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Funnell JL, Fougere J, Zahn D, Dutz S, Gilbert RJ. Delivery of TGFβ3 from Magnetically Responsive Coaxial Fibers Reduces Spinal Cord Astrocyte Reactivity In Vitro. Adv Biol (Weinh) 2024:e2300531. [PMID: 38935534 DOI: 10.1002/adbi.202300531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 03/29/2024] [Indexed: 06/29/2024]
Abstract
A spinal cord injury (SCI) compresses the spinal cord, killing neurons and glia at the injury site and resulting in prolonged inflammation and scarring that prevents regeneration. Astrocytes, the main glia in the spinal cord, become reactive following SCI and contribute to adverse outcomes. The anti-inflammatory cytokine transforming growth factor beta 3 (TGFβ3) has been shown to mitigate astrocyte reactivity; however, the effects of prolonged TGFβ3 exposure on reactive astrocyte phenotype have not yet been explored. This study investigates whether magnetic core-shell electrospun fibers can be used to alter the release rate of TGFβ3 using externally applied magnetic fields, with the eventual application of tailored drug delivery based on SCI severity. Magnetic core-shell fibers are fabricated by incorporating superparamagnetic iron oxide nanoparticles (SPIONs) into the shell and TGFβ3 into the core solution for coaxial electrospinning. Magnetic field stimulation increased the release rate of TGFβ3 from the fibers by 25% over 7 days and released TGFβ3 reduced gene expression of key astrocyte reactivity markers by at least twofold. This is the first study to magnetically deliver bioactive proteins from magnetic fibers and to assess the effect of sustained release of TGFβ3 on reactive astrocyte phenotype.
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Affiliation(s)
- Jessica L Funnell
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th St, Troy, NY, 12180, USA
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 15th St., Troy, NY, 12180, USA
| | - Jasper Fougere
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th St, Troy, NY, 12180, USA
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 15th St., Troy, NY, 12180, USA
| | - Diana Zahn
- Institut für Biomedizinische Technik und Informatik, Technische Universität Ilmenau, Gustav-Kirchhoff-Str. 2, 98693, Ilmenau, Germany
| | - Silvio Dutz
- Institut für Biomedizinische Technik und Informatik, Technische Universität Ilmenau, Gustav-Kirchhoff-Str. 2, 98693, Ilmenau, Germany
- Westsächsische Hochschule Zwickau, Kornmarkt 1, 08056, Zwickau, Germany
| | - Ryan J Gilbert
- Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th St, Troy, NY, 12180, USA
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 15th St., Troy, NY, 12180, USA
- Albany Stratton Veteran Affairs Medical Center, 113 Holland Ave., Albany, NY, 12208, USA
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2
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Hosen S, Ikeda-Yorifuji I, Yamashita T. Asporin and CD109, expressed in the injured neonatal spinal cord, attenuate axonal re-growth in vitro. Neurosci Lett 2024; 833:137832. [PMID: 38796094 DOI: 10.1016/j.neulet.2024.137832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 05/17/2024] [Accepted: 05/22/2024] [Indexed: 05/28/2024]
Abstract
Axonal regeneration is restricted in adults and causes irreversible motor dysfunction following spinal cord injury (SCI). In contrast, neonates have prominent regenerative potential and can restore their neural function. Although the distinct cellular responses in neonates have been studied, how they contribute to neural recovery remains unclear. To assess whether the secreted molecules in neonatal SCI can enhance neural regeneration, we re-analyzed the previously performed single-nucleus RNA-seq (snRNA-seq) and focused on Asporin and Cd109, the highly expressed genes in the injured neonatal spinal cord. In the present study, we showed that both these molecules were expressed in the injured spinal cords of adults and neonates. We treated the cortical neurons with recombinant Asporin or CD109 to observe their direct effects on neurons in vitro. We demonstrated that these molecules enhance neurite outgrowth in neurons. However, these molecules did not enhance re-growth of severed axons. Our results suggest that Asporin and CD109 influence neurites at the lesion site, rather than promoting axon regeneration, to restore neural function in neonates after SCI.
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Affiliation(s)
- Sakura Hosen
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Iyo Ikeda-Yorifuji
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan.
| | - Toshihide Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan; WPI Immunology Frontier Research Center, Osaka University, Suita, Japan; Department of Molecular Neuroscience, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan; Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, Suita, Japan.
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3
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Chen T, He X, Wang J, Du D, Xu Y. NT-3 Combined with TGF-β Signaling Pathway Enhance the Repair of Spinal Cord Injury by Inhibiting Glial Scar Formation and Promoting Axonal Regeneration. Mol Biotechnol 2024; 66:1484-1495. [PMID: 37318740 PMCID: PMC11101526 DOI: 10.1007/s12033-023-00781-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 05/24/2023] [Indexed: 06/16/2023]
Abstract
This study investigated the mechanism of neurotrophin-3 (NT-3) in promoting spinal cord injury repair through the transforming growth factor-beta (TGF-β) signaling pathway. A mouse model of spinal cord injury was established. Forty C57BL/6J mice were randomized into model, NT-3, NT-3 + TGF-β1 and NT-3 + LY364947 groups. The Basso-Beattie-Bresnahan (BBB) scores of the NT-3 and NT-3 + LY364947 groups were significantly higher than the model group. The BBB score of the NT-3 + TGF-β1 group was significantly lower than NT-3 group. Hematoxylin-eosin staining and transmission electron microscopy showed reduction in myelin sheath injury, more myelinated nerve fibers in the middle section of the catheter, and relatively higher density and more neatly arranged regenerated axons in the NT-3 and NT-3 + LY364947 groups compared with the model and NT-3 + TGF-β1 groups. Immunofluorescence, TUNEL and Western blot analysis showed that compared with model group, the NEUN expression increased, and the apoptosis and Col IV, LN, CSPG, tenascin-C, Sema 3 A, EphB2 and Smad2/3 protein expression decreased significantly in the NT-3 and NT-3 + LY364947 groups; the condition was reversed in the NT-3 + TGF-β1 group compared with the NT-3 group. NT-3 combined with TGF-β signaling pathway promotes astrocyte differentiation, reduces axon regeneration inhibitory molecules, apoptosis and glial scar formation, promotes axon regeneration, and improves spinal cord injury.
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Affiliation(s)
- Taibang Chen
- Department of Orthopedics, No. 920 Hospital of PLA Joint Logistics Support Force, No. 212 Daguanlu, Kunming, Yunnan, 650000, China.
| | - Xiaoqing He
- Department of Orthopedics, No. 920 Hospital of PLA Joint Logistics Support Force, No. 212 Daguanlu, Kunming, Yunnan, 650000, China
| | - Jing Wang
- Department of Orthopedics, No. 920 Hospital of PLA Joint Logistics Support Force, No. 212 Daguanlu, Kunming, Yunnan, 650000, China
| | - Di Du
- Department of Orthopedics, No. 920 Hospital of PLA Joint Logistics Support Force, No. 212 Daguanlu, Kunming, Yunnan, 650000, China
| | - Yongqing Xu
- Department of Orthopedics, No. 920 Hospital of PLA Joint Logistics Support Force, No. 212 Daguanlu, Kunming, Yunnan, 650000, China.
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4
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Huang Y, Liu R, Meng T, Zhang B, Ma J, Liu X. The TGFβ1/SMADs/Snail1 signaling axis mediates pericyte-derived fibrous scar formation after spinal cord injury. Int Immunopharmacol 2024; 128:111482. [PMID: 38237223 DOI: 10.1016/j.intimp.2023.111482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/20/2023] [Accepted: 12/31/2023] [Indexed: 02/08/2024]
Abstract
AIMS The deposition of fibrous scars after spinal cord injury (SCI) affects axon regeneration and the recovery of sensorimotor function. It has been reported that microvascular pericytes in the neurovascular unit are the main source of myofibroblasts after SCI, but the specific molecular targets that regulate pericyte participation in the formation of fibrous scars remain to be clarified. METHODS In this study, a rat model of spinal cord dorsal hemisection injury was used. After SCI, epigallocatechin gallate (EGCG) was intraperitoneally injected to block the TGFβ1 signaling pathway or LV-Snail1-shRNA was immediately injected near the core of the injury using a microsyringe to silence Snail1 expression. Western blotting and RT-qPCR were used to analyze protein expression and transcription levels in tissues. Nissl staining and immunofluorescence analysis were used to analyze neuronal cell viability, scar tissue, and axon regeneration after SCI. Finally, the recovery of hind limb function after SCI was evaluated. RESULTS The results showed that targeted inhibition of Snail1 could block TGFβ1-induced pericyte-myofibroblast differentiation in vitro. In vivo experiments showed that timely blockade of Snail1 could reduce fibrous scar deposition after SCI, promote axon regeneration, improve neuronal survival, and facilitate the recovery of lower limb motor function. CONCLUSION In summary, Snail1 promotes the deposition of fibrous scars and inhibits axonal regeneration after SCI by inducing the differentiation of pericytes into myofibroblasts. Snail1 may be a promising therapeutic target for SCI.
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Affiliation(s)
- Yan Huang
- Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, People 's Republic of China
| | - Renzhong Liu
- Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, People 's Republic of China
| | - Tingyang Meng
- Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, People 's Republic of China
| | - Bin Zhang
- Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, People 's Republic of China
| | - Jingxing Ma
- Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, People 's Republic of China.
| | - Xuqiang Liu
- Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, People 's Republic of China.
