Alteration of mRNA levels of δ-aminolevulinic acid synthase, ferrochelatase and heme oxygenase-1 in griseofulvin induced protoporphyria mice

1999 ◽  
Vol 19 (3) ◽  
pp. 189-198 ◽  
Author(s):  
K Inafuku
Keyword(s):  
Heme Oxygenase ◽  
Aminolevulinic Acid ◽  
Heme Oxygenase 1 ◽  
Mrna Levels

Effect of Heme Oxygenase-1 Overexpression in Two Models of Lung Inflammation

2003 ◽  
Vol 228 (5) ◽  
pp. 442-446 ◽  
Author(s):  
A. Zampetaki ◽  
T. Minamino ◽  
S.A. Mitsialis ◽  
S. Kourembanas
Keyword(s):  
Transgenic Mice ◽  
Heme Oxygenase ◽  
Lung Inflammation ◽  
Heme Oxygenase 1 ◽  
Mrna Levels ◽  
Wild Type ◽  
Pronounced Increase ◽  
Protein Levels ◽  
Cytokines And Chemokines ◽  
Genetically Engineered Mice

An increasing number of studies implicate heme oxygenase-1 (HO-1) in the regulation of inflammation. Although the mechanisms involved in this cytoprotection are largely unknown, HO-1 and its enzymatic products, carbon monoxide and bilirubin, downregulate the inflammatory response by either attenuating the expression of adhesion molecules and thus inhibiting leukocyte recruitment or by repressing the induction of cytokines and chemokines. In the present study we used genetically engineered mice that express high levels of a human cDNA HO-1 transgene in lung epithelium to assess the effect of HO-1 on lung inflammation. Two separate models of inflammation were studied: hypoxic exposure and lipopolysaccharide (LPS) challenge. We found that both mRNA and protein levels of specific cytokines and chemokines were significantly elevated in response to hypoxia in the lungs of wild-type mice after 2 and 5 days of exposure but significantly suppressed in the hypoxic lungs of transgenic mice, suggesting that inhibition of these cytokines was caused by overexpression of HO-1. However, LPS treatment resulted in a very pronounced increase in mRNA levels of several cytokines in both wild-type and transgenic mice. Despite the high mRNA levels, significantly lower cytokine protein levels were detected in the bronchoalveolar lavage of HO-1 overexpressing mice compared with wild type, indicating that HO-1 leads to repression of cytokines in the airway. These results demonstrate that HO-1 activity operates through distinct molecular mechanisms to confer cytoprotection in the hypoxic and the LPS models of inflammation.

Regulation of heme oxygenase-1 expression by demethoxy curcuminoids through Nrf2 by a PI3-kinase/Akt-mediated pathway in mouse β-cells

2007 ◽  
Vol 293 (3) ◽  
pp. E645-E655 ◽  
Author(s):  
Subbiah Pugazhenthi ◽  
Leonid Akhov ◽  
Gopalan Selvaraj ◽  
Maorong Wang ◽  
Jawed Alam
Keyword(s):  
Signaling Pathways ◽  
Heme Oxygenase ◽  
Nuclear Translocation ◽  
Regulatory Subunit ◽  
Luciferase Reporter ◽  
Heme Oxygenase 1 ◽  
Related Factor ◽  
Mrna Levels ◽  
Phase 2 ◽  
Β Cells

