Adeno-sh-beta-catenin abolishes ischemic preconditioning-mediated cardioprotection by downregulation of its target genes VEGF, Bcl-2, and survivin in ischemic rat myocardium.
beta-Catenin, the downstream target of glycogen synthase kinase-3beta (GSK-3beta), plays a vital role in ischemic preconditioning (IP)-mediated cardioprotection. In the present study, we investigated the mechanism of IP-mediated cardioprotection through suppression of beta-catenin expression by intramyocardial injection of adeno-sh-RNA against beta-catenin (BCT) (4 x 10(8) pfu). Adeno-LacZ (LZ) was used as control. The rats were randomized into (a) LZ + ischemia-reperfusion (IR); (b) LZIPIR; (c) BCTIR; and (d) BCTIPIR. Isolated hearts from each group were subjected to 30 min of I followed by 2 h of R. Both IPIR group hearts were subjected to IP (5 min I + 10 min R; four cycles) before IR. Significant reduction in left ventricular functional recovery (78 vs. 88 mm Hg), dp/dt(max) (1,802 vs. 2,189 mm Hg/sec), and aortic flow (4 vs. 9 ml/min) was observed in BCTIPIR compared with LZIPIR at 120 min of reperfusion. Increased infarct size (42 vs. 24%) and apoptotic cardiomyocytes (122 vs. 58 counts/60 HPF) were observed in BCTIPIR compared with LZIPIR. Realtime PCR and Western blot analysis showed significant downregulation in mRNA and protein expression of VEGF, Bcl-2, and survivin in BCTIPIR compared with LZIPIR. These findings indicated for the first time that silencing beta-catenin abolished IP-mediated cardioprotection, probably through inhibition of VEGF-Bcl-2 and survivin.
Thirunavukkarasu
Mahesh
M
Molecular Cardiology and Angiogenesis Laboratory, Department of Surgery, University of Connecticut Medical Center, Farmington, Connecticut 06030-1110, USA.
Han
Zhihua
Z
Zhan
Lijun
L
Penumathsa
Suresh Varma
SV
Menon
Venugopal P
VP
Maulik
Nilanjana
N
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D015536:Down-Regulation; D005786:Gene Expression Regulation; D005822:Genetic Vectors / Q000235:genetics; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods; D008297:Male; D008869:Microtubule-Associated Proteins / Q000235:genetics* / Q000378:metabolism; D017202:Myocardial Ischemia / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000077022:Survivin; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000378:metabolism; D051176:beta Catenin / Q000235:genetics* / Q000378:metabolism
C516989:Birc5 protein, rat; D008869:Microtubule-Associated Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D000077022:Survivin; D042461:Vascular Endothelial Growth Factor A; D051176:beta Catenin