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Yee C, Main NM, Terry A, Stevanovski I, Maczurek A, Morgan AJ, Calabro S, Potter AJ, Iemma TL, Bowen DG, Ahlenstiel G, Warner FJ, McCaughan GW, McLennan SV, Shackel NA. CD147 mediates intrahepatic leukocyte aggregation and determines the extent of liver injury. PLoS One 2019; 14:e0215557. [PMID: 31291257 PMCID: PMC6619953 DOI: 10.1371/journal.pone.0215557] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/24/2019] [Indexed: 01/26/2023] Open
Abstract
Background Chronic inflammation is the driver of liver injury and results in progressive fibrosis and eventual cirrhosis with consequences including both liver failure and liver cancer. We have previously described increased expression of the highly multifunctional glycoprotein CD147 in liver injury. This work describes a novel role of CD147 in liver inflammation and the importance of leukocyte aggregates in determining the extent of liver injury. Methods Non-diseased, progressive injury, and cirrhotic liver from humans and mice were examined using a mAb targeting CD147. Inflammatory cell subsets were assessed by multiparameter flow cytometry. Results In liver injury, we observe abundant, intrahepatic leukocyte clusters defined as ≥5 adjacent CD45+ cells which we have termed “leukocyte aggregates”. We have shown that these leukocyte aggregates have a significant effect in determining the extent of liver injury. If CD147 is blocked in vivo, these leukocyte aggregates diminish in size and number, together with a marked significant reduction in liver injury including fibrosis. This is accompanied by no change in overall intrahepatic leukocyte numbers. Further, blocking of aggregation formation occurs prior to an appreciable increase in inflammatory markers or fibrosis. Additionally, there were no observed, “off-target” or unpredicted effects in targeting CD147. Conclusion CD147 mediates leukocyte aggregation which is associated with the development of liver injury. This is not a secondary effect, but a cause of injury as aggregate formation proceeds other markers of injury. Leukocyte aggregation has been previously described in inflammation dating back over many decades. Here we demonstrate that leukocyte aggregates determine the extent of liver injury.
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Affiliation(s)
- Christine Yee
- Centenary Institute of Cancer Medicine and Cell Biology, The University of Sydney, NSW, Australia
- Gastroenterology and Liver Laboratory, Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
| | - Nathan M. Main
- Gastroenterology and Liver Laboratory, Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
| | - Alexandra Terry
- Centenary Institute of Cancer Medicine and Cell Biology, The University of Sydney, NSW, Australia
- Gastroenterology and Liver Laboratory, Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
| | - Igor Stevanovski
- Gastroenterology and Liver Laboratory, Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
| | - Annette Maczurek
- Centenary Institute of Cancer Medicine and Cell Biology, The University of Sydney, NSW, Australia
| | - Alison J. Morgan
- Centenary Institute of Cancer Medicine and Cell Biology, The University of Sydney, NSW, Australia
| | - Sarah Calabro
- Centenary Institute of Cancer Medicine and Cell Biology, The University of Sydney, NSW, Australia
| | - Alison J. Potter
- Centenary Institute of Cancer Medicine and Cell Biology, The University of Sydney, NSW, Australia
| | - Tina L. Iemma
- Centenary Institute of Cancer Medicine and Cell Biology, The University of Sydney, NSW, Australia
| | - David G. Bowen
- Centenary Institute of Cancer Medicine and Cell Biology, The University of Sydney, NSW, Australia
- A.W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - Golo Ahlenstiel
- Western Sydney School of Medicine, Blacktown Hospital, Blacktown, NSW, Australia
| | - Fiona J. Warner
- Centenary Institute of Cancer Medicine and Cell Biology, The University of Sydney, NSW, Australia
| | - Geoffrey W. McCaughan
- Centenary Institute of Cancer Medicine and Cell Biology, The University of Sydney, NSW, Australia
- A.W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - Susan V. McLennan
- Department of Endocrinology, Department of Medicine and Bosch Institute, Royal Prince Alfred Hospital, The University of Sydney, NSW, Australia
| | - Nicholas A. Shackel
- Centenary Institute of Cancer Medicine and Cell Biology, The University of Sydney, NSW, Australia
- Gastroenterology and Liver Laboratory, Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
- A.W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
- Liverpool Hospital, Liverpool, NSW, Australia
- * E-mail:
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Lee A, Rode A, Nicoll A, Maczurek AE, Lim L, Lim S, Angus P, Kronborg I, Arachchi N, Gorelik A, Liew D, Warner FJ, McCaughan GW, McLennan SV, Shackel NA. Circulating CD147 predicts mortality in advanced hepatocellular carcinoma. J Gastroenterol Hepatol 2016; 31:459-66. [PMID: 26312403 DOI: 10.1111/jgh.13148] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 07/27/2015] [Accepted: 08/09/2015] [Indexed: 12/09/2022]
Abstract
BACKGROUND AND AIM The glycoprotein CD147 has a role in tumor progression, is readily detectable in the circulation, and is abundantly expressed in hepatocellular carcinoma (HCC). Advanced HCC patients are a heterogeneous group with some individuals having dismal survival. The aim of this study was to examine circulating soluble CD147 levels as a prognostic marker in HCC patients. METHODS CD147 was measured in 277 patients (110 HCC, 115 chronic liver disease, and 52 non-liver disease). Clinical data included etiology, tumor progression, Barcelona Clinic Liver Cancer (BCLC) stage, and treatment response. Patients with HCC were stratified into two groups based upon the 75th percentile of CD147 levels (24 ng/mL). RESULTS CD147 in HCC correlated inversely with poor survival (P = 0.031). Increased CD147 predicted poor survival in BCLC stages C and D (P = 0.045), and CD147 levels >24 ng/mL predicted a significantly diminished 90-day and 180-day survival time (hazard ratio [HR] = 6.1; 95% confidence interval [CI]: 2.1-63.2; P = 0.0045 and HR = 2.8; 95% CI: 1.2-12.6; P = 0.028, respectively). In BCLC stage C, CD147 predicted prognosis; levels >24 ng/mL were associated with a median survival of 1.5 months compared with 6.5 months with CD147 levels ≤24 ng/mL (P = 0.03). CD147 also identified patients with a poor prognosis independent from treatment frequency, modality, and tumor size. CONCLUSIONS Circulating CD147 is an independent marker of survival in advanced HCC. CD147 requires further evaluation as a potential new prognostic measure in HCC to identify patients with advanced disease who have a poor prognosis.
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Affiliation(s)
- Aimei Lee
- Centenary Institute of Cancer Medicine and Cell Biology, Camperdown, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
| | - Anthony Rode
- Department of Gastroenterology and Hepatology, Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - Amanda Nicoll
- Department of Gastroenterology and Hepatology, Box Hill Hospital, Box Hill, Victoria, Australia
| | - Annette E Maczurek
- Centenary Institute of Cancer Medicine and Cell Biology, Camperdown, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
| | - Lucy Lim
- Victorian Liver Transplant Unit and Department of Gastroenterology, Austin Hospital, Melbourne, Victoria, Australia
| | - Seok Lim
- Department of Gastroenterology and Hepatology, Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - Peter Angus
- Victorian Liver Transplant Unit and Department of Gastroenterology, Austin Hospital, Melbourne, Victoria, Australia
| | - Ian Kronborg
- Department of Gastroenterology, Western Hospital, Footscray, Victoria, Australia
| | - Niranjan Arachchi
- Department of Gastroenterology, Western Hospital, Footscray, Victoria, Australia
| | - Alexandra Gorelik
- Melbourne EpiCentre, University of Melbourne and Melbourne Health, Parkville, Victoria, Australia
| | - Danny Liew
- Melbourne EpiCentre, University of Melbourne and Melbourne Health, Parkville, Victoria, Australia
| | - Fiona J Warner
- Centenary Institute of Cancer Medicine and Cell Biology, Camperdown, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia
| | - Geoffrey W McCaughan
- Centenary Institute of Cancer Medicine and Cell Biology, Camperdown, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia.,A.W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - Susan V McLennan
- Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia.,Department of Endocrinology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - Nicholas A Shackel
- Centenary Institute of Cancer Medicine and Cell Biology, Camperdown, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Camperdown, New South Wales, Australia.,A.W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
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Tu T, Calabro SR, Lee A, Maczurek AE, Budzinska MA, Warner FJ, McLennan SV, Shackel NA. Hepatocytes in liver injury: Victim, bystander, or accomplice in progressive fibrosis? J Gastroenterol Hepatol 2015; 30:1696-704. [PMID: 26239824 DOI: 10.1111/jgh.13065] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 07/26/2015] [Indexed: 12/11/2022]
Abstract
Chronic liver disease causes significant morbidity and mortality through progressive fibrosis, cirrhosis, and liver cancer. The classical theory of fibrogenesis has hepatic stellate cells (HSCs) as the principal and only significant source of abnormal extracellular matrix (ECM). Further, HSCs have the major role in abnormal ECM turnover. It is the death of hepatocytes, as the initial target of injury, that initiates a sequence of events including the recruitment of inflammatory cells and activation of HSCs. Following this initial response, the ongoing insult to hepatocytes is regarded as perpetuating injury, but otherwise, hepatocytes are regarded as "victims" and "bystanders" in progressive fibrosis. Recent developments, however, challenge this view and suggest the concept of the hepatocyte being an active participant in liver injury. It is clear now that hepatocytes undergo phenotypic changes, adapt to injury, and react to the altered microenvironment. In this review, we describe studies showing that hepatocytes contribute to progressive fibrosis by direct manipulation of the surrounding ECM and through signaling to effector cells, particularly HSCs and intrahepatic immune cells. Together, these findings suggest an active "accomplice" role for the hepatocyte in progressive liver fibrosis and highlight novel pathways that could be targeted for development of future anti-fibrotic therapies.
