1
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Izquierdo P, Jolivet RB, Attwell D, Madry C. Amyloid plaques and normal ageing have differential effects on microglial Ca 2+ activity in the mouse brain. Pflugers Arch 2024; 476:257-270. [PMID: 37966547 PMCID: PMC10791787 DOI: 10.1007/s00424-023-02871-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 10/02/2023] [Accepted: 10/24/2023] [Indexed: 11/16/2023]
Abstract
In microglia, changes in intracellular calcium concentration ([Ca2+]i) may regulate process motility, inflammasome activation, and phagocytosis. However, while neurons and astrocytes exhibit frequent spontaneous Ca2+ activity, microglial Ca2+ signals are much rarer and poorly understood. Here, we studied [Ca2+]i changes of microglia in acute brain slices using Fluo-4-loaded cells and mice expressing GCaMP5g in microglia. Spontaneous Ca2+ transients occurred ~ 5 times more frequently in individual microglial processes than in their somata. We assessed whether microglial Ca2+ responses change in Alzheimer's disease (AD) using AppNL-G-F knock-in mice. Proximity to Aβ plaques strongly affected microglial Ca2+ activity. Although spontaneous Ca2+ transients were unaffected in microglial processes, they were fivefold more frequent in microglial somata near Aβ plaques than in wild-type microglia. Microglia away from Aβ plaques in AD mice showed intermediate properties for morphology and Ca2+ responses, partly resembling those of wild-type microglia. By contrast, somatic Ca2+ responses evoked by tissue damage were less intense in microglia near Aβ plaques than in wild-type microglia, suggesting different mechanisms underlying spontaneous vs. damage-evoked Ca2+ signals. Finally, as similar processes occur in neurodegeneration and old age, we studied whether ageing affected microglial [Ca2+]i. Somatic damage-evoked Ca2+ responses were greatly reduced in microglia from old mice, as in the AD mice. In contrast to AD, however, old age did not alter the occurrence of spontaneous Ca2+ signals in microglial somata but reduced the rate of events in processes. Thus, we demonstrate distinct compartmentalised Ca2+ activity in microglia from healthy, aged and AD-like brains.
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Affiliation(s)
- Pablo Izquierdo
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
| | - Renaud B Jolivet
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
- Maastricht Centre for Systems Biology (MaCSBio), Maastricht University, Paul-Henri Spaaklaan 1, 6229 EN, Maastricht, The Netherlands
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK.
| | - Christian Madry
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK.
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Institute of Neurophysiology, 10117, Berlin, Germany.
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2
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Acharya TK, Sahu RP, Kumar S, Kumar S, Rokade TP, Chakraborty R, Dubey NK, Shikha D, Chawla S, Goswami C. Function and regulation of thermosensitive ion channel TRPV4 in the immune system. CURRENT TOPICS IN MEMBRANES 2022; 89:155-188. [DOI: 10.1016/bs.ctm.2022.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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3
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Johansson C, Kirsebom FCM. Neutrophils in respiratory viral infections. Mucosal Immunol 2021; 14:815-827. [PMID: 33758367 PMCID: PMC7985581 DOI: 10.1038/s41385-021-00397-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 11/16/2020] [Accepted: 11/18/2020] [Indexed: 02/04/2023]
Abstract
Viral respiratory infections are a common cause of severe disease, especially in infants, people who are immunocompromised, and in the elderly. Neutrophils, an important innate immune cell, infiltrate the lungs rapidly after an inflammatory insult. The most well-characterized effector mechanisms by which neutrophils contribute to host defense are largely extracellular and the involvement of neutrophils in protection from numerous bacterial and fungal infections is well established. However, the role of neutrophils in responses to viruses, which replicate intracellularly, has been less studied. It remains unclear whether and, by which underlying immunological mechanisms, neutrophils contribute to viral control or confer protection against an intracellular pathogen. Furthermore, neutrophils need to be tightly regulated to avoid bystander damage to host tissues. This is especially relevant in the lung where damage to delicate alveolar structures can compromise gas exchange with life-threatening consequences. It is inherently less clear how neutrophils can contribute to host immunity to viruses without causing immunopathology and/or exacerbating disease severity. In this review, we summarize and discuss the current understanding of how neutrophils in the lung direct immune responses to viruses, control viral replication and spread, and cause pathology during respiratory viral infections.
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Affiliation(s)
- Cecilia Johansson
- National Heart and Lung Institute, Imperial College London, London, UK.
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4
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Tarique AA, Evron T, Zhang G, Tepper MA, Morshed MM, Andersen ISG, Begum N, Sly PD, Fantino E. Anti-inflammatory effects of lenabasum, a cannabinoid receptor type 2 agonist, on macrophages from cystic fibrosis. J Cyst Fibros 2020; 19:823-829. [PMID: 32387042 DOI: 10.1016/j.jcf.2020.03.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/12/2020] [Accepted: 03/24/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND Lenabasum is an oral synthetic cannabinoid receptor type 2 agonist previously shown to reduce the production of key airway pro-inflammatory cytokines known to play a role in cystic fibrosis (CF). In a double-blinded, randomized, placebo-control phase 2 study, lenabasum lowered the rate of pulmonary exacerbation among patients with CF. The present study was undertaken to investigate anti-inflammatory mechanisms of lenabasum exhibits in CF macrophages. METHODS We used monocyte-derived macrophages (MDMs) from healthy donors (n = 15), MDMs with CFTR inhibited with C-172 (n = 5) and MDMs from patients with CF (n = 4). Monocytes were differentiated to macrophages and polarized into classically activated (M1) macrophages by LPS or alternatively activated (M2) macrophages by IL-13 in presence or absence of lenabasum. RESULTS Lenabasum had no effect on differentiation, polarization and function of macrophages from healthy individuals. However, in CF macrophages lenabasum downregulated macrophage polarization into the pro-inflammatory M1 phenotype and secretion of the pro-inflammatory cytokines IL-8 and TNF-α in a dose-dependent manner. An improvement in phagocytic activity was also observed following lenabasum treatment. Although lenabasum did not restore the impaired polarization of anti-inflammatory M2 macrophage, it reduced the levels of IL-13 and enhanced the endocytic function of CF MDMs. The effects of lenabasum on MDMs with CFTR inhibited by C-172 were not as obvious. CONCLUSION In CF macrophages lenabasum modulates macrophage polarization and function in vitro in a way that would reduce inflammation in vivo. Further studies are warranted to determine the link between activating the CBR2 receptor and CFTR.
