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Li P, Zhao J, Ma Y, Wang L, Liang S, Fan F, Wei T, Feng L, Hu X, Hu Y, Wang Z, Qin H. Transplantation of miR-145a-5p modified M2 type microglia promotes the tissue repair of spinal cord injury in mice. J Transl Med 2024; 22:724. [PMID: 39103885 DOI: 10.1186/s12967-024-05492-1] [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: 02/21/2024] [Accepted: 07/07/2024] [Indexed: 08/07/2024] Open
Abstract
BACKGROUND The traumatic spinal cord injury (SCI) can cause immediate multi-faceted function loss or paralysis. Microglia, as one of tissue resident macrophages, has been reported to play a critical role in regulating inflammation response during SCI processes. And transplantation with M2 microglia into SCI mice promotes recovery of motor function. However, the M2 microglia can be easily re-educated and changed their phenotype due to the stimuli of tissue microenvironment. This study aimed to find a way to maintain the function of M2 microglia, which could exert an anti-inflammatory and pro-repair role, and further promote the repair of spinal cord injury. METHODS To establish a standard murine spinal cord clip compression model using Dumont tying forceps. Using FACS, to sort microglia from C57BL/6 mice or CX3CR1GFP mice, and further culture them in vitro with different macrophage polarized medium. Also, to isolate primary microglia using density gradient centrifugation with the neonatal mice. To transfect miR-145a-5p into M2 microglia by Lipofectamine2000, and inject miR-145a-5p modified M2 microglia into the lesion sites of spinal cord for cell transplanted therapy. To evaluate the recovery of motor function in SCI mice through behavior analysis, immunofluorescence or histochemistry staining, Western blot and qRT-PCR detection. Application of reporter assay and molecular biology experiments to reveal the mechanism of miR-145a-5p modified M2 microglia therapy on SCI mice. RESULTS With in vitro experiments, we found that miR-145a-5p was highly expressed in M2 microglia, and miR-145a-5p overexpression could suppress M1 while promote M2 microglia polarization. And then delivery of miR-145a-5p overexpressed M2 microglia into the injured spinal cord area significantly accelerated locomotive recovery as well as prevented glia scar formation and neuron damage in mice, which was even better than M2 microglia transplantation. Further mechanisms showed that overexpressed miR-145a-5p in microglia inhibited the inflammatory response and maintained M2 macrophage phenotype by targeting TLR4/NF-κB signaling. CONCLUSIONS These findings indicate that transplantation of miR-145a-5p modified M2 microglia has more therapeutic potential for SCI than M2 microglia transplantation from epigenetic perspective.
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Affiliation(s)
- Penghui Li
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
- State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, 710032, China
| | - Junlong Zhao
- State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, 710032, China
| | - Yangguang Ma
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Liang Wang
- State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, 710032, China
| | - Shiqian Liang
- State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, 710032, China
| | - Fan Fan
- State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, 710032, China
| | - Tiaoxia Wei
- State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, 710032, China
| | - Lei Feng
- State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, 710032, China
| | - Xueyu Hu
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Yiyang Hu
- State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, 710032, China.
| | - Zhe Wang
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
| | - Hongyan Qin
- State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, 710032, China.
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Desmond LW, Holbrook EM, Wright CTO, Zambrano CA, Stamper CE, Bohr AD, Frank MG, Podell BK, Moreno JA, MacDonald AS, Reber SO, Hernández-Pando R, Lowry CA. Effects of Mycobacterium vaccae NCTC 11659 and Lipopolysaccharide Challenge on Polarization of Murine BV-2 Microglial Cells. Int J Mol Sci 2023; 25:474. [PMID: 38203645 PMCID: PMC10779110 DOI: 10.3390/ijms25010474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/15/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024] Open
Abstract
Previous studies have shown that the in vivo administration of soil-derived bacteria with anti-inflammatory and immunoregulatory properties, such as Mycobacterium vaccae NCTC 11659, can prevent a stress-induced shift toward an inflammatory M1 microglial immunophenotype and microglial priming in the central nervous system (CNS). It remains unclear whether M. vaccae NCTC 11659 can act directly on microglia to mediate these effects. This study was designed to determine the effects of M. vaccae NCTC 11659 on the polarization of naïve BV-2 cells, a murine microglial cell line, and BV-2 cells subsequently challenged with lipopolysaccharide (LPS). Briefly, murine BV-2 cells were exposed to 100 µg/mL whole-cell, heat-killed M. vaccae NCTC 11659 or sterile borate-buffered saline (BBS) vehicle, followed, 24 h later, by exposure to 0.250 µg/mL LPS (Escherichia coli 0111: B4; n = 3) in cell culture media vehicle (CMV) or a CMV control condition. Twenty-four hours after the LPS or CMV challenge, cells were harvested to isolate total RNA. An analysis using the NanoString platform revealed that, by itself, M. vaccae NCTC 11659 had an "adjuvant-like" effect, while exposure to LPS increased the expression of mRNAs encoding proinflammatory cytokines, chemokine ligands, the C3 component of complement, and components of inflammasome signaling such as Nlrp3. Among LPS-challenged cells, M. vaccae NCTC 11659 had limited effects on differential gene expression using a threshold of 1.5-fold change. A subset of genes was assessed using real-time reverse transcription polymerase chain reaction (real-time RT-PCR), including Arg1, Ccl2, Il1b, Il6, Nlrp3, and Tnf. Based on the analysis using real-time RT-PCR, M. vaccae NCTC 11659 by itself again induced "adjuvant-like" effects, increasing the expression of Il1b, Il6, and Tnf while decreasing the expression of Arg1. LPS by itself increased the expression of Ccl2, Il1b, Il6, Nlrp3, and Tnf while decreasing the expression of Arg1. Among LPS-challenged cells, M. vaccae NCTC 11659 enhanced LPS-induced increases in the expression of Nlrp3 and Tnf, consistent with microglial priming. In contrast, among LPS-challenged cells, although M. vaccae NCTC 11659 did not fully prevent the effects of LPS relative to vehicle-treated control conditions, it increased Arg1 mRNA expression, suggesting that M. vaccae NCTC 11659 induces an atypical microglial phenotype. Thus, M. vaccae NCTC 11659 acutely (within 48 h) induced immune-activating and microglial-priming effects when applied directly to murine BV-2 microglial cells, in contrast to its long-term anti-inflammatory and immunoregulatory effects observed on the CNS when whole-cell, heat-killed preparations of M. vaccae NCTC 11659 were given peripherally in vivo.
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Affiliation(s)
- Luke W. Desmond
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; (L.W.D.); (E.M.H.); (C.T.O.W.); (C.A.Z.); (C.E.S.); (A.D.B.); (M.G.F.)
| | - Evan M. Holbrook
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; (L.W.D.); (E.M.H.); (C.T.O.W.); (C.A.Z.); (C.E.S.); (A.D.B.); (M.G.F.)
| | - Caelan T. O. Wright
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; (L.W.D.); (E.M.H.); (C.T.O.W.); (C.A.Z.); (C.E.S.); (A.D.B.); (M.G.F.)
| | - Cristian A. Zambrano
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; (L.W.D.); (E.M.H.); (C.T.O.W.); (C.A.Z.); (C.E.S.); (A.D.B.); (M.G.F.)
| | - Christopher E. Stamper
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; (L.W.D.); (E.M.H.); (C.T.O.W.); (C.A.Z.); (C.E.S.); (A.D.B.); (M.G.F.)
| | - Adam D. Bohr
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; (L.W.D.); (E.M.H.); (C.T.O.W.); (C.A.Z.); (C.E.S.); (A.D.B.); (M.G.F.)
| | - Matthew G. Frank
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; (L.W.D.); (E.M.H.); (C.T.O.W.); (C.A.Z.); (C.E.S.); (A.D.B.); (M.G.F.)
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Brendan K. Podell
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA;
| | - Julie A. Moreno
- Prion Research Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA;
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
- Center for Healthy Aging, Colorado State University, Fort Collins, CO 80523, USA
| | - Andrew S. MacDonald
- Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester M13 9NT, UK;
| | - Stefan O. Reber
- Laboratory for Molecular Psychosomatics, Department of Psychosomatic Medicine and Psychotherapy, Ulm University Medical Center, 89081 Ulm, Germany;
| | - Rogelio Hernández-Pando
- Sección de Patología Experimental, Departamento de Patología, Instituto Nacional De Ciencias Médicas Y Nutrición Salvador Zubirán, Ciudad de México 14080, Mexico;
| | - Christopher A. Lowry
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; (L.W.D.); (E.M.H.); (C.T.O.W.); (C.A.Z.); (C.E.S.); (A.D.B.); (M.G.F.)
- Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA
- Center for Microbial Exploration, University of Colorado Boulder, Boulder, CO 80309, USA
- Department of Physical Medicine and Rehabilitation and Center for Neuroscience, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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Lepiarz-Raba I, Gbadamosi I, Florea R, Paolicelli RC, Jawaid A. Metabolic regulation of microglial phagocytosis: Implications for Alzheimer's disease therapeutics. Transl Neurodegener 2023; 12:48. [PMID: 37908010 PMCID: PMC10617244 DOI: 10.1186/s40035-023-00382-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 10/23/2023] [Indexed: 11/02/2023] Open
Abstract
Microglia, the resident immune cells of the brain, are increasingly implicated in the regulation of brain health and disease. Microglia perform multiple functions in the central nervous system, including surveillance, phagocytosis and release of a variety of soluble factors. Importantly, a majority of their functions are closely related to changes in their metabolism. This natural inter-dependency between core microglial properties and metabolism offers a unique opportunity to modulate microglial activities via nutritional or metabolic interventions. In this review, we examine the existing scientific literature to synthesize the hypothesis that microglial phagocytosis of amyloid beta (Aβ) aggregates in Alzheimer's disease (AD) can be selectively enhanced via metabolic interventions. We first review the basics of microglial metabolism and the effects of common metabolites, such as glucose, lipids, ketone bodies, glutamine, pyruvate and lactate, on microglial inflammatory and phagocytic properties. Next, we examine the evidence for dysregulation of microglial metabolism in AD. This is followed by a review of in vivo studies on metabolic manipulation of microglial functions to ascertain their therapeutic potential in AD. Finally, we discuss the effects of metabolic factors on microglial phagocytosis of healthy synapses, a pathological process that also contributes to the progression of AD. We conclude by enlisting the current challenges that need to be addressed before strategies to harness microglial phagocytosis to clear pathological protein deposits in AD and other neurodegenerative disorders can be widely adopted.
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Affiliation(s)
- Izabela Lepiarz-Raba
- Laboratory for Translational Research in Neuropsychiatric Disorders (TREND), BRAINCITY: Center of Excellence for Neural Plasticity and Brain Disorders, Nencki Institute of Experimental Biology, Warsaw, Poland.
| | - Ismail Gbadamosi
- Laboratory for Translational Research in Neuropsychiatric Disorders (TREND), BRAINCITY: Center of Excellence for Neural Plasticity and Brain Disorders, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Roberta Florea
- Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
| | | | - Ali Jawaid
- Laboratory for Translational Research in Neuropsychiatric Disorders (TREND), BRAINCITY: Center of Excellence for Neural Plasticity and Brain Disorders, Nencki Institute of Experimental Biology, Warsaw, Poland.