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Affiliation(s)
- Thomas Tu
- Liver Injury and Cancer, Centenary Institute, Sydney, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Sarah R Calabro
- Liver Injury and Cancer, Centenary Institute, Sydney, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Aimei Lee
- Liver Injury and Cancer, Centenary Institute, Sydney, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Annette E Maczurek
- Liver Injury and Cancer, Centenary Institute, Sydney, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Magdalena A Budzinska
- Liver Injury and Cancer, Centenary Institute, Sydney, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Fiona J Warner
- Liver Injury and Cancer, Centenary Institute, Sydney, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Susan V McLennan
- Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.,Department of Endocrinology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Nicholas A Shackel
- Liver Injury and Cancer, Centenary Institute, Sydney, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.,A. W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
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Calabro SR, Maczurek AE, Morgan AJ, Tu T, Wen VW, Yee C, Mridha A, Lee M, d'Avigdor W, Locarnini SA, McCaughan GW, Warner FJ, McLennan SV, Shackel NA. Hepatocyte produced matrix metalloproteinases are regulated by CD147 in liver fibrogenesis. PLoS One 2014; 9:e90571. [PMID: 25076423 PMCID: PMC4116334 DOI: 10.1371/journal.pone.0090571] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 02/02/2014] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The classical paradigm of liver injury asserts that hepatic stellate cells (HSC) produce, remodel and turnover the abnormal extracellular matrix (ECM) of fibrosis via matrix metalloproteinases (MMPs). In extrahepatic tissues MMP production is regulated by a number of mechanisms including expression of the glycoprotein CD147. Previously, we have shown that CD147 is expressed on hepatocytes but not within the fibrotic septa in cirrhosis [1]. Therefore, we investigated if hepatocytes produce MMPs, regulated by CD147, which are capable of remodelling fibrotic ECM independent of the HSC. METHODS Non-diseased, fibrotic and cirrhotic livers were examined for MMP activity and markers of fibrosis in humans and mice. CD147 expression and MMP activity were co-localised by in-situ zymography. The role of CD147 was studied in-vitro with siRNA to CD147 in hepatocytes and in-vivo in mice with CCl4 induced liver injury using ãCD147 antibody intervention. RESULTS In liver fibrosis in both human and mouse tissue MMP expression and activity (MMP-2, -9, -13 and -14) increased with progressive injury and localised to hepatocytes. Additionally, as expected, MMPs were abundantly expressed by activated HSC. Further, with progressive fibrosis there was expression of CD147, which localised to hepatocytes but not to HSC. Functionally significant in-vitro regulation of hepatocyte MMP production by CD147 was demonstrated using siRNA to CD147 that decreased hepatocyte MMP-2 and -9 expression/activity. Further, in-vivo α-CD147 antibody intervention decreased liver MMP-2, -9, -13, -14, TGF-β and α-SMA expression in CCl4 treated mice compared to controls. CONCLUSION We have shown that hepatocytes produce active MMPs and that the glycoprotein CD147 regulates hepatocyte MMP expression. Targeting CD147 regulates hepatocyte MMP production both in-vitro and in-vivo, with the net result being reduced fibrotic matrix turnover in-vivo. Therefore, CD147 regulation of hepatocyte MMP is a novel pathway that could be targeted by future anti-fibrogenic agents.
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Affiliation(s)
- Sarah R. Calabro
- Liver Cell Biology, Centenary Institute, Sydney, NSW, Australia
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Annette E. Maczurek
- Liver Cell Biology, Centenary Institute, Sydney, NSW, Australia
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Alison J. Morgan
- Liver Cell Biology, Centenary Institute, Sydney, NSW, Australia
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Thomas Tu
- Liver Cell Biology, Centenary Institute, Sydney, NSW, Australia
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Victoria W. Wen
- Liver Cell Biology, Centenary Institute, Sydney, NSW, Australia
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Christine Yee
- Liver Cell Biology, Centenary Institute, Sydney, NSW, Australia
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Auvro Mridha
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Maggie Lee
- Liver Cell Biology, Centenary Institute, Sydney, NSW, Australia
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - William d'Avigdor
- Liver Cell Biology, Centenary Institute, Sydney, NSW, Australia
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | | | - Geoffrey W. McCaughan
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
- A.W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Camperdown, Sydney, NSW, Australia
- Liver Injury and Cancer, Centenary Institute, Sydney, NSW, Australia
| | - Fiona J. Warner
- Liver Cell Biology, Centenary Institute, Sydney, NSW, Australia
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Susan V. McLennan
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
- Department of Endocrinology, Royal Prince Alfred Hospital, Camperdown, Sydney, NSW, Australia
| | - Nicholas A. Shackel
- Liver Cell Biology, Centenary Institute, Sydney, NSW, Australia
- Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
- A.W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Camperdown, Sydney, NSW, Australia
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5
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Tu T, Budzinska MA, Maczurek AE, Cheng R, Di Bartolomeo A, Warner FJ, McCaughan GW, McLennan SV, Shackel NA. Novel aspects of the liver microenvironment in hepatocellular carcinoma pathogenesis and development. Int J Mol Sci 2014; 15:9422-58. [PMID: 24871369 PMCID: PMC4100103 DOI: 10.3390/ijms15069422] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 05/13/2014] [Accepted: 05/14/2014] [Indexed: 12/12/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is a prevalent primary liver cancer that is derived from hepatocytes and is characterised by high mortality rate and poor prognosis. While HCC is driven by cumulative changes in the hepatocyte genome, it is increasingly recognised that the liver microenvironment plays a pivotal role in HCC propensity, progression and treatment response. The microenvironmental stimuli that have been recognised as being involved in HCC pathogenesis are diverse and include intrahepatic cell subpopulations, such as immune and stellate cells, pathogens, such as hepatitis viruses, and non-cellular factors, such as abnormal extracellular matrix (ECM) and tissue hypoxia. Recently, a number of novel environmental influences have been shown to have an equally dramatic, but previously unrecognized, role in HCC progression. Novel aspects, including diet, gastrointestinal tract (GIT) microflora and circulating microvesicles, are now being recognized as increasingly important in HCC pathogenesis. This review will outline aspects of the HCC microenvironment, including the potential role of GIT microflora and microvesicles, in providing new insights into tumourigenesis and identifying potential novel targets in the treatment of HCC.
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Affiliation(s)
- Thomas Tu
- Liver Cell Biology, Centenary Institute, Sydney, NSW 2050, Australia.
| | | | | | - Robert Cheng
- Liver Cell Biology, Centenary Institute, Sydney, NSW 2050, Australia.
| | - Anna Di Bartolomeo
- School of Medicine, University of Adelaide, Adelaide, SA 5005, Australia.
| | - Fiona J Warner
- Liver Cell Biology, Centenary Institute, Sydney, NSW 2050, Australia.
| | | | - Susan V McLennan
- Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia.
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Rahman W, Huang P, Belov L, Chrisp JS, Christopherson RI, Stapelberg PM, Warner FJ, George J, Bowen DG, Strasser SI, Koorey D, Sharland AF, McCaughan GW, Shackel NA. Analysis of human liver disease using a cluster of differentiation (CD) antibody microarray. Liver Int 2012; 32:1527-34. [PMID: 22863037 DOI: 10.1111/j.1478-3231.2012.02854.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 06/17/2012] [Accepted: 06/27/2012] [Indexed: 02/13/2023]
Abstract
BACKGROUND A CD antibody microarray has been previously developed allowing semi-quantitative identification of greater than 80 CD antigens on circulating leucocytes from peripheral blood samples. This assay, which uses a live cell-capture technique, enables an extensive leucocyte immunophenotype determination in a single analysis and to date this has been used successfully to characterise diseases including human leukaemias and HIV infection. AIMS To determine CD antigen expression profiles for patients with various liver diseases and to look for preserved disease-specific signatures. METHODS Three liver disease groups including hepatitis C (HCV) (n = 35), non-alcoholic steatohepatitis (NASH) (n = 21) and alcohol-related liver disease (n = 14) were compared with a normal group (n = 23). Hierarchal Clustering (HCL) and Principal Component Analysis (PCA) of the data revealed distinct binding patterns for patients with and without cirrhosis. RESULTS Patients with cirrhosis and portal hypertension compared with those without cirrhosis had significantly reduced expression of several markers of T-cell function including CD45, CD8, CD28 and TCR α/β. Disease prediction algorithms based on the expression data were able to discriminate cirrhotics from non-cirrhotics with 71% overall success, which improved to 77% when only patients with HCV were considered. CONCLUSIONS These results demonstrate disease-specific consensus patterns of expression of CD antigens for patients with chronic liver disease, suggesting that the CD antibody array is a promising tool in the analysis of human liver disease, and with further refinement may have future research and clinical utility.
