Heme oxygenase 1 protects human colonocytes against ROS formation, oxidative DNA damage and cytotoxicity induced by heme iron, but not inorganic iron

Abstract The consumption of red meat is probably carcinogenic to humans and is associated with an increased risk to develop colorectal cancer (CRC). Red meat contains high amounts of heme iron, which is thought to play a causal role in tumor formation. In this study, we investigated the genotoxic and cytotoxic effects of heme iron (i.e., hemin) versus inorganic iron in human colonic epithelial cells (HCEC), human CRC cell lines and murine intestinal organoids. Hemin catalyzed the formation of reactive oxygen species (ROS) and induced oxidative DNA damage as well as DNA strand breaks in both HCEC and CRC cells. In contrast, inorganic iron hardly affected ROS levels and only slightly increased DNA damage. Hemin, but not inorganic iron, caused cell death and reduced cell viability. This occurred preferentially in non-malignant HCEC, which was corroborated in intestinal organoids. Both hemin and inorganic iron were taken up into HCEC and CRC cells, however with differential kinetics and efficiency. Hemin caused stabilization and nuclear translocation of Nrf2, which induced heme oxygenase-1 (HO-1) and ferritin heavy chain (FtH). This was not observed after inorganic iron treatment. Chemical inhibition or genetic knockdown of HO-1 potentiated hemin-triggered ROS generation and oxidative DNA damage preferentially in HCEC. Furthermore, HO-1 abrogation strongly augmented the cytotoxic effects of hemin in HCEC, revealing its pivotal function in colonocytes and highlighting the toxicity of free intracellular heme iron. Taken together, this study demonstrated that hemin, but not inorganic iron, induces ROS and DNA damage, resulting in a preferential cytotoxicity in non-malignant intestinal epithelial cells. Importantly, HO-1 conferred protection against the detrimental effects of hemin.

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Loss of Gadd45a does not modify the pulmonary response to oxidative stress

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00355.2004 ◽

2005 ◽

Vol 288 (4) ◽

pp. L663-L671 ◽

Cited By ~ 6

Author(s):

Jason M. Roper ◽

Sean C. Gehen ◽

Rhonda J. Staversky ◽

M. Christine Hollander ◽

Albert J. Fornace ◽

...

Keyword(s):

Oxidative Stress ◽

Dna Damage ◽

Epithelial Cells ◽

Oxidative Dna Damage ◽

Genotoxic Stress ◽

Clara Cell ◽

Heme Oxygenase 1 ◽

Alveolar Type ◽

Type I ◽

Type Ii

It is well established that exposure to high levels of oxygen (hyperoxia) injures and kills microvascular endothelial and alveolar type I epithelial cells. In contrast, significant death of airway and type II epithelial cells is not observed at mortality, suggesting that these cell types may express genes that protect against oxidative stress and damage. During a search for genes induced by hyperoxia, we previously reported that airway and alveolar type II epithelial cells uniquely express the growth arrest and DNA damage ( Gadd) 45a gene. Because Gadd45a has been implicated in protection against genotoxic stress, adult Gadd45a (+/+) and Gadd45a (−/−) mice were exposed to hyperoxia to investigate whether it protected epithelial cells against oxidative stress. During hyperoxia, Gadd45a deficiency did not affect loss of airway epithelial expression of Clara cell secretory protein or type II epithelial cell expression of pro-surfactant protein C. Likewise, Gadd45a deficiency did not alter recruitment of inflammatory cells, edema, or overall mortality. Consistent with Gadd45a not affecting the oxidative stress response, p21Cip1/WAF1 and heme oxygenase-1 were comparably induced in Gadd45a (+/+) and Gadd45a (−/−) mice. Additionally, Gadd45a deficiency did not affect oxidative DNA damage or apoptosis as assessed by oxidized guanine and terminal deoxyneucleotidyl transferase-mediated dUTP nick-end labeling staining. Overexpression of Gadd45a in human lung adenocarcinoma cells did not affect viability or survival during exposure, whereas it was protective against UV-radiation. We conclude that increased tolerance of airway and type II epithelial cells to hyperoxia is not attributed solely to expression of Gadd45a.

