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Matteoli M. The role of microglial TREM2 in development: A path toward neurodegeneration? Glia 2024; 72:1544-1554. [PMID: 38837837 DOI: 10.1002/glia.24574] [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: 01/20/2024] [Revised: 05/11/2024] [Accepted: 05/21/2024] [Indexed: 06/07/2024]
Abstract
The nervous and the immune systems undergo a continuous cross talk, starting from early development and continuing throughout adulthood and aging. Defects in this cross talk contribute to neurodevelopmental and neurodegenerative diseases. Microglia are the resident immune cells in the brain that are primarily involved in this bidirectional communication. Among the microglial genes, trem2 is a key player, controlling the functional state of microglia and being at the forefront of many processes that require interaction between microglia and other brain components, such as neurons and oligodendrocytes. The present review focuses on the early developmental window, describing the early brain processes in which TREM2 is primarily involved, including the modulation of synapse formation and elimination, the control of neuronal bioenergetic states as well as the contribution to myelination processes and neuronal circuit formation. By causing imbalances during these early maturation phases, dysfunctional TREM2 may have a striking impact on the adult brain, making it a more sensitive target for insults occurring during adulthood and aging.
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Affiliation(s)
- Michela Matteoli
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
- Neuro Center, IRCCS Humanitas Research Hospital, Milan, Italy
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2
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Wątroba M, Grabowska AD, Szukiewicz D. Chemokine CX3CL1 (Fractalkine) Signaling and Diabetic Encephalopathy. Int J Mol Sci 2024; 25:7527. [PMID: 39062768 PMCID: PMC11277241 DOI: 10.3390/ijms25147527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 07/04/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
Diabetes mellitus (DM) is the most common metabolic disease in humans, and its prevalence is increasing worldwide in parallel with the obesity pandemic. A lack of insulin or insulin resistance, and consequently hyperglycemia, leads to many systemic disorders, among which diabetic encephalopathy (DE) is a long-term complication of the central nervous system (CNS), characterized by cognitive impairment and motor dysfunctions. The role of oxidative stress and neuroinflammation in the pathomechanism of DE has been proven. Fractalkine (CX3CL1) has unique properties as an adhesion molecule and chemoattractant, and by acting on its only receptor, CX3CR1, it regulates the activity of microglia in physiological states and neuroinflammation. Depending on the clinical context, CX3CL1-CX3CR1 signaling may have neuroprotective effects by inhibiting the inflammatory process in microglia or, conversely, maintaining/intensifying inflammation and neurotoxicity. This review discusses the evidence supporting that the CX3CL1-CX3CR1 pair is neuroprotective and other evidence that it is neurotoxic. Therefore, interrupting the vicious cycle within neuron-microglia interactions by promoting neuroprotective effects or inhibiting the neurotoxic effects of the CX3CL1-CX3CR1 signaling axis may be a therapeutic goal in DE by limiting the inflammatory response. However, the optimal approach to prevent DE is simply tight glycemic control, because the elimination of dysglycemic states in the CNS abolishes the fundamental mechanisms that induce this vicious cycle.
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Affiliation(s)
| | | | - Dariusz Szukiewicz
- Laboratory of the Blood-Brain Barrier, Department of Biophysics, Physiology & Pathophysiology, Medical University of Warsaw, Chałubińskiego 5, 02-400 Warsaw, Poland; (M.W.); (A.D.G.)
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3
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Fremuth LE, Hu H, van de Vlekkert D, Annunziata I, Weesner JA, Gomero E, d'Azzo A. Neuraminidase 1 regulates the cellular state of microglia by modulating the sialylation of Trem2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.20.595036. [PMID: 38826426 PMCID: PMC11142087 DOI: 10.1101/2024.05.20.595036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Neuraminidase 1 (Neu1) cleaves terminal sialic acids from sialoglycoproteins in endolysosomes and at the plasma membrane. As such, Neu1 regulates immune cells, primarily those of the monocytic lineage. Here we examined how Neu1 influences microglia by modulating the sialylation of full-length Trem2 (Trem2-FL), a multifunctional receptor that regulates microglial survival, phagocytosis, and cytokine production. When Neu1 was deficient/downregulated, Trem2-FL remained sialylated, accumulated intracellularly, and was excessively cleaved into a C-terminal fragment (Trem2-CTF) and an extracellular soluble domain (sTrem2), enhancing their signaling capacities. Sialylated Trem2-FL (Sia-Trem2-FL) did not hinder Trem2-FL-DAP12-Syk complex assembly but impaired signal transduction through Syk, ultimately abolishing Trem2-dependent phagocytosis. Concurrently, Trem2-CTF-DAP12 complexes dampened NFκB signaling, while sTrem2 propagated Akt-dependent cell survival and NFAT1-mediated production of TNFα and CCL3. Because Neu1 and Trem2 are implicated in neurodegenerative/neuroinflammatory diseases, including Alzheimer disease (AD) and sialidosis, modulating Neu1 activity represents a therapeutic approach to broadly regulate microglia-mediated neuroinflammation.
