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Bowser JL, Lee JW, Yuan X, Eltzschig HK. The hypoxia-adenosine link during inflammation. J Appl Physiol (1985) 2017; 123:1303-1320. [PMID: 28798196 DOI: 10.1152/japplphysiol.00101.2017] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 07/18/2017] [Accepted: 08/06/2017] [Indexed: 12/23/2022] Open
Abstract
Hypoxic tissue conditions occur during a number of inflammatory diseases and are associated with the breakdown of barriers and induction of proinflammatory responses. At the same time, hypoxia is also known to induce several adaptive and tissue-protective pathways that dampen inflammation and protect tissue integrity. Hypoxia-inducible factors (HIFs) that are stabilized during inflammatory or hypoxic conditions are at the center of mediating these responses. In the past decade, several genes regulating extracellular adenosine metabolism and signaling have been identified as being direct targets of HIFs. Here, we discuss the relationship between inflammation, hypoxia, and adenosine and that HIF-driven adenosine metabolism and signaling is essential in providing tissue protection during inflammatory conditions, including myocardial injury, inflammatory bowel disease, and acute lung injury. We also discuss how the hypoxia-adenosine link can be targeted therapeutically in patients as a future treatment approach for inflammatory diseases.
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Affiliation(s)
- Jessica L Bowser
- Department of Anesthesiology, The University of Texas Health Science Center at Houston, McGovern Medical School, Houston, Texas
| | - Jae W Lee
- Department of Anesthesiology, The University of Texas Health Science Center at Houston, McGovern Medical School, Houston, Texas
| | - Xiaoyi Yuan
- Department of Anesthesiology, The University of Texas Health Science Center at Houston, McGovern Medical School, Houston, Texas
| | - Holger K Eltzschig
- Department of Anesthesiology, The University of Texas Health Science Center at Houston, McGovern Medical School, Houston, Texas
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102
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Wright CR, Allsopp GL, Addinsall AB, McRae NL, Andrikopoulos S, Stupka N. A Reduction in Selenoprotein S Amplifies the Inflammatory Profile of Fast-Twitch Skeletal Muscle in the mdx Dystrophic Mouse. Mediators Inflamm 2017; 2017:7043429. [PMID: 28592916 PMCID: PMC5448157 DOI: 10.1155/2017/7043429] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/23/2017] [Accepted: 03/07/2017] [Indexed: 12/20/2022] Open
Abstract
Excessive inflammation is a hallmark of muscle myopathies, including Duchenne muscular dystrophy (DMD). There is interest in characterising novel genes that regulate inflammation due to their potential to modify disease progression. Gene polymorphisms in Selenoprotein S (Seps1) are associated with elevated proinflammatory cytokines, and in vitro SEPS1 is protective against inflammatory stress. Given that SEPS1 is highly expressed in skeletal muscle, we investigated whether the genetic reduction of Seps1 exacerbated inflammation in the mdx mouse. F1 male mdx mice with a heterozygous Seps1 deletion (mdx:Seps1-/+) were generated. The mdx:Seps1-/+ mice had a 50% reduction in SEPS1 protein expression in hindlimb muscles. In the extensor digitorum longus (EDL) muscles, mRNA expression of monocyte chemoattractant protein 1 (Mcp-1) (P = 0.034), macrophage marker F4/80 (P = 0.030), and transforming growth factor-β1 (Tgf-β1) (P = 0.056) were increased in mdx:Seps1-/+ mice. This was associated with a reduction in muscle fibre size; however, ex vivo EDL muscle strength and endurance were unaltered. In dystrophic slow twitch soleus muscles, SEPS1 reduction had no effect on the inflammatory profile nor function. In conclusion, the genetic reduction of Seps1 appears to specifically exacerbate the inflammatory profile of fast-twitch muscle fibres, which are typically more vulnerable to degeneration in dystrophy.
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MESH Headings
- Animals
- Blotting, Western
- Body Composition/genetics
- Body Composition/physiology
- Female
- Immunohistochemistry
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Inbred mdx
- Muscle Contraction/physiology
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Fast-Twitch/physiology
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/physiology
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/physiology
- Muscular Dystrophy, Duchenne/metabolism
- Real-Time Polymerase Chain Reaction
- Selenoproteins/genetics
- Selenoproteins/metabolism
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Affiliation(s)
- Craig Robert Wright
- Institute for Physical Activity and Nutrition Research (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
| | - Giselle Larissa Allsopp
- Institute for Physical Activity and Nutrition Research (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia
| | - Alex Bernard Addinsall
- Molecular Medical Research SRC, School of Medicine, Deakin University, Geelong, VIC, Australia
| | - Natasha Lee McRae
- Molecular Medical Research SRC, School of Medicine, Deakin University, Geelong, VIC, Australia
| | | | - Nicole Stupka
- Molecular Medical Research SRC, School of Medicine, Deakin University, Geelong, VIC, Australia
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103
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Manresa MC, Taylor CT. Hypoxia Inducible Factor (HIF) Hydroxylases as Regulators of Intestinal Epithelial Barrier Function. Cell Mol Gastroenterol Hepatol 2017; 3:303-315. [PMID: 28462372 PMCID: PMC5404106 DOI: 10.1016/j.jcmgh.2017.02.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 02/09/2017] [Indexed: 12/12/2022]
Abstract
Human health is dependent on the ability of the body to extract nutrients, fluids, and oxygen from the external environment while at the same time maintaining a state of internal sterility. Therefore, the cell layers that cover the surface areas of the body such as the lung, skin, and gastrointestinal mucosa provide vital semipermeable barriers that allow the transport of essential nutrients, fluid, and waste products, while at the same time keeping the internal compartments free of microbial organisms. These epithelial surfaces are highly specialized and differ in their anatomic structure depending on their location to provide appropriate and effective site-specific barrier function. Given this important role, it is not surprising that significant disease often is associated with alterations in epithelial barrier function. Examples of such diseases include inflammatory bowel disease, chronic obstructive pulmonary disease, and atopic dermatitis. These chronic inflammatory disorders often are characterized by diminished tissue oxygen levels (hypoxia). Hypoxia triggers an adaptive transcriptional response governed by hypoxia-inducible factors (HIFs), which are repressed by a family of oxygen-sensing HIF hydroxylases. Here, we review recent evidence suggesting that pharmacologic hydroxylase inhibition may be of therapeutic benefit in inflammatory bowel disease through the promotion of intestinal epithelial barrier function through both HIF-dependent and HIF-independent mechanisms.
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Key Words
- CD, Crohn’s disease
- DMOG, dimethyloxalylglycine
- DSS, dextran sodium sulfate
- Epithelial Barrier
- FIH, factor inhibiting hypoxia-inducible factor
- HIF, hypoxia-inducible factor
- Hypoxia
- Hypoxia-Inducible Factor (HIF) Hydroxylases
- IBD, inflammatory bowel disease
- IL, interleukin
- Inflammatory Bowel Disease
- NF-κB, nuclear factor-κB
- PHD, hypoxia-inducible factor–prolyl hydroxylases
- TFF, trefoil factor
- TJ, tight junction
- TLR, Toll-like receptor
- TNF-α, tumor necrosis factor α
- UC, ulcerative colitis
- ZO, zonula occludens
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Affiliation(s)
- Mario C. Manresa
- Conway Institute of Biomolecular and Biomedical Research, Belfield, Dublin, Ireland
- Charles Institute of Dermatology, Belfield, Dublin, Ireland
| | - Cormac T. Taylor
- Conway Institute of Biomolecular and Biomedical Research, Belfield, Dublin, Ireland
- Charles Institute of Dermatology, Belfield, Dublin, Ireland
- Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland
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104
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Fagundes RR, Taylor CT. Determinants of hypoxia-inducible factor activity in the intestinal mucosa. J Appl Physiol (1985) 2017; 123:1328-1334. [PMID: 28408694 DOI: 10.1152/japplphysiol.00203.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 03/28/2017] [Accepted: 04/07/2017] [Indexed: 12/16/2022] Open
Abstract
The intestinal mucosa is exposed to fluctuations in oxygen levels due to constantly changing rates of oxygen demand and supply and its juxtaposition with the anoxic environment of the intestinal lumen. This frequently results in a state of hypoxia in the healthy mucosa even in the physiologic state. Furthermore, pathophysiologic hypoxia (which is more severe and extensive) is associated with chronic inflammatory diseases including inflammatory bowel disease (IBD). The hypoxia-inducible factor (HIF), a ubiquitously expressed regulator of cellular adaptation to hypoxia, is central to both the adaptive and the inflammatory responses of cells of the intestinal mucosa in IBD patients. In this review, we discuss the microenvironmental factors which influence the level of HIF activity in healthy and inflamed intestinal mucosae and the consequences that increased HIF activity has for tissue function and disease progression.
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Affiliation(s)
- Raphael R Fagundes
- Graduate School of Medical Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; and.,UCD Conway Institute, Systems Biology Ireland and School of Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - Cormac T Taylor
- UCD Conway Institute, Systems Biology Ireland and School of Medicine, University College Dublin, Belfield, Dublin, Ireland
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105
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Zenewicz LA. Oxygen Levels and Immunological Studies. Front Immunol 2017; 8:324. [PMID: 28377771 PMCID: PMC5359232 DOI: 10.3389/fimmu.2017.00324] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 03/07/2017] [Indexed: 01/21/2023] Open
Affiliation(s)
- Lauren A Zenewicz
- Department of Microbiology and Immunology, College of Medicine, University of Oklahoma Health Sciences Center , Oklahoma City, OK , USA
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106
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Lomax AE, Pradhananga S, Bertrand PP. Plasticity of neuroeffector transmission during bowel inflammation 1. Am J Physiol Gastrointest Liver Physiol 2017; 312:G165-G170. [PMID: 28082285 DOI: 10.1152/ajpgi.00365.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/03/2017] [Accepted: 01/03/2017] [Indexed: 01/31/2023]
Abstract
Altered gastrointestinal (GI) function contributes to the debilitating symptoms of inflammatory bowel diseases (IBD). Nerve circuits contained within the gut wall and outside of the gut play important roles in modulating motility, mucosal fluid transport, and blood flow. The structure and function of these neuronal populations change during IBD. Superimposed on this plasticity is a diminished responsiveness of effector cells - smooth muscle cells, enterocytes, and vascular endothelial cells - to neurotransmitters. The net result is a breakdown in the precisely orchestrated coordination of motility, fluid secretion, and GI blood flow required for health. In this review, we consider how inflammation-induced changes to the effector innervation of these tissues, and changes to the tissues themselves, contribute to defective GI function in models of IBD. We also explore the evidence that reversing neuronal plasticity is sufficient to normalize function during IBD.