Curcumin (diferuloylmethane), a component of turmeric, has been shown to have therapeutic properties. Induction of phase 2 detoxifying enzymes is a potential mechanism through which some of the actions of curcumin could proceed. Heme oxygenase-1 (HO-1), an antioxidant phase 2 enzyme, has been reported to have cytoprotective effects in pancreatic β-cells. Curcumin on further purification yields demethoxy curcumin (DMC) and bisdemethoxy curcumin (BDMC). The objective of the present study was to determine the mechanism by which these purified curcuminoids induce HO-1 in MIN6 cells, a mouse β-cell line. Demethoxy curcuminoids induced HO-1 promoter linked to the luciferase reporter gene more effectively than curcumin. The induction was dependent on the presence of antioxidant response element (ARE) sites containing enhancer regions (E1 and E2) in HO-1 promoter and nuclear translocation of nuclear factor-E2-related factor (Nrf2), the transcription factor that binds to ARE. Curcuminoids stimulated multiple signaling pathways that are known to induce HO-1. Inhibition of specific signaling pathways with pharmacological inhibitors and cotransfection experiments suggested the involvement of phosphotidylinositol 3-kinase and Akt. Real-time quantitative RT-PCR analysis showed significant elevation in the mRNA levels of HO-1 and two other phase 2 enzymes, the regulatory subunit of glutamyl cysteine ligase, which is needed for the synthesis of glutathione, and NAD(P)H:quinone oxidoreductase, which detoxifies quinones. DMC and BDMC induced the expression of HO-1 and translocated Nrf2 to nucleus in β-cells of mouse islets. Our observations suggest that demethoxy curcuminoids could be used to induce a cellular defense mechanism in β-cells under conditions of stress as seen in diabetes.

Synergistic Up-Regulation of Heme Oxygenase-1 in Human Liver by Heme and siRNA to Bach1:Possible Therapeutic Implications.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1633-1633
Author(s):  
Tahereh Ghaziani ◽  
Ying Shan ◽  
Richard W. Lambrecht ◽  
Herbert L. Bonkovsky
Keyword(s):  
Gene Expression ◽  
Heme Oxygenase ◽  
Ischemia Reperfusion Injury ◽  
Tissue Injury ◽  
Ischemia Reperfusion ◽  
Negative Regulator ◽  
Heme Oxygenase 1 ◽  
Significant Finding ◽  
Mrna Levels ◽  
Protein Levels

Abstract Background: Heme oxygenase-1 (HO-1) is an antioxidant defense enzyme that converts toxic heme into antioxidants. HO-1 is strongly up-regulated by its physiologic substrate, heme, which is currently the treatment of choice for acute attacks of porphyria and which may have other therapeutic uses, as well (e.g., for cytoprotection or amelioration of ischemia/reperfusion injury by increasing supply of carbon monoxide, biliverdin, or bilirubin). Up-regulation of HO-1 expression has been associated with increased resistance to tissue injury. Bach1 is a bZip protein which forms heterodimers with small Maf proteins. HO-1 is expressed at higher levels in tissues of Bach1-deficient mice, indicating that Bach1 acts as a negative regulator of the mouse HO-1 gene. The molecular mechanism that confers repression of HO-1 by Bach1, and whether there are similar effects in human cells, has remained elusive. The aim of this study was to assess whether modulation of human hepatic Bach1 expression by siRNA technology influences HO-1 gene expression and whether such gene silencing would enhance the inducing effects of heme on HO-1. Methods: siRNAs targeted 4 different positions of human Bach1 mRNA were designed and synthesized. We transfected Bach1-siRNA (25–200 nM) into Huh-7 cells using Lipofectamine for 24–72 h, after which, cells were treated with or without heme. We quantified HO-1 and Bach1 mRNA and protein levels by quantitative RT-PCR and western blotting, respectively. Effects and specificity of Bach1-siRNA were analyzed and compared with those of non-Bach1 related siRNAs (non-specific control-duplex (NSCD) and LaminB2-siRNA). Results: Bach1-siRNAs (25–200 nM) transfected into Huh-7 cells for 24–72 h significantly reduced Bach1 mRNA and protein levels approximately 80%, compared with non siRNA treated cells. In contrast, transfection with same amounts of NSCD or LaminB2 siRNA did not reduce Bach1 mRNA or protein levels, confirming the specificity of Bach1-siRNA in Huh-7 cells. A significant finding of these studies was the 7-fold up-regulation of the HO-1 gene in Bach1-siRNA transfected cells, compared to cells without Bach1-siRNA or those transfected with NSCD or LaminB2. Bach1, NSCD, and LaminB2 siRNAs had no effect on HO-2 or 5-aminolevulinate synthase-1 mRNA levels (two genes that are not induced by heme). The effects of increasing concentrations of heme (up to 10 μM) in the presence or absence of Bach1-siRNA on the levels of HO-1 mRNA expression are shown in the Figure. For all of the heme concentrations tested, the levels of HO-1 mRNA were greater when Bach1 siRNA was present. Conclusions: Bach1 has a specific and selective effect to repress expression of human hepatic HO-1. Silencing of the Bach1 gene by siRNAs may be a useful method for up-regulating HO-1 gene expression. The combination of intravenous heme and Bach1 silencing may be useful for therapy of acute porphyrias in relapse or other conditions in which up-regulation of HO-1 may be beneficial. (Supported by grants from NIH [DK38825] and Ovation Pharmaceuticals, Inc.) Figure Figure

