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Parthasarathy R, Wakefield D, Santiago FS, Kaakoush NO, Tedla N. Horizontal gene transfer and endogenous retroviruses as mechanisms for molecular mimicry. Lancet Microbe 2024; 5:e4-e5. [PMID: 37883987 DOI: 10.1016/s2666-5247(23)00316-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 09/26/2023] [Accepted: 09/26/2023] [Indexed: 10/28/2023]
Affiliation(s)
- Rohit Parthasarathy
- School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia
| | - Denis Wakefield
- School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia
| | - Fernando S Santiago
- School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia
| | - Nadeem O Kaakoush
- School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Nicodemus Tedla
- School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia.
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Abstract
Background Vascular endothelial cell proliferation, migration, and network formation are key proangiogenic processes involving the prototypic immediate early gene product, Egr‐1 (early growth response‐1). Egr‐1 undergoes phosphorylation at a conserved Ser26 but its function is completely unknown in endothelial cells or any other cell type. Methods and Results A CRISPR/Cas9 strategy was used to introduce a homozygous Ser26>Ala mutation into endogenous Egr‐1 in human microvascular endothelial cells. In the course of generating mutant cells, we produced cells with homozygous deletion in Egr‐1 caused by frameshift and premature termination. We found that Ser26 mutation in Egr‐1, or Egr‐1 deletion, perturbed endothelial cell proliferation in models of cell counting or real‐time growth using the xCELLigence System. We found that Ser26 mutation or Egr‐1 deletion ameliorated endothelial cell migration toward VEGF‐A165 (vascular endothelial growth factor‐A) in a dual‐chamber model. On solubilized basement membrane preparations, Ser26 mutation or Egr‐1 deletion prevented endothelial network (or tubule) formation, an in vitro model of angiogenesis. Flow cytometry further revealed that Ser26 mutation or Egr‐1 deletion elevated early and late apoptosis. Finally, we demonstrated that Ser26 mutation or Egr‐1 deletion increased VE‐cadherin (vascular endothelial cadherin) expression, a regulator of endothelial adhesion and signaling, permeability, and angiogenesis. Conclusions These findings not only indicate that Egr‐1 is essential for endothelial cell proliferation, migration, and network formation, but also show that point mutation in Ser26 is sufficient to impair each of these processes and trigger apoptosis as effectively as the absence of Egr‐1. This highlights the importance of Ser26 in Egr‐1 for a range of proangiogenic processes.
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Affiliation(s)
- Fernando S Santiago
- Vascular Biology and Translational Research School of Medical Sciences UNSW Medicine and HealthUniversity of New South Wales Sydney NSW Australia
| | - Yue Li
- Vascular Biology and Translational Research School of Medical Sciences UNSW Medicine and HealthUniversity of New South Wales Sydney NSW Australia
| | - Levon M Khachigian
- Vascular Biology and Translational Research School of Medical Sciences UNSW Medicine and HealthUniversity of New South Wales Sydney NSW Australia
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Santiago FS, Li Y, Zhong L, Raftery MJ, Lins L, Khachigian LM. Truncated YY1 interacts with BASP1 through a 339KLK341 motif in YY1 and suppresses vascular smooth muscle cell growth and intimal hyperplasia after vascular injury. Cardiovasc Res 2021; 117:2395-2406. [PMID: 33508088 DOI: 10.1093/cvr/cvab021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 07/07/2020] [Revised: 10/27/2020] [Accepted: 01/19/2021] [Indexed: 11/12/2022] Open
Abstract
AIMS In-stent restenosis and late stent thrombosis are complications associated with the use of metallic and drug-coated stents. Strategies that inhibit vascular smooth muscle cell (SMC) proliferation without affecting endothelial cell (EC) growth would be helpful in reducing complications arising from percutaneous interventions. Our group previously showed that the forced expression of the injury-inducible zinc finger (ZNF) transcription factor, yin yang-1 (YY1) comprising 414 residues inhibits neointima formation in carotid arteries of rabbits and rats. YY1 inhibits SMC proliferation without affecting EC growth. Identifying a shorter version of YY1 retaining cell-selective inhibition would make it more amenable for potential use as a gene therapeutic agent. METHODS AND RESULTS We dissected YY1 into a range of shorter fragments (YY1A-D, YY1Δ) and found that the first two ZNFs in YY1 (construct YY1B, spanning 52 residues) repressed SMC proliferation. Receptor Binding Domain analysis predicts a three residue (339KLK341) interaction domain. Mutation of 339KLK341 to 339AAA341 in YY1B (called YY1Bm) abrogated YY1B's ability to inhibit SMC but not EC proliferation and migration. Incubation of recombinant GST-YY1B and GST-YY1Bm with SMC lysates followed by precipitation with glutathione-agarose beads and mass spectrometric analysis identified a novel interaction between YY1B and BASP1. Overexpression of BASP1, like YY1, inhibited SMC but not EC proliferation and migration. BASP1 siRNA partially rescued SMC from growth inhibition by YY1B. In the rat carotid balloon injury model, adenoviral overexpression of YY1B, like full-length YY1, reduced neointima formation, whereas YY1Bm had no such effect. CD31 immunostaining suggested YY1B could increase re-endothelialization in a 339KLK341-dependent manner. CONCLUSIONS These studies identify a truncated form of YY1 (YY1B) that can interact with BASP1 and inhibits SMC proliferation, migration and intimal hyperplasia after balloon injury of rat carotid arteries as effectively as full length YY1. We demonstrate the therapeutic potential of YY1B in vascular proliferative disease.
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Affiliation(s)
- Fernando S Santiago
- Vascular Biology and Translational Research Laboratory, School of Medical Sciences, UNSW Medicine, University of New South Wales, Sydney NSW 2052, Australia
| | - Yue Li
- Vascular Biology and Translational Research Laboratory, School of Medical Sciences, UNSW Medicine, University of New South Wales, Sydney NSW 2052, Australia
| | - Ling Zhong
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney NSW 2052, Australia
| | - Mark J Raftery
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney NSW 2052, Australia
| | - Laurence Lins
- Molecular Biophysics at Interface Lab, University of Liège-Gembloux Agro Bio Tech, Passage des Déportés, 2-5030 Gembloux-Belgium
| | - Levon M Khachigian
- Vascular Biology and Translational Research Laboratory, School of Medical Sciences, UNSW Medicine, University of New South Wales, Sydney NSW 2052, Australia
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4
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Li Y, Alhendi AMN, Yeh MC, Elahy M, Santiago FS, Deshpande NP, Wu B, Chan E, Inam S, Prado-Lourenco L, Marchand J, Joyce RD, Wilkinson-White LE, Raftery MJ, Zhu M, Adamson SJ, Barnat F, Viaud-Quentric K, Sockler J, Mackay JP, Chang A, Mitchell P, Marcuccio SM, Khachigian LM. Thermostable small-molecule inhibitor of angiogenesis and vascular permeability that suppresses a pERK-FosB/ΔFosB-VCAM-1 axis. Sci Adv 2020; 6:eaaz7815. [PMID: 32923607 PMCID: PMC7450479 DOI: 10.1126/sciadv.aaz7815] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
Vascular permeability and angiogenesis underpin neovascular age-related macular degeneration and diabetic retinopathy. While anti-VEGF therapies are widely used clinically, many patients do not respond optimally, or at all, and small-molecule therapies are lacking. Here, we identified a dibenzoxazepinone BT2 that inhibits endothelial cell proliferation, migration, wound repair in vitro, network formation, and angiogenesis in mice bearing Matrigel plugs. BT2 interacts with MEK1 and inhibits ERK phosphorylation and the expression of FosB/ΔFosB, VCAM-1, and many genes involved in proliferation, migration, angiogenesis, and inflammation. BT2 reduced retinal vascular leakage following rat choroidal laser trauma and rabbit intravitreal VEGF-A165 administration. BT2 suppressed retinal CD31, pERK, VCAM-1, and VEGF-A165 expression. BT2 reduced retinal leakage in rats at least as effectively as aflibercept, a first-line therapy for nAMD/DR. BT2 withstands boiling or autoclaving and several months' storage at 22°C. BT2 is a new small-molecule inhibitor of vascular permeability and angiogenesis.
