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Abarca-Merlin DM, Martínez-Durán JA, Medina-Pérez JD, Rodríguez-Santos G, Alvarez-Arellano L. From Immunity to Neurogenesis: Toll-like Receptors as Versatile Regulators in the Nervous System. Int J Mol Sci 2024; 25:5711. [PMID: 38891900 PMCID: PMC11171594 DOI: 10.3390/ijms25115711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/10/2024] [Accepted: 05/11/2024] [Indexed: 06/21/2024] Open
Abstract
Toll-like receptors (TLRs) are among the main components of the innate immune system. They can detect conserved structures in microorganisms and molecules associated with stress and cellular damage. TLRs are expressed in resident immune cells and both neurons and glial cells of the nervous system. Increasing evidence is emerging on the participation of TLRs not only in the immune response but also in processes of the nervous system, such as neurogenesis and cognition. Below, we present a review of the literature that evaluates the expression and role of TLRs in processes such as neurodevelopment, behavior, cognition, infection, neuroinflammation, and neurodegeneration.
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Affiliation(s)
- Daniela Melissa Abarca-Merlin
- Laboratorio de Investigación en Neurociencias, Hospital Infantil de México Federico Gómez, Av. Dr. Márquez 162. Colonia Doctores, Mexico City 06720, Mexico; (D.M.A.-M.)
| | - J. Abigail Martínez-Durán
- Laboratorio de Investigación en Neurociencias, Hospital Infantil de México Federico Gómez, Av. Dr. Márquez 162. Colonia Doctores, Mexico City 06720, Mexico; (D.M.A.-M.)
| | - J. David Medina-Pérez
- Laboratorio de Investigación en Neurociencias, Hospital Infantil de México Federico Gómez, Av. Dr. Márquez 162. Colonia Doctores, Mexico City 06720, Mexico; (D.M.A.-M.)
| | - Guadalupe Rodríguez-Santos
- Laboratorio de Investigación en Neurociencias, Hospital Infantil de México Federico Gómez, Av. Dr. Márquez 162. Colonia Doctores, Mexico City 06720, Mexico; (D.M.A.-M.)
| | - Lourdes Alvarez-Arellano
- Laboratorio de Investigación en Neurociencias, Hospital Infantil de México Federico Gómez, Av. Dr. Márquez 162. Colonia Doctores, Mexico City 06720, Mexico; (D.M.A.-M.)
- CONAHCYT-Hospital Infantil de México Federico Gómez, Mexico City 06720, Mexico
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Sawada K, Kamiya S, Kobayashi T. Neonatal Exposure to Lipopolysaccharide Promotes Neurogenesis of Subventricular Zone Progenitors in the Developing Neocortex of Ferrets. Int J Mol Sci 2023; 24:14962. [PMID: 37834410 PMCID: PMC10573966 DOI: 10.3390/ijms241914962] [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: 09/06/2023] [Revised: 09/29/2023] [Accepted: 10/03/2023] [Indexed: 10/15/2023] Open
Abstract
Lipopolysaccharide (LPS) is a natural agonist of toll-like receptor 4 that serves a role in innate immunity. The current study evaluated the LPS-mediated regulation of neurogenesis in the subventricular zone (SVZ) progenitors, that is, the basal radial glia and intermediate progenitors (IPs), in ferrets. Ferret pups were subcutaneously injected with LPS (500 μg/g of body weight) on postnatal days (PDs) 6 and 7. Furthermore, 5-ethynyl-2'-deoxyuridine (EdU) and 5-bromo-2'-deoxyuridine (BrdU) were administered on PDs 5 and 7, respectively, to label the post-proliferative and proliferating cells in the inner SVZ (iSVZ) and outer SVZ (oSVZ). A significantly higher density of BrdU single-labeled proliferating cells was observed in the iSVZ of LPS-exposed ferrets than in controls but not in post-proliferative EdU single-labeled and EdU/BrdU double-labeled self-renewing cells. BrdU single-labeled cells exhibited a lower proportion of Tbr2 immunostaining in LPS-exposed ferrets (22.2%) than in controls (42.6%) and a higher proportion of Ctip2 immunostaining in LPS-exposed ferrets (22.2%) than in controls (8.6%). The present findings revealed that LPS modified the neurogenesis of SVZ progenitors. Neonatal LPS exposure facilitates the proliferation of SVZ progenitors, followed by the differentiation of Tbr2-expressing IPs into Ctip2-expressing immature neurons.
