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Khozeimeh Sarbisheh E, Summers KL, Salih AK, Cotelesage JJH, Zimmerling A, Pickering IJ, George GN, Price EW. Radiochemical, Computational, and Spectroscopic Evaluation of High-Denticity Desferrioxamine Derivatives DFO2 and DFO2p toward an Ideal Zirconium-89 Chelate Platform. Inorg Chem 2023; 62:2637-2651. [PMID: 36716427 DOI: 10.1021/acs.inorgchem.2c03573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Desferrioxamine (DFO) has long been considered the gold standard chelator for incorporating [89Zr]Zr4+ in radiopharmaceuticals for positron emission tomography (PET) imaging. To improve the stability of DFO with zirconium-89 and to expand its coordination sphere to enable binding of large therapeutic radiometals, we have synthesized the highest denticity DFO derivatives to date: dodecadentate DFO2 and DFO2p. In this study, we describe the synthesis and characterization of a novel DFO-based chelator, DFO2p, which is comprised of two DFO strands connected by an p-NO2-phenyl linker and therefore contains double the chelating moieties of DFO (potential coordination number up to 12 vs 6). The chelator DFO2p offers an optimized synthesis comprised of only a single reaction step and improves water solubility relative to DFO2, but the shorter linker reduces molecular flexibility. Both DFO2 and DFO2p, each with 6 potential hydroxamate ligands, are able to reach a more energetically favorable 8-coordinate environment for Zr(IV) than DFO. The zirconium(IV) coordination environment of these complexes were evaluated by a combination of density functional theory (DFT) calculations and synchrotron spectroscopy (extended X-ray absorption fine structure), which suggest the inner-coordination sphere of zirconium(IV) to be comprised of the outermost four hydroxamate ligands. These results also confirm a single Zr(IV) in each chelator, and the hydroxide ligands which complete the coordination sphere of Zr(IV)-DFO are absent from Zr(IV)-DFO2 and Zr(IV)-DFO2p. Radiochemical stability studies with zirconium-89 revealed the order of real-world stability to be DFO2 > DFO2p ≫ DFO. The zirconium-89 complexes of these new high-denticity chelators were found to be far more stable than DFO, and the decreased molecular flexibility of DFO2p, relative to DFO2, could explain its decreased stability, relative to DFO2.
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Affiliation(s)
- Elaheh Khozeimeh Sarbisheh
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada
| | - Kelly L Summers
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5E2, Canada
| | - Akam K Salih
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada
| | - Julien J H Cotelesage
- Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5E2, Canada
| | - Amanda Zimmerling
- Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, Saskatoon, SKS7N 5A9, Canada
| | - Ingrid J Pickering
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5E2, Canada
| | - Graham N George
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5E2, Canada
| | - Eric W Price
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SKS7N 5C9, Canada
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Summers KL, Roseman G, Schilling KM, Dolgova NV, Pushie MJ, Sokaras D, Kroll T, Harris HH, Millhauser GL, Pickering IJ, George GN. Alzheimer's Drug PBT2 Interacts with the Amyloid β 1-42 Peptide Differently than Other 8-Hydroxyquinoline Chelating Drugs. Inorg Chem 2022; 61:14626-14640. [PMID: 36073854 PMCID: PMC9957665 DOI: 10.1021/acs.inorgchem.2c01694] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although Alzheimer's disease (AD) was first described over a century ago, it remains the leading cause of age-related dementia. Innumerable changes have been linked to the pathology of AD; however, there remains much discord regarding which might be the initial cause of the disease. The "amyloid cascade hypothesis" proposes that the amyloid β (Aβ) peptide is central to disease pathology, which is supported by elevated Aβ levels in the brain before the development of symptoms and correlations of amyloid burden with cognitive impairment. The "metals hypothesis" proposes a role for metal ions such as iron, copper, and zinc in the pathology of AD, which is supported by the accumulation of these metals within amyloid plaques in the brain. Metals have been shown to induce aggregation of Aβ, and metal ion chelators have been shown to reverse this reaction in vitro. 8-Hydroxyquinoline-based chelators showed early promise as anti-Alzheimer's drugs. Both 5-chloro-7-iodo-8-hydroxyquinoline (CQ) and 5,7-dichloro-2-[(dimethylamino)methyl]-8-hydroxyquinoline (PBT2) underwent unsuccessful clinical trials for the treatment of AD. To gain insight into the mechanism of action of 8HQs, we have investigated the potential interaction of CQ, PBT2, and 5,7-dibromo-8-hydroxyquinoline (B2Q) with Cu(II)-bound Aβ(1-42) using X-ray absorption spectroscopy (XAS), high energy resolution fluorescence detected (HERFD) XAS, and electron paramagnetic resonance (EPR). By XAS, we found CQ and B2Q sequestered ∼83% of the Cu(II) from Aβ(1-42), whereas PBT2 sequestered only ∼59% of the Cu(II) from Aβ(1-42), suggesting that CQ and B2Q have a higher relative Cu(II) affinity than PBT2. From our EPR, it became clear that PBT2 sequestered Cu(II) from a heterogeneous mixture of Cu(II)Aβ(1-42) species in solution, leaving a single Cu(II)Aβ(1-42) species. It follows that the Cu(II) site in this Cu(II)Aβ(1-42) species is inaccessible to PBT2 and may be less solvent-exposed than in other Cu(II)Aβ(1-42) species. We found no evidence to suggest that these 8HQs form ternary complexes with Cu(II)Aβ(1-42).
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Affiliation(s)
- Kelly L. Summers
- Molecular and Environmental Sciences Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham Roseman
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, United States
| | - Kevin M. Schilling
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, United States
| | - Natalia V. Dolgova
- Molecular and Environmental Sciences Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - M. Jake Pushie
- Department of Surgery, University of Saskatchewan, 103 Hospital Dr, Saskatoon, Saskatchewan S7N 0W8, Canada
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Hugh H. Harris
- Department of Chemistry, University of Adelaide, South Australia 5005, Australia
| | - Glenn L. Millhauser
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, United States
| | - Ingrid J. Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham N. George
- Molecular and Environmental Sciences Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
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Pushie MJ, Summers KL, Nienaber KH, Pickering IJ, George GN. Synthesis and structural characterization of copper–cuprizone complexes. Dalton Trans 2022; 51:10361-10376. [DOI: 10.1039/d2dt01475k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The chemistry of copper with cuprizone has challenged chemists for over 70 years. We characterize the classical ‘blue’ product, containing Cu(iii) and hydrolyzed cuprizone, and a green multimeric Cu(ii) product, containing unhydrolyzed cuprizone.
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Affiliation(s)
- M. Jake Pushie
- Department of Surgery, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Kelly L. Summers
- Department of Physiology, School of Medicine, Johns Hopkins University, 725 North Wolfe Street, Baltimore, Maryland 21205, USA
| | | | - Ingrid J. Pickering
- Molecular and Environmental Sciences Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, Saskatchewan, S7N 5C9, Canada
| | - Graham N. George
- Molecular and Environmental Sciences Research Group, Department of Geological Sciences, University of Saskatchewan, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, Saskatchewan, S7N 5C9, Canada
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Rudak PT, Choi J, Parkins KM, Summers KL, Jackson DN, Foster PJ, Skaro AI, Leslie K, McAlister VC, Kuchroo VK, Inoue W, Lantz O, Haeryfar SMM. Chronic stress physically spares but functionally impairs innate-like invariant T cells. Cell Rep 2021; 35:108979. [PMID: 33852855 PMCID: PMC8112805 DOI: 10.1016/j.celrep.2021.108979] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 02/09/2021] [Accepted: 03/22/2021] [Indexed: 02/07/2023] Open
Abstract
The deleterious effects of psychological stress on mainstream T lymphocytes are well documented. However, how stress impacts innate-like T cells is unclear. We report that long-term stress surprisingly abrogates both T helper 1 (TH1)- and TH2-type responses orchestrated by invariant natural killer T (iNKT) cells. This is not due to iNKT cell death because these cells are unusually refractory to stress-inflicted apoptosis. Activated iNKT cells in stressed mice exhibit a “split” inflammatory signature and trigger sudden serum interleukin-10 (IL-10), IL-23, and IL-27 spikes. iNKT cell dysregulation is mediated by cell-autonomous glucocorticoid receptor signaling and corrected upon habituation to predictable stressors. Importantly, under stress, iNKT cells fail to potentiate cytotoxicity against lymphoma or to reduce the burden of metastatic melanoma. Finally, stress physically spares mouse mucosa-associated invariant T (MAIT) cells but hinders their TH1-/TH2-type responses. The above findings are corroborated in human peripheral blood and hepatic iNKT/MAIT cell cultures. Our work uncovers a mechanism of stress-induced immunosuppression. Invariant T cells are emergency responders to infection and cancer. Rudak et al. report that psychological stress unusually spares these innate-like T lymphocytes but alters or impairs their cytokine production and cytotoxic and/or antimetastatic capacities through a cell-autonomous, glucocorticoid receptor-dependent mechanism. This may explain certain aspects of stress-induced immunosuppression.
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Affiliation(s)
- Patrick T Rudak
- Department of Microbiology and Immunology, Western University, London, ON N6A 5C1, Canada
| | - Joshua Choi
- Department of Microbiology and Immunology, Western University, London, ON N6A 5C1, Canada
| | - Katie M Parkins
- Department of Medical Biophysics, Western University, London, ON N6A 5C1, Canada; Robarts Research Institute, Western University, London, ON N6A 5B7, Canada
| | - Kelly L Summers
- Department of Microbiology and Immunology, Western University, London, ON N6A 5C1, Canada
| | - Dwayne N Jackson
- Department of Medical Biophysics, Western University, London, ON N6A 5C1, Canada
| | - Paula J Foster
- Department of Medical Biophysics, Western University, London, ON N6A 5C1, Canada; Robarts Research Institute, Western University, London, ON N6A 5B7, Canada
| | - Anton I Skaro
- Department of Surgery, Division of General Surgery, Western University, London, ON N6A 4V2, Canada
| | - Ken Leslie
- Department of Surgery, Division of General Surgery, Western University, London, ON N6A 4V2, Canada
| | - Vivian C McAlister
- Department of Surgery, Division of General Surgery, Western University, London, ON N6A 4V2, Canada
| | - Vijay K Kuchroo
- Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Wataru Inoue
- Robarts Research Institute, Western University, London, ON N6A 5B7, Canada; Department of Physiology and Pharmacology, Western University, London, ON N6A 5C1, Canada
| | - Olivier Lantz
- Laboratoire d'Immunologie and INSERM U932, PSL University, Institut Curie, 75248 Paris Cedex 5, France
| | - S M Mansour Haeryfar
- Department of Microbiology and Immunology, Western University, London, ON N6A 5C1, Canada; Department of Surgery, Division of General Surgery, Western University, London, ON N6A 4V2, Canada; Department of Medicine, Division of Clinical Immunology and Allergy, Western University, London, ON N6A 5A5, Canada.
