Effect of heme oxygenase–endogenous carbon monoxide on mortality during septic shock in rats.
Ontology highlight
ABSTRACT:
SUBMITTER: Yu JB
PROVIDER: S-EPMC2777231 | biostudies-other | 2009 Dec
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Heme oxygenase (HO) enzymes catalyze heme into biliverdin, releasing carbon monoxide (CO) and iron into circulation. These byproducts of heme degradation can have potent cytoprotective effects in the face of stressors such as hypoxia and ischemia-reperfusion events. The potential for exogenous use of CO as a therapeutic agent has received increasing attention throughout the past few decades. Further, HO and CO are noted as putatively adaptive in diving mammals and certain high-altitude human populations that are frequently exposed to hypoxia and/or ischemia-reperfusion events, suggesting that HO and endogenous CO afford an evolutionary advantage for hypoxia tolerance and are critical in cell survival and injury avoidance. Our goal is to describe the importance of examining HO and CO in several systems, the physiological links, and the genetic factors that underlie variation in the HO/CO pathway. Finally, we emphasize the ways in which evolutionary perspectives may enhance our understanding of the HO/CO pathway in the context of diverse clinical settings.
| S-EPMC7387684 | biostudies-literature
Project description:Duchenne muscle dystrophy (DMD) is one of the most common lethal genetic diseases of children worldwide and is 100% fatal. Steroids, the only therapy currently available, are marred by poor efficacy and a high side-effect profile. New therapeutic approaches are urgently needed.Here, we leverage PGC-1?, a powerful transcriptional coactivator known to protect against dystrophy in the mdx murine model of DMD, to search for novel mechanisms of protection against dystrophy.We identify heme oxygenase-1 (HO-1) as a potential novel target for the treatment of DMD. Expression of HO-1 is blunted in the muscles from the mdx murine model of DMD, and further reduction of HO-1 by genetic haploinsufficiency worsens muscle damage in mdx mice. Conversely, induction of HO-1 pharmacologically protects against muscle damage. Mechanistically, HO-1 degrades heme into biliverdin, releasing in the process ferrous iron and carbon monoxide (CO). We show that exposure to a safe low dose of CO protects against muscle damage in mdx mice, as does pharmacological treatment with CO-releasing molecules.These data identify HO-1 and CO as novel therapeutic agents for the treatment of DMD. Safety profiles and clinical testing of inhaled CO already exist, underscoring the translational potential of these observations.
| S-EPMC5126804 | biostudies-literature
Project description:Heme oxygenase-1 (HO-1, encoded by HMOX1) dampens inflammatory reactions via the catabolism of heme into CO, Fe, and biliverdin. We report that expression of HO-1 dictates the pathologic outcome of experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis (MS). Induction of EAE in Hmox1(-/- )C57BL/6 mice led to enhanced CNS demyelination, paralysis, and mortality, as compared with Hmox1(+/+) mice. Induction of HO-1 by cobalt protoporphyrin IX (CoPPIX) administration after EAE onset reversed paralysis in C57BL/6 and SJL/J mice and disease relapse in SJL/J mice. These effects were not observed using zinc protoporphyrin IX, which does not induce HO-1. CoPPIX protection was abrogated in Hmox1(-/-) C57BL/6 mice, indicating that CoPPIX acts via HO-1 to suppress EAE progression. The protective effect of HO-1 was associated with inhibition of MHC class II expression by APCs and inhibition of Th and CD8 T cell accumulation, proliferation, and effector function within the CNS. Exogenous CO mimicked these effects, suggesting that CO contributes to the protective action of HO-1. In conclusion, HO-1 or exposure to its end product CO counters autoimmune neuroinflammation and thus might be used therapeutically to treat MS.
| S-EPMC1770945 | biostudies-literature
Project description:Heme oxygenase-1 (HO-1), a ubiquitous inducible stress-response protein, serves a major metabolic function in heme turnover. HO activity cleaves heme to form biliverdin-IXalpha, carbon monoxide (CO), and iron. Genetic experiments have revealed a central role for HO-1 in tissue homeostasis, protection against oxidative stress, and in the pathogenesis of disease. Four decades of research have witnessed not only progress in elucidating the molecular mechanisms underlying the regulation and function of this illustrious enzyme, but also have opened remarkable translational applications for HO-1 and its reaction products. CO, once regarded as a metabolic waste, can act as an endogenous mediator of cellular signaling and vascular function. Exogenous application of CO by inhalation or pharmacologic delivery can confer cytoprotection in preclinical models of lung/vascular injury and disease, based on anti-apoptotic, anti-inflammatory, and anti-proliferative properties. The bile pigments, biliverdin and bilirubin, end products of heme degradation, have also shown potential as therapeutics in vascular disease based on anti-inflammatory and anti-proliferative activities. Further translational and clinical trials research will unveil whether the HO-1 system or any of its reaction products can be successfully applied as molecular medicine in human disease.
