1
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Gupta DP, Bhusal A, Rahman MH, Kim JH, Choe Y, Jang J, Jung HJ, Kim UK, Park JS, Maeng LS, Suk K, Song GJ. EBP50 is a key molecule for the Schwann cell-axon interaction in peripheral nerves. Prog Neurobiol 2023; 231:102544. [PMID: 37940033 DOI: 10.1016/j.pneurobio.2023.102544] [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: 04/11/2023] [Revised: 10/25/2023] [Accepted: 11/02/2023] [Indexed: 11/10/2023]
Abstract
Peripheral nerve injury disrupts the Schwann cell-axon interaction and the cellular communication between them. The peripheral nervous system has immense potential for regeneration extensively due to the innate plastic potential of Schwann cells (SCs) that allows SCs to interact with the injured axons and exert specific repair functions essential for peripheral nerve regeneration. In this study, we show that EBP50 is essential for the repair function of SCs and regeneration following nerve injury. The increased expression of EBP50 in the injured sciatic nerve of control mice suggested a significant role in regeneration. The ablation of EBP50 in mice resulted in delayed nerve repair, recovery of behavioral function, and remyelination following nerve injury. EBP50 deficiency led to deficits in SC functions, including proliferation, migration, cytoskeleton dynamics, and axon interactions. The adeno-associated virus (AAV)-mediated local expression of EBP50 improved SCs migration, functional recovery, and remyelination. ErbB2-related proteins were not differentially expressed in EBP50-deficient sciatic nerves following injury. EBP50 binds and stabilizes ErbB2 and activates the repair functions to promote regeneration. Thus, we identified EBP50 as a potent SC protein that can enhance the regeneration and functional recovery driven by NRG1-ErbB2 signaling, as well as a novel regeneration modulator capable of potential therapeutic effects.
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Affiliation(s)
- Deepak Prasad Gupta
- Translational Brain Research Center, International St. Mary's Hospital, Catholic Kwandong University, Incheon, Republic of Korea; Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Anup Bhusal
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Md Habibur Rahman
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Jae-Hong Kim
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Youngshik Choe
- Korea Brain Research Institute, Daegu, Republic of Korea
| | - Jaemyung Jang
- Korea Brain Research Institute, Daegu, Republic of Korea
| | - Hyun Jin Jung
- Korea Brain Research Institute, Daegu, Republic of Korea
| | - Un-Kyung Kim
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Jin-Sung Park
- Department of Neurology, School of Medicine, Kyungpook National University, Kyungpook National University Chilgok Hospital, Daegu, Republic of Korea
| | - Lee-So Maeng
- Department of Hospital Pathology, Incheon St. Mary's Hospital College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Kyoungho Suk
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Gyun Jee Song
- Translational Brain Research Center, International St. Mary's Hospital, Catholic Kwandong University, Incheon, Republic of Korea; Department of Medicine, College of Medicine, Catholic Kwandong University, Gangneung, Gangwon-do, Republic of Korea.
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2
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Chen O, Luo X, Ji RR. Macrophages and microglia in inflammation and neuroinflammation underlying different pain states. MEDICAL REVIEW (2021) 2023; 3:381-407. [PMID: 38283253 PMCID: PMC10811354 DOI: 10.1515/mr-2023-0034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/26/2023] [Indexed: 01/30/2024]
Abstract
Pain is a main symptom in inflammation, and inflammation induces pain via inflammatory mediators acting on nociceptive neurons. Macrophages and microglia are distinct cell types, representing immune cells and glial cells, respectively, but they share similar roles in pain regulation. Macrophages are key regulators of inflammation and pain. Macrophage polarization plays different roles in inducing and resolving pain. Notably, macrophage polarization and phagocytosis can be induced by specialized pro-resolution mediators (SPMs). SPMs also potently inhibit inflammatory and neuropathic pain via immunomodulation and neuromodulation. In this review, we discuss macrophage signaling involved in pain induction and resolution, as well as in maintaining physiological pain. Microglia are macrophage-like cells in the central nervous system (CNS) and drive neuroinflammation and pathological pain in various inflammatory and neurological disorders. Microglia-produced inflammatory cytokines can potently regulate excitatory and inhibitory synaptic transmission as neuromodulators. We also highlight sex differences in macrophage and microglial signaling in inflammatory and neuropathic pain. Thus, targeting macrophage and microglial signaling in distinct locations via pharmacological approaches, including immunotherapies, and non-pharmacological approaches will help to control chronic inflammation and chronic pain.
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Affiliation(s)
- Ouyang Chen
- Department of Anesthesiology, Center for Translational Pain Medicine, Duke University Medical Center, Durham, NC, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
| | - Xin Luo
- Department of Anesthesiology, Center for Translational Pain Medicine, Duke University Medical Center, Durham, NC, USA
- Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Ru-Rong Ji
- Department of Anesthesiology, Center for Translational Pain Medicine, Duke University Medical Center, Durham, NC, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC, USA
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3
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McGinnis A, Ji RR. The Similar and Distinct Roles of Satellite Glial Cells and Spinal Astrocytes in Neuropathic Pain. Cells 2023; 12:965. [PMID: 36980304 PMCID: PMC10047571 DOI: 10.3390/cells12060965] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 03/19/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Preclinical studies have identified glial cells as pivotal players in the genesis and maintenance of neuropathic pain after nerve injury associated with diabetes, chemotherapy, major surgeries, and virus infections. Satellite glial cells (SGCs) in the dorsal root and trigeminal ganglia of the peripheral nervous system (PNS) and astrocytes in the central nervous system (CNS) express similar molecular markers and are protective under physiological conditions. They also serve similar functions in the genesis and maintenance of neuropathic pain, downregulating some of their homeostatic functions and driving pro-inflammatory neuro-glial interactions in the PNS and CNS, i.e., "gliopathy". However, the role of SGCs in neuropathic pain is not simply as "peripheral astrocytes". We delineate how these peripheral and central glia participate in neuropathic pain by producing different mediators, engaging different parts of neurons, and becoming active at different stages following nerve injury. Finally, we highlight the recent findings that SGCs are enriched with proteins related to fatty acid metabolism and signaling such as Apo-E, FABP7, and LPAR1. Targeting SGCs and astrocytes may lead to novel therapeutics for the treatment of neuropathic pain.
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Affiliation(s)
- Aidan McGinnis
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ru-Rong Ji
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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4
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Schwann cell functions in peripheral nerve development and repair. Neurobiol Dis 2023; 176:105952. [PMID: 36493976 DOI: 10.1016/j.nbd.2022.105952] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/23/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022] Open
Abstract
The glial cell of the peripheral nervous system (PNS), the Schwann cell (SC), counts among the most multifaceted cells of the body. During development, SCs secure neuronal survival and participate in axonal path finding. Simultaneously, they orchestrate the architectural set up of the developing nerves, including the blood vessels and the endo-, peri- and epineurial layers. Perinatally, in rodents, SCs radially sort and subsequently myelinate individual axons larger than 1 μm in diameter, while small calibre axons become organised in non-myelinating Remak bundles. SCs have a vital role in maintaining axonal health throughout life and several specialized SC types perform essential functions at specific locations, such as terminal SC at the neuromuscular junction (NMJ) or SC within cutaneous sensory end organs. In addition, neural crest derived satellite glia maintain a tight communication with the soma of sensory, sympathetic, and parasympathetic neurons and neural crest derivatives are furthermore an indispensable part of the enteric nervous system. The remarkable plasticity of SCs becomes evident in the context of a nerve injury, where SC transdifferentiate into intriguing repair cells, which orchestrate a regenerative response that promotes nerve repair. Indeed, the multiple adaptations of SCs are captivating, but remain often ill-resolved on the molecular level. Here, we summarize and discuss the knowns and unknowns of the vast array of functions that this single cell type can cover in peripheral nervous system development, maintenance, and repair.
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Deborde S, Wong RJ. The Role of Schwann Cells in Cancer. Adv Biol (Weinh) 2022; 6:e2200089. [PMID: 35666078 PMCID: PMC9474572 DOI: 10.1002/adbi.202200089] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/14/2022] [Indexed: 01/28/2023]
Abstract
Schwann cells (SCs) are the most abundant cell type in the nerves in the peripheral nervous system and compose a family of subtypes that are endowed with a variety of different functions. SCs facilitate the transmission of neural impulses, provide nutrients and protection for neurons, guide axons in nerve repair, and regulate immune functions. In the context of cancer, recent studies have revealed an active role of SCs in promoting cancer cell invasion, modulating immune responses, and transmitting pain sensation.
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Affiliation(s)
- Sylvie Deborde
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Richard J Wong
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
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Zheng Q, Dong X, Green DP, Dong X. Peripheral mechanisms of chronic pain. MEDICAL REVIEW 2022; 2:251-270. [PMID: 36067122 PMCID: PMC9381002 DOI: 10.1515/mr-2022-0013] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 06/13/2022] [Indexed: 11/15/2022]
Abstract
Abstract
Acutely, pain serves to protect us from potentially harmful stimuli, however damage to the somatosensory system can cause maladaptive changes in neurons leading to chronic pain. Although acute pain is fairly well controlled, chronic pain remains difficult to treat. Chronic pain is primarily a neuropathic condition, but studies examining the mechanisms underlying chronic pain are now looking beyond afferent nerve lesions and exploring new receptor targets, immune cells, and the role of the autonomic nervous system in contributing chronic pain conditions. The studies outlined in this review reveal how chronic pain is not only confined to alterations in the nervous system and presents findings on new treatment targets and for this debilitating disease.
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Affiliation(s)
- Qin Zheng
- Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Xintong Dong
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Dustin P. Green
- Department of Neuroscience, Cell Biology, and Anatomy, University of Texas Medical Branch, Galveston, TX, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Howard Hughes Medical Institute, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
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7
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Özdağ Acarli AN, Klein T, Egenolf N, Sommer C, Üçeyler N. Subepidermal Schwann cell counts correlate with skin innervation - an exploratory study. Muscle Nerve 2022; 65:471-479. [PMID: 35020203 DOI: 10.1002/mus.27496] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 01/05/2022] [Accepted: 01/05/2022] [Indexed: 11/10/2022]
Abstract
INTRODUCTION/AIMS Schwann cell clusters have been described at the murine dermis-epidermis border. We quantified dermal Schwann cells in the skin of patients with small fiber neuropathy (SFN) compared to healthy controls to correlate with the clinical phenotype. METHODS Skin punch biopsies from the lower legs of 28 patients with SFN (eleven men, 17 women, median age 54 years [19-73]) and 9 healthy controls (five men, four women, median age 34 years [25-69]) were immunoreacted for S100 calcium-binding protein B as a Schwann cell marker, protein-gene product 9.5 as a pan-neuronal marker, and CD207 as a Langerhans cell marker. Intraepidermal nerve fiber density (IENFD) and subepidermal Schwann cell counts were determined. RESULTS Skin samples of patients with SFN showed lower IENFD (p<0.05), fewer Schwann cells/mm (p<0.01), and fewer Schwann cell clusters/mm (p<0.05) than controls. When comparing SFN patients with reduced (n=13, median age 53 years, 19-73 years) and normal distal (n=15, median age 54 years, 43-68 years) IENFD, the number of solitary Schwann cells/mm (p<0.01) and subepidermal nerve fibers associated with Schwann cell branches (p<0.05) were lower in patients with reduced IENFD. All three parameters positively correlated with distal IENFD (p<0.05 to p<0.01), while no correlation was found between Schwann cell counts and clinical pain characteristics. DISCUSSION Our data raise questions about the mechanisms underlying the interdependence of dermal Schwann cells and skin innervation in SFN. The temporal course and functional impact of Schwann cell presence and kinetics need further investigation.
