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Role of Heme Oxygenase in Gastrointestinal Epithelial Cells. Antioxidants (Basel) 2022; 11:antiox11071323. [PMID: 35883814 PMCID: PMC9311893 DOI: 10.3390/antiox11071323] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 02/04/2023] Open
Abstract
The gastrointestinal tract is a unique organ containing both vascular and luminal routes lined by epithelial cells forming the mucosa, which play an important role in the entry of nutrients and act as a selective barrier, excluding potentially harmful agents. Mucosal surfaces establish a selective barrier between hostile external environments and the internal milieu. Heme is a major nutritional source of iron and is a pro-oxidant that causes oxidative stress. Heme oxygenases (HOs) catalyze the rate-limiting step in heme degradation, resulting in the formation of iron, carbon monoxide, and biliverdin, which are subsequently converted to bilirubin by biliverdin reductase. In gastrointestinal pathogenesis, HO-1, an inducible isoform of HO, is markedly induced in epithelial cells and plays an important role in protecting mucosal cells. Recent studies have focused on the biological effects of the products of this enzymatic reaction, which have antioxidant, anti-inflammatory, and cytoprotective functions. In this review, the essential roles of HO in the gastrointestinal tract are summarized, focusing on nutrient absorption, protection against cellular stresses, and the maintenance and regulation of tight junction proteins, emphasizing the potential therapeutic implications. The biochemical basis of the potential therapeutic implications of glutamine for HO-1 induction in gastrointestinal injury is also discussed.
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2
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Hemin Prevents Increased Glycolysis in Macrophages upon Activation: Protection by Microbiota-Derived Metabolites of Polyphenols. Antioxidants (Basel) 2020; 9:antiox9111109. [PMID: 33187129 PMCID: PMC7696608 DOI: 10.3390/antiox9111109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 11/06/2020] [Accepted: 11/08/2020] [Indexed: 12/24/2022] Open
Abstract
Meat consumption plays a critical role in the development of several types of cancer. Hemin, a metabolite of myoglobin produced after meat intake, has been demonstrated to be involved in the cancer initiation phase. Macrophages are key components of the innate immunity, which, upon activation, can prevent cancer development by eliminating neoplastic cells. Metabolic reprogramming, characterized by high glycolysis and low oxidative phosphorylation, is critical for macrophage activation. 3,4-dihydroxyphenylacetic acid (3,4DHPAA) and 4-hydroxyphenylacetic acid (4HPAA), both microbiota-derived metabolites of flavonoids, have not been extensively studied although they exert antioxidant properties. The aim of this study was to determine the effect of hemin on the anticancer properties of macrophages and the role of 3,4DHPAA and 4HPAA in metabolic reprogramming and activation of macrophages leading to the elimination of cancer cells. The results showed that hemin inhibited glycolysis, glycolytic, and pentose phosphate pathway (PPP) enzyme activities and hypoxia-inducible factor-1 alpha (HIF-1α) stabilization, which interferes with macrophage activation (evidenced by decreased interferon-γ-inducible protein 10 (IP-10) release) and their ability to eliminate cancer cells (via cytotoxic mediators and phagocytosis). Hemin also reduced the mitochondrial membrane potential (MMP) and mitochondrial mass in macrophages. 3,4DHPAA and 4HPAA, by stimulating glycolysis and PPP, prevented the impairment of the macrophage anticancer activity induced by hemin. In conclusion, 3,4HPAA and 4HPAA administration could represent a promising strategy for preventing the reduction of macrophage activation induced by hemin.
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3
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Ma Y, Okazaki Y, Glass J. A fluorescent metal-sensor study provides evidence for iron transport by transcytosis in the intestinal epithelial cells. J Clin Biochem Nutr 2018; 62:49-55. [PMID: 29362518 PMCID: PMC5773836 DOI: 10.3164/jcbn.17-74] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 08/27/2017] [Indexed: 12/17/2022] Open
Abstract
Iron transport across the intestinal epithelium is facilitated by the divalent metal transporter 1 (DMT1) on the brush border membrane (BBM). The fluorescent metal sensor calcein, which is hydrophilic, membrane-impermeable and quenched by chelation with iron, was used to test our hypothesis that intestinal iron absorption is through the endocytic processes and is involved in a pathway where BBM-derived vesicles fuse with basolateral membrane (BLM)-derived vesicles. To monitor the flux of iron via transcytosis, Caco-2 cells were employed as a polarized cell layer in Transwell chambers. When calcein was added to the basal chamber along with apo-transferrin (apo-Tf), calcein rapidly underwent endocytosis and co-localized with apo-Tf. Calcein was quenched by adding an iron-ascorbate complex and then restored by adding 2,2'-dipyridyl into the apical chamber. These results were confirmed by live-cell imaging. When hemin from the apical surface and calcein from the basal chamber were added to the Caco-2 cells, internalization of DMT1 and quenching of calcein were not observed until 2 h later. These results indicated that absorbed hemin required processing before hemin-derived iron was available to BLM-derived vesicles. These studies suggest that iron is transported in Caco-2 cells by transcytosis with apical-derived vesicles that are fused to BLM-derived vesicles.
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Affiliation(s)
- Yuxiang Ma
- Feist-Weiller Cancer Center and the Department of Medicine, Louisiana State University Health Sciences Center-Shreveport, 1501 Kings Highway, Shreveport, LA 71130, USA
| | - Yasumasa Okazaki
- Feist-Weiller Cancer Center and the Department of Medicine, Louisiana State University Health Sciences Center-Shreveport, 1501 Kings Highway, Shreveport, LA 71130, USA
| | - Jonathan Glass
- Feist-Weiller Cancer Center and the Department of Medicine, Louisiana State University Health Sciences Center-Shreveport, 1501 Kings Highway, Shreveport, LA 71130, USA
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4
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Abstract
Heme is universally recognized as an essential and ubiquitous prosthetic group that enables proteins to carry out a diverse array of functions. All heme-dependent processes, from protein hemylation to heme signaling, require the dynamic and rapid mobilization of heme to hemoproteins present in virtually every subcellular compartment. The cytotoxicity and hydrophobicity of heme necessitates that heme mobilization is carefully controlled at the cellular and systemic level. However, the molecules and mechanisms that mediate heme homeostasis are poorly understood. In this Account, we provide a heuristic paradigm with which to conceptualize heme trafficking and highlight the most recent developments in the mechanisms underlying heme trafficking. As an iron-containing tetrapyrrole, heme exhibits properties of both transition metals and lipids. Accordingly, we propose its transport and trafficking will reflect principles gleaned from the trafficking of both metals and lipids. Using this conceptual framework, we follow the flow of heme from the final step of heme synthesis in the mitochondria to hemoproteins present in various subcellular organelles. Further, given that many cells and animals that cannot make heme can assimilate it intact from nutritional sources, we propose that intercellular heme trafficking pathways must exist. This necessitates that heme be able to be imported and exported from cells, escorted between cells and organs, and regulated at the organismal level via a coordinated systemic process. In this Account, we highlight recently discovered heme transport and trafficking factors and provide the biochemical foundation for the cell and systems biology of heme. Altogether, we seek to reconceptualize heme from an exchange inert cofactor buried in hemoprotein active sites to an exchange labile and mobile metallonutrient.
