GENE EXPRESSION CHANGES WITHIN MÜLLER GLIAL CELLS DURING RETINITIS PIGMENTOSA

Retinitis Pigmentosa (RP) is a progressive retinal degeneration in which the retina loses nearly all of its photoreceptor cells and undergoes major structural changes. Little is known regarding the role the resident glia, the Müller glia, play in the progression of the disease. Here we define gene expression changes in Müller glial cells (MGCs) from two different mouse models of RP, the retinal degeneration 1 (rd1) and rhodopsin knock-out (Rhod-ko) models. The RNA repertoire of 28 single MGCs was comprehensively profiled, and a comparison was made between MGC from wild type (WT) and mutant retinas. Two time points were chosen for analysis, one at the peak of rod photoreceptor death and one during the period of cone photoreceptor death. MGCs have been shown to respond to retinal degeneration by undergoing gliosis, a process marked by the upregulation of GFAP. In this data, many additional transcripts were found to change. These can be placed into functional clusters, such as retinal remodeling, stress response, and immune related response. It is noteworthy that a high degree of heterogeneity among the individual cells was observed, possibly due to their different spatial proximities to dying cells, and/or inherent heterogeneity among MGCs. Retinas were dissociated and single Muller Glial Cells were picked under a dissecting microscope using a micropipette based on their distinct morphological shape. Single cell cDNAs were generated and genome wide profiles were obtained by hybridization to Affymetrix 430 2.0 microarrays. Data was normalized using MAS5.0 software. A total of 28 Muller Glial Cells were analyzed and confirmed post hoc by expression of known marker genes.