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Wellford SA, Moseman EA. Olfactory immunology: the missing piece in airway and CNS defence. Nat Rev Immunol 2024; 24:381-398. [PMID: 38097777 DOI: 10.1038/s41577-023-00972-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2023] [Indexed: 12/23/2023]
Abstract
The olfactory mucosa is a component of the nasal airway that mediates the sense of smell. Recent studies point to an important role for the olfactory mucosa as a barrier to both respiratory pathogens and to neuroinvasive pathogens that hijack the olfactory nerve and invade the CNS. In particular, the COVID-19 pandemic has demonstrated that the olfactory mucosa is an integral part of a heterogeneous nasal mucosal barrier critical to upper airway immunity. However, our insufficient knowledge of olfactory mucosal immunity hinders attempts to protect this tissue from infection and other diseases. This Review summarizes the state of olfactory immunology by highlighting the unique immunologically relevant anatomy of the olfactory mucosa, describing what is known of olfactory immune cells, and considering the impact of common infectious diseases and inflammatory disorders at this site. We will offer our perspective on the future of the field and the many unresolved questions pertaining to olfactory immunity.
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Affiliation(s)
- Sebastian A Wellford
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA
| | - E Ashley Moseman
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA.
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2
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Chen X, Liu Y, Stavrinou P, Stavrinou L, Hu W, Goldbrunner R, Zheng F, He H. Spinal cord injury: Olfactory ensheathing cell-based therapeutic strategies. J Neurosci Res 2024; 102:e25283. [PMID: 38284859 DOI: 10.1002/jnr.25283] [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: 03/25/2023] [Revised: 08/22/2023] [Accepted: 11/16/2023] [Indexed: 01/30/2024]
Abstract
Spinal cord injury (SCI) is a highly disabling neurological disorder that is difficult to treat due to its complex pathophysiology and nerve regeneration difficulties. Hence, effective SCI treatments are necessary. Olfactory ensheathing cells (OECs), glial cells derived from the olfactory bulb or mucosa, are ideal candidates for SCI treatment because of their neuroprotective and regenerative properties, ample supply, and convenience. In vitro, animal model, and human trial studies have reported discoveries on OEC transplantation; however, shortcomings have also been demonstrated. Recent studies have optimized various OEC transplantation strategies, including drug integration, biomaterials, and gene editing. This review aims to introduce OECs mechanisms in repairing SCI, summarize the research progress of OEC transplantation-optimized strategies, and provide novel research ideas for SCI treatment.
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Affiliation(s)
- Xinli Chen
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - Yibin Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - Pantelis Stavrinou
- Department of Neurosurgery, Center for Neurosurgery, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany
- Neurosurgery, Metropolitan Hospital, Athens, Greece
| | - Lampis Stavrinou
- 2nd Department of Neurosurgery, "Attikon" University Hospital, National and Kapodistrian University, Athens Medical School, Athens, Greece
| | - Weipeng Hu
- Department of Neurosurgery, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - Roland Goldbrunner
- Department of Neurosurgery, Center for Neurosurgery, Faculty of Medicine and University Hospital, University of Cologne, Cologne, Germany
| | - Feng Zheng
- Department of Neurosurgery, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - Hefan He
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
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3
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Merle DA, Sen M, Armento A, Stanton CM, Thee EF, Meester-Smoor MA, Kaiser M, Clark SJ, Klaver CCW, Keane PA, Wright AF, Ehrmann M, Ueffing M. 10q26 - The enigma in age-related macular degeneration. Prog Retin Eye Res 2023; 96:101154. [PMID: 36513584 DOI: 10.1016/j.preteyeres.2022.101154] [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: 09/14/2022] [Revised: 11/21/2022] [Accepted: 12/01/2022] [Indexed: 12/14/2022]
Abstract