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Affiliation(s)
- Amit R. Reddi
- School of Chemistry and Biochemistry and Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Iqbal Hamza
- Department of Animal and Avian Sciences and Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20740, United States
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5
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The effect of proteins from animal source foods on heme iron bioavailability in humans. Food Chem 2016; 196:733-8. [DOI: 10.1016/j.foodchem.2015.10.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 08/26/2015] [Accepted: 10/04/2015] [Indexed: 02/07/2023]
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6
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Akagi R, Akagi M, Hatori Y, Inouye S. Prevention of Barrier Disruption by Heme Oxygenase-1 in Intestinal Bleeding Model. Biol Pharm Bull 2016; 39:1007-12. [DOI: 10.1248/bpb.b15-01028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Reiko Akagi
- Department of Pharmacy, Faculty of Pharmacy, Yasuda Women’s University
| | - Masaaki Akagi
- Department of Pharmacology, Faculty of Pharmaceutical Science, Tokushima Bunri University
| | - Yuta Hatori
- Department of Pharmacy, Faculty of Pharmacy, Yasuda Women’s University
| | - Sachiye Inouye
- Department of Pharmacy, Faculty of Pharmacy, Yasuda Women’s University
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7
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Chen SW, Ma YY, Zhu J, Zuo S, Zhang JL, Chen ZY, Chen GW, Wang X, Pan YS, Liu YC, Wang PY. Protective effect of 1,25-dihydroxyvitamin D3 on ethanol-induced intestinal barrier injury both in vitro and in vivo. Toxicol Lett 2015; 237:79-88. [PMID: 26068064 DOI: 10.1016/j.toxlet.2015.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 06/03/2015] [Accepted: 06/05/2015] [Indexed: 02/08/2023]
Abstract
Studies have suggested the role of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in protecting intestinal barrier function from injuries induced by multiple reagents. Vitamin D deficiency was reported to be associated with poor prognosis in patients with alcoholic liver disease (ALD). This study is designed to investigate the effect of 1,25(OH)2D3 on ethanol-induced intestinal barrier dysfunction and the underlying mechanisms utilizing Caco-2 cell monolayers and a mouse model with acute ethanol injury. In Caco-2 monolayers, ethanol significantly increased monolayer permeability, disrupted TJ distribution, increased phosphorylation level of MLC, and induced generation of ROS compared with controls. However, pre-treatment with 1,25(OH)2D3 greatly ameliorated the ethanol-induced barrier dysfunction, TJ disruption, phosphorylation level of MLC, and generation of ROS compared with ethanol-exposed monolayers. Mice fed with vitamin d-sufficient diet had a higher plasma level of 25(OH)D3 and were more resistant to ethanol-induced acute intestinal barrier injury compared with the vitamin d-deficient group. These results suggest that the suppression of generation of ROS and increased phosphorylation level of MLC might be one of the mechanisms underlying the protective effect of 1,25(OH)2D3 on ethanol-induced intestinal barrier injury and provide evidence for the application of vitamin D as therapeutic factors against ethanol-induced gut leakiness.
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Affiliation(s)
- Shan-Wen Chen
- Division of General Surgery, Peking University First Hospital, Peking University, 8 Xi ShiKu Street, Beijing 100034, PR China
| | - Yuan-Yuan Ma
- Animal Experiment Center, Peking University First Hospital, Peking University, 8 Xi ShiKu Street, Beijing 100034, PR China
| | - Jing Zhu
- Division of General Surgery, Peking University First Hospital, Peking University, 8 Xi ShiKu Street, Beijing 100034, PR China
| | - Shuai Zuo
- Division of General Surgery, Peking University First Hospital, Peking University, 8 Xi ShiKu Street, Beijing 100034, PR China
| | - Jun-Ling Zhang
- Division of General Surgery, Peking University First Hospital, Peking University, 8 Xi ShiKu Street, Beijing 100034, PR China
| | - Zi-Yi Chen
- Division of General Surgery, Peking University First Hospital, Peking University, 8 Xi ShiKu Street, Beijing 100034, PR China
| | - Guo-Wei Chen
- Division of General Surgery, Peking University First Hospital, Peking University, 8 Xi ShiKu Street, Beijing 100034, PR China
| | - Xin Wang
- Division of General Surgery, Peking University First Hospital, Peking University, 8 Xi ShiKu Street, Beijing 100034, PR China
| | - Yi-Sheng Pan
- Division of General Surgery, Peking University First Hospital, Peking University, 8 Xi ShiKu Street, Beijing 100034, PR China
| | - Yu-Cun Liu
- Division of General Surgery, Peking University First Hospital, Peking University, 8 Xi ShiKu Street, Beijing 100034, PR China
| | - Peng-Yuan Wang
- Division of General Surgery, Peking University First Hospital, Peking University, 8 Xi ShiKu Street, Beijing 100034, PR China.
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Elamin E, Masclee A, Troost F, Dekker J, Jonkers D. Cytotoxicity and metabolic stress induced by acetaldehyde in human intestinal LS174T goblet-like cells. Am J Physiol Gastrointest Liver Physiol 2014; 307:G286-94. [PMID: 24904079 DOI: 10.1152/ajpgi.00103.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
There is compelling evidence indicating that ethanol and its oxidative metabolite acetaldehyde can disrupt intestinal barrier function. Apart from the tight junctions, mucins secreted by goblet cells provide an effective barrier. Ethanol has been shown to induce goblet cell injury associated with alterations in mucin glycosylation. However, effects of its most injurious metabolite acetaldehyde remain largely unknown. This study aimed to assess short-term effects of acetaldehyde (0, 25, 50, 75, 100 μM) on functional characteristics of intestinal goblet-like cells (LS174T). Oxidative stress, mitochondrial function, ATP, and intramitochondrial calcium (Ca(2+)) were assessed by dichlorofluorescein, methyltetrazolium, and bioluminescence, MitoTracker green and rhod-2 double-labeling. Membrane integrity and apoptosis were evaluated by measuring lactate dehydrogenase (LDH), caspase 3/7, and cleavage of cytokeratin 18 (CK18). Expression of mucin 2 (MUC2) was determined by cell-based ELISA. Acetaldehyde significantly increased reactive oxygen species generation and decreased mitochondrial function compared with negative controls (P < 0.05). In addition, acetaldehyde dose-dependently decreased ATP levels and induced intramitochondrial Ca(2+) accumulation compared with negative controls (P < 0.05). Furthermore, acetaldehyde induced LDH release and increased caspase3/7 activity and percentage of cells expressing cleaved CK18 and increased MUC2 protein expression compared with negative controls (P < 0.0001). ATP depletion and LDH release could be largely prevented by the antioxidant N-acetylcysteine, suggesting a pivotal role for oxidative stress. Our data demonstrate that acetaldehyde has distinct oxidant-dependent metabolic and cytotoxic effects on LS174T cells that can lead to induction of cellular apoptosis. These effects may contribute to acetaldehyde-induced intestinal barrier dysfunction and subsequently to liver injury.
