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Yeoh WJ, Krebs P. SHIP1 and its role for innate immune regulation-Novel targets for immunotherapy. Eur J Immunol 2023; 53:e2350446. [PMID: 37742135 DOI: 10.1002/eji.202350446] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/03/2023] [Accepted: 09/21/2023] [Indexed: 09/25/2023]
Abstract
Phosphoinositide-3-kinase/AKT (PI3K/AKT) signaling plays key roles in the regulation of cellular activity in both health and disease. In immune cells, this PI3K/AKT pathway is critically regulated by the phosphoinositide phosphatase SHIP1, which has been reported to modulate the function of most immune subsets. In this review, we summarize our current knowledge of SHIP1 with a focus on innate immune cells, where we reflect on the most pertinent aspects described in the current literature. We also present several small-molecule agonists and antagonists of SHIP1 developed over the last two decades, which have led to improved outcomes in several preclinical models of disease. We outline these promising findings and put them in relation to human diseases with unmet medical needs, where we discuss the most attractive targets for immune therapies based on SHIP1 modulation.
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Affiliation(s)
- Wen Jie Yeoh
- Institute of Tissue Medicine and Pathology, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Philippe Krebs
- Institute of Tissue Medicine and Pathology, University of Bern, Bern, Switzerland
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2
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Samuels JD, Moore KA, Ennerfelt HE, Johnson AM, Walsh AE, Price RJ, Lukens JR. The Alzheimer's disease risk factor INPP5D restricts neuroprotective microglial responses in amyloid beta-mediated pathology. Alzheimers Dement 2023; 19:4908-4921. [PMID: 37061460 PMCID: PMC10576836 DOI: 10.1002/alz.13089] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/07/2023] [Accepted: 02/12/2023] [Indexed: 04/17/2023]
Abstract
INTRODUCTION Mutations in INPP5D, which encodes for the SH2-domain-containing inositol phosphatase SHIP-1, have recently been linked to an increased risk of developing late-onset Alzheimer's disease. While INPP5D expression is almost exclusively restricted to microglia in the brain, little is known regarding how SHIP-1 affects neurobiology or neurodegenerative disease pathogenesis. METHODS We generated and investigated 5xFAD Inpp5dfl/fl Cx3cr1Ert2Cre mice to ascertain the function of microglial SHIP-1 signaling in response to amyloid beta (Aβ)-mediated pathology. RESULTS SHIP-1 deletion in microglia led to substantially enhanced recruitment of microglia to Aβ plaques, altered microglial gene expression, and marked improvements in neuronal health. Further, SHIP-1 loss enhanced microglial plaque containment and Aβ engulfment when compared to microglia from Cre-negative 5xFAD Inpp5dfl/fl littermate controls. DISCUSSION These results define SHIP-1 as a pivotal regulator of microglial responses during Aβ-driven neurological disease and suggest that targeting SHIP-1 may offer a promising strategy to treat Alzheimer's disease. HIGHLIGHTS Inpp5d deficiency in microglia increases plaque-associated microglia numbers. Loss of Inpp5d induces activation and phagocytosis transcriptional pathways. Plaque encapsulation and engulfment by microglia are enhanced with Inpp5d deletion. Genetic ablation of Inpp5d protects against plaque-induced neuronal dystrophy.
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Affiliation(s)
- Joshua D Samuels
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia (UVA), Charlottesville, Virginia, USA
- Neuroscience Graduate Program, University of Virginia (UVA), Charlottesville, Virginia, USA
- Department of Biomedical Engineering, University of Virginia (UVA), Charlottesville, Virginia, USA
| | - Katelyn A Moore
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia (UVA), Charlottesville, Virginia, USA
| | - Hannah E Ennerfelt
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia (UVA), Charlottesville, Virginia, USA
- Neuroscience Graduate Program, University of Virginia (UVA), Charlottesville, Virginia, USA
| | - Alexis M Johnson
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia (UVA), Charlottesville, Virginia, USA
- Neuroscience Graduate Program, University of Virginia (UVA), Charlottesville, Virginia, USA
- Brain Immunology and Glia Training Program, University of Virginia (UVA), Charlottesville, Virginia, USA
| | - Adeline E Walsh
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia (UVA), Charlottesville, Virginia, USA
- Molecular Physiology and Biological Physics Graduate Program, University of Virginia (UVA), Charlottesville, Virginia, USA
- Biotechnology Training Program, University of Virginia (UVA), Charlottesville, Virginia, USA
| | - Richard J Price
- Neuroscience Graduate Program, University of Virginia (UVA), Charlottesville, Virginia, USA
- Department of Biomedical Engineering, University of Virginia (UVA), Charlottesville, Virginia, USA
- Biotechnology Training Program, University of Virginia (UVA), Charlottesville, Virginia, USA
| | - John R Lukens
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia (UVA), Charlottesville, Virginia, USA
- Neuroscience Graduate Program, University of Virginia (UVA), Charlottesville, Virginia, USA
- Brain Immunology and Glia Training Program, University of Virginia (UVA), Charlottesville, Virginia, USA
- Molecular Physiology and Biological Physics Graduate Program, University of Virginia (UVA), Charlottesville, Virginia, USA
- Biotechnology Training Program, University of Virginia (UVA), Charlottesville, Virginia, USA
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3
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Chu E, Mychasiuk R, Green TRF, Zamani A, Dill LK, Sharma R, Raftery AL, Tsantikos E, Hibbs ML, Semple BD. Regulation of microglial responses after pediatric traumatic brain injury: exploring the role of SHIP-1. Front Neurosci 2023; 17:1276495. [PMID: 37901420 PMCID: PMC10603304 DOI: 10.3389/fnins.2023.1276495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 09/18/2023] [Indexed: 10/31/2023] Open
Abstract
Introduction Severe traumatic brain injury (TBI) is the world's leading cause of permanent neurological disability in children. TBI-induced neurological deficits may be driven by neuroinflammation post-injury. Abnormal activity of SH2 domain-containing inositol 5' phosphatase-1 (SHIP-1) has been associated with dysregulated immunological responses, but the role of SHIP-1 in the brain remains unclear. The current study investigated the immunoregulatory role of SHIP-1 in a mouse model of moderate-severe pediatric TBI. Methods SHIP-1+/- and SHIP-1-/- mice underwent experimental TBI or sham surgery at post-natal day 21. Brain gene expression was examined across a time course, and immunofluorescence staining was evaluated to determine cellular immune responses, alongside peripheral serum cytokine levels by immunoassays. Brain tissue volume loss was measured using volumetric analysis, and behavior changes both acutely and chronically post-injury. Results Acutely, inflammatory gene expression was elevated in the injured cortex alongside increased IBA-1 expression and altered microglial morphology; but to a similar extent in SHIP-1-/- mice and littermate SHIP-1+/- control mice. Similarly, the infiltration and activation of CD68-positive macrophages, and reactivity of GFAP-positive astrocytes, was increased after TBI but comparable between genotypes. TBI increased anxiety-like behavior acutely, whereas SHIP-1 deficiency alone reduced general locomotor activity. Chronically, at 12-weeks post-TBI, SHIP-1-/- mice exhibited reduced body weight and increased circulating cytokines. Pro-inflammatory gene expression in the injured hippocampus was also elevated in SHIP-1-/- mice; however, GFAP immunoreactivity at the injury site in TBI mice was lower. TBI induced a comparable loss of cortical and hippocampal tissue in both genotypes, while SHIP-1-/- mice showed reduced general activity and impaired working memory, independent of TBI. Conclusion Together, evidence does not support SHIP-1 as an essential regulator of brain microglial morphology, brain immune responses, or the extent of tissue damage after moderate-severe pediatric TBI in mice. However, our data suggest that reduced SHIP-1 activity induces a greater inflammatory response in the hippocampus chronically post-TBI, warranting further investigation.