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Affiliation(s)
- Abdullah A Tarique
- Child Health Research Centre (CHRC), The University of Queensland, Brisbane, Australia
| | - Tama Evron
- Corbus Pharmaceuticals, Inc., Norwood, MA, USA
| | | | | | - Mohammed M Morshed
- Child Health Research Centre (CHRC), The University of Queensland, Brisbane, Australia
| | - Isabella S G Andersen
- Child Health Research Centre (CHRC), The University of Queensland, Brisbane, Australia
| | - Nelufa Begum
- Child Health Research Centre (CHRC), The University of Queensland, Brisbane, Australia
| | - Peter D Sly
- Child Health Research Centre (CHRC), The University of Queensland, Brisbane, Australia.
| | - Emmanuelle Fantino
- Child Health Research Centre (CHRC), The University of Queensland, Brisbane, Australia
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5
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Gupta N, Goswami R, Alharbi MO, Biswas D, Rahaman SO. TRPV4 is a regulator in P. gingivalis lipopolysaccharide-induced exacerbation of macrophage foam cell formation. Physiol Rep 2020; 7:e14069. [PMID: 30980509 PMCID: PMC6461712 DOI: 10.14814/phy2.14069] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 03/21/2019] [Accepted: 03/25/2019] [Indexed: 01/21/2023] Open
Abstract
Porphyromonas gingivalis (P.g), a major causative agent of periodontitis, has been linked to atherosclerosis, a chronic inflammatory vascular disease. Recent studies have suggested a link between periodontitis and arterial stiffness, a risk factor for atherosclerosis. However, the mechanisms by which P.g infection contributes to atherogenesis remain elusive. The formation of lipid-laden macrophage "foam cells" is critically important to development and progression of atherosclerosis. We have obtained evidence that TRPV4 (transient receptor potential channel of the vanilloid subfamily 4), a mechanosensitive channel, is a regulator of macrophage foam cell formation both in response to P.g-derived lipopolysaccharide (PgLPS) or to an increase in matrix stiffness. Importantly, we found that TRPV4 activity (Ca2+ influx) was increased in response to PgLPS. Genetic deletion or chemical antagonism of TRPV4 channels blocked PgLPS-triggered exacerbation of oxidized LDL (oxLDL)-mediated foam cell formation. Mechanistically, we found that (1) TRPV4 regulated oxLDL uptake but not its cell surface binding in macrophages; (2) reduced foam cell formation in TRPV4 null cells was independent of expression of CD36, a predominant receptor for oxLDL, and (3) co-localization of TRPV4 and CD36 on the macrophage plasma membrane was sensitive to the increased level of matrix stiffness occurring in the presence of PgLPS. Altogether, our results suggest that TRPV4 channels play an essential role in P.g-induced exacerbation of macrophage foam cell generation through a mechanism that modulates uptake of oxLDL.
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Affiliation(s)
- Nabyendu Gupta
- Department of Nutrition and Food Science, University of Maryland, College Park, Maryland
| | - Rishov Goswami
- Department of Nutrition and Food Science, University of Maryland, College Park, Maryland
| | - Mazen O Alharbi
- Department of Nutrition and Food Science, University of Maryland, College Park, Maryland
| | - Debabrata Biswas
- Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland
| | - Shaik O Rahaman
- Department of Nutrition and Food Science, University of Maryland, College Park, Maryland
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Mukherjee K, Khatua B, Mandal C. Sialic Acid-Siglec-E Interactions During Pseudomonas aeruginosa Infection of Macrophages Interferes With Phagosome Maturation by Altering Intracellular Calcium Concentrations. Front Immunol 2020; 11:332. [PMID: 32184783 PMCID: PMC7059019 DOI: 10.3389/fimmu.2020.00332] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 02/10/2020] [Indexed: 11/24/2022] Open
Abstract
Pseudomonas aeruginosa (PA) is commonly associated with nosocomial and chronic infections of lungs. We have earlier demonstrated that an acidic sugar, sialic acid, is present in PA which is recognized and bound by sialic acid binding immunoglobulin type lectins (siglecs) expressed on neutrophils. Here, we have tried to gain a detailed insight into the immunosuppressive role of sialic acid-siglec interactions in macrophage-mediated clearance of sialylated PA (PA+Sia). We have demonstrated that PA+Sia shows enhanced binding (~1.5-fold) to macrophages due to additional interactions between sialic acids and siglec-E and exhibited more phagocytosis. However, internalization of PA+Sia is associated with a reduction in respiratory burst and increase in anti-inflammatory cytokines secretion which is reversed upon desialylation of the bacteria. Phagocytosis of PA+Sia is also associated with reduced intracellular calcium ion concentrations and altered calcium-dependent signaling which negatively affects phagosome maturation. Consequently, although more PA+Sia was localized in early phagosomes (Rab5 compartment), only fewer bacteria reach into the late phagosomal compartment (Rab7). Possibly, this leads to reduced phagosome lysosome fusion where reduced numbers of PA+Sia are trafficked into lysosomes, compared to PA−Sia. Thus, internalized PA+Sia remain viable and replicates intracellularly in macrophages. We have also demonstrated that such siglec-E-sialic acid interaction recruited SHP-1/SHP-2 phosphatases which modulate MAPK and NF-κB signaling pathways. Disrupting sialic acid-siglec-E interaction by silencing siglec-E in macrophages results in improved bactericidal response against PA+Sia characterized by robust respiratory burst, enhanced intracellular calcium levels and nuclear translocation of p65 component of NF-κB complex leading to increased pro-inflammatory cytokine secretion. Taken together, we have identified that sialic acid-siglec-E interactions is another pathway utilized by PA in order to suppress macrophage antimicrobial responses and inhibit phagosome maturation, thereby persisting as an intracellular pathogen in macrophages.
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Affiliation(s)
- Kaustuv Mukherjee
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Biswajit Khatua
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Chitra Mandal
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
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The GPR120 Agonist TUG-891 Inhibits the Motility and Phagocytosis of Mouse Alveolar Macrophages. BIOMED RESEARCH INTERNATIONAL 2020; 2020:1706168. [PMID: 32149083 PMCID: PMC7056993 DOI: 10.1155/2020/1706168] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 12/30/2019] [Accepted: 02/05/2020] [Indexed: 01/08/2023]
Abstract
Movement and phagocytosis characterize the fundamental actions of macrophages. Although it is known that the free fatty acid receptor GPR120 is expressed in macrophages and regulates cytokine expression to exert anti-inflammatory activities, the effects of GPR120 activation on the motility and phagocytosis of macrophages are not clear. In this study, mouse alveolar macrophages (AM) were stimulated with the GPR120 agonist TUG-891, and the changes in cell motility, intracellular Ca2+ concentration ([Ca2+]i), and the ability of phagocytosis were measured. Mouse AM in controls exhibited active movement in vitro, and TUG-891 significantly restrained AM movement. Meanwhile, TUG-891 stimulated a quick increase in [Ca2+]i in AM, which was blocked separately by the Gq protein inhibitor YM-254890, the phospholipase C (PLC) inhibitor U73122, or depletion of endoplasmic reticulum (ER) Ca2+ store by thapsigargin. The inhibition of AM movement by TUG-891 was eliminated by YM-254890, U73122, thapsigargin, and chelation of cytosolic Ca2+ by BAPTA. Moreover, TUG-891 inhibited AM phagocytosis of fluorescent microspheres, which was also blocked by YM-254890, U73122, thapsigargin, and BAPTA. In conclusion, GPR120 activation in mouse AM increases [Ca2+]i but inhibits the motility and phagocytosis via Gq protein/PLC-mediated Ca2+ release from ER Ca2+ store.