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Affiliation(s)
| | - Thomas Klein
- Department of Neurology, University of Würzburg, Germany
| | - Nadine Egenolf
- Department of Neurology, University of Würzburg, Germany
| | - Claudia Sommer
- Department of Neurology, University of Würzburg, Germany
| | - Nurcan Üçeyler
- Department of Neurology, University of Würzburg, Germany
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8
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Follis RM, Tep C, Genaro-Mattos TC, Kim ML, Ryu JC, Morrison VE, Chan JR, Porter N, Carter BD, Yoon SO. Metabolic Control of Sensory Neuron Survival by the p75 Neurotrophin Receptor in Schwann Cells. J Neurosci 2021; 41:8710-8724. [PMID: 34507952 PMCID: PMC8528492 DOI: 10.1523/jneurosci.3243-20.2021] [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: 12/31/2020] [Revised: 08/28/2021] [Accepted: 08/30/2021] [Indexed: 11/21/2022] Open
Abstract
We report that the neurotrophin receptor p75 contributes to sensory neuron survival through the regulation of cholesterol metabolism in Schwann cells. Selective deletion of p75 in mouse Schwann cells of either sex resulted in a 30% loss of dorsal root ganglia (DRG) neurons and diminished thermal sensitivity. P75 regulates Schwann cell cholesterol biosynthesis in response to BDNF, forming a co-receptor complex with ErbB2 and activating ErbB2-mediated stimulation of sterol regulatory element binding protein 2 (SREBP2), a master regulator of cholesterol synthesis. Schwann cells lacking p75 exhibited decreased activation of SREBP2 and a reduction in 7-dehydrocholesterol (7-DHC) reductase (DHCR7) expression, resulting in accumulation of the neurotoxic intermediate, 7-dehyrocholesterol in the sciatic nerve. Restoration of DHCR7 in p75 null Schwann cells in mice significantly attenuated DRG neuron loss. Together, these results reveal a mechanism by which the disruption of lipid metabolism in glial cells negatively influences sensory neuron survival, which has implications for a wide range of peripheral neuropathies.SIGNIFICANCE STATEMENT Although expressed in Schwann cells, the role of p75 in myelination has remained unresolved in part because of its dual expression in sensory neurons that Schwann cells myelinate. When p75 was deleted selectively among Schwann cells, myelination was minimally affected, while sensory neuron survival was reduced by 30%. The phenotype is mainly due to dysregulation of cholesterol biosynthesis in p75-deficient Schwann cells, leading to an accumulation of neurotoxic cholesterol precursor, 7-dehydrocholesterol (7-DHC). Mechanism-wise, we discovered that in response to BDNF, p75 recruits and activates ErbB2 independently of ErbB3, thereby stimulating the master regulator, sterol regulatory element binding protein 2 (SREBP2). These results together highlight a novel role of p75 in Schwann cells in regulating DRG neuron survival by orchestrating proper cholesterol metabolism.
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Affiliation(s)
- Rose M Follis
- Department of Biochemistry, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Chhavy Tep
- Department of Biological Chemistry and Pharmacology, Ohio State University, Columbus, Ohio
| | - Thiago C Genaro-Mattos
- Department of Chemistry, Vanderbilt University School of Arts and Sciences, Nashville, Tennessee 37232
| | - Mi Lyang Kim
- Department of Biological Chemistry and Pharmacology, Ohio State University, Columbus, Ohio
| | - Jae Cheon Ryu
- Department of Biological Chemistry and Pharmacology, Ohio State University, Columbus, Ohio
| | - Vivianne E Morrison
- Department of Biochemistry, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Jonah R Chan
- Department of Neurology, University of California San Francisco, San Francisco, California 94158
| | - Ned Porter
- Department of Chemistry, Vanderbilt University School of Arts and Sciences, Nashville, Tennessee 37232
| | - Bruce D Carter
- Department of Biochemistry, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Sung Ok Yoon
- Department of Biological Chemistry and Pharmacology, Ohio State University, Columbus, Ohio
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Forouzanfar F, Sadeghnia HR. Fibroblast Growth Factors as Tools in the Management of Neuropathic Pain Disorders. Curr Drug Targets 2021; 21:1034-1043. [PMID: 32324511 DOI: 10.2174/1389450121666200423084205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/22/2020] [Accepted: 01/24/2020] [Indexed: 12/19/2022]
Abstract
Neuropathic pain is caused by a damage to or dysfunction of the somatosensory nervous system. The main mechanisms underlying neuropathic pain include ectopic activity in nociceptive nerves, peripheral and central sensitization, impaired inhibitory modulation, and microglial activation. Fibroblast growth factors (FGFs) make up a large family of growth factors that mediate neural development, metabolism, and function through three main key signaling pathways, including RAS/MAP kinase pathway, PI3 kinase/Akt pathway, and PLCγ. An association between the members of the FGF system and the improvement of neuropathic pain has become evident, recently. These signaling molecules may be expected to provide new drug targets for the treatment of neuropathic pain. To the best of our knowledge, it is the first study that reviews the relationship between some members of the FGF system and neuropathic pain.
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Affiliation(s)
- Fatemeh Forouzanfar
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamid R Sadeghnia
- Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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10
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Stojkovic M, Han D, Jeong M, Stojkovic P, Stankovic KM. Human induced pluripotent stem cells and CRISPR/Cas-mediated targeted genome editing: Platforms to tackle sensorineural hearing loss. STEM CELLS (DAYTON, OHIO) 2021; 39:673-696. [PMID: 33586253 DOI: 10.1002/stem.3353] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 12/13/2020] [Indexed: 11/09/2022]
Abstract
Hearing loss (HL) is a major global health problem of pandemic proportions. The most common type of HL is sensorineural hearing loss (SNHL) which typically occurs when cells within the inner ear are damaged. Human induced pluripotent stem cells (hiPSCs) can be generated from any individual including those who suffer from different types of HL. The development of new differentiation protocols to obtain cells of the inner ear including hair cells (HCs) and spiral ganglion neurons (SGNs) promises to expedite cell-based therapy and screening of potential pharmacologic and genetic therapies using human models. Considering age-related, acoustic, ototoxic, and genetic insults which are the most frequent causes of irreversible damage of HCs and SGNs, new methods of genome editing (GE), especially the CRISPR/Cas9 technology, could bring additional opportunities to understand the pathogenesis of human SNHL and identify novel therapies. However, important challenges associated with both hiPSCs and GE need to be overcome before scientific discoveries are correctly translated to effective and patient-safe applications. The purpose of the present review is (a) to summarize the findings from published reports utilizing hiPSCs for studies of SNHL, hence complementing recent reviews focused on animal studies, and (b) to outline promising future directions for deciphering SNHL using disruptive molecular and genomic technologies.
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Affiliation(s)
- Miodrag Stojkovic
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Dongjun Han
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Minjin Jeong
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Petra Stojkovic
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Konstantina M Stankovic
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA.,Program in Speech and Hearing Bioscience and Technology, Harvard University, Cambridge, Massachusetts, USA.,Harvard Program in Therapeutic Science, Harvard Medical School, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
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11
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Nocera G, Jacob C. Mechanisms of Schwann cell plasticity involved in peripheral nerve repair after injury. Cell Mol Life Sci 2020; 77:3977-3989. [PMID: 32277262 PMCID: PMC7532964 DOI: 10.1007/s00018-020-03516-9] [Citation(s) in RCA: 195] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 03/09/2020] [Accepted: 03/30/2020] [Indexed: 01/01/2023]
Abstract
The great plasticity of Schwann cells (SCs), the myelinating glia of the peripheral nervous system (PNS), is a critical feature in the context of peripheral nerve regeneration following traumatic injuries and peripheral neuropathies. After a nerve damage, SCs are rapidly activated by injury-induced signals and respond by entering the repair program. During the repair program, SCs undergo dynamic cell reprogramming and morphogenic changes aimed at promoting nerve regeneration and functional recovery. SCs convert into a repair phenotype, activate negative regulators of myelination and demyelinate the damaged nerve. Moreover, they express many genes typical of their immature state as well as numerous de-novo genes. These genes modulate and drive the regeneration process by promoting neuronal survival, damaged axon disintegration, myelin clearance, axonal regrowth and guidance to their former target, and by finally remyelinating the regenerated axon. Many signaling pathways, transcriptional regulators and epigenetic mechanisms regulate these events. In this review, we discuss the main steps of the repair program with a particular focus on the molecular mechanisms that regulate SC plasticity following peripheral nerve injury.
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Affiliation(s)
- Gianluigi Nocera
- Faculty of Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Mainz, Germany
| | - Claire Jacob
- Faculty of Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Mainz, Germany.
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12
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Chaney KE, Perrino MR, Kershner LJ, Patel AV, Wu J, Choi K, Rizvi TA, Dombi E, Szabo S, Largaespada DA, Ratner N. Cdkn2a Loss in a Model of Neurofibroma Demonstrates Stepwise Tumor Progression to Atypical Neurofibroma and MPNST. Cancer Res 2020; 80:4720-4730. [PMID: 32816910 DOI: 10.1158/0008-5472.can-19-1429] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 05/06/2020] [Accepted: 08/13/2020] [Indexed: 02/06/2023]
Abstract
Plexiform neurofibromas are benign nerve sheath Schwann cell tumors characterized by biallelic mutations in the neurofibromatosis type 1 (NF1) tumor suppressor gene. Atypical neurofibromas show additional frequent loss of CDKN2A/Ink4a/Arf and may be precursor lesions of aggressive malignant peripheral nerve sheath tumors (MPNST). Here we combined loss of Nf1 in developing Schwann cells with global Ink4a/Arf loss and identified paraspinal plexiform neurofibromas and atypical neurofibromas. Upon transplantation, atypical neurofibromas generated genetically engineered mice (GEM)-PNST similar to human MPNST, and tumors showed reduced p16INK4a protein and reduced senescence markers, confirming susceptibility to transformation. Superficial GEM-PNST contained regions of nerve-associated plexiform neurofibromas or atypical neurofibromas and grew rapidly on transplantation. Transcriptome analyses showed similarities to corresponding human tumors. Thus, we recapitulated nerve tumor progression in NF1 and provided preclinical platforms for testing therapies at each tumor grade. These results support a tumor progression model in which loss of NF1 in Schwann cells drives plexiform neurofibromas formation, additional loss of Ink4a/Arf contributes to atypical neurofibromas formation, and further changes underlie transformation to MPNST. SIGNIFICANCE: New mouse models recapitulate the stepwise progression of NF1 tumors and will be useful to define effective treatments that halt tumor growth and tumor progression in NF1.
