1
|
Dowling MR, Turtle CJ. ICANS prophylaxis: potentially transformative but elusive. Blood Adv 2023; 7:6782-6784. [PMID: 37962875 PMCID: PMC10692280 DOI: 10.1182/bloodadvances.2023011027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023] Open
Affiliation(s)
- Mark R Dowling
- Clinical Haematology Peter MacCallum Cancer Centre and Royal Melbourne Hospital, and the Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne VIC 3052, Australia
| | - Cameron J Turtle
- Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Camperdown NSW 2050, Australia
| |
Collapse
|
2
|
Robinson MJ, Ding Z, Dowling MR, Hill DL, Webster RH, McKenzie C, Pitt C, O'Donnell K, Mulder J, Brodie E, Hodgkin PD, Wong NC, Quast I, Tarlinton DM. Intrinsically determined turnover underlies broad heterogeneity in plasma-cell lifespan. Immunity 2023:S1074-7613(23)00183-8. [PMID: 37164016 DOI: 10.1016/j.immuni.2023.04.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [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: 10/03/2022] [Revised: 02/24/2023] [Accepted: 04/14/2023] [Indexed: 05/12/2023]
Abstract
Antibodies produced by antibody-secreting plasma cells (ASCs) underlie multiple forms of long-lasting immunity. Here we examined the mechanisms regulating ASC turnover and persistence using a genetic reporter to time-stamp ASCs. This approach revealed ASC lifespans as heterogeneous and falling on a continuum, with only a small fraction surviving for >60 days. ASC longevity past 60 days was independent of isotype but correlated with a phenotype that developed progressively and ultimately associated with an underlying "long-lived" ASC (LL ASC)-enriched transcriptional program. While some of the differences between LL ASCs and other ASCs appeared to be acquired with age, other features were shared with some younger ASCs, such as high CD138 and CD93. Turnover was unaffected by altered ASC production, arguing against competition for niches as a major driver of turnover. Thus, ASC turnover is set by intrinsic lifespan limits, with steady-state population dynamics governed by niche vacancy rather than displacement.
Collapse
Affiliation(s)
- Marcus James Robinson
- Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia.
| | - Zhoujie Ding
- Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia
| | - Mark R Dowling
- Department of Clinical Haematology, Royal Melbourne Hospital and Peter MacCallum Cancer Centre, 305 Grattan St, Parkville, VIC 3000, Australia; Immunology Division, The Walter and Eliza Hall Institute, 1G Royal Parade, Parkville, VIC 3050, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Danika L Hill
- Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia
| | - Rosela H Webster
- Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia
| | - Craig McKenzie
- Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia
| | - Catherine Pitt
- Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia
| | - Kristy O'Donnell
- Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia
| | - Jesse Mulder
- Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia
| | - Erica Brodie
- Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia; Monash Bioinformatics Platform, Central Clinical School, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia
| | - Philip D Hodgkin
- Immunology Division, The Walter and Eliza Hall Institute, 1G Royal Parade, Parkville, VIC 3050, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Nick C Wong
- Monash Bioinformatics Platform, Central Clinical School, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia
| | - Isaak Quast
- Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia
| | - David M Tarlinton
- Department of Immunology, Alfred Medical Research and Education Precinct, Monash University, Melbourne, VIC 3004, Australia.
| |
Collapse
|
3
|
Robinson MJ, Dowling MR, Pitt C, O’Donnell K, Webster RH, Hill DL, Ding Z, Dvorscek AR, Brodie EJ, Hodgkin PD, Quast I, Tarlinton DM. Long-lived plasma cells accumulate in the bone marrow at a constant rate from early in an immune response. Sci Immunol 2022; 7:eabm8389. [DOI: 10.1126/sciimmunol.abm8389] [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: 11/02/2022]
Abstract
Vaccines work largely by generating long-lived plasma cells (LLPCs), but knowledge of how such cells are recruited is sparse. Although it is clear that LLPCs preferentially originate in germinal centers (GCs) and relocate to survival niches in bone marrow where they can persist for decades, the issues of the timing of LLPC recruitment and the basis of their retention remain uncertain. Here, using a genetic timestamping system in mice, we show that persistent PCs accrue in bone marrow at an approximately constant rate of one cell per hour over a period spanning several weeks after a single immunization with a model antigen. Affinity-based selection was evident in persisting PCs, reflecting a relative and dynamic rather than absolute affinity threshold as evidenced by the changing pattern of V
H
gene somatic mutations conveying increased affinity for antigen. We conclude that the life span of persistent, antigen-specific PCs is in part intrinsic, preprogrammed, and varied and that their final number is related to the duration of the response in a predictable way. This implies that modulating vaccines to extend the duration of the GC reaction will enhance antibody-mediated protective immunity.
Collapse
Affiliation(s)
- Marcus James Robinson
- Department of Immunology and Pathology, Monash University, Level 6, Burnet Tower, 89 Commercial Road, Melbourne, VIC 3004, Australia
| | - Mark R. Dowling
- Department of Clinical Haematology, Royal Melbourne Hospital and Peter MacCallum Cancer Centre, 305 Grattan St., Parkville, VIC 3000, Australia
- Immunology Division, Walter and Eliza Hall Institute, 1G Royal Parade, Parkville, VIC 3050, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, VIC 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Catherine Pitt
- Department of Immunology and Pathology, Monash University, Level 6, Burnet Tower, 89 Commercial Road, Melbourne, VIC 3004, Australia
| | - Kristy O’Donnell
- Department of Immunology and Pathology, Monash University, Level 6, Burnet Tower, 89 Commercial Road, Melbourne, VIC 3004, Australia
| | - Rosela H. Webster
- Department of Immunology and Pathology, Monash University, Level 6, Burnet Tower, 89 Commercial Road, Melbourne, VIC 3004, Australia
| | - Danika L. Hill
- Department of Immunology and Pathology, Monash University, Level 6, Burnet Tower, 89 Commercial Road, Melbourne, VIC 3004, Australia
| | - Zhoujie Ding
- Department of Immunology and Pathology, Monash University, Level 6, Burnet Tower, 89 Commercial Road, Melbourne, VIC 3004, Australia
| | - Alexandra R. Dvorscek
- Department of Immunology and Pathology, Monash University, Level 6, Burnet Tower, 89 Commercial Road, Melbourne, VIC 3004, Australia
| | - Erica J. Brodie
- Department of Immunology and Pathology, Monash University, Level 6, Burnet Tower, 89 Commercial Road, Melbourne, VIC 3004, Australia
| | - Philip D. Hodgkin
- Immunology Division, Walter and Eliza Hall Institute, 1G Royal Parade, Parkville, VIC 3050, Australia
- Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Isaak Quast
- Department of Immunology and Pathology, Monash University, Level 6, Burnet Tower, 89 Commercial Road, Melbourne, VIC 3004, Australia
| | - David Mathew Tarlinton
- Department of Immunology and Pathology, Monash University, Level 6, Burnet Tower, 89 Commercial Road, Melbourne, VIC 3004, Australia
| |
Collapse
|
4
|
Lelliott EJ, Ramsbottom KM, Dowling MR, Shembrey C, Noori T, Kearney CJ, Michie J, Parish IA, Jordan MA, Baxter AG, Young ND, Brennan AJ, Oliaro J. NKG7 Enhances CD8+ T Cell Synapse Efficiency to Limit Inflammation. Front Immunol 2022; 13:931630. [PMID: 35874669 PMCID: PMC9299089 DOI: 10.3389/fimmu.2022.931630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 04/29/2022] [Accepted: 06/06/2022] [Indexed: 12/01/2022] Open
Abstract
Cytotoxic lymphocytes are essential for anti-tumor immunity, and for effective responses to cancer immunotherapy. Natural killer cell granule protein 7 (NKG7) is expressed at high levels in cytotoxic lymphocytes infiltrating tumors from patients treated with immunotherapy, but until recently, the role of this protein in cytotoxic lymphocyte function was largely unknown. Unexpectedly, we found that highly CD8+ T cell-immunogenic murine colon carcinoma (MC38-OVA) tumors grew at an equal rate in Nkg7+/+ and Nkg7-/- littermate mice, suggesting NKG7 may not be necessary for effective CD8+ T cell anti-tumor activity. Mechanistically, we found that deletion of NKG7 reduces the ability of CD8+ T cells to degranulate and kill target cells in vitro. However, as a result of inefficient cytotoxic activity, NKG7 deficient T cells form a prolonged immune synapse with tumor cells, resulting in increased secretion of inflammatory cytokines, including tumor necrosis factor alpha (TNF). By deleting the TNF receptor, TNFR1, from MC38-OVA tumors, we demonstrate that this hyper-secretion of TNF compensates for reduced synapse-mediated cytotoxic activity against MC38-OVA tumors in vivo, via increased TNF-mediated tumor cell death. Taken together, our results demonstrate that NKG7 enhances CD8+ T cell immune synapse efficiency, which may serve as a mechanism to accelerate direct cytotoxicity and limit potentially harmful inflammatory responses.
