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Lee JW, Mizuno K, Watanabe H, Lee IH, Tsumita T, Hida K, Yawaka Y, Kitagawa Y, Hasebe A, Iimura T, Kong SW. Enhanced phagocytosis associated with multinucleated microglia via Pyk2 inhibition in an acute β-amyloid infusion model. J Neuroinflammation 2024; 21:196. [PMID: 39107821 PMCID: PMC11301859 DOI: 10.1186/s12974-024-03192-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Accepted: 07/31/2024] [Indexed: 08/10/2024] Open
Abstract
Multinucleated microglia have been observed in contexts associated with infection, inflammation, and aging. Though commonly linked to pathological conditions, the larger cell size of multinucleated microglia might enhance their phagocytic functions, potentially aiding in the clearance of brain debris and suggesting a reassessment of their pathological significance. To assess the phagocytic capacity of multinucleated microglia and its implications for brain debris clearance, we induced their formation by inhibiting Pyk2 activity using the pharmacological inhibitor PF-431396, which triggers cytokinesis regression. Multinucleated microglia demonstrate enhanced phagocytic function, as evidenced by their increased capacity to engulf β-amyloid (Aβ) oligomers. Concurrently, the phosphorylation of Pyk2, induced by Aβ peptide, was diminished upon treatment with a Pyk2 inhibitor (Pyk2-Inh, PF-431396). Furthermore, the increased expression of Lamp1, a lysosomal marker, with Pyk2-inh treatment, suggests an enhancement in proteolytic activity. In vivo, we generated an acute Alzheimer's disease (AD) model by infusing Aβ into the brains of Iba-1 EGFP transgenic (Tg) mice. The administration of the Pyk2-Inh led to an increased migration of microglia toward amyloid deposits in the brains of Iba-1 EGFP Tg mice, accompanied by morphological activation, suggesting a heightened affinity for Aβ. In human microglia, lipopolysaccharide (LPS)-induced inflammatory responses showed that inhibition of Pyk2 signaling significantly reduced the transcription and protein expression of pro-inflammatory markers. These results suggest that Pyk2 inhibition can modulate microglial functions, potentially reducing neuroinflammation and aiding in the clearance of neurodegenerative disease markers. This highlights Pyk2 as a promising target for therapeutic intervention in neurodegenerative diseases.
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Affiliation(s)
- Ji-Won Lee
- Microbiology, Department of Oral Pathobiological Science, Faculty and Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan.
| | - Kaito Mizuno
- Microbiology, Department of Oral Pathobiological Science, Faculty and Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan
- Dentistry for Children and Disabled Persons, Department of Oral Functional Science, Faculty of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan
| | - Haruhisa Watanabe
- Department of Pharmacology, Faculty and Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan
- Oral Diagnosis and Medicine, Department of Oral Pathobiological Science, Faculty of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan
| | - In-Hee Lee
- Computational Health and Informatics Program, Boston Children's Hospital, Boston, MA, 02215, USA
| | - Takuya Tsumita
- Department of Vascular Biology and Molecular Pathology, Faculty and Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan
| | - Kyoko Hida
- Department of Vascular Biology and Molecular Pathology, Faculty and Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan
| | - Yasutaka Yawaka
- Dentistry for Children and Disabled Persons, Department of Oral Functional Science, Faculty of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan
| | - Yoshimasa Kitagawa
- Oral Diagnosis and Medicine, Department of Oral Pathobiological Science, Faculty of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan
| | - Akira Hasebe
- Microbiology, Department of Oral Pathobiological Science, Faculty and Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan
| | - Tadahiro Iimura
- Department of Pharmacology, Faculty and Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan
| | - Sek Won Kong
- Computational Health and Informatics Program, Boston Children's Hospital, Boston, MA, 02215, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
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Sun L, Apweiler M, Tirkey A, Klett D, Normann C, Dietz GPH, Lehner MD, Fiebich BL. Anti-Neuroinflammatory Effects of Ginkgo biloba Extract EGb 761 in LPS-Activated BV2 Microglial Cells. Int J Mol Sci 2024; 25:8108. [PMID: 39125680 PMCID: PMC11312056 DOI: 10.3390/ijms25158108] [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: 05/29/2024] [Revised: 07/12/2024] [Accepted: 07/17/2024] [Indexed: 08/12/2024] Open
Abstract
Inflammatory processes in the brain can exert important neuroprotective functions. However, in neurological and psychiatric disorders, it is often detrimental due to chronic microglial over-activation and the dysregulation of cytokines and chemokines. Growing evidence indicates the emerging yet prominent pathophysiological role of neuroinflammation in the development and progression of these disorders. Despite recent advances, there is still a pressing need for effective therapies, and targeting neuroinflammation is a promising approach. Therefore, in this study, we investigated the anti-neuroinflammatory potential of a marketed and quantified proprietary herbal extract of Ginkgo biloba leaves called EGb 761 (10-500 µg/mL) in BV2 microglial cells stimulated by LPS (10 ng/mL). Our results demonstrate significant inhibition of LPS-induced expression and release of cytokines tumor necrosis factor-α (TNF-α) and Interleukin 6 (IL-6) and chemokines C-X-C motif chemokine ligand 2 (CXCL2), CXCL10, c-c motif chemokine ligand 2 (CCL2) and CCL3 in BV2 microglial cells. The observed effects are possibly mediated by the mitogen-activated protein kinases (MAPK), p38 MAPK and ERK1/2, as well as the protein kinase C (PKC) and the nuclear factor (NF)-κB signaling cascades. The findings of this in vitro study highlight the anti-inflammatory properties of EGb 761 and its therapeutic potential, making it an emerging candidate for the treatment of neuroinflammatory diseases and warranting further research in pre-clinical and clinical settings.
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Affiliation(s)
- Lu Sun
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (L.S.); (M.A.); (A.T.); (D.K.)
| | - Matthias Apweiler
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (L.S.); (M.A.); (A.T.); (D.K.)
| | - Ashwini Tirkey
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (L.S.); (M.A.); (A.T.); (D.K.)
| | - Dominik Klett
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (L.S.); (M.A.); (A.T.); (D.K.)
| | - Claus Normann
- Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany;
| | - Gunnar P. H. Dietz
- Universitätsmedizin Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany;
| | - Martin D. Lehner
- Dr. Willmar Schwabe GmbH & Co. KG, Willmar-Schwabe-Straße 4, 76227 Karlsruhe, Germany;
| | - Bernd L. Fiebich
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (L.S.); (M.A.); (A.T.); (D.K.)
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Sun L, Apweiler M, Normann C, Grathwol CW, Hurrle T, Gräßle S, Jung N, Bräse S, Fiebich BL. Anti-Inflammatory Effects of GPR55 Agonists and Antagonists in LPS-Treated BV2 Microglial Cells. Pharmaceuticals (Basel) 2024; 17:674. [PMID: 38931342 PMCID: PMC11206594 DOI: 10.3390/ph17060674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/19/2024] [Accepted: 05/20/2024] [Indexed: 06/28/2024] Open
Abstract
Chronic inflammation is driven by proinflammatory cytokines such as interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), and chemokines, such as c-c motif chemokine ligand 2 (CCL2), CCL3, C-X-C motif chemokine ligand 2 (CXCL2), and CXCL10. Inflammatory processes of the central nervous system (CNS) play an important role in the pathogenesis of various neurological and psychiatric disorders like Alzheimer's disease, Parkinson's disease, and depression. Therefore, identifying novel anti-inflammatory drugs may be beneficial for treating disorders with a neuroinflammatory background. The G-protein-coupled receptor 55 (GPR55) gained interest due to its role in inflammatory processes and possible involvement in different disorders. This study aims to identify the anti-inflammatory effects of the coumarin-based compound KIT C, acting as an antagonist with inverse agonistic activity at GPR55, in lipopolysaccharide (LPS)-stimulated BV2 microglial cells in comparison to the commercial GPR55 agonist O-1602 and antagonist ML-193. All compounds significantly suppressed IL-6, TNF-α, CCL2, CCL3, CXCL2, and CXCL10 expression and release in LPS-treated BV2 microglial cells. The anti-inflammatory effects of the compounds are partially explained by modulation of the phosphorylation of p38 mitogen-activated protein kinase (MAPK), p42/44 MAPK (ERK 1/2), protein kinase C (PKC) pathways, and the transcription factor nuclear factor (NF)-κB, respectively. Due to its potent anti-inflammatory properties, KIT C is a promising compound for further research and potential use in inflammatory-related disorders.
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Affiliation(s)
- Lu Sun
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany; (L.S.); (M.A.)
| | - Matthias Apweiler
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany; (L.S.); (M.A.)
| | - Claus Normann
- Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany;
| | - Christoph W. Grathwol
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany; (C.W.G.); (T.H.); (S.G.); (N.J.); (S.B.)
| | - Thomas Hurrle
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany; (C.W.G.); (T.H.); (S.G.); (N.J.); (S.B.)
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany
| | - Simone Gräßle
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany; (C.W.G.); (T.H.); (S.G.); (N.J.); (S.B.)
| | - Nicole Jung
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany; (C.W.G.); (T.H.); (S.G.); (N.J.); (S.B.)
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany
| | - Stefan Bräse
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany; (C.W.G.); (T.H.); (S.G.); (N.J.); (S.B.)
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany
| | - Bernd L. Fiebich
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany; (L.S.); (M.A.)
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Sun L, Wilke Saliba S, Apweiler M, Akmermer K, Herlan C, Grathwol C, de Oliveira ACP, Normann C, Jung N, Bräse S, Fiebich BL. Anti-Neuroinflammatory Effects of a Macrocyclic Peptide-Peptoid Hybrid in Lipopolysaccharide-Stimulated BV2 Microglial Cells. Int J Mol Sci 2024; 25:4462. [PMID: 38674048 PMCID: PMC11049839 DOI: 10.3390/ijms25084462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 04/28/2024] Open
Abstract
Inflammation processes of the central nervous system (CNS) play a vital role in the pathogenesis of several neurological and psychiatric disorders like depression. These processes are characterized by the activation of glia cells, such as microglia. Clinical studies showed a decrease in symptoms associated with the mentioned diseases after the treatment with anti-inflammatory drugs. Therefore, the investigation of novel anti-inflammatory drugs could hold substantial potential in the treatment of disorders with a neuroinflammatory background. In this in vitro study, we report the anti-inflammatory effects of a novel hexacyclic peptide-peptoid hybrid in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. The macrocyclic compound X15856 significantly suppressed Interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), c-c motif chemokine ligand 2 (CCL2), CCL3, C-X-C motif chemokine ligand 2 (CXCL2), and CXCL10 expression and release in LPS-treated BV2 microglial cells. The anti-inflammatory effects of the compound are partially explained by the modulation of the phosphorylation of p38 mitogen-activated protein kinases (MAPK), p42/44 MAPK (ERK 1/2), protein kinase C (PKC), and the nuclear factor (NF)-κB, respectively. Due to its remarkable anti-inflammatory properties, this compound emerges as an encouraging option for additional research and potential utilization in disorders influenced by inflammation, such as depression.
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Affiliation(s)
- Lu Sun
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany
| | - Soraya Wilke Saliba
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany
| | - Matthias Apweiler
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany
| | - Kamil Akmermer
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), D-76131 Karlsruhe, Germany; (K.A.); (C.H.); (S.B.)
| | - Claudine Herlan
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), D-76131 Karlsruhe, Germany; (K.A.); (C.H.); (S.B.)
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany
| | - Christoph Grathwol
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany
| | | | - Claus Normann
- Mechanisms of Depression Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany
| | - Nicole Jung
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), D-76131 Karlsruhe, Germany; (K.A.); (C.H.); (S.B.)
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany
| | - Stefan Bräse
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), D-76131 Karlsruhe, Germany; (K.A.); (C.H.); (S.B.)
