Mitochondrial DNMT3A and DNA methylation in skeletal muscle and CNS of transgenic mouse models of ALS.
Mitochondrial DNMT3A and DNA methylation in skeletal muscle and CNS of transgenic mouse models of ALS.
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DOI：
10.3389/fncel.2013.00279
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发表时间：
2013
影响因子：
5.3
通讯作者：
Martin LJ
中科院分区：
文献类型：
--
作者：
Wong M;Gertz B;Chestnut BA;Martin LJ
胞嘧啶甲基化是由DNA甲基转移酶催化的DNA表观遗传修饰。线粒体DNA（mtDNA）的胞嘧啶甲基化被认为具有相对低的代表性;然而，尚未检查mtDNA甲基化的可能组织和细胞差异以及与神经退行性疾病的关系。我们通过免疫印迹表明，DNA甲基转移酶3A（Dnmt 3a）亚型存在于成年小鼠中枢神经系统，骨骼肌，睾丸和成年人大脑皮层的纯线粒体。在成年小鼠CNS或骨骼肌线粒体中未检测到Dnmt 1，但似乎与线粒体外膜结合。免疫荧光证实了Dnmt 3a的线粒体定位，并显示5-甲基胞嘧啶（5 mC）的免疫反应在神经元和骨骼肌肌纤维的线粒体。对线粒体DNA中的两个位点（D-loop和16 SrRNA基因）和12个胞嘧啶磷酸鸟嘌呤（cytosine-phosphate-guanine，CpG）位点的DNA焦磷酸测序直接显示了5 mC的组织差异存在。由于线粒体参与了肌萎缩侧索硬化症（ALS）的发病机制，但疾病的机制尚不确定，我们评估了人超氧化物歧化酶-1（SOD 1）转基因ALS小鼠模型中线粒体Dnmt 3a和5 mC水平。在症状前或疾病早期，骨骼肌和脊髓中线粒体Dnmt 3a蛋白水平显著降低。免疫荧光显示，ALS小鼠神经元和骨骼肌肌纤维的线粒体中存在5 mC免疫反应阳性物质，运动神经元中5 mC免疫反应阳性物质聚集。DNA焦磷酸测序显示ALS小鼠16 S rRNA基因甲基化存在显著异常。免疫荧光显示，5 mC免疫反应可以被隔离到自噬体中，并且ALS小鼠骨骼肌中的线粒体自噬增加，线粒体含量减少。本研究揭示了Dnmt 3a的组织优先线粒体定位和神经组织和骨骼肌的mtDNA中胞嘧啶甲基化的存在，并证明了在症状前ALS小鼠的骨骼肌和脊髓中mtDNA甲基化模式和线粒体Dnmt 3a水平是异常的，并且这些异常与肌纤维线粒体的损失平行发生。
Cytosine methylation is an epigenetic modification of DNA catalyzed by DNA methyltransferases. Cytosine methylation of mitochondrial DNA (mtDNA) is believed to have relative underrepresentation; however, possible tissue and cell differences in mtDNA methylation and relationships to neurodegenerative disease have not been examined. We show by immunoblotting that DNA methyltransferase 3A (Dnmt3a) isoform is present in pure mitochondria of adult mouse CNS, skeletal muscle, and testes, and adult human cerebral cortex. Dnmt1 was not detected in adult mouse CNS or skeletal muscle mitochondria but appeared bound to the outer mitochondrial membrane. Immunofluorescence confirmed the mitochondrial localization of Dnmt3a and showed 5-methylcytosine (5mC) immunoreactivity in mitochondria of neurons and skeletal muscle myofibers. DNA pyrosequencing of two loci (D-loop and 16S rRNA gene) and twelve cytosine-phosphate-guanine (CpG) sites in mtDNA directly showed a tissue differential presence of 5mC. Because mitochondria have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS), but the disease mechanisms are uncertain, we evaluated mitochondrial Dnmt3a and 5mC levels in human superoxide dismutase-1 (SOD1) transgenic mouse models of ALS. Mitochondrial Dnmt3a protein levels were reduced significantly in skeletal muscle and spinal cord at presymptomatic or early disease. Immunofluorescence showed that 5mC immunoreactivity was present in mitochondria of neurons and skeletal myofibers, and 5mC immunoreactivity became aggregated in motor neurons of ALS mice. DNA pyrosequencing revealed significant abnormalities in 16S rRNA gene methylation in ALS mice. Immunofluorescence showed that 5mC immunoreactivity can be sequestered into autophagosomes and that mitophagy was increased and mitochondrial content was decreased in skeletal muscle in ALS mice. This study reveals a tissue-preferential mitochondrial localization of Dnmt3a and presence of cytosine methylation in mtDNA of nervous tissue and skeletal muscle and demonstrates that mtDNA methylation patterns and mitochondrial Dnmt3a levels are abnormal in skeletal muscle and spinal cord of presymptomatic ALS mice, and these abnormalities occur in parallel with loss of myofiber mitochondria.
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影响因子：
4.8
作者：
Carré, M;André, N;Braguer, D
通讯作者：
Braguer, D
DOI：
10.1097/nen.0b013e318244b635
发表时间：
2012-02
影响因子：
3.2
作者：
Gertz B;Wong M;Martin LJ
通讯作者：
Martin LJ
影响因子：
4.4
作者：
Corti, Stefania;Donadoni, Chiara;Comi, Giacomo P.
通讯作者：
Comi, Giacomo P.
影响因子：
3.1
作者：
Chen, Kevin;Northington, Frances J.;Martin, Lee J.
通讯作者：
Martin, Lee J.
影响因子：
3.7
作者：
Corcia P;Tauber C;Vercoullie J;Arlicot N;Prunier C;Praline J;Nicolas G;Venel Y;Hommet C;Baulieu JL;Cottier JP;Roussel C;Kassiou M;Guilloteau D;Ribeiro MJ
通讯作者：
Ribeiro MJ