Collapse
Affiliation(s)
- Emily J Lelliott
- Centre for Cancer Immunotherapy, Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.,Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Density and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Kelly M Ramsbottom
- Centre for Cancer Immunotherapy, Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Mark R Dowling
- Centre for Cancer Immunotherapy, Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.,Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Density and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Carolyn Shembrey
- Centre for Cancer Immunotherapy, Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.,Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Density and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Tahereh Noori
- Centre for Cancer Immunotherapy, Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Conor J Kearney
- Centre for Cancer Immunotherapy, Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.,Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Density and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Jessica Michie
- Centre for Cancer Immunotherapy, Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Ian A Parish
- Centre for Cancer Immunotherapy, Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.,Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Density and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Margaret A Jordan
- College of Public Health, Medical & Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Alan G Baxter
- College of Public Health, Medical & Veterinary Sciences, James Cook University, Townsville, QLD, Australia.,Central Clinical School, Monash University, Prahran, VIC, Australia
| | - Neil D Young
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Amelia J Brennan
- Centre for Cancer Immunotherapy, Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.,Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Density and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Jane Oliaro
- Centre for Cancer Immunotherapy, Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.,Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Density and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| |
Collapse
|
5
|
Dowling MR, Dickinson M. Post CAR-T cytopenia: poorly understood and clinically challenging. Leuk Lymphoma 2022; 63:1774-1776. [DOI: 10.1080/10428194.2022.2095631] [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: 10/17/2022]
Affiliation(s)
- Mark R. Dowling
- Clinical Haematology, Peter MacCallum Cancer Centre, Melbourne, Australia
- Clinical Haematology, Royal Melbourne Hospital, Parkville, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia
| | - Michael Dickinson
- Clinical Haematology, Peter MacCallum Cancer Centre, Melbourne, Australia
- Clinical Haematology, Royal Melbourne Hospital, Parkville, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia
| |
Collapse
|
6
|
Stolz RG, Dowling MR, Lin BB, Mason K, Muhi S. Strongyloides
hyperinfection: a preventable complication of immunosuppression. Med J Aust 2022; 216:561-562. [DOI: 10.5694/mja2.51561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/13/2021] [Accepted: 10/29/2021] [Indexed: 11/17/2022]
Affiliation(s)
| | - Mark R Dowling
- Peter MacCallum Cancer Centre Melbourne VIC
- Melbourne Health Melbourne VIC
| | - Belinda B Lin
- Peter Doherty Institute for Infection and Immunity Melbourne VIC
| | - Kylie Mason
- Peter MacCallum Cancer Centre Melbourne VIC
- Melbourne Health Melbourne VIC
| | - Stephen Muhi
- Victorian Infectious Diseases Service Royal Melbourne Hospital Melbourne VIC
| |
Collapse
|
7
|
Dowling MR, Ballen KK. Neurological Complications after Allogeneic Transplantation - Can We Do Better? Acta Haematol 2019; 142:193-194. [PMID: 31315109 DOI: 10.1159/000501297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 06/03/2019] [Indexed: 11/19/2022]
Affiliation(s)
- Mark R Dowling
- Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia,
| | - Karen K Ballen
- University of Virginia Cancer Center, Charlottesville, Virginia, USA
| |
Collapse
|
8
|
Dowling MR, Kan A, Heinzel S, Marchingo JM, Hodgkin PD, Hawkins ED. Regulatory T Cells Suppress Effector T Cell Proliferation by Limiting Division Destiny. Front Immunol 2018; 9:2461. [PMID: 30425712 PMCID: PMC6218578 DOI: 10.3389/fimmu.2018.02461] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [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: 06/07/2018] [Accepted: 10/04/2018] [Indexed: 11/23/2022] Open
Abstract
Understanding how the strength of an effector T cell response is regulated is a fundamental problem in immunology with implications for immunity to pathogens, autoimmunity, and immunotherapy. The initial magnitude of the T cell response is determined by the sum of independent signals from antigen, co-stimulation and cytokines. By applying quantitative methods, the contribution of each signal to the number of divisions T cells undergo (division destiny) can be measured, and the resultant exponential increase in response magnitude accurately calculated. CD4+CD25+Foxp3+ regulatory T cells suppress self-reactive T cell responses and limit pathogen-directed immune responses before bystander damage occurs. Using a quantitative modeling framework to measure T cell signal integration and response, we show that Tregs modulate division destiny, rather than directly increasing the rate of death or delaying interdivision times. The quantitative effect of Tregs could be mimicked by modulating the availability of stimulatory co-stimuli and cytokines or through the addition of inhibitory signals. Thus, our analysis illustrates the primary effect of Tregs on the magnitude of effector T cell responses is mediated by modifying division destiny of responding cell populations.
Collapse
Affiliation(s)
- Mark R Dowling
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Andrey Kan
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Susanne Heinzel
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Julia M Marchingo
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Philip D Hodgkin
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Edwin D Hawkins
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| |
Collapse
|
9
|
Dale P, Head V, Dowling MR, Taylor CW. Selective inhibition of histamine-evoked Ca 2+ signals by compartmentalized cAMP in human bronchial airway smooth muscle cells. Cell Calcium 2017; 71:53-64. [PMID: 29604964 PMCID: PMC5893132 DOI: 10.1016/j.ceca.2017.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/13/2017] [Accepted: 12/13/2017] [Indexed: 01/29/2023]
Abstract
β2-adrenoceptors, via cAMP and PKA, inhibit histamine-evoked Ca2+ signals in human bronchial airway smooth muscle cells. Responses to other Ca2+-mobilizing receptors are unaffected or minimally affected by cAMP. There is no consistent relationship between the amounts of cAMP produced by different stimuli and inhibition of histamine-evoked Ca2+ release. Local delivery of cAMP within hyperactive signaling junctions stimulates PKA. PKA inhibits an early step in the signaling pathway activated by H1 histamine receptors.
Intracellular Ca2+ and cAMP typically cause opposing effects on airway smooth muscle contraction. Receptors that stimulate these pathways are therapeutic targets in asthma and chronic obstructive pulmonary disease. However, the interactions between different G protein-coupled receptors (GPCRs) that evoke cAMP and Ca2+ signals in human bronchial airway smooth muscle cells (hBASMCs) are poorly understood. We measured Ca2+ signals in cultures of fluo-4-loaded hBASMCs alongside measurements of intracellular cAMP using mass spectrometry or [3H]-adenine labeling. Interactions between the signaling pathways were examined using selective ligands of GPCRs, and inhibitors of Ca2+ and cAMP signaling pathways. Histamine stimulated Ca2+ release through inositol 1,4,5-trisphosphate (IP3) receptors in hBASMCs. β2-adrenoceptors, through cAMP and protein kinase A (PKA), substantially inhibited histamine-evoked Ca2+ signals. Responses to other Ca2+-mobilizing stimuli were unaffected by cAMP (carbachol and bradykinin) or minimally affected (lysophosphatidic acid). Prostaglandin E2 (PGE2), through EP2 and EP4 receptors, stimulated formation of cAMP and inhibited histamine-evoked Ca2+ signals. There was no consistent relationship between the inhibition of Ca2+ signals and the amounts of intracellular cAMP produced by different stimuli. We conclude that β-adrenoceptors, EP2 and EP4 receptors, through cAMP and PKA, selectively inhibit Ca2+ signals evoked by histamine in hBASMCs, suggesting that PKA inhibits an early step in H1 receptor signaling. Local delivery of cAMP within hyperactive signaling junctions mediates the inhibition.