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Affiliation(s)
- Yue Li
- Vascular Biology and Translational Research, School of Medical Sciences and UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Ahmad M. N. Alhendi
- Vascular Biology and Translational Research, School of Medical Sciences and UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Mei-Chun Yeh
- Vascular Biology and Translational Research, School of Medical Sciences and UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Mina Elahy
- Vascular Biology and Translational Research, School of Medical Sciences and UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Fernando S. Santiago
- Vascular Biology and Translational Research, School of Medical Sciences and UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Nandan P. Deshpande
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Ben Wu
- Vascular Biology and Translational Research, School of Medical Sciences and UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Enoch Chan
- Vascular Biology and Translational Research, School of Medical Sciences and UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Shafqat Inam
- Vascular Biology and Translational Research, School of Medical Sciences and UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Leonel Prado-Lourenco
- Vascular Biology and Translational Research, School of Medical Sciences and UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Jessica Marchand
- Advanced Molecular Technologies Pty Ltd, Scoresby, VIC 3179, Australia
| | - Rohan D. Joyce
- Advanced Molecular Technologies Pty Ltd, Scoresby, VIC 3179, Australia
| | | | - Mark J. Raftery
- Bioanalytical Mass Spectrometry Facility, University of New South Wales, Sydney, NSW 2052, Australia
| | - Meidong Zhu
- New South Wales Tissue Bank, New South Wales Organ and Tissue Donation Service, South Eastern Sydney Local Health District, Kogarah, NSW 2217, Australia
- Save Sight Institute, Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, NSW 2006, Australia
- GreenLight Clinical Pty. Ltd., Woolloomooloo, NSW 2011, Australia
| | | | | | | | - Jim Sockler
- Statistical Operations and Programming, Datapharm Australia Pty. Ltd., Drummoyne, NSW 2047, Australia
| | - Joel P. Mackay
- School of Life and Environmental Sciences, University of Sydney, NSW 2006, Australia
| | - Andrew Chang
- Save Sight Institute, Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, NSW 2006, Australia
- GreenLight Clinical Pty. Ltd., Woolloomooloo, NSW 2011, Australia
- Sydney Eye Hospital, Sydney NSW 2000 and University of Sydney, NSW 2006, Australia
| | - Paul Mitchell
- Centre for Vision Research, Department of Ophthalmology, Westmead Institute for Medical Research, Westmead Hospital, University of Sydney, Westmead, NSW 2145, Australia
| | - Sebastian M. Marcuccio
- Advanced Molecular Technologies Pty Ltd, Scoresby, VIC 3179, Australia
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Levon M. Khachigian
- Vascular Biology and Translational Research, School of Medical Sciences and UNSW Medicine, University of New South Wales, Sydney, NSW 2052, Australia
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Santiago FS, Sanchez-Guerrero E, Zhang G, Zhong L, Raftery MJ, Khachigian LM. Extracellular signal-regulated kinase-1 phosphorylates early growth response-1 at serine 26. Biochem Biophys Res Commun 2019; 510:345-351. [PMID: 30711252 DOI: 10.1016/j.bbrc.2019.01.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 01/04/2019] [Indexed: 11/30/2022]
Abstract
Egr-1, an immediate-early gene product and master regulator was originally described as a phosphoprotein following its discovery in the 1980s. However specific residue(s) phosphorylated in Egr-1 remain elusive. Here we phosphorylated recombinant Egr-1 in vitro with ERK1 prior to mass spectrometry, which identified phosphorylation of Ser12 and Ser26 with the latter ∼12 times more abundant than Ser12. Phosphorylation of wild-type recombinant Egr-1 (as compared with Ser26>Ala26 mutant Egr-1) revealed that Ser26 accounts for the majority of phosphorylation of Egr-1 by ERK1. N-FGSFPH(pS)PTMDNYC-C was used as an antigen to generate mouse monoclonal antibodies (pS26 MAb). pS26 MAb recognised ERK1-phosphorylated Egr-1 but not Egr-1 bearing a point mutation at Ser26. pS26 MAb recognised inducible ∼75 kDa and 100 kDa species in nuclear extracts of cells exposed to FGF-2. Peptide blocking revealed both inducible species were phosphosite-specific. Immunoprecipitation of nuclear extracts of cells exposed to FGF-2 with pS26 MAb followed by SDS-PAGE and mass spectrometry identified Egr-1 sequences corresponding to the ∼75 kDa species but not ∼100 kDa species. This study identifies a specific amino acid phosphorylated in endogenous Egr-1.
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Affiliation(s)
- Fernando S Santiago
- Vascular Biology and Translational Research Laboratory, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | | | - Guishui Zhang
- UNSW Medicine, University of New South Wales, Sydney, Australia
| | - Ling Zhong
- Bioanalytical Mass Spectrometry Facility, University of New South Wales, Sydney, Australia
| | - Mark J Raftery
- Bioanalytical Mass Spectrometry Facility, University of New South Wales, Sydney, Australia
| | - Levon M Khachigian
- Vascular Biology and Translational Research Laboratory, School of Medical Sciences, University of New South Wales, Sydney, Australia; UNSW Medicine, University of New South Wales, Sydney, Australia.
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Buckler J, Banwell MG, Kordbacheh F, Parish CR, Santiago FS, Khachigian LM. Developing Neolignans as Proangiogenic Agents: Stereoselective Total Syntheses and Preliminary Biological Evaluations of the Four Guaiacylglycerol 8- O-4'-Coniferyl Ethers. ACS Omega 2017; 2:7375-7388. [PMID: 29242850 PMCID: PMC5724931 DOI: 10.1021/acsomega.7b01459] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 10/09/2017] [Indexed: 06/07/2023]
Abstract
Stereoselective total syntheses of the four stereoisomeric forms of guaiacylglycerol 8-O-4'-coniferyl ether, viz., compounds 1, ent-1, 2, and ent-2, have been established. The key step involves an Evans/Seebach auxiliary-controlled and syn-selective aldol process followed, in the reaction sequences leading to the anti-compounds, by a Mitsunobu reaction involving a benzylic alcohol residue. The proangiogenic properties of the synthetic materials were evaluated in a human microvascular endothelial cell tubule formation assay, thus revealing that they are all active, with the 8S-configured compounds 1 and 2 being the most potent.
