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Ritter K, Vetter D, Wernersbach I, Schwanz T, Hummel R, Schäfer MKE. Pre-traumatic antibiotic-induced microbial depletion reduces neuroinflammation in acute murine traumatic brain injury. Neuropharmacology 2023:109648. [PMID: 37385435 DOI: 10.1016/j.neuropharm.2023.109648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 06/05/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
The connection between dysbiosis of the gut microbiome and diseases and injuries of the brain has attracted considerable interest in recent years. Interestingly, antibiotic-induced microbial dysbiosis has been implicated in the pathogenesis of traumatic brain injury (TBI), while early administration of antibiotics associates with improved survival in TBI patients. In animal models of TBI, short- or long-term administration of antibiotics, both peri- or post-operatively, were shown to induce gut microbiome dysbiosis but also anti-inflammatory and neuroprotective effects. However, the acute consequences of microbial dysbiosis on TBI pathogenesis after discontinuation of antibiotic treatment are elusive. In this study, we tested whether pre-traumatic antibiotic-induced microbial depletion by vancomycin, amoxicillin, and clavulanic acid affects pathogenesis during the acute phase of TBI in adult male C57BL/6 mice. Pre-traumatic microbiome depletion did not affect neurological deficits over 72 h post injury (hpi) and brain histopathology, including numbers of activated astrocytes and microglia, at 72 hpi. However, astrocytes and microglia were smaller after pre-traumatic microbiome depletion compared to vehicle treatment at 72hpi, indicating less inflammatory activation. Accordingly, TBI-induced gene expression of the inflammation markers Interleukin-1β, complement component C3, translocator protein TSPO and the major histocompatibility complex MHC2 was attenuated in microbiome-depleted mice along with reduced Immunoglobulin G extravasation as a proxy of blood-brain barrier (BBB) impairment. These results suggest that the gut microbiome contributes to early neuroinflammatory responses to TBI but does not have a significant impact on brain histopathology and neurological deficits.
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Affiliation(s)
- Katharina Ritter
- Department of Anesthesiology, University Medical Center of the Johannes-Gutenberg-University, Mainz, Germany.
| | - Diana Vetter
- Department of Anesthesiology, University Medical Center of the Johannes-Gutenberg-University, Mainz, Germany.
| | - Isa Wernersbach
- Department of Anesthesiology, University Medical Center of the Johannes-Gutenberg-University, Mainz, Germany.
| | - Thomas Schwanz
- Department of Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg-University Mainz, Germany.
| | - Regina Hummel
- Department of Anesthesiology, University Medical Center of the Johannes-Gutenberg-University, Mainz, Germany.
| | - Michael K E Schäfer
- Department of Anesthesiology, University Medical Center of the Johannes-Gutenberg-University, Mainz, Germany; Research Center for Immunotherapy (FZI), Germany; Focus Program Translational Neurosciences (FTN), Germany.
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Wang Y, Wernersbach I, Strehle J, Li S, Appel D, Klein M, Ritter K, Hummel R, Tegeder I, Schäfer MKE. Early posttraumatic CSF1R inhibition via PLX3397 leads to time- and sex-dependent effects on inflammation and neuronal maintenance after traumatic brain injury in mice. Brain Behav Immun 2022; 106:49-66. [PMID: 35933030 DOI: 10.1016/j.bbi.2022.07.164] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/08/2022] [Accepted: 07/30/2022] [Indexed: 10/31/2022] Open
Abstract
BACKGROUND There is a need for early therapeutic interventions after traumatic brain injury (TBI) to prevent neurodegeneration. Microglia/macrophage (M/M) depletion and repopulation after treatment with colony stimulating factor 1 receptor (CSF1R) inhibitors reduces neurodegeneration. The present study investigates short- and long-term consequences after CSF1R inhibition during the early phase after TBI. METHODS Sex-matched mice were subjected to TBI and CSF1R inhibition by PLX3397 for 5 days and sacrificed at 5 or 30 days post injury (dpi). Neurological deficits were monitored and brain tissues were examined for histo- and molecular pathological markers. RNAseq was performed with 30 dpi TBI samples. RESULTS At 5 dpi, CSF1R inhibition attenuated the TBI-induced perilesional M/M increase and associated gene expressions by up to 50%. M/M attenuation did not affect structural brain damage at this time-point, impaired hematoma clearance, and had no effect on IL-1β expression. At 30 dpi, following drug discontinuation at 5 dpi and M/M repopulation, CSF1R inhibition attenuated brain tissue loss regardless of sex, as well as hippocampal atrophy and thalamic neuronal loss in male mice. Selected gene markers of brain inflammation and apoptosis were reduced in males but increased in females after early CSF1R inhibition as compared to corresponding TBI vehicle groups. Neurological outcome in behaving mice was almost not affected. RNAseq and gene set enrichment analysis (GSEA) of injured brains at 30 dpi revealed more genes associated with dendritic spines and synapse function after early CSF1R inhibition as compared to vehicle, suggesting improved neuronal maintenance and recovery. In TBI vehicle mice, GSEA showed high oxidative phosphorylation, oxidoreductase activity and ribosomal biogenesis suggesting oxidative stress and increased abundance of metabolically highly active cells. More genes associated with immune processes and phagocytosis in PLX3397 treated females vs males, suggesting sex-specific differences in response to early CSF1R inhibition after TBI. CONCLUSIONS M/M attenuation after CSF1R inhibition via PLX3397 during the early phase of TBI reduces long-term brain tissue loss, improves neuronal maintenance and fosters synapse recovery. Overall effects were not sex-specific but there is evidence that male mice benefit more than female mice.
