title: Coronary effluent from a preconditioned heart activates the JAK-STAT pathway and induces cardioprotection in a donor heart.
abstract: Preconditioning (PC) protects against ischemia-reperfusion (I/R) injury via the activation of the JAK-STAT pathway. We hypothesized that the mediators responsible for PC can be transferred to naive myocardium through the coronary effluent. Langendorff-perfused hearts from male Sprague-Dawley rats were randomized to paired donor/acceptor protocols with or without PC in the presence or absence of the JAK-2 inhibitor AG-490 (n = 6 for each group). Warmed, oxygenated coronary effluent collected during the reperfusion phases of PC (3 cycles of 5 min ischemia and 5 min reperfusion) was administered to acceptor hearts. The hearts were then subjected to 30 min ischemia and 40 min reperfusion. The left ventricles were analyzed for phosphorylated (p)STAT-1, pSTAT-3, Bax, Bcl, Bcl-X(L)/Bcl-2-associated protein (BAD), and caspase-3 expression by Western blot. A separate group of hearts (n = 6) was analyzed for STAT activation immediately after the transfer of the PC effluent (no I-R). Baseline cardiodynamics were not different among the groups. End-reperfusion maximal change in pressure over time (+dP/dt(max)) was significantly (P < 0.05) improved in acceptor PC (3,637 +/- 199 mmHg/s) and donor PC (4,304 +/- 347 mmHg/s) hearts over non-PC donor (2,020 +/- 363 mmHg/s) and acceptor (2,624 +/- 345 mmHg/s) hearts. Similar differences were seen for minimal change in pressure over time (-dP/dt(min)). STAT-3 activation was significantly increased in donor and acceptor PC hearts compared with non-PC hearts. Conversely, pSTAT-1 and Bax expression was decreased in donor and acceptor PC hearts compared with non-PC hearts. No differences in Bcl, BAD, or caspase-3 expression were observed. Treatment with AG-490 attenuated the recovery of +/-dP/dt in acceptor PC hearts and significantly reduced pSTAT-3 expression. The PC coronary effluent activates JAK-STAT signaling, limits apoptosis, and protects myocardial performance from I/R injury.
authors.affiliation: Department of Surgery, Division of Trauma/Critical Care, Institute of Molecular Pharmacology and Biophysics, University of Cincinnati, 231 Albert B. Sabin Way, Cincinnati, OH 45267-0828, USA.
authors.forename: Lynn C
authors.initials: LC
authors.lastname: Huffman
authors.forename: Sheryl E
authors.initials: SE
authors.lastname: Koch
authors.forename: Karyn L
authors.initials: KL
authors.lastname: Butler
mesh_terms: D000818:Animals; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D004789:Enzyme Activation; D066298:In Vitro Techniques; D019157:Ischemic Preconditioning, Myocardial; D053612:Janus Kinases / Q000378:metabolism*; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D010477:Perfusion; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D050791:STAT Transcription Factors / Q000378:metabolism*; D050794:STAT1 Transcription Factor / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D020032:Tyrphostins / Q000494:pharmacology; D017725:Ventricular Pressure; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D051025:bcl-Associated Death Protein / Q000378:metabolism; D051020:bcl-X Protein / Q000378:metabolism
chemical_list: C494821:Bad protein, rat; C494828:Bax protein, rat; C494813:Bcl2l1 protein, rat; D047428:Protein Kinase Inhibitors; D050791:STAT Transcription Factors; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; C494081:Stat1 protein, rat; C494088:Stat3 protein, rat; D020032:Tyrphostins; C095512:alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein; D053612:Janus Kinases; C505410:Casp3 protein, rat; D053148:Caspase 3