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Affiliation(s)
- Elhaseen Elamin
- Top Institute Food and Nutrition, Wageningen, the Netherlands; Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; School for Nutrition, Toxicology and Metabolism of Maastricht University Medical Center, Maastricht, the Netherlands; and
| | - Ad Masclee
- Top Institute Food and Nutrition, Wageningen, the Netherlands; Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; School for Nutrition, Toxicology and Metabolism of Maastricht University Medical Center, Maastricht, the Netherlands; and
| | - Freddy Troost
- Top Institute Food and Nutrition, Wageningen, the Netherlands; Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; School for Nutrition, Toxicology and Metabolism of Maastricht University Medical Center, Maastricht, the Netherlands; and
| | - Jan Dekker
- Top Institute Food and Nutrition, Wageningen, the Netherlands; Department of Animal Sciences, Wageningen UR, Wageningen, the Netherlands
| | - Daisy Jonkers
- Top Institute Food and Nutrition, Wageningen, the Netherlands; Division of Gastroenterology-Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; School for Nutrition, Toxicology and Metabolism of Maastricht University Medical Center, Maastricht, the Netherlands; and
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9
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Korolnek T, Hamza I. Like iron in the blood of the people: the requirement for heme trafficking in iron metabolism. Front Pharmacol 2014; 5:126. [PMID: 24926267 PMCID: PMC4045156 DOI: 10.3389/fphar.2014.00126] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 05/12/2014] [Indexed: 12/17/2022] Open
Abstract
Heme is an iron-containing porphyrin ring that serves as a prosthetic group in proteins that function in diverse metabolic pathways. Heme is also a major source of bioavailable iron in the human diet. While the synthesis of heme has been well-characterized, the pathways for heme trafficking remain poorly understood. It is likely that heme transport across membranes is highly regulated, as free heme is toxic to cells. This review outlines the requirement for heme delivery to various subcellular compartments as well as possible mechanisms for the mobilization of heme to these compartments. We also discuss how these trafficking pathways might function during physiological events involving inter- and intra-cellular mobilization of heme, including erythropoiesis, erythrophagocytosis, heme absorption in the gut, as well as heme transport pathways supporting embryonic development. Lastly, we aim to question the current dogma that heme, in toto, is not mobilized from one cell or tissue to another, outlining the evidence for these pathways and drawing parallels to other well-accepted paradigms for copper, iron, and cholesterol homeostasis.
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Affiliation(s)
- Tamara Korolnek
- Department of Animal & Avian Sciences, University of Maryland, College Park MD, USA ; Department of Cell Biology & Molecular Genetics, University of Maryland, College Park MD, USA
| | - Iqbal Hamza
- Department of Animal & Avian Sciences, University of Maryland, College Park MD, USA ; Department of Cell Biology & Molecular Genetics, University of Maryland, College Park MD, USA
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10
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Sahoo S, Aurich MK, Jonsson JJ, Thiele I. Membrane transporters in a human genome-scale metabolic knowledgebase and their implications for disease. Front Physiol 2014; 5:91. [PMID: 24653705 PMCID: PMC3949408 DOI: 10.3389/fphys.2014.00091] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 02/17/2014] [Indexed: 01/18/2023] Open
Abstract
Membrane transporters enable efficient cellular metabolism, aid in nutrient sensing, and have been associated with various diseases, such as obesity and cancer. Genome-scale metabolic network reconstructions capture genomic, physiological, and biochemical knowledge of a target organism, along with a detailed representation of the cellular metabolite transport mechanisms. Since the first reconstruction of human metabolism, Recon 1, published in 2007, progress has been made in the field of metabolite transport. Recently, we published an updated reconstruction, Recon 2, which significantly improved the metabolic coverage and functionality. Human metabolic reconstructions have been used to investigate the role of metabolism in disease and to predict biomarkers and drug targets. Given the importance of cellular transport systems in understanding human metabolism in health and disease, we analyzed the coverage of transport systems for various metabolite classes in Recon 2. We will review the current knowledge on transporters (i.e., their preferred substrates, transport mechanisms, metabolic relevance, and disease association for each metabolite class). We will assess missing coverage and propose modifications and additions through a transport module that is functional when combined with Recon 2. This information will be valuable for further refinements. These data will also provide starting points for further experiments by highlighting areas of incomplete knowledge. This review represents the first comprehensive overview of the transporters involved in central metabolism and their transport mechanisms, thus serving as a compendium of metabolite transporters specific for human metabolic reconstructions.
