Elucidation of retinal degeneration mechanism due to lipid-mediated metabolic disorders

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K18854
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 56060:Ophthalmology-related
• Research Institution: Keio University
• Principal Investigator: Osada Hideto 慶應義塾大学, 医学部(信濃町), 研究員 (50748770)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: 網膜色素変性症

Outline of Final Research Achievements

Lipid metabolism-related gene mutations can cause retinitis pigmentosa, a currently untreatable blinding disease resulting from progressive neurodegeneration of the retina. Here, we demonstrated the influence of adiponectin receptor 1 (ADIPOR1) deficiency in lipid metabolism and retinal neurodegeneration using Adipor1 knockout (KO) mice. Photoreceptors of KO mice were misaligned and their lipid composition, including DHA, which is critical in forming photoreceptor outer segments, was impaired in the retina. Importantly, the expression of Elovl2, an elongase of very long chain fatty acids, was significantly reduced, and lipogenic genes, which are induced under conditions of reduced endogenous DHA synthesis, were increased in KO mice. Therefore, ADIPOR1 in the retina appears to be indispensable for ELOVL2 induction, which is likely required in the retinal local lipid metabolism to supply sufficient DHA for appropriate photoreceptor function and survival.

Free Research Field

眼科学

Academic Significance and Societal Importance of the Research Achievements

生活習慣病や臓器機能不全に由来する代謝異常は、糖尿病網膜症をはじめとする網膜の神経変性を引き起こすが、これらは不可逆的変化であり現状治療法はない。網膜は脂質を多量に含有し、形態や光受容体という機能の維持には脂肪酸が必須であることが示唆されている。本研究では網膜変性時の全身および網膜局所の脂質動態の変化を解析することにより、脂質代謝の異常に伴う網膜変性の発症メカニズムを検討した。全身性に変化する物質をとらえることはできなかったものの、網膜局所の脂質動態変化と新たな網膜変性の発生機構を示すことができた。