Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We recently demonstrated that ischemic preconditioning (IPC) induced by cyclic episodes of short durations of ischemia and reperfusion potentiates a signal transduction cascade involving protein tyrosine kinases and MAP kinases. A rapid activation of janus kinase (JAK) and several signal transducers and activators of the transcription (STATs) including STAT3, STAT5A and STAT6 has been shown to occur during myocardial ischemia and reperfusion. This study sought to examine if JAK/STAT signaling pathway play any role in classical early phase of IPC. Isolated working rat hearts were perfused for 15 min with KHB buffer in the absence or presence of a JAK kinase inhibitor tyrphostin AG490 (5 microm) followed by IPC, 30 min global ischemia and 2 h of reperfusion. The results demonstrated extensive phosphorylation of JAK2 and STAT3 in the IPC hearts which was almost completely abolished by an inhibitor of JAK2, AG490. IPC displayed cardioprotection as evidenced by improved post-ischemic contractile recovery, decreased myocardial infarct size and reduced number of apoptotic cardiomyocytes. AG490 blocked IPC-mediated cardioprotection by altering the IPC-mediated survival signal into death signal. Thus, IPC-induced upregulation of antiapoptotic gene bcl-2 and downregulation of pro-apoptotic gene bax are decreased and increased, respectively, in the AG490 treated hearts. The results suggest that early phase of IPC potentiates JAK/STAT signaling by activating STAT3 which transmits a survival signal to the myocardium.
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PMID:Role of STAT3 in ischemic preconditioning. 1170 38

We recently demonstrated that ischemic preconditioning (PC) induced by cyclic episodes of short duration of ischemia and reperfusion potentiates a signal transduction cascade involving Janus kinase (JAK) 2 and signal transducer and activator of transcription 3 (STAT3). A rapid activation of JAK and several STATs, including STAT3, STAT5A, and STAT6 also occurred during myocardial ischemia and reperfusion. This study sought to examine whether STAT5A and STAT6 were also involved in PC. Two different animal models were used: isolated perfused working rat hearts and STAT5A and STAT6 knockout mouse hearts. The results of our study indicated phosphorylation of STAT 5A and STAT6 in the preconditioned myocardium. Tyrphostin AG490, a JAK2 inhibitor, or 4-amino-5-(4-methylphenyl)-7-(t-butyl)-pyrazolo-3,4-d-pyrimidine (PPI), a Src kinase blocker, blocked STAT5A phosphorylation, whereas STAT6 phosphorylation was blocked only with tyrphostin. As expected, significant cardioprotection was achieved in the preconditioned heart as evidenced by reduced myocardial infarct size and decreased number of apoptotic cardiomyocytes. PC-mediated cardioprotection was partially abolished when hearts were pretreated with tyrphostin, PPI, or LY-294002, a phosphatidylinositol (PI)-3 kinase inhibitor. Studies with STAT5A and STAT6 knockout mouse hearts revealed that STAT6 knockout mouse hearts, and not STAT5A knockout mouse hearts, were resistant to myocardial ischemia-reperfusion injury. The hearts from STAT5A knockout mice could not be preconditioned, whereas those from STAT6 knockout mice were easily preconditioned. The results of the present study demonstrate that STAT5A, and not STAT6, plays a role in ischemic PC. For the first time, the results also indicated a role of Src kinase pathway in STAT5A PC and PI-3 kinase-Akt pathways appear to be the downstream regulator for STAT5A-STAT6 signaling pathway.
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PMID:STAT signaling in ischemic heart: a role of STAT5A in ischemic preconditioning. 1286 May 60