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8
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Role of macrophage TRPV4 in inflammation. J Transl Med 2020; 100:178-185. [PMID: 31645630 PMCID: PMC7261496 DOI: 10.1038/s41374-019-0334-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 08/19/2019] [Accepted: 08/30/2019] [Indexed: 01/05/2023] Open
Abstract
Transient receptor ion channels have emerged as immensely important channels/receptors in diverse physiological and pathological responses. Of particular interest is the transient receptor potential channel subfamily V member 4 (TRPV4), which is a polymodal, nonselective, calcium-permeant cation channel, and is activated by both endogenous and exogenous stimuli. Both neuronal and nonneuronal cells express functional TRPV4, which is responsive to a variety of biochemical and biomechanical stimuli. Emerging discoveries have advanced our understanding of the role of macrophage TRPV4 in numerous inflammatory diseases. In lung injury, TRPV4 mediates macrophage phagocytosis, secretion of pro-resolution cytokines, and generation of reactive oxygen species. TRPV4 regulates lipid-laden macrophage foam cell formation, the hallmark of atheroinflammatory conditions, in response to matrix stiffness and lipopolysaccharide stimulation. Accumulating data also point to a role of macrophage TRPV4 in the pathogenesis of the foreign body response, a chronic inflammatory condition, through the formation of foreign body giant cells. Deletion of TRPV4 in macrophages suppresses the allergic and nonallergic itch in a mouse model, suggesting a role of TRPV4 in skin disease. Here, we discuss the current understanding of the role of macrophage TRPV4 in various inflammatory conditions.
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9
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A lysosomal K + channel regulates large particle phagocytosis by facilitating lysosome Ca 2+ release. Sci Rep 2020; 10:1038. [PMID: 31974459 PMCID: PMC6978423 DOI: 10.1038/s41598-020-57874-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 12/31/2019] [Indexed: 12/13/2022] Open
Abstract
Macrophages are highly specialized in removing large particles including dead cells and cellular debris. When stimulated, delivery of the intracellular lysosomal membranes is required for the formation of plasmalemmal pseudopods and phagosomes. As a key lysosomal Ca2+ channel, Transient Receptor Potential Mucolipin-1 (TRPML1) regulates lysosomal exocytosis and subsequent phagosome biogenesis, thereby promoting phagocytosis of large extracellular particles. Recently, we have suggested that TRPML1-mediated lysosomal exocytosis is essentially dependent on lysosomal big conductance Ca2+-activated potassium (BK) channel. Therefore, we predict that lysosomal BK channels regulate large particle phagocytosis. In this study, by using RAW264.7 macrophage cell line and bone marrow-derived macrophages, we show that although BK is dispensable for small particle uptake, loss of BK significantly inhibits the ingestion of large particles whereas activating BK increases the uptake of large particles. BK facilitating effect on large particle ingestion is inhibited by either blocking TRPML1 or suppressing lysosomal exocytosis. Additionally, the increased uptake of large particles by activating TRPML1 is eliminated by inhibiting BK. These data suggest that BK and TRPML1 are functionally coupled to regulate large particle phagocytosis through modulating lysosomal exocytosis.
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10
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Abstract
Calcification is a regulated physiological process occurring in bones and teeth. However, calcification is commonly found in soft tissues in association with aging and in a variety of diseases. Over the last two decades, it has emerged that calcification occurring in diseased arteries is not simply an inevitable build-up of insoluble precipitates of calcium phosphate. In some cases, it is an active process in which transcription factors drive conversion of vascular cells to an osteoblast or chondrocyte-like phenotype, with the subsequent production of mineralizing "matrix vesicles." Early studies of bone and cartilage calcification suggested roles for cellular calcium signaling in several of the processes involved in the regulation of bone calcification. Similarly, calcium signaling has recently been highlighted as an important component in the mechanisms regulating pathological calcification. The emerging hypothesis is that ectopic/pathological calcification occurs in tissues in which there is an imbalance in the regulatory mechanisms that actively prevent calcification. This review highlights the various ways that calcium signaling regulates tissue calcification, with a particular focus on pathological vascular calcification.
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Affiliation(s)
- Diane Proudfoot
- Signalling Division, Babraham Institute, Babraham, Cambridge CB22 3AT, United Kingdom
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11
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Angireddy R, Kazmi HR, Srinivasan S, Sun L, Iqbal J, Fuchs SY, Guha M, Kijima T, Yuen T, Zaidi M, Avadhani NG. Cytochrome c oxidase dysfunction enhances phagocytic function and osteoclast formation in macrophages. FASEB J 2019; 33:9167-9181. [PMID: 31063702 PMCID: PMC6662975 DOI: 10.1096/fj.201900010rr] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/15/2019] [Indexed: 12/20/2022]
Abstract
The mitochondria-to-nucleus retrograde signaling (MtRS) pathway aids in cellular adaptation to stress. We earlier reported that the Ca2+- and calcineurin-dependent MtRS induces macrophage differentiation to bone-resorbing osteoclasts. However, mechanisms through which macrophages sense and respond to cellular stress remain unclear. Here, we induced mitochondrial stress in macrophages by knockdown (KD) of subunits IVi1 or Vb of cytochrome c oxidase (CcO). Whereas both IVi1 and Vb KD impair CcO activity, IVi1 KD cells produced higher levels of cellular and mitochondrial reactive oxygen species with increased glycolysis. Additionally, IVi1 KD induced the activation of MtRS factors NF-κB, NFAT2, and C/EBPδ as well as inflammatory cytokines, NOS 2, increased phagocytic activity, and a greater osteoclast differentiation potential at suboptimal RANK-L concentrations. The osteoclastogenesis in IVi1 KD cells was reversed fully with an IL-6 inhibitor LMT-28, whereas there was minimal rescue of the enhanced phagocytosis in these cells. In agreement with our findings in cultured macrophages, primary bone marrow-derived macrophages from MPV17-/- mice, a model for mitochondrial dysfunction, also showed higher propensity for osteoclast formation. This is the first report showing that CcO dysfunction affects inflammatory pathways, phagocytic function, and osteoclastogenesis.-Angireddy, R., Kazmi, H. R., Srinivasan, S., Sun, L., Iqbal, J., Fuchs, S. Y., Guha, M., Kijima, T., Yuen, T., Zaidi, M., Avadhani, N. G. Cytochrome c oxidase dysfunction enhances phagocytic function and osteoclast formation in macrophages.
