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Nikodemova M, Oberto JR, Berschel MR, Michaelson AL, Watters JJ, Mitchell GS. Acute Postnatal Inflammation Alters Adult Microglial Responses to LPS that Are Sex-, Region- and Timing of Postnatal Inflammation-Dependent. RESEARCH SQUARE 2024:rs.3.rs-4565866. [PMID: 38978595 PMCID: PMC11230508 DOI: 10.21203/rs.3.rs-4565866/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
BACKGROUND Adverse events in early life can have impact lasting into adulthood. We investigated the long-term effects of systemic inflammation during postnatal development on adult microglial responses to LPS in two CNS regions (cortex, cervical spinal cord) in male and female rats. METHODS Inflammation was induced in Sprague-Dawley rats by lipopolysaccharide (LPS, 1 mg/kg) administered intraperitoneally during postnatal development at P7, P12 or P18. As adults (12 weeks of age), the rats received a second LPS dose (1 mg/kg). Control rats received saline. Microglia were isolated 3 hours post-LPS from the cortex and cervical spinal cord. Gene expression was assessed via qRT-PCR for pro-inflammatory (IL-6, iNOS, Ptgs2, C/EBPb, CD14, CXCL10), anti-inflammatory (CD68, Arg-1), and homeostatic genes (P2Y12, Tmemm119). CSF-1 and CX3CL1 mRNA was analyzed in microglia-free homogenates. RESULTS Basal gene expression in adult microglia was largely unaffected by early life LPS. Changes in adult microglial pro-inflammatory genes in response to LPS were either unchanged or attenuated in rats exposed to LPS during postnatal development. Ptgs2, C/EBPb, CXCL10 and Arg-1 were the genes most affected, with expression levels significantly downregulated vs control rats without postnatal LPS exposure. Cortical microglia were affected more by postnatal inflammation than spinal microglia, and males were more impacted than females. Overall, inflammatory challenge at P18 had the greatest effect on adult microglial gene expression, whereas challenge at P7 had less impact. Microglial homeostatic genes were unaffected by postnatal LPS. CONCLUSIONS Long-lasting effects of postnatal inflammation on adult microglia depend on the timing of postnatal inflammation, CNS region and sex.
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Fang P, Yu LW, Espey H, Agirman G, Kazmi SA, Li K, Deng Y, Lee J, Hrncir H, Romero-Lopez A, Arnold AP, Hsiao EY. Sex-dependent interactions between prodromal intestinal inflammation and LRRK2 G2019S in mice promote endophenotypes of Parkinson's disease. Commun Biol 2024; 7:570. [PMID: 38750146 PMCID: PMC11096388 DOI: 10.1038/s42003-024-06256-9] [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: 02/29/2024] [Accepted: 04/26/2024] [Indexed: 05/18/2024] Open
Abstract
Gastrointestinal (GI) disruptions and inflammatory bowel disease (IBD) are commonly associated with Parkinson's disease (PD), but how they may impact risk for PD remains poorly understood. Herein, we provide evidence that prodromal intestinal inflammation expedites and exacerbates PD endophenotypes in rodent carriers of the human PD risk allele LRRK2 G2019S in a sex-dependent manner. Chronic intestinal damage in genetically predisposed male mice promotes α-synuclein aggregation in the substantia nigra, loss of dopaminergic neurons and motor impairment. This male bias is preserved in gonadectomized males, and similarly conferred by sex chromosomal complement in gonadal females expressing human LRRK2 G2019S. The early onset and heightened severity of neuropathological and behavioral outcomes in male LRRK2 G2019S mice is preceded by increases in α-synuclein in the colon, α-synuclein-positive macrophages in the colonic lamina propria, and loads of phosphorylated α-synuclein within microglia in the substantia nigra. Taken together, these data reveal that prodromal intestinal inflammation promotes the pathogenesis of PD endophenotypes in male carriers of LRRK2 G2019S, through mechanisms that depend on genotypic sex and involve early accumulation of α-synuclein in myeloid cells within the gut.
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Affiliation(s)
- Ping Fang
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
| | - Lewis W Yu
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Hannah Espey
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Gulistan Agirman
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Sabeen A Kazmi
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Kai Li
- F. Widjaja Foundation Inflammatory Bowel & Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
- Research Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
| | - Yongning Deng
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Jamie Lee
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Haley Hrncir
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Arlene Romero-Lopez
- UCLA Goodman-Luskin Microbiome Center, Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, Los Angeles, CA, 90095, USA
| | - Arthur P Arnold
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Elaine Y Hsiao
- Department of Integrative Biology & Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
- UCLA Goodman-Luskin Microbiome Center, Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, Los Angeles, CA, 90095, USA.
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
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Ong RCS, Beros JL, Fuller K, Wood FM, Melton PE, Rodger J, Fear MW, Barrett L, Stevenson AW, Tang AD. Non-severe thermal burn injuries induce long-lasting downregulation of gene expression in cortical excitatory neurons and microglia. Front Mol Neurosci 2024; 17:1368905. [PMID: 38476460 PMCID: PMC10927825 DOI: 10.3389/fnmol.2024.1368905] [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: 01/11/2024] [Accepted: 02/12/2024] [Indexed: 03/14/2024] Open
Abstract
Burn injuries are devastating traumas, often leading to life-long consequences that extend beyond the observable burn scar. In the context of the nervous system, burn injury patients commonly develop chronic neurological disorders and have been suggested to have impaired motor cortex function, but the long-lasting impact on neurons and glia in the brain is unknown. Using a mouse model of non-severe burn injury, excitatory and inhibitory neurons in the primary motor cortex were labelled with fluorescent proteins using adeno-associated viruses (AAVs). A total of 5 weeks following the burn injury, virus labelled excitatory and inhibitory neurons were isolated using fluorescence-activated cell sorting (FACS). In addition, microglia and astrocytes from the remaining cortical tissue caudal to the motor cortex were immunolabelled and isolated with FACS. Whole transcriptome RNA-sequencing was used to identify any long-lasting changes to gene expression in the different cell types. RNA-seq analysis showed changes to the expression of a small number of genes with known functions in excitatory neurons and microglia, but not in inhibitory neurons or astrocytes. Specifically, genes related to GABA-A receptors in excitatory neurons and several cellular functions in microglia were found to be downregulated in burn injured mice. These findings suggest that non-severe burn injuries lead to long lasting transcriptomic changes in the brain, but only in specific cell types. Our findings provide a broad overview of the long-lasting impact of burn injuries on the central nervous system which may help identify potential therapeutic targets to prevent neurological dysfunction in burn patients.
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Affiliation(s)
- Rebecca C. S. Ong
- Experimental and Regenerative Neuroscience, The University of Western Australia, Crawley, WA, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA, Australia
| | - Jamie L. Beros
- Experimental and Regenerative Neuroscience, The University of Western Australia, Crawley, WA, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA, Australia
| | - Kathy Fuller
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Fiona M. Wood
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
- Burn Injury Research Unit, The University of Western Australia, Crawley, WA, Australia
- Burns Service of Western Australia, WA Department of Health, Murdoch, WA, Australia
- Paediatric Burn Care, Telethon Kids Institute, Nedlands, WA, Australia
| | - Phillip E. Melton
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
- School of Global and Population Health, The University of Western Australia, Crawley, WA, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neuroscience, The University of Western Australia, Crawley, WA, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA, Australia
| | - Mark W. Fear
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Lucy Barrett
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
- Burn Injury Research Unit, The University of Western Australia, Crawley, WA, Australia
- Burns Service of Western Australia, WA Department of Health, Murdoch, WA, Australia
| | - Andrew W. Stevenson
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
- Burn Injury Research Unit, The University of Western Australia, Crawley, WA, Australia
| | - Alexander D. Tang
- Experimental and Regenerative Neuroscience, The University of Western Australia, Crawley, WA, Australia
- Perron Institute for Neurological and Translational Sciences, Nedlands, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Crawley, WA, Australia
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Bobotis BC, Halvorson T, Carrier M, Tremblay MÈ. Established and emerging techniques for the study of microglia: visualization, depletion, and fate mapping. Front Cell Neurosci 2024; 18:1317125. [PMID: 38425429 PMCID: PMC10902073 DOI: 10.3389/fncel.2024.1317125] [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: 10/10/2023] [Accepted: 01/15/2024] [Indexed: 03/02/2024] Open
Abstract
The central nervous system (CNS) is an essential hub for neuronal communication. As a major component of the CNS, glial cells are vital in the maintenance and regulation of neuronal network dynamics. Research on microglia, the resident innate immune cells of the CNS, has advanced considerably in recent years, and our understanding of their diverse functions continues to grow. Microglia play critical roles in the formation and regulation of neuronal synapses, myelination, responses to injury, neurogenesis, inflammation, and many other physiological processes. In parallel with advances in microglial biology, cutting-edge techniques for the characterization of microglial properties have emerged with increasing depth and precision. Labeling tools and reporter models are important for the study of microglial morphology, ultrastructure, and dynamics, but also for microglial isolation, which is required to glean key phenotypic information through single-cell transcriptomics and other emerging approaches. Strategies for selective microglial depletion and modulation can provide novel insights into microglia-targeted treatment strategies in models of neuropsychiatric and neurodegenerative conditions, cancer, and autoimmunity. Finally, fate mapping has emerged as an important tool to answer fundamental questions about microglial biology, including their origin, migration, and proliferation throughout the lifetime of an organism. This review aims to provide a comprehensive discussion of these established and emerging techniques, with applications to the study of microglia in development, homeostasis, and CNS pathologies.
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Affiliation(s)
- Bianca Caroline Bobotis
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Centre for Advanced Materials and Related Technology, Victoria, BC, Canada
| | - Torin Halvorson
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
- Department of Surgery, University of British Columbia, Vancouver, BC, Canada
- British Columbia Children’s Hospital Research Institute, Vancouver, BC, Canada
| | - Micaël Carrier
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Département de Psychiatrie et de Neurosciences, Faculté de Médecine, Université Laval, Québec City, QC, Canada
- Axe neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Centre for Advanced Materials and Related Technology, Victoria, BC, Canada
- Axe neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
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Akhmetzyanova ER, Rizvanov AA, Mukhamedshina YO. Current methods for the microglia isolation: Overview and comparative analysis of approaches. Cell Tissue Res 2024; 395:147-158. [PMID: 38099956 DOI: 10.1007/s00441-023-03853-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 12/01/2023] [Indexed: 02/03/2024]
Abstract
Microglia represent a distinct population of neuroglia, constituting ~ 10% of all CNS cells and exhibit high plasticity. Proper functioning of microglia is critical in the event of CNS damage due to the rapid modulation of their functions. Microglia are not only the first stage of immune defense against injury and infection, contributing to both the innate and adaptive local immune response, but also play a vital role in maintaining homeostasis of the brain and spinal cord. For this reason, microglia deserve special attention in the study of neuropathological responses. Studying microglia behavior in various in vivo models of neuropathologies is certainly a priority, as it allows us to evaluate the behavior in the context of the changing microenvironment of nervous tissue. However, sometimes there are some technological problems that hinder the identification of the features of intercellular interactions, ensured cooperation between microglia and other cell types. In this regard, the use of in vitro models remains relevant today, contributing to a more in-depth understanding of the mechanisms of microglial involvement in neuropathology. The methods considered in this review for obtaining an isolated culture of microglia, along with their advantages and disadvantages, can help researchers in selecting the appropriate source and method for obtaining these cells, thereby opening up opportunities for gaining new neurobiological knowledge.
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Affiliation(s)
- E R Akhmetzyanova
- OpenLab Gene and Cell Technology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008, Kazan, Russia.
| | - A A Rizvanov
- OpenLab Gene and Cell Technology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008, Kazan, Russia
| | - Y O Mukhamedshina
- OpenLab Gene and Cell Technology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008, Kazan, Russia
- Department of Histology, Cytology, and Embryology, Kazan State Medical University, 420012, Kazan, Russia
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6
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Hu NY, Gao TM, Chen YH. Preparation of Healthy Single Neuron or Astrocyte Suspension from Adult Mouse Brain for RNA-seq. Methods Mol Biol 2024; 2794:341-351. [PMID: 38630243 DOI: 10.1007/978-1-0716-3810-1_29] [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] [Indexed: 04/19/2024]
Abstract
Single-cell RNA sequencing (scRNA-seq) has been widely applied in neuroscience research, enabling the investigation of cellular heterogeneity at the transcriptional level, the characterization of rare cell types, and the detailed analysis of the stochastic nature of gene expression. Isolation of single nerve cells in good health, especially from the adult rodent brain, is the most difficult and critical process for scRNA-seq. Here, we describe methods to optimize protease digestion of brain slices, which enable yield of millions of cells in good health from the adult brain.
