Microarray Analysis for Genes Associated with Angiogenesis in Diabetic OLETF Keratocytes

The purpose of this study was to identify the differences in angiogenesis gene expression between normal and diabetic keratocytes stimulated with interleukin-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha). Primarily cultured normal and diabetic keratocytes were treated with 20 ng/mL of IL-1a and TNF-alpha for 6 hr. cDNA was hybridized to an oligonucleotide microarray. Microarray analysis was used to identify differentially expressed genes that were further evaluated by real-time polymerase chain reaction (RT-PCR). Diabetes keratocytes overexpressed vital components of angiogenesis including Agtr1, and under-expressed components related to the blood vessel maturation, including Dcn. Cytokine-treated diabetic keratocytes differentially expressed components of angiogenesis. OLETF keratocytes after treatment with IL-1alpha and TNF-alpha showed the newly expressed 15 and 14 genes, respectively. Newly and commonly under-expressed five genes followed by treatment with both IL-1alpha and TNF-alpha were also evident. RT-PCR showed results similar to the microarray results. Agtr1 and Itga1 showed an increased expression in diabetic keratocytes compared with normal corneal keratocytes, especially after TNF-alpha treatment. Il6 appeared strong expression after interleukin-1alpha treatment, but showed down expression after TNF-alpha treatment. Further studies to analyze and confirm the significance of the identified angiogenetic genes of diabetes are needed.

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-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha). METHODS: 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. RESULTS: 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. 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-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.