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Affiliation(s)
- Erskine Chu
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
- Department of Immunology, Monash University, Melbourne, VIC, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
- Deparment of Neurology, Alfred Health, Prahran, VIC, Australia
| | - Tabitha R. F. Green
- Department of Integrative Physiology, The University of Colorado Boulder, Boulder, CO, United States
| | - Akram Zamani
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
| | - Larissa K. Dill
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
- Alfred Health, Prahran, VIC, Australia
| | - Rishabh Sharma
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
| | - April L. Raftery
- Department of Immunology, Monash University, Melbourne, VIC, Australia
| | - Evelyn Tsantikos
- Department of Immunology, Monash University, Melbourne, VIC, Australia
| | - Margaret L. Hibbs
- Department of Immunology, Monash University, Melbourne, VIC, Australia
| | - Bridgette D. Semple
- Department of Neuroscience, Monash University, Melbourne, VIC, Australia
- Deparment of Neurology, Alfred Health, Prahran, VIC, Australia
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, Australia
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4
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Jeong JH, Choi EB, Jang HM, Ahn YJ, An HS, Lee JY, Park G, Jeong EA, Shin HJ, Lee J, Kim KE, Roh GS. The Role of SHIP1 on Apoptosis and Autophagy in the Adipose Tissue of Obese Mice. Int J Mol Sci 2020; 21:ijms21197225. [PMID: 33007882 PMCID: PMC7582772 DOI: 10.3390/ijms21197225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 09/28/2020] [Indexed: 01/22/2023] Open
Abstract
Obesity-induced adipocyte apoptosis promotes inflammation and insulin resistance. Src homology domain-containing inositol 5'-phosphatase 1 (SHIP1) is a key factor of apoptosis and inflammation. However, the role of SHIP1 in obesity-induced adipocyte apoptosis and autophagy is unclear. We found that diet-induced obesity (DIO) mice have significantly greater crown-like structures and terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL)-positive cells than ob/ob or control mice. Using RNA sequencing (RNA-seq) analysis, we identified that the apoptosis- and inflammation-related gene Ship1 is upregulated in DIO and ob/ob mice compared with control mice. In particular, DIO mice had more SHIP1-positive macrophages and lysosomal-associated membrane protein 1 (LAMP1) as well as a higher B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax)/Bcl-2 ratio compared with ob/ob or control mice. Furthermore, caloric restriction attenuated adipose tissue inflammation, apoptosis, and autophagy by reversing increases in SHIP1-associated macrophages, Bax/Bcl2-ratio, and autophagy in DIO and ob/ob mice. These results demonstrate that DIO, not ob/ob, aggravates adipocyte inflammation, apoptosis, and autophagy due to differential SHIP1 expression. The evidence of decreased SHIP1-mediated inflammation, apoptosis, and autophagy indicates new therapeutic approaches for obesity-induced chronic inflammatory diseases.
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5
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Abstract
Phagocytosis is a pivotal immunological process, and its discovery by Elia Metchnikoff in 1882 was a step toward the establishment of the innate immune system as a separate branch of immunology. Elia Metchnikoff received the Nobel Prize in physiology and medicine for this discovery in 1908. Since its discovery almost 140 years before, phagocytosis remains the hot topic of research in immunology. The phagocytosis research has seen a great advancement since its first discovery. Functionally, phagocytosis is a simple immunological process required to engulf and remove pathogens, dead cells and tumor cells to maintain the immune homeostasis. However, mechanistically, it is a very complex process involving different mechanisms, induced and regulated by several pattern recognition receptors, soluble pattern recognition molecules, scavenger receptors (SRs) and opsonins. These mechanisms involve the formation of phagosomes, their maturation into phagolysosomes causing pathogen destruction or antigen synthesis to present them to major histocompatibility complex molecules for activating an adaptive immune response. Any defect in this mechanism may predispose the host to certain infections and inflammatory diseases (autoinflammatory and autoimmune diseases) along with immunodeficiency. The article is designed to discuss its mechanistic complexity at each level, varying from phagocytosis induction to phagolysosome resolution.
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Affiliation(s)
- Vijay Kumar
- Faculty of Medicine, Children's Health Queensland Clinical Unit, School of Clinical Medicine, Mater Research, University of Queensland, ST Lucia, Brisbane, Queensland, Australia.,Faculty of Medicine, School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Queensland, Australia
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6
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Pedicone C, Fernandes S, Dungan OM, Dormann SM, Viernes DR, Adhikari AA, Choi LB, De Jong EP, Chisholm JD, Kerr WG. Pan-SHIP1/2 inhibitors promote microglia effector functions essential for CNS homeostasis. J Cell Sci 2020; 133:jcs238030. [PMID: 31780579 PMCID: PMC10682645 DOI: 10.1242/jcs.238030] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/21/2019] [Indexed: 12/11/2022] Open
Abstract
We show here that both SHIP1 (Inpp5d) and its paralog SHIP2 (Inppl1) are expressed at protein level in microglia. To examine whether targeting of SHIP paralogs might influence microglial physiology and function, we tested the capacity of SHIP1-selective, SHIP2-selective and pan-SHIP1/2 inhibitors for their ability to impact on microglia proliferation, lysosomal compartment size and phagocytic function. We find that highly potent pan-SHIP1/2 inhibitors can significantly increase lysosomal compartment size, and phagocytosis of dead neurons and amyloid beta (Aβ)1-42 by microglia in vitro We show that one of the more-potent and water-soluble pan-SHIP1/2 inhibitors, K161, can penetrate the blood-brain barrier. Consistent with this, K161 increases the capacity of CNS-resident microglia to phagocytose Aβ and apoptotic neurons following systemic administration. These findings provide the first demonstration that small molecule modulation of microglia function in vivo is feasible, and suggest that dual inhibition of the SHIP1 and 2 paralogs can provide a novel means to enhance basal microglial homeostatic functions for therapeutic purposes in Alzheimer's disease and, possibly, other types of dementia where increased microglial function could be beneficial.
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Affiliation(s)
- Chiara Pedicone
- Department of Microbiology & Immunology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Sandra Fernandes
- Department of Microbiology & Immunology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Otto M Dungan
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - Shawn M Dormann
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - Dennis R Viernes
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - Arijit A Adhikari
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - Lydia B Choi
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - Ebbing P De Jong
- Proteomics and Mass Spectrometry Core Facility, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - John D Chisholm
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
| | - William G Kerr
- Department of Microbiology & Immunology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Department of Chemistry, Syracuse University, Syracuse, NY 13210, USA
- Department of Pediatrics, SUNY Upstate Medical University, Syracuse, NY 13210, USA
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7
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The NADPH Oxidase and the Phagosome. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1246:153-177. [DOI: 10.1007/978-3-030-40406-2_9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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8
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Sheffield DA, Jepsen MR, Feeney SJ, Bertucci MC, Sriratana A, Naughtin MJ, Dyson JM, Coppel RL, Mitchell CA. The myotubularin MTMR4 regulates phagosomal phosphatidylinositol 3-phosphate turnover and phagocytosis. J Biol Chem 2019; 294:16684-16697. [PMID: 31543504 DOI: 10.1074/jbc.ra119.009133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 09/11/2019] [Indexed: 01/31/2023] Open
Abstract
Macrophage phagocytosis is required for effective clearance of invading bacteria and other microbes. Coordinated phosphoinositide signaling is critical both for phagocytic particle engulfment and subsequent phagosomal maturation to a degradative organelle. Phosphatidylinositol 3-phosphate (PtdIns(3)P) is a phosphoinositide that is rapidly synthesized and degraded on phagosomal membranes, where it recruits FYVE domain- and PX motif-containing proteins that promote phagosomal maturation. However, the molecular mechanisms that regulate PtdIns(3)P removal from the phagosome have remained unclear. We report here that a myotubularin PtdIns(3)P 3-phosphatase, myotubularin-related protein-4 (MTMR4), regulates macrophage phagocytosis. MTMR4 overexpression reduced and siRNA-mediated Mtmr4 silencing increased levels of cell-surface immunoglobulin receptors (i.e. Fcγ receptors (FcγRs)) on RAW 264.7 macrophages, associated with altered pseudopodal F-actin. Furthermore, MTMR4 negatively regulated the phagocytosis of IgG-opsonized particles, indicating that MTMR4 inhibits FcγR-mediated phagocytosis, and was dynamically recruited to phagosomes of macrophages during phagocytosis. MTMR4 overexpression decreased and Mtmr4-specific siRNA expression increased the duration of PtdIns(3)P on phagosomal membranes. Macrophages treated with Mtmr4-specific siRNA were more resistant to Mycobacterium marinum-induced phagosome arrest, associated with increased maturation of mycobacterial phagosomes, indicating that extended PtdIns(3)P signaling on phagosomes in the Mtmr4-knockdown cells permitted trafficking of phagosomes to acidic late endosomal and lysosomal compartments. In conclusion, our findings indicate that MTMR4 regulates PtdIns(3)P degradation in macrophages and thereby controls phagocytosis and phagosomal maturation.