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Affiliation(s)
- Rajesh Angireddy
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hasan Raza Kazmi
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Satish Srinivasan
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Li Sun
- The Mount Sinai Bone Program, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jameel Iqbal
- The Mount Sinai Bone Program, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Serge Y. Fuchs
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Manti Guha
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Takashi Kijima
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Tony Yuen
- The Mount Sinai Bone Program, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Mone Zaidi
- The Mount Sinai Bone Program, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Narayan G. Avadhani
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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12
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Babuta M, Kumar S, Gourinath S, Bhattacharya S, Bhattacharya A. Calcium-binding protein EhCaBP3 is recruited to the phagocytic complex of Entamoeba histolytica by interacting with Arp2/3 complex subunit 2. Cell Microbiol 2018; 20:e12942. [PMID: 30133964 DOI: 10.1111/cmi.12942] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/07/2018] [Accepted: 08/01/2018] [Indexed: 12/26/2022]
Abstract
Phagocytosis is involved in invasive disease of the parasite Entamoeba histolytica. Upon binding of red blood cells, there is a sequential recruitment of EhC2PK, EhCaBP1, EhAK1, and Arp2/3 complex during the initiation phase. In addition, EhCaBP3 is also recruited to the site and, along with myosin 1B, is thought to be involved in progression of phagocytic cups from initiation to phagosome formation. However, it is not clear how EhCaBP3 gets recruited to the rest of the phagocytic machinery. Here, we show that EhARPC2, a subunit of Arp2/3 complex, interacts with EhCaBP3 in a Ca2+ -dependent manner both in vivo and in vitro. Imaging and pull down experiments suggest that interaction with EhARPC2 is required for the closure of cups and formation of phagosomes. Moreover, downregulation of EhARPC2 prevents localisation of EhCaBP3 to phagocytic cups, suggesting that EhCaBP3 is part of EhC2PK-EhCaBP1-EhAK1-Arp2/3 complex (EhARPC1) pathway. In conclusion, these results suggest that the EhCaBP3-EhARPC2 interaction helps to recruit EhCaBP3 along with myosin 1B to the phagocytic machinery that plays an indispensable role in E. histolytica phagocytosis.
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Affiliation(s)
- Mrigya Babuta
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sanjeev Kumar
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | - Sudha Bhattacharya
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Alok Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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13
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Mackay HL, Moore D, Hall C, Birkbak NJ, Jamal-Hanjani M, Karim SA, Phatak VM, Piñon L, Morton JP, Swanton C, Le Quesne J, Muller PAJ. Genomic instability in mutant p53 cancer cells upon entotic engulfment. Nat Commun 2018; 9:3070. [PMID: 30076358 PMCID: PMC6076230 DOI: 10.1038/s41467-018-05368-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 06/29/2018] [Indexed: 01/15/2023] Open
Abstract
Cell-in-cell (CIC) structures are commonly seen in tumours. Their biological significance remains unclear, although they have been associated with more aggressive tumours. Here we report that mutant p53 promotes CIC via live cell engulfment. Engulfed cells physically interfere in cell divisions of host cells and for cells without p53 this leads to host cell death. In contrast, mutant p53 host cells survive, display aberrant divisions, multinucleation and tripolar mitoses. In xenograft studies, CIC-rich p53 mutant/null co-cultures show enhanced tumour growth. Furthermore, our results show that CIC is common within lung adenocarcinomas, is an independent predictor of poor outcome and disease recurrence, is associated with mutant p53 expression and correlated to measures of heterogeneity and genomic instability. These findings suggest that pro-tumorigenic entotic engulfment activity is associated with mutant p53 expression, and the two combined are a key factor in genomic instability.
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Affiliation(s)
- Hannah L Mackay
- MRC Toxicology Unit, Lancaster Road, Leicester, LE1 9HN, UK
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - David Moore
- MRC Toxicology Unit, Lancaster Road, Leicester, LE1 9HN, UK
- Cancer studies, University of Leicester, Leicester, LE1 7RH, UK
| | - Callum Hall
- Cancer Research UK Manchester Institute, The University of Manchester | Alderley Park, Manchester, SK10 4TG, UK
| | - Nicolai J Birkbak
- Translational Cancer Therapeutics Laboratory, The Francis Crick Institute, 1 Midland Rd, London, NW1 1AT, UK
- Cancer Research UK Lung Cancer Centre of Excellence, University College London Cancer Institute, Paul O'Gorman Building 72 Huntley Street, London, WC1E 6BT, UK
| | - Mariam Jamal-Hanjani
- Department of Medical Oncology, University College London Hospitals, 235 Euston Rd, Fitzrovia, London, NW1 2BU, UK
- CRUK The Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Saadia A Karim
- Institute of Cancer Sciences, University of Glasgow, Switchback Road, Glasgow, G61 1BD, UK
| | | | - Lucia Piñon
- MRC Toxicology Unit, Lancaster Road, Leicester, LE1 9HN, UK
| | - Jennifer P Morton
- Institute of Cancer Sciences, University of Glasgow, Switchback Road, Glasgow, G61 1BD, UK
- Department of Histopathology, Glenfield Hospital, University Hospitals Leicester NHS Trust, Groby Road, Leicester, LE3 9QP, UK
| | - Charles Swanton
- Translational Cancer Therapeutics Laboratory, The Francis Crick Institute, 1 Midland Rd, London, NW1 1AT, UK
- Cancer Research UK Lung Cancer Centre of Excellence, University College London Cancer Institute, Paul O'Gorman Building 72 Huntley Street, London, WC1E 6BT, UK
- Department of Medical Oncology, University College London Hospitals, 235 Euston Rd, Fitzrovia, London, NW1 2BU, UK
| | - John Le Quesne
- MRC Toxicology Unit, Lancaster Road, Leicester, LE1 9HN, UK.
- Cancer studies, University of Leicester, Leicester, LE1 7RH, UK.
