Function of L-Type Calcium Channel Microdomain in Human Myocytes from Hearts with Ischemic versus Dilated Cardiomyopathies
Function of L-Type Calcium Channel Microdomain in Human Myocytes from Hearts with Ischemic versus Dilated Cardiomyopathies
复制标题
缺血性心肌病与扩张型心肌病患者心肌细胞中 L 型钙通道微区的功能
DOI：
10.1016/j.bpj.2017.11.3444
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发表时间：
2018
影响因子：
3.4
通讯作者：
Sanchez-Alonso J
中科院分区：
文献类型：
--
作者：
Sanchez-Alonso J
方法：分别从供体正常心脏和合并和不合并LVAD的DCM或ICM患者心脏组织中分离心肌细胞。LTCC电流被记录在不同的细胞区室：t管（TT）和它们之间的区域或“波峰”，使用超分辨率扫描膜片钳技术。di8 - anepps染色共聚焦显微镜下测定细胞大小和t小管密度。结果：来自衰竭心脏的心肌细胞出现肥厚表型，在DCM患者中比在ICM患者中更严重，这与LVAD部分逆转。此外，这些细胞具有较少的z -凹槽，较低的TT密度和显著增加的顶端微域LTCC密度。功能上，失败患者的ltcc开放概率异常高。有趣的是，这些与AP延长有关的促心律失常ltcc存在于DCM的波峰和ICM肌细胞的TT中。抑制剂分析表明，LTCC的过度磷酸化在DCM中通过钙调素依赖性激酶II发生，在ICM中通过蛋白激酶A发生。发现LVAD植入可以独立于疾病降低LTCC活性。结论：这些发现表明，ICM和DCM肌细胞都含有促心律失常的高活性ltcc，但它们的活性增加是由于两种不同的磷酸化途径针对不同的微结构域而发生的。
Methods: Cardiomyocytes were isolated from ventricular tissue of donor normal hearts and hearts of patients with DCM or ICM with and without LVAD. LTCC current was recorded in distinct cellular compartments: T-tubules (TT) and the areas between them or “crests”, using super-resolution scanning patch-clamp technique. Cell size and T-tubules density were measured with confocal microscopy under Di-8-ANEPPS staining.Results: Cardiomyocytes from failing hearts develop a hypertrophic phenotype, more severe in DCM than in ICM patients, which is partially reversed with LVAD. In addition, these cells have less Z-grooves, lower TT density and a significantly increased LTCC density in the crest microdomains. Functionally, LTCCs open probability revealed to be abnormally high in failing patients. These pro-arrhythmic LTCCs, as it has been proposed in relation with the AP prolongation, are, interestingly, in the crests of DCM and in the TT of ICM myocytes. Inhibitor analysis showed that hyperphosphorylation of LTCC occurs via calmodulin-dependent kinase II in DCM and via protein kinase A in ICM. Implantation of LVAD was found to reduce the LTCC activity independently of the disease.Conclusion: These findings suggest that both ICM and DCM myocytes contain pro-arrhythmic hyper-active LTCCs but their increased activity occurs as the result of two different phosphorylation pathways targeting different microdomains.