The molecular phenotype of human cardiac myosin associated with hypertrophic obstructive cardiomyopathy.
The molecular phenotype of human cardiac myosin associated with hypertrophic obstructive cardiomyopathy.
复制标题
人类心脏肌球蛋白的分子表型与肥厚的阻塞性心肌病有关。
DOI：
10.1093/cvr/cvn094
复制
发表时间：
2008-08-01
影响因子：
10.8
通讯作者：
Marston SB
中科院分区：
文献类型：
--
作者：
Jacques AM;Briceno N;Messer AE;Gallon CE;Jalilzadeh S;Garcia E;Kikonda-Kanda G;Goddard J;Harding SE;Watkins H;Esteban MT;Tsang VT;McKenna WJ;Marston SB
本研究的目的是比较心肌运动蛋白，肌球蛋白，并在肥厚型心肌病患者的心脏肌肉切除术与心脏衰竭和非衰竭供体心肌的功能和结构特性的分离肌细胞收缩性。分离肌球蛋白，并使用体外运动试验进行研究。肌球蛋白轻链-1亚型的分布通过双向电泳测定。肌球蛋白轻链-2磷酸化通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳使用Pro-Q Diamond磷蛋白染色来测量。在肌切除术肌球蛋白驱动下，肌动蛋白丝的运动分数比供体肌球蛋白少21%（P = 0.006），而滑动速度没有差异（在6个配对实验中，肌切除术肌球蛋白为0.310 ± 0.034 µm/s，供体肌球蛋白为0.305 ± 0.019 µm/s）。衰竭的心脏肌球蛋白显示出18%的运动性降低。一个肌切除术肌球蛋白样品产生了一致的更高的滑动速度比供体心脏肌球蛋白，并确定了致病的重链突变（V606 M）。在肌球蛋白切除术中，心房轻链-1相对于心室轻链-1的水平为20 ± 5%，而供体心脏肌球蛋白为11 ± 5%，肌球蛋白轻链-2磷酸化水平降低了30- 45%。与供体心肌细胞相比，分离的心肌细胞显示收缩幅度降低（1.61 ± 0.25 vs. 3.58 ± 0.40%）和舒张速率降低（TT 50%= 0.32 ± 0.09 vs. 0.17 ± 0.02 s）。肌切除术样本的收缩性类似于在终末期衰竭心肌中发现的收缩功能减退表型，而与主要刺激无关，并且这种表型不是肥大诱导突变的直接影响。肌球蛋白重链突变引起肥厚型心肌病的存在可以从一个简单的功能测定预测。
The aim of the study was to compare the functional and structural properties of the motor protein, myosin, and isolated myocyte contractility in heart muscle excised from hypertrophic cardiomyopathy patients by surgical myectomy with explanted failing heart and non-failing donor heart muscle. Myosin was isolated and studied using an in vitro motility assay. The distribution of myosin light chain-1 isoforms was measured by two-dimensional electrophoresis. Myosin light chain-2 phosphorylation was measured by sodium dodecyl sulphate–polyacrylamide gel electrophoresis using Pro-Q Diamond phosphoprotein stain. The fraction of actin filaments moving when powered by myectomy myosin was 21% less than with donor myosin (P = 0.006), whereas the sliding speed was not different (0.310 ± 0.034 for myectomy myosin vs. 0.305 ± 0.019 µm/s for donor myosin in six paired experiments). Failing heart myosin showed 18% reduced motility. One myectomy myosin sample produced a consistently higher sliding speed than donor heart myosin and was identified with a disease-causing heavy chain mutation (V606M). In myectomy myosin, the level of atrial light chain-1 relative to ventricular light chain-1 was 20 ± 5% compared with 11 ± 5% in donor heart myosin and the level of myosin light chain-2 phosphorylation was decreased by 30–45%. Isolated cardiomyocytes showed reduced contraction amplitude (1.61 ± 0.25 vs. 3.58 ± 0.40%) and reduced relaxation rates compared with donor myocytes (TT50% = 0.32 ± 0.09 vs. 0.17 ± 0.02 s). Contractility in myectomy samples resembles the hypocontractile phenotype found in end-stage failing heart muscle irrespective of the primary stimulus, and this phenotype is not a direct effect of the hypertrophy-inducing mutation. The presence of a myosin heavy chain mutation causing hypertrophic cardiomyopathy can be predicted from a simple functional assay.