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Affiliation(s)
- David A Sheffield
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia.,Department of Microbiology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Malene R Jepsen
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Sandra J Feeney
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Micka C Bertucci
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Absorn Sriratana
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Monica J Naughtin
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Jennifer M Dyson
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Ross L Coppel
- Department of Microbiology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Christina A Mitchell
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
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9
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Zhu Y, Crowley SC, Latimer AJ, Lewis GM, Nash R, Kucenas S. Migratory Neural Crest Cells Phagocytose Dead Cells in the Developing Nervous System. Cell 2019; 179:74-89.e10. [PMID: 31495570 DOI: 10.1016/j.cell.2019.08.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 07/16/2019] [Accepted: 08/01/2019] [Indexed: 12/20/2022]
Abstract
During neural tube closure and spinal cord development, many cells die in both the central and peripheral nervous systems (CNS and PNS, respectively). However, myeloid-derived professional phagocytes have not yet colonized the trunk region during early neurogenesis. How apoptotic cells are removed from this region during these stages remains largely unknown. Using live imaging in zebrafish, we demonstrate that neural crest cells (NCCs) respond rapidly to dying cells and phagocytose cellular debris around the neural tube. Additionally, NCCs have the ability to enter the CNS through motor exit point transition zones and clear debris in the spinal cord. Surprisingly, NCCs phagocytosis mechanistically resembles macrophage phagocytosis and their recruitment toward cellular debris is mediated by interleukin-1β. Taken together, our results reveal a role for NCCs in phagocytosis of debris in the developing nervous system before the presence of professional phagocytes.
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Affiliation(s)
- Yunlu Zhu
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Samantha C Crowley
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Andrew J Latimer
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Gwendolyn M Lewis
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Rebecca Nash
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Sarah Kucenas
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA.
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10
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Abstract
Phagosomal ROS generation is critical for our immune defense against microbial infections. Quantitative assessment of phagosomal ROS production is required to understand the complex relationship between the phagocyte and the microbe, in particular for pathogens that resist phagosomal destruction. ROS detection is difficult due to the transient nature of the reactive species and their multiple interactions with the environment. Direct labeling of phagocytic prey with a ROS-sensitive dye allows to target the dye into the phagosome and to follow the kinetics of phagosomal ROS production on a single phagosome base. Here we describe the basic labeling procedure, the quality assessment, and the imaging technique to achieve this kinetic analysis.
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Affiliation(s)
- Sophie Dupré-Crochet
- LCP, CNRS UMR 8000, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Marie Erard
- LCP, CNRS UMR 8000, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Oliver Nüβe
- LCP, CNRS UMR 8000, Université Paris-Sud, Université Paris-Saclay, Orsay, France.
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11
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Noster J, Persicke M, Chao TC, Krone L, Heppner B, Hensel M, Hansmeier N. Impact of ROS-Induced Damage of TCA Cycle Enzymes on Metabolism and Virulence of Salmonella enterica serovar Typhimurium. Front Microbiol 2019; 10:762. [PMID: 31105651 PMCID: PMC6491894 DOI: 10.3389/fmicb.2019.00762] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 03/26/2019] [Indexed: 01/10/2023] Open
Abstract
Salmonella enterica serovar Typhimurium (STM) is exposed to reactive oxygen species (ROS) originating from aerobic respiration, antibiotic treatment, and the oxidative burst occurring inside the Salmonella-containing vacuole (SCV) within host cells. ROS damage cellular compounds, thereby impairing bacterial viability and inducing cell death. Proteins containing iron–sulfur (Fe–S) clusters are particularly sensitive and become non-functional upon oxidation. Comprising five enzymes with Fe–S clusters, the TCA cycle is a pathway most sensitive toward ROS. To test the impact of ROS-mediated metabolic perturbations on bacterial physiology, we analyzed the proteomic and metabolic profile of STM deficient in both cytosolic superoxide dismutases (ΔsodAB). Incapable of detoxifying superoxide anions (SOA), endogenously generated SOA accumulate during growth. ΔsodAB showed reduced abundance of aconitases, leading to a metabolic profile similar to that of an aconitase-deficient strain (ΔacnAB). Furthermore, we determined a decreased expression of acnA in STM ΔsodAB. While intracellular proliferation in RAW264.7 macrophages and survival of methyl viologen treatment were not reduced for STM ΔacnAB, proteomic profiling revealed enhanced stress response. We conclude that ROS-mediated reduced expression and damage of aconitase does not impair bacterial viability or virulence, but might increase ROS amounts in STM, which reinforces the bactericidal effects of antibiotic treatment and immune responses of the host.
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Affiliation(s)
- Janina Noster
- Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Marcus Persicke
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Tzu-Chiao Chao
- Institute of Environmental Change and Society, University of Regina, Regina, SK, Canada
| | - Lena Krone
- Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Bianca Heppner
- Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Michael Hensel
- Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
| | - Nicole Hansmeier
- Abteilung Mikrobiologie, Universität Osnabrück, Osnabrück, Germany.,Institute of Environmental Change and Society, University of Regina, Regina, SK, Canada.,Luther College, University of Regina, Regina, SK, Canada
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12
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Piacenza L, Trujillo M, Radi R. Reactive species and pathogen antioxidant networks during phagocytosis. J Exp Med 2019; 216:501-516. [PMID: 30792185 PMCID: PMC6400530 DOI: 10.1084/jem.20181886] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/04/2019] [Accepted: 02/04/2019] [Indexed: 11/23/2022] Open
Abstract
The generation of phagosomal cytotoxic reactive species (i.e., free radicals and oxidants) by activated macrophages and neutrophils is a crucial process for the control of intracellular pathogens. The chemical nature of these species, the reactions they are involved in, and the subsequent effects are multifaceted and depend on several host- and pathogen-derived factors that influence their production rates and catabolism inside the phagosome. Pathogens rely on an intricate and synergistic antioxidant armamentarium that ensures their own survival by detoxifying reactive species. In this review, we discuss the generation, kinetics, and toxicity of reactive species generated in phagocytes, with a focus on the response of macrophages to internalized pathogens and concentrating on Mycobacterium tuberculosis and Trypanosoma cruzi as examples of bacterial and parasitic infection, respectively. The ability of pathogens to deal with host-derived reactive species largely depends on the competence of their antioxidant networks at the onset of invasion, which in turn can tilt the balance toward pathogen survival, proliferation, and virulence over redox-dependent control of infection.
