IL36RN Human

What is the genomic organization of IL36RN and how does it relate to other IL-1 family members?

IL36RN is one of nine IL-1 family genes (IL1A, IL1B, IL37, IL36A, IL36B, IL36G, IL36RN, IL38, IL1RN) located on human chromosome 2q13 clustered within 430 kb . This clustering suggests they originated from a common ancestral gene that underwent multiple gene duplications. The IL36RN gene specifically encodes IL-36Ra, which functions as a signaling inhibitor in the IL-36 pathway.

From an evolutionary perspective, the close proximity of these genes in the IL-1 cluster indicates a shared ancestry and functional relationship. The IL-1 cluster genes show conservation of protein structure, specifically a 12-strand beta-trefoil (12SBT) structure, with similar immunomodulatory functions . Understanding this genomic organization provides important context for interpreting mutations and their functional impacts.

Methodologically, researchers investigating the genomic organization should employ:

• Comparative genomic analysis across species

• Phylogenetic studies of IL-1 family genes

• Functional analysis of conserved regions

How does IL-36Ra mechanistically inhibit IL-36 signaling?

IL-36Ra (encoded by IL36RN) functions as a competitive antagonist by binding to IL-36R without allowing productive engagement with IL-1RAcP (IL-1 receptor accessory protein) . This mechanism differs fundamentally from receptor blockade:

• IL-36Ra binds to IL-36R with high affinity

• This binding prevents IL-36 agonists (IL-36α, IL-36β, IL-36γ) from engaging the receptor

• Most critically, IL-36Ra binding prohibits recruitment of IL-1RAcP, which is essential for signal transduction

• Without IL-1RAcP recruitment, downstream signaling molecules (MyD88, IRAKs, TRAF6) cannot assemble properly

• This prevents activation of NF-κB and MAPK pathways that would normally trigger inflammatory responses

To experimentally verify this mechanism, researchers should employ:

• Binding affinity studies comparing IL-36Ra vs. IL-36 agonists

• Co-immunoprecipitation experiments examining receptor complex formation

• Reporter assays measuring NF-κB or MAPK activation

• Structural studies of IL-36Ra/IL-36R interactions

What are the most prevalent IL36RN mutations across different ethnic populations?

Research indicates significant ethnic variation in IL36RN mutation patterns:

The c.115+6T>C mutation appears particularly prevalent in Chinese populations, occurring in multiple independent studies . When designing genetic screening protocols, researchers should:

• Employ population-appropriate mutation panels

• Consider whole exome sequencing for novel mutation discovery

• Validate findings with functional assays

• Use matched control populations for accurate interpretation of results

How should researchers approach IL36RN genotype-phenotype correlation studies?

Effective genotype-phenotype correlation studies require:

• Precise clinical categorization:

  • GPP alone vs. GPP with psoriasis vulgaris (GPP+PV)

  • Adult vs. pediatric onset (IL36RN mutations strongly correlate with early onset)

  • Disease severity metrics (PASI scores, hospitalization frequency)

• Comprehensive genetic analysis:

  • Full sequencing of IL36RN coding and splice regions

  • Analysis of copy number variations

  • Consideration of modifier genes

• Statistical approaches:

  • Multivariate analysis controlling for confounding factors

  • Stratification by mutation type (nonsense, missense, splice-site)

  • Meta-analytic methods for combining data across cohorts

The evidence indicates IL36RN mutations occur approximately 3.82 times more frequently in GPP alone compared to GPP+PV (95% CI, 2.63–5.56), with similar effect sizes in European (OR = 4.03, 95% CI, 2.23–7.26) and Asian populations (OR = 3.69, 95% CI, 2.27–6.00) .

What cell models are most appropriate for studying IL36RN function?

Several cell models offer distinctive advantages for IL36RN research:

• Keratinocytes:

  • Primary human keratinocytes most accurately reflect physiological conditions

  • Immortalized lines (HaCaT, A-431) provide experimental consistency

  • Express IL-36 cytokines naturally and respond to inflammatory stimuli

  • Allow study of endogenous IL-36 protein processing

• Intestinal epithelial cells:

  • HT-29 cells express endogenous IL-36R

  • Can be stably transfected with reporter constructs (e.g., NF-κB)

  • Suitable for pharmacological screening

• Other validated models:

  • Human ovarian tumor line NCI/ADR-RES (first reported for endogenous IL-36R signaling)

  • Mouse macrophage line RAW264.7

  • Primary bronchial epithelial cells

  • Articular chondrocytes and synovial fibroblasts

When selecting models, researchers should consider:

• Expression levels of IL-36 pathway components

• Tissue relevance to disease of interest

• Availability of genetic modification tools

• Reproducibility of inflammatory responses

What techniques can quantitatively assess IL-36Ra functionality?