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Affiliation(s)
- Wassim Rahman
- A.W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Sydney, NSW, Australia
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Smith NJ, Chan HW, Qian H, Bourne AM, Hannan KM, Warner FJ, Ritchie RH, Pearson RB, Hannan RD, Thomas WG. Determination of the Exact Molecular Requirements for Type 1 Angiotensin Receptor Epidermal Growth Factor Receptor Transactivation and Cardiomyocyte Hypertrophy. Hypertension 2011; 57:973-80. [DOI: 10.1161/hypertensionaha.110.166710] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Nicola J. Smith
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Hsiu-Wen Chan
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Hongwei Qian
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Allison M. Bourne
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Katherine M. Hannan
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Fiona J. Warner
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Rebecca H. Ritchie
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Richard B. Pearson
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Ross D. Hannan
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Walter G. Thomas
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
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Bao W, Min D, Twigg SM, Shackel NA, Warner FJ, Yue DK, McLennan SV. Monocyte CD147 is induced by advanced glycation end products and high glucose concentration: possible role in diabetic complications. Am J Physiol Cell Physiol 2010; 299:C1212-9. [PMID: 20810913 DOI: 10.1152/ajpcell.00228.2010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
CD147 is a highly glycosylated transmembrane protein that is known to play a role in regulation of many protein families. It has the unique ability to maintain functional activity in both the membrane bound state and in the soluble form. CD147 is known to play a role in regulation of matrix metalloproteinase (MMP) expression, but whether its expression is affected by the diabetic milieu is not known, and its role in regulation of monocyte MMPs in this environment has not been investigated. Therefore, in this study we investigated the effect of advanced glycation end products (AGEs) and high glucose (HG; 25 mM), on monocyte CD147 expression. Culture of THP-1 monocytes in the presence of AGEs or HG significantly increased CD147 at the gene and protein level. THP-1 cell results were confirmed using freshly isolated monocytes from human volunteers. The effect of AGEs and HG on CD147 expression was also mimicked by addition of proinflammatory cytokines. Addition of AGEs or HG also increased expression of monocyte MMP-1 and MMP-9 but not MMP-2. This increase in MMPs was significantly attenuated by inhibition of CD147 using either a small interfering RNA or an anti-CD147 antibody. Inhibition of NF-κB or addition of antibodies to either TNF-α or the receptor for AGE (RAGE) each significantly prevented in a dose-dependent manner the induction of CD147 gene and protein by AGE and also decreased MMP-1 and MMP-9. This novel result shows that AGEs can induce monocyte CD147 expression, an effect mediated by inflammatory pathways and RAGE. Because MMPs play a role in monocyte migration, inhibition of their regulator CD147 may assist in the prevention of diabetic complications, particularly those where monocyte infiltration is an early initiating event.
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Affiliation(s)
- W Bao
- Discipline of Medicine and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
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10
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Velkoska E, Warner FJ, Cole TJ, Smith I, Morris MJ. Metabolic effects of low dose angiotensin converting enzyme inhibitor in dietary obesity in the rat. Nutr Metab Cardiovasc Dis 2010; 20:49-55. [PMID: 19361967 DOI: 10.1016/j.numecd.2009.02.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 02/10/2009] [Accepted: 02/10/2009] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND AIMS Given the recent observation of a local renin-angiotensin system (RAS) in adipose tissue, and its association with obesity-related hypertension, the metabolic effects of treatment with a low dose angiotensin converting enzyme inhibitor (ACEI) were investigated in a rodent model of diet-induced obesity. METHODS AND RESULTS Male Sprague Dawley rats were exposed to either standard laboratory chow (12% calories as fat) or palatable high fat (30% calories as fat) diet for 12 weeks. A subset from both dietary groups was given low dose ACEI in drinking water (perindopril, 0.3 mg/kg/day) throughout the study. The high fat diet increased body weight, adiposity, circulating leptin and insulin and in the liver we observed fat accumulation and increased tissue ACE activity. Treatment with perindopril decreased food intake and circulating insulin in both diet groups, and hepatic ACE activity in high fat fed animals only. Decreased plasma leptin concentration with ACE inhibition was only evident in chow fed animals. These effects were independent of any blood pressure lowering effect of ACE inhibition. CONCLUSION Chronic low dose ACEI treatment reduced circulating insulin and leptin levels with some reduction in food intake in chow fed rats. Fewer beneficial effects were observed in obesity, and further work is required to investigate higher ACEI doses. Our data suggest a reduction in hepatic ACE activity may affect lipid accumulation and other inflammatory responses, as well as improving insulin resistance. Our findings may have implications for maximizing the clinical benefit of ACEI in patients without overt cardiovascular complications.
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Affiliation(s)
- E Velkoska
- Department of Pharmacology, The University of Melbourne, Parkville, Victoria 3010, Australia
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11
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Abstract
The contribution of bone marrow stem cell responses to liver homeostasis, injury and malignancy is discussed in this review. Pluripotent stem cells or their more committed progenitor progeny are essential to tissue development, regeneration and repair and are widely implicated in the pathogenesis of malignancy. Stem cell responses to injury are the focus of intense research efforts in the hope of future therapeutic manipulation. Stem cells occur within tissues, such as the liver, or arise from extrahepatic sites, in particular, the bone marrow. As the largest reservoir of stem cells in the adult, the bone marrow has been implicated in the stem cell response associated with liver injury. However, in liver injury, the relative contribution of bone marrow stem cells compared to intrahepatic progenitor responses is poorly characterized. Intrahepatic progenitor responses have been recently reviewed elsewhere. In this review, we have summarized liver-specific extrahepatic stem cell responses originating from the bone marrow. The physiological relevance of bone marrow stem cell responses to adult liver homeostasis, injury and malignancy is discussed with emphasis on mechanisms of bone marrow stem cell recruitment to sites of liver injury and its contribution to intrahepatic malignancy.
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Shackel NA, McCaughan GW, Warner FJ. Hepatocellular carcinoma development requires hepatic stem cells with altered transforming growth factor and interleukin-6 signaling. Hepatology 2008; 47:2134-6. [PMID: 18508299 DOI: 10.1002/hep.22369] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Affiliation(s)
- Nicholas A Shackel
- Central Clinical School and Faculty of Medicine, Centenary Institute, University of Sydney, Camperdown, New South Wales, Australia
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Lew RA, Warner FJ, Hanchapola I, Yarski MA, Ramchand J, Manohar J, Burrell LM, Smith AI. Angiotensin-converting enzyme 2 catalytic activity in human plasma is masked by an endogenous inhibitor. Exp Physiol 2008; 93:685-93. [PMID: 18223027 PMCID: PMC7197901 DOI: 10.1113/expphysiol.2007.040352] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2007] [Accepted: 01/09/2008] [Indexed: 12/16/2022]
Abstract
Angiotensin-converting enzyme 2 (ACE2) is thought to act in an opposing manner to its homologue, angiotensin-converting enzyme (ACE), by inactivating the vasoconstrictor peptide angiotensin II and generating the vasodilatory fragment, angiotensin(1-7). Both ACE and ACE2 are membrane-bound ectoenzymes and may circulate in plasma as a consequence of a proteolytic shedding event. In this study, we show that ACE2 circulates in human plasma, but its activity is suppressed by the presence of an endogenous inhibitor. Partial purification of this inhibitor indicated that the inhibitor is small, hydrophilic and cationic, but not a divalent metal cation. These observations led us to develop a method for removal of the inhibitor, thus allowing detection of plasma ACE2 levels using a sensitive quenched fluorescent substrate-based assay. Using this technique, ACE2 activity measured in plasma from healthy volunteers (n = 18) ranged from 1.31 to 8.69 pmol substrate cleaved min-1 ml-1 (mean +/- s.e.m., 4.44 +/- 0.56 pmol min-1 ml-1). Future studies of patients with cardiovascular, renal and liver disease will determine whether plasma ACE2 is elevated in parallel with increased tissue levels observed in these conditions.