| S-EPMC2742746 | biostudies-literature
Project description:Stress-inducible heme oxygenase-1 (HO-1) catalyzes the oxidative cleavage of heme yielding biliverdin, ferrous iron, and carbon monoxide (CO). Heme oxygenase activity has been attributed to antioxidant defense via the redox cycling system of biliverdin and bilirubin. There is increasing evidence that CO is a gaseous signaling molecule and plays a role in the regulation of energy metabolism. Inhibitory effects of CO on the respiratory chain are well established, but the implication of such a process on the cellular stress response is not well understood. By means of extracellular flux analyses and isotopic tracing, we studied the effects of CO, either released from the CO donor CORM-401 or endogenously produced by heme oxygenases, on the respiratory chain and glucose metabolism. CORM-401 was thereby used as a tool to mimic endogenous CO production by heme oxygenases. In the long term (>60 min), CORM-401-derived CO exposure inhibited mitochondrial respiration, which was compensated by increased glycolysis accompanied by a loss of the ATP production rate and an increase in proton leakage. This effect pattern was likewise observed after endogenous CO production by heme oxygenases. However, in the present setting, these effects were only observed when sufficient substrate for heme oxygenases (hemin) was provided. Modulation of the HO-1 protein level was less important. The long-term influence of CO on glucose metabolism via glycolysis was preceded by a short-term response (<30 min) of the cells to CO. Stable isotope-labeling experiments and metabolic flux analysis revealed a short-term shift of glucose consumption from glycolysis to the pentose phosphate pathway (PPP) along with an increase in reactive oxygen species (ROS) generation. Overall, we suggest that signaling by endogenous CO stimulates the rapid formation of reduction equivalents (NADPH) via the PPP, and plays an additional role in antioxidant defense, e.g., via feed-forward stimulation of the bilirubin/biliverdin redox cycling system.
| S-EPMC7465082 | biostudies-literature
Project description:Critical functions of the immune system are maintained by the ability of myeloid progenitors to differentiate and mature into macrophages. We hypothesized that the cytoprotective gas molecule carbon monoxide (CO), generated endogenously by heme oxygenases (HO), promotes differentiation of progenitors into functional macrophages. Deletion of HO-1, specifically in the myeloid lineage (Lyz-Cre:Hmox1(flfl)), attenuated the ability of myeloid progenitors to differentiate toward macrophages and decreased the expression of macrophage markers, CD14 and macrophage colony-stimulating factor receptor (MCSFR). We showed that HO-1 and CO induced CD14 expression and efficiently increased expansion and differentiation of myeloid cells into macrophages. Further, CO sensitized myeloid cells to treatment with MCSF at low doses by increasing MCSFR expression, mediated partially through a PI3K-Akt-dependent mechanism. Exposure of mice to CO in a model of marginal bone marrow transplantation significantly improved donor myeloid cell engraftment efficiency, expansion and differentiation, which corresponded to increased serum levels of GM-CSF, IL-1? and MCP-1. Collectively, we conclude that HO-1 and CO in part are critical for myeloid cell differentiation. CO may prove to be a novel therapeutic agent to improve functional recovery of bone marrow cells in patients undergoing irradiation, chemotherapy and/or bone marrow transplantation.
| S-EPMC3973235 | biostudies-literature
Project description:The heme oxygenase-1 (HO-1) enzyme system remains an attractive therapeutic target for the treatment of inflammatory conditions. HO-1, a cellular stress protein, serves a vital metabolic function as the rate-limiting step in the degradation of heme to generate carbon monoxide (CO), iron, and biliverdin-IX? (BV), the latter which is converted to bilirubin-IX? (BR). HO-1 may function as a pleiotropic regulator of inflammatory signaling programs through the generation of its biologically active end products, namely CO, BV and BR. CO, when applied exogenously, can affect apoptotic, proliferative, and inflammatory cellular programs. Specifically, CO can modulate the production of proinflammatory or anti-inflammatory cytokines and mediators. HO-1 and CO may also have immunomodulatory effects with respect to regulating the functions of antigen-presenting cells, dendritic cells, and regulatory T cells. Therapeutic strategies to modulate HO-1 in disease include the application of natural-inducing compounds and gene therapy approaches for the targeted genetic overexpression or knockdown of HO-1. Several compounds have been used therapeutically to inhibit HO activity, including competitive inhibitors of the metalloporphyrin series or noncompetitive isoform-selective derivatives of imidazole-dioxolanes. The end products of HO activity, CO, BV and BR may be used therapeutically as pharmacologic treatments. CO may be applied by inhalation or through the use of CO-releasing molecules. This review will discuss HO-1 as a therapeutic target in diseases involving inflammation, including lung and vascular injury, sepsis, ischemia-reperfusion injury, and transplant rejection.
