Pathological protein generation in cerebral small vessel disease

摘要 脑部小血管疾病(SVD)是导致痴呆的重要原因 到阿尔茨海默氏症和帕金森氏症等神经退行性疾病。 常染色体显性遗传性脑动脉病伴皮质下梗塞和 脑白质病变(CADASIL)是SVD最常见的遗传性病因。临床 CADASIL的特征包括痴呆症、反复中风和精神障碍。 了解CADASIL的病理可能导致治疗SVD的策略。 CADASIL是由NOTCH3的半胱氨酸改变突变引起的，这表明氧化还原 该蛋白的改变可能导致SVD。NOTCH3的改变形式可能导致 大量蛋白质堆积、细胞分离和平滑肌细胞死亡 CADASIL。特定的细胞丢失、蛋白质构象改变和蛋白质 CADASIL中的积聚提示与退行性疾病有相似之处，如 阿尔茨海默氏症和帕金森氏症。在初步研究中，我们发现了一种新的帖子- 翻译生成的NOTCH3片段，称为NTF(NOTCH3 N-末端 片段)从人CADASIL组织中提取。我们证明了NTF能够反式- 用多个还原半胱氨酸将NOTCH3还原为NOTCH3的病理形式 (MRC-N3)。此外，NTF可引起小鼠大脑的急性和慢性变化。 正常情况下不容易患上SVD。NTF的酶促释放发生在细胞中， 我们发现了一种潜在的在CADASIL组织中增加的蛋白酶。在目标1中，我们 将确定促进NOTCH3蛋白还原为MRC-N3的NTF的特征。在……里面 目的2，我们将探讨NTF介导的蛋白质减少的程度。在AIM中 3，我们将确定一种富含CADASIL的脑蛋白酶是否参与 NTF一代。这些实验探索了一种新的、自我永生的分子 在人脑中产生病理性蛋白质的机制。 该项目产生的信息可能会改进目前SVD的翻译模型 并使治疗靶点的发现取得进展。

ABSTRACT Cerebral small vessel disease (SVD) is an important cause of dementia and contributes to neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common inherited cause of SVD. Clinical features of CADASIL include dementia, recurrent stroke, and psychiatric disorders. Understanding the pathology of CADASIL may lead to strategies to treat SVD. CADASIL is caused by cysteine-altering mutations in NOTCH3, suggesting that redox alteration of this protein could contribute to SVD. Altered forms of NOTCH3 may lead to massive protein accumulation, cell separation, and smooth muscle cell death seen in CADASIL. Specific cell loss, protein conformational alterations, and protein accumulation seen in CADASIL suggest similarities to degenerative disorders such as Alzheimer's and Parkinson's diseases. In preliminary studies, we identify a novel post- translationally generated fragment of NOTCH3, called NTF (NOTCH3 N-terminal fragment) from human CADASIL tissues. We show that NTF is capable of trans- reducing NOTCH3 into a pathological form of NOTCH3 with multiple reduced cysteines (mrc-N3). Moreover, NTF causes both acute and chronic changes in the brains of mice which are not normally susceptible to SVD. Enzymatic liberation of NTF occurs in cells, and we identify a potential protease that is increased in CADASIL tissues. In Aim 1, we will define the features of NTF that promote NOTCH3 protein reduction to mrc-N3. In Aim 2, we will we explore the extent of protein reduction mediated by NTF. And in Aim 3, we will determine whether a brain protease that is enriched in CADASIL participates in NTF generation. These experiments explore a novel, self-perpetuating molecular mechanism by which pathological proteins are produced in the human brain. Information generated by this project could improve current translational models of SVD and enable progress in the discovery of therapeutic targets.