Activation of JAK/STAT pathway transduces cytoprotective signal in rat acute myocardial infarction

• Published in: Cardiovascular research 2000-09, Vol.47 (4), p.797-805
• Main Authors: NEGORO, Shinji, KUNISADA, Keita, TONE, Eiroh, FUNAMOTO, Masanobu, OH, Hidemasa, KISHIMOTO, Tadamitsu, YAMAUCHI-TAKIHARA, Keiko
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Animals; Apoptosis; bcl-2-Associated X Protein; Biological and medical sciences; Blotting, Western; Cardiology. Vascular system; Caspase 3; Caspases - metabolism; Cells, Cultured; Coronary heart disease; DNA-Binding Proteins - metabolism; Enzyme Activation; Enzyme Inhibitors - pharmacology; Heart; In Situ Nick-End Labeling; Janus Kinase 1; Janus Kinase 2; Male; Medical sciences; Mitogen-Activated Protein Kinases - metabolism; Myocardial Infarction - metabolism; Myocardium - metabolism; Phosphatidylinositol 3-Kinases - metabolism; Phosphorylation; Precipitin Tests; Protein-Tyrosine Kinases - antagonists & inhibitors; Protein-Tyrosine Kinases - metabolism; Proto-Oncogene Proteins - metabolism; Proto-Oncogene Proteins c-bcl-2; Random Allocation; Rats; Rats, Sprague-Dawley; Rats, Wistar; Signal Transduction - drug effects; Signal Transduction - physiology; STAT1 Transcription Factor; STAT3 Transcription Factor; Trans-Activators - metabolism; Tyrphostins - pharmacology
• ISSN: 0008-6363; 1755-3245
• DOI: 10.1016/s0008-6363(00)00138-3

We reported that the activation of gp130 transduced hypertrophic and cytoprotective signals via Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway in cardiac myocytes. Recent in vivo experiments have demonstrated that the JAK/STAT pathway is activated in acute pressure overload hearts. The present study was designed to examine whether the JAK/STAT pathway is also activated in acute myocardial infarction (AMI) and to determine its pathophysiological roles in ischemic heart disease. AMI model was generated by the ligation of proximal left anterior descending coronary artery of male Wistar rat. They were sacrificed at various time points ranging from 1 to 24 h after coronary ligation and their hearts were examined. Tyrosine phosphorylation of STAT3 was observed in the myocardium obtained from both the ischemic area and the healthy border area adjacent to the infarcted area. The AMI rats were next randomly assigned to two groups, one with coronary ligation only (group M), and the other with coronary ligation with AG-490 treatment (1 mg/kg i.v., every 4 h), a specific JAK2 inhibitor (group A). In group A, phosphorylation of STAT3 was significantly suppressed and caspase-3 activity and Bax expression were significantly increased in the myocardium after AMI. In group M, few apoptotic myocytes were identified in the border area by means of TUNEL assay. However, a significant increase in apoptotic cells was observed in group A. Administration of JAK2 inhibitor resulted in deterioration of myocardial viability in AMI hearts. The JAK/STAT pathway is activated in AMI myocardium and plays a pivotal role in cytoprotective signaling.