51
|
Mengke NS, Hu B, Han QP, Deng YY, Fang M, Xie D, Li A, Zeng HK. Rapamycin inhibits lipopolysaccharide-induced neuroinflammation in vitro and in vivo. Mol Med Rep 2016; 14:4957-4966. [PMID: 27779711 PMCID: PMC5355655 DOI: 10.3892/mmr.2016.5883] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 07/08/2016] [Indexed: 01/05/2023] Open
Abstract
Alzheimer's disease (AD) is the most common type of progressive neurodegenerative disorder, and is responsible for the most common form of dementia in the elderly. Inflammation occurs in the brains of patients with AD, and is critical for disease progression. In the present study, the effects of rapamycin (RAPA) on neuroinflammation lipopolysaccharide (LPS)-induced were investigated. SH-SY5Y human neuroblastoma cells were treated with 20 µg/ml LPS and 0.1, 1 or 10 nmol/l RAPA, and were analyzed at various time points (6, 12 and 24 h). The mRNA expression levels of interleukin (IL) 1β, IL6 and hypoxia-inducible factor 1α (HIF1α) were determined using reverse transcription-quantitative polymerase chain reaction. The protein expression levels of phosphorylated (p-)S6, p-nuclear factor κB (NFκB), p-inhibitor of NFκB kinase subunit β (IKKβ) and p-tau protein were measured by western blot analysis. p-IKKβ, p-NFκB, p-S6 and p-tau were significantly decreased at 6, 12 and 24 h when cells were treated with ≥0.1 nmol/ml RAPA. In addition, female Sprague Dawley rats were intracranially injected with a single dose of 100 µg/kg LPS in the absence or presence of 1 mg/kg RAPA pretreatment. Brain tissues were subjected to immunohistochemical analysis 6–24 h later, which revealed that the expression levels of HIF1α and p-S6 in rat cerebral cortex were increased following LPS injection; however, this increase was abrogated by RAPA treatment. RAPA may therefore be considered a potential therapeutic agent for the early or emergency treatment of neuroinflammation.
Collapse
Affiliation(s)
- Na-Shun Mengke
- Faculty of Graduate Studies, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Bei Hu
- Faculty of Graduate Studies, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Qian-Peng Han
- Faculty of Graduate Studies, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Yi-Yu Deng
- Department of Emergency and Critical Care Medicine, Guangdong General Hospital & Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Ming Fang
- Department of Emergency and Critical Care Medicine, Guangdong General Hospital & Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Di Xie
- Faculty of Graduate Studies, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Ang Li
- Department of Histoembryology, Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Hong-Ke Zeng
- Faculty of Graduate Studies, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| |
Collapse
|
52
|
Önger ME, Delibaş B, Türkmen AP, Erener E, Altunkaynak BZ, Kaplan S. The role of growth factors in nerve regeneration. Drug Discov Ther 2016; 10:285-291. [PMID: 27746416 DOI: 10.5582/ddt.2016.01058] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Nerve injuries result in functional loss in the innervated organ or body parts, and recovery is difficult unless surgical treatment has been done. Different surgical treatments have been suggested for nerve repair. Tissue engineering related to growth factors has arisen as an alternative approach for triggering and improving nerve regeneration. Therefore, the aim of this review is to provide a comprehensive analysis related to growth factors as tools for optimizing the regeneration process. Studies and reviews on the use of growth factors for nerve regeneration were compiled over the course of the review. According to literature review, it may be concluded that growth factors from different sources present promising treatment related to nerve regeneration involved in neuronal differentiation, greater myelination and axonal growth and proliferation of specific cells for nerve repair.
Collapse
Affiliation(s)
- Mehmet Emin Önger
- Department of Histology and Embryology, Faculty of Medicine, Ondokuz Mayis University
| | | | | | | | | | | |
Collapse
|
53
|
Rothaug M, Becker-Pauly C, Rose-John S. The role of interleukin-6 signaling in nervous tissue. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1218-27. [PMID: 27016501 DOI: 10.1016/j.bbamcr.2016.03.018] [Citation(s) in RCA: 300] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/18/2016] [Accepted: 03/21/2016] [Indexed: 12/21/2022]
Abstract
The cytokine interleukin-6 (IL-6) plays a critical role in the pathogenesis of inflammatory disorders and in the physiological homeostasis of neural tissue. Profound neuropathological changes, such as multiple sclerosis (MS), Parkinson's and Alzheimer's disease are associated with increased IL-6 expression in brain. Increased nocturnal concentrations of serum IL-6 are found in patients with impaired sleep whereas IL-6-deficient mice spend more time in rapid eye movement sleep associated with dreaming. IL-6 is crucial in the differentiation of oligodendrocytes, regeneration of peripheral nerves and acts as a neurotrophic factor. It exerts its cellular effects through two distinct pathways which include the anti-inflammatory pathway involving the membrane-bound IL-6 receptor (IL-6R) expressed on selective cells, including microglia, in a process known as classical signaling that is also critical for bacterial defense. In classical signaling binding of IL-6 to the membrane-bound IL-6R activates the β-receptor glycoprotein 130 (gp130) and subsequent down-stream signaling. The alternative, rather pro-inflammatory pathway, shown to mediate neurodegeneration in mice, termed trans-signaling, depends on a soluble form of the IL-6R that is capable of binding IL-6 to stimulate a response on distal cells that express gp130. A naturally occurring soluble form of gp130 (sgp130) has been identified that can specifically bind and neutralize the IL-6R/IL-6 complex. Thus, trans-signaling is blocked but classical signaling is completely unaffected. A modified, recombinant dimerized version of sgp130 (sgp130Fc) has successfully been used to block inflammatory processes in mice and may also be used in the clarification of IL-6 trans-signaling in neurological diseases.
Collapse
Affiliation(s)
- Michelle Rothaug
- Institute of Biochemistry, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany
| | - Christoph Becker-Pauly
- Institute of Biochemistry, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany
| | - Stefan Rose-John
- Institute of Biochemistry, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany.
| |
Collapse
|
54
|
Chen CH, Sung CS, Huang SY, Feng CW, Hung HC, Yang SN, Chen NF, Tai MH, Wen ZH, Chen WF. The role of the PI3K/Akt/mTOR pathway in glial scar formation following spinal cord injury. Exp Neurol 2016; 278:27-41. [PMID: 26828688 DOI: 10.1016/j.expneurol.2016.01.023] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 01/19/2016] [Accepted: 01/28/2016] [Indexed: 12/18/2022]
Abstract
Several studies suggest that glial scars pose as physical and chemical barriers that limit neurite regeneration after spinal cord injury (SCI). Evidences suggest that the activation of the PI3K/Akt/mTOR signaling pathway is involved in glial scar formation. Therefore, inhibition of the PI3K/Akt/mTOR pathway may beneficially attenuate glial scar formation after SCI. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) negatively regulates the PI3K/Akt/mTOR pathway. Therefore, we hypothesized that the overexpression of PTEN in the spinal cord will have beneficial effects after SCI. In the present study, we intrathecally injected a recombinant adenovirus carrying the pten gene (Ad-PTEN) to cause overexpression of PTEN in rats with contusion injured spinal cords. The results suggest overexpression of PTEN in spinal cord attenuated glial scar formation and led to improved locomotor function after SCI. Overexpression of PTEN following SCI attenuated gliosis, affected chondroitin sulfate proteoglycan expression, and improved axon regeneration into the lesion site. Furthermore, we suggest that the activation of the PI3K/Akt/mTOR pathway in astrocytes at 3 days after SCI may be involved in glial scar formation. Because delayed treatment with Ad-PTEN enhanced motor function recovery more significantly than immediate treatment with Ad-PTEN after SCI, the results suggest that the best strategy to attenuate glial scar formation could be to introduce 3 days after SCI. This study's findings thus have positive implications for patients who are unable to receive immediate medical attention after SCI.