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5
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Summers KL, Dolgova NV, Gagnon KB, Sopasis GJ, James AK, Lai B, Sylvain NJ, Harris HH, Nichol HK, George GN, Pickering IJ. PBT2 acts through a different mechanism of action than other 8-hydroxyquinolines: an X-ray fluorescence imaging study. Metallomics 2020; 12:1979-1994. [PMID: 33169753 DOI: 10.1039/d0mt00222d] [Citation(s) in RCA: 10] [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: 12/11/2022]
Abstract
8-Hydroxyquinolines (8HQs) comprise a family of metal-binding compounds that have been used or tested for use in numerous medicinal applications, including as treatments for bacterial infection, Alzheimer's disease, and cancer. Two key 8HQs, CQ (5-chloro-7-iodo-8-hydroxyquinoline) and PBT2 (2-(dimethylamino)methyl-5,7-dichloro-8-hydroxyquinoline), have drawn considerable interest and have been the focus of many studies investigating their in vivo properties. These drugs have been described as copper and zinc ionophores because they do not cause metal depletion, as would be expected for a chelation mechanism, but rather cellular accumulation of these ions. In studies of their anti-cancer properties, CQ has been proposed to elicit toxic intracellular copper accumulation and to trigger apoptotic cancer cell death through several possible pathways. In this study we used synchrotron X-ray fluorescence imaging, in combination with biochemical assays and light microscopy, to investigate 8HQ-induced alterations to metal ion homeostasis, as well as cytotoxicity and cell death. We used the bromine fluorescence from a bromine labelled CQ congener (5,7-dibromo-8-hydroxyquinoline; B2Q) to trace the intracellular localization of B2Q following treatment and found that B2Q crosses the cell membrane. We also found that 8HQ co-treatment with Cu(ii) results in significantly increased intracellular copper and significant cytotoxicity compared with 8HQ treatments alone. PBT2 was found to be more cytotoxic, but a weaker Cu(ii) ionophore than other 8HQs. Moreover, treatment of cells with copper in the presence of CQ or B2Q resulted in copper accumulation in the nuclei, while PBT2-guided copper was distributed near to the cell membrane. These results suggest that PBT2 may be acting through a different mechanism than that of other 8HQs to cause the observed cytotoxicity.
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Affiliation(s)
- Kelly L Summers
- Molecular and Environmental Sciences Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.
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6
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Summers KL, Roseman GP, Sopasis GJ, Millhauser GL, Harris HH, Pickering IJ, George GN. Copper(II) Binding to PBT2 Differs from That of Other 8-Hydroxyquinoline Chelators: Implications for the Treatment of Neurodegenerative Protein Misfolding Diseases. Inorg Chem 2020; 59:17519-17534. [PMID: 33226796 PMCID: PMC7927943 DOI: 10.1021/acs.inorgchem.0c02754] [Citation(s) in RCA: 8] [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] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PBT2 (5,7-dichloro-2-[(dimethylamino)methyl]-8-hydroxyquinoline) is a small Cu(II)-binding drug that has been investigated in the treatment of neurodegenerative diseases, namely, Alzheimer's disease (AD). PBT2 is thought to be highly effective at crossing the blood-brain barrier and has been proposed to exert anti-Alzheimer's effects through the modulation of metal ion concentrations in the brain, specifically the sequestration of Cu(II) from amyloid plaques. However, despite promising initial results in animal models and in clinical trials where PBT2 was shown to improve cognitive function, larger-scale clinical trials did not find PBT2 to have a significant effect on the amyloid plaque burden compared with controls. We propose that the results of these clinical trials likely point to a more complex mechanism of action for PBT2 other than simple Cu(II) sequestration. To this end, herein we have investigated the solution chemistry of Cu(II) coordination by PBT2 primarily using X-ray absorption spectroscopy (XAS), high-energy-resolution fluorescence-detected XAS, and electron paramagnetic resonance. We propose that a novel bis-PBT2 Cu(II) complex with asymmetric coordination may coexist in solution with a symmetric four-coordinate Cu(II)-bis-PBT2 complex distorted from coplanarity. Additionally, PBT2 is a more flexible ligand than other 8HQs because it can act as both a bidentate and a tridentate ligand as well as coordinate Cu(II) in both 1:1 and 2:1 PBT2/Cu(II) complexes.
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Affiliation(s)
- Kelly L Summers
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham P Roseman
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, United States
| | - George J Sopasis
- Department of Chemistry, University of Adelaide, South Australia 5005, Australia
| | - Glenn L Millhauser
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, United States
| | - Hugh H Harris
- Department of Chemistry, University of Adelaide, South Australia 5005, Australia
| | - Ingrid J Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Graham N George
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
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Summers KL, Sarbisheh EK, Zimmerling A, Cotelesage JJH, Pickering IJ, George GN, Price EW. Structural Characterization of the Solution Chemistry of Zirconium(IV) Desferrioxamine: A Coordination Sphere Completed by Hydroxides. Inorg Chem 2020; 59:17443-17452. [PMID: 33183002 DOI: 10.1021/acs.inorgchem.0c02725] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Positron emission tomography (PET) using radiolabeled, monoclonal antibodies has become an effective, noninvasive method for tumor detection and is a critical component of targeted radionuclide therapy. Metal ion chelator and bacterial siderophore desferrioxamine (DFO) is the gold standard compound for incorporation of zirconium-89 in radiotracers for PET imaging because it is thought to form a stable chelate with [89Zr]Zr4+. However, DFO may not bind zirconium-89 tightly in vivo, with free zirconium-89 reportedly liberated into the bones of experimental mouse models. Although high bone uptake has not been observed to date in humans, this potential instability has been proposed to be related to the unsaturated coordination sphere of [89Zr]Zr-DFO, which is thought to consist of the 3 hydroxamate groups of DFO and 1 or 2 water molecules. In this study, we have used a combination of X-ray absorption spectroscopy and density functional theory (DFT) geometry optimization calculations to further probe the coordination chemistry of this complex in solution. We find the extended X-ray absorption fine structure (EXAFS) curve fitting of an aqueous solution of Zr(IV)-DFO to be consistent with an 8-coordinate Zr with oxygen ligands. DFT calculations suggest that the most energetically favorable Zr(IV) coordination environment in DFO likely consists of the 3 hydroxamate ligands from DFO, each with bidentate coordination, and 2 hydroxide ligands. Further EXAFS curve fitting provides additional support for this model. Therefore, we propose that the coordination sphere of Zr(IV)-DFO is most likely completed by 2 hydroxide ligands rather than 2 water molecules, forming Zr(DFO)(OH)2.
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Affiliation(s)
- Kelly L Summers
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, Canada S7N 5E2
| | - Elaheh Khozeimeh Sarbisheh
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9
| | - Amanda Zimmerling
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9
| | - Julien J H Cotelesage
- Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, Canada S7N 5E2
| | - Ingrid J Pickering
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, Canada S7N 5E2
| | - Graham N George
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9.,Molecular and Environmental Science Group, Department of Geological Sciences, College of Arts and Science, University of Saskatchewan, Saskatoon, Canada S7N 5E2
| | - Eric W Price
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK Canada S7N 5C9
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Summers KL, Pushie MJ, Sopasis GJ, James AK, Dolgova NV, Sokaras D, Kroll T, Harris HH, Pickering IJ, George GN. Solution Chemistry of Copper(II) Binding to Substituted 8-Hydroxyquinolines. Inorg Chem 2020; 59:13858-13874. [PMID: 32936627 DOI: 10.1021/acs.inorgchem.0c01356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
8-Hydroxyquinolines (8HQs) are a family of lipophilic metal ion chelators that have been used in a range of analytical and pharmaceutical applications over the last 100 years. More recently, CQ (clioquinol; 5-chloro-7-iodo-8-hydroxyquinoline) and PBT2 (5,7-dichloro-2-[(dimethylamino)methyl]-8-hydroxyquinoline) have undergone clinical trials for the treatment of Alzheimer's disease and Huntington's disease. Because CQ and PBT2 appear to redistribute metals into cells, these compounds have been redefined as copper and zinc ionophores. Despite the attention surrounding the clinical trials and the clear link between 8HQs and metals, the fundamental solution chemistry of how these compounds bind divalent metals such as copper and zinc, as well as their mechanism(s) of action in mammalian systems, remains poorly understood. In this study, we used a combination of X-ray absorption spectroscopy (XAS), high-energy resolution fluorescence detected (HERFD) XAS, electron paramagnetic resonance (EPR), and UV-visible absorption spectroscopies to investigate the aqueous solution chemistry of a range of 8HQ derivatives. To circumvent the known solubility issues with 8HQ compounds and their complexes with Cu(II), and to avoid the use of abiological organic solvents, we have devised a surfactant buffer system to investigate these Cu(II) complexes in aqueous solution. Our study comprises the first comprehensive investigation of the Cu(II) complexes formed with many 8HQs of interest in aqueous solution, and it provides the first structural information on some of these complexes. We find that halogen substitutions in 8HQ derivatives appear to have little effect on the Cu(II) coordination environment; 5,7-dihalogenated 8HQ conformers all have a pseudo square planar Cu(II) bound by two quinolin-8-olate anions, in agreement with previous studies. Conversely, substituents in the 2-position of the 8HQ moiety appear to cause significant distortions from the typical square-planar-like coordination of most Cu(II)-bis-8HQ complexes, such that the 8HQ moieties in the Cu(II)-bis-8HQ complex are rotated approximately 30-40° apart in a "propeller-like" arrangement.
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Affiliation(s)
- Kelly L Summers
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - M Jake Pushie
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - George J Sopasis
- Department of Chemistry, University of Adelaide, South Australia 5005, Australia
| | - Ashley K James
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Department of Anatomy and Cell Biology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada.,Toxicology Centre, University of Saskatchewan, 44 Campus Dr, Saskatoon, Saskatchewan S7N 5B3, Canada
| | - Natalia V Dolgova
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Hugh H Harris
- Department of Chemistry, University of Adelaide, South Australia 5005, Australia
| | - Ingrid J Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada.,Toxicology Centre, University of Saskatchewan, 44 Campus Dr, Saskatoon, Saskatchewan S7N 5B3, Canada
| | - Graham N George
- Molecular and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.,Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada.,Department of Anatomy and Cell Biology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
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9
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Kaur G, Javed W, Ponomarenko O, Shekh K, Swanlund DP, Zhou JR, Summers KL, Casini A, Wenzel MN, Casey JR, Cordat E, Pickering IJ, George GN, Leslie EM. Human red blood cell uptake and sequestration of arsenite and selenite: Evidence of seleno-bis(S-glutathionyl) arsinium ion formation in human cells. Biochem Pharmacol 2020; 180:114141. [PMID: 32652143 DOI: 10.1016/j.bcp.2020.114141] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 03/31/2020] [Revised: 06/24/2020] [Accepted: 07/06/2020] [Indexed: 01/07/2023]
Abstract
Over 200 million people worldwide are exposed to the human carcinogen, arsenic, in contaminated drinking water. In laboratory animals, arsenic and the essential trace element, selenium, can undergo mutual detoxification through the formation of the seleno-bis(S-glutathionyl) arsinium ion [(GS)2AsSe]-, which undergoes biliary and fecal elimination. [(GS)2AsSe]-, formed in animal red blood cells (RBCs), sequesters arsenic and selenium, and slows the distribution of both compounds to peripheral tissues susceptible to toxic effects. In human RBCs, the influence of arsenic on selenium accumulation, and vice versa, is largely unknown. The study aims were to characterize arsenite (AsIII) and selenite (SeIV) uptake by human RBCs, to determine if SeIV and AsIII increase the respective accumulation of the other in human RBCs, and ultimately to determine if this occurs through the formation and sequestration of [(GS)2AsSe]-. 75SeIV accumulation was temperature and Cl--dependent, inhibited by 4,4'-diisothiocyanatodihydrostilbene-2,2'-disulfonic acid (H2DIDS) (IC50 1 ± 0.2 µM), and approached saturation at 30 µM, suggesting uptake is mediated by the erythrocyte anion-exchanger 1 (AE1 or Band 3, gene SLC4A1). HEK293 cells overexpressing AE1 showed concentration-dependent 75SeIV uptake. 73AsIII uptake by human RBCs was temperature-dependent, partly reduced by aquaglyceroporin 3 inhibitors, and not saturated. AsIII increased 75SeIV accumulation (in the presence of albumin) and SeIV increased 73AsIII accumulation in human RBCs. Near-edge X-ray absorption spectroscopy revealed the formation of [(GS)2AsSe]- in human RBCs exposed to both AsIII and SeIV. The sequestration of [(GS)2AsSe]- in human RBCs potentially slows arsenic distribution to susceptible tissues and could reduce arsenic-induced disease.
