Abstract：
BACKGROUND: In humans, ACTN2 mutations are identified as highly relevant to a range of cardiomyopathies such as DCM and HCM, while their association with sudden cardiac death has been observed in forensic cases. Although ACTN2 has been shown to regulate sarcomere Z-disc organization, a causal relationship between ACTN2 dysregulation and cardiomyopathies under chronic stress has not yet been investigated.
OBJECTIVE: In this work, we explored the relationship between Actn2 dysregulation and cardiomyopathies under dexamethasone treatment.
METHODS: Previous cases of ACTN2 mutations were collected and the conservative analysis was carried out by MEGA 11, the possible impact on the stability and function of ACTN2 affected by these mutations was predicted by Polyphen-2. ACTN2 was suppressed by siRNA in H9c2 cells under dexamethasone treatment to mimic the chronic stress in vitro. Then the cardiac hypertrophic molecular biomarkers were elevated, and the potential pathways were explored by transcriptome analysis.
RESULTS: Actn2 suppression impaired calcium uptake and increased hypertrophy in H9c2 cells under dexamethasone treatment. Concomitantly, hypertrophic molecular biomarkers were also elevated in Actn2-suppressed cells. Further transcriptome analysis and Western blotting data suggested that Actn2 suppression led to the excessive activation of the MAPK pathway and ERK cascade. In vitro pharmaceutical intervention with ERK inhibitors could partially reverse the morphological changes and inhibit the excessive cardiac hypertrophic molecular biomarkers in H9c2 cells.
CONCLUSIONS: Our study revealed a functional role of ACTN2 under chronic stress, loss of ACTN2 function accelerated H9c2 hypertrophy through ERK signaling. A commercial drug, Ibudilast, was identified to reverse cell hypertrophy in vitro.
OBJECTIVE: In this work, we explored the relationship between Actn2 dysregulation and cardiomyopathies under dexamethasone treatment.
METHODS: Previous cases of ACTN2 mutations were collected and the conservative analysis was carried out by MEGA 11, the possible impact on the stability and function of ACTN2 affected by these mutations was predicted by Polyphen-2. ACTN2 was suppressed by siRNA in H9c2 cells under dexamethasone treatment to mimic the chronic stress in vitro. Then the cardiac hypertrophic molecular biomarkers were elevated, and the potential pathways were explored by transcriptome analysis.
RESULTS: Actn2 suppression impaired calcium uptake and increased hypertrophy in H9c2 cells under dexamethasone treatment. Concomitantly, hypertrophic molecular biomarkers were also elevated in Actn2-suppressed cells. Further transcriptome analysis and Western blotting data suggested that Actn2 suppression led to the excessive activation of the MAPK pathway and ERK cascade. In vitro pharmaceutical intervention with ERK inhibitors could partially reverse the morphological changes and inhibit the excessive cardiac hypertrophic molecular biomarkers in H9c2 cells.
CONCLUSIONS: Our study revealed a functional role of ACTN2 under chronic stress, loss of ACTN2 function accelerated H9c2 hypertrophy through ERK signaling. A commercial drug, Ibudilast, was identified to reverse cell hypertrophy in vitro.
摘要：
背景：在人类中，ACTN2突变被鉴定为与一系列心肌病如DCM和HCM高度相关,而在法医案件中观察到它们与心脏猝死的关联。尽管ACTN2已被证明可以调节肌节Z-盘的组织，ACTN2失调与慢性应激下心肌病之间的因果关系尚未得到研究.
目的：在这项工作中，我们探讨了地塞米松治疗下Actn2失调与心肌病的关系.
方法：收集以前的ACTN2突变病例，通过MEGA11进行保守分析，Polyphen-2预测这些突变对ACTN2稳定性和功能的可能影响。在地塞米松处理下,在H9c2细胞中通过siRNA抑制ACTN2以模拟体外慢性应激。然后心脏肥大的分子生物标志物升高，并通过转录组分析探索了潜在的途径。
结果：在地塞米松治疗下，Actn2抑制会损害H9c2细胞的钙摄取并增加肥大。同时，在Actn2抑制的细胞中,肥大的分子生物标志物也升高.进一步的转录组分析和Western印迹数据表明，Actn2抑制导致MAPK途径和ERK级联的过度激活。ERK抑制剂的体外药物干预可以部分逆转H9c2细胞的形态学变化，抑制过度的心肌肥大分子生物标志物。
结论：我们的研究揭示了ACTN2在慢性应激下的功能作用，ACTN2功能的丧失通过ERK信号促进H9c2肥大。一种商业药物，Ibudilast,被鉴定为在体外逆转细胞肥大。
目的：在这项工作中，我们探讨了地塞米松治疗下Actn2失调与心肌病的关系.
方法：收集以前的ACTN2突变病例，通过MEGA11进行保守分析，Polyphen-2预测这些突变对ACTN2稳定性和功能的可能影响。在地塞米松处理下,在H9c2细胞中通过siRNA抑制ACTN2以模拟体外慢性应激。然后心脏肥大的分子生物标志物升高，并通过转录组分析探索了潜在的途径。
结果：在地塞米松治疗下，Actn2抑制会损害H9c2细胞的钙摄取并增加肥大。同时，在Actn2抑制的细胞中,肥大的分子生物标志物也升高.进一步的转录组分析和Western印迹数据表明，Actn2抑制导致MAPK途径和ERK级联的过度激活。ERK抑制剂的体外药物干预可以部分逆转H9c2细胞的形态学变化，抑制过度的心肌肥大分子生物标志物。
结论：我们的研究揭示了ACTN2在慢性应激下的功能作用，ACTN2功能的丧失通过ERK信号促进H9c2肥大。一种商业药物，Ibudilast,被鉴定为在体外逆转细胞肥大。