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MicroRNA-760 resists ambient PM2.5-induced apoptosis in human bronchial epithelial cells through elevating heme-oxygenase 1 expression

Environmental Pollution ◽

10.1016/j.envpol.2021.117213 ◽

2021 ◽

Vol 284 ◽

pp. 117213

Author(s):

Lin Xu ◽

Qianwen Zhao ◽

Daochuan Li ◽

Jiao Luo ◽

Wanli Ma ◽

...

Keyword(s):

Epithelial Cells ◽

Heme Oxygenase ◽

Bronchial Epithelial Cells ◽

Heme Oxygenase 1 ◽

Human Bronchial Epithelial Cells ◽

Bronchial Epithelial ◽

Induced Apoptosis

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Early heme oxygenase 1 induction delays tumour initiation and enhances DNA damage repair in liver macrophages of Mdr2−/− mice

Scientific Reports ◽

10.1038/s41598-018-33233-0 ◽

2018 ◽

Vol 8 (1) ◽

Cited By ~ 1

Author(s):

Roja Barikbin ◽

Laura Berkhout ◽

Julia Bolik ◽

Dirk Schmidt-Arras ◽

Thomas Ernst ◽

...

Keyword(s):

Dna Damage ◽

Heme Oxygenase ◽

Dna Damage Repair ◽

Heme Oxygenase 1 ◽

Liver Macrophages ◽

Damage Repair ◽

Tumour Initiation

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Mechanisms underlying induction of heme oxygenase-1 by nitric oxide in renal tubular epithelial cells

AJP Renal Physiology ◽

10.1152/ajprenal.2000.279.4.f728 ◽

2000 ◽

Vol 279 (4) ◽

pp. F728-F735 ◽

Cited By ~ 27

Author(s):

Mingyu Liang ◽

Anthony J. Croatt ◽

Karl A. Nath

Keyword(s):

Nitric Oxide ◽

Epithelial Cells ◽

Sodium Nitroprusside ◽

Nitric Oxide Donor ◽

Heme Oxygenase 1 ◽

Tubular Epithelial Cells ◽

Cytotoxic Effects ◽

Proximal Tubular Epithelial Cells ◽

Proximal Tubular ◽

Renal Proximal Tubular

We examined whether nitric oxide-generating agents influence expression of heme oxygenase-1 (HO-1) in renal proximal tubular epithelial cells, LLC-PK1 cells, and the mechanisms underlying any such effects. In sublytic amounts, the nitric oxide donor sodium nitroprusside induced HO-1 mRNA and protein and HO activity in a dose-dependent and time-dependent fashion; this induction was specific for nitric oxide since the nitric oxide scavenger carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide significantly reduced such induction. The induction of HO activity by sodium nitroprusside, or by another nitric oxide donor, spermine NONOate, was markedly reduced by the iron chelator deferoxamine. Two different thiol-containing agents, N-acetylcysteine and dithiothreitol, blunted such induction of HO by nitric oxide. Downstream products of nitric oxide, such as peroxynitrite or cGMP, were not involved in inducing HO. In higher concentrations (millimolar amounts), sodium nitroprusside induced appreciable cytotoxicity as assessed by lactate dehydrogenase (LDH) release and lipid peroxidation, and both of these effects were markedly reduced by deferoxamine. Inhibition of HO did not affect the cytotoxic effects (measured by LDH release) of sodium nitroprusside. We thus provide the novel description of the induction of HO-1 in renal proximal tubular epithelial cells exposed to nitric oxide donors and provide the first demonstration in kidney-derived cells for the involvement of a redox-based mechanism in such expression. We also demonstrate that, in LLC-PK1 cells exposed to nitric oxide donors, chelatable iron is involved in eliciting the HO-1 response observed at lower concentrations of these donors, and in mediating the cytotoxic effects of these donors when present in higher concentrations.