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany
| | - Bernd L. Fiebich
- Neuroimmunology and Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany
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Francis VI, Liddle C, Camacho E, Kulkarni M, Junior SRS, Harvey JA, Ballou ER, Thomson DD, Brown GD, Hardwick JM, Casadevall A, Witton J, Coelho C. Cryptococcus neoformans rapidly invades the murine brain by sequential breaching of airway and endothelial tissues barriers, followed by engulfment by microglia. mBio 2024; 15:e0307823. [PMID: 38511961 PMCID: PMC11005363 DOI: 10.1128/mbio.03078-23] [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: 11/14/2023] [Accepted: 02/29/2024] [Indexed: 03/22/2024] Open
Abstract
Cryptococcus neoformans causes lethal meningitis and accounts for approximately 10%-15% of AIDS-associated deaths worldwide. There are major gaps in our understanding of how this fungus invades the mammalian brain. To investigate the dynamics of C. neoformans tissue invasion, we mapped fungal localization and host cell interactions in infected brain, lung, and upper airways using mouse models of systemic and airway infection. To enable this, we developed an in situ imaging pipeline capable of measuring large volumes of tissue while preserving anatomical and cellular information by combining thick tissue sections, tissue clarification, and confocal imaging. We confirm high fungal burden in mouse upper airway after nasal inoculation. Yeast in turbinates were frequently titan cells, with faster kinetics than reported in mouse lungs. Importantly, we observed one instance of fungal cells enmeshed in lamina propria of the upper airways, suggesting penetration of airway mucosa as a possible route of tissue invasion and dissemination to the bloodstream. We extend previous literature positing bloodstream dissemination of C. neoformans, by finding viable fungi in the bloodstream of mice a few days after intranasal infection. As early as 24 h post systemic infection, the majority of C. neoformans cells traversed the blood-brain barrier, and were engulfed or in close proximity to microglia. Our work presents a new method for investigating microbial invasion, establishes that C. neoformans can breach multiple tissue barriers within the first days of infection, and demonstrates microglia as the first cells responding to C. neoformans invasion of the brain.IMPORTANCECryptococcal meningitis causes 10%-15% of AIDS-associated deaths globally. Still, brain-specific immunity to cryptococci is a conundrum. By employing innovative imaging, this study reveals what occurs during the first days of infection in brain and in airways. We found that titan cells predominate in upper airways and that cryptococci breach the upper airway mucosa, which implies that, at least in mice, the upper airways are a site for fungal dissemination. This would signify that mucosal immunity of the upper airway needs to be better understood. Importantly, we also show that microglia, the brain-resident macrophages, are the first responders to infection, and microglia clusters are formed surrounding cryptococci. This study opens the field to detailed molecular investigations on airway immune response, how fungus traverses the blood-brain barrier, how microglia respond to infection, and ultimately how microglia monitor the blood-brain barrier to preserve brain function.
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Affiliation(s)
- Vanessa I. Francis
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Corin Liddle
- Bioimaging Facility, University of Exeter, Exeter, United Kingdom
| | - Emma Camacho
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Madhura Kulkarni
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | | | - Jamie A. Harvey
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
| | - Elizabeth R. Ballou
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
| | - Darren D. Thomson
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
| | - Gordon D. Brown
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - J. Marie Hardwick
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Arturo Casadevall
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Jonathan Witton
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Carolina Coelho
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, United Kingdom
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
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Gusev E, Sarapultsev A. Interplay of G-proteins and Serotonin in the Neuroimmunoinflammatory Model of Chronic Stress and Depression: A Narrative Review. Curr Pharm Des 2024; 30:180-214. [PMID: 38151838 DOI: 10.2174/0113816128285578231218102020] [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: 10/04/2023] [Accepted: 11/29/2023] [Indexed: 12/29/2023]
Abstract
INTRODUCTION This narrative review addresses the clinical challenges in stress-related disorders such as depression, focusing on the interplay between neuron-specific and pro-inflammatory mechanisms at the cellular, cerebral, and systemic levels. OBJECTIVE We aim to elucidate the molecular mechanisms linking chronic psychological stress with low-grade neuroinflammation in key brain regions, particularly focusing on the roles of G proteins and serotonin (5-HT) receptors. METHODS This comprehensive review of the literature employs systematic, narrative, and scoping review methodologies, combined with systemic approaches to general pathology. It synthesizes current research on shared signaling pathways involved in stress responses and neuroinflammation, including calcium-dependent mechanisms, mitogen-activated protein kinases, and key transcription factors like NF-κB and p53. The review also focuses on the role of G protein-coupled neurotransmitter receptors (GPCRs) in immune and pro-inflammatory responses, with a detailed analysis of how 13 of 14 types of human 5-HT receptors contribute to depression and neuroinflammation. RESULTS The review reveals a complex interaction between neurotransmitter signals and immunoinflammatory responses in stress-related pathologies. It highlights the role of GPCRs and canonical inflammatory mediators in influencing both pathological and physiological processes in nervous tissue. CONCLUSION The proposed Neuroimmunoinflammatory Stress Model (NIIS Model) suggests that proinflammatory signaling pathways, mediated by metabotropic and ionotropic neurotransmitter receptors, are crucial for maintaining neuronal homeostasis. Chronic mental stress can disrupt this balance, leading to increased pro-inflammatory states in the brain and contributing to neuropsychiatric and psychosomatic disorders, including depression. This model integrates traditional theories on depression pathogenesis, offering a comprehensive understanding of the multifaceted nature of the condition.
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Affiliation(s)
- Evgenii Gusev
- Laboratory of Inflammation Immunology, Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Science, Ekaterinburg 620049, Russia
- Russian-Chinese Education and Research Center of System Pathology, South Ural State University, Chelyabinsk 454080, Russia
| | - Alexey Sarapultsev
- Russian-Chinese Education and Research Center of System Pathology, South Ural State University, Chelyabinsk 454080, Russia
- Laboratory of Immunopathophysiology, Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Science, Ekaterinburg 620049, Russia
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Francis VI, Liddle C, Camacho E, Kulkarni M, Junior SRS, Harvey JA, Ballou ER, Thomson DD, Hardwick JM, Casadevall A, Witton J, Coelho C. Cryptococcus neoformans rapidly invades the murine brain by sequential breaching of airway and endothelial tissues barriers, followed by engulfment by microglia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.13.564824. [PMID: 38014111 PMCID: PMC10680653 DOI: 10.1101/2023.11.13.564824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The fungus Cryptococcus neoformans causes lethal meningitis in humans with weakened immune systems and is estimated to account for 10-15% of AIDS-associated deaths worldwide. There are major gaps in our understanding of how this environmental fungus evades the immune system and invades the mammalian brain before the onset of overt symptoms. To investigate the dynamics of C. neoformans tissue invasion, we mapped early fungal localisation and host cell interactions at early times in infected brain, lung, and upper airways using mouse models of systemic and airway infection. To enable this, we developed an in situ imaging pipeline capable of measuring large volumes of tissue while preserving anatomical and cellular information by combining thick tissue sections, tissue clarification, and confocal imaging. Made possible by these techniques, we confirm high fungal burden in mouse upper airway turbinates after nasal inoculation. Surprisingly, most yeasts in turbinates were titan cells, indicating this microenvironment enables titan cell formation with faster kinetics than reported in mouse lungs. Importantly, we observed one instance of fungal cells enmeshed in lamina propria of upper airways, suggesting penetration of airway mucosa as a possible route of tissue invasion and dissemination to the bloodstream. We extend previous literature positing bloodstream dissemination of C. neoformans, via imaging C. neoformans within blood vessels of mouse lungs and finding viable fungi in the bloodstream of mice a few days after intranasal infection, suggesting that bloodstream access can occur via lung alveoli. In a model of systemic cryptococcosis, we show that as early as 24 h post infection, majority of C. neoformans cells traversed the blood-brain barrier, and are engulfed or in close proximity to microglia. Our work establishes that C. neoformans can breach multiple tissue barriers within the first days of infection. This work presents a new method for investigating cryptococcal invasion mechanisms and demonstrates microglia as the primary cells responding to C. neoformans invasion.
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Affiliation(s)
- Vanessa I Francis
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, EX4 4QD, UK
- Faculty of Health and Life Sciences, University of Exeter, EX4 4QD, UK
| | - Corin Liddle
- Bioimaging Facility, University of Exeter, Exeter, EX4 4QD, UK
| | - Emma Camacho
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Madhura Kulkarni
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Samuel R S Junior
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Jamie A Harvey
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, EX4 4QD, UK
| | - Elizabeth R Ballou
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, EX4 4QD, UK
| | - Darren D Thomson
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, EX4 4QD, UK
| | - J Marie Hardwick
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Arturo Casadevall
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Jonathan Witton
- Faculty of Health and Life Sciences, University of Exeter, EX4 4QD, UK
| | - Carolina Coelho
- MRC Centre for Medical Mycology at University of Exeter, University of Exeter, Exeter, EX4 4QD, UK
- Faculty of Health and Life Sciences, University of Exeter, EX4 4QD, UK
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Sfera A, Rahman L, Zapata-Martín Del Campo CM, Kozlakidis Z. Long COVID as a Tauopathy: Of "Brain Fog" and "Fusogen Storms". Int J Mol Sci 2023; 24:12648. [PMID: 37628830 PMCID: PMC10454863 DOI: 10.3390/ijms241612648] [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: 07/13/2023] [Revised: 08/04/2023] [Accepted: 08/06/2023] [Indexed: 08/27/2023] Open
Abstract
Long COVID, also called post-acute sequelae of SARS-CoV-2, is characterized by a multitude of lingering symptoms, including impaired cognition, that can last for many months. This symptom, often called "brain fog", affects the life quality of numerous individuals, increasing medical complications as well as healthcare expenditures. The etiopathogenesis of SARS-CoV-2-induced cognitive deficit is unclear, but the most likely cause is chronic inflammation maintained by a viral remnant thriving in select body reservoirs. These viral sanctuaries are likely comprised of fused, senescent cells, including microglia and astrocytes, that the pathogen can convert into neurotoxic phenotypes. Moreover, as the enteric nervous system contains neurons and glia, the virus likely lingers in the gastrointestinal tract as well, accounting for the intestinal symptoms of long COVID. Fusogens are proteins that can overcome the repulsive forces between cell membranes, allowing the virus to coalesce with host cells and enter the cytoplasm. In the intracellular compartment, the pathogen hijacks the actin cytoskeleton, fusing host cells with each other and engendering pathological syncytia. Cell-cell fusion enables the virus to infect the healthy neighboring cells. We surmise that syncytia formation drives cognitive impairment by facilitating the "seeding" of hyperphosphorylated Tau, documented in COVID-19. In our previous work, we hypothesized that the SARS-CoV-2 virus induces premature endothelial senescence, increasing the permeability of the intestinal and blood-brain barrier. This enables the migration of gastrointestinal tract microbes and/or their components into the host circulation, eventually reaching the brain where they may induce cognitive dysfunction. For example, translocated lipopolysaccharides or microbial DNA can induce Tau hyperphosphorylation, likely accounting for memory problems. In this perspective article, we examine the pathogenetic mechanisms and potential biomarkers of long COVID, including microbial cell-free DNA, interleukin 22, and phosphorylated Tau, as well as the beneficial effect of transcutaneous vagal nerve stimulation.