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Affiliation(s)
- Joshua
N. Buckler
- Research
School of Chemistry, Institute of Advanced Studies and The John Curtin
School of Medical Research, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601, Australia
| | - Martin G. Banwell
- Research
School of Chemistry, Institute of Advanced Studies and The John Curtin
School of Medical Research, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601, Australia
| | - Farzaneh Kordbacheh
- Research
School of Chemistry, Institute of Advanced Studies and The John Curtin
School of Medical Research, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601, Australia
| | - Christopher R. Parish
- Research
School of Chemistry, Institute of Advanced Studies and The John Curtin
School of Medical Research, Institute of Advanced Studies, The Australian National University, Canberra, ACT 2601, Australia
| | - Fernando S. Santiago
- School
of Medical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Levon M. Khachigian
- School
of Medical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
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Ishii H, Hulett MD, Li JM, Santiago FS, Parish CR, Khachigian LM. Yin Yang-1 inhibits tumor cell growth and inhibits p21WAF1/Cip1 complex formation with cdk4 and cyclin D1. Int J Oncol 2012; 40:1575-80. [PMID: 22322893 DOI: 10.3892/ijo.2012.1362] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 01/09/2012] [Indexed: 01/17/2023] Open
Abstract
The GLI-Krüppel zinc finger factor yin yang-1 (YY1) is a complex protein that regulates a variety of processes including transcription, proliferation, development and differentiation. YY1 inhibits cell growth in a cell type-specific manner. The role played by YY1 in its control of tumor cell growth is unclear and controversial. We show here that YY1 can suppress the growth of different tumor cell types in vitro, including human breast carcinoma cells and glioblastoma cells. YY1 also blocked the growth of 13762 MAT mammary adenocarcinoma isografts in rats. YY1 inhibited 13762 MAT tumor growth by approximately 80% compared with the GFP alone group 21 days after injection. YY1 inhibited proliferating cell nuclear antigen (PCNA) expression and pRbSer249/Thr252 phosphorylation without influencing tumor microvascular density. Moreover, YY1 inhibited p21WAF1/Cip1 complex formation with cdk4 and cyclin D1. These findings demonstrate that YY1 can negatively regulate the growth of multiple malignant cell types.
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Affiliation(s)
- Hideto Ishii
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
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8
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Beck K, Wu BJ, Ni J, Santiago FS, Malabanan KP, Li C, Wang Y, Khachigian LM, Stocker R. Interplay between heme oxygenase-1 and the multifunctional transcription factor yin yang 1 in the inhibition of intimal hyperplasia. Circ Res 2010; 107:1490-7. [PMID: 21030713 DOI: 10.1161/circresaha.110.231985] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [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] [Indexed: 12/12/2022]
Abstract
RATIONALE induction of heme oxygenase (HO)-1 protects against experimental atherosclerotic diseases, and certain pharmacological HO-1 inducers, like probucol, inhibit the proliferation of vascular smooth muscle cells and, at the same time, promote the growth of endothelial cells in vivo and in vitro. OBJECTIVE because such cell-specific effects are reminiscent of the action of the transcription factor Yin Yang (YY)1, we tested the hypothesis that there is a functional relationship between HO-1 and YY1. METHODS AND RESULTS we report that probucol increases the number of YY1(+) cells in rat carotid artery following balloon injury at a time coinciding with increased HO-1 expression. The drug also induces the expression of YY1 mRNA and protein in rat aortic smooth muscle cells (RASMCs) in vitro, as do other known HO-1 inducers (tert-butylhydroquinone and hemin) and overexpression of HO-1 using a human HMOX1 cDNA plasmid. Conversely, overexpression of YY1 induces expression of HO-1 in RASMCs. Induction of YY1 expression is dependent on HO-1 enzyme activity and its reaction product CO, because pharmacological inhibition of heme oxygenase activity or CO scavenging block, whereas exposure of RASMCs to a CO-releasing molecule increases, YY1 expression. Furthermore, RNA interference knockdown of YY1 prevents probucol or adeno-HO-1 from inhibiting RASMC proliferation in vitro and neointimal formation in vivo. CONCLUSIONS our findings show, for the first time, that HO-1 functionally interplays with the multifunctional transcription factor YY1 and that this interplay explains some of the protective activities of HO-1.
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Affiliation(s)
- Konstanze Beck
- Centre for Vascular Research, School of Medical Sciences and Bosch Institute, Medical Foundation Building (K25), University of Sydney, 92-94 Parramatta Rd, Camperdown, NSW 2006, Australia
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Cheng Q, McKeown SJ, Santos L, Santiago FS, Khachigian LM, Morand EF, Hickey MJ. Macrophage migration inhibitory factor increases leukocyte-endothelial interactions in human endothelial cells via promotion of expression of adhesion molecules. J Immunol 2010; 185:1238-47. [PMID: 20554956 DOI: 10.4049/jimmunol.0904104] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Macrophage migration inhibitory factor (MIF) has been shown to promote leukocyte-endothelial cell interactions, although whether this occurs via an effect on endothelial cell function remains unclear. Therefore, the aims of this study were to examine the ability of MIF expressed by endothelial cells to promote leukocyte adhesion and to investigate the effect of exogenous MIF on leukocyte-endothelial interactions. Using small interfering RNA to inhibit HUVEC MIF production, we found that MIF deficiency reduced the ability of TNF-stimulated HUVECs to support leukocyte rolling and adhesion under flow conditions. These reductions were associated with decreased expression of E-selectin, ICAM-1, VCAM-1, IL-8, and MCP-1. Inhibition of p38 MAPK had a similar effect on adhesion molecule expression, and p38 MAPK activation was reduced in MIF-deficient HUVECs, suggesting that MIF mediated these effects via promotion of p38 MAPK activation. In experiments examining the effect of exogenous MIF, application of MIF to resting HUVECs failed to induce leukocyte rolling and adhesion, whereas addition of MIF to TNF-treated HUVECs increased these interactions. This increase was independent of alterations in TNF-induced expression of E-selectin, VCAM-1, and ICAM-1. However, combined treatment with MIF and TNF induced de novo expression of P-selectin, which contributed to leukocyte rolling. In summary, these experiments reveal that endothelial cell-expressed MIF and exogenous MIF promote endothelial adhesive function via different pathways. Endogenous MIF promotes leukocyte recruitment via effects on endothelial expression of several adhesion molecules and chemokines, whereas exogenous MIF facilitates leukocyte recruitment induced by TNF by promoting endothelial P-selectin expression.
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Affiliation(s)
- Qiang Cheng
- Department of Medicine, Monash Medical Centre, Centre for Inflammatory Diseases, Monash University, Clayton, Victoria, Australia
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Wang B, Chen J, Santiago FS, Janes M, Kavurma MM, Chong BH, Pimanda JE, Khachigian LM. Phosphorylation and acetylation of histone H3 and autoregulation by early growth response 1 mediate interleukin 1beta induction of early growth response 1 transcription. Arterioscler Thromb Vasc Biol 2009; 30:536-45. [PMID: 20018936 DOI: 10.1161/atvbaha.109.193821] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE The transcription factor early growth response (EGR)-1 has been implicated as a key vascular phenotypic switch through its control of inducible transcription. EGR-1 autoregulation, and histone modification in the EGR-1 promoter, represent key mechanisms in EGR-1 control, but have not been explored. METHODS AND RESULTS We demonstrate that EGR-1 regulates its own transcription and that this involves histone H3 phosphorylation and acetylation. EGR-1 transactivates its promoter in smooth muscle cells exposed to interleukin (IL) 1beta through a novel cis-acting element (-211/-203). PD98059, which inhibits mitogen-activated protein kinase kinase/extracellular regulated kinase (MEK/ERK) attenuates IL-1beta-inducible phosphorylation of extracellular signal-regulated kinase 1/2 and mitogen and stress-activated protein kinases 1/2; and reduces levels of phosphorylated and acetylated histone H3. Histone deacetylase inhibition enhances EGR-1 transcription in response to cytokine. Conversely, suppression of histone modification with mitogen and stress-activated protein kinase 1/2 short interfering RNA, or the histone H3 acetyltransferase inhibitor Garcinol, inhibits IL-1beta-inducible EGR-1 transcription. EGR-1 interacts with the acetyltransferase p300. Acetylated H3 and phosphorylated H3 are enriched at the promoter of EGR-1; and EGR-1 is enriched at the promoters of tissue factor and plasminogen activator inhibitor 1 in response to IL-1beta, and attenuated by PD98059, Garcinol, and mitogen and stress-activated protein kinase 1/2 short interfering RNA. CONCLUSIONS IL-1beta induction of EGR-1 transcription involves histone H3 phosphorylation, acetylation, and autoregulation by EGR-1.
