201
|
Kannan KB, Colorado I, Reino D, Palange D, Lu Q, Qin X, Abungu B, Watkins A, Caputo FJ, Xu DZ, Semenza GL, Deitch EA, Feinman R. Hypoxia-inducible factor plays a gut-injurious role in intestinal ischemia reperfusion injury. Am J Physiol Gastrointest Liver Physiol 2011; 300:G853-61. [PMID: 21183660 PMCID: PMC3094138 DOI: 10.1152/ajpgi.00459.2010] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gut injury and loss of normal intestinal barrier function are key elements in the paradigm of gut-origin systemic inflammatory response syndrome, acute lung injury, and multiple organ dysfunction syndrome (MODS). As hypoxia-inducible factor (HIF-1) is a critical determinant of the physiological and pathophysiological response to hypoxia and ischemia, we asked whether HIF-1 plays a proximal role in the induction of gut injury and subsequent lung injury. Using partially HIF-1α-deficient mice in an isolated superior mesenteric artery occlusion (SMAO) intestinal ischemia reperfusion (I/R) injury model (45 min SMAO followed by 3 h of reperfusion), we showed a direct relationship between HIF-1 activation and intestinal I/R injury. Specifically, partial HIF-1α deficiency attenuated SMAO-induced increases in intestinal permeability, lipid peroxidation, mucosal caspase-3 activity, and IL-1β mRNA levels. Furthermore, partial HIF-1α deficiency prevented the induction of ileal mucosal inducible nitric oxide synthase (iNOS) protein levels after SMAO and iNOS deficiency ameliorated SMAO-induced villus injury. Resistance to SMAO-induced gut injury was also associated with resistance to lung injury, as reflected by decreased levels of myeloperoxidase, IL-6 and IL-10 in the lungs of HIF-1α(+/-) mice. In contrast, a short duration of SMAO (15 min) followed by 3 h of reperfusion neither induced mucosal HIF-1α protein levels nor caused significant gut and lung injury in wild-type or HIF-1α(+/-) mice. This study indicates that intestinal HIF-1 activation is a proximal regulator of I/R-induced gut mucosal injury and gut-induced lung injury. However, the duration and severity of the gut I/R insult dictate whether HIF-1 plays a gut-protective or deleterious role.
Collapse
Affiliation(s)
- Kolenkode B. Kannan
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| | - Iriana Colorado
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| | - Diego Reino
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| | - David Palange
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| | - Qi Lu
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| | - Xiaofa Qin
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| | - Billy Abungu
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| | - Anthony Watkins
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| | - Francis J. Caputo
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| | - Da-Zhong Xu
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| | - Gregg L. Semenza
- 2Vascular Program, Institute for Cell Engineering, and McKusick-Nathans Institute of Genetic Medicine, John Hopkins University School of Medicine, Baltimore, Maryland
| | - Edwin A. Deitch
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| | - Rena Feinman
- 1Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey; and
| |
Collapse
|
202
|
Kominsky DJ, Keely S, MacManus CF, Glover LE, Scully M, Collins CB, Bowers BE, Campbell EL, Colgan SP. An endogenously anti-inflammatory role for methylation in mucosal inflammation identified through metabolite profiling. THE JOURNAL OF IMMUNOLOGY 2011; 186:6505-14. [PMID: 21515785 DOI: 10.4049/jimmunol.1002805] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Tissues of the mucosa are lined by an epithelium that provides barrier and transport functions. It is now appreciated that inflammatory responses in inflammatory bowel diseases are accompanied by striking shifts in tissue metabolism. In this paper, we examined global metabolic consequences of mucosal inflammation using both in vitro and in vivo models of disease. Initial analysis of the metabolic signature elicited by inflammation in epithelial models and in colonic tissue isolated from murine colitis demonstrated that levels of specific metabolites associated with cellular methylation reactions are significantly altered by model inflammatory systems. Furthermore, expression of enzymes central to all cellular methylation, S-adenosylmethionine synthetase and S-adenosylhomocysteine hydrolase, are increased in response to inflammation. Subsequent studies showed that DNA methylation is substantially increased during inflammation and that epithelial NF-κB activity is significantly inhibited following treatment with a reversible S-adenosylhomocysteine hydrolase inhibitor, DZ2002. Finally, these studies demonstrated that inhibition of cellular methylation in a murine model of colitis results in disease exacerbation while folate supplementation to promote methylation partially ameliorates the severity of murine colitis. Taken together, these results identify a global change in methylation, which during inflammation, translates to an overall protective role in mucosal epithelia.
Collapse
Affiliation(s)
- Douglas J Kominsky
- Department of Anesthesiology and Perioperative Medicine, University of Colorado Health Science Center, Aurora, CO 80045, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
203
|
De Vos M, Hindryckx P, Laukens D. Novel development in extraintestinal manifestations and spondylarthropathy. Best Pract Res Clin Gastroenterol 2011; 25 Suppl 1:S19-26. [PMID: 21640926 DOI: 10.1016/s1521-6918(11)70006-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The important co-existence of spondylarthritis (SpA) and inflammatory bowel disease (IBD) within the same individual suggests common etiopathogenic mechanisms. This is supported by intriguing similarities between both diseases at the subclinical and molecular level. The recent advances in IBD genetics have led to the identification of common pathways involved in both IBD and SpA, including bacterial recognition and ER stress. This offers the opportunity to develop potential new therapeutic strategies for both diseases. Transgenic animals which develop both joint and gut inflammation (like the TNF(ΔARE) mice and the HLA-B27 transgenic rats) are a very useful tool to test such novel therapeutics and to get further mechanistic insight into the pathogenetic link between SpA and IBD. This review will focus on the recent scientific progress in our understanding of the link between SpA and IBD. Based on this, potential novel therapeutic strategies are discussed.
Collapse
Affiliation(s)
- M De Vos
- Ghent University Hospital, Department of Gastroenterology, Ghent, Belgium.
| | | | | |
Collapse
|
204
|
Weiss GJ, Infante JR, Chiorean EG, Borad MJ, Bendell JC, Molina JR, Tibes R, Ramanathan RK, Lewandowski K, Jones SF, Lacouture ME, Langmuir VK, Lee H, Kroll S, Burris HA. Phase 1 study of the safety, tolerability, and pharmacokinetics of TH-302, a hypoxia-activated prodrug, in patients with advanced solid malignancies. Clin Cancer Res 2011; 17:2997-3004. [PMID: 21415214 DOI: 10.1158/1078-0432.ccr-10-3425] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The objectives of this phase 1, first-in-human study were to determine the dose-limiting toxicities (DLT), maximum tolerated dose (MTD), safety, pharmacokinetics, and preliminary activity of the hypoxia-activated prodrug TH-302 in patients with advanced solid tumors. EXPERIMENTAL DESIGN TH-302 was administered intravenously over 30 to 60 minutes in two regimens: three times weekly dosing followed by 1 week off (arm A) and every 3-week dosing (arm B). RESULTS Fifty-seven patients enrolled (arm A: N = 37 and arm B: N = 20). The TH-302 dose was escalated from 7.5 to 670 mg/m(2) in arm A and from 670 to 940 mg/m(2) in arm B. The most common adverse events were nausea, skin rash, fatigue, and vomiting. Hematologic toxicity was mild and limited. Grade 3 skin and mucosal toxicities were dose limiting at 670 mg/m(2) in arm A; the MTD was 575 mg/m(2). In arm B, grade 3 fatigue and grade 3 vaginitis/proctitis were dose limiting at 940 mg/m(2); the MTD was 670 mg/m(2). Plasma concentrations of TH-302 and the active metabolite Br-IPM (brominated version of isophosphoramide mustard) increased proportionally with dose. Two partial responses were noted in patients with metastatic small cell lung cancer (SCLC) and melanoma in arm A at 480 and 670 mg/m(2). Stable disease was observed in arms A and B in 18 and 9 patients, respectively. CONCLUSIONS The MTD of TH-302 was 575 mg/m(2) weekly and 670 mg/m(2) every 3 weeks. Skin and mucosal toxicities were DLTs. On the basis of responses in metastatic melanoma and SCLC, further investigations in these indications were initiated.