Despite comprehensive research efforts over the last decades, the pathomechanisms of age-related macular degeneration (AMD) remain far from being understood. Large-scale genome wide association studies (GWAS) were able to provide a defined set of genetic aberrations which contribute to disease risk, with the strongest contributors mapping to distinct regions on chromosome 1 and 10. While the chromosome 1 locus comprises factors of the complement system with well-known functions, the role of the 10q26-locus in AMD-pathophysiology remains enigmatic. 10q26 harbors a cluster of three functional genes, namely PLEKHA1, ARMS2 and HTRA1, with most of the AMD-associated genetic variants mapping to the latter two genes. High linkage disequilibrium between ARMS2 and HTRA1 has kept association studies from reliably defining the risk-causing gene for long and only very recently the genetic risk region has been narrowed to ARMS2, suggesting that this is the true AMD gene at this locus. However, genetic associations alone do not suffice to prove causality and one or more of the 14 SNPs on this haplotype may be involved in long-range control of gene expression, leaving HTRA1 and PLEKHA1 still suspects in the pathogenic pathway. Both, ARMS2 and HTRA1 have been linked to extracellular matrix homeostasis, yet their exact molecular function as well as their role in AMD pathogenesis remains to be uncovered. The transcriptional regulation of the 10q26 locus adds an additional level of complexity, given, that gene-regulatory as well as epigenetic alterations may influence expression levels from 10q26 in diseased individuals. Here, we provide a comprehensive overview on the 10q26 locus and its three gene products on various levels of biological complexity and discuss current and future research strategies to shed light on one of the remaining enigmatic spots in the AMD landscape.
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Affiliation(s)
- David A Merle
- Institute for Ophthalmic Research, Department for Ophthalmology, Eberhard Karls University of Tübingen, 72076, Tübingen, Germany; Department for Ophthalmology, University Eye Clinic, Eberhard Karls University of Tübingen, 72076, Tübingen, Germany; Department of Ophthalmology, Medical University of Graz, 8036, Graz, Austria.
| | - Merve Sen
- Institute for Ophthalmic Research, Department for Ophthalmology, Eberhard Karls University of Tübingen, 72076, Tübingen, Germany
| | - Angela Armento
- Institute for Ophthalmic Research, Department for Ophthalmology, Eberhard Karls University of Tübingen, 72076, Tübingen, Germany
| | - Chloe M Stanton
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Eric F Thee
- Department of Ophthalmology, Erasmus University Medical Center, 3015GD, Rotterdam, Netherlands; Department of Epidemiology, Erasmus University Medical Center, 3015CE, Rotterdam, Netherlands
| | - Magda A Meester-Smoor
- Department of Ophthalmology, Erasmus University Medical Center, 3015GD, Rotterdam, Netherlands; Department of Epidemiology, Erasmus University Medical Center, 3015CE, Rotterdam, Netherlands
| | - Markus Kaiser
- Center of Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, 45117, Essen, Germany
| | - Simon J Clark
- Institute for Ophthalmic Research, Department for Ophthalmology, Eberhard Karls University of Tübingen, 72076, Tübingen, Germany; Department for Ophthalmology, University Eye Clinic, Eberhard Karls University of Tübingen, 72076, Tübingen, Germany; Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Caroline C W Klaver
- Department of Ophthalmology, Erasmus University Medical Center, 3015GD, Rotterdam, Netherlands; Department of Epidemiology, Erasmus University Medical Center, 3015CE, Rotterdam, Netherlands; Department of Ophthalmology, Radboudumc, 6525EX, Nijmegen, Netherlands; Institute of Molecular and Clinical Ophthalmology Basel, CH-4031, Basel, Switzerland
| | - Pearse A Keane
- Institute for Health Research, Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust, UCL Institute of Ophthalmology, London, EC1V 2PD, UK
| | - Alan F Wright
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Michael Ehrmann
- Center of Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, 45117, Essen, Germany
| | - Marius Ueffing
- Institute for Ophthalmic Research, Department for Ophthalmology, Eberhard Karls University of Tübingen, 72076, Tübingen, Germany; Department for Ophthalmology, University Eye Clinic, Eberhard Karls University of Tübingen, 72076, Tübingen, Germany.
