| Budget Amount *help |
¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2014: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Outline of Final Research Achievements |
Prosaposin (PSAP) is a precursor protein of four saposins, which are required for the intra lysosomal degradation of sphingolipids, and is also secreted into extra-cellular space as a trophic factor. The deficiency of semaphorin 4A (Sema4A), were reported to cause photoreceptor cell degeneration due to the impaired secretion of PSAP from the retinal pigment epithelial cells (RPE). In the present study, we characterized the retinal phenotypes of Psap knock-out (Psap-KO) mice and PSAP transgenic (PSAP-Tg) mice which have strong, stable, and ubiquitous expression of PSAP. In the retinas of Psap-KO mice, no apparent photoreceptor cell degeneration were observed.In contrast, in the retinas of PSAP-Tg mice, almost all the photoreceptor cells were disappeared by 6 weeks of age. These findings indicate that PSAP and SAPs play a critical role in retina, and intra-cellular accumulation of PSAP and SAPs cause retinal photoreceptor cell degeneration.
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