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Zhou X, Shi Q, Zhang X, Gu L, Li J, Quan S, Zhao X, Li Q. ApoE4-mediated Blood-Brain Barrier Damage in Alzheimer's Disease: Progress and Prospects. Brain Res Bull 2023; 199:110670. [PMID: 37224887 DOI: 10.1016/j.brainresbull.2023.110670] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 05/15/2023] [Accepted: 05/17/2023] [Indexed: 05/26/2023]
Abstract
Late-onset Alzheimer's disease (AD), a neurodegenerative disease, is expected in the elderly population and adversely affects families and society. The extensive debate on the deposition of amyloid (Aβ), abnormal phosphorylation of Tau protein, and neuroinflammation hypothesis in the pathogenesis of AD has been recognized by many scholars. The blood-brain barrier (BBB) is an essential physical barrier that protects the brain from external material interference, and its integrity affects the process of AD. Apolipoprotein E4 (ApoE4) has shown a critical regulatory role in many studies and is a crucial protein that affects AD. Numerous current studies on ApoE4 are based on complementary hypotheses to the three hypotheses above, ignoring the effect of ApoE4 on BBB constitutive cells and the role of the BBB in AD. In this review, we summarize the findings of the role of ApoE4 in the composition of the BBB and the value of ApoE4 for maintaining BBB integrity, which may play an essential role in changing the progression of the disease.
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Affiliation(s)
- Xuebin Zhou
- School of Pharmacy, Hangzhou Medical College, 310013, Hangzhou, Zhejiang, China
| | - Qiyuan Shi
- School of Pharmacy, Hangzhou Medical College, 310013, Hangzhou, Zhejiang, China
| | - Xinyue Zhang
- School of Pharmacy, Hangzhou Medical College, 310013, Hangzhou, Zhejiang, China
| | - Lili Gu
- School of Pharmacy, Hangzhou Medical College, 310013, Hangzhou, Zhejiang, China
| | - Jinhua Li
- School of Pharmacy, Hangzhou Medical College, 310013, Hangzhou, Zhejiang, China
| | - Shengli Quan
- School of Pharmacy, Hangzhou Medical College, 310013, Hangzhou, Zhejiang, China
| | - Xia Zhao
- School of Pharmacy, Hangzhou Medical College, 310013, Hangzhou, Zhejiang, China.
| | - Qin Li
- School of Pharmacy, Hangzhou Medical College, 310013, Hangzhou, Zhejiang, China.