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Affiliation(s)
- Adonis Sfera
- Paton State Hospital, 3102 Highland Ave, Patton, CA 92369, USA
- School of Behavioral Health, Loma Linda University, 11139 Anderson St., Loma Linda, CA 92350, USA
- Department of Psychiatry, University of California, Riverside 900 University Ave, Riverside, CA 92521, USA
| | - Leah Rahman
- Department of Neuroscience, University of Oregon, 222 Huestis Hall, Eugene, OR 97401, USA
| | | | - Zisis Kozlakidis
- International Agency for Research on Cancer, World Health Organization, 69000 Lyon, France
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9
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Phosphatidylserine in the Nervous System: Cytoplasmic Regulator of the AKT and PKC Signaling Pathways and Extracellular "Eat-Me" Signal in Microglial Phagocytosis. Mol Neurobiol 2023; 60:1050-1066. [PMID: 36401705 DOI: 10.1007/s12035-022-03133-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 11/08/2022] [Indexed: 11/21/2022]
Abstract
Phosphatidylserine (PtdSer) is an important anionic phospholipid found in eukaryotic cells and has been proven to serve as a beneficial factor in the treatment of neurodegenerative diseases. PtdSer resides in the inner leaflet of the plasma membrane, where it is involved in regulating the AKT and PKC signaling pathways; however, it becomes exposed to the extracellular leaflet during neurodevelopmental processes and neurodegenerative diseases, participating in microglia-mediated synaptic and neuronal phagocytosis. In this paper, we review several characteristics of PtdSer, including the synthesis and translocation of PtdSer, the functions of cytoplasmic and exposed PtdSer, and different PtdSer-detection materials used to further understand the role of PtdSer in the nervous system.
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10
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Long COVID and the Neuroendocrinology of Microbial Translocation Outside the GI Tract: Some Treatment Strategies. ENDOCRINES 2022. [DOI: 10.3390/endocrines3040058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Similar to previous pandemics, COVID-19 has been succeeded by well-documented post-infectious sequelae, including chronic fatigue, cough, shortness of breath, myalgia, and concentration difficulties, which may last 5 to 12 weeks or longer after the acute phase of illness. Both the psychological stress of SARS-CoV-2 infection and being diagnosed with COVID-19 can upregulate cortisol, a stress hormone that disrupts the efferocytosis effectors, macrophages, and natural killer cells, leading to the excessive accumulation of senescent cells and disruption of biological barriers. This has been well-established in cancer patients who often experience unrelenting fatigue as well as gut and blood–brain barrier dysfunction upon treatment with senescence-inducing radiation or chemotherapy. In our previous research from 2020 and 2021, we linked COVID-19 to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) via angiotensin II upregulation, premature endothelial senescence, intestinal barrier dysfunction, and microbial translocation from the gastrointestinal tract into the systemic circulation. In 2021 and 2022, these hypotheses were validated and SARS-CoV-2-induced cellular senescence as well as microbial translocation were documented in both acute SARS-CoV-2 infection, long COVID, and ME/CFS, connecting intestinal barrier dysfunction to disabling fatigue and specific infectious events. The purpose of this narrative review is to summarize what is currently known about host immune responses to translocated gut microbes and how these responses relate to fatiguing illnesses, including long COVID. To accomplish this goal, we examine the role of intestinal and blood–brain barriers in long COVID and other illnesses typified by chronic fatigue, with a special emphasis on commensal microbes functioning as viral reservoirs. Furthermore, we discuss the role of SARS-CoV-2/Mycoplasma coinfection in dysfunctional efferocytosis, emphasizing some potential novel treatment strategies, including the use of senotherapeutic drugs, HMGB1 inhibitors, Toll-like receptor 4 (TLR4) blockers, and membrane lipid replacement.
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11
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Irie M, Itoh J, Matsuzawa A, Ikawa M, Kiyonari H, Kihara M, Suzuki T, Hiraoka Y, Ishino F, Kaneko-Ishino T. Retrovirus-derived RTL5 and RTL6 genes are novel constituents of the innate immune system in the eutherian brain. Development 2022; 149:dev200976. [PMID: 36162816 PMCID: PMC9641642 DOI: 10.1242/dev.200976] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 08/14/2022] [Indexed: 09/26/2023]
Abstract
Retrotransposon Gag-like 5 [RTL5, also known as sushi-ichi-related retrotransposon homolog 8 (SIRH8)] and RTL6 (also known as SIRH3) are eutherian-specific genes presumably derived from a retrovirus and phylogenetically related to each other. They, respectively, encode a strongly acidic and extremely basic protein, and are well conserved among the eutherians. Here, we report that RTL5 and RTL6 are microglial genes with roles in the front line of innate brain immune response. Venus and mCherry knock-in mice exhibited expression of RTL5-mCherry and RTL6-Venus fusion proteins in microglia and appeared as extracellular dots and granules in the central nervous system. These proteins display a rapid response to pathogens such as lipopolysaccharide (LPS), double-stranded (ds) RNA analog and non-methylated CpG DNA, acting both cooperatively and/or independently. Experiments using Rtl6 or Rtl5 knockout mice provided additional evidence that RTL6 and RTL5 act as factors against LPS and dsRNA, respectively, in the brain, providing the first demonstration that retrovirus-derived genes play a role in the eutherian innate immune system. Finally, we propose a model emphasizing the importance of extra-embryonic tissues as the origin site of retrovirus-derived genes. This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Masahito Irie
- Faculty of Nursing, School of Medicine, Tokai University, Kanagawa 259-1193, Japan
- Department of Epigenetics, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo 113-8510, Japan
| | - Johbu Itoh
- Department of Pathology, School of Medicine, Tokai University, Kanagawa 259-1193, Japan
| | - Ayumi Matsuzawa
- Department of Epigenetics, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo 113-8510, Japan
- Department of Genomic Function and Diversity, MRI, TMDU, Tokyo 113-8510, Japan
| | - Masahito Ikawa
- Animal Resource Center for Infectious Diseases, Research Institute for Microbial Diseases, Osaka 565-0871, Japan
| | - Hiroshi Kiyonari
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan
| | - Miho Kihara
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan
| | - Toru Suzuki
- Laboratory of Genome Editing for Biomedical Research, MRI, TMDU, Tokyo 113-8510, Japan
| | - Yuichi Hiraoka
- Laboratory of Genome Editing for Biomedical Research, MRI, TMDU, Tokyo 113-8510, Japan
- Laboratory of Molecular Neuroscience, MRI, TMDU, Tokyo 113-8510, Japan
| | - Fumitoshi Ishino
- Department of Epigenetics, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo 113-8510, Japan
| | - Tomoko Kaneko-Ishino
- Faculty of Nursing, School of Medicine, Tokai University, Kanagawa 259-1193, Japan
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12
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Moca EN, Lecca D, Hope KT, Etienne F, Schaler AW, Espinoza K, Chappell MS, Gray DT, Tweedie D, Sidhu S, Masukawa L, Sitoy H, Mathew R, Saban DR, Greig NH, De Biase LM. Microglia Drive Pockets of Neuroinflammation in Middle Age. J Neurosci 2022; 42:3896-3918. [PMID: 35396327 PMCID: PMC9097782 DOI: 10.1523/jneurosci.1922-21.2022] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 02/18/2022] [Accepted: 03/14/2022] [Indexed: 11/21/2022] Open
Abstract
During aging, microglia produce inflammatory factors, show reduced tissue surveillance, altered interactions with synapses, and prolonged responses to CNS insults, positioning these cells to have profound impact on the function of nearby neurons. We and others recently showed that microglial attributes differ significantly across brain regions in young adult mice. However, the degree to which microglial properties vary during aging is largely unexplored. Here, we analyze and manipulate microglial aging within the basal ganglia, brain circuits that exhibit prominent regional microglial heterogeneity and where neurons are vulnerable to functional decline and neurodegenerative disease. In male and female mice, we demonstrate that VTA and SNc microglia exhibit unique and premature responses to aging, compared with cortex and NAc microglia. This is associated with localized VTA/SNc neuroinflammation that may compromise synaptic function as early as middle age. Surprisingly, systemic inflammation, local neuron death, and astrocyte aging do not appear to underlie these early aging responses of VTA and SNc microglia. Instead, we found that microglial lysosome status was tightly linked to early aging of VTA microglia. Microglial ablation/repopulation normalized VTA microglial lysosome swelling and suppressed increases in VTA microglial density during aging. In contrast, CX3CR1 receptor KO exacerbated VTA microglial lysosome rearrangements and VTA microglial proliferation during aging. Our findings reveal a previously unappreciated regional variation in onset and magnitude of microglial proliferation and inflammatory factor production during aging and highlight critical links between microglial lysosome status and local microglial responses to aging.SIGNIFICANCE STATEMENT Microglia are CNS cells that are equipped to regulate neuronal health and function throughout the lifespan. We reveal that microglia in select brain regions begin to proliferate and produce inflammatory factors in late middle age, months before microglia in other brain regions. These findings demonstrate that CNS neuroinflammation during aging is not uniform. Moreover, they raise the possibility that local microglial responses to aging play a critical role in determining which populations of neurons are most vulnerable to functional decline and neurodegenerative disease.
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Affiliation(s)
- Eric N Moca
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Daniela Lecca
- Intramural Research Program, National Institute on Aging, Baltimore, Maryland 21224
| | - Keenan T Hope
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Fanny Etienne
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Ari W Schaler
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Katherine Espinoza
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Megan S Chappell
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Daniel T Gray
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - David Tweedie
- Intramural Research Program, National Institute on Aging, Baltimore, Maryland 21224
| | - Shanaya Sidhu
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Lindsay Masukawa
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Hannah Sitoy
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Rose Mathew
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina 27710
| | - Daniel R Saban
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina 27710
| | - Nigel H Greig
- Intramural Research Program, National Institute on Aging, Baltimore, Maryland 21224
| | - Lindsay M De Biase
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
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13
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PIDD1 in cell cycle control, sterile inflammation and cell death. Biochem Soc Trans 2022; 50:813-824. [PMID: 35343572 PMCID: PMC9162469 DOI: 10.1042/bst20211186] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/06/2022] [Accepted: 03/08/2022] [Indexed: 02/06/2023]
Abstract
The death fold domain-containing protein PIDD1 has recently attracted renewed attention as a regulator of the orphan cell death-related protease, Caspase-2. Caspase-2 can activate p53 to promote cell cycle arrest in response to centrosome aberrations, and its activation requires formation of the PIDDosome multi-protein complex containing multimers of PIDD1 and the adapter RAIDD/CRADD at its core. However, PIDD1 appears to be able to engage with multiple client proteins to promote an even broader range of biological responses, such as NF-κB activation, translesion DNA synthesis or cell death. PIDD1 shows features of inteins, a class of self-cleaving proteins, to create different polypeptides from a common precursor protein that allow it to serve these diverse functions. This review summarizes structural information and molecular features as well as recent experimental advances that highlight the potential pathophysiological roles of this unique death fold protein to highlight its drug-target potential.
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14
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Osorio C, Sfera A, Anton JJ, Thomas KG, Andronescu CV, Li E, Yahia RW, Avalos AG, Kozlakidis Z. Virus-Induced Membrane Fusion in Neurodegenerative Disorders. Front Cell Infect Microbiol 2022; 12:845580. [PMID: 35531328 PMCID: PMC9070112 DOI: 10.3389/fcimb.2022.845580] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 03/01/2022] [Indexed: 12/15/2022] Open
Abstract
A growing body of epidemiological and research data has associated neurotropic viruses with accelerated brain aging and increased risk of neurodegenerative disorders. Many viruses replicate optimally in senescent cells, as they offer a hospitable microenvironment with persistently elevated cytosolic calcium, abundant intracellular iron, and low interferon type I. As cell-cell fusion is a major driver of cellular senescence, many viruses have developed the ability to promote this phenotype by forming syncytia. Cell-cell fusion is associated with immunosuppression mediated by phosphatidylserine externalization that enable viruses to evade host defenses. In hosts, virus-induced immune dysfunction and premature cellular senescence may predispose to neurodegenerative disorders. This concept is supported by novel studies that found postinfectious cognitive dysfunction in several viral illnesses, including human immunodeficiency virus-1, herpes simplex virus-1, and SARS-CoV-2. Virus-induced pathological syncytia may provide a unified framework for conceptualizing neuronal cell cycle reentry, aneuploidy, somatic mosaicism, viral spreading of pathological Tau and elimination of viable synapses and neurons by neurotoxic astrocytes and microglia. In this narrative review, we take a closer look at cell-cell fusion and vesicular merger in the pathogenesis of neurodegenerative disorders. We present a "decentralized" information processing model that conceptualizes neurodegeneration as a systemic illness, triggered by cytoskeletal pathology. We also discuss strategies for reversing cell-cell fusion, including, TMEM16F inhibitors, calcium channel blockers, senolytics, and tubulin stabilizing agents. Finally, going beyond neurodegeneration, we examine the potential benefit of harnessing fusion as a therapeutic strategy in regenerative medicine.
