Microarray for Genes Associated with Signal Transduction in Diabetic OLETF Keratocytes

Purpose: The purpose of this study was to identify differences in signal transduction gene expression between normal and diabetic keratocytes stimulated with interleukin-1α (IL-1α) and tumor necrosis factor-α(TNF-α). Methods: Normal and diabetic keratocytes were primarily cultured and treated with 20 ng/ml IL-1α and TNF-α for 6 h. cDNA was hybridized to an oligonucleotide microarray. Genes identified by the microarray were further evaluated by real-time PCR. Results: Diabetic keratocytes over-expressed components of the MAPK and Notch pathways, and under-expressed components of the insulin, calcium, and TGF-β pathways. Cytokine treated diabetic keratocytes differentially expressed components of the TGF-β and MAPK pathways. After IL-1α and TNF-α treatment, nine genes were under-expressed, falling in the insulin, TGF-β, and Toll-like receptor pathways. Real-time PCR showed a significant decrease in the IL-6 and TGF-β2 genes and a significant increase in the Ppm1a gene. Conclusions: 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-β pathways. In addition, IL-1α and TNF-α stimulating the insulin, TGF-β, and Toll-like receptor signaling pathways may have different effects in diabetic keratocytes.