Coordinated expression of heme oxygenase-1 and ubiquitin in the porcine heart subjected to ischemia and reperfusion

Abstract

Heme oxygenase (HO) isozymes, HO-1 and HO-2 catalyze the cleavage of heme b to form the antioxidant biliverdin IXa, iron and the putative cellular messenger carbon monoxide (CO). Heat and stress have been reported to induce the expression of HO-1, in analogy to ubiquitin, a protein of 8 kDa involved in ATP dependent proteolysis. Earlier, we have shown in anesthetized pigs that brief periods of coronary artery occlusion followed by reperfusion produce prolonged regional cardiac dysfunction (stunning) associated with altered expression of a number of genes. In the present study, we report on a coordinated expression pattern of HO-1 and ubiquitin in the same porcine model in which the left anterior descending coronary artery (LAD) was occluded for 10 min and reperfused for 30 min (group I) and after a second occlusion of 10 min, reperfused for either 30 min (group II) or 90 min (group III) or 210 min (group IV). Myocardial tissue from LAD (stunned) and left circumflex coronary artery (LCx, control) perfused regions were collected in liquid nitrogen and analysed by Northern and dot blot hybridization techniques. We demonstrated a basal myocardial expression of multiple mRNAs (monomer and polymers) encoding ubiquitin and a single mRNA species (1.8 kb) encoding HO-1. However, the expression of both genes was drastically enhanced in the stunned myocardium as compared to the control in groups II and III with maximum mRNAs levels in group II. These results suggest that the myocardial adaptive response to ischemia involves the coordinated induction of HO-1 and ubiquitin, which may be indicative for the existence of a pathophysiologically important defense mechanism whereby, both degradation of denatured cellular proteins and generation of biologically active products of heme metabolism are accelerated.

Heme-oxygenase-1-induced protection against hypoxia/reoxygenation is dependent on biliverdin reductase and its interaction with PI3K/Akt pathway

“…Heme oxygenase-1 plays a central role in myocardial protection from I/R injury. The enzyme is induced several fold by hypoxia and reoxygenation [28,29], and genetic mouse models of HO-1 deficiency have greater propensity towards ischemia and hyperoxia induced tissue injury [12,13]. Moreover, pre-emptive delivery of HO-1 gene markedly reduces infarct size following acute I/R [10,11], suggesting that enhanced basal level of HO-1 preconditions the myocardium [12,30] and renders it resistant to subsequent episodes of I/R injury [14].…”

Hypoxia induces severe right ventricular dilatation and infarction in heme oxygenase-1 null mice

“…Under pathophysiological conditions, however, HO-1, but not HO-2, is induced in the heart and blood vessels (13)(14)(15)(16)(17). For example, we and others have reported that bacterial endotoxin markedly increases HO-1 expression in VSMCs and cardiomyocytes in vivo (15,17,18).…”

Molecular cloning, sequence analysis and pharmacological properties of the porcine 5‐HT1D receptor

“…The frozen tissue was transferred to guanidium thiocyanate bu er, homogenized (Ultra-Turrax homogenizer, model T8, Janke & Kunkel GmbH, Staufen, Germany) and the total RNA was extracted as described earlier (Chomczynski & Sacchi, 1987;Sharma et al, 1996). The RNA concentration was measured by UV absorbance at 260 nm using a Gene Quant RNA/DNA calculator (Pharmacia-LKB, Biochrom, UK) and the quality of RNA was assessed by OD 260 /OD 280 ratio of 41.8 as well as by formaldehyde-agarose gel electrophoresis.…”