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Affiliation(s)
- Alan E Lomax
- Gastrointestinal Disease Research Unit, Queen's University, Kingston, Ontario, Canada; and
| | - Sabindra Pradhananga
- Gastrointestinal Disease Research Unit, Queen's University, Kingston, Ontario, Canada; and
| | - Paul P Bertrand
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria, Australia
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107
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Kim DS, Kim SH, Kee JY, Han YH, Park J, Mun JG, Joo MJ, Jeon YD, Kim SJ, Park SH, Park SJ, Um JY, Hong SH. Eclipta prostrataImproves DSS-Induced Colitis through Regulation of Inflammatory Response in Intestinal Epithelial Cells. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2017; 45:1047-1060. [DOI: 10.1142/s0192415x17500562] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Eclipta prostrata (EP) and its compounds are known to have several pharmacological effects including anti-inflammatory effects. In the present study, we demonstrated that EP improves the dextran sulfate sodium (DSS)-induced colitis symptoms such as body weight loss, colon length shortening and disease activity index. In DSS-induced colitis tissue, EP controls the protein expressions of cyclooxygenase-2 (COX-2) and hypoxia inducible factor-1[Formula: see text] (HIF-1[Formula: see text]). In addition, the release of prostaglandin E2and vascular endothelial growth factor-A were significantly reduced by EP administration. EP also inhibited COX-2 and HIF-1[Formula: see text] expressions in the tumor necrosis factor-[Formula: see text] stimulated HT-29 cells. These inhibitory effects of EP occurred by reducing the phosphorylation of I[Formula: see text]B and the translocation of the nuclear factor-[Formula: see text]B (NF-[Formula: see text]B). Additionally, we found through HPLC analysis that wedelolactone, which is an inhibitor of NF-[Formula: see text]B transcription, was contained in water extract of EP. These results indicate that EP can improve colitis symptoms through the modulation of immune function in intestinal epithelial cells and suggests that EP has the potential therapeutic effect to intestinal inflammation.
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Affiliation(s)
- Dae-Seung Kim
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwnag University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Sung-Hee Kim
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwnag University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Ji-Ye Kee
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwnag University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Yo-Han Han
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwnag University, Iksan, Jeonbuk 54538, Republic of Korea
| | - JinBong Park
- Department of Pharmacology, College of Korean Medicine, Kyung Hee University, Dongdaemun-gu, Seoul 02453, Republic of Korea
| | - Jeong-Geon Mun
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwnag University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Moon-Jung Joo
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwnag University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Yong-Deok Jeon
- Department of Herbal Medicine Resources, Chonbuk National University, Iksan, Jeonbuk 54596, Republic of Korea
| | - Su-Jin Kim
- Department of Cosmeceutical Science, DaeguHanny University, Kyungsan, Kyungbuk 38610, Republic of Korea
| | - Sang-Hyun Park
- Isotope Sciences Lab, Korea Atomic Energy Research Institute, 1266 Shinjeong-Dong, Jeongeup, Jeonbuk 56212, Republic of Korea
| | - Sung-Joo Park
- Department of Herbology, College of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 54538, Republic of Korea
| | - Jae-Young Um
- Department of Pharmacology, College of Korean Medicine, Kyung Hee University, Dongdaemun-gu, Seoul 02453, Republic of Korea
| | - Seung-Heon Hong
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwnag University, Iksan, Jeonbuk 54538, Republic of Korea
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108
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Zeitouni NE, Chotikatum S, von Köckritz-Blickwede M, Naim HY. The impact of hypoxia on intestinal epithelial cell functions: consequences for invasion by bacterial pathogens. Mol Cell Pediatr 2016; 3:14. [PMID: 27002817 PMCID: PMC4803720 DOI: 10.1186/s40348-016-0041-y] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/13/2016] [Indexed: 02/06/2023] Open
Abstract
The maintenance of oxygen homeostasis in human tissues is mediated by several cellular adaptations in response to low-oxygen stress, called hypoxia. A decrease in tissue oxygen levels is initially counteracted by increasing local blood flow to overcome diminished oxygenation and avoid hypoxic stress. However, studies have shown that the physiological oxygen concentrations in several tissues are much lower than atmospheric (normoxic) conditions, and the oxygen supply is finely regulated in individual cell types. The gastrointestinal tract has been described to subsist in a state of physiologically low oxygen level and is thus depicted as a tissue in the state of constant low-grade inflammation. The intestinal epithelial cell layer plays a vital role in the immune response to inflammation and infections that occur within the intestinal tissue and is involved in many of the adaptation responses to hypoxic stress. This is especially relevant in the context of inflammatory disorders, such as inflammatory bowel disease (IBD). Therefore, this review aims to describe the intestinal epithelial cellular response to hypoxia and the consequences for host interactions with invading gastrointestinal bacterial pathogens.
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Affiliation(s)
- Nathalie E. Zeitouni
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Sucheera Chotikatum
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Maren von Köckritz-Blickwede
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Hannover, Germany
| | - Hassan Y. Naim
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
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109
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de Vallière C, Cosin-Roger J, Simmen S, Atrott K, Melhem H, Zeitz J, Madanchi M, Tcymbarevich I, Fried M, Kullak-Ublick GA, Vavricka SR, Misselwitz B, Seuwen K, Wagner CA, Eloranta JJ, Rogler G, Ruiz PA. Hypoxia Positively Regulates the Expression of pH-Sensing G-Protein-Coupled Receptor OGR1 (GPR68). Cell Mol Gastroenterol Hepatol 2016; 2:796-810. [PMID: 28174749 PMCID: PMC5247318 DOI: 10.1016/j.jcmgh.2016.06.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 06/17/2016] [Indexed: 12/11/2022]
Abstract
BACKGROUND & AIMS A novel family of proton-sensing G-protein-coupled receptors, including ovarian cancer G-protein-coupled receptor 1 (OGR1) (GPR68) has been identified to play a role in pH homeostasis. Hypoxia is known to change tissue pH as a result of anaerobic glucose metabolism through the stabilization of hypoxia-inducible factor-1α. We investigated how hypoxia regulates the expression of OGR1 in the intestinal mucosa and associated cells. METHODS OGR1 expression in murine tumors, human colonic tissue, and myeloid cells was determined by quantitative reverse-transcription polymerase chain reaction. The influence of hypoxia on OGR1 expression was studied in monocytes/macrophages and intestinal mucosa of inflammatory bowel disease (IBD) patients. Changes in OGR1 expression in MonoMac6 (MM6) cells under hypoxia were determined upon stimulation with tumor necrosis factor (TNF), in the presence or absence of nuclear factor-κB (NF-κB) inhibitors. To study the molecular mechanisms involved, chromatin immunoprecipitation analysis of the OGR1 promoter was performed. RESULTS OGR1 expression was significantly higher in tumor tissue compared with normal murine colon tissue. Hypoxia positively regulated the expression of OGR1 in MM6 cells, mouse peritoneal macrophages, primary human intestinal macrophages, and colonic tissue from IBD patients. In MM6 cells, hypoxia-enhanced TNF-induced OGR1 expression was reversed by inhibition of NF-κB. In addition to the effect of TNF and hypoxia, OGR1 expression was increased further at low pH. Chromatin immunoprecipitation analysis showed that HIF-1α, but not NF-κB, binds to the promoter of OGR1 under hypoxia. CONCLUSIONS The enhancement of TNF- and hypoxia-induced OGR1 expression under low pH points to a positive feed-forward regulation of OGR1 activity in acidic conditions, and supports a role for OGR1 in the pathogenesis of IBD.
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Key Words
- AICAR, 5-aminoimidazole-4-carboxamide-1-β-4-ribofuranoside
- CD, Crohn's disease
- ChIP, chromatin immunoprecipitation
- FCS, fetal calf serum
- GPR, G-protein–coupled receptor
- GRP65
- HIF, hypoxia-inducible factor
- HV, healthy volunteer
- IBD, inflammatory bowel disease
- IEC, intestinal epithelial cell
- IFN, interferon
- IL, interleukin
- Inflammation
- Inflammatory Bowel Disease
- MM6, MonoMac 6
- NF-κB, nuclear factor-κB
- OGR1, ovarian cancer G-protein–coupled receptor 1 (GPR68)
- Ovarian Cancer G-Protein–Coupled Receptor
- RT-qPCR, quantitative reverse-transcription polymerase chain reaction
- SPARC, secreted protein acidic and rich in cysteine
- TDAG8
- TDAG8, T-cell death-associated gene 8 (GPR65)
- TNF, tumor necrosis factor
- Th, T-helper
- UC, ulcerative colitis
- WT, wild type
- mRNA, messenger RNA
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Affiliation(s)
- Cheryl de Vallière
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Jesus Cosin-Roger
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland; Department of Pharmacology and Biomedical Research Networking Center in Hepatic and Digestive Diseases (CIBERehd), Faculty of Medicine, University of Valencia, Valencia, Spain
| | - Simona Simmen
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Kirstin Atrott
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Hassan Melhem
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Jonas Zeitz
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Mehdi Madanchi
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Irina Tcymbarevich
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Michael Fried
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Gerd A Kullak-Ublick
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Zurich, Switzerland
| | - Stephan R Vavricka
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Benjamin Misselwitz
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Klaus Seuwen
- Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University Hospital Zurich, Zurich, Switzerland
| | - Jyrki J Eloranta
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Zurich, Switzerland
| | - Gerhard Rogler
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Pedro A Ruiz
- Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
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110
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Nolan KA, Scholz CC. Hypoxia: from basic mechanisms to therapeutics - a meeting report on the Keystone and HypoxiaNet Symposium. HYPOXIA 2016; 3:67-72. [PMID: 27774483 PMCID: PMC5045090 DOI: 10.2147/hp.s83240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In May 2015, the hypoxia research community came together at the largest meeting in this field to date, to present and discuss their most recent and mainly unpublished findings. This meeting report aims to summarize the data presented at this conference, which were broadly separated into the areas of the cellular hypoxic response, the relevance of the hypoxic response in health and disease, and the development of new therapeutics targeting the hypoxic response.
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Affiliation(s)
- Karen A Nolan
- Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Carsten C Scholz
- Institute of Physiology, University of Zürich, Zürich, Switzerland
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111
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Jin Y, Blikslager AT. Myosin light chain kinase mediates intestinal barrier dysfunction via occludin endocytosis during anoxia/reoxygenation injury. Am J Physiol Cell Physiol 2016; 311:C996-C1004. [PMID: 27760753 DOI: 10.1152/ajpcell.00113.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 10/13/2016] [Indexed: 01/13/2023]
Abstract
Intestinal anoxia/reoxygenation (A/R) injury induces loss of barrier function followed by epithelial repair. Myosin light chain kinase (MLCK) has been shown to alter barrier function via regulation of interepithelial tight junctions, but has not been studied in intestinal A/R injury. We hypothesized that A/R injury would disrupt tight junction barrier function via MLCK activation and myosin light chain (MLC) phosphorylation. Caco-2BBe1 monolayers were subjected to anoxia for 2 h followed by reoxygenation in 21% O2, after which barrier function was determined by measuring transepithelial electrical resistance (TER) and FITC-dextran flux. Tight junction proteins and MLCK signaling were assessed by Western blotting, real-time PCR, or immunofluorescence microscopy. The role of MLCK was further investigated with select inhibitors (ML-7 and peptide 18) by using in vitro and ex vivo models. Following A/R injury, there was a significant increase in paracellular permeability compared with control cells, as determined by TER and dextran fluxes (P < 0.05). The tight junction protein occludin was internalized during A/R injury and relocalized to the region of the tight junction after 4 h of recovery. MLC phosphorylation was significantly increased by A/R injury (P < 0.05), and treatment with the MLCK inhibitor peptide 18 attenuated the increased epithelial monolayer permeability and occludin endocytosis caused by A/R injury. Application of MLCK inhibitors to ischemia-injured porcine ileal mucosa induced significant increases in TER and reduced mucosal-to-serosal fluxes of 3H-labeled mannitol. These data suggest that MLCK-induced occludin endocytosis mediates intestinal epithelial barrier dysfunction during A/R injury. Our results also indicate that MLCK-dependent occludin regulation may be a target for the therapeutic treatment of ischemia/reperfusion injury.