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4
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Denaro S, D’Aprile S, Alberghina C, Pavone AM, Torrisi F, Giallongo S, Longhitano L, Mannino G, Lo Furno D, Zappalà A, Giuffrida R, Tibullo D, Li Volti G, Vicario N, Parenti R. Neurotrophic and immunomodulatory effects of olfactory ensheathing cells as a strategy for neuroprotection and regeneration. Front Immunol 2022; 13:1098212. [PMID: 36601122 PMCID: PMC9806219 DOI: 10.3389/fimmu.2022.1098212] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022] Open
Abstract
Accumulating evidence sustains glial cells as critical players during central nervous system (CNS) development, homeostasis and disease. Olfactory ensheathing cells (OECs), a type of specialized glia cells sharing properties with both Schwann cells and astrocytes, are of critical importance in physiological condition during olfactory system development, supporting its regenerative potential throughout the adult life. These characteristics prompted research in the field of cell-based therapy to test OEC grafts in damaged CNS. Neuroprotective mechanisms exerted by OEC grafts are not limited to axonal regeneration and cell differentiation. Indeed, OEC immunomodulatory properties and their phagocytic potential encourage OEC-based approaches for tissue regeneration in case of CNS injury. Herein we reviewed recent advances on the immune role of OECs, their ability to modulate CNS microenvironment via bystander effects and the potential of OECs as a cell-based strategy for tissue regeneration.
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Affiliation(s)
- Simona Denaro
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Simona D’Aprile
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Cristiana Alberghina
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Anna Maria Pavone
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Filippo Torrisi
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Sebastiano Giallongo
- Section of Biochemistry, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Lucia Longhitano
- Section of Biochemistry, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Giuliana Mannino
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Debora Lo Furno
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Agata Zappalà
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Rosario Giuffrida
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Daniele Tibullo
- Section of Biochemistry, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Giovanni Li Volti
- Section of Biochemistry, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Nunzio Vicario
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy,*Correspondence: Nunzio Vicario, ; Rosalba Parenti,
| | - Rosalba Parenti
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy,*Correspondence: Nunzio Vicario, ; Rosalba Parenti,
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5
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Designing a Clinical Trial with Olfactory Ensheathing Cell Transplantation-Based Therapy for Spinal Cord Injury: A Position Paper. Biomedicines 2022; 10:biomedicines10123153. [PMID: 36551909 PMCID: PMC9776288 DOI: 10.3390/biomedicines10123153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/29/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022] Open
Abstract
Spinal cord injury (SCI) represents an urgent unmet need for clinical reparative therapy due to its largely irreversible and devastating effects on patients, and the tremendous socioeconomic burden to the community. While different approaches are being explored, therapy to restore the lost function remains unavailable. Olfactory ensheathing cell (OEC) transplantation is a promising approach in terms of feasibility, safety, and limited efficacy; however, high variability in reported clinical outcomes prevent its translation despite several clinical trials. The aims of this position paper are to present an in-depth analysis of previous OEC transplantation-based clinical trials, identify existing challenges and gaps, and finally propose strategies to improve standardization of OEC therapies. We have reviewed the study design and protocols of clinical trials using OEC transplantation for SCI repair to investigate how and why the outcomes show variability. With this knowledge and our experience as a team of biologists and clinicians with active experience in the field of OEC research, we provide recommendations regarding cell source, cell purity and characterisation, transplantation dosage and format, and rehabilitation. Ultimately, this position paper is intended to serve as a roadmap to design an effective clinical trial with OEC transplantation-based therapy for SCI repair.
