Molecular Defects in Cardiac Myofilament Ca(2+)-Regulation Due to Cardiomyopathy-Linked Mutations Can Be Reversed by Small Molecules Binding to Troponin.
Molecular Defects in Cardiac Myofilament Ca(2+)-Regulation Due to Cardiomyopathy-Linked Mutations Can Be Reversed by Small Molecules Binding to Troponin.
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DOI：
10.3389/fphys.2018.00243
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发表时间：
2018
影响因子：
4
通讯作者：
Marston SB
中科院分区：
文献类型：
--
作者：
Sheehan A;Messer AE;Papadaki M;Choudhry A;Kren V;Biedermann D;Blagg B;Khandelwal A;Marston SB
遗传性心肌病，肥厚型心肌病（HCM）和扩张型心肌病（DCM）是相对常见的，可能危及生命，目前无法治疗。突变通常发生在心肌收缩蛋白中，并通过肌钙蛋白引起异常的Ca 2+调节。HCM通常与更高的肌丝Ca 2+敏感性有关，而在HCM和DCM突变组织中，PKA引起的肌钙蛋白I（TnI）磷酸化与肌丝Ca 2+敏感性的调节之间的关系通常是解偶联的，这对于对肾上腺素的正常反应至关重要。肾上腺素能反应减弱，这可能使心脏在压力下容易衰竭。目前还没有可以预防或治疗肌节心肌病的化合物或干预措施。需要在更基本的水平上起作用以影响疾病过程的新疗法。我们证明，表没食子儿茶素-3没食子酸酯（EGCG）被发现能够恢复之间的耦合关系的Ca 2+敏感性和TnI磷酸化的突变体细丝正常在体外，独立的突变（15突变测试）。我们将这种特性称为“再耦合”。EGCG在体外逆转由肌病突变引起的异常的作用似乎是治疗遗传性HCM和DCM的理想药物特性，但已知EGCG在体内是混杂的，因此不适合作为治疗药物。因此，我们研究了其他结构相关的化合物是否可以在没有这些脱靶效应的情况下重新偶联肌丝。我们使用定量体外运动试验筛选40个化合物，相关的C-末端Hsp 90抑制剂，并发现23个可以重新耦合突变肌丝。再偶联剂和Hsp 90抑制剂之间没有相关性。由于TnI磷酸化引起的Ca 2+敏感性偏移恢复到2.2 ± 0.01倍（n = 19），而野生型细纤维中为2.0 ± 0.24倍（n = 7）。这些化合物中有许多是纯的再偶联剂或纯的脱敏剂，表明这些性质是独立的;此外，再偶联能力可能随着化合物结构的微小变化而丧失，表明特异性的可能性。可以重新偶联的小分子可能具有治疗潜力。- 遗传性心肌病是目前在基础水平上无法治疗的常见疾病，因此非常需要找到小分子治疗方法。- 我们已经确定了一个分子水平的功能障碍常见于几乎所有的突变：解偶联的肌钙蛋白I磷酸化和肌丝Ca 2+敏感性的调制，肾上腺素的正常反应必不可少的关系。- 我们已经确定了一类新的药物，能够降低钙敏感性和/或恢复肌钙蛋白I磷酸化和钙敏感性之间的关系。- 重新耦合现象可以解释的基础上，一个单一的机制是可测试的。- 用各种不同结构的小分子进行测量可以指示重耦合所需的关键分子特征，并允许预测其他潜在的重耦合剂。亮点
The inherited cardiomyopathies, hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) are relatively common, potentially life-threatening and currently untreatable. Mutations are often in the contractile proteins of cardiac muscle and cause abnormal Ca2+ regulation via troponin. HCM is usually linked to higher myofilament Ca2+-sensitivity whilst in both HCM and DCM mutant tissue there is often an uncoupling of the relationship between troponin I (TnI) phosphorylation by PKA and modulation of myofilament Ca2+-sensitivity, essential for normal responses to adrenaline. The adrenergic response is blunted, and this may predispose the heart to failure under stress. At present there are no compounds or interventions that can prevent or treat sarcomere cardiomyopathies. There is a need for novel therapies that act at a more fundamental level to affect the disease process. We demonstrated that epigallocatechin-3 gallate (EGCG) was found to be capable of restoring the coupled relationship between Ca2+-sensitivity and TnI phosphorylation in mutant thin filaments to normal in vitro, independent of the mutation (15 mutations tested). We have labeled this property “re-coupling.” The action of EGCG in vitro to reverse the abnormality caused by myopathic mutations would appear to be an ideal pharmaceutical profile for treatment of inherited HCM and DCM but EGCG is known to be promiscuous in vivo and is thus unsuitable as a therapeutic drug. We therefore investigated whether other structurally related compounds can re-couple myofilaments without these off-target effects. We used the quantitative in vitro motility assay to screen 40 compounds, related to C-terminal Hsp90 inhibitors, and found 23 that can re-couple mutant myofilaments. There is no correlation between re-couplers and Hsp90 inhibitors. The Ca2+-sensitivity shift due to TnI phosphorylation was restored to 2.2 ± 0.01-fold (n = 19) compared to 2.0 ± 0.24-fold (n = 7) in wild-type thin filaments. Many of these compounds were either pure re-couplers or pure desensitizers, indicating these properties are independent; moreover, re-coupling ability could be lost with small changes of compound structure, indicating the possibility of specificity. Small molecules that can re-couple may have therapeutic potential. - Inherited cardiomyopathies are common diseases that are currently untreatable at a fundamental level and therefore finding a small molecule treatment is highly desirable. - We have identified a molecular level dysfunction common to nearly all mutations: uncoupling of the relationship between troponin I phosphorylation and modulation of myofilament Ca2+-sensitivity, essential for normal responses to adrenaline. - We have identified a new class of drugs that are capable of both reducing Ca2+-sensitivity and/or recouping the relationship between troponin I phosphorylation and Ca2+-sensitivity. - The re-coupling phenomenon can be explained on the basis of a single mechanism that is testable. - Measurements with a wide range of small molecules of varying structures can indicate the critical molecular features required for recoupling and allows the prediction of other potential re-couplers. HIGHLIGHTS
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影响因子：
4
作者：
Ingolfsson, Helgi I.;Thakur, Pratima;Herold, Karl F.;Hobart, E. Ashley;Ramsey, Nicole B.;Periole, Xavier;de Jong, Djurre H.;Zwama, Martijn;Yilmaz, Duygu;Hall, Katherine;Maretzky, Thorsten;Hemmings, Hugh C., Jr.;Blobel, Carl;Marrink, Siewert J.;Kocer, Armagan;Sack, Jon T.;Andersen, Olaf S.
通讯作者：
Andersen, Olaf S.
影响因子：
4.2
作者：
Hall JA;Forsberg LK;Blagg BS
通讯作者：
Blagg BS
影响因子：
2.7
作者：
Marston, SB;Fraser, IDC;Roper, G
通讯作者：
Roper, G
影响因子：
3.6
作者：
Feng, Wei;Hwang, Hyun Seok;Knollmann, Bjoern C.
通讯作者：
Knollmann, Bjoern C.
影响因子：
4.8
作者：
Dvornikov, Alexey V.;Smolin, Nikolai;de Tombe, Pieter P.
通讯作者：
de Tombe, Pieter P.