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Affiliation(s)
- Yong Wang
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Isa Wernersbach
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Jenny Strehle
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Shuailong Li
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Dominik Appel
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Matthias Klein
- Institute for Immunology, University Medical Center, Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Katharina Ritter
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Regina Hummel
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany
| | - Irmgard Tegeder
- Institute of Clinical Pharmacology, Goethe-University Frankfurt, Medical Faculty, Theodor Stern Kai 7, 60590 Frankfurt, Germany
| | - Michael K E Schäfer
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany; Focus Program Translational Neurosciences (FTN) of the Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany; Research Center for Immunotherapy (FZI), Johannes Gutenberg-University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany.
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Li S, Wernersbach I, Harms GS, Schäfer MKE. Microglia subtypes show substrate- and time-dependent phagocytosis preferences and phenotype plasticity. Front Immunol 2022. [PMID: 36105813 DOI: 10.3389/fimmu.2022b.945485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
Microglia are phagocytosis-competent CNS cells comprising a spectrum of subtypes with beneficial and/or detrimental functions in acute and chronic neurodegenerative disorders. The heterogeneity of microglia suggests differences in phagocytic activity and phenotype plasticity between microglia subtypes. To study these issues, primary murine glial cultures were cultivated in the presence of serum, different growth factors and cytokines to obtain M0-like, M1-like, and M2-like microglia as confirmed by morphology, M1/M2 gene marker expression, and nitric oxide assay. Single-cell analysis after 3 hours of phagocytosis of E.coli particles or IgG-opsonized beads showed equal internalization by M0-like microglia, whereas M1-like microglia preferably internalized E.coli particles and M2-like microglia preferably internalized IgG beads, suggesting subtype-specific preferences for different phagocytosis substrates. Time-lapse live-cells imaging over 16 hours revealed further differences between microglia subtypes in phagocytosis preference and internalization dynamics. M0- and, more efficiently, M1-like microglia continuously internalized E.coli particles for 16 hours, whereas M2-like microglia discontinued internalization after approximately 8 hours. IgG beads were continuously internalized by M0- and M1-like microglia but strikingly less by M2-like microglia. M2-like microglia initially showed continuous internalization similar to M0-like microglia but again discontinuation of internalization after 8 hours suggesting that the time of substrate exposure differently affect microglia subtypes. After prolonged exposure to E.coli particles or IgG beads for 5 days all microglia subtypes showed increased internalization of E.coli particles compared to IgG beads, increased nitric oxide release and up-regulation of M1 gene markers, irrespectively of the phagocytosis substrate, suggesting phenotype plasticity. In summary, microglia subtypes show substrate- and time-dependent phagocytosis preferences and phenotype plasticity. The results suggest that prolonged phagocytosis substrate exposure enhances M1-like profiles and M2-M1 repolarization of microglia. Similar processes may also take place in conditions of acute and chronic brain insults when microglia encounter different types of phagocytic substrates.