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Yang J, Dong J, Li H, Gong Z, Wang B, Du K, Zhang C, Bi H, Wang J, Tian X, Chen L. Circular RNA HIPK2 Promotes A1 Astrocyte Activation after Spinal Cord Injury through Autophagy and Endoplasmic Reticulum Stress by Modulating miR-124-3p-Mediated Smad2 Repression. ACS OMEGA 2024; 9:781-797. [PMID: 38222662 PMCID: PMC10785321 DOI: 10.1021/acsomega.3c06679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/10/2023] [Accepted: 11/24/2023] [Indexed: 01/16/2024]
Abstract
Glial scarring formed by reactive astrocytes after spinal cord injury (SCI) is the primary obstacle to neuronal regeneration within the central nervous system, making them a promising target for SCI treatment. Our previous studies have demonstrated the positive impact of miR-124-3p on neuronal repair, but it remains unclear how miR-124-3p is involved in autophagy or ER stress in astrocyte activation. To answer this question, the expression of A1 astrocyte-related markers at the transcriptional and protein levels after SCI was checked in RNA-sequencing data and verified using quantitative polymerase chain reaction (qPCR) and Western blotting in vitro and in vivo. The potential interactions among circHIPK2, miR-124-3p, and Smad2 were analyzed and confirmed by bioinformatics analyses and a luciferase reporter assay. In the end, the role of miR-124-3p in autophagy, ER stress, and SCI was investigated by using Western blotting to measure key biomarkers (C3, LC3, and Chop) in the absence or presence of corresponding selective inhibitors (siRNA, 4-PBA, TG). As a result, SCI caused the increase of A1 astrocyte markers, in which the upregulated circHIPK2 directly targeted miR-124-3p, and the direct downregulating effect of Smad2 by miR-124-3p was abolished, while Agomir-124 treatment reversed this effect. Injury caused a significant change of markers for ER stress and autophagy through the circHIPK2/miR-124-3p/Smad2 pathway, which might activate the A1 phenotype, and ER stress might promote autophagy in astrocytes. In conclusion, circHIPK2 may play a functional role in sequestering miR-124-3p and facilitating the activation of A1 astrocytes through regulating Smad2-mediated downstream autophagy and ER stress pathways, providing a new perspective on potential targets for functional recovery after SCI.
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Affiliation(s)
| | | | - Haotian Li
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Zhiqiang Gong
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Bing Wang
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Kaili Du
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Chunqiang Zhang
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Hangchuan Bi
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Junfei Wang
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Xinpeng Tian
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
| | - Lingqiang Chen
- Department of Orthopedics, The First Affiliated Hospital of Kunming Medical University, Kunming 650032, Yunnan, China
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6
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Ma CW, Wang ZQ, Ran R, Liao HY, Lyu JY, Ren Y, Lei ZY, Zhang HH. TGF-β signaling pathway in spinal cord injury: Mechanisms and therapeutic potential. J Neurosci Res 2024; 102:e25255. [PMID: 37814990 DOI: 10.1002/jnr.25255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 08/15/2023] [Accepted: 09/24/2023] [Indexed: 10/11/2023]
Abstract
Spinal cord injury (SCI) is a highly disabling central nervous system injury with a complex pathological process, resulting in severe sensory and motor dysfunction. The current treatment modalities only alleviate its symptoms and cannot effectively intervene or treat its pathological process. Many studies have reported that the transforming growth factor (TGF)-β signaling pathway plays an important role in neuronal differentiation, growth, survival, and axonal regeneration after central nervous system injury. Furthermore, the TGF-β signaling pathway has a vital regulatory role in SCI pathophysiology and neural regeneration. Following SCI, regulation of the TGF-β signaling pathway can suppress inflammation, reduce apoptosis, prevent glial scar formation, and promote neural regeneration. Due to its role in SCI, the TGF-β signaling pathway could be a potential therapeutic target. This article reported the pathophysiology of SCI, the characteristics of the TGF-β signaling pathway, the role of the TGF-β signaling pathway in SCI, and the latest evidence for targeting the TGF-β signaling pathway for treating SCI. In addition, the limitations and difficulties in TGF-β signaling pathway research in SCI are discussed, and solutions are provided to address these potential challenges. We hope this will provide a reference for the TGF-β signaling pathway and SCI research, offering a theoretical basis for targeted therapy of SCI.
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Affiliation(s)
- Chun-Wei Ma
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- The Second Clinical Medical College, Lanzhou University, Lanzhou, China
| | - Zhi-Qiang Wang
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- The Second Clinical Medical College, Lanzhou University, Lanzhou, China
| | - Rui Ran
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- The Second Clinical Medical College, Lanzhou University, Lanzhou, China
| | - Hai-Yang Liao
- The Second Clinical Medical College, Lanzhou University, Lanzhou, China
| | - Jia-Yang Lyu
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- The Second Clinical Medical College, Lanzhou University, Lanzhou, China
| | - Yi Ren
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- The Second Clinical Medical College, Lanzhou University, Lanzhou, China
| | - Ze-Yuan Lei
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- The Second Clinical Medical College, Lanzhou University, Lanzhou, China
| | - Hai-Hong Zhang
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, China
- The Second Clinical Medical College, Lanzhou University, Lanzhou, China
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7
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Li Z, Hou X, Liu X, Ma L, Tan J. Hyperbaric Oxygen Therapy-Induced Molecular and Pathway Changes in a Rat Model of Spinal Cord Injury: A Proteomic Analysis. Dose Response 2022; 20:15593258221141579. [PMID: 36458280 PMCID: PMC9706077 DOI: 10.1177/15593258221141579] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2023] Open
Abstract
Hyperbaric Oxygen Therapy (HBOT) has definitive therapeutic effects on spinal cord injury (SCI), but its mechanism of action is still unclear. Here, we've conducted a systemic proteomic analysis to identify differentially expressed proteins (DEPs) between SCI rats and HBOT + SCI rats. The function clustering analysis showed that the top enriched pathways of DEPs include oxygen transport activity, oxygen binding, and regulation of T cell proliferation. The results of functional and signal pathway analyses indicated that metabolic pathways, thermogenesis, LXR/RXR activation, acute phase response signaling, and the intrinsic prothrombin pathway in the SCI + HBOT group was higher than SCI group.
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Affiliation(s)
- Zhuo Li
- Department of Rehabilitation
Medicine, Guangzhou
Xinhua University, Guangzhou,
China
- Hyperbaric Oxygen Department,
Shenzhen
People’s Hospital, Shenzhen,
China
| | - Xiaomin Hou
- Hyperbaric Oxygen Department,
Beijing
Chaoyang Hospital Capital Medical
University, Beijing, China
| | - Xuehua Liu
- Hyperbaric Oxygen Department,
Beijing
Chaoyang Hospital Capital Medical
University, Beijing, China
| | - Linlin Ma
- Hyperbaric Oxygen Department,
Beijing
Chaoyang Hospital Capital Medical
University, Beijing, China
| | - Jiewen Tan
- Department of Rehabilitation
Medicine, Guangzhou
Xinhua University, Guangzhou,
China
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8
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Stewart VD, Cadieux J, Thulasiram MR, Douglas TC, Drewnik DA, Selamat S, Lao Y, Spicer V, Hannila SS. Myelin‐associated glycoprotein alters the neuronal secretome and stimulates the release of
TGFβ
and proteins that affect neural plasticity. FEBS Lett 2022; 596:2952-2973. [DOI: 10.1002/1873-3468.14496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Vanessa D. Stewart
- Department of Human Anatomy and Cell Science University of Manitoba Room 130, Basic Medical Sciences Building, 745 Bannatyne Avenue R3E 0J9 Winnipeg Manitoba Canada
| | - Justine Cadieux
- Department of Human Anatomy and Cell Science University of Manitoba Room 130, Basic Medical Sciences Building, 745 Bannatyne Avenue R3E 0J9 Winnipeg Manitoba Canada
| | - Matsya R. Thulasiram
- Department of Human Anatomy and Cell Science University of Manitoba Room 130, Basic Medical Sciences Building, 745 Bannatyne Avenue R3E 0J9 Winnipeg Manitoba Canada
| | - Tinsley Claire Douglas
- Department of Human Anatomy and Cell Science University of Manitoba Room 130, Basic Medical Sciences Building, 745 Bannatyne Avenue R3E 0J9 Winnipeg Manitoba Canada
| | - Dennis A. Drewnik
- Department of Human Anatomy and Cell Science University of Manitoba Room 130, Basic Medical Sciences Building, 745 Bannatyne Avenue R3E 0J9 Winnipeg Manitoba Canada
| | - Suhaila Selamat
- Department of Human Anatomy and Cell Science University of Manitoba Room 130, Basic Medical Sciences Building, 745 Bannatyne Avenue R3E 0J9 Winnipeg Manitoba Canada
| | - Ying Lao
- Centre for Proteomics and Systems Biology University of Manitoba Room 799, John Buhler Research Centre, 715 McDermot Avenue R3E 3P4 Winnipeg Manitoba Canada
| | - Victor Spicer
- Centre for Proteomics and Systems Biology University of Manitoba Room 799, John Buhler Research Centre, 715 McDermot Avenue R3E 3P4 Winnipeg Manitoba Canada
| | - Sari S. Hannila
- Department of Human Anatomy and Cell Science University of Manitoba Room 130, Basic Medical Sciences Building, 745 Bannatyne Avenue R3E 0J9 Winnipeg Manitoba Canada
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9
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Fibrotic Scar in CNS Injuries: From the Cellular Origins of Fibroblasts to the Molecular Processes of Fibrotic Scar Formation. Cells 2022; 11:cells11152371. [PMID: 35954214 PMCID: PMC9367779 DOI: 10.3390/cells11152371] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/29/2022] [Accepted: 07/30/2022] [Indexed: 02/06/2023] Open
Abstract
Central nervous system (CNS) trauma activates a persistent repair response that leads to fibrotic scar formation within the lesion. This scarring is similar to other organ fibrosis in many ways; however, the unique features of the CNS differentiate it from other organs. In this review, we discuss fibrotic scar formation in CNS trauma, including the cellular origins of fibroblasts, the mechanism of fibrotic scar formation following an injury, as well as the implication of the fibrotic scar in CNS tissue remodeling and regeneration. While discussing the shared features of CNS fibrotic scar and fibrosis outside the CNS, we highlight their differences and discuss therapeutic targets that may enhance regeneration in the CNS.
