テラワキ　セイゴウ   Seigo Terawaki   寺脇　正剛    所属   川崎医科大学  医学部 基礎医学　分子遺伝医学    職種   特任講師
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	Impaired lysosomal acidity maintenance in acid lipase-deficient cells leads to defective autophagy.
掲載誌名	正式名：The Journal of biological chemistry 略　 称：J Biol Chem ISSNコード：1083351X/00219258
掲載区分	国外
巻・号・頁	pp.105743
著者・共著者	Takahito Moriwaki, Seigo Terawaki, Takanobu Otomo
担当区分	2nd著者
発行年月	2024/02
概要	The lysosome is an acid organelle that contains a variety of hydrolytic enzymes and plays a significant role in intracellular degradation to maintain cellular homeostasis. Genetic variants in lysosome-related genes can lead to severe congenital diseases, such as lysosomal storage diseases. In the present study, we investigated the impact of depleting lysosomal acid lipase A (LIPA), a lysosomal esterase that metabolizes esterified cholesterol or triglyceride, on lysosomal function. Under nutrient-rich conditions, LIPA gene knockout (LIPAKO) cells exhibited impaired autophagy, whereas, under starved conditions, they showed normal autophagy. The cause underlying the differential autophagic activity was increased sensitivity of LIPAKO cells to ammonia which was produced from L-glutamine in the medium. Further investigation revealed that ammonia did not affect upstream signals involved in autophagy induction, autophagosome-lysosome fusion, and hydrolytic enzyme activities in LIPAKO cells. On the other hand, LIPAKO cells showed defective lysosomal acidity upon ammonia loading. Microscopic analyses revealed that lysosomes of LIPAKO cells enlarged, whereas the amount of lysosomal proton pump V-ATPase did not proportionally increase. Since the enlargement of lysosomes in LIPAKO cells was not normalized under starved conditions, this is the primary change that occurred in the LIPAKO cells, and autophagy was affected by impaired lysosomal function under the specific conditions. These findings expand our comprehension of the pathogenesis of Wolman's disease, which is caused by a defect in the LIPA gene, and suggest that conditions, such as hyperlipidemia, may easily disrupt lysosomal functions.
DOI	10.1016/j.jbc.2024.105743
PMID	38354786