K 187in vivo gene expression profile analysis of early diabetic retinopathy
A. M. Joussen1,2, S. Huang1, K. Camphausen1, B. Kirchhof2, A. P. Adamis1
Introduction: Recently, several factors have been identified being operative in initiating vascular complications in diabetes such as leakage, capillary occlusion and finally vascular proliferation. Among these factors are growth factors such as VEGF, bFGF and IGF, but also various adhesion molecules as well as apoptosis related genes. However, a broader examination of gene regulation had not yet been achieved. We analyzed the gene expression profile in early diabetes using cDNA microarrays.
Methods: Long Evans rats were made diabetic with streptozotocin. The temporal program of gene expression for about 5000 genes during diabetic retinopathy was explored with high-density, nylon filter- based cDNA array (Gene FiltersTM). These in vivo gene expression-profiles were verified by RNAse protection assay.
Results: The rat genefilter contained a total of 5147 genes of which 3456 were ESTs and 1691 known genes. At day 3 after induction of diabetes, 27 known genes increased to more than 2 fold. The corresponding numbers for day 7 and day 21 were 60 and 12 respectively. Genes were sorted into different clusters upon their expression profiles. Initial upregulation was frequently only transient and was followed by subsequent decrease of expression. Many features of the transcriptional program appeared to be related to the physiology of inflammation.
Conclusion: Targeting of specific molecular pathways in the treatment of diabetic retinopathy requires a detailed molecular genetic analysis. Gene analysis by by cDNA microarray provides expression profiles which may increase our understanding of complex diseases such as diabetic retinopathy. Beyond providing insight in the general nature of the disease, gene expression profiling will allow efficient identification of potential drug targets.
1Children's Hospital, Harvard Medical School, Boston MA, USA