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Affiliation(s)
- Katherine E Chaney
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio
| | - Melissa R Perrino
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio
| | - Leah J Kershner
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio
| | - Ami V Patel
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio
| | - Jianqiang Wu
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio
| | - Kwangmin Choi
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio
| | - Tilat A Rizvi
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio
| | - Eva Dombi
- Center for Cancer Research, National Cancer Institute, Bethesda, Maryland
| | - Sara Szabo
- Department of Pediatrics and Department of Pediatric Pathology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio
| | - David A Largaespada
- Departments of Pediatrics and Genetics, Cell Biology and Development, Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota
| | - Nancy Ratner
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio.
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13
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Gavini CK, Bonomo R, Mansuy-Aubert V. Neuronal LXR Regulates Neuregulin 1 Expression and Sciatic Nerve-Associated Cell Signaling in Western Diet-fed Rodents. Sci Rep 2020; 10:6396. [PMID: 32286429 PMCID: PMC7156713 DOI: 10.1038/s41598-020-63357-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/21/2020] [Indexed: 11/09/2022] Open
Abstract
Neuropathic pain caused by peripheral nerve injuries significantly affects sensory perception and quality of life. Accumulating evidence strongly link cholesterol with development and progression of Obesity and Diabetes associated-neuropathies. However, the exact mechanisms of how cholesterol/lipid metabolism in peripheral nervous system (PNS) contributes to the pathogenesis of neuropathy remains poorly understood. Dysregulation of LXR pathways have been identified in many neuropathic models. The cholesterol sensor, LXR α/β, expressed in sensory neurons are necessary for proper peripheral nerve function. Deletion of LXR α/β from sensory neurons lead to pain-like behaviors. In this study, we identified that LXR α/β expressed in sensory neurons regulates neuronal Neuregulin 1 (Nrg1), protein involved in cell-cell communication. Using in vivo cell-specific approaches, we observed that loss of LXR from sensory neurons altered genes in non-neuronal cells located in the sciatic nerve (potentially representing Schwann cells (SC)). Our data suggest that neuronal LXRs may regulate non-neuronal cell function via a Nrg1-dependent mechanism. The decrease in Nrg1 expression in DRG neurons of WD-fed mice may suggest an altered Nrg1-dependent neuron-SC communication in Obesity. The communication between neurons and non-neuronal cells such as SC could be a new biological pathway to study and understand the molecular and cellular mechanism underlying Obesity-associated neuropathy and PNS dysfunction.
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Affiliation(s)
- Chaitanya K Gavini
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, 60153, USA
| | - Raiza Bonomo
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, 60153, USA
| | - Virginie Mansuy-Aubert
- Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, 60153, USA.
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14
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Talagas M, Lebonvallet N, Leschiera R, Elies P, Marcorelles P, Misery L. Intra-epidermal nerve endings progress within keratinocyte cytoplasmic tunnels in normal human skin. Exp Dermatol 2020; 29:387-392. [PMID: 32003039 DOI: 10.1111/exd.14081] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 12/10/2019] [Accepted: 01/21/2020] [Indexed: 12/29/2022]
Abstract
Intra-epidermal nerve endings, responsible for cutaneous perception of temperature, pain and itch, are conventionally described as passing freely between keratinocytes, from the basal to the granular layers of the epidermis. However, the recent discovery of keratinocyte contribution to cutaneous nociception implies that their anatomical relationships are much more intimate than what has been described so far. By studying human skin biopsies in confocal laser scanning microscopy, we show that intra-epidermal nerve endings are not only closely apposed to keratinocytes, but can also be enwrapped by keratinocyte cytoplasms over their entire circumference and thus progress within keratinocyte tunnels. As keratinocytes must activate intra-epidermal nerve endings to transduce nociceptive information, these findings may help understanding the interactions between the keratinocytes and nervous system. The discovery of these nerve portions progressing in keratinocyte tunnels is a strong argument to consider that contacts between epidermal keratinocytes and intra-epidermal nerve endings are not incidental and argue for the existence of specific and rapid paracrine communication from keratinocytes to sensory neurons.
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Affiliation(s)
- Matthieu Talagas
- Univ Brest, LIEN, Brest, France
- Department of Pathology, Brest University Hospital, Brest, France
| | | | | | - Philippe Elies
- Univ Brest, Imagery and Microscopic Measures Facility, Brest, France
| | - Pascale Marcorelles
- Univ Brest, LIEN, Brest, France
- Department of Pathology, Brest University Hospital, Brest, France
| | - Laurent Misery
- Univ Brest, LIEN, Brest, France
- Department of Dermatology, Brest University Hospital, Brest, France
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15
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Mahan MA, Abou-Al-Shaar H, Karsy M, Warner W, Yeoh S, Palmer CA. Pathologic remodeling in human neuromas: insights from clinical specimens. Acta Neurochir (Wien) 2019; 161:2453-2466. [PMID: 31612277 DOI: 10.1007/s00701-019-04052-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 08/22/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Neuroma pathology is commonly described as lacking a clear internal structure, but we observed evidence that there are consistent architectural elements. Using human neuroma samples, we sought to identify molecular features that characterize neuroma pathophysiology. METHODS Thirty specimens-12 neuromas-in-continuity (NICs), 11 stump neuromas, two brachial plexus avulsions, and five controls-were immunohistochemically analyzed with antibodies against various components of normal nerve substructures. RESULTS There were no substantial histopathologic differences between stump neuromas and NICs, except that NICs had intact fascicle(s) in the specimen. These intact fascicles showed evidence of injury and fibrosis. On immunohistochemical analysis of the neuromas, laminin demonstrated a consistent double-lumen configuration. The outer lumen stained with GLUT1 antibodies, consistent with perineurium and microfascicle formation. Antibodies to NF200 revealed small clusters of small-diameter axons within the inner lumen, and the anti-S100 antibody showed a relatively regular pattern of non-myelinating Schwann cells. CD68+ cells were only seen in a limited temporal window after injury. T-cells were seen in neuroma specimens, with both a temporal evolution as well as persistence long after injury. Avulsion injury specimens had similar architecture to control nerves. Seven pediatric specimens were not qualitatively different from adult specimens. NICs demonstrated intact but abnormal fascicles that may account for the neurologically impoverished outcomes from untreated NICs. CONCLUSIONS We propose that there is consistent pathophysiologic remodeling after fascicle disruption. Particular features, such as predominance of small caliber axons and persistence of numerous T-cells long after injury, suggest a potential role in chronic pain associated with neuromas.
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Affiliation(s)
- Mark A Mahan
- Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA.
| | - Hussam Abou-Al-Shaar
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Michael Karsy
- Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA
| | - Wesley Warner
- Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA
| | - Stewart Yeoh
- Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA
| | - Cheryl A Palmer
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
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16
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Fledrich R, Kungl T, Nave KA, Stassart RM. Axo-glial interdependence in peripheral nerve development. Development 2019; 146:146/21/dev151704. [PMID: 31719044 DOI: 10.1242/dev.151704] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
During the development of the peripheral nervous system, axons and myelinating Schwann cells form a unique symbiotic unit, which is realized by a finely tuned network of molecular signals and reciprocal interactions. The importance of this complex interplay becomes evident after injury or in diseases in which aspects of axo-glial interaction are perturbed. This Review focuses on the specific interdependence of axons and Schwann cells in peripheral nerve development that enables axonal outgrowth, Schwann cell lineage progression, radial sorting and, finally, formation and maintenance of the myelin sheath.
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Affiliation(s)
- Robert Fledrich
- Institute of Anatomy, Leipzig University, 04103 Leipzig, Germany .,Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Theresa Kungl
- Institute of Anatomy, Leipzig University, 04103 Leipzig, Germany.,Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Ruth M Stassart
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany .,Department of Neuropathology, University Clinic Leipzig, 04103 Leipzig, Germany
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17
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Guo K, Elzinga S, Eid S, Figueroa-Romero C, Hinder LM, Pacut C, Feldman EL, Hur J. Genome-wide DNA methylation profiling of human diabetic peripheral neuropathy in subjects with type 2 diabetes mellitus. Epigenetics 2019; 14:766-779. [PMID: 31132961 PMCID: PMC6615525 DOI: 10.1080/15592294.2019.1615352] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
DNA methylation is an epigenetic mechanism important for the regulation of gene expression, which plays a vital role in the interaction between genetic and environmental factors. Aberrant epigenetic changes are implicated in the pathogenesis of diabetes and diabetic complications, but the role of DNA methylation in diabetic peripheral neuropathy (DPN) is not well understood. Therefore, our aim in this study was to explore the role of DNA methylation in the progression of DPN in type 2 diabetes. We compared genome-wide DNA methylation profiles of human sural nerve biopsies from subjects with stable or improving nerve fibre counts to biopsies from subjects with progressive loss of nerve fibres. Nerve fibre counts were determined by comparing myelinated nerve fibre densities between an initial and repeat biopsy separated by 52 weeks. Subjects with significant nerve regeneration (regenerators) and subjects with significant nerve degeneration (degenerators) represent the two extreme DPN phenotypes. Using reduced representation bisulfite sequencing, we identified 3,460 differentially methylated CpG dinucleotides between the two groups. The genes associated with differentially methylated CpGs were highly enriched in biological processes that have previously been implicated in DPN such as nervous system development, neuron development, and axon guidance, as well as glycerophospholipid metabolism and mitogen-activated protein kinase (MAPK) signalling. These findings are the first to provide a comprehensive analysis of DNA methylation profiling in human sural nerves of subjects with DPN and suggest that epigenetic regulation has an important role in the progression of this prevalent diabetic complication.
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Affiliation(s)
- Kai Guo
- a Department of Biomedical Sciences, School of Medicine and Health Sciences , University of North Dakota , Grand Forks , ND , USA
| | - Sarah Elzinga
- b Department of Neurology, School of Medicine , University of Michigan , Ann Arbor , MI , USA
| | - Stephanie Eid
- b Department of Neurology, School of Medicine , University of Michigan , Ann Arbor , MI , USA
| | - Claudia Figueroa-Romero
- b Department of Neurology, School of Medicine , University of Michigan , Ann Arbor , MI , USA
| | - Lucy M Hinder
- b Department of Neurology, School of Medicine , University of Michigan , Ann Arbor , MI , USA
| | - Crystal Pacut
- b Department of Neurology, School of Medicine , University of Michigan , Ann Arbor , MI , USA
| | - Eva L Feldman
- b Department of Neurology, School of Medicine , University of Michigan , Ann Arbor , MI , USA
| | - Junguk Hur
- a Department of Biomedical Sciences, School of Medicine and Health Sciences , University of North Dakota , Grand Forks , ND , USA
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18
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Chen C, Liu Q, Hua H, Wang X, Wang P, Cui Z, Qian T. Novel microRNA, miR-sc6, modulates Schwann cell phenotype via targeting ErbB4. Exp Ther Med 2019; 17:4116-4122. [PMID: 30988788 PMCID: PMC6447931 DOI: 10.3892/etm.2019.7426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 02/21/2019] [Indexed: 11/26/2022] Open
Abstract
MicroRNAs (miRNAs) are non-coding RNAs that regulate various tissues and organs, including the nervous system. Peripheral nerve injury is a common pathology of the nervous system and leads to differential expressions of a variety of miRNAs. Previously, a group of novel miRNAs have been identified in rat proximal nerve segments after sciatic nerve transection. However, the biological functions of these novel miRNAs remain undetermined. The aim of the current study was therefore to identify the function of a novel miRNA, miR-sc6, following nerve injury. Its target genes and effects on phenotypic modulation of Schwann cells were determined using a miR-sc6 mimic transfection. These observations contribute to the understanding of miRNA involvement in peripheral nerve injury and the cognition of regulatory mechanisms in peripheral nerve regeneration.
