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Blaschke SJ, Rautenberg N, Endepols H, Jendro A, Konrad J, Vlachakis S, Wiedermann D, Schroeter M, Hoffmann B, Merkel R, Marklund N, Fink GR, Rueger MA. Early Blood-Brain Barrier Impairment as a Pathological Hallmark in a Novel Model of Closed-Head Concussive Brain Injury (CBI) in Mice. Int J Mol Sci 2024; 25:4837. [PMID: 38732053 PMCID: PMC11084321 DOI: 10.3390/ijms25094837] [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: 03/25/2024] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 05/13/2024] Open
Abstract
Concussion, caused by a rotational acceleration/deceleration injury mild enough to avoid structural brain damage, is insufficiently captured in recent preclinical models, hampering the relation of pathophysiological findings on the cellular level to functional and behavioral deficits. We here describe a novel model of unrestrained, single vs. repetitive concussive brain injury (CBI) in male C56Bl/6j mice. Longitudinal behavioral assessments were conducted for up to seven days afterward, alongside the evaluation of structural cerebral integrity by in vivo magnetic resonance imaging (MRI, 9.4 T), and validated ex vivo by histology. Blood-brain barrier (BBB) integrity was analyzed by means of fluorescent dextran- as well as immunoglobulin G (IgG) extravasation, and neuroinflammatory processes were characterized both in vivo by positron emission tomography (PET) using [18F]DPA-714 and ex vivo using immunohistochemistry. While a single CBI resulted in a defined, subacute neuropsychiatric phenotype, longitudinal cognitive testing revealed a marked decrease in spatial cognition, most pronounced in mice subjected to CBI at high frequency (every 48 h). Functional deficits were correlated to a parallel disruption of the BBB, (R2 = 0.29, p < 0.01), even detectable by a significant increase in hippocampal uptake of [18F]DPA-714, which was not due to activation of microglia, as confirmed immunohistochemically. Featuring a mild but widespread disruption of the BBB without evidence of macroscopic damage, this model induces a characteristic neuro-psychiatric phenotype that correlates to the degree of BBB disruption. Based on these findings, the BBB may function as both a biomarker of CBI severity and as a potential treatment target to improve recovery from concussion.
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Affiliation(s)
- Stefan J. Blaschke
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, 50923 Cologne, Germany; (N.R.); (A.J.); (M.S.); (G.R.F.); (M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, 52428 Juelich, Germany
| | - Nora Rautenberg
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, 50923 Cologne, Germany; (N.R.); (A.J.); (M.S.); (G.R.F.); (M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, 52428 Juelich, Germany
| | - Heike Endepols
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany;
- Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
- Nuclear Chemistry, Institute of Neuroscience and Medicine (INM-5), Research Centre Juelich, 52428 Juelich, Germany
| | - Aileen Jendro
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, 50923 Cologne, Germany; (N.R.); (A.J.); (M.S.); (G.R.F.); (M.A.R.)
| | - Jens Konrad
- Mechanobiology, Institute of Biological Information Processing (IBI-2), Research Centre Juelich, 52425 Juelich, Germany; (J.K.); (B.H.); (R.M.)
| | - Susan Vlachakis
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, 50923 Cologne, Germany; (N.R.); (A.J.); (M.S.); (G.R.F.); (M.A.R.)
| | - Dirk Wiedermann
- Multimodal Imaging Group, Max Planck Institute for Metabolism Research, 50931 Cologne, Germany;
| | - Michael Schroeter
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, 50923 Cologne, Germany; (N.R.); (A.J.); (M.S.); (G.R.F.); (M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, 52428 Juelich, Germany
| | - Bernd Hoffmann
- Mechanobiology, Institute of Biological Information Processing (IBI-2), Research Centre Juelich, 52425 Juelich, Germany; (J.K.); (B.H.); (R.M.)
| | - Rudolf Merkel
- Mechanobiology, Institute of Biological Information Processing (IBI-2), Research Centre Juelich, 52425 Juelich, Germany; (J.K.); (B.H.); (R.M.)
