【作者】 杨玉芳； 王茉； 杨平； 王自山； 黄莉； 宿靓； 王卫； 余梅； 黄芳；

【Author】 Yang,Y.;

【机构】 复旦大学医学神经生物学国家重点实验室,脑科学研究院； 上海中医药大学基础医学院中医经方平台； 上海市南方模式生物有限公司； 同济大学生命科学学院； 浙江省同德医院；

【摘要】 阿尔滋海默病的重要病理特征之一是脑内β-淀粉样蛋白聚集形成的老年斑,也被认为是引起神经元功能异常的原因。之前的研究发现,在啮齿动物和非人的灵长目动物脑内注射富含Aβ沉积的脑匀浆液能够引起大脑内Aβ的聚集,从而引起神经元损伤并产生临床的病理表现,类似朊蛋白(prion)的病理机制。朊蛋白病已有数例因食用被朊蛋白污染的食物而引起的病例。我们给野生型小鼠和APP/PS1小鼠都饲喂富含Aβ的脑匀浆液,并通过免疫组织化学,蛋白免疫印迹和行为学实验,调查脑内Aβ是否可能通过口服途径进行传播。我们也给AD线虫中喂食了脑匀浆液后诱导线虫瘫痪,并观察了AD线虫的瘫痪曲线,检测了线虫体内的Aβ。我们对线虫进行了RNA测序后针对一些异常基因使用抑制剂进行感染,再次诱导了线虫瘫痪并观察抑制剂效果。我们在线虫实验中发现,AD线虫在饲喂脑匀浆液后,由线虫体壁细胞内Aβ3～42的沉积诱导的瘫痪得到了显著的改善,这可能是由于脑匀浆液中一种对温度敏感的成分引起的。我们对CL4176线虫进行了转录组测序,发现,脑匀浆液可能通过多条通路对线虫的瘫痪产生改善效果,比如泛素蛋白降解系统和TGF-β信号通路。我们使用了该两条通路的靶向抑制剂对线虫进行干扰,发现这两条通路的抑制剂都部分的抑制了脑匀浆对AD线虫瘫痪的改善作用。尽管如此,我们在野生型小鼠和APP/PS1小鼠中都饲喂了普通脑匀浆液和富含Aβ的脑匀浆液,但是无论从Aβ沉积,胶质细胞激活,或是行为学表现上都没有发现野生型小鼠和APP/PS1小鼠有任何不同的表现。我们的结果表明,Aβ不具有像朊蛋白一样通过口服就能在脑内进行传播的病理机制。但是,脑匀浆液强烈地改善了AD转基因线虫的AD病理样表现,可能是通过泛素蛋白降解系统和TGF-β通路实现的,这提示靶向多条信号通路的"鸡尾酒"疗法可能成为治疗AD的有效方案。更多还原

【Abstract】 The deposition of β-sheet rich amyloid in senile plaques is a pathological hallmark of Alzheimer’s disease(AD), which is thought to cause neuronal dysfunction. Previous studies have strongly implicated that intracerebral infusion of brain extract containing aggregated β-amyloid(Aβ) is able to induce cerebral amyloidosis thus causing neuronal damage and clinical abnormalities in rodents and nonhuman primates, which are reminiscent of a prion-like mechanism. Prion disease has been documented in cases of prion-contaminated food consumption.We investigated whether cerebral transmission of Aβ was possible via oral administration of Aβ-rich brain extract in non-susceptible and susceptible host mice by immunohistochemistry, western blotting, and behavior tests. Also brain extracts were supplied to AD transgenic Caenorhabditis elegans, and paralysis curve were conducted, following detection of Aβ amyloid. RNA sequencing of nematodes was applied then inhibitors for relevant dysregulated genes were used in the paralysis induction.A significant improvement of AD pathology was detected in worms fed with Aβ-rich or normal brain extracts, which was attributable to the heat-sensitive components of brain extracts. Transcriptome sequencing of CL4176 nematodes suggested that brain extracts could delay worm paralysis through multiple pathways, including ubiquitin mediated proteolysis and TGF-β signaling pathway. Inhibitors of the ubiquitin proteasome system and the TGF-β signaling pathway partially blocked the suppressive effects of brain extracts on worm paralysis.However, the oral treatment of AD brain extract or normal brain extract neither aggravated nor mitigated the Aβ load, glial activation or the abnormal behaviors in recipient APP/PS1 mice.Our results suggest that systemic transmissible mechanisms of prion proteopathy may not apply to β amyloid, at least in terms oforal administration. However, brain extracts strongly ameliorated AD pathology in AD transgenic nematodes partially through the ubiquitin proteasome system and the TGF-β pathway, which indicated that cocktail drugs targeting multiple signaling pathways might have potential application in AD therapy.更多还原