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Li L, Ni L, Heary RF, Elkabes S. Astroglial TLR9 antagonism promotes chemotaxis and alternative activation of macrophages via modulation of astrocyte-derived signals: implications for spinal cord injury. J Neuroinflammation 2020; 17:73. [PMID: 32098620 PMCID: PMC7041103 DOI: 10.1186/s12974-020-01748-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 02/13/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The recruitment of immune system cells into the central nervous system (CNS) has a profound effect on the outcomes of injury and disease. Glia-derived chemoattractants, including chemokines, play a pivotal role in this process. In addition, cytokines and chemokines influence the phenotype of infiltrating immune cells. Depending on the stimuli present in the local milieu, infiltrating macrophages acquire the classically activated M1 or alternatively activated M2 phenotypes. The polarization of macrophages into detrimental M1 versus beneficial M2 phenotypes significantly influences CNS pathophysiology. Earlier studies indicated that a toll-like receptor 9 (TLR9) antagonist modulates astrocyte-derived cytokine and chemokine release. However, it is not known whether these molecular changes affect astrocyte-induced chemotaxis and polarization of macrophages. The present studies were undertaken to address these issues. METHODS The chemotaxis and polarization of mouse peritoneal macrophages by spinal cord astrocytes were evaluated in a Transwell co-culture system. Arrays and ELISA were utilized to quantify chemokines in the conditioned medium (CM) of pure astrocyte cultures. Immunostaining for M1- and M2-specific markers characterized the macrophage phenotype. The percentage of M2 macrophages at the glial scar was determined by stereological approaches in mice sustaining a mid-thoracic spinal cord contusion injury (SCI) and intrathecally treated with oligodeoxynucleotide 2088 (ODN 2088), the TLR9 antagonist. Statistical analyses used two-tailed independent-sample t-test and one-way analysis of variance (ANOVA) followed by Tukey's post hoc test. A p value < 0.05 was considered to be statistically significant. RESULTS ODN 2088-treated astrocytes significantly increased the chemotaxis of peritoneal macrophages via release of chemokine (C-C motif) ligand 1 (CCL1). Vehicle-treated astrocytes polarized macrophages into the M2 phenotype and ODN 2088-treated astrocytes promoted further M2 polarization. Reduced CCL2 and CCL9 release by astrocytes in response to ODN 2088 facilitated the acquisition of the M2 phenotype, suggesting that CCL2 and CCL9 are negative regulators of M2 polarization. The percentage of M2 macrophages at the glial scar was higher in mice sustaining a SCI and receiving ODN 2088 treatment as compared to vehicle-treated injured controls. CONCLUSIONS TLR9 antagonism could create a favorable environment during SCI by supporting M2 macrophage polarization and chemotaxis via modulation of astrocyte-to-macrophage signals.