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Affiliation(s)
- Younggeon Jin
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina
| | - Anthony T Blikslager
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina
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112
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Halligan DN, Murphy SJE, Taylor CT. The hypoxia-inducible factor (HIF) couples immunity with metabolism. Semin Immunol 2016; 28:469-477. [PMID: 27717536 DOI: 10.1016/j.smim.2016.09.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 09/23/2016] [Accepted: 09/30/2016] [Indexed: 12/16/2022]
Abstract
Crosstalk between metabolic and immune pathways has recently become appreciated to be key to the regulation of host defence. The hypoxia-inducible factor (HIF) is a transcription factor which was initially described as a ubiquitous master regulator of the transcriptional response to hypoxia. In this role, HIF regulates genes promoting adaptation to hypoxia including a number which influence the cellular metabolic strategy of a cell. It has more recently been appreciated that the regulation of HIF is not restricted to oxygen-dependent pathways, and is now known to be mediated by a number of additional metabolic and immune cues including metabolites and cytokines respectively. Furthermore, our understanding of the functional role of HIF has expanded to it now being appreciated as a major regulator of host immunity. This places HIF in an ideal position to act as a regulatory hub which links metabolic activity with immunity. In this review we synthesise recent data which identifies HIF as both a target and effector for metabolic and immune processes. Developing our understanding of the role of HIF in this context will uncover new therapeutic targets for inflammatory and infectious disease.
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Affiliation(s)
- Doug N Halligan
- Conway Institute, Charles Institute & Systems Biology Ireland, University College Dublin, Belfield Dublin 4, Ireland; Sigmoid Pharma, Invent Centre, Dublin City University, Dublin 9, Ireland
| | - Stephen J E Murphy
- Conway Institute, Charles Institute & Systems Biology Ireland, University College Dublin, Belfield Dublin 4, Ireland
| | - Cormac T Taylor
- Conway Institute, Charles Institute & Systems Biology Ireland, University College Dublin, Belfield Dublin 4, Ireland; IRCAN, Centre A. Lacassagne, University of Nice-Sophia Antipolis, 33 Avenue Valombrose, 06107 Nice, France; Centre Scientifique de Monaco (CSM), 8, Quai Antoine Premier, Monaco.
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113
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Walls J, Sinclair L, Finlay D. Nutrient sensing, signal transduction and immune responses. Semin Immunol 2016; 28:396-407. [DOI: 10.1016/j.smim.2016.09.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 09/13/2016] [Indexed: 12/11/2022]
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114
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Lin N, Simon MC. Hypoxia-inducible factors: key regulators of myeloid cells during inflammation. J Clin Invest 2016; 126:3661-3671. [PMID: 27599290 DOI: 10.1172/jci84426] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hypoxia is a prominent characteristic of many acute or chronic inflammatory diseases, and exerts significant influence on their progression. Macrophages and neutrophils are major cellular components of innate immunity and contribute not only to O2 deprivation at the site of inflammation, but also alter many of their functions in response to hypoxia to either facilitate or suppress inflammation. Hypoxia stabilizes HIF-αs in macrophages and neutrophils, and these O2-sensitive transcription factors are key regulators of inflammatory responses in myeloid cells. In this review, we will summarize our current understanding of the role of HIF-αs in shaping macrophage and neutrophil functions in the pathogenesis and progression of multiple inflammatory diseases.
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Taylor CT, Doherty G, Fallon PG, Cummins EP. Hypoxia-dependent regulation of inflammatory pathways in immune cells. J Clin Invest 2016; 126:3716-3724. [PMID: 27454299 DOI: 10.1172/jci84433] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Uncontrolled inflammation underpins a diverse range of diseases where effective therapy remains an unmet clinical need. Hypoxia is a prominent feature of the inflammatory microenvironment that regulates key transcription factors including HIF and NF-κB in both innate and adaptive immune cells. In turn, altered activity of the pathways controlled by these factors can affect the course of inflammation through the regulation of immune cell development and function. In this review, we will discuss these pathways and the oxygen sensors that confer hypoxic sensitivity in immune cells. Furthermore, we will describe how hypoxia-dependent pathways contribute to immunity and discuss their potential as therapeutic targets in inflammatory and infectious disease.
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Aggressiveness Niche: Can It Be the Foster Ground for Cancer Metastasis Precursors? Stem Cells Int 2016; 2016:4829106. [PMID: 27493669 PMCID: PMC4963571 DOI: 10.1155/2016/4829106] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/15/2016] [Indexed: 12/26/2022] Open
Abstract
The relationship between tumor initiation and tumor progression can follow a linear projection in which all tumor cells are equally endowed with the ability to progress into metastasis. Alternatively, not all tumor cells are equal genetically and/or epigenetically, and only few cells are induced to become metastatic tumor cells. The location of these cells within the tumor can also impact the fate of these cells. The most inner core of a tumor where an elevated pressure of adverse conditions forms, such as necrosis-induced inflammation and hypoxia-induced immunosuppressive environment, seems to be the most fertile ground to generate such tumor cells with metastatic potential. Here we will call this necrotic/hypoxic core the “aggressiveness niche” and will present data to support its involvement in generating these metastatic precursors. Within this niche, interaction of hypoxia-surviving cells with the inflammatory microenvironment influenced by newly recruited mesenchymal stromal cells (MSCs), tumor-associated macrophages (TAMs), and other types of cells and the establishment of bidirectional interactions between them elevate the aggressiveness of these tumor cells. Additionally, immune evasion properties induced in these cells most likely contribute in the formation and maintenance of such aggressiveness niche.
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Fitzpatrick SF, Fábián Z, Schaible B, Lenihan CR, Schwarzl T, Rodriguez J, Zheng X, Li Z, Tambuwala MM, Higgins DG, O'Meara Y, Slattery C, Manresa MC, Fraisl P, Bruning U, Baes M, Carmeliet P, Doherty G, von Kriegsheim A, Cummins EP, Taylor CT. Prolyl hydroxylase-1 regulates hepatocyte apoptosis in an NF-κB-dependent manner. Biochem Biophys Res Commun 2016; 474:579-586. [DOI: 10.1016/j.bbrc.2016.04.085] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 04/18/2016] [Indexed: 01/21/2023]
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Stevens JF, Maier CS. The Chemistry of Gut Microbial Metabolism of Polyphenols. PHYTOCHEMISTRY REVIEWS : PROCEEDINGS OF THE PHYTOCHEMICAL SOCIETY OF EUROPE 2016; 15:425-444. [PMID: 27274718 PMCID: PMC4888912 DOI: 10.1007/s11101-016-9459-z] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 03/02/2016] [Indexed: 05/18/2023]
Abstract
Gut microbiota contribute to the metabolism of dietary polyphenols and affect the bioavailability of both the parent polyphenols and their metabolites. Although there is a large number of reports of specific polyphenol metabolites, relatively little is known regarding the chemistry and enzymology of the metabolic pathways utilized by specific microbial species and taxa, which is the focus of this review. Major classes of dietary polyphenols include monomeric and oligomeric catechins (proanthocyanidins), flavonols, flavanones, ellagitannins, and isoflavones. Gut microbial metabolism of representatives of these polyphenol classes can be classified as A- and C-ring cleavage (retro Claisen reactions), C-ring cleavage mediated by dioxygenases, dehydroxylations (decarboxylation or reduction reactions followed by release of H2O molecules), and hydrogenations of alkene moieties in polyphenols, such as resveratrol, curcumin, and isoflavones (mediated by NADPH-dependent reductases). The qualitative and quantitative metabolic output of the gut microbiota depends to a large extent on the metabolic capacity of individual taxa, which emphasizes the need for assessment of functional analysis in conjunction with determinations of gut microbiota compositions.
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Affiliation(s)
- Jan F Stevens
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, Oregon 97330; Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97330
| | - Claudia S Maier
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97330; Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97330
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Wu J, Sun X, Wu Q, Li H, Li L, Feng J, Zhang S, Xu L, Li K, Li X, Wang X, Chen H. Disrupted intestinal structure in a rat model of intermittent hypoxia. Mol Med Rep 2016; 13:4407-13. [PMID: 27035757 DOI: 10.3892/mmr.2016.5068] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 03/09/2016] [Indexed: 02/05/2023] Open
Abstract
Obstructive sleep apnea (OSA) is a chronic condition characterized by chronic intermittent hypoxia (IH) and subsequent reoxygenation (ROX). The gastrointestinal system, which is particularly sensitive to tissue hypoxia and reduced perfusion, is likely to be affected by OSA. A rat model of IH was used to analyze oxidative stress-associated genes and tight junction proteins by reverse transcription‑quantitative polymerase chain reaction. Subsequently, altered morphology of the duodenal mucosa and elevated Chiu scores were observed in the IH‑exposed rats. In addition, IH exposure resulted in upregulation of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, NADPH oxidase 2 and p22phox, in the small intestine, and upregulation of transcription factors, including hypoxia‑inducible factor-1, nuclear factor‑κB and activator protein-1. Furthermore, the mRNA expression levels of intestinal tight junction (TJ)-related proteins, claudin-1 and claudin-4, were decreased in the IH‑exposed group, as compared with in the control group. In conclusion, the present study demonstrated that OSA, which is characterized by IH and ROX, may lead to disruption of the duodenum. The mechanism underlying the effects of OSA on duodenal morphology may be associated with increased oxidative stress and activation of transcription factors, subsequently inducing intestinal TJ disruption and intestinal injury.