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Affiliation(s)
- Gurnit Kaur
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Canada; Membrane Protein Disease Research Group, University of Alberta, Canada
| | - Warda Javed
- Membrane Protein Disease Research Group, University of Alberta, Canada; Department of Physiology, University of Alberta, Canada
| | - Olena Ponomarenko
- Department of Geological Sciences, University of Saskatchewan, Canada
| | - Kamran Shekh
- Membrane Protein Disease Research Group, University of Alberta, Canada; Department of Physiology, University of Alberta, Canada
| | - Diane P Swanlund
- Membrane Protein Disease Research Group, University of Alberta, Canada; Department of Physiology, University of Alberta, Canada
| | - Janet R Zhou
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Canada; Membrane Protein Disease Research Group, University of Alberta, Canada
| | - Kelly L Summers
- Department of Geological Sciences, University of Saskatchewan, Canada; Department of Chemistry, University of Saskatchewan, Canada
| | - Angela Casini
- School of Chemistry, Cardiff University, UK; Department of Chemistry, Technical University of Munich, Germany
| | | | - Joseph R Casey
- Membrane Protein Disease Research Group, University of Alberta, Canada; Department of Physiology, University of Alberta, Canada; Department of Biochemistry, University of Alberta, Canada
| | - Emmanuelle Cordat
- Membrane Protein Disease Research Group, University of Alberta, Canada; Department of Physiology, University of Alberta, Canada
| | - Ingrid J Pickering
- Department of Geological Sciences, University of Saskatchewan, Canada; Department of Chemistry, University of Saskatchewan, Canada
| | - Graham N George
- Department of Geological Sciences, University of Saskatchewan, Canada; Department of Chemistry, University of Saskatchewan, Canada
| | - Elaine M Leslie
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Canada; Membrane Protein Disease Research Group, University of Alberta, Canada; Department of Physiology, University of Alberta, Canada.
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10
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Kaur G, Ponomarenko O, Zhou JR, Swanlund DP, Summers KL, Dolgova NV, Antipova O, Pickering IJ, George GN, Leslie EM. Studies of selenium and arsenic mutual protection in human HepG2 cells. Chem Biol Interact 2020; 327:109162. [PMID: 32524993 DOI: 10.1016/j.cbi.2020.109162] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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: 04/09/2020] [Revised: 05/25/2020] [Accepted: 06/02/2020] [Indexed: 10/24/2022]
Abstract
Hundreds of millions of people worldwide are exposed to unacceptable levels of carcinogenic inorganic arsenic. Animal models have shown that selenium and arsenic are mutually protective through the formation and elimination of the seleno-bis(S-glutathionyl) arsinium ion [(GS)2AsSe]-. Consistent with this, human selenium deficiency in arsenic-endemic regions is associated with arsenic-induced disease, leading to the initiation of human selenium supplementation trials. In contrast to the protective effect observed in vivo, in vitro studies have suggested that selenite increases arsenite cellular retention and toxicity. This difference might be explained by the rapid conversion of selenite to selenide in vivo. In the current study, selenite did not protect the human hepatoma (HepG2) cell line against the toxicity of arsenite at equimolar concentrations, however selenide increased the IC50 by 2.3-fold. Cytotoxicity assays of arsenite + selenite and arsenite + selenide at different molar ratios revealed higher overall mutual antagonism of arsenite + selenide toxicity than arsenite + selenite. Despite this protective effect, in comparison to 75Se-selenite, HepG2 cells in suspension were at least 3-fold more efficient at accumulating selenium from reduced 75Se-selenide, and its accumulation was further increased by arsenite. X-ray fluorescence imaging of HepG2 cells also showed that arsenic accumulation, in the presence of selenide, was higher than in the presence of selenite. These results are consistent with a greater intracellular availability of selenide relative to selenite for protection against arsenite, and the formation and retention of a less toxic product, possibly [(GS)2AsSe]-.
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Affiliation(s)
- Gurnit Kaur
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada; Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Olena Ponomarenko
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Janet R Zhou
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada; Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Diane P Swanlund
- Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada; Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Kelly L Summers
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Natalia V Dolgova
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Olga Antipova
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, USA
| | - Ingrid J Pickering
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Graham N George
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Elaine M Leslie
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada; Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada; Department of Physiology, University of Alberta, Edmonton, Alberta, Canada.
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11
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Dolgova NV, Nehzati S, MacDonald TC, Summers KL, Crawford AM, Krone PH, George GN, Pickering IJ. Disruption of selenium transport and function is a major contributor to mercury toxicity in zebrafish larvae. Metallomics 2020; 11:621-631. [PMID: 30688331 DOI: 10.1039/c8mt00315g] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Mercury is one of the most toxic elements threatening the biosphere, with levels steadily rising due to both natural and human activities. Selenium is an essential micronutrient, required for normal development and functioning of many organisms. While selenium is known to counteract mercury's toxicity under some conditions, to date information about the mercury-selenium relationship is fragmented and often controversial. As part of a systematic study of mercury and selenium interactions, zebrafish (Danio rerio) larvae (a model verterbrate) were exposed to methylmercury chloride or mercuric chloride. The influence of pre- and post-treatment of selenomethionine on the level and distribution of mercury and selenium in the brain and eye sections, as well as on toxicity, were examined. Selenomethionine treatment decreased the amount of maternally transfered mercury in the larval brain. Selenomethionine treatment prior to exposure to mercuric chloride increased both mercury and selenium levels in the brain but decreased their toxic effects. Conversely, methylmercury levels were not changed as a result of selenium pre-treatment, while toxicity was increased. Strikingly, both forms of mercury severely disrupted selenium metabolism, not only by depleting selenium levels due to formation of Hg-Se complexes, but also by blocking selenium transport into and out of tissues, suggesting that restoring normal selenium levels by treating the organism with selenium after mercury exposure may not be possible. Disruption of selenium metabolism by mercury may lead to disruption in function of selenoproteins. Indeed, the production of thyroid hormones by selenoprotein deiodinases was found to be severely impaired as a result of mercury exposure, with selenomethionine not always being a suitable source of selenium to restore thyroid hormone levels.
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Affiliation(s)
- Natalia V Dolgova
- Molecular and Environment Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.
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12
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Leslie EM, Kaur G, Javed W, Ponomarenko O, Swanlund DP, Hu M, Summers KL, Casini A, Wenzel M, Casey JR, Cordat E, Pickering IJ, George GN. Human Red Blood Cell Uptake and Sequestration of Arsenite and Selenite: Evidence for the Formation of a Protective Glutathione Conjugate. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.06204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Ramsay TG, Kahl S, Long JA, Summers KL. Peripheral histamine and neonatal growth performance in swine. Domest Anim Endocrinol 2020; 70:106370. [PMID: 31585314 DOI: 10.1016/j.domaniend.2019.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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] [Received: 09/28/2018] [Revised: 05/23/2019] [Accepted: 06/10/2019] [Indexed: 01/01/2023]
Abstract
Identification of plasma and/or serum markers at birth that will predict animal performance may be useful for identifying animals susceptible to poor growth. Metabolomic analysis of plasma from newborn swine was used to identified potential metabolite differences between 8 pairs of littermates with similar birth weights but whose ADG differed by >50 g/d so that, at weaning (21 d), littermates differed in BW by 1.62 kg (P < 0.01). Plasma analysis failed to identify metabolic pathways impacted by growth, most likely because of the small sample population. Interestingly, despite comparative analysis of 576 metabolites between these slow-growing and normal-growing littermates, the relative abundance of only 36 metabolites differed between the pairs. Most of these metabolites could be eliminated as potential markers because of the difficulty with the extraction and rapid measurement of their plasma/serum concentrations. Histamine differed from most of these potential metabolite markers in that commercial sandwich ELISAs are readily available. Using an ELISA, we verified the metabolomic data, demonstrating that plasma histamine concentrations were 150% higher in slow-growing than normal growing littermates of similar birth weight (P < 0.05). Subsequently, a separate data set was obtained using swine from a different geographical location and genetic background and also showed that elevated histamine (ng/mL) at birth is associated with increased preweaning growth rate (P = 0.009, r = 0.306, n = 9 litters). Together, the data indicate that perinatal histamine concentrations may serve as a tool to identify potentially slower growing pigs and as a serum biomarker for predicting litter growth rate.
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Affiliation(s)
- T G Ramsay
- U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD 20705, USA.
| | - S Kahl
- U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD 20705, USA
| | - J A Long
- U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD 20705, USA
| | - K L Summers
- U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD 20705, USA
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14
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Rudak PT, Gangireddy R, Choi J, Burhan AM, Summers KL, Jackson DN, Inoue W, Haeryfar SMM. Stress-elicited glucocorticoid receptor signaling upregulates TIGIT in innate-like invariant T lymphocytes. Brain Behav Immun 2019; 80:793-804. [PMID: 31108170 DOI: 10.1016/j.bbi.2019.05.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [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: 10/24/2018] [Revised: 03/22/2019] [Accepted: 05/16/2019] [Indexed: 12/17/2022] Open
Abstract
Stress is known to impede certain host defense mechanisms, including those governed by conventional T lymphocytes. However, whether innate-like T lymphocytes, such as invariant natural killer T (iNKT) and mucosa-associated invariant T (MAIT) cells, are impacted by stress is unclear. Herein, we report that prolonged psychological stress caused by physical confinement results in robust upregulation of T cell immunoreceptor with immunoglobulin and ITIM domains (TIGIT), an immune checkpoint receptor that controls antitumor and antiviral immune responses. Elevated TIGIT expression was found not only on NK and conventional T cells, but also on iNKT and MAIT cells. Stress-provoked TIGIT upregulation was reversed through treatment with the glucocorticoid receptor (GR) antagonist RU486, but not with 6-hydroxydopamine that induces chemical sympathectomy. A Cre/Lox gene targeting model in which GR was ablated in cells expressing Lck under its proximal promoter revealed that TIGIT upregulation in stressed animals stems from direct GR signaling in T and iNKT cells. In fact, long-term oral administration of exogenous corticosterone (CS) to wild-type C57BL/6 (B6) mice was sufficient to increase TIGIT expression levels on T and iNKT cells. In vitro treatment with CS also potently and selectively upregulated TIGIT, but not CTLA-4 or LAG-3, on mouse iNKT and MAIT hybridomas. These results were recapitulated using primary hepatic iNKT and MAIT cells from wild-type B6 and B6.MAITCAST mice, respectively. Subjecting B6.MAITCAST mice to physical restraint also raised the frequency of TIGIT+ cells among hepatic MAIT cells in a GR-dependent manner. Finally, we found that TIGIT is similarly upregulated in a chronic variable stress model in which animals are exposed to unpredictable heterotypic stressors without developing habituation. Taken together, our findings link, for the first time to our knowledge, GR signaling to TIGIT expression. We propose that glucocorticoid hormones dampen immune responses, in part, by enhancing TIGIT expression across multiple critical subsets of effector lymphocytes, including innate-like T cells. Therefore, TIGIT may constitute an attractive target in immune-enhancing interventions for sustained physiological stress.
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Affiliation(s)
- Patrick T Rudak
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada
| | - Rakshith Gangireddy
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada
| | - Joshua Choi
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada
| | - Amer M Burhan
- Department of Psychiatry, Western University, London, Ontario, Canada
| | - Kelly L Summers
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada
| | - Dwayne N Jackson
- Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Wataru Inoue
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada
| | - S M Mansour Haeryfar
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada; Department of Medicine, Division of Clinical Immunology and Allergy, Western University, London, Ontario, Canada; Department of Surgery, Division of General Surgery, Western University, London, Ontario, Canada.
