In the fieldof immunotherapy, IL-4Rα serves as the shared receptor for the two key inflammatory pathways, IL-4 and IL-13, playing a central regulatory role in type 2 immune responses. It is a significant therapeutic target in areas such as asthma and atopic dermatitis. The targeted drug Dupilumab achieved global sales close to $14.1 billion in 2024, demonstrating immense commercial potential. With the remarkable commercial success of drugs like Dupilumab and the continuous expansion of their indications from dermatological and respiratory diseases to the tumor microenvironment, IL-4Rα has emerged as another star target, alongside PD-1, possessing high clinical translation value and broad market prospects.
 

Target Analysis: The Super-Hub of Type 2 Immunity
 

Interleukin-4 Receptor Alpha (IL-4Rα, also known as CD124) is a key memberof the immunoglobulin superfamily and serves as the common signaling subunit for the two critical type 2 cytokines, IL-4 and IL-13. Structurally, IL-4Rα is a transmembrane glycoprotein receptor widely expressed on the surfaceof various immune cells (e.g., B cells, T cells, macrophages) and also on non-hematopoietic cells (e.g., keratinocytes, epithelial cells, fibroblasts). IL-4Rα forms two functionally distinct receptor complexes by combining with different ligand subunits: The Type I receptor, composed of IL-4Rα and the common gamma chain (γc), binds specifically to IL-4 and is primarily expressed on hematopoietic immune cells. The Type II receptor, composed of IL-4Rα and IL-13Rα1, can be activated by either IL-4 or IL-13 and is widely expressed on non-hematopoietic cells.
 

Pathogenic Mechanisms of IL-4Rα in Three Major Diseases
 

Atopic Dermatitis (AD)
 

IL-4Rα, as the key common receptor for IL-4/IL-13 signaling, is the central hub in the pathogenesis of Atopic Dermatitis (AD). In keratinocytes, IL-4/IL-13 activates the JAK1/TYK2-STAT6 pathway via the Type II receptor (IL-4Rα/IL-13Rα1), significantly suppressing the synthesis of key differentiation proteins like Filaggrin and long-chain ceramides, thereby disrupting the skin barrier. Simultaneously, IL-4 acts on lymphoid cells via the Type I receptor, inducing Th2 differentiation and B cell IgE class switching, while also upregulating IL-31Rα to enhance neuronal itch signaling. This pathway also inhibits antimicrobial peptide expression and promotes Staphylococcus aureusadhesion, ultimately leading to barrier defects that initiate immune dysregulation, which in turn promotes microbial colonization, creating a vicious cycle where microbial colonization exacerbates itching and scratching.
 

Asthma
 

IL-4Rα, as the common receptor subunit for IL-4 and IL-13, is the central hub driving the pathogenesis of type 2 asthma (T2-high asthma). Upon ligand binding to Type I or Type II receptors, JAK1/JAK3 or JAK1/TYK2 kinases are activated, which subsequently phosphorylate STAT6. Phosphorylated STAT6 forms dimers that translocate to the nucleus to initiate transcription of key genes. At the airway structural level, STAT6 directly regulates airway epithelial cells, inducing goblet cell metaplasia, excessive mucus secretion (e.g., MUC5AC), and airway hyperresponsiveness. Concurrently, it promotes eosinophil (EOS) infiltration and smooth muscle hyperplasia, ultimately leading to asthma attacks characterized by IgE-mediated allergic reactions, chronic eosinophilic inflammation, airway mucus plugs, and airflow limitation.
 

 

Image source: IL-4/IL-13 axis as therapeutic targets in allergic rhinitis and asthma
 

Cancer
 

IL-4Rα drives the formation and progression of micro-tumors in the tumor microenvironment by mediating Type I and Type II IL-4 receptor signaling. On one hand, IL-4 binding to IL-4Rα induces the heterodimerization of IL-4Rα with the γC subunit to form the Type I IL-4R in hematopoietic cells (e.g., lymphocytes). This activates JAK proteins, subsequently initiating two major pathways—IRS/PI3K/AKT and JAK/STAT6—promoting IL-4-responsive gene transcription and mTOR-dependent T cell differentiation to regulate immune cell function. On the other hand, in epithelial-derived tumor cells and stromal cells within the microenvironment, IL-4Rα combines with the IL13Rα1 subunit to form the Type II IL-4R. IL-4 activates multiple downstream pathways via this receptor—PI3K/AKT, MAPK/ERK, JAK/STAT6, and mTOR—directly enhancing the migration, invasion, survival, and proliferative capabilities of cancer cells, while also inducing glucose and glutamine metabolic reprogramming to support tumor growth.
 

Image source: Targeting IL4/IL4R for the treatment of epithelial cancer metastasis
 

Mouse Models
 

IL-4Rα -/- Mice:​ Complete knockout of the IL-4Rαgene, resulting in the loss of both Type I and Type II IL-4 receptor signaling. This is a classic model for studying the core role of IL-4Rα in systemic immune regulation.
 

IL-4/IL-4Rα Double Humanized Mice:​ Simultaneously express human IL-4 and human IL-4Rα. These mice are used to evaluate the efficacy and safety of humanized antibody drugs and serve as a standard model for researching human-specific IL-4Rα-targeted therapies.
 

IL-4Rα fl/fl K14-Cre Mice:​ Conditional knockout of IL-4Rα specifically in keratinocytes (the primary cell type of the epidermis). This allows precise study of its local functional mechanisms in the skin barrier, inflammatory responses, and the tumor microenvironment.
 

Supporting Research
 

Gene therapy offers hope for common diseases, but its development and validation rely heavily on animal model support. MingCeler Biotech, leveraging its self-developed TurboMice™ technology, has developed multiple disease mouse models. The TurboMice™ technology overcomes the technical challenges of long mouse model generation cycles and low success rates for complex models, enabling editing at almost any target gene locus. Complete homozygous gene-edited mouse models can be prepared directly from embryonic stem cells in as little as two months.
 

MingCeler Biotech​ can customize various IL-4Rα-related mouse models according to client needs, such as IL-4Rα -/- mice, IL-4/IL-4Rα double humanized mice, and IL-4Rα fl/fl K14-Cre mice. Inquiries are welcome.
 

References:

1.Bankaitis KV, Fingleton B. Targeting IL4/IL4R for the treatmentof epithelial cancer metastasis. Clin Exp Metastasis. 2015 Dec;32(8):847-56. doi: 10.1007/s10585-015-9747-9. Epub 2015 Sep 18. PMID: 26385103; PMCID: PMC4651701.

2.Nur Husna SM, Md Shukri N, Mohd Ashari NS, Wong KK. IL-4/IL-13 axis as therapeutic targets in allergic rhinitis and asthma. PeerJ. 2022 May 30;10:e13444. doi: 10.7717/peerj.13444. PMID: 35663523; PMCID: PMC9161813.