Collapse
Affiliation(s)
- Chun-Hong Chen
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University and Academia Sinica, Kaohsiung, Taiwan
| | - Chun-Sung Sung
- Department of Anesthesiology, Taipei Veterans General Hospital, Taipei, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Shi-Ying Huang
- Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Chien-Wei Feng
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University and Academia Sinica, Kaohsiung, Taiwan
| | - Han-Chun Hung
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University and Academia Sinica, Kaohsiung, Taiwan
| | - San-Nan Yang
- I-Shou University, School of Medicine, College of Medicine and Department of Pediatrics, E-DA Hospital, Kaohsiung, Taiwan
| | - Nan-Fu Chen
- Division of Neurosurgery, Department of Surgery, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan
| | - Ming-Hong Tai
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University and Academia Sinica, Kaohsiung, Taiwan; Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan; Center for Neuroscience, National Sun Yat-sen University, Kaohsiung, Taiwan; Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Zhi-Hong Wen
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University and Academia Sinica, Kaohsiung, Taiwan; Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, Taiwan.
| | - Wu-Fu Chen
- Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, Taiwan; Department of Neurosurgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
| |
Collapse
|
55
|
Menezes GD, Goulart VG, Espírito-Santo S, Oliveira-Silva P, Serfaty CA, Campello-Costa P. Intravitreous Injection of Interleukin-6 Leads to a Sprouting in the Retinotectal Pathway at Different Stages of Development. Neuroimmunomodulation 2016; 23:81-7. [PMID: 27031648 DOI: 10.1159/000444529] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 02/05/2016] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE The development of retinotectal pathways form precise topographical maps is usually completed by the third postnatal week. Cytokines participate in the development and plasticity of the nervous system. We have previously shown that in vivo treatment with interleukin 2 disrupts the retinocollicular topographical order in early stages of development. Therefore, we decided to study the effect of a single intravitreous injection of IL-6 upon retinotectal circuitry in neonates and juvenile rats. MATERIALS AND METHODS Lister Hooded rats received an intravitreous injection of IL-6 (50 ng/ml) or vehicle (PBS) at either postnatal day (PND)10 or PND30 and the ipsilateral retinotectal pathway was evaluated 4 or 8 days later, respectively. RESULTS Our data showed that, at different stages of development, a single IL-6 intravitreous treatment did not produce an inflammatory response and increased retinal axon innervation throughout the visual layers of the superior colliculus. CONCLUSIONS Taken together, our data provide the first evidence that a single intravitreous injection with IL-6 leads to sprouting in the subcortical visual connections and suggest that small changes in IL-6 levels might be sufficient to impair the correct neuronal circuitry fine-tuning during brain development.
Collapse
Affiliation(s)
- Grasielle D Menezes
- Programa de Neurocix00EA;ncias, Departamento de Neurobiologia, Universidade Federal Fluminense, Niterx00F3;i, Brazil
| | | | | | | | | | | |
Collapse
|
56
|
DeFrancesco-Lisowitz A, Lindborg JA, Niemi JP, Zigmond RE. The neuroimmunology of degeneration and regeneration in the peripheral nervous system. Neuroscience 2015; 302:174-203. [PMID: 25242643 PMCID: PMC4366367 DOI: 10.1016/j.neuroscience.2014.09.027] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 09/08/2014] [Accepted: 09/10/2014] [Indexed: 12/25/2022]
Abstract
Peripheral nerves regenerate following injury due to the effective activation of the intrinsic growth capacity of the neurons and the formation of a permissive pathway for outgrowth due to Wallerian degeneration (WD). WD and subsequent regeneration are significantly influenced by various immune cells and the cytokines they secrete. Although macrophages have long been known to play a vital role in the degenerative process, recent work has pointed to their importance in influencing the regenerative capacity of peripheral neurons. In this review, we focus on the various immune cells, cytokines, and chemokines that make regeneration possible in the peripheral nervous system, with specific attention placed on the role macrophages play in this process.
Collapse
Affiliation(s)
| | - J A Lindborg
- Department of Neurosciences, Case Western Reserve University, Cleveland OH 44106-4975
| | - J P Niemi
- Department of Neurosciences, Case Western Reserve University, Cleveland OH 44106-4975
| | - R E Zigmond
- Department of Neurosciences, Case Western Reserve University, Cleveland OH 44106-4975
| |
Collapse
|
57
|
Radulovic M, Yoon H, Wu J, Mustafa K, Fehlings MG, Scarisbrick IA. Genetic targeting of protease activated receptor 2 reduces inflammatory astrogliosis and improves recovery of function after spinal cord injury. Neurobiol Dis 2015; 83:75-89. [PMID: 26316358 DOI: 10.1016/j.nbd.2015.08.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 08/01/2015] [Accepted: 08/19/2015] [Indexed: 11/25/2022] Open
Abstract
Inflammatory-astrogliosis exacerbates damage in the injured spinal cord and limits repair. Here we identify Protease Activated Receptor 2 (PAR2) as an essential regulator of these events with mice lacking the PAR2 gene showing greater improvements in motor coordination and strength after compression-spinal cord injury (SCI) compared to wild type littermates. Molecular profiling of the injury epicenter, and spinal segments above and below, demonstrated that mice lacking PAR2 had significantly attenuated elevations in key hallmarks of astrogliosis (glial fibrillary acidic protein (GFAP), vimentin and neurocan) and in expression of pro-inflammatory cytokines (interleukin-6 (IL-6), tumor necrosis factor (TNF) and interleukin-1 beta (IL-1β)). SCI in PAR2-/- mice was also accompanied by improved preservation of protein kinase C gamma (PKCγ)-immunopositive corticospinal axons and reductions in GFAP-immunoreactivity, expression of the pro-apoptotic marker BCL2-interacting mediator of cell death (BIM), and in signal transducer and activator of transcription 3 (STAT3). The potential mechanistic link between PAR2, STAT3 and astrogliosis was further investigated in primary astrocytes to reveal that the SCI-related serine protease, neurosin (kallikrein 6) promotes IL-6 secretion in a PAR2 and STAT3-dependent manner. Data point to a signaling circuit in primary astrocytes in which neurosin signaling at PAR2 promotes IL-6 secretion and canonical STAT3 signaling. IL-6 promotes expression of GFAP, vimentin, additional IL-6 and robust increases in both neurosin and PAR2, thereby driving the PAR2-signaling circuit forward. Given the significant reductions in astrogliosis and inflammation as well as superior neuromotor recovery observed in PAR2 knockout mice after SCI, we suggest that this receptor and its agonists represent new drug targets to foster neuromotor recovery.
Collapse
Affiliation(s)
- Maja Radulovic
- Neurobiology of Disease Program, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States
| | - Hyesook Yoon
- Department of Physical Medicine and Rehabilitation, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States; Department of Physiology and Biomedical Engineering, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States
| | - Jianmin Wu
- Department of Physical Medicine and Rehabilitation, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States
| | - Karim Mustafa
- Neurobiology of Disease Program, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States
| | - Michael G Fehlings
- Department of Surgery, Toronto Western Research Institute, Toronto, ON M5T 2S8, Canada
| | - Isobel A Scarisbrick
- Neurobiology of Disease Program, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States; Department of Physical Medicine and Rehabilitation, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States; Department of Physiology and Biomedical Engineering, Mayo Medical and Graduate School, Rehabilitation Medicine Research Center, Rochester, MN 55905, United States.
| |
Collapse
|
58
|
Carmel JB, Young W, Hart RP. Flipping the transcriptional switch from myelin inhibition to axon growth in the CNS. Front Mol Neurosci 2015; 8:34. [PMID: 26236189 PMCID: PMC4505142 DOI: 10.3389/fnmol.2015.00034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/06/2015] [Indexed: 01/01/2023] Open
Abstract
Poor regeneration of severed axons in the central nervous system (CNS) limits functional recovery. Regeneration failure involves interplay of inhibitory environmental elements and the growth state of the neuron. To find internal changes in gene expression that might overcome inhibitory environmental cues, we compared several paradigms that allow growth in the inhibitory environment. Conditions that allow axon growth by axotomized and cultured dorsal root ganglion (DRG) neurons on CNS myelin include immaturity (the first few postnatal days), high levels of cyclic adenosine mono phosphate (cAMP), and conditioning with a peripheral nerve lesion before explant. This shift from inhibition to growth depends on transcription. Seeking to understand the transcriptome changes that allow axon growth in the CNS, we collaborated with the Marie Filbin laboratory to identify several mRNAs that are functionally relevant, as determined by gain- and loss-of-function studies. In this Perspective, we review evidence from these experiments and discuss the merits of comparing multiple regenerative paradigms to identify a core transcriptional program for CNS axon regeneration.
