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Vaughn B, Robson SC, Burnstock G. Pathological roles of purinergic signaling in the liver. J Hepatol 2012; 57:916-20. [PMID: 22709619 PMCID: PMC3732799 DOI: 10.1016/j.jhep.2012.06.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 05/31/2012] [Accepted: 06/06/2012] [Indexed: 12/04/2022]
Abstract
Purinergic signaling has been postulated as a mechanism of cellular signaling since the early 1970s. Cellular responses triggered by extracellular nucleotides and nucleosides occur by defined adenosine (P1) and ATP (P2) receptors, respectively, and play a prominent role in many aspects of health and disease, including those involving the liver. In normal physiology, extracellular nucleotides modulate many of the normal biologic and hepatic metabolic processes such as gluconeogenesis and insulin responsiveness. Further, in multiple disease states, ATP and certain nucleotides serve as danger signals and are involved in heightened purinergic receptor activation in a myriad of pathologic processes. Recently, others and we have shown the regulation of purinergic signaling by ectonucleotidases to play an important role in the acute vascular pathobiology of liver inflammation, regeneration, and immunity, as in ischemia reperfusion and transplantation. Increased understanding into mechanisms of extracellular ATP metabolism by such ecto enzymes has also led to novel insights into the exquisite balance of nucleotide P2-receptor and adenosinergic P1-receptor signaling in those chronic hepatic diseases characterized by steatosis, fibrosis, and malignancy. This review will explore the developing role of purinergic signaling in the pathophysiology of liver disease and comment on potential future clinical applications.
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Affiliation(s)
| | - Simon C. Robson
- Corresponding Author: Simon C Robson MD PhD, Division of Gastroenterology, CLS 612, Beth Israel Deaconess Medical Centre/Harvard Medical School, Boston MA 02215 USA. tel - 617 735 2921, fax - 617 735 2930,
| | - Geoffrey Burnstock
- Autonomic Neuroscience Centre University College Medical School, Royal Free Campus, London, UK
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Zimmerman M, Tak E, Kaplan M, Mandell MS, Eltzschig HK, Grenz A. Use of a hanging-weight system for liver ischemia in mice. J Vis Exp 2012:e2550. [PMID: 22895458 PMCID: PMC3486745 DOI: 10.3791/2550] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Acute liver injury due to ischemia can occur during several clinical procedures e.g. liver transplantation, hepatic tumor resection or trauma repair and can result in liver failure which has a high mortality rate1-2. Therefore murine studies of hepatic ischemia have become an important field of research by providing the opportunity to utilize pharmacological and genetic studies3-9. Specifically, conditional mice with tissue specific deletion of a gene (cre, flox system) provide insights into the role of proteins in particular tissues10-13 . Because of the technical difficulty associated with manually clamping the portal triad in mice, we performed a systematic evaluation using a hanging-weight system for portal triad occlusion which has been previously described3. By using a hanging-weight system we place a suture around the left branch of the portal triad without causing any damage to the hepatic lobes, since also the finest clamps available can cause hepatic tissue damage because of the close location of liver tissue to the vessels. Furthermore, the right branch of the hepatic triad is still perfused thus no intestinal congestion occurs with this technique as blood flow to the right hepatic lobes is preserved. Furthermore, the portal triad is only manipulated once throughout the entire surgical procedure. As a result, procedures like pre-conditioning, with short times of ischemia and reperfusion, can be easily performed. Systematic evaluation of this model by performing different ischemia and reperfusion times revealed a close correlation of hepatic ischemia time with liver damage as measured by alanine (ALT) and aspartate (AST) aminotransferase serum levels3,9. Taken together, these studies confirm highly reproducible liver injury when using the hanging-weight system for hepatic ischemia and intermittent reperfusion. Thus, this technique might be useful for other investigators interested in liver ischemia studies in mice. Therefore the video clip provides a detailed step-by-step description of this technique.
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van Golen RF, van Gulik TM, Heger M. The sterile immune response during hepatic ischemia/reperfusion. Cytokine Growth Factor Rev 2012; 23:69-84. [PMID: 22609105 DOI: 10.1016/j.cytogfr.2012.04.006] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 04/16/2012] [Indexed: 12/14/2022]
Abstract
Hepatic ischemia and reperfusion elicits an immune response that lacks a microbial constituent yet poses a potentially lethal threat to the host. In this sterile setting, the immune system is alarmed by endogenous danger signals that are release by stressed and dying liver cells. The detection of these immunogenic messengers by sentinel leukocyte populations constitutes the proximal trigger for a self-perpetuating cycle of inflammation, in which consecutive waves of cytokines and chemokines orchestrate the influx of various leukocyte subsets that ultimately confer tissue destruction. This review focuses on the temporal organization of sterile hepatic inflammation, using surgery-induced trauma as a template disease state.
