Ecto-5′-nucleotidase (CD73) regulation by hypoxia-inducible factor-1 mediates permeability changes in intestinal epithelia

Synnestvedt, Kristin; Furuta, Glenn T.; Comerford, Katrina M.; Louis, Nancy A.; Karhausen, Jörn; Eltzschig, Holger K.; Hansen, Karl R.; Thompson, Linda F.; Colgan, Sean P.

doi:10.1172/jci15337

Cited by 334 publications

(201 citation statements)

References 57 publications

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“…We therefore hypothesized that Col1 production is more sensitive to A 2A R activation than Col3 so that increasing concentrations of CGS21680 would decrease the Col1:Col3 ratio. Interestingly, hypoxia increases adenosine extracellular levels by suppressing both adenosine uptake and metabolism [30][31][32][33] and, at the same time, conditions of hypoxia promote fibrogenesis [34]. Moreover, HIF-1α induces A 2B R expression [35] indicating that the A 2B R exerts a tissue protective function [36,37], but the A 2A R may also contribute to the functions of adenosine in ischemic settings [35,36].…”

Section: Discussionmentioning

confidence: 99%

Adenosine A2A receptor (A2AR) is a fine-tune regulator of the collagen1:collagen3 balance

Pérez-Aso

Mediero

Cronstein

2013

Purinergic Signalling

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Adenosine is a potent endogenous anti-inflammatory and immunosuppressive metabolite that is a potent modulator of tissue repair. However, the adenosine A 2A receptor (A 2A R)-mediated promotion of collagen synthesis is detrimental in settings such as scarring and scleroderma. The signaling cascade from A 2A R stimulation to increased collagen production is complex and obscure, not least because cAMP and its downstream molecules PKA and Epac1 have been reported to inhibit collagen production. We therefore examined A 2A R-stimulated signaling for collagen production by normal human dermal fibroblasts (NHDF). Collagen1 (Col1) and collagen3 (Col3) content after A 2A R activation by CGS21680 was studied by western blotting. Contribution of PKA and Epac was analyzed by the PKA inhibitor PKI and by knockdowns of the PKA-Cα, -Cβ, -Cγ, Epac1, and Epac2. CGS21680 stimulates Col1 expression at significantly lower concentrations than those required to stimulate Col3 expression. A 2A R stimulates Col1 expression by a PKA-dependent mechanism since PKA inhibition or PKA-Cα and -Cβ knockdown prevents A 2A R-mediated Col1 increase. In contrast, A 2A R represses Col3 via PKA but stimulates both Col1 and Col3 via an Epac2-dependent mechanism. A 2A R stimulation with CGS21680 at 0.1 μM increased Col3 expression only upon PKA blockade. A 2A R activation downstream signaling for Col1 and Col3 expression proceeds via two distinct pathways with varying sensitivity to cAMP activation; more highly cAMPsensitive PKA activation stimulates Col1 expression, and less cAMP-sensitive Epac activation promotes both Col1 and Col3 expression. These observations may explain the dramatic change in Col1:Col3 ratio in hypertrophic and immature scars, where adenosine is present in higher concentrations than in normal skin.

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Section: Discussionmentioning

confidence: 99%

Adenosine A2A receptor (A2AR) is a fine-tune regulator of the collagen1:collagen3 balance

Pérez-Aso

Mediero

Cronstein

2013

Purinergic Signalling

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“…A beneficial effect of an increased adenine nucleotide/adenosine ratio is compatible with an improved endothelial barrier function following block of CD73 [3]. However, it should also be pointed out that a blunted capability of adenosine production by CD73 may be detrimental under conditions of acute lung injury induced by mechanical ventilation [4] or under hypoxic stress in lung [5] or intestinal mucosa [6]. Thus, it is unlikely that the beneficial effects of DHA treatment are caused by adenosine, because its production is rather decreased after DHA (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Protective effects observed after blunting of CD73 activity include reduced airway responsiveness after allergen exposure [1], reduced hepatic fibrosis generation [2], and decreased endothelial layer permeability [3]. In contrast, augmented tissue injury after blunting of adenosine production by CD73 has been reported under conditions of acute lung injury induced by mechanical ventilation [4], hypoxic lung injury [5] and hypoxia induced hyperpermeability of intestinal mucosa [6]. …”

Section: Introductionmentioning

confidence: 99%

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Regulation of Ecto-5´-Nucleotidase by Docosahexaenoic Acid in Human Endothelial Cells

