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Chen G, Wang X, Jin Z, Hu G, Yu Q, Jiang H. HIF-1α knockdown attenuates inflammation and oxidative stress in ischemic stroke male rats via CXCR4/NF-κB pathway. Brain Behav 2024; 14:e70039. [PMID: 39295108 PMCID: PMC11410888 DOI: 10.1002/brb3.70039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 07/01/2024] [Accepted: 08/03/2024] [Indexed: 09/21/2024] Open
Abstract
BACKGROUND Hypoxia inducible factor-1α (HIF-1α) is a sensitive indicator of oxygen homeostasis, of which the expression elevates following hypoxia/ischemia. This study reveals the specific mechanisms underlying the effects of HIF-1α on ischemic stroke (IS). METHODS IS model was established using middle cerebral artery occlusion (MCAO)-modeled male rats and oxygen glucose deprivation/reoxygenation (OGD/R)-treated mice hippocampal cells HT22, followed by the silencing of HIF-1α and the overexpression of C-X-C motif chemokine receptor 4 (CXCR4) and nuclear factor-kappa B (NF-κB). Following the surgery, Garcia's grading scale was applied for neurological evaluation. Cerebral infarcts and injuries were visualized using 2,3,5-triphenyltetrazolium chloride and hematoxylin-eosin staining. The levels of tumor necrosis factor-α, Interleukin (IL)-6, IL-1β, malondialdehyde, and 8-hydroxy-2'-deoxyguanosine, were calculated via ELISA. MTT assay and lactate dehydrogenase (LDH) assay kit were adopted to determine the viability and cytotoxicity of OGD/R-modeled cells. Reactive oxygen species (ROS) generation was evaluated using a 2'-7'dichlorofluorescin diacetate (DCFH-DA) probe. The levels of HIF-1α, CXCR4, and NF-κB p65 were quantified via Western blot and immunofluorescence, respectively. RESULTS HIF-1α knockdown improved Garcia's score, attenuated the cerebral infarct, inflammation, and ROS generation, and alleviated the levels of inflammatory cytokines and CXCR4/NF-κB p65 in MCAO-modeled rats. Such effects were reversed following the overexpression of CXCR4 and NF-κB. Also, in OGD/R-treated HT22 cells, HIF-1α silencing diminished the cytotoxicity and ROS production and reduced the expressions of CXCR4/NF-κB p65, while promoting viability. However, CXCR4/NF-κB p65 overexpression did the opposite. CONCLUSION HIF-1α knockdown alleviates inflammation and oxidative stress in IS through the CXCR4/NF-κB pathway.
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Affiliation(s)
- Gao Chen
- School of MedicineQuzhou College of TechnologyQuzhouZhejiangChina
| | - Xi Wang
- Department of UrologyThe Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's HospitalQuzhouZhejiangChina
| | - Zhan Jin
- School of MedicineQuzhou College of TechnologyQuzhouZhejiangChina
| | - Gao‐Bo Hu
- School of MedicineQuzhou College of TechnologyQuzhouZhejiangChina
| | - Qi‐Hui Yu
- School of MedicineQuzhou College of TechnologyQuzhouZhejiangChina
| | - Hai‐Yan Jiang
- Department of GynecologyQuzhou Maternal and Child Health Care HospitalQuzhouZhejiangChina
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Song M, Yi F, Zeng F, Zheng L, Huang L, Sun X, Huang Q, Deng J, Wang H, Gu W. USP18 Stabilized FTO Protein to Activate Mitophagy in Ischemic Stroke Through Repressing m6A Modification of SIRT6. Mol Neurobiol 2024; 61:6658-6674. [PMID: 38340205 DOI: 10.1007/s12035-024-04001-1] [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: 10/16/2023] [Accepted: 01/28/2024] [Indexed: 02/12/2024]
Abstract
Ischemic stroke (IS) is a dangerous cerebrovascular disorder with a significant incidence and death rate. Ubiquitin-specific peptidase 18 (USP18) has been proven to mitigate ischemic brain damage; however, its potential regulatory mechanisms remain unclear. In vivo and in vitro models of IS were established by middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation/reoxygenation (OGD/R). Neurocyte injury was detected by MTT, LDH, ROS level, mitochondrial membrane potential (Δψm), and flow cytometry. Molecular expression was evaluated by qPCR, Western blotting, and immunofluorescence staining. Molecular mechanisms were determined by Co-IP, RIP, and MeRIP. IS injury was determined by neurological behavior score and TTC staining. Mitophagy was observed by TEM. USP18 and fat mass and obesity-associated protein (FTO) expression declined after OGD/R. Dysfunctional mitochondrial and apoptosis in OGD/R-stimulated neurocytes were eliminated by USP18/FTO overexpression via mitophagy activation. USP18-mediated de-ubiquitination was responsible for increasing FTO protein stability. Up-regulation of FTO protein restrained m6A modification of sirtuin6 (SIRT6) in a YTHDF2-dependent manner to enhance SIRT6 expression and subsequent activation of AMPK/PGC-1α/AKT signaling. FTO induced mitophagy to ameliorate nerve cell damage through SIRT6/AMPK/PGC-1α/AKT pathway. Finally, USP18/FTO overexpression relieved IS in rats via triggering SIRT6/AMPK/PGC-1α/AKT axis-mediated mitophagy. USP18 increased FTO protein stability to trigger SIRT6-induced mitophagy, thus mitigating IS. Our data unravel the novel neuroprotective mechanism of USP18 and suggest its potential as a promising treatment target for IS.
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Affiliation(s)
- Mingyu Song
- Department of Neurology, Xiangya Hospital, Central South University, Hunan Province, Changsha, 410008, People's Republic of China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Hunan Province, Changsha, 410008, People's Republic of China
- Clinical Research Center for Cerebrovascular Disease of Hunan Province, Central South University, Hunan Province, No.87, Xiangya Road, Changsha, 410008, People's Republic of China
| | - Fang Yi
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Hunan Province, Changsha, 410008, People's Republic of China
- Department of Geriatric Neurology, Xiangya Hospital, Central South University, Hunan Province, Changsha, 410008, People's Republic of China
| | - Feiyue Zeng
- Department of Radiology, Xiangya Hospital, Central South University, Hunan Province, Changsha, 410008, People's Republic of China
| | - Lan Zheng
- Department of Neurology, Xiangya Hospital, Central South University, Hunan Province, Changsha, 410008, People's Republic of China
| | - Lei Huang
- Department of Neurological Rehabilitation, Hunan Provincial People's Hospital, The First Affiliated Hospital of Hunan Normal University, Hunan Province, Changsha, 410000, People's Republic of China
| | - Xinyu Sun
- Department of Neurology, Xiangya Hospital, Central South University, Hunan Province, Changsha, 410008, People's Republic of China
| | - Qianyi Huang
- Department of Neurology, Xiangya Hospital, Central South University, Hunan Province, Changsha, 410008, People's Republic of China
| | - Jun Deng
- Department of Neurology, Affiliated Hospital of Hunan Academy of Traditional Chinese Medicine, Hunan Province, Changsha, 410000, People's Republic of China
| | - Hong Wang
- Department of Geriatric Neurology, Xiangya Hospital, Central South University, Hunan Province, Changsha, 410008, People's Republic of China
| | - Wenping Gu
- Department of Neurology, Xiangya Hospital, Central South University, Hunan Province, Changsha, 410008, People's Republic of China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Hunan Province, Changsha, 410008, People's Republic of China.