Collapse
Affiliation(s)
- Philippa Dale
- Department of Pharmacology,Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Victoria Head
- Novartis Institutes for BioMedical Research, Fabrikstrasse, CH-4056, Basel, Switzerland
| | - Mark R Dowling
- Novartis Institutes for BioMedical Research Inc., 250 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Colin W Taylor
- Department of Pharmacology,Tennis Court Road, Cambridge, CB2 1PD, UK.
| |
Collapse
|
10
|
Sattikar A, Dowling MR, Rosethorne EM. Endogenous lysophosphatidic acid (LPA 1 ) receptor agonists demonstrate ligand bias between calcium and ERK signalling pathways in human lung fibroblasts. Br J Pharmacol 2017; 174:227-237. [PMID: 27864940 DOI: 10.1111/bph.13671] [Citation(s) in RCA: 9] [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] [Received: 08/05/2016] [Revised: 11/09/2016] [Accepted: 11/10/2016] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE Human lung fibroblasts (HLF) express high levels of the LPA1 receptor, a GPCR that responds to the endogenous lipid mediator, lysophosphatidic acid (LPA). Several molecular species or analogues of LPA exist and have been detected in biological fluids such as serum and plasma. The most widely expressed of the LPA receptor family is the LPA1 receptor, which predominantly couples to Gq/11 , Gi/o and G12/13 proteins. This promiscuity of coupling raises the possibility that some of the LPA analogues may bias the LPA1 receptor towards one signalling pathway over another. EXPERIMENTAL APPROACH Here, we have explored the signalling profiles of a range of LPA analogues in HLF that endogenously express the LPA1 receptor. HLF were treated with LPA analogues and receptor activation monitored via calcium mobilization and ERK phosphorylation. KEY RESULTS These analyses demonstrated that the 16:0, 17:0, 18:2 and C18:1 LPA analogues appear to exhibit ligand bias between ERK phosphorylation and calcium mobilization when compared with 18:1 LPA, one of the most abundant forms of LPA that has been found in human plasma. CONCLUSION AND IMPLICATIONS The importance of LPA as a key signalling molecule is shown by its widespread occurrence in biological fluids and its association with disease conditions such as fibrosis and cancer. These findings have important, as yet unexplored, implications for the (patho-) physiological signalling of the LPA1 receptor, as it may be influenced not only by the concentration of endogenous ligand but the isoform as well.
Collapse
Affiliation(s)
- Afrah Sattikar
- Novartis Institutes for Biomedical Research, Horsham, UK
| | - Mark R Dowling
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Elizabeth M Rosethorne
- Novartis Institutes for Biomedical Research, Horsham, UK.,School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| |
Collapse
|
11
|
Lebois M, Dowling MR, Gangatirkar P, Hodgkin PD, Kile BT, Alexander WS, Josefsson EC. Regulation of platelet lifespan in the presence and absence of thrombopoietin signaling. J Thromb Haemost 2016; 14:1882-7. [PMID: 27344013 DOI: 10.1111/jth.13397] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Indexed: 01/09/2023]
Abstract
UNLABELLED Essentials We examined platelet survival in models of absent or enhanced thrombopoietin (TPO) signaling. Platelet lifespan is normal in transgenic mice with chronically enhanced TPO signaling. Mpl deficiency does not negatively affect platelet lifespan in the absence of thrombocytopenia. We conclude that TPO and its receptor Mpl are dispensable for platelet survival in adult mice. SUMMARY Background It is well established that thrombopoietin (TPO), acting via its receptor Mpl, is the major cytokine regulator of platelet biogenesis. The primary mechanism by which TPO signaling stimulates thrombopoiesis is via stimulation of Mpl-expressing hematopoietic progenitors; Mpl on megakaryocytes and platelets acts to control the amount of TPO available. TPO could potentially reduce platelet and/or megakaryocyte apoptosis, and therefore increase the platelet count. However, the effect of TPO receptor signaling on platelet survival is unresolved. Methods and results Here, we investigated platelet survival in mouse models of absent or enhanced TPO signaling. In the absence of thrombocytopenia, Mpl deficiency did not negatively influence platelet lifespan, and nor was platelet survival affected in transgenic mice with chronically increased TPO signaling. Conclusions We conclude that TPO and its receptor Mpl are dispensable for platelet survival in adult mice.
Collapse
Affiliation(s)
- M Lebois
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - M R Dowling
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - P Gangatirkar
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - P D Hodgkin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - B T Kile
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - W S Alexander
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - E C Josefsson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia.
| |
Collapse
|
12
|
Kan A, Pavlyshyn D, Markham JF, Dowling MR, Heinzel S, Zhou JHS, Marchingo JM, Hodgkin PD. Stochastic Measurement Models for Quantifying Lymphocyte Responses Using Flow Cytometry. PLoS One 2016; 11:e0146227. [PMID: 26742110 PMCID: PMC4704825 DOI: 10.1371/journal.pone.0146227] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 11/09/2015] [Indexed: 01/22/2023] Open
Abstract
Adaptive immune responses are complex dynamic processes whereby B and T cells undergo division and differentiation triggered by pathogenic stimuli. Deregulation of the response can lead to severe consequences for the host organism ranging from immune deficiencies to autoimmunity. Tracking cell division and differentiation by flow cytometry using fluorescent probes is a major method for measuring progression of lymphocyte responses, both in vitro and in vivo. In turn, mathematical modeling of cell numbers derived from such measurements has led to significant biological discoveries, and plays an increasingly important role in lymphocyte research. Fitting an appropriate parameterized model to such data is the goal of these studies but significant challenges are presented by the variability in measurements. This variation results from the sum of experimental noise and intrinsic probabilistic differences in cells and is difficult to characterize analytically. Current model fitting methods adopt different simplifying assumptions to describe the distribution of such measurements and these assumptions have not been tested directly. To help inform the choice and application of appropriate methods of model fitting to such data we studied the errors associated with flow cytometry measurements from a wide variety of experiments. We found that the mean and variance of the noise were related by a power law with an exponent between 1.3 and 1.8 for different datasets. This violated the assumptions inherent to commonly used least squares, linear variance scaling and log-transformation based methods. As a result of these findings we propose a new measurement model that we justify both theoretically, from the maximum entropy standpoint, and empirically using collected data. Our evaluation suggests that the new model can be reliably used for model fitting across a variety of conditions. Our work provides a foundation for modeling measurements in flow cytometry experiments thus facilitating progress in quantitative studies of lymphocyte responses.