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Affiliation(s)
- Rowan F van Golen
- Department of Experimental Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Fausther M, Lecka J, Soliman E, Kauffenstein G, Pelletier J, Sheung N, Dranoff JA, Sévigny J. Coexpression of ecto-5'-nucleotidase/CD73 with specific NTPDases differentially regulates adenosine formation in the rat liver. Am J Physiol Gastrointest Liver Physiol 2012; 302:G447-59. [PMID: 22135310 PMCID: PMC3287391 DOI: 10.1152/ajpgi.00165.2011] [Citation(s) in RCA: 48] [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
Ectonucleotidases modulate purinergic signaling by hydrolyzing ATP to adenosine. Here we characterized the impact of the cellular distribution of hepatic ectonucleotidases, namely nucleoside triphosphate diphosphohydrolase (NTPDase)1/CD39, NTPDase2/CD39L1, NTPDase8, and ecto-5'-nucleotidase/CD73, and of their specific biochemical properties, on the levels of P1 and P2 receptor agonists, with an emphasis on adenosine-producing CD73. Immunostaining and enzyme histochemistry showed that the distribution of CD73 (protein and AMPase activity) overlaps partially with those of NTPDase1, -2, and -8 (protein levels and ATPase and ADPase activities) in normal rat liver. CD73 is expressed in fibroblastic cells located underneath vascular endothelial cells and smooth muscle cells, which both express NTPDase1, in portal spaces in a distinct fibroblast population next to NTPDase2-positive portal fibroblasts, and in bile canaliculi, together with NTPDase8. In fibrotic rat livers, CD73 protein expression and activity are redistributed but still overlap with the NTPDases mentioned. The ability of the observed combinations of ectonucleotidases to generate adenosine over time was evaluated by reverse-phase HPLC with the recombinant rat enzymes at high "inflammatory" (500 μM) and low "physiological" (1 μM) ATP concentrations. Overall, ATP was rapidly converted to adenosine by the NTPDase1+CD73 combination, but not by the NTPDase2+CD73 combination. In the presence of NTPDase8 and CD73, ATP was sequentially dephosphorylated to the CD73 inhibitor ADP, and then to AMP, thus resulting in a delayed formation of adenosine. In conclusion, the specific cellular cocompartmentalization of CD73 with hepatic NTPDases is not redundant and may lead to the differential activation of P1 and P2 receptors, under normal and fibrotic conditions.
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Affiliation(s)
- Michel Fausther
- 1Centre de recherche en Rhumatologie et Immunologie, Centre Hospitalier Universitaire de Québec (pavillon CHUL), Québec and Département de microbiologie-infectiologie et d'immunologie, Faculté de médecine, Université Laval, Québec, QC, Canada; ,2Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut; and ,3Division of Gastroenterology and Hepatology, Department of Internal Medicine, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Joanna Lecka
- 1Centre de recherche en Rhumatologie et Immunologie, Centre Hospitalier Universitaire de Québec (pavillon CHUL), Québec and Département de microbiologie-infectiologie et d'immunologie, Faculté de médecine, Université Laval, Québec, QC, Canada;
| | - Elwy Soliman
- 2Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut; and
| | - Gilles Kauffenstein
- 1Centre de recherche en Rhumatologie et Immunologie, Centre Hospitalier Universitaire de Québec (pavillon CHUL), Québec and Département de microbiologie-infectiologie et d'immunologie, Faculté de médecine, Université Laval, Québec, QC, Canada;
| | - Julie Pelletier
- 1Centre de recherche en Rhumatologie et Immunologie, Centre Hospitalier Universitaire de Québec (pavillon CHUL), Québec and Département de microbiologie-infectiologie et d'immunologie, Faculté de médecine, Université Laval, Québec, QC, Canada;
| | - Nina Sheung
- 2Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut; and
| | - Jonathan A. Dranoff
- 2Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut; and ,3Division of Gastroenterology and Hepatology, Department of Internal Medicine, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Jean Sévigny
- 1Centre de recherche en Rhumatologie et Immunologie, Centre Hospitalier Universitaire de Québec (pavillon CHUL), Québec and Département de microbiologie-infectiologie et d'immunologie, Faculté de médecine, Université Laval, Québec, QC, Canada;
