A microtubule-connexin-43 regulatory link suppresses arrhythmias and cardiac fibrosis in Duchenne muscular dystrophy mice.
A microtubule-connexin-43 regulatory link suppresses arrhythmias and cardiac fibrosis in Duchenne muscular dystrophy mice.
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微管连接蛋白 43 调节环节可抑制杜氏肌营养不良小鼠的心律失常和心脏纤维化。
DOI：
10.1152/ajpheart.00179.2022
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Fraidenraich,Diego
中科院分区：
文献类型：
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作者：
Himelman,Eric;Nouet,Julie;Lillo,MauricioA;Chong,Alexander;Zhou,Delong;Wehrens,XanderHT;Rodney,GeorgeG;Xie,Lai-Hua;Shirokova,Natalia;Contreras,JorgeE;Fraidenraich,Diego
扩张型心肌病是杜氏肌营养不良症（DMD）的主要死亡原因，这是一种由缺乏肌营养不良蛋白引起的心脏和骨骼肌的遗传性退行性疾病。我们发现DMD心肌病的一个标志是心脏间隙连接通道蛋白连接蛋白43 （Cx43）的失调。Cx43羧基末端残基S325/S328/S330 （pS-Cx43）的翻译后磷酸化调节了Cx43在心脏插层盘（ID）上的正确定位和功能。同时，Cx43沿着微管（mt）输送到ID。在DMD心脏中，肌营养不良蛋白的缺乏导致MT细胞骨架高密度化和无序化，但与pS-Cx43的联系仍未得到解决。为了深入了解MTs与pS-Cx43之间的关系，我们用MT聚合抑制剂秋水仙碱（Colch）治疗DMD小鼠（mdx）和pS-Cx43缺陷小鼠（mdxS3A）。Colch治疗保护mdx而非mdxS3A小鼠免受Cx43重塑，改善MT的方向性，并增强pS-Cx43/微管蛋白的相互作用。同样，异丙肾上腺素应激的mdx小鼠可以预防严重心律失常，而mdxS3A小鼠则不能。此外，在模拟ps - cx43的mdx （mdxS3E）中，MT的方向性得到了改善。与Mdxutr+/ - S3E相比，Mdxutr+/ -和Mdxutr+/ - S3A小鼠缺乏一份与肌营养不良蛋白同源的滋养蛋白拷贝，表现出心脏纤维化增强和寿命缩短；Colch治疗可纠正mdxutr+/ -患者的心脏纤维化，但对mdxutr+/ - S3A患者无效。综上所述，这些数据表明MT方向性的改善减少了Cx43的重塑，pS-Cx43是调节MT组织的必要和充分条件，在纠正DMD小鼠心功能障碍中起着至关重要的作用。因此，鉴定作用于pS-Cx43-MT的新的组织机制将有助于开发新的DMD心肌病的心脏保护疗法。我们发现秋水仙碱对Cx43-磷缺乏的营养不良小鼠不能保护Cx43重塑。相反，Cx43-phospho-mimic营养不良小鼠表现出规范化的MT网络。我们设想了一种双向调节，即纠正营养不良的MTs导致纠正Cx43重塑，进而导致进一步纠正MTs。我们的研究结果表明，磷酸化Cx43和MTs之间存在联系，为DMD心肌病的新疗法提供了坚实的基础。
Dilated cardiomyopathy is the leading cause of death in Duchenne muscular dystrophy (DMD), an inherited degenerative disease of the cardiac and skeletal muscle caused by absence of the protein dystrophin. We showed one hallmark of DMD cardiomyopathy is the dysregulation of cardiac gap junction channel protein connexin-43 (Cx43). Proper Cx43 localization and function at the cardiac intercalated disc (ID) is regulated by post-translational phosphorylation of Cx43-carboxy-terminus residues S325/S328/S330 (pS-Cx43). Concurrently, Cx43 traffics along microtubules (MTs) for targeted delivery to the ID. In DMD hearts, absence of dystrophin results in a hyperdensified and disorganized MT cytoskeleton, yet the link with pS-Cx43 remains unaddressed. To gain insight into the relationship between MTs and pS-Cx43, DMD mice (mdx) and pS-Cx43-deficient (mdxS3A) mice were treated with an inhibitor of MT polymerization, colchicine (Colch). Colch treatment protected mdx, not mdxS3A mice, against Cx43 remodeling, improved MT directionality, and enhanced pS-Cx43/tubulin interaction. Likewise, severe arrhythmias were prevented in isoproterenol-stressed mdx, not mdxS3A mice. Furthermore, MT directionality was improved in pS-Cx43-mimicking mdx (mdxS3E). Mdxutr+/−and mdxutr+/−S3A mice, lacking one copy of dystrophin homolog utrophin, displayed enhanced cardiac fibrosis and reduced lifespan compared with mdxutr+/−S3E; and Colch treatment corrected cardiac fibrosis in mdxutr+/−but not mdxutr+/−S3A. Collectively, the data suggest that improved MT directionality reduces Cx43 remodeling and that pS-Cx43 is necessary and sufficient to regulate MT organization, which plays crucial role in correcting cardiac dysfunction in DMD mice. Thus, identification of novel organizational mechanisms acting on pS-Cx43-MT will help develop novel cardioprotective therapies for DMD cardiomyopathy.NEW & NOTEWORTHYWe found that colchicine administration to Cx43-phospho-deficient dystrophic mice fails to protect against Cx43 remodeling. Conversely, Cx43-phospho-mimic dystrophic mice display a normalized MT network. We envision a bidirectional regulation whereby correction of the dystrophic MTs leads to correction of Cx43 remodeling, which in turn leads to further correction of the MTs. Our findings suggest a link between phospho-Cx43 and MTs that provides strong foundations for novel therapeutics in DMD cardiomyopathy.