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Affiliation(s)
- Neng-Yuan Hu
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong Joint Laboratory for Psychiatric Disorders, Guangdong Province Key Laboratory of Psychiatric Disorders, Guangdong Basic Research Center of Excellence for Integrated Traditional and Western Medicine for Qingzhi Diseases, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Tian-Ming Gao
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong Joint Laboratory for Psychiatric Disorders, Guangdong Province Key Laboratory of Psychiatric Disorders, Guangdong Basic Research Center of Excellence for Integrated Traditional and Western Medicine for Qingzhi Diseases, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
| | - Yi-Hua Chen
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong Joint Laboratory for Psychiatric Disorders, Guangdong Province Key Laboratory of Psychiatric Disorders, Guangdong Basic Research Center of Excellence for Integrated Traditional and Western Medicine for Qingzhi Diseases, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
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7
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King'uyu DN, Nti-Kyemereh L, Bonin JL, Feustel PJ, Tram M, MacNamara KC, Kopec AM. The effect of morphine on rat microglial phagocytic activity: An in vitro study of brain region-, plating density-, sex-, morphine concentration-, and receptor-dependency. J Neuroimmunol 2023; 384:578204. [PMID: 37774553 DOI: 10.1016/j.jneuroim.2023.578204] [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: 04/07/2023] [Revised: 07/24/2023] [Accepted: 09/19/2023] [Indexed: 10/01/2023]
Abstract
Opioids have long been used for clinical pain management, but also have addictive properties that have contributed to the ongoing opioid epidemic. While opioid activation of opioid receptors is well known to contribute to reward and reinforcement, data now also suggest that opioid activation of immune signaling via toll-like receptor 4 (TLR4) may also play a role in addiction-like processes. TLR4 expression is enriched in immune cells, and in the nervous system is primarily expressed in microglia. Microglial phagocytosis is important for developmental, homeostatic, and pathological processes. To examine how morphine impacts microglial phagocytosis, we isolated microglia from adult male and female rat cortex and striatum and plated them in vitro at 10,000 (10K) or 50,000 cells/well densities. Microglia were incubated with neutral fluorescent microbeads to stimulate phagocytosis in the presence of one of four morphine concentrations. We found that the brain region from which microglia are isolated and plating density, but not morphine concentration, impacts cell survival in vitro. We found that 10-12 M morphine, but not higher concentrations, increases phagocytosis in striatal microglia in vitro independent of sex and plating density, while 10-12 M morphine increased phagocytosis in cortical microglia in vitro independent of sex, but contingent on a plating density. Finally, we demonstrate that the effect of 10-12 M morphine in striatal microglia plated at 10 K density is mediated via TLR4, and not μORs. Overall, our data suggest that in rats, a morphine-TLR4 signaling pathway increases phagocytic activity in microglia independent of sex. This may is useful information for better understanding the possible neural outcomes associated with morphine exposures.
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Affiliation(s)
- David N King'uyu
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, United States of America.
| | - Lily Nti-Kyemereh
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, United States of America; Siena College, Loudonville, NY 12211, United States of America
| | - Jesse L Bonin
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY 12208, United States of America
| | - Paul J Feustel
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, United States of America
| | - Michelle Tram
- Siena College, Loudonville, NY 12211, United States of America
| | - Katherine C MacNamara
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY 12208, United States of America
| | - Ashley M Kopec
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, United States of America
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8
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Chakrabarti S, Gorai S, Pahan K. A simple protocol for isolating microglia from adult mouse brain. NEUROIMMUNE PHARMACOLOGY AND THERAPEUTICS 2023; 2:293-300. [PMID: 37885917 PMCID: PMC10474378 DOI: 10.1515/nipt-2023-0014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 07/20/2023] [Indexed: 10/28/2023]
Abstract
Objectives Although microglia are activated in adult and aged brains resulting in neurodegenerative and neuroinflammatory disorders, most of the cell culture studies on microglia deal with neonatal microglia because of ease of isolation. Microglia could be isolated from adult brains, but it requires separation by density gradient centrifugation, magnetic beads, etc. Here, we describe a simple protocol of isolating highly purified microglia from adult mouse brains. Methods Our protocol involves dilution with sterile PBS or media, regular centrifugation, and plating on poly-D-lysine-coated flasks. Results These adult microglia expressed the inducible nitric oxide synthase in response to preformed α-syn fibril, an etiological reagent of Parkinson's disease, and bacterial lipopolysaccharides, one of the prototype proinflammatory stimuli. Moreover, these adult microglia exhibited phagocytosis, which was stimulated by LPS treatment. Conclusions These results suggest that adult microglia isolated by our procedure are functional and that these adult microglia could be used for studies related to neurodegenerative disorders.
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Affiliation(s)
- Sudipta Chakrabarti
- Department of Neurological Sciences, Rush University Medical Center, Chicago, USA
| | - Sukhamoy Gorai
- Department of Neurological Sciences, Rush University Medical Center, Chicago, USA
| | - Kalipada Pahan
- Department of Neurological Sciences, Rush University Medical Center, Chicago, USA
- Division of Research and Development, Jesse Brown Veterans Affairs Medical Center, Chicago, USA
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9
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Caetano-Silva ME, Rund L, Hutchinson NT, Woods JA, Steelman AJ, Johnson RW. Inhibition of inflammatory microglia by dietary fiber and short-chain fatty acids. Sci Rep 2023; 13:2819. [PMID: 36797287 PMCID: PMC9935636 DOI: 10.1038/s41598-022-27086-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/26/2022] [Indexed: 02/18/2023] Open
Abstract
Microglia play a vital role maintaining brain homeostasis but can also cause persistent neuroinflammation. Short-chain fatty acids (SCFAs) produced by the intestinal microbiota have been suggested to regulate microglia inflammation indirectly by signaling through the gut-brain axis or directly by reaching the brain. The present work evaluated the anti-inflammatory effects of SCFAs on lipopolysaccharide (LPS)-stimulated microglia from mice fed inulin, a soluble fiber that is fermented by intestinal microbiota to produce SCFAs in vivo, and SCFAs applied to primary microglia in vitro. Feeding mice inulin increased SCFAs in the cecum and in plasma collected from the hepatic portal vein. Microglia isolated from mice fed inulin and stimulated with LPS in vitro secreted less tumor necrosis factor α (TNF-α) compared to microglia from mice not given inulin. Additionally, when mice were fed inulin and injected i.p with LPS, the ex vivo secretion of TNF-α by isolated microglia was lower than that secreted by microglia from mice not fed inulin and injected with LPS. Similarly, in vitro treatment of primary microglia with acetate and butyrate either alone or in combination downregulated microglia cytokine production with the effects being additive. SCFAs reduced histone deacetylase activity and nuclear factor-κB nuclear translocation after LPS treatment in vitro. Whereas microglia expression of SCFA receptors Ffar2 or Ffar3 was not detected by single-cell RNA sequencing analysis, the SCFA transporters Mct1 and Mct4 were. Nevertheless, inhibiting monocarboxylate transporters on primary microglia did not interfere with the anti-inflammatory effects of SCFAs, suggesting that if SCFAs produced in the gut regulate microglia directly it is likely through an epigenetic mechanism following diffusion.
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Affiliation(s)
| | - Laurie Rund
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Noah T Hutchinson
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jeffrey A Woods
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Andrew J Steelman
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Rodney W Johnson
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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Agosto-Marlin IM, Nikodemova M, Dale EA, Mitchell GS. BDNF-induced phrenic motor facilitation shifts from PKCθ to ERK dependence with mild systemic inflammation. J Neurophysiol 2023; 129:455-464. [PMID: 36695529 PMCID: PMC9942899 DOI: 10.1152/jn.00345.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023] Open
Abstract
Moderate acute intermittent hypoxia (mAIH) elicits a form of phrenic motor plasticity known as phrenic long-term facilitation (pLTF), which requires spinal 5-HT2 receptor activation, ERK/MAP kinase signaling, and new brain-derived neurotrophic factor (BDNF) synthesis. New BDNF protein activates TrkB receptors that normally signal through PKCθ to elicit pLTF. Phrenic motor plasticity elicited by spinal drug administration (e.g., BDNF) is referred to by a more general term: phrenic motor facilitation (pMF). Although mild systemic inflammation elicited by a low lipopolysaccharide (LPS) dose (100 µg/kg; 24 h prior) undermines mAIH-induced pLTF upstream from BDNF protein synthesis, it augments pMF induced by spinal BDNF administration through unknown mechanisms. Here, we tested the hypothesis that mild inflammation shifts BDNF/TrkB signaling from PKCθ to alternative pathways that enhance pMF. We examined the role of three known signaling pathways associated with TrkB (MEK/ERK MAP kinase, PI3 kinase/Akt, and PKCθ) in BDNF-induced pMF in anesthetized, paralyzed, and ventilated Sprague Dawley rats 24 h post-LPS. Spinal PKCθ inhibitor (TIP) attenuated early BDNF-induced pMF (≤30 min), with minimal effect 60-90 min post-BDNF injection. In contrast, MEK inhibition (U0126) abolished BDNF-induced pMF at 60 and 90 min. PI3K/Akt inhibition (PI-828) had no effect on BDNF-induced pMF at any time. Thus, whereas BDNF-induced pMF is exclusively PKCθ-dependent in normal rats, MEK/ERK is recruited by neuroinflammation to sustain, and even augment downstream plasticity. Because AIH is being developed as a therapeutic modality to restore breathing in people living with multiple neurological disorders, it is important to understand how inflammation, a common comorbidity in many traumatic or degenerative central nervous system disorders, impacts phrenic motor plasticity.NEW & NOTEWORTHY We demonstrate that even mild systemic inflammation shifts signaling mechanisms giving rise to BDNF-induced phrenic motor plasticity. This finding has important experimental, biological, and translational implications, particularly since BDNF-dependent spinal plasticity is being translated to restore breathing and nonrespiratory movements in diverse clinical disorders, such as spinal cord injury (SCI) and amyotrophic lateral sclerosis (ALS).
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Affiliation(s)
- Ibis M Agosto-Marlin
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin, United States
| | - Maria Nikodemova
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, Florida, United States
- Department of Physical, Therapy University of Florida, Gainesville, Florida, United States
- McKnight Brain Institute, University of Florida, Gainesville, Florida, United States
| | - Erica A Dale
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, Florida, United States
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, United States
- McKnight Brain Institute, University of Florida, Gainesville, Florida, United States
| | - Gordon S Mitchell
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin, United States
- Breathing Research and Therapeutics Center, University of Florida, Gainesville, Florida, United States
- Department of Physical, Therapy University of Florida, Gainesville, Florida, United States
- McKnight Brain Institute, University of Florida, Gainesville, Florida, United States
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11
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Vijaya AK, Iešmantaitė M, Mela V, Baltriukienė D, Burokas A. Microglia isolation from aging mice for cell culture: A beginner's guide. Front Cell Neurosci 2023; 17:1082180. [PMID: 36744004 PMCID: PMC9893793 DOI: 10.3389/fncel.2023.1082180] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 01/03/2023] [Indexed: 01/20/2023] Open
Abstract
Microglia, the innate immune cell of the central nervous system, play significant roles in brain development, maintenance, homeostasis, and neuroinflammation. Although numerous methods have been developed to isolate microglia from embryonic or postnatal mouse brains, still major difficulties exist in isolating microglia from adult mice, often resulting in low yield and risk of cellular activation. Therefore, there is a need for a more efficient method to isolate pure and high-yield microglia from adult mice to study various neurodegenerative diseases. The aim of this study was to develop a fully functional protocol for the isolation of microglia by comparing different protocols. We investigated the efficacy of three protocols in terms of cell yield, purity, cellular activation, cellular aging, and migration properties and proposed the modified protocol (PROTOCOL 1), which provides an optimal yield of functional microglial cells with a minimum of material and equipment and allows young researchers with little experience to isolate microglia and helps them to delve deeper into the world of neuroscience.
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Affiliation(s)
- Akshay Kumar Vijaya
- Department of Biological Models, Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Monika Iešmantaitė
- Department of Biological Models, Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Virginia Mela
- Department of Medicine and Dermatology, Faculty of Medicine, University of Malaga, Málaga, Spain
| | - Daiva Baltriukienė
- Department of Biological Models, Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania,*Correspondence: Daiva Baltriukienė,
| | - Aurelijus Burokas
- Department of Biological Models, Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania,Aurelijus Burokas,
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12
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A simplified procedure for isolation of primary murine microglia. Biotechniques 2022; 73:273-279. [DOI: 10.2144/btn-2022-0054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
There are various approaches in which one can isolate microglia from murine brains, such as immunomagnetic, density gradient, FACS and differential adhesive methods. In this procedure a modified flask-tapping approach was used due to its simplicity and reproducibility. Our protocol requires only a single step to isolate the microglia from the mixed cell population. Once the microglia were isolated, we characterized cell purity, microglial morphology and phagocytic activity. The single-step protocol, without the need for additional astrocyte or oligodendrocyte separation, allows microglial cells to be used immediately for experimental purposes. The protocol is low-cost and can be performed in any lab with standard cell-culture equipment.
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13
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Cakir B, Kiral FR, Park IH. Advanced in vitro models: Microglia in action. Neuron 2022; 110:3444-3457. [PMID: 36327894 DOI: 10.1016/j.neuron.2022.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/28/2022] [Accepted: 10/04/2022] [Indexed: 11/05/2022]
Abstract
In the central nervous system (CNS), microglia carry out multiple tasks related to brain development, maintenance of brain homeostasis, and function of the CNS. Recent advanced in vitro model systems allow us to perform more detailed and specific analyses of microglial functions in the CNS. The development of human pluripotent stem cells (hPSCs)-based 2D and 3D cell culture methods, particularly advancements in brain organoid models, offers a better platform to dissect microglial function in various contexts. Despite the improvement of these methods, there are still definite restrictions. Understanding their drawbacks and benefits ensures their proper use. In this primer, we review current developments regarding in vitro microglial production and characterization and their use to address fundamental questions about microglial function in healthy and diseased states, and we discuss potential future improvements with a particular emphasis on brain organoid models.
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Affiliation(s)
- Bilal Cakir
- Department of Genetics, Yale Stem Cell Center, Child Study Center, Yale School of Medicine, New Haven, CT 06520, USA.
| | - Ferdi Ridvan Kiral
- Department of Genetics, Yale Stem Cell Center, Child Study Center, Yale School of Medicine, New Haven, CT 06520, USA
| | - In-Hyun Park
- Department of Genetics, Yale Stem Cell Center, Child Study Center, Yale School of Medicine, New Haven, CT 06520, USA.