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Affiliation(s)
- Rebecca A Lew
- Department of Biochemistry & Molecular Biology, PO Box 13D, Monash University, Clayton, Victoria 3800, Australia
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Affiliation(s)
- Nicholas A Shackel
- Centenary Institute, Faculty of Medicine, The University of Sydney, Camperdown, Royal Prince Alfred Hospital, Camperdown, Sydney Australia
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Burcher E, Shang F, Warner FJ, Du Q, Lubowski DZ, King DW, Liu L. Tachykinin NK2 Receptor and Functional Mechanisms in Human Colon: Changes with Indomethacin and in Diverticular Disease and Ulcerative Colitis. J Pharmacol Exp Ther 2007; 324:170-8. [DOI: 10.1124/jpet.107.130385] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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Herath CB, Warner FJ, Lubel JS, Dean RG, Jia Z, Lew RA, Smith AI, Burrell LM, Angus PW. Upregulation of hepatic angiotensin-converting enzyme 2 (ACE2) and angiotensin-(1-7) levels in experimental biliary fibrosis. J Hepatol 2007. [PMID: 17532087 DOI: 10.1016/j.jhep.2007.03.008]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND/AIMS Angiotensin-converting enzyme 2 (ACE2), its product, angiotensin-(1-7) and its receptor, Mas, may moderate the adverse effects of angiotensin II in liver disease. We examined the expression of these novel components of the renin angiotensin system (RAS) and the production and vasoactive effects of angiotensin-(1-7) in the bile duct ligated (BDL) rat. METHODS BDL or sham-operated rats were sacrificed at 1, 2, 3 and 4 weeks. Tissue and blood were collected for gene expression, enzyme activity and peptide measurements. In situ perfused livers were used to assess angiotensin peptide production and their effects on portal resistance. RESULTS Hepatic ACE2 gene and activity (P<0.0005), plasma angiotensin-(1-7) (P<0.0005) and Mas receptor expression (P<0.01) were increased following BDL compared to shams. Perfusion experiments confirmed that BDL livers produced increased angiotensin-(1-7) (P<0.05) from angiotensin II and this was augmented (P<0.01) by ACE inhibition. Whilst angiotensin II increased vasoconstriction in cirrhotic livers, angiotensin-(1-7) had no effect on portal resistance. CONCLUSIONS RAS activation in chronic liver injury is associated with upregulation of ACE2, Mas and hepatic conversion of angiotensin II to angiotensin-(1-7) leading to increased circulating angiotensin-(1-7). These results support the presence of an ACE2-angiotensin-(1-7)-Mas axis in liver injury which may counteract the effects of angiotensin II.
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Affiliation(s)
- Chandana B Herath
- Department of Medicine, The University of Melbourne, Austin Health, Heidelberg, Vic., Australia
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17
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Herath CB, Warner FJ, Lubel JS, Dean RG, Jia Z, Lew RA, Smith AI, Burrell LM, Angus PW. Upregulation of hepatic angiotensin-converting enzyme 2 (ACE2) and angiotensin-(1-7) levels in experimental biliary fibrosis. J Hepatol 2007; 47:387-95. [PMID: 17532087 PMCID: PMC7114685 DOI: 10.1016/j.jhep.2007.03.008] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Revised: 02/09/2007] [Accepted: 03/05/2007] [Indexed: 12/12/2022]
Abstract
BACKGROUND/AIMS Angiotensin-converting enzyme 2 (ACE2), its product, angiotensin-(1-7) and its receptor, Mas, may moderate the adverse effects of angiotensin II in liver disease. We examined the expression of these novel components of the renin angiotensin system (RAS) and the production and vasoactive effects of angiotensin-(1-7) in the bile duct ligated (BDL) rat. METHODS BDL or sham-operated rats were sacrificed at 1, 2, 3 and 4 weeks. Tissue and blood were collected for gene expression, enzyme activity and peptide measurements. In situ perfused livers were used to assess angiotensin peptide production and their effects on portal resistance. RESULTS Hepatic ACE2 gene and activity (P<0.0005), plasma angiotensin-(1-7) (P<0.0005) and Mas receptor expression (P<0.01) were increased following BDL compared to shams. Perfusion experiments confirmed that BDL livers produced increased angiotensin-(1-7) (P<0.05) from angiotensin II and this was augmented (P<0.01) by ACE inhibition. Whilst angiotensin II increased vasoconstriction in cirrhotic livers, angiotensin-(1-7) had no effect on portal resistance. CONCLUSIONS RAS activation in chronic liver injury is associated with upregulation of ACE2, Mas and hepatic conversion of angiotensin II to angiotensin-(1-7) leading to increased circulating angiotensin-(1-7). These results support the presence of an ACE2-angiotensin-(1-7)-Mas axis in liver injury which may counteract the effects of angiotensin II.
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Affiliation(s)
- Chandana B Herath
- Department of Medicine, The University of Melbourne, Austin Health, Heidelberg, Vic., Australia
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Abstract
There is an increasing body of evidence to suggest that the RAS (renin–angiotensin system) contributes to tissue injury and fibrosis in chronic liver disease. A number of studies have shown that components of a local hepatic RAS are up-regulated in fibrotic livers of humans and in experimental animal models. Angiotensin II, the main physiological effector molecule of this system, mediates liver fibrosis by stimulating fibroblast proliferation (myofibroblast and hepatic stellate cells), infiltration of inflammatory cells, and the release of inflammatory cytokines and growth factors such as TGF (transforming growth factor)-β1, IL (interleukin)-1β, MCP (monocyte chemoattractant protein)-1 and connective tissue growth factor. Furthermore, blockade of the RAS by ACE (angiotensin-converting enzyme) inhibitors and angiotensin type 1 receptor antagonists significantly attenuate liver fibrosis in experimental models of chronic liver injury. In 2000 ACE2 (angiotensin-converting enzyme 2), a human homologue of ACE, was identified. ACE2 efficiently degrades angiotensin II to angiotensin-(1–7), a peptide which has recently been shown to have both vasodilatory and tissue protective effects. This suggests that ACE2 and its products may be part of an alternate enzymatic pathway in the RAS, which counterbalances the generation and actions of angiotensin II, the ACE2–angiotensin-(1–7)–Mas axis. This review focuses on the potential roles of the RAS, angiotensin II and ACE2 in chronic liver injury and fibrogenesis.
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Affiliation(s)
- Fiona J Warner
- A. W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
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19
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Affiliation(s)
- Michael R Beard
- School of Molecular and Biomedical Science, The University of Adelaide, SA, Australia
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Affiliation(s)
- Fiona J Warner
- Centenary Institute, Faculty of Medicine, University of Sydney, Sydney, NSW, Australia
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Affiliation(s)
- Mark D Gorrell
- Centenary Institute, University of Sydney, Sydney, Australia
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22
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Abstract
Angiotensin converting enzyme-2 (ACE2) is a recently described membrane-bound carboxypeptidase identified by its homology to ACE, the enzyme responsible for the formation of the potent vasoconstrictor angiotensin II (Ang II). ACE2 inactivates Ang II and is thus thought to act in a counter-regulatory fashion to ACE. ACE2 is highly expressed in epithelial cells of distal renal tubules, and recent evidence indicates that expression is increased in a range of renal diseases. A soluble form of ACE, generated by proteolytic cleavage of the membrane-bound form, has been shown to be present in urine; although evidence for a similar release of ACE2 has been reported in cell culture, it is not yet known whether this occurs in vivo. The present study has identified ACE2 in human urine, both by a sensitive fluorescence-based activity assay and by Western immunoblot. Levels of ACE2 were surprisingly higher than ACE, which may reflect preferential targeting of the enzyme to the luminal surface of the renal epithelium. Future studies will determine whether increased expression of ACE2 in renal diseases are reflected in higher urinary levels of this novel enzyme.
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Affiliation(s)
- Rebecca A Lew
- 1Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria Australia.,2Department of Biochemistry and Molecular Biology, Monash University, PO Box 13D, Clayton, Victoria 3800 Australia
| | - Fiona J Warner
- 1Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria Australia
| | - Iresha Hanchapola
- 1Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria Australia
| | - A Ian Smith
- 1Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria Australia
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Paizis G, Tikellis C, Cooper ME, Schembri JM, Lew RA, Smith AI, Shaw T, Warner FJ, Zuilli A, Burrell LM, Angus PW. Chronic liver injury in rats and humans upregulates the novel enzyme angiotensin converting enzyme 2. Gut 2005; 54:1790-6. [PMID: 16166274 PMCID: PMC1774784 DOI: 10.1136/gut.2004.062398] [Citation(s) in RCA: 249] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Angiotensin converting enzyme (ACE) 2 is a recently identified homologue of ACE that may counterregulate the actions of angiotensin (Ang) II by facilitating its breakdown to Ang 1-7. The renin-angiotensin system (RAS) has been implicated in the pathogenesis of cirrhosis but the role of ACE2 in liver disease is not known. AIMS This study examined the effects of liver injury on ACE2 expression and activity in experimental hepatic fibrosis and human cirrhosis, and the effects of Ang 1-7 on vascular tone in cirrhotic rat aorta. METHODS In sham operated and bile duct ligated (BDL) rats, quantitative reverse transcriptase-polymerase chain reaction was used to assess hepatic ACE2 mRNA, and western blotting and immunohistochemistry to quantify and localise ACE2 protein. ACE2 activity was quantified by quenched fluorescent substrate assay. Similar studies were performed in normal human liver and in hepatitis C cirrhosis. RESULTS ACE2 mRNA was detectable at low levels in rat liver and increased following BDL (363-fold; p < 0.01). ACE2 protein increased after BDL (23.5-fold; p < 0.05) as did ACE2 activity (fourfold; p < 0.05). In human cirrhotic liver, gene (>30-fold), protein expression (97-fold), and activity of ACE2 (2.4 fold) were increased compared with controls (all p < 0.01). In healthy livers, ACE2 was confined to endothelial cells, occasional bile ducts, and perivenular hepatocytes but in both BDL and human cirrhosis there was widespread parenchymal expression of ACE2 protein. Exposure of cultured human hepatocytes to hypoxia led to increased ACE2 expression. In preconstricted rat aorta, Ang 1-7 alone did not affect vascular tone but it significantly enhanced acetylcholine mediated vasodilatation in cirrhotic vessels. CONCLUSIONS ACE2 expression is significantly increased in liver injury in both humans and rat, possibly in response to increasing hepatocellular hypoxia, and may modulate RAS activity in cirrhosis.