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Affiliation(s)
- Lucía Piacenza
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Madia Trujillo
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Rafael Radi
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
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13
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Dobranowski P, Sly LM. SHIP negatively regulates type II immune responses in mast cells and macrophages. J Leukoc Biol 2018; 103:1053-1064. [PMID: 29345374 DOI: 10.1002/jlb.3mir0817-340r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 12/11/2017] [Accepted: 12/14/2017] [Indexed: 12/13/2022] Open
Abstract
SHIP is a hematopoietic-specific lipid phosphatase that dephosphorylates PI3K-generated PI(3,4,5)-trisphosphate. SHIP removes this second messenger from the cell membrane blunting PI3K activity in immune cells. Thus, SHIP negatively regulates mast cell activation downstream of multiple receptors. SHIP has been referred to as the "gatekeeper" of mast cell degranulation as loss of SHIP dramatically increases degranulation or permits degranulation in response to normally inert stimuli. SHIP also negatively regulates Mϕ activation, including both pro-inflammatory cytokine production downstream of pattern recognition receptors, and alternative Mϕ activation by the type II cytokines, IL-4, and IL-13. In the SHIP-deficient (SHIP-/- ) mouse, increased mast cell and Mϕ activation leads to spontaneous inflammatory pathology at mucosal sites, which is characterized by high levels of type II inflammatory cytokines. SHIP-/- mast cells and Mϕs have both been implicated in driving inflammation in the SHIP-/- mouse lung. SHIP-/- Mϕs drive Crohn's disease-like intestinal inflammation and fibrosis, which is dependent on heightened responses to innate immune stimuli generating IL-1, and IL-4 inducing abundant arginase I. Both lung and gut pathology translate to human disease as low SHIP levels and activity have been associated with allergy and with Crohn's disease in people. In this review, we summarize seminal literature and recent advances that provide insight into SHIP's role in mast cells and Mϕs, the contribution of these cell types to pathology in the SHIP-/- mouse, and describe how these findings translate to human disease and potential therapies.
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Affiliation(s)
- Peter Dobranowski
- Division of Gastroenterology, Department of Pediatrics, BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Laura M Sly
- Division of Gastroenterology, Department of Pediatrics, BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
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14
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Erard M, Dupré-Crochet S, Nüße O. Biosensors for spatiotemporal detection of reactive oxygen species in cells and tissues. Am J Physiol Regul Integr Comp Physiol 2018; 314:R667-R683. [PMID: 29341828 DOI: 10.1152/ajpregu.00140.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Redox biology has become a major issue in numerous areas of physiology. Reactive oxygen species (ROS) have a broad range of roles from signal transduction to growth control and cell death. To understand the nature of these roles, accurate measurement of the reactive compounds is required. An increasing number of tools for ROS detection is available; however, the specificity and sensitivity of these tools are often insufficient. Furthermore, their specificity has been rarely evaluated in complex physiological conditions. Many ROS probes are sensitive to environmental conditions in particular pH, which may interfere with ROS detection and cause misleading results. Accurate detection of ROS in physiology and pathophysiology faces additional challenges concerning the precise localization of the ROS and the timing of their production and disappearance. Certain ROS are membrane permeable, and certain ROS probes move across cells and organelles. Targetable ROS probes such as fluorescent protein-based biosensors are required for accurate localization. Here we analyze these challenges in more detail, provide indications on the strength and weakness of current tools for ROS detection, and point out developments that will provide improved ROS detection methods in the future. There is no universal method that fits all situations in physiology and cell biology. A detailed knowledge of the ROS probes is required to choose the appropriate method for a given biological problem. The knowledge of the shortcomings of these probes should also guide the development of new sensors.
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Affiliation(s)
- Marie Erard
- Université Paris-Sud, Université Paris-Saclay , Orsay , France.,Centre National de la Recherche Scientifique, Laboratoire de Chimie Physique , Orsay , France
| | - Sophie Dupré-Crochet
- Université Paris-Sud, Université Paris-Saclay , Orsay , France.,Centre National de la Recherche Scientifique, Laboratoire de Chimie Physique , Orsay , France
| | - Oliver Nüße
- Centre National de la Recherche Scientifique, Laboratoire de Chimie Physique , Orsay , France
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15
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Nault L, Bouchab L, Dupré-Crochet S, Nüße O, Erard M. Environmental Effects on Reactive Oxygen Species Detection-Learning from the Phagosome. Antioxid Redox Signal 2016; 25:564-76. [PMID: 27225344 DOI: 10.1089/ars.2016.6747] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
SIGNIFICANCE Reactive oxygen species (ROS) fulfill numerous roles in biology ranging from signal transduction to the induction of cell death. To advance our understanding of these sometimes contradictory roles, quantitative, specific, and sensitive ROS measurements are required. RECENT ADVANCES Several organic or genetically encoded probes were successfully developed for ROS detection. CRITICAL ISSUES In some cases, ROS production occurs in a harsh environment such as low pH or high concentration of proteases. However, the ROS sensor may be sensitive to such environmental conditions and therefore becomes inaccurate. While the sensitivity of many ROS sensors to pH is known, many other environmental conditions remain unexplored. This article illustrates the interference between ROS sensors and their environment using the phagosome as an example. In the phagosome, pH changes, high concentration of ROS, and the presence of many proteases generate a hostile and rapidly changing environment. FUTURE DIRECTIONS Difficulties due to cell movement and continuous formation of new phagosomes can be reduced by ratio measurements, if appropriate dyes are identified. For detection in live cells and subcellular locations, fluorescent proteins (FPs) offer several advantages and are used to create biosensors for ROS. Some FPs are directly sensitive to certain ROS as shown here. Although this may compromise their use in an environment with high levels of ROS, it can also be exploited for ROS measurement directly with the FPs themselves. For all types of ROS detection, we suggest a set of basic guidelines for testing the environmental sensitivity of an ROS sensor. Antioxid. Redox Signal. 25, 564-576.
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Affiliation(s)
- Laurent Nault
- Laboratoire de Chimie Physique, Université Paris-Sud, CNRS UMR 8000, Université Paris Saclay , Orsay, France
| | - Leïla Bouchab
- Laboratoire de Chimie Physique, Université Paris-Sud, CNRS UMR 8000, Université Paris Saclay , Orsay, France
| | - Sophie Dupré-Crochet
- Laboratoire de Chimie Physique, Université Paris-Sud, CNRS UMR 8000, Université Paris Saclay , Orsay, France
| | - Oliver Nüße
- Laboratoire de Chimie Physique, Université Paris-Sud, CNRS UMR 8000, Université Paris Saclay , Orsay, France
| | - Marie Erard
- Laboratoire de Chimie Physique, Université Paris-Sud, CNRS UMR 8000, Université Paris Saclay , Orsay, France
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16
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Deciphering the roles of phosphoinositide lipids in phagolysosome biogenesis. Commun Integr Biol 2016; 9:e1174798. [PMID: 27489580 PMCID: PMC4951175 DOI: 10.1080/19420889.2016.1174798] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 03/29/2016] [Accepted: 03/31/2016] [Indexed: 01/01/2023] Open
Abstract
Professional phagocytes engulf microbial invaders into plasma membrane-derived phagosomes. These mature into microbicidal phagolysosomes, leading to killing of the ingested microbe. Phagosome maturation involves sequential fusion of the phagosome with early endosomes, late endosomes, and the main degradative compartments in cells, lysosomes. Some bacterial pathogens manipulate the phosphoinositide (PIP) composition of phagosome membranes and are not delivered to phagolysosomes, pointing at a role of PIPs in phagosome maturation. This hypothesis is supported by comprehensive microscopic studies. Recently, cell-free reconstitution of fusion between phagosomes and endo(lyso)somes identified phosphatidylinositol 4-phosphate [PI(4)P] and phosphatidylinositol 3-phosphate [PI(3)P] as key regulators of phagolysosome biogenesis. Here, we describe the emerging roles of PIPs in phagosome maturation and we present tools to study PIP involvement in phagosome trafficking using intact cells or purified compartments.
