TISSUE CULTURE MODEL FOR RETINITIS PIGMENTOSA--A MOLECULAR APPROACH

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More than half of the thousands of Americans who become blind each year are diagnosed as having a genetic defect. Ocular diseases in which retinal pigment epithelium (PE) is implicated are retinitis pigmentosa (RP), gyrate atrophy, choroidemia, choroidal sclerosis, and Stargedt's macular degeneration. The long-term goal of this project is to identify and characterize the genetic defect and/or defects in ocular diseases broadly grouped as retinitis pigmentosa (RP). Retinitis pigmentosa is a degenerative retinal disease characterized by eventual loss of photoreceptor cells. Studies on normal and dystrophic animal models suggest that visual failure in RP may be secondary to dysfunction in the retina and pigment epithelium (PE). Although RP is the commonest occurring retinal degenerative disease, the information on etiology and mechanism of pathogenesis in disease is both scant and confusing. Deficiencies in available information could be singularly related to inadequate availability of biological tissues. Primary explant cultures of PE, retina have a finite lifespan and a few permanent cell lines are dedifferentiated. As such they are not an optimal model for the study of retinal degeneration. The goal of this proposal is to pursue an alternate approach and establish ocular cell lines from normal and RP donor eyes (autosomal recessive, autosomal dominant and sex linked) by use of a variety of protooncogenes and viral DNAs (H-ras - (Val 12) v- myc, SV-40 viral DNA and SV-40T antigen gene. We have already established a variety of normal PE cell lines by use of protooncogenes (see Appendix) and have also been able to obtain more differentiated spontaneously established cell lines by use of extracellular matrices (see Appendix). In this study period, we propose to establish retinal cell lines from RP donors and compare the normal immortal cell lines with RP cell lines for growth, morphology and expression of PE - functional markers like phagocytosis of rod outer segments and retinal metabolism. We will also explore the role of growth factors and chemical inducers in photoreceptor cell differentiation as RP is ultimately a disease of photoreceptor cell degeneration. The long-term goal will be to identify and correct the lesion in RP by using this tissue culture approach.