Collapse
Affiliation(s)
- Jason B Carmel
- Brain Mind Research Institute and Departments of Pediatrics and Neurology, Weill Cornell Medical College New York, NY, USA ; Burke-Cornell Medical Research Institute White Plains, NY, USA
| | - Wise Young
- W.M. Keck Center for Collaborative Neuroscience and the Department of Cell Biology and Neuroscience, Rutgers University Piscataway, NJ, USA
| | - Ronald P Hart
- W.M. Keck Center for Collaborative Neuroscience and the Department of Cell Biology and Neuroscience, Rutgers University Piscataway, NJ, USA
| |
Collapse
|
59
|
Yang P, Qin Y, Bian C, Zhao Y, Zhang W. Intrathecal delivery of IL-6 reactivates the intrinsic growth capacity of pyramidal cells in the sensorimotor cortex after spinal cord injury. PLoS One 2015; 10:e0127772. [PMID: 25992975 PMCID: PMC4437647 DOI: 10.1371/journal.pone.0127772] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 04/20/2015] [Indexed: 01/23/2023] Open
Abstract
We have previously demonstrated the growth-promoting effect of intrathecal delivery of recombinant rat IL-6 immediately after corticospinal tract (CST) injury. Our present study aims to further clarify whether intrathecal delivery of IL-6 after CST injury could reactivate the intrinsic growth capacity of pyramidal cells in the sensorimotor cortex which project long axons to the spinal cord. We examined, by ELISA, levels of cyclic adenosine monophosphate (cAMP), adenylyl cyclase (AC, which synthesizes cAMP), phosphodiesterases (PDE, which degrades cAMP), and, by RT-PCR, the expression of regeneration-associated genes in the rat sensorimotor cortex after intrathecal delivery of IL-6 for 7 days, started immediately after CST injury. Furthermore, we injected retrograde neuronal tracer Fluorogold (FG) to the spinal cord to label pyramidal cells in the sensorimotor cortex, layers V and VI, combined with βIII-tubulin immunostaining, then we analyzed by immunohistochemisty and western blot the expression of the co-receptor gp-130 of IL-6 family, and pSTAT3 and mTOR, downstream IL-6/JAK/STAT3 and PI3K/AKT/mTOR signaling pathways respectively. We showed that intrathecal delivery of IL-6 elevated cAMP level and upregulated the expression of regeneration-associated genes including GAP-43, SPRR1A, CAP-23 and JUN-B, and the expression of pSTAT3 and mTOR in pyramidal cells of the sensorimotor cortex. In contrast, AG490, an inhibitor of JAK, partially blocked these effects of IL-6. All these results indicate that intrathecal delivery of IL-6 immediately after spinal cord injury can reactivate the intrinsic growth capacity of pyramidal cells in the sensorimotor cortex and these effects of IL-6 were partially JAK/STAT3-dependent.
Collapse
Affiliation(s)
- Ping Yang
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, 400038, P.R China
- * E-mail:
| | - Yu Qin
- Cadet Brigade, Third Military Medical University, Chongqing, 400038, P.R China
| | - Chen Bian
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, 400038, P.R China
| | - Yandong Zhao
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, 400038, P.R China
| | - Wen Zhang
- Cadet Brigade, Third Military Medical University, Chongqing, 400038, P.R China
| |
Collapse
|
60
|
Xiong XY, Yang QW. Rethinking the roles of inflammation in the intracerebral hemorrhage. Transl Stroke Res 2015; 6:339-41. [PMID: 25940771 DOI: 10.1007/s12975-015-0402-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 04/21/2015] [Indexed: 11/24/2022]
Affiliation(s)
- Xiao-Yi Xiong
- Department of Neurology, Xinqiao Hospital, the Third Military Medical University, No.183, Xinqiao Main Street, Shapingba District, Chongqing, 400037, China
| | | |
Collapse
|
61
|
Neves J, Demaria M, Campisi J, Jasper H. Of flies, mice, and men: evolutionarily conserved tissue damage responses and aging. Dev Cell 2015; 32:9-18. [PMID: 25584795 PMCID: PMC4450349 DOI: 10.1016/j.devcel.2014.11.028] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Studies in flies, mice, and human models have provided a conceptual framework for how paracrine interactions between damaged cells and the surrounding tissue control tissue repair. These studies have amassed evidence for an evolutionarily conserved secretory program that regulates tissue homeostasis. This program coordinates cell survival and proliferation during tissue regeneration and repair in young animals. By virtue of chronic engagement, however, it also contributes to the age-related decline of tissue homeostasis leading to degeneration, metabolic dysfunction, and cancer. Here, we review recent studies that shed light on the nature and regulation of this evolutionarily conserved secretory program.
Collapse
Affiliation(s)
- Joana Neves
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945, USA
| | - Marco Demaria
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945, USA
| | - Judith Campisi
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945, USA; Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94520, USA.
| | - Heinrich Jasper
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945, USA.
| |
Collapse
|
62
|
Ogai K, Kuwana A, Hisano S, Nagashima M, Koriyama Y, Sugitani K, Mawatari K, Nakashima H, Kato S. Upregulation of leukemia inhibitory factor (LIF) during the early stage of optic nerve regeneration in zebrafish. PLoS One 2014; 9:e106010. [PMID: 25162623 PMCID: PMC4146584 DOI: 10.1371/journal.pone.0106010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 07/25/2014] [Indexed: 12/12/2022] Open
Abstract
Fish retinal ganglion cells (RGCs) can regenerate their axons after optic nerve injury, whereas mammalian RGCs normally fail to do so. Interleukin 6 (IL-6)-type cytokines are involved in cell differentiation, proliferation, survival, and axon regrowth; thus, they may play a role in the regeneration of zebrafish RGCs after injury. In this study, we assessed the expression of IL-6-type cytokines and found that one of them, leukemia inhibitory factor (LIF), is upregulated in zebrafish RGCs at 3 days post-injury (dpi). We then demonstrated the activation of signal transducer and activator of transcription 3 (STAT3), a downstream target of LIF, at 3–5 dpi. To determine the function of LIF, we performed a LIF knockdown experiment using LIF-specific antisense morpholino oligonucleotides (LIF MOs). LIF MOs, which were introduced into zebrafish RGCs via a severed optic nerve, reduced the expression of LIF and abrogated the activation of STAT3 in RGCs after injury. These results suggest that upregulated LIF drives Janus kinase (Jak)/STAT3 signaling in zebrafish RGCs after nerve injury. In addition, the LIF knockdown impaired axon sprouting in retinal explant culture invitro; reduced the expression of a regeneration-associated molecule, growth-associated protein 43 (GAP-43); and delayed functional recovery after optic nerve injury invivo. In this study, we comprehensively demonstrate the beneficial role of LIF in optic nerve regeneration and functional recovery in adult zebrafish.
Collapse
Affiliation(s)
- Kazuhiro Ogai
- Department of Molecular Neurobiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
- Wellness Promotion Science Center, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Ayaka Kuwana
- Department of Clinical Laboratory Science, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Suguru Hisano
- Department of Clinical Laboratory Science, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Mikiko Nagashima
- Department of Molecular Neurobiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yoshiki Koriyama
- Department of Molecular Neurobiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
- Graduate School and Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Mie, Japan
| | - Kayo Sugitani
- Department of Clinical Laboratory Science, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Kazuhiro Mawatari
- Department of Clinical Laboratory Science, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Hiroshi Nakashima
- Department of Clinical Laboratory Science, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Satoru Kato
- Department of Molecular Neurobiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
- * E-mail:
| |
Collapse
|
63
|
Cui J, He W, Yi B, Zhao H, Lu K, Ruan H, Ma D. mTOR pathway is involved in ADP-evoked astrocyte activation and ATP release in the spinal dorsal horn in a rat neuropathic pain model. Neuroscience 2014; 275:395-403. [PMID: 24976516 DOI: 10.1016/j.neuroscience.2014.06.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/10/2014] [Accepted: 06/13/2014] [Indexed: 01/13/2023]
Abstract
BACKGROUND ATP/ADP-evoked spinal astrocyte activation plays a vital role in the development of neuropathic pain. We aim to investigate the role of mammalian target of rapamycin (mTOR) pathway on the spinal astrocyte activation in the neuropathic pain development in rats. METHODS Sprague Dawley (SD) rats were subjected to chronic constriction of the sciatic nerve (CCI). Rapamycin or ADP was intrathecally injected daily to explore their effects on spinal astrocyte activation and pain development. Expression of glial fibrillary acidic protein (GFAP) and mTOR in the spinal dorsal horn was assessed by immunohistochemistry. Von Frey hairs and Hargreaves paw withdrawal test were conducted to evaluate mechanical allodynia and thermal sensitivity, respectively. Firefly luciferase ATP assay was used to assess the change of ATP level in cerebrospinal fluid (CSF) and medium of cultured astrocytes. RESULTS GFAP expression was enhanced in the ipsilateral spinal dorsal horn from day 3 after surgery. GFAP and mTOR expression in the rat spinal dorsal horn on post-surgical day 14 was enhanced by daily intrathecal injection of ADP, which was inhibited by rapamycin. Rapamycin decreased lower mechanical pain threshold and the thermal withdrawal latency. Intrathecal injection of ADP enhanced the ATP release, which was partially inhibited by rapamycin. Study of cultured astrocytes indicated that ATP could be released from astrocytes. CONCLUSION Our data demonstrated that ADP enhanced neuropathic pain in CCI rats, which was inhibited by rapamycin. This study indicates that targeting mTOR pathway could serve as a novel therapeutic strategy in neuropathic pain management.