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Affiliation(s)
- Junping Wu
- Department of Basic Medicine, Haihe Clinical College, Tianjin Medical University, Tianjin 300350, P.R. China
| | - Xin Sun
- Department of Basic Medicine, Haihe Clinical College, Tianjin Medical University, Tianjin 300350, P.R. China
| | - Qi Wu
- Department of Basic Medicine, Haihe Clinical College, Tianjin Medical University, Tianjin 300350, P.R. China
| | - Hongwei Li
- Department of Basic Medicine, Haihe Clinical College, Tianjin Medical University, Tianjin 300350, P.R. China
| | - Li Li
- Department of Respiratory Medicine, Tianjin Haihe Hospital, Tianjin 300350, P.R. China
| | - Jing Feng
- Respiratory Department, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Subei Zhang
- Department of Basic Medicine, Haihe Clinical College, Tianjin Medical University, Tianjin 300350, P.R. China
| | - Long Xu
- Department of Basic Medicine, Haihe Clinical College, Tianjin Medical University, Tianjin 300350, P.R. China
| | - Kuan Li
- Department of Basic Medicine, Haihe Clinical College, Tianjin Medical University, Tianjin 300350, P.R. China
| | - Xue Li
- Department of Basic Medicine, Haihe Clinical College, Tianjin Medical University, Tianjin 300350, P.R. China
| | - Xing Wang
- Department of Respiratory Medicine, Tianjin Haihe Hospital, Tianjin 300350, P.R. China
| | - Huaiyong Chen
- Department of Basic Medicine, Haihe Clinical College, Tianjin Medical University, Tianjin 300350, P.R. China
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Bakirtzi K, Law IKM, Xue X, Iliopoulos D, Shah YM, Pothoulakis C. Neurotensin Promotes the Development of Colitis and Intestinal Angiogenesis via Hif-1α-miR-210 Signaling. THE JOURNAL OF IMMUNOLOGY 2016; 196:4311-21. [PMID: 27076683 DOI: 10.4049/jimmunol.1501443] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 03/04/2016] [Indexed: 12/15/2022]
Abstract
Neurotensin (NT) via its receptor 1 (NTR1) modulates the development of colitis, decreases HIF-1α/PHD2 interaction, stabilizes and increases HIF-1α transcriptional activity, and promotes intestinal angiogenesis. HIF-1α induces miR-210 expression, whereas miR-210 is strongly upregulated in response to NT in NCM460 human colonic epithelial cells overexpressing NTR1 (NCM460-NTR1). In this study, we examined whether NT activates a NTR1-HIF-1α-miR-210 cascade using in vitro (NCM460-NTR1 cells) and in vivo (transgenic mice overexpressing [HIF-1α-OE] or lacking HIF-1α [HIF-1α-knockout (KO)] in intestinal epithelial cells and mice lacking NTR1 [NTR1-KO]) models. Pretreatment of NCM460-NTR1 cells with the HIF-1α inhibitor PX-478 or silencing of HIF-1α (small interfering HIF-1α) attenuated miR-210 expression in response to NT. Intracolonic 2,4,6-trinitrobenzenesulfonic acid (TNBS) administration (2-d model) increased colonic miR-210 expression that was significantly reduced in NTR1-KO, HIF-1α-KO mice, and wild-type mice pretreated intracolonically with locked nucleic acid anti-miR-210. In contrast, HIF-1α-OE mice showed increased miR-210 expression at baseline that was further increased following TNBS administration. HIF-1α-OE mice had also exacerbated TNBS-induced neovascularization compared with TNBS-exposed wild-type mice. TNBS-induced neovascularization was attenuated in HIF-1α-KO mice, or mice pretreated intracolonically with anti-miR-210. Intracolonic anti-miR-210 also reduced colitis in response to TNBS (2 d). Importantly, miR-210 expression was increased in tissue samples from ulcerative colitis patients. We conclude that NT exerts its proinflammatory and proangiogenic effects during acute colitis via a NTR1-prolyl hydroxylase 2/HIF-1α-miR-210 signaling pathway. Our results also demonstrate that miR-210 plays a proinflammatory role in the development of colitis.
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Affiliation(s)
- Kyriaki Bakirtzi
- Inflammatory Bowel Disease Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Ivy Ka Man Law
- Inflammatory Bowel Disease Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Xiang Xue
- Division of Gastroenterology, Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Dimitrios Iliopoulos
- Division of Digestive Diseases, Center for Systems Biomedicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095; and
| | - Yatrik M Shah
- Division of Gastroenterology, Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109; Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Charalabos Pothoulakis
- Inflammatory Bowel Disease Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095;
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121
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Granger DN, Holm L, Kvietys P. The Gastrointestinal Circulation: Physiology and Pathophysiology. Compr Physiol 2016; 5:1541-83. [PMID: 26140727 DOI: 10.1002/cphy.c150007] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The gastrointestinal (GI) circulation receives a large fraction of cardiac output and this increases following ingestion of a meal. While blood flow regulation is not the intense phenomenon noted in other vascular beds, the combined responses of blood flow, and capillary oxygen exchange help ensure a level of tissue oxygenation that is commensurate with organ metabolism and function. This is evidenced in the vascular responses of the stomach to increased acid production and in intestine during periods of enhanced nutrient absorption. Complimenting the metabolic vasoregulation is a strong myogenic response that contributes to basal vascular tone and to the responses elicited by changes in intravascular pressure. The GI circulation also contributes to a mucosal defense mechanism that protects against excessive damage to the epithelial lining following ingestion of toxins and/or noxious agents. Profound reductions in GI blood flow are evidenced in certain physiological (strenuous exercise) and pathological (hemorrhage) conditions, while some disease states (e.g., chronic portal hypertension) are associated with a hyperdynamic circulation. The sacrificial nature of GI blood flow is essential for ensuring adequate perfusion of vital organs during periods of whole body stress. The restoration of blood flow (reperfusion) to GI organs following ischemia elicits an exaggerated tissue injury response that reflects the potential of this organ system to generate reactive oxygen species and to mount an inflammatory response. Human and animal studies of inflammatory bowel disease have also revealed a contribution of the vasculature to the initiation and perpetuation of the tissue inflammation and associated injury response.
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Affiliation(s)
- D Neil Granger
- Department of Molecular and Cellular Physiology, LSU Health Science Center-Shreveport, Shreveport, Louisiana, USA
| | - Lena Holm
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Peter Kvietys
- Department of Physiological Sciences, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
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122
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Flück K, Breves G, Fandrey J, Winning S. Hypoxia-inducible factor 1 in dendritic cells is crucial for the activation of protective regulatory T cells in murine colitis. Mucosal Immunol 2016; 9:379-90. [PMID: 26220168 DOI: 10.1038/mi.2015.67] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 06/23/2015] [Indexed: 02/04/2023]
Abstract
Dendritic cells (DCs) serve as a bridge between innate and adaptive immunity and help to maintain intestinal homeostasis. Inflammatory bowel disease (IBD) is associated with dysregulation of the mucosal immune response. The concomitant hypoxic inflammation in IBD will activate the transcription factor hypoxia-inducible factor-1 (HIF-1) to also drive gene expression in DCs. Recent studies have described a protective role for epithelial HIF-1 in mouse models of IBD. We investigated the role of HIF-1 in DC function in a dextran sodium sulfate (DSS)-induced model of murine colitis. Wild-type and dendritic cell-specific HIF-1α knockout mice were treated with 3% DSS for 7 days. Knockout of HIF-1α in DCs led to a significantly larger loss of body weight in mice with DSS-induced colitis than in control mice. Knockout mice exhibited more severe intestinal inflammation with increased levels of proinflammatory cytokines and enhanced production of mucin. Induction of regulatory T cells (Tregs) was impaired, and the number of forkhead box P3 (Foxp3) Tregs was diminished by dendritic HIF-1α knockout. Our findings demonstrate that in DCs HIF-1α is necessary for the induction of sufficient numbers of Tregs to control intestinal inflammation.
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Affiliation(s)
- K Flück
- Institut für Physiologie, Universität Duisburg-Essen, Essen, Germany.,Physiologisches Institut, Tierärztliche Hochschule Hannover, Hannover, Germany
| | - G Breves
- Physiologisches Institut, Tierärztliche Hochschule Hannover, Hannover, Germany
| | - J Fandrey
- Institut für Physiologie, Universität Duisburg-Essen, Essen, Germany
| | - S Winning
- Institut für Physiologie, Universität Duisburg-Essen, Essen, Germany
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123
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Transforming growth factor-β1 protects against intestinal epithelial barrier dysfunction caused by hypoxia-reoxygenation. Shock 2016; 43:483-9. [PMID: 25608140 DOI: 10.1097/shk.0000000000000333] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Intestinal epithelia regulate barrier integrity when challenged by inflammation, oxidative stress, and microbes. Transforming growth factor-β1 (TGF-β1) is a cytokine with known beneficial effects on intestinal epithelia, including barrier enhancement, after exposure to proinflammatory cytokines and infectious agents. The aim of this study was to determine whether TGF-β1 directly protects intestinal epithelia during hypoxia-reoxygenation (HR). Intestinal epithelial monolayers (T84, Caco-2) were exposed to either hypoxia (1% O2, 1 h) or oxidative stress (hydrogen peroxide, 1 mM), followed by normoxic atmosphere for different time points in the absence and presence of varying concentrations of TGF-β1. Transepithelial electrical resistance (TER) assessed barrier function, with RNA extracted for reverse transcription polymerase chain reaction analysis of GPx-1, HIF-1, heme-oxygenase-1 (HO-1), and NOX-1. In some experiments, intestinal epithelia were exposed to enterohemorrhagic Escherichia coli (EHEC) O157:H7 during the reoxygenation period and TER recorded 7 h after the infectious challenge. Hypoxia-reoxygenation significantly decreased TER in intestinal epithelia compared with normoxic controls. Transforming growth factor-β1 pretreatment ameliorated HR-induced epithelial barrier dysfunction in T84 (at 1 - 3 h) and Caco-2 (1 h) monolayers. Transforming growth factor-β1 preserved barrier integrity for up to 16 h after challenge with hydrogen peroxide. In TGF-β1-treated epithelial monolayers, only HO-1 mRNA significantly increased after HR (P < 0.05 vs. normoxic controls). The EHEC-induced epithelial barrier dysfunction was significantly worsened by intestinal HR (P < 0.05 vs. normoxia-EHEC-infected cells), but this was not protected by TGF-β1 pretreatment. Transforming growth factor-β1 preserves loss of epithelial barrier integrity caused by the stress of HR via a mechanism that may involve the upregulation of HO-1 transcription. Targeted treatment with TGF-β could lead to novel therapies in enteric diseases characterized by HR injury.
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Abstract
In this review, I summarize some of the recent insight into pharmacological targeting of hypoxia in disease models. Studies from cultured cell systems, animal models, and translation to human patients have revealed that posttranslational modifications of individual proteins within NF-κB and hypoxia-inducible factor pathways serve as ideal targets for analysis in disease models. Studies defining differences and similarities between these responses have taught us a number of important lessons about the complexity of the inflammatory response. A clearer definition of these pathways has provided new insight into disease pathogenesis and, importantly, the potential for new therapeutic targets.
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Abstract
Uncontrolled or non-resolving inflammation underpins a range of disease states including rheumatoid arthritis, inflammatory bowel disease and atherosclerosis. Hypoxia is a prominent feature of chronically inflamed tissues. This is due to elevated oxygen consumption by highly metabolically active inflamed resident cells and activated infiltrating immunocytes, as well as diminished oxygen supply due to vascular dysfunction. Tissue hypoxia can have a significant impact upon inflammatory signaling pathways in immune and non-immune cells and this can impact upon disease progression. In this review, we will discuss the relationship between tissue hypoxia and inflammation and identify how hypoxia-sensitive signaling pathways are potential therapeutic targets in chronic inflammatory disease.