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15
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Lacasse MJ, Summers KL, Khorasani-Motlagh M, George GN, Zamble DB. Bimodal Nickel-Binding Site on Escherichia coli [NiFe]-Hydrogenase Metallochaperone HypA. Inorg Chem 2019; 58:13604-13618. [PMID: 31273981 DOI: 10.1021/acs.inorgchem.9b00897] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
[NiFe]-hydrogenase enzymes catalyze the reversible oxidation of hydrogen at a bimetallic cluster and are used by bacteria and archaea for anaerobic growth and pathogenesis. Maturation of the [NiFe]-hydrogenase requires several accessory proteins to assemble and insert the components of the active site. The penultimate maturation step is the delivery of nickel to a primed hydrogenase enzyme precursor protein, a process that is accomplished by two nickel metallochaperones, the accessory protein HypA and the GTPase HypB. Recent work demonstrated that nickel is rapidly transferred to HypA from GDP-loaded HypB within the context of a protein complex in a nickel selective and unidirectional process. To investigate the mechanism of metal transfer, we examined the allosteric effects of nucleotide cofactors and partner proteins on the nickel environments of HypA and HypB by using a combination of biochemical, microbiological, computational, and spectroscopic techniques. We observed that loading HypB with either GDP or a nonhydrolyzable GTP analogue resulted in a similar nickel environment. In addition, interaction with a mutant version of HypA with disrupted nickel binding, H2Q-HypA, does not induce substantial changes to the HypB G-domain nickel site. Instead, the results demonstrate that HypB modifies the acceptor site of HypA. Analysis of a peptide maquette derived from the N-terminus of HypA revealed that nickel is predominately coordinated by atoms from the N-terminal Met-His motif. Furthermore, HypA is capable of two nickel-binding modes at the N-terminus, a HypB-induced mode and a binding mode that mirrors the peptide maquette. Collectively, these results reveal that HypB brings about changes in the nickel coordination of HypA, providing a mechanism for the HypB-dependent control of the acquisition and release of nickel by HypA.
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Affiliation(s)
- Michael J Lacasse
- Department of Chemistry , University of Toronto , Toronto , Ontario M5S 3H6 , Canada
| | - Kelly L Summers
- Department of Chemistry , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5C9 , Canada
| | | | - Graham N George
- Department of Geological Sciences , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Deborah B Zamble
- Department of Chemistry , University of Toronto , Toronto , Ontario M5S 3H6 , Canada.,Department of Biochemistry , University of Toronto , Toronto , Ontario M5S 1A8 , Canada
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16
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Singh B, Summers KL, Kerfoot SM. Novel regulatory Th17 cells and regulatory B cells in modulating autoimmune diseases. Cell Immunol 2019; 339:29-32. [DOI: 10.1016/j.cellimm.2018.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 09/15/2018] [Indexed: 02/08/2023]
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17
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Summers KL, Schilling KM, Roseman G, Markham KA, Dolgova NV, Kroll T, Sokaras D, Millhauser GL, Pickering IJ, George GN. X-ray Absorption Spectroscopy Investigations of Copper(II) Coordination in the Human Amyloid β Peptide. Inorg Chem 2019; 58:6294-6311. [PMID: 31013069 DOI: 10.1021/acs.inorgchem.9b00507] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Alzheimer's disease (AD) is the main cause of age-related dementia and currently affects approximately 5.7 million Americans. Major brain changes associated with AD pathology include accumulation of amyloid beta (Aβ) protein fragments and formation of extracellular amyloid plaques. Redox-active metals mediate oligomerization of Aβ, and the resultant metal-bound oligomers have been implicated in the putative formation of harmful, reactive species that could contribute to observed oxidative damage. In isolated plaque cores, Cu(II) is bound to Aβ via histidine residues. Despite numerous structural studies of Cu(II) binding to synthetic Aβ in vitro, there is still uncertainty surrounding Cu(II) coordination in Aβ. In this study, we used X-ray absorption spectroscopy (XAS) and high energy resolution fluorescence detected (HERFD) XAS to investigate Cu(II) coordination in Aβ(1-42) under various solution conditions. We found that the average coordination environment in Cu(II)Aβ(1-42) is sensitive to X-ray photoreduction, changes in buffer composition, peptide concentration, and solution pH. Fitting of the extended X-ray absorption fine structure (EXAFS) suggests Cu(II) is bound in a mixture of coordination environments in monomeric Aβ(1-42) under all conditions studied. However, it was evident that on average only a single histidine residue coordinates Cu(II) in monomeric Aβ(1-42) at pH 6.1, in addition to 3 other oxygen or nitrogen ligands. Cu(II) coordination in Aβ(1-42) at pH 7.4 is similarly 4-coordinate with oxygen and nitrogen ligands, although an average of 2 histidine residues appear to coordinate at this pH. At pH 9.0, the average Cu(II) coordination environment in Aβ(1-42) appears to be 5-coordinate with oxygen and nitrogen ligands, including two histidine residues.
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Affiliation(s)
- Kelly L Summers
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , 114 Science Place , Saskatoon , Saskatchewan S7N 5E2 , Canada.,Department of Chemistry , University of Saskatchewan , 110 Science Place , Saskatoon , Saskatchewan S7N 5C9 , Canada
| | - Kevin M Schilling
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
| | - Graham Roseman
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
| | - Kate A Markham
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
| | - Natalia V Dolgova
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , 114 Science Place , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 , United States
| | - Glenn L Millhauser
- Department of Chemistry and Biochemistry , University of California , Santa Cruz , California 95064 , United States
| | - Ingrid J Pickering
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , 114 Science Place , Saskatoon , Saskatchewan S7N 5E2 , Canada.,Department of Chemistry , University of Saskatchewan , 110 Science Place , Saskatoon , Saskatchewan S7N 5C9 , Canada
| | - Graham N George
- Molecular and Environmental Sciences Group, Department of Geological Sciences , University of Saskatchewan , 114 Science Place , Saskatoon , Saskatchewan S7N 5E2 , Canada.,Department of Chemistry , University of Saskatchewan , 110 Science Place , Saskatoon , Saskatchewan S7N 5C9 , Canada
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18
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Summers KL. A Structural Chemistry Perspective on the Antimalarial Properties of Thiosemicarbazone Metal Complexes. Mini Rev Med Chem 2019; 19:569-590. [DOI: 10.2174/1389557518666181015152657] [Citation(s) in RCA: 20] [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] [Received: 11/26/2017] [Revised: 06/26/2018] [Accepted: 09/30/2018] [Indexed: 01/14/2023]
Abstract
Malaria is a potentially life-threatening disease, affecting approx. 214 million people worldwide. Malaria is caused by a protozoan, Plasmodium falciparum, which is transmitted through the Anopheles mosquito. Malaria treatment is becoming more challenging due to rising resistance against the antimalarial drug, chloroquine. Novel compounds that target aspects of parasite development are being explored in attempts to overcome this wide-spread problem. Anti-malarial drugs target specific aspects of parasite growth and development within the human host. One of the most effective targets is the inhibition of hematin formation, either through inhibition of cysteine proteases or through iron chelation. Metal-thiosemicarbazone (TSC) complexes have been tested for antimalarial efficacy against drug-sensitive and drug-resistant strains of P. falciparum. An array of TSC complexes with numerous transition metals, including ruthenium, palladium, and gold has displayed antiplasmodial activity. Au(I)- and Pd(II)-TSC complexes displayed the greatest potency; 4-amino-7-chloroquine moieties were also found to improve antiplasmodial activity of TSCs. Although promising metal-TSC drug candidates have been tested against laboratory strains of P. falciparum, problems arise when attempting to compare between studies. Future work should strive to completely characterize synthesized metal-TSC structures and assess antiplasmodial potency against several drug-sensitive and drugresistant strains. Future studies need to precisely determine IC50 values for antimalarial drugs, chloroquine and ferroquine, to establish accurate standard values. This will make future comparisons across studies more feasible and potentially help reveal structure-function relationships. Investigations that attempt to link drug structures or properties to antiplasmodial mechanism(s) of action will aid in the design of antimalarial drugs that may combat rising drug resistance.
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Affiliation(s)
- Kelly L. Summers
- Department of Chemistry, College of Arts and Science, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada
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19
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Summers KL, Fimognari N, Hollings A, Kiernan M, Lam V, Tidy RJ, Paterson D, Tobin MJ, Takechi R, George GN, Pickering IJ, Mamo JC, Harris HH, Hackett MJ. A Multimodal Spectroscopic Imaging Method To Characterize the Metal and Macromolecular Content of Proteinaceous Aggregates (“Amyloid Plaques”). Biochemistry 2017; 56:4107-4116. [DOI: 10.1021/acs.biochem.7b00262] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Kelly L. Summers
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Nicholas Fimognari
- School
of Biomedical Sciences, Curtin University, Bentley, Western Australia 6102, Australia
- Curtin
Health Innovation Research Institute, Curtin University, Bentley, Western Australia 6102, Australia
| | - Ashley Hollings
- Curtin
Health Innovation Research Institute, Curtin University, Bentley, Western Australia 6102, Australia
- Department
of Chemistry, Curtin University, GPO Box U1987, Bentley, Western Australia 6845, Australia
- Curtin Institute
of Functional Molecules and Interfaces, Curtin University, Bentley, Western Australia 6845, Australia
| | - Mitchell Kiernan
- Curtin
Health Innovation Research Institute, Curtin University, Bentley, Western Australia 6102, Australia
- Department
of Chemistry, Curtin University, GPO Box U1987, Bentley, Western Australia 6845, Australia
- Curtin Institute
of Functional Molecules and Interfaces, Curtin University, Bentley, Western Australia 6845, Australia
| | - Virginie Lam
- Curtin
Health Innovation Research Institute, Curtin University, Bentley, Western Australia 6102, Australia
- School of
Public Health, Curtin University, Bentley, Western Australia 6102, Australia
| | - Rebecca J. Tidy
- Curtin
Health Innovation Research Institute, Curtin University, Bentley, Western Australia 6102, Australia
- Department
of Chemistry, Curtin University, GPO Box U1987, Bentley, Western Australia 6845, Australia
- Curtin Institute
of Functional Molecules and Interfaces, Curtin University, Bentley, Western Australia 6845, Australia
| | - David Paterson
- Australian Synchrotron, Clayton, Victoria 3068, Australia
| | - Mark J. Tobin
- Australian Synchrotron, Clayton, Victoria 3068, Australia
| | - Ryu Takechi
- Curtin
Health Innovation Research Institute, Curtin University, Bentley, Western Australia 6102, Australia
- School of
Public Health, Curtin University, Bentley, Western Australia 6102, Australia
| | - Graham N. George
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - Ingrid J. Pickering
- Molecular
and Environmental Sciences Group, Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada
- Department
of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada
| | - John C. Mamo
- Curtin
Health Innovation Research Institute, Curtin University, Bentley, Western Australia 6102, Australia
- School of
Public Health, Curtin University, Bentley, Western Australia 6102, Australia
| | - Hugh H. Harris
- Department
of Chemistry, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Mark J. Hackett
- Curtin
Health Innovation Research Institute, Curtin University, Bentley, Western Australia 6102, Australia
- Department
of Chemistry, Curtin University, GPO Box U1987, Bentley, Western Australia 6845, Australia
- Curtin Institute
of Functional Molecules and Interfaces, Curtin University, Bentley, Western Australia 6845, Australia
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20
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Dolgova NV, Yu C, Cvitkovic JP, Hodak M, Nienaber KH, Summers KL, Cotelesage JJH, Bernholc J, Kaminski GA, Pickering IJ, George GN, Dmitriev OY. Binding of Copper and Cisplatin to Atox1 Is Mediated by Glutathione through the Formation of Metal-Sulfur Clusters. Biochemistry 2017; 56:3129-3141. [PMID: 28549213 DOI: 10.1021/acs.biochem.7b00293] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Copper is an essential nutrient required for many biological processes involved in primary metabolism, but free copper is toxic due to its ability to catalyze formation of free radicals. To prevent toxic effects, in the cell copper is bound to proteins and low molecular weight compounds, such as glutathione, at all times. The widely used chemotherapy agent cisplatin is known to bind to copper-transporting proteins, including copper chaperone Atox1. Cisplatin interactions with Atox1 and other copper transporters are linked to cancer resistance to platinum-based chemotherapy. Here we analyze the binding of copper and cisplatin to Atox1 in the presence of glutathione under redox conditions that mimic intracellular environment. We show that copper(I) and glutathione form large polymers with a molecular mass of approximately 8 kDa, which can transfer copper to Atox1. Cisplatin also can form polymers with glutathione, albeit at a slower rate. Analysis of simultaneous binding of copper and cisplatin to Atox1 under physiological conditions shows that both metals are bound to the protein through copper-sulfur-platinum bridges.