Collapse
Affiliation(s)
- J Cui
- Department of Anaesthesiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - W He
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - B Yi
- Department of Anaesthesiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - H Zhao
- Section of Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea & Westminster Hospital, London, UK
| | - K Lu
- Department of Anaesthesiology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
| | - H Ruan
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China.
| | - D Ma
- Section of Anaesthetics, Pain Medicine and Intensive Care, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea & Westminster Hospital, London, UK
| |
Collapse
|
64
|
Schizas N, Andersson B, Hilborn J, Hailer NP. Interleukin-1 receptor antagonist promotes survival of ventral horn neurons and suppresses microglial activation in mouse spinal cord slice cultures. J Neurosci Res 2014; 92:1457-65. [PMID: 24975034 DOI: 10.1002/jnr.23429] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 04/23/2014] [Accepted: 05/09/2014] [Indexed: 02/05/2023]
Abstract
Secondary damage after spinal cord injury (SCI) induces neuronal demise through neurotoxicity and inflammation, and interleukin (IL)-1β is a key inflammatory mediator. We hypothesized that IL-1β is released in spinal cord slice cultures (SCSC) and aimed at preventing the potentially neurotoxic effects of IL-1β by using interleukin-1 receptor antagonist (IL1RA). We hypothesized that IL1RA treatment enhances neuronal survival and suppresses microglial activation. SCSC were cultured up to 8 days in vitro (DIV) in the presence of IL1RA or without, either combined with trophic support using neurotrophin (NT)-3 or not. Four groups were studied: negative control, IL1RA, NT-3, and IL1RA + NT-3. IL-1β concentrations in supernatants were measured by ELISA. SCSC were immunohistochemically stained for NeuN and α-neurofilament, and microglial cells were visualized with isolectin B4 . After 8 DIV, ventral horn neurons were significantly more numerous in the IL1RA, NT-3, and IL1RA + NT-3 groups compared with negative controls. Activated microglial cells were significantly less numerous in the IL1RA, NT-3, and IL1RA + NT-3 groups compared with negative controls. Axons expanded into the collagen matrix after treatment with IL1RA, NT-3, or IL1RA + NT-3, but not in negative controls. IL-1β release from cultures peaked after 6 hr and was lowest in the IL1RA + NT-3 group. We conclude that IL-1β is released in traumatized spinal cord tissue and that IL1RA could exert its neuroprotective actions by blocking IL-1-receptors. IL1RA thereby sustains neuronal survival irrespective of the presence of additional trophic support. Microglial activation is suppressed in the presence of IL1RA, suggesting decreased inflammatory activity. IL1RA treatment approaches may have substantial impact following SCI.
Collapse
Affiliation(s)
- N Schizas
- The SpineLab, Institute of Surgical Sciences, Department of Orthopaedics, Uppsala University, SE-751 85, Uppsala, Sweden
| | | | | | | |
Collapse
|
65
|
Interleukin-6 inhibits voltage-gated sodium channel activity of cultured rat spinal cord neurons. Acta Neuropsychiatr 2014; 26:170-7. [PMID: 25142193 DOI: 10.1017/neu.2013.49] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Interleukin-6 (IL-6) is a pleiotropic proinflammatory cytokine that plays a key role in the injuries and diseases of the central nervous system (CNS). A voltage-gated Na+ channel (VGSC) is essential for the excitability and electrical properties of the neurons. However, there is still limited information on the role of IL-6 in voltage-gated sodium channels. Our study aimed to investigate the effects of IL-6 on Na+ currents in cultured spinal-cord neurons. METHODS VGSC currents were activated and recorded using whole-cell patch-clamp technique in the cultured rat spinal cord neurons. The effects of IL-6 concentration and exposure duration were examined. To determine whether any change in the number of channels in the plasma membrane can inhibit IL-6 on VGSC currents, we examined the expression of α1A (SCN1α) subunit mRNA level and protein level in the neurons before and after IL-6 induction using real-time polymerase chain reaction. RESULTS We verified that IL-6, through a receptor-mediated mechanism, suppressed Na+ currents in a time- and dose-dependent manner, but did not alter the voltage-dependent activation and inactivation. Gp130 was involved in this inhibition. Furthermore, the spike amplitude was also inhibited by IL-6 in the doses that decreased the Na+ currents. CONCLUSION VGSC currents are significantly inhibited by IL-6. Our findings reveal that the potential neuroprotection of IL-6 may result from the inhibitory effects on VGSC currents.
Collapse
|
66
|
Krumbholz M, Meinl E. B cells in MS and NMO: pathogenesis and therapy. Semin Immunopathol 2014; 36:339-50. [PMID: 24832354 DOI: 10.1007/s00281-014-0424-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/01/2014] [Indexed: 12/28/2022]
Abstract
B linage cells are versatile players in multiple sclerosis (MS) and neuromyelitis optica/neuromyelitis optica spectrum disorder (NMO). New potential targets of autoantibodies have been described recently. Pathogenic mechanisms extend further to antigen presentation and cytokine production, which are increasingly recognized as therapeutic targets. In addition to pro-inflammatory effects of B cells, they may act also as anti-inflammatory via production of interleukin (IL)-10, IL-35, and other mechanisms. Definition of regulatory B cell subsets is an ongoing issue. Recent studies have provided evidence for a loss of B cell self-tolerance in MS. An immunogenetic approach demonstrated exchange of B cell clones between CSF and blood. The central nervous system (CNS) of MS patients fosters B cell survival, at least partly via BAFF and APRIL. The unexpected increase of relapses in a trial with a soluble BAFF/APRIL receptor (atacicept) suggests that this system is involved in MS, but with features that are not yet understood. In this review, we further discuss evidence for B cell and Ig contribution to human MS and NMO pathogenesis, pro-inflammatory and regulatory B cell effector functions, impaired B cell immune tolerance, the B cell-fostering microenvironment in the CNS, and B cell-targeted therapeutic interventions for MS and NMO, including CD20 depletion (rituximab, ocrelizumab, and ofatumumab), anti-IL6-R (tocilizumab), complement-blocking (eculizumab), inhibitors of AQP4-Ig binding (aquaporumab, small molecular compounds), and BAFF/BAFF-R-targeting agents.
Collapse
Affiliation(s)
- Markus Krumbholz
- Institute of Clinical Neuroimmunology, Ludwig Maximilian University of Munich, Max-Lebsche-Platz 31, 81377, Munich, Germany,
| | | |
Collapse
|
67
|
Chucair-Elliott AJ, Conrady C, Zheng M, Kroll CM, Lane TE, Carr DJJ. Microglia-induced IL-6 protects against neuronal loss following HSV-1 infection of neural progenitor cells. Glia 2014; 62:1418-34. [PMID: 24807365 DOI: 10.1002/glia.22689] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 04/22/2014] [Accepted: 04/22/2014] [Indexed: 12/19/2022]
Abstract
Herpes virus type 1 (HSV-1) is one of the most widespread human pathogens and accounts for more than 90% of cases of herpes simplex encephalitis (HSE) causing severe and permanent neurologic sequelae among surviving patients. We hypothesize such CNS deficits are due to HSV-1 infection of neural progenitor cells (NPCs). In vivo, HSV-1 infection was found to diminish NPC numbers in the subventricular zone. Upon culture of NPCs in conditions that stimulate their differentiation, we found HSV-1 infection of NPCs resulted in the loss of neuronal precursors with no significant change in the percentage of astrocytes or oligodendrocytes. We propose this is due a direct effect of HSV-1 on neuronal survival without alteration of the differentiation process. The neuronal loss was prevented by the addition of microglia or conditioned media from NPC/microglia co-cultures. Using neutralizing antibodies and recombinant cytokines, we identified interleukin-6 (IL-6) as responsible for the protective effect by microglia, likely through its downstream Signal Transducer and Activator of Transcription 3 (STAT3) cascade.
