自噬相关蛋白在皮质发育畸形病变中的表达  

Expression of autophagy-related proteins in malformations of cortical development

作　　者：陈诗赟 

机构地区：[1]首都医科大学宣武医院病理科,北京100053

出　　处：《中华病理学杂志》2015年第5期305-309,共5页Chinese Journal of Pathology

基　　金：北京市卫生系统高层次卫生技术人才培养计划项目(2011-3-095)

摘　　要：目的检测自噬相关蛋白Beclin-1、LC3及p62在难治性癫痫相关皮质发育畸形病变中的表达情况，初步探讨皮质发育畸形出现细胞水平异常的可能机制。方法选用18例手术切除的致痫灶标本，包括结节硬化综合征(TSC)、局灶性皮质发育不良(FCD)11b型及FCDI型各6例。采用免疫组织化学染色(EnVison二步法)对3种蛋白分别在3组病变中细胞水平的表达情况进行定性分析，并计数Beclin-1、LC3染色阳性细胞数进行比较；应用Westernblot方法对LC3蛋白在3组病变中的表达进行定量比较分析。结果免疫组织化学染色结果显示3种蛋白均主要表达于FCDIIb型及TSC组中的形态异常神经元和气球样细胞／巨大细胞内。Beclin-1为胞质内颗粒状或弥漫阳性，另可见到轴索强阳性表达；LC3为胞质内弥漫阳性或核周阳性；p62为胞质内弥漫阳性，部分为核及核周阳性。此外，形态异常神经元中Beclin-1、LC3及p62阳性程度高于气球样细胞／巨大细胞。而作为对照的FCDI组中仅有个别或部分细胞呈弱阳性表达。Beclin-1和LC3染色中阳性细胞数均为TSC组>FCDIIb组>FCDI组，且TSC组、FCDIIb组与FCDI组的差异均具有统计学意义(P<0．05)。Westernblot结果显示LC3蛋白在病灶组织内的表达量为TSC组<FCD11b组<FCDI组。结论TSC、FCDIIb中的形态异常神经元和气球样细胞／巨大细胞中存在自噬抑制，推测自噬的异常可能与蛋白质的异常堆积密切相关；但形态异常神经元和气球样细胞中自噬异常具体机制不完全一致。Objective To study the expression of autophagy-related proteins (Beclin-1, LC3 and p62) in brain tissue with malformations of cortical development and related molecular pathogenesis. Methods The brain tissue of 18 cases with epileptogenic foci resection, including 6 cases of tuberous sclerosis complex (TSC) , 6 cases of focal cortical dysplasia type H b ( FCD H b) and 6 cases of focal cortical dysplasia type I (FCD I ) , were retrieved. Immunohistochemical study for Beclin-1, LC3 and p62 proteins was performed. The degree of positivity for Beelin-1 and LC3 proteins was compared. Western blot was used to quantitatively analyze the LC3 protein in focal lesion of each disease groups. Results Immunohistochemical study showed that the three proteins were mainly expressed in the dysmorphic neurons and balloon cells/giant cells of TSC and FCD I1 b. The positivity was more intense in the dysmorphic neurons than the other cell types. Immunostaining for Beelin-1 showed granular or diffuse cytoplasmic positivity, in addition to the strong expression in axons. On the other hand, LC3 showed diffuse or perinuclear cytoplasmic expression. The staining for p62 was mainly cytoplasmic or perinuclear and sometimes nuclear. In FCD type I , only individual cells showed positive expression for the three proteins. The number of Beclin-1 and LC3-positive cells was larger in TSC group, followed by FCDIIb group and FCDI group. And there were significant differences between TSC group and FCDI group, as well as FCDIIb group and FCD ! group (P < 0.05). Quantitative expression of LC3 protein by Western blot showed smaller amount in TSC group, followed by FCD II b group and FCD I group. Conclusions The dysmorphic neurons and balloon cells/giant cells of TSC and FCD II b show abnormality in autophagy, resulting in intracytoplasmic protein accumulation. There are differences in molecular pathogenesis in these cell types.

关 键 词：皮质发育畸形 自噬 癫痫 

分 类 号：R742[医药卫生—神经病学与精神病学]