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5
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Popescu AS, Butler CA, Allendorf DH, Piers TM, Mallach A, Roewe J, Reinhardt P, Cinti A, Redaelli L, Boudesco C, Pradier L, Pocock JM, Thornton P, Brown GC. Alzheimer's disease-associated R47H TREM2 increases, but wild-type TREM2 decreases, microglial phagocytosis of synaptosomes and neuronal loss. Glia 2023; 71:974-990. [PMID: 36480007 PMCID: PMC10952257 DOI: 10.1002/glia.24318] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/22/2022] [Accepted: 11/25/2022] [Indexed: 12/14/2022]
Abstract
Triggering receptor on myeloid cells 2 (TREM2) is an innate immune receptor, upregulated on the surface of microglia associated with amyloid plaques in Alzheimer's disease (AD). Individuals heterozygous for the R47H variant of TREM2 have greatly increased risk of developing AD. We examined the effects of wild-type (WT), R47H and knock-out (KO) of human TREM2 expression in three microglial cell systems. Addition of mouse BV-2 microglia expressing R47H TREM2 to primary mouse neuronal cultures caused neuronal loss, not observed with WT TREM2. Neuronal loss was prevented by using annexin V to block exposed phosphatidylserine, an eat-me signal and ligand of TREM2, suggesting loss was mediated by microglial phagocytosis of neurons exposing phosphatidylserine. Addition of human CHME-3 microglia expressing R47H TREM2 to LUHMES neuronal-like cells also caused loss compared to WT TREM2. Expression of R47H TREM2 in BV-2 and CHME-3 microglia increased their uptake of phosphatidylserine-beads and synaptosomes versus WT TREM2. Human iPSC-derived microglia with heterozygous R47H TREM2 had increased phagocytosis of synaptosomes vs common-variant TREM2. Additionally, phosphatidylserine liposomes increased activation of human iPSC-derived microglia expressing homozygous R47H TREM2 versus common-variant TREM2. Finally, overexpression of TREM2 in CHME-3 microglia caused increased expression of cystatin F, a cysteine protease inhibitor, and knock-down of cystatin F increased CHME-3 uptake of phosphatidylserine-beads. Together, these data suggest that R47H TREM2 may increase AD risk by increasing phagocytosis of synapses and neurons via greater activation by phosphatidylserine and that WT TREM2 may decrease microglial phagocytosis of synapses and neurons via cystatin F.
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Affiliation(s)
- Alma S. Popescu
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - Claire A. Butler
- Department of BiochemistryUniversity of CambridgeCambridgeUK
- Neuroscience, BioPharmaceuticals R&DAstraZenecaCambridgeUK
| | | | - Thomas M. Piers
- Department of NeuroinflammationUCL Queen Square Institute of NeurologyLondonUK
| | - Anna Mallach
- Department of NeuroinflammationUCL Queen Square Institute of NeurologyLondonUK
| | - Julian Roewe
- Neuroscience DiscoveryAbbVie Deutschland GmbH & Co. KGLudwigshafenGermany
| | - Peter Reinhardt
- Neuroscience DiscoveryAbbVie Deutschland GmbH & Co. KGLudwigshafenGermany
| | | | | | | | | | - Jennifer M. Pocock
- Department of NeuroinflammationUCL Queen Square Institute of NeurologyLondonUK
| | - Peter Thornton
- Neuroscience, BioPharmaceuticals R&DAstraZenecaCambridgeUK
| | - Guy C. Brown
- Department of BiochemistryUniversity of CambridgeCambridgeUK
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Bennett ML. A polarizing answer - microglia in Nasu-Hakola disease. Nat Immunol 2023; 24:379-381. [PMID: 36823406 DOI: 10.1038/s41590-023-01440-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Mariko L Bennett
- Department of Pediatrics, Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Chronic Pain after Bone Fracture: Current Insights into Molecular Mechanisms and Therapeutic Strategies. Brain Sci 2022; 12:brainsci12081056. [PMID: 36009119 PMCID: PMC9406150 DOI: 10.3390/brainsci12081056] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/20/2022] [Accepted: 08/06/2022] [Indexed: 12/12/2022] Open
Abstract
Bone fracture following traumatic injury or due to osteoporosis is characterized by severe pain and motor impairment and is a major cause of global mortality and disability. Fracture pain often originates from mechanical distortion of somatosensory nerve terminals innervating bones and muscles and is maintained by central sensitization. Chronic fracture pain (CFP) after orthopedic repairs is considered one of the most critical contributors to interference with the physical rehabilitation and musculoskeletal functional recovery. Analgesics available for CFP in clinics not only have poor curative potency but also have considerable side effects; therefore, it is important to further explore the pathogenesis of CFP and identify safe and effective therapies. The typical physiopathological characteristics of CFP are a neuroinflammatory response and excitatory synaptic plasticity, but the specific molecular mechanisms involved remain poorly elucidated. Recent progress has deepened our understanding of the emerging properties of chemokine production, proinflammatory mediator secretion, caspase activation, neurotransmitter release, and neuron-glia interaction in initiating and sustaining synaptogenesis, synaptic strength, and signal transduction in central pain sensitization, indicating the possibility of targeting neuroinflammation to prevent and treat CFP. This review summarizes current literature on the excitatory synaptic plasticity, microgliosis, and microglial activation-associated signaling molecules and discusses the unconventional modulation of caspases and stimulator of interferon genes (STING) in the pathophysiology of CFP. We also review the mechanisms of action of analgesics in the clinic and their side effects as well as promising therapeutic candidates (e.g., specialized pro-resolving mediators, a caspase-6 inhibitor, and a STING agonist) for pain relief by the attenuation of neuroinflammation with the aim of better managing patients undergoing CFP in the clinical setting.