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10
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Spinal Cord Injury: Pathophysiology, Multimolecular Interactions, and Underlying Recovery Mechanisms. Int J Mol Sci 2020; 21:ijms21207533. [PMID: 33066029 PMCID: PMC7589539 DOI: 10.3390/ijms21207533] [Citation(s) in RCA: 469] [Impact Index Per Article: 117.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/17/2020] [Accepted: 09/24/2020] [Indexed: 12/30/2022] Open
Abstract
Spinal cord injury (SCI) is a destructive neurological and pathological state that causes major motor, sensory and autonomic dysfunctions. Its pathophysiology comprises acute and chronic phases and incorporates a cascade of destructive events such as ischemia, oxidative stress, inflammatory events, apoptotic pathways and locomotor dysfunctions. Many therapeutic strategies have been proposed to overcome neurodegenerative events and reduce secondary neuronal damage. Efforts have also been devoted in developing neuroprotective and neuro-regenerative therapies that promote neuronal recovery and outcome. Although varying degrees of success have been achieved, curative accomplishment is still elusive probably due to the complex healing and protective mechanisms involved. Thus, current understanding in this area must be assessed to formulate appropriate treatment modalities to improve SCI recovery. This review aims to promote the understanding of SCI pathophysiology, interrelated or interlinked multimolecular interactions and various methods of neuronal recovery i.e., neuroprotective, immunomodulatory and neuro-regenerative pathways and relevant approaches.
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11
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TGFβ1 Induces Axonal Outgrowth via ALK5/PKA/SMURF1-Mediated Degradation of RhoA and Stabilization of PAR6. eNeuro 2020; 7:ENEURO.0104-20.2020. [PMID: 32887692 PMCID: PMC7540929 DOI: 10.1523/eneuro.0104-20.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 07/21/2020] [Accepted: 08/06/2020] [Indexed: 12/11/2022] Open
Abstract
Transforming growth factor (TGF)β1 has repeatedly been associated with axonal regeneration and recovery after injury to the CNS. We found TGFβ1 upregulated in the stroke-denervated mouse spinal cord after ischemic injury to the motor cortex as early as 4 d postinjury (dpi) and persisting up to 28 dpi. Given the potential role of TGFβ1 in structural plasticity and functional recovery after stroke highlighted in several published studies, we investigated its downstream signaling in an in vitro model of neurite outgrowth. We found that in this model, TGFβ1 rescues neurite outgrowth under growth inhibitory conditions via the canonical TGFβR2/ALK5 signaling axis. Thereby, protein kinase A (PKA)-mediated phosphorylation of the E3 ubiquitin ligase SMURF1 induces a switch of its substrate preference from PAR6 to the Ras homolog A (RhoA), in this way enhancing outgrowth on the level of the cytoskeleton. This proposed mechanism of TGFβ1 signaling could underly the observed increase in structural plasticity after stroke in vivo as suggested by the temporal and spatial expression of TGFβ1. In accordance with previous publications, this study corroborates the potential of TGFβ1 and associated signaling cascades as a target for future therapeutic interventions to enhance structural plasticity and functional recovery for stroke patients.
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12
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Maksoud E, Liao EH, Haghighi AP. A Neuron-Glial Trans-Signaling Cascade Mediates LRRK2-Induced Neurodegeneration. Cell Rep 2020; 26:1774-1786.e4. [PMID: 30759389 PMCID: PMC6474846 DOI: 10.1016/j.celrep.2019.01.077] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 11/19/2018] [Accepted: 01/19/2019] [Indexed: 12/19/2022] Open
Abstract
Pathogenic mutations in leucine-rich repeat kinase 2 (LRRK2) induce an age-dependent loss of dopaminergic (DA) neurons. We have identified Furin 1, a pro-protein convertase, as a translational target of LRRK2 in DA neurons. Transgenic knockdown of Furin1 or its substrate the bone morphogenic protein (BMP) ligand glass bottom boat (Gbb) protects against LRRK2-induced loss of DA neurons. LRRK2 enhances the accumulation of phosphorylated Mad (pMad) in the nuclei of glial cells in the vicinity of DA neurons but not in DA neurons. Consistently, exposure to paraquat enhances Furin 1 levels in DA neurons and induces BMP signaling in glia. In support of a neuron-glial signaling model, knocking down BMP pathway members only in glia, but not in neurons, can protect against paraquat toxicity. We propose that a neuron-glial BMP-signaling cascade is critical for mediating age-dependent neurodegeneration in two models of Parkinson's disease, thus opening avenues for future therapeutic interventions.
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Affiliation(s)
- Elie Maksoud
- Buck Institute for Research on Aging, Novato, CA 94945, USA
| | - Edward H Liao
- Buck Institute for Research on Aging, Novato, CA 94945, USA
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13
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Li JH, Shi ZJ, Li Y, Pan B, Yuan SY, Shi LL, Hao Y, Cao FJ, Feng SQ. Bioinformatic identification of key candidate genes and pathways in axon regeneration after spinal cord injury in zebrafish. Neural Regen Res 2020; 15:103-111. [PMID: 31535658 PMCID: PMC6862403 DOI: 10.4103/1673-5374.264460] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Zebrafish and human genomes are highly homologous; however, despite this genomic similarity, adult zebrafish can achieve neuronal proliferation, regeneration and functional restoration within 6–8 weeks after spinal cord injury, whereas humans cannot. To analyze differentially expressed zebrafish genes between axon-regenerated neurons and axon-non-regenerated neurons after spinal cord injury, and to explore the key genes and pathways of axonal regeneration after spinal cord injury, microarray GSE56842 was analyzed using the online tool, GEO2R, in the Gene Expression Omnibus database. Gene ontology and protein-protein interaction networks were used to analyze the identified differentially expressed genes. Finally, we screened for genes and pathways that may play a role in spinal cord injury repair in zebrafish and mammals. A total of 636 differentially expressed genes were obtained, including 255 up-regulated and 381 down-regulated differentially expressed genes in axon-regenerated neurons. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment results were also obtained. A protein-protein interaction network contained 480 node genes and 1976 node connections. We also obtained the 10 hub genes with the highest correlation and the two modules with the highest score. The results showed that spectrin may promote axonal regeneration after spinal cord injury in zebrafish. Transforming growth factor beta signaling may inhibit repair after spinal cord injury in zebrafish. Focal adhesion or tight junctions may play an important role in the migration and proliferation of some cells, such as Schwann cells or neural progenitor cells, after spinal cord injury in zebrafish. Bioinformatic analysis identified key candidate genes and pathways in axonal regeneration after spinal cord injury in zebrafish, providing targets for treatment of spinal cord injury in mammals.
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Affiliation(s)
- Jia-He Li
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Zhong-Ju Shi
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Yan Li
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Bin Pan
- Department of Orthopedics, the Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Shi-Yang Yuan
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Lin-Lin Shi
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Yan Hao
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Fu-Jiang Cao
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Shi-Qing Feng
- Department of Orthopedics, Tianjin Medical University General Hospital; Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neurorepair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, China
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14
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Ladak AA, Enam SA, Ibrahim MT. A Review of the Molecular Mechanisms of Traumatic Brain Injury. World Neurosurg 2019; 131:126-132. [PMID: 31301445 DOI: 10.1016/j.wneu.2019.07.039] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 06/30/2019] [Accepted: 07/01/2019] [Indexed: 10/26/2022]
Abstract
Traumatic brain injury (TBI) refers to any insult to the brain resulting in primary (direct) and secondary (indirect) damage to the brain parenchyma. Secondary damage is often linked to the molecular mechanisms that occur post TBI and result in excitotoxicity, neuroinflammation and cytokine damage, oxidative damage, and eventual cell death as prominent mechanisms of cell damage. We present a review highlighting the relation of each of these mechanisms with TBI, their mode of damaging brain tissue, and therapeutic correlation. We also mention the long-term sequelae and their pathophysiology in relation to TBI focusing on Parkinson disease, Alzheimer disease, epilepsy, and chronic traumatic encephalopathy. Understanding of the molecular mechanisms is important in order to realize the secondary and long-term sequelae that follow primary TBI and to devise targeted therapy for quick recovery accordingly.
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Affiliation(s)
- Asma Akbar Ladak
- Medical College, Aga Khan University Hospital, Karachi, Pakistan
| | - Syed Ather Enam
- Section of Neurosurgery, Department of Surgery, Aga Khan University Hospital, Karachi, Pakistan.
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15
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Yuan J, Botchway BOA, Zhang Y, Tan X, Wang X, Liu X. Curcumin Can Improve Spinal Cord Injury by Inhibiting TGF-β-SOX9 Signaling Pathway. Cell Mol Neurobiol 2019; 39:569-575. [PMID: 30915623 DOI: 10.1007/s10571-019-00671-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 03/18/2019] [Indexed: 02/06/2023]
Abstract
Spinal cord injury (SCI) is a severe nervous system disease with high morbidity and disability rate. Signaling pathways play a key role in the neuronal restorative mechanism following SCI. SRY-related high mobility group (HMG)-box gene 9 (SOX9) affects glial scar formation via Transforming growth factor beta (TGF-β) signaling pathway. Activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is transferred into nucleus to upregulate TGF-β-SOX9. Curcumin exhibits potent anti-inflammatory and anti-oxidant properties. Curcumin can play an important role in SCI recovery by inhibiting the expression of NF-κB and TGF-β-SOX9. Herein, we review the potential mechanism of curcumin-inhibiting SOX9 signaling pathway in SCI treatment. The inhibition of NF-κB and SOX9 signaling pathway by curcumin has the potentiality of serving as neuronal regenerative mechanism following SCI.
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Affiliation(s)
- Jiaying Yuan
- Department of Histology and Embryology, Medical College, Shaoxing University, Shaoxing, China
| | - Benson O A Botchway
- Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, China
| | - Yong Zhang
- Department of Histology and Embryology, Medical College, Shaoxing University, Shaoxing, China
| | - Xiaoning Tan
- Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, China
| | - Xizhi Wang
- Department of Histology and Embryology, Medical College, Shaoxing University, Shaoxing, China
| | - Xuehong Liu
- Department of Histology and Embryology, Medical College, Shaoxing University, Shaoxing, China.