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Kalogeris T, Baines CP, Krenz M, Korthuis RJ. Cell biology of ischemia/reperfusion injury. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 298:229-317. [PMID: 22878108 PMCID: PMC3904795 DOI: 10.1016/b978-0-12-394309-5.00006-7] [Citation(s) in RCA: 1366] [Impact Index Per Article: 113.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Disorders characterized by ischemia/reperfusion (I/R), such as myocardial infarction, stroke, and peripheral vascular disease, continue to be among the most frequent causes of debilitating disease and death. Tissue injury and/or death occur as a result of the initial ischemic insult, which is determined primarily by the magnitude and duration of the interruption in the blood supply, and then subsequent damage induced by reperfusion. During prolonged ischemia, ATP levels and intracellular pH decrease as a result of anaerobic metabolism and lactate accumulation. As a consequence, ATPase-dependent ion transport mechanisms become dysfunctional, contributing to increased intracellular and mitochondrial calcium levels (calcium overload), cell swelling and rupture, and cell death by necrotic, necroptotic, apoptotic, and autophagic mechanisms. Although oxygen levels are restored upon reperfusion, a surge in the generation of reactive oxygen species occurs and proinflammatory neutrophils infiltrate ischemic tissues to exacerbate ischemic injury. The pathologic events induced by I/R orchestrate the opening of the mitochondrial permeability transition pore, which appears to represent a common end-effector of the pathologic events initiated by I/R. The aim of this treatise is to provide a comprehensive review of the mechanisms underlying the development of I/R injury, from which it should be apparent that a combination of molecular and cellular approaches targeting multiple pathologic processes to limit the extent of I/R injury must be adopted to enhance resistance to cell death and increase regenerative capacity in order to effect long-lasting repair of ischemic tissues.
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Affiliation(s)
- Theodore Kalogeris
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, USA
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56
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Kukulski F, Lévesque SA, Sévigny J. Impact of ectoenzymes on p2 and p1 receptor signaling. ADVANCES IN PHARMACOLOGY 2011; 61:263-99. [PMID: 21586362 DOI: 10.1016/b978-0-12-385526-8.00009-6] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
P2 receptors that are activated by extracellular nucleotides (e.g., ATP, ADP, UTP, UDP, Ap(n)A) and P1 receptors activated by adenosine control a diversity of biological processes. The activation of these receptors is tightly regulated by ectoenzymes that metabolize their ligands. This review presents these enzymes as well as their roles in the regulation of P2 and P1 receptor activation. We focus specifically on the role of ectoenzymes in processes of our interest, that is, inflammation, vascular tone, and neurotransmission. An update on the development of ectonucleotidase inhibitors is also presented.
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Affiliation(s)
- Filip Kukulski
- Centre de Recherche en Rhumatologie et Immunologie, Centre Hospitalier Universitaire de Québec, Québec, Canada
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57
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Zhai Y, Busuttil RW, Kupiec-Weglinski JW. Liver ischemia and reperfusion injury: new insights into mechanisms of innate-adaptive immune-mediated tissue inflammation. Am J Transplant 2011; 11:1563-9. [PMID: 21668640 PMCID: PMC3658307 DOI: 10.1111/j.1600-6143.2011.03579.x] [Citation(s) in RCA: 304] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Ischemia and reperfusion injury (IRI) is a dynamic process that involves two distinctive yet interrelated phases of ischemic organ damage and inflammation-mediated reperfusion injury. Although multiple cellular and molecular pathways contribute and regulate tissue/organ damage, integration of different players into a unified mechanism is warranted. The crosstalk between innate and adaptive immune systems plays a significant role in the pathogenesis of liver IRI. In this review, we focus on recent progress in the mechanism of liver innate immune activation by IR. Kupffer cells (KC), DCs, NK, as well as T cells initiate local inflammation response, the hallmark of IRI, by utilizing distinctive immune receptors to recognize and/or trigger various molecules, both endogenous and exogenous. The interlocked molecular signaling pathways in the context of multiple liver cell types, the IRI kinetics and positive versus negative regulatory loops in the innate immune activation process are discussed. Better appreciation of molecular interactions that mediate these intricate cascades, should allow for the development of novel therapeutic approached against IRI in liver transplant recipients.
