title: The effect of interleukin-1 on cytokine gene expression by human corneal epithelial cells.
abstract: The purpose of this study was to characterize the pattern of cytokine gene expression by human corneal epithelial cells (HCEC) in response to interleukin-1 (IL-1). Primary cultured HCEC (P-HCEC) or SV40 transformed HCEC (SV40-HCEC) were treated for 6 hr with serum-free growth-media alone or with recombinant human IL-1beta or IL-1alpha (10 ng ml(-1)). 33P labeled cDNA was generated from total RNA, then hybridized to a human cytokine expression array. An autoradiograph was generated for each experimental condition and results analysed semi-quantitatively. Reverse transcription polymerase chain reaction (RT-PCR) was performed to detect mRNA for IL-8, growth related oncogene-beta (GRO-beta), intercellular adhesion molecule (ICAM)-1 and Ephrin A5. P-HCEC and SV40-HCEC demonstrated comparable cytokine profiles. For P-HCEC (n=2) the expression of 35 genes was upregulated or only detectable following IL-1beta treatment whereas the expression of nine genes was downregulated or undetectable after IL-1beta treatment. In SV40-HCEC (n=3), the expression of 48 genes was upregulated or only detectable following IL-1beta treatment and the expression of 10 genes was downregulated or undetectable after IL-1beta treatment. Some genes that demonstrated increased expression included cadherin-5, ICAM-1, GRO-alpha, GRO-beta, GRO-gamma, Activin A (bA subunit), tumor necrosis factor-alpha, IL-6, and IL-8. Genes that showed decreased expression included the chemokine receptor-CXCR-4, ciliary neurotrophic factor (CNTF), c-kit ligand, Ephrin A5, G-protein coupled receptor RDC-1 and FGF family FGFR2. Bayesian analysis of the SV40-HCEC data (n=3) revealed the expression of 15 genes that were significantly (p<0.05) differentially regulated. Within these 15 genes, the expression of chemokines (GRO-alpha, GRO-beta, IL-8), fibroblast growth factor 13 and the cytokine IL-6 were the most upregulated, while ephrin A5 and chemokine receptor-4 were the most downregulated. IL-1alpha treatment (n=1 P-HCEC; n=1 SV40-HCEC) produced results very similar to IL-1beta treatment. RT-PCR revealed differential regulation of IL-8, GRO-beta, ICAM-1 and ephrin A5 in accordance with gene array data. In conclusion, the data demonstrate that IL-1 treatment of HCEC differentially regulates the expression of other cytokine and related genes, thus adding to the body of evidence that IL-1 is a major mediator of ocular surface inflammatory reactions. Since the expression of a large number of genes can be studied simultaneously, gene array studies such as these offers the advantage of understanding global changes in response to a specific stimulus. Thus our study provides insight in to the ocular surface response in conditions of inflammation and corneal wound healing where the levels of IL-1 are known to be increased.
authors.affiliation: College of Optometry, University of Houston, 505 J. Davis Armistead Building, 4901 Calhoun Road, Houston, TX 77204-2020, USA.
authors.forename: Srihari
authors.initials: S
authors.lastname: Narayanan
authors.forename: Adrian
authors.initials: A
authors.lastname: Glasser
authors.forename: Ying-Sheng
authors.initials: YS
authors.lastname: Hu
authors.forename: Alison M
authors.initials: AM
authors.lastname: McDermott
mesh_terms: D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D019573:Epithelium, Corneal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
chemical_list: D016207:Cytokines; D007375:Interleukin-1