Collapse
Affiliation(s)
- Glen J Weiss
- Virginia G Piper Cancer Center at Scottsdale Healthcare/TGen, Scottsdale, Arizona 85238, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
205
|
New insights into the pathogenesis of inflammatory bowel disease: transcription factors analysis in bioptic tissues from pediatric patients. J Pediatr Gastroenterol Nutr 2011; 52:271-9. [PMID: 21336161 DOI: 10.1097/mpg.0b013e3182034d08] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVES Our work is aimed at identifying ex vivo new transcription factors, potentially involved in the pathogenesis of pediatric inflammatory bowel disease (IBD), by using a microarray approach. PATIENTS AND METHODS Microarray, including 84 transcription factors, was performed in inflamed and uninflamed mucosal tissues of pediatric patients with Crohn disease (CD) and in healthy controls. Real-time polymerase chain reaction was used to confirm microarray results on a larger size of CD and patients with ulcerative colitis (UC). Protein expression was evaluated by Western blot assay. RESULTS Microarray assay showed 40 genes differentially regulated in the inflamed mucosa and 17 in the uninflamed mucosa of patients with CD as compared with controls. Real-time polymerase chain reaction analysis revealed 10 transcripts in CD and 4 in UC, selected among those with higher differences as compared with healthy controls, significantly overexpressed in the inflamed tissues of patients. Moreover, 4 transcripts in CD and 2 in UC were found significantly upregulated in the uninvolved tissue. A further investigation evidenced an increased protein expression of activating transcription factor 3 and hypoxia-inducible transcription factor-1α in patients with CD as well as in Caco2 cell line stimulated by cytokines and hypoxia. CONCLUSIONS The present study shows an evident upregulation of several transcription factors in the inflamed and uninflamed mucosa of children with IBD, suggesting that the inflammatory process is somehow activated at molecular levels even in the macroscopically normal mucosa of patients. A differential pattern of gene expression between CD and UC indicates distinct molecular mechanisms underlying the pathogenesis of 2 diseases. Finally, activating transcription factor 3 and hypoxia-inducible transcription factor-1α are proposed as new transcription factors potentially involved in the onset and maintenance of IBD.
Collapse
|
206
|
Hart ML, Grenz A, Gorzolla IC, Schittenhelm J, Dalton JH, Eltzschig HK. Hypoxia-inducible factor-1α-dependent protection from intestinal ischemia/reperfusion injury involves ecto-5'-nucleotidase (CD73) and the A2B adenosine receptor. THE JOURNAL OF IMMUNOLOGY 2011; 186:4367-74. [PMID: 21357264 DOI: 10.4049/jimmunol.0903617] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Intestinal ischemia/reperfusion injury (IR) is characterized by intermittent loss of perfusion to the gut, resulting in dramatic increases in morbidity and mortality. Based on previous studies indicating an anti-inflammatory role for hypoxia-inducible factor (HIF)-1-elicited enhancement of extracellular adenosine production via ecto-5'-nucleotidase (CD73) and signaling through the A2B adenosine receptor (A2BAR), we targeted HIF-1 during IR using pharmacological or genetic approaches. Initial studies with pharmacological HIF activation indicated attenuation of intestinal injury with dimethyloxallyl glycine (DMOG) treatment during murine IR. Although DMOG treatment was associated with induction of CD73 transcript and protein, DMOG protection was abolished in cd73(-/-) mice. Similarly, DMOG treatment enhanced A2BAR transcript and protein levels, whereas DMOG protection was abolished in A2BAR(-/-) mice. Finally, studies of mice with conditional HIF-1α deletion in intestinal epithelia or pharmacological inhibition of HIF-1 with 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin revealed enhanced tissue injury during IR. These studies indicated a tissue-protective role of HIF-dependent enhancement of intestinal adenosine generation and signaling during intestinal IR.
Collapse
Affiliation(s)
- Melanie L Hart
- Department of Anesthesiology and Critical Care Medicine, Tübingen University Hospital, D-72074 Tübingen, Germany.
| | | | | | | | | | | |
Collapse
|
207
|
Affiliation(s)
- Holger K Eltzschig
- Department of Anesthesiology, University of Colorado Denver, Aurora, CO 80045, USA.
| | | |
Collapse
|
208
|
Vermeulen N, Vermeire S, Arijs I, Michiels G, Ballet V, Derua R, Waelkens E, Van Lommel L, Schuit F, Rutgeerts P, Bossuyt X. Seroreactivity against glycolytic enzymes in inflammatory bowel disease. Inflamm Bowel Dis 2011; 17:557-64. [PMID: 20629101 DOI: 10.1002/ibd.21388] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Patients with inflammatory bowel disease (IBD) carry autoantibodies such as perinuclear antineutrophil cytoplasmic antibodies. The aim of the current study was to further characterize the immune reactivity in IBD. METHODS We used an immunoproteomic approach with extracts from granulocytes and serum from ulcerative colitis (UC) patients and controls to identify target antigens. By means of Western blot analysis, we screened 60 UC and 60 Crohn's disease (CD) patients, 60 diseased, and 60 healthy controls for the antibodies. We performed gene array experiments on RNA extracted from colonic mucosal biopsies from 42 IBD patients and six controls. RESULTS We identified aldolase A, phosphoglycerate mutase, alpha-enolase, triose-phosphate isomerase, and malate dehydrogenase as target antigens in IBD. Seroreactivity to at least one of these five antigens was detected in 53.3% of UC patients, 38.3% of CD patients, and 8.3% of controls. Seroreactivity to at least two antigens was detected in 16.7% of UC patients, 11.7% of CD patients, and none of the controls. Gene array experiments showed a significant upregulation of aldolase A, phosphoglycerate mutase, alpha-enolase, and pyruvate kinase mRNA in biopsies from IBD patients, but not controls. UC and CD patients also showed enhanced expression of hypoxia-inducible factor-1, a transcription factor that induces expression of glycolytic enzymes. CONCLUSIONS IBD patients show strong seroreactivity toward enzymes involved in the glycolysis. IBD patients also have increased colonic mRNA expression of glycolytic enzymes, which is triggered by hypoxia through the transcription factor HIF-1.
Collapse
Affiliation(s)
- Nathalie Vermeulen
- Department of Internal Medicine, University Hospitals Leuven, Leuven, Belgium
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
209
|
Rolfe MD, Ter Beek A, Graham AI, Trotter EW, Asif HMS, Sanguinetti G, de Mattos JT, Poole RK, Green J. Transcript profiling and inference of Escherichia coli K-12 ArcA activity across the range of physiologically relevant oxygen concentrations. J Biol Chem 2011; 286:10147-54. [PMID: 21252224 DOI: 10.1074/jbc.m110.211144] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Oxygen availability is the major determinant of the metabolic modes adopted by Escherichia coli. Although much is known about E. coli gene expression and metabolism under fully aerobic and anaerobic conditions, the intermediate oxygen tensions that are encountered in natural niches are understudied. Here, for the first time, the transcript profiles of E. coli K-12 across the physiologically significant range of oxygen availabilities are described. These suggested a progressive switch to aerobic respiratory metabolism and a remodeling of the cell envelope as oxygen availability increased. The transcriptional responses were consistent with changes in the abundance of cytochrome bd and bo' and the outer membrane protein OmpW. The observed transcript and protein profiles result from changes in the activities of regulators that respond to oxygen itself or to metabolic and environmental signals that are sensitive to oxygen availability (aerobiosis). A probabilistic model (TFInfer) was used to predict the activity of the indirect oxygen-sensing two-component system ArcBA across the aerobiosis range. The model implied that the activity of the regulator ArcA correlated with aerobiosis but not with the redox state of the ubiquinone pool, challenging the idea that ArcA activity is inhibited by oxidized ubiquinone. The amount of phosphorylated ArcA correlated with the predicted ArcA activities and with aerobiosis, suggesting that fermentation product-mediated inhibition of ArcB phosphatase activity is the dominant mechanism for regulating ArcA activity under the conditions used here.
Collapse
Affiliation(s)
- Matthew D Rolfe
- The Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
210
|
Glover LE, Irizarry K, Scully M, Campbell EL, Bowers BE, Aherne CM, Kominsky DJ, MacManus CF, Colgan SP. IFN-γ attenuates hypoxia-inducible factor (HIF) activity in intestinal epithelial cells through transcriptional repression of HIF-1β. THE JOURNAL OF IMMUNOLOGY 2011; 186:1790-8. [PMID: 21199896 DOI: 10.4049/jimmunol.1001442] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Numerous studies have revealed that hypoxia and inflammation occur coincidentally in mucosal disorders, such as inflammatory bowel disease. During inflammation, epithelial-expressed hypoxia-inducible factor (HIF) serves an endogenously protective function. In this study, we sought to explore how mucosal immune responses influence HIF-dependent end points. Guided by a screen of relevant inflammatory mediators, we identified IFN-γ as a potent repressor of HIF-dependent transcription in human intestinal epithelial cells. Analysis of HIF levels revealed that HIF-1β, but not HIF-1α, is selectively repressed by IFN-γ in a JAK-dependent manner. Cloning and functional analysis of the HIF-1β promoter identified a prominent region for IFN-γ-dependent repression. Further studies revealed that colonic IFN-γ and HIF-1β levels were inversely correlated in a murine colitis model. Taken together, these studies demonstrated that intestinal epithelial HIF is attenuated by IFN-γ through transcriptional repression of HIF-1β. These observations are relevant to the pathophysiology of colitis (i.e., that loss of HIF signaling during active inflammation may exacerbate disease pathogenesis).