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16
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Casault C, Al Sultan AS, Banoei M, Couillard P, Kramer A, Winston BW. Cytokine Responses in Severe Traumatic Brain Injury: Where There Is Smoke, Is There Fire? Neurocrit Care 2019; 30:22-32. [PMID: 29569129 DOI: 10.1007/s12028-018-0522-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This scoping review will discuss the basic functions and prognostic significance of the commonly researched cytokines implicated in severe traumatic brain injury (sTBI), including tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), transforming growth factor-β (TGF-β), substance P, and soluble CD40 ligand (sCD40L). A scoping review was undertaken with an electronic search for articles from the Ovid MEDLINE, PUBMED and EMBASE databases from 1995 to 2017. Inclusion criteria were original research articles, and reviews including both animal models and human clinical studies of acute (< 3 months) sTBI. Selected articles included both isolated sTBI and sTBI with systemic injury. After applying the inclusion criteria and removing duplicates, 141 full-text articles, 126 original research articles and 15 review articles, were evaluated in compiling this review paper. A single reviewer, CC, completed the review in two phases. During the first phase, titles and abstracts of selected articles were reviewed for inclusion. A second evaluation was then conducted on the full text of all selected articles to ensure relevancy. From our current understanding of the literature, it is unlikely a single biomarker will be sufficient in accurately prognosticating patients with sTBI. Intuitively, a more severe injury will demonstrate higher levels of inflammatory cytokines which may correlate as a marker of severe injury. This does not mean, necessarily, these cytokines have a direct and causal role in the poor outcome of the patient. Further research is required to better delineate the complex systemic inflammatory and CNS interactions that occur during sTBI before they can be applied as a reliable prognostic tool.
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Affiliation(s)
- Colin Casault
- Department of Critical Care Medicine, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada. .,Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
| | - Abdulaziz S Al Sultan
- Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Mohammad Banoei
- Department of Critical Care Medicine, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Philippe Couillard
- Department of Critical Care Medicine, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.,Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Andreas Kramer
- Department of Critical Care Medicine, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.,Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Brent W Winston
- Department of Critical Care Medicine, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.,Departments of Medicine and Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
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17
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Microglia are an essential component of the neuroprotective scar that forms after spinal cord injury. Nat Commun 2019; 10:518. [PMID: 30705270 PMCID: PMC6355913 DOI: 10.1038/s41467-019-08446-0] [Citation(s) in RCA: 348] [Impact Index Per Article: 69.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 01/08/2019] [Indexed: 12/19/2022] Open
Abstract
The role of microglia in spinal cord injury (SCI) remains poorly understood and is often confused with the response of macrophages. Here, we use specific transgenic mouse lines and depleting agents to understand the response of microglia after SCI. We find that microglia are highly dynamic and proliferate extensively during the first two weeks, accumulating around the lesion. There, activated microglia position themselves at the interface between infiltrating leukocytes and astrocytes, which proliferate and form a scar in response to microglia-derived factors, such as IGF-1. Depletion of microglia after SCI causes disruption of glial scar formation, enhances parenchymal immune infiltrates, reduces neuronal and oligodendrocyte survival, and impairs locomotor recovery. Conversely, increased microglial proliferation, induced by local M-CSF delivery, reduces lesion size and enhances functional recovery. Altogether, our results identify microglia as a key cellular component of the scar that develops after SCI to protect neural tissue. The role of microglia following spinal cord injury is not fully understood. Here, using transgenic approaches to selectively label microglia and not macrophages in mice, the authors show that microglia are highly active and accumulate at the edge of the lesion in the first weeks post injury, and also that inhibiting microglia activation impairs recovery in the early stages after spinal cord injury.
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18
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To Be or Not to Be: Environmental Factors that Drive Myelin Formation during Development and after CNS Trauma. ACTA ACUST UNITED AC 2018. [DOI: 10.3390/neuroglia1010007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Oligodendrocytes are specialized glial cells that myelinate central nervous system (CNS) axons. Historically, it was believed that the primary role of myelin was to compactly ensheath axons, providing the insulation necessary for rapid signal conduction. However, mounting evidence demonstrates the dynamic importance of myelin and oligodendrocytes, including providing metabolic support to neurons and regulating axon protein distribution. As such, the development and maintenance of oligodendrocytes and myelin are integral to preserving CNS homeostasis and supporting proper functioning of widespread neural networks. Environmental signals are critical for proper oligodendrocyte lineage cell progression and their capacity to form functional compact myelin; these signals are markedly disturbed by injury to the CNS, which may compromise endogenous myelin repair capabilities. This review outlines some key environmental factors that drive myelin formation during development and compares that to the primary factors that define a CNS injury milieu. We aim to identify developmental factors disrupted after CNS trauma as well as pathogenic factors that negatively impact oligodendrocyte lineage cells, as these are potential therapeutic targets to promote myelin repair after injury or disease.
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19
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Ham TR, Leipzig ND. Biomaterial strategies for limiting the impact of secondary events following spinal cord injury. Biomed Mater 2018; 13:024105. [PMID: 29155409 PMCID: PMC5824690 DOI: 10.1088/1748-605x/aa9bbb] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The nature of traumatic spinal cord injury (SCI) often involves limited recovery and long-term quality of life complications. The initial injury sets off a variety of secondary cascades, which result in an expanded lesion area. Ultimately, the native tissue fails to regenerate. As treatments are developed in the laboratory, the management of this secondary cascade is an important first step in achieving recovery of normal function. Current literature identifies four broad targets for intervention: inflammation, oxidative stress, disruption of the blood-spinal cord barrier, and formation of an inhibitory glial scar. Because of the complex and interconnected nature of these events, strategies that combine multiple therapies together show much promise. Specifically, approaches that rely on biomaterials to perform a variety of functions are generating intense research interest. In this review, we examine each target and discuss how biomaterials are currently used to address them. Overall, we show that there are an impressive amount of biomaterials and combinatorial treatments which show good promise for slowing secondary events and improving outcomes. If more emphasis is placed on growing our understanding of how materials can manage secondary events, treatments for SCI can be designed in an increasingly rational manner, ultimately improving their potential for translation to the clinic.
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Affiliation(s)
- Trevor R Ham
- Department of Biomedical Engineering, Auburn Science and Engineering Center 275, West Tower, University of Akron, Akron, OH 44325-3908, United States of America
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20
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Ferbert T, Child C, Graeser V, Swing T, Akbar M, Heller R, Biglari B, Moghaddam A. Tracking Spinal Cord Injury: Differences in Cytokine Expression of IGF-1, TGF- B1, and sCD95l Can Be Measured in Blood Samples and Correspond to Neurological Remission in a 12-Week Follow-Up. J Neurotrauma 2017; 34:607-614. [DOI: 10.1089/neu.2015.4294] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Thomas Ferbert
- HTRG-Heidelberg Trauma Research Group, Trauma and Reconstructive Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany
| | - Christopher Child
- HTRG-Heidelberg Trauma Research Group, Trauma and Reconstructive Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany
| | - Viola Graeser
- HTRG-Heidelberg Trauma Research Group, Trauma and Reconstructive Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany
| | - Tyler Swing
- HTRG-Heidelberg Trauma Research Group, Trauma and Reconstructive Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany
| | - Michael Akbar
- HTRG-Heidelberg Trauma Research Group, Trauma and Reconstructive Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany
| | - Raban Heller
- HTRG-Heidelberg Trauma Research Group, Trauma and Reconstructive Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany
| | - Bahram Biglari
- Berufsgenossenschaftliche Unfallklinik Ludwigshafen, Department of Paraplegiology, Ludwigshafen, Germany
| | - Arash Moghaddam
- HTRG-Heidelberg Trauma Research Group, Trauma and Reconstructive Surgery, Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, Heidelberg University Hospital, Heidelberg, Germany
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21
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Yang Y, Guo C, Liao B, Cao J, Liang C, He X. BAMBI inhibits inflammation through the activation of autophagy in experimental spinal cord injury. Int J Mol Med 2016; 39:423-429. [PMID: 28035406 DOI: 10.3892/ijmm.2016.2838] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 12/14/2016] [Indexed: 11/06/2022] Open
Abstract
Autophagy plays an important role in the progression of spinal cord injury (SCI). In this study, we aimed to examine the effects and potential mechanisms of action of BMP and activin membrane-bound inhibitor (BAMBI) in the progression of SCI. A rat model of SCI was established and the rats were injected with pLentiH1-BAMBI shRNA and pAd-BAMBI in the gray and white matter of the spinal cord at T8. After 14 days, motor function evaluation was measured according to the Basso Beattie Bresnahan (BBB) method and the number of motor neuron cell accounts in the anterior horns was measured by Nissl staining. The protein expression of levels light chain 3B (LC3B), Beclin 1, Bim and p62 were measured by western blot analysis. The concentrations of interleukin (IL)-1β, IL-6 and IL-10 were measured by ELISA. The results revealed that BAMBI expression was significantly decreased in the rats with SCI. The BBB scores and the number of motor neuron cell accounts in the anterior horns were significantly decreased in the pLentiH1-BAMBI shRNA injection group, and were increased in the pAd-BAMBI injection group, suggesting a neuroprotective effect of BAMBI in SCI. Moreover, the increased expression levels of LC3B and Beclin 1, and the decreased expression of Bim and p62 indicated that autophagy was significantly induced in the pAd-BAMBI injection group. Moreover, the overexpression of BAMBI also decreased the expression of transforming growth factor-β (TGF-β) and mammalian target of rapamycin (mTOR), and decreased the concentrations of IL-1β, IL-6 and IL-10. These results indicate that BAMBI plays a neuroprotective role by decreasing inflammation and activating autophagy in rats with SCI.
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Affiliation(s)
- Yin Yang
- Department of Orthopaedics, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Chunyang Guo
- The Second Department of Orthopedics, Xi'an Central Hospital, Xi'an, Shaanxi 710003, P.R. China
| | - Bo Liao
- Department of Orthopaedics, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, P.R. China
| | - Junjun Cao
- The Second Department of Orthopedics, Xi'an Central Hospital, Xi'an, Shaanxi 710003, P.R. China
| | - Chen Liang
- The Second Department of Orthopedics, Xi'an Central Hospital, Xi'an, Shaanxi 710003, P.R. China
| | - Xijing He
- Department of Orthopaedics, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
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22
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Li S, Gu X, Yi S. The Regulatory Effects of Transforming Growth Factor-β on Nerve Regeneration. Cell Transplant 2016; 26:381-394. [PMID: 27983926 DOI: 10.3727/096368916x693824] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Transforming growth factor-β (TGF-β) belongs to a group of pleiotropic cytokines that are involved in a variety of biological processes, such as inflammation and immune reactions, cellular phenotype transition, extracellular matrix (ECM) deposition, and epithelial-mesenchymal transition. TGF-β is widely distributed throughout the body, including the nervous system. Following injury to the nervous system, TGF-β regulates the behavior of neurons and glial cells and thus mediates the regenerative process. In the current article, we reviewed the production, activation, as well as the signaling pathway of TGF-β. We also described altered expression patterns of TGF-β in the nervous system after nerve injury and the regulatory effects of TGF-β on nerve repair and regeneration in many aspects, including inflammation and immune response, phenotypic modulation of neural cells, neurite outgrowth, scar formation, and modulation of neurotrophic factors. The diverse biological actions of TGF-β suggest that it may become a potential therapeutic target for the treatment of nerve injury and regeneration.
