TMEM16A Plays an Insignificant Role in Myocardium Remodeling but May Promote Angiogenesis of Heart During Pressure-overload.
TMEM16A Plays an Insignificant Role in Myocardium Remodeling but May Promote Angiogenesis of Heart During Pressure-overload.
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DOI：
10.3389/fphys.2022.897619
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发表时间：
2022
影响因子：
4
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背景：心脏肥大（CH）随着心肌质量的增加而发生，作为对压力增加的适应性补偿。长期 CH 会导致失代偿性心力衰竭 (HF)。在肥大的心脏中观察到血管内皮生长因子（VEGF）增强的血管生成；在衰竭的心脏中观察到血管紧张素 II (AngII) 导致的血管生成受损。血管生成是由血管内皮细胞（EC）执行的。 Ca2+ 稳态异常是心脏肥大和衰竭的标志性特征。 Ca2+ 激活的氯离子通道跨膜蛋白 16A (TMEM16A) 在心肌细胞和 EC 中表达，但其在应激状态下心脏中的作用仍不清楚。 方法：建立压力过载诱导的CH和HF小鼠模型。进行超声心动图评估心脏参数。使用定量实时 PCR、传统和简单的蛋白质印迹分析来量化分子表达。采用全细胞膜片钳实验检测心肌细胞的TMEM16A电流（ITMEM16A）和动作电位持续时间（APD）。 VEGF 和 AngII 分别用于 EC 培养，以分别模拟增强或受损的血管生成。通过siRNA或慢病毒转染获得TMEM16A低表达和过表达的EC。进行伤口愈合、管形成和 EC 球体发芽测定以评估迁移和血管生成。 结果：在CH和HF的发展过程中，TMEM16A分子表达水平和全细胞ITMEM16A密度均没有显着变化。 ITMEM16A 包含瞬时外向电流，但不能解释肥大或衰竭心肌细胞中的 APD 延长。在培养的EC中，TMEM16A敲低抑制迁移和血管生成，TMEM16A过表达则显示相反的结果。 VEGF 对迁移和血管生成的促进作用在 TMEM16A 低表达的 EC 中减少，但在 TMEM16A 过表达的 EC 中增加。 AngII 对迁移和血管生成的抑制在 TMEM16A 低表达的 EC 中增强，但在 TMEM16A 过表达的 EC 中减弱。 结论：TMEM16A 在压力超负荷期间对心肌重塑的作用不显着。 TMEM16A 在正常条件或模拟应激下是迁移和血管生成的正调节因子。 TMEM16A 可能成为缺血性心脏病等缺血性疾病中血管生成上调的新靶点。
Background: Cardiac hypertrophy (CH) occurs with an increase in myocardium mass as an adaptive compensation to increased stress. Prolonged CH causes decompensated heart failure (HF). Enhanced angiogenesis by vascular endothelial growth factor (VEGF) is observed in hypertrophied hearts; impaired angiogenesis by angiotensin II (AngII) is observed in failing hearts. Angiogenesis is executed by vascular endothelial cells (ECs). Abnormal Ca2+ homeostasis is a hallmark feature of hypertrophied and failing hearts. Ca2+-activated chloride channel transmembrane protein 16A (TMEM16A) is expressed in cardiomyocytes and ECs but its role in heart under stress remains unknown. Methods: Pressure-overload-induced CH and HF mouse models were established. Echocardiography was performed to evaluate cardiac parameters. Quantitative real-time PCR, traditional and simple western assays were used to quantify molecular expression. Whole-cell patch-clamp experiments were used to detect TMEM16A current (ITMEM16A) and action potential duration (APD) of cardiomyocytes. VEGF and AngII were used separately in ECs culture to simulate enhanced or impaired angiogenesis, respectively. TMEM16A low-expressed and over-expressed ECs were obtained by siRNA or lentivirus transfection. Wound healing, tube formation and ECs spheroids sprouting assays were performed to assess migration and angiogenesis. Results: Neither TMEM16A molecular expression levels nor whole-cell ITMEM16A density varied significantly during the development of CH and HF. ITMEM16A comprises transient outward current, but doesn’t account for APD prolongation in hypertrophied or failing cardiomyocytes. In cultured ECs, TMEM16A knockdown inhibited migration and angiogenesis, TMEM16A overexpression showed opposite result. Promotion of migration and angiogenesis by VEGF was decreased in TMEM16A low-expressed ECs but was increased in TMEM16A over-expressed ECs. Inhibition of migration and angiogenesis by AngII was enhanced in TMEM16A low-expressed ECs but was attenuated in TMEM16A over-expressed ECs. Conclusion: TMEM16A contributes insignificantly in myocardium remodeling during pressure-overload. TMEM16A is a positive regulator of migration and angiogenesis under normal condition or simulated stress. TMEM16A may become a new target for upregulation of angiogenesis in ischemic disorders like ischemic heart disease.