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Affiliation(s)
- Carolina Osorio
- Department of Psychiatry, Loma Linda University, Loma Linda, CA, United States
| | - Adonis Sfera
- Department of Psychiatry, Loma Linda University, Loma Linda, CA, United States
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Jonathan J. Anton
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Karina G. Thomas
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Christina V. Andronescu
- Medical Anthropology – Department of Anthropology, Stanford University, Stanford, CA, United States
| | - Erica Li
- School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Rayan W. Yahia
- School of Medicine, University of California, Riverside, Riverside, CA, United States
| | - Andrea García Avalos
- Universidad Nacional Autónoma de México (UNAM), Facultad de Medicina Campus, Ciudad de Mexico, Mexico
| | - Zisis Kozlakidis
- International Agency for Research on Cancer (IARC), Lyon, France
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15
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Cancer cells employ an evolutionarily conserved polyploidization program to resist therapy. Semin Cancer Biol 2020; 81:145-159. [PMID: 33276091 DOI: 10.1016/j.semcancer.2020.11.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 12/24/2022]
Abstract
Unusually large cancer cells with abnormal nuclei have been documented in the cancer literature since 1858. For more than 100 years, they have been generally disregarded as irreversibly senescent or dying cells, too morphologically misshapen and chromatin too disorganized to be functional. Cell enlargement, accompanied by whole genome doubling or more, is observed across organisms, often associated with mitigation strategies against environmental change, severe stress, or the lack of nutrients. Our comparison of the mechanisms for polyploidization in other organisms and non-transformed tissues suggest that cancer cells draw from a conserved program for their survival, utilizing whole genome doubling and pausing proliferation to survive stress. These polyaneuploid cancer cells (PACCs) are the source of therapeutic resistance, responsible for cancer recurrence and, ultimately, cancer lethality.
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16
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Gilchrist SE, Goudarzi S, Hafizi S. Gas6 Inhibits Toll-Like Receptor-Mediated Inflammatory Pathways in Mouse Microglia via Axl and Mer. Front Cell Neurosci 2020; 14:576650. [PMID: 33192322 PMCID: PMC7584110 DOI: 10.3389/fncel.2020.576650] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/08/2020] [Indexed: 12/30/2022] Open
Abstract
Background: Microglia are well known key regulators of neuroinflammation which feature in multiple neurodegenerative disorders. These cells survey the CNS and, under inflammatory conditions, become "activated" through stimulation of toll-like receptors (TLRs), resulting in changes in morphology and production and release of cytokines. In the present study, we examined the roles of the related TAM receptors, Mer and Axl, and of their ligand, Gas6, in the regulation of microglial pro-inflammatory TNF-α production and microglial morphology. Methods: Primary cultures of murine microglia of wild-type (WT), Mer-/- and Axl-/- backgrounds were stimulated by the TLR4 agonist, lipopolysaccharide (LPS) with or without pre-treatment with Gas6. Gene expression of TNF-α, Mer, and Axl was examined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA) was used to measure TNF-α release from microglia. Immunofluorescence staining of β-actin and the microglial marker Iba1 was performed to reveal microglial morphological changes, with cellular characteristics (area, perimeter, Feret's diameter, minimum Feret, roundness, and aspect ratio) being quantified using ImageJ software. Results: Under basal conditions, TNF-α gene expression was significantly lower in Axl-/- microglia compared to WT cells. However, all microglial cultures robustly responded to LPS stimulation with the upregulation of TNF-α expression to similar degrees. Furthermore, Mer receptor expression was less responsive to LPS stimulation when in Axl knockout cells. The presence of Gas6 consistently inhibited the LPS-induced upregulation of TNF-α in WT, Mer-/- and Axl-/- microglia. Moreover, Gas6 also inhibited LPS-induced changes in the microglial area, perimeter length, and cell roundness in wild-type cells. Conclusion: Gas6 can negatively regulate the microglial pro-inflammatory response to LPS as well as via stimulation of other TLRs, acting through either of the TAM receptors, Axl and Mer. This finding indicates an interaction between TLR and TAM receptor signaling pathways and reveals an anti-inflammatory role for the TAM ligand, Gas6, which could have therapeutic potential.
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Affiliation(s)
- Shannon E Gilchrist
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Salman Goudarzi
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Sassan Hafizi
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
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17
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Sierra-Torre V, Plaza-Zabala A, Bonifazi P, Abiega O, Díaz-Aparicio I, Tegelberg S, Lehesjoki AE, Valero J, Sierra A. Microglial phagocytosis dysfunction in the dentate gyrus is related to local neuronal activity in a genetic model of epilepsy. Epilepsia 2020; 61:2593-2608. [PMID: 32940364 PMCID: PMC7756777 DOI: 10.1111/epi.16692] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/20/2020] [Accepted: 08/20/2020] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Microglial phagocytosis of apoptotic cells is an essential component of the brain regenerative response during neurodegeneration. Whereas it is very efficient in physiological conditions, it is impaired in mouse and human mesial temporal lobe epilepsy, and now we extend our studies to a model of progressive myoclonus epilepsy type 1 in mice lacking cystatin B (CSTB). METHODS We used confocal imaging and stereology-based quantification of apoptosis and phagocytosis of the hippocampus of Cstb knockout (KO) mice, an in vitro model of phagocytosis and siRNAs to acutely reduce Cstb expression, and a virtual three-dimensional (3D) model to analyze the physical relationship between apoptosis, phagocytosis, and active hippocampal neurons. RESULTS Microglial phagocytosis was impaired in the hippocampus of Cstb KO mice at 1 month of age, when seizures arise and hippocampal atrophy begins. This impairment was not related to the lack of Cstb in microglia alone, as shown by in vitro experiments with microglial Cstb depletion. The phagocytosis impairment was also unrelated to seizures, as it was also present in Cstb KO mice at postnatal day 14, before seizures begin. Importantly, phagocytosis impairment was restricted to the granule cell layer and spared the subgranular zone, where there are no active neurons. Furthermore, apoptotic cells (both phagocytosed and not phagocytosed) in Cstb-deficient mice were at close proximity to active cFos+ neurons, and a virtual 3D model demonstrated that the physical relationship between apoptotic cells and cFos+ neurons was specific for Cstb KO mice. SIGNIFICANCE These results suggest a complex crosstalk between apoptosis, phagocytosis, and neuronal activity, hinting that local neuronal activity could be related to phagocytosis dysfunction in Cstb KO mice. Overall, these data suggest that phagocytosis impairment is an early feature of hippocampal damage in epilepsy and opens novel therapeutic approaches for epileptic patients based on targeting microglial phagocytosis.
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Affiliation(s)
- Virginia Sierra-Torre
- Achucarro Basque Center for Neuroscience, Science Park University of the Basque Country EHU/UPV, Leioa, Spain.,Department of Neuroscience, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Ainhoa Plaza-Zabala
- Achucarro Basque Center for Neuroscience, Science Park University of the Basque Country EHU/UPV, Leioa, Spain
| | - Paolo Bonifazi
- Ikerbasque Foundation, Bilbao, Spain.,Biocruces Health Research Institute, Barakaldo, Spain
| | - Oihane Abiega
- Achucarro Basque Center for Neuroscience, Science Park University of the Basque Country EHU/UPV, Leioa, Spain.,Department of Neuroscience, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Irune Díaz-Aparicio
- Achucarro Basque Center for Neuroscience, Science Park University of the Basque Country EHU/UPV, Leioa, Spain.,Department of Neuroscience, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Saara Tegelberg
- Folkhälsan Research Center, University of Helsinki, Helsinki, Finland
| | | | - Jorge Valero
- Achucarro Basque Center for Neuroscience, Science Park University of the Basque Country EHU/UPV, Leioa, Spain.,Department of Neuroscience, University of the Basque Country UPV/EHU, Leioa, Spain.,Ikerbasque Foundation, Bilbao, Spain
| | - Amanda Sierra
- Achucarro Basque Center for Neuroscience, Science Park University of the Basque Country EHU/UPV, Leioa, Spain.,Department of Neuroscience, University of the Basque Country UPV/EHU, Leioa, Spain.,Ikerbasque Foundation, Bilbao, Spain
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18
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Emulsified silicone oil is taken up by and induces pro-inflammatory response in primary retinal microglia. Graefes Arch Clin Exp Ophthalmol 2020; 258:1965-1974. [PMID: 32500303 PMCID: PMC7438289 DOI: 10.1007/s00417-020-04763-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 04/07/2020] [Accepted: 05/20/2020] [Indexed: 12/21/2022] Open
Abstract
Purpose Silicone oil is used as endotamponade in combination with vitrectomy. Thinning of retinal layers and loss of retinal cells under silicone oil use have been found. Here, we investigate the influence of silicone oil on primary microglia cells. Methods Primary microglia cells were prepared from the porcine retina. Microglia identity was assessed with Iba1 staining. Silicone oil was emulsified by sonification. Cell morphology and silicone oil uptake were evaluated by light microscopy after Coomassie blue staining. Cytokine secretion was evaluated with ELISA. Toxicity of silicone oil on microglia and toxic effect of silicone oil–treated microglia on neuronal cell line PC12 were evaluated by MTT or WST assay, respectively. Results Microglia took up silicone oil droplets after 72 h of incubation. Silicone oil induced no toxicity but increased the metabolism in microglial cells. In addition, the secretion of IL-6 and IL-8, but not of IL-1ß or TNF-α, was induced. Silicone oil–treated microglia did not exert any neurotoxic effect on differentiated PC12 cells but induced an increase in metabolism. Conclusion Emulsified silicone oil changes the activity level of microglia and induces the secretion of IL-6 and IL-8. Neurotoxicity is not induced. Further experiments are required to investigate the long-term effect of silicone oil on microglia and their consequent effect on neuronal cells.
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19
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Wang L, Gong X, Liu Y, Du T, Zhang Z, Zhang T, Wang X. CD200 maintains the region-specific phenotype of microglia in the midbrain and its role in Parkinson's disease. Glia 2020; 68:1874-1890. [PMID: 32112601 DOI: 10.1002/glia.23811] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 01/23/2020] [Accepted: 02/18/2020] [Indexed: 12/21/2022]
Abstract
Microglia are a specialized population of tissue macrophages in the mammalian brain. Microglial phenotype is tightly regulated by local environmental factors, although little is known about these factors and their region-preferred roles in regulating local neuroinflammatory responses. We hypothesized that microglia in different brain regions respond differently to neuroinflammatory stimulation and that CD200, an anti-inflammatory protein mainly originated from neurons, acts as a local cue inhibiting microglia activation in the midbrain. We utilized a CD200-deficient mouse line to analyze the phenotypic role of CD200 in the regulation of normal neuron-microglia homeostasis in the midbrain and in the dopaminergic degeneration in an α-synuclein overexpression model of PD. We found that systemic administration of an endotoxin lipopolysaccharide induced a region-preferred change in CD200 expression in the midbrain. Similarly, CD200-/- mice showed a regional preference in an enhancement of microglia activation and baseline inflammatory levels in the midbrain and dopamine neuron loss in the substantia nigra (SN). In a mouse model of Parkinson's disease (PD) induced by rAAV-hSYN injection into the SN, CD200-/- mice showed more dopamine neuron loss in the SN than wild type mice. Activation of CD200 receptors with a CD200 fusion protein alleviated the neuroinflammation and neuronal death in the SN of PD mice. These findings demonstrate that CD200 is essential for the midbrain homeostasis and acts as a critical local regulator in controlling microglial properties related to the PD pathogenesis.
