Research Unit of Biomedicine, Department of Pharmacology and Toxicology, University of Oulu, P. O. BOX 5000, 90014, Oulu, Finland.
University of Florida Health Cancer Center, Gainesville, FL, 32610, USA.
Basic Res Cardiol. 2019 Jan 11;114(2):7. doi: 10.1007/s00395-018-0713-y.
Sprouty1 (Spry1) is a negative modulator of receptor tyrosine kinase signaling, but its role in cardiomyocyte survival has not been elucidated. The aim of this study was to investigate the potential role of cardiomyocyte Spry1 in cardiac ischemia-reperfusion (I/R) injury. Infarct areas of mouse hearts showed an increase in Spry1 protein expression, which localized to cardiomyocytes. To investigate if cardiomyocyte Spry1 regulates I/R injury, 8-week-old inducible cardiomyocyte Spry1 knockout (Spry1 cKO) mice and control mice were subjected to cardiac I/R injury. Spry1 cKO mice showed reduction in release of cardiac troponin I and reduced infarct size after I/R injury compared to control mice. Similar to Spry1 knockdown in cardiomyocytes in vivo, RNAi-mediated Spry1 silencing in isolated cardiomyocytes improved cardiomyocyte survival following simulated ischemia injury. Mechanistically, Spry1 knockdown induced cardiomyocyte extracellular signal-regulated kinase (ERK) phosphorylation in healthy hearts and isolated cardiomyocytes, and enhanced ERK phosphorylation after I/R injury. Spry1-deficient cardiomyocytes showed better preserved mitochondrial membrane potential following ischemic injury and an increase in levels of phosphorylated ERK and phosphorylated glycogen synthase kinase-3β (GSK-3β) in mitochondria of hypoxic cardiomyocytes. Overexpression of constitutively active GSK-3β abrogated the protective effect of Spry1 knockdown. Moreover, pharmacological inhibition of GSK-3β protected wild-type cardiomyocytes from cell death, but did not further protect Spry1-silenced cardiomyocytes from hypoxia-induced injury. Cardiomyocyte Spry1 knockdown promotes ERK phosphorylation and offers protection from I/R injury. Our findings indicate that Spry1 is an important regulator of cardiomyocyte viability during ischemia-reperfusion injury.
Sprouty1（Spry1）是一种受体酪氨酸激酶信号的负调节剂，但它在心肌细胞存活中的作用尚未阐明。本研究旨在探讨心肌细胞 Spry1 在心肌缺血再灌注（I/R）损伤中的潜在作用。小鼠心脏的梗死区显示 Spry1 蛋白表达增加，该蛋白定位于心肌细胞。为了研究心肌细胞 Spry1 是否调节 I/R 损伤，将 8 周龄的诱导型心肌细胞 Spry1 敲除（Spry1 cKO）小鼠和对照小鼠进行了心脏 I/R 损伤。与对照小鼠相比，Spry1 cKO 小鼠在 I/R 损伤后心肌肌钙蛋白 I 的释放减少，梗死面积减小。与体内 Spry1 在心肌细胞中的敲低相似，在分离的心肌细胞中，Spry1 的 RNAi 沉默可改善模拟缺血损伤后的心肌细胞存活。在机制上，Spry1 敲低在健康心脏和分离的心肌细胞中诱导细胞外信号调节激酶（ERK）磷酸化，并在 I/R 损伤后增强 ERK 磷酸化。与野生型细胞相比，Spry1 缺失的心肌细胞在缺血损伤后保留了更好的线粒体膜电位，并且缺氧心肌细胞中线粒体中磷酸化 ERK 和磷酸化糖原合成酶激酶-3β（GSK-3β）的水平增加。组成型激活的 GSK-3β 的过表达消除了 Spry1 敲低的保护作用。此外，GSK-3β 的药理学抑制可保护野生型心肌细胞免于细胞死亡，但不能进一步保护缺氧诱导损伤的 Spry1 沉默的心肌细胞免于死亡。心肌细胞 Spry1 敲低可促进 ERK 磷酸化，并为 I/R 损伤提供保护。我们的研究结果表明，Spry1 是缺血再灌注损伤期间心肌细胞存活的重要调节剂。
