Department of Biological Sciences, Southern Methodist University, Dallas, TX, USA.
Department of Biological Sciences, Southern Methodist University, Dallas, TX, USA.
Biochim Biophys Acta Mol Basis Dis. 2017 Jan;1863(1):68-80. doi: 10.1016/j.bbadis.2016.10.017. Epub 2016 Oct 19.
Previously, we have shown that flies under-expressing the two mitochondrial peroxiredoxins (Prxs), dPrx3 and dPrx5, display increases in tissue-specific apoptosis and dramatically shortened life span, associated with a redox crisis, manifested as changes in GSH:GSSG and accumulation of protein mixed disulfides. To identify specific pathways responsible for the observed biological effects, we performed a transcriptome analysis. Functional clustering revealed a prominent group enriched for immunity-related genes, including a considerable number of NF-kB-dependent antimicrobial peptides (AMP) that are up-regulated in the Prx double mutant. Using qRT-PCR analysis we determined that the age-dependent changes in AMP levels in mutant flies were similar to those observed in controls when scaled to percentage of life span. To further clarify the role of Prx-dependent mitochondrial signaling, we expressed different forms of dPrx5, which unlike the uniquely mitochondrial dPrx3 is found in multiple subcellular compartments, including mitochondrion, nucleus and cytosol. Ectopic expression of dPrx5 in mitochondria but not nucleus or cytosol partially extended longevity under normal or oxidative stress conditions while complete restoration of life span occurred when all three forms of dPrx5 were expressed from the wild type dPrx5 transgene. When dPrx5 was expressed in mitochondria or in all three compartments, it substantially delayed the development of hyperactive immunity while expression of cytosolic or nuclear forms had no effect on the immune phenotype. The data suggest a critical role of mitochondria in development of chronic activation of the immune response triggered by impaired redox control.
先前，我们已经证明，表达量下调的两种线粒体过氧化物酶（Prx），dPrx3 和 dPrx5，会导致组织特异性细胞凋亡增加和寿命显著缩短，这与氧化还原危机有关，表现为 GSH:GSSG 的变化和蛋白质混合二硫键的积累。为了鉴定负责观察到的生物学效应的特定途径，我们进行了转录组分析。功能聚类显示了一个富含与免疫相关基因的显著群体，包括大量 NF-κB 依赖性抗菌肽（AMP），在 Prx 双突变体中上调。使用 qRT-PCR 分析，我们确定了突变体果蝇中 AMP 水平的年龄依赖性变化与对照果蝇相似，当按寿命百分比进行归一化时。为了进一步阐明 Prx 依赖性线粒体信号的作用，我们表达了不同形式的 dPrx5，与独特存在于线粒体中的 dPrx3 不同，dPrx5 存在于多种亚细胞区室中，包括线粒体、核和细胞质。dPrx5 在线粒体中的异位表达，而不是在核或细胞质中，部分延长了正常或氧化应激条件下的寿命，而当从野生型 dPrx5 转基因表达所有三种形式的 dPrx5 时，完全恢复了寿命。当 dPrx5 在线粒体或所有三个区室中表达时，它大大延迟了过度活跃的免疫的发展，而细胞质或核形式的表达对免疫表型没有影响。数据表明，线粒体在由氧化还原控制受损引发的慢性激活免疫反应的发展中起着关键作用。