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Affiliation(s)
- Chu Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, P.R. China.,Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Qianyan Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Hao Hua
- Department of Medicine, Xinglin College, Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Xinghui Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Pan Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Zhiming Cui
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Tianmei Qian
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, P.R. China
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19
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Jiang N, Rasmussen JP, Clanton JA, Rosenberg MF, Luedke KP, Cronan MR, Parker ED, Kim HJ, Vaughan JC, Sagasti A, Parrish JZ. A conserved morphogenetic mechanism for epidermal ensheathment of nociceptive sensory neurites. eLife 2019; 8:42455. [PMID: 30855229 PMCID: PMC6450671 DOI: 10.7554/elife.42455] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 03/08/2019] [Indexed: 12/13/2022] Open
Abstract
Interactions between epithelial cells and neurons influence a range of sensory modalities including taste, touch, and smell. Vertebrate and invertebrate epidermal cells ensheath peripheral arbors of somatosensory neurons, including nociceptors, yet the developmental origins and functional roles of this ensheathment are largely unknown. Here, we describe an evolutionarily conserved morphogenetic mechanism for epidermal ensheathment of somatosensory neurites. We found that somatosensory neurons in Drosophila and zebrafish induce formation of epidermal sheaths, which wrap neurites of different types of neurons to different extents. Neurites induce formation of plasma membrane phosphatidylinositol 4,5-bisphosphate microdomains at nascent sheaths, followed by a filamentous actin network, and recruitment of junctional proteins that likely form autotypic junctions to seal sheaths. Finally, blocking epidermal sheath formation destabilized dendrite branches and reduced nociceptive sensitivity in Drosophila. Epidermal somatosensory neurite ensheathment is thus a deeply conserved cellular process that contributes to the morphogenesis and function of nociceptive sensory neurons. Humans and other animals perceive and interact with the outside world through their sensory nervous system. Nerve cells, acting as the body’s ‘telegraph wires’, convey signals from sensory organs – like the eyes – to the brain, which then processes this information and tells the body how to respond. There are different kinds of sensory nerve cells that carry different types of information, but they all associate closely with the tissues and organs they connect to the brain. Human skin contains sensory nerve cells, which underpin our senses of touch and pain. There is a highly specialized, complex connection between some of these nerve cells and cells in the skin: the skin cells wrap tightly around the nerve cells’ free ends, forming sheath-like structures. This ‘ensheathment’ process happens in a wide range of animals, including those with a backbone, like fish and humans, and those without, like insects. Ensheathment is thought to be important for the skin’s nerve cells to work properly. Yet it remains unclear how or when these connections first appear. Jiang et al. therefore wanted to determine the developmental origins of ensheathment and to find out if these were also similar in animals with and without backbones. Experiments using fruit fly and zebrafish embryos revealed that nerve cells, not skin cells, were responsible for forming and maintaining the sheaths. In embryos where groups of sensory nerve cells were selectively killed – either using a laser or by making the cells produce a toxin – ensheathment did not occur. Further studies, using a variety of microscopy techniques, revealed that the molecular machinery required to stabilize the sheaths was similar in both fish and flies, and therefore likely to be conserved across different groups of animals. Removing sheaths in fly embryos led to nerve cells becoming unstable; the animals were also less sensitive to touch. This confirmed that ensheathment was indeed necessary for sensory nerve cells to work properly. By revealing how ensheathment first emerges, these findings shed new light on how the sensory nervous system develops and how its activity is controlled. In humans, skin cells ensheath the nerve cells responsible for sensing pain. A better understanding of how ensheathments first arise could therefore lead to new avenues for treating chronic pain and related conditions.
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Affiliation(s)
- Nan Jiang
- Department of Biology, University of Washington, Seattle, United States
| | - Jeffrey P Rasmussen
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Joshua A Clanton
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Marci F Rosenberg
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Kory P Luedke
- Department of Biology, University of Washington, Seattle, United States
| | - Mark R Cronan
- Department of Molecular Genetics and Microbiology, Duke University, Durham, United States
| | - Edward D Parker
- Department of Opthalmology, University of Washington, Seattle, United States
| | - Hyeon-Jin Kim
- Department of Chemistry, University of Washington, Seattle, United States.,Department of Physiology and Biophysics, University of Washington, Seattle, United States
| | - Joshua C Vaughan
- Department of Chemistry, University of Washington, Seattle, United States.,Department of Physiology and Biophysics, University of Washington, Seattle, United States
| | - Alvaro Sagasti
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Jay Z Parrish
- Department of Biology, University of Washington, Seattle, United States
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20
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Fish Scales Dictate the Pattern of Adult Skin Innervation and Vascularization. Dev Cell 2018; 46:344-359.e4. [PMID: 30032992 DOI: 10.1016/j.devcel.2018.06.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 05/27/2018] [Accepted: 06/22/2018] [Indexed: 11/24/2022]
Abstract
As animals mature from embryonic to adult stages, the skin grows and acquires specialized appendages, like hairs, feathers, and scales. How cutaneous blood vessels and sensory axons adapt to these dramatic changes is poorly understood. By characterizing skin maturation in zebrafish, we discovered that sensory axons are delivered to the adult epidermis in organized nerves patterned by features in bony scales. These nerves associate with blood vessels and osteoblasts above scales. Osteoblasts create paths in scales that independently guide nerves and blood vessels during both development and regeneration. By preventing scale regeneration and examining mutants lacking scales, we found that scales recruit, organize, and polarize axons and blood vessels to evenly distribute them in the skin. These studies uncover mechanisms for achieving comprehensive innervation and vascularization of the adult skin and suggest that scales coordinate a metamorphosis-like transformation of the skin with sensory axon and vascular remodeling.
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21
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Sakai K, Shimba K, Kotani K, Jimbo Y. A co-culture microtunnel technique demonstrating a significant contribution of unmyelinated Schwann cells to the acceleration of axonal conduction in Schwann cell-regulated peripheral nerve development. Integr Biol (Camb) 2018; 9:678-686. [PMID: 28581556 DOI: 10.1039/c7ib00051k] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Schwann cells (SCs) contribute to the regulation of axonal conduction in a myelin-dependent and -independent manner. However, due to the lack of investigative techniques that are able to record axonal conduction under conditions that control the proliferation of specific SC types, little is known about the extent to which myelinated SCs (mSCs) and unmyelinated SCs (umSCs) modulate axonal conduction. In this study, a microtunnel-electrode approach was applied to a neuron/SC co-culture technique. Rat dorsal root ganglion neurons and SCs were co-cultured in a microtunnel-electrode device, which enabled recording of the conduction delay in multiple axons passing through microtunnels. Despite the absence of nuclei in the microtunnel when SCs were eliminated, cultured cells were densely packed and expressed S100 beta (an SC marker) at a rate of 96% in neuron/SC co-culture, indicating that SCs migrated into the microtunnel. In addition, supplementation with ascorbic acid after 6 days in vitro (DIV) successfully induced myelination from 22 DIV. Activity recording experiments indicated that the conduction delay decreased with culture length from 17 DIV in the neuron/SC co-culture but not in neuron monoculture. Interestingly, the SC-modulated shortening of conduction delay was attenuated at 17 DIV and 22 DIV by supplementing the culture medium with ascorbic acid and, at the same time, suppressing SC proliferation, suggesting that immature umSCs increased axonal conduction velocity in a cell density-dependent manner before the onset of myelination. These results suggest that this method is an effective tool for investigating the contributions of mSCs or umSCs to the regulation of axonal conduction.
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Affiliation(s)
- Koji Sakai
- School of Engineering, The University of Tokyo, Room 1122, Faculty of Engineering Building 14, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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22
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Zhao L, Li D, Liu N, Liu L, Zhang Z, Gao C, Kawano H, Zhou FY, Li HP. Correlation of TGN-020 with the analgesic effects via ERK pathway activation after chronic constriction injury. Mol Pain 2018; 14:1744806918796057. [PMID: 30152258 PMCID: PMC6113736 DOI: 10.1177/1744806918796057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/17/2018] [Accepted: 07/27/2018] [Indexed: 02/06/2023] Open
Abstract
Extracellular regulated protein kinase (ERK) pathway activation in astrocytes and neurons has been reported to be critical for neuropathic pain development after chronic constriction injury. TGN-020 was found to be the most potent aquaporin 4 inhibitor among the agents studied. The present study aimed to assess whether the inhibition of aquaporin 4 had an analgesic effect on neuropathic pain and whether the inhibition of astrocytic activation and ERK pathway was involved in the analgesic effect of TGN-020. We thus found that TGN-020 upregulated the threshold of thermal and mechanical allodynia, downregulated the expression of interleukin-1β, interleukin-6, and tumor necrosis factor-α, attenuated the astrocytic activation and suppressed the activation of mitogen-activated protein kinase pathways in the spinal dorsal horn and dorsal root ganglion. Additionally, TGN-020 suppressed ERK phosphorylation in astrocytes and neurons after injury. The findings suggested that the analgesic effects of TGN-020 in neuropathic pain were mediated mainly by the downregulation of chronic constriction injury-induced astrocytic activation and inflammation, which is via the inhibition of ERK pathway in the spinal dorsal horn and dorsal root ganglion.
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Affiliation(s)
- Liang Zhao
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
- Department of Orthopedic Surgery, Shenyang Fifth People’s
Hospital, Shenyang, China
| | - Dan Li
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Nan Liu
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Lu Liu
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Zhuo Zhang
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Chao Gao
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Hitoshi Kawano
- Department of Health and Dietetics, Faculty of Health and
Medical Science, Teikyo Heisei University, Tokyo, Japan
| | - Fang-Yuan Zhou
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Hong-Peng Li
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
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23
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Fazal SV, Gomez-Sanchez JA, Wagstaff LJ, Musner N, Otto G, Janz M, Mirsky R, Jessen KR. Graded Elevation of c-Jun in Schwann Cells In Vivo: Gene Dosage Determines Effects on Development, Remyelination, Tumorigenesis, and Hypomyelination. J Neurosci 2017; 37:12297-12313. [PMID: 29109239 PMCID: PMC5729195 DOI: 10.1523/jneurosci.0986-17.2017] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 09/22/2017] [Accepted: 10/08/2017] [Indexed: 11/21/2022] Open
Abstract
Schwann cell c-Jun is implicated in adaptive and maladaptive functions in peripheral nerves. In injured nerves, this transcription factor promotes the repair Schwann cell phenotype and regeneration and promotes Schwann-cell-mediated neurotrophic support in models of peripheral neuropathies. However, c-Jun is associated with tumor formation in some systems, potentially suppresses myelin genes, and has been implicated in demyelinating neuropathies. To clarify these issues and to determine how c-Jun levels determine its function, we have generated c-Jun OE/+ and c-Jun OE/OE mice with graded expression of c-Jun in Schwann cells and examined these lines during development, in adulthood, and after injury using RNA sequencing analysis, quantitative electron microscopic morphometry, Western blotting, and functional tests. Schwann cells are remarkably tolerant of elevated c-Jun because the nerves of c-Jun OE/+ mice, in which c-Jun is elevated ∼6-fold, are normal with the exception of modestly reduced myelin thickness. The stronger elevation of c-Jun in c-Jun OE/OE mice is, however, sufficient to induce significant hypomyelination pathology, implicating c-Jun as a potential player in demyelinating neuropathies. The tumor suppressor P19ARF is strongly activated in the nerves of these mice and, even in aged c-Jun OE/OE mice, there is no evidence of tumors. This is consistent with the fact that tumors do not form in injured nerves, although they contain proliferating Schwann cells with strikingly elevated c-Jun. Furthermore, in crushed nerves of c-Jun OE/+ mice, where c-Jun levels are overexpressed sufficiently to accelerate axonal regeneration, myelination and function are restored after injury.SIGNIFICANCE STATEMENT In injured and diseased nerves, the transcription factor c-Jun in Schwann cells is elevated and variously implicated in controlling beneficial or adverse functions, including trophic Schwann cell support for neurons, promotion of regeneration, tumorigenesis, and suppression of myelination. To analyze the functions of c-Jun, we have used transgenic mice with graded elevation of Schwann cell c-Jun. We show that high c-Jun elevation is a potential pathogenic mechanism because it inhibits myelination. Conversely, we did not find a link between c-Jun elevation and tumorigenesis. Modest c-Jun elevation, which is beneficial for regeneration, is well tolerated during Schwann cell development and in the adult and is compatible with restoration of myelination and nerve function after injury.