- Department of Histopathology, Glenfield Hospital, University Hospitals Leicester NHS Trust, Groby Road, Leicester, LE3 9QP, UK.
| | - Patricia A J Muller
- MRC Toxicology Unit, Lancaster Road, Leicester, LE1 9HN, UK.
- Cancer Research UK Manchester Institute, The University of Manchester | Alderley Park, Manchester, SK10 4TG, UK.
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14
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Yang L, Gu W, Cheung KH, Yan L, Tong BCK, Jiang Y, Yang J. InsP 3R-SEC5 interaction on phagosomes modulates innate immunity to Candida albicans by promoting cytosolic Ca 2+ elevation and TBK1 activity. BMC Biol 2018; 16:46. [PMID: 29703257 PMCID: PMC5921305 DOI: 10.1186/s12915-018-0507-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/20/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Candida albicans (C. albicans) invasion triggers antifungal innate immunity, and the elevation of cytoplasmic Ca2+ levels via the inositol 1,4,5-trisphosphate receptor (InsP3R) plays a critical role in this process. However, the molecular pathways linking the InsP3R-mediated increase in Ca2+ and immune responses remain elusive. RESULTS In the present study, we find that during C. albicans phagocytosis in macrophages, exocyst complex component 2 (SEC5) promotes InsP3R channel activity by binding to its C-terminal α-helix (H1), increasing cytosolic Ca2+ concentrations ([Ca2+]c). Immunofluorescence reveals enriched InsP3R-SEC5 complex formation on phagosomes, while disruption of the InsP3R-SEC5 interaction by recombinant H1 peptides attenuates the InsP3R-mediated Ca2+ elevation, leading to impaired phagocytosis. Furthermore, we show that C. albicans infection promotes the recruitment of Tank-binding kinase 1 (TBK1) by the InsP3R-SEC5 interacting complex, leading to the activation of TBK1. Subsequently, activated TBK1 phosphorylates interferon regulatory factor 3 (IRF-3) and mediates type I interferon responses, suggesting that the InsP3R-SEC5 interaction may regulate antifungal innate immune responses not only by elevating cytoplasmic Ca2+ but also by activating the TBK1-IRF-3 pathway. CONCLUSIONS Our data have revealed an important role of the InsP3R-SEC5 interaction in innate immune responses against C. albicans.
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Affiliation(s)
- Long Yang
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai, 200433, China.,Jinan Military General Hospital, 25 Shifan Road, Jinan, 250031, China
| | - Wenwen Gu
- NHFPC Key Laboratory of Reproduction Regulation, Shanghai Institute of Planned Parenthood Research, 2140 Xie Tu Road, Shanghai, 200032, China
| | - King-Ho Cheung
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Lan Yan
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai, 200433, China
| | | | - Yuanying Jiang
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai, 200433, China. .,School of Medicine, Tongji University, Shanghai, 200433, China.
| | - Jun Yang
- NHFPC Key Laboratory of Reproduction Regulation, Shanghai Institute of Planned Parenthood Research, 2140 Xie Tu Road, Shanghai, 200032, China.
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15
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Goswami R, Merth M, Sharma S, Alharbi MO, Aranda-Espinoza H, Zhu X, Rahaman SO. TRPV4 calcium-permeable channel is a novel regulator of oxidized LDL-induced macrophage foam cell formation. Free Radic Biol Med 2017; 110:142-150. [PMID: 28602913 DOI: 10.1016/j.freeradbiomed.2017.06.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 05/27/2017] [Accepted: 06/06/2017] [Indexed: 01/03/2023]
Abstract
Cardiovascular disease is the number one cause of death in United States, and atherosclerosis, a chronic inflammatory arterial disease, is the most dominant underlying pathology. Macrophages are thought to orchestrate atherosclerosis by generating lipid-laden foam cells and by secreting inflammatory mediators. Emerging data support a role for a mechanical factor, e.g., matrix stiffness, in regulation of macrophage function, vascular elasticity, and atherogenesis. However, the identity of the plasma membrane mechanosensor and the mechanisms by which pro-atherogenic signals are transduced/maintained are unknown. We have obtained evidence that TRPV4, an ion channel in the transient receptor potential vanilloid family and a known mechanosensor, is the likely mediator of oxidized low-density lipoprotein (oxLDL)-dependent macrophage foam cell formation, a critical process in atherogenesis. Specifically, we found that: i) genetic ablation of TRPV4 or pharmacologic inhibition of TRPV4 activity by a specific antagonist blocked oxLDL-induced macrophage foam cell formation, and ii) TRPV4 deficiency prevented pathophysiological range matrix stiffness or scratch-induced exacerbation of oxLDL-induced foam cell formation. Mechanistically, we found that: i) plasma membrane localization of TRPV4 was sensitized to the increasing level of matrix stiffness, ii) lack of foam cell formation in TRPV4 null cells was not due to lack of expression of CD36, a major receptor for oxLDL, and iii) TRPV4 channel activity regulated oxLDL uptake but not its binding on macrophages. Altogether, these findings identify a novel role for TRPV4 in regulating macrophage foam cell formation by modulating uptake of oxLDL. These findings suggest that therapeutic targeting of TRPV4 may provide a selective approach to the treatment of atherosclerosis.
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Affiliation(s)
- Rishov Goswami
- University of Maryland, Department of Nutrition and Food Science, College Park, MD 20742, USA
| | - Michael Merth
- University of Maryland, Department of Nutrition and Food Science, College Park, MD 20742, USA
| | - Shweta Sharma
- University of Maryland, Department of Nutrition and Food Science, College Park, MD 20742, USA
| | - Mazen O Alharbi
- University of Maryland, Department of Nutrition and Food Science, College Park, MD 20742, USA
| | - Helim Aranda-Espinoza
- University of Maryland, The Fischell Department of Bioengineering, College Park, MD 20742, USA
| | - Xiaoping Zhu
- University of Maryland, Department of Veterinary Medicine, College Park, MD 20742, USA
| | - Shaik O Rahaman
- University of Maryland, Department of Nutrition and Food Science, College Park, MD 20742, USA.