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23
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Filous AR, Silver J. "Targeting astrocytes in CNS injury and disease: A translational research approach". Prog Neurobiol 2016; 144:173-87. [PMID: 27026202 PMCID: PMC5035184 DOI: 10.1016/j.pneurobio.2016.03.009] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 02/03/2016] [Accepted: 03/03/2016] [Indexed: 12/31/2022]
Abstract
Astrocytes are a major constituent of the central nervous system. These glia play a major role in regulating blood-brain barrier function, the formation and maintenance of synapses, glutamate uptake, and trophic support for surrounding neurons and glia. Therefore, maintaining the proper functioning of these cells is crucial to survival. Astrocyte defects are associated with a wide variety of neuropathological insults, ranging from neurodegenerative diseases to gliomas. Additionally, injury to the CNS causes drastic changes to astrocytes, often leading to a phenomenon known as reactive astrogliosis. This process is important for protecting the surrounding healthy tissue from the spread of injury, while it also inhibits axonal regeneration and plasticity. Here, we discuss the important roles of astrocytes after injury and in disease, as well as potential therapeutic approaches to restore proper astrocyte functioning.
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Affiliation(s)
- Angela R Filous
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 216-368-4615, United States.
| | - Jerry Silver
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 216-368-4615, United States.
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24
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Pharmacological Suppression of CNS Scarring by Deferoxamine Reduces Lesion Volume and Increases Regeneration in an In Vitro Model for Astroglial-Fibrotic Scarring and in Rat Spinal Cord Injury In Vivo. PLoS One 2015. [PMID: 26222542 PMCID: PMC4519270 DOI: 10.1371/journal.pone.0134371] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Lesion-induced scarring is a major impediment for regeneration of injured axons in the central nervous system (CNS). The collagen-rich glial-fibrous scar contains numerous axon growth inhibitory factors forming a regeneration-barrier for axons. We demonstrated previously that the combination of the iron chelator 2,2’-bipyridine-5,5’-decarboxylic acid (BPY-DCA) and 8-Br-cyclic AMP (cAMP) inhibits scar formation and collagen deposition, leading to enhanced axon regeneration and partial functional recovery after spinal cord injury. While BPY-DCA is not a clinical drug, the clinically approved iron chelator deferoxamine mesylate (DFO) may be a suitable alternative for anti-scarring treatment (AST). In order to prove the scar-suppressing efficacy of DFO we modified a recently published in vitro model for CNS scarring. The model comprises a co-culture system of cerebral astrocytes and meningeal fibroblasts, which form scar-like clusters when stimulated with transforming growth factor-β (TGF-β). We studied the mechanisms of TGF-β-induced CNS scarring and compared the efficiency of different putative pharmacological scar-reducing treatments, including BPY-DCA, DFO and cAMP as well as combinations thereof. We observed modulation of TGF-β-induced scarring at the level of fibroblast proliferation and contraction as well as specific changes in the expression of extracellular matrix molecules and axon growth inhibitory proteins. The individual and combinatorial pharmacological treatments had distinct effects on the cellular and molecular aspects of in vitro scarring. DFO could be identified as a putative anti-scarring treatment for CNS trauma. We subsequently validated this by local application of DFO to a dorsal hemisection in the rat thoracic spinal cord. DFO treatment led to significant reduction of scarring, slightly increased regeneration of corticospinal tract as well as ascending CGRP-positive axons and moderately improved locomotion. We conclude that the in vitro model for CNS scarring is suitable for efficient pre-screening and identification of putative scar-suppressing agents prior to in vivo application and validation, thus saving costs, time and laboratory animals.
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25
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Chen WF, Chen CH, Chen NF, Sung CS, Wen ZH. Neuroprotective Effects of Direct Intrathecal Administration of Granulocyte Colony-Stimulating Factor in Rats with Spinal Cord Injury. CNS Neurosci Ther 2015; 21:698-707. [PMID: 26190345 DOI: 10.1111/cns.12429] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 06/02/2015] [Accepted: 06/03/2015] [Indexed: 01/11/2023] Open
Abstract
AIMS To date, no reliable methods have proven effective for treating spinal cord injury (SCI). Even systemic administration of methylprednisolone (MP) remains controversial. We previously reported that intrathecal (i.t.) administration of granulocyte colony-stimulating factor (G-CSF) improves outcome after experimental spinal cord ischemic insults in rats. The present study aimed to examine the neuroprotective efficacy of i.t. G-CSF or MP in rats with SCI. METHODS Female rats were subjected to spinal cord contusion injury at T10 using NYU impactor. We i.t. administered G-CSF (10 μg) or MP (one bolus of 100 μg, followed by 18 μg/h infusion for 23 h) immediately after SCI. RESULTS Both G-CSF and MP significantly improved the rats' motor function after SCI. Immunofluorescence staining revealed suppressed expression of transforming growth factor-beta 1 (TGF-β1), chondroitin sulfate proteoglycans (neurocan and phosphacan), OX-42 and tumor necrosis factor alpha after i.t. G-CSF, but not MP, in rats with SCI. In addition, G-CSF significantly decreased the expression of astrocytic TGF-β1 and glial fibrillary acidic protein around the injury site. Furthermore, rats with G-CSF treatment showed increased neurofilament expression beyond the glial scars. CONCLUSION Direct i.t. administration of G-CSF provides a promising therapeutic option for SCI or related spinal diseases.
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Affiliation(s)
- Wu-Fu Chen
- Department of Neurosurgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.,Department of Neurosurgery, Xiamen Chang Gung Memorial Hospital, Xiamen, China.,Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Chun-Hong Chen
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University and Academia Sinica, Kaohsiung, Taiwan
| | - Nan-Fu Chen
- Division of Neurosurgery, Department of Surgery, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan
| | - Chun-Sung Sung
- Department of Anesthesiology, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Zhi-Hong Wen
- Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, Taiwan.,Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University and Academia Sinica, Kaohsiung, Taiwan
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26
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Haan N, Zhu B, Wang J, Wei X, Song B. Crosstalk between macrophages and astrocytes affects proliferation, reactive phenotype and inflammatory response, suggesting a role during reactive gliosis following spinal cord injury. J Neuroinflammation 2015; 12:109. [PMID: 26025034 PMCID: PMC4457974 DOI: 10.1186/s12974-015-0327-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 05/20/2015] [Indexed: 02/01/2023] Open
Abstract
Background Large-scale macrophage infiltration and reactive astrogliosis are hallmarks of early spinal cord injury (SCI) pathology. The exact nature of the macrophage response and relationship between these phenomena have not been explored in detail. Here, we have investigated these responses using a combination of in vivo SCI models, organotypic and primary cultures. Methods In vivo macrophage response was investigated using a contusive injury mouse model. Interactions between astrocytes and macrophages were studied in primary or organotypic cultures. Proliferation was assessed though MTT assay and nucleotide incorporation and gene expression changes through qPCR. Results Seven days following contusive SCI, a mixed M1/M2 macrophage response was seen in the injury site. Conditioned medium from primary M1, but not M2, macrophages are able to induce astrocyte proliferation in both organotypic spinal cord cultures and primary astrocytes. Soluble factors from M1 macrophages induce a reactive astrocyte gene expression pattern, whereas M2 factors inhibit expression of these genes. M2-stimulated astrocytes are also able to decrease both M1 and M2 macrophage proliferation and decrease TNFα production in M1 macrophages. Conclusions These results suggest a strong role of M1 macrophages in inducing reactive astrogliosis and the existence of an astrocyte-mediated negative feedback system in order to dampen the immune response. These results, combined with the poor outcomes of the current immunosuppressive steroid treatments in SCI, indicate the need for more targeted therapies, taking into account the significantly different effects of M1 and M2 macrophages, in order to optimise outcome. Electronic supplementary material The online version of this article (doi:10.1186/s12974-015-0327-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Niels Haan
- Cardiff Institute of Tissue Engineering & Repair, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Heath Campus, Cardiff, CF14 4XY, UK. .,Neuroscience and Mental Health Research Institute, College of Biomedical and Life Sciences, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK.
| | - Bangfu Zhu
- Cardiff Institute of Tissue Engineering & Repair, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Heath Campus, Cardiff, CF14 4XY, UK.
| | - Jian Wang
- Institute of Neurosciences, Fourth Military Medical University, 169 West Changle Road, Xi'an, 710032, China.
| | - Xiaoqing Wei
- Cardiff Institute of Tissue Engineering & Repair, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Heath Campus, Cardiff, CF14 4XY, UK.
| | - Bing Song
- Cardiff Institute of Tissue Engineering & Repair, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Heath Campus, Cardiff, CF14 4XY, UK. .,Department of Dermatology, No. 1 Hospital of China Medical University, Shenyang, 110001, China.