Increased Heme Oxygenase-1 Gene Expression in the Livers of Patients with Portal Hypertension Due to Severe Hepatic Cirrhosis

2002 ◽  
Vol 30 (3) ◽  
pp. 282-288 ◽  
Author(s):  
M Matsumi ◽  
T Takahashi ◽  
H Fujii ◽  
I Ohashi ◽  
R Kaku ◽  
...  
Keyword(s):  
Gene Expression ◽  
Carbon Monoxide ◽  
Portal Hypertension ◽  
Heme Oxygenase ◽  
Anaesthetic Management ◽  
Heme Oxygenase 1 ◽  
Mrna Levels ◽  
Hepatic Transplantation ◽  
Aminolevulinate Synthase ◽  
Surgical Bleeding

Surgical bleeding associated with splanchnic hyperaemia due to portal hypertension complicates the anaesthetic management of hepatic transplantation. Although the mechanism(s) of portal hypertension are not fully understood, carbon monoxide, a product of the heme oxygenase (HO) reaction, is thought to be one of the endogenous vasodilators in the liver. In this study, the expression of mRNA encoding inducible HO isozyme (HO-1) in the livers of patients with portal hypertension undergoing hepatic transplantation was determined in comparison with those without portal hypertension. HO-1 mRNA levels were significantly greater in the portal hypertension group than in the group without portal hypertension. In contrast with HO-1, the gene expression of non-specific δ-aminolevulinate synthase (ALAS-N), which is down-regulated by heme in the liver, was the same in both groups. These results suggest that HO-1 is up-regulated through heme-independent stimuli according to the development of portal hypertension, and that induced HO-1 plays a pathophysiological role in portal hypertension through carbon monoxide production.

5-Aminolevulinic acid combined with ferrous iron enhances the expression of heme oxygenase-1

2014 ◽  
Vol 19 (2) ◽  
pp. 300-307 ◽  
Author(s):  
Yoshiaki Nishio ◽  
Masayuki Fujino ◽  
Mingyi Zhao ◽  
Takuya Ishii ◽  
Masahiro Ishizuka ◽  
...  
Keyword(s):  
Heme Oxygenase ◽  
Ferrous Iron ◽  
Aminolevulinic Acid ◽  
Heme Oxygenase 1

Methemoglobin is a potent activator of endothelial cells by stimulating IL-6 and IL-8 production and E-selectin membrane expression

2003 ◽  
Vol 285 (5) ◽  
pp. C1036-C1046 ◽  
Author(s):  
Xueying Liu ◽  
Zoltán Spolarics
Keyword(s):  
Endothelial Cells ◽  
Cell Adhesion ◽  
Heme Oxygenase ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Heme Oxygenase 1 ◽  
Zinc Protoporphyrin ◽  
Mrna Levels ◽  
Induced Responses ◽  
Membrane Expression