Collapse
Affiliation(s)
- Ana J Chucair-Elliott
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | | | | | | | | | | |
Collapse
|
68
|
Sloan SA, Barres BA. Mechanisms of astrocyte development and their contributions to neurodevelopmental disorders. Curr Opin Neurobiol 2014; 27:75-81. [PMID: 24694749 DOI: 10.1016/j.conb.2014.03.005] [Citation(s) in RCA: 181] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 03/06/2014] [Accepted: 03/10/2014] [Indexed: 10/25/2022]
Abstract
The development of functional neural circuits relies upon the coordination of various cell types. In particular, astrocytes play a crucial role in orchestrating neural development by powerfully coordinating synapse formation and function, neuronal survival, and axon guidance. While astrocytes help to shape neural circuits in the developing brain, the mechanisms underlying their own development may play an equally crucial role in nervous system function. The onset of astrogenesis is a temporally regulated phenomenon that relies upon exogenously secreted cues and intrinsic chromatin changes. Defects in the mechanisms underlying astrogenesis or in astrocyte function during early development may contribute to the progression of a variety of neurodevelopmental disorders.
Collapse
Affiliation(s)
- Steven A Sloan
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305-5125, United States.
| | - Ben A Barres
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305-5125, United States
| |
Collapse
|
69
|
Codeluppi S, Fernandez-Zafra T, Sandor K, Kjell J, Liu Q, Abrams M, Olson L, Gray NS, Svensson CI, Uhlén P. Interleukin-6 secretion by astrocytes is dynamically regulated by PI3K-mTOR-calcium signaling. PLoS One 2014; 9:e92649. [PMID: 24667246 PMCID: PMC3965459 DOI: 10.1371/journal.pone.0092649] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 02/25/2014] [Indexed: 12/22/2022] Open
Abstract
After contusion spinal cord injury (SCI), astrocytes become reactive and form a glial scar. While this reduces spreading of the damage by containing the area of injury, it inhibits regeneration. One strategy to improve the recovery after SCI is therefore to reduce the inhibitory effect of the scar, once the acute phase of the injury has passed. The pleiotropic cytokine interleukin-6 (IL-6) is secreted immediately after injury and regulates scar formation; however, little is known about the role of IL-6 in the sub-acute phases of SCI. Interestingly, IL-6 also promotes axon regeneration, and therefore its induction in reactive astrocytes may improve regeneration after SCI. We found that IL-6 is expressed by astrocytes and neurons one week post-injury and then declines. Using primary cultures of rat astrocytes we delineated the molecular mechanisms that regulate IL-6 expression and secretion. IL-6 expression requires activation of p38 and depends on NF-κB transcriptional activity. Activation of these pathways in astrocytes occurs when the PI3K-mTOR-AKT pathway is inhibited. Furthermore, we found that an increase in cytosolic calcium concentration was necessary for IL-6 secretion. To induce IL-6 secretion in astrocytes, we used torin2 and rapamycin to block the PI3K-mTOR pathway and increase cytosolic calcium, respectively. Treating injured animals with torin2 and rapamycin for two weeks, starting two weeks after injury when the scar has been formed, lead to a modest effect on mechanical hypersensitivity, limited to the period of treatment. These data, taken together, suggest that treatment with torin2 and rapamycin induces IL-6 secretion by astrocytes and may contribute to the reduction of mechanical hypersensitivity after SCI.
Collapse
Affiliation(s)
- Simone Codeluppi
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
| | - Teresa Fernandez-Zafra
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Katalin Sandor
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Jacob Kjell
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Qingsong Liu
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mathew Abrams
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Lars Olson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Nathanael S. Gray
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Camilla I. Svensson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Per Uhlén
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
70
|
Hyon JY, Hose S, Gongora C, Sinha D, O'Brien T. Effect of macrophage migration inhibitory factor on corneal sensitivity after laser in situ keratomileusis in rabbit. KOREAN JOURNAL OF OPHTHALMOLOGY 2014; 28:170-6. [PMID: 24688261 PMCID: PMC3958634 DOI: 10.3341/kjo.2014.28.2.170] [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] [Received: 07/29/2013] [Accepted: 10/21/2013] [Indexed: 11/23/2022] Open
Abstract
Purpose To investigate the effect of macrophage migration inhibitory factor (MIF) on corneal sensitivity after laser in situ keratomileusis (LASIK) surgery. Methods New Zealand white rabbits were used in this study. A hinged corneal flap (160-µm thick) was created with a microkeratome, and -3.0 diopter excimer laser ablation was performed. Expressions of MIF mRNA in the corneal epithelial cells and surrounding inflammatory cells were analyzed using reverse transcription polymerase chain reaction at 48 hours after LASIK. After LASIK surgery, the rabbits were topically given either 1) a balanced salt solution (BSS), 2) MIF (100 ng/mL) alone, or 3) a combination of nerve growth factor (NGF, 100 ug/mL), neurotrophine-3 (NT-3, 100 ng/mL), interleukin-6 (IL-6, 5 ng/mL), and leukemia inhibitory factor (LIF, 5 ng/mL) four times a day for three days. Preoperative and postoperative corneal sensitivity at two weeks and at 10 weeks were assessed using the Cochet-Bonnet esthesiometer. Results Expression of MIF mRNA was 2.5-fold upregulated in the corneal epithelium and 1.5-fold upregulated in the surrounding inflammatory cells as compared with the control eyes. Preoperative baseline corneal sensitivity was 40.56 ± 2.36 mm. At two weeks after LASIK, corneal sensitivity was 9.17 ± 5.57 mm in the BSS treated group, 21.92 ± 2.44 mm in the MIF treated group, and 22.42 ± 1.59 mm in the neuronal growth factors-treated group (MIF vs. BSS, p < 0.0001; neuronal growth factors vs. BSS, p < 0.0001; MIF vs. neuronal growth factors, p = 0.815). At 10 weeks after LASIK, corneal sensitivity was 15.00 ± 9.65, 35.00 ± 5.48, and 29.58 ± 4.31 mm respectively (MIF vs. BSS, p = 0.0001; neuronal growth factors vs. BSS, p = 0.002; MIF vs. neuronal growth factors, p = 0.192). Treatment with MIF alone could achieve as much of an effect on recovery of corneal sensation as treatment with combination of NGF, NT-3, IL-6, and LIF. Conclusions Topically administered MIF plays a significant role in the early recovery of corneal sensitivity after LASIK in the experimental animal model.
Collapse
Affiliation(s)
- Joon Young Hyon
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Stacey Hose
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Debasish Sinha
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Terrence O'Brien
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Palm Beach Gardens, FL, USA
| |
Collapse
|
71
|
Tennant KA. Thinking outside the brain: structural plasticity in the spinal cord promotes recovery from cortical stroke. Exp Neurol 2014; 254:195-9. [PMID: 24518486 DOI: 10.1016/j.expneurol.2014.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 02/02/2014] [Indexed: 11/29/2022]
Abstract
Neuroanatomically connected regions distal to a cortical stroke can exhibit both degenerative and adaptive changes during recovery. As the locus for afferent somatosensory fibres and efferent motor fibres, the spinal cord is ideally situated to play a critical role in functional recovery. In contrast to the wealth of research into cortical plasticity after stroke, much less focus has previously been placed on the role of subcortical or spinal cord plasticity in recovery of function after cortical stroke. Little is known about the extent and spatiotemporal profile of spinal rewiring, its regulation by neurotrophins or inflammatory cytokines, or its potential as a therapeutic target to improve stroke recovery. This commentary examines the recent findings by Sist et al. (2014) that there is a distinct critical period of heightened structural plasticity, growth factor expression, and inflammatory cytokine production in the spinal cord. They suggest that neuroplasticity is highest during the first two weeks after stroke and tapers off dramatically by the fourth week. Spinal cord plasticity correlates with the severity of cortical injury and temporally matches periods of accelerated spontaneous recovery of skilled reaching function. The potential of treatments that extend or re-open this window of spinal cord plasticity, such as anti-Nogo-A antibodies or chondroitinase ABC, to dramatically improve recovery from cortical stroke in clinical populations is discussed.