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Affiliation(s)
- Swagatika Sahoo
- Center for Systems Biology, University of Iceland Reykjavik, Iceland ; Molecular Systems Physiology Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg Belval, Luxembourg
| | - Maike K Aurich
- Center for Systems Biology, University of Iceland Reykjavik, Iceland ; Molecular Systems Physiology Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg Belval, Luxembourg
| | - Jon J Jonsson
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Iceland Reykjavik, Iceland ; Department of Genetics and Molecular Medicine, Landspitali, National University Hospital of Iceland Reykjavik, Iceland
| | - Ines Thiele
- Center for Systems Biology, University of Iceland Reykjavik, Iceland ; Molecular Systems Physiology Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg Belval, Luxembourg
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11
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Elamin EE, Masclee AA, Dekker J, Pieters HJ, Jonkers DM. Short-chain fatty acids activate AMP-activated protein kinase and ameliorate ethanol-induced intestinal barrier dysfunction in Caco-2 cell monolayers. J Nutr 2013; 143:1872-81. [PMID: 24132573 DOI: 10.3945/jn.113.179549] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Short-chain fatty acids (SCFAs) have been shown to promote intestinal barrier function, but their protective effects against ethanol-induced intestinal injury and underlying mechanisms remain essentially unknown. The aim of the study was to analyze the influence of SCFAs on ethanol-induced barrier dysfunction and to examine the role of AMP-activated protein kinase (AMPK) as a possible mechanism using Caco-2 monolayers. The monolayers were treated apically with butyrate (2, 10, or 20 mmol/L), propionate (4, 20, or 40 mmol/L), or acetate (8, 40, or 80 mmol/L) for 1 h before ethanol (40 mmol/L) for 3 h. Barrier function was analyzed by measurement of transepithelial resistance and permeation of fluorescein isothiocyanate-labeled dextran. Distribution of the tight junction (TJ) proteins zona occludens-1, occludin, and filamentous-actin (F-actin) was examined by immunofluorescence. Metabolic stress was determined by measuring oxidative stress, mitochondrial function, and ATP using dichlorofluorescein diacetate, dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide, and bioluminescence assay, respectively. AMPK was knocked down by small interfering RNA (siRNA), and its activity was assessed by a cell-based ELISA. Exposure to ethanol significantly impaired barrier function compared with controls (P < 0.0001), disrupted TJ and F-actin cytoskeleton integrity, and induced metabolic stress. However, pretreatment with 2 mmol/L butyrate, 4 mmol/L propionate, and 8 mmol/L acetate significantly alleviated the ethanol-induced barrier dysfunction, TJ and F-actin disruption, and metabolic stress compared with ethanol-exposed monolayers (P < 0.0001). The promoting effects on barrier function were abolished by inhibiting AMPK using either compound C or siRNA. These observations indicate that SCFAs exhibit protective effects against ethanol-induced barrier disruption via AMPK activation, suggesting a potential for SCFAs as prophylactic and/or therapeutic factors against ethanol-induced gut leakiness.
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12
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Yi G, Haug A, Nyquist NF, Egelandsdal B. Hydroperoxide formation in different lean meats. Food Chem 2013; 141:2656-65. [PMID: 23871008 DOI: 10.1016/j.foodchem.2013.05.041] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 04/04/2013] [Accepted: 05/13/2013] [Indexed: 12/01/2022]
Abstract
Peroxide is one of the compounds that are indicated to be toxic in the human digestion system. Lean fresh meat samples were collected from beef, lamb, pork and chicken to investigate their hydroperoxide formation potential. Total peroxides of fresh comminuted raw meat were determined by analysing protein-bound peroxides and hydroperoxide compounds in water-methanol and chloroform extracted phases. The amount of total peroxides was ranked as: beef>pork>lamb>chicken. Hydroperoxide formation was examined at different pH values and at different incubation times, using beef and chicken samples. All peroxides were transient, with a maximum value after 2-4 h of incubation at 37 °C. When pH fell from 7 to 1.5, the different peroxides fell by 10-20%. Non-polar peroxide formation could largely (70%) be described by variation in fatty acid composition and hemin content of the meat, while protein-bound peroxide variation was less explained by these variables. Liposome addition increased (40%) the amount of protein-bound peroxides.
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Affiliation(s)
- Gu Yi
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Aas, Norway.
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13
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Larson DS, Coyne DW. Understanding and exploiting hepcidin as an indicator of anemia due to chronic kidney disease. Kidney Res Clin Pract 2013; 32:11-5. [PMID: 26894030 PMCID: PMC4716122 DOI: 10.1016/j.krcp.2013.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 12/24/2012] [Accepted: 12/28/2012] [Indexed: 12/21/2022] Open
Abstract
Hepcidin, produced by the liver, is the master regulator of iron balance. Serum hepcidin is increased by high iron stores, blocks intestinal iron absorption, and impairs storage iron release. Conversely, iron deficiency lowers hepcidin levels and enhances intestinal iron absorption and the release of storage iron. As with ferritin, hepcidin is an acute phase reactant. Consequently, inflammation increases hepcidin and leads to impaired iron absorption, lowers serum iron and transferrin saturation, and contributes to the anemia of chronic kidney disease (CKD). We review the physiology of iron absorption, its relationship to hepcidin and the transmembrane iron transporter ferroportin, the role of hepcidin in CKD related anemia, and the possible diagnostic implications and limitations of using hepcidin as a marker of iron status.
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Affiliation(s)
- Derek S Larson
- Renal Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Daniel W Coyne
- Renal Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
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14
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Cediel G, Olivares M, Gaitán D, Flores S, Brito A, Pizarro F. Effect of trypsin and mucin on heme iron bioavailability in humans. Biol Trace Elem Res 2012; 150:37-41. [PMID: 23011661 DOI: 10.1007/s12011-012-9483-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 07/27/2012] [Indexed: 10/28/2022]
Abstract
UNLABELLED In the human gastrointestinal tract, trypsin and mucin may affect the absorption of heme iron. However, these interactions have not been well-established. We determined the effect of trypsin and mucin on heme iron absorption in humans. DESIGN Twenty-eight apparently healthy females participated in two studies (14 per study). Study A evaluated the effect of trypsin on iron bioavailability. Subjects ingested 100 mg trypsin and 1.7 g mucin on 5 mg heme iron bioavailability on days 1, 2, 14, and 15, respectively. In study B, which assessed the effect of mucin on heme iron bioavailability, the subjects ingested hemin, hemin plus mucin, hemoglobin (Hb), and Hb plus mucin, on days 1, 2, 14, and 15, respectively. RESULTS In study A, the geometric means ± 1 SD of heme iron absorption were 5.1 % (3.1-8.3), 2.9 % (1.6-5.1), 7.3 % (4.1-13.1), and 6 % (2.7-13) for hemin, hemin plus trypsin, Hb plus trypsin, and Hb plus mucin plus trypsin, respectively. In study B, the geometric means ± 1 SD of heme iron absorption were 16.4 % (10.5-25.7), 13.1 % (9.0-18.9), 13.7 % (9.0-20.7), and 11.8 % (7.6-18.3) for hemin, hemin plus mucin, Hb, and Hb plus mucin, respectively. The ratio increased when Hb plus trypsin was ingested and decreased when hemin plus trypsin was ingested. There were no differences in other ratios with respect to the ratio on day 1 (P < 0.05). CONCLUSION Trypsin is the only human gastrointestinal protein that evaluated the affects of heme iron absorption. However, this effect depends on how heme iron is ingested.