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Affiliation(s)
- Lun Li
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, 205 South Orange Avenue, F-1204, Newark, NJ 07103 USA
| | - Li Ni
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, 205 South Orange Avenue, F-1204, Newark, NJ 07103 USA
| | - Robert F. Heary
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, 205 South Orange Avenue, F-1204, Newark, NJ 07103 USA
| | - Stella Elkabes
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers, The State University of New Jersey, 205 South Orange Avenue, F-1204, Newark, NJ 07103 USA
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Kuthati Y, Busa P, Goutham Davuluri VN, Wong CS. Manganese Oxide Nanozymes Ameliorate Mechanical Allodynia in a Rat Model of Partial Sciatic Nerve-Transection Induced Neuropathic Pain. Int J Nanomedicine 2019; 14:10105-10117. [PMID: 31920306 PMCID: PMC6938959 DOI: 10.2147/ijn.s225594] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 12/16/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Reactive oxygen species (ROS) induced oxidative stress is linked to numerous neurological diseases, including neuropathic pain. Natural ROS scavenging enzymes like superoxide dismutase (SOD) and catalase have been found to be efficient in alleviating neuropathic pain. However, their sensitivity towards extreme pH and a short half-life limit their efficacy in vivo. Manganese oxide nanoparticles (MONPs) are recently known to possess ROS scavenging properties. In this study, MONPs were examined for their therapeutic effect on neuropathic pain. METHODS The MONPs were synthesized by a hydrothermal method. The synthesized MONPs were characterized by UV/Vis, TEM, SEM, FTIR, NTA and XRD. The biocompatibility of the nanoparticles is evaluated in neural cells using LDH assay. MONPs were evaluated for their antioxidant activity by DPPH assay. In addition, in vitro ROS scavenging properties were examined in bone marrow-derived macrophage (BMDM) cells using 2',7'-dichlorofluorescin diacetate (DCFDA) assay. To evaluate the in vivo efficacy of nanoparticles, neuropathic pain was induced in Wistar rats by partial sciatic nerve transection (PSNT). On post-transection days 14 to 18, rats were intrathecally injected with MONPs and paw withdrawal threshold was measured. The spinal cords were collected and processed for Western blotting and histological analysis. RESULTS The synthesized MONPs were biocompatible and showed effective antioxidant activity against DPPH free radical scavenging. Further, the nanoparticles scavenged ROS efficiently in vitro in BMDM and their intrathecal administration significantly reduced mechanical allodynia as well as the expression of cyclooxygenase-2 (COX-2), an important mediator of chronic and inflammatory pain in the spinal dorsal horns of PSNT rats. CONCLUSION As ROS play a significant role in neuropathic pain, we expect that MONPs could be a promising tool for the treatment of various inflammatory diseases and might also serve as a potential nanocarrier for the delivery of analgesics.
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Affiliation(s)
- Yaswanth Kuthati
- Department of Anesthesiology, Cathy General Hospital, Taipei, Taiwan
| | - Prabhakar Busa
- Department of Life Sciences, National Dong Hwa University, Hualien, Taiwan
| | | | - Chih Shung Wong
- Department of Anesthesiology, Cathy General Hospital, Taipei, Taiwan
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Lin YF, Xie Z, Zhou J, Yin G, Lin HD. Differential gene and protein expression between rat tibial nerve and common peroneal nerve during Wallerian degeneration. Neural Regen Res 2019; 14:2183-2191. [PMID: 31397358 PMCID: PMC6788246 DOI: 10.4103/1673-5374.262602] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Wallerian degeneration and nerve regeneration after injury are complex processes involving many genes, proteins and cytokines. After different peripheral nerve injuries the regeneration rate can differ. Whether this is caused by differential expression of genes and proteins during Wallerian degeneration remains unclear. The right tibial nerve and the common peroneal nerve of the same rat were exposed and completely cut through and then sutured in the same horizontal plane. On days 1, 7, 14, and 21 after surgery, 1–2 cm of nerve tissue distal to the suture site was dissected out from the tibial and common peroneal nerves. The differences in gene and protein expression during Wallerian degeneration of the injured nerves were then studied by RNA sequencing and proteomic techniques. In the tibial and common peroneal nerves, there were 1718, 1374, 1187, and 2195 differentially expressed genes, and 477, 447, 619, and 495 differentially expressed proteins on days 1, 7, 14, and 21 after surgery, respectively. Forty-seven pathways were activated during Wallerian degeneration. Three genes showing significant differential expression by RNA sequencing (Hoxd4, Lpcat4 and Tbx1) were assayed by real-time quantitative polymerase chain reaction. RNA sequencing and real-time quantitative polymerase chain reaction results were consistent. Our findings showed that expression of genes and proteins in injured tibial and the common peroneal nerves were significantly different during Wallerian degeneration at different time points. This suggests that the biological processes during Wallerian degeneration are different in different peripheral nerves after injury. The procedure was approved by the Animal Experimental Ethics Committee of the Second Military Medical University, China (approval No. CZ20160218) on February 18, 2016.