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Basu S, Choudhury IN, Lee JYP, Chacko A, Ekberg JAK, St John JA. Macrophages Treated with VEGF and PDGF Exert Paracrine Effects on Olfactory Ensheathing Cell Function. Cells 2022; 11:cells11152408. [PMID: 35954252 PMCID: PMC9368560 DOI: 10.3390/cells11152408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 02/05/2023] Open
Abstract
Glial cell transplantation using olfactory ensheathing cells (OECs) holds a promising approach for treating spinal cord injury (SCI). However, integration of OECs into the hostile acute secondary injury site requires interaction and response to macrophages. Immunomodulation of macrophages to reduce their impact on OECs may improve the functionality of OECs. Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF), known for their immunomodulatory and neuroprotective functions, have provided improved outcomes in SCI animal models. Thus, VEGF and PDGF modulation of the SCI microenvironment may be beneficial for OEC transplantation. In this in vitro study, the effect of VEGF and PDGF on macrophages in an inflammatory condition was tested. Combined VEGF + PDGF reduced translocation nuclear factor kappa B p65 in macrophages without altering pro-inflammatory cytokines. Further, the ability of OECs to phagocytose myelin debris was assessed using macrophage-conditioned medium. Conditioned medium from macrophages incubated with PDGF and combined VEGF + PDGF in inflammatory conditions promoted phagocytosis by OECs. The growth factor treated conditioned media also modulated the expression of genes associated with nerve repair and myelin expression in OECs. Overall, these results suggest that the use of growth factors together with OEC transplantation may be beneficial in SCI therapy.
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Affiliation(s)
- Souptik Basu
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
- Menzies Health Institute Queensland, Southport Campus, Griffith University, Southport, QLD 4222, Australia
| | - Indra N. Choudhury
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
- Menzies Health Institute Queensland, Southport Campus, Griffith University, Southport, QLD 4222, Australia
| | - Jia Yu Peppermint Lee
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
| | - Anu Chacko
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
- Menzies Health Institute Queensland, Southport Campus, Griffith University, Southport, QLD 4222, Australia
| | - Jenny A. K. Ekberg
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
- Menzies Health Institute Queensland, Southport Campus, Griffith University, Southport, QLD 4222, Australia
- Griffith Institute for Drug Discovery, Nathan Campus, Griffith University, Nathan, QLD 4111, Australia
| | - James A. St John
- Clem Jones Centre for Neurobiology and Stem Cell Research, Nathan Campus, Griffith University, Nathan, QLD 4222, Australia
- Menzies Health Institute Queensland, Southport Campus, Griffith University, Southport, QLD 4222, Australia
- Griffith Institute for Drug Discovery, Nathan Campus, Griffith University, Nathan, QLD 4111, Australia
- Correspondence:
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7
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Song S, Xiao Z, Dekker FJ, Poelarends GJ, Melgert BN. Macrophage migration inhibitory factor family proteins are multitasking cytokines in tissue injury. Cell Mol Life Sci 2022; 79:105. [PMID: 35091838 PMCID: PMC8799543 DOI: 10.1007/s00018-021-04038-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/10/2021] [Accepted: 11/12/2021] [Indexed: 02/06/2023]
Abstract
The family of macrophage migration inhibitory factor (MIF) proteins in humans consist of MIF, its functional homolog D-dopachrome tautomerase (D-DT, also known as MIF-2) and the relatively unknown protein named DDT-like (DDTL). MIF is a pleiotropic cytokine with multiple properties in tissue homeostasis and pathology. MIF was initially found to associate with inflammatory responses and therefore established a reputation as a pro-inflammatory cytokine. However, increasing evidence demonstrates that MIF influences many different intra- and extracellular molecular processes important for the maintenance of cellular homeostasis, such as promotion of cellular survival, antioxidant signaling, and wound repair. In contrast, studies on D-DT are scarce and on DDTL almost nonexistent and their functions remain to be further investigated as it is yet unclear how similar they are compared to MIF. Importantly, the many and sometimes opposing functions of MIF suggest that targeting MIF therapeutically should be considered carefully, taking into account timing and severity of tissue injury. In this review, we focus on the latest discoveries regarding the role of MIF family members in tissue injury, inflammation and repair, and highlight the possibilities of interventions with therapeutics targeting or mimicking MIF family proteins.