| | - Niklas Marklund
- Department of Clinical Sciences Lund, Neurosurgery, Lund University, 221 85 Lund, Sweden;
| | - Gereon R. Fink
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, 50923 Cologne, Germany; (N.R.); (A.J.); (M.S.); (G.R.F.); (M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, 52428 Juelich, Germany
| | - Maria A. Rueger
- Department of Neurology, Faculty of Medicine and University Hospital, University of Cologne, 50923 Cologne, Germany; (N.R.); (A.J.); (M.S.); (G.R.F.); (M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, 52428 Juelich, Germany
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Procès A, Alpizar YA, Halliez S, Brône B, Saudou F, Ris L, Gabriele S. Stretch-injury promotes microglia activation with enhanced phagocytic and synaptic stripping activities. Biomaterials 2024; 305:122426. [PMID: 38134473 DOI: 10.1016/j.biomaterials.2023.122426] [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: 05/14/2023] [Revised: 11/29/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023]
Abstract
Microglial cells, as the primary defense line in the central nervous system, play a crucial role in responding to various mechanical signals that can trigger their activation. Despite extensive research on the impact of chemical signaling on brain cells, the understanding of mechanical signaling in microglia remains limited. To bridge this gap, we subjected microglial cells to a singular mechanical stretch and compared their responses with those induced by lipopolysaccharide treatment, a well-established chemical activator. Here we show that stretching microglial cells leads to their activation, highlighting their significant mechanosensitivity. Stretched microglial cells exhibited distinct features, including elevated levels of Iba1 protein, a denser actin cytoskeleton, and increased persistence in migration. Unlike LPS-treated microglial cells, the secretory profile of chemokines and cytokines remained largely unchanged in response to stretching, except for TNF-α. Intriguingly, a single stretch injury resulted in more compacted chromatin and DNA damage, suggesting potential long-term genomic instabilities in stretched microglia. Using compartmentalized microfluidic chambers with neuronal networks, we observed that stretched microglial cells exhibited enhanced phagocytic and synaptic stripping activities. These findings collectively suggest that stretching events can unlock the immune potential of microglial cells, contributing to the maintenance of brain tissue homeostasis following mechanical injury.
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Affiliation(s)
- Anthony Procès
- Mechanobiology & Biomaterials Group, CIRMAP, Research Institute for Biosciences, University of Mons, B-7000, Mons, Belgium; Neuroscience Laboratory, Neuroscience Department, Research Institute for Biosciences, University of Mons, B-7000, Mons, Belgium
| | - Yeranddy A Alpizar
- Neurophysiology Laboratory, BIOMED Research Institute, UHasselt, B-3500, Hasselt, Belgium
| | - Sophie Halliez
- Univ. Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, F-59000, Lille, France
| | - Bert Brône
- Neurophysiology Laboratory, BIOMED Research Institute, UHasselt, B-3500, Hasselt, Belgium
| | - Frédéric Saudou
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neuroscience, F-38000, Grenoble, France
| | - Laurence Ris
- Neuroscience Laboratory, Neuroscience Department, Research Institute for Biosciences, University of Mons, B-7000, Mons, Belgium
| | - Sylvain Gabriele
- Mechanobiology & Biomaterials Group, CIRMAP, Research Institute for Biosciences, University of Mons, B-7000, Mons, Belgium.
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Shaughness MC, Pierron N, Smith AN, Byrnes KR. The Integrin Pathway Partially Mediates Stretch-Induced Deficits in Primary Rat Microglia. Mol Neurobiol 2023; 60:3396-3412. [PMID: 36856961 DOI: 10.1007/s12035-023-03291-1] [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: 04/25/2022] [Accepted: 02/21/2023] [Indexed: 03/02/2023]
Abstract
Stretch-injured microglia display significantly altered morphology, function and inflammatory-associated gene expression when cultured on a synthetic fibronectin substrate. However, the mechanism by which stretch induces these changes is unknown. Integrins, such as α5β1, mediate microglial attachment to fibronectin via the RGD binding peptide; following integrin ligation the integrin-associated signaling enzyme, focal adhesion kinase (FAK), autophosphorylates tyrosine residue 397 and mediates multiple downstream cellular processes. We therefore hypothesize that blocking the RGD binding/integrin pathway with a commercially available RGD peptide will mimic the stretch-induced morphological alterations and functional deficits in microglia. Further, we hypothesize that upregulation of stretch-inhibited downstream integrin signaling will reverse these effects. Using primary rat microglia, we tested the effects of RGD binding peptide and a FAK activator on cellular function and structure and response to stretch-injury. Similar to injured cells, RGD peptide administration significantly decreases media nitric oxide (NO) levels and iNOS expression and induced morphological alterations and migratory deficits. While stretch-injury and RGD peptide administration decreased phosphorylation of the tyrosine 397 residue on FAK, 20 nM of ZINC 40099027, an activator specific to the tyrosine 397 residue, rescued the stretch-induced decrease in FAK phosphorylation and ameliorated the injury-induced decrease in media NO levels, iNOS expression and inflammatory associated gene expression. Additionally, treatment alleviated morphological changes observed after stretch-injury and restored normal migratory behavior to control levels. Taken together, these data suggest that the integrin/FAK pathway partially mediates the stretch-injured phenotype in microglia, and may serve as a pathway to modulate microglial responses.
