Abstract
Purpose: :
It has been suggested that müller cell dysfunction may contribute to neuronal damage in some retinal diseases such as diabetic retinopathy and macular telangeictasia type 2. The purpose of the study is to identify genes that are differentially expressed (DE) between retinae of transgenic mice, in which patchy müller cell ablation has been conditionally induced, and the wild type mice.
Methods: :
Transgenic mice, in which a müller cell specific promoter (Rlbp1) has been linked to a gene encoding DTA176 toxin with a Cre-ER system, and wild type mice received 4 consecutive tamoxifen injections to activate transcription of the gene encoding the toxin. All mice were sacrificed at 3 different time points (1 week, 1 month and 3 months) after administration of tamoxifen and retinas were collected. After RNA extraction (Qiagen cat#74104), 1st and 2nd strand cDNA were synthesized, purified and biotin labelled for hybridization (Affy mouse gene 1.0 ST arrays). The scanned data were analysed and validated with qRT-PCR.
Results: :
At the 3 different time points, there were 395 (309 upregulated [U] and 86 downregulated [D]), 126 (58U, 68D), 123 (46U, 77D) DE genes respectively. Most of genes were differentially expressed at 1 week. These either remianed up-regulated or subsided in the later stages. Up-regulated DE genes were related to proteolysis, apoptosis, prostaglandin biosynthetic process and MAPK activity, whereas down-regulated genes were associated with glucose metabolism, regulation of cell adhesion, cytolysis and actin cytoskeleton organization. qRT-PCR result was consistant with microarray data.
Conclusions: :
Many DE genes found in this study were related to putative consequences of müller cell dysfunction such as vascular leak, apoptosis and glucose metabolism. Further research comparing tissue obtained from patches of müller cell ablation using laser capture microdissection with normal retina will shed further light on the contribution of müller cell dysfunction to retinal disease.
Keywords: Muller cells • retinal glia • gene microarray