- Clinical Research Center for Cerebrovascular Disease of Hunan Province, Central South University, Hunan Province, No.87, Xiangya Road, Changsha, 410008, People's Republic of China.
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Chen G, Jin Z, Wang X, Yu QH, Hu GB. Danshen injection mitigated the cerebral ischemia/reperfusion injury by suppressing neuroinflammation via the HIF-1α/CXCR4/NF-κB signaling pathway. Neuroreport 2024; 35:601-611. [PMID: 38813902 DOI: 10.1097/wnr.0000000000002043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Danshen injection (DI) is effective in treating cardiovascular and cerebrovascular diseases, including ischemic stroke (IS), including IS, but its mechanism is unclear. A middle cerebral artery occlusion model was used to simulate ischemia/reperfusion (I/R) injury in SD rats. Overexpression of hypoxia-inducible factor 1α (HIF-1α) was achieved by AAV-HIF-1α. Rats were treated with DI or saline. Neurological scores and infarction rates were assessed. I/R damage was examined by HE, 2,3,5-triphenyltetrazolium and Nissl stainings. Expression levels of relative proteins [TNF-α, IL-6, IL-1β, SOD, MDA, ROS, HIF-1α, CXC chemokine receptor 4 (CXCR4) and NF-κB] were measured. DI treatment improved neurological scores and reduced infarction rates, suggesting that it inhibits inflammation and oxidative stress. The expression levels of HIF-1α, CXCR4 and NF-κB were decreased. However, the effectiveness of DI on inflammation inhibition was lost after HIF-1α overexpression. DI may directly target HIF-1α to suppress neuroinflammation and reduce I/R injury by suppressing the HIF-1α/CXCR4/NF-κB signaling pathway.
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Affiliation(s)
- Gao Chen
- School of Medicine, Quzhou College of Technology
| | - Zhan Jin
- School of Medicine, Quzhou College of Technology
| | - Xi Wang
- Urology Department, The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, Zhejiang, China
| | - Qi-Hui Yu
- School of Medicine, Quzhou College of Technology
| | - Gao-Bo Hu
- School of Medicine, Quzhou College of Technology
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Liu Z, He B, Wang X, Peng J, Sun Q, Luo C. Deep cortical microinfarction induced by femtosecond laser in mice: Long-term secondary pathological changes in corresponding superficial cortex. Neurosci Lett 2023; 802:137170. [PMID: 36898650 DOI: 10.1016/j.neulet.2023.137170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/19/2023] [Accepted: 03/06/2023] [Indexed: 03/11/2023]
Abstract
BACKGROUND AND PURPOSE Previous studies have explored the clinical consequences of cortical microinfarction, mainly age-related cognitive decline. However, functional impairment of deep cortical microinfarction remains poorly understood. Based on anatomical knowledge and previous research, we infer that damage to the deep cortex may lead to cognitive deficits and communication impairment between the superficial cortex and thalamus. This study aimed to develop a new model of deep cortical microinfarction based on femtosecond laser ablation of a perforating artery. METHODS Twenty-eight mice were anesthetized with isoflurane, and a cranial window was thinned using a microdrill. Intensively focused femtosecond laser pulses were used to produce perforating arteriolar occlusions and ischemic brain damage was examined using histological analysis. RESULTS Occlusion of different perforating arteries induced different types of cortical microinfarctions. Blocking the perforating artery, which enters the cerebral cortex vertically and has no branches within 300 μm below, can result in deep cortical microinfarction. Moreover, this model showed neuronal loss and microglial activation in the lesions as well as dysplasia of nerve fibers and β-amyloid deposition in the corresponding superficial cortex. CONCLUSIONS We present here a new model of deep cortical microinfarction in mice, in which specific perforating arteries are selectively occluded by a femtosecond laser, and we preliminarily observe several long-term effects related to cognition. This animal model is helpful in investigating the pathophysiology of deep cerebral microinfarction. However, further clinical and experimental studies are required to explore deep cortical microinfarctions in greater molecular and physiological detail.
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Affiliation(s)
- Zhoujing Liu
- Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, No. 628 Zhenyuan Road, Shenzhen 518017, China
| | - Baixuan He
- Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-Sen University, No. 107 Yan Jiang West Road, Guangzhou 510120, China
| | - Xuemin Wang
- Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, No. 628 Zhenyuan Road, Shenzhen 518017, China
| | - Jiamin Peng
- Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, No. 628 Zhenyuan Road, Shenzhen 518017, China
| | - Qiaosong Sun
- Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, No. 628 Zhenyuan Road, Shenzhen 518017, China.
| | - Chuanming Luo
- Department of Neurology, The Seventh Affiliated Hospital, Sun Yat-Sen University, No. 628 Zhenyuan Road, Shenzhen 518017, China.