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Affiliation(s)
- Natalia V Dolgova
- Department of Biochemistry, University of Saskatchewan , Saskatoon, Saskatchewan, Canada , S7N 5E5.,Department of Geological Sciences, University of Saskatchewan , Saskatoon, Saskatchewan, Canada , S7N 5E2
| | - Corey Yu
- Department of Biochemistry, University of Saskatchewan , Saskatoon, Saskatchewan, Canada , S7N 5E5
| | - John P Cvitkovic
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States
| | - Miroslav Hodak
- Department of Physics, North Carolina State University , Raleigh, North Carolina 27695-7518, United States
| | - Kurt H Nienaber
- Department of Geological Sciences, University of Saskatchewan , Saskatoon, Saskatchewan, Canada , S7N 5E2
| | - Kelly L Summers
- Department of Chemistry, University of Saskatchewan , Saskatoon, Saskatchewan Canada , S7N 5C9
| | - Julien J H Cotelesage
- Department of Geological Sciences, University of Saskatchewan , Saskatoon, Saskatchewan, Canada , S7N 5E2
| | - Jerzy Bernholc
- Department of Physics, North Carolina State University , Raleigh, North Carolina 27695-7518, United States
| | - George A Kaminski
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States
| | - Ingrid J Pickering
- Department of Geological Sciences, University of Saskatchewan , Saskatoon, Saskatchewan, Canada , S7N 5E2.,Department of Chemistry, University of Saskatchewan , Saskatoon, Saskatchewan Canada , S7N 5C9
| | - Graham N George
- Department of Geological Sciences, University of Saskatchewan , Saskatoon, Saskatchewan, Canada , S7N 5E2.,Department of Chemistry, University of Saskatchewan , Saskatoon, Saskatchewan Canada , S7N 5C9
| | - Oleg Y Dmitriev
- Department of Biochemistry, University of Saskatchewan , Saskatoon, Saskatchewan, Canada , S7N 5E5
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21
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Kreuzer D, Nikoopour E, Au BCY, Krougly O, Lee-Chan E, Summers KL, Haeryfar SMM, Singh B. Reduced interferon-α production by dendritic cells in type 1 diabetes does not impair immunity to influenza virus. Clin Exp Immunol 2015; 179:245-55. [PMID: 25286929 DOI: 10.1111/cei.12462] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2014] [Indexed: 12/30/2022] Open
Abstract
The increased risk and persistence of infections in diabetic condition is probably associated with defects in the cellular immune responses. We have previously shown a decrease in the production of interferon (IFN)-α by dendritic cells (DCs) in diabetic subjects. The basal level of IFN-α in splenic plasmacytoid DCs (pDCs) is also lower in non-obese diabetic (NOD) mice compared to prediabetic mice. The objective of this study was to analyse the ability of diabetic mice to mobilize innate and CD8(+) T cell-mediated immune response to influenza A virus (IAV) with the live influenza A/Puerto Rico/8/1934 H1N1 (PR8) strain or with its immunodominant CD8(+) T cell epitopes. We found that following immunization with IAV, the level of IFN-α in diabetic mice was increased to the level in prediabetic mice. Immunization of NOD mice with the immunodominant IAV PR8 peptide induced clonal expansion of IFN-γ-producing CD8(+) T cells similar to the response observed in prediabetic mice. Thus, diabetic and prediabetic NOD mice have a similar capacity for IFN-α and IFN-γ production by pDCs and CD8(+) T cells, respectively. Therefore, the DC-related immune defect in diabetic NOD mice does not impair their capacity to develop an effective immune response to IAV. Our results suggest that reduced IFN-α production by diabetic human and mouse DCs is not an impediment to an effective immunity to IAV in type 1 diabetic subjects vaccinated with live attenuated influenza vaccine.
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Affiliation(s)
- D Kreuzer
- Centre for Human Immunology, Department of Microbiology and Immunology and Robarts Research Institute, University of Western Ontario, London, ON, Canada
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22
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Pope J, Walker KM, de Leon F, Vanderhoek L, Seney S, Summers KL. Correlations between changes in cytokines and clinical outcomes for early phase (proof of concept) trials in active diffuse systemic sclerosis using data from an imatinib study. Rheumatology (Oxford) 2014; 53:1830-4. [PMID: 24850877 DOI: 10.1093/rheumatology/keu216] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE Data from a small study testing imatinib to treat SSc were used to determine if cytokine changes were related to differences in clinical parameters to model future early phase trials pairing cytokine changes and clinical parameters. METHODS Plasma and punch skin biopsy specimens collected at baseline and 6 months were analysed for levels of 26 fibrotic and inflammatory cytokines using multiplexed immunoassays and ELISA. Seven of nine patients on active treatment had paired data. Biopsies were biopulverized and standardized to protein levels in the tissue homogenate. Plasma was frozen at -80°C and analysed using multiplexed immunoassays or ELISAs standardized to CRP. Correlations between fold changes in cytokines and differences in clinical parameters (skin score, physician and patient global assessments and HAQ) were performed. P < 0.01 was considered significant. RESULTS After 6 months of imatinib treatment, plasma levels of soluble vascular cell adhesion molecule 1 decreased significantly (P < 0.001), while tissue levels of soluble intercellular adhesion molecule 1 increased (P < 0.01). Some significant correlations between fold changes in certain plasma fibrotic and inflammatory cytokines and changes in clinical parameters after 6 months of treatment were found: patient global scores and IL-13 (r = 0.964, P < 0.0001); ESR and IL-12p70 (r = -0.903, P < 0.01); in tissue samples, patient global score and soluble E-selectin (r = 0.913, P < 0.01); and physician global score with sCD40L (r = -0.883, P < 0.01). CONCLUSION Some serum and tissue cytokines may have a role in early phase clinical trials of SSc, correlating with changes in clinical parameters. Serum and tissue samples could be analysed in early phase trials to determine whether they support the clinical observations. TRIAL REGISTRATION http://clinicaltrials.gov/show/NCT01545427.
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Affiliation(s)
- Janet Pope
- Division of Rheumatology, Department of Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada, Medical School, Trinity College Dublin, Dublin, Ireland, Department of Mathematics/Statistics, McMaster University, Hamilton, Lawson Health Research Institute and Department of Microbiology & Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Kyle M Walker
- Division of Rheumatology, Department of Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada, Medical School, Trinity College Dublin, Dublin, Ireland, Department of Mathematics/Statistics, McMaster University, Hamilton, Lawson Health Research Institute and Department of Microbiology & Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Faye de Leon
- Division of Rheumatology, Department of Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada, Medical School, Trinity College Dublin, Dublin, Ireland, Department of Mathematics/Statistics, McMaster University, Hamilton, Lawson Health Research Institute and Department of Microbiology & Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Louise Vanderhoek
- Division of Rheumatology, Department of Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada, Medical School, Trinity College Dublin, Dublin, Ireland, Department of Mathematics/Statistics, McMaster University, Hamilton, Lawson Health Research Institute and Department of Microbiology & Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Shannon Seney
- Division of Rheumatology, Department of Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada, Medical School, Trinity College Dublin, Dublin, Ireland, Department of Mathematics/Statistics, McMaster University, Hamilton, Lawson Health Research Institute and Department of Microbiology & Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Kelly L Summers
- Division of Rheumatology, Department of Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada, Medical School, Trinity College Dublin, Dublin, Ireland, Department of Mathematics/Statistics, McMaster University, Hamilton, Lawson Health Research Institute and Department of Microbiology & Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada Division of Rheumatology, Department of Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada, Medical School, Trinity College Dublin, Dublin, Ireland, Department of Mathematics/Statistics, McMaster University, Hamilton, Lawson Health Research Institute and Department of Microbiology & Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
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23
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Chan CJ, Summers KL, Chan NG, Hardy DB, Richardson BS. Cytokines in umbilical cord blood and the impact of labor events in low-risk term pregnancies. Early Hum Dev 2013; 89:1005-10. [PMID: 24045131 DOI: 10.1016/j.earlhumdev.2013.08.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [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: 04/26/2013] [Revised: 08/16/2013] [Accepted: 08/22/2013] [Indexed: 11/15/2022]
Abstract
BACKGROUND Inflammatory mechanisms involved in the onset and progression of labor at term may affect the fetal compartment impacting neonatal outcomes. STUDY DESIGN Umbilical cord blood collected from umbilical cords after delivery of the fetus and again after delivery of the placenta in low-risk non-laboring and laboring patients was analyzed for blood gases/pH and multiple cytokines. RESULTS Umbilical cord levels of IL-6, IL-8 and IL-10 were increased 6, 2 and 1.5 fold, respectively, in laboring patients without placental inflammation, and for IL-6 and IL-8 a further 12 and 6 fold, respectively, in laboring patients showing histologic chorioamnionitis, but with no evident effect of nuchal cord with FHR decelerations, fetal acidemia, nor of labor duration. For laboring patients, umbilical vein levels of IL-10 and MIP-1α were increased compared to arterial levels indicating net flux from the placenta, while umbilical artery levels of IL-6 and IL-8 were increased compared to venous levels indicating net flux from fetal sources. Placental cord levels of IL-6, IL-10, MIP-1α and MIP-1β were also increased compared to respective umbilical cord levels, confirming placental release of these cytokines into cord blood after delivery of the fetus. CONCLUSION Labor in low-risk patients at term will result in increased cytokines in umbilical cord blood and moreso when associated with histologic chorioamnionitis with the potential to impact neonatal outcomes. IL-6 and IL-8 as the primary cytokines increased in cord blood may act synergistically in promoting the inflammatory response with labor, and are likely released from both placental and fetal tissues contributing to widespread distribution through the fetal circulation.
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Affiliation(s)
- Cynthia J Chan
- Department of Obstetrics and Gynecology, The Children's Health Research Institute, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
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24
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Summers KL, Sutherland DEK, Stillman MJ. Single-domain metallothioneins: evidence of the onset of clustered metal binding domains in Zn-rhMT 1a. Biochemistry 2013; 52:2461-71. [PMID: 23506369 DOI: 10.1021/bi400021b] [Citation(s) in RCA: 19] [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] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mammalian metallothioneins bind up to seven Zn(2+) ions in two distinct domains: an N-terminal β-domain that binds three Zn(2+) ions and a C-terminal α-domain that binds four Zn(2+) ions. Domain specificity has been invoked in the metalation mechanism with cluster formation and bridging of the 20 Cys residues taking place prior to saturation with seven Zn(2+) ions. We report a novel experiment that examines Zn(2+) metalation by exploiting the expected decrease in K(F) at the onset of clustering using electrospray ionization mass spectrometry (ESI-MS). During the titration with Zn(2+), the ESI-MS data show that several metalated species coexist until the fully saturated proteins are formed. The relative Zn binding affinities of the seven total sites in the α- and β-fragments were determined through direct competition for added Zn(2+). The K(F) values for each Zn(2+) are expected to decrease as a function of the remaining available sites and the onset of clustering. Analysis shows that Zn(2+) binds to β-rhMT with a greater affinity than α-rhMT. The incremental distribution of Zn(2+) between the competing fragments and apo-βα-rhMT (essentially three and four sites competing with seven sites) identifies the exact point at which clustering begins in the full protein. Analysis of the speciation data shows that Zn(5)-MT forms before clustering begins. This means that all 20 Cys residues of apo-βα-rhMT are bound terminally to Zn(2+) as [Zn(Cys)(4)](2-) units before clustering begins; there is no domain preference in this first metalation stage. Preferential binding of Zn(2+) to β- and α-rhMT at the point where βα-rhMT must form clusters is caused by a significant decrease in the affinity of βα-rhMT for further Zn(2+). The single-domain Zn(5)-rhMT, in which there are no exposed cysteine sulfurs, is a key component of the metalation pathway because the lower affinities of the two clustered Zn(2+) ions allow donation to apoenzymes.