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14
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Doughty D, Rajpurohit SK, Trang A, Alptekin A, Korkaya AK, Achyut BR, Arbab AS, Bradford JW. Development of a novel purification protocol to isolate and identify brain microglia. Exp Biol Med (Maywood) 2022; 247:1433-1446. [PMID: 35666093 PMCID: PMC9493764 DOI: 10.1177/15353702221096060] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Microglia, the tissue-resident macrophage of the central nervous system (CNS), play a paramount role in brain health and disease status. Here, we describe a novel method for enriching and isolating primary microglia from mouse brain tissue. This isolation method yields a high number of cells from either young or adult mice, and importantly, maintains the health and function of the cells for subsequent cell culture. We also describe flow cytometry methods using novel cell surface markers, including CX3CR1 and Siglec-H, to specifically label microglia while avoiding other bone marrow and/or non-CNS derived macrophages and monocytes, which has been historically difficult to achieve. As microglia are crucial in multiple aspects of biology, such as in normal brain development/function, immune response, neurodegeneration, and cancer, this isolation technique could greatly benefit a wide range of studies in human CNS biology, health, and disease mechanisms. Being able to isolate a largely pure population of microglia could also allow for a more comprehensive understanding of their functional dynamics and role in disease mechanisms, advancement of potential biomarkers, and development of novel therapeutic targets to improve prognosis and quality of life in multiple diseases.
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Affiliation(s)
- Deanna Doughty
- Department of Biological Sciences,
Augusta University, Augusta, GA 30912, USA,D. D. is Medical College of Georgia,
Augusta University, Augusta, GA 30912, USA
| | | | - Amy Trang
- Department of Biological Sciences,
Augusta University, Augusta, GA 30912, USA
| | - Ahmet Alptekin
- Georgia Cancer Center, Augusta
University, Augusta, GA 30912, USA
| | - Ahmet K Korkaya
- Department of Biological Sciences,
Augusta University, Augusta, GA 30912, USA
| | - Bhagelu R Achyut
- Winship Cancer Institute, Emory
University, Atlanta, GA 30322, USA
| | - Ali S Arbab
- Georgia Cancer Center, Augusta
University, Augusta, GA 30912, USA
| | - Jennifer W Bradford
- Department of Biological Sciences,
Augusta University, Augusta, GA 30912, USA,Jennifer W Bradford.
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15
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Aktories P, Petry P, Kierdorf K. Microglia in a Dish—Which Techniques Are on the Menu for Functional Studies? Front Cell Neurosci 2022; 16:908315. [PMID: 35722614 PMCID: PMC9204042 DOI: 10.3389/fncel.2022.908315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/11/2022] [Indexed: 12/12/2022] Open
Abstract
Microglia build the first line of defense in the central nervous system (CNS) and play central roles during development and homeostasis. Indeed, they serve a plethora of diverse functions in the CNS of which many are not yet fully described and more are still to be discovered. Research of the last decades unraveled an implication of microglia in nearly every neurodegenerative and neuroinflammatory disease, making it even more challenging to elucidate molecular mechanisms behind microglial functions and to modulate aberrant microglial behavior. To understand microglial functions and the underlying signaling machinery, many attempts were made to employ functional in vitro studies of microglia. However, the range of available cell culture models is wide and they come with different advantages and disadvantages for functional assays. Here we aim to provide a condensed summary of common microglia in vitro systems and discuss their potentials and shortcomings for functional studies in vitro.
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Affiliation(s)
- Philipp Aktories
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Philippe Petry
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Katrin Kierdorf
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
- CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- *Correspondence: Katrin Kierdorf
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16
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Ahn JJ, Islam Y, Miller RH. Cell type specific isolation of primary astrocytes and microglia from adult mouse spinal cord. J Neurosci Methods 2022; 375:109599. [PMID: 35460698 DOI: 10.1016/j.jneumeth.2022.109599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/20/2022] [Accepted: 04/11/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Astrocytes and microglia are essential cellular elements of the CNS that are critical for normal development, function, and injury responses. Both cell types are highly pleiotropic and respond rapidly to environmental changes, making them challenging to characterize. One approach is to develop efficient isolation paradigms of distinct cell populations, allowing for characterization of their roles in distinct CNS regions and in pathological states. NEW METHOD We have developed an efficient and reliable protocol for isolation of astrocytes and microglia from the adult mouse spinal cord, which can be easily manipulated for immediate or future analyses. This method involves (1) rapid tissue dissociation; (2) cell release after myelin debris removal; (3) magnetic-activated cell sorting; and (4) optional downstream molecular and functional analyses. RESULTS High levels of viability and purity of the cells were confirmed after isolation. More importantly, characterization of cells verified their ability to proliferate and respond to external stimuli for potential use in downstream molecular and functional assays. COMPARISON WITH EXISTING METHOD(S) Long-term culture of cells isolated from neonatal animals and cell type specific isolation from the brain have been successful; however, isolation of spinal cord cells from adult mice has been challenging due to the large amount of myelin and limited size of the tissue compared to the brain. Our method allows for efficient isolation of astrocytes and microglia from spinal cord alone and includes simple modifications to allow for various downstream applications. CONCLUSIONS This technique will be a valuable tool to better understand the functions of astrocytes and microglia in spinal cord function and pathology.
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Affiliation(s)
- Julie J Ahn
- Department of Anatomy and Cell Biology, George Washington University, 2300 I Street NW, Ross Hall 736, Washington, DC 20037, USA.
| | - Yusra Islam
- Department of Anatomy and Cell Biology, George Washington University, 2300 I Street NW, Ross Hall 736, Washington, DC 20037, USA.
| | - Robert H Miller
- Department of Anatomy and Cell Biology, George Washington University, 2300 I Street NW, Ross Hall 736, Washington, DC 20037, USA.
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17
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Minimizing the Ex Vivo Confounds of Cell-Isolation Techniques on Transcriptomic and Translatomic Profiles of Purified Microglia. eNeuro 2022; 9:ENEURO.0348-21.2022. [PMID: 35228310 PMCID: PMC8970438 DOI: 10.1523/eneuro.0348-21.2022] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 12/10/2021] [Accepted: 01/25/2022] [Indexed: 01/21/2023] Open
Abstract
Modern molecular and biochemical neuroscience studies require analysis of specific cellular populations derived from brain tissue samples to disambiguate cell type-specific events. This is particularly true in the analysis of minority glial populations in the brain, such as microglia, which may be obscured in whole tissue analyses. Microglia have central functions in development, aging, and neurodegeneration and are a current focus of neuroscience research. A long-standing concern for glial biologists using in vivo models is whether cell isolation from CNS tissue could introduce ex vivo artifacts in microglia, which respond quickly to changes in the environment. Mouse microglia were purified by magnetic-activated cell sorting (MACS), as well as cytometer-based and cartridge-based fluorescence-activated cell sorting (FACS) approaches to compare and contrast performance. The Cx3cr1-NuTRAP mouse model was used to provide an endogenous fluorescent microglial marker and a microglial-specific translatome profile as a baseline comparison lacking cell isolation artifacts. All sorting methods performed similarly for microglial purity with main differences being in cell yield and time of isolation. Ex vivo activation signatures occurred principally during the initial tissue dissociation and cell preparation and not the cell sorting. The cell preparation-induced activational phenotype could be minimized by inclusion of transcriptional and translational inhibitors or non-enzymatic dissociation conducted entirely at low temperatures. These data demonstrate that a variety of microglial isolation approaches can be used, depending on experimental needs, and that inhibitor cocktails are effective at reducing cell preparation artifacts.
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18
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Vailati-Riboni M, Rund L, Caetano-Silva ME, Hutchinson NT, Wang SS, Soto-Díaz K, Woods JA, Steelman AJ, Johnson RW. Dietary Fiber as a Counterbalance to Age-Related Microglial Cell Dysfunction. Front Nutr 2022; 9:835824. [PMID: 35360677 PMCID: PMC8964049 DOI: 10.3389/fnut.2022.835824] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 02/22/2022] [Indexed: 12/24/2022] Open
Abstract
With increasing age, microglia shift toward a pro-inflammatory phenotype that may predispose individuals to neurodegenerative disease. Because fiber fermentation in the colon produces bioactive short-chain fatty acids (SCFAs; e.g., acetate, butyrate, and propionate) that signal through the gut-brain axis, increasing dietary fiber may prevent or reverse age-related dysregulation of microglia. Adult (3–4 months old) and aged (23–24 months old) male and female mice were given ad libitum access to a modified AIN-93M diet with 1% cellulose or the same diet with 2.5 or 5.0% inulin for 8 weeks. Several adult and aged male mice fed 0 or 5% inulin were randomly selected for whole brain single-cell RNA sequencing (scRNA-seq) and differential gene expression analysis to classify brain microglia according to gene expression profile; and identify additional genetic markers of aging as possible targets for dietary interventions. Microglia were isolated from remaining mice and expression of selected aging-, inflammatory-, and sensome-related genes was assessed by Fluidigm as was the ex vivo secretion of tumor necrosis factor-alpha (TNF-α). SCFAs were measured in samples collected from the cecum. Microglia from adult and aged mice segregated into distinct phenotypes according to their gene expression profile. In aged mice, a considerably greater proportion of the population of microglia was identified being “activated” and a considerably smaller proportion was identified being “quiescent.” These findings using whole brain scRNA-seq were largely corroborated using highly purified microglia and Fluidigm analysis to assess a selected panel of genes. Aged mice compared to adults had lower levels of SCFA’s in cecum. Dietary inulin increased SCFAs in cecum and mostly restored microglial cell gene expression and TNF-α secretion to that seen in adults. Sex differences were observed with females having lower levels of SCFAs in cecum and increased neuroinflammation. Overall, these data support the use of fiber supplementation as a strategy to counterbalance the age-related microglial dysregulation.
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Affiliation(s)
- Mario Vailati-Riboni
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Laurie Rund
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Maria Elisa Caetano-Silva
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Noah T. Hutchinson
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Selena S. Wang
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Katiria Soto-Díaz
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Jeffrey A. Woods
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Andrew J. Steelman
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Rodney W. Johnson
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- *Correspondence: Rodney W. Johnson,
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19
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Zelenka L, Pägelow D, Krüger C, Seele J, Ebner F, Rausch S, Rohde M, Lehnardt S, van Vorst K, Fulde M. Novel protocol for the isolation of highly purified neonatal murine microglia and astrocytes. J Neurosci Methods 2022; 366:109420. [PMID: 34808220 DOI: 10.1016/j.jneumeth.2021.109420] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/02/2021] [Accepted: 11/11/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND The crosstalk and reactivity of the cell type glia, especially microglia and astrocytes, have progressively gathered research attention in understanding proper brain function regulated by the innate immune response. Therefore, methods to isolate highly viable and pure glia for the analysis on a cell-specific level are indispensable. NEW METHOD We modified previously established techniques: Animal numbers were reduced by multiple microglial harvests from the same mixed glial culture, thereby maximizing microglial yields following the principles of the 3Rs (replacement, reduction, and refinement). We optimized Magnetic-activated cell sorting (MACS®) of microglia and astrocytes by applying cultivated primary glial cell suspensions instead of directly sorting dissociated single cell suspension. RESULTS We generated highly viable and pure microglia and astrocytes derived from a single mixed culture with a purity of ~99%, as confirmed by FACS analysis. Field emission scanning electron microscopy (FESEM) demonstrated integrity of the MACS-purified glial cells. Tumor necrosis factor (TNF) and Interleukin-10 (IL-10) ELISA confirmed pro- and anti-inflammatory responses to be functional in purified glia, but significantly weakened compared to non-purified cells, further highlighting the importance of cellular crosstalk for proper immune activation. COMPARISON WITH EXISTING METHOD(S) Unlike previous studies that either isolated a single type of glia or displayed a substantial proportion of contamination with other cell types, we achieved isolation of both microglia and astrocytes at an increased purity (99-100%). CONCLUSIONS We have created an optimized protocol for the efficient purification of both primary microglia and astrocytes. Our results clearly demonstrate the importance of purity in glial cell cultivation in order to examine immune responses, which particularly holds true for astrocytes. We propose the novel protocol as a tool to investigate the cell type-specific crosstalk between microglia and astrocytes in the frame of CNS diseases.
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Affiliation(s)
- Laura Zelenka
- Institute of Microbiology and Epizootics, Centre of Infection Medicine, Freie Universität Berlin, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany
| | - Dennis Pägelow
- Institute of Microbiology and Epizootics, Centre of Infection Medicine, Freie Universität Berlin, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany
| | - Christina Krüger
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jana Seele
- University Medical Center Göttingen, Institute of Neuropathology, Göttingen, Germany
| | - Friederike Ebner
- Freie Universität Berlin, Institute of Immunology, Berlin, Germany
| | - Sebastian Rausch
- Freie Universität Berlin, Institute of Immunology, Berlin, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Seija Lehnardt
- Institute of Cell Biology and Neurobiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; Department of Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Kira van Vorst
- Institute of Microbiology and Epizootics, Centre of Infection Medicine, Freie Universität Berlin, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany
| | - Marcus Fulde
- Institute of Microbiology and Epizootics, Centre of Infection Medicine, Freie Universität Berlin, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany.
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20
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Yoo HJ, Kwon MS. Aged Microglia in Neurodegenerative Diseases: Microglia Lifespan and Culture Methods. Front Aging Neurosci 2022; 13:766267. [PMID: 35069173 PMCID: PMC8766407 DOI: 10.3389/fnagi.2021.766267] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 12/06/2021] [Indexed: 12/20/2022] Open
Abstract
Microglia have been recognized as macrophages of the central nervous system (CNS) that are regarded as a culprit of neuroinflammation in neurodegenerative diseases. Thus, microglia have been considered as a cell that should be suppressed for maintaining a homeostatic CNS environment. However, microglia ontogeny, fate, heterogeneity, and their function in health and disease have been defined better with advances in single-cell and imaging technologies, and how to maintain homeostatic microglial function has become an emerging issue for targeting neurodegenerative diseases. Microglia are long-lived cells of yolk sac origin and have limited repopulating capacity. So, microglial perturbation in their lifespan is associated with not only neurodevelopmental disorders but also neurodegenerative diseases with aging. Considering that microglia are long-lived cells and may lose their functional capacity as they age, we can expect that aged microglia contribute to various neurodegenerative diseases. Thus, understanding microglial development and aging may represent an opportunity for clarifying CNS disease mechanisms and developing novel therapies.