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17
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Pyle DM, Yang VS, Gruchalla RS, Farrar JD, Gill MA. IgE cross-linking critically impairs human monocyte function by blocking phagocytosis. J Allergy Clin Immunol 2013; 131:491-500.e1-5. [PMID: 23374271 DOI: 10.1016/j.jaci.2012.11.037] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 11/21/2012] [Accepted: 11/27/2012] [Indexed: 12/26/2022]
Abstract
BACKGROUND IgE cross-linking triggers many cellular processes that drive allergic disease. While the role of IgE in mediating allergic responses is best described on basophils and mast cells, expression of the high-affinity IgE receptor on other innate immune cells, including monocytes, suggests that it may affect the function of these cells in allergic environments. OBJECTIVE To determine the effect of IgE cross-linking on the function of human monocytes. METHODS Monocytes purified from healthy donor blood samples were cultured for 4 to 96 hours with media alone, a cross-linking anti-IgE antibody or control IgG. Surface CD14 and CD64 expression and secreted cytokine concentrations were determined. Monocyte function was determined by assessing (1) phagocytosis of Escherichia coli or apoptotic HEp2 cells and (2) killing of intracellular E coli. Select experiments were performed on monocytes obtained from participants with elevated versus normal serum IgE concentrations. RESULTS IgE cross-linking on monocytes increased CD14 expression and induced secretion of TNF-α, IL-6, and autoregulatory IL-10. These effects were greatest in individuals with elevated serum IgE concentrations. In contrast, IgE cross-linking reduced CD64 expression and significantly impaired phagocytic function without disrupting the capacity of monocytes to kill bacteria. CONCLUSIONS IgE cross-linking drives monocyte proinflammatory processes and autoregulatory IL-10 in a serum IgE-dependent manner. In contrast, monocyte phagocytic function is critically impaired by IgE cross-linking. Our findings suggest that IgE cross-linking on monocytes may contribute to allergic disease by both enhancing detrimental inflammatory responses and concomitantly crippling phagocytosis, a primary mechanism used by these cells to resolve inflammation.
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Affiliation(s)
- David M Pyle
- Department of Immunology, UT Southwestern Medical Center, Dallas, Tex 75390, USA
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18
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Dupré-Crochet S, Erard M, Nüβe O. ROS production in phagocytes: why, when, and where? J Leukoc Biol 2013; 94:657-70. [PMID: 23610146 DOI: 10.1189/jlb.1012544] [Citation(s) in RCA: 339] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In the phagocytosis field, ROS production by the phagocyte NOX has been associated with pathogen killing for the last 50 years. Since the discovery of nonphagocyte NOX, numerous other roles for ROS production have been identified. Oxidative stress and ROS-mediated signaling have received much attention in recent years. Much lower concentrations of ROS may be required for signaling compared with microbial killing. Based on the discoveries in nonphagocytic cells, it became logical to look for ROS functions distinct from pathogen killing, even in phagocytes. ROS are now linked to various forms of cell death, to chemotaxis, and to numerous modifications of cellular processes, including the NOX itself. ROS functions are clearly concentration-dependent over a wide range of concentrations. How much is required for which function? Which species are required for how much time? Is ROS signaling only a side effect of bactericidal ROS production? One major obstacle to answer these questions is the difficulty of reliable quantitative ROS detection. Signal transduction often takes place on a subcellular scale over periods of seconds or minutes, so the detection methods need to provide appropriate time and space resolution. We present examples of local ROS production, decreased degradation, signaling events, and potentially ROS-sensitive functions. We attempt to illustrate the current limitations for quantitative spatiotemporal ROS detection and point out directions for ongoing development. Probes for localized ROS detection and for combined detection of ROS, together with protein localization or other cellular parameters, are constantly improved.
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19
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Bréchard S, Plançon S, Tschirhart EJ. New insights into the regulation of neutrophil NADPH oxidase activity in the phagosome: a focus on the role of lipid and Ca(2+) signaling. Antioxid Redox Signal 2013; 18:661-76. [PMID: 22867131 PMCID: PMC3549206 DOI: 10.1089/ars.2012.4773] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
SIGNIFICANCE Reactive oxygen species, produced by the phagosomal NADPH oxidase of neutrophils, play a significant physiological role during normal defense. Their role is not only to kill invading pathogens, but also to act as modulators of global physiological functions of phagosomes. Given the importance of NADPH oxidase in the immune system, its activity has to be decisively controlled by distinctive mechanisms to ensure appropriate regulation at the phagosome. RECENT ADVANCES Here, we describe the signal transduction pathways that regulate phagosomal NADPH oxidase in neutrophils, with an emphasis on the role of lipid metabolism and intracellular Ca(2+) mobilization. CRITICAL ISSUES The potential involvement of Ca(2+)-binding S100A8 and S100A9 proteins, known to interact with the plasma membrane NADPH oxidase, is also considered. FUTURE DIRECTIONS Recent technical progress in advanced live imaging microscopy will permit to focus more accurately on phagosomal rather than plasma membrane NADPH oxidase regulation during neutrophil phagocytosis.
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Affiliation(s)
- Sabrina Bréchard
- Calcium Signaling and Inflammation Group, Life Sciences Research Unit, University of Luxembourg, Luxembourg, Luxembourg
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20
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Foster JG, Blunt MD, Carter E, Ward SG. Inhibition of PI3K signaling spurs new therapeutic opportunities in inflammatory/autoimmune diseases and hematological malignancies. Pharmacol Rev 2012; 64:1027-54. [PMID: 23023033 DOI: 10.1124/pr.110.004051] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The phosphoinositide 3-kinase/mammalian target of rapamycin/protein kinase B (PI3K/mTOR/Akt) signaling pathway is central to a plethora of cellular mechanisms in a wide variety of cells including leukocytes. Perturbation of this signaling cascade is implicated in inflammatory and autoimmune disorders as well as hematological malignancies. Proteins within the PI3K/mTOR/Akt pathway therefore represent attractive targets for therapeutic intervention. There has been a remarkable evolution of PI3K inhibitors in the past 20 years from the early chemical tool compounds to drugs that are showing promise as anticancer agents in clinical trials. The use of animal models and pharmacological tools has expanded our knowledge about the contribution of individual class I PI3K isoforms to immune cell function. In addition, class II and III PI3K isoforms are emerging as nonredundant regulators of immune cell signaling revealing potentially novel targets for disease treatment. Further complexity is added to the PI3K/mTOR/Akt pathway by a number of novel signaling inputs and feedback mechanisms. These can present either caveats or opportunities for novel drug targets. Here, we consider recent advances in 1) our understanding of the contribution of individual PI3K isoforms to immune cell function and their relevance to inflammatory/autoimmune diseases as well as lymphoma and 2) development of small molecules with which to inhibit the PI3K pathway. We also consider whether manipulating other proximal elements of the PI3K signaling cascade (such as class II and III PI3Ks or lipid phosphatases) are likely to be successful in fighting off different immune diseases.
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Affiliation(s)
- John G Foster
- Inflammatory Cell Biology Laboratory, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath, UK.
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21
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Blunt MD, Ward SG. Pharmacological targeting of phosphoinositide lipid kinases and phosphatases in the immune system: success, disappointment, and new opportunities. Front Immunol 2012; 3:226. [PMID: 22876243 PMCID: PMC3410520 DOI: 10.3389/fimmu.2012.00226] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 07/12/2012] [Indexed: 12/24/2022] Open
Abstract
The predominant expression of the γ and δ isoforms of PI3K in cells of hematopoietic lineage prompted speculation that inhibitors of these isoforms could offer opportunities for selective targeting of PI3K in the immune system in a range of immune-related pathologies. While there has been some success in developing PI3Kδ inhibitors, progress in developing selective inhibitors of PI3Kγ has been rather disappointing. This has prompted the search for alternative targets with which to modulate PI3K signaling specifically in the immune system. One such target is the SH2 domain-containing inositol-5-phosphatase-1 (SHIP-1) which de-phosphorylates PI(3,4,5)P3 at the D5 position of the inositol ring to create PI(3,4)P2. In this article, we first describe the current state of PI3K isoform-selective inhibitor development. We then focus on the structure of SHIP-1 and its function in the immune system. Finally, we consider the current state of development of small molecule compounds that potently and selectively modulate SHIP activity and which offer novel opportunities to manipulate PI3K mediated signaling in the immune system.