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Affiliation(s)
- Yao-Fa Lin
- Department of Orthopedic Surgery, Changzheng Hospital, the Second Military Medical University, Shanghai, China
| | - Zheng Xie
- Department of Orthopedic Surgery, Changzheng Hospital, the Second Military Medical University, Shanghai, China
| | - Jun Zhou
- Department of Orthopedic Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Gang Yin
- Department of Orthopedic Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hao-Dong Lin
- Department of Orthopedic Surgery, Changzheng Hospital, the Second Military Medical University; Department of Orthopedic Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Hsieh CH, Rau CS, Kuo PJ, Liu SH, Wu CJ, Lu TH, Wu YC, Lin CW. Knockout of toll-like receptor impairs nerve regeneration after a crush injury. Oncotarget 2017; 8:80741-80756. [PMID: 29113341 PMCID: PMC5655236 DOI: 10.18632/oncotarget.20206] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/12/2017] [Indexed: 01/01/2023] Open
Abstract
Background Toll-like receptors (TLRs) are involved in the initiation of Schwann cell activation and subsequent recruitment of macrophages for clearance of degenerated myelin and neuronal debris after nerve injury. The present study was designed to investigate the regenerative outcome and expression of myelination-related factors in Tlr-knockout mice following a sciatic nerve crush injury. Materials and methods A standard sciatic nerve crush injury, induced by applying constant pressure to the nerve with a No. 5 jeweler's forceps for 30 s, was performed in C57BL/6, Tlr2−/−, Tlr3−/−, Tlr4−/−, Tlr5−/−, and Tlr7−/− mice. Quantitative histomorphometric analysis of toluidine blue-stained nerve specimens and walking track analysis were performed to evaluate nerve regeneration outcomes. PCR Arrays were used to detect the expression of neurogenesis-related genes of dorsal root ganglia as well as of myelination-related genes of the distal nerve segments. Results Worse nerve regeneration after nerve crush injury was found in all Tlr-knockout mice than in C57BL/6 mice. Delayed expression of myelin genes and a different expression pattern of myelination-related neurotrophin genes and transcription factors were found in Tlr-knockout mice in comparison to C57BL/6 mice. In these TLR-mediated pathways, insulin-like growth factor 2 and brain-derived neurotrophic factor, as well as early growth response 2 and N-myc downstream-regulated gene 1, were significantly decreased in the early and late stages, respectively, of nerve regeneration after a crush injury. Conclusions Knockout of Tlr genes decreases the expression of myelination-related factors and impairs nerve regeneration after a sciatic nerve crush injury.
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Affiliation(s)
- Ching-Hua Hsieh
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.,Center for Vascularized Composite Allotransplantation, Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Cheng-Shyuan Rau
- Department of Neurosurgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Pao-Jen Kuo
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Shu-Hsuan Liu
- Faculty of Health Sciences, McMaster University, Hamilton, Canada
| | - Chia-Jung Wu
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Tsu-Hsiang Lu
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Yi-Chan Wu
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Chia-Wei Lin
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
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Mietto BS, Mostacada K, Martinez AMB. Neurotrauma and inflammation: CNS and PNS responses. Mediators Inflamm 2015; 2015:251204. [PMID: 25918475 PMCID: PMC4397002 DOI: 10.1155/2015/251204] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/24/2015] [Accepted: 03/09/2015] [Indexed: 01/09/2023] Open
Abstract
Traumatic injury to the central nervous system (CNS) or the peripheral nervous system (PNS) triggers a cascade of events which culminate in a robust inflammatory reaction. The role played by inflammation in the course of degeneration and regeneration is not completely elucidated. While, in peripheral nerves, the inflammatory response is assumed to be essential for normal progression of Wallerian degeneration and regeneration, CNS trauma inflammation is often associated with poor recovery. In this review, we discuss key mechanisms that trigger the inflammatory reaction after nervous system trauma, emphasizing how inflammations in both CNS and PNS differ from each other, in terms of magnitude, cell types involved, and effector molecules. Knowledge of the precise mechanisms that elicit and maintain inflammation after CNS and PNS tissue trauma and their effect on axon degeneration and regeneration is crucial for the identification of possible pharmacological drugs that can positively affect the tissue regenerative capacity.
