Mutant connexin 32 abnormally distributed in the vascular endothelial cells of X-linked Charcot-Marie-Tooth disease type 1 patients
10.3760/cma.j.issn.1006-7876.2011.10.012
- VernacularTitle:突变缝隙连接蛋白32在X连锁Charcot-Marie-Tooth病1型患者的外周血管内皮细胞异常表达
- Author:
Xinghua LUAN
;
Daojun HONG
;
Xiaohui QIAO
;
He Lü
;
Zhaoxia WANG
;
Yun YUAN
- Publication Type:Journal Article
- Keywords:
Charcot-Marie-Tooth disease;
Connexins;
Blood vessels;
Endothelial cells
- From:
Chinese Journal of Neurology
2011;44(10):689-693
- CountryChina
- Language:Chinese
-
Abstract:
ObjectiveTo investigate expression distribution of mutant connexin 32 (Cx32) protein in human endothelial cells in patients with X-linked Charcot-Marie-Tooth disease type 1 ( CMTX1 ) .MethodsNerve biopsies were performed in 3 patients with CMTX1 and in 3 non-CMTX1 controls. Cx32 mutations of c. 379A ＞ T( I127F), c. 533A ＞ G(D178G) and c. 590C ＞ T(A197V) were identified in these 3 patients respectively.Immunofluorescent (IMF) staining of nerve blood vessel was processed with antibodies against Cx32, Yon Willebrand factor and Cx40. The mutant Cx32 was constructed in pEGFP-N plasmid (pEGFP-N1-Cx32) and was transfected in HeLa cells. Cx32 and GRP78, a marker of endoplasmic reticulum ( ER), were stained by IMF in HeLa cells to investigate expression of mutant Cx32. ResultsIn 3 control cases, Cx32 was visualized by IMF staining as dots along gap junction of vascular endothelial cells,and it was coexisted with Cx40.However, immunoreactivity of Cx32 in 3 patients was predominantly decreased and was not located in endothelial gap junction. The transfection of 3 Cx32 mutants into HeLa cells demonstrated thepathogenic changes.The cells withthemutationc. 379A ＞T found Cx32 accumulations in the cytoplasm; the cells with mutation c. 533A ＞G showed few staining positive dots surrounding the nuclear and the cells with c. 590C ＞ T showed dot-like expression of Cx32 both in the cytoplasmicand cell membrane. The mutant Cx32 was not overlapped with expression of the marker of ER.ConclusionsMutant Cx32 might cause dysfunction of endothelial gap-junctions due to the abnormal expression of Cx32 in level and location in the vascular endothelial cells of CMTX1 patients.