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Affiliation(s)
- Kelly L Summers
- Department of Chemistry, The University of Western Ontario, London, Canada N6A 5B7
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25
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Irvine GW, Summers KL, Stillman MJ. Cysteine accessibility during As3+ metalation of the α- and β-domains of recombinant human MT1a. Biochem Biophys Res Commun 2013; 433:477-83. [PMID: 23523794 DOI: 10.1016/j.bbrc.2013.03.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 03/02/2013] [Indexed: 10/27/2022]
Abstract
Metallothionein is a ubiquitous metal binding protein that plays an important role in metal ion homeostasis and redox chemistry within cells. Mammalian metallothioneins bind a wide variety of metals including the metalloid As3+ in two domains (β and α) connected by a short linker sequence. Three As3+ bind in each domain for a total of 6 As3+ per protein. In recombinant human metallothionein (rh-MT1a) each As3+ binds three cysteine residues to form As3Cys9(CysSH)2-α-rhMT1a in the 11 Cys α-domain and As3Cys9-β-rhMT1a in the 9 Cys β-domain. This means that there should be 2 free cysteines in the α-domain but no free cysteines in the β-domain. By using benzoquinone, the number and relative accessibility of the free cysteinyl thiols during the metalation reactions were determined. The electrospray ionization mass spectrometry (ESI-MS) data confirmed that each As3+ binds using exactly 3 cysteine thiols and showed that there was a significant difference in the reactivity of the free cysteines during the metalation reaction. After a reaction with two molar equivalents of As3+ to form As2Cys6(CysSH)3-αβ-rhMT1a, the remaining 3 Cys in the 9 Cys β-domain were far less reactive than those in the α-domain. Molecular dynamics calculations for the metalation reactions with As3+ measured by ESI-MS allowed an interpretation of the mass spectral data in terms of the relative location of the cysteine thiols that were not involved in As3+ coordination. Together, these data provide insight into the selection of a specific cysteinyl thiol by the incoming metals during the stepwise metalation of metallothioneins.
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Affiliation(s)
- Gordon W Irvine
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
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26
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Sutherland DE, Summers KL, Stillman MJ. Modeling the Zn2+ and Cd2+ metalation mechanism in mammalian metallothionein 1a. Biochem Biophys Res Commun 2012; 426:601-7. [DOI: 10.1016/j.bbrc.2012.08.136] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 08/28/2012] [Indexed: 10/27/2022]
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27
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Sutherland DEK, Summers KL, Stillman MJ. Noncooperative Metalation of Metallothionein 1a and Its Isolated Domains with Zinc. Biochemistry 2012; 51:6690-700. [DOI: 10.1021/bi3004523] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | - Kelly L. Summers
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Martin J. Stillman
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
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28
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Summers KL, Mahrok AK, Dryden MDM, Stillman MJ. Structural properties of metal-free apometallothioneins. Biochem Biophys Res Commun 2012; 425:485-92. [PMID: 22877750 DOI: 10.1016/j.bbrc.2012.07.141] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 07/25/2012] [Indexed: 11/30/2022]
Abstract
The metalated forms of metallothionein are well studied (particularly Zn-MT, Cu-MT and Cd-MT), but almost nothing is known about the chemical and structural properties of apometallothioneins despite their importance in initial metalation and subsequent demetalation. Electrospray ionization mass spectrometry was used to provide a detailed view of the structural properties of the metal-free protein. Mass spectra of Zn(7)-MT and apo-MT at pH 7 exhibit the same charge state distribution, indicating that apo-MT is tightly folded like the metallated protein, whereas apo-MT at pH 3 exhibits a charge state spectrum associated with unfolding or denaturation. Benzoquinone was used to modify the cysteines in the β-MT (9 Bq), and α-MT (11 Bq) fragments, and the full βα-MT (20 Bq) protein. ESI-MS showed that the overall volume and, therefore, the extent of folding for the modified proteins is similar to that of Zn-MT. Molecular modeling using MM3-MD methods provided the volume of each modified protein. The volumes of the partially modified proteins follow the same trend as the charge states, showing that ESI-MS is an excellent method with which to follow small changes in protein folding as a function of applied chemical stress. The data suggest that the structure of apo-βα-MT is more organized than previously considered.
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Affiliation(s)
- Kelly L Summers
- Department of Biology, The University of Western Ontario, London, Ontario, Canada N6A 5B7
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29
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Summers KL, Singh B. Research Highlights: Highlights from the latest articles in immunotherapy. Immunotherapy 2012; 4:363-4. [DOI: 10.2217/imt.12.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Kelly L Summers
- Centre for Human Immunology, Department of Microbiology & Immunology, Lawson Health Research Institute and Robarts Research Institute, Western University, London, Ontario, N6A 5C1, Canada
| | - Bhagirath Singh
- Centre for Human Immunology, Department of Microbiology & Immunology, Lawson Health Research Institute and Robarts Research Institute, Western University, London, Ontario, N6A 5C1, Canada
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30
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Martinez RCR, Seney SL, Summers KL, Nomizo A, De Martinis ECP, Reid G. Effect of Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 on the ability of Candida albicans to infect cells and induce inflammation. Microbiol Immunol 2009; 53:487-95. [PMID: 19703242 DOI: 10.1111/j.1348-0421.2009.00154.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Vulvovaginal candidiasis, a high prevailing infection worldwide, is mainly caused by Candida albicans. Probiotic Lactobacillus reuteri RC-14 and Lactobacillus rhamnosus GR-1 have been previously shown to be useful as adjuvants in the treatment of women with VVC. In order to demonstrate and better understand the anti-Candida activity of the probiotic microorganisms in an in vitro model simulating vaginal candidiasis, a human vaginal epithelial cell line (VK2/E6E7) was infected with C.albicans 3153a and then challenged with probiotic L. rhamnosus GR-1 and/or L. reuteri RC-14 or their respective CFS (alone or in combination). At each time point (0, 6, 12 and 24 hr), numbers of yeast, lactobacilli and viable VK2/E6E7 cells were determined and, at 0, 6 and 12 hr, the supernatants were measured for cytokine levels. We found that C. albicans induced a significant increase in IL-1alpha and IL-8 production by VK2/E6E7 cells. After lactobacilli challenge, epithelial cells did not alter IL-6, IL-1alpha, RANTES and VEGF levels. However, CFS from the probiotic microorganisms up-regulated IL-8 and IP-10 levels secreted by VK2/E6E7 cells infected with C. albicans. At 24 hr of co-incubation, L. reuteri RC-14 alone and in combination with L. rhamnosus GR-1 decreased the yeast population recoverable from the cells. In conclusion, L. reuteri RC-14 alone and together with L. rhamnosus GR-1 have the potential to inhibit the yeast growth and their CFS may up-regulate IL-8 and IP-10 secretion by VK2/E6E7 cells, which could possibly have played an important role in helping to clear VVC in vivo.
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Affiliation(s)
- Rafael C R Martinez
- Department of Clinical, Toxicological and Bromatological Analysis, Faculty of Pharmaceutical Sciences of Ribeirão Preto, Avenida do Café s/n, Campus of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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31
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Abstract
Despite the pivotal role of dendritic cells (DC) in shaping immunity, little is known about their functionality in type 1 diabetes. Moreover, due to the paucity of DC in vivo, functional studies have relied largely upon in vitro-expanded cells to elucidate type 1 diabetes-associated functional abnormalities. In this study, we provide a comprehensive analysis of the functional capabilities of in vivo-derived DC subsets from NOD mice by comparing DC to other NOD APC types and to DC from autoimmune-resistant strains. NOD DC closely resemble those from nonautoimmune strains with respect to costimulation and cytokine production. The exception is the CD8alpha(+)CD11b(-)DC subset which is numerically reduced in NOD spleens, but not in the pancreatic lymph nodes, while DC from both tissues produce little IL-12 in this strain. This defect results in unusual deferral toward macrophage-derived IL-12 in NOD mice; NOD macrophages produce aberrantly high IL-12 levels that can overcompensate for the DC defect in Th1 polarization. APC subset use for autoantigen presentation also differs in NOD mice. NOD B cells overshadow DC at activating islet-reactive T cells, whereas DC and B cells in NOD-resistant mice are functionally comparable. Differential involvement of APC subsets in T cell activation and tolerance induction may prove to be a crucial factor in the selection and expansion of autoreactive T cells.
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Affiliation(s)
- Annette M Marleau
- Department of Microbiology and Immunology, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
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32
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Summers KL, Marleau AM, Mahon JL, McManus R, Hramiak I, Singh B. Reduced IFN-alpha secretion by blood dendritic cells in human diabetes. Clin Immunol 2006; 121:81-9. [PMID: 16859998 DOI: 10.1016/j.clim.2006.05.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [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: 03/21/2006] [Revised: 05/18/2006] [Accepted: 05/30/2006] [Indexed: 10/24/2022]
Abstract
Characterization of dendritic cells (DC) in human diabetes has been restricted to monocyte-derived DC in type 1 diabetes, whose physiological relevance to endogenous DC is uncertain. Here, we provide the first report characterizing the phenotype and function of endogenous DC subsets in type 1 and type 2 diabetes. We show that DC subsets in each diabetic group exhibit normal properties concerning frequency and activation state, as determined using 4-color flow cytometry of whole blood cells. DC maturation is also intact as confirmed by their efficacious ability to stimulate T cell proliferation in an allogeneic MLR assay. Yet we found that DC are poor producers of IFN-alpha (P < 0.05) in human diabetes. IFN-alpha is a potent antiviral agent and therefore its reduced levels may interfere with T cell-mediated immune responses leading to increased susceptibility and persistence of infections in persons with diabetes.
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Affiliation(s)
- Kelly L Summers
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
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33
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Hock BD, O'Donnell JL, Taylor K, Steinkasserer A, McKenzie JL, Rothwell AG, Summers KL. Levels of the soluble forms of CD80, CD86, and CD83 are elevated in the synovial fluid of rheumatoid arthritis patients. Tissue Antigens 2006; 67:57-60. [PMID: 16451202 DOI: 10.1111/j.1399-0039.2005.00524.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The release of soluble forms of CD80 (sCD80), CD86 (sCD86), and CD83 (sCD83) provide a potentially powerful immunoregulatory mechanism. We therefore investigated the potential presence and relative levels of these molecules in the synovial fluid (SF) and serum of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Serum and SF levels were measured by enzyme-linked immunosorbent assay. Serum levels of sCD80, sCD86, and sCD83 in RA and OA patients were similar to those present in normal donor serum (NDS) and the SF of OA patients. In contrast, when compared with NDS and OA SF levels, almost all RA SF samples had elevated sCD83 levels (32/35, >0.63 ng/ml) and a substantial proportion had elevated sCD80 (13/29, >0.22 ng/ml) or sCD86 (16/33, >2.31 ng/ml) levels. Analysis of matched pairs of serum and SF from RA patients demonstrated that the SF/serum ratio for sCD80 (95% CI = 1.7-3), sCD86 (95% CI = 1.5-3.1), and sCD83 (95% CI = 3.6-7.8) levels was >1 in almost all patients. In conclusion, this study shows that the SF from almost all RA patients contain elevated levels of sCD83 and the majority of these samples also contain elevated levels of sCD80 and/or sCD86. These molecules may play a role in modulating immune responses within the rheumatoid joint.
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Affiliation(s)
- B D Hock
- Haematology Research Group, Christchurch Hospital, New Zealand.