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Affiliation(s)
- Hyun-Jung Yoo
- Department of Pharmacology, School of Medicine, Research Institute for Basic Medical Science, CHA University, Cha Bio Complex, Seongnam-si, South Korea
- Research Competency Milestones Program (RECOMP) of School of Medicine, CHA University, Seongnam-si, South Korea
| | - Min-Soo Kwon
- Department of Pharmacology, School of Medicine, Research Institute for Basic Medical Science, CHA University, Cha Bio Complex, Seongnam-si, South Korea
- *Correspondence: Min-Soo Kwon,
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21
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Method of Microglial DNA-RNA Purification from a Single Brain of an Adult Mouse. Methods Protoc 2021; 4:mps4040086. [PMID: 34940397 PMCID: PMC8704779 DOI: 10.3390/mps4040086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/24/2021] [Accepted: 11/25/2021] [Indexed: 11/17/2022] Open
Abstract
Microglia, the resident brain immune effectors cells, show dynamic activation level changes for most neuropsychiatric diseases, reflecting their complex regulatory function and potential as a therapeutic target. Emerging single-cell molecular biology studies are used to investigate the genetic modification of individual cells to better understand complex gene regulatory pathways. Although multiple protocols for microglia isolation from adult mice are available, it is always challenging to get sufficient purified microglia from a single brain for simultaneous DNA and RNA extraction for subsequent downstream analysis. Moreover, for data comparison between treated and untreated groups, standardized cell isolation techniques are essential to decrease variability. Here, we present a combined method of microglia isolation from a single adult mouse brain, using a magnetic bead-based column separation technique, and a column-based extraction of purified DNA-RNA from the isolated microglia for downstream application. Our current method provides step-by-step instructions accompanied by visual explanations of important steps for isolating DNA-RNA simultaneously from a highly purified microglia population.
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22
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Liu P, Qin D, Lv H, Fan W, Zhou F, Gao Z, Tao Z, Xu Y. Activation of Dopamine D2 Receptor Alleviates Neuroinflammation in a Mouse Model of Allergic Rhinitis With Olfactory Dysfunction. ALLERGY, ASTHMA & IMMUNOLOGY RESEARCH 2021; 13:882-895. [PMID: 34734506 PMCID: PMC8569020 DOI: 10.4168/aair.2021.13.6.882] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/03/2021] [Accepted: 04/21/2021] [Indexed: 12/13/2022]
Abstract
Purpose Allergic rhinitis (AR) is a common otolaryngology disease and one of the clinical causes of olfactory dysfunction (OD). The olfactory bulb serves as a transfer station for olfactory information transmission, and alleviating its neuroinflammation may be expected to improve AR-induced OD. Recent studies have suggested that the dopamine D2 receptor acts as a key target in regulating immune functions and neuroinflammatory reaction. However, the effect of dopamine D2 receptor on AR-induced neuroinflammation is still unknown. Methods An AR mouse model with OD induced by ovalbumin were constructed. The buried food pellet test was to evaluate the olfactory function of the mice. Immunofluorescence staining, hematoxylin and eosin staining, enzyme-linked immunosorbent assay and western blotting were also used to investigate the molecular mechanisms underlying the anti-inflammatory effects of the dopamine D2 receptor in AR-induced OD. Results We found that AR-induced OD has a relationship with inflammatory responses in the olfactory bulb. Nasal administration of quinpirole (Quin, a dopamine D2 receptor agonist, 3 mg/kg) improved olfactory function in mice, inhibited the expression of toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signalings and the levels of tumor necrosis factor-α, interleukin (IL)-1β and IL-6 in the olfactory bulb. In vitro, Quin (20 μmol/L) inhibited the release of TLR4/NF-κB signalings-dependent inflammatory cytokines in cultured microglia. Conclusions Activation of the dopamine D2 receptor inhibits the release of inflammatory cytokines through TLR4/NF-κB signaling in the olfactory bulb microglia, and protects olfactory function.
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Affiliation(s)
- Peiqiang Liu
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China.,Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Danxue Qin
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China.,Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Hao Lv
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China.,Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Wenjun Fan
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China.,Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Fangwei Zhou
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China.,Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Ziang Gao
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China.,Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zezhang Tao
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China.,Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yu Xu
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China.,Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China.
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23
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Caetano-Silva ME, Rund LA, Vailati-Riboni M, Pacheco MTB, Johnson RW. Copper-Binding Peptides Attenuate Microglia Inflammation through Suppression of NF-kB Pathway. Mol Nutr Food Res 2021; 65:e2100153. [PMID: 34532985 PMCID: PMC8612997 DOI: 10.1002/mnfr.202100153] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 08/12/2021] [Indexed: 11/07/2022]
Abstract
SCOPE Activation of microglia, the resident immune cells of the central nervous system, has been related to the etiology and progression of neurodegenerative diseases; thus, finding novel approaches to suppress the neuroinflammatory process is of utmost relevance. METHODS AND RESULTS The anti-inflammatory activity of whey Cu-, Fe-, and Zn-binding peptides and their possible underlying mechanism of action were evaluated in microglia. Whey metal-binding peptides decreased nitric oxide production and tumor necrosis factor α (TNF-α) at mRNA and protein levels by stimulated BV-2 microglia in comparison to the control with no peptide treatment. The hydrophobicity, specific sequences, and possible synergistic effects seem to play a role. Cu-binding peptides (Cu-bp) presented anti-inflammatory activity both in BV-2 and primary microglia cultures. These peptides exert their action by suppressing nuclear factor kappa B (NF-kB) pathway since nuclear translocation of NF-kB p65 is decreased by roughly 30% upon Cu-bp treatment. Specific sequences identified in Cu-bp showed high affinity to bind NF-kB p65 by molecular docking (up to -8.8 kcal mol-1 ), corroborating the immunofluorescence studies. CONCLUSION Cu-bp represent food-derived peptides that may be useful for neuroprotective purposes. Chelation of copper excess in the CNS and the bioavailability of such peptides, as well as their behavior in in vivo models, deserve further research for future applications.
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Affiliation(s)
- Maria Elisa Caetano-Silva
- Center of Food Science and Quality (CCQA), Institute of Food Technology (Ital), Campinas, SP 13070-178, Brazil
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Laurie A. Rund
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Mario Vailati-Riboni
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | | | - Rodney W. Johnson
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
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24
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Liu P, Qin D, Lv H, Fan W, Tao Z, Xu Y. Neuroprotective effects of dopamine D2 receptor agonist on neuroinflammatory injury in olfactory bulb neurons in vitro and in vivo in a mouse model of allergic rhinitis. Neurotoxicology 2021; 87:174-181. [PMID: 34624383 DOI: 10.1016/j.neuro.2021.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/22/2021] [Accepted: 10/01/2021] [Indexed: 11/17/2022]
Abstract
Available evidence indicates that dopamine D2 receptor modulates the neurotoxic effects induced by glutamate. However, neurotoxicity mediated by AMPA-subtype glutamate receptor has rarely been studied in the olfactory bulb. This study mainly explores the neuroprotective effects of dopamine D2 receptor agonist on AMPA receptor-mediated neurotoxicity in the olfactory bulb in a mouse model of allergic rhinitis (AR) with olfactory dysfunction (OD). In our study, we found that AR with OD was closely associated with increased surface expression of the AMPA receptor GluR1, reduced surface expression of GluR2, and apoptosis damage in the olfactory bulb in vivo. Quinpirole (a dopamine D2 receptor agonist) improved olfactory function in mice, ameliorated apoptosis injury in the olfactory bulb but not in the olfactory mucosa, and inhibited the internalization of GluR2-containing AMPA receptor in vitro and in vivo. In addition, phosphorylation plays a crucial role in the regulation of AMPA receptor trafficking. Our results showed that quinpirole reduced the phosphorylation of GluR1 S845 and GluR2 S880 in olfactory bulb neurons in vitro, but it had no obvious effect on GluR1 S831. Therefore, dopamine D2 receptor agonist may inhibit the phosphorylation of GluR1 S845 and GluR2 S880, thereby reducing AMPA receptor-mediated neurotoxicity and alleviating neurotoxic injury to the olfactory bulb caused by AR.
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Affiliation(s)
- Peiqiang Liu
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China; Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Danxue Qin
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China; Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Hao Lv
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China; Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Wenjun Fan
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China; Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zezhang Tao
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China; Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yu Xu
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China; Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China.
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25
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Zhong H, Yu H, Sun J, Chen J, Huang S, Huang P, Liu X, Zhong Y. Isolation of microglia from retinas of chronic ocular hypertensive rats. Open Life Sci 2021; 16:992-1001. [PMID: 34604533 PMCID: PMC8445004 DOI: 10.1515/biol-2021-0100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 08/13/2021] [Accepted: 08/13/2021] [Indexed: 11/17/2022] Open
Abstract
Microglia are the principal glial cells involved in the processes of immune inflammation within both retina and optic nerve, especially under the context of glaucomatous neuropathy. Considering the distinguishing role of retinal microglia in glaucoma and the lack of established protocol for microglia isolation from animal glaucoma model, the present study aimed to develop and validate a method with characteristics of both simplicity and efficiency for retinal microglia isolation from chronic ocular hypertensive (COH) rats. A Percoll gradient of various concentrations was used to separate microglia from whole retinal cells of the COH rats and control group. The finally isolated microglia were identified by CD11b and Iba-1 immunofluorescence staining, and the cell viability was determined by trypan blue staining. Additionally, the proportion of microglia in the whole retina cells was identified by flow cytometry. Results showed that the survival rates of isolated retinal microglia with the Percoll gradient method were 67.2 ± 4% and 67.6 ± 3% in control and COH groups, respectively. The proportion of the microglia population in the whole retinal cells was about 0.4–0.93%. To conclude, the present study confirmed that the application of Percoll gradient could effectively separate microglia from retinas of COH rats, which will probably enrich the tool kit for basic researchers of glaucoma specialty and help with scientific investigations.
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Affiliation(s)
- Huimin Zhong
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, 200025, Shanghai, China.,Department of Ophthalmology, Shanghai General Hospital (Shanghai First People s Hospital), National Clinical Research Center for Eye Diseases, Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Huan Yu
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, 200025, Shanghai, China
| | - Jun Sun
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, 200025, Shanghai, China
| | - Junjue Chen
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, 200025, Shanghai, China
| | - Shouyue Huang
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, 200025, Shanghai, China
| | - Ping Huang
- Department of Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai 200025, People's Republic of China
| | - Xiaohong Liu
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, 200025, Shanghai, China
| | - Yisheng Zhong
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, 197 Ruijin Er Road, 200025, Shanghai, China
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26
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Xia P, Logiacco F, Huang Y, Kettenmann H, Semtner M. Histamine triggers microglial responses indirectly via astrocytes and purinergic signaling. Glia 2021; 69:2291-2304. [PMID: 34080730 DOI: 10.1002/glia.24039] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/17/2021] [Accepted: 05/19/2021] [Indexed: 02/06/2023]
Abstract
Histamine is a monoaminergic neurotransmitter which is released within the entire brain from ascending axons originating in the tuberomammillary nucleus in a sleep state-dependent fashion. Besides the modulation of neuronal firing patterns, brain histamine levels are also thought to modulate functions of glial cells. Microglia are the innate immune cells and professional phagocytes of the central nervous system, and histamine was previously shown to have multiple effects on microglial functions in health and disease. Isolated microglia respond only to agonists of the Hrh2 subtype of histamine receptors (Hrh), and the expression of that isoform is confirmed by a metadata analysis of microglia transcriptomes. When we studied the effect of the histamine receptor isoforms in cortical and thalamic microglia by in situ live cell Ca2+ imaging using a novel, microglia-specific indicator mouse line, microglial cells respond to external histamine application mainly in a Hrh1-, and to a lower extent also in a Hrh2-dependent manner. The Hrh1 response was sensitive to blockers of purinergic P2ry12 receptors, and since Hrh1 expression was predominantly found in astrocytes, we suggest that the Hrh1 response in microglia is mediated by astrocyte ATP release and activation of P2ry12 receptors in microglia. Histamine also stimulates microglial phagocytic activity via Hrh1- and P2ry12-mediated signaling. Taken together, we provide evidence that histamine acts indirectly on microglial Ca2+ levels and phagocytic activity via astrocyte histamine receptor-controlled purinergic signaling.
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Affiliation(s)
- Pengfei Xia
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Charité-Universitätsmedizin, Berlin, Germany
| | - Francesca Logiacco
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Yimin Huang
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Charité-Universitätsmedizin, Berlin, Germany
| | - Helmut Kettenmann
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Marcus Semtner
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
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27
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Hernández J, Francos-Quijorna I, Redondo-Castro E, López-Vales R, Navarro X. Microglia Stimulation by Protein Extract of Injured Rat Spinal Cord. A Novel In vitro Model for Studying Activated Microglia. Front Mol Neurosci 2021; 14:582497. [PMID: 34093123 PMCID: PMC8176957 DOI: 10.3389/fnmol.2021.582497] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 04/14/2021] [Indexed: 01/07/2023] Open
Abstract
Research on microglia has established the differentiation between the so-called M1 and M2 phenotypes. However, new frameworks have been proposed attempting to discern between meaningful microglia profiles. We have set up an in vitro microglial activation model by adding an injured spinal cord (SCI) lysate to microglial cultures, obtained from postnatal rats, in order to mimic the environment of the spinal cord after injury. We found that under the presence of the SCI lysate microglial cells changed their phenotype, developing less ramified but longer processes, and proliferated. The SCI lysate also led to upregulation of pro-inflammatory cytokines, such as IL-1β, IL-6, and TNF-α, downregulation of the anti-inflammatory cytokines IL-10 and IL-4, and a biphasic profile of iNOS. In addition, a latex beads phagocytosis assay revealed the SCI lysate stimulated the phagocytic capacity of microglia. Flow cytometry analysis indicated that microglial cells showed a pro-inflammatory profile in the presence of SCI lysate. Finally, characterization of the microglial activation in the spinal cord on day 7 after contusion injury, we showed that these cells have a pro-inflammatory phenotype. Overall, these results indicate that the use of SCI lysates could be a useful tool to skew microglia towards a closer phenotype to that observed after the spinal cord contusion injury than the use of LPS or IFNγ.