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Affiliation(s)
- Kazuhiko Sawada
- Department of Nutrition, Faculty of Medical and Health Sciences, Tsukuba International University, Tsuchiura 300-0051, Japan
| | - Shiori Kamiya
- Department of Regulation Biology, Faculty of Science, Saitama University, Saitama 338-8570, Japan; (S.K.); (T.K.)
| | - Tetsuya Kobayashi
- Department of Regulation Biology, Faculty of Science, Saitama University, Saitama 338-8570, Japan; (S.K.); (T.K.)
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Vallelunga A, Iannitti T, Somma G, Russillo MC, Picillo M, De Micco R, Vacca L, Cilia R, Cicero CE, Zangaglia R, Lazzeri G, Galantucci S, Radicati FG, De Rosa A, Amboni M, Scaglione C, Tessitore A, Stocchi F, Eleopra R, Nicoletti A, Pacchetti C, Di Fonzo A, Volontè MA, Barone P, Pellecchia MT. Gender differences in microRNA expression in levodopa-naive PD patients. J Neurol 2023:10.1007/s00415-023-11707-0. [PMID: 37052669 DOI: 10.1007/s00415-023-11707-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/01/2023] [Accepted: 04/03/2023] [Indexed: 04/14/2023]
Abstract
Gender is an important factor influencing epidemiological and clinical features of Parkinson's disease (PD). We aimed to evaluate gender differences in the expression of a panel of miRNAs (miR-34a-5p, miR-146a, miR-155, miR-29a, miR-106a) possibly involved in the pathophysiology or progression of disease. Serum samples were obtained from 104 PD patients (58 men and 46 women) never treated with levodopa. We measured levels of miRNAs using quantitative PCR. Correlations between miRNA expression and clinical data were assessed using the Spearman's correlation test. We used STRING to evaluate co-expression relationship among target genes. MiR-34a-5p was significantly upregulated in PD male patients compared to PD female patients (fc: 1.62; p < 0.0001). No correlation was found with age, BMI, and disease severity, assessed by UPDRS III scale, in male and female patients. MiR-146a-5p was significantly upregulated in female as compared to male patients (fc: 3.44; p < 0.0001) and a significant correlation was also observed between disease duration and mir-146a-5p. No differences were found in the expression of miR-29a, miR-106a-5p and miR-155 between genders. Predicted target genes for miR-34a-5p and miR-146-5p and protein interactions in biological processes were reported. Our study supports the hypothesis that there are gender-specific differences in serum miRNAs expression in PD patients. Follow-up of this cohort is needed to understand if these differences may affect disease progression and response to treatment.
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Affiliation(s)
- A Vallelunga
- Department of Life Sciences and Biotechnologies, Section of Medicines and Health Products, University of Ferrara, Ferrara, Italy
| | - T Iannitti
- Department of Medical Sciences, Section of Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - G Somma
- Department of Medicine Surgery and Dentistry "Scuola Medica Salernitana", Neuroscience Section, University of Salerno, Fisciano, Italy
| | - M C Russillo
- Department of Medicine Surgery and Dentistry "Scuola Medica Salernitana", Neuroscience Section, University of Salerno, Fisciano, Italy
| | - M Picillo
- Department of Medicine Surgery and Dentistry "Scuola Medica Salernitana", Neuroscience Section, University of Salerno, Fisciano, Italy
| | - R De Micco
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - L Vacca
- IRCCS San Raffaele, Rome, Italy
| | - R Cilia
- Department of Clinical Neurosciences, Parkinson and Movement Disorders Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - C E Cicero
- Neurologic Unit, AOU "Policlinico-San Marco", Department of Medical, Surgical Sciences and Advanced Technologies, GF Ingrassia, University of Catania, Catania, Italy
| | - R Zangaglia
- Parkinson's Disease and Movement Disorders Unit, IRCCS Mondino Foundation, Pavia, Italy
| | - G Lazzeri
- IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
| | - S Galantucci
- IRCCS San Raffaele Scientific Institute, Neurology Unit, Milan, Italy
| | | | - A De Rosa
- IRCCS San Raffaele, Rome, Italy
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, Federico II University, Naples, Italy
| | - M Amboni
- Department of Medicine Surgery and Dentistry "Scuola Medica Salernitana", Neuroscience Section, University of Salerno, Fisciano, Italy
| | - C Scaglione
- IRCCS Istituto Delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - A Tessitore
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - F Stocchi
- IRCCS San Raffaele, Rome, Italy
- University San Raffaele, Roma, Italy
| | - R Eleopra
- Department of Clinical Neurosciences, Parkinson and Movement Disorders Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - A Nicoletti
- Neurologic Unit, AOU "Policlinico-San Marco", Department of Medical, Surgical Sciences and Advanced Technologies, GF Ingrassia, University of Catania, Catania, Italy
| | - C Pacchetti
- Parkinson's Disease and Movement Disorders Unit, IRCCS Mondino Foundation, Pavia, Italy
| | - A Di Fonzo
- IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
| | - M A Volontè
- IRCCS San Raffaele Scientific Institute, Neurology Unit, Milan, Italy
| | - P Barone
- Department of Medicine Surgery and Dentistry "Scuola Medica Salernitana", Neuroscience Section, University of Salerno, Fisciano, Italy
| | - M T Pellecchia
- Department of Medicine Surgery and Dentistry "Scuola Medica Salernitana", Neuroscience Section, University of Salerno, Fisciano, Italy.