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Li H, Huynh TN, Duong MT, Gow JG, Chang CCY, Chang TY. ACAT1/SOAT1 Blockade Suppresses LPS-Mediated Neuroinflammation by Modulating the Fate of Toll-like Receptor 4 in Microglia. Int J Mol Sci 2023; 24:5616. [PMID: 36982689 PMCID: PMC10053317 DOI: 10.3390/ijms24065616] [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: 02/10/2023] [Revised: 03/08/2023] [Accepted: 03/08/2023] [Indexed: 03/17/2023] Open
Abstract
Cholesterol is stored as cholesteryl esters by the enzymes acyl-CoA:cholesterol acyltransferases/sterol O:acyltransferases (ACATs/SOATs). ACAT1 blockade (A1B) ameliorates the pro-inflammatory responses of macrophages to lipopolysaccharides (LPS) and cholesterol loading. However, the mediators involved in transmitting the effects of A1B in immune cells is unknown. Microglial Acat1/Soat1 expression is elevated in many neurodegenerative diseases and in acute neuroinflammation. We evaluated LPS-induced neuroinflammation experiments in control vs. myeloid-specific Acat1/Soat1 knockout mice. We also evaluated LPS-induced neuroinflammation in microglial N9 cells with and without pre-treatment with K-604, a selective ACAT1 inhibitor. Biochemical and microscopy assays were used to monitor the fate of Toll-Like Receptor 4 (TLR4), the receptor at the plasma membrane and the endosomal membrane that mediates pro-inflammatory signaling cascades. In the hippocampus and cortex, results revealed that Acat1/Soat1 inactivation in myeloid cell lineage markedly attenuated LPS-induced activation of pro-inflammatory response genes. Studies in microglial N9 cells showed that pre-incubation with K-604 significantly reduced the LPS-induced pro-inflammatory responses. Further studies showed that K-604 decreased the total TLR4 protein content by increasing TLR4 endocytosis, thus enhancing the trafficking of TLR4 to the lysosomes for degradation. We concluded that A1B alters the intracellular fate of TLR4 and suppresses its pro-inflammatory signaling cascade in response to LPS.
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Affiliation(s)
- Haibo Li
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Thao N. Huynh
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Michael Tran Duong
- Department of Bioengineering, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James G. Gow
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Catherine C. Y. Chang
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Ta Yuan Chang
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
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Thu Thuy Nguyen V, Endres K. Targeting gut microbiota to alleviate neuroinflammation in Alzheimer's disease. Adv Drug Deliv Rev 2022; 188:114418. [PMID: 35787390 DOI: 10.1016/j.addr.2022.114418] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 02/08/2023]
Abstract
The gut microbiota came into focus within the last years regarding being associated with or even underlying neuropsychiatric diseases. The existence of the gut-brain-axis makes it highly plausible that bacterial metabolites or toxins that escape the intestinal environment or approach the vagal connections towards the brain, exert devastating effects on the central nervous system. In Alzheimer's disease (AD), growing evidence for dysbiotic changes in the gut microbiota is obtained, even though the question for cause or consequence remains open. Nevertheless, using modulation of microbiota to address inflammatory processes seems an attractive therapeutic approach as certain microbial products such as short chain fatty acids have been proven to exert beneficial cognitive effects. In this review, we summarize, contemporary knowledge on neuroinflammation and inflammatory processes within the brain and even more detailed in the gut in AD, try to conclude whom to target regarding human microbial commensals and report on current interventional trials.
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Affiliation(s)
- Vu Thu Thuy Nguyen
- Department of Psychiatry and Psychotherapy, University Medical Center Mainz, Johannes Gutenberg-University Mainz, Germany
| | - Kristina Endres
- Department of Psychiatry and Psychotherapy, University Medical Center Mainz, Johannes Gutenberg-University Mainz, Germany.
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Roles of Fatty Acids in Microglial Polarization: Evidence from In Vitro and In Vivo Studies on Neurodegenerative Diseases. Int J Mol Sci 2022; 23:ijms23137300. [PMID: 35806302 PMCID: PMC9266841 DOI: 10.3390/ijms23137300] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 06/24/2022] [Accepted: 06/28/2022] [Indexed: 02/04/2023] Open
Abstract
Microglial polarization to the M1 phenotype (classically activated) or the M2 phenotype (alternatively activated) is critical in determining the fate of immune responses in neurodegenerative diseases (NDs). M1 macrophages contribute to neurotoxicity, neuronal and synaptic damage, and oxidative stress and are the first line of defense, and M2 macrophages elicit an anti-inflammatory response to regulate neuroinflammation, clear cell debris, and promote neuroregeneration. Various studies have focused on the ability of natural compounds to promote microglial polarization from the M1 phenotype to the M2 phenotype in several diseases, including NDs. However, studies on the roles of fatty acids in microglial polarization and their implications in NDs are a rare find. Most of the studies support the role of polyunsaturated fatty acids (PUFAs) in microglial polarization using cell and animal models. Thus, we aimed to collect data and provide a narrative account of microglial types, markers, and studies pertaining to fatty acids, particularly PUFAs, on microglial polarization and their neuroprotective effects. The involvement of only PUFAs in the chosen topic necessitates more in-depth research into the role of unexplored fatty acids in microglial polarization and their mechanistic implications. The review also highlights limitations and future challenges.
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Microglia in Neurodegenerative Events-An Initiator or a Significant Other? Int J Mol Sci 2021; 22:ijms22115818. [PMID: 34072307 PMCID: PMC8199265 DOI: 10.3390/ijms22115818] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/22/2021] [Accepted: 05/25/2021] [Indexed: 02/06/2023] Open
Abstract
A change in microglia structure, signaling, or function is commonly associated with neurodegeneration. This is evident in the patient population, animal models, and targeted in vitro assays. While there is a clear association, it is not evident that microglia serve as an initiator of neurodegeneration. Rather, the dynamics imply a close interaction between the various cell types and structures in the brain that orchestrate the injury and repair responses. Communication between microglia and neurons contributes to the physiological phenotype of microglia maintaining cells in a surveillance state and allows the cells to respond to events occurring in their environment. Interactions between microglia and astrocytes is not as well characterized, nor are interactions with other members of the neurovascular unit; however, given the influence of systemic factors on neuroinflammation and disease progression, such interactions likely represent significant contributes to any neurodegenerative process. In addition, they offer multiple target sites/processes by which environmental exposures could contribute to neurodegenerative disease. Thus, microglia at least play a role as a significant other with an equal partnership; however, claiming a role as an initiator of neurodegeneration remains somewhat controversial.
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Xue Y, Nie D, Wang LJ, Qiu HC, Ma L, Dong MX, Tu WJ, Zhao J. Microglial Polarization: Novel Therapeutic Strategy against Ischemic Stroke. Aging Dis 2021; 12:466-479. [PMID: 33815877 PMCID: PMC7990355 DOI: 10.14336/ad.2020.0701] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 07/01/2020] [Indexed: 12/12/2022] Open
Abstract
Ischemic stroke, which is the second highest cause of death and the leading cause of disability, represents ~71% of all strokes globally. Some studies have found that the key elements of the pathobiology of stroke is immunity and inflammation. Microglia are the first line of defense in the nervous system. After stroke, the activated microglia become a double-edged sword, with distinct phenotypic changes to the deleterious M1 types and neuroprotective M2 types. Therefore, ways to promote microglial polarization toward M2 phenotype after stroke have become the focus of attention in recent years. In this review, we discuss the process of microglial polarization, summarize the alternation of signaling pathways and epigenetic regulation that control microglial polarization in ischemic stroke, aiming to find the potential mechanisms by which microglia can be transformed into the M2 polarized phenotype.
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Affiliation(s)
- Yimeng Xue
- 1Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,2Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Ding Nie
- 1Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Lin-Jian Wang
- 1Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,2Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Han-Cheng Qiu
- 1Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Long Ma
- 1Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Ming-Xin Dong
- 3Institute of Radiation Medicine, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin, China
| | - Wen-Jun Tu
- 1Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,3Institute of Radiation Medicine, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin, China
| | - Jizong Zhao
- 1Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,2Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China.,4China National Clinical Research Center for Neurological Diseases, Beijing, China.,5Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.,6Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China
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Liang C, Zou T, Zhang M, Fan W, Zhang T, Jiang Y, Cai Y, Chen F, Chen X, Sun Y, Zhao B, Wang Y, Cui L. MicroRNA-146a switches microglial phenotypes to resist the pathological processes and cognitive degradation of Alzheimer's disease. Theranostics 2021; 11:4103-4121. [PMID: 33754051 PMCID: PMC7977456 DOI: 10.7150/thno.53418] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 02/03/2021] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) is the most prevalent neurodegenerative disease and currently has no effective treatment. Mainstream research on the mechanisms and therapeutic targets of AD is focused on the two most important hallmarks, Aβ and Tau, but the results from clinical studies are not encouraging. Abnormal microglial polarization is a clear typical pathological feature in the progression of AD. Microglia can be neuroprotective by degrading and removing Aβ and Tau. However, under AD conditions, microglia transform into a pro-inflammatory phenotype that decreases the phagocytic activity of microglia, damages neurons and promotes the pathology of AD. We previously reported that a miR-146a polymorphism is associated with sporadic AD risk, and the nasal administration of miR-146a mimics reduced cognitive impairment and the main pathological features of AD. However, it is not clear by what mechanism miR-146a resists the pathological process of AD. In this study, we discovered that microglia-specific miR-146a overexpression reduced cognitive deficits in learning and memory, attenuated neuroinflammation, reduced Aβ levels, ameliorated plaque-associated neuritic pathology, and prevented neuronal loss in APP/PS1 transgenic mice. In addition, we found that miR-146a switched the microglial phenotype, reduced pro-inflammatory cytokines and enhanced phagocytic function to protect neurons in vitro and in vivo. Moreover, transcriptional analysis confirmed that miR-146a opposed the pathological process of AD mainly through neuroinflammation-related pathways. In summary, our results provide sufficient evidence for the mechanism by which miR-146a opposes AD and strengthen the conclusion that miR-146a is a promising target for AD and other microglia-related diseases.
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Lipoxin A4 regulates microglial M1/M2 polarization after cerebral ischemia-reperfusion injury via the Notch signaling pathway. Exp Neurol 2021; 339:113645. [PMID: 33600815 DOI: 10.1016/j.expneurol.2021.113645] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 01/30/2021] [Accepted: 02/12/2021] [Indexed: 11/23/2022]
Abstract
Microglia are rapidly activated after acute ischemic stroke, and the polarization of microglial is associated with the prognosis of acute ischemic stroke. Lipoxin A4 (LXA4), an anti-inflammatory agent, has a protective effect against ischemic stroke. However, the role of LXA4 on the polarization of microglial after acute ischemic stroke remains undetermined. We hypothesized that LXA4 may exert the neuroprotective effect though regulating the polarization of microglial. In this study, clinical features of acute ischemic stroke were simulated using a rat model of model of middle cerebral artery occlusion (MCAO) in vivo and the BV2 microglia oxygen-glucose deprivation/reoxygenation model (OGD/R) in vitro. The protective effects of LXA4 on cerebral ischemia-reperfusion injury were determined using TTC staining, HE staining, and TUNEL staining. The expression of targeted genes was assayed using quantitative real-time PCR (qRT-PCR), immunofluorescence, and western blot to investigated the regulation of LXA4 on microglia polarization after acute ischemic stroke. We found that LXA4 exerted protective effects on focal cerebral ischemia-reperfusion injury and reduced the expression of the pro-inflammatory cytokines IL-1β and TNF-α. Furthermore, LXA4 inhibited the expression of Notch-1, Hes1, iNOS and CD32 all of which are associated with the differentiation into M1 microglia. By contrast, LXA4 upregulated the expression of Hes5, Arg-1 and CD206 all of which are associated with M2 phenotype in microglia. In addition, blocking the Notch signaling pathway with the inhibitor DAPT significantly mitigated the effect of LXA4 on microglia differentiation. These data suggest that LXA4 may regulate the polarization of microglia after cerebral ischemia-reperfusion injury through the Notch signaling pathway.