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Affiliation(s)
- Shuailong Li
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Isa Wernersbach
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Gregory S Harms
- Cell Biology Unit, University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany.,Departments of Biology and Physics, Wilkes University, Wilkes Barre, PA, United States
| | - Michael K E Schäfer
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany.,Focus Program Translational Neurosciences (FTN), Johannes Gutenberg-University Mainz, Mainz, Germany.,Research Center for Immunotherapy (FZI), University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany
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Li S, Wernersbach I, Harms GS, Schäfer MKE. Microglia subtypes show substrate- and time-dependent phagocytosis preferences and phenotype plasticity. Front Immunol 2022; 13:945485. [PMID: 36105813 PMCID: PMC9465456 DOI: 10.3389/fimmu.2022.945485] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/04/2022] [Indexed: 11/16/2022] Open
Abstract
Microglia are phagocytosis-competent CNS cells comprising a spectrum of subtypes with beneficial and/or detrimental functions in acute and chronic neurodegenerative disorders. The heterogeneity of microglia suggests differences in phagocytic activity and phenotype plasticity between microglia subtypes. To study these issues, primary murine glial cultures were cultivated in the presence of serum, different growth factors and cytokines to obtain M0-like, M1-like, and M2-like microglia as confirmed by morphology, M1/M2 gene marker expression, and nitric oxide assay. Single-cell analysis after 3 hours of phagocytosis of E.coli particles or IgG-opsonized beads showed equal internalization by M0-like microglia, whereas M1-like microglia preferably internalized E.coli particles and M2-like microglia preferably internalized IgG beads, suggesting subtype-specific preferences for different phagocytosis substrates. Time-lapse live-cells imaging over 16 hours revealed further differences between microglia subtypes in phagocytosis preference and internalization dynamics. M0- and, more efficiently, M1-like microglia continuously internalized E.coli particles for 16 hours, whereas M2-like microglia discontinued internalization after approximately 8 hours. IgG beads were continuously internalized by M0- and M1-like microglia but strikingly less by M2-like microglia. M2-like microglia initially showed continuous internalization similar to M0-like microglia but again discontinuation of internalization after 8 hours suggesting that the time of substrate exposure differently affect microglia subtypes. After prolonged exposure to E.coli particles or IgG beads for 5 days all microglia subtypes showed increased internalization of E.coli particles compared to IgG beads, increased nitric oxide release and up-regulation of M1 gene markers, irrespectively of the phagocytosis substrate, suggesting phenotype plasticity. In summary, microglia subtypes show substrate- and time-dependent phagocytosis preferences and phenotype plasticity. The results suggest that prolonged phagocytosis substrate exposure enhances M1-like profiles and M2-M1 repolarization of microglia. Similar processes may also take place in conditions of acute and chronic brain insults when microglia encounter different types of phagocytic substrates.
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Affiliation(s)
- Shuailong Li
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Isa Wernersbach
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Gregory S. Harms
- Cell Biology Unit, University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany
- Departments of Biology and Physics, Wilkes University, Wilkes Barre, PA, United States
| | - Michael K. E. Schäfer
- Department of Anesthesiology, University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany
- Focus Program Translational Neurosciences (FTN), Johannes Gutenberg-University Mainz, Mainz, Germany
- Research Center for Immunotherapy (FZI), University Medical Center, Johannes Gutenberg-University Mainz, Mainz, Germany
- *Correspondence: Michael K. E. Schäfer,
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Mais CN, Hermann L, Altegoer F, Seubert A, Richter AA, Wernersbach I, Czech L, Bremer E, Bange G. Degradation of the microbial stress protectants and chemical chaperones ectoine and hydroxyectoine by a bacterial hydrolase-deacetylase complex. J Biol Chem 2020; 295:9087-9104. [PMID: 32404365 PMCID: PMC7335791 DOI: 10.1074/jbc.ra120.012722] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 05/06/2020] [Indexed: 12/12/2022] Open
Abstract
When faced with increased osmolarity in the environment, many bacterial cells accumulate the compatible solute ectoine and its derivative 5-hydroxyectoine. Both compounds are not only potent osmostress protectants, but also serve as effective chemical chaperones stabilizing protein functionality. Ectoines are energy-rich nitrogen and carbon sources that have an ecological impact that shapes microbial communities. Although the biochemistry of ectoine and 5-hydroxyectoine biosynthesis is well understood, our understanding of their catabolism is only rudimentary. Here, we combined biochemical and structural approaches to unravel the core of ectoine and 5-hydroxy-ectoine catabolisms. We show that a conserved enzyme bimodule consisting of the EutD ectoine/5-hydroxyectoine hydrolase and the EutE deacetylase degrades both ectoines. We determined the high-resolution crystal structures of both enzymes, derived from the salt-tolerant bacteria Ruegeria pomeroyi and Halomonas elongata These structures, either in their apo-forms or in forms capturing substrates or intermediates, provided detailed insights into the catalytic cores of the EutD and EutE enzymes. The combined biochemical and structural results indicate that the EutD homodimer opens the pyrimidine ring of ectoine through an unusual covalent intermediate, N-α-2 acetyl-l-2,4-diaminobutyrate (α-ADABA). We found that α-ADABA is then deacetylated by the zinc-dependent EutE monomer into diaminobutyric acid (DABA), which is further catabolized to l-aspartate. We observed that the EutD-EutE bimodule synthesizes exclusively the α-, but not the γ-isomers of ADABA or hydroxy-ADABA. Of note, α-ADABA is known to induce the MocR/GabR-type repressor EnuR, which controls the expression of many ectoine catabolic genes clusters. We conclude that hydroxy-α-ADABA might serve a similar function.
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Affiliation(s)
- Christopher-Nils Mais
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany
| | - Lucas Hermann
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany
| | - Florian Altegoer
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany
| | - Andreas Seubert
- Philipps-University Marburg, Faculty of Chemistry, Marburg, Germany
| | - Alexandra A Richter
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany
| | - Isa Wernersbach
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany
| | - Laura Czech
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany
| | - Erhard Bremer
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Biology, Marburg, Germany.
| | - Gert Bange
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) & Faculty of Chemistry, Marburg, Germany.
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