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Infection, Learning, and Memory: Focus on Immune Activation and Aversive Conditioning. Neurosci Biobehav Rev 2022; 142:104898. [PMID: 36183862 DOI: 10.1016/j.neubiorev.2022.104898] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 09/19/2022] [Accepted: 09/27/2022] [Indexed: 11/22/2022]
Abstract
Here we review the effects of immune activation primarily via lipopolysaccharide (LPS), a cell wall component of Gram-negative bacteria, on hippocampal and non-hippocampal-dependent learning and memory. Rodent studies have found that LPS alters both the acquisition and consolidation of aversive learning and memory, such as those evoking evolutionarily adaptive responses like fear and disgust. The inhibitory effects of LPS on the acquisition and consolidation of contextual fear memory are discussed. LPS-induced alterations in the acquisition of taste and place-related conditioned disgust memory within bottle preference tasks and taste reactivity tests (taste-related), in addition to conditioned context avoidance tasks and the anticipatory nausea paradigm (place-related), are highlighted. Further, conditioned disgust memory consolidation may also be influenced by LPS-induced effects. Growing evidence suggests a central role of immune activation, especially pro-inflammatory cytokine activity, in eliciting the effects described here. Understanding how infection-induced immune activation alters learning and memory is increasingly important as bacterial and viral infections are found to present a risk of learning and memory impairment.
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Squillace S, Salvemini D. Toll-like receptor-mediated neuroinflammation: relevance for cognitive dysfunctions. Trends Pharmacol Sci 2022; 43:726-739. [PMID: 35753845 PMCID: PMC9378500 DOI: 10.1016/j.tips.2022.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/13/2022] [Accepted: 05/27/2022] [Indexed: 10/17/2022]
Abstract
Toll-like receptors (TLRs) are pattern recognition receptors (PRRs) with a well-documented role in the innate and adaptive immune responses. Interestingly, TLR activation has also been linked to several brain functions including neurogenesis and synaptogenesis. Increasing evidence supports TLR involvement in peripheral and central inflammation underlying normal aging and the pathogenesis of clinical conditions characterized by cognitive decline. These include not only major neurodegenerative diseases but also traumatic brain injuries, surgeries, and alcohol consumption- and chemotherapy-induced cognitive impairment. We first summarize the physiological roles of TLRs in the nervous system, and then illustrate the emerging involvement of TLRs in cognitive functions, pointing to these receptors as novel enticing pharmacological targets to develop more efficient drugs for the treatment of cognitive impairment.
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Affiliation(s)
- Silvia Squillace
- Department of Pharmacology and Physiology, and the Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, 1402 South Grand Boulevard, St. Louis, MO 63104, USA
| | - Daniela Salvemini
- Department of Pharmacology and Physiology, and the Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, 1402 South Grand Boulevard, St. Louis, MO 63104, USA.