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Affiliation(s)
- Le Wang
- Department of Neurobiology, Center of Parkinson Disease Beijing Institute for Brain Disorders, Beijing Key Laboratory on Parkinson Disease, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| | - Xiaoli Gong
- Department of Physiology and Pathophysiology, Capital Medical University, Beijing, China
| | - Yang Liu
- Department of Neurobiology, Center of Parkinson Disease Beijing Institute for Brain Disorders, Beijing Key Laboratory on Parkinson Disease, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| | - Tianshu Du
- Department of Neurobiology, Center of Parkinson Disease Beijing Institute for Brain Disorders, Beijing Key Laboratory on Parkinson Disease, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| | - Zhen Zhang
- Department of Neurobiology, Center of Parkinson Disease Beijing Institute for Brain Disorders, Beijing Key Laboratory on Parkinson Disease, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| | - Ting Zhang
- Department of Neurobiology, Center of Parkinson Disease Beijing Institute for Brain Disorders, Beijing Key Laboratory on Parkinson Disease, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| | - Xiaomin Wang
- Department of Neurobiology, Center of Parkinson Disease Beijing Institute for Brain Disorders, Beijing Key Laboratory on Parkinson Disease, Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
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Cockram TOJ, Puigdellívol M, Brown GC. Calreticulin and Galectin-3 Opsonise Bacteria for Phagocytosis by Microglia. Front Immunol 2019; 10:2647. [PMID: 31781126 PMCID: PMC6861381 DOI: 10.3389/fimmu.2019.02647] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/25/2019] [Indexed: 12/18/2022] Open
Abstract
Opsonins are soluble, extracellular proteins, released by activated immune cells, and when bound to a target cell, can induce phagocytes to phagocytose the target cell. There are three known classes of opsonin: antibodies, complement factors and secreted pattern recognition receptors, but these have limited access to the brain. We identify here two novel opsonins of bacteria, calreticulin, and galectin-3 (both lectins that can bind lipopolysaccharide), which were released by microglia (brain-resident macrophages) when activated by bacterial lipopolysaccharide. Calreticulin and galectin-3 both bound to Escherichia coli, and when bound increased phagocytosis of these bacteria by microglia. Furthermore, lipopolysaccharide-induced microglial phagocytosis of E. coli bacteria was partially inhibited by: sugars, an anti-calreticulin antibody, a blocker of the calreticulin phagocytic receptor LRP1, a blocker of the galectin-3 phagocytic receptor MerTK, or simply removing factors released from the microglia, indicating this phagocytosis is dependent on extracellular calreticulin and galectin-3. Thus, calreticulin and galectin-3 are opsonins, released by activated microglia to promote clearance of bacteria. This innate immune response of microglia may help clear bacterial infections of the brain.
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Affiliation(s)
- Tom O J Cockram
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Mar Puigdellívol
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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21
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Shtaya A, Bridges LR, Esiri MM, Lam‐Wong J, Nicoll JAR, Boche D, Hainsworth AH. Rapid neuroinflammatory changes in human acute intracerebral hemorrhage. Ann Clin Transl Neurol 2019; 6:1465-1479. [PMID: 31402627 PMCID: PMC6689697 DOI: 10.1002/acn3.50842] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/19/2019] [Accepted: 06/25/2019] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE Spontaneous intracerebral hemorrhage (ICH) is the commonest form of hemorrhagic stroke and is associated with a poor prognosis. Neurosurgical removal of intracerebral hematoma has limited benefit and no pharmacotherapies are available. In acute ICH, primary tissue damage is followed by secondary pathology, where the cellular and neuroinflammatory changes are poorly understood. METHODS We studied histological changes in postmortem tissue from a cohort of spontaneous supra-tentorial primary ICH cases (n = 27) with survival of 1-12 days, compared to a matched control group (n = 16) examined in corresponding regions. Hematoxylin-eosin and microglial (Iba1) immunolabelled sections were assessed at 0-2, 3-5, and 7-12 days post-ICH. RESULTS Peri-hematoma, the observed ICH-related changes include edema, tissue neutrophils and macrophages from day 1. Ischemic neurons and swollen endothelial cells were common at day 1 and universal after day 5, as were intramural erythrocytes within small vessel walls. Activated microglia were evident at day 1 post-ICH. There was a significant increase in Iba1 positive area fraction at 0-2 (threefold), 3-5 (fourfold), and 7-12 days post ICH (ninefold) relative to controls. Giant microglia were detected peri-hematoma from day 5 and consistently 7-12 days post-ICH. INTERPRETATION Our data indicate that neuroinflammatory processes commence from day 1 post-ICH with changing microglial size and morphology following ICH and up to day 12. From day 5 some microglia exhibit a novel multiply nucleated morphology, which may be related to changing phagocytic function. Understanding the time course of neuroinflammatory changes, post-ICH may reveal novel targets for therapy and brain restoration.
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Affiliation(s)
- Anan Shtaya
- Neuroscience Research Centre, Molecular and Clinical Sciences Research InstituteSt. George’s, University of LondonLondonUK
| | - Leslie R. Bridges
- Department of Cellular PathologySt George's University Hospitals NHS Foundation TrustLondonUK
| | - Margaret M. Esiri
- Nuffield Department of Clinical NeurosciencesOxford UniversityOxfordUK
| | - Joanne Lam‐Wong
- Department of Cellular PathologySt George's University Hospitals NHS Foundation TrustLondonUK
| | - James A. R. Nicoll
- Clinical Neurosciences, Clinical & Experimental SciencesUniversity of SouthamptonSouthamptonUK
| | - Delphine Boche
- Clinical Neurosciences, Clinical & Experimental SciencesUniversity of SouthamptonSouthamptonUK
| | - Atticus H. Hainsworth
- Neuroscience Research Centre, Molecular and Clinical Sciences Research InstituteSt. George’s, University of LondonLondonUK
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22
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Raas Q, Gondcaille C, Hamon Y, Leoni V, Caccia C, Ménétrier F, Lizard G, Trompier D, Savary S. CRISPR/Cas9-mediated knockout of Abcd1 and Abcd2 genes in BV-2 cells: novel microglial models for X-linked Adrenoleukodystrophy. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:704-714. [DOI: 10.1016/j.bbalip.2019.02.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 01/24/2019] [Accepted: 02/09/2019] [Indexed: 01/08/2023]
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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: 57] [Impact Index Per Article: 9.5] [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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Rajapakse D, Chen M, Curtis TM, Xu H. PKCζ-dependent upregulation of p27kip1 contributes to oxidative stress induced retinal pigment epithelial cell multinucleation. Aging (Albany NY) 2018; 9:2052-2068. [PMID: 29016360 PMCID: PMC5680555 DOI: 10.18632/aging.101299] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/28/2017] [Indexed: 01/24/2023]
Abstract
Retinal pigment epithelial (RPE) cells increase in size and multinucleate during aging. We have shown using human and mouse cell lines that oxidised photoreceptor outer segments (oxPOS)-induced cytokinesis failure is related to RPE cell multinucleation, although the underlying mechanism remains unknown. This study investigated the role of the PKC pathway in oxPOS-induced RPE multinucleation using ARPE19 cells. oxPOS treatment promoted PKC activity and upregulated the mRNA expression of PKC α, δ, ζ, ι and μ. Inhibition of PKCα with Gö6976 resulted in a 33% reduction of multinucleate ARPE19 cells, whereas inhibition of PKCζ with Gö6983 led to a 50% reduction in multinucleate ARPE19 cells. Furthermore, oxPOS treatment induced a PKCζ-dependent upregulation of the Cdk inhibitor p27kip1, its inhibition using A2CE reduced oxPOS-induced ARPE19 multinucleation. Our results suggest that oxPOS-induced ARPE19 cytokinesis failure is, at least in part, due to the upregulation of p27kip1 through activating the PKC, particularly PKCζ pathway. Targeting the PKCζ-p27kip1 signalling axis may be a novel approach to restore RPE repair capacity during aging.
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Affiliation(s)
- Dinusha Rajapakse
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, BT97 BL, UK
| | - Mei Chen
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, BT97 BL, UK
| | - Tim M Curtis
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, BT97 BL, UK
| | - Heping Xu
- Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, BT97 BL, UK
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Epothilone D inhibits microglia-mediated spread of alpha-synuclein aggregates. Mol Cell Neurosci 2018; 89:80-94. [PMID: 29673913 DOI: 10.1016/j.mcn.2018.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/19/2018] [Accepted: 04/13/2018] [Indexed: 11/21/2022] Open
Abstract
Multiple System Atrophy (MSA) is a progressive neurodegenerative disease characterized by chronic neuroinflammation and widespread α-synuclein (α-syn) cytoplasmic inclusions. Neuroinflammation associated with microglial cells is typically located in brain regions with α-syn deposits. The potential link between microglial cell migration and the transport of pathological α-syn protein in MSA was investigated. Qualitative analysis via immunofluorescence of MSA cases (n = 4) revealed microglial cells bearing α-syn inclusions distal from oligodendrocytes bearing α-syn cytoplasmic inclusions, as well as close interactions between microglia and oligodendrocytes bearing α-syn, suggestive of a potential transfer mechanism between microglia and α-syn bearing cells in MSA and the possibility of microglia acting as a mobile vehicle to spread α-syn between anatomically connected brain regions. Further In vitro experiments using microglial-like differentiated THP-1 cells were conducted to investigate if microglial cells could act as potential transporters of α-syn. Monomeric or aggregated α-syn was immobilized at the centre of glass coverslips and treated with either cell free medium, undifferentiated THP-1 cells or microglial-like phorbol-12-myristate-13-acetate differentiated THP-1 cells (48 h; n = 3). A significant difference in residual immobilized α-syn density was observed between cell free controls and differentiated (p = 0.016) as well as undifferentiated and differentiated THP-1 cells (p = 0.032) when analysed by quantitative immunofluorescence. Furthermore, a significantly greater proportion of differentiated cells were observed bearing α-syn aggregates distal from the immobilized protein than their non-differentiated counterparts (p = 0.025). Similar results were observed with Highly Aggressive Proliferating Immortalised (HAPI) microglial cells, with cells exposed to aggregated α-syn yielding lower residual immobilized α-syn (p = 0.004) and a higher proportion of α-syn positive distal cells (p = 0.001) than cells exposed to monomeric α-syn. Co-treatment of THP-1 groups with the tubulin depolymerisation inhibitor, Epothilone D (EpoD; 10 nM), was conducted to investigate if inhibition of microtubule activity had an effect on cell migration and residual immobilized α-syn density. There was a significant increase in both residual immobilized α-syn between EpoD treated and non-treated differentiated cells exposed to monomeric (p = 0.037) and aggregated (p = 0.018) α-syn, but not with undifferentiated cells. Differentiated THP-1 cells exposed to immobilized aggregated α-syn showed a significant difference in the proportion of distal aggregate bearing cells between EpoD treated and untreated (p = 0.027). The results suggest microglia could play a role in α-syn transport in MSA, a role which could potentially be inhibited therapeutically by EpoD.