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Zhang L, Tang S, Ma Y, Liu J, Monnier P, Li H, Zhang R, Yu G, Zhang M, Li Y, Feng J, Qin X. RGMa Participates in the Blood-Brain Barrier Dysfunction Through BMP/BMPR/YAP Signaling in Multiple Sclerosis. Front Immunol 2022; 13:861486. [PMID: 35664003 PMCID: PMC9159795 DOI: 10.3389/fimmu.2022.861486] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/15/2022] [Indexed: 11/25/2022] Open
Abstract
The infiltration of inflammatory cells into the central nervous system (CNS) through the dysfunctional blood–brain barrier (BBB) was critical in the early stages of MS. However, the mechanisms underlying BBB dysfunction remain unknown. Repulsive guidance molecule-a (RGMa) is involved in the pathogenesis of multiple sclerosis (MS), but its role needs to be further explored. This study aimed to evaluate whether RMGa regulates BBB permeability in endothelial cells and MS, and if so, what mechanism may be involved. We created an experimental autoimmune encephalomyelitis (EAE) model in C57BL/6 mice and a human brain microvascular endothelial cell (HBMEC) culture. The permeability of the BBB is measured in response to various interventions. Our results showed that RGMa is expressed in the endothelial cells in HBMECs and EAE mice. RGMa and its signaling counterpart, bone morphogenetic protein 2 (BMP2)/bone morphogenetic protein receptor type II (BMPRII), were gradually increased as the disease progressed. Moreover, as EAE progressed and the BBB was disrupted, the downstream effector, yes-associated protein (YAP), as well as the tight junctional proteins zonula occludens 1 (ZO-1) and claudin-5, decreased significantly. The permeability assay revealed that lentivirus-induced RGMa overexpression in HBMECs caused a significant breakdown of the BBB, whereas RGMa knockdown significantly strengthens the integrity of the BBB. Furthermore, specifically activating BMPR II or inhibiting YAP based on RGMa knockdown results in a significant decrease of ZO-1 and claudin-5 in vitro. On the contrary, inhibition of BMPR II or activation of YAP after upregulating RGMa prevents the downregulation of ZO-1 and claudin-5 in HBMECs. In addition, serum-soluble RGMa (sRGMa) levels were significantly higher in MS patients, particularly in MS patients with Gd+ lesions, indicating that the BBB has been disrupted. In conclusion, this study shows that RGMa causes BBB dysfunction in endothelial cells via BMP2/BMPR II/YAP, resulting in BBB integrity disruption in MS and that it could be a novel therapeutic target for BBB permeability in MS.
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Affiliation(s)
- Lei Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Shi Tang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yue Ma
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Junhang Liu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Philippe Monnier
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Ophthalmology and Vision Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Hang Li
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Rongrong Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Gang Yu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Mengjie Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yongmei Li
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jinzhou Feng
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xinyue Qin
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Sánchez-Huertas C, Herrera E. With the Permission of Microtubules: An Updated Overview on Microtubule Function During Axon Pathfinding. Front Mol Neurosci 2021; 14:759404. [PMID: 34924953 PMCID: PMC8675249 DOI: 10.3389/fnmol.2021.759404] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/01/2021] [Indexed: 01/27/2023] Open
Abstract
During the establishment of neural circuitry axons often need to cover long distances to reach remote targets. The stereotyped navigation of these axons defines the connectivity between brain regions and cellular subtypes. This chemotrophic guidance process mostly relies on the spatio-temporal expression patterns of extracellular proteins and the selective expression of their receptors in projection neurons. Axon guidance is stimulated by guidance proteins and implemented by neuronal traction forces at the growth cones, which engage local cytoskeleton regulators and cell adhesion proteins. Different layers of guidance signaling regulation, such as the cleavage and processing of receptors, the expression of co-receptors and a wide variety of intracellular cascades downstream of receptors activation, have been progressively unveiled. Also, in the last decades, the regulation of microtubule (MT) assembly, stability and interactions with the submembranous actin network in the growth cone have emerged as crucial effector mechanisms in axon pathfinding. In this review, we will delve into the intracellular signaling cascades downstream of guidance receptors that converge on the MT cytoskeleton of the growing axon. In particular, we will focus on the microtubule-associated proteins (MAPs) network responsible of MT dynamics in the axon and growth cone. Complementarily, we will discuss new evidences that connect defects in MT scaffold proteins, MAPs or MT-based motors and axon misrouting during brain development.
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Affiliation(s)
- Carlos Sánchez-Huertas
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández (CSIC-UMH), Alicante, Spain
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Hu Q, Chen Z, Yuan X, Li S, Zhang R, Qin X. Common Polymorphisms in the RGMa Promoter Are Associated With Cerebrovascular Atherosclerosis Burden in Chinese Han Patients With Acute Ischemic Cerebrovascular Accident. Front Cardiovasc Med 2021; 8:743868. [PMID: 34722675 PMCID: PMC8554026 DOI: 10.3389/fcvm.2021.743868] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/27/2021] [Indexed: 12/31/2022] Open
Abstract
Repulsive guidance molecule a (RGMa) plays a vital role in the progression of numerous inflammatory diseases. However, whether it participates in atherosclerosis development is not known. Here, we explored the influence of RGMa in atherogenesis by investigating whether an association exists between functional polymorphisms in the RGMa promoter and cerebrovascular atherosclerosis burden (CAB) in Chinese Han patients diagnosed with acute ischemic cerebrovascular accident. To this end, we conducted a genetic association study on 201 patients with prior diagnoses of acute ischemic stroke or transient ischemic attack recruited from our hospital. After admission, we conducted three targeted single-nucleotide polymorphisms (SNPs) genotyping and evaluated CAB by computed tomography angiography. We used logistic regression modeling to analyze genetic associations. Functional polymorphism analysis indicated an independent association between the rs725458 T allele and increased CAB in patients with acute ischemic cerebrovascular accident [adjusted odds ratio (OR) = 1.66, 95% confidence interval (CI) = 1.01–2.74, P = 0.046]. In contrast, an association between the rs4778099 AA genotype and decreased CAB (adjusted OR = 0.10, 95% CI = 0.01–0.77, P = 0.027) was found. Our Gene Expression Omnibus analysis revealed lower RGMa levels in the atherosclerotic aortas and in the macrophages isolated from plaques than that in the normal aortas and macrophages from normal tissue, respectively. In conclusion, the relationship between RGMa and cerebrovascular atherosclerosis suggests that RGMa has a potential vasoprotective effect. The two identified functional SNPs (rs725458 and rs4778099) we identified in the RGMa promoter are associated with CAB in patients diagnosed with acute ischemic cerebrovascular accident. These findings offer a promising research direction for RGMa-related translational studies on atherosclerosis.
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Affiliation(s)
- Qingzhe Hu
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Zhenlei Chen
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Xiaofan Yuan
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Shucheng Li
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Rongrong Zhang
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Xinyue Qin
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
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Repulsive Guidance Molecule-a and Central Nervous System Diseases. BIOMED RESEARCH INTERNATIONAL 2021; 2021:5532116. [PMID: 33997000 PMCID: PMC8112912 DOI: 10.1155/2021/5532116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/27/2021] [Indexed: 12/12/2022]
Abstract
Repulsive guidance molecule-a (RGMa) is a member of glycosylphosphatidylinositol- (GPI-) anchored protein family, which has axon guidance function and is widely involved in the development and pathological processes of the central nervous system (CNS). On the one hand, the binding of RGMa and its receptor Neogenin can regulate axonal guidance, differentiation of neural stem cells into neurons, and the survival of these cells; on the other hand, RGMa can inhibit functional recovery of CNS by inhibiting axonal growth. A number of studies have shown that RGMa may be involved in the pathogenesis of CNS diseases, such as multiple sclerosis, neuromyelitis optica spectrum diseases, cerebral infarction, spinal cord injury, Parkinson's disease, and epilepsy. Targeting RGMa can enhance the functional recovery of CNS, so it may become a promising target for the treatment of CNS diseases. This article will comprehensively review the research progression of RGMa in various CNS diseases up to date.