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Alboni S, Benatti C, Colliva C, Radighieri G, Blom JMC, Brunello N, Tascedda F. Vortioxetine Prevents Lipopolysaccharide-Induced Memory Impairment Without Inhibiting the Initial Inflammatory Cascade. Front Pharmacol 2021; 11:603979. [PMID: 33613281 PMCID: PMC7890663 DOI: 10.3389/fphar.2020.603979] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 12/16/2020] [Indexed: 01/10/2023] Open
Abstract
Vortioxetine is a novel multimodal antidepressant that modulates a wide range of neurotransmitters throughout the brain. Preclinical and clinical studies have shown that vortioxetine exerts positive effects on different cognitive domains and neuroprotective effects. Considering the key role of microglial cells in brain plasticity and cognition, we aimed at investigating the effects of pretreatment with vortioxetine in modulating behavioral and molecular effects induced by an immune challenge: peripheral injection of lipopolysaccharide (LPS). To this purpose, C57BL/6J male mice were first exposed to a 28-day standard diet or vortioxetine-enriched diet, which was followed by an acute immune challenge with LPS. Sickness symptoms and depressive-like behaviors (anhedonia and memory impairment) were tested 6 and 24 h after exposure to LPS, respectively. Moreover, the expressions of markers of immune activation and M1/M2 markers of microglia polarization were measured in the dorsal and ventral parts of the hippocampus. The pretreatment with vortioxetine did not affect both LPS-induced sickness behavior and anhedonia but prevented the deficit in the recognition memory induced by the immune challenge. At the transcriptional level, chronic exposure to vortioxetine did not prevent LPS-induced upregulation of proinflammatory cytokines 6 h after the immune challenge but rather seemed to potentiate the immune response to the challenge also by affecting the levels of expression of markers of microglia M1 phenotype, like cluster of differentiation (CD)14 and CD86, in an area-dependent manner. However, at the same time point, LPS injection significantly increased the expression of the M2 polarization inducer, interleukin 4, only in the hippocampus of animals chronically exposed to vortioxetine. These results demonstrate that a chronic administration of vortioxetine specifically prevents LPS-induced memory impairment, without affecting acute sickness behavior and anhedonia, and suggest that hippocampal microglia may represent a cellular target of this novel antidepressant medication. Moreover, we provide a useful model to further explore the molecular mechanisms specifically underlying cognitive impairments following an immune challenge.
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Affiliation(s)
- S. Alboni
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Centre of Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - C. Benatti
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Centre of Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - C. Colliva
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - G. Radighieri
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - J. M. C. Blom
- Dept. of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Centre of Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - N. Brunello
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Centre of Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - F. Tascedda
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Centre of Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
- CIB, Consorzio Interuniversitario Biotecnologie, Trieste, Italy
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12
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Gubert C, Andrejew R, Figueiro F, Bergamin L, Kapczinski F, Magalhães PVDS, Battastini AMO. Lithium-induced neuroprotective activity in neuronal and microglial cells: A purinergic perspective. Psychiatry Res 2021; 295:113562. [PMID: 33213934 DOI: 10.1016/j.psychres.2020.113562] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/04/2020] [Indexed: 12/20/2022]
Abstract
Lithium is the mainstay of pharmacotherapy for treating bipolar disorder (BD). However, despite its wide use for over 60 years in the clinic, its mechanisms of action are not yet well defined. Elucidating lithium's mechanism of action will not only shed light on the pathophysiology of BD, but also potentially uncover new treatment targets. Previous studies suggest that the purinergic system may be involved in lithium's neuroprotective action; thus, the specific aim of this study is to better understand the neuroprotective action of lithium against ATP-induced cellular effect in both neuronal and microglial cellular lineages. We used PC12 neuronal and N9 microglial cells, evaluating cell death by cell counting and Annexin/PI cytometry assay, P2 × 7R immunocontent and ectonucleotidases activity, together with cytokine and nitrite assessment for microglial activity determination. Our results indicate that cells of different neural origins are responsive to ATP, in the sense of neuronal excitotoxicity and microglial switch into an activated M1-like phenotype respectively. Lithium, in turn, modulates the response in neuronal PC12 cells, preventing ATP-induced cell death. On the other hand, in N9 microglial cells, lithium was unable to prevent ATP-induced activation via P2 × 7R, indicating that lithium protective action against the effects of ATP more likely occurs in neurons rather than in microglia. Further studies are needed to better characterize the involvement of the purinergic system in the mechanism of action of lithium against neuronal death and microglial activation, in order to uncover new therapeutic adjunctive targets, such as antagonism of P2 × 7R, as potential approach for bipolar disorder treatment.
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Affiliation(s)
- Carolina Gubert
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, 90035-003 Porto Alegre, RS, Brazil.
| | - Roberta Andrejew
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, 90035-003 Porto Alegre, RS, Brazil
| | - Fabricio Figueiro
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, 90035-003 Porto Alegre, RS, Brazil
| | - Letícia Bergamin
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, 90035-003 Porto Alegre, RS, Brazil
| | - Flávio Kapczinski
- Department of Psychiatry and Behavioral Sciences, MacMaster University, Hamilton, Canada
| | - Pedro Vieira da Silva Magalhães
- Universidade Federal do Rio Grande do Sul, Hospital de Clínicas de Porto Alegre, Centro de Pesquisa Experimental, Graduate Program in Psychiatry and Behavioral Sciences, Brazil
| | - Ana Maria Oliveira Battastini
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, 90035-003 Porto Alegre, RS, Brazil
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13
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Synthesis, Molecular Modeling and Biological Evaluation of Metabolically Stable Analogues of the Endogenous Fatty Acid Amide Palmitoylethanolamide. Int J Mol Sci 2020; 21:ijms21239074. [PMID: 33260658 PMCID: PMC7730713 DOI: 10.3390/ijms21239074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/23/2020] [Accepted: 11/26/2020] [Indexed: 12/18/2022] Open
Abstract
Palmitoylethanolamide (PEA) belongs to the class of N-acylethanolamine and is an endogenous lipid potentially useful in a wide range of therapeutic areas; products containing PEA are licensed for use in humans as a nutraceutical, a food supplement, or food for medical purposes for its analgesic and anti-inflammatory properties demonstrating efficacy and tolerability. However, the exogenously administered PEA is rapidly inactivated; in this process, fatty acid amide hydrolase (FAAH) plays a key role both in hepatic metabolism and in intracellular degradation. So, the aim of the present study was the design and synthesis of PEA analogues that are more resistant to FAAH-mediated hydrolysis. A small library of PEA analogues was designed and tested by molecular docking and density functional theory calculations to find the more stable analogue. The computational investigation identified RePEA as the best candidate in terms of both synthetic accessibility and metabolic stability to FAAH-mediated hydrolysis. The selected compound was synthesized and assayed ex vivo to monitor FAAH-mediated hydrolysis and to confirm its anti-inflammatory properties. 1H-NMR spectroscopy performed on membrane samples containing FAAH in integral membrane protein demonstrated that RePEA is not processed by FAAH, in contrast with PEA. Moreover, RePEA retains PEA’s ability to inhibit LPS-induced cytokine release in both murine N9 microglial cells and human PMA-THP-1 cells.
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14
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Timmerman R, Burm SM, Bajramovic JJ. Tissue-specific features of microglial innate immune responses. Neurochem Int 2020; 142:104924. [PMID: 33248205 DOI: 10.1016/j.neuint.2020.104924] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/21/2020] [Accepted: 11/22/2020] [Indexed: 02/07/2023]
Abstract
As tissue-resident macrophages of the brain, microglia are increasingly considered as cellular targets for therapeutical intervention. Innate immune responses in particular have been implicated in central nervous system (CNS) infections, neuro-oncology, neuroinflammatory and neurodegenerative diseases. We here review the impact of 'nature and nurture' on microglial innate immune responses and summarize documented tissue-specific adaptations. Overall, such adaptations are associated with regulatory processes rather than with overt differences in the expressed repertoire of activating receptors of different tissue-resident macrophages. Microglial responses are characterized by slower kinetics, by a more persistent nature and by a differential usage of downstream enzymes and accessory receptors. We further consider factors like aging, previous exposure to inflammatory stimuli, and differences in the microenvironment that can modulate innate immune responses. The long-life span of microglia in the metabolically active CNS renders them susceptible to the phenomenon of 'inflammaging', and major challenges lie in the unraveling of the factors that underlie age-related alterations in microglial behavior.
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Affiliation(s)
- R Timmerman
- Alternatives Unit, Biomedical Primate Research Centre, Rijswijk, the Netherlands
| | - S M Burm
- Genmab, Utrecht, the Netherlands
| | - J J Bajramovic
- Alternatives Unit, Biomedical Primate Research Centre, Rijswijk, the Netherlands.
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15
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Quarta A, Berneman Z, Ponsaerts P. Neuroprotective modulation of microglia effector functions following priming with interleukin 4 and 13: current limitations in understanding their mode-of-action. Brain Behav Immun 2020; 88:856-866. [PMID: 32224056 DOI: 10.1016/j.bbi.2020.03.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/23/2020] [Accepted: 03/24/2020] [Indexed: 12/12/2022] Open
Abstract
In recent years the long-standing theory of microglia's properties for dual polarization towards a pro- or anti-inflammatory phenotype has been deeply challenged. Furthermore, the elucidation of microglia ontogenesis exposed intrinsic differences between microglia and peripheral myeloid cells, thereby further underscoring the need to re-evaluate microglia-specific activation behavior, especially within an inflamed central nervous system (CNS) environment. This review critically summarizes recent literature on the in vitro and in vivo response of murine microglia to the immune-modulatory cytokines interleukin 4 (IL4) and interleukin 13 (IL13), i.e. those driving the so-called anti-inflammatory phenotype. Here we highlight several pivotal factors that may influence experimental outcome and/or interpretation of in vitro and in vivo studies evaluating microglia's phenotypical and functional properties upon IL4/IL13 treatment. Finally, the current therapeutic relevance of IL4/IL13-induced microglia activation in both acute and chronic CNS disorders is discussed.
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Affiliation(s)
- Alessandra Quarta
- Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Zwi Berneman
- Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Peter Ponsaerts
- Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium.