Infection and injury are frequently accompanied by hemolysis. Endothelial cells are direct targets of free Hb or its oxidative derivatives, including methemoglobin (MHb) and hemin. This study tested whether Hb or its derivatives alter chemokine (IL-8) and cytokine (IL-6) production and the membrane expression of cell adhesion molecule (E-selectin) in human umbilical vein endothelial cells ( passages 2-4, HUVECs). E-selectin membrane content and IL-6 and IL-8 release were quantified by ELISA; cellular mRNA levels were determined by RT-PCR. MHb in vitro resulted in a dose (1-50 μM)- and time (2-16 h)-dependent increase in E-selectin membrane content and IL-6 and IL-8 release in HUVECs. The stimulatory effect of MHb (12 μM) on E-selectin membrane expression and IL-6 and IL-8 release was similar to that produced after treatment with TNF-α (5 ng/ml) and IL-1β (0.25 ng/ml). In contrast, Hb or hemin had no effects. As expected, MHb, Hb, and hemin markedly induced heme oxygenase-1 expression in HUVECs. Haptoglobin, cytochalasin D, and actinomycin inhibited the MHb-induced responses, whereas zinc protoporphyrin IX (a heme oxygenase inhibitor) or desferroxamine (an iron chelator) did not inhibit MHb-induced responses. MHb also increased cellular mRNA levels of E-selectin, IL-6, and IL-8. MHb treatment activated cellular NF-κB and NF-κB inhibitors; N-acetyl cysteine, SN50, and caffeic acid phenylethyl ester inhibited the MHb-induced responses. These data indicate that MHb is a potent activator of endothelial cells through NF-κB-mediated upregulation of cell adhesion molecule expression and chemokine and cytokine production. MHb-induced endothelial cell activation may have clinical significance after infections, hemolysis, or methemoglobinemia.

Regulation of Heme Oxygenase-1 Gene Expression by Anoxia and Reoxygenation in Primary Rat Hepatocyte Cultures

2003 ◽  
Vol 228 (5) ◽  
pp. 584-589 ◽  
Author(s):  
Andreas Ohlmann ◽  
Susanne Giffhorn-Katz ◽  
Ivonne Becker ◽  
Norbert Katz ◽  
Stephan Immenschuh
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Heme Oxygenase ◽  
Heme Oxygenase 1 ◽  
Protein Synthesis Inhibitor ◽  
Mrna Levels ◽  
Rat Hepatocyte ◽  
Hsp70 Mrna ◽  
Hepatocyte Cultures ◽  
Antioxidant Agents

Heme oxygenase (HO) catalyzes the rate-limiting enzymatic step of heme degradation and regulates the cellular heme content. Gene expression of the inducible isoform of HO, HO-1, is upregulated in response to various oxidative stress stimuli. To investigate the regulatory role of anoxia and reoxygenation (A/R) on hepatic HO-1 gene expression, primary cultures of rat hepatocytes were exposed after an anoxia of 4 hr to normal oxygen tension for various lengths of time. For comparison, gene expression of the noninducible HO isoform, HO-2, and that of the heat-shock protein 70 (HSP70) were determined. During reoxygenation, a marked increase of HO-1 and HSP70 steady-state mRNA levels was observed, whereas no alteration of HO-2 mRNA levels occurred. Corresponding to HO-1 mRNA, an increase of HO-1 protein expression was determined by Western blot analysis. The anoxia-dependent induction of HO-1 was prevented by pretreatment with the transcription inhibitor, actinomycin D, but not by the protein synthesis inhibitor, cycloheximide, suggesting a transcriptional regulatory mechanism. After exposure of hepatocytes to anoxia, the relative levels of oxidized glutathione increased within the first 40 min of reoxygenation. Pretreament of cell cultures with the antioxidant agents, β-carotene and allopurinol, before exposure to A/R led to a marked decrease of HO-1 and HSP70 mRNA expression during reoxygenation. An even more pronounced reduction of mRNA expression was observed after exposure to desferrioxamine. Taken together, the data demonstrate that HO-1 gene expression in rat hepatocyte cultures after A/R is upregulated by a transcriptional mechanism that may be, in part, mediated via the generation of ROS and the glutathione system.

scholarly journals Regulation of heme oxygenase-1 gene by peptidoglycan involves the interaction of Elk-1 and C/EBPα to increase expression

2010 ◽  
Vol 298 (6) ◽  
pp. L870-L879 ◽  
Author(s):  
Chi-Chih Hung ◽  
Xiaoli Liu ◽  
Min-Young Kwon ◽  
Young-Ho Kang ◽  
Su Wol Chung ◽  
...  
Keyword(s):  
Heme Oxygenase ◽  
Promoter Activity ◽  
Inflammatory Responses ◽  
Systemic Infection ◽  
Protective Role ◽  
Heme Oxygenase 1 ◽  
Mrna Levels ◽  
Gram Positive ◽  
And Function