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Wen YT, Huang CW, Liu CP, Chen CH, Tu CM, Hwang CS, Chen YH, Chen WR, Lin KL, Ho YC, Chen TC, Tsai RK. Inhibition of Retinal Ganglion Cell Loss By a Novel ROCK Inhibitor (E212) in Ischemic Optic Nerve Injury Via Antioxidative and Anti-Inflammatory Actions. Invest Ophthalmol Vis Sci 2021; 62:21. [PMID: 34015079 PMCID: PMC8142697 DOI: 10.1167/iovs.62.6.21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 03/24/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose This study investigated the neuroprotective effects of administration of ROCK inhibitor E212 on ischemic optic neuropathy. Methods Rats received an intravitreal injection of either E212 or PBS immediately after optic nerve infarct. The oxidative stress in the retina was detected by performing superoxide dismutase activity and CellROX assays. The integrity of retinal pigment epithelium was determined by staining of zona occludens 1. The visual function, retinal ganglion cell (RGC) density, and RGC apoptosis were determined by using flash visual-evoked potential analysis, retrograde FluoroGold labeling, and TdT-dUTP nick end-labeling assay. Macrophage infiltration was detected by staining for ED1. The protein levels of TNF-α, p-CRMP, p-AKT1, p-STAT3, and CD206 were evaluated using Western blotting. Results Administration of E212 resulted in a 1.23-fold increase in the superoxide dismutase activity of the retina and 2.28-fold decrease in RGC-produced reactive oxygen species as compared to the levels observed upon treatment with PBS (P < 0.05). Moreover, E212 prevented the disruption of the blood-retinal barrier (BRB) in contrast to PBS. The P1-N2 amplitude and RGC density in the E212-treated group were 1.75- and 2.05-fold higher, respectively, than those in the PBS-treated group (P < 0.05). The numbers of apoptotic RGCs and macrophages were reduced by 2.93- and 2.54-fold, respectively, in the E212-treated group compared with those in the PBS-treated group (P < 0.05). The levels of p-AKT1, p-STAT3, and CD206 were increased, whereas those of p-PTEN, p-CRMP2, and TNF-α were decreased after treatment with E212 (P < 0.05). Conclusions Treatment with E212 suppresses oxidative stress, BRB disruption, and neuroinflammation to protect the visual function in ischemic optic neuropathy.
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Affiliation(s)
- Yao-Tseng Wen
- Institute of Eye Research, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Ching-Wen Huang
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
| | - Chih-Peng Liu
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan
| | - Chih-Hung Chen
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan
| | - Chia-Mu Tu
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan
| | - Chrong-Shiong Hwang
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan
| | - Yi-Hsun Chen
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan
| | - Wan-Ru Chen
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan
| | - Keh-Liang Lin
- Department of Medical laboratory and Biotechnology, Chung Shan Medical University, Taichung, Taiwan
| | - Yu-Chieh Ho
- Institute of Eye Research, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Ta-Ching Chen
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Rong-Kung Tsai
- Institute of Eye Research, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
- Doctoral Degree Program in Translational Medicine, Tzu Chi University and Academia Sinica, Hualien, Taiwan
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Hou ST. The regulatory and enzymatic functions of CRMPs in neuritogenesis, synaptic plasticity, and gene transcription. Neurochem Int 2020; 139:104795. [PMID: 32652266 DOI: 10.1016/j.neuint.2020.104795] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/18/2020] [Accepted: 06/22/2020] [Indexed: 12/13/2022]
Abstract
Collapsin response mediator proteins (CRMPs) are ubiquitously expressed in neurons from worms to humans. A cardinal feature of CRMPs is to mediate growth cone collapse in response to Semaphorin-3A signaling through interactions with cytoskeletal proteins. These are critical regulatory roles that CRMPs play during neuritogenesis and neural network formation. Through post-translational modifications, such as phosphorylation, O-GlcNAcylation, SUMOylation, and proteolytic cleavage, CRMPs participate in synaptic plasticity by modulating NMDA receptors, L- and N-type voltage-gated calcium channels (VGCCs), thus affecting neurotransmitter release. CRMPs also possess histone deacetylase (HDAC) activity, which deacetylates histone H4 during neuronal death. Calcium-dependent proteolytic cleavage of CRMPs results in the truncation of CRMPs, producing a large 54 kD fragment (p54). Translocation of the p54 fragment into the nucleus leads to deacetylation of nuclear histone H4 and de-repression of transcription factor E2F1 expression. Increased expression of E2F1 elevates the expression of genes in cell cycle and death. These new and exciting studies lead to the realization that CRMPs are multifunctional proteins with both regulatory and enzymatic functions. Increasing numbers of studies associate these functions of CRMPs with the development of mental and neurological disorders, such as schizophrenia, Alzheimer's diseases, brain trauma, and stroke. This review focuses on new evidence showing the regulatory and enzymatic functions of CRMPs and highlights recent understandings of CRMPs' roles in neurological diseases.
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Affiliation(s)
- Sheng-Tao Hou
- Brain Research Centre and Department of Biology, Southern University of Science and Technology, 1088 Xueyuan Blvd, Nanshan District, Shenzhen, Guangdong Province, 518055, PR China; Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
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Nakamura F, Ohshima T, Goshima Y. Collapsin Response Mediator Proteins: Their Biological Functions and Pathophysiology in Neuronal Development and Regeneration. Front Cell Neurosci 2020; 14:188. [PMID: 32655376 PMCID: PMC7325199 DOI: 10.3389/fncel.2020.00188] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 05/29/2020] [Indexed: 12/19/2022] Open
Abstract
Collapsin response mediator proteins (CRMPs), which consist of five homologous cytosolic proteins, are one of the major phosphoproteins in the developing nervous system. The prominent feature of the CRMP family proteins is a new class of microtubule-associated proteins that play important roles in the whole process of developing the nervous system, such as axon guidance, synapse maturation, cell migration, and even in adult brain function. The CRMP C-terminal region is subjected to posttranslational modifications such as phosphorylation, which, in turn, regulates the interaction between the CRMPs and various kinds of proteins including receptors, ion channels, cytoskeletal proteins, and motor proteins. The gene-knockout of the CRMP family proteins produces different phenotypes, thereby showing distinct roles of all CRMP family proteins. Also, the phenotypic analysis of a non-phosphorylated form of CRMP2-knockin mouse model, and studies of pharmacological responses to CRMP-related drugs suggest that the phosphorylation/dephosphorylation process plays a pivotal role in pathophysiology in neuronal development, regeneration, and neurodegenerative disorders, thus showing CRMPs as promising target molecules for therapeutic intervention.