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Affiliation(s)
- Eoin P Cummins
- School of Medicine and Medical Science & The Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Ciara E Keogh
- School of Medicine and Medical Science & The Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Daniel Crean
- School of Medicine and Medical Science & The Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Cormac T Taylor
- School of Medicine and Medical Science & The Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
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126
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Zeitouni NE, Dersch P, Naim HY, von Köckritz-Blickwede M. Hypoxia Decreases Invasin-Mediated Yersinia enterocolitica Internalization into Caco-2 Cells. PLoS One 2016; 11:e0146103. [PMID: 26731748 PMCID: PMC4701670 DOI: 10.1371/journal.pone.0146103] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/14/2015] [Indexed: 12/20/2022] Open
Abstract
Yersinia enterocolitica is a major cause of human yersiniosis, with enterocolitis being a typical manifestation. These bacteria can cross the intestinal mucosa, and invade eukaryotic cells by binding to host β1 integrins, a process mediated by the bacterial effector protein invasin. This study examines the role of hypoxia on the internalization of Y. enterocolitica into intestinal epithelial cells, since the gastrointestinal tract has been shown to be physiologically deficient in oxygen levels (hypoxic), especially in cases of infection and inflammation. We show that hypoxic pre-incubation of Caco-2 cells resulted in significantly decreased bacterial internalization compared to cells grown under normoxia. This phenotype was absent after functionally blocking host β1 integrins as well as upon infection with an invasin-deficient Y. enterocolitica strain. Furthermore, downstream phosphorylation of the focal adhesion kinase was also reduced under hypoxia after infection. In good correlation to these data, cells grown under hypoxia showed decreased protein levels of β1 integrins at the apical cell surface whereas the total protein level of the hypoxia inducible factor (HIF-1) alpha was elevated. Furthermore, treatment of cells with the HIF-1 α stabilizer dimethyloxalylglycine (DMOG) also reduced invasion and decreased β1 integrin protein levels compared to control cells, indicating a potential role for HIF-1α in this process. These results suggest that hypoxia decreases invasin-integrin-mediated internalization of Y. enterocolitica into intestinal epithelial cells by reducing cell surface localization of host β1 integrins.
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Affiliation(s)
- Nathalie E. Zeitouni
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Petra Dersch
- Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Hassan Y. Naim
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Maren von Köckritz-Blickwede
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Hannover, Germany
- * E-mail:
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127
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Abstract
Immune cells are highly dynamic in terms of their growth, proliferation, and effector functions as they respond to immunological challenges. Different immune cells can adopt distinct metabolic configurations that allow the cell to balance its requirements for energy, molecular biosynthesis, and longevity. However, in addition to facilitating immune cell responses, it is now becoming clear that cellular metabolism has direct roles in regulating immune cell function. This review article describes the distinct metabolic signatures of key immune cells, explains how these metabolic setups facilitate immune function, and discusses the emerging evidence that intracellular metabolism has an integral role in controlling immune responses.
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Affiliation(s)
| | - David K Finlay
- From the School of Biochemistry and Immunology and School of Pharmacy and Pharmaceutical Sciences, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
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128
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Tambuwala MM, Manresa MC, Cummins EP, Aversa V, Coulter IS, Taylor CT. Targeted delivery of the hydroxylase inhibitor DMOG provides enhanced efficacy with reduced systemic exposure in a murine model of colitis. J Control Release 2015; 217:221-7. [DOI: 10.1016/j.jconrel.2015.09.022] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/11/2015] [Accepted: 09/12/2015] [Indexed: 12/30/2022]
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129
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Zeitouni NE, Fandrey J, Naim HY, von Köckritz-Blickwede M. Measuring oxygen levels in Caco-2 cultures. HYPOXIA 2015; 3:53-66. [PMID: 27774482 PMCID: PMC5045089 DOI: 10.2147/hp.s85625] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE Measuring oxygen levels in three different systems of Caco-2 cell culture. METHODS Caco-2 cells were cultured in three different systems, using conventional polystyrene 24-well plates, special 24-well gas permeable plates, or on membrane inserts in conventional plates. Optical sensor spots were used to measure dissolved O2 levels in these cultured cells over the course of 6 days under normoxia (143 mmHg) and for 6 hours under hypoxia (7 mmHg). Western blot analysis was used to determine the protein levels of hypoxia-inducible factor 1α (HIF-1α) in the different cultures. RESULTS All culture systems displayed lower O2 levels over time than expected when cultured under normoxia conditions. On average, O2 levels reached as low as 25 mmHg in 24-well plates but remained at 97 and 117 mmHg in gas permeable plates and membrane inserts, respectively. Under hypoxia, 1 mL cell cultures equilibrated to 7 mmHg O2 within the first 60 minutes and dropped to 0.39 and 0.61 mmHg O2 in 24-well and gas permeable plates, respectively, after the 6-hour incubation period. Cultures in membrane inserts did not equilibrate to 7 mmHg by the end of the 6-hour incubation period, where the lowest O2 measurements reached 23.12 mmHg. Western blots of HIF-1α protein level in the whole cell lysates of the different Caco-2 cultures revealed distinct stabilization of HIF-1α after hypoxic incubation for 1, 2, and 4 hours in 24-well plates as well as gas permeable plates. For membrane inserts, notable HIF-1α was seen after 4 hours of hypoxic incubation. CONCLUSION Cellular oxygen depletion was achieved in different hypoxic Caco-2 culture systems. However, different oxygen levels comparing different culture systems indicate that O2 level should be carefully considered in oxygen-dependent experiments.
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Affiliation(s)
- Nathalie E Zeitouni
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover
| | - Joachim Fandrey
- Institute of Physiology, University Clinics Essen, University of Duisburg-Essen, Essen
| | - Hassan Y Naim
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover
| | - Maren von Köckritz-Blickwede
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover; Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine, Hannover, Germany
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130
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RhoB regulates the function of macrophages in the hypoxia-induced inflammatory response. Cell Mol Immunol 2015; 14:265-275. [PMID: 26388235 DOI: 10.1038/cmi.2015.78] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 07/17/2015] [Accepted: 07/19/2015] [Indexed: 12/11/2022] Open
Abstract
Immune cells, particularly macrophages, play critical roles in the hypoxia-induced inflammatory response. The small GTPase RhoB is usually rapidly induced by a variety of stimuli and has been described as an important regulator of cytoskeletal organization and vesicle and membrane receptor trafficking. However, it is unknown whether RhoB is involved in the hypoxia-induced inflammatory response. Here, we investigated the effect of hypoxia on the expression of RhoB and the mechanism and significance of RhoB expression in macrophages. We found that hypoxia significantly upregulated the expression of RhoB in RAW264.7 cells, mouse peritoneal macrophages, and the spleen of rats. Hypoxia-induced expression of RhoB was significantly blocked by a specific inhibitor of hypoxia-inducible factor-1α (HIF-1α), c-Jun N-terminal kinase (JNK), or extracellular-signal regulated protein kinase (ERK), indicating that hypoxia-activated HIF-1α, JNK, and ERK are involved in the upregulation of RhoB by hypoxia. Knockdown of RhoB expression not only significantly suppressed basal production of interleukin-1 beta (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α) in normoxia but also more markedly decreased the hypoxia-stimulated production of these cytokines. Furthermore, we showed that RhoB increased nuclear factor-kappa B (NF-κB) activity, and the inhibition of NF-κB transcriptional activity significantly decreased the RhoB-increased mRNA levels of IL-1β, IL-6, and TNF-α. Finally, we demonstrated that RhoB enhanced cell adhesion and inhibited cell migration in normoxia and hypoxia. Taken together, these results suggest that RhoB plays an important role in the hypoxia-induced activation of macrophages and the inflammatory response.Cellular & Molecular Immunology advance online publication, 21 September 2015; doi:10.1038/cmi.2015.78.
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Abstract
Hypoxia is a hallmark of chronically inflamed tissue. Hypoxia develops from vascular dysfunction and increased oxygen consumption by infiltrating leukocytes. With respect to inflammatory bowel disease (IBD), hypoxia is likely to be of particular importance: Impairment of the intestinal barrier during IBD allows anoxia from the lumen of the gut to spread to formerly normoxic tissue. In addition, disturbed perfusion of inflamed tissue and a higher oxygen demand of infiltrating immune cells lead to low oxygen levels in inflamed mucosal tissue. Here, cells become hypoxic and must now adapt to this condition. The hypoxia inducible factor (HIF)-1 complex is a key transcription factor for cellular adaption to low oxygen tension. HIF-1 is a heterodimer formed by two subunits: HIF-α (either HIF-1α or HIF-2α) and HIF-1β. Under normoxic conditions, hydroxylation of the HIF-α subunit by specific oxygen-dependent prolyl hydroxylases (PHDs) leads to ubiquitin proteasome-dependent degradation. Under hypoxic conditions, however, PHD activity is inhibited; thus, HIF-α can translocate into the nucleus, dimerize with HIF-1β, and bind to hypoxia-responsive elements of HIF-1 target genes. So far, most studies have addressed the function of HIF-1α in intestinal epithelial cells and the effect of HIF stabilization by PHD inhibitors in murine models of colitis. Furthermore, the role of HIF-1α in immune cells becomes more and more important as T cells or dendritic cells for which HIF-1 is of critical importance are highly involved in the pathogenesis of IBD. This review will summarize the function of HIF-1α and the therapeutic prospects for targeting the HIF pathway in intestinal mucosal inflammation.
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Affiliation(s)
- Katharina Flück
- Institut für Physiologie, Universität Duisburg-Essen, Essen, Germany
| | - Joachim Fandrey
- Institut für Physiologie, Universität Duisburg-Essen, Essen, Germany.
