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Published on: June 6, 2025
363
A New Mouse Model of Psoriatic Arthritis
Bahram Razani1, Vinod Chandran2, Kurt de Vlam3
1B. Razani, MD, PhD, Department of Dermatology, University of California, and San Francisco VA Medical Center, San Francisco, California, USA; Bahram.razani@ucsf.edu Barbara.Malynn@ucsf.edu Averil.Ma@ucsf.edu.
The Journal of Rheumatology
|August 15, 2025
Summary
Genetic mutations affecting the A20 protein disrupt immune regulation, leading to psoriatic disease and arthritis. A new mouse model reveals how impaired ubiquitin binding drives sustained inflammation in psoriatic disease.
Area of Science:
- Immunology
- Genetics
- Rheumatology
Background:
- Polymorphisms in the TNFAIP3 locus, encoding A20 protein, are linked to psoriatic disease (PsD).
- A20 functions as a critical negative regulator of inflammation in PsD.
- Reduced A20 expression, due to genetic and epigenetic factors, contributes to PsD pathogenesis.
Purpose of the Study:
- To investigate the role of impaired A20 ubiquitin binding in PsD pathogenesis.
- To characterize a novel mouse model with a mutation in A20's seventh zinc finger.
- To explore the impact of dysregulated innate immune signaling kinetics on PsD.
Main Methods:
- Development of a germline knockin mouse model with a mutation in A20's seventh zinc finger, impairing linear (M1) ubiquitin binding.
- Assessment of spontaneous psoriatic arthritis-like phenotype in these mice.
- Analysis of nuclear factor-κB (NF-κB) signaling dynamics following tumor necrosis factor (TNF) stimulation.
- Evaluation of inflammatory gene transcription patterns.
Main Results:
- The knockin mice spontaneously developed a phenotype resembling psoriatic arthritis.
- These mice exhibited sustained NF-κB signaling after transient TNF stimulation.
- Inappropriate transcription of mid- and late-response inflammatory genes was observed.
- The study highlights dysregulated innate immune-signaling kinetics as a driver of PsD.
Conclusions:
- Impaired A20 binding to linear ubiquitin is implicated in the pathogenesis of psoriatic disease.
- Sustained NF-κB signaling and prolonged inflammatory gene activation contribute to PsD.
- This novel mouse model provides valuable insights into PsD mechanisms and was presented at GRAPPA 2024.
