阿尔茨海默病转线粒体DNA细胞模型胞质钙稳态的改变

Alteration of Cytosolic Calcium in mtDNA-transferred Cells of Alzheimer's Disease

目的观察阿尔茨海默病(Alzheimer's disease,AD)转线粒体DNA细胞模型胞质游离钙水平,探讨线粒体DNA(mitochondrial DNA,mtDNA)缺陷在AD发病中的作用。方法 将正常青年人、正常老年人和AD患者的血小板分别与无mtDNA细胞融合,建立转mtDNA细胞模型。采用微测量法测定细胞色素C氧化酶(cytochrome C oxidase,COX)的活性;用荧光探针Fluo-3标记胞质内游离钙离子,激光共聚焦显微镜和流式细胞仪观察细胞胞质钙离子荧光强度。结果 AD转mtDNA细胞COX活性与正常老年对照相比差异有统计学意义(P<0.05);静息状态胞质钙离子浓度升高,氧化磷酸化解耦联剂CCCP刺激后胞质钙离子的调节能力明显降低。结论 AD患者线粒体存在COX缺陷,使线粒体钙库功能下降,导致细胞内胞质钙稳态失衡。

Objective：To investigate the level of cytosolic free calcium in mitochondria DNA-transferred cells of Alzheimer＇s disease and the influence of mitochondrial DNA（mtDNA） deficiency on calcium regulation capacity of cells.Methods：Platelets from AD patients and aged control persons were fused with mtDNA-depleted cells to develop mtDNA-transferred cell model.Cytochrome C oxidase（COX） activity was determined by microplate assay;cytosolic calcium was labeled with Fluo-3 and fluorescence density was detected with laser scan confocal microscope（LSCM） and flow cytometer（FCM）.Results：COX activity was reduced in AD mtDNA-transferred cells when compared with aged control and young control.The resting cytosolic calcium was elevated in AD mtDNA-transferred cells compared with the controls and decreased when stimulated by carbonyl cyanide m-chlorophenyl hydrazone（CCCP）.Conclusion：The transfer of AD mtDNA was sufficient to produce pathological changes in cytosolic calcium regulation.