中文摘要
白癜风是由于皮肤黑素细胞减少或丧失所致的色素脱失性疾病,易诊断,难治疗,对患者生活、社交造成严重影响。本病病因不清,目前认为氧化损伤是重要发病机制。线粒体是细胞内对氧化损伤最敏感的细胞器,线粒体稳态破坏是细胞整体氧化损伤发生的始动因素。DJ-1蛋白在多巴胺能神经元的氧化损伤中起到保护作用,是帕金森病发病机制中的重要保护因子,但其在白癜风氧化损伤中的作用尚未见深入研究。本研究通过建立黑素细胞的氧化应激模型,动态观察氧化应激下DJ-1蛋白在细胞内的移位;并采用小发卡RNA基因沉默和质粒转染技术上调或下调DJ-1的表达,观察氧化应激下DJ-1不同表达水平对线粒体稳态(形态、结构、膜通透性、分裂融合、线粒体DNA)、细胞内ROS水平、细胞凋亡的影响,探讨其发挥保护作用的机制,为完善白癜风发病机制、开发潜在的治疗手段提供科学的理论依据。
英文摘要
Vitiligo is a depigmenting disorder caused by reduction or loss of melanocyte in the skin. Vitiligo is easy to diagnose, but difficult to treat, and it can cause negative impact on social life. The etiology of vitiligo is still unkown, oxidative damage has been recognized as an important pathogenesis. Mitochondria is very sensitive to oxidative stress, the break of mitochondrial homeostasis was the initiating factor to the whole cell damage against oxidative stress.The DJ-1 protein has been confirmed to have protective effect in dopaminergic neurons against oxidative damage, and it is an important protective factor in the pathogenesis of Parkinson's disease. But the role of DJ-1 protein in oxidative damage in vitiligo has not been studied. In this study, we will establish the melanocyte oxidative stress model, observe the subcellular location and translocation of DJ-1 protein in melanocyte. Using short hairpin RNA gene silencing and plasmid transfection to make DJ-1 gene silenced and overexpressed, observe the change of mitochondrial homeostasis(morphology, membrane permeability, fission/ fusion and mtDNA), intracellular ROS level and cell apoptosis. We hope that this research may provide new insight to vitiligo's pathogenesis and treatment.
结题摘要
白癜风是常见的色素脱失性皮肤病,体内氧化-抗氧化系统失衡,导致活性氧簇蓄积是造成黑素细胞损伤的重要原因之一。DJ-1蛋白在神经细胞等多种组织内都有表达,研究发现DJ-1蛋白在细胞的氧化损伤中具有“保护作用”,但是其在黑素细胞中是否也具有保护作用尚未见报道。我们首先采用实时定量RT-PCR和Western-blot在mRNA和蛋白水平证实DJ-1在人黑素细胞系PIG1中有表达。然后利用小干扰RNA技术(siRNA)下调DJ-1在PIG1中的表达,实验分组为Mock组(只加入转染试剂)、NC组(阴性对照)和siRNA组(siRNA干扰),过氧化氢处理12-24小时后使用光学显微镜和电子显微镜观察细胞的形态学及微观结构的变化,测定细胞活力和细胞凋亡,测定细胞内ROS的水平和线粒体膜电位的变化。结果显示,与Mock组和NC组相比,siRNA组在在氧化损伤后漂浮的死亡细胞明显增多;在电镜下细胞吞噬囊泡的数量增加,且线粒体形态明显异常;细胞活力明显下降,细胞凋亡比例显著增加,与形态学的结果一致。同时siRNA组细胞内ROS水平增加,线粒体膜电位下降,以上差异均具有统计学意义。本研究首次在人黑素细胞中证实了DJ-1蛋白的表达,证实下调DJ-1的表达会使黑素细胞更易受到氧化损伤,并使黑素细胞内活性氧簇蓄积,线粒体膜电位下降。这一发现对白癜风的发病机制有了新的补充,为白癜风的治疗提供了新的思路和靶点。