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Affiliation(s)
- Bruno Siqueira Mietto
- Laboratório de Neurodegeneração e Reparo, Departamento de Patologia, Faculdade de Medicina, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, 21941-550 Rio de Janeiro, RJ, Brazil
| | - Klauss Mostacada
- Laboratório de Neurodegeneração e Reparo, Departamento de Patologia, Faculdade de Medicina, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, 21941-550 Rio de Janeiro, RJ, Brazil
| | - Ana Maria Blanco Martinez
- Laboratório de Neurodegeneração e Reparo, Departamento de Patologia, Faculdade de Medicina, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, 21941-550 Rio de Janeiro, RJ, Brazil
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Gong L, Zhu Y, Xu X, Li H, Guo W, Zhao Q, Yao D. The effects of claudin 14 during early Wallerian degeneration after sciatic nerve injury. Neural Regen Res 2014; 9:2151-8. [PMID: 25657736 PMCID: PMC4316448 DOI: 10.4103/1673-5374.147946] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2014] [Indexed: 12/16/2022] Open
Abstract
Claudin 14 has been shown to promote nerve repair and regeneration in the early stages of Wallerian degeneration (0-4 days) in rats with sciatic nerve injury, but the mechanism underlying this process remains poorly understood. This study reported the effects of claudin 14 on nerve degeneration and regeneration during early Wallerian degeneration. Claudin 14 expression was up-regulated in sciatic nerve 4 days after Wallerian degeneration. The altered expression of claudin 14 in Schwann cells resulted in expression changes of cytokines in vitro. Expression of claudin 14 affected c-Jun, but not Akt and ERK1/2 pathways. Further studies revealed that enhanced expression of claudin 14 could promote Schwann cell proliferation and migration. Silencing of claudin 14 expression resulted in Schwann cell apoptosis and reduction in Schwann cell proliferation. Our data revealed the role of claudin 14 in early Wallerian degeneration, which may provide new insights into the molecular mechanisms of Wallerian degeneration.
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Affiliation(s)
- Leilei Gong
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong, Jiangsu Province, China
| | - Yun Zhu
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong, Jiangsu Province, China
| | - Xi Xu
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong, Jiangsu Province, China
| | - Huaiqin Li
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong, Jiangsu Province, China
| | - Weimin Guo
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong, Jiangsu Province, China
| | - Qin Zhao
- Key Laboratory of People's Liberation Army, Institute of Orthopedics, Chinese PLA General Hospital, Beijing, China
| | - Dengbing Yao
- Jiangsu Key Laboratory of Neuroregeneration, Co-innovation Center of Neuroregeneration, Nantong, Jiangsu Province, China
- School of Life Sciences, Nantong University, Nantong, Jiangsu Province, China
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Stokes JA, Cheung J, Eddinger K, Corr M, Yaksh TL. Toll-like receptor signaling adapter proteins govern spread of neuropathic pain and recovery following nerve injury in male mice. J Neuroinflammation 2013; 10:148. [PMID: 24321498 PMCID: PMC3896749 DOI: 10.1186/1742-2094-10-148] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 11/18/2013] [Indexed: 02/06/2023] Open
Abstract