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Mishra PS, Vijayalakshmi K, Nalini A, Sathyaprabha TN, Kramer BW, Alladi PA, Raju TR. Etiogenic factors present in the cerebrospinal fluid from amyotrophic lateral sclerosis patients induce predominantly pro-inflammatory responses in microglia. J Neuroinflammation 2017; 14:251. [PMID: 29246232 PMCID: PMC5732516 DOI: 10.1186/s12974-017-1028-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 12/08/2017] [Indexed: 11/18/2022] Open
Abstract
Background Microglial cell-associated neuroinflammation is considered as a potential contributor to the pathophysiology of sporadic amyotrophic lateral sclerosis. However, the specific role of microglia in the disease pathogenesis remains to be elucidated. Methods We studied the activation profiles of the microglial cultures exposed to the cerebrospinal fluid from these patients which recapitulates the neurodegeneration seen in sporadic amyotrophic lateral sclerosis. This was done by investigating the morphological and functional changes including the expression levels of prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), TNF-α, IL-6, IFN-γ, IL-10, inducible nitric oxide synthase (iNOS), arginase, and trophic factors. We also studied the effect of chitotriosidase, the inflammatory protein found upregulated in the cerebrospinal fluid from amyotrophic lateral sclerosis patients, on these cultures. Results We report that the cerebrospinal fluid from amyotrophic lateral sclerosis patients could induce an early and potent response in the form of microglial activation, skewed primarily towards a pro-inflammatory profile. It was seen in the form of upregulation of the pro-inflammatory cytokines and factors including IL-6, TNF-α, iNOS, COX-2, and PGE2. Concomitantly, a downregulation of beneficial trophic factors and anti-inflammatory markers including VEGF, glial cell line-derived neurotrophic factor, and IFN-γ was seen. In addition, chitotriosidase-1 appeared to act specifically via the microglial cells. Conclusion Our findings demonstrate that the cerebrospinal fluid from amyotrophic lateral sclerosis patients holds enough cues to induce microglial inflammatory processes as an early event, which may contribute to the neurodegeneration seen in the sporadic amyotrophic lateral sclerosis. These findings highlight the dynamic role of microglial cells in the pathogenesis of the disease, thus suggesting the need for a multidimensional and temporally guarded therapeutic approach targeting the inflammatory pathways for its treatment. Electronic supplementary material The online version of this article (10.1186/s12974-017-1028-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Pooja-Shree Mishra
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India.,Present Address: Centre de Recherche CERVO, Quebec, QC, G1J 2G3, Canada
| | - K Vijayalakshmi
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India
| | - A Nalini
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India
| | - T N Sathyaprabha
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India
| | - B W Kramer
- School of Mental Health and Neuroscience, Maastricht Universitair Medisch Centrum, Maastricht, Limburg, Netherlands
| | - Phalguni Anand Alladi
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India
| | - T R Raju
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India.
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Horn V, Triantafyllopoulou A. DNA damage signaling and polyploid macrophages in chronic inflammation. Curr Opin Immunol 2017; 50:55-63. [PMID: 29202328 DOI: 10.1016/j.coi.2017.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 10/30/2017] [Accepted: 11/17/2017] [Indexed: 01/01/2023]
Abstract
Whole genome duplications, an important step in cancer development, also occur in the macrophage lineage in disease: large multinucleated macrophages found within compact, ordered aggregates of immune cells, called granulomas, are a well-known histologic entity. Very recent work suggests that granuloma macrophages remarkably acquire epithelial cell features and the genotoxic stress response instructs granuloma macrophage genome duplications, suggesting that granuloma macrophages and pre-malignant epithelial cells may share common mechanisms of adaptation to chronic genotoxic stress. Exploring these mechanisms is key for a better understanding of the pathogenesis of chronic inflammatory diseases. Here we review the mechanisms of macrophage polyploidization, the role of DNA damage signaling in this process and the function of polyploid macrophages, with a focus on chronic inflammation.
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Affiliation(s)
- Veronika Horn
- Department of Rheumatology and Clinical Immunology, Charité University Medical Center, D-10117 Berlin, Germany; Department of Rheumatology and Clinical Immunology, University Medical Center Freiburg, D-79106 Freiburg, Germany
| | - Antigoni Triantafyllopoulou
- Department of Rheumatology and Clinical Immunology, Charité University Medical Center, D-10117 Berlin, Germany; Department of Rheumatology and Clinical Immunology, University Medical Center Freiburg, D-79106 Freiburg, Germany; German Rheumatism Research Center, A Leibniz Institute, D-10117 Berlin, Germany; Institute of Microbiology, Charité University Medical Center, D-12203 Berlin, Germany.
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28
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Nicaise AM, Bongarzone ER, Crocker SJ. A microglial hypothesis of globoid cell leukodystrophy pathology. J Neurosci Res 2017; 94:1049-61. [PMID: 27638591 DOI: 10.1002/jnr.23773] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/05/2016] [Accepted: 05/06/2016] [Indexed: 11/09/2022]
Abstract
Globoid cell leukodystrophy (GLD), also known as Krabbe's disease, is a fatal demyelinating disease accompanied by the formation of giant, multinucleated cells called globoid cells. Previously believed to be a byproduct of inflammation, these cells can be found early in disease before evidence of any damage. The precise mechanism by which these globoid cells cause oligodendrocyte dysfunction is not completely understood, nor is their cell type defined. This Review outlines the idea that microglial cells are transformed into an unknown and undefined novel M3 phenotype in GLD, which is cytotoxic to oligodendrocytes, leading to disease progression. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Alexandra M Nicaise
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut
| | - Ernesto R Bongarzone
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois
| | - Stephen J Crocker
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, Connecticut.
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Castellano P, Prevedel L, Eugenin EA. HIV-infected macrophages and microglia that survive acute infection become viral reservoirs by a mechanism involving Bim. Sci Rep 2017; 7:12866. [PMID: 28993666 PMCID: PMC5634422 DOI: 10.1038/s41598-017-12758-w] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 09/15/2017] [Indexed: 12/17/2022] Open
Abstract
While HIV kills most of the cells it infects, a small number of infected cells survive and become latent viral reservoirs, posing a significant barrier to HIV eradication. However, the mechanism by which immune cells resist HIV-induced apoptosis is still incompletely understood. Here, we demonstrate that while acute HIV infection of human microglia/macrophages results in massive apoptosis, a small population of HIV-infected cells survive infection, silence viral replication, and can reactivate viral production upon specific treatments. We also found that HIV fusion inhibitors intended for use as antiretroviral therapies extended the survival of HIV-infected macrophages. Analysis of the pro- and anti-apoptotic pathways indicated no significant changes in Bcl-2, Mcl-1, Bak, Bax or caspase activation, suggesting that HIV blocks a very early step of apoptosis. Interestingly, Bim, a highly pro-apoptotic negative regulator of Bcl-2, was upregulated and recruited into the mitochondria in latently HIV-infected macrophages both in vitro and in vivo. Together, these results demonstrate that macrophages/microglia act as HIV reservoirs and utilize a novel mechanism to prevent HIV-induced apoptosis. Furthermore, they also suggest that Bim recruitment to mitochondria could be used as a biomarker of viral reservoirs in vivo.
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Affiliation(s)
- Paul Castellano
- Public Health Research Institute (PHRI), Newark, NJ, USA
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Rutgers the State University of NJ, Newark, NJ, USA
| | - Lisa Prevedel
- Public Health Research Institute (PHRI), Newark, NJ, USA
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Rutgers the State University of NJ, Newark, NJ, USA
| | - Eliseo A Eugenin
- Public Health Research Institute (PHRI), Newark, NJ, USA.
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Rutgers the State University of NJ, Newark, NJ, USA.
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Heinrich F, Lehmbecker A, Raddatz BB, Kegler K, Tipold A, Stein VM, Kalkuhl A, Deschl U, Baumgärtner W, Ulrich R, Spitzbarth I. Morphologic, phenotypic, and transcriptomic characterization of classically and alternatively activated canine blood-derived macrophages in vitro. PLoS One 2017; 12:e0183572. [PMID: 28817687 PMCID: PMC5560737 DOI: 10.1371/journal.pone.0183572] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 08/07/2017] [Indexed: 12/12/2022] Open
Abstract
Macrophages are a heterogeneous cell population playing a pivotal role in tissue homeostasis and inflammation, and their phenotype strongly depends on the micromilieu. Despite its increasing importance as a translational animal model for human diseases, there is a considerable gap of knowledge with respect to macrophage polarization in dogs. The present study comprehensively investigated the morphologic, phenotypic, and transcriptomic characteristics of unstimulated (M0), M1- (GM-CSF, LPS, IFNγ-stimulated) and M2- (M-CSF, IL-4-stimulated)-polarized canine blood-derived macrophages in vitro. Scanning electron microscopy revealed distinct morphologies of polarized macrophages with formation of multinucleated cells in M2-macrophages, while immunofluorescence employing literature-based prototype-antibodies against CD16, CD32, iNOS, MHC class II (M1-markers), CD163, CD206, and arginase-1 (M2-markers) demonstrated that only CD206 was able to discriminate M2-macrophages from both other phenotypes, highlighting this molecule as a promising marker for canine M2-macrophages. Global microarray analysis revealed profound changes in the transcriptome of polarized canine macrophages. Functional analysis pointed out that M1-polarization was associated with biological processes such as "respiratory burst", whereas M2-polarization was associated with processes such as "mitosis". Literature-based marker gene selection revealed only minor overlaps in the gene sets of the dog compared to prototype markers of murine and human macrophages. Biomarker selection using supervised clustering suggested latexin (LXN) and membrane-spanning 4-domains, subfamily A, member 2 (MS4A2) to be the most powerful predicting biomarkers for canine M1- and M2-macrophages, respectively. Immunofluorescence for both markers demonstrated expression of both proteins by macrophages in vitro but failed to reveal differences between canine M1 and M2-macrophages. The present study provides a solid basis for future studies upon the role of macrophage polarization in spontaneous diseases of the dog, a species that has emerging importance for translational research.
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Affiliation(s)
- Franziska Heinrich
- Department of Pathology, University of Veterinary Medicine Hannover Foundation, Bünteweg 17, Hannover, Germany
- Center for Systems Neuroscience, Bünteweg 2, Hannover, Germany
| | - Annika Lehmbecker
- Department of Pathology, University of Veterinary Medicine Hannover Foundation, Bünteweg 17, Hannover, Germany
- Center for Systems Neuroscience, Bünteweg 2, Hannover, Germany
| | - Barbara B. Raddatz
- Department of Pathology, University of Veterinary Medicine Hannover Foundation, Bünteweg 17, Hannover, Germany
- Center for Systems Neuroscience, Bünteweg 2, Hannover, Germany
| | - Kristel Kegler
- Department of Pathology, University of Veterinary Medicine Hannover Foundation, Bünteweg 17, Hannover, Germany
- Center for Systems Neuroscience, Bünteweg 2, Hannover, Germany
| | - Andrea Tipold
- Center for Systems Neuroscience, Bünteweg 2, Hannover, Germany
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover Foundation, Bünteweg 2, Hannover, Germany
| | - Veronika M. Stein
- Center for Systems Neuroscience, Bünteweg 2, Hannover, Germany
- Department of Clinical Veterinary Sciences, Vetsuisse Faculty, University of Bern, Laenggassstrasse 128, Bern, Switzerland
| | - Arno Kalkuhl
- Boehringer Ingelheim Pharma GmbH & Co.KG, Department of Non-clinical Drug Safety, Birkendorfer Str. 65, Biberach, Germany
| | - Ulrich Deschl
- Boehringer Ingelheim Pharma GmbH & Co.KG, Department of Non-clinical Drug Safety, Birkendorfer Str. 65, Biberach, Germany
| | - Wolfgang Baumgärtner
- Department of Pathology, University of Veterinary Medicine Hannover Foundation, Bünteweg 17, Hannover, Germany
- Center for Systems Neuroscience, Bünteweg 2, Hannover, Germany
| | - Reiner Ulrich
- Department of Pathology, University of Veterinary Medicine Hannover Foundation, Bünteweg 17, Hannover, Germany
- Friedrich-Loeffler-Institute, Department of Experimental Animal Facilities and Biorisk Management, Südufer 10, Greifswald, Germany
| | - Ingo Spitzbarth
- Department of Pathology, University of Veterinary Medicine Hannover Foundation, Bünteweg 17, Hannover, Germany
- Center for Systems Neuroscience, Bünteweg 2, Hannover, Germany
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Cui FM, Sun XJ, Huang CC, Chen Q, He YM, Zhang SM, Guan H, Song M, Zhou PK, Hou J. Inhibition of c-Myc expression accounts for an increase in the number of multinucleated cells in human cervical epithelial cells. Oncol Lett 2017; 14:2878-2886. [PMID: 28928827 PMCID: PMC5588452 DOI: 10.3892/ol.2017.6554] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 03/23/2017] [Indexed: 01/06/2023] Open
Abstract
The present study aimed to explore the mechanisms by which c-Myc is involved in mitotic catastrophe. HeLa-630 is a cell line stably silenced for c-Myc expression that was established in the laboratory of the School of Radiation Medicine and Protection. Multinucleated cells were observed in this line, and gene expression analysis was utilized to examine differences in gene expression in these cells compared with in the control cells transfected with the control plasmid. Gene ontology analysis was performed for differentially expressed genes. Expression profile analyses revealed that cells with silenced c-Myc exhibited abnormal expression patterns of genes involved in various functions, including the regulation of microtubule nucleation, centrosome duplication, the formation of pericentriolar material, DNA synthesis and metabolism, protein metabolism and the regulation of ion concentrations. Pathway analyses of differentially expressed genes demonstrated that these genes were primarily involved in diverse signal transduction pathways, including not only the adherens junction pathway, the transforming growth factor-β signaling pathway and the Wnt signaling pathway, among others, but also signaling pathways with roles in cytokine and immune regulation. The proportion of multinucleated cells with multipolar spindles was significantly higher in silenced c-Myc cells as compared with the control cells, and this discrepancy became more pronounced following cell irradiation. The inhibition of c-Myc in tumors may account for the radiosensitization of certain tumor cell types.