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16
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Hoare JI, Rajnicek AM, McCaig CD, Barker RN, Wilson HM. Electric fields are novel determinants of human macrophage functions. J Leukoc Biol 2015; 99:1141-51. [PMID: 26718542 DOI: 10.1189/jlb.3a0815-390r] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 12/18/2015] [Indexed: 01/08/2023] Open
Abstract
Macrophages are key cells in inflammation and repair, and their activity requires close regulation. The characterization of cues coordinating macrophage function has focused on biologic and soluble mediators, with little known about their responses to physical stimuli, such as the electrical fields that are generated naturally in injured tissue and which accelerate wound healing. To address this gap in understanding, we tested how properties of human monocyte-derived macrophages are regulated by applied electrical fields, similar in strengths to those established naturally. With the use of live-cell video microscopy, we show that macrophage migration is directed anodally by electrical fields as low as 5 mV/mm and is electrical field strength dependent, with effects peaking ∼300 mV/mm. Monocytes, as macrophage precursors, migrate in the opposite, cathodal direction. Strikingly, we show for the first time that electrical fields significantly enhance macrophage phagocytic uptake of a variety of targets, including carboxylate beads, apoptotic neutrophils, and the nominal opportunist pathogen Candida albicans, which engage different classes of surface receptors. These electrical field-induced functional changes are accompanied by clustering of phagocytic receptors, enhanced PI3K and ERK activation, mobilization of intracellular calcium, and actin polarization. Electrical fields also modulate cytokine production selectively and can augment some effects of conventional polarizing stimuli on cytokine secretion. Taken together, electrical signals have been identified as major contributors to the coordination and regulation of important human macrophage functions, including those essential for microbial clearance and healing. Our results open up a new area of research into effects of naturally occurring and clinically applied electrical fields in conditions where macrophage activity is critical.
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Affiliation(s)
- Joseph I Hoare
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Ann M Rajnicek
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Colin D McCaig
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Robert N Barker
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Heather M Wilson
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
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17
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Scheraga RG, Abraham S, Niese KA, Southern BD, Grove LM, Hite RD, McDonald C, Hamilton TA, Olman MA. TRPV4 Mechanosensitive Ion Channel Regulates Lipopolysaccharide-Stimulated Macrophage Phagocytosis. THE JOURNAL OF IMMUNOLOGY 2015; 196:428-36. [PMID: 26597012 DOI: 10.4049/jimmunol.1501688] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 11/01/2015] [Indexed: 12/31/2022]
Abstract
Macrophage phagocytosis of particles and pathogens is an essential aspect of innate host defense. Phagocytic function requires cytoskeletal rearrangements that depend on the interaction between macrophage surface receptors, particulates/pathogens, and the extracellular matrix. In the present study we determine the role of a mechanosensitive ion channel, transient receptor potential vanilloid 4 (TRPV4), in integrating the LPS and matrix stiffness signals to control macrophage phenotypic change for host defense and resolution from lung injury. We demonstrate that active TRPV4 mediates LPS-stimulated murine macrophage phagocytosis of nonopsonized particles (Escherichia coli) in vitro and opsonized particles (IgG-coated latex beads) in vitro and in vivo in intact mice. Intriguingly, matrix stiffness in the range seen in inflamed or fibrotic lung is required to sensitize the TRPV4 channel to mediate the LPS-induced increment in macrophage phagocytosis. Furthermore, TRPV4 is required for the LPS induction of anti-inflammatory/proresolution cytokines. These findings suggest that signaling through TRPV4, triggered by changes in extracellular matrix stiffness, cooperates with LPS-induced signals to mediate macrophage phagocytic function and lung injury resolution. These mechanisms are likely to be important in regulating macrophage function in the context of pulmonary infection and fibrosis.
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Affiliation(s)
- Rachel G Scheraga
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; Respiratory Institute, Cleveland Clinic, Cleveland, OH 44195; and
| | - Susamma Abraham
- Respiratory Institute, Cleveland Clinic, Cleveland, OH 44195; and
| | - Kathryn A Niese
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Brian D Southern
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; Respiratory Institute, Cleveland Clinic, Cleveland, OH 44195; and
| | - Lisa M Grove
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - R Duncan Hite
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; Respiratory Institute, Cleveland Clinic, Cleveland, OH 44195; and
| | - Christine McDonald
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | | | - Mitchell A Olman
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; Respiratory Institute, Cleveland Clinic, Cleveland, OH 44195; and
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18
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Receptor role of the annexin A2 in the mesothelial endocytosis of crocidolite fibers. J Transl Med 2015; 95:749-64. [PMID: 25915724 DOI: 10.1038/labinvest.2015.28] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 11/27/2014] [Accepted: 12/22/2014] [Indexed: 11/08/2022] Open
Abstract
Asbestos-induced mesothelioma is a worldwide problem. Parietal mesothelial cells internalize asbestos fibers that traverse the entire lung parenchyma, an action that is linked to mesothelial carcinogenesis. Thus far, vitronectin purified from serum reportedly enhances the internalization of crocidolite by mesothelial cells via integrin αvβ5. To reveal another mechanism by which mesothelial cells endocytose (phagocytose) asbestos, we first evaluated the effects of serum on asbestos uptake, which proved to be nonessential. Thereafter, we undertook a study to identify proteins on the surface of mesothelial cells (MeT5A) that act as receptors for asbestos uptake based on the assumption that receptors bind to asbestos with physical affinity. To this end, we incubated the membrane fraction of MeT5A cells with crocidolite or chrysotile and evaluated the adsorbed proteins using sodium dodecyl sulfate polyacrylamide gel analysis. Next, we extensively identified the proteins using an in-solution or in-gel digestion coupled with mass spectrometry. Among the identified proteins, annexin A2 (ANXA2) and transferrin receptor protein 1 (TFRC) were distinguished because of their high score and presence at the cell surface. Crocidolite uptake by MeT5A cells was significantly decreased by shRNA (short hairpin RNA)-induced knockdown of ANXA2 and direct blockade of cell surface ANXA2 using anti-ANXA2 antibody. In addition, abundant ANXA2 protein was present on the cell membrane of mesothelial cells, particularly facing the somatic cavity. These findings demonstrate that ANXA2 has a role in the mesothelial phagocytosis of crocidolite and may serve as its receptor.
