Genetic and ultrastructural studies in dilated cardiomyopathy patients: a large deletion in the lamin A/C gene is associated with cardiomyocyte nuclear envelope disruption
Genetic and ultrastructural studies in dilated cardiomyopathy patients: a large deletion in the lamin A/C gene is associated with cardiomyocyte nuclear envelope disruption
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DOI：
10.1007/s00395-010-0085-4
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发表时间：
2010-05-01
影响因子：
9.5
通讯作者：
Tesson, Frederique
中科院分区：
文献类型：
--
作者：
Gupta, Pallavi;Bilinska, Zofia T.;Tesson, Frederique
在扩张型心肌病（DCM）患者的心肌细胞中，主要的核膜异常，如破坏和/或核内细胞器的存在，很少被描述。在这项研究中，我们筛选了一系列25个不相关的DCM患者样本(a)心肌细胞核异常和(b) LMNA和TMPO突变，因为它们是两个导致DCM的基因，编码参与维持核膜结构的蛋白质。在研究的25个心脏样本中，我们在8例患者中发现了主要的心肌细胞核异常。直接测序可以在3例患者中检测到3个杂合LMNA突变（p.D192G, p.Q353K和p.R541S）。通过多重连接依赖探针扩增(MLPA)/实时定量PCR，我们在一名患者中发现了包含LMNA基因外显子3-12的杂合缺失。免疫染色表明，这种缺失导致该患者心肌细胞中纤层蛋白a /C表达减少。在心肌细胞核膜主要异常的患者中发现了这种LMNA缺失和p.D192G突变，而在没有特异性核膜异常的患者中发现了p.Q353K和p.R541S突变。研究中没有DCM患者携带TMPO基因突变。综上所述，我们没有发现在DCM的发病和严重程度、核异常的存在以及LMNA突变的存在或不存在之间存在基因型-表型关系的证据。我们证明了LMNA的大量缺失与核包膜蛋白水平降低相关，这表明单倍功能不全机制可能导致心肌细胞核包膜破坏，从而成为DCM发病机制的基础。
Major nuclear envelope abnormalities, such as disruption and/or presence of intranuclear organelles, have rarely been described in cardiomyocytes from dilated cardiomyopathy (DCM) patients. In this study, we screened a series of 25 unrelated DCM patient samples for (a) cardiomyocyte nuclear abnormalities and (b) mutations in LMNA and TMPO as they are two DCM-causing genes that encode proteins involved in maintaining nuclear envelope architecture. Among the 25 heart samples investigated, we identified major cardiomyocyte nuclear abnormalities in 8 patients. Direct sequencing allowed the detection of three heterozygous LMNA mutations (p.D192G, p.Q353K and p.R541S) in three patients. By multiplex ligation-dependant probe amplification (MLPA)/quantitative real-time PCR, we found a heterozygous deletion encompassing exons 3-12 of the LMNA gene in one patient. Immunostaining demonstrated that this deletion led to a decrease in lamin A/C expression in cardiomyocytes from this patient. This LMNA deletion as well as the p.D192G mutation was found in patients displaying major cardiomyocyte nuclear envelope abnormalities, while the p.Q353K and p.R541S mutations were found in patients without specific nuclear envelope abnormalities. None of the DCM patients included in the study carried a mutation in the TMPO gene. Taken together, we found no evidence of a genotype-phenotype relationship between the onset and the severity of DCM, the presence of nuclear abnormalities and the presence or absence of LMNA mutations. We demonstrated that a large deletion in LMNA associated with reduced levels of the protein in the nuclear envelope suggesting a haploinsufficiency mechanism can lead to cardiomyocyte nuclear envelope disruption and thus underlie the pathogenesis of DCM.