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Affiliation(s)
- G Paizis
- University of Melbourne, Department of Medicine, Austin Health, Heidelberg, Victoria, Australia
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Warner FJ, Lew RA, Smith AI, Lambert DW, Hooper NM, Turner AJ. Angiotensin-converting enzyme 2 (ACE2), but not ACE, is preferentially localized to the apical surface of polarized kidney cells. J Biol Chem 2005; 280:39353-62. [PMID: 16166094 DOI: 10.1074/jbc.m508914200] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Angiotensin-converting enzyme-2 (ACE2) is a homologue of angiotensin-I converting enzyme (ACE), the central enzyme of the renin-angiotensin system (RAS). ACE2 is abundant in human kidney and heart and has been implicated in renal and cardiac function through its ability to hydrolyze Angiotensin II. Although ACE2 and ACE are both type I integral membrane proteins and share 61% protein sequence similarity, they display distinct modes of enzyme action and tissue distribution. This study characterized ACE2 at the plasma membrane of non-polarized Chinese hamster ovary (CHO) cells and polarized Madin-Darby canine kidney (MDCKII) epithelial cells and compared its cellular localization to its related enzyme, ACE, using indirect immunofluorescence, cell-surface biotinylation, Western analysis, and enzyme activity assays. This study shows ACE2 and ACE are both cell-surface proteins distributed evenly to detergent-soluble regions of the plasma membrane in CHO cells. However, in polarized MDCKII cells under steady-state conditions the two enzymes are differentially expressed. ACE2 is localized predominantly to the apical surface ( approximately 92%) where it is proteolytically cleaved within its ectodomain to release a soluble form. Comparatively, ACE is present on both the apical ( approximately 55%) and basolateral membranes ( approximately 45%) where it is also secreted but differentially; the ectodomain cleavage of ACE is 2.5-fold greater from the apical surface than the basolateral surface. These studies suggest that both ACE2 and ACE are ectoenzymes that have distinct localization and secretion patterns that determine their role on the cell surface in kidney epithelium and in urine.
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Affiliation(s)
- Fiona J Warner
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, United Kingdom
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Lambert DW, Yarski M, Warner FJ, Thornhill P, Parkin ET, Smith AI, Hooper NM, Turner AJ. Tumor necrosis factor-alpha convertase (ADAM17) mediates regulated ectodomain shedding of the severe-acute respiratory syndrome-coronavirus (SARS-CoV) receptor, angiotensin-converting enzyme-2 (ACE2). J Biol Chem 2005; 280:30113-9. [PMID: 15983030 PMCID: PMC8062222 DOI: 10.1074/jbc.m505111200] [Citation(s) in RCA: 536] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 06/24/2005] [Indexed: 01/11/2023] Open
Abstract
Angiotensin-converting enzyme-2 (ACE2) is a critical regulator of heart function and a cellular receptor for the causative agent of severe-acute respiratory syndrome (SARS), SARS-CoV (coronavirus). ACE2 is a type I transmembrane protein, with an extracellular N-terminal domain containing the active site and a short intracellular C-terminal tail. A soluble form of ACE2, lacking its cytosolic and transmembrane domains, has been shown to block binding of the SARS-CoV spike protein to its receptor. In this study, we examined the ability of ACE2 to undergo proteolytic shedding and investigated the mechanisms responsible for this shedding event. We demonstrated that ACE2, heterologously expressed in HEK293 cells and endogenously expressed in Huh7 cells, undergoes metalloproteinase-mediated, phorbol ester-inducible ectodomain shedding. By using inhibitors with differing potency toward different members of the ADAM (a disintegrin and metalloproteinase) family of proteases, we identified ADAM17 as a candidate mediator of stimulated ACE2 shedding. Furthermore, ablation of ADAM17 expression using specific small interfering RNA duplexes reduced regulated ACE2 shedding, whereas overexpression of ADAM17 significantly increased shedding. Taken together, these data provided direct evidence for the involvement of ADAM17 in the regulated ectodomain shedding of ACE2. The identification of ADAM17 as the protease responsible for ACE2 shedding may provide new insight into the physiological roles of ACE2.
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Affiliation(s)
- Daniel W Lambert
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, United Kingdom.
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Abstract
Angiotensin-converting enzyme-2 (ACE2) is the first human homologue of ACE to be described. ACE2 is a type I integral membrane protein which functions as a carboxypeptidase, cleaving a single hydrophobic/basic residue from the C-terminus of its substrates. ACE2 efficiently hydrolyses the potent vasoconstrictor angiotensin II to angiotensin (1–7). It is a consequence of this action that ACE2 participates in the renin-angiotensin system. However, ACE2 also hydrolyses dynorphin A (1–13), apelin-13 and des-Arg9 bradykinin. The role of ACE2 in these peptide systems has yet to be revealed. A physiological role for ACE2 has been implicated in hypertension, cardiac function, heart function and diabetes, and as a receptor of the severe acute respiratory syndrome coronavirus. This paper reviews the biochemistry of ACE2 and discusses key findings such as the elucidation of crystal structures for ACE2 and testicular ACE and the development of ACE2 inhibitors that have now provided a basis for future research on this enzyme.
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Affiliation(s)
- F J Warner
- School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, United Kingdom.
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Abstract
1. The present study compared the binding and functional characteristics of tachykinin NK2 receptors in human detrusor muscle with those in human colon circular muscle. 2. In radioligand binding studies, similar KD values were observed for tachykinin NK2 receptor radioligands [125I]-neurokinin (NK) A, [125I]-[Lys5,Tyr(I2)7,MeLeu9,Nle10,]NKA(4-10) and [3H]-SR48968 in both human colon circular muscle (0.28-1.1 nmol/L) and human bladder detrusor (0.49-0.91 nmol/L), suggesting binding was primarily to tachykinin NK2 receptors. Receptor capacity (Bmax) was greater in colon compared with detrusor muscle. 3. In functional studies of isolated smooth muscle contraction, there was an excellent positive correlation between human bladder detrusor and colon circular muscle with respect to in vitro contractile potency (r = 0.97) and maximum responses (r = 0.98) to tachykinins, selective tachykinin receptor ligands and l-Ala-substituted NKA(4-10) analogues. 4. Species differences between the human and rat tachykinin NK2 receptors were apparent as observed by a low correlation for potency (r = 0.77) and efficacy (r = 0.32) of l-Ala-substituted analogues in isolated smooth muscle contractile studies. 5. Minor differences observed in the affinity and potency of NK2 receptor agonists between colon and bladder are dependent on the tissue of interest, the receptor-effector coupling and the presence of other tachykinin receptors. Overall, the NK2 receptors of human colon and urinary bladder smooth muscle appear pharmacologically identical.
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Affiliation(s)
- Fiona J Warner
- School of Physiology and Pharmacology, University of New South Wales, Sydney, New South Wales, Australia.
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Warner FJ, Guy JL, Lambert DW, Hooper NM, Turner AJ. Angiotensin Converting Enzyme-2 (ACE2) and its Possible Roles in Hypertension, Diabetes and Cardiac Function. Lett Pept Sci 2003; 10:377-385. [PMID: 32214681 PMCID: PMC7088140 DOI: 10.1007/s10989-004-2387-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Angiotensin converting enzyme-2 (ACE2) is a recently described homologue of the vasoactive peptidase, angiotensin converting enzyme (ACE). Like ACE, ACE2 is an integral (type I) membrane zinc metallopeptidase, which exists as an ectoenzyme. ACE2 is less widely distributed than ACE in the body, being expressed at highest concentrations in the heart, kidney and testis. ACE2 also differs from ACE in its substrate specificity, functioning exclusively as a carboxypeptidase rather than a peptidyl dipeptidase. A key role for ACE2 appears to be emerging in the conversion of angiotensin II to angiotensin (1-7), allowing it to act as a counter-balance to the actions of ACE. ACE2 has been localised to the endothelial and epithelial cells of the heart and kidney where it may have a role at the cell surface in hydrolysing bioactive peptides such as angiotensin II present in the circulation. A role for ACE2 in the metabolism of other biologically active peptides also needs to be considered. ACE2 also serendipitously appears to act as a receptor for the severe acute respiratory syndrome (SARS) coronavirus. Studies using ace2 -/- mice, and other emerging studies in vivo and in vitro, have revealed that ACE2 has important functions in cardiac regulation and diabetes. Together with its role as a SARS receptor, ACE2 is therefore likely to be an important therapeutic target in a diverse range of disease states.