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Affiliation(s)
- Matthew D Blunt
- Inflammatory Cell Biology Laboratory, Department of Pharmacy and Pharmacology, University of Bath Bath, UK
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22
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Blunt MD, Ward SG. Targeting PI3K isoforms and SHIP in the immune system: new therapeutics for inflammation and leukemia. Curr Opin Pharmacol 2012; 12:444-51. [PMID: 22483603 DOI: 10.1016/j.coph.2012.02.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 02/23/2012] [Indexed: 10/28/2022]
Abstract
PI3K is critical for the normal function of the immune system, however dysregulated PI3K mediated signaling has been linked to the development of many immune mediated pathologies. This review describes current progress in the development of isoform-specific PI3K inhibitors that hold promise for the treatment of hematopoietic malignancies as well as for inflammatory and autoimmune diseases. A SH2-domain containing inositol-5-phosphatase (SHIP) is a regulator of PI3K signaling, and is also discussed as a potential drug target for immunomodulation and the treatment of leukemia. Recent progress has been made in the development of small molecule compounds that potently and selectively modulate SHIP activity and hence provide a novel mechanism to alter PI3K mediated signaling.
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Affiliation(s)
- Matthew D Blunt
- Inflammatory Cell Biology Laboratory, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath, BA2 7AY, UK
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23
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Nüsse O. Biochemistry of the phagosome: the challenge to study a transient organelle. ScientificWorldJournal 2011; 11:2364-81. [PMID: 22194668 PMCID: PMC3236389 DOI: 10.1100/2011/741046] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 10/26/2011] [Indexed: 12/21/2022] Open
Abstract
Phagocytes are specialized cells of the immune system, designed to engulf and destroy harmful microorganisms inside the newly formed phagosome. The latter is an intracellular organelle that is transformed into a toxic environment within minutes and disappears once the pathogen is destroyed. Reactive oxygen species and reactive nitrogen species are produced inside the phagosome. Intracellular granules or lysosomes of the phagocyte fuse with the phagosome and liberate their destructive enzymes. This process of phagocytosis efficiently protects against most infections; however, some microorganisms avoid their destruction and cause severe damage. To understand such failure of phagosomal killing, we need to learn more about the actual destruction process in the phagosome. This paper summarizes methods to investigate the biochemistry of the phagosome and discusses some of their limitations. In accordance with the nature of the phagosome, the issue of localization and temporal dynamics is emphasized, and recent developments are highlighted.
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Affiliation(s)
- Oliver Nüsse
- Département de Biologie, Université Paris-Sud, Bâtiment 443, rue des Adeles, 91405 Orsay, France.
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24
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Tlili A, Erard M, Faure MC, Baudin X, Piolot T, Dupré-Crochet S, Nüße O. Stable accumulation of p67phoxat the phagosomal membrane and ROS production within the phagosome. J Leukoc Biol 2011; 91:83-95. [DOI: 10.1189/jlb.1210701] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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25
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Kaye Y, Golani Y, Singer Y, Leshem Y, Cohen G, Ercetin M, Gillaspy G, Levine A. Inositol polyphosphate 5-phosphatase7 regulates the production of reactive oxygen species and salt tolerance in Arabidopsis. PLANT PHYSIOLOGY 2011; 157:229-41. [PMID: 21677096 PMCID: PMC3165872 DOI: 10.1104/pp.111.176883] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Plants possess remarkable ability to adapt to adverse environmental conditions. The adaptation process involves the removal of many molecules from organelles, especially membranes, and replacing them with new ones. The process is mediated by an intracellular vesicle-trafficking system regulated by phosphatidylinositol (PtdIns) kinases and phosphatases. Although PtdIns comprise a fraction of membrane lipids, they function as major regulators of stress signaling. We analyzed the role of PtdIns 5-phosphatases (5PTases) in plant salt tolerance. The Arabidopsis (Arabidopsis thaliana) genome contains 15 At5PTases. We analyzed salt sensitivity in nine At5ptase mutants and identified one (At5ptase7) that showed increased sensitivity, which was improved by overexpression. At5ptase7 mutants demonstrated reduced production of reactive oxygen species (ROS). Supplementation of mutants with exogenous PtdIns dephosphorylated at the D5' position restored ROS production, while PtdIns(4,5)P(2), PtdIns(3,5)P(2), or PtdIns(3,4,5)P(3) were ineffective. Compromised salt tolerance was also observed in mutant NADPH Oxidase, in agreement with the low ROS production and salt sensitivity of PtdIns 3-kinase mutants and with the inhibition of NADPH oxidase activity in wild-type plants. Localization of green fluorescent protein-labeled At5PTase7 occurred in the plasma membrane and nucleus, places that coincided with ROS production. Analysis of salt-responsive gene expression showed that mutants failed to induce the RD29A and RD22 genes, which contain several ROS-dependent elements in their promoters. Inhibition of ROS production by diphenylene iodonium suppressed gene induction. In summary, our results show a nonredundant function of At5PTase7 in salt stress response by regulating ROS production and gene expression.
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Gag induces the coalescence of clustered lipid rafts and tetraspanin-enriched microdomains at HIV-1 assembly sites on the plasma membrane. J Virol 2011; 85:9749-66. [PMID: 21813604 DOI: 10.1128/jvi.00743-11] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The HIV-1 structural protein Gag associates with two types of plasma membrane microdomains, lipid rafts and tetraspanin-enriched microdomains (TEMs), both of which have been proposed to be platforms for HIV-1 assembly. However, a variety of studies have demonstrated that lipid rafts and TEMs are distinct microdomains in the absence of HIV-1 infection. To measure the impact of Gag on microdomain behaviors, we took advantage of two assays: an antibody-mediated copatching assay and a Förster resonance energy transfer (FRET) assay that measures the clustering of microdomain markers in live cells without antibody-mediated patching. We found that lipid rafts and TEMs copatched and clustered to a greater extent in the presence of membrane-bound Gag in both assays, suggesting that Gag induces the coalescence of lipid rafts and TEMs. Substitutions in membrane binding motifs of Gag revealed that, while Gag membrane binding is necessary to induce coalescence of lipid rafts and TEMs, either acylation of Gag or binding of phosphatidylinositol-(4,5)-bisphosphate is sufficient. Finally, a Gag derivative that is defective in inducing membrane curvature appeared less able to induce lipid raft and TEM coalescence. A higher-resolution analysis of assembly sites by correlative fluorescence and scanning electron microscopy showed that coalescence of clustered lipid rafts and TEMs occurs predominantly at completed cell surface virus-like particles, whereas a transmembrane raft marker protein appeared to associate with punctate Gag fluorescence even in the absence of cell surface particles. Together, these results suggest that different membrane microdomain components are recruited in a stepwise manner during assembly.
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27
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Park H, Ishihara D, Cox D. Regulation of tyrosine phosphorylation in macrophage phagocytosis and chemotaxis. Arch Biochem Biophys 2011; 510:101-11. [PMID: 21356194 PMCID: PMC3114168 DOI: 10.1016/j.abb.2011.02.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 02/15/2011] [Accepted: 02/18/2011] [Indexed: 12/22/2022]
Abstract
Macrophages display a large variety of surface receptors that are critical for their normal cellular functions in host defense, including finding sites of infection (chemotaxis) and removing foreign particles (phagocytosis). However, inappropriate regulation of these processes can lead to human diseases. Many of these receptors utilize tyrosine phosphorylation cascades to initiate and terminate signals leading to cell migration and clearance of infection. Actin remodeling dominates these processes and many regulators have been identified. This review focuses on how tyrosine kinases and phosphatases regulate actin dynamics leading to macrophage chemotaxis and phagocytosis.