Collapse
Affiliation(s)
- Andrey Kan
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Damian Pavlyshyn
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - John F. Markham
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Mark R. Dowling
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Susanne Heinzel
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Jie H. S. Zhou
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Julia M. Marchingo
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Philip D. Hodgkin
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
- * E-mail:
| |
Collapse
|
13
|
Sykes DA, Riddy DM, Stamp C, Bradley ME, McGuiness N, Sattikar A, Guerini D, Rodrigues I, Glaenzel A, Dowling MR, Mullershausen F, Charlton SJ. Investigating the molecular mechanisms through which FTY720-P causes persistent S1P1 receptor internalization. Br J Pharmacol 2015; 171:4797-807. [PMID: 24641481 DOI: 10.1111/bph.12620] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 10/09/2013] [Accepted: 11/18/2013] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE The molecular mechanism underlying the clinical efficacy of FTY720-P is thought to involve persistent internalization and enhanced degradation of the S1P1 receptor subtype (S1P1R). We have investigated whether receptor binding kinetics and β-arrestin recruitment could play a role in the persistent internalization of the S1P1R by FTY720-P. EXPERIMENTAL APPROACH [(3) H]-FTY720-P and [(33) P]-S1P were used to label CHO-S1P1/3Rs for binding studies. Ligand efficacy was assessed through [(35) S]-GTPγS binding and β-arrestin recruitment. Metabolic stability was evaluated using a bioassay measuring intracellular Ca(2+) release. CHO-S1P1/3R numbers were determined, following FTY720-P treatment using flow cytometry. KEY RESULTS The kinetic off-rate of [(3) H]-FTY720-P from the S1P1R was sixfold slower than from the S1P3R, and comparable to [(33) P]-S1P dissociation from S1P1/3Rs. S1P and FTY720-P stimulated [(35) S]-GTPγS incorporation to similar degrees, but FTY720-P was over 30-fold less potent at S1P3Rs. FTY720-P stimulated a higher level of β-arrestin recruitment at S1P1Rs, 132% of the total recruited by S1P. In contrast, FTY720-P was a weak partial agonist at S1P3R, stimulating just 29% of the total β-arrestin recruited by S1P. Internalization experiments confirmed that cell surface expression of the S1P1R but not the S1P3R was reduced following a pulse exposure to FTY720-P, which is metabolically stable unlike S1P. CONCLUSIONS AND IMPLICATIONS FTY720-P and S1P activation of the S1P1R results in receptor internalization as a consequence of an efficient recruitment of β-arrestin. The combination of slow off-rate, efficacious β-arrestin recruitment and metabolic stability all contribute to FTY720-P's ability to promote prolonged S1P1R internalization and may be critical factors in its efficacy in the clinic.
Collapse
Affiliation(s)
- David A Sykes
- Novartis Institutes for Biomedical Research, Horsham, West Sussex, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Marchingo JM, Kan A, Sutherland RM, Duffy KR, Wellard CJ, Belz GT, Lew AM, Dowling MR, Heinzel S, Hodgkin PD. T cell signaling. Antigen affinity, costimulation, and cytokine inputs sum linearly to amplify T cell expansion. Science 2014; 346:1123-7. [PMID: 25430770 DOI: 10.1126/science.1260044] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
T cell responses are initiated by antigen and promoted by a range of costimulatory signals. Understanding how T cells integrate alternative signal combinations and make decisions affecting immune response strength or tolerance poses a considerable theoretical challenge. Here, we report that T cell receptor (TCR) and costimulatory signals imprint an early, cell-intrinsic, division fate, whereby cells effectively count through generations before returning automatically to a quiescent state. This autonomous program can be extended by cytokines. Signals from the TCR, costimulatory receptors, and cytokines add together using a linear division calculus, allowing the strength of a T cell response to be predicted from the sum of the underlying signal components. These data resolve a long-standing costimulation paradox and provide a quantitative paradigm for therapeutically manipulating immune response strength.
Collapse
Affiliation(s)
- Julia M Marchingo
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Andrey Kan
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Robyn M Sutherland
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Ken R Duffy
- Hamilton Institute, National University of Ireland, Maynooth, Ireland
| | - Cameron J Wellard
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Gabrielle T Belz
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Andrew M Lew
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Mark R Dowling
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia. The Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Susanne Heinzel
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Philip D Hodgkin
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia. Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia.
| |
Collapse
|
15
|
Affiliation(s)
- Philip D Hodgkin
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, 3052 Victoria, Australia, and the Department of Medical Biology, University of Melbourne, Melbourne, 3010 Victoria, Australia
| | - Mark R Dowling
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, 3052 Victoria, Australia, and the Department of Medical Biology, University of Melbourne, Melbourne, 3010 Victoria, Australia
| | - Ken R Duffy
- Hamilton Institute, National University of Ireland, Maynooth, County Kildare, Ireland
| |
Collapse
|
16
|
Hawkins ED, Turner ML, Wellard CJ, Zhou JHS, Dowling MR, Hodgkin PD. Quantal and graded stimulation of B lymphocytes as alternative strategies for regulating adaptive immune responses. Nat Commun 2014; 4:2406. [PMID: 24009041 PMCID: PMC3778729 DOI: 10.1038/ncomms3406] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 08/06/2013] [Indexed: 12/15/2022] Open
Abstract
Lymphocytes undergo a typical response pattern following stimulation in vivo: they proliferate, differentiate to effector cells, cease dividing and predominantly die, leaving a small proportion of long-lived memory and effector cells. This pattern results from cell-intrinsic processes following activation and the influence of external regulation. Here we apply quantitative methods to study B-cell responses in vitro. Our results reveal that B cells stimulated through two Toll-like receptors (TLRs) require minimal external direction to undergo the basic pattern typical of immunity. Altering the stimulus strength regulates the outcome in a quantal manner by varying the number of cells that participate in the response. In contrast, the T-cell-dependent CD40 activation signal induces a response where division times and differentiation rates vary in relation to stimulus strength. These studies offer insight into how the adaptive antibody response may have evolved from simple autonomous response patterns to the highly regulable state that is now observed in mammals.
Collapse
Affiliation(s)
- E D Hawkins
- 1] Immunology Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia [2] Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia [3]
| | | | | | | | | | | |
Collapse
|
17
|
Dale PR, Cernecka H, Schmidt M, Dowling MR, Charlton SJ, Pieper MP, Michel MC. The pharmacological rationale for combining muscarinic receptor antagonists and β-adrenoceptor agonists in the treatment of airway and bladder disease. Curr Opin Pharmacol 2014; 16:31-42. [PMID: 24682092 PMCID: PMC4071415 DOI: 10.1016/j.coph.2014.03.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/03/2014] [Accepted: 03/04/2014] [Indexed: 02/07/2023]
Abstract
Muscarinic receptors increase smooth muscle tone in airways and urinary bladder. β-Adrenoceptors relax smooth muscle tone and oppose muscarinic contraction. Opposition involves transmitter release, signal transduction and receptor expression. This supports the combined use of muscarinic antagonists and β-adrenoceptor agonists.
Muscarinic receptor antagonists and β-adrenoceptor agonists are used in the treatment of obstructive airway disease and overactive bladder syndrome. Here we review the pharmacological rationale for their combination. Muscarinic receptors and β-adrenoceptors are physiological antagonists for smooth muscle tone in airways and bladder. Muscarinic agonism may attenuate β-adrenoceptor-mediated relaxation more than other contractile stimuli. Chronic treatment with one drug class may regulate expression of the target receptor but also that of the opposing receptor. Prejunctional β2-adrenoceptors can enhance neuronal acetylcholine release. Moreover, at least in the airways, muscarinic receptors and β-adrenoceptors are expressed in different locations, indicating that only a combined modulation of both systems may cause dilatation along the entire bronchial tree. While all of these factors contribute to a rationale for a combination of muscarinic receptor antagonists and β-adrenoceptor agonists, the full value of such combination as compared to monotherapy can only be determined in clinical studies.