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Zhao JF, Ren T, Li XY, Guo TL, Liu CH, Wang X. Research Progress on the Role of Microglia Membrane Proteins or Receptors in Neuroinflammation and Degeneration. Front Cell Neurosci 2022; 16:831977. [PMID: 35281298 PMCID: PMC8913711 DOI: 10.3389/fncel.2022.831977] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/26/2022] [Indexed: 01/01/2023] Open
Abstract
Microglia are intrinsic immune cells of the central nervous system and play a dual role (pro-inflammatory and anti-inflammatory) in the homeostasis of the nervous system. Neuroinflammation mediated by microglia serves as an important stage of ischemic hypoxic brain injury, cerebral hemorrhage disease, neurodegeneration and neurotumor of the nervous system and is present through the whole course of these diseases. Microglial membrane protein or receptor is the basis of mediating microglia to play the inflammatory role and they have been found to be upregulated by recognizing associated ligands or sensing changes in the nervous system microenvironment. They can then allosterically activate the downstream signal transduction and produce a series of complex cascade reactions that can activate microglia, promote microglia chemotactic migration and stimulate the release of proinflammatory factor such as TNF-α, IL-β to effectively damage the nervous system and cause apoptosis of neurons. In this paper, several representative membrane proteins or receptors present on the surface of microglia are systematically reviewed and information about their structures, functions and specific roles in one or more neurological diseases. And on this basis, some prospects for the treatment of novel coronavirus neurological complications are presented.
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Affiliation(s)
- Jun-Feng Zhao
- Department of Neurosurgery, Affiliated Dalian No. 3 People’s Hospital, Dalian Medical University, Dalian, China
| | - Tong Ren
- Department of Neurosurgery, Affiliated Dalian No. 3 People’s Hospital, Dalian Medical University, Dalian, China
| | - Xiang-Yu Li
- Department of Neurosurgery, Affiliated Dalian No. 3 People’s Hospital, Dalian Medical University, Dalian, China
| | - Tian-Lin Guo
- Department of Neurosurgery, Affiliated Dalian No. 3 People’s Hospital, Dalian Medical University, Dalian, China
| | - Chun-Hui Liu
- Department of Neurosurgery, Beijing Tiantan Hospital, Beijing, China
- Chun-Hui Liu,
| | - Xun Wang
- Department of Neurosurgery, Affiliated Dalian No. 3 People’s Hospital, Dalian Medical University, Dalian, China
- *Correspondence: Xun Wang,
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9
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Hu C, Li H, Li J, Luo X, Hao Y. Microglia: Synaptic modulator in autism spectrum disorder. Front Psychiatry 2022; 13:958661. [PMID: 36465285 PMCID: PMC9714329 DOI: 10.3389/fpsyt.2022.958661] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 10/28/2022] [Indexed: 11/18/2022] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by variable impairment of social communication and repetitive behaviors, highly restricted interests, and/or sensory behaviors beginning early in life. Many individuals with ASD have dysfunction of microglia, which may be closely related to neuroinflammation, making microglia play an important role in the pathogenesis of ASD. Mounting evidence indicates that microglia, the resident immune cells of the brain, are required for proper brain function, especially in the maintenance of neuronal circuitry and control of behavior. Dysfunction of microglia will ultimately affect the neural function in a variety of ways, including the formation of synapses and alteration of excitatory-inhibitory balance. In this review, we provide an overview of how microglia actively interact with neurons in physiological conditions and modulate the fate and functions of synapses. We put a spotlight on the multi-dimensional neurodevelopmental roles of microglia, especially in the essential influence of synapses, and discuss how microglia are currently thought to influence ASD progression.
