Abstract
Purpose :
Non-infectious uveitis, a chronic ocular inflammatory disease, is thought to be mostly driven by the adaptive immune system with limited contribution by innate immune pathways such as the inflammasomes. However, the nucleotide-binding oligomerisation domain and leucine-rich repeat receptor-3 (NLRP3) inflammasome pathway has previously been identified as a driver of chronic inflammation in other inflammatory eye diseases such as diabetic retinopathy and age-related macular degeneration. Therefore, in this study we aim to determine whether the NLRP3 inflammasome pathway also plays a role in the pathogenesis of chronic inflammation in the experimental autoimmune uveitis (EAU) mouse model.
Methods :
EAU was induced in 6 to 8-week-old C57BL6J mice via intraperitoneal pertussis toxin and subcutaneous interphotoreceptor retinoid-binding protein (IRBP) injections. After 12 weeks, eyes of EAU (n=6) and control (n=4) mice were enucleated and sections were assessed for inflammasome, macrophage, and microglial markers in addition to a marker for upstream inflammasome activation (Connexin 43) in the retina, ciliary body, and cornea using immunohistochemistry (IHC). Quantification of IHC confocal images and statistical analysis (using students unpaired t-test or two-way ANOVA with Sidak’s multiple comparisons post-hoc test) were carried out by masked researchers.
Results :
Results showed that the expression of NLRP3 (p<0.0001) and cleaved caspase 1 (p<0.0001), markers for inflammasome activation, was significantly upregulated in EAU mouse retinas compared to controls. This correlated with increased astrogliosis and microglial activation throughout the eye. Migratory innate (macrophages and leukocytes) and adaptive (Th17) peripheral immune cells were also found within the retina and ciliary body of EAU mice. Finally, expression of Connexin43 was significantly (p<0.0001) upregulated in the retina and cornea of EAU mice.
Conclusions :
Taken together, our findings suggest that inflammasome activation contributes to the pathogenesis of non-infectious uveitis. Therefore, targeting the inflammasome pathway could be efficacious for non-infectious uveitis treatment.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.