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Flack JA, Sharma KD, Xie JY. Delving into the recent advancements of spinal cord injury treatment: a review of recent progress. Neural Regen Res 2022; 17:283-291. [PMID: 34269189 PMCID: PMC8463999 DOI: 10.4103/1673-5374.317961] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Spinal cord injury (SCI) research is a very complex field lending to why reviews of SCI literatures can be beneficial to current and future researchers. This review focuses on recent articles regarding potential modalities for the treatment and management of SCI. The modalities were broken down into four categories: neuroprotection-pharmacologic, neuroprotection-non-pharmacologic, neuroregeneration-pharmacologic, neuroregeneration-non-pharmacologic. Peer-reviewed articles were found using PubMed with search terms: "spinal cord injury", "spinal cord injury neuroregeneration", "olfactory ensheathing cells spinal cord injury", "rho-rock inhibitors spinal cord injury", "neural stem cell", "scaffold", "neural stem cell transplantation", "exosomes and SCI", "epidural stimulation SCI", "brain-computer interfaces and SCI". Most recent articles spanning two years were chosen for their relevance to the categories of SCI management and treatment. There has been a plethora of pre-clinical studies completed with their results being difficult to replicate in clinical studies. Therefore, scientists should focus on understanding and applying the results of previous research to develop more efficacious preclinical studies and clinical trials.
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Affiliation(s)
- Joseph A Flack
- Department of Basic Sciences, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR, USA
| | - Krishna Deo Sharma
- Department of Biological Sciences and Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR, USA
| | - Jennifer Yanhua Xie
- Department of Basic Sciences, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR, USA
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Gilmour AD, Reshamwala R, Wright AA, Ekberg JAK, St John JA. Optimizing Olfactory Ensheathing Cell Transplantation for Spinal Cord Injury Repair. J Neurotrauma 2021; 37:817-829. [PMID: 32056492 DOI: 10.1089/neu.2019.6939] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cell transplantation constitutes an important avenue for development of new treatments for spinal cord injury (SCI). These therapies are aimed at supporting neural repair and/or replacing lost cells at the injury site. To date, various cell types have been trialed, with most studies focusing on different types of stem cells or glial cells. Here, we review commonly used cell transplantation approaches for spinal cord injury (SCI) repair, with focus on transplantation of olfactory ensheathing cells (OECs), the glial cells of the primary olfactory nervous system. OECs are promising candidates for promotion of neural repair given that they support continuous regeneration of the olfactory nerve that occurs throughout life. Further, OECs can be accessed from the nasal mucosa (olfactory neuroepithelium) at the roof of the nasal cavity and can be autologously transplanted. OEC transplantation has been trialed in many animal models of SCI, as well as in human clinical trials. While several studies have been promising, outcomes are variable and the method needs improvement to enhance aspects such as cell survival, integration, and migration. As a case study, we include the approaches used by our team (the Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia) to address the current problems with OEC transplantation and discuss how the therapeutic potential of OEC transplantation can be improved. Our approach includes discovery research to improve our knowledge of OEC biology, identifying natural and synthetic compounds to stimulate the neural repair properties of OECs, and designing three-dimensional cell constructs to create stable and transplantable cell structures.