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Affiliation(s)
- Cong Hu
- Division of Child Healthcare, Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Heli Li
- Division of Child Healthcare, Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jinhui Li
- Division of Child Healthcare, Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoping Luo
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Hao
- Division of Child Healthcare, Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Stepanichev MY. Using Genome Editing for Alzheimer’s Disease Therapy: from Experiment to Clinic. NEUROCHEM J+ 2021. [DOI: 10.1134/s1819712421040139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Teipel S, Bruno D, Plaska CR, Heslegrave A, Ramos-Cejudo J, Osorio RS, Zetterberg H, Blennow K, Pomara N. Association of CSF sTREM2, a marker of microglia activation, with cholinergic basal forebrain volume in major depressive disorder. J Affect Disord 2021; 293:429-434. [PMID: 34246952 PMCID: PMC8803308 DOI: 10.1016/j.jad.2021.06.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/16/2021] [Accepted: 06/17/2021] [Indexed: 01/17/2023]
Abstract
BACKGROUND Inflammatory mechanisms are believed to contribute to the manifestation of major depressive disorder (MDD). Central cholinergic activity may moderate this effect. Here, we tested if volume of the cholinergic basal forebrain is associated with cerebrospinal fluid (CSF) levels of sTREM2 as a marker of microglial activation in people with late life MDD. METHODS Basal forebrain volume was determined from structural MRI scans and levels of CSF sTREM2 with immunoassay in 29 people with late-life MDD and 20 healthy older controls at baseline and 3 years follow-up. Associations were determined using Bayesian analysis of covariance. RESULTS We found moderate level of evidence for an association of lower CSF levels of sTREM2 at 3 years follow up with MDD (Bayes factor in favor of an effect = 7.9). This level of evidence prevailed when controlling for overall antidepressant treatment and CSF levels of markers of AD pathology, i.e., Aβ42/Aβ40, ptau181 and total tau. Evidence was in favor of absence of an effect for baseline levels of CSF sTREM2 in MDD cases and for baseline and follow up data in controls. LIMITATIONS The sample size of repeated CSF examinations was relatively small. Therefore, we used Bayesian sequential analysis to assess if effects were affected by sample size. Still, the number of cases was too small to stratify effects for different antidepressive treatments. CONCLUSIONS Our data agree with the assumption that central cholinergic system integrity may contribute to regulation of microglia activity in late-life MDD.
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Affiliation(s)
- Stefan Teipel
- Department of Psychosomatic Medicine, University Medicine Rostock, Rostock, Germany; DZNE, German Center for Neurodegenerative Diseases, Rostock, Germany.
| | - Davide Bruno
- School of Psychology, Liverpool John Moores University, Liverpool, United Kingdom
| | | | - Amanda Heslegrave
- UK Dementia Research Institute at UCL, London, UK,Department of Neurodegeneradve Disease, UCL Institute of Neurology, Queen Square, London, UK
| | - Jaime Ramos-Cejudo
- Department of Psychiatry, New York University (NYU) Grossman School of Medicine, New York, NY, USA
| | - Ricardo S. Osorio
- Nathan Kline Institute, Orangeburg, NY, USA,Department of Psychiatry, New York University (NYU) Grossman School of Medicine, New York, NY, USA
| | - Henrik Zetterberg
- UK Dementia Research Institute at UCL, London, UK,Department of Neurodegeneradve Disease, UCL Institute of Neurology, Queen Square, London, UK,Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Kaj Blennow
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, the Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Nunzio Pomara
- Nathan Kline Institute, Orangeburg, NY, USA,Department of Psychiatry, New York University (NYU) Grossman School of Medicine, New York, NY, USA
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Discovery of Active Ingredients Targeted TREM2 by SPR Biosensor-UPLC/MS Recognition System, and Investigating the Mechanism of Anti-Neuroinflammatory Activity on the Lignin-Amides from Datura metel Seeds. Molecules 2021; 26:molecules26195946. [PMID: 34641490 PMCID: PMC8512677 DOI: 10.3390/molecules26195946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/26/2021] [Accepted: 09/27/2021] [Indexed: 12/20/2022] Open