Collapse
Affiliation(s)
- Kelly A Tennant
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada.
| |
Collapse
|
72
|
Hao N, Lü G, Liu X, Yu B, Wu H, Ji D, Li Y, Han X. Potential role of microRNA: identification and functional analysis of microRNA in corticospinal tract after unilateral lesions of the medullary pyramid. Neurosci Lett 2014; 564:37-42. [PMID: 24513234 DOI: 10.1016/j.neulet.2013.12.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 12/19/2013] [Accepted: 12/22/2013] [Indexed: 12/14/2022]
Abstract
Corticospinal tract is mainly descending tracts by dominating voluntary movement of the limbs and fine movement of distal limb, especially in mammals. Distal axonal degeneration is called anterograde degeneration. Proximal end is connected to the neuron cell body, whereas retrograde degeneration is very slight with the possibility of regeneration. MicroRNAs (miRNAs) are a short non-coding RNAs that regulate gene expression at the post-transcriptional level by binding with the 3' untranslated region of target mRNAs. In order to understand the mechanism of underlying gene alteration in the rostral and caudal, respectively, after the corticospinal tract injury, we analyzed rostral and caudal mRNA and miRNA, respectively, using microRNA and mRNA profiles. We combined the predicted targets of miRNA with differentially expressed mRNA for selecting intersection gene. To predict the function miRNAs, GO and KEGG enrichment analysis were performed to find genes associated with change of rostral and caudal, respectively. The bioinformatics analysis indicated that changes in miRNA and target mRNA expression affected rostral regeneration, including negative regulation of apoptosis, positive regulation of cell proliferation, cell adhesion, oligodendrocyte development etc. It also affected caudal degeneration, including induction of apoptosis, down-regulating nervous system development, immune response etc. The current results illustrated that corticospinal tract injury produces a wide range changes of miRNAs, whereas mRNA also showed significantly change which affects key biological processes after injury in rostral and caudal.
Collapse
Affiliation(s)
- Ning Hao
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Guangming Lü
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, China.
| | - Xiaodong Liu
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Bin Yu
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Huiqun Wu
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Dafeng Ji
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Yaofu Li
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Xiao Han
- Department of Anatomy and Neurobiology, the Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001, China
| |
Collapse
|
73
|
Sist B, Fouad K, Winship IR. Plasticity beyond peri-infarct cortex: spinal up regulation of structural plasticity, neurotrophins, and inflammatory cytokines during recovery from cortical stroke. Exp Neurol 2013; 252:47-56. [PMID: 24291254 DOI: 10.1016/j.expneurol.2013.11.019] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 10/24/2013] [Accepted: 11/20/2013] [Indexed: 12/12/2022]
Abstract
Stroke induces pathophysiological and adaptive processes in regions proximal and distal to the infarct. Recent studies suggest that plasticity at the level of the spinal cord may contribute to sensorimotor recovery after cortical stroke. Here, we compare the time course of heightened structural plasticity in the spinal cord against the temporal profile of cortical plasticity and spontaneous behavioral recovery. To examine the relation between trophic and inflammatory effectors and spinal structural plasticity, spinal expression of brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) was measured. Growth-associated protein 43 (GAP-43), measured at 3, 7, 14, or 28 days after photothrombotic stroke of the forelimb sensorimotor cortex (FL-SMC) to provide an index of periods of heightened structural plasticity, varied as a function of lesion size and time after stroke in the cortical hemispheres and the spinal cord. Notably, GAP-43 levels in the cervical spinal cord were significantly increased after FL-SMC lesion, but the temporal window of elevated structural plasticity was more finite in spinal cord relative to ipsilesional cortical expression (returning to baseline levels by 28 post-stroke). Peak GAP-43 expression in spinal cord occurred during periods of accelerated spontaneous recovery, as measured on the Montoya Staircase reaching task, and returned to baseline as recovery plateaued. Interestingly, spinal GAP-43 levels were significantly correlated with spinal levels of the inflammatory cytokines TNF-α and IL-6 as well as the neurotrophin NT-3, while a transient increase in BDNF levels preceded elevated GAP-43 expression. These data identify a significant but time-limited window of heightened structural plasticity in the spinal cord following stroke that correlates with spontaneous recovery and the spinal expression of inflammatory cytokines and neurotrophic factors.
Collapse
Affiliation(s)
- Bernice Sist
- Centre for Neuroscience, University of Alberta, Edmonton, Alberta T6G 2R3, Canada; Neurochemical Research Unit, University of Alberta, Edmonton, Alberta T6G 2R3, Canada.
| | - Karim Fouad
- Centre for Neuroscience, University of Alberta, Edmonton, Alberta T6G 2R3, Canada; Faculty of Rehabilitative Medicine, University of Alberta, Edmonton, Alberta T6G 2R3, Canada.
| | - Ian R Winship
- Centre for Neuroscience, University of Alberta, Edmonton, Alberta T6G 2R3, Canada; Department of Psychiatry, University of Alberta, Edmonton, Alberta T6G 2R3, Canada; Neurochemical Research Unit, University of Alberta, Edmonton, Alberta T6G 2R3, Canada.
| |
Collapse
|
74
|
Weishaupt N, Krajacic A, Fouad K. Lipopolysaccharide can induce errors in anatomical measures of neuronal plasticity by increasing tracing efficacy. Neurosci Lett 2013; 556:181-5. [PMID: 24157856 DOI: 10.1016/j.neulet.2013.10.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 10/09/2013] [Accepted: 10/11/2013] [Indexed: 01/10/2023]
Abstract
Evidence suggests that activating certain components of the immune system may increase regeneration and plasticity in the injured central nervous system. Investigating the effect of lipopolysaccharide (LPS), a potent endotoxin and immune activator, on neuronal plasticity in rat models of spinal cord injury, we discovered that systemic administration of LPS can increase the number of descending motor axons that transport neuronal tracers anterogradely to the spinal cord. This effect of LPS was not observed across all motor tracts traced in two different experiments, but was significant for two different tracers administered to corticospinal tract neurons. Densitometry measurement of traced corticospinal axons within the cervical gray matter revealed that normalization to the number of traced axons is crucial to avoid false-positive reports of increased plasticity following LPS injection. These findings indicate that assessments of neuronal growth based on neuronal tracing techniques should be normalized when inflammation or immune activation is an experimental variable.
Collapse
Affiliation(s)
- Nina Weishaupt
- Centre for Neuroscience, University of Alberta, 3-88 Corbett Hall, Edmonton, AB T6E 2G4, Canada.
| | | | | |
Collapse
|
75
|
Huang CJ, Mari DC, Whitehurst M, Slusher A, Wilson A, Shibata Y. Brain-derived neurotrophic factor expression ex vivo in obesity. Physiol Behav 2013; 123:76-9. [PMID: 24140987 DOI: 10.1016/j.physbeh.2013.10.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 10/03/2013] [Accepted: 10/09/2013] [Indexed: 12/01/2022]
Abstract
Obesity is associated with an increased risk in neurodegenerative diseases. To counteract the neuronal damage, the human body increases brain-derived neurotrophic factor (BDNF) expression, leading to neuronal survival and plasticity. Recently, peripheral blood mononuclear cells (PBMCs) have been found to release BDNF as a potential neuroprotective role of inflammation. Therefore, the purpose of this study was to examine whether lipopolysaccharide (LPS)-induced PBMC activation would lead to differences in BDNF and inflammatory responses between obese and non-obese subjects. Thirty-one subjects (14 obese and 17 non-obese), ages 18 to 30years, were recruited. PBMCs were cultured for 24h with 10ng/mL LPS. BDNF, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were measured in both plasma and cell culture supernatants. Our results did not illustrate any differences in plasma BDNF levels between obese and non-obese groups. However, obese subjects elicited a greater plasma IL-6 production, which was positively associated with plasma BDNF. Furthermore, LPS-induced PBMCs expressed significantly higher BDNF and IL-6 levels in obese subjects compared to the non-obese subjects. Finally, these BDNF levels were positively correlated with IL-6 response ex vivo. These findings suggest that under a high inflammatory state, PBMCs produce greater BDNF and IL-6 expression which may play a collaborative role to protect against neuronal damage associated with obesity.
