Klotho attenuates isoproterenol-induced hypertrophic response in H9C2 cells by activating Na+/K+-ATPase and inhibiting the reverse mode of Na+/Ca2+-exchanger
Klotho attenuates isoproterenol-induced hypertrophic response in H9C2 cells by activating Na+/K+-ATPase and inhibiting the reverse mode of Na+/Ca2+-exchanger
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Klotho 通过激活 Na /K -ATP 酶并抑制 Na /Ca2 -交换器的反向模式来减弱异丙肾上腺素诱导的 H9C2 细胞肥大反应
DOI：
10.1007/s11626-017-0215-5
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发表时间：
2018-03-01
影响因子：
2.1
通讯作者：
Si, Liang-Yi
中科院分区：
文献类型：
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作者：
Tang, Gang;Shen, Yi;Si, Liang-Yi
心脏肥大在心力衰竭中起主要作用，并与患者发病率和死亡率相关。钙超载是心肌肥厚的主要危险因素，Na+/K+-ATP酶（Na+/K+-ATPase，NKA）不仅可以调节细胞内Na+水平，还可以通过Na+/Ca 2 +-交换器（Na+/Ca 2 +-exchange，NCX）调控细胞内Ca 2+（[Ca 2 +]i）水平。最近的研究报道klotho可以影响[Ca 2 +]i水平。本研究旨在探讨klotho在改善异丙肾上腺素诱导的H9 C2细胞肥大反应中的作用。将H9 C2细胞随机分为对照组和异丙肾上腺素（ISO）（10 μM）组。用Klotho蛋白（10 μg/ml）或NKAα2 siRNA检测异丙肾上腺素诱导的肥大反应的变化。荧光分光光度法测定[Ca 2 +]i的变化。结果显示，与对照组相比，异丙肾上腺素处理后24 h和48 h H9 C2细胞内[Ca 2 +]i水平升高，肥大基因表达增加。klotho蛋白处理后，对照组和ISO组NKAα1和NKAα2表达均增加，NKA活性增加，NCX活性降低。ISO组经Klotho蛋白治疗后，[Ca ~（2+）]i水平降低，肥大基因表达减少。然而，这些作用都被NKAα2 siRNA阻断。结论：klotho通过激活NKA和抑制NCX的逆转模式抑制异丙肾上腺素诱导的H9 C2细胞肥大反应，这种作用可能与上调NKAα2的表达有关。
Cardiac hypertrophy plays a major role in heart failure and is related to patient morbidity and mortality. Calcium overloading is a main risk for cardiac hypertrophy, and Na+/K+-ATPase (NKA) has been found that it could not only regulate intracellular Na+ levels but also control the intracellular Ca2+ ([Ca2+]i) level through Na+/Ca2+-exchanger (NCX). Recent studies have reported that klotho could affect [Ca2+]i level. In this study, we aimed at exploring the role of klotho in improving isoproterenol-induced hypertrophic response of H9C2 cells. The H9C2 cells were randomly divided into control and isoproterenol (ISO) (10 μM) groups. Klotho protein (10 μg/ml) or NKAα2 siRNA was used to determine the changes in isoproterenol-induced hypertrophic response. The alterations of [Ca2+]i level were measured by spectrofluorometry. Our results showed that H9C2 cells which were treated with isoproterenol presented a higher level of [Ca2+]i and hypertrophic gene expression at 24 and 48 h compared with the control group. Moreover, the expressions of NKAα1 and NKAα2 were both increased in control and ISO groups after treating with klotho protein; meanwhile, the NKA activity was increased and NCX activity was decreased after treatment. Consistently, the [Ca2+]i level and hypertrophic gene expression were decreased in ISO group after klotho protein treatment. However, these effects were both prevented by transfecting with NKAα2 siRNA. In conclusion, these findings demonstrated that klotho inhibits isoproterenol-induced hypertrophic response in H9C2 cells by activating NKA and inhibiting the reverse mode of NCX and this effect may be associated with the upregulation of NKAα2 expression.