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132
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Collino M, Thiemermann C, Cerami A, Brines M. Flipping the molecular switch for innate protection and repair of tissues: Long-lasting effects of a non-erythropoietic small peptide engineered from erythropoietin. Pharmacol Ther 2015; 151:32-40. [DOI: 10.1016/j.pharmthera.2015.02.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 02/18/2015] [Indexed: 01/25/2023]
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133
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Nobili V, Alisi A, Cutrera R, Carpino G, De Stefanis C, D'Oria V, De Vito R, Cucchiara S, Gaudio E, Musso G. Altered gut-liver axis and hepatic adiponectin expression in OSAS: novel mediators of liver injury in paediatric non-alcoholic fatty liver. Thorax 2015; 70:769-81. [PMID: 26069285 DOI: 10.1136/thoraxjnl-2015-206782] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 05/26/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND Mechanism(s) connecting obstructive sleep apnoea syndrome (OSAS) to liver injury in paediatric non-alcoholic fatty liver disease (NAFLD) are unknown. We hypothesised alterations in gut-liver axis and in the pool and phenotype of hepatic progenitor cells (HPCs) may be involved in OSAS-associated liver injury in NAFLD. METHODS Eighty biopsy-proven NAFLD children (age, mean±SD, 11.4±2.0 years, 56% males, body mass index z-score 1.95±0.57) underwent a clinical-biochemical assessment, with measurement of insulin sensitivity, plasma cytokines, lipopolysaccharide (LPS), an intestinal permeability test and a standard polysomnography. Hepatic toll-like receptor (TLR)-4 expression by liver-resident cells and overall number and expression of resistin and adiponectin by HPCs were assessed by immunofluorescence and immunohistochemistry. OSAS was defined by an apnoea/hypopnoea index ≥1. RESULTS OSAS was characterised by an increased intestinal permeability and endotoxemia, coupled with TLR-4 upregulation in hepatocytes, Kupffer and hepatic stellate cells (HSCs) and by an expansion of an adiponectin-deficient HPC pool, key features of steatohepatitis and fibrosis.The duration of haemoglobin desaturation (SaO2 <90%) independently predicted intestinal permeability (β: 0.396; p=0.026), plasma LPS (β: 0.358; p=0.008) and TLR-4 expression by hepatocytes (β: 0.332; p=0.009), Kupffer cells (β: 0.357; p=0.006) and HSCs (β:0.445; p=0.002).SaO2 <90% predicted also HPC number (β: 0.471; p=0.001) and impaired adiponectin expression by HPC pool (β: -0.532; p=0.0009).These relationships were observed in obese and non-obese children. CONCLUSIONS In paediatric NAFLD, OSAS is associated with increased endotoxemia coupled with impaired gut barrier function, with increased TLR-4-mediated hepatic susceptibility to endotoxemia and with an expansion of an adiponectin-deficient HPC pool. These alterations may represent a novel pathogenic link and a potential therapeutic target for OSAS-associated liver injury in NAFLD.
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Affiliation(s)
- Valerio Nobili
- Hepato-Metabolic Disease Unit, "Bambino Gesù" Children's Hospital, IRCCS, Rome, Italy
| | - Anna Alisi
- Liver Research Unit, "Bambino Gesù" Children's Hospital, IRCCS, Rome, Italy
| | - Renato Cutrera
- Pneumology Unit-Sleep and NIV Laboratory, "Bambino Gesù" Children's Hospital, IRCCS, Rome, Italy
| | - Guido Carpino
- Department of Movement, Human and Health Sciences, Division of Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | | | - Valentina D'Oria
- Confocal Microscopy Unit, "Bambino Gesù" Children's Hospital, IRCCS, Rome, Italy
| | - Rita De Vito
- Pathology Unit, "Bambino Gesù" Children's Hospital, IRCCS, Rome, Italy
| | - Salvatore Cucchiara
- Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, Sapienza University of Rome, Rome, Italy
| | - Eugenio Gaudio
- Pediatric Gastroenterology and Liver Unit, Department of Pediatrics, Sapienza University, Rome, Italy
| | - Giovanni Musso
- Gradenigo Hospital C.so Regina Margherita 8, Turin, Italy
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Sun L, Xu C, Chen G, Yu M, Yang S, Qiu Y, Peng K, Wang W, Xiao W, Yang H. A Novel Role of OS-9 in the Maintenance of Intestinal Barrier Function from Hypoxia-induced Injury via p38-dependent Pathway. Int J Biol Sci 2015; 11:664-71. [PMID: 25999789 PMCID: PMC4440256 DOI: 10.7150/ijbs.10783] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 02/18/2015] [Indexed: 12/11/2022] Open
Abstract
OS-9 is a lectin required for efficient ubquitination of glycosylated substrates of endoplasmic reticulum-associated degradation (ERAD). OS-9 has previously been implicated in ER-to-Golgi transport and transcription factor turnover. However, we know very little about other functions of OS-9 under endoplasmic reticulum stress. Here, we used gene knockdown and overexpression approaches to study the protective effect of OS-9 on intestinal barrier function of intestinal epithelial cell Caco-2 monolayer. We found that OS-9 attenuated intestinal epithelial barrier dysfunction under hypoxia through up-regulating occludin and claudin-1 protein expression. Furthermore, we showed that the up-regulation of occludin and claudin-1 induced by OS-9 was mediated by p38 and ERK1/2 phosphorylation and did not involve HIF-1α. In summary, our results demonstrate that OS-9 up-regulates occludin and claudin-1 by activating the MAP kinase (MAPK) pathway, and thus protects the epithelial barrier function of Caco-2 monolayer under hypoxia condition.
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Affiliation(s)
- Lihua Sun
- Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Chao Xu
- Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Guoqing Chen
- Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Min Yu
- Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Songwei Yang
- Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Yuan Qiu
- Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Ke Peng
- Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Wensheng Wang
- Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Weidong Xiao
- Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Hua Yang
- Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, China
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Parra RS, Lopes AH, Carreira EU, Feitosa MR, Cunha FQ, Garcia SB, Cunha TM, da Rocha JJR, Féres O. Hyperbaric oxygen therapy ameliorates TNBS-induced acute distal colitis in rats. Med Gas Res 2015; 5:6. [PMID: 25926972 PMCID: PMC4414439 DOI: 10.1186/s13618-015-0026-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 04/06/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND This study investigated the therapeutic effects of hyperbaric oxygen in experimental acute distal colitis focusing on its effect on the production of pro-inflammatory cytokines, nitric oxide and hypoxia-inducible factor 1alpha. METHODS Colitis was induced with a rectal infusion of 150 mg/kg of TNBS under anesthesia with Ketamine (50 mg/kg) and Xylazine (10 mg/kg). Control animals received only rectal saline. After colitis induction, animals were subjected to two sessions of hyperbaric oxygen and were then euthanized. The distal intestine was resected for macroscopic analysis, determination of myeloperoxidase activity, western-blotting analyses of inducible nitric oxide synthase and cyclooxygenase-2 expression and immunohistochemical analysis of hypoxia-inducible factor 1alpha and cyclooxygenase-2. Cytokines levels in the distal intestine were measured using an enzyme-linked immunosorbent assay. RESULTS Hyperbaric oxygen therapy attenuated the severity of acute distal colitis, with reduced macroscopic damage score. This effect was associated with prevention in the increase of pro-inflammatory cytokine production; myeloperoxidase activity, in the expression of inducible nitric oxide synthase and cyclooxygenase-2. Finally, hyperbaric oxygen inhibited the acute distal colitis-induced up-regulation of hypoxia-inducible factor 1alpha. CONCLUSIONS The results indicate that hyperbaric oxygen attenuates the severity of acute distal colitis through the down-regulation of pro-inflammatory events.
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Affiliation(s)
- Rogério S Parra
- />Division of Coloproctology, Department of Surgery and Anatomy. Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Alexandre H Lopes
- />Department of Pharmacology, Ribeirão Preto Medical School, University of Sao Paulo, Ribeirão Preto, SP Brazil
| | - Eleonora U Carreira
- />Department of Pharmacology, Ribeirão Preto Medical School, University of Sao Paulo, Ribeirão Preto, SP Brazil
| | - Marley R Feitosa
- />Division of Coloproctology, Department of Surgery and Anatomy. Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Fernando Q Cunha
- />Department of Pharmacology, Ribeirão Preto Medical School, University of Sao Paulo, Ribeirão Preto, SP Brazil
| | - Sérgio B Garcia
- />Department of Pathology, Ribeirão Preto Medical School, University of Sao Paulo, Ribeirão Preto, SP Brazil
| | - Thiago M Cunha
- />Department of Pharmacology, Ribeirão Preto Medical School, University of Sao Paulo, Ribeirão Preto, SP Brazil
| | - José J R da Rocha
- />Division of Coloproctology, Department of Surgery and Anatomy. Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP Brazil
| | - Omar Féres
- />Division of Coloproctology, Department of Surgery and Anatomy. Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP Brazil
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136
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Colgan SP, Curtis VF, Lanis JM, Glover LE. Metabolic regulation of intestinal epithelial barrier during inflammation. Tissue Barriers 2015; 3:e970936. [PMID: 25838978 DOI: 10.4161/21688362.2014.970936] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/25/2014] [Indexed: 12/21/2022] Open
Abstract
The gastrointestinal mucosa has proven to be an interesting tissue for which to investigate disease-related metabolism. In this review, we outline some evidence that implicates metabolic signaling as important features of barrier in the healthy and disease. Studies from cultured cell systems, animal models and human patients have revealed that metabolites generated within the inflammatory microenvironment are central to barrier regulation. These studies have revealed a prominent role for hypoxia and hypoxia-inducible factor (HIF) at key steps in adenine nucleotide metabolism and within the creatine kinase pathway. Results from animal models of intestinal inflammation have demonstrated an almost uniformly beneficial influence of HIF stabilization on disease outcomes and barrier function. Studies underway to elucidate the contribution of immune responses will provide additional insight into how metabolic changes contribute to the complexity of the gastrointestinal tract and how such information might be harnessed for therapeutic benefit.
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Key Words
- AMP, adenosine monophosphate
- CK, creatine kinase
- ChIP, chromatin immunoprecipitation
- Colitis
- HIF, hypoxia-inducible factor
- PHD, prolyl hydroxylase
- PMN, polymorphonuclear leukcoyte, neutrophil
- TJ, tight junction
- VASP, vasodilator-stimulated
- ZO-1, zonula occludens-1
- creatine
- epithelium
- inflammation
- metabolism
- mucosa
- murine model
- neutrophil
- nucleoside
- nucleotidase
- nucleotide
- phosphocreatine
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Affiliation(s)
- Sean P Colgan
- Departments of Medicine and the Mucosal Inflammation Program; University of Colorado School of Medicine ; Aurora, CO USA
| | - Valerie F Curtis
- Departments of Medicine and the Mucosal Inflammation Program; University of Colorado School of Medicine ; Aurora, CO USA
| | - Jordi M Lanis
- Departments of Medicine and the Mucosal Inflammation Program; University of Colorado School of Medicine ; Aurora, CO USA
| | - Louise E Glover
- Departments of Medicine and the Mucosal Inflammation Program; University of Colorado School of Medicine ; Aurora, CO USA
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137
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Neutrophils and inflammatory resolution in the mucosa. Semin Immunol 2015; 27:177-83. [PMID: 25818531 DOI: 10.1016/j.smim.2015.03.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 03/10/2015] [Accepted: 03/11/2015] [Indexed: 12/13/2022]
Abstract
Inflammatory diseases in mucosal organs as diverse as the lung, liver and intestine inevitably require the intimate interactions between neutrophils and epithelia. The physiologic consequences of such interactions often determine endpoint organ function, and for this reason, much recent interest has developed in identifying mechanisms and novel targets to promote the resolution of mucosal inflammation. Physiologically-relevant in vitro and in vivo model systems have aided in discovery of novel pathways to define basic inflammatory mechanisms and approaches to defining the concepts of inflammatory resolution. Here, we will review the recent literature regarding the contribution of neutrophils to inflammatory resolution, with an emphasis on the role of the tissue microenvironment, endogenous pathways for promoting resolution and the molecular determinants of neutrophil-epithelial cell interactions during ongoing inflammation. These recent studies highlight the dynamic nature of pro-resolving pathways and lend insight into the complexity of treating mucosal inflammation.