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Affiliation(s)
- Shaline V Fazal
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Jose A Gomez-Sanchez
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Laura J Wagstaff
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | | | - Georg Otto
- University College London Great Ormond Street Institute of Child Health, London WC1N1EH, United Kingdom, and
| | - Martin Janz
- Max Delbrück Center for Molecular Medicine and Charité, University Hospital Berlin, Campus Benjamin Franklin, 13092 Berlin, Germany
| | - Rhona Mirsky
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom,
| | - Kristján R Jessen
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom,
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Forouzanfar F, Amin B, Ghorbani A, Ghazavi H, Ghasemi F, Sadri K, Mehri S, Sadeghnia HR, Hosseinzadeh H. New approach for the treatment of neuropathic pain: Fibroblast growth factor 1 gene-transfected adipose-derived mesenchymal stem cells. Eur J Pain 2017; 22:295-310. [PMID: 28949091 DOI: 10.1002/ejp.1119] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2017] [Indexed: 12/13/2022]
Abstract
BACKGROUND Neuropathic pain triggered by peripheral nerve lesion is extremely difficult to manage with current approaches, hence the importance of exploring therapeutic alternatives. METHODS We have analysed adipose-derived mesenchymal stem cells (AD-MSCs) and fibroblast growth factor 1 gene-transfected adipose-derived mesenchymal stem cells (AD-MSCs FGF1 ) on chronic constriction injury (CCI). The mechanical and thermal hypersensitivity were assessed using the von Frey filament, radiant heat and acetone drop tests. Histopathological and apoptotic changes and the level of FGF1, GFAP and TNFα proteins were assessed in the lumbar portion (L4-L6). Moreover, AD-MSCs FGF1 were labelled with 99m Tc -HMPAO and isolated organ counting were performed upon AD-MSCs FGF1 administration. RESULTS Administration of AD-MSCs FGF1 attenuated the CCI-induced mechanical and thermal hypersensitivity. Spinal structural alterations and apoptosis were decreased in the AD-MSCs FGF1 group. The injection of either phosphate-buffered saline or normal NIH3T3 fibroblasts could not attenuate the behavioural symptoms of neuropathic pain. Increased genetically engineered cells were counted in the injured sciatic nerve and the elevated levels of FGF1 were detected in the spinal tissue. Stem cell therapy lead to decrement the level of the CCI-induced TNF-α and GFAP expression. CONCLUSION The intravenous administration of AD-MSCs FGF1 could be considered as a potential remedy for the management of neuropathic pain. SIGNIFICANCE AD-MSCs FGF1 attenuated the CCI-induced mechanical and thermal hypersensitivity. Spinal structural alterations and apoptosis were significantly decreased in the AD-MSCs FGF1 group. Elevated levels of FGF1 were detected in the spinal tissue.
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Affiliation(s)
- F Forouzanfar
- Department of Pharmacology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - B Amin
- Cellular and Molecular Research Center, Department of Physiology and Pharmacology, Faculty of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - A Ghorbani
- Pharmacological Research Center of Medicinal Plants, Mashhad University of Medical Sciences, Mashhad, Iran
| | - H Ghazavi
- Department of Medical Biotechnology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - F Ghasemi
- Department of Medical Biotechnology, Faculty of Medicine, Arak University of Medical Science, Arak, Iran
| | - K Sadri
- Nuclear Medicine Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - S Mehri
- Pharmaceutical Research Center, Pharmacodynamy and Toxicology Department, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - H R Sadeghnia
- Department of Pharmacology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - H Hosseinzadeh
- Pharmaceutical Research Center, Pharmacodynamy and Toxicology Department, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
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Vallières N, Barrette B, Wang LX, Bélanger E, Thiry L, Schneider MR, Filali M, Côté D, Bretzner F, Lacroix S. Betacellulin regulates schwann cell proliferation and myelin formation in the injured mouse peripheral nerve. Glia 2017; 65:657-669. [DOI: 10.1002/glia.23119] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 12/05/2016] [Accepted: 01/06/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Nicolas Vallières
- Centre de recherche du Centre hospitalier universitaire (CHU) de Québec-CHUL et Département de médecine moléculaire; Faculté de médecine, Université Laval; Québec Canada
| | - Benoit Barrette
- Centre de recherche du Centre hospitalier universitaire (CHU) de Québec-CHUL et Département de médecine moléculaire; Faculté de médecine, Université Laval; Québec Canada
| | - Linda Xiang Wang
- Centre de recherche du Centre hospitalier universitaire (CHU) de Québec-CHUL et Département de médecine moléculaire; Faculté de médecine, Université Laval; Québec Canada
| | - Erik Bélanger
- Centre de recherche de l'Institut universitaire en santé mentale de Québec (CRIUSMQ) et Département de physique, génie physique et optique, Faculté des sciences et de génie, Université Laval; Québec Canada
- Centre d'optique, photonique et laser (COPL), Université Laval; Québec Canada
| | - Louise Thiry
- Centre de recherche du CHU de Québec-CHUL et Département de psychiatrie et de neurosciences de l'Université Laval; Faculté de Médecine, Université Laval; Québec Canada
| | - Marlon R. Schneider
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich; Munich Germany
| | - Mohammed Filali
- Centre de recherche du Centre hospitalier universitaire (CHU) de Québec-CHUL et Département de médecine moléculaire; Faculté de médecine, Université Laval; Québec Canada
| | - Daniel Côté
- Centre de recherche de l'Institut universitaire en santé mentale de Québec (CRIUSMQ) et Département de physique, génie physique et optique, Faculté des sciences et de génie, Université Laval; Québec Canada
- Centre d'optique, photonique et laser (COPL), Université Laval; Québec Canada
| | - Frédéric Bretzner
- Centre de recherche du CHU de Québec-CHUL et Département de psychiatrie et de neurosciences de l'Université Laval; Faculté de Médecine, Université Laval; Québec Canada
| | - Steve Lacroix
- Centre de recherche du Centre hospitalier universitaire (CHU) de Québec-CHUL et Département de médecine moléculaire; Faculté de médecine, Université Laval; Québec Canada
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Wu J, Liu W, Williams JP, Ratner N. EGFR-Stat3 signalling in nerve glial cells modifies neurofibroma initiation. Oncogene 2016; 36:1669-1677. [PMID: 27748759 DOI: 10.1038/onc.2016.386] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 09/02/2016] [Accepted: 09/04/2016] [Indexed: 02/06/2023]
Abstract
Neurofibromatosis type 1 (NF1) is an inherited disease in which affected patients are predisposed to develop benign Schwann cell (SC) tumours called neurofibromas. In the mouse, loss of Nf1 in the SC lineage causes neurofibroma formation. The tyrosine kinase receptor EGFR is expressed in Schwann cell precursors (SCP), which have been implicated in plexiform neurofibroma initiation. To test if EGFR activity affects neurofibroma initiation, size, and/or number, we studied mice expressing human EGFR in SCs and SCP in the context of mice that form neurofibromas. Neurofibroma number increased in homozygous CNP-hEGFR mice versus heterozygous littermates, and neurofibroma number and size increased when CNP-hEGFR was crossed to Nf1fl/fl;DhhCre mice. Conversely, diminished EGFR signalling in Nf1fl/fl;DhhCre;Wa2/+ mice decreased neurofibroma number. In vivo transplantation verified the correlation between EGFR activity and neurofibroma formation. Mechanistically, expression of CNP-hEGFR increased SCP/neurofibroma-initiating cell self-renewal, a surrogate for tumour initiation, and activated P-Stat3. Further, Il-6 reinforced Jak2/Stat3 activation in SCPs and SCs. These gain- and loss-of function assays show that levels of tyrosine kinase expression in SCPs modify neurofibroma initiation.
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Affiliation(s)
- J Wu
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Research Foundation, Cincinnati Children's Hospital, University of Cincinnati, Cincinnati, OH, USA
| | - W Liu
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Research Foundation, Cincinnati Children's Hospital, University of Cincinnati, Cincinnati, OH, USA
| | - J P Williams
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Research Foundation, Cincinnati Children's Hospital, University of Cincinnati, Cincinnati, OH, USA
| | - N Ratner
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Research Foundation, Cincinnati Children's Hospital, University of Cincinnati, Cincinnati, OH, USA
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27
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Abstract
Diabetic neuropathy is a common secondary complication of diabetes that impacts on patient's health and well-being. Distal axon degeneration is a key feature of diabetic neuropathy, but the pathological changes which underlie axonal die-back are incompletely understood; despite decades of research a treatment has not yet been identified. Basic research must focus on understanding the complex mechanisms underlying changes that occur in the nervous system during diabetes. To this end, tissue culture techniques are invaluable as they enable researchers to examine the intricate mechanistic responses of cells to high glucose or other factors in order to better understand the pathogenesis of nerve dysfunction. This chapter describes the use of in vitro models to study a wide range of specific cellular effects pertaining to diabetic neuropathy including apoptosis, neurite outgrowth, neurodegeneration, activity, and bioenergetics. We consider problems associated with in vitro modeling and future refinement such as use of induced pluripotent stem cells and microfluidic technology.
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29
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Suarez-Mier GB, Buckwalter MS. Glial Fibrillary Acidic Protein-Expressing Glia in the Mouse Lung. ASN Neuro 2015; 7:7/5/1759091415601636. [PMID: 26442852 PMCID: PMC4601129 DOI: 10.1177/1759091415601636] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Autonomic nerves regulate important functions in visceral organs, including the lung. The postganglionic portion of these nerves is ensheathed by glial cells known as non-myelinating Schwann cells. In the brain, glia play important functional roles in neurotransmission, neuroinflammation, and maintenance of the blood brain barrier. Similarly, enteric glia are now known to have analogous roles in gastrointestinal neurotransmission, inflammatory response, and barrier formation. In contrast to this, very little is known about the function of glia in other visceral organs. Like the gut, the lung forms a barrier between airborne pathogens and the bloodstream, and autonomic lung innervation is known to affect pulmonary inflammation and lung function. Lung glia are described as non-myelinating Schwann cells but their function is not known, and indeed no transgenic tools have been validated to study them in vivo. The primary goal of this research was, therefore, to investigate the relationship between non-myelinating Schwann cells and pulmonary nerves in the airways and vasculature and to validate existing transgenic mouse tools that would be useful for studying their function. We focused on the glial fibrillary acidic protein promoter, which is a cognate marker of astrocytes that is expressed by enteric glia and non-myelinating Schwann cells. We describe the morphology of non-myelinating Schwann cells in the lung and verify that they express glial fibrillary acidic protein and S100, a classic glial marker. Furthermore, we characterize the relationship of non-myelinating Schwann cells to pulmonary nerves. Finally, we report tools for studying their function, including a commercially available transgenic mouse line.
