The coordinated increased expression of biliverdin reductase and heme oxygenase-2 promotes cardiomyocyte survival: A reductase-based peptide counters β-adrenergic receptor ligand-mediated cardiac dysfunction
ABSTRACT HO-2 oxidizes heme to CO and biliverdin; the latter is reduced to bilirubin by biliverdin reductase (BVR). In addition, HO-2 is a redox-sensitive K/Ca(2)-associated protein, and BVR is an S/T/Y kinase. The two enzymes are components of cellular defense mechanisms. This is the first reporting of regulation of HO-2 by BVR and that their coordinated increase in isolated myocytes and intact heart protects against cardiotoxicity of β-adrenergic receptor activation by isoproterenol (ISO). The induction of BVR mRNA, protein, and activity and HO-2 protein was maintained for ≥ 96 h; increase in HO-1 was modest and transient. In isolated cardiomyocytes, experiments with cycloheximide, proteasome inhibitor MG-132, and siBVR suggested BVR-mediated stabilization of HO-2. In both models, activation of BVR offered protection against the ligand's stimulation of apoptosis. Two human BVR-based peptides known to inhibit and activate the reductase, KKRILHC(281) and KYCCSRK(296), respectively, were tested in the intact heart. Perfusion of the heart with the inhibitory peptide blocked ISO-mediated BVR activation and augmented apoptosis; conversely, perfusion with the activating peptide inhibited apoptosis. At the functional level, peptide-mediated inhibition of BVR was accompanied by dysfunction of the left ventricle and decrease in HO-2 protein levels. Perfusion of the organ with the activating peptide preserved the left ventricular contractile function and was accompanied by increased levels of HO-2 protein. Finding that BVR and HO-2 levels, myocyte apoptosis, and contractile function of the heart can be modulated by small human BVR-based peptides offers a promising therapeutic approach for treatment of cardiac dysfunctions.
- SourceAvailable from: Maria Elena Chanez-Cardenas
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- "Other evidences that support a protective role of HO-2 in different models are the coordinated expression of BVR and HO-2 which promotes cardiomyocyte survival in response to isoproterenol ; the HO-2 involvement in the signal transduction pathway responsible to morphine tolerance through CO production ; and the coordinated expression and protein interaction of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4 (PFKFB4) and HO-2 in glucose homeostasis in HepG2 human hepatome cells . "
ABSTRACT: Hemeoxygenase (HO) system is responsible for cellular heme degradation to biliverdin, iron, and carbon monoxide. Two isoforms have been reported to date. Homologous HO-1 and HO-2 are microsomal proteins with more than 45% residue identity, share a similar fold and catalyze the same reaction. However, important differences between isoforms also exist. HO-1 isoform has been extensively studied mainly by its ability to respond to cellular stresses such as hemin, nitric oxide donors, oxidative damage, hypoxia, hyperthermia, and heavy metals, between others. On the contrary, due to its apparently constitutive nature, HO-2 has been less studied. Nevertheless, its abundance in tissues such as testis, endothelial cells, and particularly in brain, has pointed the relevance of HO-2 function. HO-2 presents particular characteristics that made it a unique protein in the HO system. Since attractive results on HO-2 have been arisen in later years, we focused this review in the second isoform. We summarize information on gene description, protein structure, and catalytic activity of HO-2 and particular facts such as its cellular impact and activity regulation. Finally, we call attention on the role of HO-2 in oxygen sensing, discussing proposed hypothesis on heme binding motifs and redox/thiol switches that participate in oxygen sensing as well as evidences of HO-2 response to hypoxia.Oxidative medicine and cellular longevity 07/2014; 2014(10):604981. DOI:10.1155/2014/604981 · 3.36 Impact Factor
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- "Apart from its antioxidative effects, a cytoprotective action independent of heme degradation has been reported , . In fact, BLVR has been demonstrated to affect cell signaling pathways by regulating stress-responsive genes, including both HMOX1 , , and HMOX2 . Two isoforms of human BLVR, BLVRA (OMIM*109750) and BLVRB (OMIM*600941), products of different genes, have been described . "