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Affiliation(s)
- Bo Wang
- Centre for Vascular Research, University of New South Wales, Sydney NSW 2052, Australia
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11
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Tan NY, Midgley VC, Kavurma MM, Santiago FS, Luo X, Peden R, Fahmy RG, Berndt MC, Molloy MP, Khachigian LM. Angiotensin II-inducible platelet-derived growth factor-D transcription requires specific Ser/Thr residues in the second zinc finger region of Sp1. Circ Res 2008; 102:e38-51. [PMID: 18258854 DOI: 10.1161/circresaha.107.167395] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [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] [Indexed: 11/16/2022]
Abstract
Sp1, the first identified and cloned transcription factor, regulates gene expression via multiple mechanisms including direct protein-DNA interactions, protein-protein interactions, chromatin remodeling, and maintenance of methylation-free CpG islands. Sp1 is itself regulated at different levels, for example, by glycosylation, acetylation, and phosphorylation by kinases such as the atypical protein kinase C-zeta. Although Sp1 controls the basal and inducible regulation of many genes, the posttranslational processes regulating its function and their relevance to pathology are not well understood. Here we have used a variety of approaches to identify 3 amino acids (Thr668, Ser670, and Thr681) in the zinc finger domain of Sp1 that are modified by PKC-zeta and have generated novel anti-peptide antibodies recognizing the PKC-zeta-phosphorylated form of Sp1. Angiotensin II, which activates PKC-zeta phosphorylation (at Thr410) via the angiotensin II type 1 receptor, stimulates Sp1 phosphorylation and increases Sp1 binding to the platelet-derived growth factor-D promoter. All 3 residues in Sp1 (Thr668, Ser670, and Thr681) are required for Sp1-dependent platelet-derived growth factor-D activation in response to angiotensin II. Immunohistochemical analysis revealed that phosphorylated Sp1 is expressed in smooth muscle cells of human atherosclerotic plaques and is dynamically expressed together with platelet-derived growth factor-D in smooth muscle cells of the injured rat carotid artery wall. This study provides new insights into the regulatory mechanisms controlling the PKC-zeta-phospho-Sp1 axis and angiotensin II-inducible gene expression.
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Affiliation(s)
- Nicole Y Tan
- Centre for Vascular Research, School of Medical Sciences, University of New South Wales, Sydney, Australia
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12
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Santiago FS, Ishii H, Shafi S, Khurana R, Kanellakis P, Bhindi R, Ramirez MJ, Bobik A, Martin JF, Chesterman CN, Zachary IC, Khachigian LM. Yin Yang-1 inhibits vascular smooth muscle cell growth and intimal thickening by repressing p21WAF1/Cip1 transcription and p21WAF1/Cip1-Cdk4-cyclin D1 assembly. Circ Res 2007; 101:146-55. [PMID: 17556661 DOI: 10.1161/circresaha.106.145235] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [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] [Indexed: 11/16/2022]
Abstract
Vascular injury initiates a cascade of phenotype-altering molecular events. Transcription factor function in this process, particularly that of negative regulators, is poorly understood. We demonstrate here that the forced expression of the injury-inducible GLI-Krüppel zinc finger protein Yin Yang-1 (YY1) inhibits neointima formation in human, rabbit and rat blood vessels. YY1 inhibits p21(WAF1/Cip1) transcription, prevents assembly of a p21(WAF1/Cip1)-cdk4-cyclin D1 complex, and blocks downstream pRb(Ser249/Thr252) phosphorylation and expression of PCNA and TK-1. Conversely, suppression of endogenous YY1 elevates levels of p21(WAF1/Cip1), PCNA, pRb(Ser249/Thr252) and TK-1, and increases intimal thickening. YY1 binds Sp1 and prevents its occupancy of a distinct element in the p21(WAF1/Cip1) promoter without YY1 itself binding the promoter. Additionally, YY1 induces ubiquitination and proteasome-dependent degradation of p53, decreasing p53 immunoreactivity in the artery wall. These findings define a new role for YY1 as both an inducer of p53 instability in smooth muscle cells, and an indirect repressor of p21(WAF1/Cip1) transcription, p21(WAF1/Cip1)-cdk4-cyclin D1 assembly and intimal thickening.
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Affiliation(s)
- Fernando S Santiago
- Centre for Vascular Research, Department of Pathology, University of New South Wales, and Department of Haematology, The Prince of Wales Hospital, Sydney, NSW, Australia
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13
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Liu MY, Eyries M, Zhang C, Santiago FS, Khachigian LM. Inducible platelet-derived growth factor D-chain expression by angiotensin II and hydrogen peroxide involves transcriptional regulation by Ets-1 and Sp1. Blood 2005; 107:2322-9. [PMID: 16189269 DOI: 10.1182/blood-2005-06-2377] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [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: 01/23/2023] Open
Abstract
Platelet-derived growth factor D-chain (PDGF-D) is the newest member of the PDGF family of mitogens and chemoattractants expressed in a wide variety of cell types, including vascular smooth muscle cells (SMCs). The molecular mechanisms regulating PDGF-D transcription are not known. Primer extension analysis mapped a single transcriptional start site to the ccAGCGC motif with several potential Ets motifs located upstream. Ets-1, but not Ets-1 bearing only the DNA-binding domain, activates the PDGF-D promoter and mRNA expression in SMCs. Ets site D3 ((-470)GGAT(-467)) is singly required for basal and Ets-1-inducible PDGF-D promoter-dependent expression. D3 supports the interaction of endogenous and recombinant Ets-1 and Sp1. Sp1, like Ets-1, induces PDGF-D transcription and mRNA expression, which is blocked by mutant Ets-1. H2O2 stimulates Ets-1, but not Sp1, and activates D3-dependent PDGF-D transcription. Ets-1 and Sp1 siRNA block peroxide-inducible PDGF-D expression. Angiotensin II (ATII) induction of PDGF-D and Ets-1 was blocked by prior incubation of the cells with PEG-catalase, but not BSA, indicating that ATII-inducible Ets-1 and PDGF-D expression is mediated via H2O2. Thus, 2 separate trans-acting factors regulate PDGF-D transcription, alone and in response to oxidative stress.