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Affiliation(s)
- Y Zhai
- The Dumont-UCLA Transplantation Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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58
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Shalev I, Schmelzle M, Robson SC, Levy G. Making sense of regulatory T cell suppressive function. Semin Immunol 2011; 23:282-92. [PMID: 21592823 DOI: 10.1016/j.smim.2011.04.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 04/18/2011] [Indexed: 12/22/2022]
Abstract
Several types of regulatory T cells maintain self-tolerance and control excessive immune responses to foreign antigens. The major regulatory T subsets described over the past decade and novel function in transplantation will be covered in this review with a focus on CD4(+)CD25(+)Foxp3(+) regulatory T (Treg) cells. Multiple mechanisms have been proposed to explain how Treg cells inhibit effector cells but none can completely explain the observed effects in toto. Proposed mechanisms to explain suppressive activity of Treg cells include the generation of inhibitory cytokines, induced death of effector cells by cytokine deprivation or cytolysis, local metabolic perturbation of target cells mediated by changes in extracellular nucleotide/nucleoside fluxes with alterations in intracellular signaling molecules such as cyclic AMP, and finally inhibition of dendritic cell functions. A better understanding of how Treg cells operate at the molecular level could result in novel and safer therapeutic approaches in transplantation and immune-mediated diseases.
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Affiliation(s)
- Itay Shalev
- Multi-Organ Transplant Program, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario M5G 2N2, Canada
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59
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Abstract
Stimulation of almost all mammalian cell types leads to the release of cellular ATP and autocrine feedback through a diverse array of purinergic receptors. Depending on the types of purinergic receptors that are involved, autocrine signalling can promote or inhibit cell activation and fine-tune functional responses. Recent work has shown that autocrine signalling is an important checkpoint in immune cell activation and allows immune cells to adjust their functional responses based on the extracellular cues provided by their environment. This Review focuses on the roles of autocrine purinergic signalling in the regulation of both innate and adaptive immune responses and discusses the potential of targeting purinergic receptors for treating immune-mediated disease.
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60
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Fausther M, Sévigny J. Extracellular nucleosides and nucleotides regulate liver functions via a complex system of membrane proteins. C R Biol 2011; 334:100-17. [PMID: 21333941 DOI: 10.1016/j.crvi.2010.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 11/17/2010] [Accepted: 12/09/2010] [Indexed: 12/22/2022]
Abstract
Nucleosides and nucleotides are now considered as extracellular signalling molecules, like neurotransmitters and hormones. Hepatic cells, amongst other cells, ubiquitously express specific transmembrane receptors that transduce the physiological signals induced by extracellular nucleosides and nucleotides, as well as various cell surface enzymes that regulate the levels of these mediators in the extracellular medium. Here, we cover various aspects of the signalling pathways initiated by extracellular nucleosides and nucleotides in the liver, and discuss their overall impact on hepatic physiology.
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Affiliation(s)
- Michel Fausther
- Centre de recherche en rhumatologie et immunologie, CHU de Québec, QC, Canada
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61
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Deaglio S, Robson SC. Ectonucleotidases as regulators of purinergic signaling in thrombosis, inflammation, and immunity. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 61:301-32. [PMID: 21586363 PMCID: PMC5879773 DOI: 10.1016/b978-0-12-385526-8.00010-2] [Citation(s) in RCA: 192] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Evolving studies in models of transplant rejection, inflammatory bowel disease, and cancer, among others, have implicated purinergic signaling in clinical manifestations of vascular injury and thrombophilia, inflammation, and immune disturbance. Within the vasculature, spatial and temporal expression of CD39 nucleoside triphosphate diphosphohydrolase (NTPDase) family members together with CD73 ecto-5'-nucleotidase control platelet activation, thrombus size, and stability. This is achieved by closely regulated phosphohydrolytic activities to scavenge extracellular nucleotides, maintain P2-receptor integrity, and coordinate adenosinergic signaling responses. The CD38/CD157 family of extracellular NADases degrades NAD(+) and generates Ca(2+)-active metabolites, including cyclic ADP ribose and ADP ribose. These mediators regulate leukocyte adhesion and chemotaxis. These mechanisms are crucial in vascular homeostasis, hemostasis, thrombogenesis, and during inflammation. There has been recent interest in ectonucleotidase expression by immune cells. CD39 expression identifies Langerhans-type dendritic cells and efficiently distinguishes T regulatory cells from other resting or activated T cells. CD39, together with CD73 in mice, serves as an integral component of the suppressive machinery of T cells. Purinergic responses also impact generation of T helper-type 17 cells. Further, CD38 and changes in NAD(+) availability modulate ADP ribosylation of the cytolytic P2X7 receptor that deletes T regulatory cells. Expression of CD39, CD73, and CD38 ectonucleotidases on either endothelial or immune cells allows for homeostatic integration and control of vascular inflammatory and immune cell reactions at sites of injury. Ongoing development of therapeutic strategies targeting these and other ectonucleotidases offers promise for the management of vascular thrombosis, disordered inflammation, and aberrant immune reactivity.
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Affiliation(s)
- Silvia Deaglio
- Department of Genetics, Biology, and Biochemistry, University of Turin & Human Genetics Foundation, Italy
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