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Cortes CJ, De Miguel Z. Precision Exercise Medicine: Sex Specific Differences in Immune and CNS Responses to Physical Activity. Brain Plast 2022; 8:65-77. [DOI: 10.3233/bpl-220139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2022] [Indexed: 11/15/2022] Open
Abstract
Physical activity is a powerful lifestyle factor capable of improving cognitive function, modifying the risk for dementia associated with neurodegeneration and possibly slowing neurodegenerative disease progression in both men and women. However, men and women show differences in the biological responses to physical activity and in the vulnerabilities to the onset, progression and outcome of neurodegenerative diseases, prompting the question of whether sex-specific regulatory mechanisms might differentially modulate the benefits of exercise on the brain. Mechanistic studies aimed to better understand how physical activity improves brain health and function suggest that the brain responds to physical exercise by overall reducing neuroinflammation and increasing neuroplasticity. Here, we review the emerging literature considering sex-specific differences in the immune system response to exercise as a potential mechanism by which physical activity affects the brain. Although the literature addressing sex differences in this light is limited, the initial findings suggest a potential influence of biological sex in the brain benefits of exercise, and lay out a scientific foundation to support very much needed studies investigating the potential effects of sex-differences on exercise neurobiology. Considering biological sex and sex-differences in the neurobiological hallmarks of exercise will help to enhance our understanding of the mechanisms by which physical activity benefits the brain and also improve the development of treatments and interventions for diseases of the central nervous system.
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Affiliation(s)
- Constanza J. Cortes
- Department of Cell, Developmental, and Integrative Biology, School of Medicine
- UAB Nathan Shock Center for the Excellence in the Study of Aging
- UAB Center for Exercise Medicine
- UAB Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, USA
| | - Zurine De Miguel
- Department of Psychology, California State University, Monterey Bay, CA, USA
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Acioglu C, Heary RF, Elkabes S. Roles of neuronal toll-like receptors in neuropathic pain and central nervous system injuries and diseases. Brain Behav Immun 2022; 102:163-178. [PMID: 35176442 DOI: 10.1016/j.bbi.2022.02.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/12/2022] [Accepted: 02/11/2022] [Indexed: 12/12/2022] Open
Abstract
Toll-like receptors (TLRs) are innate immune receptors that are expressed in immune cells as well as glia and neurons of the central and peripheral nervous systems. They are best known for their role in the host defense in response to pathogens and for the induction of inflammation in infectious and non-infectious diseases. In the central nervous system (CNS), TLRs modulate glial and neuronal functions as well as innate immunity and neuroinflammation under physiological or pathophysiological conditions. The majority of the studies on TLRs in CNS pathologies investigated their overall contribution without focusing on a particular cell type, or they analyzed TLRs in glia and infiltrating immune cells in the context of neuroinflammation and cellular activation. The role of neuronal TLRs in CNS diseases and injuries has received little attention and remains underappreciated. The primary goal of this review is to summarize findings demonstrating the pivotal and unique roles of neuronal TLRs in neuropathic pain, Alzheimer's disease, Parkinson's disease and CNS injuries. We discuss how the current findings warrant future investigations to better define the specific contributions of neuronal TLRs to these pathologies. We underline the paucity of information regarding the role of neuronal TLRs in other neurodegenerative, demyelinating, and psychiatric diseases. We draw attention to the importance of broadening research on neuronal TLRs in view of emerging evidence demonstrating their distinctive functional properties.
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Affiliation(s)
- Cigdem Acioglu
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States
| | - Robert F Heary
- Department of Neurological Surgery, Hackensack Meridian School of Medicine, Mountainside Medical Center, Montclair, NJ 07042, United States
| | - Stella Elkabes
- The Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, United States.
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Connolly MG, Bruce SR, Kohman RA. Exercise duration differentially effects age-related neuroinflammation and hippocampal neurogenesis. Neuroscience 2022; 490:275-286. [PMID: 35331843 PMCID: PMC9038708 DOI: 10.1016/j.neuroscience.2022.03.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 03/10/2022] [Accepted: 03/16/2022] [Indexed: 12/14/2022]
Abstract
The physiological effects of exercise vary as a function of frequency and length. However, research on the duration-dependent effects of exercise has focused primarily on young adults and less is known about the influence of exercise duration in the aged. The current study compared the effects of short-term and long-term running wheel access on hippocampal neurogenesis and neuroimmune markers in aged (19-23 months) male C57BL/6J mice. Aged mice were given 24-hour access to a running wheel for 14 days (short-term) or 51 days (long-term). Groups of non-running aged and young (5 months) mice served as comparison groups to detect age-related differences and effects of exercise. Long-term, but not short-term, exercise increased hippocampal neurogenesis as assessed by number of doublecortin (DCX) positive cells in the granular cell layer. Assessment of cytokines, receptors, and glial-activation markers showed the expected age-related increase compared to young controls. In the aged, exercise as a function of duration regulated select aspects of the neuroimmune profile. For instance, hippocampal expression of interleukin (IL)-10 was increased only following long-term exercise. While in contrast brain levels of IL-6 were reduced by both short- and long-term exercise. Additional findings showed that exercise does not modulate all aspects of age-related neuroinflammation and/or may have differential effects in hippocampal compared to brain samples. Overall, the data indicate that increasing exercise duration produces more robust effects on immune modulation and hippocampal neurogenesis.
