连接蛋白 43 构象改变由 LMNA 基因突变Glu82Lys 引起的家族性扩张型心肌病伴房室传导阻滞。

Connexin 43 remodeling induced by LMNA gene mutation Glu82Lys in familial dilated cardiomyopathy with atrial ventricular block.

机构信息

Cardiovascular Institute and Fu Wai Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.

出版信息

Chin Med J (Engl). 2010 Apr 20;123(8):1058-62.

PMID:20497714

Abstract

BACKGROUND

Mutations in the lamin A/C gene (LMNA) may cause familial dilated cardiomyopathy (dilated cardiomyopathy) characterized by early onset atrio-ventricular block (A-V block) before the manifestation of dilated cardiomyopathy and high risk of sudden death due to ventricular arrhythmia, which is very similar to the phenotype of gap junction related heart disease. This study aimed to determine the expression and localization of connexins in neonatal myocytes transfected with wild-type (WT) or mutant LMNA to elucidate how these mutations cause heart diseases.

METHODS

We studied the connexin 43 (Cx43) and connexin 40 (Cx40) expression in cultured neonatal myocytes transfected with wild-type (WT) or mutant LMNA (Glu82Lys (E82K) and Arg644Cys (R644C)) using confocal imaging and Western blotting analysis.

RESULTS

Cx43 protein expression was reduced by 40% in cells transfected with LMNA E82K than that in cells transfected with WT LMNA cDNA. Confocal imaging showed that the Cx43 located inside the cells by LMNA E82K. By contrast, LMNA E82K mutation had no effect on expression and localization of Cx40. LMNA R644C transfection did not show any significant effects on gap junctions at all.

CONCLUSIONS

Our findings suggest that LMNA E82K significantly reduced the Cx43 expression and altered its localization which may be one of the pathological mechanisms underlying LMNA-related heart disease.

摘要

背景

核纤层蛋白 A/C 基因突变（LMNA）可能导致家族性扩张型心肌病（扩张型心肌病），其特征为在扩张型心肌病出现之前出现早期房室传导阻滞（A-V 阻滞），且由于室性心律失常导致猝死的风险较高，这与缝隙连接相关心脏病的表型非常相似。本研究旨在确定转染野生型（WT）或突变型 LMNA 的新生心肌细胞中连接蛋白的表达和定位，以阐明这些突变如何导致心脏病。

方法

我们使用共聚焦成像和 Western blot 分析研究了转染野生型（WT）或突变型 LMNA（Glu82Lys（E82K）和 Arg644Cys（R644C））的培养新生心肌细胞中连接蛋白 43（Cx43）和连接蛋白 40（Cx40）的表达。

结果

与转染 WT LMNA cDNA 的细胞相比，转染 LMNA E82K 的细胞中 Cx43 蛋白表达减少了 40%。共聚焦成像显示，Cx43 由 LMNA E82K 定位在细胞内部。相比之下，LMNA E82K 突变对 Cx40 的表达和定位没有影响。LMNA R644C 转染对缝隙连接没有任何显著影响。