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Molecular Mechanisms of Zinc Oxide Nanoparticle-Induced Genotoxicity

Materials ◽

10.3390/ma10121427 ◽

2017 ◽

Vol 10 (12) ◽

pp. 1427 ◽

Cited By ~ 25

Author(s):

Agmal Scherzad ◽

Till Meyer ◽

Norbert Kleinsasser ◽

Stephan Hackenberg

Keyword(s):

Dna Damage ◽

Zinc Oxide ◽

Mammalian Cells ◽

Oxidative Dna Damage ◽

Molecular Mechanisms ◽

Consumer Products ◽

Zno Nps ◽

Cytotoxic Effects

Background: Zinc oxide nanoparticles (ZnO NPs) are among the most frequently applied nanomaterials in consumer products. Evidence exists regarding the cytotoxic effects of ZnO NPs in mammalian cells; however, knowledge about the potential genotoxicity of ZnO NPs is rare, and results presented in the current literature are inconsistent. Objectives: The aim of this review is to summarize the existing data regarding the DNA damage that ZnO NPs induce, and focus on the possible molecular mechanisms underlying genotoxic events. Methods: Electronic literature databases were systematically searched for studies that report on the genotoxicity of ZnO NPs. Results: Several methods and different endpoints demonstrate the genotoxic potential of ZnO NPs. Most publications describe in vitro assessments of the oxidative DNA damage triggered by dissoluted Zn2+ ions. Most genotoxicological investigations of ZnO NPs address acute exposure situations. Conclusion: Existing evidence indicates that ZnO NPs possibly have the potential to damage DNA. However, there is a lack of long-term exposure experiments that clarify the intracellular bioaccumulation of ZnO NPs and the possible mechanisms of DNA repair and cell survival.

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Healthcare Workers Occupationally Exposed to Ionizing Radiation Exhibit Altered Levels of Inflammatory Cytokines and Redox Parameters

Antioxidants ◽

10.3390/antiox8010012 ◽

2019 ◽

Vol 8 (1) ◽

pp. 12 ◽

Cited By ~ 6

Author(s):

Iman M. Ahmad ◽

Maher Y. Abdalla ◽

Tiffany A. Moore ◽

Lisa Bartenhagen ◽

Adam J. Case ◽

...

Keyword(s):

Dna Damage ◽

Ionizing Radiation ◽

Healthcare Workers ◽

Immune Modulation ◽

Oxidative Dna Damage ◽

Underlying Mechanism ◽

Increased Risk ◽

Exposed Workers ◽

Immune Alterations ◽

Occupationally Exposed

Studies have shown an increased risk for a variety of cancers, specifically brain cancer, in healthcare workers occupationally exposed to ionizing radiation. Although the mechanisms mediating these phenomena are not fully understood, ionizing radiation-mediated elevated levels of reactive oxygen species (ROS), oxidative DNA damage, and immune modulation are likely involved. A group of 20 radiation exposed workers and 40 sex- and age-matched non-exposed control subjects were recruited for the study. We measured superoxide (O2•−) levels in whole blood of healthcare workers and all other measurements of cytokines, oxidative DNA damage, extracellular superoxide dismutase (EcSOD) activity and reduced/oxidized glutathione ratio (GSH/GSSG) in plasma. Levels of O2•− were significantly higher in radiation exposed workers compared to control. Similarly, a significant increase in the levels of interleukin (IL)-6, IL-1α and macrophage inflammatory protein (MIP)-1α in radiation exposed workers compared to control was observed, while there was no significance difference in the other 27 screened cytokines. A significant positive correlation was found between MIP-1α and O2•− levels with no correlation in either IL-6 or IL-1α. Further, a dose-dependent relationship with significant O2•− production and immune alterations in radiation exposed workers was demonstrated. There was no statistical difference between the groups in terms of oxidative DNA damage, GSH/GSSG levels, or EcSOD activity. Although the biologic significance of cytokines alterations in radiation exposed workers is unclear, further studies are needed for determining the underlying mechanism of their elevation.