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138
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Sequeira IR, Kruger MC, Hurst RD, Lentle RG. Ascorbic Acid may Exacerbate Aspirin-Induced Increase in Intestinal Permeability. Basic Clin Pharmacol Toxicol 2015; 117:195-203. [PMID: 25641731 DOI: 10.1111/bcpt.12388] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 01/20/2015] [Indexed: 12/23/2022]
Abstract
Ascorbic acid in combination with aspirin has been used to prevent aspirin-induced oxidative GI damage. We aimed to determine whether ascorbic acid reduces or prevents aspirin-induced changes in intestinal permeability over a 6-hr period using saccharidic probes mannitol and lactulose. The effects of administration of 600 mg aspirin alone, 500 mg ascorbic acid alone and simultaneous dosage of both agents were compared in a cross-over study in 28 healthy female volunteers. These effects were also compared with that of a placebo. The ability of ascorbic acid to mitigate the effects of aspirin when administered either half an hour before or after dosage with aspirin was also assessed in 19 healthy female volunteers. The excretion of lactulose over the 6-hr period was augmented after consumption of either aspirin or ascorbic acid compared with that after consumption of placebo. Dosage with ascorbic acid alone augmented the excretion of lactulose more than did aspirin alone. Simultaneous dosage with both agents augmented the excretion of lactulose in an additive manner. The timing of dosage with ascorbic acid in relation to that with aspirin had no significant effect on the excretion of the two sugars. These findings indicate that ascorbic acid does not prevent aspirin-induced increase in gut permeability rather that both agents augment it to a similar extent. The additive effect on simultaneous dosage with both agents in augmenting the absorption of lactulose suggests that each influences paracellular permeability by different pathways.
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Affiliation(s)
- Ivana R Sequeira
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | - Marlena C Kruger
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | - Roger D Hurst
- The New Zealand Institute for Plant and Food Research Limited, Palmerston North, New Zealand
| | - Roger G Lentle
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
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139
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Campbell EL, Colgan SP. Neutrophils and inflammatory metabolism in antimicrobial functions of the mucosa. J Leukoc Biol 2015; 98:517-22. [PMID: 25714801 DOI: 10.1189/jlb.3mr1114-556r] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 01/22/2015] [Indexed: 01/29/2023] Open
Abstract
In this mini-review, we will discuss recent findings that implicate neutrophil infiltration and function in establishing a metabolic environment to facilitate efficient pathogen clearance. For decades, neutrophils have been regarded as short lived, nonspecific granulocytes, equipped with toxic antimicrobial factors and a respiratory burst generating ROS. Recent findings demonstrate the importance of HIF signaling in leukocytes and surrounding tissues during inflammation. Here, we will review the potential mechanisms and outcomes of HIF stabilization within the intestinal mucosa.
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Affiliation(s)
- Eric L Campbell
- Mucosal Inflammation Program, Division of Gastroenterology and Hepatology and Departments of Medicine and Immunology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Sean P Colgan
- Mucosal Inflammation Program, Division of Gastroenterology and Hepatology and Departments of Medicine and Immunology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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140
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Harnoss JM, Strowitzki MJ, Radhakrishnan P, Platzer LK, Harnoss JC, Hank T, Cai J, Ulrich A, Schneider M. Therapeutic inhibition of prolyl hydroxylase domain-containing enzymes in surgery: putative applications and challenges. HYPOXIA 2015; 3:1-14. [PMID: 27774478 PMCID: PMC5045068 DOI: 10.2147/hp.s60872] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Oxygen is essential for metazoans to generate energy. Upon oxygen deprivation adaptive and protective pathways are induced, mediated by hypoxia-inducible factors (HIFs) and prolyl hydroxylase domain-containing enzymes (PHDs). Both play a pivotal role in various conditions associated with prolonged ischemia and inflammation, and are promising targets for therapeutic intervention. This review focuses on aspects of therapeutic PHD modulation in surgically relevant disease conditions such as hepatic and intestinal disorders, wound healing, innate immune responses, and tumorigenesis, and discusses the therapeutic potential and challenges of PHD inhibition in surgical patients.
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Affiliation(s)
- Jonathan Michael Harnoss
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Moritz Johannes Strowitzki
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Praveen Radhakrishnan
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Lisa Katharina Platzer
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Julian Camill Harnoss
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Thomas Hank
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Jun Cai
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Alexis Ulrich
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Martin Schneider
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
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141
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Gonzalez LM, Moeser AJ, Blikslager AT. Animal models of ischemia-reperfusion-induced intestinal injury: progress and promise for translational research. Am J Physiol Gastrointest Liver Physiol 2015; 308:G63-75. [PMID: 25414098 PMCID: PMC4297854 DOI: 10.1152/ajpgi.00112.2013] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Research in the field of ischemia-reperfusion injury continues to be plagued by the inability to translate research findings to clinically useful therapies. This may in part relate to the complexity of disease processes that result in intestinal ischemia but may also result from inappropriate research model selection. Research animal models have been integral to the study of ischemia-reperfusion-induced intestinal injury. However, the clinical conditions that compromise intestinal blood flow in clinical patients ranges widely from primary intestinal disease to processes secondary to distant organ failure and generalized systemic disease. Thus models that closely resemble human pathology in clinical conditions as disparate as volvulus, shock, and necrotizing enterocolitis are likely to give the greatest opportunity to understand mechanisms of ischemia that may ultimately translate to patient care. Furthermore, conditions that result in varying levels of ischemia may be further complicated by the reperfusion of blood to tissues that, in some cases, further exacerbates injury. This review assesses animal models of ischemia-reperfusion injury as well as the knowledge that has been derived from each to aid selection of appropriate research models. In addition, a discussion of the future of intestinal ischemia-reperfusion research is provided to place some context on the areas likely to provide the greatest benefit from continued research of ischemia-reperfusion injury.
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Affiliation(s)
- Liara M. Gonzalez
- 1Department of Clinical Sciences, Center for Comparative Medicine and Translational Research, North Carolina State University, Raleigh, North Carolina; and
| | - Adam J. Moeser
- 2Department of Population Health and Pathobiology, Center for Comparative Medicine and Translational Research, North Carolina State University, Raleigh, North Carolina
| | - Anthony T. Blikslager
- 1Department of Clinical Sciences, Center for Comparative Medicine and Translational Research, North Carolina State University, Raleigh, North Carolina; and
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142
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Kumar V, Gabrilovich DI. Hypoxia-inducible factors in regulation of immune responses in tumour microenvironment. Immunology 2015; 143:512-9. [PMID: 25196648 DOI: 10.1111/imm.12380] [Citation(s) in RCA: 248] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 08/21/2014] [Accepted: 08/29/2014] [Indexed: 12/14/2022] Open
Abstract
Hypoxia is one of the hallmarks of the tumour microenvironment. It is the result of insufficient blood supply to support proliferating tumour cells. In response to hypoxia, the cellular machinery uses mechanisms whereby the low level of oxygen is sensed and counterbalanced by changing the transcription of numerous genes. Hypoxia-inducible factors (HIF) play a critical role in the regulation of cellular responses to hypoxia. In recent years ample evidence has indicated that HIF play a prominent role in tumour immune responses. Up-regulation of HIF1α promotes immune suppressive activity of myeloid-derived suppressive cells (MDSC) and tumour-associated macrophages (TAM) and rapid differentiation of MDSC to TAM. HIF1α does not affect MDSC differentiation to dendritic cells (DC) but instead causes DC activation. HIF inhibit effector functions of tumour-infiltrating lymphocytes. HIF1α inhibits regulatory T (Treg) cell development by switching the balance towards T helper type 17 cells. However, as a major part of Treg cell differentiation does not take place in the tumour site, a functionally more important role of HIF1α is in the promotion of Treg cell recruitment to the tumour site in response to chemokines. As a result, the presence of Treg cells inside tumours is increased. Hence, HIF play a largely negative role in the regulation of immune responses inside tumours. It appears that therapeutic strategies targeting HIF in the immune system could be beneficial for anti-tumour immune responses.
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143
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Taniguchi CM, Miao YR, Diep AN, Wu C, Rankin EB, Atwood TF, Xing L, Giaccia AJ. PHD inhibition mitigates and protects against radiation-induced gastrointestinal toxicity via HIF2. Sci Transl Med 2014; 6:236ra64. [PMID: 24828078 DOI: 10.1126/scitranslmed.3008523] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Radiation-induced gastrointestinal (GI) toxicity can be a major source of morbidity and mortality after radiation exposure. There is an unmet need for effective preventative or mitigative treatments against the potentially fatal diarrhea and water loss induced by radiation damage to the GI tract. We report that prolyl hydroxylase inhibition by genetic knockout or pharmacologic inhibition of all PHD (prolyl hydroxylase domain) isoforms by the small-molecule dimethyloxallyl glycine (DMOG) increases hypoxia-inducible factor (HIF) expression, improves epithelial integrity, reduces apoptosis, and increases intestinal angiogenesis, all of which are essential for radioprotection. HIF2, but not HIF1, is both necessary and sufficient to prevent radiation-induced GI toxicity and death. Increased vascular endothelial growth factor (VEGF) expression contributes to the protective effects of HIF2, because inhibition of VEGF function reversed the radioprotection and radiomitigation afforded by DMOG. Additionally, mortality from abdominal or total body irradiation was reduced even when DMOG was given 24 hours after exposure. Thus, prolyl hydroxylase inhibition represents a treatment strategy to protect against and mitigate GI toxicity from both therapeutic radiation and potentially lethal radiation exposures.
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Affiliation(s)
- Cullen M Taniguchi
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Yu Rebecca Miao
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Anh N Diep
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Colleen Wu
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Erinn B Rankin
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Todd F Atwood
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Lei Xing
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA
| | - Amato J Giaccia
- Department of Radiation Oncology, Stanford University, Stanford, CA 94305, USA.
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144
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Moreno-Indias I, Torres M, Montserrat JM, Sanchez-Alcoholado L, Cardona F, Tinahones FJ, Gozal D, Poroyko VA, Navajas D, Queipo-Ortuño MI, Farré R. Intermittent hypoxia alters gut microbiota diversity in a mouse model of sleep apnoea. Eur Respir J 2014; 45:1055-65. [PMID: 25537565 DOI: 10.1183/09031936.00184314] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We assessed whether intermittent hypoxia, which emulates one of the hallmarks of obstructive sleep apnoea (OSA), leads to altered faecal microbiome in a murine model. In vivo partial pressure of oxygen was measured in colonic faeces during intermittent hypoxia in four anesthetised mice. 10 mice were subjected to a pattern of chronic intermittent hypoxia (20 s at 5% O2 and 40 s at room air for 6 h·day(-1)) for 6 weeks and 10 mice served as normoxic controls. Faecal samples were obtained and microbiome composition was determined by 16S rRNA pyrosequencing and bioinformatic analysis by Quantitative Insights into Microbial Ecology. Intermittent hypoxia exposures translated into hypoxia/re-oxygenation patterns in the faeces proximal to the bowel epithelium (<200 μm). A significant effect of intermittent hypoxia on global microbial community structure was found. Intermittent hypoxia increased the α-diversity (Shannon index, p<0.05) and induced a change in the gut microbiota (ANOSIM analysis of β-diversity, p<0.05). Specifically, intermittent hypoxia-exposed mice showed a higher abundance of Firmicutes and a smaller abundance of Bacteroidetes and Proteobacteria phyla than controls. Faecal microbiota composition and diversity are altered as a result of intermittent hypoxia realistically mimicking OSA, suggesting the possibility that physiological interplays between host and gut microbiota could be deregulated in OSA.
