Heme Oxygenase-1 is an Essential Cytoprotective Component in Oxidative Tissue Injury Induced by Hemorrhagic Shock

Excess transforming growth factor-β1 (TGF-β1) in the kidney leads to increased cell proliferation and deposition of extracellular matrix, resulting in progressive kidney fibrosis. TGF-β1, however, stabilizes and attenuates tissue injury through the activation of cytoprotective proteins, including heme oxygenase-1 (HO-1). HO-1 catabolizes pro-oxidant heme into substances with anti-oxidant, anti-apoptotic, anti-fibrogenic, vasodilatory and immune modulatory properties. Little is known regarding the molecular regulation of human HO-1 induction by TGF-β1 except that it is dependent on de novo RNA synthesis and requires a group of structurally related proteins called Smads. It is not known whether other DNA binding proteins are required to initiate transcription of HO-1 and, furthermore, the promoter region(s) involved in TGF-β1-mediated induction of HO-1 has not been identified. The purpose of this study was to further delineate the molecular regulation of HO-1 by TGF-β1 in human renal proximal tubular cells. Actinomycin D and nuclear run-on studies demonstrate that TGF-β1 augments HO-1 expression by increased gene transcription and does not involve increased mRNA stability. Using transient transfection, mithramycin A, small interfering RNA, electrophoretic mobility shift assays, and decoy oligonucleotide experiments, a TGF-β1-responsive region is identified between 9.1 and 9.4 kb of the human HO-1 promoter. This ∼280-bp TGF-β1-responsive region contains a putative Smad binding element and specificity protein 1 binding sites, both of which are required for human HO-1 induction by TGF-β1.

Download Full-text

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

Blood ◽

10.1182/blood.v104.11.1633.1633 ◽

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

Download Full-text

HEMIN ARGINATE-INDUCED HEME OXYGENASE 1 EXPRESSION IMPROVES LIVER MICROCIRCULATION AND MEDIATES AN ANTI-INFLAMMATORY CYTOKINE RESPONSE AFTER HEMORRHAGIC SHOCK

Shock ◽

10.1097/shk.0b013e318157e526 ◽

2007 ◽

pp. 1 ◽

Cited By ~ 1

Author(s):

Darius Kubulus ◽

Alexander Mathes ◽

Sascha Pradarutti ◽

Alexander Raddatz ◽

Jochen Heiser ◽

...

Keyword(s):

Hemorrhagic Shock ◽

Heme Oxygenase ◽

Inflammatory Cytokine ◽

Cytokine Response ◽

Heme Oxygenase 1 ◽

Liver Microcirculation ◽

Inflammatory Cytokine Response ◽

Anti Inflammatory ◽

Anti Inflammatory Cytokine

Download Full-text

Complement factor 3 deficiency attenuates hemorrhagic shock-related hepatic injury and systemic inflammatory response syndrome

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00282.2010 ◽

2010 ◽

Vol 299 (5) ◽

pp. R1175-R1182 ◽

Cited By ~ 19

Author(s):

Changchun Cai ◽

Roop Gill ◽

Hyun-Ae Eum ◽

Zongxian Cao ◽

Patricia A. Loughran ◽

...

Keyword(s):

Inflammatory Response ◽

Hemorrhagic Shock ◽

Complement Activation ◽

Tissue Injury ◽

Soft Tissue Injury ◽

High Mobility ◽

Organ Damage ◽

Heme Oxygenase 1 ◽

Complement Factor ◽

Wild Type

Although complement activation is known to occur in the setting of severe hemorrhagic shock and tissue trauma (HS/T), the extent to which complement drives the initial inflammatory response and end-organ damage is uncertain. In this study, complement factor 3-deficient (C3−/−) mice and wild-type control mice were subjected to 1.5-h hemorrhagic shock, bilateral femur fracture, and soft tissue injury, followed by 4.5-h resuscitation (HS/T). C57BL/6 mice were also given 15 U of cobra venom factor (CVF) or phosphate-buffered saline injected intraperitoneally, followed by HS/T 24 h later. The results showed that HS/T resulted in C3 consumption in wild-type mice and C3 deposition in injured livers. C3−/− mice had significantly lower serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and circulating DNA levels, together with much lower circulating interleukin (IL)-6, IL-10, and high-mobility group box 1 (HMGB1) levels. Temporary C3 depletion by CVF preconditioning also led to reduced transaminases and a blunted cytokine release. C3−/− mice displayed well-preserved hepatic structure. C3−/− mice subjected to HS/T had higher levels of heme oxygenase-1, which has been associated with tissue protection in HS models. Our data indicate that complement activation contributes to inflammatory pathways and liver damage in HS/T. This suggests that targeting complement activation in the setting of severe injury could be useful.

Download Full-text

KUPFFER CELLS AND NEUTROPHILS AS PARACRINE REGULATORS OF THE HEME OXYGENASE-1 GENE IN HEPATOCYTES AFTER HEMORRHAGIC SHOCK

Shock ◽

10.1097/00024382-200115060-00005 ◽

2001 ◽

Vol 15 (6) ◽

pp. 438-445 ◽

Cited By ~ 27

Author(s):

Markus Paxian ◽

Hauke Rensing ◽

Andreas Rickauer ◽

Sandra Schönhofen ◽

Joachim Schmeck ◽

...