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Affiliation(s)
- Fumio Nakamura
- Department of Biochemistry, Tokyo Women's Medical University, Tokyo, Japan
| | - Toshio Ohshima
- Department of Life Science and Medical Bio-Science, Waseda University, Tokyo, Japan
| | - Yoshio Goshima
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
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12
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Zhang Y, Wang X, Cheng J, Lin Y, Yang L, Cao Z, Yang Y. Changes of fractional anisotropy and RGMa in crossed cerebellar diaschisis induced by middle cerebral artery occlusion. Exp Ther Med 2019; 18:3595-3602. [PMID: 31602236 DOI: 10.3892/etm.2019.7986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 07/09/2018] [Indexed: 01/18/2023] Open
Abstract
Crossed cerebellar diaschisis (CCD) is the phenomenon of hypoperfusion and hypometabolism of the contralateral cerebellar hemisphere caused by dysfunction of the associated supratentorial region. The aim of the present study was to analyze the changes in fractional anisotropy (FA) in CCD induced by middle cerebral artery occlusion (MCAO) using magnetic resonance-diffusion tensor imaging (MR-DTI). Furthermore, the role of repulsive guidance molecule a (RGMa) in CCD was assessed by measuring RGMa expression using histochemical analysis. In the present study, the cerebellar hemisphere was serially scanned with T2-weighted, serial diffusion-weighted and diffusion tensor (DT) imaging using a 3.0T GE Signa HDxt Scanner to analyze the changes in FA over 72 h. Subsequently, immunohistochemistry analyses of the corresponding cerebellar hemisphere sections were performed to assess the expression of RGMa. Results indicated that FA of both sides of the cerebellar hemisphere, particularly that of the contralateral cerebellar hemisphere (right side) derived from DTI, was reduced during the 72-h time period following MCAO, and the decrease was maximal and statistically significant at 12 h (P<0.05). Immunohistochemistry analysis revealed a significant increase in the expression of RGMa protein in the affected region of the contralateral cerebellar hemisphere (right side) at 24 h following MCAO injury (P<0.05). Furthermore, the expression of RGMa and FA was negatively correlated in MCAO (P<0.05). The results suggest that MR-DTI is an important assessment to evaluate changes of FA in CCD induced by MCAO. Furthermore, the present results suggest that RGMa, which was negatively correlated with FA in MCAO rats, may serve an important role in CCD.
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Affiliation(s)
- Yong Zhang
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Xiao Wang
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Jingliang Cheng
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Yanan Lin
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Lu Yang
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Zhenghao Cao
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Yunjun Yang
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
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Song M, Tian F, Xia H, Xie Y. Repulsive guidance molecule a suppresses seizures and mossy fiber sprouting via the FAK‑p120RasGAP‑Ras signaling pathway. Mol Med Rep 2019; 19:3255-3262. [PMID: 30816469 DOI: 10.3892/mmr.2019.9951] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 01/21/2019] [Indexed: 11/05/2022] Open
Abstract
Repulsive guidance molecule a (RGMa) is a membrane‑associated glycoprotein that regulates axonal guidance and inhibits axon outgrowth. In our previous study, we hypothesized that RGMa may be involved in temporal lobe epilepsy (TLE) via the repulsive guidance molecule a (RGMa)‑focal adhesion kinase (FAK)‑Ras signaling pathway. To investigate the role of RGMa in epilepsy, recombinant RGMa protein and FAK inhibitor 14 was intracerebroventricularly injected into a pentylenetetrazol (PTZ) kindling model and Timm staining, co‑immunoprecipitation and western blotting analyses were subsequently performed. The results of the present study revealed that intracerebroventricular injection of recombinant RGMa protein reduced the phosphorylation of FAK (Tyr397) and intracerebroventricular injection of FAK inhibitor 14 reduced the interaction between FAK and p120GAP, as wells as Ras expression. Recombinant RGMa protein and FAK inhibitor 14 exerted seizure‑suppressant effects; however, recombinant RGMa protein but not FAK inhibitor 14 suppressed mossy fiber sprouting in the PTZ kindling model. Collectively, these results demonstrated that RGMa may be considered as a potential therapeutic agent for epilepsy, and that RGMa may exert the aforementioned biological effects partly via the FAK‑p120GAP‑Ras signaling pathway.
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Affiliation(s)
- Mingyu Song
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Fafa Tian
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Huang Xia
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Yuanyuan Xie
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
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Chen X, Yuan R, Gao L, Huang C, Fan W, Ye J, Chen C. Induction of CRMP-2 phosphorylation by CDK5 restricts the repair of damaged optic nerve. J Cell Physiol 2018; 234:11240-11246. [PMID: 30537069 DOI: 10.1002/jcp.27778] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 10/30/2018] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To study the mechanism of collapsin response mediator protein-2 (CRMP-2) phosphorylation changes and cyclin-dependent kinase 5 (CDK5) expression after optic nerve injury. METHODS Optic nerve injury rat models were constructed, the messenger RNA (mRNA) level of CRMP-2 in optic nerve tissues was determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) after building models 0, 3, 7, and 14 days. The protein expression of CRMP-2, phospho-CRMP-2 (p-CRMP-2), and CDK5 were also determined by western blot analysis. Lentivirus overexpressing CRMP-2 and CRMP-2 small interfering RNA (siRNA) plasmid were designed and transfected to retina ganglion cells (RGCs), and then the neurites outgrowth of RGCs were cultured with CDK5 inhibitor or CDK5 activator was determined by tubulin staining. Inhibition on CDK5 promotes injured optic nerve by using carrying CDK5 siRNA inject into vitreous chamber. RESULTS There was no significant change in CRMP-2 expression in optic nerve injury rat, while p-CRMP-2 expression was evidently increased compared with sham operation group. The expression level of CDK5 in optic nerve tissue was upregulated after optic nerve injury in rat, and the upward trend of p-CRMP-2 and CDK5 was consistent with the time after the injury was prolonged. Inhibition on CDK5 evidently decreased the expression of p-CRMP-2. CDK5 siRNA had an obvious repair effect on the injured optic nerve. CONCLUSION The increase of CDK5 activity can lead to CRMP-2 hyperphosphorylation, which results in the difficult repair of damaged optic nerve. Therefore, inhibition on CDK5 could promote the repair of damaged optic nerve.
