Lupus is a spectrum disease, with some patients experiencing primarily skin involvement and others facing life-threatening systemic complications affecting kidneys, joints, and more. A major challenge to study the pathogenesis of lupus has been the lack of an animal model that accurately mirrors the progression and the dynamic shift between disease states. On February 3, 2026, a research team led by Prof. Qianjin Lu from the Chinese Academy of Medical Sciences & Peking Union Medical College Institute of Dermatology published a research article in Volume 2 of the journal Immunity & Inflammation that addressed this limitation.
The research team first analyzed human data, confirming that PPARγ—a key regulatory protein—was significantly reduced in the skin keratinocytes of both cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE) patients, but not in healthy individuals or those with other inflammatory skin conditions. This indicated a specific molecular change in the skin associated with lupus.
Mimicking this human condition, the team engineered a novel mouse model using inducible, keratinocyte-specific gene editing to knock out the Pparg gene precisely in skin cells. By varying the extent and duration of PPARγ loss in the skin, researchers could control the disease state: when Pparg deletion was limited to a small skin area, mice developed CLE-like symptoms—skin inflammation and lesions—without significant systemic autoimmunity. Crucially, when the deletion was expanded across larger skin areas, the mice progressively developed the hallmarks of SLE: high levels of autoimmune antibodies, immune complex deposits in the kidneys (indicative of lupus nephritis), proteinuria, and multi-organ inflammation. This demonstrated a direct, dose-dependent link between the skin defect and systemic disease.
Unlike traditional models, this system exhibits dynamic features of human lupus. Following a single induction, both skin and systemic symptoms could spontaneously alleviate over time, modeling a clinical remission phase. Remarkably, re-inducing the genetic change could re-trigger and stabilize the SLE-like phenotype, modeling disease recurrence. This reversibility and controllability allow scientists to study not just disease onset, but also remission and relapse cycles.
The model also successfully recapitulated a critical clinical feature: photosensitivity. Exposure to ultraviolet (UV) light, a known trigger in human patients, significantly worsened the skin lesions and accelerated the transition from localized CLE to systemic SLE in the mice. This validates the model's relevance for studying environmental triggers.
" This model bridges a critical gap, " the authors note. " It provides the first experimental evidence in an immunocompetent organism that a primary defect in the skin can be the force driving a progressive, systemic autoimmune response. We can now trace, in real-time, how the disease may progress from the skin to the body. "
Insights and Applications
Built on a common C57BL/6 genetic background without complex inducing mutations, the model offers a system to study core disease mechanisms. Its high penetrance, short modeling time, and responsiveness to environmental triggers like UV light make it highly practical.
Beyond mechanism, the model has proven effective for therapeutic testing. Both systemic immunosuppressive treatments and topical interventions targeting the skin showed clear and measurable efficacy, highlighting its potential as a platform for screening new drugs and evaluating treatment strategies for different stages of the lupus spectrum.
" This is more than a model; it's a new experimental paradigm, " said Professor Lu. " It positions the skin not just as a target in lupus, but as a potential initiator and controller of systemic disease. This opens new avenues for understanding disease progression and developing stage-specific interventions. "
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About Immunity & Inflammation
Immunity & Inflammation is a newly launched open-access journal co-published by the Chinese Society for Immunology and Springer Nature under the leadership of Editors-in-Chief Prof. Xuetao Cao and Prof. Jules A. Hoffmann. Immunity & Inflammation aims to publish major scientific questions and cutting-edge advances that explore groundbreaking discoveries and insights across the spectrum of immunity and inflammation, from basic science to translational and clinical research.
Website: https://link.springer.com/journal/44466
About Authors
Prof. Qianjin Lu from Chinese Academy of Medical Sciences & Peking Union Medical College
Prof. Lu is a Tenured Professor at Peking Union Medical College, Executive Director of the Institute of Dermatology at the Chinese Academy of Medical Sciences, and served as the 15th Chairman of the Dermatology and Venereology Branch of the Chinese Medical Association. As the primary investigator, he has received numerous awards including the National Science and Technology Progress Award (Second Class), the ILDS Distinguished Service Award, the NACDA Distinguished Research Achievement Award in Dermatology, the Ho Leung Ho Lee Foundation Award for Outstanding Chinese Physicians, the Wu Jieping-Paul Janssen Medical Award, the Tan Jiazhen Clinical Medicine Award, and the National Award for Innovation and Excellence. His research focuses on the pathogenesis and clinical diagnosis and treatment of immune-related skin diseases.
Dr. Jingru Tian from Chinese Academy of Medical Sciences
Dr. Tian is an attending physician in the Department of Allergy & Rheumatology-Immunology at the Chinese Academy of Medical Sciences Institute of Dermatology. Her research focuses on autoimmune skin diseases.
Dr. Liqing Shi from Chinese Academy of Medical Sciences
Dr. Shi is a physician at the Chinese Academy of Medical Sciences Institute of Dermatology. Her research focuses on autoimmune skin diseases.
Funding information
This work was supported by the National Key R&D Program of China (2022YFC3601800), the National Natural Science Foundation of China (82595960, 82430102, 32141004, 82203933), CAMS Innovation Fund for Medical Sciences (2021-I2M-1-059, 2025-I2M-XHXX-162), the Non-profit Central Research Institute Fund of CAMS (2020-RC320-003), the Science and Technology Innovation Program of Hunan Province (2022RC4026).
Experimental study
Animals
Proinflammatory Keratinocytes Drive a Novel Mouse Model of Autoimmunity with Systemic and Cutaneous Lupus Erythematosus
3-Feb-2026
The authors declare no competing interests.