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Affiliation(s)
- Gustavo Cediel
- Micronutrients Laboratory, Institute of Nutrition and Food Technology (INTA), University of Chile, Avda El Líbano 5524, Casilla 13811, Santiago, Chile
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15
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Abstract
PURPOSE OF REVIEW Heme biosynthesis requires a series of enzymatic reactions that take place in the cytosol and the mitochondria as well as the proper intercellular and intracellular trafficking of iron. Heme can also be acquired by intestinal absorption and intercellular transport. The purpose of this review is to highlight recent work on heme and iron transport with an emphasis on their relevance in erythropoiesis. RECENT FINDINGS Whereas the enzymes responsible for heme biosynthesis have been identified, transport mechanisms for iron, heme, or heme synthesis intermediates are only emerging. Recent studies have shed light on how these molecules are transported among various cellular compartments, as well as tissues. Much of this progress can be attributed to the use of model organisms such as S. cerevisiae, C. elegans, D. rerio, and M. musculus. Genetic studies in these models have led to the identification of several new genes involved in heme metabolism. Although our understanding has greatly improved, it is highly likely that other regulators exist and additional work is required to characterize the pathways by which heme and iron are transported within the erythron. SUMMARY The identification of heme and iron transport mechanisms will improve our understanding of blood development and provide new insight into human blood disorders.
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Le Blanc S, Garrick MD, Arredondo M. Heme carrier protein 1 transports heme and is involved in heme-Fe metabolism. Am J Physiol Cell Physiol 2012; 302:C1780-5. [DOI: 10.1152/ajpcell.00080.2012] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heme-Fe is an important source of dietary iron in humans; however, the mechanism for heme-Fe uptake by enterocytes is poorly understood. Heme carrier protein 1 (HCP1) was originally identified as mediating heme-Fe transport although it later emerged that it was a folate transporter. We asked what happened to heme-Fe and folate uptake and the relative abundance of hcp1 and ho1 mRNA in Caco-2 cells after knockdown by transfection with HCP1-directed short hairpin (sh)RNA. Control Caco-2 cells were cultured in bicameral chambers with 0–80 μM heme-Fe for selected times. Intracellular Fe and heme concentration increased in Caco-2 cells reflecting higher external heme-Fe concentrations. Maximum Fe, heme, and heme oxygenase 1 (HO1) expression and activity were observed between 12 and 24 h of incubation. Quantitative RT-PCR for hcp1 revealed that its mRNA decreased at 20 μM heme-Fe while ho1 mRNA and activity increased. When shRNA knocked down hcp1 mRNA, heme-55Fe uptake and [3H]folate transport mirrored the mRNA decrease, ho1 mRNA increased, and flvcr mRNA was unchanged. These data argue that HCP1 is involved in low-affinity heme-Fe uptake not just in folate transport.
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Affiliation(s)
- Solange Le Blanc
- Micronutrient Laboratory, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile; and
| | - Michael D. Garrick
- Department of Biochemistry, State University of New York, Buffalo, New York
| | - Miguel Arredondo
- Micronutrient Laboratory, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile; and
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17
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Jahn MR, Shukoor I, Tremel W, Wolfrum U, Kolb U, Nawroth T, Langguth P. Hemin-coupled iron(III)-hydroxide nanoparticles show increased uptake in Caco-2 cells. J Pharm Pharmacol 2011; 63:1522-30. [DOI: 10.1111/j.2042-7158.2011.01356.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abstract
Objectives
The absorption of commonly used ferrous iron salts from intestinal segments at neutral to slightly alkaline pH is low, mainly because soluble ferrous iron is easily oxidized to poorly soluble ferric iron and ferrous iron but not ferric iron is carried by the divalent metal transporter DMT-1. Moreover, ferrous iron frequently causes gastrointestinal side effects. In iron(III)-hydroxide nanoparticles hundreds of ferric iron atoms are safely packed in nanoscaled cores surrounded by a solubilising carbohydrate shell, yet bioavailability from such particles is insufficient when compared with ferrous salts. To increase their intestinal uptake iron(III)-hydroxide nanoparticles were coupled in this study with the protoporphyrin hemin, which undergoes carrier-mediated uptake in the intestine.
Methods
Uptake of iron(III)-hydroxide nanoparticles with hemin covalently coupled by DCC reaction was measured in Caco-2 cells with a colorimetric assay and visualized by transmission electron microscopy.
Key findings
Nanoparticles were taken up by carrier-mediated transport, since uptake was temperature-dependent and increased with an increasing hemin substitution grade. Furthermore, uptake decreased with an increasing concentration of free hemin, due to competition for carrier-mediated uptake.
Conclusions
Hemin-coupled iron(III)-hydroxide nanoparticles were carried by a heme specific transport system, probably via receptor mediated endocytosis. It can be expected that this system shows improved absorption of iron compared with uncoupled iron(III)-hydroxide nanoparticles, which exist on the market today.
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Affiliation(s)
- Markus Richard Jahn
- Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy and Biochemistry, Mainz, Germany
| | - Ibrahim Shukoor
- Institute of Inorganic and Analytical Chemistry, Mainz, Germany
| | - Wolfgang Tremel
- Institute of Inorganic and Analytical Chemistry, Mainz, Germany
| | - Uwe Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Mainz, Germany
| | - Ute Kolb
- Institute of Physical Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Thomas Nawroth
- Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy and Biochemistry, Mainz, Germany
| | - Peter Langguth
- Biopharmacy and Pharmaceutical Technology, Institute of Pharmacy and Biochemistry, Mainz, Germany
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Frezza C, Zheng L, Folger O, Rajagopalan KN, MacKenzie ED, Jerby L, Micaroni M, Chaneton B, Adam J, Hedley A, Kalna G, Tomlinson IPM, Pollard PJ, Watson DG, Deberardinis RJ, Shlomi T, Ruppin E, Gottlieb E. Haem oxygenase is synthetically lethal with the tumour suppressor fumarate hydratase. Nature 2011; 477:225-8. [PMID: 21849978 DOI: 10.1038/nature10363] [Citation(s) in RCA: 373] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 07/11/2011] [Indexed: 02/07/2023]
Abstract
Fumarate hydratase (FH) is an enzyme of the tricarboxylic acid cycle (TCA cycle) that catalyses the hydration of fumarate into malate. Germline mutations of FH are responsible for hereditary leiomyomatosis and renal-cell cancer (HLRCC). It has previously been demonstrated that the absence of FH leads to the accumulation of fumarate, which activates hypoxia-inducible factors (HIFs) at normal oxygen tensions. However, so far no mechanism that explains the ability of cells to survive without a functional TCA cycle has been provided. Here we use newly characterized genetically modified kidney mouse cells in which Fh1 has been deleted, and apply a newly developed computer model of the metabolism of these cells to predict and experimentally validate a linear metabolic pathway beginning with glutamine uptake and ending with bilirubin excretion from Fh1-deficient cells. This pathway, which involves the biosynthesis and degradation of haem, enables Fh1-deficient cells to use the accumulated TCA cycle metabolites and permits partial mitochondrial NADH production. We predicted and confirmed that targeting this pathway would render Fh1-deficient cells non-viable, while sparing wild-type Fh1-containing cells. This work goes beyond identifying a metabolic pathway that is induced in Fh1-deficient cells to demonstrate that inhibition of haem oxygenation is synthetically lethal when combined with Fh1 deficiency, providing a new potential target for treating HLRCC patients.
