Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University (Y.F., Y.L., B.C., Z.W., T.W., Q.W., L.W.), Nanjing Medical University, China.
State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology (Y.C., H.Z., Y.G., J.S., X.G.), Nanjing Medical University, China.
Circulation. 2020 May 12;141(19):1554-1569. doi: 10.1161/CIRCULATIONAHA.119.040747. Epub 2020 Feb 26.
In mammals, regenerative therapy after myocardial infarction is hampered by the limited regenerative capacity of adult heart, whereas a transient regenerative capacity is maintained in the neonatal heart. Systemic phosphorylation signaling analysis on ischemic neonatal myocardium might be helpful to identify key pathways involved in heart regeneration. Our aim was to define the kinase-substrate network in ischemic neonatal myocardium and to identify key pathways involved in heart regeneration after ischemic insult.
Quantitative phosphoproteomics profiling was performed on infarct border zone of neonatal myocardium, and kinase-substrate network analysis revealed 11 kinases with enriched substrates and upregulated phosphorylation levels, including checkpoint kinase 1 (CHK1) kinase. The effect of CHK1 on cardiac regeneration was tested on Institute of Cancer Research CD1 neonatal and adult mice that underwent apical resection or myocardial infarction.
In vitro, CHK1 overexpression promoted whereas CHK1 knockdown blunted cardiomyocyte proliferation. In vivo, inhibition of CHK1 hindered myocardial regeneration on resection border zone in neonatal mice. In adult myocardial infarction mice, CHK1 overexpression on infarct border zone upregulated mammalian target of rapamycin C1/ribosomal protein S6 kinase b-1 pathway, promoted cardiomyocyte proliferation, and improved cardiac function. Inhibiting mammalian target of rapamycin activity by rapamycin blunted the neonatal cardiomyocyte proliferation induced by CHK1 overexpression in vitro.
Our study indicates that phosphoproteome of neonatal regenerative myocardium could help identify important signaling pathways involved in myocardial regeneration. CHK1 is found to be a key signaling responsible for neonatal regeneration. Myocardial overexpression of CHK1 could improve cardiac regeneration in adult hearts by activating the mammalian target of rapamycin C1/ribosomal protein S6 kinase b-1 pathway. Thus, CHK1 might serve as a potential novel target in myocardial repair after myocardial infarction.
在哺乳动物中，心肌梗死后的再生疗法受到成年心脏再生能力有限的阻碍，而新生心脏则保持着短暂的再生能力。对缺血性新生心肌的系统磷酸化信号分析可能有助于确定心脏再生中涉及的关键途径。我们的目的是确定缺血性新生心肌中的激酶-底物网络，并确定缺血性损伤后心脏再生中涉及的关键途径。
对新生心肌梗死边缘区进行定量磷酸化蛋白质组学分析，激酶-底物网络分析显示，包括检查点激酶 1（CHK1）激酶在内的 11 种激酶具有丰富的底物和上调的磷酸化水平。在接受心尖切除术或心肌梗死的癌症研究所 CD1 新生和成年小鼠上测试了 CHK1 对心脏再生的影响。
在体外，CHK1 的过表达促进了心肌细胞的增殖，而 CHK1 的敲低则削弱了心肌细胞的增殖。在体内，CHK1 的抑制阻碍了新生小鼠的心肌再生。在成年心肌梗死小鼠中，梗死边缘区 CHK1 的过表达上调了哺乳动物雷帕霉素靶蛋白 C1/核糖体蛋白 S6 激酶 b-1 途径，促进了心肌细胞的增殖，并改善了心脏功能。雷帕霉素抑制哺乳动物雷帕霉素靶蛋白活性削弱了 CHK1 过表达在体外诱导的新生心肌细胞增殖。
我们的研究表明，新生再生心肌的磷酸蛋白质组学可以帮助确定心脏再生中涉及的重要信号通路。CHK1 是负责新生再生的关键信号。CHK1 在心肌中的过表达可以通过激活哺乳动物雷帕霉素靶蛋白 C1/核糖体蛋白 S6 激酶 b-1 途径来改善成年心脏的心脏再生。因此，CHK1 可能成为心肌梗死后心肌修复的潜在新靶点。