Abstract
As a new target protein for Alzheimer’s disease (AD), the triggering receptor expressed on myeloid Cells 2 (TREM2) was expressed on the surface of microglia, which was shown to regulate neuroinflammation, be associated with a variety of neuropathologic, and regarded as a potential indicator for monitoring AD. In this study, a novel recognition system based on surface plasmon resonance (SPR) for the TREM2 target spot was established coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-MS), in order to screen the active ingredients targeting TREM2 from Datura metel seeds. The results showed that four lignan-amides were discovered as candidate compounds by SPR biosensor-UPLC/MS recognition analysis. According to the guidance of the active ingredients discovered by the system, the lignin-amides from Datura metel seeds (LDS) were preliminarily identified as containing 27 lignan-amides, which were enriched compositions by the HP-20 of Datura metel seeds. Meanwhile, the anti-inflammatory activity of LDS was evaluated in BV2 microglia induced by LPS. Our experimental results demonstrated that LDS could reduce NO release in LPS-treated BV2 microglia cells and significantly reduce the expression of the proteins of inducible Nitric Oxide Synthase (iNOS), cyclooxygenase 2 (COX-2), microtubule-associated protein tau (Tau), and ionized calcium-binding adapter molecule 1 (IBA-1). Accordingly, LDS might increase the expression of TREM2/DNAX-activating protein of 12 kDa (DAP12) and suppress the Toll-like receptor SX4 (TLR4) pathway and Recombinant NLR Family, Pyrin Domain Containing Protein 3 (NLRP3)/cysteinyl aspartate specific proteinase-1 (Caspase-1) inflammasome expression by LDS in LPS-induced BV2 microglial cells. Then, the inhibitory release of inflammatory factors Interleukin 1 beta (IL-1β), Interleukin 6 (IL-6), and Tumor necrosis factor-alpha (TNFα) inflammatory cytokines were detected to inhibit neuroinflammatory responses. The present results propose that LDS has potential as an anti-neuroinflammatory agent against microglia-mediated neuroinflammatory disorders.
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Samanci B, Bilgiç B, Gelişin Ö, Tepgeç F, Guven G, Tüfekçioğlu Z, Alaylıoğlu M, Hanagasi HA, Gürvit H, Guerreiro R, Hardy J, Emre M. TREM2 variants as a possible cause of frontotemporal dementia with distinct neuroimaging features. Eur J Neurol 2021; 28:2603-2613. [PMID: 33969597 DOI: 10.1111/ene.14908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND PURPOSE Nasu-Hakola disease (NHD) is a rare, autosomal recessive disorder characterized by skeletal and neurological symptoms. Behavioral symptoms with cognitive impairment may mimic the behavioral variant of frontotemporal dementia (bvFTD) and other early-onset dementias. Our patients were analyzed and the literature was reviewed to delineate neurological and neuroimaging findings suggestive of NHD. METHOD Fourteen patients carrying a pathogenic mutation in the TREM2 gene were found in our database. Demographic, clinical, laboratory and radiological data were retrieved and analyzed. RESULTS The presenting clinical picture was behavioral changes with cognitive decline resembling bvFTD in all patients. The mean age was 37.1 ± 4.97 years and the mean duration of the disease was 8.9 ± 3.51 years. Only two patients had typical bone cysts. Seven patients had bilateral calcification of the basal ganglia in computed tomography of the brain. Magnetic resonance imaging of the brain revealed severe atrophy of the corpus callosum, enlargement of the ventricles, atrophy of the caudate nuclei and periventricular white matter changes in all patients. Symmetrical global atrophy of the brain mainly affecting frontoparietal and lateral temporal regions were observed in all cases, and 13 patients had atrophy of the hippocampus. Cerebrospinal fluid examination of 10 patients showed elevated protein levels in six and the presence of oligoclonal bands in four patients. CONCLUSION A combination of white matter changes, enlarged ventricles, atrophy of the caudate nuclei and thinning of the corpus callosum in magnetic resonance imaging strongly suggests NHD in patients with FTD syndrome. Molecular genetic analysis should be performed in suspected cases, and families should receive genetic counseling.