Collapse
Affiliation(s)
- Chun-Jung Huang
- Department of Exercise Science and Health Promotion, Florida Atlantic University, Boca Raton, FL, United States.
| | | | | | | | | | | |
Collapse
|
76
|
Kyritsis N, Kizil C, Brand M. Neuroinflammation and central nervous system regeneration in vertebrates. Trends Cell Biol 2013; 24:128-35. [PMID: 24029244 DOI: 10.1016/j.tcb.2013.08.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 08/09/2013] [Accepted: 08/12/2013] [Indexed: 01/11/2023]
Abstract
Injuries in the central nervous system (CNS) are one of the leading causes of mortality or persistent disabilities in humans. One of the reasons why humans cannot recover from neuronal loss is the limited regenerative capacity of their CNS. By contrast, non-mammalian vertebrates exhibit widespread regeneration in diverse tissues including the CNS. Understanding those mechanisms activated during regeneration may improve the regenerative outcome in the severed mammalian CNS. Of those mechanisms, recent evidence suggests that inflammation may be important in regeneration. In this review we compare the different events following acute CNS injury in mammals and non-mammalian vertebrates. We also discuss the involvement of the immune response in initiating regenerative programs and how immune cells and neural stem/progenitor cells (NSPCs) communicate.
Collapse
Affiliation(s)
- Nikos Kyritsis
- DFG Center for Regenerative Therapies Dresden - Cluster of Excellence (CRTD), Technische Universität Dresden, Fetscherstraße 105, 01307, Dresden, Germany
| | - Caghan Kizil
- DFG Center for Regenerative Therapies Dresden - Cluster of Excellence (CRTD), Technische Universität Dresden, Fetscherstraße 105, 01307, Dresden, Germany
| | - Michael Brand
- DFG Center for Regenerative Therapies Dresden - Cluster of Excellence (CRTD), Technische Universität Dresden, Fetscherstraße 105, 01307, Dresden, Germany.
| |
Collapse
|
77
|
Cantinieaux D, Quertainmont R, Blacher S, Rossi L, Wanet T, Noël A, Brook G, Schoenen J, Franzen R. Conditioned medium from bone marrow-derived mesenchymal stem cells improves recovery after spinal cord injury in rats: an original strategy to avoid cell transplantation. PLoS One 2013; 8:e69515. [PMID: 24013448 PMCID: PMC3754952 DOI: 10.1371/journal.pone.0069515] [Citation(s) in RCA: 166] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/10/2013] [Indexed: 12/11/2022] Open
Abstract
Spinal cord injury triggers irreversible loss of motor and sensory functions. Numerous strategies aiming at repairing the injured spinal cord have been studied. Among them, the use of bone marrow-derived mesenchymal stem cells (BMSCs) is promising. Indeed, these cells possess interesting properties to modulate CNS environment and allow axon regeneration and functional recovery. Unfortunately, BMSC survival and differentiation within the host spinal cord remain poor, and these cells have been found to have various adverse effects when grafted in other pathological contexts. Moreover, paracrine-mediated actions have been proposed to explain the beneficial effects of BMSC transplantation after spinal cord injury. We thus decided to deliver BMSC-released factors to spinal cord injured rats and to study, in parallel, their properties in vitro. We show that, in vitro, BMSC-conditioned medium (BMSC-CM) protects neurons from apoptosis, activates macrophages and is pro-angiogenic. In vivo, BMSC-CM administered after spinal cord contusion improves motor recovery. Histological analysis confirms the pro-angiogenic action of BMSC-CM, as well as a tissue protection effect. Finally, the characterization of BMSC-CM by cytokine array and ELISA identified trophic factors as well as cytokines likely involved in the beneficial observed effects. In conclusion, our results support the paracrine-mediated mode of action of BMSCs and raise the possibility to develop a cell-free therapeutic approach.
Collapse
Affiliation(s)
- Dorothée Cantinieaux
- GIGA-Neuroscience, Axonal Regeneration and Cephalic Pain Unit, University of Liege, Liege, Belgium
| | - Renaud Quertainmont
- GIGA-Neuroscience, Axonal Regeneration and Cephalic Pain Unit, University of Liege, Liege, Belgium
| | - Silvia Blacher
- GIGA-Cancer, Laboratory of Biology of Tumour and Development, University of Liege, Liege, Belgium
| | - Loïc Rossi
- GIGA-Neuroscience, Axonal Regeneration and Cephalic Pain Unit, University of Liege, Liege, Belgium
| | - Thomas Wanet
- GIGA-Neuroscience, Axonal Regeneration and Cephalic Pain Unit, University of Liege, Liege, Belgium
| | - Agnès Noël
- GIGA-Cancer, Laboratory of Biology of Tumour and Development, University of Liege, Liege, Belgium
| | - Gary Brook
- Department of Neuropathology, University of Aachen, Aachen, Germany
| | - Jean Schoenen
- GIGA-Neuroscience, Axonal Regeneration and Cephalic Pain Unit, University of Liege, Liege, Belgium
| | - Rachelle Franzen
- GIGA-Neuroscience, Axonal Regeneration and Cephalic Pain Unit, University of Liege, Liege, Belgium
| |
Collapse
|
78
|
Brázda V, Klusáková I, Hradilová Svíženská I, Dubový P. Dynamic response to peripheral nerve injury detected by in situ hybridization of IL-6 and its receptor mRNAs in the dorsal root ganglia is not strictly correlated with signs of neuropathic pain. Mol Pain 2013; 9:42. [PMID: 23953943 PMCID: PMC3844395 DOI: 10.1186/1744-8069-9-42] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 08/14/2013] [Indexed: 12/15/2022] Open
Abstract
Background IL-6 is a typical injury-induced mediator. Together with its receptors, IL-6 contributes to both induction and maintenance of neuropathic pain deriving from changes in activity of primary sensory neurons in dorsal root ganglia (DRG). We used in situ hybridization to provide evidence of IL-6 and IL-6 receptors (IL-6R and gp130) synthesis in DRG along the neuraxis after unilateral chronic constriction injury (CCI) of the sciatic nerve as an experimental model of neuropathic pain. Results All rats operated upon to create unilateral CCI displayed mechanical allodynia and thermal hyperalgesia in ipsilateral hind paws. Contralateral hind paws and forepaws of both sides exhibited only temporal and nonsignificant changes of sensitivity. Very low levels of IL-6 and IL-6R mRNAs were detected in naïve DRG. IL-6 mRNA was bilaterally increased not only in DRG neurons but also in satellite glial cells (SGC) activated by unilateral CCI. In addition to IL-6 mRNA, substantial increase of IL-6R mRNA expression occurred in DRG neurons and SGC following CCI, while the level of gp130 mRNA remained similar to that of DRG from naïve rats. Conclusions Here we evidence for the first time increased synthesis of IL-6 and IL-6R in remote cervical DRG nonassociated with the nerve injury. Our results suggest that unilateral CCI of the sciatic nerve induced not only bilateral elevation of IL-6 and IL-6R mRNAs in L4–L5 DRG but also their propagation along the neuraxis to remote cervical DRG as a general neuroinflammatory reaction of the nervous system to local nerve injury without correlation with signs of neuropathic pain. Possible functional involvement of IL-6 signaling is discussed.
Collapse
Affiliation(s)
- Václav Brázda
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 3, 62500, Brno, Czech Republic.