Thom¹,

Wendel²,

Deußen³

2013

Cell Physiol Biochem

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Background/Aims: Modulation of extracellular adenine nucleotide and adenosine concentrations is one potential mechanism by which docosahexaenoic acid (DHA) may exert beneficial effects in critically ill patients. This study assessed DHA effects on extracellular adenine purines. Methods: Experiments used human pulmonary endothelial cells (HPMEC) and umbilical vein endothelial cells (HUVEC) treated with DHA (48 h). mRNA level (real-time PCR), expression (western blot, flow cytometry) and activities (hydrolysis of etheno(ε)-purines and fluorescence HPLC) of CD73 (ecto-5´-nucleotidase) and CD39 (ecto-NTPDase-1) were quantified. Results: DHA elevated total CD73 membrane protein expression concentration-dependently but CD73 mRNA level did not change. Increased expression was paralleled by increased enzyme activity. Effects observed on membrane level were reversed in intact cells, in which ε-AMP hydrolysis decreased after DHA. In intact endothelial cells ATP release was enhanced and CD39 activity blunted following DHA treatment. Hence, extracellular ATP and ADP concentrations increased and this inhibited ε-AMP hydrolysis. Conclusion: In human endothelial cells DHA caused 1) up-regulation of CD73 protein content and increased AMP hydrolysis at the cell membrane level, 2) increased cellular ATP release, and 3) decreased extracellular ATP/ADP hydrolysis. Thus, reorganization of the extracellular adenine-nucleotide-adenosine axis in response to DHA resulted in an increased extracellular ATP/adenosine ratio.

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“…HIF-1 demonstrates protective functions within intestinal inflammatory pathologies such as colitis [9,10,11,12,13,14]. Its transcriptional activity influences key target genes which are involved in mucosal barrier maintenance and restitution, including vascular endothelial growth factor (VEGF) [15], inducible nitric oxide synthase (iNOS) [16], intestinal trefoil factor (ITF) [11], P-glycoprotein 1 or multidrug resistance protein 1 (MDR-1) [17], adenosine A 2A/2B receptors [15,18] and ecto-5'-nucleotidase (CD73) [19]. The transcriptional activity of HIF-1 is dictated by the bioavailability of the HIF-1α subunit [8,10].…”

Section: Introductionmentioning

confidence: 99%

Effects of Nitric Oxide and Reactive Oxygen Species on HIF-1a Stabilization FollowingClostridium DifficileToxin Exposure of the Caco-2 Epithelial Cell Line

Lee¹,

Hirota²,

Glover

et al. 2013

Cell Physiol Biochem

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Background/Aims: Stabilization of the hypoxia-inducible factor (HIF-1α) is proposed to provide a protective host-response to C. difficile intoxication. Here, we aimed to elucidate whether nitric oxide and/or reactive oxygen species produced during C. difficile toxin exposure could influence HIF-1α stability and initiate protection against epithelial cell damage. Methods/Results: HIF-1α and inducible nitric oxide synthase (iNOS) proteins were up-regulated whereas factor-inhibiting HIF-1 (FIH-1) protein was down-regulated in Caco-2 epithelial cell monolayers with in vitro toxin exposure. We demonstrate using the biotin-switch assay that the stabilization of HIF-1α protein occurred via iNOS-dependent nitrosylation. Inhibition of iNOS activity by selective inhibitor (1400W) attenuated HIF-1α stabilization and exacerbated toxin-dependent disruptions in Caco-2 monolayer morphology and tight junctional integrity in vitro. Treatment of Caco-2 cell monolayers with N-actylcysteine (NAC), a scavenger of reactive oxygen species (ROS), attenuated toxin-dependent increases in iNOS and HIF-1α protein levels but had no effect on FIH-1 responses. In addition, mice that were exposed to C. difficile toxin in vivo also demonstrated a significant increase in HIF-1α protein and nitrosylation levels. Conclusion: Taken together, these data suggest that important synergistic actions exist between nitric oxide and ROS to stabilize HIF-1α and its innate, protective actions in the context of C. difficile toxin-mediated epithelial injury.

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Ecto-5′-nucleotidase (CD73) regulation by hypoxia-inducible factor-1 mediates permeability changes in intestinal epithelia

Cited by 334 publications

References 57 publications

Adenosine A2A receptor (A2AR) is a fine-tune regulator of the collagen1:collagen3 balance

Adenosine A2A receptor (A2AR) is a fine-tune regulator of the collagen1:collagen3 balance

Regulation of Ecto-5´-Nucleotidase by Docosahexaenoic Acid in Human Endothelial Cells

Effects of Nitric Oxide and Reactive Oxygen Species on HIF-1a Stabilization FollowingClostridium DifficileToxin Exposure of the Caco-2 Epithelial Cell Line

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