The ectodomain of the Notch3 receptor accumulates within the cerebrovasculature of CADASIL patients
The ectodomain of the Notch3 receptor accumulates within the cerebrovasculature of CADASIL patients
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DOI：
10.1172/jci8047
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发表时间：
2000-03-01
影响因子：
15.9
通讯作者：
Tournier-Lasserve, E
中科院分区：
文献类型：
--
作者：
Joutel, A;Andreux, F;Tournier-Lasserve, E
Notch 3的突变导致CADASIL（大脑常染色体显性成人发作性动脉病），导致人类中风和痴呆。CADASIL动脉病的特征是血管平滑肌细胞的重大改变和特异性颗粒状嗜锇性沉积物的存在。患者携带高度定型的突变，导致Notch 3受体胞外结构域的EGF样重复序列内的半胱氨酸残基为奇数。此类突变可能会改变该受体的加工或运输，或者可能有利于其寡聚化。在这项研究中，我们检查了正常组织中Notch 3的表达模式，并研究了突变对转染细胞和CADASIL大脑中Notch 3表达的影响。在正常组织中，Notch 3表达仅限于血管平滑肌细胞。Notch 3经历蛋白水解切割，导致210-kDa的细胞外片段和97-kDa的细胞内片段。在CADASIL大脑中，我们发现了210-kDa Notch 3切割产物戏剧性和选择性积累的证据。Notch 3聚集在血管平滑肌细胞的细胞质膜上，靠近但不在颗粒状嗜锇物质内。这些结果强烈表明CADASIL突变特异性地损害Notch 3胞外域而不是胞质结构域从细胞表面的清除。
Mutations in Notch3 cause CADASIL (cerebral autosomal dominant adult onset arteriopathy), which leads to stroke and dementia in humans. CADASIL arteriopathy is characterized by major alterations of vascular smooth muscle cells and the presence of specific granular osmiophilic deposits. Patients carry highly stereotyped mutations that lead to an odd number of cysteine residues within EGF-like repeats of the Notch3 receptor extracellular domain. Such mutations may alter the processing or the trafficking of this receptor, or may favor its oligomerization. In this study, we examined the Notch3 expression pattern in normal tissues and investigated the consequences of mutations on Notch3 expression in transfected cells and CADASIL brains. In normal tissues, Notch3 expression is restricted to vascular smooth muscle cells. Notch3 undergoes a proteolytic cleavage leading to a 210-kDa extracellular fragment and a 97-kDa intracellular fragment. In CADASIL brains, we found evidence of a dramatic and selective accumulation of the 210-kDa Notch3 cleavage product. Notch3 accumulates at the cytoplasmic membrane of vascular smooth muscle cells, in close vicinity to but not within the granular osmiophilic material. These results strongly suggest that CADASIL mutations specifically impair the clearance of the Notch3 ectodomain, but not the cytosolic domain, from the cell surface.