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Affiliation(s)
- Fiona J. Warner
- Baker Heart Research Institute, Peptide Biology, Melbourne, Victoria 3004 Australia
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, Leeds, LS2 9JT UK
| | - Jodie L. Guy
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, Leeds, LS2 9JT UK
| | - Dan W. Lambert
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, Leeds, LS2 9JT UK
| | - Nigel M. Hooper
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, Leeds, LS2 9JT UK
| | - Anthony J. Turner
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, Leeds, LS2 9JT UK
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Warner FJ, Guy JL, Lambert DW, Hooper NM, Turner AJ. Angiotensin converting enzyme-2 (ACE2) and its possible roles in hypertension, diabetes and cardiac function. Lett Pept Sci 2003; 10:377-385. [PMID: 32214680 PMCID: PMC7087859 DOI: 10.1007/bf02442567] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Accepted: 03/18/2004] [Indexed: 01/12/2023]
Abstract
Angiotensin converting enzyme-2 (ACE2) is a recently described homologue of the vasoactive peptidase, angiotensin converting enzyme (ACE). Like ACE, ACE2 is an integral (type I) membrane zinc metallopeptidase, which exists as an ectoenzyme. ACE2 is less widely distributed than ACE in the body, being expressed at highest concentrations in the heart, kidney and testis. ACE2 also differs from ACE in its substrate specificity, functioning exclusively as a carboxypeptidase rather than a peptidyl dipeptidase. A key role for ACE2 appears to be emerging in the conversion of angiotensin II to angiotensin (1-7), allowing it to act as a counter-balance to the actions of ACE. ACE2 has been localised to the endothelial and epithelial cells of the heart and kidney where it may have a role at the cell surface in hydrolysing bioactive peptides such as angiotensin II present in the circulation. A role for ACE2 in the metabolism of other biologically active peptides also needs to be considered. ACE2 also serendipitously appears to act as a receptor for the severe acute respiratory syndrome (SARS) coronavirus. Studies usingace2 -/- mice, and other emerging studiesin vivo andin vitro, have revealed that ACE2 has important functions in cardiac regulation and diabetes. Together with its role as a SARS receptor, ACE2 is therefore likely to be an important therapeutic target in a diverse range of disease states.
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Affiliation(s)
- Fiona J. Warner
- Baker Heart Research Institute, Peptide Biology, 3004 Melbourne, Victoria Australia
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, LS2 9JT Leeds, UK
| | - Jodie L. Guy
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, LS2 9JT Leeds, UK
| | - Dan W. Lambert
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, LS2 9JT Leeds, UK
| | - Nigel M. Hooper
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, LS2 9JT Leeds, UK
| | - Anthony J. Turner
- Proteolysis Research Group, School of Biochemistry and Microbiology, University of Leeds, LS2 9JT Leeds, UK
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Warner FJ, Miller RC, Burcher E. Structure-activity relationship of neurokinin A(4-10) at the human tachykinin NK(2) receptor: the effect of amino acid substitutions on receptor affinity and function. Biochem Pharmacol 2002; 63:2181-6. [PMID: 12110377 DOI: 10.1016/s0006-2952(02)01014-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A structure-activity study of the neurokinin A (NKA) fragment NKA(4-10) was performed to investigate the importance of amino acid residues for receptor efficacy, potency and affinity at the NK(2) receptor in human colon circular muscle. Fourteen analogs of NKA(4-10) were produced with substitutions at positions 4, 5, 7, 9 and/or 10 of NKA. Their potencies were determined by in vitro contractile responses and affinities by radioligand binding using [125I]NKA. Functional potency was enhanced 8-fold by single amino acid substitutions with Lys(5) and MeLeu(9) but not significantly altered by substitutions Glu(4), Arg(5), His(5) and Nle(10). The multiply-substituted analogs [MeLeu(9),Nle(10)]NKA(4-10), [Lys(5),MeLeu(9),Nle(10)]NKA(4-10) and [Lys(5),(Tyr(7)),MeLeu(9),Nle(10)]NKA(4-10) displayed 6-9-fold increase in potency. Although [Arg(5),Nle(10)]NKA(4-10) was similar in potency to NKA(4-10), it was the only analog to show significantly reduced efficacy. All analogs were able to compete fully for [125I]NKA binding. [Lys(5),MeLeu(9)]NKA(4-10), [MeLeu(9),Nle(10)]NKA(4-10), [Lys(5),Nle(10)]NKA(4-10) and analogs containing single substitutions with Glu(4), Arg(5), Lys(5) and MeLeu(9) displayed significantly higher affinity, whereas those with Nle(10) and [Glu(4),Nle(10)] substitutions showed significantly lower affinity than NKA(4-10). There was a positive correlation (r=0.63) between binding affinity and functional potency, which was markedly improved (r=0.95) by removal of three analogs: [Lys(5),MeLeu(9),Nle(10)]NKA(4-10), [Lys(5),Tyr(7),MeLeu(9),Nle(10)]NKA(4-10) and [Lys(5),Tyr(I(2))(7),MeLeu(9),Nle(10)]NKA(4-10). These exhibited similar binding affinities to that of NKA(4-10) but were more potent in functional studies, possibly indicating a different mechanism of receptor interaction. In conclusion, substitution of Ser(5) with Lys, and/or N-methylation of Leu(9), were the most effective changes to increase functional and binding potency of NKA(4-10) at the human colon NK(2) receptor.
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Affiliation(s)
- Fiona J Warner
- Department of Physiology and Pharmacology, University of New South Wales, Sydney, Australia
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Warner FJ, Shang F, Millard RJ, Burcher E. Enhancement of neurokinin A-induced smooth muscle contraction in human urinary bladder by mucosal removal and phosphoramidon: relationship to peptidase inhibition. Eur J Pharmacol 2002; 438:171-7. [PMID: 11909608 DOI: 10.1016/s0014-2999(02)01316-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neurokinin A (NKA) is potent in contracting the human detrusor muscle. Here, we have investigated whether these contractile responses are influenced by the presence of the mucosa, by the peptidase inhibitor phosphoramidon or by possible modulators, prostaglandins and nitric oxide. Contractile responses to neurokinin A were unaffected by indomethacin or N-omega-nitro-L-arginine, but were significantly reduced in strips containing mucosa. Phosphoramidon, an inhibitor of neutral endopeptidase 24.11 (neprilysin, CD10), was ineffective at 10 microM, but at 100 microM, significant increase in the maximum response was achieved by neurokinin A in detrusor strips with and without mucosa. In immunohistochemical studies, neutral endopeptidase immunoreactivity occurred in peripheral nerve trunks in the detrusor and in a fibrous meshwork in the subepithelial lamina propria. Our data indicate that neutral endopeptidase is present in bladder mucosa and detrusor, and support the concept that this metalloprotease and/or related enzymes are important in regulating the actions of tachykinins.
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Affiliation(s)
- Fiona J Warner
- Department of Physiology and Pharmacology, University of New South Wales, NSW 2052, Sydney, Australia
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Warner FJ, Mack P, Comis A, Miller RC, Burcher E. Structure-activity relationships of neurokinin A (4-10) at the human tachykinin NK(2) receptor: the role of natural residues and their chirality. Biochem Pharmacol 2001; 61:55-60. [PMID: 11137709 DOI: 10.1016/s0006-2952(00)00516-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A structure-activity study of neurokinin A (NKA) (4-10) was performed to investigate the importance of residue and chirality for affinity and efficacy at the NK(2) receptor in human colon circular muscle. Two series of NKA(4-10) analogues were produced with either L-alanine or the D-enantiomer substituted. Their activities were determined in vitro by means of radioligand binding and isolated smooth muscle pharmacology. NKA was more potent than NKA(4-10) at the human, unlike the rabbit, NK(2) receptor. The contractile response of NKA(4-10) was unaffected by N-terminal acetylation. L-Ala substitution of Asp(4), Val(7), Leu(9), and Met(10) caused an 8- to 80-fold decrease, and substitution of Phe(6) caused a 5000-fold decrease in binding affinity (P < 0.01). Positions Ser(5) and Gly(8) were not significantly affected. In functional studies, a similar pattern was observed. The replacement of residues with their respective D-enantiomer drastically reduced binding affinity and functional potency, particularly at positions 6 and 7 (P < 0.05). NKA(4-10) analogues L-Ala(6), L-Ala(8), D-Phe(6), D-Val(7), and D-Met(10) were partial agonists. An excellent correlation was observed between binding and functional data (r = 0.95). A retro-inverso analogue of NKA(4-10) was inactive. In conclusion, the side chains of Asp(4), Phe(6), Val(7), Leu(9), and Met(10) are structurally important features of NKA(4-10) for agonist activity, and changes in amino acid chirality are detrimental to binding affinity and functional activity. Overall, our data are broadly similar to those of previous studies in the rat. However, at the human NK(2) receptor, unlike the rat, [Ala(8)]NKA(4-10) was an antagonist.
