Microarray for genes associated with signal transduction in diabetic OLETF keratocytes

The purpose of this study was to identify differences in signal transduction gene expression between normal and diabetic keratocytes stimulated with interleukin-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha). Normal and diabetic keratocytes were primarily cultured and treated with 20 ng/ml IL-1alpha and TNF-alpha for 6 h. cDNA was hybridized to an oligonucleotide microarray. Genes identified by the microarray were further evaluated by real-time PCR. Diabetic keratocytes over-expressed components of the MAPK and Notch pathways, and under-expressed components of the insulin, calcium, and TGF-beta pathways. Cytokine treated diabetic keratocytes differentially expressed components of the TGF-beta and MAPK pathways. After IL-1alpha and TNF-alpha treatment, nine genes were under-expressed, falling in the insulin, TGF-beta, and Toll-like receptor pathways. Real-time PCR showed a significant decrease in the IL-6 and TGF-beta2 genes and a significant increase in the Ppm1a gene. There were some differences in gene expression between normal and diabetic keratocytes related to signal transduction pathways, such as the insulin, MAPK, calcium, and TGF-beta pathways. In addition, IL-1alpha and TNF-alpha stimulating the insulin, TGF-beta, and Toll-like receptor signaling pathways may have different effects in diabetic keratocytes.