| S-EPMC4857893 | biostudies-literature
Project description:The mechanisms that allow Mycobacterium tuberculosis (Mtb) to persist in human tissue for decades and to then abruptly cause disease are not clearly understood. Regulatory elements thought to assist Mtb to enter such a state include the heme two-component sensor kinases DosS and DosT and the cognate response regulator DosR. We have demonstrated previously that O(2), nitric oxide (NO), and carbon monoxide (CO) are regulatory ligands of DosS and DosT. Here, we show that in addition to O(2) and NO, CO induces the complete Mtb dormancy (Dos) regulon. Notably, we demonstrate that CO is primarily sensed through DosS to induce the Dos regulon, whereas DosT plays a less prominent role. We also show that Mtb infection of macrophage cells significantly increases the expression, protein levels, and enzymatic activity of heme oxygenase-1 (HO-1, the enzyme that produces CO), in an NO-independent manner. Furthermore, exploiting HO-1(+/+) and HO-1(-/-) bone marrow-derived macrophages, we demonstrate that physiologically relevant levels of CO induce the Dos regulon. Finally, we demonstrate that increased HO-1 mRNA and protein levels are produced in the lungs of Mtb-infected mice. Our data suggest that during infection, O(2), NO, and CO are being sensed concurrently rather than independently via DosS and DosT. We conclude that CO, a previously unrecognized host factor, is a physiologically relevant Mtb signal capable of inducing the Dos regulon, which introduces a new paradigm for understanding the molecular basis of Mtb persistence.
| S-EPMC2440631 | biostudies-literature
Project description:BACKGROUND & AIMS:Heme oxygenase-1 (HO-1) and its metabolic by-product, carbon monoxide (CO), protect against intestinal inflammation in experimental models of colitis, but little is known about their intestinal immune mechanisms. We investigated the interactions among CO, HO-1, and the enteric microbiota in mice and zebrafish. METHODS:Germ-free, wild-type, and interleukin (Il)10(-/-) mice and germ-free zebrafish embryos were colonized with specific pathogen-free (SPF) microbiota. Germ-free or SPF-raised wild-type and Il10(-/-) mice were given intraperitoneal injections of cobalt(III) protoporphyrin IX chloride (CoPP), which up-regulates HO-1, the CO-releasing molecule Alfama-186, or saline (control). Colitis was induced in wild-type mice housed in SPF conditions by infection with Salmonella typhimurium. RESULTS:In colons of germ-free, wild-type mice, SPF microbiota induced production of HO-1 via activation of nuclear factor erythroid 2-related factor 2-, IL-10-, and Toll-like receptor-dependent pathways; similar observations were made in zebrafish. SPF microbiota did not induce HO-1 in colons of germ-free Il10(-/-) mice. Administration of CoPP to Il10(-/-) mice before transition from germ-free to SPF conditions reduced their development of colitis. In Il10(-/-) mice, CO and CoPP reduced levels of enteric bacterial genomic DNA in mesenteric lymph nodes. In mice with S typhimurium-induced enterocolitis, CoPP reduced the numbers of live S typhimurium recovered from the lamina propria, mesenteric lymph nodes, spleen, and liver. Knockdown of HO-1 in mouse macrophages impaired their bactericidal activity against E coli, E faecalis, and S typhimurium, whereas exposure to CO or overexpression of HO-1 increased their bactericidal activity. HO-1 induction and CO increased acidification of phagolysosomes. CONCLUSIONS:Colonic HO-1 prevents colonic inflammation in mice. HO-1 is induced by the enteric microbiota and its homeostatic function is mediated, in part, by promoting bactericidal activities of macrophages.
| S-EPMC3608700 | biostudies-literature
Project description:Resolution of acute inflammation is an active event accompanied by biosynthesis of specialized proresolving mediators (SPM). We employed a systems approach to determine the impact of CO in resolution active programs during self-limited inflammation in mice. Compared with ambient air, inhaled CO gas (250 ppm) significantly limited PMN infiltration (?44%, 6 h) into peritoneum and shortened resolution interval from 4 to 2 h. We profiled exudate lipid mediators (LM) via metabololipidomics, CO reduced leukotriene B4 (21 ± 11 versus 59 ± 24 pg/mouse, 6 h), and elevated SPM including resolvin (Rv) D1 (27 ± 4 versus 16 ± 5 pg/mouse) and maresin 1 (26 ± 9 versus 15 ± 3 pg/mouse). With human macrophages, SPM (10 pM-10 nM) elevated heme oxygenase (HO)-1 (?50%, 8 h). CO also enhanced HO-1 expression and accumulation of RvD1 and RvD5, an action reversed by blockage of a key SPM biosynthesis enzyme 15-lipoxygenase type 1. Compared with normoxia, CO increased ?30% phagocytosis of opsonized zymosan with human macrophage, which was further enhanced by SPM (?100%). This CO increased phagocytosis was blocked by 15-lipoxygenase inhibition, and SPM stimulated phagocytosis was diminished by HO-1 inhibition. In murine peritonitis, both pre- and posttreatment with CO inhalation significantly increased macrophages carrying ingested apoptotic PMN in exudates and enhanced PMN apoptosis. Taken together, these results indicate that CO accelerates resolution of acute inflammation, shortens resolution intervals, enhances macrophage efferocytosis, and temporally regulates local levels of lipid mediator/SPM. Moreover, they provide proresolving mechanisms for HO-1/CO, which is part of the SPM-initiated resolution circuit.
| S-EPMC3679316 | biostudies-literature