Search results for "HEME OXYGENASE-1"
showing 10 items of 57 documents
Carbon monoxide: mechanisms of action and potential clinical implications.
2013
International audience; Small amounts of carbon monoxide (CO) are continuously produced in mammals. The intracellular levels of CO can increase under stressful conditions following the induction of HO-1 (heme oxygnase-1), a ubiquitous enzyme responsible for the catabolism of heme. Unlike nitric oxide, which is a free radical, CO does not contain free electrons but may be involved in oxidative stress. The carbonate radical has been proposed to be a key mediator of oxidative damage resulting from peroxynitrite production, likewise, the precursor of the carbonate radical anion being bicarbonate and carbon dioxide. We report herein some of the transcription factors and protein kinases involved …
Haem oxygenase-1 regulates catabolic and anabolic processes in osteoarthritic chondrocytes
2007
Pro-inflammatory cytokines, matrix metalloproteinases (MMPs) and other catabolic factors participate in the pathogenesis of cartilage damage in osteoarthritis (OA). Pro-inflammatory cytokines such as interleukin-1β (IL-1β) mediate cartilage degradation and might be involved in the progression of OA. Previously, we found that haem oxygenase-1 (HO-1) is down-regulated by pro-inflammatory cytokines and up-regulated by IL-10 in OA chondrocytes. The aim of this study was to determine whether HO-1 can modify the catabolic effects of IL-1β in OA cartilage and chondrocytes. Up-regulation of HO-1 by cobalt protoporphyrin IX significantly reduced glycosaminoglycan degradation elicited by IL-1β in OA …
Haem oxygenase-1 induction reverses the actions of interleukin-1β on hypoxia-inducible transcription factors and human chondrocyte metabolism in hypo…
2013
HO-1 (haem oxygenase-1) catalyses the degradation of haem and possesses anti-inflammatory and cytoprotective properties. The role of inflammatory mediators in the pathogenesis of OA (osteoarthritis) is becoming increasingly appreciated. In the present study, we investigated the effects of HO-1 induction in OA and healthy HACs (human articular chondrocytes) in response to inflammatory cytokine IL-1 β (interleukin-1β) under hypoxic conditions. Hypoxia was investigated as it is a more physiological condition of the avascular cartilage. Hypoxic signalling is mediated by HIFs (hypoxia-inducible factors), of which there are two main isoforms, HIF-1α and HIF-2α. Normal and OA chondrocytes were sti…
The Role of the Heme Oxygenase System in the Metabolic Syndrome
2014
Molecular chaperones and the heat shock response play a major role in the maintenance of cellular homeostasis under various pathological conditions. In particular, their role is to regulate protein conformation, protect proteins from misfolding and aggregation, and maintain signalling and organellarnetworks. Among variousheat shock proteins, Hsp32 also known as heme oxygenase-1 (HO-1), has demonstrated an important role in metabolic syndrome. In particular, the HO system seems to play a major role in the complex pathophysiological cascade involved in insulin resistance mechanisms, and adipocyte functions as measured by the release of important adipokynes. The aim of the present review is to…
Anti-inflammatory actions of the heme oxygenase-1 pathway.
2003
Heme oxygenase 1 (HO-1) is induced by oxidative or nitrosative stress, cytokines and other mediators produced during inflammatory processes, likely as part of a defence system in cells exposed to stress to provide a negative feedback for cell activation and the production of mediators, which could modulate the inflammatory response. HO-1 activity results in the inhibition of oxidative damage and apoptosis, with significant reductions in inflammatory events including edema, leukocyte adhesion and migration, and production of inflammatory cytokines. HO-1 is induced by nitric oxide (NO) in different biological systems and can control the increased production of this mediator observed in many i…
Heme oxygenase-1 inhibits apoptosis in Caco-2 cells via activation of Akt pathway
2005
Heme oxygenase-1 can play a protective role against cellular stress. In colon cancer cells, these effects would be relevant to oncogenesis and resistance to chemotherapy. The aim of the study was to examine the effects of heme oxygenase-1 induction on cell survival in a human colon cancer cell line, Caco-2. Serum deprivation induced apoptosis, reduced Akt and p38 phosphorylation, and increased p21(Cip/WAF1) levels. Heme oxygenase-1 induction by treatment with cobalt protoporphyrin IX resulted in resistance to apoptosis, activation of Akt, reduction in p21(Cip/WAF1) levels and modification of bcl2/bax ratio towards survival. Indomethacin reduced apoptosis but in contrast to heme oxygenase-1,…
Redox regulation of genome stability by effects on gene expression, epigenetic pathways and DNA damage/repair
2015
Reactive oxygen and nitrogen species (e.g. H2O2, nitric oxide) confer redox regulation of essential cellular signaling pathways such as cell differentiation, proliferation, migration and apoptosis. In addition, classical regulation of gene expression or activity, including gene transcription to RNA followed by translation to the protein level, by transcription factors (e.g. NF-κB, HIF-1α) and mRNA binding proteins (e.g. GAPDH, HuR) is subject to redox regulation. This review will give an update of recent discoveries in this field, and specifically highlight the impact of reactive oxygen and nitrogen species on DNA repair systems that contribute to genomic stability. Emphasis will be placed …
Intensified oxidative and nitrosative stress following combined ALA-based photodynamic therapy and local hyperthermia in rat tumors.
2003
Oxidative stress-related changes in tumors upon localized hyperthermia (HT), 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) and their combination (ALA+HT) were examined after the observation that the antitumor effects of ALA-PDT could be significantly enhanced upon simultaneous application of HT. Rats bearing s.c. DS-sarcomas (0.6–1.0 ml) on the hind foot dorsum were anesthetized and underwent one of the following treatments: (i) ALA-PDT (375 mg/kg 5-ALA i.v.); (ii) localized HT, 43°C for 60 min; (iii) combined ALA-PDT and HT [=ALA+HT]. Appropriate control experiments were also performed. After treatment, tumors were excised and rapidly frozen for later analysis of nitrosative s…
Beneficial effects of heme oxygenase-1 up-regulation in the development of experimental inflammation induced by zymosan.
2003
Heme oxygenase-1 (HO-1) is part of the integrated response to oxidative stress. This enzyme may exert anti-inflammatory effects in some animal models, although the precise mechanisms are not fully understood. We have examined the role of HO-1 in the inflammatory response induced by zymosan in the mouse air pouch. Zymosan administration induced HO-1 protein expression in leukocytes migrating to exudates, with maximal levels in the late phase of this response (24-48 h). This was accompanied by ferritin induction and bilirubin accumulation, indicating that this enzyme is active in our model. HO-1 expression by zymosan treatment was partly reduced by aminoguanidine, suggesting the participation…
Conversion of biliverdin to bilirubin by biliverdin reductase contributes to endothelial cell protection by heme oxygenase-1—evidence for direct and …
2009
Heme oxygenase-1 (HO-1) is highly protective in various pathophysiological states such as cardiovascular and neurodegenerative diseases. HO-1-derived bilirubin is an efficient scavenger of reactive oxygen and nitrogen species (RONS). It remains to determine whether conversion of biliverdin to bilirubin is an essential step for HO-1-conferred protection of endothelial cells. RONS scavenging activities of biliverdin versus bilirubin were assessed by different RONS generating systems and detection techniques. We also silenced the biliverdin reductase (BVR) or HO-1 gene in cultured primary human endothelial cells (HUVECs) and measured the effect on RONS formation upon stimulation with lipopolys…