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Affiliation(s)
- Bedia Samanci
- Behavioral Neurology and Movement Disorders Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Başar Bilgiç
- Behavioral Neurology and Movement Disorders Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Özlem Gelişin
- Behavioral Neurology and Movement Disorders Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Fatih Tepgeç
- Department of Medical Genetics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Gamze Guven
- Department of Genetics, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Istanbul, Turkey
| | - Zeynep Tüfekçioğlu
- Behavioral Neurology and Movement Disorders Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Merve Alaylıoğlu
- Department of Medical Biology, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Hasmet A Hanagasi
- Behavioral Neurology and Movement Disorders Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Hakan Gürvit
- Behavioral Neurology and Movement Disorders Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Rita Guerreiro
- Center for Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI, USA
| | - John Hardy
- Department of Neurodegenerative Disorders, Institute of Neurology, University College London, London, UK
| | - Murat Emre
- Behavioral Neurology and Movement Disorders Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
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Triviño JJ, von Bernhardi R. The effect of aged microglia on synaptic impairment and its relevance in neurodegenerative diseases. Neurochem Int 2021; 144:104982. [PMID: 33556444 DOI: 10.1016/j.neuint.2021.104982] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 01/31/2021] [Accepted: 02/01/2021] [Indexed: 02/07/2023]
Abstract
Microglia serve key functions in the central nervous system (CNS), participating in the establishment and regulation of synapses and the neuronal network, and regulating activity-dependent plastic changes. As the neuroimmune system, they respond to endogenous and exogenous signals to protect the CNS. In aging, one of the main changes is the establishment of inflamm-aging, a mild chronic inflammation that reduces microglial response to stressors. Neuroinflammation depends mainly on the increased activation of microglia. Microglia over-activation may result in a reduced capacity for performing normal functions related to migration, clearance, and the adoption of an anti-inflammatory state, contributing to an increased susceptibility for neurodegeneration. Oxidative stress contributes both to aging and to the progression of neurodegenerative diseases. Increased production of reactive oxygen species (ROS) and neuroinflammation associated with age- and disease-dependent mechanisms affect synaptic activity and neurotransmission, leading to cognitive dysfunction. Astrocytes prevent microglial cell cytotoxicity by mechanisms mediated by transforming growth factor β1 (TGFβ1). However, TGFβ1-Smad3 pathway is impaired in aging, and the age-related impairment of TGFβ signaling can reduce protective activation while facilitating cytotoxic activation of microglia. A critical analysis on the effect of aging microglia on neuronal function is relevant for the understanding of age-related changes on neuronal function. Here, we present evidence in the context of the "microglial dysregulation hypothesis", which leads to the reduction of the protective functions and increased cytotoxicity of microglia, to discuss the mechanisms involved in neurodegenerative changes and Alzheimer's disease.
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Affiliation(s)
- Juan José Triviño
- Department of Neurology, Pontificia Universidad Católica de Chile School of Medicine, Laboratory of Neuroscience. Marcoleta 391, Santiago, Chile
| | - Rommy von Bernhardi
- Department of Neurology, Pontificia Universidad Católica de Chile School of Medicine, Laboratory of Neuroscience. Marcoleta 391, Santiago, Chile; Faculty of Health Sciences, Universidad San Sebastián, Lota 2465, Santiago, Chile.
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Verkhratsky A, Sun D, Tanaka J. Snapshot of microglial physiological functions. Neurochem Int 2021; 144:104960. [PMID: 33460721 DOI: 10.1016/j.neuint.2021.104960] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 02/08/2023]
Abstract
Microglia as a defensive arm of the nervous system emerged early in evolution. The surveilling microglia with motile and ramified processes are the main phenotype in the healthy CNS; the surveilling microglial patrol neuronal somata, dendrites, dendritic spines and axons. Increasing evidence suggests that microglia play fundamental roles in development, maturation and ageing of the brain, as well as contribute to a variety of physiological brain processes including sleep and circadian rhythm. Physiological state of microglia is tightly regulated by brain microenvironment and controlled by a sophisticated system of receptors and signalling cascades including ionotropic and metabotropic purinoceptors, pattern-recognition receptors, and receptors for chemokines and cytokines. Microglia also utilise ion channels and transporters in regulating ionic homeostasis and various aspects of microglial function. The major ion transporters expressed by microglia include Na+/H+ exchanger 1 and Na+/Ca2+ exchangers, which are involved in regulation of pHi and Ca2+ homeostasis during microglial physiological responses. Microglial cells control development, maturation and plasticity of neuronal ensembles through controlled physiological phagocytosis of synapses or synaptic fragments - processes known as synaptic pruning and trogocytosis. This special issue on "Physiological roles of microglia" is an assembly of papers written by the leading experts in this research field. We start this special issue with this snapshot of microglial physiological functions as a prelude to the indepth discussion of microglia in physiological processes in the nervous system.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Dandan Sun
- Department of Neurology and Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, PA, 15213, USA; Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA, 15213, USA.
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Ehime, 791-0295, Japan.
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