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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 detect the expression and distribution of αB-crystallin and its Ser59 and Ser45 phosphorylated forms in brain tissue of patients with Down Syndrome (DS) and to investigate the effect of αB-crystallin phosphorylation on the brain of Down’s syndrome The significance of injury. Methods: 11 cases of DS patients aged from 4 months to 17 years old and 5 normal volunteers from 5 months to 23 years old were collected for brain tissue paraffin, and 12 normal controls from 9 months to 23 years old were frozen brain The brain tissues of 12 patients aged from 6 months to 23 years old with DS were frozen and the expression of αB-crystallin, Ser59 and Ser45 phosphorylated forms in the prefrontal cortex and white matter were detected by Western blot. Immunofluorescence confocal double staining and triple staining were used to detect the localization of αB-crystallin in brain tissue. Results: αB-crystallin and its Ser59 phosphorylated form can be detected in infants and young children with DS. However, the Ser45 phosphorylated form can only be detected in adolescence, and its expression level is low. The expression level of αB-crystallin and its two phosphorylated forms in DS patients were higher than their normal controls. Immunofluorescence confocal results showed that GFAP-positive astrocytes accumulated in the ependymal lesion area expressed αB-crystallin simultaneously. In both normal and DS patients, GFAP / PDGFRα double positive cells also expressed αB - Crystalline protein. CONCLUSIONS: As the chaperone activity and anti-apoptotic activity of αB-crystallin are phosphorylation-dependent, elevated levels of αB-crystallin in brain tissue of DS patients may reflect a single cell in brain tissue of patients with DS The protective mechanism has changed, probably due to the stress conditions induced or enhanced by the trisomy 21 gene.