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Affiliation(s)
- Gabriela B Suarez-Mier
- Department of Neurology and Neurological Sciences, Stanford Medical School, Stanford, CA, USA Stanford Neurosciences Institute, Stanford, CA, USA
| | - Marion S Buckwalter
- Department of Neurology and Neurological Sciences, Stanford Medical School, Stanford, CA, USA Department of Neurosurgery, Stanford Medical School, Stanford, CA, USA
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30
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Tang J, Qian Y, Li H, Kopecky BJ, Ding D, Ou HC, DeCook R, Chen X, Sun Z, Kobel M, Bao J. Canertinib induces ototoxicity in three preclinical models. Hear Res 2015; 328:59-66. [PMID: 26163095 DOI: 10.1016/j.heares.2015.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 06/23/2015] [Accepted: 07/03/2015] [Indexed: 12/16/2022]
Abstract
Neuregulin-1 (NRG1) ligand and its epidermal growth factor receptor (EGFR)/ERBB family regulate normal cellular proliferation and differentiation in many tissues including the cochlea. Aberrant NRG1 and ERBB signaling cause significant hearing impairment in mice. Dysregulation of the same signaling pathway in humans is involved in certain types of cancers such as breast cancer or non-small cell lung cancer (NSCLC). A new irreversible pan-ERBB inhibitor, canertinib, has been tested in clinical trials for the treatment of refractory NSCLC. Its possible ototoxicity was unknown. In this study, a significant dose-dependent canertinib ototoxicity was observed in a zebrafish model. Canertinib ototoxicity was further confirmed in two mouse models with different genetic backgrounds. The data strongly suggested an evolutionally preserved ERBB molecular mechanism underlying canertinib ototoxicity. Thus, these results imply that clinical monitoring of hearing loss should be considered for clinical testing of canertinib or other pan-ERBB inhibitors.
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Affiliation(s)
- Jian Tang
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Thoracic Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Yi Qian
- Department of Cardio-Thoracic Surgery, The Third Affiliated Hospital of Nantong University, Wuxi 214041, China
| | - Hui Li
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Benjamin J Kopecky
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Dalian Ding
- Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA
| | - Henry C Ou
- Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA; Department of Otolaryngology, University of Washington, Seattle, WA, USA
| | - Rhonda DeCook
- Department of Statistics and Actuarial Science, University of Iowa, Iowa City, IA 52242, USA
| | - Xiaojie Chen
- Gateway Biotechnology Inc., St. Louis, MO 63108, USA
| | - Zhenyu Sun
- Department of Cardio-Thoracic Surgery, The Third Affiliated Hospital of Nantong University, Wuxi 214041, China
| | - Megan Kobel
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Jianxin Bao
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH 44272, USA.
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Huang LL, Liu ZY, Huang JH, Luo ZJ. Expression pattern of neuregulin-1 type III during the development of the peripheral nervous system. Neural Regen Res 2015; 10:65-70. [PMID: 25788922 PMCID: PMC4357119 DOI: 10.4103/1673-5374.150708] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2014] [Indexed: 12/20/2022] Open
Abstract
Neuregulin-1 type III is a key regulator in Schwann cell proliferation, committing to a myelinating fate and regulating myelin sheath thickness. However, the expression pattern of neuregulin-1 type III in the peripheral nervous system during developmental periods (such as the premyelinating stage, myelinating stage and postmyelinating stage) has rarely been studied. In this study, dorsal root ganglia were isolated from rats between postnatal day 1 and postnatal day 56. The expression pattern of neuregulin-1 type III in dorsal root ganglia neurons at various developmental stages were compared by quantitative real-time polymerase chain reaction, western blot assay and immunofluorescent staining. The expression of neuregulin-1 type III mRNA reached its peak at postnatal day 3 and then stabilized at a relative high expression level from postnatal day 3 to postnatal day 56. The expression of neuregulin-1 type III protein increased gradually from postnatal day 1, reached a peak at postnatal day 28, and then decreased at postnatal day 56. Immunofluorescent staining results showed a similar tendency to western blot assay results. Experimental findings indicate that the expression of neuregulin-1 type III in rat dorsal root ganglion was increased during the premyelinating (from postnatal day 2 to postnatal day 5) and myelinating stage (from postnatal day 5 to postnatal day 10), but remained at a high level in the postmyelinating stage (after postnatal day 10).
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Affiliation(s)
- Liang-Liang Huang
- Department of Orthopedics, Xijing Hospital, the Fourth Military Medical University of Chinese PLA, Xi'an, Shaanxi Province, China
| | - Zhong-Yang Liu
- Department of Orthopedics, Xijing Hospital, the Fourth Military Medical University of Chinese PLA, Xi'an, Shaanxi Province, China
| | - Jing-Hui Huang
- Department of Orthopedics, Xijing Hospital, the Fourth Military Medical University of Chinese PLA, Xi'an, Shaanxi Province, China
| | - Zhuo-Jing Luo
- Department of Orthopedics, Xijing Hospital, the Fourth Military Medical University of Chinese PLA, Xi'an, Shaanxi Province, China
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32
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Namgung U. The role of Schwann cell-axon interaction in peripheral nerve regeneration. Cells Tissues Organs 2015; 200:6-12. [PMID: 25765065 DOI: 10.1159/000370324] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2014] [Indexed: 11/19/2022] Open
Abstract
After peripheral nerve injury, Schwann cells are released from the degenerating nerve, dedifferentiated, and then actively participate in axonal regeneration. Dedifferentiated Schwann cells, together with macrophages, are involved in eliminating myelin debris, forming bands of Büngner that provide pathways for regenerating axons, and redifferentiating for remyelination. Activation of Erk1/2 and c-Jun was shown to induce stepwise repair programs in Schwann cells, indicating that plastic changes in Schwann cell activity contribute to interaction with axons for regeneration. Schwann cell β1 integrin was identified to mediate the Cdc2-vimentin pathway and further connect to adaptor molecules in the growth cone of regenerating axons through the binding of extracellular matrix (ECM) proteins. Timely interaction between Schwann cells and the axon (S-A) is critical to achieving efficient axonal regeneration because the delay in S-A interaction results in retarded nerve repair and chronic nerve damage. By comparing with the role of Schwann cells in developing nerves, this review is focused on cellular and molecular aspects of Schwann cell interaction with axons at the early stages of regeneration.
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Affiliation(s)
- Uk Namgung
- Department of Oriental Medicine, Daejeon University, Daejeon, Republic of Korea
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33
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Grigoryan T, Birchmeier W. Molecular signaling mechanisms of axon-glia communication in the peripheral nervous system. Bioessays 2015; 37:502-13. [PMID: 25707700 DOI: 10.1002/bies.201400172] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this article we discuss the molecular signaling mechanisms that coordinate interactions between Schwann cells and the neurons of the peripheral nervous system. Such interactions take place perpetually during development and in adulthood, and are critical for the homeostasis of the peripheral nervous system (PNS). Neurons provide essential signals to control Schwann cell functions, whereas Schwann cells promote neuronal survival and allow efficient transduction of action potentials. Deregulation of neuron-Schwann cell interactions often results in developmental abnormalities and diseases. Recent investigations have shown that during development, neuronally provided signals, such as Neuregulin, Jagged, and Wnt interact to fine-tune the Schwann cell lineage progression. In adult, the signal exchange between neurons and Schwann cells ensures proper nerve function and regeneration. Identification of the mechanisms of neuron-Schwann cell interactions is therefore essential for our understanding of the development, function and pathology of the peripheral nervous system as a whole.
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Affiliation(s)
- Tamara Grigoryan
- Max-Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
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Affiliation(s)
- Iva D Tzvetanova
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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35
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Selective impact of Tau loss on nociceptive primary afferents and pain sensation. Exp Neurol 2014; 261:486-93. [DOI: 10.1016/j.expneurol.2014.07.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 07/08/2014] [Accepted: 07/20/2014] [Indexed: 01/06/2023]
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36
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Mei L, Nave KA. Neuregulin-ERBB signaling in the nervous system and neuropsychiatric diseases. Neuron 2014; 83:27-49. [PMID: 24991953 DOI: 10.1016/j.neuron.2014.06.007] [Citation(s) in RCA: 409] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Neuregulins (NRGs) comprise a large family of growth factors that stimulate ERBB receptor tyrosine kinases. NRGs and their receptors, ERBBs, have been identified as susceptibility genes for diseases such as schizophrenia (SZ) and bipolar disorder. Recent studies have revealed complex Nrg/Erbb signaling networks that regulate the assembly of neural circuitry, myelination, neurotransmission, and synaptic plasticity. Evidence indicates there is an optimal level of NRG/ERBB signaling in the brain and deviation from it impairs brain functions. NRGs/ERBBs and downstream signaling pathways may provide therapeutic targets for specific neuropsychiatric symptoms.
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Affiliation(s)
- Lin Mei
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA; Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA; Charlie Norwood VA Medical Center, Augusta, GA 30904, USA.
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Goettingen, Germany.
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Faroni A, Castelnovo LF, Procacci P, Caffino L, Fumagalli F, Melfi S, Gambarotta G, Bettler B, Wrabetz L, Magnaghi V. Deletion of GABA-B receptor in Schwann cells regulates remak bundles and small nociceptive C-fibers. Glia 2014; 62:548-65. [PMID: 24474699 DOI: 10.1002/glia.22625] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 12/16/2013] [Accepted: 12/19/2013] [Indexed: 12/16/2023]
Abstract
The mechanisms regulating the differentiation into non-myelinating Schwann cells is not completely understood. Recent evidence indicates that GABA-B receptors may regulate myelination and nociception in the peripheral nervous system. GABA-B receptor total knock-out mice exhibit morphological and molecular changes in peripheral myelin. The number of small myelinated fibers is higher and associated with altered pain sensitivity. Herein, we analyzed whether these changes may be produced by a specific deletion of GABA-B receptors in Schwann cells. The conditional mice (P0-GABA-B1(fl/fl)) show a morphological phenotype characterized by a peculiar increase in the number of small unmyelinated fibers and Remak bundles, including nociceptive C-fibers. The P0-GABA-B1(fl/fl) mice are hyperalgesic and allodynic. In these mice, the morphological and behavioral changes are associated with a downregulation of neuregulin 1 expression in nerves. Our findings suggest that the altered pain sensitivity derives from a Schwann cell-specific loss of GABA-B receptor functions, pointing to a role for GABA-B receptors in the regulation of Schwann cell maturation towards the non-myelinating phenotype.