Background Spinal Toll-like receptors (TLRs) and signaling intermediaries have been implicated in persistent pain states. We examined the roles of two major TLR signaling pathways and selected TLRs in a mononeuropathic allodynia. Methods L5 spinal nerve ligation (SNL) was performed in wild type (WT, C57BL/6) male and female mice and in male Tlr2-/-Tlr3-/-, Tlr4-/-, Tlr5-/-, Myd88-/-, Triflps2, Myd88/Triflps2, Tnf-/-, and Ifnar1-/- mice. We also examined L5 ligation in Tlr4-/- female mice. We examined tactile allodynia using von Frey hairs. Iba-1 (microglia) and GFAP (astrocytes) were assessed in spinal cords by immunostaining. Tactile thresholds were analyzed by 1- and 2-way ANOVA and the Bonferroni post hoc test was used. Results In WT male and female mice, SNL lesions resulted in a persistent and robust ipsilateral, tactile allodynia. In males with TLR2, 3, 4, or 5 deficiencies, tactile allodynia was significantly, but incompletely, reversed (approximately 50%) as compared to WT. This effect was not seen in female Tlr4-/- mice. Increases in ipsilateral lumbar Iba-1 and GFAP were seen in mutant and WT mice. Mice deficient in MyD88, or MyD88 and TRIF, showed an approximately 50% reduction in withdrawal thresholds and reduced ipsilateral Iba-1. In contrast, TRIF and interferon receptor null mice developed a profound ipsilateral and contralateral tactile allodynia. In lumbar sections of the spinal cords, we observed a greater increase in Iba-1 immunoreactivity in the TRIF-signaling deficient mice as compared to WT, but no significant increase in GFAP. Removing MyD88 abrogated the contralateral allodynia in the TRIF signaling-deficient mice. Conversely, IFNβ, released downstream to TRIF signaling, administered intrathecally, temporarily reversed the tactile allodynia. Conclusions These observations suggest a critical role for the MyD88 pathway in initiating neuropathic pain, but a distinct role for the TRIF pathway and interferon in regulating neuropathic pain phenotypes in male mice.
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Affiliation(s)
| | | | | | | | - Tony L Yaksh
- Department of Pharmacology, University of California, 9500 Gilman Dr, MC 0636, La Jolla, San Diego, CA 92093-0636, USA.
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Wu SC, Rau CS, Lu TH, Wu CJ, Wu YC, Tzeng SL, Chen YC, Hsieh CH. Knockout of TLR4 and TLR2 impair the nerve regeneration by delayed demyelination but not remyelination. J Biomed Sci 2013; 20:62. [PMID: 23984978 PMCID: PMC3765918 DOI: 10.1186/1423-0127-20-62] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/27/2013] [Indexed: 01/09/2023] Open
Abstract
Background Knockout of either toll-like receptor 4 (TLR4) or 2 (TLR2) had been reported to delay the Wallerian degeneration after peripheral nerve injury by deterring the recruitment of the macrophages and clearance of myelin debris. However, the impact on the remyelination process is poorly understood. In this study, the effect of TLR2 and TLR4 knockout on the nerve regeneration and on the remyelination process was studied in a mouse model of sciatic nerve crush injury. Results A standard sciatic nerve crush injury by a No. 5 Jeweler forcep for consistent 30 seconds was performed in Tlr4−/− (B6.B10ScN-Tlr4lps-del/JthJ), Tlr2−/− (B6.129-Tlr2tm1Kir/J) and C57BL/6 mice. One centimeter of nerve segment distal to the crushed site was harvested for western blot analysis of the myelin structure protein myelin protein zero (Mpz) and the remyelination transcription factors Oct6 and Sox10 at day 0, 3, 7, 10, 14, 17, 21, 28. Nerve segment 5-mm distal to injured site from additional groups of mice at day 10 after crush injury were subjected to semi-thin section and toluidine blue stain for a quantitative histomorphometric analysis. With less remyelinated nerves and more nerve debris, the histomorphometric analysis revealed a worse nerve regeneration following the sciatic nerve crush injury in both Tlr4−/− and Tlr2−/− mice than the C57BL/6 mice. Although there was a delayed expression of Sox10 but not Oct6 during remyelination, with an average 4-day delay in the demyelination process, the subsequent complete formation of Mpz during remyelination was also delayed for 4 days, implying that the impaired nerve regeneration was mainly attributed to the delayed demyelination process. Conclusions Both TLR4 and TLR2 are crucial for nerve regeneration after nerve crush injury mainly by delaying the demyelination but not the remyelination process.