Keyword(s):

Hemorrhagic Shock ◽

Heme Oxygenase ◽

Kupffer Cells ◽

Heme Oxygenase 1

Download Full-text

Dobutamine Improves Liver Function after Hemorrhagic Shock through Induction of Heme Oxygenase-1

American Journal of Respiratory and Critical Care Medicine ◽

10.1164/rccm.200508-1221oc ◽

2006 ◽

Vol 174 (2) ◽

pp. 198-207 ◽

Cited By ~ 22

Author(s):

Alexander Raddatz ◽

Darius Kubulus ◽

Johannes Winning ◽

Inge Bauer ◽

Sascha Pradarutti ◽

...

Keyword(s):

Liver Function ◽

Hemorrhagic Shock ◽

Heme Oxygenase ◽

Heme Oxygenase 1

Download Full-text

Therapeutic Potential of Heme Oxygenase-1 in Aneurysmal Diseases

Antioxidants ◽

10.3390/antiox9111150 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1150

Author(s):

Wei-Cheng Jiang ◽

Chen-Mei Chen ◽

Candra D. Hamdin ◽

Alexander N. Orekhov ◽

Igor A. Sobenin ◽

...

Keyword(s):

Oxidative Stress ◽

Heme Oxygenase ◽

Therapeutic Potential ◽

Tissue Injury ◽

Aneurysmal Subarachnoid Hemorrhage ◽

Vascular Diseases ◽

High Rate ◽

Heme Oxygenase 1 ◽

High Morbidity ◽

Attractive Option

Abdominal aortic aneurysm (AAA) and intracranial aneurysm (IA) are serious arterial diseases in the aorta and brain, respectively. AAA and IA are associated with old age in males and females, respectively, and if rupture occurs, they carry high morbidity and mortality. Aneurysmal subarachnoid hemorrhage (SAH) due to IA rupture has a high rate of complication and fatality. Despite these severe clinical outcomes, preventing or treating these devastating diseases remains an unmet medical need. Inflammation and oxidative stress are shared pathologies of these vascular diseases. Therefore, therapeutic strategies have focused on reducing inflammation and reactive oxygen species levels. Interestingly, in response to cellular stress, the inducible heme oxygenase-1 (HO-1) is highly upregulated and protects against tissue injury. HO-1 degrades the prooxidant heme and generates molecules with antioxidative and anti-inflammatory properties, resulting in decreased oxidative stress and inflammation. Therefore, increasing HO-1 activity is an attractive option for therapy. Several HO-1 inducers have been identified and tested in animal models for preventing or alleviating AAA, IA, and SAH. However, clinical trials have shown conflicting results. Further research and the development of highly selective HO-1 regulators may be needed to prevent the initiation and progression of AAA, IA, or SAH.

Download Full-text

An internal enhancer regulates heme- and cadmium-mediated induction of human heme oxygenase-1

AJP Renal Physiology ◽

10.1152/ajprenal.00137.2003 ◽

2003 ◽

Vol 285 (3) ◽

pp. F515-F523 ◽

Cited By ~ 56

Author(s):

Nathalie Hill-Kapturczak ◽

Eric Sikorski ◽

Christy Voakes ◽

Jairo Garcia ◽

Harry S. Nick ◽

...

Keyword(s):

Heme Oxygenase ◽

Tissue Injury ◽

Molecular Regulation ◽

Heme Oxygenase 1 ◽

Aortic Endothelial Cells ◽

Rate Limiting Step ◽

Limiting Step ◽

Beneficial Response ◽

Enhancer Function ◽

Rate Limiting

Heme oxygenase-1 (HO-1) catalyzes the rate-limiting step in heme degradation, releasing iron, carbon monoxide, and biliverdin. Induction of HO-1 is an adaptive and beneficial response in renal and nonrenal settings of tissue injury. The purpose of this study was to characterize the regulation of the human HO-1 gene in renal proximal tubule and aortic endothelial cells in response to heme and cadmium. Evaluation of multiple human HO-1 promoter-reporter constructs up to -9.1 kb demonstrated only a partial response to heme and cadmium. In an effort to mimic endogenous stimulus-dependent levels of HO-1 induction, we evaluated the entire 12.5 kb of the human HO-1 gene, including introns and exons, in conjunction with a -4.5-kb human HO-1 promoter and observed significant heme- and cadmium-mediated induction of the reporter gene, suggesting the presence of an internal enhancer. Enhancer function was orientation independent and required a region between -3.5 and -4.5 kb of the human HO-1 promoter. Our studies identified a novel enhancer internal to the human HO-1 gene that, in conjunction with the HO-1 promoter, recapitulates heme- and cadmium-mediated induction of the endogenous HO-1 gene. Elucidation of the molecular regulation of the human HO-1 gene will allow for the development of therapeutic strategies to manipulate HO-1 gene expression in pathological states.

Download Full-text