稀な遺伝子変異がアルツハイマー病に与える影響のメカニズム(Study explains how a rare gene variant contributes to Alzheimer’s disease)

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2025-09-10 マサチューセッツ工科大学(MIT)

MITの研究チームは、アルツハイマー病のリスクを高める希少遺伝子変異 ABCA7 の新たな作用機序を解明した。ABCA7は脂質を細胞膜間で輸送するタンパク質をコードするが、変異により脂質代謝が乱れ、神経細胞の膜が硬化、ミトコンドリアの膜電位調節が障害され、酸化ストレスとDNA損傷を引き起こす。その結果、神経細胞は過剰に興奮し、アミロイドβの蓄積が促進される。研究では、ヒトiPS細胞由来ニューロンやオルガノイドを用いて検証し、前駆体物質 CDP-コリン 投与により膜機能が回復、酸化ストレスとアミロイドβ蓄積が抑制されることを発見した。この知見は、既にAPOE4変異でも効果が示唆されており、臨床試験への展開も進行中。成果は Nature に発表され、コリン摂取の栄養学的介入がアルツハイマー病予防につながる可能性を示す。

稀な遺伝子変異がアルツハイマー病に与える影響のメカニズム(Study explains how a rare gene variant contributes to Alzheimer’s disease)
In the Alzheimer’s affected brain, abnormal levels of the beta-amyloid protein clump together to form plaques (seen in brown) that collect between neurons and disrupt cell function. Abnormal collections of the tau protein accumulate and form tangles (seen in blue) within neurons, harming synaptic communication between nerve cells.
Credit: National Institute on Aging, NIH

<関連情報>

ABCA7変異体は神経細胞内のホスファチジルコリンとミトコンドリアに影響を与える ABCA7 variants impact phosphatidylcholine and mitochondria in neurons

Djuna von Maydell,Shannon E. Wright,Ping-Chieh Pao,Colin Staab,Oisín King,Andrea Spitaleri,Julia Maeve Bonner,Liwang Liu,Chung Jong Yu,Ching-Chi Chiu,Daniel Leible,Aine Ni Scannail,Mingpei Li,Carles A. Boix,Hansruedi Mathys,Guillaume Leclerc,Gloria Suella Menchaca,Gwyneth Welch,Agnese Graziosi,Noelle Leary,George Samaan,Manolis Kellis & Li-Huei Tsai
Nature  Published:10 September 2025
DOI:https://doi.org/10.1038/s41586-025-09520-y

Abstract

Loss-of-function variants in the lipid transporter ABCA7 substantially increase the risk of Alzheimer’s disease1,2, yet how they impact cellular states to drive disease remains unclear. Here, using single-nucleus RNA-sequencing analysis of human brain samples, we identified widespread gene expression changes across multiple neural cell types associated with rare ABCA7 loss-of-function variants. Excitatory neurons, which expressed the highest levels of ABCA7, showed disrupted lipid metabolism, mitochondrial function, DNA repair and synaptic signalling pathways. Similar transcriptional disruptions occurred in neurons carrying the common Alzheimer’s-associated variant ABCA7 p.Ala1527Gly3, predicted by molecular dynamics simulations to alter the ABCA7 structure. Induced pluripotent stem (iPS)-cell-derived neurons with ABCA7 loss-of-function variants recapitulated these transcriptional changes, displaying impaired mitochondrial function, increased oxidative stress and disrupted phosphatidylcholine metabolism. Supplementation with CDP-choline increased phosphatidylcholine synthesis, reversed these abnormalities and normalized amyloid-β secretion and neuronal hyperexcitability—key Alzheimer’s features that are exacerbated by ABCA7 dysfunction. Our results implicate disrupted phosphatidylcholine metabolism in ABCA7-related Alzheimer’s risk and highlight a possible therapeutic approach.

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