Responses of Multipotent Retinal Stem Cells to IL-1ß, IL-18, or IL-17.

Purpose. To investigate how multipotent retinal stem cells (RSCs) isolated from mice respond to the proinflammatory signaling molecules, IL-1ß, IL-18, and IL-17A. Materials and Methods. RSCs were cultured in a specific culture medium and were treated with these cytokines. Cell viability was detected by MTT assay; ultrastructure was evaluated by transmission electron microscopy; expression of IL-17rc and proapoptotic proteins was detected by immunocytochemistry and expression of Il-6 and Il-17a was detected by quantitative RT-PCR. As a comparison, primary mouse retinal pigment epithelium (RPE) cells were also treated with IL-1ß, IL-18, or IL-17A and analyzed for the expression of Il-6 and Il-17rc. Results. Treatment with IL-1ß, IL-18, or IL-17A decreased RSC viability in a dose-dependent fashion and led to damage in cellular ultrastructure including pyroptotic and/or necroptotic cells. IL-1ß and IL-18 could induce proapoptotic protein expression. All treatments induced significantly higher expression of Il-6 and Il-17rc in both cells. However, neither IL-1ß nor IL-18 could induce Il-17a expression in RSCs. Conclusions. IL-1ß, IL-18, and IL-17A induce retinal cell death via pyroptosis/necroptosis and apoptosis. They also provoke proinflammatory responses in RSCs. Though IL-1ß and IL-18 could not induce Il-17a expression in RSCs, they both increase Il-17rc expression, which may mediate the effect of Il-17a.

Implications of DNA leakage in eyes of mutant mice.

Extranuclear DNA (enDNA) is not well studied ultrastructurally in the retinal pigment epithelium (RPE). We analyzed the retina and vastus medialis muscle of four mouse strains that are related to focal retinal degeneration by transmission electron microscopy (TEM) and EM immunolabeling. Evaluation of enDNA would imply the involvements of enDNA is either limited to the affected tissue or generalized in the whole body. Ultrastructural analysis and EM immunolabeling revealed that enDNA was present in the RPE cells but not in the muscle. These data suggest that enDNA could be unique to unhealthy RPE and a potential biomarker for cellular abnormality.