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Affiliation(s)
- Meghan G Connolly
- University of Illinois Urbana-Champaign, Department of Animal Sciences, Champaign, IL, USA.
| | - Spencer R Bruce
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
| | - Rachel A Kohman
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA.
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Connolly MG, Potter OV, Sexton AR, Kohman RA. Effects of Toll-like receptor 4 inhibition on spatial memory and cell proliferation in male and female adult and aged mice. Brain Behav Immun 2021; 97:383-393. [PMID: 34343615 PMCID: PMC8453097 DOI: 10.1016/j.bbi.2021.06.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 05/19/2021] [Accepted: 06/12/2021] [Indexed: 01/04/2023] Open
Abstract
Toll-like receptors (TLRs) participate in the response to infection, stress, and injury by initiating an innate immune response. In addition, these receptors are expressed in many neural cell types and under physiological conditions are implicated in modulating cognitive function and neural plasticity in the adult and aged brain. Knockout of the Toll-like receptor 4 (TLR4) subtype enhances spatial memory and adult hippocampal neurogenesis through increasing proliferation and neuronal differentiation. Currently unknown is whether pharmacological inhibition of TLR4 produces similar enhancements in cognitive function and cell proliferation. The present study evaluated water maze performance, cytokine expression, and cell proliferation in the hippocampus of young and aged male and female C57BL6/J mice following treatment with the TLR4 antagonist, TAK-242. Further, alterations in the response to an acute stressor were evaluated in TAK-242-treated mice. Results showed that TAK-242 selectively enhanced spatial learning and memory in young females. Additionally, TAK-242 treatment reduced thigmotaxis in the water maze and lowered corticosterone levels following acute stress in females. TAK-242 decreased hippocampal interleukin (IL)-1β expression but had no effect on IL-6 or tumor necrosis factor-α (TNFα). Aged mice showed decreased cell proliferation compared to young mice, but TAK-242 administration had minimal effects on estimated Ki67 positive cell numbers. Findings indicate that pharmacological inhibition of TLR4 improves cognitive function in young females likely through attenuating stress reactivity.
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Affiliation(s)
- Meghan G. Connolly
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA
| | - Opal V. Potter
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA
| | - Ashley R. Sexton
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA
| | - Rachel A. Kohman
- University of North Carolina Wilmington, Department of Psychology, Wilmington, NC, USA
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Manivannan S, Marei O, Elalfy O, Zaben M. Neurogenesis after traumatic brain injury - The complex role of HMGB1 and neuroinflammation. Neuropharmacology 2020; 183:108400. [PMID: 33189765 DOI: 10.1016/j.neuropharm.2020.108400] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Traumatic brain injury (TBI) is amongst the leading causes of morbidity and mortality worldwide. Despite evidence of neurogenesis post-TBI, survival and integration of newborn neurons remains impaired. High Mobility Group Box protein 1 (HMGB1) is an 'alarmin' released hyper-acutely following TBI and implicated in hosting the neuro-inflammatory response to injury. It is also instrumental in mediating neurogenesis under physiological conditions. Given its dual role in mediating neuro-inflammation and neurogenesis, it serves as a promising putative target for therapeutic modulation. In this review, we discuss neurogenesis post-TBI, neuro-pharmacological aspects of HMGB1, and its potential as a therapeutic target. METHODS PubMed database was searched with varying combinations of the following search terms: HMGB1, isoforms, neurogenesis, traumatic brain injury, Toll-like receptor (TLR), receptor for advanced glycation end-products (RAGE). RESULTS Several in vitro and in vivo studies demonstrate evidence of neurogenesis post-injury. The HMGB1-RAGE axis mediates neurogenesis throughout development, whilst interaction with TLR-4 promotes the innate immune response. Studies in the context of injury demonstrate that these receptor effects are not mutually exclusive. Despite recognition of different HMGB1 isoforms based on redox/acetylation status, effects on neurogenesis post-injury remain unexplored. Recent animal in vivo studies examining HMGB1 antagonism post-TBI demonstrate predominantly positive results, but specific effects on neurogenesis and longer-term outcomes remain unclear. CONCLUSION HMGB1 is a promising therapeutic target but its effects on neurogenesis post-TBI remains unclear. Given the failure of several pharmacological strategies to improve outcomes following TBI, accurate delineation of HMGB1 signalling pathways and effects on post-injury neurogenesis are vital.
