Abstract
This work aims to investigate the effect of compromised lysosomal enzyme activity on the accumulation of photoreceptor-derived debris in the retinal pigment epithelial (RPE) cells and to examine if this accelerated debris accumulation can induce retinal abnormalities similar to those observed in aged individuals. A mutated, enzymatically inactive form of cathepsin D (CatD), generated by site-directed mutagenesis was used to produce stable cell lines and transgenic mice. There was a strong increase in enzymatically inactive CatD protein production in the mutated CatD DNA transfected D407 cells (D407MCD). The presence of the inactive CatD has been linked to an impairment in bovine rod outer segment(BROS) digestion and was confirmed by astatistically significant increase of undigested residual BROS in the medium ofD407MCD when compared to the control vector-transfected D407 cells (t-test,P ≤ 0.016, P ≤ 0.003) or untransfectedD407 cells (t-test, P ≤ 0.008,P ≤ 0.003). The impairment was also confirmed in vivo by demonstration of BROS-derived debris accumulation in the RPE cell layer of transgenic mice. These results demonstrated that the mutated and inactive CatD form could lead to impairment of photo receptorouter segments (POS) proteolysis. It is proposed that this initial impairment of POS proteolysis may result in the accumulation of CatD-opsin-like complexes in the pigment epithelium, which further compromises RPE cell functions and thus causes the changes observed in aging humans.
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Augereau P, GarciaM, Mattei MG, Cavailles V, Depadova F, Derocq D, Capony F, Ferrara P and Rochefort H (1988) Cloning and sequencing of the 52K cathepsin complementary deoxyribonucleic acid of MCF7 breast cancer cells and mapping on chromosome 11. Mol Endocrinol 2: 186-192
Bok D (1993) The retinal pigment epithelium: a versatile partner in vision. J Cell Sci 17: 189-195
Boulton M, McKechnie NM, Breda J, Bayly M and Marshall J (1989) The formation of autofluorescent granules in cultured human RPE. Invest Ophthalmol Vis Sci 30: 82-89
Bressler NM, Bressler SB, West SK, Fine SL and Taylor HR (1989) The grading and prevalence of macular degeneration in Chesapeake Bay watermen. Arch Ophthalmol 107: 847-852
Davies DR (1990) The structure and function of the aspartic proteinases. Annu Rev Biophys Biophys Chem 19: 189-215
Erickson AH, Blobel G and Conner GE (1981) Biosynthesis of a lysosomal enzyme partial structure of two transient and functionally distinct NH2-terminal sequences in cathepsin D. J Biol Chem 256: 11224-11231
Faust PL, Kornfeld S and Chirgwin JM (1985) Cloning and sequence analysis of cDNA for human cathepsin D. Proc Natl Acad Sci USA 82: 4910-4914
Gass JDM (1973) Drusen and disciform macular detachment and degeneration. Arch Ophthalmol 90: 206-217
Green WR and Enger C (1993) Age-related macular degeneration histopathologic studies. The 1992 Lorenz E. Zimmerman Lecture. Ophthalmol 100: 1519-1535
Huang JS, Huang SS and Tang J (1979) Cathepsin D isozymes from porcine spleens. J Biol Chem 254: 11405-11417
Klein R, Klein BEK and Linton KLP (1992) Prevalence of agerelated maculopathy. The beaver Dam Eye Study. Ophthalmol 99: 933-934
Lee AY, Gulnik SV and Erickson JW (1998) Conformational switching in an aspartic proteinase. Nature Structural Biology 5: 866-871
Mitchell P, Smith W, Attebo K and Wang JJ (1995) Prevalence of age-related maculopathy in Australia. Ophthalmol 102: 1450-1460
Pauleikhoff D, Barondes MJ, Minassian D, Chrisholm IH and Bird AC (1990) Drusen as risk factors in age-related macular disease. Am J Ophthalmol 109: 38-43
Rakoczy PE, Lai CM, Baines M, Di Grandi S, Fitton JH and Constable IJ (1997) Modulation of cathepsin D activity in retinal pigment epithelial cells. Biochem J 324: 935-940
Rakoczy P, Lai M, Vijayasekaran S, Robertson T, Rapp L, Papadimitriou J and Constable I (1996) Initiation of impaired outer segment degradation in vivo using an antisense oligonucleotide. Curr Eye Res 15: 119-123
Rakoczy, PE, Sarks S, Daw N and Constable IJ (1999) Distrabution of cathepsin D in human eyes with or without age-related maculopathy. Exp Eye Res 69: 367-374
Regan CM, De Grip WJ, Daemen FJM and Bonting SL (1980) Degeneration of rhodopsin by a lysosomal fraction of retinal pigment epithelium: biochemical aspects of the visual process. Exp Eye Res 30: 183-191
Safting P, Hetman M, Schmahl W, Weber K, Heine L, Mossmann H, Koster A, Hess B, Evers M, von Figura P and Peters C (1995) Mice deficient for the lysosomal proteinase cathepsin D exhibit progressive atrophy of the intestinal mucosa and profound destruction of lymphoid cells. EMBO J 14: 3599-3608
Sarks SH (1976) Aging and degeneration in the macular region: a clinico-pathological study. Br Ophthalmol 60: 324-341
Sparrow JR, Parish CA, Hashimoto Mand Nakanishi K (1999) A2E, a lipofuscin fluorophore, in human retinal pigment epithelial cells in culture. Invest Ophthalmol Vis Sci 40: 2988-2995
Vingerling JR, Dielemans I, Hofman A, Grobbee DE, Hilmering M, Kramer CFL and de Jong PTVM (1995) The Prevalence of agerelated maculopathy in the Rotterdam study. Ophthalmol 102: 205-210
Weiter JJ, Delori FC, Wing GL and Fitch KA (1986) Retinal pigment epithelial lipofuscin and melanin and choroidal melanin in human eyes. Invest Ophthalmol Vis Sci 27: 145-152
Wiederanders B and Oelke B (1984) Accumulation of inactive cathepsin D in old rats. Mech Ageing Dev 24: 265-271
Wilcox DK (1988) Vectorial accumulation of cathepsin D in retinal pigment epithelium: effects of age. Invest Ophthalmol Vis Sci 29: 1205-1212
Young RW (1987) Pathophysiology of age-related macular degeneration. Surv Ophthalmol 31: 291-306
Young RW and Bok D (1969) Participation of the retinal pigment epithelium in the rod outer segment renewal process. J Cell Biol 42: 392-403
Zhang D, Lai CM, Constable IJ and Rakoczy PE (2000) A novel immunoassay for the evaluation of rod outer segment digestion in cultured retinal pigment epithelial cells. Clinical Exp Ophthalmol 28: 216-219
Zimmerman WF, Godchaux III Wand Belkin M (1983) The relative proportions of lysosomal enzyme activities in bovine retinal pigment epithelium. Exp Eye Res 36: 151-158
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Zhang, D., Lai, M.C., Constable, I.J. et al. A model for a blinding eye disease of the aged. Biogerontology 3, 61–66 (2002). https://doi.org/10.1023/A:1015259413857
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DOI: https://doi.org/10.1023/A:1015259413857