Heme oxygenase (HO)-1 is a cytoprotective enzyme with anti-inflammatory properties. HO-1 is induced during a systemic inflammatory response, and expression of HO-1 is beneficial during sepsis of a Gram-positive source. Systemic infection from Gram-positive organisms has emerged as an important cause of sepsis, with Staphylococcus aureus as a common etiology. An important mediator of Gram-positive infections is peptidoglycan (PGN), a cell wall component of these organisms. Here, we demonstrate that HO-1 played an important, protective role in vivo, as mice deficient in HO-1 were very sensitive to the lethal effects of PGN derived from S. aureus. PGN induced HO-1 protein and mRNA levels, and this regulation occurred at the level of gene transcription. The PGN-responsive region of the HO-1 promoter (from −117 to −66 bp) contains a functional EBS, and Ets proteins are known to be involved in the regulation of inflammatory responses. We showed previously that Ets factors (activators Ets-2 and Ets-1 and repressor Elk-3) regulate HO-1 expression by Gram-negative endotoxin. However, during exposure to a Gram-positive stimulus in the present study, Elk-1 was a potent activator of HO-1 in conjunction with PGN. The ability of Elk-1 to induce HO-1 promoter activity was independent of direct DNA binding, but rather occurred by interacting with the CCAAT/enhancer-binding protein-α (C/EBPα), which binds to DNA. Moreover, silencing of C/EBPα in macrophages prevented induction of HO-1 promoter activity by either Elk-1 or PGN. These data provide further insight into the regulation and function of HO-1 by a mediator of Gram-positive bacteria.

scholarly journals Heme Oxygenase-1 Couples Activation of Mitochondrial Biogenesis to Anti-inflammatory Cytokine Expression

2011 ◽  
Vol 286 (18) ◽  
pp. 16374-16385 ◽  
Author(s):  
Claude A. Piantadosi ◽  
Crystal M. Withers ◽  
Raquel R. Bartz ◽  
Nancy Chou MacGarvey ◽  
Ping Fu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Heme Oxygenase ◽  
Mitochondrial Biogenesis ◽  
Inflammatory Cytokine ◽  
Cytokine Expression ◽  
Heme Oxygenase 1 ◽  
Mrna Levels ◽  
Promoter Regions ◽  
Anti Inflammatory ◽  
Anti Inflammatory Cytokine

The induction of heme oxygenase-1 (HO-1; Hmox1) by inflammation, for instance in sepsis, is associated both with an anti-inflammatory response and with mitochondrial biogenesis. Here, we tested the idea that HO-1, acting through the Nfe2l2 (Nrf2) transcription factor, links anti-inflammatory cytokine expression to activation of mitochondrial biogenesis. HO-1 induction after LPS stimulated anti-inflammatory IL-10 and IL-1 receptor antagonist (IL-1Ra) expression in mouse liver, human HepG2 cells, and mouse J774.1 macrophages but blunted tumor necrosis factor-α expression. This was accompanied by nuclear Nfe2l2 accumulation and led us to identify abundant Nfe2l2 and other mitochondrial biogenesis transcription factor binding sites in the promoter regions of IL10 and IL1Ra compared with pro-inflammatory genes regulated by NF-κΒ. Mechanistically, HO-1, through its CO product, enabled these transcription factors to bind the core IL10 and IL1Ra promoters, which for IL10 included Nfe2l2, nuclear respiratory factor (NRF)-2 (Gabpa), and MEF2, and for IL1Ra, included NRF-1 and MEF2. In cells, Hmox1 or Nfe2l2 RNA silencing prevented IL-10 and IL-1Ra up-regulation, and HO-1 induction failed post-LPS in Nfe2l2-silenced cells and post-sepsis in Nfe2l2−/− mice. Nfe2l2−/− mice compared with WT mice, showed more liver damage, higher mortality, and ineffective CO rescue in sepsis. Nfe2l2−/− mice in sepsis also generated higher hepatic TNF-α mRNA levels, lower NRF-1 and PGC-1α mRNA levels, and no enhancement of anti-inflammatory Il10, Socs3, or bcl-xL gene expression. These findings disclose a highly structured transcriptional network that couples mitochondrial biogenesis to counter-inflammation with major implications for immune suppression in sepsis.

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