Collapse
Affiliation(s)
- Louise E Glover
- Mucosal Inflammation Program, Department of Medicine, University of Colorado Denver, Aurora, CO 80045, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
211
|
Hosoda A, Maruyama A, Oikawa D, Oshima Y, Komachi Y, Kanai G, Sato H, Iwawaki T. Detection of ER stress in vivo by Raman spectroscopy. Biochem Biophys Res Commun 2010; 405:37-41. [PMID: 21195060 DOI: 10.1016/j.bbrc.2010.12.112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 12/22/2010] [Indexed: 11/19/2022]
Abstract
The endoplasmic reticulum (ER) is an organelle in which most membrane and secretory proteins are synthesized. If these proteins are not folded correctly, unfolded proteins accumulate in the ER lumen, causing a cellular situation known as ER stress. Recently, many studies on the relationship between ER stress and diseases have been reported. Thus, studies of ER stress in vivo should yield information that is useful in pathology. Model mice have been developed as a powerful tool to visualize ER stress in vivo, but this approach depends on transgenic technology. Here, we report on a method of detecting ER stress in vivo by Raman spectroscopy. Our experiments revealed that two specific Raman bands were reduced in both cultured cells and animal tissues in an ER stress dependent manner. This suggests that Raman spectroscopy could be a useful tool to detect ER stress in vivo without transgenic technology.
Collapse
Affiliation(s)
- Akira Hosoda
- Iwawaki Initiative Research Unit, Advanced Science Institute, RIKEN, Wako, Saitama, Japan
| | | | | | | | | | | | | | | |
Collapse
|
212
|
Fitzpatrick SF, Tambuwala MM, Bruning U, Schaible B, Scholz CC, Byrne A, O'Connor A, Gallagher WM, Lenihan CR, Garvey JF, Howell K, Fallon PG, Cummins EP, Taylor CT. An intact canonical NF-κB pathway is required for inflammatory gene expression in response to hypoxia. THE JOURNAL OF IMMUNOLOGY 2010; 186:1091-6. [PMID: 21149600 DOI: 10.4049/jimmunol.1002256] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hypoxia is a feature of the microenvironment in a number of chronic inflammatory conditions due to increased metabolic activity and disrupted perfusion at the inflamed site. Hypoxia contributes to inflammation through the regulation of gene expression via key oxygen-sensitive transcriptional regulators including the hypoxia-inducible factor (HIF) and NF-κB. Recent studies have revealed a high degree of interdependence between HIF and NF-κB signaling; however, the relative contribution of each to hypoxia-induced inflammatory gene expression remains unclear. In this study, we use transgenic mice expressing luciferase under the control of NF-κB to demonstrate that hypoxia activates NF-κB in the heart and lungs of mice in vivo. Using small interfering RNA targeted to the p65 subunit of NF-κB, we confirm a unidirectional dependence of hypoxic HIF-1α accumulation upon an intact canonical NF-κB pathway in cultured cells. Cyclooxygenase-2 and other key proinflammatory genes are transcriptionally induced by hypoxia in a manner that is both HIF-1 and NF-κB dependent, and in mouse embryonic fibroblasts lacking an intact canonical NF-κB pathway, there is a loss of hypoxia-induced inflammatory gene expression. Finally, under conditions of hypoxia, HIF-1α and the p65 subunit of NF-κB directly bind to the cyclooxygenase-2 promoter. These results implicate an essential role for NF-κB signaling in inflammatory gene expression in response to hypoxia both through the regulation of HIF-1 and through direct effects upon target gene expression.
Collapse
Affiliation(s)
- Susan F Fitzpatrick
- UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
213
|
Tambuwala MM, Cummins EP, Lenihan CR, Kiss J, Stauch M, Scholz CC, Fraisl P, Lasitschka F, Mollenhauer M, Saunders SP, Maxwell PH, Carmeliet P, Fallon PG, Schneider M, Taylor CT. Loss of prolyl hydroxylase-1 protects against colitis through reduced epithelial cell apoptosis and increased barrier function. Gastroenterology 2010; 139:2093-101. [PMID: 20600011 DOI: 10.1053/j.gastro.2010.06.068] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 05/27/2010] [Accepted: 06/21/2010] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Hypoxia inducible factor (HIF) prolyl hydroxylase inhibitors are protective in mouse models of inflammatory bowel disease (IBD). Here, we investigated the therapeutic target(s) and mechanism(s) involved. METHODS The effect of genetic deletion of individual HIF-prolyl hydroxylase (PHD) enzymes on the development of dextran sulphate sodium (DSS)-induced colitis was examined in mice. RESULTS PHD1(-/-), but not PHD2(+/-) or PHD3(-/-), mice were less susceptible to the development of colitis than wild-type controls as determined by weight loss, disease activity, colon histology, neutrophil infiltration, and cytokine expression. Reduced susceptibility of PHD1(-/-) mice to colitis was associated with increased density of colonic epithelial cells relative to wild-type controls, which was because of decreased levels of apoptosis that resulted in enhanced epithelial barrier function. Furthermore, with the use of cultured epithelial cells it was confirmed that hydroxylase inhibition reversed DSS-induced apoptosis and barrier dysfunction. Finally, PHD1 levels were increased with disease severity in intestinal tissue from patients with IBD and in colonic tissues from DSS-treated mice. CONCLUSIONS These results imply a role for PHD1 as a positive regulator of intestinal epithelial cell apoptosis in the inflamed colon. Genetic loss of PHD1 is protective against colitis through decreased epithelial cell apoptosis and consequent enhancement of intestinal epithelial barrier function. Thus, targeted PHD1 inhibition may represent a new therapeutic approach in IBD.
Collapse
|
214
|
Lin S, Lee SJ, Shim H, Chun J, Yun CC. The absence of LPA receptor 2 reduces the tumorigenesis by ApcMin mutation in the intestine. Am J Physiol Gastrointest Liver Physiol 2010; 299:G1128-38. [PMID: 20724530 PMCID: PMC2993170 DOI: 10.1152/ajpgi.00321.2010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Lysophosphatidic acid (LPA) is a lipid mediator that mediates several effects that promote cancer progress. The LPA receptor type 2 (LPA(2)) expression is often elevated in several types of cancers, including colorectal cancer (CRC). In this study, we investigated the role of LPA(2) in the development of intestinal adenomas by comparing Apc(Min/+) mice with Apc(Min/+)/Lpar2(-/-) mice. There were 50% fewer intestinal adenomas in Apc(Min/+)/Lpar2(-/-) mice than Apc(Min/+) mice. Smaller-size adenomas (<1 mm) were found at higher frequencies in Apc(Min/+)/Lpar2(-/-) mice compared with Apc(Min/+) mice at the two age groups examined. The expression level of LPA(2) correlated with increased size of intestinal adenomas. Reduced tumor multiplicity and size in Apc(Min/+)/Lpar2(-/-) mice correlated with decreased proliferation of intestinal epithelial cells. Apc(Min/+)/Lpar2(-/-) mice showed an increased level of apoptosis, suggesting that LPA(2)-mediated signaling stimulates intestinal tumor development and progress by regulating both cell proliferation and survival. In addition, the expression levels of Krüpple-like factor 5 (KLF5), β-catenin, cyclin D1, c-Myc, and hypoxia-inducible factor-1α (HIF-1α) were significantly altered in Apc(Min/+)/Lpar2(-/-) mice compared with Apc(Min/+) mice. In vitro studies using HCT116 cells showed that LPA induced cyclin D1, c-Myc, and HIF-1α expression, which was attenuated by knockdown of LPA(2). In summary, intestinal tumor initiated by Apc mutations is altered by LPA(2)-mediated signaling, which regulates tumor growth and survival by altering multiple targets.
Collapse
Affiliation(s)
- Songbai Lin
- 1Division of Digestive Diseases, Departments of Medicine and
| | - Sei-Jung Lee
- 1Division of Digestive Diseases, Departments of Medicine and
| | | | - Jerold Chun
- 5Department of Molecular Biology, Scripps Research Institute, La Jolla, California
| | - C. Chris Yun
- 1Division of Digestive Diseases, Departments of Medicine and ,3Winship Cancer Institute and ,4Department of Physiology, Emory University School of Medicine, Atlanta, Georgia; and
| |
Collapse
|
215
|
Hindryckx P, De Vos M, Jacques P, Ferdinande L, Peeters H, Olievier K, Bogaert S, Brinkman B, Vandenabeele P, Elewaut D, Laukens D. Hydroxylase inhibition abrogates TNF-alpha-induced intestinal epithelial damage by hypoxia-inducible factor-1-dependent repression of FADD. THE JOURNAL OF IMMUNOLOGY 2010; 185:6306-16. [PMID: 20943999 DOI: 10.4049/jimmunol.1002541] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Hydroxylase inhibitors stabilize hypoxia-inducible factor-1 (HIF-1), which has barrier-protective activity in the gut. Because the inflammatory cytokine TNF-α contributes to inflammatory bowel disease in part by compromising intestinal epithelial barrier integrity, hydroxylase inhibition may have beneficial effects in TNF-α-induced intestinal epithelial damage. The hydroxylase inhibitor dimethyloxalylglycin (DMOG) was tested in a murine model of TNF-α-driven chronic terminal ileitis. DMOG-treated mice experienced clinical benefit and showed clear attenuation of chronic intestinal inflammation compared with that of vehicle-treated littermates. Additional in vivo and in vitro experiments revealed that DMOG rapidly restored terminal ileal barrier function, at least in part through prevention of TNF-α-induced intestinal epithelial cell apoptosis. Subsequent transcriptional studies indicated that DMOG repressed Fas-associated death domain protein (FADD), a critical adaptor molecule in TNFR-1-mediated apoptosis, in an HIF-1α-dependent manner. Loss of this FADD repression by HIF-1α-targeting small interfering RNA significantly diminished the antiapoptotic action of DMOG. Additional molecular studies led to the discovery of a previously unappreciated HIF-1 binding site in the FADD promoter, which controls repression of FADD during hypoxia. As such, the results reported in this study allowed the identification of an innate mechanism that protects intestinal epithelial cells during (inflammatory) hypoxia, by direct modulation of death receptor signaling. Hydroxylase inhibition could represent a promising alternative treatment strategy for hypoxic inflammatory diseases, including inflammatory bowel disease.