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Abstract
The characterization of dendritic cells (DCs) in diabetes has primarily examined in vitro-generated DCs. In this study, we have compared the composition and phenotype of naturally occurring DCs within the peripheral blood of subjects with type 1 diabetes, latent-onset autoimmune diabetes in adults, and nondiabetic controls. We find that circulatory DC subsets exist in normal frequencies and phenotypic states in diabetic patients. In vivo, DCs were located around the pancreatic islets in type 1 diabetic patients, but were absent in pancreatic tissue of normal controls. These findings provide new insight toward understanding the pathological role of DCs in type 1 diabetes.
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Affiliation(s)
- Kelly L Summers
- John P. Robarts Research Institute, London, Ontario N6A 5C1, Canada.
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Abstract
Heterogeneous expression of several antigens on the three currently defined tonsil dendritic cell (DC) subsets encouraged us to re-examine tonsil DCs using a new method that minimized DC differentiation and activation during their preparation. Three-color flow cytometry and dual-color immunohistology was used in conjunction with an extensive panel of antibodies to relevant DC-related antigens to analyze lin(-) HLA-DR(+) tonsil DCs. Here we identify, quantify, and locate five tonsil DC subsets based on their relative expression of the HLA-DR, CD11c, CD13, and CD123 antigens. In situ localization identified four of these DC subsets as distinct interdigitating DC populations. These included three new interdigitating DC subsets defined as HLA-DR(hi) CD11c(+) DCs, HLA-DR(mod) CD11c(+) CD13(+) DCs, and HLA-DR(mod) CD11c(-) CD123(-) DCs, as well as the plasmacytoid DCs (HLA-DR(mod) CD11c(-) CD123(+)). These subsets differed in their expression of DC-associated differentiation/activation antigens and co-stimulator molecules including CD83, CMRF-44, CMRF-56, 2-7, CD86, and 4-1BB ligand. The fifth HLA-DR(mod) CD11c(+) DC subset was identified as germinal center DCs, but contrary to previous reports they are redefined as lacking the CD13 antigen. The definition and extensive phenotypic analysis of these five DC subsets in human tonsil extends our understanding of the complexity of DC biology.
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Affiliation(s)
- K L Summers
- Hematology/Immunology Research Group, Christchurch Hospital, Christchurch, New Zealand
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Hock BD, Fearnley DB, Boyce A, McLellan AD, Sorg RV, Summers KL, Hart DN. Human dendritic cells express a 95 kDa activation/differentiation antigen defined by CMRF-56. Tissue Antigens 1999; 53:320-34. [PMID: 10323336 DOI: 10.1034/j.1399-0039.1999.530402.x] [Citation(s) in RCA: 49] [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] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Despite the unique functions of dendritic cells (DC), only two cell surface antigens (CMRF-44 and CD83) with relatively restricted expression on human DC have been described to date. We describe a third mAb, CMRF-56, which recognizes another DC early activation/differentiation antigen with limited expression on other haemopoietic cell populations. Circulating blood leukocytes did not express the CMRF-56 antigen and, following either in vitro culture or activation of PBMC populations, CMRF-56 antigen expression was detected only on DC and a subpopulation of CD19+ lymphocytes. Circulating blood DC were CMRF-56 but induced expression within 6 h of in vitro culture. This, together with the finding that tonsil and synovial fluid DC upregulate the antigen following short-term in vitro culture, confirmed that CMRF-56 recognizes an early activation antigen on DC. Isolated Langerhan's cells, dermal DC, migratory dermal DC and monocyte derived DC (GM-CSF/IL-4/TNFalpha) also express the CMIRF-56 antigen. Antigen modulation studies demonstrated that the amount of cell surface bound CMRF-56 and CMRF-44 (but not CD83) mAb was dramatically reduced by short-term incubation at 37 degrees C. This effect was not due to internalization and the reduction in CMRF-56 binding was a reversible, temperature-dependent process. In contrast, the decrease in CMRF-44 binding was irreversible, suggesting that following ligation the CMRF-44 antigen undergoes an irreversible conformational change or shedding at 37 degrees C. Western blotting confirmed that CMRF-56 recognizes a previously undescribed 95 kDa activation antigen whose cellular distribution and expression kinetics overlaps with, but is clearly distinguishable from, that of the CD83 and CMRF-44 antigens. CMRF-56 therefore provides a useful additional marker for studies on human DC.
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Affiliation(s)
- B D Hock
- Haematology/Immunology Research Group, Christchurch Hospital, New Zealand
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Summers KL, O'Donnell JL, Heiser A, Highton J, Hart DN. Synovial fluid transforming growth factor beta inhibits dendritic cell-T lymphocyte interactions in patients with chronic arthritis. Arthritis Rheum 1999; 42:507-18. [PMID: 10088774 DOI: 10.1002/1529-0131(199904)42:3<507::aid-anr16>3.0.co;2-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE To examine whether rheumatoid synovial fluid (SF) inhibits dendritic cell (DC) expression of the CD80 and CD86 costimulator molecules and contributes to SF T lymphocyte hyporesponsiveness. METHODS Cell-free rheumatoid SF was tested for its effect on DC-stimulated autologous/allogeneic mixed lymphocyte reactions and for its effect on DC surface antigen expression, as assessed by flow cytometry. Blocking monoclonal antibodies were used to identify the SF cytokines that inhibited DC-T lymphocyte interactions. RESULTS Low concentrations of SF (2.5%) could inhibit DC-mediated autologous and allogeneic T lymphocyte proliferation. This inhibitory effect could be reversed by neutralizing transforming growth factor beta (TGFbeta) and interleukin-2 (IL-2), but not by IL-12, in the SF. Hyaluronic acid, IL-6, IL-10, and tumor necrosis factor alpha were not associated with SF inhibition. In vitro culture alone and crosslinking with the CD40 ligand up-regulated DC CD80/CD86 expression and costimulator function, and this was not affected by inclusion of SF. In the presence of SF, DC clustered with autologous T lymphocytes showed decreased CD80 and CD86 expression, and variable CD80/CD86 decreases were observed on DC clustered with allogeneic T lymphocytes. CONCLUSIONS TGFbeta in SF appears to suppress T lymphocyte function, which may affect both signaling to DC and the induction of DC costimulator function.
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Troy AJ, Summers KL, Davidson PJ, Atkinson CH, Hart DN. Minimal recruitment and activation of dendritic cells within renal cell carcinoma. Clin Cancer Res 1998; 4:585-93. [PMID: 9533525] [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: 02/07/2023]
Abstract
Dendritic cells (DCs) are predicted to participate in natural tumor immunity by migrating into tumors, where they acquire antigen, undergo activation, and migrate to lymph nodes to initiate a T-lymphocyte response against tumor-associated antigens. The presence of DCs using defined lineage markers and their function in human tumors has not been assessed previously. The monoclonal antibodies against CMRF-44 and CD83, which are differentiation/activation antigens on DCs, were used in immunohistological and flow cytometry studies to analyze the DC subtypes infiltrating 14 cases of human renal cell carcinoma (RCC). The functional immunocompetence of the DCs isolated from RCC was assessed by testing their ability to stimulate an allogeneic mixed leukocyte reaction. The majority of leukocytes present within the RCC were macrophages (62% +/- 14.7) or T lymphocytes (19% +/- 9.5), with CD45+ HLA-DR+ lineage-negative putative DCs accounting for less than 10% of the leukocytes present. Of these, a subset, comprising less than 1% of total leukocytes, had an activated CMRF-44+ or CD83+ DC phenotype. Activated CMRF-44+ and CD83+ DCs were more evident outside the tumor in association with T-lymphocyte clusters. The number of CMRF-44+ DCs correlated closely with the number of S-100-positive DCs. Isolation of DCs from eight RCCs was achieved, and flow cytometry studies confirmed the small proportion of activated CMRF-44+ DCs. The CMRF-44+ DCs stimulated an allogeneic mixed leukocyte reaction, but the CMRF-44- DCs (normal tissue DC precursors and other cells) failed to do so. These results suggest that RCCs recruit few DCs into the tumor substance, and the tumor environment fails to initiate the expected protective activation of DCs. These two mechanisms, amongst others, may contribute to tumor escape from immunosurveillance. In vitro loading of DCs with tumor-associated antigens may be a useful therapeutic maneuver.
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Affiliation(s)
- A J Troy
- Department of Urology, Christchurch Hospital, New Zealand
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Summers KL, Kem WR, Giacobini E. Nicotinic agonist modulation of neurotransmitter levels in the rat frontoparietal cortex. Jpn J Pharmacol 1997; 74:139-46. [PMID: 9243321 DOI: 10.1254/jjp.74.139] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Anabaseine is a naturally occurring toxin that stimulates a variety of neuronal and muscle nicotinic receptors. GTS-21 [3-(2,4-dimethoxybenzylidene)anabaseine], an anabaseine derivative, selectively stimulates alpha 7-containing nicotinic receptors. Here we report the first in vivo study of the effects of these two nicotinic agonists on cortical extracellular acetylcholine (ACh), dopamine (DA), norepinephrine (NE) and serotonin (5-HT) levels, measured with a microdialysis probe placed within the frontoparietal cortex in the absence of a cholinesterase inhibitor. At 3.6 mumol/kg, s.c., anabaseine increased cortical ACh and NE above baseline values without significantly affecting DA and 5-HT. The ACh and NE elevations were inhibited by i.p. pre-administration (4.9 mumol/kg) of the nicotinic antagonist mecamylamine (Mec). In contrast, GTS-21 (3.6 mumol/kg, s.c.) significantly increased NE and DA without affecting ACh and 5-HT levels. Following Mec injection, GTS-21 increased ACh 25-fold and 5-HT 13-fold, while NE and DA levels were slightly decreased in comparison with GTS-21 alone. We suggest that at the dose used, Mec may preferentially block high affinity nicotinic receptors which normally provide an inhibitory influence upon ACh release, thereby permitting expression of the complete stimulatory effect of GTS-21 on neuronal alpha 7-receptors. GTS-21 and other receptor subtype-selective nicotinic agonists should be helpful in clarifying the roles of particular nicotinic receptors in modulating cortical neurotransmitter levels.
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Affiliation(s)
- K L Summers
- Department of Pharmacology, Southern Illinois University, Springfield 62794-9230, USA
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Hart DN, Clark GJ, Dekker JW, Fearnley DB, Kato M, Hock BD, McLellan AD, Neil T, Sorg RV, Sorg U, Summers KL, Vuckovic S. Dendritic cell surface molecules. A proliferating field. Adv Exp Med Biol 1997; 417:439-42. [PMID: 9286400 DOI: 10.1007/978-1-4757-9966-8_72] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- D N Hart
- Haematology/Immunology/Transfusion Medicine Research Group, Christchurch Hospital, New Zealand
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Summers KL, Lippiello P, Giacobini E. A microdialysis study of the effects of the nicotinic agonist RJR-2403 on cortical release of acetylcholine and biogenic amines. Neurochem Res 1996; 21:1181-6. [PMID: 8923478 DOI: 10.1007/bf02532393] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Transcortical dialysis was employed to investigate the effects of subcutaneous (s.c.) injections of RJR-2403 (1.2-7.2 mumol/kg) on extracellular levels of acetylcholine (ACh), norepinephrine (NE), dopamine (DA), and serotonin (5-HT) in rat. Systemic administration of RJR-2403 produced a 90% increase of cortical extracellular ACh levels that persisted for up to 90 minutes after injection. Norepinephrine and DA release were increased 124% and 131% above basal values, respectively. Serotonin (5-HT) levels in the dialysate were also significantly elevated by RJR-2403 (3.6 mumol/kg, s.c.) 70% above baseline at 90 minutes post-injection. Comparison of these responses to those of (-)nicotine from a previous study reveals little difference between the two compounds in their ability to influence cortical neurotransmitter release following systemic administration.