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Affiliation(s)
- Xiaofan Chen
- Department of Ophthalmology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Rongdi Yuan
- Department of Ophthalmology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Ling Gao
- Department of Ophthalmology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Chanjuan Huang
- Department of Ophthalmology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Wei Fan
- Department of Ophthalmology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Jian Ye
- Department of Ophthalmology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Chunlin Chen
- Department of Ophthalmology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
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Li XB, Ding MX, Ding CL, Li LL, Feng J, Yu XJ. Toll‑Like receptor 4 promotes the phosphorylation of CRMP2 via the activation of Rho‑kinase in MCAO rats. Mol Med Rep 2018; 18:342-348. [PMID: 29749502 PMCID: PMC6059689 DOI: 10.3892/mmr.2018.8968] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 04/20/2018] [Indexed: 02/05/2023] Open
Abstract
The mechanism associated with Toll‑like receptor 4 (TLR4) in neurological injury remains unclear. The aim of the present study was to investigate the pathology of TLR4 in middle cerebral artery occlusion (MCAO)/reperfusion rat models via the regulation of collapsin response mediator protein 2 (CRMP2) phosphorylation. The modified neurological severity score (mNSS) was applied to assess neurological recovery. Immunofluorescence and western blotting were used to detect the protein expressions of TLR4, Rho‑associated protein kinase 2 (ROCK‑II) and CRMP2 following the intracerebroventricular administration of TLR4‑specific agonist, lipopolysaccharide (LPS) and TLR4‑neutralizing antibody, the ROCK‑II specific inhibitor Y‑27632 or LPS+Y‑27632 30 min prior to MCAO. The expression levels of TLR4 and the phosphorylation of CRMP2 significantly increased in response to LPS‑mediated induction and/or MCAO; however, they were reversed by treatment with LPS+TLR4‑neutralizing antibody. Y‑27632 decreased the expression of ROCK‑II and phosphorylated (p)‑CRMP2, and suppressed the increased ROCK‑II and p‑CRMP2 induced by LPS; however, no effect on the levels of TLR4 expression was observed. The neurological function as measured by mNSS score was reduced in the LPS group when compared with the MCAO group, whereas the LPS+Y‑27632 group reversed the reduced neurological function at 7 and 14 days post‑MCAO. The results of the present study suggested that TLR4 may promote the phosphorylation of CRMP2 via the activation of ROCK‑II in MCAO rats, which further characterizes the pathological mechanism of TLR4 in stroke, and that modulation of TLR4 could be a potential target to limit secondary post‑stroke brain damage.
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Affiliation(s)
- Xue-Bo Li
- Department of Forensic Medicine, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
- Key Laboratory of Evidence Identification in Universities of Shandong, Shandong University of Political Science and Law, Jinan, Shandong 250014, P.R. China
| | - Ming-Xia Ding
- Department of Obstetrics and Gynecology, The Second Hospital of Shandong University, Jinan, Shandong 250014, P.R. China
| | - Chun-Li Ding
- Key Laboratory of Evidence Identification in Universities of Shandong, Shandong University of Political Science and Law, Jinan, Shandong 250014, P.R. China
| | - Liang-Liang Li
- Key Laboratory of Evidence Identification in Universities of Shandong, Shandong University of Political Science and Law, Jinan, Shandong 250014, P.R. China
| | - Jinzhou Feng
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Xiao-Jun Yu
- Department of Forensic Medicine, Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
- Correspondence to: Dr Xiao-Jun Yu, Department of Forensic Medicine, Shantou University Medical College, 22 Xinling Road, Shantou, Guangdong 515041, P.R. China, E-mail:
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Li M, Wen Y, Zhang R, Xie F, Zhang G, Qin X. Adenoviral vector-induced silencing of RGMa attenuates blood-brain barrier dysfunction in a rat model of MCAO/reperfusion. Brain Res Bull 2018; 142:54-62. [PMID: 29935233 DOI: 10.1016/j.brainresbull.2018.06.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 06/15/2018] [Accepted: 06/18/2018] [Indexed: 12/29/2022]
Abstract
BACKGROUND Repulsive guidance molecule A (RGMa) is implicated in focal cerebral ischemia-reperfusion (I/R) injury, but its mechanisms are still largely unknown. This work focused on the effects of RGMa on the blood-brain barrier (BBB) after focal cerebral I/R injury. METHODS Sprague-Dawley (SD) rats were randomly divided into four groups: sham, middle cerebral artery occlusion (MCAO)/reperfusion (I/R), MCAO/reperfusion administered recombinant adenovirus expressing sh-con (I/R + sh-con) and MCAO/reperfusion administered recombinant adenovirus expressing sh-RGMa (I/R + sh-RGMa) groups. Infarct volume, brain edema and neurological scores were evaluated at 3 day after reperfusion. Evens blue leakage and transmission electron microscopy was performed. And the expression level of claudin-5 and ZO-1, CDC-42 and PAK-1, RGMa were detected by western blot. RESULTS Compared with I/R or I/R + sh-con groups, I/R + sh-RGMa group showed smaller infarction volume, attenuated brain edema, improved neurological scores and better BBB integrity, such as reduced Evans blue leakage and ultra-structural change. We also observed improved BBB function followed by down-regulation of MMP-9 and up-regulation of claudin-5 and ZO-1 in the I/R + sh-RGMa group. In addition, up-regulation of the CDC-42 and PAK-1 in the I/R + sh-RGMa group was obtained. CONCLUSIONS RGMa may be involved in I/R injury associated with BBB dysfunction via the CDC-42/PAK-1 signal pathway and may be a promising therapeutic target for I/R injury.