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19
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Fettucciari K, Ponsini P, Palumbo C, Rosati E, Mannucci R, Bianchini R, Modesti A, Marconi P. Macrophage induced gelsolin in response to Group BStreptococcus(GBS) infection. Cell Microbiol 2014; 17:79-104. [DOI: 10.1111/cmi.12338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 07/04/2014] [Accepted: 07/31/2014] [Indexed: 12/20/2022]
Affiliation(s)
- Katia Fettucciari
- Department of Experimental Medicine; Perugia University; Perugia Italy
| | - Pamela Ponsini
- Department of Experimental Medicine; Perugia University; Perugia Italy
| | - Camilla Palumbo
- Department of Clinical Sciences and Translational Medicine; Tor Vergata University; Rome Italy
| | - Emanuela Rosati
- Department of Experimental Medicine; Perugia University; Perugia Italy
| | - Roberta Mannucci
- Department of Medicine, Laboratory of Image Analysis; Perugia University; Perugia Italy
| | - Rodolfo Bianchini
- Research Program for Receptor Biochemistry and Tumor Metabolism; Laura Bassi Centre of Expertise Therapep; Salzburg University Clinic; Salzburg Austria
- Department of Pediatrics; Paracelsus Medical University; Muellner Hauptstrasse Salzburg Austria
| | - Andrea Modesti
- Department of Clinical Sciences and Translational Medicine; Tor Vergata University; Rome Italy
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20
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Lima WC, Balestrino D, Forestier C, Cosson P. Two distinct sensing pathways allow recognition of Klebsiella pneumoniae by Dictyostelium amoebae. Cell Microbiol 2013; 16:311-23. [PMID: 24128258 PMCID: PMC4303882 DOI: 10.1111/cmi.12226] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/24/2013] [Accepted: 10/07/2013] [Indexed: 12/24/2022]
Abstract
Recognition of bacteria by metazoans is mediated by receptors that recognize different types of microorganisms and elicit specific cellular responses. The soil amoebae Dictyostelium discoideum feeds upon a variable mixture of environmental bacteria, and it is expected to recognize and adapt to various food sources. To date, however, no bacteria-sensing mechanisms have been described. In this study, we isolated a Dictyostelium mutant (fspA KO) unable to grow in the presence of non-capsulated Klebsiella pneumoniae bacteria, but growing as efficiently as wild-type cells in the presence of other bacteria, such as Bacillus subtilis. fspA KO cells were also unable to respond to K. pneumoniae and more specifically to bacterially secreted folate in a chemokinetic assay, while they responded readily to B. subtilis. Remarkably, both WT and fspA KO cells were able to grow in the presence of capsulated LM21 K. pneumoniae, and responded to purified capsule, indicating that capsule recognition may represent an alternative, FspA-independent mechanism for K. pneumoniae sensing. When LM21 capsule synthesis genes were deleted, growth and chemokinetic response were lost for fspA KO cells, but not for WT cells. Altogether, these results indicate that Dictyostelium amoebae use specific recognition mechanisms to respond to different K. pneumoniae elements.
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Affiliation(s)
- Wanessa C Lima
- Department for Cell Physiology and Metabolism, Centre Medical Universitaire, University of Geneva, 1 rue Michel Servet, 1211, Geneva 4, Switzerland
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21
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Deng Q, Sun M, Yang K, Zhu M, Chen K, Yuan J, Wu M, Huang X. MRP8/14 enhances corneal susceptibility to Pseudomonas aeruginosa Infection by amplifying inflammatory responses. Invest Ophthalmol Vis Sci 2013; 54:1227-34. [PMID: 23299480 DOI: 10.1167/iovs.12-10172] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE We explored the role of myeloid-related protein 8 and 14 (MRP8/14) in Pseudomonas aeruginosa (PA) keratitis. METHODS MRP8/14 mRNA levels in human corneal scrapes and mouse corneas infected by PA were tested using real-time PCR. MRP8/14 protein expression in C57BL/6 (B6) corneas was confirmed using Western blot assay and immunohistochemistry. B6 mice were injected subconjunctivally with siRNA for MRP8/14, and then infected with PA. Bacterial plate counts and myeloperoxidase assays were used to determine the bacterial load and polymorphonuclear neutrophil (PMN) infiltration in infected B6 corneas. Pro-inflammatory cytokine levels in vivo and in vitro were examined with PCR and ELISA. In murine macrophage-like RAW264.7 cells, phagocytosis and bacterial killing were assessed using plate count assays, and reactive oxygen species (ROS) and nitric oxide (NO) levels were tested with flow cytometry and Griess assay, respectively. RESULTS MRP8/14 expression levels were increased significantly in human corneal scrapes and B6 corneas after PA infection. Silencing of MRP8/14 in B6 corneas significantly reduced the severity of corneal disease, bacterial clearance, PMN infiltration, and pro-inflammatory cytokine expression after PA infection. In vitro studies demonstrated further that silencing of MRP8/14 suppressed pro-inflammatory cytokine production, bacterial killing, and ROS production, but not phagocytosis or NO production. CONCLUSIONS Our study demonstrated a dual role for MRP8/14 in bacterial keratitis. Although MRP8/14 promotes bacterial clearance by enhancing ROS production, it functions more importantly as an inflammatory amplifier at the ocular surface by enhancing pro-inflammatory cytokine expression, thus contributing to the corneal susceptibility.
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Affiliation(s)
- Qiuchan Deng
- Department of Immunology, Zhongshan School of Medicine, Institute of Human Virology, Sun Yat-sen University, Guangzhou, China
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22
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Fettucciari K, Quotadamo F, Noce R, Palumbo C, Modesti A, Rosati E, Mannucci R, Bartoli A, Marconi P. Group B Streptococcus (GBS) disrupts by calpain activation the actin and microtubule cytoskeleton of macrophages. Cell Microbiol 2011; 13:859-84. [PMID: 21414124 DOI: 10.1111/j.1462-5822.2011.01584.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Group B Streptococcus (GBS) has evolved several strategies to avoid host defences where macrophages are one of main targets. Since pathogens frequently target the cytoskeleton to evade immune defences, we investigated if GBS manipulates macrophage cytoskeleton. GBS-III-COH31 in a time- and infection ratio-dependent manner induces great macrophage cytoskeleton alterations, causing degradation of several structural and regulatory cytoskeletal proteins. GBS β-haemolysin is involved in cytoskeleton alterations causing plasma membrane permeability defects which allow calcium influx and calpain activation. In fact, cytoskeleton alterations are not induced by GBS-III-COH31 in conditions that suppress β-haemolysin expression/activity and in presence of dipalmitoylphosphatidylcholine (β-haemolysin inhibitor). Calpains, particularly m-calpain, are responsible for GBS-III-COH31-induced cytoskeleton disruption. In fact, the calpain inhibitor PD150606, m-calpain small-interfering-RNA and EGTA which inhibit calpain activation prevented cytoskeleton degradation whereas µ-calpain and other protease inhibitors did not. Finally, calpain inhibition strongly increased the number of viable intracellular GBS-III-COH31, showing that cytoskeleton alterations reduced macrophage phagocytosis. Marked macrophage cytoskeleton alterations are also induced by GBS-III-NEM316 and GBS-V-10/84 through β-haemolysin-mediated plasma membrane permeability defects which allow calpain activation. This study suggests a new GBS strategy to evade macrophage antimicrobial responses based on cytoskeleton disruption by an unusual mechanism mediated by calcium influx and calpain activation.
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Affiliation(s)
- Katia Fettucciari
- General Pathology and Immunology Section, Perugia University, Perugia, Italy.