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Affiliation(s)
- Mary Yanxia Liu
- Centre for Vascular Research, Department of Pathology, University of New South Wales, Sydney NSW 2052 Australia
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14
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Santiago FS, Khachigian LM. Ets-1 stimulates platelet-derived growth factor A-chain gene transcription and vascular smooth muscle cell growth via cooperative interactions with Sp1. Circ Res 2004; 95:479-87. [PMID: 15297375 DOI: 10.1161/01.res.0000141135.36279.67] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [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] [Indexed: 11/16/2022]
Abstract
The platelet-derived growth factor (PDGF) family of ligands (composed of A-, B-, C-, and D-chains), potent mitogens, and chemoattractants for cells of mesenchymal origin has been implicated in numerous vascular pathologies involving smooth muscle cell (SMC) hyperplasia. Understanding the molecular mechanisms mediating PDGF transcription would provide new insights into strategies to control PDGF-dependent pathophysiologic processes. We demonstrated previously that PDGF-A expression is under the positive regulatory influence of Sp1, Sp3, and Egr-1 and is negatively controlled by GCF2, NF-1(X), and WT-1. In this article, we demonstrate that Ets-1 induces PDGF-A expression in primary rat aortic SMCs at the level of transcription and mRNA expression. Electrophoretic mobility shift, supershift, and mutational analyses revealed a functional role for the (-555)TTCC(-552) motif in the PDGF-A promoter that binds endogenous Ets-1. Chromatin immunoprecipitation analysis showed the interaction of endogenous and exogenous Ets-1 or glutathione S-transferase-tagged Ets-1, bearing only the DNA-binding domain with the authentic PDGF-A promoter. Conversely, dominant-negative mutant of Ets-1 blocked the promoter interaction of endogenous Ets-1. Overexpression of Ets-1 but not the mutant form of Ets-1 activates the PDGF-A promoter cooperatively with Sp1. Sp1, which interacts with Ets-1, failed to induce PDGF-A promoter-dependent expression if the promoter contained a site-specific mutation in this novel Ets-binding site. Small interfering RNA to Ets-1 and Sp1 blocked PDGF-BB- and serum-inducible PDGF-A expression. SMC growth was stimulated by Ets-1 and Sp1 separately and further increased by both factors together. Ets-1-inducible mitogenesis is blocked by antibodies neutralizing PDGF-A and involves activation of the PDGF alpha-receptor, which binds PDGF-A. These findings identify a functional cis-acting element for Ets-1 in the PDGF-A promoter and demonstrate that Sp1 and Ets-1 cooperatively activate PDGF-A transcription in vascular SMCs.
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Affiliation(s)
- Fernando S Santiago
- Centre for Vascular Research, The University of New South Wales, and the Department of Haematology, The Prince of Wales Hospital, Sydney, Australia
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15
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de Mestre AM, Khachigian LM, Santiago FS, Staykova MA, Hulett MD. Regulation of Inducible Heparanase Gene Transcription in Activated T Cells by Early Growth Response 1. J Biol Chem 2003; 278:50377-85. [PMID: 14522979 DOI: 10.1074/jbc.m310154200] [Citation(s) in RCA: 65] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cleavage of heparan sulfate by the beta-D-endoglucuronidase heparanase (HPSE) is a fundamental event in a number of important physiological processes including inflammation, wound healing, and angiogenesis. HPSE activity has also been directly correlated with pathological conditions such as tumor growth and metastasis and autoimmune disease. The tight regulation of HPSE expression and function is critical to ensure homeostasis of the normal physiological processes to which it contributes and to prevent imbalance toward pathological situations. Little is known about the transcriptional mechanisms that regulate HPSE expression. In this study we have shown human HPSE gene transcription in Jurkat T cells is induced upon activation. Functional analysis of the HPSE promoter has identified a 280-bp region that is highly inducible. Mutation studies together with supershift experiments have identified a 4-bp motif that binds the transcription factor early growth response-1 (Egr1) and is critical in regulating inducible HPSE gene transcription. Furthermore, the overexpression of Egr1 resulted in the enhanced activation of the HPSE promoter. By using MAPK pathway inhibitors, we have also shown that inducible expression of HPSE mRNA and the activity of the 280-bp HPSE promoter element are dependent on the ERK1/2 (MEK1/2) pathway. This pathway is critical for induction of Egr1 expression at both the mRNA and protein level in T cells, an observation that provides further support to Egr1 playing an important role as a key activator of HPSE expression. In addition, HPSE and Egr1 were shown to co-localize by immunohistochemistry to invading mononuclear leukocytes in actively induced experimental autoimmune encephalomyelitis in rats. These findings provide the first insight into the mechanisms controlling inducible transcription of the HPSE gene, and could represent an important lead into understanding how HPSE expression is deregulated in metastatic tumor cells.
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Affiliation(s)
- Amanda M de Mestre
- Cancer and Vascular Biology Group, John Curtin School of Medical Research, Australian National University, Acton ACT 2601
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16
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Francis DJ, Parish CR, McGarry M, Santiago FS, Lowe HC, Brown KJ, Bingley JA, Hayward IP, Cowden WB, Campbell JH, Campbell GR, Chesterman CN, Khachigian LM. Blockade of vascular smooth muscle cell proliferation and intimal thickening after balloon injury by the sulfated oligosaccharide PI-88: phosphomannopentaose sulfate directly binds FGF-2, blocks cellular signaling, and inhibits proliferation. Circ Res 2003; 92:e70-7. [PMID: 12690039 DOI: 10.1161/01.res.0000071345.76095.07] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [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] [Indexed: 11/16/2022]
Abstract
Percutaneous transluminal coronary angioplasty is a frequently used interventional technique to reopen arteries that have narrowed because of atherosclerosis. Restenosis, or renarrowing of the artery shortly after angioplasty, is a major limitation to the success of the procedure and is due mainly to smooth muscle cell accumulation in the artery wall at the site of balloon injury. In the present study, we demonstrate that the antiangiogenic sulfated oligosaccharide, PI-88, inhibits primary vascular smooth muscle cell proliferation and reduces intimal thickening 14 days after balloon angioplasty of rat and rabbit arteries. PI-88 reduced heparan sulfate content in the injured artery wall and prevented change in smooth muscle phenotype. However, the mechanism of PI-88 inhibition was not merely confined to the antiheparanase activity of this compound. PI-88 blocked extracellular signal-regulated kinase-1/2 (ERK1/2) activity within minutes of smooth muscle cell injury. It facilitated FGF-2 release from uninjured smooth muscle cells in vitro, and super-released FGF-2 after injury while inhibiting ERK1/2 activation. PI-88 inhibited the decrease in levels of FGF-2 protein in the rat artery wall within 8 minutes of injury. PI-88 also blocked injury-inducible ERK phosphorylation, without altering the clotting time in these animals. Optical biosensor studies revealed that PI-88 potently inhibited (Ki 10.3 nmol/L) the interaction of FGF-2 with heparan sulfate. These findings show for the first time the capacity of this sulfated oligosaccharide to directly bind FGF-2, block cellular signaling and proliferation in vitro, and inhibit injury-induced smooth muscle cell hyperplasia in two animal models. As such, this study demonstrates a new role for PI-88 as an inhibitor of intimal thickening after balloon angioplasty. The full text of this article is available online at http://www.circresaha.org.
