Dataset Information

A Hypertension-Associated tRNAAla Mutation Alters tRNA Metabolism and Mitochondrial Function.

ABSTRACT: In this report, we investigated the pathophysiology of a novel hypertension-associated mitochondrial tRNA(Ala) 5655A ? G (m.5655A ? G) mutation. The destabilization of a highly conserved base pairing (A1-U72) at the aminoacyl acceptor stem by an m.5655A ? G mutation altered the tRNA(Ala) function. An in vitro processing analysis showed that the m.5655A ? G mutation reduced the efficiency of tRNA(Ala) precursor 5' end cleavage catalyzed by RNase P. By using cybrids constructed by transferring mitochondria from lymphoblastoid cell lines derived from a Chinese family into mitochondrial DNA (mtDNA)-less (?(o)) cells, we showed a 41% reduction in the steady-state level of tRNA(Ala) in mutant cybrids. The mutation caused an improperly aminoacylated tRNA(Ala), as suggested by aberrantly aminoacylated tRNA(Ala) and slower electrophoretic mobility of mutated tRNA. A failure in tRNA(Ala) metabolism contributed to variable reductions in six mtDNA-encoded polypeptides in mutant cells, ranging from 21% to 37.5%, with an average of a 29.1% reduction, compared to levels of the controls. The impaired translation caused reduced activities of mitochondrial respiration chains. Furthermore, marked decreases in the levels of mitochondrial ATP and membrane potential were observed in mutant cells. These caused increases in the production of reactive oxygen species in the mutant cybrids. The data provide evidence for the association of the tRNA(Ala) 5655A ? G mutation with hypertension.

SUBMITTER: Jiang P

PROVIDER: S-EPMC4936059 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

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A Hypertension-Associated tRNAAla Mutation Alters tRNA Metabolism and Mitochondrial Function.

Jiang Pingping P Wang Meng M Xue Ling L Xiao Yun Y Yu Jialing J Wang Hui H Yao Juan J Liu Hao H Peng Yanyan Y Liu Hanqing H Li Haiying H Chen Ye Y Guan Min-Xin MX

Molecular and cellular biology 20160629 14

In this report, we investigated the pathophysiology of a novel hypertension-associated mitochondrial tRNA(Ala) 5655A → G (m.5655A → G) mutation. The destabilization of a highly conserved base pairing (A1-U72) at the aminoacyl acceptor stem by an m.5655A → G mutation altered the tRNA(Ala) function. An in vitro processing analysis showed that the m.5655A → G mutation reduced the efficiency of tRNA(Ala) precursor 5' end cleavage catalyzed by RNase P. By using cybrids constructed by transferring mit ...[more]

PMID: 27161322

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Project description:The deafness-associated m.12201T>C mutation affects the A5-U68 base-pairing within the acceptor stem of mitochondrial tRNAHis The primary defect in this mutation is an alteration in tRNAHis aminoacylation. Here, we further investigate the molecular mechanism of the deafness-associated tRNAHis 12201T>C mutation and test whether the overexpression of the human mitochondrial histidyl-tRNA synthetase gene (HARS2) in cytoplasmic hybrid (cybrid) cells carrying the m.12201T>C mutation reverses mitochondrial dysfunctions. Using molecular dynamics simulations, we demonstrate that the m.12201T>C mutation perturbs the tRNAHis structure and function, supported by decreased melting temperature, conformational changes, and instability of mutated tRNA. We show that the m.12201T>C mutation-induced alteration of aminoacylation tRNAHis causes mitochondrial translational defects and respiratory deficiency. We found that the transfer of HARS2 into the cybrids carrying the m.12201T>C mutation raises the levels of aminoacylated tRNAHis from 56.3 to 75.0% but does not change the aminoacylation of other tRNAs. Strikingly, HARS2 overexpression increased the steady-state levels of tRNAHis and of noncognate tRNAs, including tRNAAla, tRNAGln, tRNAGlu, tRNALeu(UUR), tRNALys, and tRNAMet, in cells bearing the m.12201T>C mutation. This improved tRNA metabolism elevated the efficiency of mitochondrial translation, activities of oxidative phosphorylation complexes, and respiration capacity. Furthermore, HARS2 overexpression markedly increased mitochondrial ATP levels and membrane potential and reduced production of reactive oxygen species in cells carrying the m.12201T>C mutation. These results indicate that HARS2 overexpression corrects the mitochondrial dysfunction caused by the tRNAHis mutation. These findings provide critical insights into the pathophysiology of mitochondrial disease and represent a step toward improved therapeutic interventions for mitochondrial disorders.

Dataset Information

A Hypertension-Associated tRNAAla Mutation Alters tRNA Metabolism and Mitochondrial Function.

Publications

A Hypertension-Associated tRNAAla Mutation Alters tRNA Metabolism and Mitochondrial Function.

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