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23
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Tao L, Pavlova SI, Ji X, Jin L, Spear G. A novel plasmid for delivering genes into mammalian cells with noninvasive food and commensal lactic acid bacteria. Plasmid 2011; 65:8-14. [PMID: 20832422 PMCID: PMC3015009 DOI: 10.1016/j.plasmid.2010.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 08/27/2010] [Accepted: 09/01/2010] [Indexed: 01/06/2023]
Abstract
Using food and commensal lactic acid bacteria (LAB) as vehicles for DNA delivery into epithelial cells is a new strategy for vaccine delivery or gene therapy. However, present methods for DNA delivery with LAB have suffered low efficiency. Our goal was to develop a new system to deliver DNA into epithelial cells with high efficiency using food and commensal LAB. An Escherichia coli-LAB shuttle plasmid, pLKV1, for DNA delivery into eukaryotic cells was constructed. Two reporter plasmids with green and red fluorescent protein genes were also constructed to monitor the uptake of protein and DNA, respectively. Bacteria delivering these reporter plasmids into Caco-2 cells were monitored by fluorescence microscopy. Several methods that weaken the bacterial cell wall prior to co-culture with Caco-2 cells were evaluated for their role in the improvement of gene transfer efficiency. Treating Streptococcus gordonii with penicillin and lysozyme greatly increased its rate of gene delivery to mammalian cells compared to untreated control bacteria, while glycine pretreatment promoted the highest gene transfer rate for Lactococcus lactis. Uptake of green fluorescent bacteria by Caco-2 cells showed that the cell wall-weakening treatment promoted the internalization of the noninvasive bacteria into Caco-2 cells. In conclusion, we have developed a noninvasive system using LAB as a vehicle for vaccine delivery or gene therapy, and tested this system in vitro with Caco-2 cells.
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Affiliation(s)
- Lin Tao
- Department of Oral Biology, College of Dentistry, University of Illinois at Chicago, 801 South Paulina Street, Chicago, IL 60612, USA.
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24
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Hovanessian AG, Soundaramourty C, El Khoury D, Nondier I, Svab J, Krust B. Surface expressed nucleolin is constantly induced in tumor cells to mediate calcium-dependent ligand internalization. PLoS One 2010; 5:e15787. [PMID: 21203423 PMCID: PMC3009748 DOI: 10.1371/journal.pone.0015787] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 11/24/2010] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Nucleolin is one of the major proteins of the nucleolus, but it is also expressed on the cell surface where is serves as a binding protein for variety of ligands implicated in tumorigenesis and angiogenesis. Emerging evidence suggests that the cell-surface expressed nucleolin is a strategic target for an effective and nontoxic cancer therapy. METHODOLOGY/PRINCIPAL FINDINGS By monitoring the expression of nucleolin mRNA, and by measuring the level of nucleolin protein recovered from the surface and nucleus of cells, here we show that the presence of nucleolin at the cell surface is dependent on the constant induction of nucleolin mRNA. Indeed, inhibitors of RNA transcription or translation block expression of surface nucleolin while no apparent effect is observed on the level of nucleolin in the nucleus. The estimated half-life of surface nucleolin is less than one hour, whereas that of nuclear nucleolin is more than 8 hours. Nucleolin mRNA induction is reduced markedly in normal fibroblasts that reach confluence, while it occurs continuously even in post-confluent epithelial tumor cells consistent with their capacity to proliferate without contact inhibition. Interestingly, cold and heat shock induce nucleolin mRNA concomitantly to enhanced mRNA expression of the heat shock protein 70, thus suggesting that surface nucleolin induction also occurs in response to an environmental insult. At the cell surface, one of the main functions of nucleolin is to shuttle specific extracellular ligands by an active transport mechanism, which we show here to be calcium dependent. CONCLUSION/SIGNIFICANCE Our results demonstrate that the expression of surface nucleolin is an early metabolic event coupled with tumor cell proliferation and stress response. The fact that surface nucleolin is constantly and abundantly expressed on the surface of tumor cells, makes them a preferential target for the inhibitory action of anticancer agents that target surface nucleolin.
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Affiliation(s)
- Ara G Hovanessian
- CNRS-Université Paris Descartes, Unité Régulation de la Transcription de Maladies Génétique, Paris, France.
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25
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Abstract
Immune cells kill microbes by engulfing them in a membrane-enclosed compartment, the phagosome. Phagocytosis is initiated when foreign particles bind to receptors on the membrane of phagocytes. The best-studied phagocytic receptors, those for Igs (FcgammaR) and for complement proteins (CR), activate PLC and PLD, resulting in the intracellular production of the Ca(2+)-mobilizing second messengers InsP3 and S1P, respectively. The ensuing release of Ca(2+) from the ER activates SOCE channels in the plasma and/or phagosomal membrane, leading to sustained or oscillatory elevations in cytosolic Ca(2+) concentration. Cytosolic Ca(2+) elevations are required for efficient ingestion of foreign particles by some, but not all, phagocytic receptors and stringently control the subsequent steps involved in the maturation of phagosomes. Ca(2+) is required for the solubilization of the actin meshwork that surrounds nascent phagosomes, for the fusion of phagosomes with granules containing lytic enzymes, and for the assembly and activation of the superoxide-generating NADPH oxidase complex. Furthermore, Ca(2+) entry only occurs at physiological voltages and therefore, requires the activity of proton channels that counteract the depolarizing action of the phagocytic oxidase. The molecules that mediate Ca(2+) ion flux across the phagosomal membrane are still unknown but likely include the ubiquitous SOCE channels and possibly other types of Ca(2+) channels such as LGCC and VGCC. Understanding the molecular basis of the Ca(2+) signals that control phagocytosis might provide new, therapeutic tools against pathogens that subvert phagocytic killing.
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Affiliation(s)
- Paula Nunes
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
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26
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Abstract
Although viruses are simple in structure and composition, their interactions with host cells are complex. Merely to gain entry, animal viruses make use of a repertoire of cellular processes that involve hundreds of cellular proteins. Although some viruses have the capacity to penetrate into the cytosol directly through the plasma membrane, most depend on endocytic uptake, vesicular transport through the cytoplasm, and delivery to endosomes and other intracellular organelles. The internalization may involve clathrin-mediated endocytosis (CME), macropinocytosis, caveolar/lipid raft-mediated endocytosis, or a variety of other still poorly characterized mechanisms. This review focuses on the cell biology of virus entry and the different strategies and endocytic mechanisms used by animal viruses.
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Affiliation(s)
- Jason Mercer
- ETH Zurich, Institute of Biochemistry, CH-8093 Zurich, Switzerland.
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