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MESH Headings
- Angioplasty, Balloon/adverse effects
- Animals
- Binding, Competitive
- Carotid Arteries/drug effects
- Carotid Arteries/metabolism
- Carotid Arteries/pathology
- Carotid Artery Injuries/etiology
- Carotid Artery Injuries/pathology
- Carotid Artery Injuries/prevention & control
- Cell Division/drug effects
- Enzyme Activation/drug effects
- Fibroblast Growth Factor 2/metabolism
- Heparitin Sulfate/metabolism
- Male
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinases/metabolism
- Models, Biological
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Oligosaccharides/metabolism
- Oligosaccharides/pharmacology
- Rabbits
- Rats
- Rats, Wistar
- Signal Transduction/drug effects
- Tunica Intima/drug effects
- Tunica Intima/metabolism
- Tunica Intima/pathology
- Tunica Media/drug effects
- Tunica Media/metabolism
- Tunica Media/pathology
- Whole Blood Coagulation Time
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Affiliation(s)
- Douglas J Francis
- Division of Immunology and Genetics, John Curtin School of Medical Research, Australian National University, Canberra, Australia
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17
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Abstract
The regulatory mechanisms mediating basal and inducible platelet-derived growth factor (PDGF)-A expression have been the focus of intense recent investigation, but repression of PDGF-A expression is largely unexplored. Here we isolated a nuclear factor that interacts with the proximal region of the PDGF-A promoter using bulk binding assays and chromatography techniques. Peptide mass fingerprint and supershift analysis revealed this DNA-binding protein to be NF1/X. NF1/X repressed PDGF-A promoter-dependent transcription and endogenous mRNA expression, which was reversible by oligonucleotide decoys bearing an NF1/X-binding site. Mutation in the DNA-binding domain of NF1/X abolished its repression of PDGF-A promoter. NF1/X antagonized the activity of a known activator of the PDGF-A chain, Sp1, by inhibiting its occupancy of the proximal PDGF-A promoter. NF1/X physically and specifically interacts with Sp1 via its subtype-specific domain and blocks Sp1 induction of the promoter. NF1/X residues 311-416 mediated NF1/X suppression of basal PDGF-A transcription, whereas residues 243-416 were required for NF1/X repression of Sp1-inducible promoter activity. These findings demonstrate that repression of PDGF-A gene transcription is governed by interplay between NF1/X and Sp1.
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Affiliation(s)
| | | | - Levon M. Khachigian
- Centre for Thrombosis and Vascular Research, Department of Pathology, The University of New South Wales and Department of Haematology, Prince of Wales Hospital, Sydney, Australia
Corresponding author e-mail:
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18
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Santiago FS, Khachigian LM. Nucleic acid based strategies as potential therapeutic tools: mechanistic considerations and implications to restenosis. J Mol Med (Berl) 2001; 79:695-706. [PMID: 11862313 DOI: 10.1007/s001090100272] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2001] [Accepted: 07/02/2001] [Indexed: 11/29/2022]
Abstract
The capacity of DNA to bind RNA via Watson-Crick base-pairing is fundamental to antisense oligonucleotide strategies to inhibit gene expression, and is a property that has been exploited by bioengineers in the generation of catalytic molecules such as ribozymes, ribozyme subtypes, and more recently DNAzymes. This review describes the evolution of these gene-specific agents and summarizes recent efforts to inhibit smooth muscle cell growth with these molecules as candidate therapeutic tools in restenosis.
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MESH Headings
- Animals
- Base Pairing
- Coronary Restenosis/genetics
- Coronary Restenosis/prevention & control
- DNA/genetics
- DNA, Catalytic/genetics
- DNA, Catalytic/therapeutic use
- DNA, Single-Stranded/genetics
- DNA, Single-Stranded/therapeutic use
- Gene Expression Regulation
- Gene Targeting
- Humans
- Muscle, Smooth, Vascular/physiology
- Nucleic Acids/genetics
- Oligodeoxyribonucleotides, Antisense/genetics
- Oligodeoxyribonucleotides, Antisense/therapeutic use
- RNA/genetics
- RNA, Catalytic/genetics
- RNA, Catalytic/therapeutic use
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Affiliation(s)
- F S Santiago
- Centre for Thrombosis and Vascular Research, School of Pathology, University of New South Wales, Sydney NSW 2052, Australia
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19
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Santiago FS, Lowe HC, Bobryshev YV, Khachigian LM. Induction of the transcriptional repressor Yin Yang-1 by vascular cell injury. Autocrine/paracrine role of endogenous fibroblast growth factor-2. J Biol Chem 2001; 276:41143-9. [PMID: 11487577 DOI: 10.1074/jbc.m104913200] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [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: 11/06/2022] Open
Abstract
Yin Yang-1 (YY1) is a multifunctional transcription factor that can repress the expression of many growth factor, hormone, and cytokine genes implicated in atherogenesis. YY1 expression is activated in rat vascular smooth muscle cells shortly after injury. YY1 DNA binding activity paralleled elevated protein levels in the nucleus. Smooth muscle cell injury triggered the rapid extracellular release of immunoreactive fibroblast growth factor-2 (FGF-2). YY1 induction after injury was blocked by neutralizing antibodies directed against FGF-2. This growth factor increased YY1 mRNA and protein expression and stimulated YY1 binding and transcriptional activity. Overexpression of YY1 inhibited smooth muscle cell replication. Immunohistochemical analysis demonstrated YY1 staining in medial smooth muscle cells, coincident with FGF-2 expression. Proliferating cell nuclear antigen staining, in contrast, was confined mainly to the atherosclerotic intima. This is the first demonstration that YY1 is induced by either injury or FGF-2, is differentially expressed in normal and diseased human arteries, and that its overexpression inhibits vascular smooth muscle but not endothelial cell replication.
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Affiliation(s)
- F S Santiago
- Center for Thrombosis and Vascular Research, The University of New South Wales, Sydney, New South Wales 2052, Australia
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20
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Abstract
Apoptosis of smooth muscle cells (SMC) in atherosclerotic vessels can destabilize the atheromatus plaque and result in rupture, thrombosis, and sudden death. In efforts to understand the molecular processes regulating apoptosis in this cell type, we have defined a novel mechanism involving the ubiquitously expressed transcription factor Sp1. Subtypes of SMC expressing abundant levels of Sp1 produce the death agonist, Fas ligand (FasL) and undergo greater spontaneous apoptosis. Sp1 activates the FasL promoter via a distinct nucleotide recognition element whose integrity is crucial for inducible expression. Inducible FasL promoter activation is also inhibited by a dominant-negative form of Sp1. Increased SMC apoptosis is preceded by Sp1 phosphorylation, increased FasL transcription, and the autocrine/paracrine engagement of FasL with its cell-surface receptor, Fas. Inducible FasL transcription and apoptosis are blocked by dominant-negative protein kinase C-zeta, whose wild-type counterpart phosphorylates Sp1. Thus, Sp1 phosphorylation is a proapoptotic transcriptional event in vascular SMC and, given the wide distribution of this housekeeping transcription factor, may be a common regulatory theme in apoptotic signal transduction.
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Affiliation(s)
- M M Kavurma
- Centre for Thrombosis and Vascular Research, The University of New South Wales, Sydney NSW 2052, Australia
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21
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Santiago FS, Lowe HC, Kavurma MM, Chesterman CN, Baker A, Atkins DG, Khachigian LM. New DNA enzyme targeting Egr-1 mRNA inhibits vascular smooth muscle proliferation and regrowth after injury. Nat Med 1999; 5:1264-9. [PMID: 10545992 DOI: 10.1038/15215] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.0] [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: 11/08/2022]
Abstract
Early growth response factor-1 (Egr-1) binds to the promoters of many genes whose products influence cell movement and replication in the artery wall. Here we targeted Egr-1 using a new class of DNA-based enzyme that specifically cleaved Egr-1 mRNA, blocked induction of Egr-1 protein, and inhibited cell proliferation and wound repair in culture. The DNA enzyme also inhibited Egr-1 induction and neointima formation after balloon injury to the rat carotid artery wall. These findings demonstrate the utility of DNA enzymes as biological tools to delineate the specific functions of a given gene, and implicate catalytic nucleic acid molecules composed entirely of DNA as potential therapeutic agents.