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16
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Das R, Balmik AA, Chinnathambi S. Phagocytosis of full-length Tau oligomers by Actin-remodeling of activated microglia. J Neuroinflammation 2020; 17:10. [PMID: 31915009 PMCID: PMC6950897 DOI: 10.1186/s12974-019-1694-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/29/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Alzheimer's disease is associated with the accumulation of intracellular Tau tangles within neurons and extracellular amyloid-β plaques in the brain parenchyma, which altogether results in synaptic loss and neurodegeneration. Extracellular concentrations of oligomers and aggregated proteins initiate microglial activation and convert their state of synaptic surveillance into a destructive inflammatory state. Although Tau oligomers have fleeting nature, they were shown to mediate neurotoxicity and microglial pro-inflammation. Due to the instability of oligomers, in vitro experiments become challenging, and hence, the stability of the full-length Tau oligomers is a major concern. METHODS In this study, we have prepared and stabilized hTau40WT oligomers, which were purified by size-exclusion chromatography. The formation of the oligomers was confirmed by western blot, thioflavin-S, 8-anilinonaphthaalene-1-sulfonic acid fluorescence, and circular dichroism spectroscopy, which determine the intermolecular cross-β sheet structure and hydrophobicity. The efficiency of N9 microglial cells to phagocytose hTau40WT oligomer and subsequent microglial activation was studied by immunofluorescence microscopy with apotome. The one-way ANOVA was performed for the statistical analysis of fluorometric assay and microscopic analysis. RESULTS Full-length Tau oligomers were detected in heterogeneous globular structures ranging from 5 to 50 nm as observed by high-resolution transmission electron microscopy, which was further characterized by oligomer-specific A11 antibody. Immunocytochemistry studies for oligomer treatment were evidenced with A11+ Iba1high microglia, suggesting that the phagocytosis of extracellular Tau oligomers leads to microglial activation. Also, the microglia were observed with remodeled filopodia-like actin structures upon the exposure of oligomers and aggregated Tau. CONCLUSION The peri-membrane polymerization of actin filament and co-localization of Iba1 relate to the microglial movements for phagocytosis. Here, these findings suggest that microglia modified actin cytoskeleton for phagocytosis and rapid clearance of Tau oligomers in Alzheimer's disease condition.
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Affiliation(s)
- Rashmi Das
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Pune, 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Pune, 411008, India
| | - Abhishek Ankur Balmik
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Pune, 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Pune, 411008, India
| | - Subashchandrabose Chinnathambi
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Pune, 411008, India. .,Academy of Scientific and Innovative Research (AcSIR), Pune, 411008, India.
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17
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Du Q, Ge D, Mirshafiee V, Chen C, Li M, Xue C, Ma X, Sun B. Assessment of neurotoxicity induced by different-sized Stöber silica nanoparticles: induction of pyroptosis in microglia. NANOSCALE 2019; 11:12965-12972. [PMID: 31259344 DOI: 10.1039/c9nr03756j] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
With the wide application of Stöber silica nanoparticles and their ability to access the brain, it is crucial to evaluate their neurotoxicity. In this study, we used three in vitro model cells, i.e., N9, bEnd.3 and HT22 cells, representing microglia, microendothelial cells and neurons, respectively, to assess the neurotoxicity of Stöber silica nanoparticles with different sizes. We found that Stöber silica nanoparticles almost had no effect on the viability of bEnd.3 and HT22 cells. In contrast, they induced size-dependent toxicity in N9 cells, which represent the residential macrophages of the central nervous system. Further mechanistic study demonstrated that the toxicity in N9 cells was related to their surface silanol display. In addition, we demonstrated that Stöber silica nanoparticles induced the production of mitochondrial ROS, release of IL-1β, cleavage of GSDMD, and occurrence of pyroptosis in N9 cells. Features of pyroptosis were also observed in primary microglia and macrophage J774A.1. In conclusion, these findings were helpful for the safety consideration of Stöber silica nanoparticles considering their wide applications in our daily life.
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Affiliation(s)
- Qiqi Du
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China. and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China
| | - Dan Ge
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China. and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China
| | - Vahid Mirshafiee
- Center for Environmental Implications of Nanotechnology, California NanoSystems Institute, University of California Los Angeles, 570 Westwood Plaza, Los Angeles, California 90095, USA
| | - Chen Chen
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China. and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China
| | - Min Li
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China. and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China
| | - Changying Xue
- School of Life Science and Biotechnology, Dalian University of Technology, 116024, Dalian, China
| | - Xuehu Ma
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China. and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China
| | - Bingbing Sun
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China. and School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, 116024, Dalian, China
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18
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Yao K, Zu HB. Microglial polarization: novel therapeutic mechanism against Alzheimer's disease. Inflammopharmacology 2019; 28:95-110. [PMID: 31264132 DOI: 10.1007/s10787-019-00613-5] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/16/2019] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is the most prevalent neurodegenerative disease that results in progressive dementia, and exhibits high disability and fatality rates. Recent evidence has demonstrated that neuroinflammation is critical in the pathophysiological processes of AD, which is characterized by the activation of microglia and astrocytes. Under different stimuli, microglia are usually activated into two polarized states, termed the classical 'M1' phenotype and the alternative 'M2' phenotype. M1 microglia are considered to promote inflammatory injury in AD; in contrast, M2 microglia exert neuroprotective effects. Imbalanced microglial polarization, in the form of excessive activation of M1 microglia and dysfunction of M2 microglia, markedly promotes the development of AD. Furthermore, an increasing number of studies have shown that the transition of microglia from the M1 to M2 phenotype could potently alleviate pathological damage in AD. Hence, this article reviews the current knowledge regarding the role of microglial M1/M2 polarization in the pathophysiology of AD. In addition, we summarize several approaches that protect against AD by altering the polarization states of microglia. This review aims to contribute to a better understanding of the pathogenesis of AD and, moreover, to explore the potential of novel drugs for the treatment of AD in the future.
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Affiliation(s)
- Kai Yao
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China
| | - Heng-Bing Zu
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China.
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19
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Manchikalapudi AL, Chilakala RR, Kalia K, Sunkaria A. Evaluating the Role of Microglial Cells in Clearance of Aβ from Alzheimer's Brain. ACS Chem Neurosci 2019; 10:1149-1156. [PMID: 30609357 DOI: 10.1021/acschemneuro.8b00627] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ever increasing incidence of Alzheimer's diseases (AD) has been reported all over the globe, and practically no drug is currently available for its treatment. In the past 15 years, not a single drug came out of clinical trials. The researchers have yet to discover a drug that could specifically target AD; in fact, the drugs that are about to launch in the global market either belong to natural compounds or are already approved drugs targeting other diseases. So, we need to shift our focus on finding novel targets which are more specific and could either detect or inhibit the disease progression at a very early stage. Microglia are the only resident innate immune cells of the brain that are originated from erythromyeloid progenitors. They migrate to the brain during early embryonic development, although their number is less (∼5 to 10%), but they could act as guardians of the brain. It has been shown that the extracellular deposits of Aβ are continuously phagocytosed by microglia in healthy individuals, but this ability would decrease with age and lead to development of AD. In this review, we have explored the possibility of whether microglial cells could be utilized as an early predictor of the AD progression. Here, we discuss the innate immune response of microglial cells, the factors affecting microglia response, microglial receptors to which Aβ could bind, and microglial phenotype markers. Last, we conclude with a list of available AD therapeutics along with their mechanism.
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Affiliation(s)
| | - Rajasekhar Reddy Chilakala
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Ahmedabad, Gujarat, India
| | - Kiran Kalia
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Ahmedabad, Gujarat, India
| | - Aditya Sunkaria
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Ahmedabad, Gujarat, India
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20
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Cheng Z, Yang Y, Duan F, Lou B, Zeng J, Huang Y, Luo Y, Lin X. Inhibition of Notch1 Signaling Alleviates Endotoxin-Induced Inflammation Through Modulating Retinal Microglia Polarization. Front Immunol 2019; 10:389. [PMID: 30930891 PMCID: PMC6423918 DOI: 10.3389/fimmu.2019.00389] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/14/2019] [Indexed: 12/17/2022] Open
Abstract
Microglial cells are resident immune cells and play an important role in various cerebral and retinal inflammatory diseases. Notch1 signaling is involved in the microglia polarization and the control of cerebral inflammatory reactions. However, its role in endotoxin-induced uveitis (EIU) remains unknown. This study aimed to investigate the role of Notch1 signaling on retinal microglia polarization and inflammation in the cultured retinal microglial cells and EIU rat model. We found that Notch1 signaling blockade with N-[N-(3, 5-difluorophenacetyl)-1-alany1-S-phenyglycine t-butyl ester (DAPT) shifted retinal microglia phenotype from pro-inflammatory M1 phenotype (COX2+ and iNOS+) to anti-inflammatory M2 phenotype (Arg-1+) and reduced the release of pro-inflammatory cytokines both in vivo and in vitro. Moreover, DAPT treatment contributed to prevent retinal ganglion cells from apoptosis, reduce the intraocular infiltrating cells, and attenuate the impairment of retinal function. Taken together, these results suggest that inhibition of Notch1 signaling could alleviate the inflammatory response in EIU rat mainly through regulating the polarization of retinal microglia. Therefore, Notch1 signaling might be a promising therapeutic target in the treatment of ocular inflammatory diseases.
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Affiliation(s)
- Zhixing Cheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Yao Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Fang Duan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Bingsheng Lou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Jieting Zeng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Yanqiao Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Yan Luo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Xiaofeng Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
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21
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Imbalance of Microglial TLR4/TREM2 in LPS-Treated APP/PS1 Transgenic Mice: A Potential Link Between Alzheimer's Disease and Systemic Inflammation. Neurochem Res 2019; 44:1138-1151. [PMID: 30756214 DOI: 10.1007/s11064-019-02748-x] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/01/2019] [Accepted: 02/01/2019] [Indexed: 02/07/2023]
Abstract
Clinically, superimposed systemic inflammation generally has significant deleterious effects on the Alzheimer's disease (AD) progression. However, the related molecular mechanisms remain poorly understood. Microglial toll-like receptor 4 (TLR4) and triggering receptor expressed on myeloid cells 2 (TREM2) are two key regulators of inflammation that may play an essential role in this complex pathophysiological process. In this study, intraperitoneal injection of lipopolysaccharide (LPS) into APP/PS1 transgenic AD model was used to mimic systemic inflammation in the development of AD. Initial results from the cortex showed that compared with wild-type mice, APP/PS1 mice exhibited elevated gene and protein expression levels of both TLR4 and TREM2 with different degree. Interestingly, after LPS treatment, TLR4 expression was persistently up-regulated, while TREM2 expression was significantly down-regulated in APP/PS1 mice, suggesting that the negative regulatory effect of TREM2 on inflammation might be suppressed by LPS-induced hyperactive TLR4. This imbalance of TLR4/TREM2 contributed to microglial over-activation, followed by increased neuronal apoptosis in the cortex of APP/PS1 mice; these changes did not alter the expression level of Aβ1-42. Similar alterations were observed in our in vitro experiment with β-amyloid1-42 (Aβ1-42)-treated N9 microglia. Further, Morris water maze (MWM) testing data indicated that LPS administration acutely aggravated cognitive impairment in APP/PS1 mice, suggesting that the addition of systemic inflammation can potentially accelerate the progression of AD. Collectively, we conclude that an imbalance of TLR4/TREM2 may be a potential link between AD and systemic inflammation. TREM2 can serve as a potential therapeutic target for treating systemic inflammation in AD progression.
