Laboratory of Cardiac Development and Differentiation, Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
J Biol Chem. 2011 Jan 14;286(2):1508-16. doi: 10.1074/jbc.M110.162966. Epub 2010 Nov 4.
Pressure and volume overload induce hypertrophic growth of postnatal cardiomyocytes and genetic reprogramming characterized by reactivation of a subset of fetal genes. Despite intense efforts, the nuclear effectors of cardiomyocyte hypertrophy remain incompletely defined. Endothelin-1 (ET-1) plays an important role in cardiomyocyte growth and is involved in mediating the neurohormonal effects of mechanical stress. Here, we show that the phenylephrine-induced complex-1 (PEX1), also known as zinc finger transcription factor ZFP260, is essential for cardiomyocyte response to ET-1 as evidenced in cardiomyocytes with PEX1 knockdown. We found that ET-1 enhances PEX1 transcriptional activity via a PKC-dependent pathway which phosphorylates the protein and further potentiates its synergy with GATA4. Consistent with a role for PEX1 in cardiomyocyte hypertrophy, overexpression of PEX1 is sufficient to induce cardiomyocyte hypertrophy in vitro and in vivo. Importantly, transgenic mice with inducible PEX1 expression in the adult heart develop cardiac hypertrophy with preserved heart function. Together, the results identify a novel nuclear effector of ET-1 signaling and suggest that PEX1 may be a regulator of the early stages of cardiac hypertrophy.
压力和容量超负荷会导致出生后心肌细胞的肥大生长,并伴有部分胎儿基因的重新激活,这是一种基因重编程现象。尽管人们进行了大量研究,但心肌细胞肥大的核效应因子仍未完全确定。内皮素-1(ET-1)在心肌细胞生长中起着重要作用,并参与介导机械应激的神经激素效应。在这里,我们表明,复合物 1(PEX1),也称为锌指转录因子 ZFP260,是 ET-1 诱导心肌细胞反应所必需的,这在 PEX1 敲低的心肌细胞中得到了证明。我们发现,ET-1 通过依赖蛋白激酶 C(PKC)的途径增强 PEX1 的转录活性,该途径使蛋白磷酸化,并进一步增强其与 GATA4 的协同作用。与 PEX1 在心肌细胞肥大中的作用一致,过表达 PEX1 足以在体外和体内诱导心肌细胞肥大。重要的是,在成年心脏中具有诱导性 PEX1 表达的转基因小鼠会发展出心脏肥大,但心脏功能得以保留。总之,这些结果确定了 ET-1 信号的一种新的核效应因子,并表明 PEX1 可能是心脏肥大早期阶段的调节剂。