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Affiliation(s)
- Alessandro Faroni
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Via Balzaretti 9, 20133, Milan, Italy; Blond McIndoe Laboratories, The University of Manchester, Institute of Inflammation and Repair, M13 9PT, Manchester, United Kingdom
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Koppes AN, Nordberg AL, Paolillo GM, Goodsell NM, Darwish HA, Zhang L, Thompson DM. Electrical stimulation of schwann cells promotes sustained increases in neurite outgrowth. Tissue Eng Part A 2014; 20:494-506. [PMID: 24063574 PMCID: PMC3926181 DOI: 10.1089/ten.tea.2013.0012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 09/03/2013] [Indexed: 12/20/2022] Open
Abstract
Endogenous electric fields are instructive during embryogenesis by acting to direct cell migration, and postnatally, they can promote axonal growth after injury (McCaig 1991, Al-Majed 2000). However, the mechanisms for these changes are not well understood. Application of an appropriate electrical stimulus may increase the rate and success of nerve repair by directly promoting axonal growth. Previously, DC electrical stimulation at 50 mV/mm (1 mA, 8 h duration) was shown to promote neurite outgrowth and a more pronounced effect was observed if both peripheral glia (Schwann cells) and neurons were co-stimulated. If electrical stimulation is delivered to an injury site, both the neurons and all resident non-neuronal cells [e.g., Schwann cells, endothelial cells, fibroblasts] will be treated and this biophysical stimuli can influence axonal growth directly or indirectly via changes to the resident, non-neuronal cells. In this work, non-neuronal cells were electrically stimulated, and changes in morphology and neuro-supportive cells were evaluated. Schwann cell response (morphology and orientation) was examined after an 8 h stimulation over a range of DC fields (0-200 mV/mm, DC 1 mA), and changes in orientation were observed. Electrically prestimulating Schwann cells (50 mV/mm) promoted 30% more neurite outgrowth relative to co-stimulating both Schwann cells with neurons, suggesting that electrical stimulation modifies Schwann cell phenotype. Conditioned medium from the electrically prestimulated Schwann cells promoted a 20% increase in total neurite outgrowth and was sustained for 72 h poststimulation. An 11-fold increase in nerve growth factor but not brain-derived neurotrophic factor or glial-derived growth factor was found in the electrically prestimulated Schwann cell-conditioned medium. No significant changes in fibroblast or endothelial morphology and neuro-supportive behavior were observed poststimulation. Electrical stimulation is widely used in clinical settings; however, the rational application of this cue may directly impact and enhance neuro-supportive behavior, improving nerve repair.
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Affiliation(s)
- Abigail N Koppes
- Department of Biomedical Engineering and Center for Biotechnology and Interdisciplinary Studies, Renssalaer Polytechnic Institute , Troy, New York
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Treating small fiber neuropathy by topical application of a small molecule modulator of ligand-induced GFRα/RET receptor signaling. Proc Natl Acad Sci U S A 2014; 111:2325-30. [PMID: 24449858 DOI: 10.1073/pnas.1308889111] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Small-fiber neuropathy (SFN) is a disorder of peripheral nerves commonly found in patients with diabetes mellitus, HIV infection, and those receiving chemotherapy. The complexity of disease etiology has led to a scarcity of effective treatments. Using two models of progressive SFN, we show that overexpression of glial cell line-derived neurotrophic factor (GDNF) in skin keratinocytes or topical application of XIB4035, a reported nonpeptidyl agonist of GDNF receptor α1 (GFRα1), are effective treatments for SFN. We also demonstrate that XIB4035 is not a GFRα1 agonist, but rather it enhances GFRα family receptor signaling in conjunction with ligand stimulation. Taken together, our results indicate that topical application of GFRα/RET receptor signaling modulators may be a unique therapy for SFN, and we have identified XIB4035 as a candidate therapeutic agent.
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Beirowski B. Concepts for regulation of axon integrity by enwrapping glia. Front Cell Neurosci 2013; 7:256. [PMID: 24391540 PMCID: PMC3867696 DOI: 10.3389/fncel.2013.00256] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 11/25/2013] [Indexed: 12/16/2022] Open
Abstract
Long axons and their enwrapping glia (EG; Schwann cells (SCs) and oligodendrocytes (OLGs)) form a unique compound structure that serves as conduit for transport of electric and chemical information in the nervous system. The peculiar cytoarchitecture over an enormous length as well as its substantial energetic requirements make this conduit particularly susceptible to detrimental alterations. Degeneration of long axons independent of neuronal cell bodies is observed comparatively early in a range of neurodegenerative conditions as a consequence of abnormalities in SCs and OLGs . This leads to the most relevant disease symptoms and highlights the critical role that these glia have for axon integrity, but the underlying mechanisms remain elusive. The quest to understand why and how axons degenerate is now a crucial frontier in disease-oriented research. This challenge is most likely to lead to significant progress if the inextricable link between axons and their flanking glia in pathological situations is recognized. In this review I compile recent advances in our understanding of the molecular programs governing axon degeneration, and mechanisms of EG’s non-cell autonomous impact on axon-integrity. A particular focus is placed on emerging evidence suggesting that EG nurture long axons by virtue of their intimate association, release of trophic substances, and neurometabolic coupling. The correction of defects in these functions has the potential to stabilize axons in a variety of neuronal diseases in the peripheral nervous system and central nervous system (PNS and CNS).
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Affiliation(s)
- Bogdan Beirowski
- Department of Genetics, Washington University School of Medicine Saint Louis, MO, USA
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Samara C, Poirot O, Domènech-Estévez E, Chrast R. Neuronal activity in the hub of extrasynaptic Schwann cell-axon interactions. Front Cell Neurosci 2013; 7:228. [PMID: 24324401 PMCID: PMC3839048 DOI: 10.3389/fncel.2013.00228] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/05/2013] [Indexed: 12/21/2022] Open
Abstract
The integrity and function of neurons depend on their continuous interactions with glial cells. In the peripheral nervous system glial functions are exerted by Schwann cells (SCs). SCs sense synaptic and extrasynaptic manifestations of action potential propagation and adapt their physiology to support neuronal activity. We review here existing literature data on extrasynaptic bidirectional axon-SC communication, focusing particularly on neuronal activity implications. To shed light on underlying mechanisms, we conduct a thorough analysis of microarray data from SC-rich mouse sciatic nerve at different developmental stages and in neuropathic models. We identify molecules that are potentially involved in SC detection of neuronal activity signals inducing subsequent glial responses. We further suggest that alterations in the activity-dependent axon-SC crosstalk impact on peripheral neuropathies. Together with previously reported data, these observations open new perspectives for deciphering glial mechanisms of neuronal function support.
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Affiliation(s)
- Chrysanthi Samara
- Department of Medical Genetics, University of Lausanne Lausanne, Switzerland
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Malmquist SJ, Abramsson A, McGraw HF, Linbo TH, Raible DW. Modulation of dorsal root ganglion development by ErbB signaling and the scaffold protein Sorbs3. Development 2013; 140:3986-96. [PMID: 24004948 DOI: 10.1242/dev.084640] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The multipotent cells of the vertebrate neural crest (NC) arise at the dorsal aspect of the neural tube, then migrate throughout the developing embryo and differentiate into diverse cell types, including the sensory neurons and glia of the dorsal root ganglia (DRG). As multiple cell types are derived from this lineage, it is ideal for examining mechanisms of fate restriction during development. We have isolated a mutant, ouchless, that specifically fails to develop DRG neurons, although other NC derivatives develop normally. This mutation affects the expression of Sorbs3, a scaffold protein known to interact with proteins involved in focal adhesions and several signaling pathways. ouchless mutants share some phenotypic similarities with mutants in ErbB receptors, EGFR homologs that are implicated in diverse developmental processes and associated with several cancers; and ouchless interacts genetically with an allele of erbb3 in DRG neurogenesis. However, the defect in ouchless DRG neurogenesis is distinct from ErbB loss of function in that it is not associated with a loss of glia. Both ouchless and neurogenin1 heterozygous fish are sensitized to the effects of ErbB chemical inhibitors, which block the development of DRG in a dose-dependent manner. Inhibitors of MEK show similar effects on DRG neurogenesis. We propose a model in which Sorbs3 helps to integrate ErbB signals to promote DRG neurogenesis through the activation of MAPK and upregulation of neurogenin1.
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Affiliation(s)
- Sarah J Malmquist
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
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Fricker FR, Antunes-Martins A, Galino J, Paramsothy R, La Russa F, Perkins J, Goldberg R, Brelstaff J, Zhu N, McMahon SB, Orengo C, Garratt AN, Birchmeier C, Bennett DLH. Axonal neuregulin 1 is a rate limiting but not essential factor for nerve remyelination. ACTA ACUST UNITED AC 2013; 136:2279-97. [PMID: 23801741 PMCID: PMC3692042 DOI: 10.1093/brain/awt148] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Neuregulin 1 acts as an axonal signal that regulates multiple aspects of Schwann cell
development including the survival and migration of Schwann cell precursors, the
ensheathment of axons and subsequent elaboration of the myelin sheath. To examine the role
of this factor in remyelination and repair following nerve injury, we ablated neuregulin 1
in the adult nervous system using a tamoxifen inducible Cre recombinase transgenic mouse
system. The loss of neuregulin 1 impaired remyelination after nerve crush, but did not
affect Schwann cell proliferation associated with Wallerian degeneration or axon
regeneration or the clearance of myelin debris by macrophages. Myelination changes were
most marked at 10 days after injury but still apparent at 2 months post-crush.
Transcriptional analysis demonstrated reduced expression of myelin-related genes during
nerve repair in animals lacking neuregulin 1. We also studied repair over a prolonged time
course in a more severe injury model, sciatic nerve transection and reanastamosis. In the
neuregulin 1 mutant mice, remyelination was again impaired 2 months after nerve
transection and reanastamosis. However, by 3 months post-injury axons lacking neuregulin 1
were effectively remyelinated and virtually indistinguishable from control. Neuregulin 1
signalling is therefore an important factor in nerve repair regulating the rate of
remyelination and functional recovery at early phases following injury. In contrast to
development, however, the determination of myelination fate following nerve injury is not
dependent on axonal neuregulin 1 expression. In the early phase following injury, axonal
neuregulin 1 therefore promotes nerve repair, but at late stages other signalling pathways
appear to compensate.
