线粒体电压依赖阴离子通道对携带线粒体DNA A4263G突变的细胞株线粒体钙循环的影响

Effect of voltage-dependent anion channel on the mitochondrial calcium cycle of cell lines carrying mitochondrial DNA A4263G mutation

目的研究线粒体外膜电压依赖阴离子通道(voltage-dependent anion channel,VDAC)在携带线粒体DNA(mitochondrial DNA,mtDNA)A4263G突变的细胞株线粒体钙循环中的作用。方法对该家系的4个母系成员(3个血压异常和1个血压正常者)和3名遗传背景相同的对照者建立了传代淋巴细胞系,利用共聚焦显微镜评价VDAC在携带mtDNA A4263G突变的高血压患者细胞线粒体钙循环中的作用。结果与正常对照者淋巴细胞比较,突变细胞株线粒体内钙荧光强度及线粒体膜电势(Δψm)降低,加入苍术苷(线粒体通道蛋白开放剂)后正常者线粒体内钙荧光强度增加,而突变携带者没有明显改变,但两者Δψm均降低,加入环孢素A(CsA)后可以抑制苍术苷作用。结论线粒体VDAC功能异常导致mtDNA A4263G突变携带者细胞线粒体对钙通透性增加,Δψ降低,加入苍术苷进一步导致Δψ降低,加入CsA后可以抑制苍术苷作用。

Objective To study the effect of voltage-dependent anion channel （VDAC） on the mitochondrial calcium cycle of the cell lines carrying mitochondrial DNA A4263G mutation. Methods Lymphoblastoid cell lines were established from 3 symptomatic and 1 asymptomatic individuals in the family carrying A4263G mutation when compared with 3 control cell lines. The mitochondrial calcium and potential was detected by confocal images. Results Confocal imagines showed the average Rhod-2 fluorescence and △ψm of individuals carrying tRNA^lle A4263G mutation was lower than that of control group ; the baseline of Rhod-2 fluorescence of the control group increased after exposure to atraetyloside （ opener of ANT, 5 μM） , but no significant change was tested on cell line from A4263G mutation. The △ψm decreased subsequently for both cell lines after exposure to atractyloside, while this effect of atractyloside was inhibited by VDAC blocker CsA （ 2 μM）. Conclusions The abnormality of mitochondrial VDAC leads to increase of mitochondrial permeability and decrease of potential cell lines carrying mtDNA A4263G mutations.