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Wu J, Ding DH, Li QQ, Wang XY, Sun YY, Li LJ. Lipoxin A4 Regulates Lipopolysaccharide-Induced BV2 Microglial Activation and Differentiation via the Notch Signaling Pathway. Front Cell Neurosci 2019; 13:19. [PMID: 30778288 PMCID: PMC6369213 DOI: 10.3389/fncel.2019.00019] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 01/16/2019] [Indexed: 12/16/2022] Open
Abstract
Inflammatory responses contribute to the pathogenesis of various neurological diseases, and microglia plays an important role in the process. Activated microglia can differentiate into the pro-inflammatory, tissue-damaging M1 phenotype or the anti-inflammatory, tissue-repairing M2 phenotype. Regulating microglia differentiation, hence limiting a harmful response, might help improve the prognosis of inflammation-related nervous system diseases. The present study aimed 1. to observe the anti-inflammatory effect of lipoxin A4 (LXA4) on the inflammatory response associated to lipopolysaccharide (LPS)-induced microglia activation, 2. to clarify that LXA4 modulates the activation and differentiation of microglia induced by LPS stimulation, 3. to determine whether LXA4 regulates the activation and differentiation of microglia through the Notch signaling pathway, 4. to provide a foundation for the use of LXA4 for the treatment of inflammatory related neurological diseases. To construct a model of cellular inflammation, immortalized murine BV2 microglia cells were provided 200 ng/ml LPS. To measure the mRNA and protein levels of inflammatory factors (interleukin [IL]-1β, IL-10, and tumor necrosis factor [TNF]-α) and M1 and M2 microglia markers (inducible nitric oxide synthase [iNOS], cluster of differentiation [CD]32, arginase [Arg]1, and CD206), we performed quantitative reverse transcription polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA), immunofluorescence, or flow cytometry. To determine the mRNA and protein levels of Notch signaling components (Notch1, Hes1, and Hes5), we performed qRT-PCR and western blot. LXA4 inhibits the expression of Notch1 and Hes1 associated with M1 type microglial differentiation and decreases the M1 type microglia marker iNOS and related inflammatory factors IL-1β and TNF-α. Moreover, LXA4 upregulates the expression of the M2-associated Hes5, as well as the expression of the M2 microglia marker Arg1 and the associated inflammatory factor IL-10. These effects are blocked by the administration of the γ-secretase inhibitor DAPT, a specific blocker of the Notch signaling pathway. LXA4 inhibits the microglia activation induced by LPS and the differentiation into M1 type with pro-inflammatory effect, while promoting the differentiation to M2 type with anti-inflammatory effect. LXA4 downregulates the inflammatory mediators IL-1β, TNF-α, and iNOS, while upregulating the anti-inflammatory mediator IL-10, which acts through the Notch signaling pathway.
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Affiliation(s)
- Jun Wu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Dan-Hua Ding
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Qian-Qian Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xin-Yu Wang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yu-Ying Sun
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Lan-Jun Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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23
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Shi H, Wang XL, Quan HF, Yan L, Pei XY, Wang R, Peng XD. Effects of Betaine on LPS-Stimulated Activation of Microglial M1/M2 Phenotypes by Suppressing TLR4/NF-κB Pathways in N9 Cells. Molecules 2019; 24:molecules24020367. [PMID: 30669620 PMCID: PMC6359206 DOI: 10.3390/molecules24020367] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 12/28/2018] [Accepted: 01/18/2019] [Indexed: 11/16/2022] Open
Abstract
Microglia mediate multiple facets of neuroinflammation. They can be phenotypically divided into a classical phenotype (pro-inflammatory, M1) or an alternative phenotype (anti-inflammatory, M2) with different physiological characteristics and biological functions in the inflammatory process. Betaine has been shown to exert anti-inflammatory effects. In this study, we aimed to verify the anti-inflammatory effects of betaine and elucidate its possible molecular mechanisms of action in vitro. Lipopolysaccharide (LPS)-activated microglial cells were used as an inflammatory model to study the anti-inflammatory efficacy of betaine and explore its mechanism of regulating microglial polarisation by investigating the morphological changes and associated inflammatory changes. Cytokine and inflammatory mediator expression was also measured by ELISA, flow cytometry, immunofluorescence, and western blot analysis. Toll-like receptor (TLR)-myeloid differentiation factor 88 (Myd88)-nuclear factor-kappa B (NF-κB) p65, p-NF-κB p65, IκB, p-IκB, IκB kinase (IKK), and p-IKK expression was determined by western blot analysis. Betaine significantly mitigated the production of pro-inflammatory cytokines and increased the release of anti-inflammatory cytokines. It promoted the conversion of the microglia from M1 to M2 phenotype by decreasing the expression of inducible nitric oxide synthase and CD16/32 and by increasing that of CD206 and arginase-1. Betaine treatment inhibited the TLR4/NF-κB pathways by attenuating the expression of TLR4-Myd88 and blocking the phosphorylation of IκB and IKK. In conclusion, betaine could significantly alleviate LPS-induced inflammation by regulating the polarisation of microglial phenotype; thus, it might be an effective therapeutic agent for neurological disorders.
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Affiliation(s)
- Hui Shi
- Department of Pharmacology, Ningxia Medical University, Yinchuan 750004, China.
| | - Xiao-Long Wang
- Department of Pharmacology, Ningxia Medical University, Yinchuan 750004, China.
| | - Hong-Feng Quan
- Department of Pharmacology, Ningxia Medical University, Yinchuan 750004, China.
| | - Lin Yan
- Functional Experiment Center, School of Basic Medicine, Ningxia Medical University, Yinchuan 750004, China.
| | - Xiu-Ying Pei
- Laboratory in Fertility Preservation and Maintenance of Ministry of Education, Ningxia Medical University, Yinchuan 750004, China.
| | - Rui Wang
- Department of Pharmacology, Ningxia Medical University, Yinchuan 750004, China.
- Laboratory in Fertility Preservation and Maintenance of Ministry of Education, Ningxia Medical University, Yinchuan 750004, China.
| | - Xiao-Dong Peng
- Department of Pharmacology, Ningxia Medical University, Yinchuan 750004, China.
- Functional Experiment Center, School of Basic Medicine, Ningxia Medical University, Yinchuan 750004, China.
- Laboratory in Fertility Preservation and Maintenance of Ministry of Education, Ningxia Medical University, Yinchuan 750004, China.
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24
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An introduction to innate immunity in the central nervous system. ROLE OF INFLAMMATION IN ENVIRONMENTAL NEUROTOXICITY 2019. [DOI: 10.1016/bs.ant.2018.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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25
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Cheray M, Joseph B. Epigenetics Control Microglia Plasticity. Front Cell Neurosci 2018; 12:243. [PMID: 30123114 PMCID: PMC6085560 DOI: 10.3389/fncel.2018.00243] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/18/2018] [Indexed: 01/31/2023] Open
Abstract
Microglia, resident immune cells of the central nervous system, fulfill multiple functions in the brain throughout life. These microglial functions range from participation in innate and adaptive immune responses, involvement in the development of the brain and its homeostasis maintenance, to contribution to degenerative, traumatic, and proliferative diseases; and take place in the developing, the aging, the healthy, or the diseased brain. Thus, an impressive level of cellular plasticity, appears as a requirement for the pleiotropic biological functions of microglia. Epigenetic changes, including histone modifications or DNA methylation as well as microRNA expression, are important modifiers of gene expression, and have been involved in cell phenotype regulation and reprogramming and are therefore part of the mechanisms regulating cellular plasticity. Here, we review and discuss the epigenetic mechanisms, which are emerging as contributors to this microglial cellular plasticity and thereby can constitute interesting targets to modulate microglia associated brain diseases, including developmental diseases, neurodegenerative diseases as well as cancer.
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Affiliation(s)
- Mathilde Cheray
- Toxicology Unit, Institute of Environmental Medicine, Karolinska Institutet, Solna, Sweden
| | - Bertrand Joseph
- Toxicology Unit, Institute of Environmental Medicine, Karolinska Institutet, Solna, Sweden
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26
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Ma P, Han H, Qin H. Reply to: "Studies of macrophage therapy for cirrhosis - From mice to men". J Hepatol 2018; 68:1091-1093. [PMID: 29317296 DOI: 10.1016/j.jhep.2017.12.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 12/29/2017] [Indexed: 12/04/2022]
Affiliation(s)
- Pengfei Ma
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China; Department of Hepatobiliary Surgery, PLA Navy General Hospital, Beijing, China
| | - Hua Han
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China
| | - Hongyan Qin
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China.
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27
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Eren E, Tufekci KU, Isci KB, Tastan B, Genc K, Genc S. Sulforaphane Inhibits Lipopolysaccharide-Induced Inflammation, Cytotoxicity, Oxidative Stress, and miR-155 Expression and Switches to Mox Phenotype through Activating Extracellular Signal-Regulated Kinase 1/2-Nuclear Factor Erythroid 2-Related Factor 2/Antioxidant Response Element Pathway in Murine Microglial Cells. Front Immunol 2018; 9:36. [PMID: 29410668 PMCID: PMC5787131 DOI: 10.3389/fimmu.2018.00036] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 01/05/2018] [Indexed: 12/18/2022] Open
Abstract
Sulforaphane (SFN) is a natural product with cytoprotective, anti-inflammatory, and antioxidant effects. In this study, we evaluated the mechanisms of its effects on lipopolysaccharide (LPS)-induced cell death, inflammation, oxidative stress, and polarization in murine microglia. We found that SFN protects N9 microglial cells upon LPS-induced cell death and suppresses LPS-induced levels of secreted pro-inflammatory cytokines, tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6. SFN is also a potent inducer of redox sensitive transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), which is responsible for the transcription of antioxidant, cytoprotective, and anti-inflammatory genes. SFN induced translocation of Nrf2 to the nucleus via extracellular signal-regulated kinase 1/2 (ERK1/2) pathway activation. siRNA-mediated knockdown study showed that the effects of SFN on LPS-induced reactive oxygen species, reactive nitrogen species, and pro-inflammatory cytokine production and cell death are partly Nrf2 dependent. Mox phenotype is a novel microglial phenotype that has roles in oxidative stress responses. Our results suggested that SFN induced the Mox phenotype in murine microglia through Nrf2 pathway. SFN also alleviated LPS-induced expression of inflammatory microRNA, miR-155. Finally, SFN inhibits microglia-mediated neurotoxicity as demonstrated by conditioned medium and co-culture experiments. In conclusion, SFN exerts protective effects on microglia and modulates the microglial activation state.
