Jonathan Scott1, Graham J Harris1, Emma M Pinder1, James G Macfarlane1, Thomas P Hellyer1, Anthony J Rostron1, Andrew Conway Morris2, David R Thickett3, Gavin D Perkins4, Daniel F McAuley5, John D Widdrington1, Sarah Wiscombe1, Simon V Baudouin6, Alistair I Roy7, Vanessa C Linnett8, Stephen E Wright9, Marie-Hélène Ruchaud-Sparagano1, A John Simpson10. 1. Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom. 2. Division of Anaesthesia, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom. 3. Centre for Translational Inflammation Research, University of Birmingham, Queen Elizabeth Hospital, Birmingham, United Kingdom. 4. Warwick Medical School Clinical Trials Unit and Heart of England Foundation Trust, University of Warwick, Coventry, United Kingdom. 5. Centre for Infection and Immunity, Health Sciences Building, Queen's University Belfast, Belfast, United Kingdom; Regional Intensive Care Unit, Royal Victoria Hospital, Belfast, United Kingdom. 6. Department of Anaesthetics, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom. 7. Integrated Critical Care Unit, Sunderland Royal Hospital, Sunderland, United Kingdom. 8. Intensive Care Unit, Queen Elizabeth Hospital, Gateshead, United Kingdom. 9. Intensive Care Unit, Freeman Hospital, Newcastle upon Tyne, United Kingdom. 10. Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom. Electronic address: j.simpson@ncl.ac.uk.
Abstract
BACKGROUND: Neutrophils play a role in the pathogenesis of asthma, chronic obstructive pulmonary disease, and pulmonary infection. Impaired neutrophil phagocytosis predicts hospital-acquired infection. Despite this, remarkably few neutrophil-specific treatments exist. OBJECTIVES: We sought to identify novel pathways for the restoration of effective neutrophil phagocytosis and to activate such pathways effectively in neutrophils from patients with impaired neutrophil phagocytosis. METHODS: Blood neutrophils were isolated from healthy volunteers and patients with impaired neutrophil function. In healthy neutrophils phagocytic impairment was induced experimentally by using β2-agonists. Inhibitors and activators of cyclic AMP (cAMP)-dependent pathways were used to assess the influence on neutrophil phagocytosis in vitro. RESULTS: β2-Agonists and corticosteroids inhibited neutrophil phagocytosis. Impairment of neutrophil phagocytosis by β2-agonists was associated with significantly reduced RhoA activity. Inhibition of protein kinase A (PKA) restored phagocytosis and RhoA activity, suggesting that cAMP signals through PKA to drive phagocytic impairment. However, cAMP can signal through effectors other than PKA, such as exchange protein directly activated by cyclic AMP (EPAC). An EPAC-activating analog of cAMP (8CPT-2Me-cAMP) reversed neutrophil dysfunction induced by β2-agonists or corticosteroids but did not increase RhoA activity. 8CPT-2Me-cAMP reversed phagocytic impairment induced by Rho kinase inhibition but was ineffective in the presence of Rap-1 GTPase inhibitors. 8CPT-2Me-cAMP restored function to neutrophils from patients with known acquired impairment of neutrophil phagocytosis. CONCLUSIONS: EPAC activation consistently reverses clinical and experimental impairment of neutrophil phagocytosis. EPAC signals through Rap-1 and bypasses RhoA. EPAC activation represents a novel potential means by which to reverse impaired neutrophil phagocytosis.
BACKGROUND: Neutrophils play a role in the pathogenesis of asthma, chronic obstructive pulmonary disease, and pulmonary infection. Impaired neutrophil phagocytosis predicts hospital-acquired infection. Despite this, remarkably few neutrophil-specific treatments exist. OBJECTIVES: We sought to identify novel pathways for the restoration of effective neutrophil phagocytosis and to activate such pathways effectively in neutrophils from patients with impaired neutrophil phagocytosis. METHODS: Blood neutrophils were isolated from healthy volunteers and patients with impaired neutrophil function. In healthy neutrophils phagocytic impairment was induced experimentally by using β2-agonists. Inhibitors and activators of cyclic AMP (cAMP)-dependent pathways were used to assess the influence on neutrophil phagocytosis in vitro. RESULTS: β2-Agonists and corticosteroids inhibited neutrophil phagocytosis. Impairment of neutrophil phagocytosis by β2-agonists was associated with significantly reduced RhoA activity. Inhibition of protein kinase A (PKA) restored phagocytosis and RhoA activity, suggesting that cAMP signals through PKA to drive phagocytic impairment. However, cAMP can signal through effectors other than PKA, such as exchange protein directly activated by cyclic AMP (EPAC). An EPAC-activating analog of cAMP (8CPT-2Me-cAMP) reversed neutrophil dysfunction induced by β2-agonists or corticosteroids but did not increase RhoA activity. 8CPT-2Me-cAMP reversed phagocytic impairment induced by Rho kinase inhibition but was ineffective in the presence of Rap-1 GTPase inhibitors. 8CPT-2Me-cAMP restored function to neutrophils from patients with known acquired impairment of neutrophil phagocytosis. CONCLUSIONS:EPAC activation consistently reverses clinical and experimental impairment of neutrophil phagocytosis. EPAC signals through Rap-1 and bypasses RhoA. EPAC activation represents a novel potential means by which to reverse impaired neutrophil phagocytosis.
Authors: Anders S I Andreasson; Lee A Borthwick; Colin Gillespie; Kasim Jiwa; Jonathan Scott; Paul Henderson; Jonny Mayes; Rosalba Romano; Marius Roman; Simi Ali; James E Fildes; Nandor Marczin; John H Dark; Andrew J Fisher Journal: J Heart Lung Transplant Date: 2017-05-12 Impact factor: 10.247
Authors: Yu Zhang; Yanwen Wang; Joseph Yanni; Mohammed Anwar Qureshi; Sunil Jit R J Logantha; Sarah Kassab; Mark R Boyett; Natalie J Gardiner; Hong Sun; Frank Christopher Howarth; Halina Dobrzynski Journal: Front Physiol Date: 2019-07-08 Impact factor: 4.566
Authors: Alexander Jt Wood; Arlette M Vassallo; Marie-Hélène Ruchaud-Sparagano; Jonathan Scott; Carmelo Zinnato; Carmen Gonzalez-Tejedo; Kamal Kishore; Clive S D'Santos; A John Simpson; David K Menon; Charlotte Summers; Edwin R Chilvers; Klaus Okkenhaug; Andrew Conway Morris Journal: JCI Insight Date: 2020-08-06