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Affiliation(s)
- Christian Frezza
- Cancer Research UK, Beatson Institute for Cancer Research, Switchback Road, Glasgow G61 1BD, UK
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19
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Chen C, Samuel TK, Sinclair J, Dailey HA, Hamza I. An intercellular heme-trafficking protein delivers maternal heme to the embryo during development in C. elegans. Cell 2011; 145:720-31. [PMID: 21620137 DOI: 10.1016/j.cell.2011.04.025] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 03/18/2011] [Accepted: 04/27/2011] [Indexed: 01/15/2023]
Abstract
Extracellular free heme can intercalate into membranes and promote damage to cellular macromolecules. Thus it is likely that specific intercellular pathways exist for the directed transport, trafficking, and delivery of heme to cellular destinations, although none have been found to date. Here we show that Caenorhabditis elegans HRG-3 is required for the delivery of maternal heme to developing embryos. HRG-3 binds heme and is exclusively secreted by maternal intestinal cells into the interstitial fluid for transport of heme to extraintestinal cells, including oocytes. HRG-3 deficiency results either in death during embryogenesis or in developmental arrest immediately post-hatching-phenotypes that are fully suppressed by maternal but not zygotic hrg-3 expression. Our results establish a role for HRG-3 as an intercellular heme-trafficking protein.
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Affiliation(s)
- Caiyong Chen
- Department of Animal & Avian Sciences and Department of Cell Biology & Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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20
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Khan AA, Quigley JG. Control of intracellular heme levels: heme transporters and heme oxygenases. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1813:668-82. [PMID: 21238504 PMCID: PMC3079059 DOI: 10.1016/j.bbamcr.2011.01.008] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Revised: 12/31/2010] [Accepted: 01/06/2011] [Indexed: 12/19/2022]
Abstract
Heme serves as a co-factor in proteins involved in fundamental biological processes including oxidative metabolism, oxygen storage and transport, signal transduction and drug metabolism. In addition, heme is important for systemic iron homeostasis in mammals. Heme has important regulatory roles in cell biology, yet excessive levels of intracellular heme are toxic; thus, mechanisms have evolved to control the acquisition, synthesis, catabolism and expulsion of cellular heme. Recently, a number of transporters of heme and heme synthesis intermediates have been described. Here we review aspects of heme metabolism and discuss our current understanding of heme transporters, with emphasis on the function of the cell-surface heme exporter, FLVCR. Knockdown of Flvcr in mice leads to both defective erythropoiesis and disturbed systemic iron homeostasis, underscoring the critical role of heme transporters in mammalian physiology. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
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Affiliation(s)
- Anwar A. Khan
- Department of Medicine, Section of Hematology/Oncology, University of Illinois College of Medicine, 909 South Wolcott Avenue, Chicago, IL-60612
| | - John G. Quigley
- Department of Medicine, Section of Hematology/Oncology, University of Illinois College of Medicine, 909 South Wolcott Avenue, Chicago, IL-60612
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21
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22
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Iron metabolism in thalassemia and sickle cell disease. Mediterr J Hematol Infect Dis 2009; 1:e2009006. [PMID: 21415988 PMCID: PMC3033158 DOI: 10.4084/mjhid.2009.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2009] [Accepted: 10/25/2009] [Indexed: 01/19/2023] Open
Abstract
THERE ARE TWO MAIN MECHANISMS BY WHICH IRON OVERLOAD DEVELOPS IN THALASSEMIAS: increased iron absorption due to ineffective erythropoiesis and blood transfusions. In nontransfused patients with severe thalassemia, abnormal dietary iron absorption increases body iron burden between 2 and 5 g per year. If regular transfusions are required, this doubles the rate of iron accumulation leading to earlier massive iron overload and iron-related damage. Iron metabolism largely differs between thalassemias and sickle cell disease, but chronic transfusion therapy partially normalize many of the disparities between the diseases, making iron overload an important issue to be considered in the management of patients with sickle cell disease too. The present review summarizes the actual knowledge on the regulatory pathways of iron homeostasis. In particular, the data presented indicate the inextricably link between erythropoiesis and iron metabolism and the key role of hepcidin in coordinating iron procurement according to erythropoietic requirement. The role of erythropoietin, hypoxia, erythroid-dependent soluble factors and iron in regulating hepcidin transcription are discussed as well as differences and similarities in iron homeostasis between thalassemia syndromes and sickle cell disease.
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23
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West AR, Oates PS. Mechanisms of heme iron absorption: current questions and controversies. World J Gastroenterol 2008; 14:4101-10. [PMID: 18636652 PMCID: PMC2725368 DOI: 10.3748/wjg.14.4101] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 06/02/2008] [Accepted: 06/09/2008] [Indexed: 02/06/2023] Open
Abstract
Iron is a critical micronutrient, and iron derived from heme contributes a large proportion of the total iron absorbed in a typical Western diet. Heme iron is absorbed by different mechanisms than non-heme iron, but despite considerable study over many years these mechanisms remain poorly understood. This review provides an overview of the importance of heme iron in the diet and discusses the two prevailing hypotheses of heme absorption; namely receptor mediated endocytosis of heme, and direct transport into the intestinal enterocyte by recently discovered heme transporters. A specific emphasis is placed on the questions surrounding the site of heme catabolism and the identity of the enzyme that performs this task. Additionally, we present the hypothesis that a non-heme iron transport protein may be required for heme iron absorption and discuss the experiences of our laboratory in examining this hypothesis.