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Affiliation(s)
- Shao-Chun Wu
- Department of Plastic and Reconstructive Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, No, 123, Ta-Pei Road, Niao-Sung District, Kaohsiung City, 833, Taiwan.
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Yao D, Li M, Shen D, Ding F, Lu S, Zhao Q, Gu X. Expression changes and bioinformatic analysis of Wallerian degeneration after sciatic nerve injury in rat. Neurosci Bull 2013; 29:321-32. [PMID: 23700281 PMCID: PMC5561847 DOI: 10.1007/s12264-013-1340-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 09/21/2012] [Indexed: 12/22/2022] Open
Abstract
Wallerian degeneration (WD) remains an important research topic. Many genes are differentially expressed during the process of WD, but the precise mechanisms responsible for these differentiations are not completely understood. In this study, we used microarrays to analyze the expression changes of the distal nerve stump at 0, 1, 4, 7, 14, 21 and 28 days after sciatic nerve injury in rats. The data revealed 6 076 differentially-expressed genes, with 23 types of expression, specifically enriched in genes associated with nerve development and axonogenesis, cytokine biosynthesis, cell differentiation, cytokine/chemokine production, neuron differentiation, cytokinesis, phosphorylation and axon regeneration. Kyoto Encyclopedia of Genes and Genomes pathway analysis gave findings related mainly to the MAPK signaling pathway, the Jak-STAT signaling pathway, the cell cycle, cytokine-cytokine receptor interaction, the p53 signaling pathway and the Wnt signaling pathway. Some key factors were NGF, MAG, CNTF, CTNNA2, p53, JAK2, PLCB1, STAT3, BDNF, PRKC, collagen II, FGF, THBS4, TNC and c-Src, which were further validated by real-time quantitative PCR, Western blot, and immunohistochemistry. Our findings contribute to a better understanding of the functional analysis of differentially-expressed genes in WD and may shed light on the molecular mechanisms of nerve degeneration and regeneration.
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Affiliation(s)
- Dengbing Yao
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019 China
- School of Life Sciences, Nantong University, Nantong, 226019 China
| | - Meiyuan Li
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019 China
| | - Dingding Shen
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019 China
| | - Fei Ding
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019 China
| | - Shibi Lu
- Key Laboratory of the People’s Liberation Army, Institute of Orthopaedics, Chinese PLA General Hospital, Beijing, 100853 China
| | - Qing Zhao
- Key Laboratory of the People’s Liberation Army, Institute of Orthopaedics, Chinese PLA General Hospital, Beijing, 100853 China
| | - Xiaosong Gu
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, 226019 China
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Li M, Guo W, Zhang P, Li H, Gu X, Yao D. Signal flow and pathways in response to early Wallerian degeneration after rat sciatic nerve injury. Neurosci Lett 2013; 536:56-63. [DOI: 10.1016/j.neulet.2013.01.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Accepted: 01/02/2013] [Indexed: 10/27/2022]
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Abstract
Toll-like receptors (TLRs) are germline-encoded pattern-recognition receptors that initiate innate immune responses by recognizing molecular structures shared by a wide range of pathogens, known as pathogen-associated molecular patterns (PAMPs). After tissue injury or cellular stress, TLRs also detect endogenous ligands known as danger-associated molecular patterns (DAMPs). TLRs are expressed in both non-neuronal and neuronal cell types in the central nervous system (CNS) and contribute to both infectious and non-infectious disorders in the CNS. Following tissue insult and nerve injury, TLRs (such as TLR2, TLR3, and TLR4) induce the activation of microglia and astrocytes and the production of the proinflammatory cytokines in the spinal cord, leading to the development and maintenance of inflammatory pain and neuropathic pain. In particular, primary sensory neurons, such as nociceptors, express TLRs (e.g., TLR4 and TLR7) to sense exogenous PAMPs and endogenous DAMPs released after tissue injury and cellular stress. These neuronal TLRs are new players in the processing of pain and itch by increasing the excitability of primary sensory neurons. Given the prevalence of chronic pain and itch and the suffering of affected people, insights into TLR signaling in the nervous system will open a new avenue for the management of clinical pain and itch.
