition to reduce hepatic metastasis of cancers like melanoma

• For reproductive disorders: Modulating IL11RA signaling to affect decidualization and implantation processes

When designing therapeutic interventions targeting IL11RA, researchers should consider the diverse physiological roles of IL11RA and potential effects on non-target tissues .

What are the optimal methods for detecting IL11RA expression in rat tissues?

Several complementary methods can be used for optimal detection of IL11RA expression in rat tissues:

For comprehensive analysis, researchers should consider combining multiple methods. For example, qRT-PCR provides quantitative expression data, while in situ hybridization or immunohistochemistry reveals spatial distribution patterns within tissues. Western blotting confirms protein expression and size, complementing the mRNA-based approaches .

What approaches are effective for IL11RA gene knockout or knockdown in rats?

Several approaches can be effectively used for IL11RA gene knockout or knockdown in rats:

• CRISPR/Cas9 Gene Editing:

  • Currently the most efficient approach for gene knockout in rats

  • Design guide RNAs (gRNAs) targeting specific regions of the Il11ra gene

  • Evidence: Il11ra gene knockout in mice demonstrated substantial reduction in hepatic melanoma metastasis, suggesting similar approaches would be effective in rats

  • Multiple gRNAs can be used for increased efficiency or to delete larger gene segments

  • CRISPR components can be delivered as plasmids, mRNA, or ribonucleoprotein complexes

• RNA Interference (RNAi):

  • siRNA or shRNA can effectively knockdown Il11ra expression

  • Evidence: IL11RA downregulation significantly inhibited migratory and invasive capabilities of cancer cells in vitro

  • Useful for transient reduction of IL11RA or for tissue-specific applications

  • Can be delivered via viral vectors for stable expression or transiently via lipid-based transfection

• Verification Protocols:

  • Genotyping: PCR-based methods to confirm genomic modifications

  • Expression analysis: Western blot using validated antibodies that detect rat IL11RA (e.g., MAB19771)

  • Functional assays: Assess IL-11 response in cells or tissues from knockout animals, including STAT3 phosphorylation status

• Phenotyping Considerations:

  • Fertility assessment: Based on IL11RA's important role in implantation

  • Metastasis models: Evaluate hepatic melanoma metastasis in IL11RA-deficient rats

  • Inflammation and fibrosis: Assess responses in liver and pancreatic injury models

When selecting an approach, researchers should consider factors such as efficiency, potential off-target effects, resources available, and the specific experimental requirements relevant to IL11RA biology.

What are the optimal experimental protocols for studying IL11RA signaling in rat cells?

Optimal experimental protocols for studying IL11RA signaling in rat cells include:

• Cell Isolation and Culture:

  • Target cells: Isolate primary rat cells that express IL11RA (e.g., decidual cells, hepatic stellate cells, skeletal muscle cells)

  • Culture conditions: DMEM or RPMI-1640 supplemented with 10% FBS, maintained at 37°C in 5% CO2

  • Serum starvation: Prior to stimulation experiments, serum-starve cells for 12-24 hours to reduce background signaling

• Stimulation Protocols:

  • Ligand selection: Use species-matched rat IL-11 for physiologically relevant signaling

  • Caution with recombinant human IL-11 as it may act as a partial agonist/antagonist in rat cells

  • Dose-response: Typically 1-100 ng/mL of IL-11, with 10 ng/mL commonly used

  • Time-course: 5-30 minutes for immediate signaling events; hours to days for gene expression changes

• Signaling Analysis:

  • Western blotting: For detecting phosphorylated STAT3, ERK, and JNK

  • Immunoprecipitation: To study complex formation between IL11RA and gp130

  • Reporter assays: Using STAT3-responsive luciferase constructs

• Functional Assays:

  • Migration assays: Wound healing or transwell assays

  • Invasion assays: Matrigel-coated transwell chambers

  • Proliferation assays: MTT, BrdU incorporation

  • Differentiation assays: For studying mesenchymal transitions in stellate cells

• Gene Expression Analysis:

  • qRT-PCR: For measuring changes in target gene expression

  • Focus on known IL11RA targets including MMPs (particularly MMP2 and MMP8)

  • RNA-seq: For genome-wide transcriptional responses to IL11RA signaling

These protocols should be adapted based on the specific rat cell type being studied and the particular aspect of IL11RA signaling under investigation. Researchers should include appropriate positive and negative controls and validate key findings with multiple methodological approaches .