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Affiliation(s)
- Min Li
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China; Department of Neurology, Inner Mongolia People's Hospital, Hohhot, China
| | - Yuetao Wen
- Department of Neurosurgery, University-Town Hospital of Chongqing Medical University, Chongqing, China
| | - Rongrong Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Fei Xie
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Gang Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xinyue Qin
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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RGMa mediates reactive astrogliosis and glial scar formation through TGFβ1/Smad2/3 signaling after stroke. Cell Death Differ 2018; 25:1503-1516. [PMID: 29396549 PMCID: PMC6113216 DOI: 10.1038/s41418-018-0058-y] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 12/22/2017] [Accepted: 12/27/2017] [Indexed: 01/11/2023] Open
Abstract
In response to stroke, astrocytes become reactive astrogliosis and are a major component of a glial scar. This results in the formation of both a physical and chemical (production of chondroitin sulfate proteoglycans) barrier, which prevent neurite regeneration that, in turn, interferes with functional recovery. However, the mechanisms of reactive astrogliosis and glial scar formation are poorly understood. In this work, we hypothesized that repulsive guidance molecule a (RGMa) regulate reactive astrogliosis and glial scar formation. We first found that RGMa was strongly expressed by reactive astrocytes in the glial scar in a rat model of middle cerebral artery occlusion/reperfusion. Genetic or pharmacologic inhibition of RGMa in vivo resulted in a strong reduction of reactive astrogliosis and glial scarring as well as in a pronounced improvement in functional recovery. Furthermore, we showed that transforming growth factor β1 (TGFβ1) stimulated RGMa expression through TGFβ1 receptor activin-like kinase 5 (ALK5) in primary cultured astrocytes. Knockdown of RGMa abrogated key steps of reactive astrogliosis and glial scar formation induced by TGFβ1, including cellular hypertrophy, glial fibrillary acidic protein upregulation, cell migration, and CSPGs secretion. Finally, we demonstrated that RGMa co-immunoprecipitated with ALK5 and Smad2/3. TGFβ1-induced ALK5-Smad2/3 interaction and subsequent phosphorylation of Smad2/3 were impaired by RGMa knockdown. Taken together, we identified that after stroke, RGMa promotes reactive astrogliosis and glial scar formation by forming a complex with ALK5 and Smad2/3 to promote ALK5-Smad2/3 interaction to facilitate TGFβ1/Smad2/3 signaling, thereby inhibiting neurological functional recovery. RGMa may be a new therapeutic target for stroke.
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18
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Wang Y, Zhang R, Xing X, Guo J, Xie F, Zhang G, Qin X. Repulsive guidance molecule a suppresses angiogenesis after ischemia/reperfusion injury of middle cerebral artery occlusion in rats. Neurosci Lett 2017; 662:318-323. [PMID: 29061393 DOI: 10.1016/j.neulet.2017.10.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 09/26/2017] [Accepted: 10/19/2017] [Indexed: 10/18/2022]
Abstract
Repulsive guidance molecule a (RGMa) has now emerged as a molecule with pleiotropic roles, including repulsion, adhesion, migration and differentiation in the nervous system. In this study, adult male Sprague-Dawley (SD) rats received 90-min middle cerebral artery occlusion (MCAO) to observe RGMa/neogenin expression sites after ischemia/reperfusion injury and changes in angiogenesis after treatment with RNA interference using RGMa-specific recombinant adenovirus rAd5-shRNA-RGMa (rAd-shRGMa). To clarify how RGMa mediates angiogenesis, the RGMa function-blocking peptide six fibronectin type III (6FNIII) was also administered, and corresponding changes in vascular endothelial growth factor (VEGF), angiopoietin-2 (Ang2), angiopoietin-1 (Ang1), and brain derived neurotrophic factor (BDNF) were determined by western blotting. Both RGMa and its receptor neogenin were expressed in neurons and vessel endothelial cells after ischemia/reperfusion injury, and angiogenesis, coupled with functional recovery, was enhanced after RNA interference against RGMa compared with the vehicle groups. VEGF, Ang2, Ang1 and BDNF expression levels were significantly increased after intervention with rAd-shRGMa or 6FNIII. Thus, RGMa might suppress angiogenesis via VEGF, Ang2, Ang1 and BDNF after cerebral ischemia/reperfusion injury, which has therapeutic potential by reducing these endogenous detrimental mechanisms.
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Affiliation(s)
- Yu Wang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China; Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Rongrong Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Xiangfeng Xing
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Jia Guo
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Fei Xie
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Gang Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Xinyue Qin
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China.
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Zhang G, Wang R, Cheng K, Li Q, Wang Y, Zhang R, Qin X. Repulsive Guidance Molecule a Inhibits Angiogenesis by Downregulating VEGF and Phosphorylated Focal Adhesion Kinase In Vitro. Front Neurol 2017; 8:504. [PMID: 29018403 PMCID: PMC5623191 DOI: 10.3389/fneur.2017.00504] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 09/08/2017] [Indexed: 01/13/2023] Open
Abstract
Repulsive guidance molecule a (RGMa) is a major neuron guidance factor in central nervous systems. We previously found that inhibition of RGMa could greatly enhance neural function rehabilitation in rats after MCAO/reperfusion. Neuron guidance factors are often regulators of angiogenesis. However, the effect of RGMa on angiogenesis and its mechanisms remain to be determined. Here, we investigated the effect of RGMa on endothelial cell (EC) proliferation, migration, tube formation, and cytoskeleton reassembly. The addition of recombinant RGMa significantly decreased the proliferation, migration, and tube formation of ECs. It also decreased the level of phosphorylated focal adhesion kinase (p-FAK Tyr397). Furthermore, the F-actin of the cytoskeleton assembly was obviously suppressed, with decreased filopodia and lamellipodia after the addition of RGMa. Knockout of neogenin or Unc5b significantly diminished RGMa’s inhibition of EC migration, tube formation, and cytoskeleton reassembly. RGMa-induced p-FAK (Tyr397) decrease was also abolished by knockout of neogenin or Unc5b. These results indicate that RGMa may be a negative regulator of angiogenesis through downregulating VEGF and p-FAK (Tyr397) via neogenin and Unc5b in vitro.
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Affiliation(s)
- Gang Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Rong Wang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Ke Cheng
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Qi Li
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yu Wang
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Rongrong Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xinyue Qin
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Zheng J, Liu Z, Li W, Tang J, Zhang D, Tang X. Lithium posttreatment confers neuroprotection through glycogen synthase kinase-3β inhibition in intracerebral hemorrhage rats. J Neurosurg 2016; 127:716-724. [PMID: 27739937 DOI: 10.3171/2016.7.jns152995] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Inflammation and apoptosis are two key factors contributing to secondary brain injury after intracerebral hemorrhage (ICH). The objective of this study was to evaluate the effects of lithium posttreatment on behavior, brain atrophy, inflammation, and perihematomal cell death. Furthermore, the authors aimed to determine the role of the pro-apoptotic glycogen synthase kinase-3β (GSK-3β) after experimental ICH. METHODS Male Sprague-Dawley rats (n = 108) were subjected to intracerebral infusion of semicoagulated autologous blood. Window of opportunity and dose optimization studies of lithium on ICH-induced injury were performed by measuring neurological deficits. Animals with ICH received vehicle administration or lithium posttreatment (60 mg/kg) for up to 21 days. Hemispheric atrophy was evaluated. Perihematomal cell death was quantified through terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL). The number of myeloperoxidase (MPO)-positive neutrophils and OX42-positive microglia in the perihematomal areas were calculated. Western blotting was used for the quantification of GSK-3β, heat shock protein 70 (HSP70), nuclear factor-κB p65 (NF-κB p65), and cy-clooxygenase-2 (COX-2). RESULTS Lithium, at a dose of 60 mg/kg initiated from 2 hours after injury, exhibited the best effects of improving neurological outcomes 3, 5, 7, 14, 21, and 28 days after ICH, reduced the hemispheric atrophy at 42 days after surgery, and reduced the number of TUNEL-positive cells, MPO-positive neutrophils, and OX42-positive microglia in the perihematomal areas. Furthermore, lithium posttreatment modulated GSK-3β, increased HSP70, and decreased NF-κB p65 and COX-2 expression in the ipsilateral hemisphere. CONCLUSIONS Lithium posttreatment at a dose of 60 mg/kg, initiated beginning 2 hours after injury, improves functional and morphological outcomes, and inhibits inflammation and perihematomal cell death in a rat model of semicoagulated autologous blood ICH through inactivation of GSK-3β.
