摘要
多聚谷氨酰胺(polyglutamine,polyQ)疾病是由CAG重复序列扩增突变引起的神经退行性疾病,其特征是polyQ突变蛋白聚集并引起细胞毒性.自噬是细胞内清除突变蛋白聚合体的主要机制之一.蛋白淀粉样变引起的神经退行性疾病中,氧自由基(reactive oxidative species,ROS)增加的同时往往伴随自噬功能障碍.利用抗氧化剂清除氧自由基在多种神经退行性疾病中表现出显著作用,其中,虾青素作为一种天然的抗氧化剂,具有多种抗氧化活性,能够有效防止脂质过氧化发生.利用稳定诱导表达polyQ突变蛋白的PC12神经细胞为模型,通过抗氧化剂的干预来研究polyQ突变蛋白的细胞毒性、自噬功能和氧化应激的关系.结果显示,在PC12细胞中,突变的polyQ蛋白在表达6 d后形成聚集体并促进ROS增加约17%,并随着表达时间的延长而进一步增加.抗氧化剂NAC(5 mmol/L)在降低ROS生成的同时,使polyQ聚集体水平下降约43%.氧自由基的清除能够有效改善自噬功能.与5 mmol/L NAC处理组相比,相同浓度(1μmol/L)的虾青素、花青素(氯化翠雀啶)、维生素E处理都能显著降低polyQ蛋白聚集体的形成,蛋白聚集体形成下降分别为67.9%、49.8%和27.6%,并伴随细胞活性的增强及自噬功能的改善.本研究表明polyQ突变蛋白扩增导致聚合体形成,细胞毒性增强;虾青素等抗氧化剂对降低polyQ突变蛋白诱导的细胞毒性表现出明显的改善效果,并对细胞自噬功能损伤起缓解作用,进而增强细胞活性;上述结果可为利用抗氧化剂尤其是虾青素作为缓解和治疗由polyQ突变引起的神经退行性疾病提供新的证据和支持.
Polyglutamine(polyQ)diseases are neurodegenerative diseases caused by mutations in CAG repeats,which encode proteins containing an expanded polyQ sequence.A common hallmark of polyQ diseases is the formation of mutant protein aggregates and subsequent induction of cytotoxicity.Autophagy is the predominant mechanism involved in the clearance of mutant proteins in eukaryotic cells.The elevation of reactive oxidative species(ROS)levels is generally accompanied by autophagic dysfunction in amyloid-induced neurodegenerative diseases.Astaxanthin,a natural antioxidant,shows various antioxidant activities that efficiently prevent lipid peroxidation.In our study,we used the PC12 neuronal cell model to stably express mutant proteins containing an expanded polyQ sequence,and our results showed that cytotoxicity,autophagic activity,and oxidative stress were all affected by antioxidants,especially astaxanthin.ATXN7 aggregation was detected after 6 days of induction,and ROS levels were elevated by approximately 17%in PC12 cells.Scavenging ROS by 5 mmol/L NAC ameliorated approximately 43%of total ROS,and the dysfunction of autophagy was recovered.Antioxidants,such as astaxanthin,delphinidin chloride,and vitamin E at the same concentration(1μmol/L)significantly scavenged ROS and counteracted protein misfolding at different levels compared to that in the control group(5 mM NAC).Astaxanthin,delphinidin chloride,and vitamin E significantly ameliorated polyQ mutant aggregation by 67.9%,49.8%,and 27.6%,respectively,accompanied by the recovery of both cell viability and autophagy.The expansion of polyQ resulted in the formation of mutant protein aggregates with enhanced cytotoxicity.Astaxanthin significantly counteracted cytotoxicity induced by mutant protein aggregation and recovered autophagy dysfunction.Our findings provide new evidence and support for the use of antioxidants,especially astaxanthin,as a potential supplementary material for the prevention and treatment of polyQ diseases.
作者
刘昊
陈超超
YU Xin
帅红艳
LIU Hao;CHEN Chaochao;YU Xin;SHUAI Hongyan(School of Basic Medical Sciences,Dali University,Dali 671000,China;Institute of Translational Medicine for Metabolic Diseases,Dali University,Dali 671000,China;Clinical College,Dali University,Dali 671000,China)
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2022年第1期215-221,共7页
Chinese Journal of Applied and Environmental Biology
基金
大理大学引进人才专项科研项目基金(KY1916103940)
云南省李云庆专家工作站项目资助。
