Abstract
Abstract: :
Purpose: PEDF shows potent neuroprotective and antiangiogenic actionsin the eye. We have used large–scale transcriptional profiling to detect molecular changes induced by PEDF on several retinal cells to determine how PEDF protects cells and control blood vessel growth in the eye. Methods: Primary cell cultures of mouse Müller glia were prepared and used between passages 3 and 6. Müller glial cells, Y–79 and A–RPE19 cell lines were adapted in medium containing 1% serum prior to treatment with 2 nM PEDF. We used the RNA from treated and untreated cells to prepare probes for hybridization to custom 9 K mouse retinal cDNA arrays or 8K human gene arrays (Clontech). After normalization and background subtraction, data from replicate arrays were averaged and the genes clustered into functional groups using gene array bioinformatic strategies. Results: Expression of most cellular genes was unaffected by PEDF indicating that its actions are focused on specific target genes. PEDF induced transcriptional changes fell into several functional categories including the regulation of genes that serve as protective agents for many stress responses, changes in genes associated with various aspects of the apoptotic pathway, modulation of several neurotrophic factors or their receptors, and regulation of genes involved in angiogenesis. We also noted fluctuation in the expression of specific genes after short (6 hr) and long (48 hr) PEDF treatments. Conclusions: This analysis has allowed us to draw the conclusion that the neurotrophic activities of PEDF are mediated by upregulation of specific protective genes and downregulation of pro–apoptotic genes while the antiangiogenic effect of PEDF may be linked to the downregulation of proangiogenic factors. There is also evidence that the actions of PEDF are cell type specific since PEDF induced changes in gene expression varied according to the target cells.
Keywords: neuroprotection • retinal degenerations: cell biology • gene microarray