Multiple complementary approaches provide robust assessment of IL-36Ra function:

• Protein activity assays:

  • NF-κB reporter gene systems (HT-29 cells with stable NF-κB reporter)

  • EC50 determination comparing wild-type and mutant IL-36Ra

  • Dose-response curves with varying IL-36Ra:IL-36 ratios

• Biochemical approaches:

  • Surface plasmon resonance for binding kinetics

  • Proteolytic processing analysis (important for activation)

  • Co-immunoprecipitation to assess receptor complex formation

• Cellular response measurements:

  • Quantification of IL-36-induced cytokines (RT-qPCR, ELISA)

  • Phosphorylation of downstream signaling components (Western blot)

  • Neutrophil recruitment assays (transwell migration)

• Advanced methodologies:

  • Live-cell imaging of signaling dynamics

  • CRISPR-Cas9 gene editing to confirm receptor specificity

  • Single-cell analysis of response heterogeneity

Timing is critical - the NF-κB response to IL-36 stimulation peaks between 3-9 hours, making this window optimal for experimental measurements .

How do IL36RN mutations impact proteolytic processing of IL-36 family cytokines?

Proteolytic processing represents a critical regulatory step for IL-36 cytokines:

• N-terminal truncation mechanism:

  • Full-length IL-36 proteins have limited activity

  • Specific N-terminal truncation dramatically increases activity (e.g., n5-IL-36γ, n6-IL-36β)

  • IL-36Ra may require similar processing for optimal function

• Protease involvement:

  • Neutrophil-derived serine proteases can cleave IL-36 proteins

  • Chymotrypsin digestion of IL-36 produces multiple cleavage products

  • Apoptotic stimuli (cycloheximide, staurosporine) induce processing of endogenous IL-36γ

• Research approaches:

  • In vitro digestion with purified proteases

  • Mass spectrometry identification of cleavage sites

  • Activity comparison of different N-terminal variants

  • Co-culture systems with neutrophils and IL-36-producing cells

Research indicates that IL36RN mutations may disrupt not only IL-36Ra production but potentially alter its processing, affecting the balance between active and inactive forms of both the antagonist and agonists.

What synergistic pathways interact with IL-36 signaling in inflammatory conditions?

Understanding pathway interactions is crucial for comprehensive IL36RN research:

• Cross-regulation with other IL-1 family members:

  • Shared use of IL-1RAcP co-receptor creates competitive interactions

  • IL-38 and IL-1Ra may provide compensatory antagonism when IL-36Ra is deficient

• Documented synergistic stimuli:

  • TNF synergizes with PMA or flagellin to induce IL-36γ expression

  • IL-1β and TNF increase IL-36α and IL-36γ mRNAs in epithelial cells

  • Staphylococcus aureus combined with TNF induces endogenous IL-36γ protein

• Inflammasome connections:

  • UV radiation activates inflammasomes in human keratinocytes

  • Potential cross-talk between IL-1β and IL-36 signaling

• Experimental approaches:

  • Combinatorial stimulation experiments

  • Conditional knockout models

  • Multiplex cytokine profiling

  • Phospho-proteomic analysis of signaling networks

These interactions suggest IL36RN mutations may have broader impacts beyond direct IL-36 pathway dysregulation, potentially explaining phenotypic heterogeneity in patients.

How can single-cell technologies advance IL36RN research?

Single-cell approaches offer transformative opportunities for IL36RN research:

• Cellular heterogeneity insights:

  • Identification of specific cellular subsets that express/respond to IL-36

  • Characterization of variable penetrance of IL36RN mutations at cellular level

  • Discovery of compensatory mechanisms in individual cells

• Disease-relevant applications:

  • Profiling of skin lesions from GPP patients with/without IL36RN mutations

  • Comparison of transitional states between healthy and inflamed tissue

  • Monitoring of treatment responses at single-cell resolution

• Methodological approaches:

  • scRNA-seq to identify transcriptional signatures

  • CyTOF for protein-level phenotyping

  • Spatial transcriptomics to preserve tissue context

  • Single-cell ATAC-seq for epigenetic regulation

• Analytical considerations:

  • Trajectory analysis to map inflammatory progression

  • Integration with genetic data

  • Cell-cell interaction modeling

  • Pseudo-time analysis of IL-36 pathway activation

These technologies could resolve longstanding questions about cell-specific roles in IL36RN-related pathology that bulk approaches cannot address.

How does IL36RN mutation status impact GPP clinical presentation and treatment response?

The relationship between IL36RN genotype and clinical phenotype shows distinctive patterns:

• Clinical subtype associations:

  • IL36RN mutations more strongly associated with GPP alone than GPP+PV (OR 3.82, 95%CI 2.63-5.56)

  • Consistent association observed across both European and Asian populations

  • Strong correlation with early-onset disease

• Treatment implications:

  • IL36RN mutation carriers may respond differently to conventional treatments

  • Targeted IL-36 pathway inhibitors potentially more effective in mutation carriers

  • Genotyping could inform personalized therapeutic approaches

• Research design considerations:

  • Retrospective analysis of treatment outcomes stratified by mutation status

  • Prospective clinical trials incorporating IL36RN genotyping

  • Development of mutation-specific biomarkers for treatment monitoring

A comprehensive approach should include:

• Standardized clinical assessment protocols

• Long-term follow-up to capture recurrence patterns

• Pharmacogenetic analyses

• Correlation with other genetic factors (HLA status, CARD14 mutations)

What models best recapitulate IL36RN-deficient GPP for therapeutic development?