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Affiliation(s)
- Haein Park
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Dan Ishihara
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Dianne Cox
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
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28
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Tlili A, Dupré-Crochet S, Erard M, Nüsse O. Kinetic analysis of phagosomal production of reactive oxygen species. Free Radic Biol Med 2011; 50:438-47. [PMID: 21111807 DOI: 10.1016/j.freeradbiomed.2010.11.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 11/09/2010] [Accepted: 11/17/2010] [Indexed: 01/23/2023]
Abstract
Phagocytes produce large quantities of reactive oxygen species for pathogen killing; however, the kinetics and amplitude of ROS production on the level of individual phagosomes are poorly understood. This is mainly due to the lack of appropriate methods for quantitative ROS detection with microscopic resolution. We covalently attached the ROS-sensitive dye dichlorodihydrofluorescein (DCFH(2)) to yeast particles and investigated their fluorescence due to oxidation in vitro and in live phagocytes. In vitro, the dye was oxidized by H(2)O(2) plus horseradish peroxidase but also by HOCl. The latter produced a previously unrecognized oxidation product with red-shifted excitation and emission spectra and a characteristic difference in the shape of the excitation spectrum near 480 nm. Millimolar HOCl bleached the DCFH(2) oxidation products. Inside phagosomes, DCFH(2)-labeled yeast were oxidized for several minutes in a strictly NADPH oxidase-dependent manner as shown by video microscopy. Inhibition of the NADPH oxidase rapidly stopped the fluorescence increase of the particles. At least two characteristic kinetics of oxidation were distinguished and the variability of DCFH(2) oxidation in phagosomes was much larger than the variability upon oxidation in vitro. We conclude that DCFH(2)-yeast is a valuable tool to investigate the kinetics and amplitude of ROS production in individual phagosomes.
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29
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Abstract
SHIP1 is at the nexus of intracellular signaling pathways in immune cells that mediate bone marrow (BM) graft rejection, production of inflammatory and immunosuppressive cytokines, immunoregulatory cell formation, the BM niche that supports development of the immune system, and immune cancers. This review summarizes how SHIP participates in normal immune physiology or the pathologies that result when SHIP is mutated. This review also proposes that SHIP can have either inhibitory or activating roles in cell signaling that are determined by whether signaling pathways distal to PI3K are promoted by SHIP's substrate (PI(3,4,5)P(3) ) or its product (PI(3,4)P(2) ). This review also proposes the "two PIP hypothesis" that postulates that both SHIP's product and its substrate are necessary for a cancer cell to achieve and sustain a malignant state. Finally, due to the recent discovery of small molecule antagonists and agonists for SHIP, this review discusses potential therapeutic settings where chemical modulation of SHIP might be of benefit.
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Affiliation(s)
- William G Kerr
- SUNY Upstate Medical University, Syracuse, New York, USA.
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30
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Ballinger MN, Welliver T, Straight S, Peters-Golden M, Swanson JA. Transient increase in cyclic AMP localized to macrophage phagosomes. PLoS One 2010; 5:e13962. [PMID: 21085604 PMCID: PMC2978719 DOI: 10.1371/journal.pone.0013962] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 10/17/2010] [Indexed: 11/18/2022] Open
Abstract
Cyclic AMP (cAMP) regulates many biological processes and cellular functions. The importance of spatially localized intracellular gradients of cAMP is increasingly appreciated. Previous work in macrophages has shown that cAMP is produced during phagocytosis and that elevated cAMP levels suppress host defense functions, including generation of proinflammatory mediators, phagocytosis and killing. However, the spatial and kinetic characteristics of cAMP generation in phagocytosing macrophages have yet to be examined. Using a Förster resonance energy transfer (FRET)-based cAMP biosensor, we measured the generation of cAMP in live macrophages. We detected no difference in bulk intracellular cAMP levels between resting cells and cells actively phagocytosing IgG-opsonized particles. However, analysis with the biosensor revealed a rapid decrease in FRET signal corresponding to a transient burst of cAMP production localized to the forming phagosome. cAMP levels returned to baseline after the particle was internalized. These studies indicate that localized increases in cAMP accompany phagosome formation and provide a framework for a more complete understanding of how cAMP regulates macrophage host defense functions.
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Affiliation(s)
- Megan N. Ballinger
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Michigan Health Systems, Ann Arbor, Michigan, United States of America
| | - Timothy Welliver
- Department of Microbiology and Immunology, University of Michigan Health Systems, Ann Arbor, Michigan, United States of America
- Program in Immunology, University of Michigan Health Systems, Ann Arbor, Michigan, United States of America
| | - Samuel Straight
- Department of Microbiology and Immunology, University of Michigan Health Systems, Ann Arbor, Michigan, United States of America
| | - Marc Peters-Golden
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Michigan Health Systems, Ann Arbor, Michigan, United States of America
- Program in Immunology, University of Michigan Health Systems, Ann Arbor, Michigan, United States of America
| | - Joel A. Swanson
- Department of Microbiology and Immunology, University of Michigan Health Systems, Ann Arbor, Michigan, United States of America
- Program in Immunology, University of Michigan Health Systems, Ann Arbor, Michigan, United States of America
- * E-mail:
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Li XJ, Marchal CC, Stull ND, Stahelin RV, Dinauer MC. p47phox Phox homology domain regulates plasma membrane but not phagosome neutrophil NADPH oxidase activation. J Biol Chem 2010; 285:35169-79. [PMID: 20817944 DOI: 10.1074/jbc.m110.164475] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The assembly of cytosolic subunits p47(phox), p67(phox), and p40(phox) with flavocytochrome b(558) at the membrane is required for activating the neutrophil NADPH oxidase that generates superoxide for microbial killing. The p47(phox) subunit plays a critical role in oxidase assembly. Recent studies showed that the p47(phox) Phox homology (PX) domain mediates phosphoinositide binding in vitro and regulates phorbol ester-induced NADPH oxidase activity in a K562 myeloid cell model. Because the importance of the p47(phox) PX domain in neutrophils is unclear, we investigated its role using p47(phox) knock-out (KO) mouse neutrophils to express human p47(phox) and derivatives harboring R90A mutations in the PX domain that result in loss of phosphoinositide binding. Human p47(phox) proteins were expressed at levels similar to endogenous murine p47(phox), with the exception of a chronic granulomatous disease-associated R42Q mutant that was poorly expressed, and wild type human p47(phox) rescued p47(phox) KO mouse neutrophil NADPH oxidase activity. Plasma membrane NAPDH oxidase activity was reduced in neutrophils expressing p47(phox) with Arg(90) substitutions, with substantial effects on responses to either phorbol ester or formyl-Met-Leu-Phe and more modest effects to particulate stimuli. In contrast, p47(phox) Arg(90) mutants supported normal levels of intracellular NADPH oxidase activity during phagocytosis of a variety of particles and were recruited to phagosome membranes. This study defines a differential and agonist-dependent role of the p47(phox) PX domain for neutrophil NADPH oxidase activation.
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Affiliation(s)
- Xing Jun Li
- From the Department of Pediatrics (Hematology/Oncology), Herman B Wells Center for Pediatric Research, Riley Hospital for Children, and
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Tiwari S, Choi HP, Matsuzawa T, Pypaert M, MacMicking JD. Targeting of the GTPase Irgm1 to the phagosomal membrane via PtdIns(3,4)P(2) and PtdIns(3,4,5)P(3) promotes immunity to mycobacteria. Nat Immunol 2009; 10:907-17. [PMID: 19620982 PMCID: PMC2715447 DOI: 10.1038/ni.1759] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 05/22/2009] [Indexed: 12/16/2022]
Abstract
Vertebrate immunity to infection enlists a newly identified family of 47-kilodalton immunity-related GTPases (IRGs). One IRG in particular, Irgm1, is essential for macrophage host defense against phagosomal pathogens, including Mycobacterium tuberculosis (Mtb). Here we show that Irgm1 targets the mycobacterial phagosome through lipid-mediated interactions with phosphatidylinositol-3,4-bisphosphate (PtdIns(3,4)P(2)) and PtdIns(3,4,5)P(3). An isolated Irgm1 amphipathic helix conferred lipid binding in vitro and in vivo. Substitutions in this region blocked phagosome recruitment and failed to complement the antimicrobial defect in Irgm1(-/-) macrophages. Removal of PtdIns(3,4,5)P(3) or inhibition of class I phosphatidylinositol-3-OH kinase (PI(3)K) mimicked this effect in wild-type cells. Cooperation between Irgm1 and PI(3)K further facilitated the engagement of Irgm1 with its fusogenic effectors at the site of infection, thereby ensuring pathogen-directed responses during innate immunity.