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Affiliation(s)
- K L Summers
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield 62794-1222, USA
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Williams LA, McLellan AD, Summers KL, Sorg RV, Fearnley DB, Hart DN. Identification of a novel dendritic cell surface antigen defined by carbohydrate specific CD24 antibody cross-reactivity. Immunol Suppl 1996; 89:120-5. [PMID: 8911149 PMCID: PMC1456670 DOI: 10.1046/j.1365-2567.1996.d01-720.x] [Citation(s) in RCA: 15] [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: 02/03/2023]
Abstract
Dendritic cells (DC) are characterized as leucocytes that lack mature lineage specific markers and stimulate naive T-lymphocyte proliferation in vitro and in vivo. The mouse heat stable antigen (HSA) participates in T lymphocyte co-stimulation and is expressed by DC isolated from thymus, skin and spleen. The human HSA homologue, CD24, is predominantly expressed by B lymphocytes and granulocytes, but its expression on DC has not been studied in detail. CD24 clearly participates in B-lymphocyte signalling but co-stimulatory activity for T lymphocytes has not yet been described. We have examined the expression of CD24 on human peripheral blood DC populations isolated directly or following in vitro culture. The CD24 antigen was absent from blood DC however, cross-reactive sialylated carbohydrate epitopes were detected on DC with some CD24 monoclonal antibodies (mAb). These CD24 mAb define a protein surface antigen, which is expressed by an immature or resting subpopulation of peripheral blood DC and is down-regulated following activation differentiation in vitro.
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Affiliation(s)
- L A Williams
- Haemetology Immunology Research Group, Christchurch School of Medicine, New Zealand
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Summers KL, O'Donnell JL, Williams LA, Hart DN. Expression and function of CD80 and CD86 costimulator molecules on synovial dendritic cells in chronic arthritis. Arthritis Rheum 1996; 39:1287-91. [PMID: 8702435 DOI: 10.1002/art.1780390804] [Citation(s) in RCA: 24] [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] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To examine CD86 expression on dendritic cells isolated from the synovial fluid (SFDC) of patients with chronic arthritis, and to determine the importance of both CD80 and CD86 molecules in SFDC-T lymphocyte interactions. METHODS CD86 messenger RNA (mRNA) and surface expression were analyzed in SFDC using reverse transcriptase-polymerase chain reaction and flow cytometry, respectively. The costimulator activity of the SFDC CD80 and CD86 molecules was determined by allogeneic mixed lymphocyte reaction (MLR). CD80 and CD86 induction on SFDC during in vitro culture was also examined. RESULTS Fresh SFDC either lacked or showed very weak surface expression of CD86 molecules (as shown previously for CD80), yet contained CD86 mRNA. CD80 antibodies minimally inhibited an allogeneic MLR, whereas CD86 antibodies and CTLA-4 Ig showed significant inhibition. Both CD80 and CD86 molecules were inconsistently induced on SFDC following culture in either media, interferon-gamma, or granulocyte-macrophage colony-stimulating factor. CONCLUSION SFDC may be defective antigen-presenting cells in vivo. The ability of CD80 and CD86 molecules to be induced and become functional on SFDC in vitro implies the presence of a negative regulatory compound(s) in the synovial environment.
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Summers KL, Lippiello P, Verhulst S, Giacobini E. 5-fluoronicotine, noranhydroecgonine, and pyridyl-methylpyrrolidine release acetylcholine and biogenic amines in rat cortex in vivo. Neurochem Res 1995; 20:1089-94. [PMID: 8570014 DOI: 10.1007/bf00995564] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effects of nicotinic receptor agonists 5-fluoronicotine, noranhydroecgonine and pyridyl-methylpyrrolidine on the cortical release of acetylcholine (ACh), norepinephrine (NE), dopamine (DA) and serotonin (5-HT) were investigated with microdialysis in rat. 5-Fluoronicotine significantly elevated ACh to 76% above basal values and DA to 69% above baseline. Pyridyl-methylpyrrolidine significantly increased the release of ACh to 39% above basal values and NE to 63% above baseline. Noranhydroecgonine significantly elevated NE to 64% above basal values and DA to 147% above baseline. 5-Fluoronicotine did not affect NE release; pyridylmethylpyrrolidine did not alter DA release; and noranhydroecgonine did not significantly elevate ACh release. None of these agonists increased the release of 5-HT. All responses were blocked by prior administration of mecamylamine, a nicotinic receptor antagonist. The distinctive neurotransmitter-related profiles for the three agonists are suggestive of activity at subtypes of nicotinic receptors, an effect that may be related to the structural diversity of these compounds.
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Affiliation(s)
- K L Summers
- Dept. Pharmacology, Southern Illinois University School of Medicine, Springfield 62794-1222, USA
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Summers KL, O'Donnell JL, Hoy MS, Peart M, Dekker J, Rothwell A, Hart DN. Monocyte-macrophage antigen expression on chondrocytes. J Rheumatol 1995; 22:1326-34. [PMID: 7562767] [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: 01/26/2023]
Abstract
OBJECTIVE To characterize chondrocytes in normal and arthritic joints and compare their phenotype to that of synovial macrophages present in rheumatoid joints. METHODS Using an immunoperoxidase staining technique, we examined the presence and distribution of a number of leukocyte activation and differentiation antigens on samples of cartilage obtained from resected joints of normal controls and subjects with rheumatoid arthritis or osteoarthritis. RESULTS Chondrocytes in each group were CD14+, CD68+, Thy-1+, CD11a+, CD18+, MAX.3-, and MAX.24-. Staining was variable for MAX.1 and CD45. HLA-DR and CD71 were expressed only on cells located in the superficial layer of rheumatoid cartilage. We found lower levels of expression of CD14 on chondrocytes in arthritic joints, whereas CD58 was expressed at higher levels. Surface expression of CD14 was confirmed on normal chondrocytes using flow cytometry and further supported by the detection of CD14 mRNA by polymerase chain reaction. CONCLUSION Our findings demonstrate that chondrocytes express several antigens that are also found on monocytes and macrophages.
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Affiliation(s)
- K L Summers
- Haematology/Immunology Research Group, Christchurch School of Medicine, New Zealand
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Summers KL, Giacobini E. Effects of local and repeated systemic administration of (-)nicotine on extracellular levels of acetylcholine, norepinephrine, dopamine, and serotonin in rat cortex. Neurochem Res 1995; 20:753-9. [PMID: 7566373 DOI: 10.1007/bf01705545] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Systemically administered (-)nicotine (0.2-1.2 mg/kg, s.c.) significantly increased the release of acetylcholine (ACh), norepinephrine (NE) and dopamine (DA) in rat cortex. The lowest dose of (-)nicotine examined (0.2 mg/kg, s.c.) also significantly elevated extracellular serotonin (5-HT) levels, and the maximal increases of extracellular ACh (122% at 90 min post injection) and DA levels (249% at 120 min post-injection) were observed following this dose. In contrast, the maximal increase of NE release (157% at 30 min post-injection) was observed following the highest dose of (-)nicotine injected (1.2 mg/kg, s.c.). This higher dose consistently produced generalized seizures. Repeating the (-)nicotine (0.58 mg/kg, s.c.) injection four hours after the first administration significantly elevated extracellular NE levels and also appeared to increase DA and ACh release. In addition, extracellular ACh and DA levels increased significantly in the dialysate after (-)nicotine was administered directly to the neocortex through the microdialysis probe membrane. Norepinephrine levels appeared to be elevated in the cortex following local administration as well.
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Affiliation(s)
- K L Summers
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield 62794-9230, USA
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47
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Abstract
Dendritic cells (DC) act as potent primary antigen-presenting cells in many immune responses and therefore may have a role in the initiation and perpetuation of the synovial inflammation in chronic inflammatory arthritis. To examine their function, it is important to isolate fresh DC from arthritic joints without aberrant activation. We have developed a technique using minimal cell manipulation to isolate DC from the synovial fluid of chronic arthritic patients. Using this method, DC were shown to be potent allostimulatory cells, with 63-90% of cells lacking lineage-specific markers (lin-), but positive for MHC class II molecules. Two morphologically distinct populations of these cells were identified in 10 out of 13 DC preparations. Both populations expressed CD40, intercellular adhesion molecule-1 (ICAM-1), ICAM-2, ICAM-3 and leucocyte function associated antigen-3 (LFA-3), but the predominant population, which was larger and more typical of cultured blood DC, had a higher density of these antigens compared with the minor population, which were smaller and morphologically similar to lymphocytes. Two new MoAbs which label activated human blood DC, HB15 (CD83) and CMRF-44, were tested. CD83 labelled very weakly or not at all, whereas CMRF-44 was positive on the larger cells only. Likewise, the costimulator molecule, B7/BB1 (CD80), was not detected on the surface of either synovial lin- cell population, reverse transcriptase polymerase chain reaction (RT-PCR) showed little or no CD80 mRNA, and no binding of the CTLA-4Ig fusion protein was found. These results suggest that synovial DC are not, despite the inflammatory environment, in a fully activated state.
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Affiliation(s)
- K L Summers
- Haematology/Immunology Research Group, Christchurch Hospital, New Zealand
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48
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Summers KL, O'Donnell JL, Daniels PB, Hart DN. Improved isolation of dendritic cells in chronic arthritic joints reveals no B7 (CD80) surface expression. Adv Exp Med Biol 1995; 378:561-3. [PMID: 8526142 DOI: 10.1007/978-1-4615-1971-3_126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- K L Summers
- Haematology/Immunology Research Group, Christchurch Hospital, New Zealand
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Abstract
The site of T lymphocyte activation in chronic arthritis is unknown. Peripheral blood (PB) lymphocytes from chronic arthritis patients are in a 'naive' or non-activated state, as defined by expression of the CD45RA antigen and lack of HLA class II expression. In contrast, most synovial fluid (SF) T lymphocytes express a 'memory' or activated phenotype, as defined by the CD45RO antigen and high HLA class II expression. Following stimulation, naive cells lose CD45RA and gain CD45RO expression to become memory cells with a transitional stage of dual CD45RA, CD45RO antigen expression. To localize where this change in phenotype occurs we used dual colour immunofluorescence labelling to compare the percentage of dual CD45RA, CD45RO-positive T lymphocytes in PB and SF from chronic arthritic patients and from normal PB, assuming this population would be increased at the primary site of T lymphocyte activation. Expression of the intermediate and late activation marker, HLA-DR, was also analysed using dual colour immunofluorescence labelling. The percentage of dual positive T lymphocytes was similar between arthritic PB, SF, and normal PB, as was the density of both CD45RA and CD45RO antigens. Thus, CD45 isoform expression did not indicate where T lymphocytes were activated. However, we identified a previously unreported population of CD45RA+ CD45RO+ HLA-DR- T lymphocytes in arthritic and normal PB. In SF, this population was absent, but a substantial number of dual CD45RA, CD45RO-positive HLA-DR+ T lymphocytes were identified. This population would not be predicted by the current model of T lymphocyte activation. Division of T lymphocytes into functional groups on the basis of CD45 isoform expression is likely to be more complicated than previously thought. Based on our findings we propose an alternative model of T lymphocyte differentiation.
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Affiliation(s)
- K L Summers
- Haematology/Immunology Research Group, Christchurch Hospital, New Zealand
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Maccato M, Faro S, Summers KL. Wound infections after cesarean section with Mycoplasma hominis and Ureaplasma urealyticum. A report of three cases. Diagn Microbiol Infect Dis 1990; 13:363-5. [PMID: 2282776 DOI: 10.1016/0732-8893(90)90002-d] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [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: 12/31/2022]
Abstract
Mycoplasma hominis and Ureaplasma urealyticum were isolated from the surgical wounds of three patients who developed endometritis and a wound infection after cesarean section. In all patients, aspiration of the incision yielded a cloudy serosanguinous exudate. Gram stain of the fluid revealed numerous white blood cells but no bacteria. All patients responded to antibiotic therapy and local wound care.
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Affiliation(s)
- M Maccato
- Baylor College of Medicine, Houston, Texas 77030
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