Collapse
Affiliation(s)
- Pieter Hindryckx
- Department of Gastroenterology, Ghent University, Ghent, Belgium
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
216
|
Newton IP, Kenneth NS, Appleton PL, Näthke I, Rocha S. Adenomatous polyposis coli and hypoxia-inducible factor-1{alpha} have an antagonistic connection. Mol Biol Cell 2010; 21:3630-8. [PMID: 20844082 PMCID: PMC2965681 DOI: 10.1091/mbc.e10-04-0312] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We demonstrate a novel link between APC and hypoxia and show that APC and HIF-1α; antagonize each other. Hypoxia represses APC mRNA via HIF-1α. On the other hand, APC-mediated repression of HIF-1α requires wild-type APC, low levels of β-catenin, and NF-κB activity. The tumor suppressor adenomatous polyposis coli (APC) is mutated in the majority of colorectal cancers and is best known for its role as a scaffold in a Wnt-regulated protein complex that determines the availability of β-catenin. Another common feature of solid tumors is the presence of hypoxia as indicated by the up-regulation of hypoxia-inducible factors (HIFs) such as HIF-1α. Here, we demonstrate a novel link between APC and hypoxia and show that APC and HIF-1α antagonize each other. Hypoxia results in reduced levels of APC mRNA and protein via a HIF-1α–dependent mechanism. HIF-1α represses the APC gene via a functional hypoxia-responsive element on the APC promoter. In contrast, APC-mediated repression of HIF-1α requires wild-type APC, low levels of β-catenin, and nuclear factor-κB activity. These results reveal down-regulation of APC as a new mechanism that contributes to the survival advantage induced by hypoxia and also show that loss of APC mutations produces a survival advantage by mimicking hypoxic conditions.
Collapse
Affiliation(s)
- Ian P Newton
- Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
| | | | | | | | | |
Collapse
|
217
|
Vannay A, Sziksz E, Prókai A, Veres G, Molnár K, Szakál DN, Onódy A, Korponay-Szabó IR, Szabó A, Tulassay T, Arató A, Szebeni B. Increased expression of hypoxia-inducible factor 1alpha in coeliac disease. Pediatr Res 2010; 68:118-22. [PMID: 20453713 DOI: 10.1203/pdr.0b013e3181e5bc96] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Previously, it has been suggested that hypoxia-inducible factor (HIF) 1 signaling may play determinative role in the maintenance of the barrier function of the intestinal epithelium in inflammatory bowel disease. Our aim was to depict the alteration of HIF-1alpha and related genes in celiac disease (CD) where the importance of the barrier function is well known. Duodenal biopsy specimens were collected from 16 children with untreated CD, 9 children with treated CD and 10 controls. HIF-1alpha, trefoil factor 1 (TFF1), ecto-5-prime nucleotidase (CD73), and multi drug resistance gene 1 (MDR1) mRNA and HIF-1alpha protein expression were determined by real-time PCR and Western blot, respectively. Localization of HIF-1alpha was determined by immunofluorescent staining. We found increased HIF-1alpha and TFF1 mRNA and HIF-1alpha protein expression in the duodenal mucosa of children with untreated CD compared with controls or children with treated CD (p < 0.05). In untreated CD children, HIF-1alpha staining was present in cytoplasmic and nuclear region of the villous enterocytes. In treated CD mRNA expression of CD73 and MDR1 were increased compared with controls (p < 0.01 and 0.05, respectively). Our results of increased mucosal HIF-1alpha expression in CD children suggest the contribution of this signaling pathway in the pathomechanism of CD.
Collapse
Affiliation(s)
- Adám Vannay
- First Department of Pediatrics, Semmelweis University, H-1083 Budapest, Hungary
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
218
|
Kominsky DJ, Campbell EL, Colgan SP. Metabolic shifts in immunity and inflammation. THE JOURNAL OF IMMUNOLOGY 2010; 184:4062-8. [PMID: 20368286 DOI: 10.4049/jimmunol.0903002] [Citation(s) in RCA: 306] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Sites of ongoing inflammation and triggered immune responses are characterized by significant changes in metabolic activity. Recent studies have indicated that such shifts in tissue metabolism result from a combination of profound recruitment of inflammatory cells (neutrophils and monocytes) and high proliferation rates among lymphocyte populations. The resultant shifts in energy supply and demand can result in metabolic acidosis and diminished delivery and/or availability of oxygen, leading to hypoxia extensive enough to trigger transcriptional and translation changes in tissue phenotype. Such phenotypic shifts can imprint fundamental changes to tissue metabolism. In this study, we review recent work addressing metabolic changes and metabolic control of inflammation and immunity.
Collapse
Affiliation(s)
- Douglas J Kominsky
- Department of Anesthesiology, University of Colorado Denver Health Sciences Center, Aurora, CO 80045, USA
| | | | | |
Collapse
|
219
|
Harris NR, Carter PR, Lee S, Watts MN, Zhang S, Grisham MB. Association between blood flow and inflammatory state in a T-cell transfer model of inflammatory bowel disease in mice. Inflamm Bowel Dis 2010; 16:776-82. [PMID: 19821506 PMCID: PMC2856723 DOI: 10.1002/ibd.21126] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Adoptive transfer of naive T-lymphocyte subsets into lymphopenic mice initiates chronic gut inflammation that mimics several aspects of inflammatory bowel disease (IBD). Patients with IBD can have profound alterations in intestinal blood flow, but whether the same is true in the T-cell transfer model has yet to be determined. METHODS In the current study, chronic intestinal inflammation was induced in recombinase-activating gene-1-deficient (RAG(-/-)) mice by adoptive transfer of CD4(+) T-lymphocytes obtained from interleukin-10 deficient (IL-10(-/-)) mice. RESULTS Four weeks later, widespread colonic inflammation was observed in the reconstituted recipients, in contrast to 2 control sets of mice injected with a different subset of lymphocytes or with vehicle alone. We observed that the resulting pathology induced in the reconstituted RAG(-/-) mice was divided distinctly into 2 subsets: 1 with blood flow near normal with very high inflammation scores, and the other with severely attenuated blood flow but with much lower signs of inflammation. Colonic and ileal blood flow rates in the latter subset of CD4(+) mice averaged only approximately 30% compared to the mice with higher inflammation scores. The lower blood flow rates were associated with greatly reduced red blood cell concentrations in the tissue, suggesting a possible loss of vascular density. CONCLUSIONS In this model of chronic intestinal inflammation, mild inflammation was associated with significant decreases in blood flow.
Collapse
Affiliation(s)
- Norman R. Harris
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA USA
| | - Patsy R. Carter
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA USA
| | - Seungjun Lee
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA USA
| | - Megan N. Watts
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA USA
| | - Songlin Zhang
- Department of Pathology, Louisiana State University Health Sciences Center, Shreveport, LA USA
| | - Matthew B. Grisham
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA USA
| |
Collapse
|
220
|
Abstract
Intestinal epithelial cells that line the mucosal surface of the gastrointestinal tract are positioned between an anaerobic lumen and a highly metabolic lamina propria. As a result of this unique anatomy, intestinal epithelial cells function within a steep physiologic oxygen gradient relative to other cell types. Furthermore, during active inflammatory disease such as IBD, metabolic shifts towards hypoxia are severe. Studies in vitro and in vivo have shown that the activation of hypoxia-inducible factor (HIF) serves as an alarm signal to promote the resolution of inflammation in various mouse models of disease. Amelioration of disease occurs, at least in part, through transcriptional upregulation of nonclassic epithelial barrier genes. There is much interest in harnessing hypoxia-inducible pathways, including stabilizing HIF directly or via inhibition of prolyl hydroxylase enzymes, for therapy of IBD. In this Review, we discuss the signaling pathways involved in the regulation of hypoxia and discuss how hypoxia may serve as an endogenous alarm signal for the presence of mucosal inflammatory disease. We also discuss the pros and cons of targeting these pathways to treat patients with IBD.
