The mitochondrial calcium uniporter is involved in mitochondrial calcium cycle dysfunction: Underlying mechanism of hypertension associated with mitochondrial tRNA^Ile A4263G mutation

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• 作者：Xi Chen¹ ; Yu Zhang¹ ; Bin Xu¹ ; Zhongqi Cai ; Lin Wang ; Jinwen Tian ; Yuqi Liu ; ^{ametuofo980869@163.com" class="auth_mail" title="E-mail the corresponding author} ; Yang Li ; ^{liyangbsh@163.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Mitochondrial calcium uniporter ; Mitochondrial calcium cycle ; Hypertension ; tRNA mutation
• 刊名：International Journal of Biochemistry and Cell Biology
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：78
• 期：Complete
• 页码：307-314
• 全文大小：1722 K

文摘

Recent studies have shown that the mitochondrial DNA mutations are involved in the pathogenesis of hypertension. Our previous study identified mitochondrial tRNA^Ile A4263G mutation in a large Chinese Han family with maternally-inherited hypertension. This mutation may contribute to mitochondrial Ca²⁺ cycling dysfuntion, but the mechanism is unclear. Lymphoblastoid cell lines were derived from hypertensive and normotensive individuals, either with or without tRNA^Ile A4263G mutation. The mitochondrial calcium ([Ca²⁺]_m) in cells from hypertensive subjects with the tRNA^Ile A4263G mutation, was lower than in cells from normotension or hypertension without mutation, or normotension with mutation (P < 0.05). Meanwhile, cytosolic calcium ([Ca²⁺]_c) in hypertensive with mutation cells was higher than another three groups. After exposure to caffeine, which could increase the [Ca²⁺]_c by activating ryanodine receptor on endoplasmic reticulum, [Ca²⁺]_c/[Ca²⁺]_m increased higher than in hypertensive with mutation cells from another three groups. Moreover, MCU expression was decreased in hypertensive with mutation cells compared with in another three groups (P < 0.05). [Ca²⁺]_c increased and [Ca²⁺]_m decreased after treatment with Ru360 (an inhibitor of MCU) or an siRNA against MCU. In this study we found decreased MCU expression in hypertensive with mutation cells contributed to dysregulated Ca²⁺ uptake into the mitochondria, and cytoplasmic Ca²⁺ overload. This abnormality might be involved in the underlying mechanisms of maternally inherited hypertension in subjects carrying the mitochondrial tRNA^Ile A4263G mutation.