Megan presented her poster, "The Role of Monocytes in Mouse Models of Retinal Degeneration", at the 6th annual Fall Undergraduate Research Festival this past November.
Humans with specific retinal degenerative diseases, including Bardet Biedl syndrome (BBS) and retinitis pigmentosa, have a visible cellular infiltrate in the vitreous of the eye. Rare patient vitreous samples reveal that some cells are monocytes. Due to high morbidity when obtaining human samples, we bred a mouse model of Bbs1M390R/M390R crossed with a cx3cr1-GFP mouse expressing GFP in monocytes and microglia. We obtained mice either heterozygous (unaffected) or homozygous (affected) for retinal degeneration and heterozygous for GFP expression. We performed micron retinal photography, optical coherence tomography, and elecroretinograms (ERG) in vivo before performing whole mount retinal histology. These images and mounts demonstrated monocytes expressing GFP in both Bbs1M390R/M390R cx3cr1GFP/+ and Bbs1M390R/+ cx3cr1GFP/+. After developing standards for quantifying intensity of GFP in vivo and numbers of monocytes in vitro, intensity for affected mice was 63 units compared to 46 for unaffected (p=5E-6). This suggests that mice with retinal degeneration due to Bbs1M390R/M390R have more monocytes than unaffected mice. By utilizing crosses with cx3cr1-GFP mice, we can study monocytes in mouse models of human retinal degeneration diseases. In future studies, we will treat with anakinra (Kineret) to determine whether immune suppression changes the appearance of monocytes, or the course of the disease.