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Mutations in CREBBP and EP300 genes affect DNA repair of oxidative damage in Rubinstein-Taybi syndrome cells

Carcinogenesis ◽

10.1093/carcin/bgz149 ◽

2019 ◽

Vol 41 (3) ◽

pp. 257-266

Author(s):

Ilaria Dutto ◽

Claudia Scalera ◽

Micol Tillhon ◽

Giulio Ticli ◽

Gianluca Passaniti ◽

...

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Genome Stability ◽

Oxidative Dna Damage ◽

Excision Repair ◽

Control Cell ◽

Nuclear Antigen ◽

Autosomal Dominant Disorder ◽

Cell Extracts ◽

Increased Risk

Abstract Rubinstein-Taybi syndrome (RSTS) is an autosomal-dominant disorder characterized by intellectual disability, skeletal abnormalities, growth deficiency and an increased risk of tumors. RSTS is predominantly caused by mutations in CREBBP or EP300 genes encoding for CBP and p300 proteins, two lysine acetyl-transferases (KAT) playing a key role in transcription, cell proliferation and DNA repair. However, the efficiency of these processes in RSTS cells is still largely unknown. Here, we have investigated whether pathways involved in the maintenance of genome stability are affected in lymphoblastoid cell lines (LCLs) obtained from RSTS patients with mutations in CREBBP or in EP300 genes. We report that RSTS LCLs with mutations affecting CBP or p300 protein levels or KAT activity, are more sensitive to oxidative DNA damage and exhibit defective base excision repair (BER). We have found reduced OGG1 DNA glycosylase activity in RSTS compared to control cell extracts, and concomitant lower OGG1 acetylation levels, thereby impairing the initiation of the BER process. In addition, we report reduced acetylation of other BER factors, such as DNA polymerase β and Proliferating Cell Nuclear Antigen (PCNA), together with acetylation of histone H3. We also show that complementation of CBP or p300 partially reversed RSTS cell sensitivity to DNA damage. These results disclose a mechanism of defective DNA repair as a source of genome instability in RSTS cells.

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Cytotoxic Effects of Air Freshener Biocides in Lung Epithelial Cells

Natural Product Communications ◽

10.1177/1934578x1300800929 ◽

2013 ◽

Vol 8 (9) ◽

pp. 1934578X1300800

Author(s):

Jung-Taek Kwon ◽

Mimi Lee ◽

Gun-Baek Seo ◽

Hyun-Mi Kim ◽

Ilseob Shim ◽

...

Keyword(s):

Dna Damage ◽

Epithelial Cells ◽

Cell Viability ◽

Lung Epithelial Cells ◽

Ros Generation ◽

Dependent Manner ◽

Cytotoxic Effects ◽

Lung Epithelial ◽

Dose Dependent ◽

A549 Lung

This study evaluated the cytotoxicity of mixtures of citral (CTR) and either benzisothiazolinone (BIT, Mix-CTR-BIT) or triclosan (TCS, Mix-CTR-TCS) in human A549 lung epithelial cells. We investigated the effects of various mix ratios of these common air freshener ingredients on cell viability, cell proliferation, reactive oxygen species (ROS) generation, and DNA damage. Mix-CTR-BIT and Mix-CTR-TCS significantly decreased the viability of lung epithelial cells and inhibited cell growth in a dose-dependent manner. In addition, both mixtures increased ROS generation, compared to that observed in control cells. In particular, cell viability, growth, and morphology were affected upon increase in the proportion of BIT or TCS in the mixture. However, comet analysis showed that treatment of cells with Mix-CTR-BIT or Mix-CTR-TCS did not increase DNA damage. Taken together, these data suggested that increasing the content of biocides in air fresheners might induce cytotoxicity, and that screening these compounds using lung epithelial cells may contribute to hazard assessment.

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