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Affiliation(s)
- Joaquim Hernández
- Group of Neuroplasticity and Regeneration, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Red de Terapia Celular (TerCel), Bellaterra, Spain
| | - Isaac Francos-Quijorna
- Group of Neuroplasticity and Regeneration, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Red de Terapia Celular (TerCel), Bellaterra, Spain
| | - Elena Redondo-Castro
- Group of Neuroplasticity and Regeneration, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Red de Terapia Celular (TerCel), Bellaterra, Spain
| | - Rubén López-Vales
- Group of Neuroplasticity and Regeneration, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Red de Terapia Celular (TerCel), Bellaterra, Spain
| | - Xavier Navarro
- Group of Neuroplasticity and Regeneration, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Red de Terapia Celular (TerCel), Bellaterra, Spain
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28
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Iron activates microglia and directly stimulates indoleamine-2,3-dioxygenase activity in the N171-82Q mouse model of Huntington's disease. PLoS One 2021; 16:e0250606. [PMID: 33989290 PMCID: PMC8121302 DOI: 10.1371/journal.pone.0250606] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/10/2021] [Indexed: 01/05/2023] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by a dominant CAG-repeat expansion in the huntingtin gene. Microglial activation is a key feature of HD pathology, and is present before clinical disease onset. The kynurenine pathway (KP) of tryptophan degradation is activated in HD, and is thought to contribute to disease progression. Indoleamine-2,3-dioxygenase (IDO) catalyzes the first step in this pathway; this and other pathway enzymes reside with microglia. While HD brain microglia accumulate iron, the role of iron in promoting microglial activation and KP activity is unclear. Here we utilized the neonatal iron supplementation model to investigate the relationship between iron, microglial activation and neurodegeneration in adult HD mice. We show in the N171-82Q mouse model of HD microglial morphologic changes consistent with immune activation. Neonatal iron supplementation in these mice promoted neurodegeneration and resulted in additional microglial activation in adults as determined by increased soma volume and decreased process length. We further demonstrate that iron activates IDO, both in brain lysates and purified recombinant protein (EC50 = 1.24 nM). Brain IDO activity is increased by HD. Neonatal iron supplementation further promoted IDO activity in cerebral cortex, altered KP metabolite profiles, and promoted HD neurodegeneration as measured by brain weights and striatal volumes. Our results demonstrate that dietary iron is an important activator of microglia and the KP pathway in this HD model, and that this occurs in part through a direct effect on IDO. The findings are relevant to understanding how iron promotes neurodegeneration in HD.
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29
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Morini R, Bizzotto M, Perrucci F, Filipello F, Matteoli M. Strategies and Tools for Studying Microglial-Mediated Synapse Elimination and Refinement. Front Immunol 2021; 12:640937. [PMID: 33708226 PMCID: PMC7940197 DOI: 10.3389/fimmu.2021.640937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 02/01/2021] [Indexed: 01/14/2023] Open
Abstract
The role of microglia in controlling synapse homeostasis is becoming increasingly recognized by the scientific community. In particular, the microglia-mediated elimination of supernumerary synapses during development lays the basis for the correct formation of neuronal circuits in adulthood, while the possible reactivation of this process in pathological conditions, such as schizophrenia or Alzheimer's Disease, provides a promising target for future therapeutic strategies. The methodological approaches to investigate microglial synaptic engulfment include different in vitro and in vivo settings. Basic in vitro assays, employing isolated microglia and microbeads, apoptotic membranes, liposomes or synaptosomes allow the quantification of the microglia phagocytic abilities, while co-cultures of microglia and neurons, deriving from either WT or genetically modified mice models, provide a relatively manageable setting to investigate the involvement of specific molecular pathways. Further detailed analysis in mice brain is then mandatory to validate the in vitro assays as representative for the in vivo situation. The present review aims to dissect the main technical approaches to investigate microglia-mediated phagocytosis of neuronal and synaptic substrates in critical developmental time windows.
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Affiliation(s)
- Raffaella Morini
- Laboratory of Pharmacology and Brain Pathology, Neurocenter, Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy
| | - Matteo Bizzotto
- Laboratory of Pharmacology and Brain Pathology, Neurocenter, Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy.,Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy
| | - Fabio Perrucci
- Laboratory of Pharmacology and Brain Pathology, Neurocenter, Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy.,Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy
| | - Fabia Filipello
- Laboratory of Pharmacology and Brain Pathology, Neurocenter, Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy.,Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy.,Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, United States
| | - Michela Matteoli
- Laboratory of Pharmacology and Brain Pathology, Neurocenter, Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy.,Consiglio Nazionale Delle Ricerche (CNR), Institute of Neuroscience - URT Humanitas, Rozzano, Italy
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30
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Hsu NJ, Jacobs M. The Use of Murine Infection Models to Investigate the Protective Role of TNF in Central Nervous System Tuberculosis. Methods Mol Biol 2021; 2248:211-220. [PMID: 33185878 DOI: 10.1007/978-1-0716-1130-2_15] [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] [Indexed: 06/11/2023]
Abstract
Tuberculosis of the central nervous system (CNS-TB) is the most severe form of extra-pulmonary tuberculosis that is often associated with high mortality. Secretion of tumor necrosis factor (TNF) has important protective and immune modulatory functions for immune responses during CNS-TB. Therefore, by combining the approaches of aerosol and intracerebral infection in mice, this chapter describes the methods to investigate the contribution of TNF in protective immunity against CNS-TB infection.
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Affiliation(s)
- Nai-Jen Hsu
- Division of Immunology, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Muazzam Jacobs
- Division of Immunology, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
- National Health Laboratory Service, Johannesburg, South Africa.
- Immunology of Infectious Disease Research Unit, University of Cape Town, Cape Town, South Africa.
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31
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Bruzelius A, Hidalgo I, Boza-Serrano A, Hjelmér AG, Tison A, Deierborg T, Bengzon J, Ramos-Moreno T. The human bone marrow harbors a CD45 - CD11B + cell progenitor permitting rapid microglia-like cell derivative approaches. Stem Cells Transl Med 2020; 10:582-597. [PMID: 33295698 PMCID: PMC7980218 DOI: 10.1002/sctm.20-0127] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 09/23/2020] [Accepted: 10/25/2020] [Indexed: 12/21/2022] Open
Abstract
Microglia, the immune sentinel of the central nervous system (CNS), are generated from yolk sac erythromyeloid progenitors that populate the developing CNS. Interestingly, a specific type of bone marrow-derived monocyte is able to express a yolk sac microglial signature and populate CNS in disease. Here we have examined human bone marrow (hBM) in an attempt to identify novel cell sources for generating microglia-like cells to use in cell-based therapies and in vitro modeling. We demonstrate that hBM stroma harbors a progenitor cell that we name stromal microglial progenitor (STR-MP). STR-MP single-cell gene analysis revealed the expression of the consensus genetic microglial signature and microglial-specific genes present in development and CNS pathologies. STR-MPs can be expanded and generate microglia-like cells in vitro, which we name stromal microglia (STR-M). STR-M cells show phagocytic ability, classically activate, and survive and phagocyte in human brain tissue. Thus, our results reveal that hBM harbors a source of microglia-like precursors that can be used in patient-centered fast derivative approaches.
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Affiliation(s)
- Andreas Bruzelius
- Division of Neurosurgery, Department of Clinical Sciences Lund, Skåne University Hospital, Lund Stem Cell Center, Lund, Sweden.,Department of Experimental Medical Science and Lund Stem Cell Center BMC, Lund University, Lund, Sweden
| | - Isabel Hidalgo
- Division of Neurosurgery, Department of Clinical Sciences Lund, Skåne University Hospital, Lund Stem Cell Center, Lund, Sweden.,Institution for Laboratory Medicine, Division of Molecular Hematology, Faculty of Medicine, Lund University, Lund, Sweden
| | - Antonio Boza-Serrano
- Departamento de Bioquimica y Biologia Molecular, Facultad de Farmacia e Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocio/CSIC/Universidad de Sevilla, Seville, Spain.,Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Bio Medical Center (BMC)., Lund University, Lund, Sweden
| | - Anna-Giorgia Hjelmér
- Division of Neurosurgery, Department of Clinical Sciences Lund, Skåne University Hospital, Lund Stem Cell Center, Lund, Sweden
| | - Amelie Tison
- Division of Neurosurgery, Department of Clinical Sciences Lund, Skåne University Hospital, Lund Stem Cell Center, Lund, Sweden
| | - Tomas Deierborg
- Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Bio Medical Center (BMC)., Lund University, Lund, Sweden
| | - Johan Bengzon
- Division of Neurosurgery, Department of Clinical Sciences Lund, Skåne University Hospital, Lund Stem Cell Center, Lund, Sweden
| | - Tania Ramos-Moreno
- Division of Neurosurgery, Department of Clinical Sciences Lund, Skåne University Hospital, Lund Stem Cell Center, Lund, Sweden.,Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Bio Medical Center (BMC)., Lund University, Lund, Sweden
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32
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Lei X, Chen X, Quan Y, Tao Y, Li J. Targeting CYP2J2 to Enhance the Anti-Glioma Efficacy of Cannabinoid Receptor 2 Stimulation by Inhibiting the Pro-Angiogenesis Function of M2 Microglia. Front Oncol 2020; 10:574277. [PMID: 33330047 PMCID: PMC7729163 DOI: 10.3389/fonc.2020.574277] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/28/2020] [Indexed: 12/14/2022] Open
Abstract
Enhancing the therapeutic efficacy of anti-tumor drugs is essential for cancer management. Although cannabinoid receptor 2 (CB2R) stimulation exerts anti-tumor action in glioma cells by regulating cellular proliferation, differentiation, or apoptosis, selective CB2R agonist alone does not achieve a satisfactory therapeutic outcome. Herein, we aimed to evaluate the possible strategy for enhancing the anti-glioma efficacy of JWH133, a selective CB2R agonist. In this study, immunofluorescence and qRT-PCR were used to investigate microglia polarization. Tumor growth was monitored via bioluminescent imaging using the IVIS Spectrum System. The angiogenesis of human brain microvascular endothelial cells (HBMECs) was detected by the tube formation assay. qRT-PCR was used to investigate cytochrome P450 2J2 (CYP2J2) and 11,12-epoxyeicosatrienoic acid (11,12-EET) expression. Our results showed that administration of JWH133 significantly promoted microglial M2 polarization both in vitro and in vivo. The medium supernatant of M2 microglia induced by JWH133 treatment facilitated angiogenesis of HBMECs. CYP2J2 expression and 11,12-EET release in the supernatant of JWH133-induced M2 microglia were significantly upregulated. Treatment with 11,12-EET prompted HBMEC angiogenesis and glioma growth. CYP2J2 knockdown restrained the release of 11,12-EET and significantly enhanced the anti-tumor effect of JWH133 on glioma. This study showed that targeting CYP2J2 might be a beneficial strategy to enhance the anti-glioma efficacy of JWH133 by inhibiting the pro-angiogenesis function of M2 microglia.
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Affiliation(s)
- Xuejiao Lei
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Xuezhu Chen
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Yulian Quan
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Yihao Tao
- Department of Neurosurgery, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Junlong Li
- Office of Scientific Research Administration, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
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33
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Butler MJ, Cole RM, Deems NP, Belury MA, Barrientos RM. Fatty food, fatty acids, and microglial priming in the adult and aged hippocampus and amygdala. Brain Behav Immun 2020; 89:145-158. [PMID: 32544595 PMCID: PMC7572563 DOI: 10.1016/j.bbi.2020.06.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 05/20/2020] [Accepted: 06/06/2020] [Indexed: 02/08/2023] Open
Abstract
Short-term (3-day) consumption of a high fat diet (HFD) rich in saturated fats is associated with a neuroinflammatory response and subsequent cognitive impairment in aged, but not young adult, male rats. This exaggerated effect in aged rats could be due to a "primed" microglial phenotype observed in the normal aging process in rodents in which aged microglia display a potentiated response to immune challenge. Here, we investigated the impact of HFD on microglial priming and lipid composition in the hippocampus and amygdala of young and aged rats. Furthermore, we investigated the microglial response to palmitate, the main saturated fatty acid (SFA) found in HFD that is proinflammatory. Our results indicate that HFD increased gene expression of microglial markers of activation indicative of microglial priming, including CD11b, MHCII, CX3CR1, and NLRP3, as well as the pro-inflammatory marker IL-1β in both hippocampus and amygdala-derived microglia. Furthermore, HFD increased the concentration of SFAs and decreased the concentration of polyunsaturated fatty acids (PUFAs) in the hippocampus. We also observed a specific decrease in the anti-inflammatory PUFA docosahexaenoic acid (DHA) in the hippocampus and amygdala of aged rats. In a separate cohort of young and aged animals, isolated microglia from the hippocampus and amygdala exposed to palmitate in vitro induced an inflammatory gene expression profile mimicking the effects of HFD in vivo. These data suggest that palmitate may be a critical nutritional signal from the HFD that is directly involved in hippocampal and amygdalar inflammation. Interestingly, microglial activation markers were increased in response to HFD or palmitate in an age-independent manner, suggesting that HFD sensitivity of microglia, under these experimental conditions, is not the sole mediator of the exaggerated inflammatory response observed in whole tissue extracts from aged HFD-fed rats.