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Affiliation(s)
- F S Santiago
- Centre for Thrombosis and Vascular Research, The University of New South Wales and Prince of Wales Hospital, Sydney, Australia
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22
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Silverman ES, Khachigian LM, Santiago FS, Williams AJ, Lindner V, Collins T. Vascular smooth muscle cells express the transcriptional corepressor NAB2 in response to injury. Am J Pathol 1999; 155:1311-7. [PMID: 10514413 PMCID: PMC1867007 DOI: 10.1016/s0002-9440(10)65233-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The early growth response 1 (Egr-1 or NGFI-A) gene product is a zinc finger protein transcription factor which has been implicated in the regulation of genes differentially expressed during the development of vascular disease. Egr-1 activity is regulated by alterations in the amount of protein, as well as protein-protein interactions with positive and negative transcriptional cofactors. NGFI-A-binding protein 2 (NAB2) is an example of a negative transcriptional cofactor capable of binding directly to Egr-1 and repressing Egr-1-mediated transcription. In this study, we show that NAB2 is rapidly and transiently expressed in vascular smooth muscle cells (VSMC) in response to the model agonist phorbol 12-myristate 13-acetate (PMA). This induction occurs at the protein as well as mRNA level, and the time course of induction trails closely behind that of Egr-1. NAB2 expression in VSMC is capable of inhibiting Egr-1 dependent gene expression in response to either PMA or fibroblastic growth factor-2 (FGF-2). In an in vivo model of mechanical arterial injury NAB2 levels also increase transiently in VSMC at a time when Egr-1 is elevated. It is possible that NAB2 is part of a negative-feedback mechanism which serves to down-regulate Egr-1-mediated gene transcription in injured VSMC.
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MESH Headings
- Animals
- Blotting, Northern
- Blotting, Western
- Cattle
- Cell Division/genetics
- Cell Movement/genetics
- Cell Nucleus/metabolism
- Cells, Cultured
- DNA-Binding Proteins/metabolism
- Early Growth Response Protein 1
- Fibroblast Growth Factor 2/pharmacology
- Gene Expression Regulation/drug effects
- Immediate-Early Proteins
- In Situ Hybridization
- Male
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/injuries
- Muscle, Smooth, Vascular/metabolism
- Neoplasm Proteins
- Platelet-Derived Growth Factor/metabolism
- RNA, Messenger/metabolism
- Rats
- Repressor Proteins/biosynthesis
- Tetradecanoylphorbol Acetate/pharmacology
- Time Factors
- Transcription Factors/metabolism
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Affiliation(s)
- E S Silverman
- Pulmonary and Critical Care Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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23
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Santiago FS, Atkins DG, Khachigian LM. Vascular smooth muscle cell proliferation and regrowth after mechanical injury in vitro are Egr-1/NGFI-A-dependent. Am J Pathol 1999; 155:897-905. [PMID: 10487847 PMCID: PMC1866910 DOI: 10.1016/s0002-9440(10)65189-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Smooth muscle cell (SMC) proliferation is a key event in renarrowing of blood vessels after balloon angioplasty. Mechanical injury imparted to the arterial wall in experimental models induces the expression of the immediate-early gene, egr-1. Egr-1 binds to and activates expression from the proximal promoters of multiple genes whose products can, in turn, influence the vascular response to injury. Here, we used antisense strategies in vitro to inhibit rat vascular SMC proliferation by directly targeting Egr-1. A series of phosphorothioate antisense oligonucleotides of 15 base length and complementary to various theoretically accessible regions within Egr-1 mRNA were synthesized and assessed for their ability to selectively inhibit SMC proliferation in an Egr-1-dependent manner. Western blot analysis revealed that two oligonucleotides, AS2 and E11, inhibited Egr-1 synthesis in cells exposed to serum without affecting levels of the zinc finger protein Sp1. AS2 and E11 inhibited serum-inducible [(3)H]thymidine incorporation into DNA, as well as serum stimulation of total cell numbers. Size-matched phosphorothioate oligonucleotides with random, scrambled, sense or mismatch sequences failed to inhibit. Antisense Egr-1 inhibition was nontoxic and reversible. These oligonucleotides also inhibited SMC regrowth after mechanical injury in vitro. Egr-1 thus plays a key regulatory role in SMC proliferation and repair following injury.
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MESH Headings
- Animals
- Binding Sites
- Blood Proteins/pharmacology
- Blotting, Western
- Cell Division/drug effects
- Cells, Cultured
- DNA-Binding Proteins/antagonists & inhibitors
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/physiology
- Early Growth Response Protein 1
- Fluorescein-5-isothiocyanate
- Gene Expression/drug effects
- Immediate-Early Proteins
- Microscopy, Fluorescence
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/injuries
- Muscle, Smooth, Vascular/metabolism
- Nucleic Acid Conformation
- Nucleic Acid Synthesis Inhibitors/pharmacology
- Oligonucleotides, Antisense/metabolism
- Oligonucleotides, Antisense/pharmacokinetics
- Phosphorus Radioisotopes
- Platelet-Derived Growth Factor/biosynthesis
- RNA, Messenger/drug effects
- Rats
- Thionucleotides/pharmacokinetics
- Thionucleotides/pharmacology
- Time Factors
- Transcription Factors/antagonists & inhibitors
- Transcription Factors/genetics
- Transcription Factors/physiology
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Affiliation(s)
- F S Santiago
- Centre for Thrombosis and Vascular Research, The University of New South Wales, Sydney, Australia Sydney, Australia
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24
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Khachigian LM, Santiago FS, Rafty LA, Chan OL, Delbridge GJ, Bobik A, Collins T, Johnson AC. GC factor 2 represses platelet-derived growth factor A-chain gene transcription and is itself induced by arterial injury. Circ Res 1999; 84:1258-67. [PMID: 10364563 DOI: 10.1161/01.res.84.11.1258] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Platelet-derived growth factor (PDGF) is a mitogen and chemoattractant for a wide variety of cell types. The genes encoding PDGF A chain (PDGF-A) and PDGF B chain (PDGF-B) reside on separate chromosomes and are independently regulated at the level of transcription. Regulatory events underlying inducible PDGF-A expression have been the focus of much investigation. However, mechanisms that inhibit transcription of this gene are not well understood. In this study, we report the capacity of a newly cloned DNA binding factor, GC factor 2 (GCF2), to repress expression driven by the human PDGF-A promoter. 5' Deletion and transient cotransfection analysis in vascular endothelial cells revealed that GCF2 repression is mediated by a nucleotide region located in the proximal region of the PDGF-A promoter. Electrophoretic mobility shift assays demonstrate that GCF2 binds to this region in a specific and dose-dependent manner. Interestingly, the site bound by GCF2 overlaps those for specificity protein-1 (Sp1) and early growth response factor-1 (Egr-1), zinc finger transcription factors that direct basal and inducible expression of the PDGF-A gene. Gel shift experiments revealed that GCF2 competes with these factors for interaction with the PDGF-A promoter. Overexpression of GCF2 suppressed endogenous PDGF-A expression in vascular endothelial cells and smooth muscle cells. GCF2 was induced on mechanical injury of cells in culture as well as after balloon injury of the rat carotid artery wall. Time course studies revealed the sustained induction of GCF2 after injury while PDGF-A levels sharply returned to baseline. Smooth muscle cell proliferation was inhibited by GCF2, an effect reversed by the addition of exogenous PDGF-AA. These findings demonstrate negative regulation of PDGF-A expression by GCF2. This is the first report of the induction of an endogenous transcriptional repressor in the rat vessel wall.