Collapse
Affiliation(s)
- Sean P. Colgan
- Mucosal Inflammation Program, Division of Gastroenterology, Mucosal Inflammation Program, University of Colorado Denver, 12700 E. 19th Ave MS B146, Aurora, CO 80045, USA
| | - Cormac T. Taylor
- UCD Conway Institute, School of Medicine and Medical Science, College of Life Sciences, University College Dublin, Belfield, Dublin 4, Ireland
| |
Collapse
|
221
|
Nagel S, Talbot NP, Mecinović J, Smith TG, Buchan AM, Schofield CJ. Therapeutic manipulation of the HIF hydroxylases. Antioxid Redox Signal 2010; 12:481-501. [PMID: 19754349 DOI: 10.1089/ars.2009.2711] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The hypoxia-inducible factor (HIF) family of transcription factors is responsible for coordinating the cellular response to low oxygen levels in animals. By regulating the expression of a large array of target genes during hypoxia, these proteins also direct adaptive changes in the hematopoietic, cardiovascular, and respiratory systems. They also play roles in pathological processes, including tumorogenesis. In recent years, several oxygenases have been identified as key molecular oxygen sensors within the HIF system. The HIF hydroxylases regulate the stability and transcriptional activity of the HIF-alpha subunit by catalyzing hydroxylation of specific proline and asparaginyl residues, respectively. They require oxygen and 2-oxoglutarate (2OG) as co-substrates, and depend upon non-heme ferrous iron (Fe(II)) as a cofactor. This article summarizes current understanding of the biochemistry of the HIF hydroxylases, identifies targets for their pharmacological manipulation, and discusses their potential in the therapeutic manipulation of the HIF system.
Collapse
Affiliation(s)
- Simon Nagel
- Acute Stroke Programme, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Headington, Oxford, United Kingdom
| | | | | | | | | | | |
Collapse
|
222
|
Hindryckx P, Waeytens A, Laukens D, Peeters H, Van Huysse J, Ferdinande L, Carmeliet P, De Vos M. Absence of placental growth factor blocks dextran sodium sulfate-induced colonic mucosal angiogenesis, increases mucosal hypoxia and aggravates acute colonic injury. J Transl Med 2010; 90:566-76. [PMID: 20142801 DOI: 10.1038/labinvest.2010.37] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Angiogenesis has recently been described as a component of inflammatory bowel disease. Placental growth factor (PlGF), a vascular endothelial growth factor (VEGF) homologue, establishes its angiogenic capacity under pathophysiological conditions. We investigated the function of PlGF in experimental models of acute colitis. Acute colonic damage was induced in PlGF knock-out ((-/-)) mice and PlGF wild-type ((+/+)) mice by dextran sodium sulfate (DSS) and trinitrobenzenesulfonic acid (TNBS). The concentrations of PlGF and VEGF were measured in distal colonic lysates using an enzyme-linked immunosorbent assay. Colonic injury was evaluated by assessing colon length, colonocyte apoptosis (by terminal dUTP nick-end labeling), colonic cytokine production and histological score. Infiltration of polymorphonuclear cells was determined by assaying myeloperoxidase (MPO) activity. In a separate experiment, recombinant PlGF was administered to PlGF(-/-) mice by adenoviral transfer before DSS administration. Mucosal vascularization was quantified by computerized morphometric analysis of CD31-stained distal colonic sections. Colonic mucosal hypoxia was visualized by pimonidazole staining. Both VEGF and PlGF were upregulated during acute colitis. In addition, compared with PlGF(+/+) controls, PlGF(-/-) mice showed a significant increase in weight loss and colonic shortening during both DSS and TNBS colitis. This correlated with enhanced colonocyte apoptosis, elevated colonic cytokine levels and increased histological damage score, but not with enhanced inflammatory cell infiltration (MPO activity). The increased morbidity of PlGF(-/-) mice during DSS colitis was preventable by adenovirus (Ad)-mediated overexpression of PlGF. After the administration of DSS, strongly reduced mucosal angiogenesis was observed in PlGF(-/-) mice compared with PlGF(+/+) mice. This was associated with an early increase in intestinal epithelial pimonidazole accumulation in PlGF(-/-) mice, suggesting a function of enhanced epithelial hypoxia in the observed differences between the two groups. In summary, our data show that the absence of PlGF strongly inhibits mucosal intestinal angiogenesis in acute colitis, which is associated with an early increase in intestinal epithelial hypoxia and aggravation of the course of the disease.
Collapse
Affiliation(s)
- Pieter Hindryckx
- Department of Gastroenterology, Ghent University, De Pintelaan 185, Gent, Belgium.
| | | | | | | | | | | | | | | |
Collapse
|
223
|
|
224
|
Eltzschig HK, Rivera-Nieves J, Colgan SP. Targeting the A2B adenosine receptor during gastrointestinal ischemia and inflammation. Expert Opin Ther Targets 2009; 13:1267-77. [PMID: 19769545 DOI: 10.1517/14728220903241666] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Extracellular adenosine functions as an endogenous distress signal via activation of four distinct adenosine receptors (A1, A2A, A2B and A3). Conditions of limited oxygen availability or acute inflammation lead to elevated levels of extracellular adenosine and enhanced signaling events. This relates to a combination of four mechanisms: i) increased production of adenosine via extracellular phosphohydrolysis of precursor molecules (particularly ATP and ADP); ii) increased expression and signaling via hypoxia-induced adenosine receptors, particularly the A2B adenosine receptor; iii) attenuated uptake from the extracellular towards the intracellular compartment; and iv) attenuated intracellular metabolism. Due to their large surface area, mucosal organs are particularly prone to hypoxia and ischemia associated inflammation. Therefore, it is not surprising that adenosine production and signaling plays a central role in attenuating tissue inflammation and injury during intestinal ischemia or inflammation. In fact, recent studies combining pharmacological and genetic approaches demonstrated that adenosine signaling via the A2B adenosine receptor dampens mucosal inflammation and tissue injury during intestinal ischemia or experimental colitis. This review outlines basic principles of extracellular adenosine production, signaling, uptake and metabolism. In addition, we discuss the role of this pathway in dampening hypoxia-elicited inflammation, specifically in the setting of intestinal ischemia and inflammation.
Collapse
Affiliation(s)
- Holger K Eltzschig
- University of Colorado, Mucosal Inflammation Program, Department of Medicine, Denver, 12700 E 19th Avenue, Mailstop B112, Research Complex 2, Room 7124, Aurora, CO 80045, USA.
| | | | | |
Collapse
|
225
|
Keely S, Glover LE, Weissmueller T, MacManus CF, Fillon S, Fennimore B, Colgan SP. Hypoxia-inducible factor-dependent regulation of platelet-activating factor receptor as a route for gram-positive bacterial translocation across epithelia. Mol Biol Cell 2009; 21:538-46. [PMID: 20032301 PMCID: PMC2820419 DOI: 10.1091/mbc.e09-07-0573] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Results from these studies reveal that some strains of Gram-positive bacteria exploit hypoxia-inducible factor-regulated platelet-activating factor receptor as a means for translocation through intestinal epithelial cells. Mucosal surfaces, such as the lung and intestine, are lined by a monolayer of epithelia that provides tissue barrier and transport function. It is recently appreciated that a common feature of inflammatory processes within the mucosa is hypoxia (so-called inflammatory hypoxia). Given the strong association between bacterial translocation and mucosal inflammatory disease, we hypothesized that intestinal epithelial hypoxia influences bacterial translocation. Initial studies revealed that exposure of cultured intestinal epithelia to hypoxia (pO2, 20 torr; 24–48 h) resulted in a increase of up to 40-fold in the translocation of some strains of Gram-positive bacteria, independently of epithelial barrier function. A screen of relevant pathway inhibitors identified a prominent role for the platelet-activating factor receptor (PAFr) in hypoxia-associated bacterial translocation, wherein pharmacologic antagonists of PAFr blocked bacterial translocation by as much as 80 ± 6%. Extensions of these studies revealed that hypoxia prominently induces PAFr through a hypoxia-inducible factor (HIF)-dependent mechanism. Indeed, HIF and PAFr loss of function studies (short hairpin RNA) revealed that apically expressed PAFr is central to the induction of translocation for the Gram-positive bacteria Enterococcus faecalis. Together, these findings reveal that some strains of Gram-positive bacteria exploit HIF-regulated PAFr as a means for translocation through intestinal epithelial cells.