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Affiliation(s)
- Michael J. Butler
- Institute for Behavioral Medicine Research, Ohio State University, Columbus, OH, USA
| | - Rachel M. Cole
- Department of Human Sciences, Ohio State University, Columbus, OH, USA
| | - Nicholas P. Deems
- Institute for Behavioral Medicine Research, Ohio State University, Columbus, OH, USA
| | - Martha A. Belury
- Institute for Behavioral Medicine Research, Ohio State University, Columbus, OH, USA,Department of Human Sciences, Ohio State University, Columbus, OH, USA
| | - Ruth M. Barrientos
- Institute for Behavioral Medicine Research, Ohio State University, Columbus, OH, USA,Department of Psychiatry and Behavioral Health, Ohio State University, Columbus, OH, USA,Department of Neuroscience, The Ohio State University, Columbus, OH, USA,Chronic Brain Injury Program, Discovery Themes Initiative, The Ohio State University, Columbus, OH, USA,Corresponding author: Dr. Ruth M. Barrientos, Institute for Behavioral Medicine Research and Department of Psychiatry and Behavioral Health, Ohio State University, 460 Medical Center Drive, Columbus, OH 43210, Tel.: 614-293-6591,
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Shu B, He SQ, Guan Y. Spinal Cord Stimulation Enhances Microglial Activation in the Spinal Cord of Nerve-Injured Rats. Neurosci Bull 2020; 36:1441-1453. [PMID: 32889636 DOI: 10.1007/s12264-020-00568-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/23/2020] [Indexed: 12/14/2022] Open
Abstract
Microglia can modulate spinal nociceptive transmission. Yet, their role in spinal cord stimulation (SCS)-induced pain inhibition is unclear. Here, we examined how SCS affects microglial activation in the lumbar cord of rats with chronic constriction injury (CCI) of the sciatic nerve. Male rats received conventional SCS (50 Hz, 80% motor threshold, 180 min, 2 sessions/day) or sham stimulation on days 18-20 post-CCI. SCS transiently attenuated the mechanical hypersensitivity in the ipsilateral hind paw and increased OX-42 immunoreactivity in the bilateral dorsal horns. SCS also upregulated the mRNAs of M1-like markers, but not M2-like markers. Inducible NOS protein expression was increased, but brain-derived neurotrophic factor was decreased after SCS. Intrathecal minocycline (1 μg-100 μg), which inhibits microglial activation, dose-dependently attenuated the mechanical hypersensitivity. Pretreatment with low-dose minocycline (1 μg, 30 min) prolonged the SCS-induced pain inhibition. These findings suggest that conventional SCS may paradoxically increase spinal M1-like microglial activity and thereby compromise its own ability to inhibit pain.
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Affiliation(s)
- Bin Shu
- Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.,Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Shao-Qiu He
- Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA. .,Department of Neurological Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.
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Min Y, Yan L, Wang Q, Wang F, Hua H, Yuan Y, Jin H, Zhang M, Zhao Y, Yang J, Jiang X, Yang Y, Li F. Distinct Residential and Infiltrated Macrophage Populations and Their Phagocytic Function in Mild and Severe Neonatal Hypoxic-Ischemic Brain Damage. Front Cell Neurosci 2020; 14:244. [PMID: 32903800 PMCID: PMC7438904 DOI: 10.3389/fncel.2020.00244] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/15/2020] [Indexed: 01/10/2023] Open
Abstract
Neonatal brain injury, especially severe injury induced by hypoxia-ischemia (HI), causes mortality and long-term neurological impairments. Our previous study demonstrated activation of CD11b+ myeloid cells, including residential microglial cells (MGs) and infiltrating monocyte-derived macrophages (MDMs) in a murine model of hypoxic-ischemic brain damage (HIBD), with unknown functions. Here, we study the differences in the phagocytic function of MGs and MDMs to clarify their potential roles after HIBD. HI was induced in 9-10-day postnatal mice. On days 1 and 3 after injury, pathological and neurobehavioral tests were performed to categorize the brain damage as mild or severe. Flow cytometry was applied to quantify the dynamic change in the numbers of MGs and MDMs according to the relative expression level of CD45 in CD11b+ cells. CX3CR1 GFPCCR2 RFP double-transformed mice were used to identify MGs and MDMs in the brain parenchyma after HIBD. Lysosome-associated membrane protein 1 (LAMP1), toll-like receptor 2 (TLR2), CD36, and transforming growth factor (TGF-β) expression levels were measured to assess the underlying function of phagocytes and neuroprotective factors in these cells. The FITC-dextran 40 phagocytosis assay was applied to examine the change in phagocytic function under oxygen-glucose deprivation (OGD) in vitro. We found that neonatal HI induced a different degree of brain damage: mild or severe injury. Compared with mildly injured animals, mice with severe injury had lower weight, worse neurobehavioral scores, and abnormal brain morphology. In a severely injured brain, CD11b+ cells remarkably increased, including an increase in the MDM population and a decrease in the MG population. Furthermore, MDM infiltration into the brain parenchyma was evident in CX3CR1 GFPCCR2 RFP double-transformed mice. Mild and severe brain injury caused different phagocytosis-related responses and neuroprotective functions of MDMs and MGs at 1 and 3 days following HI. The phagocytic function was activated in BV2 cells but downregulated in Raw264.7 cells under OGD in vitro. These observations indicate that neonatal HI induced different degrees of brain injury. The proportion of infiltrated macrophage MDMs was increased and they were recruited into the injured brain parenchyma in severe brain injury. The resident macrophage MGs proportion decreased and maintained activated phagocytic function in both mild and severe brain injury, and restored neuroprotective function in severe brain injury.
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Affiliation(s)
- Yingjun Min
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Kunming Medical University, Kunming, China
| | - Lin Yan
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Kunming Medical University, Kunming, China
| | - Qian Wang
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Kunming Medical University, Kunming, China
| | - Fang Wang
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Kunming Medical University, Kunming, China
| | - Hairong Hua
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Kunming Medical University, Kunming, China
| | - Yun Yuan
- Department of Human Anatomy and Histoembryology, School of Basic Medical Sciences, Kunming Medical University, Kunming, China
| | - Huiyan Jin
- Department of Functional Experiment, School of Basic Medical Sciences, Kunming Medical University, Kunming, China
| | - Ming Zhang
- Yunnan Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Molecular and Clinical Medicine, Kunming Medical University, Kunming, China
| | - Yaling Zhao
- Department of Obstetrics and Gynecology, First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Jianzhong Yang
- Department of Psychiatry, The Second Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Xiangning Jiang
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
| | - Yuan Yang
- Department of Physiology, School of Basic Medical Sciences, Kunming Medical University, Kunming, China
| | - Fan Li
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Kunming Medical University, Kunming, China
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Ewald AC, Kiernan EA, Roopra AS, Radcliff AB, Timko RR, Baker TL, Watters JJ. Sex- and Region-Specific Differences in the Transcriptomes of Rat Microglia from the Brainstem and Cervical Spinal Cord. J Pharmacol Exp Ther 2020; 375:210-222. [PMID: 32661056 DOI: 10.1124/jpet.120.266171] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 07/07/2020] [Indexed: 12/11/2022] Open
Abstract
The neural control system underlying breathing is sexually dimorphic with males being more vulnerable to dysfunction. Microglia also display sex differences, and their role in the architecture of brainstem respiratory rhythm circuitry and modulation of cervical spinal cord respiratory plasticity is becoming better appreciated. To further understand the molecular underpinnings of these sex differences, we performed RNA sequencing of immunomagnetically isolated microglia from brainstem and cervical spinal cord of adult male and female rats. We used various bioinformatics tools (Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, Reactome, STRING, MAGICTRICKS) to functionally categorize identified gene sets, as well as to pinpoint common transcriptional gene drivers that may be responsible for the observed transcriptomic differences. We found few sex differences in the microglial transcriptomes derived from the brainstem, but several hundred genes were differentially expressed by sex in cervical spinal microglia. Comparing brainstem and spinal microglia within and between sexes, we found that the major factor guiding transcriptomic differences was central nervous system (CNS) location rather than sex. We further identified key transcriptional drivers that may be responsible for the transcriptomic differences observed between sexes and CNS regions; enhancer of zeste homolog 2 emerged as the predominant driver of the differentially downregulated genes. We suggest that functional gene alterations identified in metabolism, transcription, and intercellular communication underlie critical microglial heterogeneity and sex differences in CNS regions that contribute to respiratory disorders categorized by dysfunction in neural control. These data will also serve as an important resource data base to advance our understanding of innate immune cell contributions to sex differences and the field of respiratory neural control. SIGNIFICANCE STATEMENT: The contributions of central nervous system (CNS) innate immune cells to sexually dimorphic differences in the neural circuitry controlling breathing are poorly understood. We identify key transcriptomic differences, and their transcriptional drivers, in microglia derived from the brainstem and the C3-C6 cervical spinal cord of healthy adult male and female rats. Gene alterations identified in metabolism, gene transcription, and intercellular communication likely underlie critical microglial heterogeneity and sex differences in these key CNS regions that contribute to the neural control of breathing.
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Affiliation(s)
- Andrea C Ewald
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Elizabeth A Kiernan
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Avtar S Roopra
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Abigail B Radcliff
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Rebecca R Timko
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Tracy L Baker
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Jyoti J Watters
- Departments of Comparative Biosciences (A.C.E., E.A.K., A.B.R., R.R.T., T.L.B., J.J.W.) and Neuroscience (A.S.R.), University of Wisconsin-Madison, Madison, Wisconsin
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Sagar MAK, Ouellette JN, Cheng KP, Williams JC, Watters JJ, Eliceiri KW. Microglia activation visualization via fluorescence lifetime imaging microscopy of intrinsically fluorescent metabolic cofactors. NEUROPHOTONICS 2020; 7:035003. [PMID: 32821772 PMCID: PMC7414793 DOI: 10.1117/1.nph.7.3.035003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 07/28/2020] [Indexed: 05/08/2023]
Abstract
Significance: A major obstacle to studying resident microglia has been their similarity to infiltrating immune cell types and the lack of unique protein markers for identifying the functional state. Given the role of microglia in all neural diseases and insults, accurate tools for detecting their function beyond morphologic alterations are necessary. Aims: We hypothesized that microglia would have unique metabolic fluxes in reduced nicotinamide adenine dinucleotide (NADH) that would be detectable by relative changes in fluorescence lifetime imaging microscopy (FLIM) parameters, allowing for identification of their activation status. Fluorescence lifetime of NADH has been previously demonstrated to show differences in metabolic fluxes. Approach: Here, we investigate the use of the label-free method of FLIM-based detection of the endogenous metabolic cofactor NADH to identify microglia and characterize their activation status. To test whether microglial activation would also confer a unique NADH lifetime signature, murine primary microglial cultures and adult mice were treated with lipopolysaccharide (LPS). Results: We found that LPS-induced microglia activation correlates with detected changes in NADH lifetime and its free-bound ratio. This indicates that NADH lifetime can be used to monitor microglia activation in a label-free fashion. Moreover, we found that there is an LPS dose-dependent change associated with reactive microglia lifetime fluxes, which is also replicated over time after LPS treatment. Conclusion: We have demonstrated a label-free way of monitoring microglia activation via quantifying lifetime of endogenous metabolic coenzyme NADH. Upon LPS-induced activation, there is a significant change in the fluorescence lifetime following activation. Together, these results indicate that NADH FLIM approaches can be used as a method to characterize microglia activation state, both in vitro and ex vivo.
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Affiliation(s)
- Md. Abdul K. Sagar
- University of Wisconsin-Madison, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | - Jonathan N. Ouellette
- University of Wisconsin-Madison, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | - Kevin P. Cheng
- University of Wisconsin-Madison, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | - Justin C. Williams
- University of Wisconsin-Madison, Department of Biomedical Engineering, Madison, Wisconsin, United States
| | - Jyoti J. Watters
- University of Wisconsin-Madison, Department of Comparative Biosciences, Madison, Wisconsin, United States
| | - Kevin W. Eliceiri
- University of Wisconsin-Madison, Department of Biomedical Engineering, Madison, Wisconsin, United States
- University of Wisconsin-Madison, Department of Medical Physics, Madison, Wisconsin, United States
- Morgridge Institute for Research, Madison, Wisconsin, United States
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Qian Y, Lei G, Wen L. Brain-specific deletion of TRIM13 promotes metabolic stress-triggered insulin resistance, glucose intolerance, and neuroinflammation. Biochem Biophys Res Commun 2020; 527:138-145. [PMID: 32446357 DOI: 10.1016/j.bbrc.2020.03.076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 03/12/2020] [Indexed: 11/26/2022]
Abstract
Diabetes has been associated with metabolic disorder, insulin resistance and neuroinflammation. However, the pathogenesis for HFD-induced injury of central nervous system (CNS) is still unclear. Tripartite Motif Containing 13 (TRIM13), also known as RFP2, is a member of TRIM proteins, and is associated with multiple cellular processes, such as apoptosis, survival and inflammation. However, the effects of TRIM13 on brain injury, especially the HFD-induced CNS damage, have not been investigated. To address this issue, the TRIM13flox/flox (fl/fl) mice were produced and then crossed them with Nestin-Cre mice to delete TRIM13 specifically in the brain (cKO). Then, T2D mice with obesity were established by chronic feeding of HFD. We found that brain-specific deletion of TRIM13 accelerated HFD-induced metabolic disorder, insulin resistance and systematic inflammatory response. In addition, HFDcKO mice exhibited significantly higher pro-inflammatory cytokines, including interleukin (IL)-6, IL-1β and tumor necrosis factor-α (TNF-α), in cortex, hippocampus and hypothalamus tissues, which were comparable to the HFDfl/fl mice. Consistently, the activation of nuclear factor-κB (NF-κB) induced by HFD was further aggravated in mice with brain-specific loss of TRIM13. Moreover, glial activation in CNS stimulated by HFD was further promoted by TRIM13 knockout in brain, as evidenced by the up-regulated expression of glial fibrillary acidic protein (GFAP) and Iba-1. In hypothalamus, HFD reduced proopiomelanocortin (POMC) and enhanced neuropeptide Y (NPY) expression, which were further promoted in mice with brain-specific deletion of TRIM13. Meanwhile, insulin signaling pathway was disrupted by HFD in hypothalamus of mice, and these effects were exacerbated in HFDcKO mice. The in vitro analysis confirmed that TRIM13 knockout in glial cells considerably promoted palmitate (PAL)-induced inflammatory response by accelerating NF-κB signal, contributing to the insulin resistance in the isolated primary neurons. Together, these findings demonstrated that TRIM13 was involved in HFD-induced CNS injury and insulin resistance through regulating neuroinflammatory response, contributing to the modulation of peripheral metabolic disorders.
