Dual Functional States of R406W-Desmin Assembly Complexes Cause Cardiomyopathy With Severe Intercalated Disc Derangement in Humans and in Knock-In Mice
Dual Functional States of R406W-Desmin Assembly Complexes Cause Cardiomyopathy With Severe Intercalated Disc Derangement in Humans and in Knock-In Mice
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DOI：
10.1161/circulationaha.120.050218
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发表时间：
2020-12-01
期刊：
影响因子：
37.8
通讯作者：
Schroeder, Rolf
中科院分区：
文献类型：
--
作者：
Herrmann, Harald;Cabet, Eva;Schroeder, Rolf
背景：人类结蛋白基因突变导致肌病和心肌病。本研究的目的是阐明的杂合子R406 W-结蛋白突变的严重和早发性cardiac phenotype.Methods的发展中启动的分子机制：我们报告了一个青少年患者谁接受心脏移植的结果，限制性心肌病引起的杂合子R406 W-结蛋白突变。用特异于406 W-结蛋白和闰盘蛋白的抗体分析心脏的切片。通过细胞转染和体外组装实验研究了R406 W突变对结蛋白分子特性的影响。为了证明真正的心脏组织上的突变的有害影响，我们进一步产生和分析R405 W-结蛋白基因敲入小鼠窝藏的orthopathic形式的人R406 W-结蛋白。结果：显微镜分析显示结蛋白聚集体和没有结蛋白丝在闰盘。桥粒斑蛋白、网蛋白、N-钙粘蛋白和连接蛋白43的异常组织结构揭示了闰盘内的结构变化。下一代测序证实DES变体c.1216C>T（p.R406W）是唯一的致病突变。细胞转染研究揭示了R406 W-结蛋白的双重行为，其整合到内源性中间丝系统和分离成蛋白质聚集体。在体外，R406 W-结蛋白形成异常粗的细丝，并组织成复杂的细丝聚集体和原纤维片。与此相反，组装的突变体和野生型结蛋白的等摩尔混合物产生嵌合细丝表面上正常的形态，但偶尔突出的不规则性。杂合和纯合R405 W-结蛋白敲入小鼠发生肌病和心肌病。特别地，来自患者的主要组织病理学结果在来自两种基因型的R405 W-结蛋白敲入小鼠的心脏中重现。此外，而杂合子敲入小鼠有一个正常的寿命，纯合子动物在3个月的年龄，因为平滑肌相关的胃肠phenotype.Conclusions死亡：我们证明，R406 W-结蛋白挑起其严重的心脏毒性潜力的一种新的病理机制，并发的双功能状态的突变结蛋白组装复合物的基础上的结蛋白丝从闰盘和它们的结构解体的解偶联。
Background:Mutations in the human desmin gene cause myopathies and cardiomyopathies. This study aimed to elucidate molecular mechanisms initiated by the heterozygous R406W-desmin mutation in the development of a severe and early-onset cardiac phenotype.Methods:We report an adolescent patient who underwent cardiac transplantation as a result of restrictive cardiomyopathy caused by a heterozygous R406W-desmin mutation. Sections of the explanted heart were analyzed with antibodies specific to 406W-desmin and to intercalated disc proteins. Effects of the R406W mutation on the molecular properties of desmin were addressed by cell transfection and in vitro assembly experiments. To prove the genuine deleterious effect of the mutation on heart tissue, we further generated and analyzed R405W-desmin knock-in mice harboring the orthologous form of the human R406W-desmin.Results:Microscopic analysis of the explanted heart revealed desmin aggregates and the absence of desmin filaments at intercalated discs. Structural changes within intercalated discs were revealed by the abnormal organization of desmoplakin, plectin, N-cadherin, and connexin-43. Next-generation sequencing confirmed the DES variant c.1216C>T (p.R406W) as the sole disease-causing mutation. Cell transfection studies disclosed a dual behavior of R406W-desmin with both its integration into the endogenous intermediate filament system and segregation into protein aggregates. In vitro, R406W-desmin formed unusually thick filaments that organized into complex filament aggregates and fibrillar sheets. In contrast, assembly of equimolar mixtures of mutant and wild-type desmin generated chimeric filaments of seemingly normal morphology but with occasional prominent irregularities. Heterozygous and homozygous R405W-desmin knock-in mice develop both a myopathy and a cardiomyopathy. In particular, the main histopathologic results from the patient are recapitulated in the hearts from R405W-desmin knock-in mice of both genotypes. Moreover, whereas heterozygous knock-in mice have a normal life span, homozygous animals die at 3 months of age because of a smooth muscle-related gastrointestinal phenotype.Conclusions:We demonstrate that R406W-desmin provokes its severe cardiotoxic potential by a novel pathomechanism, where the concurrent dual functional states of mutant desmin assembly complexes underlie the uncoupling of desmin filaments from intercalated discs and their structural disorganization.