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Affiliation(s)
- Isabel Moreno-Indias
- Unidad de Gestión Clínica de Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain. Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBER), Madrid, Spain. These authors contributed equally
| | - Marta Torres
- Laboratori del Son, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain. Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, CIBER, Madrid, Spain. These authors contributed equally
| | - Josep M Montserrat
- Laboratori del Son, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain. Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, CIBER, Madrid, Spain. Institut Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
| | - Lidia Sanchez-Alcoholado
- Unidad de Gestión Clínica de Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain. Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBER), Madrid, Spain
| | - Fernando Cardona
- Unidad de Gestión Clínica de Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain. Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBER), Madrid, Spain
| | - Francisco J Tinahones
- Unidad de Gestión Clínica de Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain. Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBER), Madrid, Spain
| | - David Gozal
- Section of Pediatric Sleep Medicine, Dept of Pediatrics, Pritzker School of Medicine, The University of Chicago, Chicago, IL, USA
| | - Valeryi A Poroyko
- Section of Pediatric Sleep Medicine, Dept of Pediatrics, Pritzker School of Medicine, The University of Chicago, Chicago, IL, USA
| | - Daniel Navajas
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, CIBER, Madrid, Spain. Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona, Spain. Institut Bioenginyeria de Catalunya, Barcelona, Spain
| | - Maria I Queipo-Ortuño
- Unidad de Gestión Clínica de Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain. Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBER), Madrid, Spain.
| | - Ramon Farré
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, CIBER, Madrid, Spain. Institut Investigacions Biomediques August Pi Sunyer, Barcelona, Spain. Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona, Spain
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145
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Ravcheev DA, Thiele I. Systematic genomic analysis reveals the complementary aerobic and anaerobic respiration capacities of the human gut microbiota. Front Microbiol 2014; 5:674. [PMID: 25538694 PMCID: PMC4257093 DOI: 10.3389/fmicb.2014.00674] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 11/19/2014] [Indexed: 11/13/2022] Open
Abstract
Because of the specific anatomical and physiological properties of the human intestine, a specific oxygen gradient builds up within this organ that influences the intestinal microbiota. The intestinal microbiome has been intensively studied in recent years, and certain respiratory substrates used by gut inhabiting microbes have been shown to play a crucial role in human health. Unfortunately, a systematic analysis has not been previously performed to determine the respiratory capabilities of human gut microbes (HGM). Here, we analyzed the distribution of aerobic and anaerobic respiratory reductases in 254 HGM genomes. In addition to the annotation of known enzymes, we also predicted a novel microaerobic reductase and novel thiosulfate reductase. Based on this comprehensive assessment of respiratory reductases in the HGM, we proposed a number of exchange pathways among different bacteria involved in the reduction of various nitrogen oxides. The results significantly expanded our knowledge of HGM metabolism and interactions in bacterial communities.
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Affiliation(s)
- Dmitry A Ravcheev
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg Esch-sur-Alzette, Luxembourg ; Division 6: Comparative Genomics of Regulation System, A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences Moscow, Russia
| | - Ines Thiele
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg Esch-sur-Alzette, Luxembourg
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146
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Eltzschig HK, Bratton DL, Colgan SP. Targeting hypoxia signalling for the treatment of ischaemic and inflammatory diseases. Nat Rev Drug Discov 2014; 13:852-69. [PMID: 25359381 PMCID: PMC4259899 DOI: 10.1038/nrd4422] [Citation(s) in RCA: 260] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hypoxia-inducible factors (HIFs) are stabilized during adverse inflammatory processes associated with disorders such as inflammatory bowel disease, pathogen infection and acute lung injury, as well as during ischaemia-reperfusion injury. HIF stabilization and hypoxia-induced changes in gene expression have a profound impact on the inflamed tissue microenvironment and on disease outcomes. Although the mechanism that initiates HIF stabilization may vary, the final molecular steps that control HIF stabilization converge on a set of oxygen-sensing prolyl hydroxylases (PHDs) that mark HIFs for proteasomal degradation. PHDs are therefore promising therapeutic targets. In this Review, we discuss the emerging potential and associated challenges of targeting the PHD-HIF pathway for the treatment of inflammatory and ischaemic diseases.
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Affiliation(s)
- Holger K Eltzschig
- Organ Protection Program, Department of Anesthesiology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Donna L Bratton
- Department of Pediatrics, National Jewish Health, Denver, Colorado 80206, USA
| | - Sean P Colgan
- Mucosal Inflammation Program, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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147
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Manresa MC, Godson C, Taylor CT. Hypoxia-sensitive pathways in inflammation-driven fibrosis. Am J Physiol Regul Integr Comp Physiol 2014; 307:R1369-80. [PMID: 25298511 DOI: 10.1152/ajpregu.00349.2014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Tissue injury can occur for a variety of reasons, including physical damage, infection, and ischemia. The ability of tissues to effectively recover from injury is a cornerstone of human health. The healing response in tissues is conserved across organs and typically involves distinct but overlapping inflammatory, proliferative, and maturation/resolution phases. If the inflammatory phase is not successfully controlled and appropriately resolved, an excessive healing response characterized by scar formation can lead to tissue fibrosis, a major clinical complication in disorders such as Crohn's disease (CD). As a result of enhanced metabolic and inflammatory processes during chronic inflammation, profound changes in tissue oxygen levels occur leading to localized tissue hypoxia. Therefore, inflammation, fibrosis, and hypoxia are coincidental events during inflammation-driven fibrosis. Our current understanding of the mechanism(s) underpinning fibrosis is limited as are the therapeutic options available. In this review, we discuss what is known about the cellular and molecular mechanisms underpinning inflammation-driven fibrosis and how hypoxia may play a role in shaping this process.
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Affiliation(s)
- Mario C Manresa
- School of Medicine and Medical Science and the Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Catherine Godson
- School of Medicine and Medical Science and the Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Cormac T Taylor
- School of Medicine and Medical Science and the Conway Institute, University College Dublin, Belfield, Dublin, Ireland
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148
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Ward JBJ, Keely SJ, Keely SJ. Oxygen in the regulation of intestinal epithelial transport. J Physiol 2014; 592:2473-89. [PMID: 24710059 DOI: 10.1113/jphysiol.2013.270249] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The transport of fluid, nutrients and electrolytes to and from the intestinal lumen is a primary function of epithelial cells. Normally, the intestine absorbs approximately 9 l of fluid and 1 kg of nutrients daily, driven by epithelial transport processes that consume large amounts of cellular energy and O2. The epithelium exists at the interface of the richly vascularised mucosa, and the anoxic luminal environment and this steep O2 gradient play a key role in determining the expression pattern of proteins involved in fluid, nutrient and electrolyte transport. However, the dynamic nature of the splanchnic circulation necessitates that the epithelium can evoke co-ordinated responses to fluctuations in O2 availability, which occur either as a part of the normal digestive process or as a consequence of several pathophysiological conditions. While it is known that hypoxia-responsive signals, such as reactive oxygen species, AMP-activated kinase, hypoxia-inducible factors, and prolyl hydroxylases are all important in regulating epithelial responses to altered O2 supply, our understanding of the molecular mechanisms involved is still limited. Here, we aim to review the current literature regarding the role that O2 plays in regulating intestinal transport processes and to highlight areas of research that still need to be addressed.
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Affiliation(s)
- Joseph B J Ward
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Simon J Keely
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle NSW, Australia
| | - Stephen J Keely
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
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149
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Negative regulation of Hif1a expression and TH17 differentiation by the hypoxia-regulated microRNA miR-210. Nat Immunol 2014; 15:393-401. [PMID: 24608041 PMCID: PMC3996831 DOI: 10.1038/ni.2846] [Citation(s) in RCA: 193] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 02/12/2014] [Indexed: 02/07/2023]
Abstract
MicroRNA-210 (miR-210) is a signature microRNA of hypoxia. We found robust increase (>100-fold) of miR-210 abundance in activated T cells, especially in the TH17 lineage. Hypoxia synergized with T cell receptor (TCR)–CD28 stimulation to accelerate and increase the magnitude of Mir210 expression. Mir210 was directly regulated by HIF-1α, a key regulator of TH17 polarization. Surprisingly, Hif1a was identified as a miR-210-target, suggesting negative-feedback by miR-210 to inhibit HIF-1α protein expression. Deletion of Mir210 promoted TH17 differentiation under conditions with limited oxygen. In experimental colitis, miR-210 reduced Hif1a transcript abundance, reduced the proportion of cells producing inflammatory cytokines and controlled disease severity. Our study identifies miR-210 as an important regulator of T cell differentiation in hypoxia, which can limit immunopathology.
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150
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Eckle T, Kewley EM, Brodsky KS, Tak E, Bonney S, Gobel M, Anderson D, Glover LE, Riegel AK, Colgan SP, Eltzschig HK. Identification of hypoxia-inducible factor HIF-1A as transcriptional regulator of the A2B adenosine receptor during acute lung injury. THE JOURNAL OF IMMUNOLOGY 2014; 192:1249-56. [PMID: 24391213 DOI: 10.4049/jimmunol.1100593] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Although acute lung injury (ALI) contributes significantly to critical illness, resolution often occurs spontaneously through endogenous pathways. We recently found that mechanical ventilation increases levels of pulmonary adenosine, a signaling molecule known to attenuate lung inflammation. In this study, we hypothesized a contribution of transcriptionally controlled pathways to pulmonary adenosine receptor (ADOR) signaling during ALI. We gained initial insight from microarray analysis of pulmonary epithelia exposed to conditions of cyclic mechanical stretch, a mimic for ventilation-induced lung disease. Surprisingly, these studies revealed a selective induction of the ADORA2B. Using real-time RT-PCR and Western blotting, we confirmed an up to 9-fold induction of the ADORA2B following cyclic mechanical stretch (A549, Calu-3, or human primary alveolar epithelial cells). Studies using ADORA2B promoter constructs identified a prominent region within the ADORA2B promoter conveying stretch responsiveness. This region of the promoter contained a binding site for the transcription factor hypoxia-inducible factor (HIF)-1. Additional studies using site-directed mutagenesis or transcription factor binding assays demonstrated a functional role for HIF-1 in stretch-induced increases of ADORA2B expression. Moreover, studies of ventilator-induced lung injury revealed induction of the ADORA2B during ALI in vivo that was abolished following HIF inhibition or genetic deletion of Hif1a. Together, these studies implicate HIF in the transcriptional control of pulmonary adenosine signaling during ALI.
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Affiliation(s)
- Tobias Eckle
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado, Aurora, CO 80045
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