Collapse
Affiliation(s)
- Philippa R Dale
- Department of Pharmacology, Cambridge University, Cambridge, UK
| | - Hana Cernecka
- University of Groningen, Department of Molecular Pharmacology, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, GRIAC, Groningen, The Netherlands
| | - Martina Schmidt
- University of Groningen, Department of Molecular Pharmacology, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Groningen Research Institute for Asthma and COPD, GRIAC, Groningen, The Netherlands
| | - Mark R Dowling
- Department of Molecular Pharmacology, Respiratory Diseases, Novartis Institutes for Biomedical Research, Horsham, UK
| | - Steven J Charlton
- Department of Molecular Pharmacology, Respiratory Diseases, Novartis Institutes for Biomedical Research, Horsham, UK
| | - Michael P Pieper
- Respiratory Diseases Research and Department of Translational Medicine & Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH, Ingelheim, Germany
| | - Martin C Michel
- Respiratory Diseases Research and Department of Translational Medicine & Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH, Ingelheim, Germany; Department of Pharmacology, Johannes Gutenberg University, Mainz, Germany.
| |
Collapse
|
18
|
Chakravorty R, Rawlinson D, Zhang A, Markham J, Dowling MR, Wellard C, Zhou JHS, Hodgkin PD. Labour-efficient in vitro lymphocyte population tracking and fate prediction using automation and manual review. PLoS One 2014; 9:e83251. [PMID: 24404133 PMCID: PMC3880260 DOI: 10.1371/journal.pone.0083251] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 10/31/2013] [Indexed: 01/26/2023] Open
Abstract
Interest in cell heterogeneity and differentiation has recently led to increased use of time-lapse microscopy. Previous studies have shown that cell fate may be determined well in advance of the event. We used a mixture of automation and manual review of time-lapse live cell imaging to track the positions, contours, divisions, deaths and lineage of 44 B-lymphocyte founders and their 631 progeny in vitro over a period of 108 hours. Using this data to train a Support Vector Machine classifier, we were retrospectively able to predict the fates of individual lymphocytes with more than 90% accuracy, using only time-lapse imaging captured prior to mitosis or death of 90% of all cells. The motivation for this paper is to explore the impact of labour-efficient assistive software tools that allow larger and more ambitious live-cell time-lapse microscopy studies. After training on this data, we show that machine learning methods can be used for realtime prediction of individual cell fates. These techniques could lead to realtime cell culture segregation for purposes such as phenotype screening. We were able to produce a large volume of data with less effort than previously reported, due to the image processing, computer vision, tracking and human-computer interaction tools used. We describe the workflow of the software-assisted experiments and the graphical interfaces that were needed. To validate our results we used our methods to reproduce a variety of published data about lymphocyte populations and behaviour. We also make all our data publicly available, including a large quantity of lymphocyte spatio-temporal dynamics and related lineage information.
Collapse
Affiliation(s)
- Rajib Chakravorty
- National ICT Australia, Dept. of Electrical & Electronic Engineering, the University of Melbourne, Melbourne, Victoria, Australia
- * E-mail:
| | - David Rawlinson
- National ICT Australia, Dept. of Electrical & Electronic Engineering, the University of Melbourne, Melbourne, Victoria, Australia
| | - Alan Zhang
- National ICT Australia, Dept. of Electrical & Electronic Engineering, the University of Melbourne, Melbourne, Victoria, Australia
| | - John Markham
- National ICT Australia, Dept. of Electrical & Electronic Engineering, the University of Melbourne, Melbourne, Victoria, Australia
| | - Mark R. Dowling
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria, Australia
- Department of Medical Biology, the University of Melbourne, Melbourne, Victoria, Australia
| | - Cameron Wellard
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria, Australia
- Department of Medical Biology, the University of Melbourne, Melbourne, Victoria, Australia
| | - Jie H. S. Zhou
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria, Australia
- Department of Medical Biology, the University of Melbourne, Melbourne, Victoria, Australia
| | - Philip D. Hodgkin
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria, Australia
- Department of Medical Biology, the University of Melbourne, Melbourne, Victoria, Australia
| |
Collapse
|
19
|
Dowling MR, Josefsson EC, Henley KJ, Kile BT, Hodgkin PD. A model for studying the hemostatic consumption or destruction of platelets. PLoS One 2013; 8:e57783. [PMID: 23505441 PMCID: PMC3591423 DOI: 10.1371/journal.pone.0057783] [Citation(s) in RCA: 5] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 01/25/2013] [Indexed: 11/18/2022] Open
Abstract
A fundamental issue in understanding homeostasis of the hematopoietic system is to what extent intrinsic and extrinsic factors regulate cell fate. We recently revisited this issue for the case of blood platelets and concluded that platelet life span is largely regulated by internal factors, in contrast to the long-held view that accumulated damage from the environment triggers clearance. However, it is known that in humans there is an ongoing fixed requirement for platelets to maintain hemostasis and prevent bleeding; hence a proportion of platelets may be consumed in such processes before the end of their natural life span. Whether it is possible to detect this random loss of platelets in normal individuals at steady-state is unknown. To address this question, we have developed a mathematical model that independently incorporates age-independent random loss and age-dependent natural senescent clearance. By fitting to population survival curves, we illustrate the application of the model in quantifying the fixed requirement for platelets to maintain hemostasis in mice, and discuss the relationship with previous work in humans. Our results suggest a higher requirement for platelets in mice than in humans, however experimental uncertainty in the data limits our ability to constrain this quantity. We then explored the relationship between experimental uncertainty and parameter constraint using simulated data. We conclude that in order to provide useful constraint on the random loss fraction the standard error in the mean of the data must be reduced substantially, either through improving experimental uncertainty or increasing the number of experimental replicates to impractical levels. Finally we find that parameter constraint is improved at higher values of the random loss fraction; thus the model find utility in situations where the random loss fraction is expected to be high, for example during active bleeding or some types of thrombocytopenia.
Collapse
Affiliation(s)
- Mark R Dowling
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
| | | | | | | | | |
Collapse
|
20
|
Riddy DM, Stamp C, Sykes DA, Charlton SJ, Dowling MR. Reassessment of the pharmacology of Sphingosine-1-phosphate S1P3 receptor ligands using the DiscoveRx PathHunter™ and Ca2+ release functional assays. Br J Pharmacol 2013; 167:868-80. [PMID: 22577868 DOI: 10.1111/j.1476-5381.2012.02032.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND AND PURPOSE DiscoverRx's PathHunter™ assay measures GPCR agonist potency, via the recruitment of β-arrestin, independent of the subtype of G(α) protein activated. This assay is frequently used in drug discovery although little is known about the agonist pharmacology generated. Here we have compared agonist potency, efficacy and affinity values obtained in PathHunter™ assays with those from more established radioligand binding and functional techniques. EXPERIMENTAL APPROACH Using cells expressing the human sphingosine-1-phosphate S1P(3) receptor at four different densities, we compared pharmacological affinity and efficacy values of four structurally distinct ligands - FTY720-P, VPC24191, CYM5442 and the endogenous agonist S1P - obtained from competition binding, functional Ca(2+) release and PathHunter™ assays. KEY RESULTS The pK(i) values for S1P were significantly different (9.34 ± 0.10 and 8.92 ± 0.15) in clones expressing different receptor levels using the binding assay. In the PathHunter™ and Ca(2+) assays, S1P and CYM5442 were full agonists, FTY720-P was a partial agonist, while the efficacy of VPC24191 could not be detected in PathHunter™ assays. VPC23019, previously described as a S1P(1/3) receptor antagonist, behaved as an S1P(3) receptor partial agonist in the Ca(2+) release assay. CONCLUSIONS AND IMPLICATIONS Comparison of data from the PathHunter™ assay with binding and functional Ca(2+) assays suggest that PathHunter™ assays measured a different agonist-bound receptor conformation. While this assay has great utility in drug discovery, care must be taken as high-efficacy, low-affinity agonist compounds would not be detected. Therefore highly amplified, more traditional assays are necessary to identify agonists with low efficacy.