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24
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Aubry M, Monnier A, Chicault C, Galibert MD, Burgun A, Mosser J. Iron-related transcriptomic variations in Caco-2 cells: In silico perspectives. Biochimie 2008; 90:669-78. [DOI: 10.1016/j.biochi.2008.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Accepted: 01/04/2008] [Indexed: 10/22/2022]
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25
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Uc A, Reszka KJ, Buettner GR, Stokes JB. Tin protoporphyrin induces intestinal chloride secretion by inducing light oxidation processes. Am J Physiol Cell Physiol 2007; 292:C1906-14. [PMID: 17215323 DOI: 10.1152/ajpcell.00550.2006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heme induces Cl(-) secretion in intestinal epithelial cells, most likely via carbon monoxide (CO) generation. The major source of endogenous CO comes from the degradation of heme via heme oxygenase (HO). We hypothesized that an inhibitor of HO activity, tin protoporphyrin (SnPP), may inhibit the stimulatory effect of heme on Cl(-) secretion. To test this hypothesis, we treated an intestinal epithelial cell line (Caco-2 cells) with SnPP. In contrast to our expectations, Caco-2 cells treated with SnPP had an increase in their short-circuit currents (I(sc)) in Ussing chambers. This effect was observed only when the system was exposed to ambient light. SnPP-induced I(sc) was caused by Cl(-) secretion because it was inhibited in Cl(-)-free medium, with ouabain or 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB). The Cl(-) secretion was not via activation of the CFTR, because a specific inhibitor had no effect. Likewise, inhibitors of adenylate cyclase and guanylate cyclase had no effect on the enhanced I(sc). SnPP-induced I(sc) was inhibited by the antioxidant vitamins, alpha-tocopherol and ascorbic acid. Electron paramagnetic resonance experiments confirmed that oxidative reactions were initiated with light in cells loaded with SnPP. These data suggest that SnPP-induced effects may not be entirely due to the inhibition of HO activity but rather to light-induced oxidative processes. These novel effects of SnPP-photosensitized oxidation may also lead to a new understanding of how intestinal Cl(-) secretion can be regulated by the redox environment of the cell.
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Affiliation(s)
- Aliye Uc
- The University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA.
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26
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Latunde-Dada GO, Takeuchi K, Simpson RJ, McKie AT. Haem carrier protein 1 (HCP1): Expression and functional studies in cultured cells. FEBS Lett 2006; 580:6865-70. [PMID: 17156779 DOI: 10.1016/j.febslet.2006.11.048] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Accepted: 11/19/2006] [Indexed: 11/28/2022]
Abstract
Haem released from digestion and breakdown of meat products provides an important source of dietary iron, which is readily absorbed in the proximal intestine. The recent cloning and characterization of a haem carrier protein 1 (HCP 1) has provided a candidate intestinal haem transporter. The current studies describe the expression and functional analysis of HCP1 in cultured Caco-2 cells, a commonly used model of human intestinal cells. HCP1 mRNA expression in other cell types was also studied. The uptake of (55)Fe labeled haem was determined in cells under different experimental conditions and HCP1 expression was measured by RT-PCR and immunohistochemistry. mRNA and protein expressions increased in Caco-2 cells transduced with HCP1 adenoviral plasmid, and consequently (55)Fe haem uptake was higher in these cells. Haem uptake was also increased in fully differentiated Caco-2 cells compared to undifferentiated cells. Preincubation of cells with desferrioxamine (DFO, to deplete cells of iron) had no effect on HCP1 expression or haem uptake. Treatment with CdCl(2) (to induce haem oxygenase, HO-1) enhanced HCP1 expression and increased haem uptake into the cells. HCP1 expression and function were found to be adaptive to the rate of haem degradation by HO-1. Furthermore, HCP1 expression in different cells implies a functional role in tissues other than the duodenum.
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Affiliation(s)
- Gladys O Latunde-Dada
- Department of Biochemistry, School of Biomedical and Health Sciences, Franklin Wilkins Building, King's College London, 150 Stamford Street, London, SE1 9NH, United Kingdom
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27
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Oates PS, West AR. Heme in intestinal epithelial cell turnover, differentiation, detoxification, inflammation, carcinogenesis, absorption and motility. World J Gastroenterol 2006; 12:4281-95. [PMID: 16865768 PMCID: PMC4087737 DOI: 10.3748/wjg.v12.i27.4281] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The gastrointestinal tract is lined by a simple epithelium that undergoes constant renewal involving cell division, differentiation and cell death. In addition, the epithelial lining separates the hostile processes of digestion and absorption that occur in the intestinal lumen from the aseptic environment of the internal milieu by defensive mechanisms that protect the epithelium from being breached. Central to these defensive processes is the synthesis of heme and its catabolism by heme oxygenase (HO). Dietary heme is also an important source of iron for the body which is taken up intact by the enterocyte. This review describes the recent literature on the diverse properties of heme/HO in the intestine tract. The roles of heme/HO in the regulation of the cell cycle/apoptosis, detoxification of xenobiotics, oxidative stress, inflammation, development of colon cancer, heme-iron absorption and intestinal motility are specifically examined.
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28
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Abstract
A number of genetic disorders can result in the accumulation of excess iron in the body. These causes of hereditary hemochromatosis include defects in genes encoding HFE, transferrin receptor 2, ferroportin, hepcidin, and hemojuvelin. Hepcidin, with its cognate receptor, ferroportin, has emerged as a central regulator of iron homeostasis; all of the known causes of hemochromatosis appear to prevent this system from functioning normally. The most common form of primary hemochromatosis is that caused by C282Y mutation of the HFE gene. This mutation is most prevalent among Northern Europeans. Although the frequency of the homozygous genotype is approximately 5 per 1000, the disease itself is quite rare because the clinical penetrance of the genotype is very low.
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Affiliation(s)
- Ernest Beutler
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA.
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29
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Chicault C, Toutain B, Monnier A, Aubry M, Fergelot P, Le Treut A, Galibert MD, Mosser J. Iron-related transcriptomic variations in CaCo-2 cells, an in vitro model of intestinal absorptive cells. Physiol Genomics 2006; 26:55-67. [PMID: 16638840 DOI: 10.1152/physiolgenomics.00297.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Regulation of iron absorption by duodenal enterocytes is essential for the maintenance of homeostasis by preventing iron deficiency or overload. Despite the identification of a number of genes implicated in iron absorption and its regulation, it is likely that further factors remain to be identified. For that purpose, we used a global transcriptomic approach, using the CaCo-2 cell line as an in vitro model of intestinal absorptive cells. Pangenomic screening for variations in gene expression correlating with intracellular iron content allowed us to identify 171 genes. One hundred nine of these genes are clustered into five types of expression profile. This is the first time that most of these genes have been associated with iron metabolism. Functional annotation of these five clusters indicates potential links between the immune response, proteolysis processes, and iron depletion. In contrast, iron overload is associated with cellular metabolism, especially that of lipids and glutathione involving redox function and electron transfer.