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MESH Headings
- Animals
- Aorta/injuries
- Aorta/pathology
- Cattle
- Cells, Cultured
- DNA-Binding Proteins/genetics
- Endothelium, Vascular/injuries
- Endothelium, Vascular/pathology
- G-Box Binding Factors
- Humans
- Muscle, Smooth, Vascular/injuries
- Muscle, Smooth, Vascular/pathology
- Platelet-Derived Growth Factor/genetics
- Promoter Regions, Genetic
- Protein Binding
- Rats
- Rats, Sprague-Dawley
- Repressor Proteins/genetics
- Stress, Mechanical
- Transcription Factors/genetics
- Transcription, Genetic
- Zinc Fingers
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Affiliation(s)
- L M Khachigian
- Centre for Thrombosis and Vascular Research, The University of New South Wales, Department of Haematology, Prince of Wales Hospital, Sydney, Australia.
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Santiago FS, Lowe HC, Day FL, Chesterman CN, Khachigian LM. Early growth response factor-1 induction by injury is triggered by release and paracrine activation by fibroblast growth factor-2. Am J Pathol 1999; 154:937-44. [PMID: 10079272 PMCID: PMC1866428 DOI: 10.1016/s0002-9440(10)65341-2] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cell migration and proliferation that follows injury to the artery wall is preceded by signaling and transcriptional events that converge at the promoters of multiple genes whose products can influence formation of the neointima. Transcription factors, such as early growth response factor-1 (Egr-1), with nucleotide recognition elements in the promoters of many pathophysiologically relevant genes, are expressed at the endothelial wound edge within minutes of injury. The mechanisms underlying the inducible expression of Egr-1 in this setting are not clear. Understanding this process would provide important mechanistic insights into the earliest events in the response to injury. In this report, we demonstrate that fibroblast growth factor-2 (FGF-2) is released by injury and that antibodies to FGF-2 almost completely abrogate the activation and nuclear accumulation of Egr-1. FGF-2-inducible egr-1-promoter-dependent expression is blocked by PD98059, a specific inhibitor of mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK)-1/2 (MEK-1/2), as well as by dominant negative mutants of ERK-1/2. Inducible ERK phosphorylation after injury is dependent on release and stimulation by endogenous FGF-2. Antisense oligonucleotides directed at egr-1 mRNA suggest that Egr-1 plays a necessary role in endothelial repair after denudation of the monolayer. These findings demonstrate that inducible Egr-1 expression after injury is contingent on the release and paracrine action of FGF-2.
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Affiliation(s)
- F S Santiago
- Centre for Thrombosis and Vascular Research, School of Pathology, The University of New South Wales, Sydney, Australia
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Khachigian LM, Santiago FS, Delbridge GJ, Chesterman CN. 3.P.318 Endothelial injury and transcriptional activation: bFGF induction of Egr-1 and PDGF-A. Atherosclerosis 1997. [DOI: 10.1016/s0021-9150(97)89392-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Point mutations in the K-ras gene are frequently observed in a variety of human malignancies, including colorectal and pancreatic cancers. In this paper, we describe a sensitive procedure for the detection of point mutations of codon 12 of the K-ras gene. The assay employs a single-tube enriched PCR procedure, coupled to colorimetric detection. In the enriched PCR procedure, the first round of amplification introduces a restriction enzyme site in the wild type, but not in mutant K-ras PCR product. The wild type products are then digested and the second round of PCR enriches for the mutant sequences by amplifying the resistant products. The second round of amplification allows the incorporation of biotin and a substrate binding tag at opposite ends of the mutant product, thus allowing detection of the product by a simple colorimetric assay. The assay has been validated using DNA from a variety of cell lines known to contain either mutant or wild type K-ras. Under these conditions, the assay has proved both reproducible and sensitive, with the ability to detect one mutant molecule in a background of 1000 wild type molecules. The assay allowed discrimination of mutant from wild type K-ras in samples from colonic adenocarcinomas and normal colonic mucosa. The use of a colorimetric detection system reduces observer bias and facilitates analysis of large numbers of samples. As such, the assay may have specific application in the sensitive detection of K-ras mutations in a variety of clinical samples.
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Affiliation(s)
- F S Santiago
- RW Johnson Pharmaceutical Research Institute, St. Vincent's Hospital, Sydney, Australia
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Abstract
A number of minimised hammerhead ribozymes (minizymes) which lack stem II have been kinetically characterised. These minizymes display optimal cleavage activity at temperatures around 37 degrees C. The cleavage reactions of the minizymes are first order in hydroxide ion concentration up to around pH 9.3 above which the cleavage rate constants decline rapidly. The reactions show a biphasic dependence on magnesium-ion concentration; one of the interactions has an apparent dissociation constant of around 20 mM while the other appears to be very weak, showing no sign of saturation at 200 mM MgCl2. The minizymes are significantly less active than comparable, full-size ribozymes when cleaving short substrates. However, at a particular site in a transcribed TAT gene from HIV-1, minizymes are more effective than ribozymes.
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Affiliation(s)
- P Hendry
- CSIRO, Division of Biomolecular Engineering, North Ryde, NSW, Australia
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Abstract
Hammerhead ribozymes cleave RNA substrates containing the UX sequence, where X = U, C or A, embedded within sequences which are complementary to the hybridising 'arms' of the ribozyme. In this study we have replaced the RNA in the hybridising arms of the ribozyme with DNA, and the resulting ribozyme is many times more active than its precursor. In turnover-kinetics experiments with a 13-mer RNA substrate, the kcat/Km ratios are 10 and 150 microM-1min-1 for the RNA- and DNA-armed ribozymes, respectively. The effect is due mainly to differences in kcat. In independent experiments where the cleavage step is rate-limiting, the DNA-armed ribozyme cleaves the substrate with a rate constant more than 3 times greater than the all-RNA ribozyme. DNA substrates containing a ribocytidine at the cleavage site have been shown to be cleaved less efficiently than their all-RNA analogues; again however, the DNA-armed ribozyme is more effective than the all-RNA ribozyme against such DNA substrates. These results demonstrate that there are no 2'-hydroxyl groups in the arms of the ribozyme that are required for cleavage; and that the structure of the complex formed by the DNA-armed ribozyme with its substrate is more favourable for cleavage than that formed by the all-RNA ribozyme and its substrate.
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Affiliation(s)
- P Hendry
- CSIRO, Division of Biomolecular Engineering, North Ryde, NSW, Australia
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Romana LK, Santiago FS, Reeves PR. High level expression and purification of dthymidine diphospho-D-glucose 4,6-dehydratase (rfbB) from Salmonella serovar typhimurium LT2. Biochem Biophys Res Commun 1991; 174:846-52. [PMID: 1993076 DOI: 10.1016/0006-291x(91)91495-x] [Citation(s) in RCA: 17] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The rfbB gene (dThymidine-diphospho-D-glucose-4,6-dehydratase) from Salmonella serovar typhimurium LT2 was cloned and over-expressed using the T7 RNA polymerase/promoter system. The expressed protein, which represents almost 10% of the total cellular protein was purified 14-fold. dTDP-D-glucose 4,6-dehydratase is a homodimer of 43 kDa subunits, is highly specific for dTDP-D-glucose and shows a Km of 427 microM and Vmax of 0.93 mu moles min-1 micrograms-1 of protein for dTDP-D-glucose. The N-terminal analysis confirmed the start position of the gene in the DNA sequence. Complete deactivation of the enzyme by the addition of p-chloromercurisulfonic acid and total reactivation by the addition of mercaptoethanol, co-factor NAD+ and cystein showed that a -SH group of the cysteine is involved in the catalytic site.
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Affiliation(s)
- L K Romana
- Department of Microbiology, University of Sydney, N.S.W., Australia
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