摘要
目的：检测唐氏综合症（DS）患者脑组织中αB-晶状蛋白及其Ser59和Ser45磷酸化形式的表达及分布,探讨αB-晶状蛋白发生磷酸化的程度对唐氏综合症患者脑损伤的意义。方法：收集11例4个月~17岁大的DS患者和5例5个月~23岁大的正常对照者脑组织石蜡标本,以及12例9个月~23岁大的正常对照者冰冻脑组织及12例6个月~23岁DS患者冰冻脑组织,通过Western blot技术检测αB-晶状蛋白及其Ser59和Ser45磷酸化形式在脑前额皮层及白质中的表达。采用免疫荧光共聚焦双染及三染技术检测αB-晶状蛋白在脑组织中的定位。结果：αB-晶状蛋白及其Ser59磷酸化形式在DS患者婴幼儿期即可被检测到,但其Ser45磷酸化形式仅能在青少年期被检测到,且表达量较低。αB-晶状蛋白及其两种磷酸化形式在DS患者中的表达量均高于其同龄的正常对照者。免疫荧光共聚焦结果显示,在室管膜损伤区蓄积的GFAP阳性星形细胞同时表达αB-晶状蛋白;而且在正常人和DS患者脑组织中,GFAP/PDGFRα双阳性的细胞也能表达αB-晶状蛋白。结论：由于αB-晶状蛋白的分子伴侣活性和抗凋亡活性是磷酸化依赖的,所以DS患者脑组织中αB-晶状蛋白水平的升高可能反映了DS患者脑组织中的一种细胞保护机制发生了改变,这可能是由21三体编码基因诱导或增强的应激条件造成的。
Objective： To explore the significance of the levels and distribution of total αB-crystallin and its phosphorylated forms at Ser-45 and Ser-59 in the brain tissues of Down syndrome （DS） subjects. Methods： We collected formalin-fixed and paraffin-embedded brain tissues from 5 control subjects from 5 months to 23 years of age and 11 DS cases from 4 months to 17 years of age, as well as frozen brain tissues from 12 control subjects from 9 months to 23 years of age and 12 DS cases from 6 months to 23 years of age. Western blot was used for detection of total oLB-crystallin and its phosphorylated forms at Ser-45 and Ser-59. Immunofluorescence confocal method was applied for positioning of αB-crystallin. Results： In the frontal cortex and white matter of DS subjects, αB-crystallin and its phosphorylated form at Ser-59 could be detected already in infants, whereas αB-crystallin phosphorylated form at Ser-45 was weakly expressed in older children. The expressions of αB-crystallin and its phosphorylated form at Ser-59 and Ser-45 were higher in the DS subjects than in the controls of the same age. Immunoreactivity to αB-crystallin showed that αB-crystallin could be found in GFAP-positive astrocytes accumulated at the sites of ependymal injury of DS subjects. Moreover, in both DS and control brains, some GFAP/platelet-derived growth factor receptor a-positive cells also expressed αB-crystallin. Conclusion： The chaperone and anti-apoptotic activities of αB-crystallin are phosphorylation- dependent. Thus, the enhanced phosphorylation of αB-crystallin in the brains of young DS subjects might reflect a cytoprotective mechanism mobilized, which might result from the stress conditions induced or augmented by the effect of genes encoded by the triplicated chromosome 21.
作者
杨迎春
夏建文
林雅君
杨惠萍
陈兴
张秋萍
YANG Ying-chun XIA Jian-wen LIN Ya-jun YANG Hui-ping CHEN Xing ZHANG Qiu-ping(The Department of Pediatrics, Yangpu District Central Hospital, Tongji University, Shanghai, 200090, China Medical College, Tongji University, Shanghai, 200092, China)
出处
《现代生物医学进展》
CAS
2016年第36期7074-7078,共5页
Progress in Modern Biomedicine
基金
上海市卫计委基金资助项目(YW2015A-36)