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Affiliation(s)
- Feng Mei Cui
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China.,Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Xiu Jin Sun
- Department of Radiation Oncology, Jiangsu Cancer Hospital, Nanjing, Jiangsu 210000, P.R. China
| | - Cheng Cheng Huang
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Qiu Chen
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China.,Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Yong Ming He
- Department of Cardiology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Shi Meng Zhang
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, Beijing 100850, P.R. China
| | - Hua Guan
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, Beijing 100850, P.R. China
| | - Man Song
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Ping Kun Zhou
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China.,Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, Beijing 100850, P.R. China
| | - Jun Hou
- Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai 200032, P.R. China
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Nomura K, Vilalta A, Allendorf DH, Hornik TC, Brown GC. Activated Microglia Desialylate and Phagocytose Cells via Neuraminidase, Galectin-3, and Mer Tyrosine Kinase. THE JOURNAL OF IMMUNOLOGY 2017; 198:4792-4801. [PMID: 28500071 PMCID: PMC5458330 DOI: 10.4049/jimmunol.1502532] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 04/12/2017] [Indexed: 12/31/2022]
Abstract
Activated microglia can phagocytose dying, stressed, or excess neurons and synapses via the phagocytic receptor Mer tyrosine kinase (MerTK). Galectin-3 (Gal-3) can cross-link surface glycoproteins by binding galactose residues that are normally hidden below terminal sialic acid residues. Gal-3 was recently reported to opsonize cells via activating MerTK. We found that LPS-activated BV-2 microglia rapidly released Gal-3, which was blocked by calcineurin inhibitors. Gal-3 bound to MerTK on microglia and to stressed PC12 (neuron-like) cells, and it increased microglial phagocytosis of PC12 cells or primary neurons, which was blocked by inhibition of MerTK. LPS-activated microglia exhibited a sialidase activity that desialylated PC12 cells and could be inhibited by Tamiflu, a neuraminidase (sialidase) inhibitor. Sialidase treatment of PC12 cells enabled Gal-3 to bind and opsonize the live cells for phagocytosis by microglia. LPS-induced microglial phagocytosis of PC12 was prevented by small interfering RNA knockdown of Gal-3 in microglia, lactose inhibition of Gal-3 binding, inhibition of neuraminidase with Tamiflu, or inhibition of MerTK by UNC569. LPS-induced phagocytosis of primary neurons by primary microglia was also blocked by inhibition of MerTK. We conclude that activated microglia release Gal-3 and a neuraminidase that desialylates microglial and PC12 surfaces, enabling Gal-3 binding to PC12 cells and their phagocytosis via MerTK. Thus, Gal-3 acts as an opsonin of desialylated surfaces, and inflammatory loss of neurons or synapses may potentially be blocked by inhibiting neuraminidases, Gal-3, or MerTK.
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Affiliation(s)
- Koji Nomura
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Anna Vilalta
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - David H Allendorf
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Tamara C Hornik
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
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Neniskyte U, Fricker M, Brown GC. Amyloid β induces microglia to phagocytose neurons via activation of protein kinase Cs and NADPH oxidase. Int J Biochem Cell Biol 2016; 81:346-355. [DOI: 10.1016/j.biocel.2016.06.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/25/2016] [Accepted: 06/03/2016] [Indexed: 10/21/2022]
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Ramírez G, Ressel L, Altimira J, Vilafranca M. Cutaneous Heterotopic Brain Tissue (Neuroglial Choristoma) with Dysplastic Features in a Kitten. J Comp Pathol 2016; 155:50-4. [DOI: 10.1016/j.jcpa.2016.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/30/2016] [Accepted: 05/07/2016] [Indexed: 10/21/2022]
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Chen M, Rajapakse D, Fraczek M, Luo C, Forrester JV, Xu H. Retinal pigment epithelial cell multinucleation in the aging eye - a mechanism to repair damage and maintain homoeostasis. Aging Cell 2016; 15:436-45. [PMID: 26875723 PMCID: PMC4854907 DOI: 10.1111/acel.12447] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2015] [Indexed: 11/29/2022] Open
Abstract
Retinal pigment epithelial (RPE) cells are central to retinal health and homoeostasis. Dysfunction or death of RPE cells underlies many age-related retinal degenerative disorders particularly age-related macular degeneration. During aging RPE cells decline in number, suggesting an age-dependent cell loss. RPE cells are considered to be postmitotic, and how they repair damage during aging remains poorly defined. We show that RPE cells increase in size and become multinucleate during aging in C57BL/6J mice. Multinucleation appeared not to be due to cell fusion, but to incomplete cell division, that is failure of cytokinesis. Interestingly, the phagocytic activity of multinucleate RPE cells was not different from that of mononuclear RPE cells. Furthermore, exposure of RPE cells in vitro to photoreceptor outer segment (POS), particularly oxidized POS, dose-dependently promoted multinucleation and suppressed cell proliferation. Both failure of cytokinesis and suppression of proliferation required contact with POS. Exposure to POS also induced reactive oxygen species and DNA oxidation in RPE cells. We propose that RPE cells have the potential to proliferate in vivo and to repair defects in the monolayer. We further propose that the conventionally accepted 'postmitotic' status of RPE cells is due to a modified form of contact inhibition mediated by POS and that RPE cells are released from this state when contact with POS is lost. This is seen in long-standing rhegmatogenous retinal detachment as overtly proliferating RPE cells (proliferative vitreoretinopathy) and more subtly as multinucleation during normal aging. Age-related oxidative stress may promote failure of cytokinesis and multinucleation in RPE cells.
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Affiliation(s)
- Mei Chen
- Centre for Experimental Medicine; School of Medicine, Dentistry & Biomedical Sciences; Queen's University Belfast; 97 Lisburn Road Belfast BT9 7 BL UK
| | - Dinusha Rajapakse
- Centre for Experimental Medicine; School of Medicine, Dentistry & Biomedical Sciences; Queen's University Belfast; 97 Lisburn Road Belfast BT9 7 BL UK
| | - Monika Fraczek
- Section of Immunology and Infection; Division of Applied Medicine; School of Medicine and Dentistry; Institute of Medical Science; University of Aberdeen; Foresterhill Aberdeen AB25 2ZD UK
| | - Chang Luo
- Centre for Experimental Medicine; School of Medicine, Dentistry & Biomedical Sciences; Queen's University Belfast; 97 Lisburn Road Belfast BT9 7 BL UK
| | - John V. Forrester
- Section of Immunology and Infection; Division of Applied Medicine; School of Medicine and Dentistry; Institute of Medical Science; University of Aberdeen; Foresterhill Aberdeen AB25 2ZD UK
- Ocular Immunology Program; Centre for Ophthalmology and Visual Science; The University of Western Australia; Perth WA 6009 Australia
- Centre for Experimental Immunology; Lions Eye Institute; Nedlands WA 6009 Australia
| | - Heping Xu
- Centre for Experimental Medicine; School of Medicine, Dentistry & Biomedical Sciences; Queen's University Belfast; 97 Lisburn Road Belfast BT9 7 BL UK
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Abiega O, Beccari S, Diaz-Aparicio I, Nadjar A, Layé S, Leyrolle Q, Gómez-Nicola D, Domercq M, Pérez-Samartín A, Sánchez-Zafra V, Paris I, Valero J, Savage JC, Hui CW, Tremblay MÈ, Deudero JJP, Brewster AL, Anderson AE, Zaldumbide L, Galbarriatu L, Marinas A, Vivanco MDM, Matute C, Maletic-Savatic M, Encinas JM, Sierra A. Neuronal Hyperactivity Disturbs ATP Microgradients, Impairs Microglial Motility, and Reduces Phagocytic Receptor Expression Triggering Apoptosis/Microglial Phagocytosis Uncoupling. PLoS Biol 2016; 14:e1002466. [PMID: 27228556 PMCID: PMC4881984 DOI: 10.1371/journal.pbio.1002466] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 04/21/2016] [Indexed: 12/24/2022] Open
Abstract
Phagocytosis is essential to maintain tissue homeostasis in a large number of inflammatory and autoimmune diseases, but its role in the diseased brain is poorly explored. Recent findings suggest that in the adult hippocampal neurogenic niche, where the excess of newborn cells undergo apoptosis in physiological conditions, phagocytosis is efficiently executed by surveillant, ramified microglia. To test whether microglia are efficient phagocytes in the diseased brain as well, we confronted them with a series of apoptotic challenges and discovered a generalized response. When challenged with excitotoxicity in vitro (via the glutamate agonist NMDA) or inflammation in vivo (via systemic administration of bacterial lipopolysaccharides or by omega 3 fatty acid deficient diets), microglia resorted to different strategies to boost their phagocytic efficiency and compensate for the increased number of apoptotic cells, thus maintaining phagocytosis and apoptosis tightly coupled. Unexpectedly, this coupling was chronically lost in a mouse model of mesial temporal lobe epilepsy (MTLE) as well as in hippocampal tissue resected from individuals with MTLE, a major neurological disorder characterized by seizures, excitotoxicity, and inflammation. Importantly, the loss of phagocytosis/apoptosis coupling correlated with the expression of microglial proinflammatory, epileptogenic cytokines, suggesting its contribution to the pathophysiology of epilepsy. The phagocytic blockade resulted from reduced microglial surveillance and apoptotic cell recognition receptor expression and was not directly mediated by signaling through microglial glutamate receptors. Instead, it was related to the disruption of local ATP microgradients caused by the hyperactivity of the hippocampal network, at least in the acute phase of epilepsy. Finally, the uncoupling led to an accumulation of apoptotic newborn cells in the neurogenic niche that was due not to decreased survival but to delayed cell clearance after seizures. These results demonstrate that the efficiency of microglial phagocytosis critically affects the dynamics of apoptosis and urge to routinely assess the microglial phagocytic efficiency in neurodegenerative disorders. Phagocytosis by microglia is tightly coupled to apoptosis, swiftly removing apoptotic cells and actively maintaining tissue homeostasis, but the neuronal hyperactivity associated with epilepsy disrupts the ATP gradients that drive phagocytosis, leading to the accumulation of apoptotic cells and inflammation. Phagocytosis, the engulfment and digestion of cellular debris, is at the core of the regenerative response of the damaged tissue, because it prevents the spillover of toxic intracellular contents and is actively anti-inflammatory. In the brain, the professional phagocytes are microglia, whose dynamic processes rapidly engulf and degrade cells undergoing apoptosis—programmed cell death—in physiological conditions. Thus, microglia hold the key to brain regeneration, but their efficiency as phagocytes in the diseased brain is only presumed. Here, we have discovered a generalized response of microglia to apoptotic challenge induced by excitotoxicity and inflammation, in which they boost their phagocytic efficiency to account for the increase in apoptosis. To our surprise, this apoptosis/microglial phagocytosis coupling was lost in the hippocampus from human and experimental mesial temporal lobe epilepsy (MTLE), a major neurodegenerative disorder characterized by excitotoxicity, inflammation, and seizures. This uncoupling was due to widespread ATP release during neuronal hyperactivity, which “blinded” microglia to the ATP microgradients released by apoptotic cells as “find-me” signals. The impairment of phagocytosis led to the accumulation of apoptotic cells and the build-up of a detrimental inflammatory reaction. Our data advocates for systematic assessment of the efficiency of microglial phagocytosis in brain disorders.