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Affiliation(s)
- Florence R Fricker
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU UK
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Pan P, Dobrowsky RT. Differential expression of neuregulin-1 isoforms and downregulation of erbin are associated with Erb B2 receptor activation in diabetic peripheral neuropathy. Acta Neuropathol Commun 2013; 1:39. [PMID: 24252174 PMCID: PMC3893607 DOI: 10.1186/2051-5960-1-39] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 07/15/2013] [Indexed: 11/17/2022] Open
Abstract
Background Aberrant neuron/glia interactions can contribute to a variety of neurodegenerative diseases and we have previously demonstrated that enhanced activation of Erb B2, which is a member of the epidermal growth factor receptor (EGFR) family, can contribute to the development of diabetic peripheral neuropathy (DPN). In peripheral nerves, Erb B receptors are activated by various members of the neuregulin-1 (NRG1) family including NRG1 Type I, NRG1 Type II and NRG1 Type III to regulate Schwann cell (SC) growth, migration, differentiation and dedifferentiation. Alternatively, Erb B2 activity can be negatively regulated by association with the Erb B2-interacting protein, erbin. Since the effect of diabetes on the expression of NRG1 isoforms and erbin in peripheral nerve are unknown, the current study determined whether changes in NRG1 isoforms and erbin may be associated with altered Erb B2 signaling in DPN. Results Swiss Webster mice were rendered diabetic with streptozotocin (STZ) and after 12 weeks of diabetes, treated with erlotinib, an inhibitor of Erb B2 activation. Inhibition of Erb B2 signaling partially reversed several pathophysiologic aspects of DPN including a pronounced sensory hypoalgesia, nerve conduction velocity deficits and the decrease in epidermal nerve fiber innervation. We also observed a decrease of NRG1 Type III but an increase of NRG1 Type I level in diabetic sural nerves at early stage of diabetes. With disease progression, we detected reduced erbin expression and enhanced MAPK pathway activity in diabetic mice. Inhibition of Erb B2 receptor suppressed MAPK pathway activity in treated-diabetic sural nerves. Conclusions These results support that hyperglycemia may impair NRG1/Erb B2 signaling by disrupting the balance between NRG1 isoforms, decreasing the expression of erbin and correspondingly activating the MAPK pathway. Together, imbalanced NRG1 isoforms and downregulated erbin may contribute to the dysregulation of Erb B2 signaling in the development of DPN.
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Schwann cell LRP1 regulates remak bundle ultrastructure and axonal interactions to prevent neuropathic pain. J Neurosci 2013; 33:5590-602. [PMID: 23536074 DOI: 10.1523/jneurosci.3342-12.2013] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Trophic support and myelination of axons by Schwann cells in the PNS are essential for normal nerve function. Herein, we show that deletion of the LDL receptor-related protein-1 (LRP1) gene in Schwann cells (scLRP1(-/-)) induces abnormalities in axon myelination and in ensheathment of axons by nonmyelinating Schwann cells in Remak bundles. These anatomical changes in the PNS were associated with mechanical allodynia, even in the absence of nerve injury. In response to crush injury, sciatic nerves in scLRP1(-/-) mice showed accelerated degeneration and Schwann cell death. Remyelinated axons were evident 20 d after crush injury in control mice, yet were largely absent in scLRP1(-/-) mice. In the partial nerve ligation model, scLRP1(-/-) mice demonstrated significantly increased and sustained mechanical allodynia and loss of motor function. Evidence for central sensitization in pain processing included increased p38MAPK activation and activation of microglia in the spinal cord. These studies identify LRP1 as an essential mediator of normal Schwann cell-axonal interactions and as a pivotal regulator of the Schwann cell response to PNS injury in vivo. Mice in which LRP1 is deficient in Schwann cells represent a model for studying how abnormalities in Schwann cell physiology may facilitate and sustain chronic pain.
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Xu P, Rosen KM, Hedstrom K, Rey O, Guha S, Hart C, Corfas G. Nerve injury induces glial cell line-derived neurotrophic factor (GDNF) expression in Schwann cells through purinergic signaling and the PKC-PKD pathway. Glia 2013; 61:1029-40. [PMID: 23553603 DOI: 10.1002/glia.22491] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 02/06/2013] [Indexed: 12/22/2022]
Abstract
Upon peripheral nerve injury, specific molecular events, including increases in the expression of selected neurotrophic factors, are initiated to prepare the tissue for regeneration. However, the mechanisms underlying these events and the nature of the cells involved are poorly understood. We used the injury-induced upregulation of glial cell-derived neurotrophic factor (GDNF) expression as a tool to gain insights into these processes. We found that both myelinating and nonmyelinating Schwann cells are responsible for the dramatic increase in GDNF expression after injury. We also demonstrate that the GDNF upregulation is mediated by a signaling cascade involving activation of Schwann cell purinergic receptors, followed by protein kinase C signaling which activates protein kinase D (PKD), which leads to increased GDNF transcription. Given the potent effects of GDNF on survival and repair of injured peripheral neurons, we propose that targeting these pathways may yield therapeutic tools to treat peripheral nerve injury and neuropathies.
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Affiliation(s)
- Pin Xu
- F.M. Kirby Neurobiology Center, Children's Hospital Boston, Boston, MA, USA
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The characterisation of Pax3 expressant cells in adult peripheral nerve. PLoS One 2013; 8:e59184. [PMID: 23527126 PMCID: PMC3602598 DOI: 10.1371/journal.pone.0059184] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 02/12/2013] [Indexed: 12/25/2022] Open
Abstract
Pax3 has numerous integral functions in embryonic tissue morphogenesis and knowledge of its complex function in cells of adult tissue continues to unfold. Across a variety of adult tissue lineages, the role of Pax3 is principally linked to maintenance of the tissue’s resident stem/progenitor cell population. In adult peripheral nerves, Pax3 is reported to be expressed in nonmyelinating Schwann cells, however, little is known about the purpose of this expression. Based on the evidence of the role of Pax3 in other adult tissue stem and progenitor cells, it was hypothesised that the cells in adult peripheral nerve that express Pax3 may be peripheral glioblasts. Here, methods have been developed for identification and visualisation of Pax3 expressant cells in normal 60 day old mouse peripheral nerve that allowed morphological and phenotypic distinctions to be made between Pax3 expressing cells and other nonmyelinating Schwann cells. The distinctions described provide compelling support for a resident glioblast population in adult mouse peripheral nerve.
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Mizobuchi S, Kanzaki H, Omiya H, Matsuoka Y, Obata N, Kaku R, Nakajima H, Ouchida M, Morita K. Spinal nerve injury causes upregulation of ErbB2 and ErbB3 receptors in rat dorsal root ganglia. J Pain Res 2013; 6:87-94. [PMID: 23403761 PMCID: PMC3569052 DOI: 10.2147/jpr.s40967] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
It is generally known that peripheral nerve injury causes changes in expression of some growth factors in the dorsal root ganglion. Altered expression of ErbB receptors, a well-known growth factor in somatic cells, reportedly follows peripheral nerve injury in the spinal dorsal horn; however, it remains unknown whether the expression of these receptors is altered in the dorsal root ganglion after nerve injury. Therefore, this study examined the gene expression profiles of ErbB receptors in bilateral lumbar (L)4/L5 dorsal root ganglia, using L5-selective spinal nerve ligation in model rats as a peripheral nerve injury model. The expression of ErbB2 and ErbB3 was observed in the dorsal root ganglia of the mature rat, despite ErbB1 and ErbB4 showing only subtle expression. We also demonstrated that peripheral nerve injury induced significant increases in ErbB2 and ErbB3 in the ipsilateral dorsal root ganglion as compared with uninjured nerve. Expression changes in ErbB receptors appear to play important roles in nerve injury and subsequent nerve regeneration.
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Affiliation(s)
- Satoshi Mizobuchi
- Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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West NX, Lussi A, Seong J, Hellwig E. Scaffold-free microtissues: differences from monolayer cultures and their potential in bone tissue engineering. Clin Oral Investig 2013; 17:9-17. [PMID: 22695872 PMCID: PMC3585766 DOI: 10.1007/s00784-012-0763-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Accepted: 05/23/2012] [Indexed: 12/16/2022]
Abstract
OBJECTIVES Cell-based therapies for bone augmentation after tooth loss and for the treatment of periodontal defects improve healing defects. Usually, osteogenic cells or stem cells are cultivated in 2D primary cultures, before they are combined with scaffold materials, even though this means a loss of the endogenous 3D microenvironment for the cells. Moreover, the use of single-cell suspensions for the inoculation of scaffolds or for the direct application into an area of interest has the disadvantages of low initial cell numbers and susceptibility to unwanted cellular distribution, respectively. MATERIALS AND METHODS We addressed the question whether an alternative to monolayer cultures, namely 3D microtissues, has the potential to improve osteogenic tissue engineering and its clinical outcome. RESULTS By contrast, to monolayer cultures, osteogenic differentiation of 3D microtissues is enhanced by mimicking in vivo conditions. It seems that the osteogenic differentiation in microtissues is enhanced by strong integrin-extracellular matrix interaction and by stronger autocrine BMP2 signaling. Moreover, microtissues are less prone to wash out by body fluids and allow the precise administration of large cell numbers. CONCLUSION Microtissue cultures have closer characteristics with cells in vivo and their enhanced osteogenic differentiation makes scaffold-free microtissues a promising concept in osteogenic tissue engineering. CLINICAL RELEVANCE Microtissues are particularly suitable for tissue engineering because they improve seeding efficiency of biomaterials by increasing the cell load of a scaffold. This results in accelerated osteogenic tissue formation and could contribute to earlier implant stability in mandibular bone augmentation.
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Affiliation(s)
- N. X. West
- />Clinical Trials Unit, Department of Oral and Dental Sciences, Bristol Dental Hospital, Lower Maudlin Street, Bristol, BS1 2LY UK
| | - A. Lussi
- />Department of Operative Dentistry, Preventive and Pediatric Dentistry, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - J. Seong
- />Clinical Trials Unit, Department of Oral and Dental Sciences, Bristol Dental Hospital, Lower Maudlin Street, Bristol, BS1 2LY UK
| | - E. Hellwig
- />Department of Operative Dentistry and Periodontology, Dental School and Hospital Dentistry, University Medical Center Freiburg, Freiburg im Breisgau, Germany
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Abstract
BACKGROUND Chronic constriction injury of the trigeminal infraorbital nerve results in transient analgesia followed by whisker pad mechanical allodynia in rats. Neuregulin 1 expressed on axonal membranes binds receptor tyrosine kinase ErbB, promoting Schwann cell development and remyelination. This study investigated whether orofacial mechanical allodynia is signaled by ErbB3-ErbB2 heterodimers in injured nerves. METHODS Whisker pad mechanical allodynia (von Frey stimuli) was quantified in wild type rats and in transgenic rats with Sleeping Beauty transposon mutation for neuregulin 1 transgene. Pain-related behavior was retested after intraperitoneal injection of the ErbB2 inhibitor Lapatinib, an agent shown by others to reduce breast cancer pain. Infraorbital nerve injury was evaluated histologically with myelin and neuronal biomarkers. ErbB3 changes over time were measured with western blots. RESULTS Whisker pad mechanical hypersensitivity began in week 2 in wild type rats (3.11 ± 5.93 g vs. 18.72 ± 0.00 g after sham surgery, n = 9, P < 0.001), indicating trigeminal neuropathic pain, but was not evident in transgenic rats (odds ratio: 1.12, 95% confidence interval: 0.38-3.35). Initiation of statistically significant mechanohypersensitivity was delayed until week 6 after surgery in transgenic rats (3.44 ± 4.60 g vs. 18.72 ± 0.00 g, n = 4, P < 0.001). Mechanical allodynia, which persisted 8 weeks in wild type rats was alleviated by Lapatinib (15 ± 3.89 g vs. 2.45 ± 1.13 g, n = 6, P < 0.001). Infraorbital nerve damage was verified histologically. Statistically significant ErbB3 increases (weeks 5 and 10) in wild type and transgenic rats (week 10) coincided with time points when mechanical hypersensitivity was present. CONCLUSION The Neuregulin 1-ErbB3-ErbB2 complex is a causal mechanism in nerve injury-induced trigeminal neuropathic pain. Understanding peripheral glial mechanisms after nerve injury will improve neuropathic pain treatment.
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