Abstract
Abstract: :
Purpose: Glaucoma is a leading cause of blindness worldwide. A major risk factor for glaucoma is increased intraocular pressure that leads to pathological changes in the optic nerve head (ONH). Astrocytes within the ONH become activated in glaucoma and may cause detrimental changes to retinal ganglion cell axons. The factors that may cause activation of the ONH are unknown. The purpose of the research was to determine if exogenous FGF–9, CNTF, and/or IL–1α activate human ONH astroctyes. Methods: Three human ONH astrocyte cell lines were grown until approximately 80% confluent and treated for 48 hours with either CNTF (150ng/mL), FGF– 9 (2ng/mL), or IL– 1α (2ng/mL) in serum–less media. Untreated cell lines acted as controls. RT–PCR was used to determine mRNA expression of CNTF, FGF– 9, and IL–1α, and their respective receptor complexes. Western Blot analysis was used to demonstrate the presence of CNTF, FGF–9, and IL–1α, their respective receptor complexes, and GFAP. Phase contrast microscopy was used to examine cell morphology. Proliferation assays was performed to demonstrate cell proliferation in response to exogenous CNTF, FGF–9, and IL–1α. Results: mRNA for CNTF, FGF–9, IL–1α and their receptor complexes is expressed by human ONH astrocytes. Protein expression for CNTF and its receptor gp130 and LIFR and IL–1 α and its receptor IL–1RI was obtained via western blots. Protein expression for FGF–9, FGFR1 and FGFR4 was observed but FGFR2 and FGFR3 was lacking. Exogenous IL–1α caused a significant increase in ONH astrocyte cell proliferation. Exogenous IL–1α caused human ONH astrocytes to extend more processes. Conclusions: These studies demonstrate that mRNA and protein for CNTF, FGF–9, and IL–1α and their respective receptors are expressed by human ONH astrocytes. In addition exogenous IL–1α caused morphological changes and increased proliferation. This research may help us understand the pathophysiology of the optic nerve head in glaucoma. CR: F(RJW); E(AFC). Support: NIH Grant EY12783 and Alcon Research Ltd., Fort Worth, TX.
Keywords: growth factors/growth factor receptors • lamina cribrosa • gene/expression