How can researchers validate IL11RA antibodies for rat studies?

Validating IL11RA antibodies for rat studies requires a systematic approach to ensure specificity, sensitivity, and reproducibility:

• Western Blot Validation:

  • Test antibody on positive control samples known to express IL11RA (e.g., rat skeletal muscle)

  • Include negative controls (tissues with low/no IL11RA expression)

  • Verify the molecular weight (approximately 45-49 kDa for rat IL11RA as demonstrated with MAB19771)

  • Test under both reducing and non-reducing conditions if studying conformational epitopes

• Cross-Reactivity Assessment:

  • Evidence shows Mouse Anti-Human IL-11 Ra Monoclonal Antibody (MAB19771) detects IL11RA across human, mouse, and rat species

  • Test antibody against recombinant IL11RA proteins to determine specificity

  • Perform peptide competition assays to confirm epitope specificity

• Immunohistochemistry Validation:

  • Test antibody on fixed tissue sections with known IL11RA expression patterns

  • Compare staining patterns with published in situ hybridization data (e.g., decidual expression patterns)

  • Include appropriate isotype controls

• Functional Validation:

  • Test whether the antibody can neutralize IL-11 binding or IL11RA-mediated signaling

  • Assess effects on downstream pathways (e.g., STAT3 phosphorylation)

  • Determine if the antibody can reproduce known IL11RA inhibition phenotypes

• Alternative Detection Validation:

  • Cross-validate with Simple Western™ methodology

  • Compare results with mRNA expression data from qPCR or RNase protection assays

  • Use multiple antibodies targeting different epitopes of IL11RA when possible

Thorough antibody validation ensures reliability in IL11RA research and prevents misinterpretation of experimental results. Researchers should document all validation steps including antibody source, catalog number, experimental conditions, and controls used.

What are the critical considerations for recombinant IL11RA protein production and handling?

Production and handling of recombinant IL11RA protein for rat studies involves several critical considerations:

• Expression Systems:

  • Sf9 Baculovirus cells have been successfully used for rat IL11RA expression, yielding a glycosylated polypeptide of 39.2 kDa (appearing at 40-57 kDa on SDS-PAGE)

  • IL11RA is typically fused with an 8 amino acid His tag at C-Terminus for purification

  • Proper post-translational modifications, especially glycosylation, are important for functional studies

• Purification Techniques:

  • Affinity chromatography using the His tag is standard for initial purification

  • Additional purification via "proprietary chromatographic techniques" has been reported

  • Final product should be sterile filtered to produce a colorless solution

• Buffer Formulation:

  • Optimal formulation: IL11RA protein solution (0.25mg/ml) in Phosphate Buffered Saline (pH 7.4) with 10% glycerol

  • For long-term storage, consider adding a carrier protein (0.1% HSA or BSA)

• Storage Conditions:

  • Short-term (2-4 weeks): Store at 4°C

  • Longer periods: Store frozen at -20°C

  • Avoid multiple freeze-thaw cycles, which can degrade protein structure and function

• Functional Validation:

  • Binding assays: Confirm ability to bind rat IL-11

  • Complex formation: Verify ability to form heterodimeric complexes with gp130

  • Signaling assays: Test ability to initiate or block STAT3 phosphorylation

• Specificity Testing:

  • Test species-specificity of interactions with rat, mouse, and human IL-11

  • Remember that cross-species interactions can lead to partial agonist/antagonist effects

Careful attention to these considerations ensures that recombinant IL11RA protein maintains structural integrity and functional activity for reliable experimental results in rat studies.