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Affiliation(s)
- Oihane Abiega
- Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain
- University of the Basque Country, Leioa, Spain
| | - Sol Beccari
- Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain
- University of the Basque Country, Leioa, Spain
| | - Irune Diaz-Aparicio
- Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain
- University of the Basque Country, Leioa, Spain
| | | | - Sophie Layé
- Université Bordeaux Segalen, Bordeaux, France
| | | | - Diego Gómez-Nicola
- Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - María Domercq
- Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain
- University of the Basque Country, Leioa, Spain
| | - Alberto Pérez-Samartín
- Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain
- University of the Basque Country, Leioa, Spain
| | - Víctor Sánchez-Zafra
- Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain
- University of the Basque Country, Leioa, Spain
| | - Iñaki Paris
- Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain
- University of the Basque Country, Leioa, Spain
| | - Jorge Valero
- Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain
- University of the Basque Country, Leioa, Spain
- Ikerbasque Foundation, Bilbao, Spain
| | - Julie C. Savage
- Centre de recherche du CHU de Québec, Axe Neurosciences, Québec, Canada
- Université Laval, Département de médecine moléculaire, Québec, Canada
| | - Chin-Wai Hui
- Centre de recherche du CHU de Québec, Axe Neurosciences, Québec, Canada
- Université Laval, Département de médecine moléculaire, Québec, Canada
| | - Marie-Ève Tremblay
- Centre de recherche du CHU de Québec, Axe Neurosciences, Québec, Canada
- Université Laval, Département de médecine moléculaire, Québec, Canada
| | - Juan J. P. Deudero
- Baylor College of Medicine, The Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, United States of America
| | - Amy L. Brewster
- Baylor College of Medicine, The Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, United States of America
| | - Anne E. Anderson
- Baylor College of Medicine, The Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, United States of America
| | | | | | | | | | - Carlos Matute
- Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain
- University of the Basque Country, Leioa, Spain
| | | | - Juan M. Encinas
- Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain
- University of the Basque Country, Leioa, Spain
- Baylor College of Medicine, The Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, United States of America
| | - Amanda Sierra
- Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, Zamudio, Spain
- University of the Basque Country, Leioa, Spain
- Baylor College of Medicine, The Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, United States of America
- * E-mail:
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Hornik TC, Vilalta A, Brown GC. Activated microglia cause reversible apoptosis of pheochromocytoma cells, inducing their cell death by phagocytosis. J Cell Sci 2015; 129:65-79. [PMID: 26567213 DOI: 10.1242/jcs.174631] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 11/10/2015] [Indexed: 12/15/2022] Open
Abstract
Some apoptotic processes, such as phosphatidylserine exposure, are potentially reversible and do not necessarily lead to cell death. However, phosphatidylserine exposure can induce phagocytosis of a cell, resulting in cell death by phagocytosis: phagoptosis. Phagoptosis of neurons by microglia might contribute to neuropathology, whereas phagoptosis of tumour cells by macrophages might limit cancer. Here, we examined the mechanisms by which BV-2 microglia killed co-cultured pheochromocytoma (PC12) cells that were either undifferentiated or differentiated into neuronal cells. We found that microglia activated by lipopolysaccharide rapidly phagocytosed PC12 cells. Activated microglia caused reversible phosphatidylserine exposure on and reversible caspase activation in PC12 cells, and caspase inhibition prevented phosphatidylserine exposur and decreased subsequent phagocytosis. Nitric oxide was necessary and sufficient to induce the reversible phosphatidylserine exposure and phagocytosis. The PC12 cells were not dead at the time they were phagocytised, and inhibition of their phagocytosis left viable cells. Cell loss was inhibited by blocking phagocytosis mediated by phosphatidylserine, MFG-E8, vitronectin receptors or P2Y6 receptors. Thus, activated microglia can induce reversible apoptosis of target cells, which is insufficient to cause apoptotic cell death, but sufficient to induce their phagocytosis and therefore cell death by phagoptosis.
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Affiliation(s)
- Tamara C Hornik
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Anna Vilalta
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
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38
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Brown GC, Vilalta A. How microglia kill neurons. Brain Res 2015; 1628:288-297. [PMID: 26341532 DOI: 10.1016/j.brainres.2015.08.031] [Citation(s) in RCA: 205] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 08/03/2015] [Accepted: 08/24/2015] [Indexed: 12/11/2022]
Abstract
Microglia are resident brain macrophages that become inflammatory activated in most brain pathologies. Microglia normally protect neurons, but may accidentally kill neurons when attempting to limit infections or damage, and this may be more common with degenerative disease as there was no significant selection pressure on the aged brain in the past. A number of mechanisms by which activated microglia kill neurons have been identified, including: (i) stimulation of the phagocyte NADPH oxidase (PHOX) to produce superoxide and derivative oxidants, (ii) expression of inducible nitric oxide synthase (iNOS) producing NO and derivative oxidants, (iii) release of glutamate and glutaminase, (iv) release of TNFα, (v) release of cathepsin B, (vi) phagocytosis of stressed neurons, and (vii) decreased release of nutritive BDNF and IGF-1. PHOX stimulation contributes to microglial activation, but is not directly neurotoxic unless NO is present. NO is normally neuroprotective, but can react with superoxide to produce neurotoxic peroxynitrite, or in the presence of hypoxia inhibit mitochondrial respiration. Glutamate can be released by glia or neurons, but is neurotoxic only if the neurons are depolarised, for example as a result of mitochondrial inhibition. TNFα is normally neuroprotective, but can become toxic if caspase-8 or NF-κB activation are inhibited. If the above mechanisms do not kill neurons, they may still stress the neurons sufficiently to make them susceptible to phagocytosis by activated microglia. We review here whether microglial killing of neurons is an artefact, makes evolutionary sense or contributes in common neuropathologies and by what mechanisms. This article is part of a Special Issue entitled SI: Neuroprotection.
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Affiliation(s)
- Guy C Brown
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
| | - Anna Vilalta
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
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Pires LR, Rocha DN, Ambrosio L, Pêgo AP. The role of the surface on microglia function: implications for central nervous system tissue engineering. J R Soc Interface 2015; 12:rsif.2014.1224. [PMID: 25540243 DOI: 10.1098/rsif.2014.1224] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In tissue engineering, it is well accepted that a scaffold surface has a decisive impact on cell behaviour. Here we focused on microglia-the resident immune cells of the central nervous system (CNS)-and on their response to poly(trimethylene carbonate-co-ε-caprolactone) (P(TMC-CL)) fibrous and flat surfaces obtained by electrospinning and solvent cast, respectively. This study aims to provide cues for the design of instructive surfaces that can contribute to the challenging process of CNS regeneration. Cell morphology was evidently affected by the substrate, mirroring the surface main features. Cells cultured on flat substrates presented a round shape, while cells with elongated processes were observed on the electrospun fibres. A higher concentration of the pro-inflammatory cytokine tumour necrosis factor-α was detected in culture media from microglia on fibres. Still, astrogliosis is not exacerbated when astrocytes are cultured in the presence of microglia-conditioned media obtained from cultures in contact with either substrate. Furthermore, a significant percentage of microglia was found to participate in the process of myelin phagocytosis, with the formation of multinucleated giant cells being observed only on films. Altogether, the results presented suggest that microglia in contact with the tested substrates may contribute to the regeneration process, putting forward P(TMC-CL) substrates as supporting matrices for nerve regeneration.
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Affiliation(s)
- Liliana R Pires
- INEB-Instituto de Engenharia Biomédica, Porto, Portugal Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
| | - Daniela N Rocha
- INEB-Instituto de Engenharia Biomédica, Porto, Portugal Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
| | - Luigi Ambrosio
- Department of Chemical Sciences and Materials Technology, National Research Council of Italy, Rome, Italy
| | - Ana Paula Pêgo
- INEB-Instituto de Engenharia Biomédica, Porto, Portugal Faculdade de Engenharia, Universidade do Porto, Porto, Portugal Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
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Meulendyke KA, Croteau JD, Zink MC. HIV life cycle, innate immunity and autophagy in the central nervous system. Curr Opin HIV AIDS 2014; 9:565-71. [PMID: 25203639 PMCID: PMC4212891 DOI: 10.1097/coh.0000000000000106] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW In this era of modern combination antiretroviral therapy (cART) HIV-associated neurocognitive disorders (HAND) continue to affect a large portion of the infected population. In this review, we highlight recent discoveries that help to define the interplay between HIV life cycle, the innate immune system and cellular autophagy in the context of the central nervous system (CNS). RECENT FINDINGS Investigators have recently elucidated themes in HAND, which place it in a unique framework. Cells of macrophage lineage and probably astrocytes play a role in disseminating virus through the CNS. Each of these cell types responds to a diverse population of constantly evolving virus existing in an inflammatory environment. This occurs though the failure of both host antiviral mechanisms, such as autophagy, and innate immunological signalling pathways to control viral replication. SUMMARY The newest findings detailed in this review help define why HIV CNS disease is a difficult target for therapeutics and create hope that these new mechanisms may be exploited to attenuate viral replication and eliminate disease.
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Affiliation(s)
- Kelly A. Meulendyke
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Joshua D. Croteau
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - M. Christine Zink
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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Abstract
Microglia, the brain's professional phagocytes, can remove dead and dying neurons as well as synapses and the processes of live neurons. However, we and others have recently shown that microglia can also execute neuronal death by phagocytosing stressed-but-viable neurons - a process that we have termed phagoptosis. In this Progress article, we discuss evidence suggesting that phagoptosis may contribute to neuronal loss during brain development, inflammation, ischaemia and neurodegeneration.
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Lindberg OR, Brederlau A, Kuhn HG. Epidermal growth factor treatment of the adult brain subventricular zone leads to focal microglia/macrophage accumulation and angiogenesis. Stem Cell Reports 2014; 2:440-8. [PMID: 24749069 PMCID: PMC3986663 DOI: 10.1016/j.stemcr.2014.02.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 02/11/2014] [Accepted: 02/12/2014] [Indexed: 12/11/2022] Open
Abstract
One of the major components of the subventricular zone (SVZ) neurogenic niche is the specialized vasculature. The SVZ vasculature is thought to be important in regulating progenitor cell proliferation and migration. Epidermal growth factor (EGF) is a mitogen with a wide range of effects. When stem and progenitor cells in the rat SVZ are treated with EGF, using intracerebroventricular infusion, dysplastic polyps are formed. Upon extended infusion, blood vessels are recruited into the polyps. In the current study we demonstrate how polyps develop through distinct stages leading up to angiogenesis. As polyps progress, microglia/macrophages accumulate in the polyp core concurrent with increasing cell death. Both microglia/macrophage accumulation and cell death peak during angiogenesis and subsequently decline following polyp vascularization. This model of inducible angiogenesis in the SVZ neurogenic niche suggests involvement of microglia/macrophages in acquired angiogenesis and can be used in detail to study angiogenesis in the adult brain. EGF-induced growth of polyps leads to vessel recruitment and angiogenesis Four distinct stages are discernible in polyp development (I–IV) Microglia/macrophages and dying cells progressively accumulate in the polyp core Microglia/macrophages and dying cells are reduced after polyp vascularization
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Affiliation(s)
- Olle R Lindberg
- Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg 413 90, Sweden
| | - Anke Brederlau
- Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg 413 90, Sweden
| | - H Georg Kuhn
- Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg 413 90, Sweden
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