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Affiliation(s)
- Céline Chicault
- Centre National de la Recherche Scientifique UMR 6061 Génétique et Développement, Université de Rennes 1, Groupe Oncogénomique, IFR140 GFAS, Faculté de médecine, Rennes, France
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30
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Basireddy M, Lindsay JT, Agarwal A, Balkovetz DF. Epithelial cell polarity and hypoxia influence heme oxygenase-1 expression by heme in renal epithelial cells. Am J Physiol Renal Physiol 2006; 291:F790-5. [PMID: 16622174 DOI: 10.1152/ajprenal.00402.2005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Induction of heme oxygenase-1 (HO-1) in renal tubules occurs as an adaptive and beneficial response in acute renal failure (ARF) following ischemia and nephrotoxins. Using an in vitro model of polarized Madin-Darby canine kidney (MDCK) epithelial cells, we examined apical and basolateral cell surface sensitivity to HO-1 induction by heme. Basolateral exposure to 5 microM hemin (heme chloride) resulted in higher HO-1 induction than did apical exposure. The peak induction of HO-1 by basolateral application of hemin occurred between 12 and 18 h of exposure and was dose dependent. Similar cell surface sensitivity to hemin-induced HO-1 expression was observed using a mouse cortical collecting duct cell line (94D cells). Hepatocyte growth factor (HGF) is known to decrease cell polarity of MDCK cells. Following pretreatment with HGF, apically applied hemin gave greater stimulation of HO-1 expression, whereas HGF alone did not induce HO-1. We also examined the effect of hypoxia on hemin-mediated HO-1 induction. MDCK cells were subjected to hypoxia (1% O(2)) for 24 h to simulate the effects of ischemic ARF. Under hypoxic conditions, both apical as well as basolateral surfaces of MDCK were more sensitive to HO-1 induction by hemin. Hypoxia alone did not induce HO-1 but appeared to potentiate both apical and basolateral sensitivity to hemin-mediated induction. These data demonstrate that the induction of HO-1 expression in polarized renal epithelia by heme is achieved primarily via basolateral exposure. However, under conditions of altered renal epithelial cell polarity and hypoxia, increased HO-1 induction occurs following apical exposure to heme.
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31
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Latunde-Dada GO, Simpson RJ, McKie AT. Recent advances in mammalian haem transport. Trends Biochem Sci 2006; 31:182-8. [PMID: 16487711 DOI: 10.1016/j.tibs.2006.01.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Revised: 01/04/2006] [Accepted: 01/30/2006] [Indexed: 12/12/2022]
Abstract
Haem is a structural component of numerous cellular proteins and contributes greatly to iron metabolic processes in mammals. Haem-carrier protein 1 (HCP1) has recently been cloned and characterized as a putative transporter in the apical region of the duodenum, and is responsible for uptake of haem into the gut cells. Its expression is regulated pre- and post-translationally in hypoxic and iron-deficient mice, respectively. The identification of HCP1 has revealed the long-sought mechanism by which haem--an important source of dietary iron--is absorbed from the diet by the gut. Feline leukaemic virus receptor (FLCVR) and ABC transporter ABCG2, characterized in haematopoietic cells, have also recently been shown to export haem, particularly under stress. FLVCR protects developing erythroid cells from haem toxicity during the early stages of differentiation, and ABCG2 averts protoporphyrin accumulation (particularly under hypoxic conditions). These haem-efflux proteins are expressed in other cells and tissues including the intestine where they might function as apical haem exporters to prevent toxicity in the enterocytes.
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Affiliation(s)
- Gladys O Latunde-Dada
- Department of Biochemistry and Nutrition Sciences Research Division, King's College London, Franklin Wilkin's Building, 150 Stamford Street, London SE1 9NH, UK
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32
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Shayeghi M, Latunde-Dada GO, Oakhill JS, Laftah AH, Takeuchi K, Halliday N, Khan Y, Warley A, McCann FE, Hider RC, Frazer DM, Anderson GJ, Vulpe CD, Simpson RJ, McKie AT. Identification of an Intestinal Heme Transporter. Cell 2005; 122:789-801. [PMID: 16143108 DOI: 10.1016/j.cell.2005.06.025] [Citation(s) in RCA: 474] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Revised: 05/20/2005] [Accepted: 06/17/2005] [Indexed: 12/14/2022]
Abstract
Dietary heme iron is an important nutritional source of iron in carnivores and omnivores that is more readily absorbed than non-heme iron derived from vegetables and grain. Most heme is absorbed in the proximal intestine, with absorptive capacity decreasing distally. We utilized a subtractive hybridization approach to isolate a heme transporter from duodenum by taking advantage of the intestinal gradient for heme absorption. Here we show a membrane protein named HCP 1 (heme carrier protein 1), with homology to bacterial metal-tetracycline transporters, mediates heme uptake by cells in a temperature-dependent and saturable manner. HCP 1 mRNA was highly expressed in duodenum and regulated by hypoxia. HCP 1 protein was iron regulated and localized to the brush-border membrane of duodenal enterocytes in iron deficiency. Our data indicate that HCP 1 is the long-sought intestinal heme transporter.
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Affiliation(s)
- Majid Shayeghi
- Department of Life Sciences, Nutritional Sciences Research Division, Franklin-Wilkins Building, Kings College London, 150 Stamford Street, London SE1 9NN, UK
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33
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Uc A, Husted RF, Giriyappa RL, Britigan BE, Stokes JB. Hemin induces active chloride secretion in Caco-2 cells. Am J Physiol Gastrointest Liver Physiol 2005; 289:G202-8. [PMID: 15805100 DOI: 10.1152/ajpgi.00518.2004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Enterocytes maintain fluid-electrolyte homeostasis by keeping a tight barrier and regulating ion channels. Carbon monoxide (CO), a product of heme degradation, modulates electrolyte transport in kidney and lung epithelium, but its role in regulating intestinal fluid-electrolyte homeostasis has not been studied. The major source of endogenous CO formation comes from the degradation of heme via heme oxygenase. We hypothesized that heme activates electrolyte transport in intestinal epithelial cells. Basolateral hemin treatment increased baseline Caco-2 cell short-circuit currents (I(sc)) twofold (control = 1.96 +/- 0.14 microA/cm(2) vs. hemin = 4.07 +/- 0.16 microA/cm(2), P < 0.01); apical hemin had no effect. Hemin-induced I(sc) was caused by Cl- secretion because it was inhibited in Cl- -free medium, with ouabain, 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), or DIDS. Apical electrogenic Na+ channel inhibitor benzamil had no effect on hemin-induced I(sc). Hemin did not alter the ability of Caco-2 cells to respond maximally to forskolin, but a soluble guanylate cyclase inhibitor, [1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ) inhibited the effects of hemin. A CO-releasing molecule, tricarbonyldichlororuthenium II, induced active Cl- secretion that was also inhibited with ODQ. We conclude that hemin induces active Cl- secretion in Caco-2 cells via a cGMP-dependent pathway. These effects are probably the consequence of CO formation. Heme and CO may be important regulators of intestinal fluid-electrolyte homeostasis.
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Affiliation(s)
- Aliye Uc
- 2865 JPP Pediatrics, University of Iowa Health Care, 200 Hawkins Drive, Iowa City, IA 52242, USA.
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