Loss-of-Function of MYO5B is the Main Cause of Microvillus Inclusion Disease: 15 Novel Mutations and a CaCo-2 RNAi Cell Model
Loss-of-Function of MYO5B is the Main Cause of Microvillus Inclusion Disease: 15 Novel Mutations and a CaCo-2 RNAi Cell Model
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DOI：
10.1002/humu.21224
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发表时间：
2010-05-01
期刊：
影响因子：
3.9
通讯作者：
Huber, Lukas A.
中科院分区：
文献类型：
--
作者：
Ruemmele, Frank M.;Mueller, Thomas;Huber, Lukas A.
常染色体隐性遗传性微绒毛包涵体病（MVID）的特征是在出生后的最初几周内开始出现顽固性腹泻。MVID的标志是绒毛肠细胞表面缺乏微绒毛，出现内衬微绒毛的细胞内空泡（微绒毛内含物），以及肠细胞中高碘酸-希夫（PAS）阳性囊泡的细胞质积聚。最近，我们在第一组9名MVID患者中鉴定了MYO 5 B突变，MYO 5 B编码非常规Vb型肌球蛋白马达蛋白。在这项研究中，我们在11名无关的MVID患者中发现了MYO 5 B的15个新的无义和错义突变。应用荧光显微镜、Western blotting和电子显微镜分析MYO 5 B siRNA敲低对极化的、具有刷状缘的CaCo-2细胞的影响。失去表面微绒毛，微绒毛夹杂物的形成增加，PAS阳性内膜室的近顶端富集诱导极化，过滤器生长的CaCo-2细胞，MYO 5 B敲低。我们的数据表明，MYO 5 B突变是微绒毛包涵体疾病的主要原因，MYO 5 B敲低在体外重演了大多数细胞表型，因此独立地显示MYO 5 B功能丧失是微绒毛包涵体疾病的原因。Mutat 31：544-551，2010年。(C)2010 Wiley-Liss，Inc.
Autosomal recessive microvillus inclusion disease (MVID) is characterized by an intractable diarrhea starting within the first few weeks of life. The hallmarks of MVID are a lack of microvilli on the surface of villous enterocytes, occurrence of intracellular vacuoles lined by microvilli (microvillus inclusions), and the cytoplasmic accumulation of periodic acid-Schiff (PAS)-positive vesicles in enterocytes. Recently, we identified mutations in MYO5B, encoding the unconventional type Vb myosin motor protein, in a first cohort of nine MVID patients. In this study, we identified 15 novel nonsense and missense mutations in MYO5B in 11 unrelated MVID patients. Fluorescence microscopy, Western blotting, and electron microscopy were applied to analyze the effects of MYO5B siRNA knockdown in polarized, brush border possessing CaCo-2 cells. Loss of surface microvilli, increased formation of microvillus inclusions, and subapical enrichment of PAS-positive endomembrane compartments were induced in polarized, filter-grown CaCo-2 cells, following MYO5B knock-down. Our data indicate that MYO5B mutations are a major cause of microvillus inclusion disease and that MYO5B knockdown recapitulates most of the cellular phenotype in vitro, thus independently showing loss of MYO5B function as the cause of microvillus inclusion disease. Hum Mutat 31:544-551, 2010. (C) 2010 Wiley-Liss, Inc.