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Affiliation(s)
- Erden Eren
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, Izmir, Turkey.,Department of Neuroscience, Health Science Institute, Dokuz Eylül University, Izmir, Turkey
| | - Kemal Ugur Tufekci
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, Izmir, Turkey.,Department of Neuroscience, Health Science Institute, Dokuz Eylül University, Izmir, Turkey
| | - Kamer Burak Isci
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, Izmir, Turkey.,Department of Neuroscience, Health Science Institute, Dokuz Eylül University, Izmir, Turkey
| | - Bora Tastan
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, Izmir, Turkey.,Department of Neuroscience, Health Science Institute, Dokuz Eylül University, Izmir, Turkey
| | - Kursad Genc
- Department of Neuroscience, Health Science Institute, Dokuz Eylül University, Izmir, Turkey
| | - Sermin Genc
- Izmir International Biomedicine and Genome Institute, Dokuz Eylül University, Izmir, Turkey.,Department of Neuroscience, Health Science Institute, Dokuz Eylül University, Izmir, Turkey
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28
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Ma PF, Gao CC, Yi J, Zhao JL, Liang SQ, Zhao Y, Ye YC, Bai J, Zheng QJ, Dou KF, Han H, Qin HY. Cytotherapy with M1-polarized macrophages ameliorates liver fibrosis by modulating immune microenvironment in mice. J Hepatol 2017; 67:770-779. [PMID: 28596109 DOI: 10.1016/j.jhep.2017.05.022] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Revised: 04/26/2017] [Accepted: 05/22/2017] [Indexed: 01/07/2023]
Abstract
BACKGROUND & AIMS Macrophages play vital roles in chronic liver injury, and have been tested as a tool for cytotherapy in liver fibrosis. However, macrophages possess ontogenic and functional heterogeneities. Some subsets are pro-fibrotic, whereas others are anti-fibrotic. This study aimed to clarify which macrophage subset is efficient for cytotherapy in liver fibrosis and to elucidate the underlying mechanisms. METHODS Liver fibrosis was induced in mice by carbon tetrachloride injection or bile duct ligation. Bone-marrow-derived macrophages (BMDMs) were polarized into M0, M1, or M2 macrophages, respectively. BMDMs were infused into mice through the tail vein at different stages of fibrogenesis. Fibrosis progression, hepatic cell populations, and related molecular changes were evaluated. RESULTS Both M0 and M1 BMDMs significantly ameliorated liver fibrosis, but M1 exhibited stronger therapeutic effects than M0. M2 macrophages were not effective on liver fibrosis. M1 macrophages reduced the number and activation of hepatic stellate cells (HSCs), which could be attributed at least partly to increased HSC apoptosis. M1 macrophages enhanced the recruitment of endogenous macrophages into fibrotic liver, which displayed the phenotype of Ly6Clo restorative macrophages and produced matrix metalloproteinases (MMPs) and hepatic growth factor (HGF) to enhance collagen degradation and hepatocyte proliferation, respectively. M1 macrophages also increased the number of total and activated natural killer (NK) cells in the fibrotic liver, which released TNF-related apoptosis-inducing ligand (TRAIL), inducing HSC apoptosis. CONCLUSIONS M1 macrophages, which modulate the immune microenvironment to recruit and modify the activation of endogenous macrophages and NK cells, are effective for cytotherapy in experimental liver fibrosis. Lay summary: M1 Bone marrow-derived macrophages (BMDMs) exhibit a stronger therapeutic effect by modulating the hepatic microenvironment to recruit and modify the activation of endogenous macrophages and natural killer (NK) cells, which likely lead to hepatic stellate cells (HSCs) apoptosis and hampered fibrogenesis.
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Affiliation(s)
- Peng-Fei Ma
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China; State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China
| | - Chun-Chen Gao
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China
| | - Jing Yi
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China
| | - Jun-Long Zhao
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China
| | - Shi-Qian Liang
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China
| | - Yang Zhao
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China
| | - Yu-Chen Ye
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China; State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China
| | - Jian Bai
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China
| | - Qi-Jun Zheng
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China
| | - Ke-Feng Dou
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
| | - Hua Han
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China; State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China.
| | - Hong-Yan Qin
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an 710032, China.
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29
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Is macrophage polarization important in rheumatoid arthritis? Int Immunopharmacol 2017; 50:345-352. [PMID: 28750350 DOI: 10.1016/j.intimp.2017.07.019] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/16/2017] [Accepted: 07/19/2017] [Indexed: 12/15/2022]
Abstract
Macrophages are myeloid immune cells which are strategically positioned throughout the body, where they engulf and degrade debris, dead cells, and foreign substances, and coordinating the inflammatory processes. Macrophages can be divided into two extreme subsets, classical activation (M1), and alternatively activation (M2). The symptoms and signs of rheumatoid arthritis (RA) would exacerbate with the increase in pro-inflammatory cytokines, whereas anti-inflammatory cytokines will alleviate the symptoms and signs of RA. This review, mainly discusses the effects of Notch, JNK and ERK signaling pathways on the regulation of macrophage polarization, and the effects of pro-inflammatory factors and/or anti-inflammatory cytokines produced by polarized macrophages in RA. Also, we will make an attempt to find out the importance of macrophage polarization in RA treatment as a drug target.
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30
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Zhao SC, Ma LS, Chu ZH, Xu H, Wu WQ, Liu F. Regulation of microglial activation in stroke. Acta Pharmacol Sin 2017; 38:445-458. [PMID: 28260801 DOI: 10.1038/aps.2016.162] [Citation(s) in RCA: 253] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 11/06/2016] [Indexed: 12/16/2022] Open
Abstract
When ischemic stroke occurs, oxygen and energy depletion triggers a cascade of events, including inflammatory responses, glutamate excitotoxicity, oxidative stress, and apoptosis that result in a profound brain injury. The inflammatory response contributes to secondary neuronal damage, which exerts a substantial impact on both acute ischemic injury and the chronic recovery of the brain function. Microglia are the resident immune cells in the brain that constantly monitor brain microenvironment under normal conditions. Once ischemia occurs, microglia are activated to produce both detrimental and neuroprotective mediators, and the balance of the two counteracting mediators determines the fate of injured neurons. The activation of microglia is defined as either classic (M1) or alternative (M2): M1 microglia secrete pro-inflammatory cytokines (TNFα, IL-23, IL-1β, IL-12, etc) and exacerbate neuronal injury, whereas the M2 phenotype promotes anti-inflammatory responses that are reparative. It has important translational value to regulate M1/M2 microglial activation to minimize the detrimental effects and/or maximize the protective role. Here, we discuss various regulators of microglia/macrophage activation and the interaction between microglia and neurons in the context of ischemic stroke.
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31
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Palmieri EM, Menga A, Lebrun A, Hooper DC, Butterfield DA, Mazzone M, Castegna A. Blockade of Glutamine Synthetase Enhances Inflammatory Response in Microglial Cells. Antioxid Redox Signal 2017; 26:351-363. [PMID: 27758118 PMCID: PMC5346956 DOI: 10.1089/ars.2016.6715] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AIMS Microglial cells are brain-resident macrophages engaged in surveillance and maintained in a constant state of relative inactivity. However, their involvement in autoimmune diseases indicates that in pathological conditions microglia gain an inflammatory phenotype. The mechanisms underlying this change in the microglial phenotype are still unclear. Since metabolism is an important modulator of immune cell function, we focused our attention on glutamine synthetase (GS), a modulator of the response to lipopolysaccharide (LPS) activation in other cell types, which is expressed by microglia. RESULTS GS inhibition enhances release of inflammatory mediators of LPS-activated microglia in vitro, leading to perturbation of the redox balance and decreased viability of cocultured neurons. GS inhibition also decreases insulin-mediated glucose uptake in microglia. In vivo, microglia-specific GS ablation enhances expression of inflammatory markers upon LPS treatment. In the spinal cords from experimental autoimmune encephalomyelitis (EAE), GS expression levels and glutamine/glutamate ratios are reduced. INNOVATION Recently, metabolism has been highlighted as mediator of immune cell function through the discovery of mechanisms that (behind these metabolic changes) modulate the inflammatory response. The present study shows for the first time a metabolic mechanism mediating microglial response to a proinflammatory stimulus, pointing to GS activity as a master modulator of immune cell function and thus unraveling a potential therapeutic target. CONCLUSIONS Our study highlights a new role of GS in modulating immune response in microglia, providing insights into the pathogenic mechanisms associated with inflammation and new strategies of therapeutic intervention. Antioxid. Redox Signal. 26, 351-363.
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Affiliation(s)
- Erika M Palmieri
- 1 Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari , Bari, Italy
| | - Alessio Menga
- 2 National Cancer Research Center, Istituto Tumori 'Giovanni Paolo II,' Bari, Italy
| | - Aurore Lebrun
- 3 Department of Cancer Biology, Thomas Jefferson University , Philadelphia, Pennsylvania.,4 Department of Neurological Surgery, Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Douglas C Hooper
- 3 Department of Cancer Biology, Thomas Jefferson University , Philadelphia, Pennsylvania.,4 Department of Neurological Surgery, Thomas Jefferson University , Philadelphia, Pennsylvania
| | - D Allan Butterfield
- 5 Department of Chemistry, University of Kentucky , Lexington, Kentucky.,6 Sanders-Brown Center on Aging, University of Kentucky , Lexington, Kentucky
| | - Massimiliano Mazzone
- 7 Laboratory of Tumor Inflammation and Angiogenesis, Department of Oncology, University of Leuven , Leuven, Belgium .,8 Laboratory of Tumor Inflammation and Angiogenesis, Vesalius Research Center, VIB, Leuven, Belgium
| | - Alessandra Castegna
- 1 Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari , Bari, Italy .,2 National Cancer Research Center, Istituto Tumori 'Giovanni Paolo II,' Bari, Italy
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32
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Exploring New Inflammatory Biomarkers and Pathways during LPS-Induced M1 Polarization. Mediators Inflamm 2016; 2016:6986175. [PMID: 28096568 PMCID: PMC5209629 DOI: 10.1155/2016/6986175] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 10/18/2016] [Accepted: 11/07/2016] [Indexed: 12/25/2022] Open
Abstract
Identification of mediators triggering microglia activation and transference of noncoding microRNA (miRNA) into exosomes are critical to dissect the mechanisms underlying neurodegeneration. We used lipopolysaccharide- (LPS-) induced N9 microglia activation to explore new biomarkers/signaling pathways and to identify inflammatory miRNA (inflamma-miR) in cells and their derived exosomes. Upregulation of iNOS and MHC-II (M1-markers) and downregulation of arginase 1, FIZZ1 (M2-markers), and CX3CR1 (M0/M2 polarization) confirmed the switch of N9 LPS-treated cells into the M1 phenotype, as described for macrophages/microglia. Cells showed increased proliferation, activated TLR4/TLR2/NF-κB pathway, and enhanced phagocytosis, further corroborated by upregulated MFG-E8. We found NLRP3-inflammasome activation in these cells, probably accounting for the increased extracellular content of the cytokine HMGB1 and of the MMP-9 we have observed. We demonstrate for the first time that the inflamma-miR profiling (upregulated miR-155 and miR-146a plus downregulated miR-124) in M1 polarized N9 cells, noticed by others in activated macrophages/microglia, was replicated in their derived exosomes, likely regulating the inflammatory response of recipient cells and dissemination processes. Data show that LPS-treated N9 cells behave like M1 polarized microglia/macrophages, while providing new targets for drug discovery. In particular, the study yields novel insights into the exosomal circulating miRNA during neuroinflammation important for emerging therapeutic approaches targeting microglia activation.