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Affiliation(s)
- F J Warner
- School of Physiology and Pharmacology, University of New South Wales, Sydney, Australia
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Warner FJ, Liu L, Lubowski DZ, Burcher E. Circular muscle contraction, messenger signalling and localization of binding sites for neurokinin A in human sigmoid colon. Clin Exp Pharmacol Physiol 2000; 27:928-33. [PMID: 11071312 DOI: 10.1046/j.1440-1681.2000.03363.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. Neurokinin (NK)A is the endogenous ligand for the tachykinin NK2 receptor. In the present study, tachykinins and selective receptor agonists were tested as contractile agonists in human colon circular muscle and [125I]-NKA was used to localize binding sites in human colon. 2. In strips of circular muscle, removal of mucosa and submucosa significantly (P < 0.05) increased the potency and the maximum response achieved by NKA. 3. The rank order of potency of tachykinin and selective receptor agonists in contracting circular muscle strips was NKA > or = [Lys5,MeLeu9,Nle10]NKA(4-10) > or = neuropeptide (NP)gamma > or = [betaAla8]NKA(4-10) >> NKB > substance P (SP) >> senktide approximate to [Pro9]SP. 4. Specific binding sites for [125I]-NKA were densely localized over circular muscle and muscularis mucosae. Weak specific binding was seen on longitudinal muscle and taenia coli, whereas no binding sites were seen on mucosa, ganglia or blood vessels. 5. In circular muscle, the selective NK2 receptor agonist [LysS,MeLeu9,Nle10]NKA(4-10) produced weak increases (maximum 37%) in inositol monophosphate formation with a pD2 of 6.8+/-0.51 (n = 3). Carbachol (100 micromol/L) was also a weak stimulant (maximum 45%). These agonists were over 10-fold more efficacious in stimulation of inositol monophosphate in rat urinary bladder. 6. In conclusion, [125I]-NKA binding sites localized on human colon circular muscle were characterized as NK2 receptors. Functionally, the tachykinin NK2 receptor is mediating circular smooth muscle contraction. Although the human NK2 receptor is coupled to the phosphatidylinositol pathway, other second messenger mechanisms may also operate in this tissue.
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Affiliation(s)
- F J Warner
- School of Physiology and Pharmacology, University of New South Wales, Sydney, Australia
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Renzetti AR, Catalioto RM, Criscuoli M, Cucchi P, Ferrer C, Giolitti A, Guelfi M, Rotondaro L, Warner FJ, Maggi CA. Relevance of aromatic residues in transmembrane segments V to VII for binding of peptide and nonpeptide antagonists to the human tachykinin NK(2) receptor. J Pharmacol Exp Ther 1999; 290:487-95. [PMID: 10411554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
We used membranes from Chinese hamster ovary cells stably transfected with the human tachykinin NK(2) receptor, either wild-type or mutated, at four aromatic residues (His(198), Tyr(266), Phe(270), Tyr(289)) located in transmembrane segments V to VII, to assess the role of these residues in the binding of natural tachykinins and peptide and nonpeptide antagonists. Three radioligands, the agonist [(125)I]neurokinin A (NKA), the peptide antagonist [(3)H]MEN 11420, and the nonpeptide antagonist [(3)H]SR 48968 bound to the wild-type receptor with high affinity (K(d) = 2.4 nM, 0.3 nM, and 4.0 nM, respectively). Four of the six mutant receptors tested retained high affinity for at least one of the radioligands. H(198)A mutation abrogated the binding of NKA but not that of MEN 11420 or SR 48968 (K(d) = 4.8 and 11.5 nM, respectively); Y(266)F mutation abrogated the binding of MEN 11420 but not that of NKA or SR 48968 (K(d) = 2.8 nM and 1.2 nM, respectively); F(270)A mutation abrogated the binding of both NKA and MEN 11420 but not that of SR 48968 (K(d) = 1.6 nM); Y(289)F mutation abrogated the binding of SR 48968 but not that of NKA and MEN 11420 (K(d) = 2.0 and 2.9 nM, respectively). Y(266)A and Y(289)A mutations abrogated the binding of all radioligands. Among the unlabeled antagonists, the affinity of the nonpeptide GR 159897, at variance with SR 48968, resulted heavily compromised by H(198)A and Y(266)F mutations; the peptide antagonists R396 and MEN 10376 essentially followed the binding profile of NKA, but R396 showed markedly increased affinity for the Y(289)F mutant receptor. Taken together, these results indicate that different, partially overlapping sets of sites may be involved in the binding of agonists and diverse antagonists to the human tachykinin NK(2) receptor.
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MESH Headings
- Animals
- Benzamides/chemistry
- Benzamides/metabolism
- Benzamides/pharmacology
- Binding, Competitive
- CHO Cells
- Cricetinae
- DNA, Complementary/drug effects
- DNA, Complementary/genetics
- Humans
- Indoles/chemistry
- Indoles/metabolism
- Indoles/pharmacology
- Mutagenesis, Site-Directed
- Mutation
- Neurokinin A/chemistry
- Neurokinin A/metabolism
- Neurokinin A/pharmacology
- Peptides/chemistry
- Peptides/metabolism
- Peptides, Cyclic/chemistry
- Peptides, Cyclic/metabolism
- Peptides, Cyclic/pharmacology
- Piperidines/chemistry
- Piperidines/metabolism
- Piperidines/pharmacology
- Protein Conformation
- Receptors, Neurokinin-2/antagonists & inhibitors
- Receptors, Neurokinin-2/chemistry
- Receptors, Neurokinin-2/genetics
- Receptors, Neurokinin-2/metabolism
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Affiliation(s)
- A R Renzetti
- Department of Pharmacology, Menarini Ricerche S.p.A., Firenze, Italy
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Liu L, Warner FJ, Conlon JM, Burcher E. Pharmacological and biochemical investigation of receptors for the toad gut tachykinin peptide, bufokinin, in its species of origin. Naunyn Schmiedebergs Arch Pharmacol 1999; 360:187-95. [PMID: 10494889 DOI: 10.1007/s002109900069] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This is the first report of the development of a new radioligand [125I]Bolton-Hunter bufokinin ([125I]BH-bufokinin) and its use in the characterisation of tachykinin receptors in the small intestine of the cane toad, Bufo matrinus. The binding of [125I]BH-bufokinin to toad intestinal membranes was rapid, saturable, of high affinity and to a single population of binding sites with KD 0.57 nM and Bmax 3.1 fmol mg wet weight tissue(-1). The rank order of affinity of tachykinins to compete for [125I]-BH bufokinin binding revealed similarities with that of the mammalian NK1 receptor, being bufokinin (IC50, 1.7 nM)>physalaemin (6.7 nM)>substance P (SP, 10.7 nM)> or =neuropeptide gamma (NPgamma, 12.4 nM)> or =kassinin (17.8 nM)>scyliorhinin I (35.3 nM)> or =eledoisin (40.6 nM)> or =carassin (43.2 nM)> or =neurokinin A (NKA, 57.8 nM)> or =neurokinin B (NKB, 77.5 nM)>scyliorhinin II (338 nM). The mammalian NK3-selective agonist senktide was a very weak competitor. The radioligand [125I]neurokinin A showed no specific binding to toad intestinal membranes. In the toad isolated small intestine, the maximum contractile response to bufokinin was over 150% greater than that to acetylcholine in longitudinal muscle, whereas responses to bufokinin and acetylcholine were similar in circular muscle. Bufokinin was the most potent agonist (EC501 0.34 nM) and produced a long-lasting contraction. Other tachykinins such as physalaemin, SP and kassinin were also potent contractile agents. The potency values of mammalian and amphibian tachykinins derived from functional studies (pD2) correlated significantly with those from binding assays (pKi). The data for fish and molluscan tachykinins, however, showed poor correlation. Contractions to bufokinin and SP were unaffected by atropine, indomethacin and tetrodotoxin. The highly selective NK1 receptor antagonists CP 99994, GR 82334 and RP 67580 were ineffective in both binding and functional studies. Bufokinin increased inositol monophosphate formation in a concentration-dependent manner with an EC50 value of 10.7 nM, suggesting that the tachykinin receptor may be coupled to phosphoinositol hydrolysis. In summary, this study provides evidence for a high-affinity, bufokinin-preferring, NK1-like tachykinin receptor in the toad small intestine. This is probably not the receptor which mediates contraction to carassin, scyliorhinin II and eledoisin. The study also provides evidence that bufokinin and its receptor play an important physiological role in regulating intestinal motility.
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Affiliation(s)
- L Liu
- School of Physiology and Pharmacology, University of New South Wales, Sydney, Australia.
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Abstract
Neurokinin A (NKA) is a potent contractile agonist of human colon circular muscle. These responses are mediated predominantly through tachykinin NK2 receptors. In the present study, the NK2 receptor radioligand [125I]-NKA has been used to characterize binding sites in this tissue, using tachykinin agonists and antagonists. 125INKA labelled a single, high affinity binding site. Specific binding (95% of total binding) of [125I]-NKA was saturable (K(D) 0.47+/-0.05 nM), of high capacity (Bmax 2.1+/-0.1 fmol mg(-1) wet weight tissue) and reversible (kinetically derived K(D) 0.36+/-0.07 nM). The rank order of agonists competing for the [125I]-NKA binding site was neuropeptide gamma (NPgamma) > or = NKA > or = [Lys5, MeLeu9,Nle10]NKA (4-10) (NK2 agonist) >> substance P (SP) > neurokinin B (NKB) > or = [Pro9]SP (NK1 agonist) >> senktide (NK3 agonist), indicating binding to an NK2 site. The nonpeptide selective NK2 antagonist SR48968 showed higher affinity for the [125I]-NKA site than selective peptide NK2 antagonists. The rank order of potency for NK2 antagonists was SR48968 > or = MEN11420 > GR94800 > or = MEN10627 > MEN10376 > or = R396. The NK1 antagonist SR140333 was a weak competitor. The competition curve for SP could be resolved into two sites. When experiments were repeated in the presence of SR140333 (0.1 microM), the curve for SP became monophasic and showed a significant shift to the right, whereas curves to NKA and NKB were unaffected. In conclusion, binding of the radioligand [125I]-NKA to membranes from circular muscle is predominantly to the NK2 receptor. There may be a small component of binding to the NK1 receptor. The NK2 receptor mediates circular muscle contraction, whereas the role of the NK1 receptor in circular muscle is unclear.