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Leibig N, Boyle V, Kraus D, Stark GB, Penna V. Il10 and poly-dl
-lactide-ɛ-caprolactone conduits in critical size nerve defect bridging-An experimental study. Microsurgery 2015; 36:410-416. [DOI: 10.1002/micr.22423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 04/07/2015] [Accepted: 04/10/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Nico Leibig
- Department of Hand; Plastic and Reconstructive Surgery, BG Trauma Centre; Ludwigshafen Germany
| | - Veronika Boyle
- Clinic for Neurology, Ortenau Klinikum Lahr-Ettenheim; Lahr Germany
| | - Daniel Kraus
- Clinic of Plastic and Hand Surgery, University Medical Center; Freiburg Germany
| | | | - Vincenzo Penna
- Clinic of Plastic and Hand Surgery, University Medical Center; Freiburg Germany
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Xu H, Liu C, Sun Z, Guo X, Zhang Y, Liu M, Li P. CCN5 attenuates profibrotic phenotypes of fibroblasts through the Smad6-CCN2 pathway: Potential role in epidural fibrosis. Int J Mol Med 2015; 36:123-9. [PMID: 25901787 PMCID: PMC4494601 DOI: 10.3892/ijmm.2015.2190] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 03/27/2015] [Indexed: 12/31/2022] Open
Abstract
Epidural fibrosis is characterized by the development of dense and thick scar tissue adjacent to the dural mater and ranked as the major contributor for post-operative pain recurrence after laminectomy or discectomy. Recently, CCN5 exhibited an inhibitory effect on connective tissue growth factor (CTGF)/CCN2 (a critical regulator for fibrotic disease)-mediated fibrogenesis. However, its function in epidural fibrosis and the underlying mechanisms involved remain to be determined. In this study, an obvious downregulation of CCN5 was observed in scar tissues from laminectomized rats, concomitant with a marked upregulation of CCN2, suggesting a potential negative regulatory role of CCN5 in fibrogenesis. Furthermore, CCN5 overexpression notably mitigated transforming growth factor-β1-enhanced fibroblast viability and proliferation. Of note, CCN5 upregulation inhibited the switch of fibroblasts into myofibroblasts as its overexpression abrogated the expression of the myofibroblast marker, α-smooth muscle actin (α-SMA). CCN5 upregulation also reduced an increase in collagen type I, α1 (COL1A1) and total collagen concentrations. Additionally, CCN5 over expression decreased CCN2 expression and increased Smad6 phosphorylation. Mechanism analysis revealed that blocking Smad6 signaling significantly ameliorated the inhibitory effect of CCN5 on the CCN2 levels, accompanied by the reduction in cell proliferation and collagen production. These results confirm that CCN5 exerts an anti-fibrotic function by regulating the Smad6-CCN2 pathway, thereby indicating a potential approach for ameliorating epidural fibrosis after laminectomy.
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Affiliation(s)
- Honghai Xu
- Department of Orthopaedics, The Third Affiliated Hospital (Shaanxi Provincial People's Hospital), Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Cong Liu
- Xi'an Medical College, Xi'an, Shaanxi 710061, P.R. China
| | - Zhengming Sun
- Department of Orthopaedics, The Third Affiliated Hospital (Shaanxi Provincial People's Hospital), Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Xiong Guo
- Department of Public Health, Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Yuelin Zhang
- Department of Neurosurgery, The Third Affiliated Hospital (Shaanxi Provincial People's Hospital), Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Mengting Liu
- Xi'an Medical College, Xi'an, Shaanxi 710061, P.R. China
| | - Peng Li
- Xi'an Medical College, Xi'an, Shaanxi 710061, P.R. China
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29
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Yuan J, Zou M, Xiang X, Zhu H, Chu W, Liu W, Chen F, Lin J. Curcumin improves neural function after spinal cord injury by the joint inhibition of the intracellular and extracellular components of glial scar. J Surg Res 2015; 195:235-45. [PMID: 25661742 DOI: 10.1016/j.jss.2014.12.055] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 12/10/2014] [Accepted: 12/31/2014] [Indexed: 12/21/2022]
Abstract
BACKGROUND Spinal cord injury (SCI) is characterized by a high rate of disability and imposes a heavy burden on society and patients. SCI can activate glial cells and lead to swelling, hyperplasty, and reactive gliosis, which can severely reduce the space for nerve growth. Glial cells can secrete a large amount of extracellular inhibitory components, thus altering the microenvironment of axon growth. Both these factors seriously impede nerve regeneration. In the present study, we investigate whether curcumin (cur), a phytochemical compound with potent anti-inflammatory effect, plays a role in the repair of SCI. MATERIALS AND METHODS We established a rat model of SCI and treated the animals with different concentrations of cur. Using behavioral assessment, immunohistochemistry, real-time polymerase chain reaction, Western blotting, and enzyme-linked immunosorbent assay, we detected the intracellular and extracellular components of glial scar and related cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, nuclear factor (NF)-κb, transforming growth factor (TGF)-β1, TGF-β2, and sex determining region Y-box (SOX)-9. RESULTS We found that cur inhibited the expression of proinflammatory cytokines, such as TNF-α, IL-1β, and NF-κb; reduced the expression of the intracellular components glial fibrillary acidic protein through anti-inflammation; and suppressed the reactive gliosis. Also, cur inhibited the generation of TGF-β1, TGF-β2, and SOX-9; decreased the deposition of chondroitin sulfate proteoglycan by inhibiting the transforming growth factors and transcription factor; and improved the microenvironment for nerve growth. Through the joint inhibition of the intracellular and extracellular components of glial scar, cur significantly reduced glial scar volume and improved the Basso, Beattie, and Bresnahan locomotor rating and axon growth. CONCLUSIONS Our data support a role for curcumin in promoting neural function recovery after SCI by the joint inhibition of the intracellular and extracellular components of glial scar, providing an important strategy for treating SCI.
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Affiliation(s)
- Jichao Yuan
- Department of Neurosurgery, Institute of Neurosurgery, Key Laboratory of Neurotrauma Prevention and Treatment, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Mingming Zou
- Affiliated Bayi Brain Hospital, General Hospital of Beijing Military Region, Beijing, China
| | - Xin Xiang
- Department of Neurosurgery, Institute of Neurosurgery, Key Laboratory of Neurotrauma Prevention and Treatment, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Haitao Zhu
- Department of Neurosurgery, Institute of Neurosurgery, Key Laboratory of Neurotrauma Prevention and Treatment, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Weihua Chu
- Department of Neurosurgery, Institute of Neurosurgery, Key Laboratory of Neurotrauma Prevention and Treatment, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Wei Liu
- Department of Neurosurgery, Institute of Neurosurgery, Key Laboratory of Neurotrauma Prevention and Treatment, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Fei Chen
- Department of Neurosurgery, Institute of Neurosurgery, Key Laboratory of Neurotrauma Prevention and Treatment, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Jiangkai Lin
- Department of Neurosurgery, Institute of Neurosurgery, Key Laboratory of Neurotrauma Prevention and Treatment, Southwest Hospital, Third Military Medical University, Chongqing, China.
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30
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Bastien D, Lacroix S. Cytokine pathways regulating glial and leukocyte function after spinal cord and peripheral nerve injury. Exp Neurol 2014; 258:62-77. [PMID: 25017888 DOI: 10.1016/j.expneurol.2014.04.006] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 02/20/2014] [Accepted: 04/08/2014] [Indexed: 01/13/2023]
Abstract
Injury to the nervous system causes the almost immediate release of cytokines by glial cells and neurons. These cytokines orchestrate a complex array of responses leading to microgliosis, immune cell recruitment, astrogliosis, scarring, and the clearance of cellular debris, all steps that affect neuronal survival and repair. This review will focus on cytokines released after spinal cord and peripheral nerve injury and the primary signalling pathways triggered by these inflammatory mediators. Notably, the following cytokine families will be covered: IL-1, TNF, IL-6-like, TGF-β, and IL-10. Whether interfering with cytokine signalling could lead to novel therapies will also be discussed. Finally, the review will address whether manipulating the above-mentioned cytokine families and signalling pathways could exert distinct effects in the injured spinal cord versus peripheral nerve.
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Affiliation(s)
- Dominic Bastien
- Centre de recherche du Centre hospitalier universitaire de Québec-CHUL, Département de médecine moléculaire, Université Laval, Québec, QC, Canada
| | - Steve Lacroix
- Centre de recherche du Centre hospitalier universitaire de Québec-CHUL, Département de médecine moléculaire, Université Laval, Québec, QC, Canada..
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Hanada M, Tsutsumi K, Arima H, Shinjo R, Sugiura Y, Imagama S, Ishiguro N, Matsuyama Y. Evaluation of the effect of tranilast on rats with spinal cord injury. J Neurol Sci 2014; 346:209-15. [PMID: 25194634 DOI: 10.1016/j.jns.2014.08.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/17/2014] [Accepted: 08/20/2014] [Indexed: 01/30/2023]
Abstract
BACKGROUND Glial and fibrotic scars inhibit neural regeneration after spinal cord injury (SCI). N-[3,4-dimethoxycinnamoyl]-anthranilic acid (tranilast) inhibits transforming growth factor β, alleviates allergic reactions, and decreases hypertrophic skin scars. We evaluated its ability to improve motor function and inhibit the spread of tissue damage in rats with SCI. METHODS Rats with SCI were divided into groups that received tranilast (30 mg/[kg · day]) by intravenous administration (group IV), tranilast (200mg/[kg · day]) by oral administration (group OR), and saline injections (control). Motor functions were assessed by determining Basso, Beattie, and Bresnahan (BBB) scores and %grip tests for 8 weeks after SCI. Histological evaluation of ionized calcium binding adaptor molecule 1 (Iba1) at 1 week after SCI and glial fibrillary acidic protein (GFAP), fibronectin, and chondroitin sulfate (CS) at week 8 was performed. RESULTS Motor function recovery, BBB score, and the %grip test were significantly higher in the tranilast-treated groups than in the control group. At week 1 after SCI, inflammatory-cell invasion was more severe and Iba1 expression was significantly higher in the control group. At week 8, although the number of GFAP-positive cells increased greatly from the impaction site to the proximal and distal sites in the control group, these cells were confined around a cavity in the tranilast-treated groups. GFAP distribution coincided with that of fibronectin. Anti-CS antibody level in the tranilast-treated groups was significantly lower than that in the control group. CONCLUSIONS Tranilast inhibits inflammation in the acute phase of SCI and reduces glial and fibrotic scars and could present a new method for treating SCI.
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Affiliation(s)
- Mitsuru Hanada
- Department of Orthopaedic Surgery, Hamamatsu University School of Medicine, Handayama 1-20-1, Hamamatsu, Shizuoka 431-3192, Japan.
| | - Koji Tsutsumi
- Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan
| | - Hideyuki Arima
- Department of Orthopaedic Surgery, Hamamatsu University School of Medicine, Handayama 1-20-1, Hamamatsu, Shizuoka 431-3192, Japan
| | - Ryuichi Shinjo
- Department of Orthopedics, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Yuki Sugiura
- Department of Biochemistry, Keio University School of Medicine, Tokyo 160-8582, Japan; JST Precursory Research for Embryonic Science and Technology (PRESTO) Project, Japan
| | - Shiro Imagama
- Department of Orthopedics, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Naoki Ishiguro
- Department of Orthopedics, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Yukihiro Matsuyama
- Department of Orthopaedic Surgery, Hamamatsu University School of Medicine, Handayama 1-20-1, Hamamatsu, Shizuoka 431-3192, Japan.