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Affiliation(s)
- Michael C Shaughness
- Neuroscience Program, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Rd., Bethesda, MD, 20814, USA.,Operational and Undersea Medicine Directorate (OUMD), En Route & Critical Care Department (ECD), Naval Medical Research Center (NMRC), Silver Spring, MD, USA
| | - Nathan Pierron
- F.E. Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Austin N Smith
- Neuroscience Program, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Rd., Bethesda, MD, 20814, USA
| | - Kimberly R Byrnes
- Neuroscience Program, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Rd., Bethesda, MD, 20814, USA. .,Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
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Varghese N, Morrison B. Partial Depletion of Microglia Attenuates Long-Term Potentiation Deficits following Repeated Blast Traumatic Brain Injury in Organotypic Hippocampal Slice Cultures. J Neurotrauma 2023; 40:547-560. [PMID: 36508265 PMCID: PMC10081725 DOI: 10.1089/neu.2022.0284] [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] [Indexed: 12/14/2022] Open
Abstract
Blast-induced traumatic brain injury (bTBI) has been a health concern in both military and civilian populations due to recent military and geopolitical conflicts. Military service members are frequently exposed to repeated bTBI throughout their training and deployment. Our group has previously reported compounding functional deficits as a result of increased number of blast exposures. In this study, we further characterized the decrease in long-term potentiation (LTP) by varying the blast injury severity and the inter-blast interval between two blast exposures. LTP deficits were attenuated with increasing inter-blast intervals. We also investigated changes in microglial activation; expression of CD68 was increased and expression of CD206 was decreased after multiple blast exposures. Expression of macrophage inflammatory protein (MIP)-1α, interleukin (IL)-1β, monocyte chemoattractant protein (MCP)-1, interferon gamma-inducible protein (IP)-10, and regulated on activation, normal T cell expressed and secreted (RANTES) increased, while expression of IL-10 decreased in the acute period after both single and repeated bTBI. By partially depleting microglia prior to injury, LTP deficits after injury were significantly reduced. Treatment with the novel drug, MW-189, prevented LTP deficits when administered immediately following a repeated bTBI and even when administered only for an acute period (24 h) between two blast injuries. These findings could inform the development of therapeutic strategies to treat the neurological deficits of repeated bTBI suggesting that microglia play a major role in functional neuronal deficits and may be a viable therapeutic target to lessen the neurophysiological deficits after bTBI.
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Affiliation(s)
- Nevin Varghese
- Department of Biomedical Engineering, Columbia University, New York, New York, USA
| | - Barclay Morrison
- Department of Biomedical Engineering, Columbia University, New York, New York, USA
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Modeling Central Nervous System Injury In Vitro: Current Status and Promising Future Strategies. Biomedicines 2022; 11:biomedicines11010094. [PMID: 36672601 PMCID: PMC9855387 DOI: 10.3390/biomedicines11010094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/19/2022] [Accepted: 12/25/2022] [Indexed: 12/31/2022] Open
Abstract
The central nervous system (CNS) injury, which occurs because of mechanical trauma or ischemia/hypoxia, is one of the main causes of mortality and morbidity in the modern society. Until know, despite the fact that numerous preclinical and clinical studies have been undertaken, no significant neuroprotective strategies have been discovered that could be used in the brain trauma or ischemia treatment. Although there are many potential explanations for the failure of those studies, it is clear that there are questions regarding the use of experimental models, both in vivo and in vitro, when studying CNS injury and searching new therapeutics. Due to some ethical issues with the use of live animals in biomedical research, implementation of experimental strategies that prioritize the use of cells and tissues in the in vitro environment has been encouraged. In this review, we examined some of the most commonly used in vitro models and the most frequently utilized cellular platforms in the research of traumatic brain injury and cerebral ischemia. We also proposed some future strategies that could improve the usefulness of these studies for better bench-to-bedside translational outcomes.
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