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33
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Huang M, Wan Y, Mao L, He QW, Xia YP, Li M, Li YN, Jin HJ, Hu B. Inhibiting the Migration of M1 Microglia at Hyperacute Period Could Improve Outcome of tMCAO Rats. CNS Neurosci Ther 2016; 23:222-232. [PMID: 27991729 DOI: 10.1111/cns.12665] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 11/14/2016] [Accepted: 11/14/2016] [Indexed: 12/29/2022] Open
Abstract
AIM To study whether inhibiting microglia migration to the ischemic boundary zone (IBZ) at the early phase could improve neurological outcomes after stroke. METHODS The transient middle cerebral artery occlusion (tMCAO) was induced in adult male Sprague-Dawley rats. AMD3100, a highly selective CXC-chemokine receptor 4 (CXCR4) antagonist, was used to inhibit microglia migration. Microglia was evaluated by immunofluorescence in vivo, and their migration was tested by transwell assay in vitro. Expressions of cytokines were detected by real-time PCR. Infarct volume was determined by triphenyltetrazolium chloride (TTC) staining. Functional recovery of tMCAO rats was evaluated by behavior tests. RESULTS M1 microglia in the IBZ was rapidly increased within 3 days after tMCAO, accompanied with enhanced expression of CXCR4. Chemokine CXC motif chemokine ligand 12 (CXCL12) was also increased in the IBZ. And AMD3100 could obviously decline M1 microglia migration induced by CXCL12 and secretion of related inflammatory cytokines in the IBZ after stroke. This was accompanied by significant attenuated infarct volume and improved neurological outcomes. CONCLUSION This study confirms the protective efficacy of inhibiting microglia migration at the hyperacute phase as a therapeutic strategy for ischemic stroke in tMCAO model of rats, and its therapeutic time window could last for 24 h after cerebral ischemia reperfusion.
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Affiliation(s)
- Ming Huang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Neurology, Institute of Neural Regeneration and Repair, The First Hospital of Yichang, Three Gorges University College of Medicine, Yichang, China
| | - Yan Wan
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ling Mao
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Quan-Wei He
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuan-Peng Xia
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Man Li
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ya-Nan Li
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hui-Juan Jin
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bo Hu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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34
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Cai Z, Zhao B, Deng Y, Shangguan S, Zhou F, Zhou W, Li X, Li Y, Chen G. Notch signaling in cerebrovascular diseases (Review). Mol Med Rep 2016; 14:2883-98. [PMID: 27574001 PMCID: PMC5042775 DOI: 10.3892/mmr.2016.5641] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 07/22/2016] [Indexed: 12/30/2022] Open
Abstract
The Notch signaling pathway is a crucial regulator of numerous fundamental cellular processes. Increasing evidence suggests that Notch signaling is involved in inflammation and oxidative stress, and thus in the progress of cerebrovascular diseases. In addition, Notch signaling in cerebrovascular diseases is associated with apoptosis, angiogenesis and the function of blood-brain barrier. Despite the contradictory results obtained to date as to whether Notch signaling is harmful or beneficial, the regulation of Notch signaling may provide a novel strategy for the treatment of cerebrovascular diseases.
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Affiliation(s)
- Zhiyou Cai
- Department of Neurology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Bin Zhao
- Department of Neurology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Yanqing Deng
- Department of Neurology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Shouqin Shangguan
- Department of Neurology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Faming Zhou
- Department of Neurology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Wenqing Zhou
- Department of Neurology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Xiaoli Li
- Department of Neurology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Yanfeng Li
- Department of Neurology, Peking Union Medical College Hospital, Beijing 100730, P.R. China
| | - Guanghui Chen
- Department of Neurology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
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Myeloid-Specific Blockade of Notch Signaling Attenuates Choroidal Neovascularization through Compromised Macrophage Infiltration and Polarization in Mice. Sci Rep 2016; 6:28617. [PMID: 27339903 PMCID: PMC4919651 DOI: 10.1038/srep28617] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 06/06/2016] [Indexed: 11/09/2022] Open
Abstract
Macrophages have been recognized as an important inflammatory component in choroidal neovascularization (CNV). However, it is unclear how these cells are activated and polarized, how they affect angiogenesis and what the underlining mechanisms are during CNV. Notch signaling has been implicated in macrophage activation. Previously we have shown that inducible disruption of RBP-J, the critical transcription factor of Notch signaling, in adult mice results in enhanced CNV, but it is unclear what is the role of macrophage-specific Notch signaling in the development of CNV. In the current study, by using the myeloid specific RBP-J knockout mouse model combined with the laser-induced CNV model, we show that disruption of Notch signaling in macrophages displayed attenuated CNV growth, reduced macrophage infiltration and activation, and alleviated angiogenic response after laser induction. The inhibition of CNV occurred with reduced expression of VEGF and TNF-α in infiltrating inflammatory macrophages in myeloid specific RBP-J knockout mice. These changes might result in direct inhibition of EC lumen formation, as shown in an in vitro study. Therefore, clinical intervention of Notch signaling in CNV needs to pinpoint myeloid lineage to avoid the counteractive effects of global inhibition.
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36
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Meireles M, Marques C, Norberto S, Santos P, Fernandes I, Mateus N, Faria A, Calhau C. Anthocyanin effects on microglia M1/M2 phenotype: Consequence on neuronal fractalkine expression. Behav Brain Res 2016; 305:223-8. [DOI: 10.1016/j.bbr.2016.03.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/29/2016] [Accepted: 03/05/2016] [Indexed: 02/03/2023]
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Scutellarin as a Potential Therapeutic Agent for Microglia-Mediated Neuroinflammation in Cerebral Ischemia. Neuromolecular Med 2016; 18:264-73. [PMID: 27103430 DOI: 10.1007/s12017-016-8394-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 04/04/2016] [Indexed: 12/26/2022]
Abstract
The cerebral ischemia is one of the most common diseases in the central nervous system that causes progressive disability or even death. In this connection, the inflammatory response mediated by the activated microglia is believed to play a central role in this pathogenesis. In the event of brain injury, activated microglia can clear the cellular debris and invading pathogens, release neurotrophic factors, etc., but in chronic activation microglia may cause neuronal death through the release of excessive inflammatory mediators. Therefore, suppression of microglial over-reaction and microglia-mediated neuroinflammation is deemed to be a therapeutic strategy of choice for cerebral ischemic damage. In the search for potential herbal extracts that are endowed with the property in suppressing the microglial activation and amelioration of neuroinflammation, attention has recently been drawn to scutellarin, a Chinese herbal extract. Here, we review the roles of activated microglia and the effects of scutellarin on activated microglia in pathological conditions especially in ischemic stroke. We have further extended the investigation with special reference to the effects of scutellarin on Notch signaling, one of the several signaling pathways known to be involved in microglial activation. Furthermore, in light of our recent experimental evidence that activated microglia can regulate astrogliosis, an interglial "cross-talk" that was amplified by scutellarin, it is suggested that in designing of a more effective therapeutic strategy for clinical management of cerebral ischemia both glial types should be considered collectively.
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Zhang F, Nance E, Alnasser Y, Kannan R, Kannan S. Microglial migration and interactions with dendrimer nanoparticles are altered in the presence of neuroinflammation. J Neuroinflammation 2016; 13:65. [PMID: 27004516 PMCID: PMC4802843 DOI: 10.1186/s12974-016-0529-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/13/2016] [Indexed: 12/11/2022] Open
Abstract
Background Microglial cells have been implicated in neuroinflammation-mediated injury in the brain, including neurodevelopmental disorders such as cerebral palsy (CP) and autism. Pro-inflammatory activation of microglial cells results in the impairment of their neuroprotective functions, leading to an exaggerated, ongoing immune dysregulation that can persist long after the initial insult. We have previously shown that dendrimer-mediated delivery of an anti-inflammatory agent can attenuate inflammation in a rabbit model of maternal inflammation-induced CP and significantly improve the motor phenotype, due to the ability of the dendrimer to selectively localize in activated microglia. Methods To elucidate the interactions between dendrimers and microglia, we created an organotypic whole-hemisphere brain slice culture model from newborn rabbits with and without exposure to inflammation in utero. We then used this model to analyze the dynamics of microglial migration and their interactions with dendrimers in the presence of neuroinflammation. Results Microglial cells in animals with CP had an amoeboid morphology and impaired cell migration, demonstrated by decreased migration distance and velocity when compared to cells in healthy, age-matched controls. However, this decreased migration was associated with a greater, more rapid dendrimer uptake compared to microglial cells from healthy controls. Conclusions This study demonstrates that maternal intrauterine inflammation is associated with impaired microglial function and movement in the newborn brain. This microglial impairment may play a role in the development of ongoing brain injury and CP in the offspring. Increased uptake of dendrimers by the “impaired” microglia can be exploited to deliver drugs specifically to these cells and modulate their functions. Host tissue and target cell characteristics are important aspects to be considered in the design and evaluation of targeted dendrimer-based nanotherapeutics for improved and sustained efficacy. This ex vivo model also provides a rapid screening tool for evaluation of the effects of various therapies on microglial function. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0529-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Fan Zhang
- Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA.,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Elizabeth Nance
- Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA.,Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.,Present address: Department of Chemical Engineering, University of Washington, Seattle, WA, 98195, USA
| | - Yossef Alnasser
- Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Rangaramanujam Kannan
- Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA.,Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA.,Hugo Moser Research Center, Kennedy Krieger Institute, Baltimore, MD, 21205, USA
| | - Sujatha Kannan
- Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21231, USA. .,Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA. .,Hugo Moser Research Center, Kennedy Krieger Institute, Baltimore, MD, 21205, USA. .,Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
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Orihuela R, McPherson CA, Harry GJ. Microglial M1/M2 polarization and metabolic states. Br J Pharmacol 2016; 173:649-65. [PMID: 25800044 PMCID: PMC4742299 DOI: 10.1111/bph.13139] [Citation(s) in RCA: 1242] [Impact Index Per Article: 155.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 03/05/2015] [Accepted: 03/13/2015] [Indexed: 02/06/2023] Open
Abstract
Microglia are critical nervous system-specific immune cells serving as tissue-resident macrophages influencing brain development, maintenance of the neural environment, response to injury and repair. As influenced by their environment, microglia assume a diversity of phenotypes and retain the capability to shift functions to maintain tissue homeostasis. In comparison with peripheral macrophages, microglia demonstrate similar and unique features with regards to phenotype polarization, allowing for innate immunological functions. Microglia can be stimulated by LPS or IFN-γ to an M1 phenotype for expression of pro-inflammatory cytokines or by IL-4/IL-13 to an M2 phenotype for resolution of inflammation and tissue repair. Increasing evidence suggests a role of metabolic reprogramming in the regulation of the innate inflammatory response. Studies using peripheral immune cells demonstrate that polarization to an M1 phenotype is often accompanied by a shift in cells from oxidative phosphorylation to aerobic glycolysis for energy production. More recently, the link between polarization and mitochondrial energy metabolism has been considered in microglia. Under these conditions, energy demands would be associated with functional activities and cell survival and thus, may serve to influence the contribution of microglia activation to various neurodegenerative conditions. This review examines the polarization states of microglia and their relationship to mitochondrial metabolism. Additional supporting experimental data are provided to demonstrate mitochondrial metabolic shifts in primary microglia and the BV-2 microglia cell line induced under LPS (M1) and IL-4/IL-13 (M2) polarization.