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Scar-modulating treatments for central nervous system injury. Neurosci Bull 2014; 30:967-984. [PMID: 24957881 DOI: 10.1007/s12264-013-1456-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 04/09/2014] [Indexed: 02/04/2023] Open
Abstract
Traumatic injury to the adult mammalian central nervous system (CNS) leads to complex cellular responses. Among them, the scar tissue formed is generally recognized as a major obstacle to CNS repair, both by the production of inhibitory molecules and by the physical impedance of axon regrowth. Therefore, scar-modulating treatments have become a leading therapeutic intervention for CNS injury. To date, a variety of biological and pharmaceutical treatments, targeting scar modulation, have been tested in animal models of CNS injury, and a few are likely to enter clinical trials. In this review, we summarize current knowledge of the scar-modulating treatments according to their specific aims: (1) inhibition of glial and fibrotic scar formation, and (2) blockade of the production of scar-associated inhibitory molecules. The removal of existing scar tissue is also discussed as a treatment of choice. It is believed that only a combinatorial strategy is likely to help eliminate the detrimental effects of scar tissue on CNS repair.
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Differential cavitation, angiogenesis and wound-healing responses in injured mouse and rat spinal cords. Neuroscience 2014; 275:62-80. [PMID: 24929066 DOI: 10.1016/j.neuroscience.2014.06.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 05/21/2014] [Accepted: 06/04/2014] [Indexed: 11/23/2022]
Abstract
The vascular disruption, blood vessel loss and cavitation that occur at spinal cord injury (SCI) epicenters in mice and rats are different, but few studies have compared the acute SCI response in the two species. This is of interest since key elements of the rat SCI response are shared with humans. In this study, we investigated acute SCI responses and characterized changes in pro- and anti-angiogenic factors and matrix deposition in both species. Cavitation was absent in mouse but the area of the lesion site was 21- and 27-fold larger at 8 and 15 days post-lesion (dpl), respectively, in the rat compared to intact control. The absence of wound cavitation in the mouse was correlated with increased levels of immunoreactive pro-angiogenic, pro-matrix and pro-wound-healing factors, e.g. laminin, matrix metalloproteinase-1 (MMP-1) and vascular endothelial growth factor-A (VEGF-A) within the wound, which were 6.0-, 2.9-, and 2.8-fold, respectively, higher in the mouse compared to rats at 8 dpl. Increased axonal sparing was observed after dorsal column (DC) injury, detected by higher levels of neurofilament 200 (NF200) immunoreactivity in the dorsal column of mice compared to rats at both T7 and T9 spinal segments. Despite similar post SCI deficits in plantar heat tests at 2h after injury (1.4- and 1.6-fold lower than control mice and rats, respectively), by 7 days the magnitude of these responses were comparable to sham-treated controls in both species, while no post-SCI changes in Von Frey hair filament test response were observed in either species. We conclude that the more robust angiogenesis/wound-healing response in the mouse attenuates post-injury wound cavitation. Although the spinal cord functions that were monitored post-injury were similarly affected in both species, we suggest that the quality of the angiogenesis/wound-healing response together with the diminished lesion size seen after mouse SCI may protect against secondary axon damage and create an environment more conducive to axon sprouting/regeneration. These results suggest the potential therapeutic utility of manipulating the angiogenic response after human SCI.
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Yuan YM, He C. The glial scar in spinal cord injury and repair. Neurosci Bull 2013; 29:421-35. [PMID: 23861090 DOI: 10.1007/s12264-013-1358-3] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 05/03/2013] [Indexed: 12/21/2022] Open
Abstract
Glial scarring following severe tissue damage and inflammation after spinal cord injury (SCI) is due to an extreme, uncontrolled form of reactive astrogliosis that typically occurs around the injury site. The scarring process includes the misalignment of activated astrocytes and the deposition of inhibitory chondroitin sulfate proteoglycans. Here, we first discuss recent developments in the molecular and cellular features of glial scar formation, with special focus on the potential cellular origin of scar-forming cells and the molecular mechanisms underlying glial scar formation after SCI. Second, we discuss the role of glial scar formation in the regulation of axonal regeneration and the cascades of neuro-inflammation. Last, we summarize the physical and pharmacological approaches targeting the modulation of glial scarring to better understand the role of glial scar formation in the repair of SCI.
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Affiliation(s)
- Yi-Min Yuan
- Institute of Neuroscience and Key Laboratory of Molecular Neurobiology of Ministry of Education, Neuroscience Research Center of Changzheng Hospital, Second Military Medical University, Shanghai 200433, China
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Joko M, Osuka K, Usuda N, Atsuzawa K, Aoyama M, Takayasu M. Different modifications of phosphorylated Smad3C and Smad3L through TGF-β after spinal cord injury in mice. Neurosci Lett 2013; 549:168-72. [PMID: 23727390 DOI: 10.1016/j.neulet.2013.05.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 05/20/2013] [Accepted: 05/21/2013] [Indexed: 10/26/2022]
Abstract
Transforming growth factor-β (TGF-β) is an anti-inflammatory cytokine and is expressed in the injured spinal cord. TGF-β signals through receptors to activate Smad proteins, which translocate into the nucleus. In the present study, we investigated the chronological alterations and cellular locations of the TGF-β/Smad signaling pathway following spinal cord injury (SCI) in mice. ELISA analysis showed that the concentration of interleukin-6 (IL-6) in injured spinal cords significantly increases immediately after SCI, while the concentration of TGF-β gradually increased after SCI, peaked at 2 days, and then gradually decreased. Immunohistochemical studies revealed that Smad3 was mainly expressed in neurons of the spinal cord. Phosphorylated Smad3 at the C-terminus (p-Smad3C) was stained within the motor neurons in the anterior horn, while phosphorylated Smad3 at the linker regions (p-Smad3L) was expressed in astrocytes within gray matter. These findings suggest that SCI induces gradual increases in TGF-β and induces different activation of p-Smad3C and p-Smad3L. Phosphorylated Smad3C might be involved in neuronal degeneration after SCI, and p-Smad3L may play a role in glial scar formation by astrocytes.
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Affiliation(s)
- Masahiro Joko
- Department of Neurological Surgery, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi 480-1195, Japan
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Kundi S, Bicknell R, Ahmed Z. The role of angiogenic and wound-healing factors after spinal cord injury in mammals. Neurosci Res 2013; 76:1-9. [PMID: 23562792 DOI: 10.1016/j.neures.2013.03.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/18/2013] [Accepted: 03/20/2013] [Indexed: 12/17/2022]
Abstract
Patients with spinal cord injury (SCI) are permanently paralysed and anaesthetic below the lesion. This morbidity is attributed to the deposition of a dense scar at the injury site, the cellular components of which secrete axon growth inhibitory ligands that prevent severed axons reconnecting with denervated targets. Another complication of SCI is wound cavitation where a fluid filled cyst forms in the peri-lesion neuropil, enlarging over the first few months after injury and causes secondary axonal damage. Wound healing after SCI is accompanied by angiogenesis, which is regulated by angiogenic proteins, produced in response to oxygen deprivation. Necrosis in and about the SCI lesion sites may be suppressed by promoting angiogenesis and the resulting neuropil protection will enhance recovery after SCI. This review addresses the use of angiogenic/wound-healing related proteins including vascular endothelial growth factor, fibroblast growth factor, angiopoietin-1, angiopoietin-2 and transforming growth factor-β to moderate necrosis and axon sparing after SCI, providing a conducive environment for growth essential to functional recovery.
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Affiliation(s)
- Sarina Kundi
- Neurotrauma and Neurodegeneration, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham B15 2TT, UK
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Vidal PM, Lemmens E, Dooley D, Hendrix S. The role of “anti-inflammatory” cytokines in axon regeneration. Cytokine Growth Factor Rev 2013; 24:1-12. [DOI: 10.1016/j.cytogfr.2012.08.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 08/20/2012] [Indexed: 11/25/2022]
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Huang XQ, Zhang XY, Wang XR, Yu SY, Fang SH, Lu YB, Zhang WP, Wei EQ. Transforming growth factor β1-induced astrocyte migration is mediated in part by activating 5-lipoxygenase and cysteinyl leukotriene receptor 1. J Neuroinflammation 2012; 9:145. [PMID: 22734808 PMCID: PMC3419068 DOI: 10.1186/1742-2094-9-145] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Accepted: 05/17/2012] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Transforming growth factor-β 1 (TGF-β 1) is an important regulator of cell migration and plays a role in the scarring response in injured brain. It is also reported that 5-lipoxygenase (5-LOX) and its products, cysteinyl leukotrienes (CysLTs, namely LTC₄, LTD₄ and LTE₄), as well as cysteinyl leukotriene receptor 1 (CysLT₁R) are closely associated with astrocyte proliferation and glial scar formation after brain injury. However, how these molecules act on astrocyte migration, an initial step of the scarring response, is unknown. To clarify this, we determined the roles of 5-LOX and CysLT₁R in TGF-β 1-induced astrocyte migration. METHODS In primary cultures of rat astrocytes, the effects of TGF-β 1 and CysLT receptor agonists on migration and proliferation were assayed, and the expression of 5-LOX, CysLT receptors and TGF-β1 was detected. 5-LOX activation was analyzed by measuring its products (CysLTs) and applying its inhibitor. The role of CysLT₁R was investigated by applying CysLT receptor antagonists and CysLT₁R knockdown by small interfering RNA (siRNA). TGF-β 1 release was assayed as well. RESULTS TGF-β 1-induced astrocyte migration was potentiated by LTD₄, but attenuated by the 5-LOX inhibitor zileuton and the CysLT₁R antagonist montelukast. The non-selective agonist LTD₄ at 0.1 to 10 nM also induced a mild migration; however, the selective agonist N-methyl-LTC₄ and the selective antagonist Bay cysLT2 for CysLT₂R had no effects. Moreover, CysLT₁R siRNA inhibited TGF-β 1- and LTD₄-induced astrocyte migration by down-regulating the expression of this receptor. However, TGF-β 1 and LTD4 at various concentrations did not affect astrocyte proliferation 24 h after exposure. On the other hand, TGF-β 1 increased 5-LOX expression and the production of CysLTs, and up-regulated CysLT1R (not CysLT₂R), while LTD4 and N-methyl-LTC4 did not affect TGF-β 1 expression and release. CONCLUSIONS TGF-β 1-induced astrocyte migration is, at least in part, mediated by enhanced endogenous CysLTs through activating CysLT₁R. These findings indicate that the interaction between the cytokine TGF-β 1 and the pro-inflammatory mediators CysLTs in the regulation of astrocyte function is relevant to glial scar formation.