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Yao D, Li M, Shen D, Ding F, Lu S, Zhao Q, Gu X. Gene expression profiling of the rat sciatic nerve in early Wallerian degeneration after injury. Neural Regen Res 2012; 7:1285-92. [PMID: 25657657 PMCID: PMC4308797 DOI: 10.3969/j.issn.1673-5374.2012.17.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 04/23/2012] [Indexed: 11/18/2022] Open
Abstract
Wallerian degeneration is an important area of research in modern neuroscience. A large number of genes are differentially regulated in the various stages of Wallerian degeneration, especially during the early response. In this study, we analyzed gene expression in early Wallerian degeneration of the distal nerve stump at 0, 0.5, 1, 6, 12 and 24 hours after rat sciatic nerve injury using gene chip microarrays. We screened for differentially-expressed genes and gene expression patterns. We examined the data for Gene Ontology, and explored the Kyoto Encyclopedia of Genes and Genomes Pathway. This allowed us to identify key regulatory factors and recurrent network motifs. We identified 1 546 differentially-expressed genes and 21 distinct patterns of gene expression in early Wallerian degeneration, and an enrichment of genes associated with the immune response, acute inflammation, apoptosis, cell adhesion, ion transport and the extracellular matrix. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed components involved in the Jak-STAT, ErbB, transforming growth factor-β, T cell receptor and calcium signaling pathways. Key factors included interleukin-6, interleukin-1, integrin, c-sarcoma, carcinoembryonic antigen-related cell adhesion molecules, chemokine (C-C motif) ligand, matrix metalloproteinase, BH3 interacting domain death agonist, baculoviral IAP repeat-containing 3 and Rac. The data were validated with real-time quantitative PCR. This study provides a global view of gene expression profiles in early Wallerian degeneration of the rat sciatic nerve. Our findings provide insight into the molecular mechanisms underlying early Wallerian degeneration, and the regulation of nerve degeneration and regeneration.
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Affiliation(s)
- Dengbing Yao
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226019, Jiangsu Province, China
- School of Life Sciences, Nantong University, Nantong 226019, Jiangsu Province, China
| | - Meiyuan Li
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226019, Jiangsu Province, China
| | - Dingding Shen
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226019, Jiangsu Province, China
| | - Fei Ding
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226019, Jiangsu Province, China
| | - Shibi Lu
- Key Laboratory of People's Liberation Army, Institute of Orthopedics, Chinese PLA General Hospital, Beijing 100853, China
| | - Qin Zhao
- Key Laboratory of People's Liberation Army, Institute of Orthopedics, Chinese PLA General Hospital, Beijing 100853, China
| | - Xiaosong Gu
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226019, Jiangsu Province, China
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Mao-Ying QL, Wang XW, Yang CJ, Li X, Mi WL, Wu GC, Wang YQ. Robust spinal neuroinflammation mediates mechanical allodynia in Walker 256 induced bone cancer rats. Mol Brain 2012; 5:16. [PMID: 22607655 PMCID: PMC3443428 DOI: 10.1186/1756-6606-5-16] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Accepted: 05/02/2012] [Indexed: 12/31/2022] Open
Abstract
It has been reported that remarkable and sustained activation of astrocytes and/or microglia occurs in cancer induced pain (CIP), which is different from neuropathic and inflammatory pain. The present study was designed to investigate the role of spinal Toll-like receptor 4 (TLR4) induced glial neuroinflammation in cancer induced pain using a modified rat model of bone cancer. The rat model of CIP consisted of unilateral intra-tibial injection with Walker 256 mammary gland carcinoma. Nine days after Walker 256 inoculation, a robust activation of both astrocytes and microglia in bilateral spinal dorsal horn was observed together with significant bilateral mechanical allodynia. This neuroinflammation was characterized by enhanced immunostaining of both glial fibrillary acidic protein (GFAP, astrocyte marker) and OX-42 (microglia marker), and an elevated level of IL-1β, IL-6 and TNF-α mRNA. I.t. administration of fluorocitrate (an inhibitor of glial metabolism, 1 nmol) or minocycline (an inhibitor of microglia, 100 μg) has significant anti-allodynic effects on day 12 after Walker 256 inoculation. Naloxone (a nonstereoselective TLR4 signaling blocker, 60 μg, i.t.) also significantly alleviated mechanical allodynia and simultaneously blocked the increased inflammatory cytokine mRNA. The results suggested that spinal TLR4 might play an important role in the sustained glial activation that critically contributed to the robust and sustained spinal neuroinflammation in CIP. This result could potentially help clinicians and researchers to better understand the mechanism of complicated cancer pain.