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Affiliation(s)
- Sangeeta Tiwari
- Section of Microbial Pathogenesis, Boyer Center for Molecular Medicine Yale University School of Medicine, New Haven, CT 06510. U.S.A
| | - Han-Pil Choi
- Section of Microbial Pathogenesis, Boyer Center for Molecular Medicine Yale University School of Medicine, New Haven, CT 06510. U.S.A
| | - Takeshi Matsuzawa
- Section of Microbial Pathogenesis, Boyer Center for Molecular Medicine Yale University School of Medicine, New Haven, CT 06510. U.S.A
| | - Marc Pypaert
- Department of Cell Biology, Center for Cell and Molecular Imaging Yale University School of Medicine, New Haven, CT 06510. U.S.A
| | - John D. MacMicking
- Section of Microbial Pathogenesis, Boyer Center for Molecular Medicine Yale University School of Medicine, New Haven, CT 06510. U.S.A
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VanderVen BC, Yates RM, Russell DG. Intraphagosomal Measurement of the Magnitude and Duration of the Oxidative Burst. Traffic 2009. [DOI: 10.1111/j.1600-0854.2008.00877.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Generation of an oxidative burst within the phagosomes of neutrophils, dendritic cells and macrophages is an essential component of the innate immune system. To examine the kinetics of the oxidative burst in the macrophage phagosome, we developed two new assays using beads coated with oxidation-sensitive fluorochromes.These assays permitted quantification and temporal resolution of the oxidative burst within the phagosome. The macrophage phagosomal oxidative burst is short lived,with oxidation of bead-associated substrates reaching maximal activity within 30 min following phagocytosis.Additionally, the extent and rate of macrophage phagosomal substrate oxidation were subject to immunomodulation by activation with lipopolysaccharide and/or interferon-gamma.
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Affiliation(s)
- Brian C VanderVen
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
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The role of the inositol polyphosphate 5-phosphatases in cellular function and human disease. Biochem J 2009; 419:29-49. [PMID: 19272022 DOI: 10.1042/bj20081673] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Phosphoinositides are membrane-bound signalling molecules that regulate cell proliferation and survival, cytoskeletal reorganization and vesicular trafficking by recruiting effector proteins to cellular membranes. Growth factor or insulin stimulation induces a canonical cascade resulting in the transient phosphorylation of PtdIns(4,5)P(2) by PI3K (phosphoinositide 3-kinase) to form PtdIns(3,4,5)P(3), which is rapidly dephosphorylated either by PTEN (phosphatase and tensin homologue deleted on chromosome 10) back to PtdIns(4,5)P(2), or by the 5-ptases (inositol polyphosphate 5-phosphatases), generating PtdIns(3,4)P(2). The 5-ptases also hydrolyse PtdIns(4,5)P(2), forming PtdIns4P. Ten mammalian 5-ptases have been identified, which share a catalytic mechanism similar to that of the apurinic/apyrimidinic endonucleases. Gene-targeted deletion of 5-ptases in mice has revealed that these enzymes regulate haemopoietic cell proliferation, synaptic vesicle recycling, insulin signalling, endocytosis, vesicular trafficking and actin polymerization. Several studies have revealed that the molecular basis of Lowe's syndrome is due to mutations in the 5-ptase OCRL (oculocerebrorenal syndrome of Lowe). Futhermore, the 5-ptases SHIP [SH2 (Src homology 2)-domain-containing inositol phosphatase] 2, SKIP (skeletal muscle- and kidney-enriched inositol phosphatase) and 72-5ptase (72 kDa 5-ptase)/Type IV/Inpp5e (inositol polyphosphate 5-phosphatase E) are implicated in negatively regulating insulin signalling and glucose homoeostasis in specific tissues. SHIP2 polymorphisms are associated with a predisposition to insulin resistance. Gene profiling studies have identified changes in the expression of various 5-ptases in specific cancers. In addition, 5-ptases such as SHIP1, SHIP2 and 72-5ptase/Type IV/Inpp5e regulate macrophage phagocytosis, and SHIP1 also controls haemopoietic cell proliferation. Therefore the 5-ptases are a significant family of signal-modulating enzymes that govern a plethora of cellular functions by regulating the levels of specific phosphoinositides. Emerging studies have implicated their loss or gain of function in human disease.
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Kannan S, Huang H, Seeger D, Audet A, Chen Y, Huang C, Gao H, Li S, Wu M. Alveolar epithelial type II cells activate alveolar macrophages and mitigate P. Aeruginosa infection. PLoS One 2009; 4:e4891. [PMID: 19305493 PMCID: PMC2654511 DOI: 10.1371/journal.pone.0004891] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Accepted: 02/02/2009] [Indexed: 12/20/2022] Open
Abstract
Although alveolar epithelial type II cells (AECII) perform substantial roles in the maintenance of alveolar integrity, the extent of their contributions to immune defense is poorly understood. Here, we demonstrate that AECII activates alveolar macrophages (AM) functions, such as phagocytosis using a conditioned medium from AECII infected by P. aeruginosa. AECII-derived chemokine MCP-1, a monocyte chemoattractant protein, was identified as a main factor in enhancing AM function. We proposed that the enhanced immune potency of AECII may play a critical role in alleviation of bacterial propagation and pneumonia. The ability of phagocytosis and superoxide release by AM was reduced by MCP-1 neutralizing antibodies. Furthermore, MCP-1(-/-) mice showed an increased bacterial burden under PAO1 and PAK infection vs. wt littermates. AM from MCP-1(-/-) mice also demonstrated less superoxide and impaired phagocytosis over the controls. In addition, AECII conditioned medium increased the host defense of airway in MCP-1(-/-) mice through the activation of AM function. Mechanistically, we found that Lyn mediated NFkappaB activation led to increased gene expression and secretion of MCP-1. Consequently Lyn(-/-) mice had reduced MCP-1 secretion and resulted in a decrease in superoxide and phagocytosis by AM. Collectively, our data indicate that AECII may serve as an immune booster for fighting bacterial infections, particularly in severe immunocompromised conditions.
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Affiliation(s)
- Shibichakravarthy Kannan
- Department of Biochemistry and Molecular Biology, University of North Dakota, Grand Forks, North Dakota, United States of America
| | - Huang Huang
- Department of Biochemistry and Molecular Biology, University of North Dakota, Grand Forks, North Dakota, United States of America
| | - Drew Seeger
- Department of Biochemistry and Molecular Biology, University of North Dakota, Grand Forks, North Dakota, United States of America
| | - Aaron Audet
- Department of Biochemistry and Molecular Biology, University of North Dakota, Grand Forks, North Dakota, United States of America
| | - Yaoyu Chen
- Division of Hematology/Oncology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Canhua Huang
- State Key Laboratory for Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Hongwei Gao
- Department of Biochemistry and Molecular Biology, University of North Dakota, Grand Forks, North Dakota, United States of America
| | - Shaoguang Li
- Division of Hematology/Oncology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Min Wu
- Department of Biochemistry and Molecular Biology, University of North Dakota, Grand Forks, North Dakota, United States of America
- State Key Laboratory for Biotherapy, West China Hospital, Sichuan University, Chengdu, China
- * E-mail:
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Abstract
The use of fluorescent probes is one of the most powerful techniques for gaining spatial and temporal knowledge of dynamic events within living cells. Localized increases in the signal from cytosolic fluorescent protein constructs, for example, are frequently used as evidence for translocation of proteins to specific sites within the cell. However, differences in optical and geometrical properties of cytoplasm can influence the recorded intensity of the probe signal. Pseudopodia are especially problematic because their cytoplasmic properties can cause abrupt increases in fluorescent signal of both GFP and fluorescein. Investigators should therefore be cautious when interpreting fluorescence changes within a cell, as these can result from either translocation of the probe or changes in the optical properties of the milieu surrounding the probe.
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Affiliation(s)
- Sharon Dewitt
- Neutrophil Signalling Group and Department of Haematology, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, Wales, UK
| | - Richard L. Darley
- Neutrophil Signalling Group and Department of Haematology, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, Wales, UK
| | - Maurice B. Hallett
- Neutrophil Signalling Group and Department of Haematology, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, Wales, UK
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