Collapse
Affiliation(s)
- D M Riddy
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham, West Sussex, UK
| | | | | | | | | |
Collapse
|
21
|
|
22
|
Andrews RK, Aster RH, Atkinson BT, Barnard MR, Bavry AA, Bayer AS, Beaulieu LM, Berndt MC, Berny-Lang MA, Bhatt DL, Bizzaro N, Bledzka K, Bouchard BA, Brass LF, Bray PF, Briggs C, Bussel JB, Cattaneo M, Chakravorty S, Chong BH, Clemetson J, Clemetson KJ, Coller BS, Covic L, Davì G, del Zoppo GJ, Dowling MR, Dubois C, Eisert WG, Evangelista V, Flaumenhaft R, Freedman JE, Freedman J, Frelinger AL, Furie BC, Furie B, Gardiner C, Gawaz M, Geisler T, Greinacher A, Gurbel PA, Harrison P, Hartwig JH, Hayward CP, Hughes CE, Ikeda Y, Israels SJ, Italiano JE, Jackson S, Jain S, Jones CI, Josefsson EC, Kaplan C, Kile BT, Kimura Y, Klement GL, Kolandaivelu K, Kuliopulos A, Kuter DJ, Lambert MP, Langer HF, Lebois M, Levin J, Lordkipanidzé M, Ma YQ, Mannucci PM, McCrae KR, Merrill-Skoloff G, Michelson AD, Moffat KA, Mutch NJ, Newman DK, Newman PE, Ni H, Nieuwland R, Ouwehand WH, Parsons J, Patrono C, Perrotta PL, Pesho MM, Plow EF, Politt AY, Poncz M, Poon MC, Provost P, Psaila B, Rao AK, Rinder HM, Roberts IA, Rondina MT, Ruggeri ZM, Santilli F, Schwertz H, Shai E, Silveira JR, Smith BR, Smith MC, Smyth SS, Snyder EL, Sobel M, Soranzo N, Stalker TJ, Sturk A, Sudo T, Sullivan S, Tantry US, Tefferi A, Tracy PB, Tsai HM, van der Pol E, Varon D, Vazzana N, Vieira-de-Abreu A, Wannemacher K, Ware J, Warkentin TE, Watson SP, Weyrich AS, White JG, Wilcox DA, Yeaman MR, Zhang P, Zhu L, Zimmerman GA. List of Contributors. Platelets 2013. [DOI: 10.1016/b978-0-12-387837-3.00072-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
23
|
Sykes DA, Dowling MR, Leighton-Davies J, Kent TC, Fawcett L, Renard E, Trifilieff A, Charlton SJ. The Influence of Receptor Kinetics on the Onset and Duration of Action and the Therapeutic Index of NVA237 and Tiotropium. J Pharmacol Exp Ther 2012; 343:520-8. [DOI: 10.1124/jpet.112.194456] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
24
|
Sykes DA, Dowling MR, Charlton SJ. Measuring receptor target coverage: a radioligand competition binding protocol for assessing the association and dissociation rates of unlabeled compounds. ACTA ACUST UNITED AC 2012; Chapter 9:Unit 9.14. [PMID: 22294377 DOI: 10.1002/0471141755.ph0914s50] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The kinetics of the ligand-receptor interaction is an important feature in lead optimization for new drug candidates. The protocol described in this unit is a kinetic radioligand competition binding assay that makes possible the determination of both the association and dissociation rates of unlabeled receptor ligands.
Collapse
Affiliation(s)
- David A Sykes
- Novartis Institutes for Biomedical Research, Horsham, West Sussex, United Kingdom
| | | | | |
Collapse
|
25
|
Josefsson EC, James C, Henley KJ, Debrincat MA, Rogers KL, Dowling MR, White MJ, Kruse EA, Lane RM, Ellis S, Nurden P, Mason KD, O'Reilly LA, Roberts AW, Metcalf D, Huang DC, Kile BT. Megakaryocytes possess a functional intrinsic apoptosis pathway that must be restrained to survive and produce platelets. J Biophys Biochem Cytol 2011. [DOI: 10.1083/jcb1946oia12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
26
|
Josefsson EC, James C, Henley KJ, Debrincat MA, Rogers KL, Dowling MR, White MJ, Kruse EA, Lane RM, Ellis S, Nurden P, Mason KD, O'Reilly LA, Roberts AW, Metcalf D, Huang DCS, Kile BT. Megakaryocytes possess a functional intrinsic apoptosis pathway that must be restrained to survive and produce platelets. ACTA ACUST UNITED AC 2011; 208:2017-31. [PMID: 21911424 PMCID: PMC3182050 DOI: 10.1084/jem.20110750] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Deletion of Bak and Bax, the effectors of mitochondrial apoptosis, does not affect platelet production, however, loss of prosurvival Bcl-xL results in megakaryocyte apoptosis and failure of platelet shedding. It is believed that megakaryocytes undergo a specialized form of apoptosis to shed platelets. Conversely, a range of pathophysiological insults, including chemotherapy, are thought to cause thrombocytopenia by inducing the apoptotic death of megakaryocytes and their progenitors. To resolve this paradox, we generated mice with hematopoietic- or megakaryocyte-specific deletions of the essential mediators of apoptosis, Bak and Bax. We found that platelet production was unperturbed. In stark contrast, deletion of the prosurvival protein Bcl-xL resulted in megakaryocyte apoptosis and a failure of platelet shedding. This could be rescued by deletion of Bak and Bax. We examined the effect on megakaryocytes of three agents that activate the intrinsic apoptosis pathway in other cell types: etoposide, staurosporine, and the BH3 mimetic ABT-737. All three triggered mitochondrial damage, caspase activation, and cell death. Deletion of Bak and Bax rendered megakaryocytes resistant to etoposide and ABT-737. In vivo, mice with a Bak−/− Bax−/− hematopoietic system were protected against thrombocytopenia induced by the chemotherapeutic agent carboplatin. Thus, megakaryocytes do not activate the intrinsic pathway to generate platelets; rather, the opposite is true: they must restrain it to survive and progress safely through proplatelet formation and platelet shedding.
Collapse
Affiliation(s)
- Emma C Josefsson
- Molecular Medicine Division, Cancer and Hematology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Abstract
Cell tracking is a key task in the high-throughput quantitative study of important biological processes, such as immune system regulation and neurogenesis. Variability in cell density and dynamics in different videos, hampers portability of existing trackers across videos. We address these potability challenges in order to develop a portable cell tracking algorithm. Our algorithm can handle noise in cell segmentation as well as divisions and deaths of cells. We also propose a parameter-free variation of our tracker. In the tracker, we employ a novel method for recovering the distribution of cell displacements. Further, we present a mathematically justified procedure for determining the gating distance in relation to tracking performance. For the range of real videos tested, our tracker correctly recovers on average 96% of cell moves, and outperforms an advanced probabilistic tracker when the cell detection quality is high. The scalability of our tracker was tested on synthetic videos with up to 200 cells per frame. For more challenging tracking conditions, we propose a novel semi-automated framework that can increase the ratio of correctly recovered tracks by 12%, through selective manual inspection of only 10% of all frames in a video.
Collapse
Affiliation(s)
- A Kan
- Victoria Research Laboratory, National ICT Australia (NICTA), Department of Computer Science and Software Engineering, University of Melbourne, VIC, Australia.
| | | | | | | | | | | |
Collapse
|
28
|
Dowling MR, Hodgkin PD. Why does the thymus involute? A selection-based hypothesis. Trends Immunol 2009; 30:295-300. [PMID: 19540805 DOI: 10.1016/j.it.2009.04.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 03/30/2009] [Accepted: 04/07/2009] [Indexed: 02/04/2023]
Abstract
Thymic involution remains a fundamental mystery in immunology. Here we present an argument that this seemingly counterproductive behavior may have evolved to allow for peripheral selection of a T-cell repertoire during young-adult life, optimized for fighting infections and avoiding reaction to self. Age-associated decline in immune function may be viewed as an unfortunate side effect of this selective process. Thus, the key to understanding thymic involution might lie in a more quantitative understanding of T-cell homeostasis in the periphery.