Collapse
Affiliation(s)
- Simon Keely
- Mucosal Inflammation Program, Department of Medicine, University of Colorado Denver, Aurora, CO 80045, USA.
| | | | | | | | | | | | | |
Collapse
|
226
|
Saijo F, Milsom AB, Bryan NS, Bauer SM, Vowinkel T, Ivanovic M, Andry C, Granger DN, Rodriguez J, Feelisch M. On the dynamics of nitrite, nitrate and other biomarkers of nitric oxide production in inflammatory bowel disease. Nitric Oxide 2009; 22:155-67. [PMID: 20005300 DOI: 10.1016/j.niox.2009.11.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 11/20/2009] [Accepted: 11/30/2009] [Indexed: 12/18/2022]
Abstract
Nitrite and nitrate are frequently used surrogate markers of nitric oxide (NO) production. Using rat models of acute and chronic DSS-induced colitis we examined the applicability of these and other NO-related metabolites, in tissues and blood, for the characterization of inflammatory bowel disease. Global NO dynamics were assessed by simultaneous quantification of nitrite, nitrate, nitroso and nitrosyl species over time in multiple compartments. NO metabolite levels were compared to a composite disease activity index (DAI) and contrasted with measurements of platelet aggregability, ascorbate redox status and the effects of 5-aminosalicylic acid (5-ASA). Nitroso products in the colon and in other organs responded in a manner consistent with the DAI. In contrast, nitrite and nitrate, in both intra- and extravascular compartments, exhibited variations that were not always in step with the DAI. Extravascular nitrite, in particular, demonstrated significant temporal instabilities, ranging from systemic drops to marked increases. The latter was particularly evident after cessation of the inflammatory stimulus and accompanied by profound ascorbate oxidation. Treatment with 5-ASA effectively reversed these fluctuations and the associated oxidative and nitrosative stress. Platelet activation was enhanced in both the acute and chronic model. Our results offer a first glimpse into the systemic nature of DSS-induced inflammation and reveal a greater complexity of NO metabolism than previously envisioned, with a clear dissociation of nitrite from other markers of NO production. The remarkable effectiveness of 5-ASA to abrogate the observed pattern of nitrite instability suggests a hitherto unrecognized role of this molecule in either development or resolution of inflammation. Its possible link to tissue oxygen consumption and the hypoxia that tends to accompany the inflammatory process warrants further investigation.
Collapse
Affiliation(s)
- Fumito Saijo
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
227
|
Taylor CT, Cummins EP. The role of NF-kappaB in hypoxia-induced gene expression. Ann N Y Acad Sci 2009; 1177:178-84. [PMID: 19845620 DOI: 10.1111/j.1749-6632.2009.05024.x] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Hypoxia is a common physiologic and pathophysiologic stimulus that activates the expression of genes through oxygen-sensitive transcription factors including the hypoxia-inducible factor (HIF) and nuclear factor-kappaB (NF-kappaB). Hypoxia-dependent gene expression can have important physiologic or pathophysiologic consequences for an organism, depending upon the cause of the hypoxic insult. Consequently, this pathway represents an attractive therapeutic target in a number of disease states. While the mechanism linking hypoxia to the activation of HIF has been extensively studied, our understanding of how hypoxia activates NF-kappaB is limited. Recent studies have demonstrated that similar oxygen-sensing mechanisms are employed in conferring oxygen sensitivity to both HIF and NF-kappaB-dependent gene expression. Furthermore, there is an extensive degree of cross-talk occurring between NF-kappaB and HIF. Investigations into mechanisms of hypoxic activation of HIF and NF-kappaB and how these signaling pathways interact will uncover new therapeutic modalities in a diverse range of disease states where hypoxia is a feature of the microenvironment including cancer, vascular disease, and chronic inflammation.
Collapse
Affiliation(s)
- Cormac T Taylor
- UCD Conway Institute, School of Medicine and Medical Science, College of Life Science, University College Dublin, Belfield, Dublin, Ireland.
| | | |
Collapse
|
228
|
Matthijsen RA, Derikx JPM, Kuipers D, van Dam RM, Dejong CHC, Buurman WA. Enterocyte shedding and epithelial lining repair following ischemia of the human small intestine attenuate inflammation. PLoS One 2009; 4:e7045. [PMID: 19753114 PMCID: PMC2737143 DOI: 10.1371/journal.pone.0007045] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Accepted: 07/28/2009] [Indexed: 12/13/2022] Open
Abstract
Background Recently, we observed that small-intestinal ischemia and reperfusion was found to entail a rapid loss of apoptotic and necrotic cells. This study was conducted to investigate whether the observed shedding of ischemically damaged epithelial cells affects IR induced inflammation in the human small gut. Methods and Findings Using a newly developed IR model of the human small intestine, the inflammatory response was studied on cellular, protein and mRNA level. Thirty patients were consecutively included. Part of the jejunum was subjected to 30 minutes of ischemia and variable reperfusion periods (mean reperfusion time 120 (±11) minutes). Ethical approval and informed consent were obtained. Increased plasma intestinal fatty acid binding protein (I-FABP) levels indicated loss in epithelial cell integrity in response to ischemia and reperfusion (p<0.001 vs healthy). HIF-1α gene expression doubled (p = 0.02) and C3 gene expression increased 4-fold (p = 0.01) over the course of IR. Gut barrier failure, assessed as LPS concentration in small bowel venous effluent blood, was not observed (p = 0.18). Additionally, mRNA expression of HO-1, IL-6, IL-8 did not alter. No increased expression of endothelial adhesion molecules, TNFα release, increased numbers of inflammatory cells (p = 0.71) or complement activation, assessed as activated C3 (p = 0.14), were detected in the reperfused tissue. Conclusions In the human small intestine, thirty minutes of ischemia followed by up to 4 hours of reperfusion, does not seem to lead to an explicit inflammatory response. This may be explained by a unique mechanism of shedding of damaged enterocytes, reported for the first time by our group.
Collapse
Affiliation(s)
- Robert A. Matthijsen
- Department of Surgery, School for Nutrition & Metabolism (NUTRIM), Maastricht University Medical Center, Maastricht, the Netherlands
| | - Joep P. M. Derikx
- Department of Surgery, School for Nutrition & Metabolism (NUTRIM), Maastricht University Medical Center, Maastricht, the Netherlands
| | - Dian Kuipers
- Department of Surgery, School for Nutrition & Metabolism (NUTRIM), Maastricht University Medical Center, Maastricht, the Netherlands
| | - Ronald M. van Dam
- Department of Surgery, School for Nutrition & Metabolism (NUTRIM), Maastricht University Medical Center, Maastricht, the Netherlands
| | - Cornelis H. C. Dejong
- Department of Surgery, School for Nutrition & Metabolism (NUTRIM), Maastricht University Medical Center, Maastricht, the Netherlands
| | - Wim A. Buurman
- Department of Surgery, School for Nutrition & Metabolism (NUTRIM), Maastricht University Medical Center, Maastricht, the Netherlands
- * E-mail:
| |
Collapse
|
229
|
Edwards RA, Witherspoon M, Wang K, Afrasiabi K, Pham T, Birnbaumer L, Lipkin SM. Epigenetic repression of DNA mismatch repair by inflammation and hypoxia in inflammatory bowel disease-associated colorectal cancer. Cancer Res 2009; 69:6423-9. [PMID: 19638594 DOI: 10.1158/0008-5472.can-09-1285] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Sporadic human mismatch repair (MMR)-deficient colorectal cancers account for approximately 12.5% of all cases of colorectal cancer. MMR-deficient colorectal cancers are classically characterized by right-sided location, multifocality, mucinous histology, and lymphocytic infiltration. However, tumors in germ-line MMR-deficient mouse models lack these histopathologic features. Mice lacking the heterotrimeric G protein alpha subunit Gialpha2 develop chronic colitis and multifocal, right-sided cancers with mucinous histopathology, similar to human MMR-deficient colorectal cancer. Young Gialpha2-/- colonic epithelium has normal MMR expression but selectively loses MLH1 and consequently PMS2 expression following inflammation. Gialpha2-/- cancers have microsatellite instability. Mlh1 is epigenetically silenced not by promoter hypermethylation but by decreased histone acetylation. Chronically inflamed Gialpha2-/- colonic mucosa contains patchy hypoxia, with increased crypt expression of the hypoxia markers DEC-1 and BNIP3. Chromatin immunoprecipitation identified increased binding of the transcriptional repressor DEC-1 to the proximal Mlh1 promoter in hypoxic YAMC cells and colitic Gialpha2-/- crypts. Treating Gialpha2-/- mice with the histone deacetylase inhibitor suberoylanilide hydroxamic acid significantly decreased colitis activity and rescued MLH1 expression in crypt epithelial cells, which was associated with increased acetyl histone H3 levels and decreased DEC-1 binding at the proximal Mlh1 promoter, consistent with a histone deacetylase-dependent mechanism. These data link chronic hypoxic inflammation, epigenetic MMR protein down-regulation, development of MMR-deficient colorectal cancer, and the firstmouse model of somatically acquired MMR-deficient colorectal cancer.
Collapse
Affiliation(s)
- Robert A Edwards
- Department of Pathology, University of California-Irvine, Irvine, California 92697-4800, USA.
| | | | | | | | | | | | | |
Collapse
|
230
|
Abstract
Metazoan organisms are dependent on a continuous supply of O(2) for survival. Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that regulates oxygen homeostasis and plays key roles in development, physiology, and disease. HIF-1 activity is induced in response to continuous hypoxia, intermittent hypoxia, growth factor stimulation, and Ca(2+) signaling. HIF-1 mediates adaptive responses to hypoxia, including erythropoiesis, angiogenesis, and metabolic reprogramming. In each case, HIF-1 regulates the expression of multiple genes encoding key components of the response pathway. HIF-1 also mediates maladaptive responses to chronic continuous and intermittent hypoxia, which underlie the development of pulmonary and systemic hypertension, respectively.