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Affiliation(s)
- Fiona J Warner
- School of Physiology and Pharmacology, University of New South Wales, NSW 2052, Australia
| | - Alfio Comis
- School of Science, University of Western Sydney, Hawkesbury, Richmond, NSW 2753 Australia
| | | | - Elizabeth Burcher
- School of Physiology and Pharmacology, University of New South Wales, NSW 2052, Australia
- Author for correspondence:
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Faaland CA, Race JE, Ricken G, Warner FJ, Williams WJ, Holtzman EJ. Molecular characterization of two novel transporters from human and mouse kidney and from LLC-PK1 cells reveals a novel conserved family that is homologous to bacterial and Aspergillus nucleobase transporters. Biochim Biophys Acta 1998; 1442:353-60. [PMID: 9804989 DOI: 10.1016/s0167-4781(98)00151-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nucleobase transport is important for the metabolism of nucleic acids and antiviral and antineoplastic drugs. This transport has been functionally described in several mammalian cells but has not been well characterized molecularly. We report the cloning of two novel transporters. YSPL2 encodes a 650-residue protein and has an ubiquitous 8 kb transcript. The human and pig homologs are 95% similar. YSPL3 encodes a 598-residue protein with a 3 kb transcript that is expressed only in kidney and liver. Human YSPL2 and YSPL3 are 60% similar at the amino acid level and both show 31% similarity to the first nucleobase permease gene described in vertebrates, YSPL1. These proteins appear to be members of a new family of possible nucleobase transporters with significant sequence similarities with bacterial and Aspergillus nucleobase transporters. Further functional studies will be needed to unveil the role of these transporters in nucleic acid metabolism in normal and in disease states.
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Affiliation(s)
- C A Faaland
- Renal Division, Department of Medicine, SUNY-Health Science Center, Syracuse, NY, USA
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Burcher E, Warner FJ. Tachykinin receptors in the small intestine of the cane toad (Bufo marinus): a radioligand binding and functional study. Naunyn Schmiedebergs Arch Pharmacol 1998; 357:692-700. [PMID: 9686947 DOI: 10.1007/pl00005226] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In this study, we have used radioligand binding and functional techniques to investigate tachykinin receptors in the small intestine of the cane toad Bufo marinus. The radioligand [125I]Bolton-Hunter [Sar9,Met(O2)11]substance P (selective at mammalian NK-1 receptors) showed no specific binding. Specific binding of [125I]Bolton-Hunter substance P ([125I]BHSP) was saturable, of high affinity (Kd 0.3 nM) and was inhibited by SP (IC50 0.64 nM) > ranakinin approximately neurokinin A (NKA) > or = SP(5-11) > or = neuropeptide gamma > or = scyliorhinin II > scyliorhinin I > or = [Sar9]-SP > or = neurokinin B approximately physalaemin approximately carassin >> SP(7-11) approximately eledoisin > or = SP(4-11) approximately SP(6-11). Binding was also inhibited by Gpp[NH]p > or = GTPgammaS > App[NH]p, indicating a G-protein coupled receptor. The order of potency of tachykinins and analogues in contracting the isolated lower small intestine was carassin (EC50 1.4 nM) > eledoisin approximately SP > or = physalaemin > or = ranakinin > SP(6-11) > scyliorhinin II > or = neuropeptide gamma > neurokinin B approximately NKA approximately scyliorhinin I > or = SP(4-11) > or = SP(5-11) > [Sar9]SP > SP(7-11). In both studies, the selective mammalian NK-1, NK-2 and NK-3 receptor agonists [Sar9,Met(O2)11]SP, [Lys5,Me-Leu9,Nle10]NKA(4-10) and senktide were weak or ineffective. There was a strong positive correlation between the pD2 and pIC50 values for mammalian tachykinins and analogues (r = 0.907), but not for the non-mammalian tachykinins, which were all full agonists but variable binding competitors. [Sar9,Met(O2)11]-SP(pD2 5.7) was approximately 25-fold less potent as an agonist than [Sar9]SP, which was itself 25-fold weaker than SP. Responses to SP were significantly reduced (n = 8, P<0.001) by the antagonist [D-Arg1,D-Trp7,9,Leu11]-SP (spantide; 1 microM). Highly selective NK-1 receptor antagonists including CP 99994 and GR 82334 (both 1 microM) were ineffective in both functional and binding studies. Tetrodotoxin (1 microM) did not inhibit contractile responses to SP, NKA and senktide. In summary, this study has shown the presence of one or more tachykinin receptor in the toad intestine. The binding site recognised by [125I]BHSP prefers SP and ranakinin. This toad "NK-1-like receptor" differs from the mammalian NK-1 receptor in having a low affinity for all mammalian NK-1 selective ligands, including antagonists. For some non-mammalian peptides, their high potency as contractile agonists relative to their poor binding affinity suggests the existence of other tachykinin receptors in the toad small intestine.
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Affiliation(s)
- E Burcher
- School of Physiology and Pharmacology, University of New South Wales, Kensington, Australia
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Conlon JM, Warner FJ, Burcher E. Bufokinin: a substance P-related peptide from the gut of the toad, Bufo marinus with high binding affinity but low selectivity for mammalian tachykinin receptors. J Pept Res 1998; 51:210-5. [PMID: 9531424 DOI: 10.1111/j.1399-3011.1998.tb01218.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A tachykinin peptide, termed bufokinin, was isolated in pure form from an extract of the intestine of the toad, Bufo marinus, and its primary structure was established as: Lys-Pro-Arg-Pro-Asp-Gln-Phe-Tyr-Gly-Leu-Met.NH2. This sequence was confirmed by chemical synthesis and shows four amino acid substitutions (Arg1 --> Lys,Lys3 --> Arg,Gln5 --> Asp and Phe8 --> Tyr) compared with substance P. Binding parameters for synthetic bufokinin and mammalian tachykinins were compared using receptor-selective radioligands and crude membranes from rat tissues enriched in the NK-1 (submandibular gland) , NK-2 (stomach fundus) and NK-3 (brain) receptors. In terms of inhibiting the binding of the selective radioligands, bufokinin (Kd = 0.3 nM) was 1.8-fold more potent than substance P at the rat NK-1 site, but it was only 2-fold less potent (Kd = 2.8 nM) than neurokinin A at the NK-2 site and only 2-fold less potent (Kd = 48 nM) than neurokinin B at the NK-3 site. Thus, bufokinin shows relatively high affinity but lack of selectivity for all three tachykinin binding sites in rat tissues.
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Affiliation(s)
- J M Conlon
- Regulatory Peptide Center, Department of Biomedical Sciences, Creighton University Medical School, Omaha, Nebraska 68178-0405, USA.
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Abstract
Neurotensin (NT) was isolated from an extract of the intestine of the cane toad, Bufo marinus and its primary structure established as: pGlu-Ala-Ile-Val-Ser-Lys-Ala-Arg-Arg-Pro-Tyr-Ile-Leu. This amino acid sequence shows five substitutions (Leu2 --> Ala, Tyr3 --> Ile, Glu4 --> Val, Asn5 --> Ser, and Pro7 --> Ala) compared with bovine NT. Synthetic Bufo NT (pD2 = 8.05 +/- 0.28) was equipotent and equally effective as bovine NT (pD2 = 8.24 +/- 0.38) in producing spasmogenic contraction of isolated segments of toad small intestine. However, the maximum response produced by Bufo NT was only 35 +/- 2% of that produced by substance P. The potencies, but not the maximum responses, to Bufo and bovine NT were significantly (p < 0.05) attenuated by pre-treatment with atropine but neither parameter was significantly diminished by tetrodotoxin and indomethacin. The data suggest that the action of NT involves interaction with receptors on toad intestinal smooth muscle that recognize the C-terminal region of NT (residues 8-13) that has been fully conserved during evolution of tetrapods. Contractile activity is mediated, at least in part, by release of acetylcholine.
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Affiliation(s)
- F J Warner
- School of Physiology and Pharmacology, University of New South Wales, Sydney, Australia
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Warner FJ. Freezing with chicken juice. Pediatrics 1994; 93:696. [PMID: 8134238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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Warner FJ. The development of the forebrain in Trichosurus vulpecula. Okajimas Folia Anat Jpn 1980; 57:265-320. [PMID: 7254756 DOI: 10.2535/ofaj1936.57.5_265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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