ABSTRACT: Hepatitis C virus (HCV) infection is associated with systemic oxidative stress. Since the heme catabolic pathway plays an important role in antioxidant protection, we attempted to assess the gene expression of key enzymes of heme catabolism, heme oxygenase 1 (HMOX1), heme oxygenase 2 (HMOX2), and biliverdin reductase A (BLVRA) in the liver and peripheral blood leukocytes (PBL) of patients chronically infected with HCV. Gene expressions (HMOX1, HMOX2, BLVRA) and HCV RNA were analyzed in PBL of HCV treatment naïve patients (n = 58) and controls (n = 55), with a subset of HCV patients having data on hepatic gene expression (n = 35). Based upon the therapeutic outcome, HCV patients were classified as either responders (n = 38) or treatment-failure patients (n = 20). Blood samples in HCV patients were collected at day 0, and week 12, 24, 36, and 48 after the initiation of standard antiviral therapy. Compared to the controls, substantially increased BLVRA expression was detected in PBL (p<0.001) of therapeutically naïve HCV patients. mRNA levels of BLVRA in PBL closely correlated with those in liver tissue (r2 = 0.347,p = 0.03). A marked difference in BLVRA expression in PBL between the sustained responders and patients with treatment failure was detected at week 0 and during the follow-up (p<0.001). Multivariate analysis revealed that BLVRA basal expression in PBL was an independent predictor for sustained virological response (OR 15; 95% CI 1.05-214.2; P = 0.046). HMOX1/2 expression did not have any effect on the treatment outcome. Our results suggest that patients with chronic HCV infection significantly upregulate BLVRA expression in PBL. The lack of BLVRA overexpression is associated with non-responsiveness to standard antiviral therapy; whereas, HMOX1/2 does not seem to have any predictive potential.PLoS ONE 03/2013; 8(3):e57555. DOI:10.1371/journal.pone.0057555 · 3.23 Impact Factor
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- "Preceding work has shown that nitrosative and oxidative stress-induced modifications on hippocampal BVR isoform A are an early event in the pathogenesis of Alzheimer disease (Barone et al., 2011). The Maines group reported on protection of cardiomyocytes by synergistic BVR and HO-2 upregulation as a potential strategy against cardiac dysfunction (Ding et al., 2011). In addition to these novel observations, a common BVR isoform A polymorphism was found to be associated with essential hypertension in Kazaks (Lin et al., 2011). "
ABSTRACT: Reactive oxygen species (ROS) and signaling events are involved in the pathogenesis of endothelial dysfunction and represent a major contribution to vascular regulation. Molecular signaling is highly dependent on ROS. But depending on the amount of ROS production it might have toxic or protective effects. Despite a large number of negative outcomes in large clinical trials (e.g., HOPE, HOPE-TOO), antioxidant molecules and agents are important players to influence the critical balance between production and elimination of reactive oxygen and nitrogen species. However, chronic systemic antioxidant therapy lacks clinical efficacy, probably by interfering with important physiological redox signaling pathways. Therefore, it may be a much more promising attempt to induce intrinsic antioxidant pathways in order to increase the antioxidants not systemically but at the place of oxidative stress and complications. Among others, heme oxygenase (HO) has been shown to be important for attenuating the overall production of ROS in a broad range of disease states through its ability to degrade heme and to produce carbon monoxide and biliverdin/bilirubin. With the present review we would like to highlight the important antioxidant role of the HO system and especially discuss the contribution of the biliverdin, bilirubin, and biliverdin reductase (BVR) to these beneficial effects. The BVR was reported to confer an antioxidant redox amplification cycle by which low, physiological bilirubin concentrations confer potent antioxidant protection via recycling of biliverdin from oxidized bilirubin by the BVR, linking this sink for oxidants to the NADPH pool. To date the existence and role of this antioxidant redox cycle is still under debate and we present and discuss the pros and cons as well as our own findings on this topic.Frontiers in Pharmacology 03/2012; 3:30. DOI:10.3389/fphar.2012.00030 · 3.80 Impact Factor