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Affiliation(s)
- Xue-Qin Huang
- Department of Pharmacology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou 310058, China
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Lively S, Schlichter LC. Age-related comparisons of evolution of the inflammatory response after intracerebral hemorrhage in rats. Transl Stroke Res 2012; 3:132-46. [PMID: 22707991 PMCID: PMC3372776 DOI: 10.1007/s12975-012-0151-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 02/28/2012] [Accepted: 03/01/2012] [Indexed: 12/14/2022]
Abstract
In the hours to days after intracerebral hemorrhage (ICH), there is an inflammatory response within the brain characterized by the infiltration of peripheral neutrophils and macrophages and the activation of brain-resident microglia and astrocytes. Despite the strong correlation of aging and ICH incidence, and increasing information about cellular responses, little is known about the temporal- and age-related molecular responses of the brain after ICH. Here, we monitored a panel of 27 genes at 6 h and 1, 3, and 7 days after ICH was induced by injecting collagenase into the striatum of young adult and aged rats. Several molecules (CR3, TLR2, TLR4, IL-1β, TNFα, iNOS, IL-6) were selected to reflect the classical activation of innate immune cells (macrophages, microglia) and the potential to exacerbate inflammation and damage brain cells. Most of the others are associated with the resolution of innate inflammation, alternative pathways of macrophage/microglial activation, and the repair phase after acute injury (TGFβ, IL-1ra, IL-1r2, IL-4, IL-13, IL-4Rα, IL-13Rα1, IL-13Rα2, MRC1, ARG1, CD163, CCL22). In young animals, the up-regulation of 26 in 27 genes (not IL-4) was detected within the first week. Differences in timing or levels between young and aged animals were detected for 18 of 27 genes examined (TLR2, GFAP, IL-1β, IL-1ra, IL-1r2, iNOS, IL-6, TGFβ, MMP9, MMP12, IL-13, IL-4Rα, IL-13Rα1, IL-13Rα2, MRC1, ARG1, CD163, CCL22), with a generally less pronounced or delayed inflammatory response in the aged animals. Importantly, within this complex response to experimental ICH, the induction of pro-inflammatory, potentially harmful mediators often coincided with resolving and beneficial molecules.
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Sakalidou M, Leibig N, Boyle V, Koulaxouzidis G, Penna V. Interleukin-10 and regeneration in an end-to-side nerve repair model of the rat. J Peripher Nerv Syst 2011; 16:334-40. [DOI: 10.1111/j.1529-8027.2011.00368.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Beck K, Schachtrup C. Vascular damage in the central nervous system: a multifaceted role for vascular-derived TGF-β. Cell Tissue Res 2011; 347:187-201. [PMID: 21850492 DOI: 10.1007/s00441-011-1228-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 07/22/2011] [Indexed: 01/16/2023]
Abstract
The brain function depends on a continuous supply of blood. The blood-brain barrier (BBB), which is formed by vascular cells and glia, separates components of the circulating blood from neurons and maintains the precisely regulated brain milieu required for proper neuronal function. A compromised BBB alters the transport of molecules between the blood and brain and has been associated with or shown to precede neurodegenerative disease. Blood components immediately leak into the brain after mechanical damage or as a consequence of a compromised BBB in brain disease changing the extracellular environment at sites of vascular damage. It is intriguing how blood-derived components alter the cellular and molecular constituents of the neurovascular interface after BBB opening. We recently identified an unexpected role for the blood protein fibrinogen, which is deposited in the nervous system promptly after vascular damage, as an initial scar inducer by promoting the availability of active TGF-β. Fibrinogen-bound latent TGF-β interacts with astrocytes, leading to active TGF-β formation and activation of the TGF-β/Smad signaling pathway. Here, we discuss the pleiotropic effects of potentially vascular-derived TGF-β on cells at the neurovascular interface and we speculate how these biological effects might contribute to degeneration and regeneration processes. Summarizing the effects of the components derived from the brain vascular system on nervous system regeneration might support the development of new therapeutic approaches.
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Affiliation(s)
- Kristina Beck
- Centre of Chronic Immunodeficiency, University Medical Centre Freiburg and University of Freiburg, 79106 Freiburg, Germany
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Conversion of mechanical force into TGF-β-mediated biochemical signals. Curr Biol 2011; 21:933-41. [PMID: 21600772 PMCID: PMC3118584 DOI: 10.1016/j.cub.2011.04.007] [Citation(s) in RCA: 261] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Revised: 03/10/2011] [Accepted: 04/05/2011] [Indexed: 12/27/2022]
Abstract
Mechanical forces influence homeostasis in virtually every tissue [1, 2]. Tendon, constantly exposed to variable mechanical force, is an excellent model in which to study the conversion of mechanical stimuli into a biochemical response [3-5]. Here we show in a mouse model of acute tendon injury and in vitro that physical forces regulate the release of active transforming growth factor (TGF)-β from the extracellular matrix (ECM). The quantity of active TGF-β detected in tissue exposed to various levels of tensile loading correlates directly with the extent of physical forces. At physiological levels, mechanical forces maintain, through TGF-β/Smad2/3-mediated signaling, the expression of Scleraxis (Scx), a transcription factor specific for tenocytes and their progenitors. The gradual and temporary loss of tensile loading causes reversible loss of Scx expression, whereas sudden interruption, such as in transection tendon injury, destabilizes the structural organization of the ECM and leads to excessive release of active TGF-β and massive tenocyte death, which can be prevented by the TGF-β type I receptor inhibitor SD208. Our findings demonstrate a critical role for mechanical force in adult tendon homeostasis. Furthermore, this mechanism could translate physical force into biochemical signals in a much broader variety of tissues or systems in the body.
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Yu YM, Gibbs KM, Davila J, Campbell N, Sung S, Todorova TI, Otsuka S, Sabaawy HE, Hart RP, Schachner M. MicroRNA miR-133b is essential for functional recovery after spinal cord injury in adult zebrafish. Eur J Neurosci 2011; 33:1587-97. [PMID: 21447094 DOI: 10.1111/j.1460-9568.2011.07643.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
MicroRNAs (miRNAs) play important roles during development and also in adult organisms by regulating the expression of multiple target genes. Here, we studied the function of miR-133b during zebrafish spinal cord regeneration and show upregulation of miR-133b expression in regenerating neurons of the brainstem after transection of the spinal cord. miR-133b has been shown to promote tissue regeneration in other tissue, but its ability to do so in the nervous system has yet to be tested. Inhibition of miR-133b expression by antisense morpholino (MO) application resulted in impaired locomotor recovery and reduced regeneration of axons from neurons in the nucleus of the medial longitudinal fascicle, superior reticular formation and intermediate reticular formation. miR-133b targets the small GTPase RhoA, which is an inhibitor of axonal growth, as well as other neurite outgrowth-related molecules. Our results indicate that miR-133b is an important determinant in spinal cord regeneration of adult zebrafish through reduction in RhoA protein levels by direct interaction with its mRNA. While RhoA has been studied as a therapeutic target in spinal cord injury, this is the first demonstration of endogenous regulation of RhoA by a microRNA that is required for spinal cord regeneration in zebrafish. The ability of miR-133b to suppress molecules that inhibit axon regrowth may underlie the capacity for adult zebrafish to recover locomotor function after spinal cord injury.
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Affiliation(s)
- Young-Mi Yu
- W. M. Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
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Yoshioka N, Kimura-Kuroda J, Saito T, Kawamura K, Hisanaga SI, Kawano H. Small molecule inhibitor of type I transforming growth factor-β receptor kinase ameliorates the inhibitory milieu in injured brain and promotes regeneration of nigrostriatal dopaminergic axons. J Neurosci Res 2010; 89:381-93. [PMID: 21259325 DOI: 10.1002/jnr.22552] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 10/14/2010] [Accepted: 10/19/2010] [Indexed: 12/15/2022]
Abstract
Transforming growth factor-β (TGF-β), a multifunctional cytokine, plays a crucial role in wound healing in the damaged central nervous system. To examine effects of the TGF-β signaling inhibition on formation of scar tissue and axonal regeneration, the small molecule inhibitor of type I TGF-β receptor kinase LY-364947 was continuously infused in the lesion site of mouse brain after a unilateral transection of the nigrostriatal dopaminergic pathway. At 2 weeks after injury, the fibrotic scar comprising extracellular matrix molecules including fibronectin, type IV collagen, and chondroitin sulfate proteoglycans was formed in the lesion center, and reactive astrocytes were increased around the fibrotic scar. In the brain injured and infused with LY-364947, fibrotic scar formation was suppressed and decreased numbers of reactive astrocytes occupied the lesion site. Although leukocytes and serum IgG were observed within the fibrotic scar in the injured brain, they were almost absent in the injured and LY-364947-treated brain. At 2 weeks after injury, tyrosine hydroxylase (TH)-immunoreactive fibers barely extended beyond the fibrotic scar in the injured brain, but numerous TH-immunoreactive fibers regenerated over the lesion site in the LY-364947-treated brain. These results indicate that inhibition of TGF-β signaling suppresses formation of the fibrotic scar and creates a permissive environment for axonal regeneration.
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Affiliation(s)
- Nozomu Yoshioka
- Department of Developmental Morphology, Tokyo Metropolitan Institute for Neuroscience, Tokyo, Japan
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