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Experimental Autoimmune Uveitis: An Intraocular Inflammatory Mouse Model
Published on: January 12, 2022
The alternative complement pathway seems to be a UVA sensor that leads to systemic immunosuppression.
Michael P F Stapelberg1, Rohan B H Williams, Scott N Byrne
1Discipline of Dermatology, Bosch Institute, Sydney Cancer Centre, at the University of Sydney, New South Wales, Australia.
The Journal of Investigative Dermatology
|June 12, 2009
Summary
Ultraviolet A (UVA) light can suppress the immune system, a response linked to the alternative complement pathway. This pathway activation by UVA is genetically restricted and dose-dependent, impacting skin damage responses.
Area of Science:
- Immunology
- Photobiology
- Dermatology
Background:
- Sunlight's ultraviolet (UV) wavebands, including UVA and UVB, possess immunomodulatory properties.
- UVA exposure can induce systemic immunosuppression in a dose-dependent and genetically restricted manner, as observed in mouse models.
- Previous research indicated that higher UVA doses can confer protection against UVB-induced immunosuppression.
Purpose of the Study:
- To elucidate the molecular mechanisms underlying UVA-induced systemic immunosuppression.
- To identify the specific genetic and molecular pathways involved in UVA's differential effects on the immune system.
- To investigate the role of the alternative complement pathway in UVA-induced immune responses.
Main Methods:
- Gene set enrichment analysis of microarray data was employed to identify molecular pathways affected by UVA.
- Real-time reverse transcriptase (RT)-PCR was used for confirmation of gene expression changes.
- Comparative analysis was performed between UVA-responsive (C57BL/6) and non-responsive (BALB/c) mouse strains.
Main Results:
- UVA exposure led to the upregulation of messenger RNA (mRNA) associated with the alternative complement pathway.
- Key complement components (C3, properdin, factor B) were activated by immunosuppressive UVA doses exclusively in UVA-responsive mice.
- High-dose UVA prevented UVB-induced downregulation of chemokine receptor 7 and IL-12B, while decreasing IL-10 levels.
Conclusions:
- Activation of the alternative complement pathway is identified as a primary trigger for UVA-induced systemic immunosuppression.
- The alternative complement pathway acts as a crucial sensor for UVA-induced skin damage.
- Genetic background and UVA dose critically influence the systemic immune response to UV radiation.
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