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Affiliation(s)
- Aaron D Gilmour
- Clem Jones Centre for Neurobiology and Stem Cell Research and Griffith University, Nathan, Queensland, Australia.,Menzies Health Institute Queensland, Griffith University, Southport, Queensland, Australia
| | - Ronak Reshamwala
- Clem Jones Centre for Neurobiology and Stem Cell Research and Griffith University, Nathan, Queensland, Australia.,Menzies Health Institute Queensland, Griffith University, Southport, Queensland, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - Alison A Wright
- Clem Jones Centre for Neurobiology and Stem Cell Research and Griffith University, Nathan, Queensland, Australia.,Menzies Health Institute Queensland, Griffith University, Southport, Queensland, Australia
| | - Jenny A K Ekberg
- Clem Jones Centre for Neurobiology and Stem Cell Research and Griffith University, Nathan, Queensland, Australia.,Menzies Health Institute Queensland, Griffith University, Southport, Queensland, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - James A St John
- Clem Jones Centre for Neurobiology and Stem Cell Research and Griffith University, Nathan, Queensland, Australia.,Menzies Health Institute Queensland, Griffith University, Southport, Queensland, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
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10
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Nazareth L, St John J, Murtaza M, Ekberg J. Phagocytosis by Peripheral Glia: Importance for Nervous System Functions and Implications in Injury and Disease. Front Cell Dev Biol 2021; 9:660259. [PMID: 33898462 PMCID: PMC8060502 DOI: 10.3389/fcell.2021.660259] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/17/2021] [Indexed: 12/30/2022] Open
Abstract
The central nervous system (CNS) has very limited capacity to regenerate after traumatic injury or disease. In contrast, the peripheral nervous system (PNS) has far greater capacity for regeneration. This difference can be partly attributed to variances in glial-mediated functions, such as axon guidance, structural support, secretion of growth factors and phagocytic activity. Due to their growth-promoting characteristic, transplantation of PNS glia has been trialed for neural repair. After peripheral nerve injuries, Schwann cells (SCs, the main PNS glia) phagocytose myelin debris and attract macrophages to the injury site to aid in debris clearance. One peripheral nerve, the olfactory nerve, is unique in that it continuously regenerates throughout life. The olfactory nerve glia, olfactory ensheathing cells (OECs), are the primary phagocytes within this nerve, continuously clearing axonal debris arising from the normal regeneration of the nerve and after injury. In contrast to SCs, OECs do not appear to attract macrophages. SCs and OECs also respond to and phagocytose bacteria, a function likely critical for tackling microbial invasion of the CNS via peripheral nerves. However, phagocytosis is not always effective; inflammation, aging and/or genetic factors may contribute to compromised phagocytic activity. Here, we highlight the diverse roles of SCs and OECs with the focus on their phagocytic activity under physiological and pathological conditions. We also explore why understanding the contribution of peripheral glia phagocytosis may provide us with translational strategies for achieving axonal regeneration of the injured nervous system and potentially for the treatment of certain neurological diseases.
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Affiliation(s)
- Lynn Nazareth
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia
| | - James St John
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Mariyam Murtaza
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
| | - Jenny Ekberg
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.,Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD, Australia
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11
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Key differences between olfactory ensheathing cells and Schwann cells regarding phagocytosis of necrotic cells: implications for transplantation therapies. Sci Rep 2020; 10:18936. [PMID: 33144615 PMCID: PMC7642263 DOI: 10.1038/s41598-020-75850-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/19/2020] [Indexed: 12/12/2022] Open
Abstract
Transplantation of peripheral nervous system glia is being explored for treating neural injuries, in particular central nervous system injuries. These glia, olfactory ensheathing cells (OECs) and Schwann cells (SCs), are thought to aid regeneration by clearing necrotic cells, (necrotic bodies, NBs), as well as myelin debris. The mechanism by which the glia phagocytose and traffic NBs are not understood. Here, we show that OECs and SCs recognize phosphatidylserine on NBs, followed by engulfment and trafficking to endosomes and lysosomes. We also showed that both glia can phagocytose and process myelin debris. We compared the time-course of glial phagocytosis (of both NBs and myelin) to that of macrophages. Internalization and trafficking were considerably slower in glia than in macrophages, and OECs were more efficient phagocytes than SCs. The two glial types also differed regarding their cytokine responses after NB challenge. SCs produced low amounts of the pro-inflammatory cytokine TNF-α while OECs did not produce detectable TNF-α. Thus, OECs have a higher capacity than SCs for phagocytosis and trafficking, whilst producing lower amounts of pro-inflammatory cytokines. These findings suggest that OEC transplantation into the injured nervous system may lead to better outcomes than SC transplantation.
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