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Affiliation(s)
- S Manivannan
- Department of Neurosurgery, Southampton General Hospital, Southampton, UK
| | - O Marei
- Neuroscience and Mental Health Research Institute (NMHRI), School of Medicine, Cardiff University, UK
| | - O Elalfy
- Neuroscience and Mental Health Research Institute (NMHRI), School of Medicine, Cardiff University, UK
| | - M Zaben
- Neuroscience and Mental Health Research Institute (NMHRI), School of Medicine, Cardiff University, UK; Department of Neurosurgery, University Hospital of Wales, Cardiff, UK.
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Chen KH, Lin KC, Ko SF, Chiang JY, Guo J, Yip HK. Melatonin against acute ischaemic stroke dependently via suppressing both inflammatory and oxidative stress downstream signallings. J Cell Mol Med 2020; 24:10402-10419. [PMID: 32729676 PMCID: PMC7521217 DOI: 10.1111/jcmm.15654] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 06/06/2020] [Accepted: 06/30/2020] [Indexed: 12/16/2022] Open
Abstract
This study tested the hypothesis that melatonin (Mel) therapy preserved the brain architectural and functional integrity against ischaemic stroke (IS) dependently through suppressing the inflammatory/oxidative stress downstream signalling pathways. Adult male B6 (n = 6 per each B6 group) and TLR4 knockout (ie TLR4−/−) (n = 6 per each TLR4−/− group) mice were categorized into sham control (SCB6), SCTLR4−/−, ISB6, ISTLR4−/−, ISB6 + Mel (i.p. daily administration) and ISTLR4−/− + Mel (i.p. daily administration). By day 28 after IS, the protein expressions of inflammatory (HMBG1/TLR2/TLR4/MAL/MyD88/RAM TRIF/TRAF6/IKK‐α/p‐NF‐κB/nuclear‐NF‐κB/nuclear‐IRF‐3&7/IL‐1β/IL‐6/TNF‐α/IFN‐γ) and oxidative stress (NOX‐1/NOX‐2/ASK1/p‐MKK4&7/p‐JNK/p‐c‐JUN) downstream pathways as well as mitochondrial‐damaged markers (cytosolic cytochrome C/cyclophilin D/SRP1/autophagy) were highest in group ISB6, lowest in groups SCB6 and SCTLR4−/−, lower in group ISTLR4−/− + Mel than in groups ISTLR4−/− and ISB6 + Mel and lower in group ISB6 + Mel than in group ISTLR4−/− (all P < .0001). The brain infarct volume, brain infarct area and the number of inflammatory cells in brain (CD14/F4‐88) and in circulation (MPO+//Ly6C+/CD11b+//Ly6G+/CD11b+) exhibited an identical pattern, whereas the neurological function displayed an opposite pattern of inflammatory protein expression among the six groups (all P < .0001). In conclusion, TLR inflammatory and oxidative stress signallings played crucial roles for brain damage and impaired neurological function after IS that were significantly reversed by Mel therapy.
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Affiliation(s)
- Kuan-Hung Chen
- Department of Anesthesiology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Kun-Chen Lin
- Department of Anesthesiology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Sheung-Fat Ko
- Department of Radiology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - John Y Chiang
- Department of Computer Science and Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Jun Guo
- Department of Cardiology, The First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Hon-Kan Yip
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.,Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.,Center for Shockwave Medicine and Tissue Engineering, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.,Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan.,Department of Nursing, Asia University, Taichung, Taiwan.,Division of Cardiology, Department of Internal Medicine, Xiamen Chang Gung Hospital, Fujian, China
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