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Affiliation(s)
- Ruben Orihuela
- Neurotoxicology Group, National Toxicology Program Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Christopher A McPherson
- Neurotoxicology Group, National Toxicology Program Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Gaylia Jean Harry
- Neurotoxicology Group, National Toxicology Program Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
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Cannabinoid CB2 Receptor Mediates Nicotine-Induced Anti-Inflammation in N9 Microglial Cells Exposed to β Amyloid via Protein Kinase C. Mediators Inflamm 2016; 2016:4854378. [PMID: 26884647 PMCID: PMC4738711 DOI: 10.1155/2016/4854378] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 12/07/2015] [Accepted: 12/16/2015] [Indexed: 01/08/2023] Open
Abstract
Background. Reducing β amyloid- (Aβ-) induced microglial activation is considered to be effective in treating Alzheimer's disease (AD). Nicotine attenuates Aβ-induced microglial activation; the mechanism, however, is still elusive. Microglia could be activated into classic activated state (M1 state) or alternative activated state (M2 state); the former is cytotoxic and the latter is neurotrophic. In this investigation, we hypothesized that nicotine attenuates Aβ-induced microglial activation by shifting microglial M1 to M2 state, and cannabinoid CB2 receptor and protein kinase C mediate the process. Methods. We used Aβ1–42 to activate N9 microglial cells and observed nicotine-induced effects on microglial M1 and M2 biomarkers by using western blot, immunocytochemistry, and enzyme-linked immunosorbent assay (ELISA). Results. We found that nicotine reduced the levels of M1 state markers, including inducible nitric oxide synthase (iNOS) expression and tumor necrosis factor α (TNF-α) and interleukin- (IL-) 6 releases; meanwhile, it increased the levels of M2 state markers, including arginase-1 (Arg-1) expression and brain-derived neurotrophic factor (BDNF) release, in the Aβ-stimulated microglia. Coadministration of cannabinoid CB2 receptor antagonist or protein kinase C (PKC) inhibitor partially abolished the nicotine-induced effects. Conclusion. These findings indicated that cannabinoid CB2 receptor mediates nicotine-induced anti-inflammation in microglia exposed to Aβ via PKC.
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41
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Franco R, Fernández-Suárez D. Alternatively activated microglia and macrophages in the central nervous system. Prog Neurobiol 2015; 131:65-86. [PMID: 26067058 DOI: 10.1016/j.pneurobio.2015.05.003] [Citation(s) in RCA: 495] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 05/22/2015] [Accepted: 05/30/2015] [Indexed: 12/20/2022]
Abstract
Macrophages are important players in the fight against viral, bacterial, fungal and parasitic infections. From a resting state they may undertake two activation pathways, the classical known as M1, or the alternative known as M2. M1 markers are mostly mediators of pro-inflammatory responses whereas M2 markers emerge for resolution and cleanup. Microglia exerts in the central nervous system (CNS) a function similar to that of macrophages in the periphery. Microglia activation and proliferation occurs in almost any single pathology affecting the CNS. Often microglia activation has been considered detrimental and drugs able to stop microglia activation were considered for the treatment of a variety of diseases. Cumulative evidence shows that microglia may undergo the alternative activation pathway, express M2-type markers and contribute to neuroprotection. This review focuses on details about the role of M2 microglia and in the approaches available for its identification. Approaches to drive the M2 phenotype and data on its potential in CNS diseases are also reviewed.
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Affiliation(s)
- Rafael Franco
- Molecular Neurobiology Laboratory, Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain; Centro Investigación Biomédica en Red: Enfermedades Neurodegenerativas (CIBERNED), Spain.
| | - Diana Fernández-Suárez
- Division of Molecular Neurobiology, Department of Neuroscience, Karolinska Institute, 17177 Stockholm, Sweden.
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42
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Ma L, Jia J, Liu X, Bai F, Wang Q, Xiong L. Activation of murine microglial N9 cells is attenuated through cannabinoid receptor CB2 signaling. Biochem Biophys Res Commun 2015; 458:92-7. [PMID: 25637536 DOI: 10.1016/j.bbrc.2015.01.073] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 01/17/2015] [Indexed: 11/25/2022]
Abstract
Inhibition of microglial activation is effective in treating various neurological disorders. Activation of microglial cannabinoid CB2 receptor induces anti-inflammatory effects, and the mechanism, however, is still elusive. Microglia could be activated into the classic activated state (M1 state) or the alternative activated state (M2 state), the former is cytotoxic, and the latter is neurotrophic. In this study, we used lipopolysaccharide (LPS) plus interferon-γ (IFNγ) to activate N9 microglia and hypothesized the pretreatment with cannabinoid CB2 receptor agonist AM1241 attenuates microglial activation by shifting microglial M1 to M2 state. We found that pretreatment with 5 μM AM1241 at 1 h before microglia were exposed to LPS plus IFNγ decreased the expression of inducible nitric oxide synthase (iNOS) and the release of pro-inflammatory factors, increased the expression of arginase 1 (Arg-1) and the release of anti-inflammatory and neurotrophic factors in microglia. However, these effects induced by AM1241 pretreatment were significantly reversed in the presence of 10 μM cannabinoid CB2 receptor antagonist AM630 or 10 μM protein kinase C (PKC) inhibitor chelerythrine. These findings indicated that AM1241 pretreatment attenuates microglial activation by shifting M1 to M2 activated state via CB2 receptor, and the AM1241-induced anti-inflammatory effects may be mediated by PKC.
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Affiliation(s)
- Lei Ma
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Ji Jia
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Xiangyu Liu
- Department of Plastic Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Fuhai Bai
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Qiang Wang
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
| | - Lize Xiong
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
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Cheng YL, Choi Y, Sobey CG, Arumugam TV, Jo DG. Emerging roles of the γ-secretase-notch axis in inflammation. Pharmacol Ther 2014; 147:80-90. [PMID: 25448038 DOI: 10.1016/j.pharmthera.2014.11.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 11/03/2014] [Indexed: 12/14/2022]
Abstract
γ-Secretase is a distinct proteolytic complex required for the activation of many transmembrane proteins. The cleavage of substrates by γ-secretase plays diverse biological roles in producing essential products for the organism. More than 90 transmembrane proteins have been reported to be substrates of γ-secretase. Two of the most widely known and studied of these substrates are the amyloid precursor protein (APP) and the Notch receptor, which are precursors for the generation of amyloid-β (Aβ) and the Notch intracellular domain (NICD), respectively. The wide spectrum of γ-secretase substrates has made analyses of the pathology of γ-secretase-related diseases and underlying mechanisms challenging. Inflammation is an important aspect of disease pathology that requires an in-depth analysis. γ-Secretase may contribute to disease development or progression by directly increasing and regulating production of pro-inflammatory cytokines. This review summarizes recent evidence for a role of γ-secretase in inflammatory diseases, and discusses the potential use of γ-secretase inhibitors as an effective future treatment option.
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Affiliation(s)
- Yi-Lin Cheng
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Yuri Choi
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | | | - Thiruma V Arumugam
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Dong-Gyu Jo
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea.
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44
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Chen BY, Zheng MH, Chen Y, Du YL, Sun XL, Zhang X, Duan L, Gao F, Liang L, Qin HY, Luo ZJ, Han H. Myeloid-Specific Blockade of Notch Signaling by RBP-J Knockout Attenuates Spinal Cord Injury Accompanied by Compromised Inflammation Response in Mice. Mol Neurobiol 2014; 52:1378-1390. [PMID: 25344316 DOI: 10.1007/s12035-014-8934-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 10/09/2014] [Indexed: 12/28/2022]
Abstract
The outcome of spinal cord injury (SCI) is determined by both neural cell-intrinsic survival pathways and tissue microenvironment-derived signals. Macrophages dominating the inflammatory responses in SCI possess both destructive and reparative potentials, according to their activation status. Notch signaling is involved in both cell survival and macrophage-mediated inflammation, but a comprehensive role of Notch signaling in SCI has been elusive. In this study, we compared the effects of general Notch blockade by a pharmaceutical γ-secretase inhibitor (GSI) and myeloid-specific Notch signal disruption by recombination signal binding protein Jκ (RBP-J) knockout on SCI. The administration of Notch signal inhibitor GSI resulted in worsened hind limb locomotion and exacerbated inflammation. However, mice lacking RBP-J, the critical transcription factor mediating signals from all four mammalian Notch receptors, in myeloid lineage displayed promoted functional recovery, attenuated glial scar formation, improved neuronal survival and axon regrowth, and mitigated inflammatory response after SCI. These benefits were accompanied by enhanced AKT activation in the lesion area after SCI. These findings demonstrate that abrogating Notch signal in myeloid cells ameliorates inflammation response post-SCI and promotes functional recovery, but general pharmaceutical Notch interception has opposite effects. Therefore, clinical intervention of Notch signaling in SCI needs to pinpoint myeloid lineage to avoid the counteractive effects of global inhibition.
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Affiliation(s)
- Bei-Yu Chen
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Chang-Le West Street #169, Xi'an, 710032, China.,Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Chang-Le West Street #169, Xi'an, 710032, China
| | - Min-Hua Zheng
- Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Chang-Le West Street #169, Xi'an, 710032, China.
| | - Yan Chen
- Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Chang-Le West Street #169, Xi'an, 710032, China
| | - Yan-Ling Du
- Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Chang-Le West Street #169, Xi'an, 710032, China
| | - Xiao-Long Sun
- Institute of Neurosciences, Fourth Military Medical University, Xi'an, 710032, China
| | - Xing Zhang
- Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Chang-Le West Street #169, Xi'an, 710032, China
| | - Li Duan
- Institute of Neurosciences, Fourth Military Medical University, Xi'an, 710032, China
| | - Fang Gao
- Institute of Neurosciences, Fourth Military Medical University, Xi'an, 710032, China
| | - Liang Liang
- Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Chang-Le West Street #169, Xi'an, 710032, China
| | - Hong-Yan Qin
- Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Chang-Le West Street #169, Xi'an, 710032, China
| | - Zhuo-Jing Luo
- Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Chang-Le West Street #169, Xi'an, 710032, China.
| | - Hua Han
- Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Chang-Le West Street #169, Xi'an, 710032, China.
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45
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Therapeutically targeting neuroinflammation and microglia after acute ischemic stroke. BIOMED RESEARCH INTERNATIONAL 2014; 2014:297241. [PMID: 25089266 PMCID: PMC4095830 DOI: 10.1155/2014/297241] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 06/10/2014] [Indexed: 12/11/2022]
Abstract
Inflammation has a pivotal role in the pathogenesis of ischemic stroke, and recent studies posit that inflammation acts as a double-edged sword, not only detrimentally augmenting secondary injury, but also potentially promoting recovery. An initial event of inflammation in ischemic stroke is the activation of microglia, leading to production of both pro- and anti-inflammatory mediators acting through multiple receptor signaling pathways. In this review, we discuss the role of microglial mediators in acute ischemic stroke and elaborate on preclinical and clinical studies focused on microglia in stroke models. Understanding how microglia can lead to both pro- and anti-inflammatory responses may be essential to implement therapeutic strategies using immunomodulatory interventions in ischemic stroke.
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