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Affiliation(s)
- Yang Qian
- Department of Endocrine, The 521 Hospital of the China North Industries Group, Xi'an City, Shaanxi Province, 710065, China
| | - Gao Lei
- Department of Endocrinology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an City, Shaanxi Province, 710004, China
| | - Liu Wen
- Department of Geriatric, The First Affiliated Hospital of Dalian Medical University, Dalian City, Liaoning Province, 116011, China.
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Reiss D, Maduna T, Maurin H, Audouard E, Gaveriaux-Ruff C. Mu opioid receptor in microglia contributes to morphine analgesic tolerance, hyperalgesia, and withdrawal in mice. J Neurosci Res 2020; 100:203-219. [PMID: 32253777 DOI: 10.1002/jnr.24626] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 02/23/2020] [Accepted: 03/18/2020] [Indexed: 12/17/2022]
Abstract
A major challenge in medicine is developing potent pain therapies without the adverse effects of opiates. Neuroinflammation and in particular microglial activation have been shown to contribute to these effects. However, the implication of the microglial mu opioid receptor (MOR) is not known. We developed a novel conditional knockout (cKO) mouse line, wherein MOR is deleted in microglia. Morphine analgesic tolerance was delayed in both sexes in cKO mice in the hot plate assay. Opioid-induced hyperalgesia (OIH) as measured in the tail immersion assay was abolished in male cKO mice, and physical dependence to morphine as assessed by naloxone-induced withdrawal was attenuated in female cKO mice. Our results show a sex-dependent contribution of microglial MOR in morphine analgesic tolerance, OIH, and physical dependence. In conclusion, our data suggest that blockade of microglial MOR could represent a therapeutic target for opiate analgesia without the opiate adverse effects.
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Affiliation(s)
- David Reiss
- Translational Medicine and Neurogenetics Department, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,IGBMC, Université de Strasbourg, Illkirch, France.,UMR7104, Centre National de la Recherche Scientifique, Illkirch, France.,U1258, Institut National de la Santé et de la Recherche Médicale, Illkirch, France
| | - Tando Maduna
- Translational Medicine and Neurogenetics Department, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,IGBMC, Université de Strasbourg, Illkirch, France.,UMR7104, Centre National de la Recherche Scientifique, Illkirch, France.,U1258, Institut National de la Santé et de la Recherche Médicale, Illkirch, France.,Neurology Research Group, Department of Physiology, Stellenbosch University, Stellenbosch, South Africa
| | - Hervé Maurin
- Translational Medicine and Neurogenetics Department, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,IGBMC, Université de Strasbourg, Illkirch, France.,UMR7104, Centre National de la Recherche Scientifique, Illkirch, France.,U1258, Institut National de la Santé et de la Recherche Médicale, Illkirch, France
| | - Emilie Audouard
- Translational Medicine and Neurogenetics Department, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,IGBMC, Université de Strasbourg, Illkirch, France.,UMR7104, Centre National de la Recherche Scientifique, Illkirch, France.,U1258, Institut National de la Santé et de la Recherche Médicale, Illkirch, France
| | - Claire Gaveriaux-Ruff
- Translational Medicine and Neurogenetics Department, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,IGBMC, Université de Strasbourg, Illkirch, France.,UMR7104, Centre National de la Recherche Scientifique, Illkirch, France.,U1258, Institut National de la Santé et de la Recherche Médicale, Illkirch, France.,Ecole Supérieure de Biotechnologie de Strasbourg, Illkirch, France
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Yue H, Xie K, Ji X, Xu B, Wang C, Shi P. Vascularized neural constructs for ex-vivo reconstitution of blood-brain barrier function. Biomaterials 2020; 245:119980. [PMID: 32229330 DOI: 10.1016/j.biomaterials.2020.119980] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 03/08/2020] [Accepted: 03/17/2020] [Indexed: 01/30/2023]
Abstract
Ex-vivo blood-brain barrier (BBB) model is of great value for studying brain function and drug development, but it is still challenging to engineer macroscale three-dimensional (3D) tissue constructs to recapitulate physiological and functional aspects of BBB. Here, we describe a delicate 3D vascularized neural constructs for ex-vivo reconstitution of BBB function. The tissue-engineered tissue construct is based on a multicomponent 3D co-culture of four types of cells, which typically exist in the BBB and were spatially defined and organized to mimic the in vivo BBB structure and function. A porous polycaprolactone/poly (d,l-lactide-co-glycolide) (PCL/PLGA) microfluidic perfusion system works as the vasculature network, which was made by freeze-coating a 3D-printed sacrificial template. Endothelial cells were seeded inside the channels of the network to form 3D interconnected blood vessels; while other types of cells, including pericytes, astrocytes, and neurons, were co-cultured in a collagen matrix wrapping the vasculature network to derive a vascularized neural construct that recapitulates in vivo BBB function with great complexity and delicacy. Using this model, we successfully reconstituted BBB function with parameters that are similar to the in vivo condition, and demonstrated the identification of BBB-penetrating therapeutics by examining the molecular delivery to neuronal cells when relevant biologic molecules were applied to the vasculature circulation system of the neural construct.
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Affiliation(s)
- Haibing Yue
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong SAR, China
| | - Kai Xie
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong SAR, China
| | - Xianglin Ji
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong SAR, China
| | - Bingzhe Xu
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong SAR, China; School of Biomedical Engineering, Sun Yat-sen University, Guangzhou, 511434, China
| | - Chong Wang
- College of Mechanical Engineering, Dongguan University of Technology, Songshan Lake, Dongguan, 523808, China.
| | - Peng Shi
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong SAR, China; Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong SAR, China; Shenzhen Research Institute, City University of Hong Kong, Shenzhen, 518000, China.
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Halievski K, Ghazisaeidi S, Salter MW. Sex-Dependent Mechanisms of Chronic Pain: A Focus on Microglia and P2X4R. J Pharmacol Exp Ther 2020; 375:202-209. [DOI: 10.1124/jpet.120.265017] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 02/25/2020] [Indexed: 12/20/2022] Open
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Yao M, Ventura PB, Jiang Y, Rodriguez FJ, Wang L, Perry JSA, Yang Y, Wahl K, Crittenden RB, Bennett ML, Qi L, Gong CC, Li XN, Barres BA, Bender TP, Ravichandran KS, Janes KA, Eberhart CG, Zong H. Astrocytic trans-Differentiation Completes a Multicellular Paracrine Feedback Loop Required for Medulloblastoma Tumor Growth. Cell 2020; 180:502-520.e19. [PMID: 31983537 DOI: 10.1016/j.cell.2019.12.024] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 10/16/2019] [Accepted: 12/17/2019] [Indexed: 12/19/2022]
Abstract
The tumor microenvironment (TME) is critical for tumor progression. However, the establishment and function of the TME remain obscure because of its complex cellular composition. Using a mouse genetic system called mosaic analysis with double markers (MADMs), we delineated TME evolution at single-cell resolution in sonic hedgehog (SHH)-activated medulloblastomas that originate from unipotent granule neuron progenitors in the brain. First, we found that astrocytes within the TME (TuAstrocytes) were trans-differentiated from tumor granule neuron precursors (GNPs), which normally never differentiate into astrocytes. Second, we identified that TME-derived IGF1 promotes tumor progression. Third, we uncovered that insulin-like growth factor 1 (IGF1) is produced by tumor-associated microglia in response to interleukin-4 (IL-4) stimulation. Finally, we found that IL-4 is secreted by TuAstrocytes. Collectively, our studies reveal an evolutionary process that produces a multi-lateral network within the TME of medulloblastoma: a fraction of tumor cells trans-differentiate into TuAstrocytes, which, in turn, produce IL-4 that stimulates microglia to produce IGF1 to promote tumor progression.
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Affiliation(s)
- Maojin Yao
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - P Britten Ventura
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ying Jiang
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Fausto J Rodriguez
- Division of Neuropathology, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Lixin Wang
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Justin S A Perry
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Yibo Yang
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Kelsey Wahl
- Department of Biology, University of Oregon, Eugene, OR 97403, USA
| | - Rowena B Crittenden
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA; Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, VA 22908, USA
| | - Mariko L Bennett
- Department of Neurobiology, Stanford University, Palo Alto, CA 94305, USA
| | - Lin Qi
- Brain Tumor Program, Texas Children's Cancer Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Cong-Cong Gong
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Xiao-Nan Li
- Brain Tumor Program, Texas Children's Cancer Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ben A Barres
- Department of Neurobiology, Stanford University, Palo Alto, CA 94305, USA
| | - Timothy P Bender
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA; Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, VA 22908, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA; Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, VA 22908, USA; VIB-UGent Center for Inflammation Research and Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Kevin A Janes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Charles G Eberhart
- Division of Neuropathology, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hui Zong
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA.
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Microglia Adopt Longitudinal Transcriptional Changes After Traumatic Brain Injury. J Surg Res 2019; 246:113-122. [PMID: 31563831 DOI: 10.1016/j.jss.2019.08.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/18/2019] [Accepted: 08/29/2019] [Indexed: 11/20/2022]
Abstract
BACKGROUND Traumatic brain injury (TBI) is an under-recognized public health threat. Even mild brain injuries can lead to long-term neurologic impairment. Microglia play a fundamental role in the development and progression of this ensuing neurologic impairment. Despite this, a microglia-specific injury signature has yet to be identified. We hypothesized that TBI would lead to long-term changes in the transcriptional profile of microglial pathways associated with the development of subsequent neurologic impairment. MATERIALS AND METHODS Male C57BL/6 mice underwent TBI via a controlled cortical impact and were followed longitudinally. FACSorted microglia from TBI mice were subjected to Quantiseq 3'-biased RNA sequencing at 7, 30, and 90 d after TBI. K-means clustering on 396 differentially expressed genes was performed, and gene ontology enrichment analysis was used to determine corresponding enriched processes. RESULTS Differentially expressed genes in microglia exhibited four main patterns of expression over the course of TBI. In particular, we identified four gene clusters which corresponded to the host defense response, synaptic plasticity, lipid remodeling, and membrane polarization. CONCLUSIONS Transcriptional profiling within individual populations of microglia after TBI remains a critical unmet research need within the field of TBI. This focused study identified several physiologic processes within microglia that may be associated with development of long-term neurologic impairment after TBI. These data demonstrate the capability of longitudinal transcriptional profiling to uncover potential cell-specific targets for the treatment of TBI.
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Kosior N, Petkau TL, Connolly C, Lu G, Leavitt BR. Isolating cells from adult murine brain for validation of cell-type specific cre-mediated deletion. J Neurosci Methods 2019; 328:108422. [PMID: 31493416 DOI: 10.1016/j.jneumeth.2019.108422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 09/03/2019] [Accepted: 09/03/2019] [Indexed: 01/05/2023]
Abstract
BACKGROUND TheCre/loxP system allows for the temporal and spatial investigation of the expression of a single gene in the nervous system. Current methods of validating conditional knock-out mouse models rely on heterogeneous brain tissue or primary culture. These methods may assess the extent of genetic knockdown in the brain but do not provide age-appropriate, cell-type specific information. NEW METHOD We isolated specific cell types from adult murine brain using FACS to assess cell type-specific gene expression in conditional mouse models. RESULTS We identified robust but incomplete genetic knockdown in microglia isolated from two separate microglia-specific knockout models. COMPARISONWITH EXISTING METHODS(S) Genetic knockdown in isolated adult microglia differed significantly from cultured primary microglia. CONCLUSIONS Differences observed in primary cultured microglia compared to isolated adult microglia suggest that current methods used to validate microglia-specific gene deletion over-estimate deletion efficiency. Assessment of gene expression in isolated adult microglia provides a more accurate assessment of Cre-mediated gene deletion.
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Affiliation(s)
- Natalia Kosior
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia and Children's and Women's Hospital, 980 West 28thAvenue, Vancouver, BC, V5Z 4H4, Canada
| | - Terri L Petkau
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia and Children's and Women's Hospital, 980 West 28thAvenue, Vancouver, BC, V5Z 4H4, Canada
| | - Colúm Connolly
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia and Children's and Women's Hospital, 980 West 28thAvenue, Vancouver, BC, V5Z 4H4, Canada
| | - Ge Lu
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia and Children's and Women's Hospital, 980 West 28thAvenue, Vancouver, BC, V5Z 4H4, Canada
| | - Blair R Leavitt
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia and Children's and Women's Hospital, 980 West 28thAvenue, Vancouver, BC, V5Z 4H4, Canada; Division of Neurology, Department of Medicine, University of British Columbia Hospital, S 192-2211 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada; Brain Research Center, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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45
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Sommer D, Corstjens I, Sanchez S, Dooley D, Lemmens S, Van Broeckhoven J, Bogie J, Vanmierlo T, Vidal PM, Rose-John S, Gou-Fabregas M, Hendrix S. ADAM17-deficiency on microglia but not on macrophages promotes phagocytosis and functional recovery after spinal cord injury. Brain Behav Immun 2019; 80:129-145. [PMID: 30851378 DOI: 10.1016/j.bbi.2019.02.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/12/2019] [Accepted: 02/27/2019] [Indexed: 12/26/2022] Open
Abstract
A disintegrin and metalloproteinase 17 (ADAM17) is the major sheddase involved in the cleavage of a plethora of cytokines, cytokine receptors and growth factors, thereby playing a substantial role in inflammatory and regenerative processes after central nervous system trauma. By making use of a hypomorphic ADAM17 knockin mouse model as well as pharmacological ADAM10/ADAM17 inhibitors, we showed that ADAM17-deficiency or inhibition significantly increases clearance of apoptotic cells, promotes axon growth and improves functional recovery after spinal cord injury (SCI) in mice. Microglia-specific ADAM17-knockout (ADAM17flox+/+-Cx3Cr1 Cre+/-) mice also showed improved functional recovery similar to hypomorphic ADAM17 mice. In contrast, endothelial-specific (ADAM17flox+/+-Cdh5Pacs Cre+/-) and macrophage-specific (ADAM17flox+/+-LysM Cre+/-) ADAM17-knockout mice or bone marrow chimera with transplanted ADAM17-deficient macrophages, displayed no functional improvement compared to wild type mice. These data indicate that ADAM17 expression on microglia cells (and not on macrophages or endothelial cells) plays a detrimental role in inflammation and functional recovery after SCI.