Collapse
Affiliation(s)
- Gregg L Semenza
- Vascular Program, Institute for Cell Engineering, McKusick-Nathans Institute of Genetic Medicine, Baltimore, Maryland, USA.
| |
Collapse
|
231
|
Mastrogiannaki M, Matak P, Keith B, Simon MC, Vaulont S, Peyssonnaux C. HIF-2alpha, but not HIF-1alpha, promotes iron absorption in mice. J Clin Invest 2009; 119:1159-66. [PMID: 19352007 DOI: 10.1172/jci38499] [Citation(s) in RCA: 373] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 02/23/2009] [Indexed: 12/16/2022] Open
Abstract
HIF transcription factors (HIF-1 and HIF-2) are central mediators of cellular adaptation to hypoxia. Because the resting partial pressure of oxygen is low in the intestinal lumen, epithelial cells are believed to be mildly hypoxic. Having recently established a link between HIF and the iron-regulatory hormone hepcidin, we hypothesized that HIFs, stabilized in the hypoxic intestinal epithelium, may also play critical roles in regulating intestinal iron absorption. To explore this idea, we first established that the mouse duodenum, the site of iron absorption in the intestine, is hypoxic and generated conditional knockout mice that lacked either Hif1a or Hif2a specifically in the intestinal epithelium. Using these mice, we found that HIF-1alpha was not necessary for iron absorption, whereas HIF-2alpha played a crucial role in maintaining iron balance in the organism by directly regulating the transcription of the gene encoding divalent metal transporter 1 (DMT1), the principal intestinal iron transporter. Specific deletion of Hif2a led to a decrease in serum and liver iron levels and a marked decrease in liver hepcidin expression, indicating the involvement of an induced systemic response to counteract the iron deficiency. This finding may provide a basis for the development of new strategies, specifically in targeting HIF-2alpha, to improve iron homeostasis in patients with iron disorders.
Collapse
|
232
|
Oliver KM, Taylor CT, Cummins EP. Hypoxia. Regulation of NFkappaB signalling during inflammation: the role of hydroxylases. Arthritis Res Ther 2009; 11:215. [PMID: 19291263 PMCID: PMC2688226 DOI: 10.1186/ar2575] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
NFκB is a master regulator of innate immunity and inflammatory signalling. Microenvironmental hypoxia has long been identified as being coincident with chronic inflammation. The contribution of microenvironmental hypoxia to NFκB-induced inflammation has more recently been appreciated. Identification of the co-regulation of NFκB and hypoxia inducible factor (HIF) pathways by 2-oxo-glutarate-dependent hydroxylase family members has highlighted an intimate relationship between NFκB inflammatory signalling and HIF-mediated hypoxic signalling pathways. Adding another layer of complexity to our understanding of the role of NFκB inflammatory signalling by hypoxia is the recent recognition of the contribution of basal NFκB activity to HIF-1α transcription. This observation implicates an important and previously unappreciated role for NFκB in inflammatory disease where HIF-1α is activated. The present review will discuss recent literature pertaining to the regulation of NFκB inflammatory signalling by hypoxia and some of the inflammatory diseases where this may play an important role. Furthermore, we will discuss the potential for prolylhydroxylase inhibitors in inflammatory disease.
Collapse
Affiliation(s)
- Kathryn M Oliver
- School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
| | | | | |
Collapse
|
233
|
Kaser A, Blumberg RS. Endoplasmic reticulum stress in the intestinal epithelium and inflammatory bowel disease. Semin Immunol 2009; 21:156-63. [PMID: 19237300 DOI: 10.1016/j.smim.2009.01.001] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 01/20/2009] [Indexed: 02/06/2023]
Abstract
The unfolded protein response as a consequence of endoplasmic reticulum (ER) stress has recently been implicated as a novel mechanism that may lead to inflammatory bowel disease (IBD). Impairment of proper ER stress resolution in highly secretory Paneth and, to a lesser extent, goblet cells within the epithelium can primarily lead to intestinal inflammation. An inability to manage ER stress may not only be a primary originator of intestinal inflammation as exemplified by genetic polymorphisms in XBP1 that are associated with IBD but also a perpetuator of inflammation when ER stress is induced secondarily to inflammatory mediators or microbial factors. Furthermore, ER stress pathways may interact with other processes that lead to IBD, notably autophagy.
Collapse
Affiliation(s)
- Arthur Kaser
- Department of Medicine II (Gastroenterology and Hepatology), Innsbruck Medical University, Innsbruck, Austria
| | | |
Collapse
|
234
|
Binion DG, Rafiee P. Is inflammatory bowel disease a vascular disease? Targeting angiogenesis improves chronic inflammation in inflammatory bowel disease. Gastroenterology 2009; 136:400-3. [PMID: 19111728 DOI: 10.1053/j.gastro.2008.12.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
|
235
|
Roifman I, Sun YC, Fedwick JP, Panaccione R, Buret AG, Liu H, Rostom A, Anderson TJ, Beck PL. Evidence of endothelial dysfunction in patients with inflammatory bowel disease. Clin Gastroenterol Hepatol 2009; 7:175-82. [PMID: 19121648 DOI: 10.1016/j.cgh.2008.10.021] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 10/20/2008] [Accepted: 10/21/2008] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Chronic inflammation has a major role in the development and propagation of endothelial dysfunction, which can lead to coronary artery disease. Endothelial dysfunction has been described in patients with various and diverse chronic inflammatory conditions. Altered vascular flow has been proposed to mediate inflammation in inflammatory bowel disease (IBD), although the role of endothelial dysfunction remains obscure. The purpose of our study was to assess endothelial function in patients with IBD. METHODS Ninety-eight subjects were included in this study; 48 with IBD (17 with ulcerative colitis and 31 with Crohn's disease) and 50 healthy controls. Endothelial function was assessed by pulse arterial tonometry (PAT) and brachial ultrasound to determine flow-mediated dilation and shear stress reactive hyperemia. The impact of disease activity, disease duration, and IBD therapy also was assessed. RESULTS Baseline demographic characteristics, including cardiovascular risk factors, were similar in all groups. IBD patients showed microvascular endothelial dysfunction, with lower PAT indices (P < .01) and shear stress reactive hyperemia (P < .05) compared with controls. There was no relationship between microvascular endothelial dysfunction, disease duration, underlying therapy, or clinical disease activity. There was a positive association between lower PAT scores and recent abdominal pain (P < .05). CONCLUSIONS This was a large study assessing endothelial dysfunction in IBD. Both ulcerative colitis and Crohn's disease patients showed evidence of microvascular endothelial dysfunction. Future research could determine whether endothelial dysfunction is involved in the pathogenesis of IBD or increases the risk of cardiovascular events in this patient population.
Collapse
Affiliation(s)
- Idan Roifman
- Division of Gastroenterology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
236
|
Inhibition of oxygen sensors as a therapeutic strategy for ischaemic and inflammatory disease. Nat Rev Drug Discov 2009; 8:139-52. [PMID: 19165233 DOI: 10.1038/nrd2761] [Citation(s) in RCA: 275] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cells in the human body need oxygen to function and survive, and severe deprivation of oxygen, as occurs in ischaemic heart disease and stroke, is a major cause of mortality. Nevertheless, other organisms, such as the fossorial mole rat or diving seals, have acquired the ability to survive in conditions of limited oxygen supply. Hypoxia tolerance also allows the heart to survive chronic oxygen shortage, and ischaemic preconditioning protects tissues against lethal hypoxia. The recent discovery of a new family of oxygen sensors--including prolyl hydroxylase domain-containing proteins 1-3 (PHD1-3)--has yielded exciting novel insights into how cells sense oxygen and keep oxygen supply and consumption in balance. Advances in understanding of the role of these oxygen sensors in hypoxia tolerance, ischaemic preconditioning and inflammation are creating new opportunities for pharmacological interventions for ischaemic and inflammatory diseases.
Collapse
|
237
|
Cui PL, Lv D, Zhang J, Yao SW, Wang YB, Yang ZX. Oxidative stress damage and HIF-1α expression in rat intestinal mucosa during acute necrotic pancreatitis. Shijie Huaren Xiaohua Zazhi 2009; 17:24-30. [DOI: 10.11569/wcjd.v17.i1.24] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To examine the role of oxidative stress in intestinal mucosal barrier damage during ANP, and to explore the putative mechanism of HIF-1α during this process.
METHODS: Male Wistar rats were divided randomly into three groups: group A (n = 18) and B (n = 18) served as ANP models, group C (n = 10) was designated as a normal control (sham operation). In group A and C, rats were treated with normal saline therapy, while in group B, rats were treated with DMSO therapy. During the observation period, the morphological changes of intestinal mucosa and pancreatic tissue were observed, and the intestinal permeability was evaluated by FITC-labeled Dextran method and DAO activity detection. The activities of SOD, MPO and the level of MDA and GSH were measured and also the expression of HIF-1α protein was assayed.