Developing representative disease models requires multiple complementary approaches:

• Cellular models:

  • Primary keratinocytes from IL36RN-mutant patients

  • CRISPR-engineered cell lines with specific patient mutations

  • 3D skin equivalents incorporating IL36RN-deficient keratinocytes

  • Co-culture systems with immune cells to model inflammatory cascade

• Animal models:

  • Conventional IL36RN knockout mice

  • Humanized mouse models expressing patient-specific mutations

  • Conditional tissue-specific IL36RN deletion

  • Xenograft models using patient-derived cells

• Ex vivo approaches:

  • Skin explant cultures from patient biopsies

  • Precision-cut tissue slices with ex vivo drug testing

  • Microfluidic organ-on-chip technologies

• Validation criteria:

  • Recapitulation of histological features of pustular psoriasis

  • Similar transcriptional profiles to patient lesions

  • Appropriate inflammatory cell recruitment

  • Response to established therapies mirroring clinical observations

These models provide platforms for both mechanistic studies and preclinical therapeutic testing.

How are IL36RN mutations distributed across different GPP patient populations?

Meta-analysis data reveals important distribution patterns:

Key findings include:

• Nearly equal distribution between GPP alone (332) and GPP+PV (351) in the total cohort

• Significantly higher frequency of IL36RN mutations in GPP alone vs. GPP+PV

• Higher mutation rates observed in pediatric cases

• Consistent pattern across different ethnic populations

This data supports distinct genetic mechanisms in GPP subtypes and highlights the importance of standardized patient classification in research studies.

What is the specific mutation spectrum of IL36RN across populations?

Molecular characterization of IL36RN mutations shows population-specific patterns:

Notable observations:

• c.115+6T>C appears consistently across Chinese studies

• Some mutations (c.28C>T) show population-specific prevalence

• Multiple studies used RFLP-PCR and Sanger sequencing, providing methodological consistency

• A polymorphism of c.115+6T>C specifically led to IL36RN mutation in 393 cases

This mutation spectrum informs targeted genotyping approaches and highlights potential founder effects in different populations.

What experimental approaches can uncover the regulation of endogenous IL-36 activity?

Investigating endogenous IL-36 regulation requires multi-faceted approaches:

• Transcriptional regulation:

  • Characterization of promoter elements controlling IL36RN expression

  • Identification of transcription factors regulating IL36RN

  • Analysis of epigenetic modifications affecting IL36RN expression

• Post-translational processing:

  • Identification of specific proteases activating IL-36 cytokines in vivo

  • Characterization of inhibitors of proteolytic processing

  • Investigation of how cellular stress affects processing

• Pathway integration:

  • Mapping interactions between IL-36 and other inflammatory pathways

  • Investigation of synergistic stimuli (e.g., TNF with PMA or flagellin)

  • Characterization of tissue-specific regulatory mechanisms

• Novel methodologies:

  • CRISPR screens to identify regulatory genes

  • Proximity labeling to identify protein-protein interactions

  • Advanced imaging to track IL-36 processing and trafficking

Data shows that stimuli like IL-1β, TNF, PMA, and flagellin induce IL-36α and IL-36γ expression in epithelial cells, with IL-36γ being the most abundant . Understanding these regulatory mechanisms may reveal new therapeutic targets.

How might understanding IL36RN mutations impact precision medicine approaches for inflammatory skin diseases?

IL36RN research has significant implications for precision dermatology:

• Diagnostic applications:

  • Development of targeted genotyping panels for GPP patients

  • Creation of risk prediction algorithms incorporating IL36RN status

  • Identification of biomarkers correlating with IL36RN function

• Therapeutic stratification:

  • Selection of biologics based on IL36RN mutation status

  • Dose optimization guided by genetic profile

  • Timing of therapeutic intervention (earlier for high-risk genotypes)

• Novel therapeutic approaches:

  • Development of recombinant IL-36Ra variants resistant to degradation

  • Small molecule stabilizers of mutant IL-36Ra

  • Gene therapy to correct IL36RN mutations

  • IL-36R-targeted monoclonal antibodies

• Research infrastructure needs:

  • Integration of genotypic and phenotypic data in clinical registries

  • Biobanking initiatives for IL36RN-mutated patient samples

  • Collaborative networks for studying rare genotype combinations

The strong genetic association between IL36RN mutations and specific GPP subtypes provides a foundation for more targeted therapies in this difficult-to-treat condition.