Collapse
Affiliation(s)
- Mark R Dowling
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3050, Australia
| | | |
Collapse
|
29
|
Sykes DA, Dowling MR, Charlton SJ. Exploring the mechanism of agonist efficacy: a relationship between efficacy and agonist dissociation rate at the muscarinic M3 receptor. Mol Pharmacol 2009; 76:543-51. [PMID: 19498041 DOI: 10.1124/mol.108.054452] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although there are several empirical approaches that enable the comparison of relative agonist efficacy, the molecular basis that underlies differences in the ability of G protein-coupled receptor agonists to elicit a response is still largely unexplained. Several models have been described that incorporate the kinetics of receptor-mediated initiation of the G protein cycle, but these have not directly addressed the influence of agonist-binding kinetics. To test this, we investigated the relationship between the efficacy of seven M(3) muscarinic receptor agonists and their rate of dissociation (k(off)) from the M(3) receptor. The association and dissociation rate constants of the agonists were determined using a l-[N-methyl]-[(3)H]scopolamine methyl chloride competition binding assay in the presence of GTP. The agonists displayed a range of association and dissociation rates. Relative agonist efficacy was measured at two points after M(3) receptor activation: the stimulation of guanosine 5'-O-(3-[(35)S]thio)triphosphate binding to G alpha subunits, and the subsequent increase in intracellular calcium levels. These experiments revealed a range of intrinsic efficacy, from the low-efficacy pilocarpine and oxotremorine to high-efficacy acetylcholine. There was no relationship between agonist efficacy and the equilibrium binding affinity of each agonist (K(d)). When efficacy was compared with the dissociation rate constant, however, the two were highly correlated, suggesting a relationship between the duration of agonist binding at the receptor and the intrinsic efficacy. These data suggest that kinetic models incorporating the mean lifetime of specific complexes will be required to fully explain the nature of agonist efficacy.
Collapse
Affiliation(s)
- David A Sykes
- Novartis Institutes for Biomedical Sciences, Wimblehurst Road, Horsham, West Sussex, UK.
| | | | | |
Collapse
|
30
|
Abstract
In cell lifespan studies the exponential nature of cell survival curves is often interpreted as showing the rate of death is independent of the age of the cells within the population. Here we present an alternative model where cells that die are replaced and the age and lifespan of the population pool is monitored until a steady state is reached. In our model newly generated individual cells are given a determined lifespan drawn from a number of known distributions including the lognormal, which is frequently found in nature. For lognormal lifespans the analytic steady-state survival curve obtained can be well-fit by a single or double exponential, depending on the mean and standard deviation. Thus, experimental evidence for exponential lifespans of one and/or two populations cannot be taken as definitive evidence for time and age independence of cell survival. A related model for a dividing population in steady state is also developed. We propose that the common adoption of age-independent, constant rates of change in biological modelling may be responsible for significant errors, both of interpretation and of mathematical deduction. We suggest that additional mathematical and experimental methods must be used to resolve the relationship between time and behavioural changes by cells that are predominantly unsynchronized.
Collapse
Affiliation(s)
- Mark R Dowling
- The Walter and Eliza Hall Institute of Medical Research1G Royal Parade, Parkville, Victoria 3050, Australia
- School of Physical Sciences, The University of QueenslandQueensland 4072, Australia
| | - Dejan Milutinović
- Theoretical Biology, Utrecht UniversityPadualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Philip D Hodgkin
- The Walter and Eliza Hall Institute of Medical Research1G Royal Parade, Parkville, Victoria 3050, Australia
- Author for correspondence ()
| |
Collapse
|
31
|
Dowling MR, Charlton SJ. Quantifying the association and dissociation rates of unlabelled antagonists at the muscarinic M3 receptor. Br J Pharmacol 2006; 148:927-37. [PMID: 16847442 PMCID: PMC1751918 DOI: 10.1038/sj.bjp.0706819] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Slow receptor dissociation kinetics has been implicated in the long clinical duration of action of the muscarinic receptor antagonist tiotropium. However, despite the potential benefits of new drugs with slow dissociation kinetics, the rate parameters of new compounds are seldom measured due to technical difficulties and financial implications associated with radiolabeling multiple ligands. Here we describe the development and optimisation of a medium throughput assay which is capable of measuring the kinetic parameters of novel, unlabelled compounds. Radioligand binding studies were performed with membranes derived from CHO cells recombinantly expressing the human M(3) muscarinic receptor.Initial characterisation of the radioligand [(3)H]-NMS yielded on and off rates of 4.1+/-0.2 x 10(8) M(-1) min(-1) and 0.015+/-0.0005 min(-1), respectively. The specific binding of [(3)H]-NMS was measured over time in the presence and absence of several concentrations of unlabelled competitor compounds. These data were analysed using a competition kinetic model to provide on and off rates for the unlabelled competitor. Comparison of the kinetically derived Kd (k(off)/k(on)) with K(i) values generated at equilibrium showed an excellent correlation (r(2)=0.99), providing good validation of the method. The on and off rates were also used in theoretical computer simulations to successfully predict the effect of incubation time on apparent IC(50) values. This study demonstrates that a medium-throughput competition kinetic binding assay can be used to determine accurate on and off rates of unlabelled compounds, providing the opportunity to optimise for kinetic parameters early in the drug discovery process.
Collapse
Affiliation(s)
- Mark R Dowling
- Novartis Institutes for Biomedical Research, Wimblehurst Road, Horsham, West Sussex RH12 5AB.
| | | |
Collapse
|
32
|
Abstract
Quantum computers hold great promise for solving interesting computational problems, but it remains a challenge to find efficient quantum circuits that can perform these complicated tasks. Here we show that finding optimal quantum circuits is essentially equivalent to finding the shortest path between two points in a certain curved geometry. By recasting the problem of finding quantum circuits as a geometric problem, we open up the possibility of using the mathematical techniques of Riemannian geometry to suggest new quantum algorithms or to prove limitations on the power of quantum computers.
Collapse
Affiliation(s)
- Michael A Nielsen
- School of Physical Sciences, University of Queensland, Queensland 4072, Australia.
| | | | | | | |
Collapse
|
33
|
Dowling MR, Willets JM, Budd DC, Charlton SJ, Nahorski SR, Challiss RAJ. A Single Point Mutation (N514Y) in the Human M3Muscarinic Acetylcholine Receptor Reveals Differences in the Properties of Antagonists: Evidence for Differential Inverse Agonism. J Pharmacol Exp Ther 2006; 317:1134-42. [PMID: 16489127 DOI: 10.1124/jpet.106.101246] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [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: 11/22/2022] Open
Abstract
A single asparagine-to-tyrosine point mutation in the human M muscarinic acetylcholine (mACh) receptor at residue 514 (N514Y) resulted in a marked increase (approximately 300%) in agonist-independent [3H]inositol phosphate ([3H]IPx) accumulation compared with the response observed for the wild-type (WT) receptor. All the antagonists tested were able to inhibit both the WT-M3 and (N514Y)M3 mACh receptor-mediated basal [3H]IPx accumulation in a concentration-dependent manner. However, significant differences in both potency and binding affinity were only seen for those antagonists that possess greater receptor affinity. Despite being transfected with equivalent amounts of cDNA, cells expressed the (N514Y)M3 mACh receptor at levels that were only 25 to 30% of those seen for the WT receptor. Differences in the ability of chronic antagonist exposure to up-regulate (N514Y)M3 mACh receptor expression levels were also seen, with 4-diphenylacetoxy-N-methylpiperidine (4-DAMP) producing only 50% of the receptor up-regulation produced by atropine or pirenzepine. Basal phosphorylation of the (N514Y)M3 mACh receptor was approximately 100% greater than that seen for the WT-M3 receptor. The ability of antagonists to decrease basal (N514Y)M3 mACh receptor phosphorylation revealed differences in inverse-agonist efficacy. Atropine, 4-DAMP, and pirenzepine all reduced basal phosphorylation to similar levels, whereas methoctramine, a full inverse agonist with respect to reducing agonist-independent [3H]IPx accumulation, produced no significant attenuation of basal receptor phosphorylation. This study shows that mACh receptor inverse agonists can exhibit differential signaling profiles, which are dependent on the specific pathway investigated, and therefore provides evidence that the molecular mechanism of inverse agonism is likely to be more complex than the stabilization of a single inactive receptor conformation.