RESULTS: During the observation period of ANP, the intestinal mucosal barrier function was damaged seriously and the intestinal permeability was increased. As early as 6h, the DAO activity in the mucosa was decreased obviously (0.43 ± 0.07 U/L vs 0.91 ± 0.11 U/L, P < 0.05) while was attenuated by administration of DMSO. In the serum, the detection of DAO activity showed an opposite results. Also in ANP group, the activity of SOD and the level of GSH were highly decreased (SOD: 12.12 ± 2.24 U/mg vs 25.12 ± 3.86 U/mg; GSH: 160.75 ± 24.25 mg/g vs 412.45 ± 45.60 mg/g, both P < 0.01), while the activity of MPO and the level of MDA were markedly increased (MPO: 1.32 ± 0.18 U/mg vs 0.63 ± 0.11 U/mg; MDA: 2.85 ± 0.21 nmol/mg vs 1.34 ± 0.12 nmol/mg, both P < 0.01). However, administration of DMSO attenuated the damage to some extent, and mucosal barrier function was improved (P < 0.05). And the injury induced by oxidative stress was limited to some extent (P < 0.05). Western blot showed the expression of HIF-1α protein was up-regulated with ANP while down-regulated with DMSO.
CONCLUSION: The intestinal mucosal barrier is damaged during the process of ANP; oxidative stress plays an important role in the damage to mucosal barrier and OFR scavenger could maintain the integrity of mucosal barrier structure and function; HIF-1α is involved in the protection effect on intestinal mucosal barrier under hypoxia induced by ANP, which could be regulated through attenuating the mucosal barrier damage when OFR scavenger is used.
Collapse
|
238
|
Abstract
Extracellular adenosine is produced in a coordinated manner from cells following cellular challenge or tissue injury. Once produced, it serves as an autocrine- and paracrine-signaling molecule through its interactions with seven-membrane-spanning G-protein-coupled adenosine receptors. These signaling pathways have widespread physiological and pathophysiological functions. Immune cells express adenosine receptors and respond to adenosine or adenosine agonists in diverse manners. Extensive in vitro and in vivo studies have identified potent anti-inflammatory functions for all of the adenosine receptors on many different inflammatory cells and in various inflammatory disease processes. In addition, specific proinflammatory functions have also been ascribed to adenosine receptor activation. The potent effects of adenosine signaling on the regulation of inflammation suggest that targeting specific adenosine receptor activation or inactivation using selective agonists and antagonists could have important therapeutic implications in numerous diseases. This review is designed to summarize the current status of adenosine receptor signaling in various inflammatory cells and in models of inflammation, with an emphasis on the advancement of adenosine-based therapeutics to treat inflammatory disorders.
Collapse
Affiliation(s)
- Michael R Blackburn
- Department of Biochemistry and Molecular Biology, The University of Texas-Houston Medical School, Houston, TX 77030, USA.
| | | | | | | |
Collapse
|
239
|
Keely S, Glover LE, MacManus CF, Campbell EL, Scully MM, Furuta GT, Colgan SP. Selective induction of integrin beta1 by hypoxia-inducible factor: implications for wound healing. FASEB J 2008; 23:1338-46. [PMID: 19103643 DOI: 10.1096/fj.08-125344] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Because of localized vascular damage and increased tissue oxygen demand, wound healing occurs in a relatively hypoxic microenvironment. These features are particularly relevant to wound healing and fibrosis in chronic inflammatory conditions, such as Crohn's disease and ulcerative colitis. In these studies, we sought to identify the contribution of hypoxia to mechanisms of wound repair in a model of the intestinal submucosa. Initial studies revealed that hypoxia promotes wound healing, as modeled by an increase in intestinal fibroblast-mediated collagen gel contraction. Guided by results from transcriptional profiling, we identified the selective induction of fibroblast integrin beta1 (ITGB1) by hypoxia. Further analysis revealed that hypoxia, as well as pharmacological activators of hypoxia-inducible factor (HIF), induce fibroblast beta1 integrin mRNA, protein, and function by as much as 4-fold. Cloning and analysis of the beta1 integrin gene promoter revealed a 10 +/- 0.8-fold increase in promoter activity in response to hypoxia, and subsequent studies identified a functional DNA binding region for HIF in the ITGB1 gene promoter. Mutational analysis of the HIF binding site within the ITGB1 promoter resulted in a significant loss of ITGB1 hypoxia-inducibility. As proof of principle, studies in a murine model of colitis revealed a correlation between colitic disease severity and tissue ITGB1 expression (R(2)=0.80). Taken together, these results demonstrate that hypoxia induces fibroblast ITGB1 expression and function by transcriptional mechanisms dependent on HIF.
Collapse
Affiliation(s)
- Simon Keely
- Mucosal Inflammation Program, Department of Medicine, University of Colorado Denver, Aurora, CO 80045, USA
| | | | | | | | | | | | | |
Collapse
|
240
|
Neutrophils as sources of extracellular nucleotides: functional consequences at the vascular interface. Trends Cardiovasc Med 2008; 18:103-7. [PMID: 18436149 DOI: 10.1016/j.tcm.2008.01.006] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2007] [Revised: 01/29/2008] [Accepted: 01/31/2008] [Indexed: 11/23/2022]
Abstract
Nucleotide signaling is currently an area of intense investigation. Extracellular adenosine triphosphate (ATP) liberated during hypoxia or inflammation can either signal directly to purinergic receptors or, after phosphohydrolytic metabolism, can activate surface adenosine receptors. Given the association of polymorphonuclear leukocytes (PMNs) with adenine nucleotide/nucleoside signaling in the inflammatory milieu, it was recently demonstrated that PMNs actively release ATP via a connexin 43 hemichannel-dependent mechanism. Here, we review the mechanisms of ATP release and subsequent functional implications of ATP metabolism at the interface between PMN and vascular endothelial cells during inflammation and in hypoxia.
Collapse
|
241
|
Taylor CT. Interdependent roles for hypoxia inducible factor and nuclear factor-kappaB in hypoxic inflammation. J Physiol 2008; 586:4055-9. [PMID: 18599532 DOI: 10.1113/jphysiol.2008.157669] [Citation(s) in RCA: 259] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Decreased oxygen availability (hypoxia) is a hallmark feature of the microenvironment in a number of chronic inflammatory conditions including arthritis and inflammatory bowel disease (IBD). Recent advances in our understanding of oxygen-dependent cell signalling have uncovered several mechanisms by which hypoxia impacts upon the development of inflammation through the coordinated expression of adaptive, inflammatory and apoptotic genes. Two central transcription factors involved in the regulation of this response are hypoxia inducible factor (HIF) and nuclear factor-kappaB (NF-kappaB) which display different degrees of sensitivity to activation during hypoxia. Furthermore, HIF and NF-kappaB demonstrate an intimate interdependence at several mechanistic levels. Recent studies indicate that these pathways may represent important new therapeutic targets in diseases characterized by hypoxic inflammation.
Collapse
Affiliation(s)
- Cormac T Taylor
- UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
| |
Collapse
|
242
|
The expanding universe of hypoxia. J Mol Med (Berl) 2008; 86:739-46. [PMID: 18551266 DOI: 10.1007/s00109-008-0364-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Revised: 04/23/2008] [Accepted: 04/24/2008] [Indexed: 10/22/2022]
Abstract
Reduced oxygen availability (hypoxia) is sensed and transduced into changes in the activity or expression of cellular macromolecules. These responses impact on virtually all areas of biology and medicine. In this meeting report, we summarize major developments in the field that were presented at the 2008 Keystone Symposium on Cellular, Physiological, and Pathogenic Responses to Hypoxia.
Collapse
|
243
|
Chin MP, Schauer DB, Deen WM. Prediction of nitric oxide concentrations in colonic crypts during inflammation. Nitric Oxide 2008; 19:266-75. [PMID: 18501201 DOI: 10.1016/j.niox.2008.04.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 04/14/2008] [Accepted: 04/29/2008] [Indexed: 02/07/2023]
Abstract
Nitric oxide production in the colon has been linked to inflammatory bowel disease (IBD) and increased risk for colon cancer. However, measurements of NO concentration in the inflamed colon have not been available and it is not known what NO levels are pathophysiological. A computational model, based on anatomical length scales and rates of NO production measured in cell cultures, was used to predict spatially varying NO concentrations within a colonic crypt under inflammatory conditions. A variety of scenarios were considered, including different spatial distributions of macrophages and a range of possible macrophage and epithelial synthesis rates for NO. Activated macrophages arranged as a monolayer at the base of the crypt elicited maximum NO concentrations of approximately 0.3 microM. The epithelial contribution to NO synthesis was calculated to be negligible. Assuming a uniform macrophage layer, NO synthesis rates greater than 20 microM/s, or more than three times that measured in vitro, would be necessary to achieve maximum NO concentrations of 1 microM in the crypt. Thus, unless NO synthesis rates in macrophages and/or epithelial cells greatly exceed those measured in cell cultures, NO concentrations will remain submicromolar in the crypt during inflammation. Additionally, the results were used to predict the range of NO concentrations (<0.3 microM) and cumulative NO dose (560 microM min) experienced by a given epithelial cell migrating from the base to the top of the crypt. These estimates of NO concentrations in inflamed crypts should facilitate efforts to elucidate the molecular biological linkage between NO exposure and carcinogenesis in IBD.
Collapse
Affiliation(s)
- Melanie P Chin
- Department of Chemical Engineering, Massachusetts Institute of Technology, Room 66-572, Cambridge, MA 02139, USA
| | | | | |
Collapse
|