| | | | | | | |
Collapse
|
79
|
Blockade of interleukin-6 receptor suppresses inflammatory reaction and facilitates functional recovery following olfactory system injury. Neurosci Res 2013; 76:125-32. [DOI: 10.1016/j.neures.2013.03.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 03/14/2013] [Accepted: 03/26/2013] [Indexed: 11/20/2022]
|
80
|
Dubový P, Brázda V, Klusáková I, Hradilová-Svíženská I. Bilateral elevation of interleukin-6 protein and mRNA in both lumbar and cervical dorsal root ganglia following unilateral chronic compression injury of the sciatic nerve. J Neuroinflammation 2013; 10:55. [PMID: 23634725 PMCID: PMC3657546 DOI: 10.1186/1742-2094-10-55] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 04/03/2013] [Indexed: 11/10/2022] Open
Abstract
Background Current research implicates interleukin (IL)-6 as a key component of the nervous-system response to injury with various effects. Methods We used unilateral chronic constriction injury (CCI) of rat sciatic nerve as a model for neuropathic pain. Immunofluorescence, ELISA, western blotting and in situ hybridization were used to investigate bilateral changes in IL-6 protein and mRNA in both lumbar (L4-L5) and cervical (C7-C8) dorsal root ganglia (DRG) following CCI. The operated (CCI) and sham-operated (sham) rats were assessed after 1, 3, 7, and 14 days. Withdrawal thresholds for mechanical hyperalgesia and latencies for thermal hyperalgesia were measured in both ipsilateral and contralateral hind and fore paws. Results The ipsilateral hind paws of all CCI rats displayed a decreased threshold of mechanical hyperalgesia and withdrawal latency of thermal hyperalgesia, while the contralateral hind and fore paws of both sides exhibited no significant changes in mechanical or thermal sensitivity. No significant behavioral changes were found in the hind and fore paws on either side of the sham rats, except for thermal hypersensitivity, which was present bilaterally at 3 days. Unilateral CCI of the sciatic nerve induced a bilateral increase in IL-6 immunostaining in the neuronal bodies and satellite glial cells (SGC) surrounding neurons of both lumbar and cervical DRG, compared with those of naive control rats. This bilateral increase in IL-6 protein levels was confirmed by ELISA and western blotting. More intense staining for IL-6 mRNA was detected in lumbar and cervical DRG from both sides of rats following CCI. The DRG removed from sham rats displayed a similar pattern of staining for IL-6 protein and mRNA as found in naive DRG, but there was a higher staining intensity in SGC. Conclusions Bilateral elevation of IL-6 protein and mRNA is not limited to DRG homonymous to the injured nerve, but also extended to DRG that are heteronymous to the injured nerve. The results for IL-6 suggest that the neuroinflammatory reaction of DRG to nerve injury is propagated alongside the neuroaxis from the lumbar to the remote cervical segments. This is probably related to conditioning of cervical DRG neurons to injury.
Collapse
Affiliation(s)
- Petr Dubový
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 3, Brno, 62500, Czech Republic.
| | | | | | | |
Collapse
|
81
|
Leibinger M, Müller A, Gobrecht P, Diekmann H, Andreadaki A, Fischer D. Interleukin-6 contributes to CNS axon regeneration upon inflammatory stimulation. Cell Death Dis 2013; 4:e609. [PMID: 23618907 PMCID: PMC3641349 DOI: 10.1038/cddis.2013.126] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mature retinal ganglion cells (RGCs) do not normally regenerate injured axons and undergo apoptosis after axotomy. Inflammatory stimulation (IS) in the eye mediates neuroprotection and induces axon regeneration into the injured optic nerve. Ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF) have been identified as key mediators of these effects. Here, we investigated the role of interleukin-6 (IL-6), another member of the glycoprotein 130-activating cytokine family, as additonal contributing factor. Expression of IL-6 was markedly induced in the retina upon optic nerve injury and IS, and mature RGCs expressed the IL-6 receptor. Treatment of cultured RGCs with IL-6 or specific IL-6 receptor agonist, significantly increased neurite outgrowth janus kinase/signal transducers and activators of transcription-3 (JAK/STAT3) and phosphatidylinositide 3-kinase/protein kinase B (PI3K/Akt) dependently. Moreover, IL-6 reduced myelin, but not neurocan-mediated growth inhibition mammalian target of rapamycin (mTOR) dependently in cultured RGCs. In vivo, intravitreal application of IL-6 transformed RGCs into a regenerative state, enabling axon regeneration beyond the lesion site of the optic nerve. On the other hand, genetic ablation of IL-6 in mice significantly reduced IS-mediated myelin disinhibition and axon regeneration in the optic nerve. Therefore, IL-6 contributes to the beneficial effects of IS and its disinhibitory effect adds an important feature to the effects of so far identified IS-mediating factors. Consequently, application of IL-6 or activation of its receptor might provide suitable strategies for enhancing optic nerve regeneration.
Collapse
Affiliation(s)
- M Leibinger
- Department of Neurology, Heinrich-Heine-University of Düsseldorf, Merowingerplatz 1a, Düsseldorf, Germany
| | | | | | | | | | | |
Collapse
|
82
|
Wu D, Murashov AK. Molecular mechanisms of peripheral nerve regeneration: emerging roles of microRNAs. Front Physiol 2013; 4:55. [PMID: 23554595 PMCID: PMC3612692 DOI: 10.3389/fphys.2013.00055] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 03/07/2013] [Indexed: 01/07/2023] Open
Abstract
MicroRNAs are small non-coding RNAs that suppress gene expression through target mRNA degradation or translation repression. Recent studies suggest that miRNA plays an important role in multiple physiological and pathological processes in the nervous system. In this review article, we described what is currently known about the mechanisms in peripheral nerve regeneration on cellular and molecular levels. Recently, changes in microRNA expression profiles have been detected in different injury models, and emerging evidence strongly indicates that these changes promote neurons to survive by shifting their physiology from maintaining structure and supporting synaptic transmission towards a regenerative phenotype. We reviewed the putative mechanisms involved in miRNA mediated post-transcriptional regulation and pointed out several areas where future research is necessary to advance our understanding of how targeting miRNA machinery can be used as a therapeutic approach for treating nerve injuries.
Collapse
Affiliation(s)
- Di Wu
- Department of Physiology, East Carolina University Greenville, NC, USA ; Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA
| | | |
Collapse
|
83
|
Xu H, Wu B, Jiang F, Xiong S, Zhang B, Li G, Liu S, Gao Y, Xu C, Tu G, Peng H, Liang S, Xiong H. High fatty acids modulate P2X(7) expression and IL-6 release via the p38 MAPK pathway in PC12 cells. Brain Res Bull 2013; 94:63-70. [PMID: 23438872 DOI: 10.1016/j.brainresbull.2013.02.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 02/12/2013] [Accepted: 02/13/2013] [Indexed: 01/01/2023]
Abstract
Diabetic neuropathy (DNP) is the most common chronic complication of diabetes. Elevated free fatty acids (FFAs) have been recently recognized as a major cause of nervous system damage in diabetes. P2X receptors play a primary role in regulation of neuronal interleukin (IL)-6 release, which is of paramount relevance to the functional changes of nerve system. The present study aimed to investigate the effects of high FFAs on the P2X7 expression and IL-6 release in PC12 cells. High FFAs induced P2X7 expression and IL-6 release significantly in PC12 cells. Moreover, high FFAs enhanced ATP or BzATP-induced Ca(2+) signals in PC12 cells. Inhibition of P2X7 by transfection with P2X7-siRNA or co-culture with BBG (a specific P2X7 inhibitor) at high concentrations of FFAs decreased ATP or BzATP-promoted Ca(2+) signals and IL-6 release in PC12 cells. High FFAs induced the phosphorylation of p38 in PC12 cells. Blockade of p38 pathways by SB-203580 inhibited P2X7 up-expression, ATP or BzATP-evoked [Ca(2+)]i rises as well as IL-6 release in PC12 cells exposed to high FFAs. Therefore, high concentrations of FFAs increased the expression of P2X7 in PC12 cells via activation of p38 mitogen-activated protein kinase (MAPK) signaling pathway, which contributed to P2X7-mediated IL-6 release from PC12 cells.
Collapse
Affiliation(s)
- Hong Xu
- Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006, PR China
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
84
|
Role of inflammation and cytokines in peripheral nerve regeneration. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 108:173-206. [PMID: 24083435 DOI: 10.1016/b978-0-12-410499-0.00007-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This chapter provides a review of immune reactions involved in classic as well as alternative methods of peripheral nerve regeneration, and mainly with a view to understanding their beneficial effects. Axonal degeneration distal to nerve damage triggers a cascade of inflammatory events alongside injured nerve fibers known as Wallerian degeneration (WD). The early inflammatory reactions of WD comprise the complement system, arachidonic acid metabolites, and inflammatory mediators that are related to myelin fragmentation and activation of Schwann cells. Fine-tuned upregulation of the cytokine/chemokine network by Schwann cells activates resident and hematogenous macrophages to complete the clearance of axonal and myelin debris and stimulate regrowth of axonal sprouts. In addition to local effects, immune reactions of neuronal bodies and glial cells are also implicated in the survival and conditioning of neurons to regenerate severed nerves. Understanding of the cellular and molecular interactions between the immune system and peripheral nerve injury opens new possibilities for targeting inflammatory mediators to improve functional reinnervation.
Collapse
|
85
|
Cytokines that promote nerve regeneration. Exp Neurol 2012; 238:101-6. [PMID: 22981450 DOI: 10.1016/j.expneurol.2012.08.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/01/2012] [Accepted: 08/11/2012] [Indexed: 11/21/2022]
|