Collapse
Affiliation(s)
- Mark R Dowling
- Department of Cell Physiology and Pharmacology, Maurice Shock Medical Sciences Building, University of Leicester, University Road, Leicester, LE1 9HN, UK
| | | | | | | | | | | |
Collapse
|
34
|
Battram C, Charlton SJ, Cuenoud B, Dowling MR, Fairhurst RA, Farr D, Fozard JR, Leighton-Davies JR, Lewis CA, McEvoy L, Turner RJ, Trifilieff A. In Vitro and in Vivo Pharmacological Characterization of 5-[(R)-2-(5,6-Diethyl-indan-2-ylamino)-1-hydroxy-ethyl]-8-hydroxy-1H-quinolin-2-one (Indacaterol), a Novel Inhaled β2 Adrenoceptor Agonist with a 24-h Duration of Action. J Pharmacol Exp Ther 2006; 317:762-70. [PMID: 16434564 DOI: 10.1124/jpet.105.098251] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Here, we describe the preclinical pharmacological profile of 5-[(R)-2-(5,6-diethyl-indan-2-ylamino)-1-hydroxy-ethyl]-8-hydroxy-1H-quinolin-2-one (indacaterol), a novel, chirally pure inhaled beta(2) adrenoceptor agonist, in comparison with marketed drugs. Indacaterol is close to a full agonist at the human beta(2) adrenoceptor (E(max) = 73 +/- 1% of the maximal effect of isoprenaline; pEC(50) = 8.06 +/- 0.02), whereas salmeterol displays only partial efficacy (38 +/- 1%). The functional selectivity profile of indacaterol over beta(1) human adrenoceptors is similar to that of formoterol, whereas its beta(3) adrenoceptor selectivity profile is similar to that of formoterol and salbutamol. In isolated superfused guinea pig trachea, indacaterol has a fast onset of action (30 +/- 4 min) similar to formoterol and salbutamol, and a long duration of action (529 +/- 99 min) comparable with salmeterol. In the conscious guinea pig, when given intratracheally as a dry powder, indacaterol inhibits 5-hydroxytryptamine-induced bronchoconstriction for at least 24 h, whereas salmeterol, formoterol, and salbutamol have durations of action of 12, 4, and 2 h, respectively. When given via nebulization to anesthetized rhesus monkeys, all of the compounds dose-dependently inhibit methacholine-induced bronchoconstriction, although indacaterol produces the most prolonged bronchoprotective effect and induces the lowest increase in heart rate for a similar degree of antibronchoconstrictor activity. In conclusion, the preclinical profile of indacaterol suggests that this compound has a superior duration of action compatible with once-daily dosing in human, together with a fast onset of action and an improved cardiovascular safety profile over marketed inhaled beta(2) adrenoceptor agonists.
Collapse
Affiliation(s)
- Cliff Battram
- Novartis Institutes for BioMedical Research, Respiratory Diseases Area, Horsham, United Kingdom
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Mistry R, Dowling MR, Challiss RAJ. An investigation of whether agonist-selective receptor conformations occur with respect to M2 and M4 muscarinic acetylcholine receptor signalling via Gi/o and Gs proteins. Br J Pharmacol 2005; 144:566-75. [PMID: 15655507 PMCID: PMC1576035 DOI: 10.1038/sj.bjp.0706090] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. A range of muscarinic acetylcholine (mACh) receptor agonists (methacholine (MCh), oxotremorine-M (OXO-M), oxotremorine (OXO), arecoline (AREC), bethanechol (BETH), pilocarpine (PILO)) have been investigated with respect to their binding to, and activation of, M(2) and M(4) mACh receptors, recombinantly expressed in Chinese hamster ovary cells, to explore the possibility that these agonists may differentially affect mACh receptor-G(i/o) and -G(s) coupling. 2. M(2)/M(4) mACh receptor coupling to the adenylyl cyclase/cyclic AMP signalling pathway has been explored in intact cells. G(i/o)-mediated negative coupling to adenylyl cyclase was explored functionally by assessing the ability of the mACh receptor agonists to inhibit forskolin-stimulated enzymic activity. Following pertussis toxin treatment (100 ng ml(-1), 18-20 h) to inactivate G(i/o) proteins, each agonist caused a G(s)-mediated enhancement of forskolin-stimulated adenylyl cyclase activity. 3. At both M(2) and M(4) mACh receptors, all agonists tested were more potent in mediating G(i/o)- versus G(s)-coupled responses. This difference (determined as the pIC(50) (G(i/o) coupling) minus pEC(50) (G(s) coupling) value) was greatest for AREC (65-75-fold) and least for BETH and PILO (</=10-fold). 4. Using apparent binding affinities (pK(B)), and potency (EC(50)/IC(50)) and responsiveness (E(max)/I(max)) estimates, relative efficacy (e(rel)) values for each agonist with respect to M(2) and M(4) mACh receptor coupling to G(i/o)- and G(s)-mediated signalling were also calculated. While the e(rel) values obtained for MCh and OXO-M in CHO-m2 cells were similar, OXO-M behaved as a 'super-agonist' at the M(4) mACh receptor giving greater e(rel) values for both G(i/o) and G(s) coupling relative to MCh. 5. The experimental data indicate that while interesting differences between agonists with respect to M(2)/M(4) mACh receptor activation and receptor-G(i/o) and -G(s) coupling can be discerned, no clear examples of agonist trafficking of signal have emerged.
Collapse
Affiliation(s)
- Rajendra Mistry
- Department of Cell Physiology and Pharmacology, University of Leicester, Maurice Shock Medical Sciences Building, University Road, Leicester LE1 9HN
| | - Mark R Dowling
- Department of Cell Physiology and Pharmacology, University of Leicester, Maurice Shock Medical Sciences Building, University Road, Leicester LE1 9HN
| | - R A John Challiss
- Department of Cell Physiology and Pharmacology, University of Leicester, Maurice Shock Medical Sciences Building, University Road, Leicester LE1 9HN
- Author for correspondence:
| |
Collapse
|
36
|
Abstract
The calculation of quantum dynamics is currently a central issue in theoretical physics, with diverse applications ranging from ultracold atomic Bose-Einstein condensates to condensed matter, biology, and even astrophysics. Here we demonstrate a conceptually simple method of determining the regime of validity of stochastic simulations of unitary quantum dynamics by employing a time-reversal test. We apply this test to a simulation of the evolution of a quantum anharmonic oscillator with up to 6.022x10(23) (Avogadro's number) of particles. This system is realizable as a Bose-Einstein condensate in an optical lattice, for which the time-reversal procedure could be implemented experimentally.
Collapse
Affiliation(s)
- Mark R Dowling
- ARC Centre of Excellence for Quantum-Atom Optics, School of Physical Sciences, University of Queensland, Brisbane, QLD 4072, Australia
| | | | | | | |
Collapse
|
37
|
Dowling MR, Nahorski SR, Challiss RAJ. Measurement of agonist-stimulated [35S]GTPgammaS binding to assess total G-protein and Galpha-subtype-specific activation by G-protein-coupled receptors. Methods Mol Biol 2004; 259:197-206. [PMID: 15250494 DOI: 10.1385/1-59259-754-8:197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
On activation, G-protein-coupled receptors (GPCRs) exert many of their cellular actions through promotion of guanine nucleotide exchange on the Galpha-subunit of heterotrimeric G-proteins to release free Galpha-GTP and betagamma-subunits. In membrane preparations, GTP can be substituted by 35S-labeled guanosine 5'-O-(3-thio)triphosphate ([35S]GTPgammaS) and on agonist stimulation a stable [35S]GTPgammaS-Galpha complex will form and accumulate. Separation of 35S-bound GTPgammaS-Galpha complexes from free [35S]GTPgammaS allows differences between basal and agonist-stimulated rates of [35S]GTPgammaS-Galpha complex formation to be used to obtain pharmacological information on receptor-G-protein information transfer. Further, by releasing Galpha-subunits into solution following the [35S]GTPgammaS binding step, Galpha-subunit-specific antibodies can be used to investigate the Galpha-protein subpopulations activated by receptors by immunoprecipitation of [35S]GTPgammaS-Galpha complexes and quantification by scintillation counting. Here we describe a total [35S]GTPgammaS binding assay and a modification of this method that incorporates a Galpha-specific immunoprecipitation step.
Collapse
Affiliation(s)
- Mark R Dowling
- Novartis Horsham Research Center, West Sussex, United Kingdom
| | | | | |
Collapse
|