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Affiliation(s)
- Qi-Liang Mao-Ying
- Department of Integrative Medicine and Neurobiology, Shanghai Medical College, Institute of Acupuncture Research, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
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Nicotra L, Loram LC, Watkins LR, Hutchinson MR. Toll-like receptors in chronic pain. Exp Neurol 2011; 234:316-29. [PMID: 22001158 DOI: 10.1016/j.expneurol.2011.09.038] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 09/26/2011] [Accepted: 09/30/2011] [Indexed: 12/16/2022]
Abstract
Proinflammatory central immune signaling contributes significantly to the initiation and maintenance of heightened pain states. Recent discoveries have implicated the innate immune system, pattern recognition Toll-like receptors in triggering these proinflammatory central immune signaling events. These exciting developments have been complemented by the discovery of neuronal expression of Toll-like receptors, suggesting pain pathways can be activated directly by the detection of pathogen associated molecular patterns or danger associated molecular patterns. This review will examine the evidence to date implicating Toll-like receptors and their associated signaling components in heightened pain states. In addition, insights into the impact Toll-like receptors have on priming central immune signaling systems for heightened pain states will be discussed. The influence possible sex differences in Toll-like receptor signaling have for female pain and the recognition of small molecule xenobiotics by Toll-like receptors will also be reviewed.
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Affiliation(s)
- Lauren Nicotra
- Discipline of Pharmacology, School of Medical Sciences, University of Adelaide, South Australia, 5005, Australia
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Stokes JA, Corr M, Yaksh TL. Transient tactile allodynia following intrathecal puncture in mouse: contributions of Toll-like receptor signaling. Neurosci Lett 2011; 504:215-8. [PMID: 21964382 DOI: 10.1016/j.neulet.2011.09.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 09/12/2011] [Accepted: 09/13/2011] [Indexed: 12/11/2022]
Abstract
Studies of spinal drug action in mice often involve percutaneous intrathecal drug administration delivered in a lightly anesthetized animal. A successful lumbar intrathecal (IT) needle stick of a lightly anesthetized (isoflurane) mouse evokes a tail flick, which is an indication of local spinal nerve stimulation. Immediately upon arousal, a hind paw tactile allodynia, as measured with von Frey hairs (pre 1.55±0.11 g vs. injected 0.66±0.08 g) lasts 3-4 h. In a similarly anesthetized mouse without the needle stick, a 1-h allodynia was noted. In studies on spinal Toll-like receptor (TLR) signaling, we observed that following intrathecal puncture and mechanical stimulation of the nerve roots mice deficient in TLR down-stream signaling (Myd88(-/-)/Trif(lps2)), displayed only the transient (1-h) allodynia otherwise observed following isoflurane alone. These data suggest that the extended period of hyperalgesia observed with needle penetration of the dura and mechanical stimulation of the nerve roots requires signaling through the MyD88/TRIF pathways and supports the intrinsic role of Toll-like receptors in the allodynia secondary to the minor nerve activation occurring during the intradural puncture.
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Affiliation(s)
- Jennifer A Stokes
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0818, USA
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