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Affiliation(s)
- Daniela Sommer
- Biomedical Research Institute, Hasselt University, 3500 Hasselt, Belgium
| | - Inge Corstjens
- Biomedical Research Institute, Hasselt University, 3500 Hasselt, Belgium
| | - Selien Sanchez
- Biomedical Research Institute, Hasselt University, 3500 Hasselt, Belgium
| | - Dearbhaile Dooley
- Health Science Centre, School of Medicine, University College Dublin, Dublin 4, Ireland
| | - Stefanie Lemmens
- Biomedical Research Institute, Hasselt University, 3500 Hasselt, Belgium
| | | | - Jeroen Bogie
- Biomedical Research Institute, Hasselt University, 3500 Hasselt, Belgium
| | - Tim Vanmierlo
- Biomedical Research Institute, Hasselt University, 3500 Hasselt, Belgium; Division of Translational Neuroscience, MHeNs, Maastricht University, 6229ER Maastricht, the Netherlands
| | - Pia M Vidal
- Laboratory of Neuroimmunology, Fundación Ciencia & Vida, 7780272 Santiago, Chile
| | - Stefan Rose-John
- Institute of Biochemistry, Christian-Albrechts University Kiel, 24098 Kiel, Germany
| | | | - Sven Hendrix
- Biomedical Research Institute, Hasselt University, 3500 Hasselt, Belgium.
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46
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Kiernan EA, Wang T, Vanderplow AM, Cherukuri S, Cahill ME, Watters JJ. Neonatal Intermittent Hypoxia Induces Lasting Sex-Specific Augmentation of Rat Microglial Cytokine Expression. Front Immunol 2019; 10:1479. [PMID: 31333645 PMCID: PMC6615134 DOI: 10.3389/fimmu.2019.01479] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/13/2019] [Indexed: 01/08/2023] Open
Abstract
Sleep disordered breathing (SDB) affects 3-5% of the pediatric population, including neonates who are highly susceptible due to an underdeveloped ventilatory control system, and REM-dominated sleep. Although pediatric SDB is associated with poor cognitive outcomes, very little research has focused on models of pediatric SDB, particularly in neonates. In adults and neonates, intermittent hypoxia (IH), a hallmark of SDB, recapitulates multiple physiological aspects of severe SDB, including neuronal apoptosis, sex-specific cognitive deficits, and neuroinflammation. Microglia, resident CNS immune cells, are important mediators of neurodevelopment and neuroinflammation, but to date, no studies have examined the molecular properties of microglia in the context of neonatal IH. Here, we tested the hypothesis that neonatal IH will enhance microglial inflammation and sex-specifically lead to long-term changes in working memory. To test this hypothesis, we exposed post-natal day (P1) neonates with dams to an established adult model of pathological IH consisting of 2 min cycles of 10.5% O2 followed by 21% O2, 8 h/day for 8 days. We then challenged the offspring with bacterial lipopolysaccharide (LPS) at P9 or at 6-8 weeks of age and immunomagnetically isolated microglia for gene expression analyses and RNA-sequencing. We also characterized neonatal CNS myeloid cell populations by flow cytometry analyses. Lastly, we examined working memory performance using a Y-maze in the young adults. Contrary to our hypothesis, we found that neonatal IH acutely augmented basal levels of microglial anti-inflammatory cytokines, attenuated microglial responses to LPS, and sex-specifically altered CNS myeloid populations. We identified multiple sex differences in basal neonatal microglial expression of genes related to chemotaxis, cognition, and aging. Lastly, we found that basal, but not LPS-induced, anti-inflammatory cytokines were augmented sex-specifically in the young adults, and that there was a significant interaction between sex and IH on basal working memory. Our results support the idea that neonates may be able to adapt to IH exposures that are pathological in adults. Further, they suggest that male and female microglial responses to IH are sex-specific, and that these sex differences in basal microglial gene expression may contribute to sexual dimorphisms in vulnerability to IH-induced cognitive disruption.
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Affiliation(s)
- Elizabeth A Kiernan
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, United States
| | - Tao Wang
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Amanda M Vanderplow
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Sneha Cherukuri
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Michael E Cahill
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, United States.,Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Jyoti J Watters
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, United States.,Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, United States
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47
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Abstract
Supplemental Digital Content is Available in the Text. Glial inhibitors only reverse mechanical hypersensitivity in male mice subjected to arthritis. No obvious arthritis-related transcriptional difference was identified between male and female spinal microglia. Recent studies have suggested a sexually dimorphic role of spinal glial cells in the maintenance of mechanical hypersensitivity in rodent models of chronic pain. We have used the collagen antibody–induced arthritis (CAIA) mouse model to examine differences between males and females in the context of spinal regulation of arthritis-induced pain. We have focused on the late phase of this model when joint inflammation has resolved, but mechanical hypersensitivity persists. Although the intensity of substance P, calcitonin gene–related peptide, and galanin immunoreactivity in the spinal cord was not different from controls, the intensity of microglia (Iba-1) and astrocyte (glial fibrillary acidic protein) markers was elevated in both males and females. Intrathecal administration of the glial inhibitors minocycline and pentoxifylline reversed mechanical thresholds in male, but not in female mice. We isolated resident microglia from the lumbar dorsal horns and observed a significantly lower number of microglial cells in females by flow cytometry analysis. However, although genome-wide RNA sequencing results pointed to several transcriptional differences between male and female microglia, no convincing differences were identified between control and CAIA groups. Taken together, these findings suggest that there are subtle sex differences in microglial expression profiles independent of arthritis. Our experiments failed to identify the underlying mRNA correlates of microglial actions in the late phase of the CAIA model. It is likely that transcriptional changes are either subtle and highly localised and therefore difficult to identify with bulk isolation techniques or that other factors, such as changes in protein expression or epigenetic modifications, are at play.
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Petrillo C, Calabria A, Piras F, Capotondo A, Spinozzi G, Cuccovillo I, Benedicenti F, Naldini L, Montini E, Biffi A, Gentner B, Kajaste-Rudnitski A. Assessing the Impact of Cyclosporin A on Lentiviral Transduction and Preservation of Human Hematopoietic Stem Cells in Clinically Relevant Ex Vivo Gene Therapy Settings. Hum Gene Ther 2019; 30:1133-1146. [PMID: 31037976 PMCID: PMC6761585 DOI: 10.1089/hum.2019.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Improving hematopoietic stem and progenitor cell (HSPC) permissiveness to lentiviral vector (LV) transduction without compromising their biological properties remains critical for broad-range implementation of gene therapy as a treatment option for several inherited diseases. This study demonstrates that the use of one-hit ex vivo LV transduction protocols based on either cyclosporin A (CsA) or rapamycin enable as efficient gene transfer as the current two-hit clinical standard into bone marrow-derived CD34+ cells while better preserving their engraftment capacity in vivo. CsA was additive with another enhancer of transduction, prostaglandin E2, suggesting that tailored enhancer combinations may be applied to overcome multiple blocks to transduction simultaneously in HSPC. Interestingly, besides enhancing LV transduction, CsA also significantly reduced HSPC proliferation, preserving the quiescent G0 fraction and the more primitive multipotent progenitors, thereby yielding the highest engraftment levels in vivo. Importantly, no alterations in the vector integration profiles could be detected between CsA and control transduced HSPC. Overall, the present findings contribute to the development of more efficient and sustainable LV gene therapy protocols, underscoring the benefits of scaling down required vector doses, as well as shortening the HSPC ex vivo culture time.
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Affiliation(s)
- Carolina Petrillo
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy.,Vita-Salute San Raffaele University, School of Medicine, Milan, Italy
| | - Andrea Calabria
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Francesco Piras
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy.,Vita-Salute San Raffaele University, School of Medicine, Milan, Italy
| | - Alessia Capotondo
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Giulio Spinozzi
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Ivan Cuccovillo
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Fabrizio Benedicenti
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Luigi Naldini
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy.,Vita-Salute San Raffaele University, School of Medicine, Milan, Italy
| | - Eugenio Montini
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Alessandra Biffi
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy.,Gene Therapy Program, Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston, Massachusetts.,Program for Gene Therapy in Rare Diseases, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts
| | - Bernhard Gentner
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy
| | - Anna Kajaste-Rudnitski
- San Raffaele Telethon Institute for Gene Therapy (SR-TIGET), IRCCS Ospedale San Raffaele, Milan, Italy
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49
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Zhang X, He Q, Huang T, Zhao N, Liang F, Xu B, Chen X, Li T, Bi J. Treadmill Exercise Decreases Aβ Deposition and Counteracts Cognitive Decline in APP/PS1 Mice, Possibly via Hippocampal Microglia Modifications. Front Aging Neurosci 2019; 11:78. [PMID: 31024293 PMCID: PMC6461026 DOI: 10.3389/fnagi.2019.00078] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 03/19/2019] [Indexed: 12/31/2022] Open
Abstract
Recent studies have suggested that exercise may be beneficial for delaying or attenuating Alzheimer's disease (AD). However, the underlying mechanisms were not clear. Microglia-mediated neuroinflammation is suggested to play an important role in the pathology of AD. The present study investigated the beneficial effects of treadmill exercise on amyloid-β (Aβ) deposition and cognitive function in amyloid precursor protein (APP)/PS1 mice in the early stage of AD progression and microglia-mediated neuroinflammation was mainly analyzed. The results demonstrated that 12 weeks of treadmill exercise preserved hippocampal cognitive function in APP/PS1 mice and substantially suppressed Aβ accumulation in the hippocampus. Treadmill exercise significantly inhibited neuroinflammation, which was characterized by a remarkably reduced expression of pro-inflammatory factors and increased expression of anti-inflammatory mediators in the hippocampus, resulting from a shift in activated microglia from the M1 to M2 phenotype. Treadmill exercise also attenuated oxidative stress presented by a marked reduction in methane dicarboxylic aldehyde (MDA) level and dramatically elevated SOD and Mn-SOD activities in the hippocampus. These findings suggest that treadmill exercise can effectively prevent the decrease in hippocampal-dependent cognitive function and Aβ deposits in early AD progression possibly via modulating microglia-mediated neuroinflammation and oxidative stress.
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Affiliation(s)
| | - Qiang He
- College of Physical Education, Shandong Normal University, Jinan, China
| | - Tao Huang
- Department of Physical Education, Shanghai Jiao Tong University, Shanghai, China
| | - Na Zhao
- School of Physical Education & Health Care, East China Normal University, Shanghai, China
| | - Fei Liang
- School of Physical Education & Health Care, East China Normal University, Shanghai, China
| | - Bo Xu
- School of Physical Education & Health Care, East China Normal University, Shanghai, China
| | - Xianghe Chen
- College of Physical Education, Yangzhou University, Yangzhou, China
| | | | - Jianzhong Bi
- Department of Neurology Medicine, Shandong University, Jinan, China
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50
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Brifault C, Kwon H, Campana WM, Gonias SL. LRP1 deficiency in microglia blocks neuro-inflammation in the spinal dorsal horn and neuropathic pain processing. Glia 2019; 67:1210-1224. [PMID: 30746765 DOI: 10.1002/glia.23599] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 12/18/2018] [Accepted: 01/22/2019] [Indexed: 01/29/2023]
Abstract
Following injury to the peripheral nervous system (PNS), microglia in the spinal dorsal horn (SDH) become activated and contribute to the development of local neuro-inflammation, which may regulate neuropathic pain processing. The molecular mechanisms that control microglial activation and its effects on neuropathic pain remain incompletely understood. We deleted the gene encoding the plasma membrane receptor, LDL Receptor-related Protein-1 (LRP1), conditionally in microglia using two distinct promoter-Cre recombinase systems in mice. LRP1 deletion in microglia blocked development of tactile allodynia, a neuropathic pain-related behavior, after partial sciatic nerve ligation (PNL). LRP1 deletion also substantially attenuated microglial activation and pro-inflammatory cytokine expression in the SDH following PNL. Because LRP1 shedding from microglial plasma membranes generates a highly pro-inflammatory soluble product, we demonstrated that factors which activate spinal cord microglia, including lipopolysaccharide (LPS) and colony-stimulating factor-1, promote LRP1 shedding. Proteinases known to mediate LRP1 shedding, including ADAM10 and ADAM17, were expressed at increased levels in the SDH after PNL. Furthermore, LRP1-deficient microglia in cell culture expressed significantly decreased levels of interleukin-1β and interleukin-6 when treated with LPS. We conclude that in the SDH, microglial LRP1 plays an important role in establishing and/or amplifying local neuro-inflammation and neuropathic pain following PNS injury. The responsible mechanism most likely involves proteolytic release of LRP1 from the plasma membrane to generate a soluble product that functions similarly to pro-inflammatory cytokines in mediating crosstalk between cells in the SDH and in regulating neuropathic pain.
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Affiliation(s)
- Coralie Brifault
- Department of Pathology, University of California San Diego, La Jolla, California.,Department of Anesthesiology, University of California San Diego, La Jolla, California
| | - HyoJun Kwon
- Department of Anesthesiology, University of California San Diego, La Jolla, California
| | - Wendy M Campana
- Department of Anesthesiology, University of California San Diego, La Jolla, California.,Department of Anesthesiology, Veterans Administration San Diego HealthCare System, San Diego, California
| | - Steven L Gonias
- Department of Pathology, University of California San Diego, La Jolla, California
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