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Affiliation(s)
- Jian Zheng
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical University, Heilongjiang
| | - Zhen Liu
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical University, Heilongjiang
| | - Weishan Li
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical University, Heilongjiang
| | - Jiaxin Tang
- The Ninth People's Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai; and
| | - Dongwei Zhang
- Department of General Surgery, The Second Affiliated Hospital of Harbin Medical University, Heilongjiang, China
| | - Xiaobo Tang
- Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical University, Heilongjiang
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Zuo YC, Xiong NX, Zhao HY. Stereotactic injection of shrna GSK-3β-AAV promotes axonal regeneration after spinal cord injury. ACTA ACUST UNITED AC 2016; 36:548-553. [PMID: 27465331 DOI: 10.1007/s11596-016-1623-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 06/25/2016] [Indexed: 01/14/2023]
Abstract
Evidence suggested that glycogen synthase kinase-3β (GSK-3β) is involved in Nogo-66 inhibiting axonal regeneration in vitro, but its effect in vivo was poorly understood. We showed that stereotactic injection of shRNA GSK-3β-adeno associated virus (GSK-3β-AAV) diminished syringomyelia and promoted axonal regeneration after spinal cord injury (SCI), using stereotactic injection of shRNA GSK-3β-AAV (tested with Western blotting and RT-PCR) into the sensorimotor cortex of rats with SCI and by the detection of biotin dextran amine (BDA)-labeled axonal regeneration. We also determined the right position to inject into the sensorimotor cortex. Our findings consolidate the hypothesis that downregulation of GSK-3β promotes axonal regeneration after SCI.
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Affiliation(s)
- Yu-Chao Zuo
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Department of Neurosurgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Nan-Xiang Xiong
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Hong-Yang Zhao
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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Xu X, Gao Y, Zhai Z, Zhang S, Shan F, Feng J. Repulsive guidance molecule a blockade exerts the immunoregulatory function in DCs stimulated with ABP and LPS. Hum Vaccin Immunother 2016; 12:2169-2180. [PMID: 26986456 DOI: 10.1080/21645515.2016.1164361] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Repulsive guidance molecule a (RGMa) is an axonal guidance molecule that has recently found to exert function in immune system. This study evaluated the function of RGMa in modulation of dendritic cells (DCs) function stimulated with Achyranthes bidentata polysaccharide (ABP) and lipopolysaccharide (LPS) using a RGMa-neutralizing antibody. Compared with the Control-IgG/ABP and Control-IgG/LPS groups, DCs in the Anti-RGMa/ABP and Anti-RGMa/LPS groups 1) showed small, round cells with a few cell processes and organelles, and many pinocytotic vesicles; 2) had decreased MHC II, CD86, CD80, and CD40 expression; 3) displayed the decreased IL-12p70, IL-1β and TNF-α levels and increased IL-10 secretion; 4) had a high percentage of FITC-dextran uptake; and 5) displayed a reduced ability to drive T cell proliferation and reinforced T cell polarization toward a Th2 cytokine pattern. We conclude that DCs treated with RGMa-neutralizing antibodies present with tolerogenic and immunoregulatory characteristics, which provides new insights into further understanding of the function of RGMa.
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Affiliation(s)
- Xuxu Xu
- a Department of Neurology, Shengjing Hospital , Affiliated Hospital of China Medical University , Shenyang , PR China
| | - Yan Gao
- a Department of Neurology, Shengjing Hospital , Affiliated Hospital of China Medical University , Shenyang , PR China
| | - Zhiyong Zhai
- a Department of Neurology, Shengjing Hospital , Affiliated Hospital of China Medical University , Shenyang , PR China
| | - Shuo Zhang
- a Department of Neurology, Shengjing Hospital , Affiliated Hospital of China Medical University , Shenyang , PR China
| | - Fengping Shan
- b Department of Immunology, School of Basic Medical Science , China Medical University , Shenyang , PR China
| | - Juan Feng
- a Department of Neurology, Shengjing Hospital , Affiliated Hospital of China Medical University , Shenyang , PR China
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PI3K mediated activation of GSK-3β reduces at-level primary afferent growth responses associated with excitotoxic spinal cord injury dysesthesias. Mol Pain 2015; 11:35. [PMID: 26093674 PMCID: PMC4475622 DOI: 10.1186/s12990-015-0041-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 06/11/2015] [Indexed: 02/08/2023] Open
Abstract
Background Neuropathic pain and sensory abnormalities are a debilitating secondary consequence of spinal cord injury (SCI). Maladaptive structural plasticity is gaining recognition for its role in contributing to the development of post SCI pain syndromes. We previously demonstrated that excitotoxic induced SCI dysesthesias are associated with enhanced dorsal root ganglia (DRG) neuronal outgrowth. Although glycogen synthase kinase-3β (GSK-3β) is a known intracellular regulator neuronal growth, the potential contribution to primary afferent growth responses following SCI are undefined. We hypothesized that SCI triggers inhibition of GSK-3β signaling resulting in enhanced DRG growth responses, and that PI3K mediated activation of GSK-3β can prevent this growth and the development of at-level pain syndromes. Results Excitotoxic SCI using intraspinal quisqualic acid (QUIS) resulted in inhibition of GSK-3β in the superficial spinal cord dorsal horn and adjacent DRG. Double immunofluorescent staining showed that GSK-3βP was expressed in DRG neurons, especially small nociceptive, CGRP and IB4-positive neurons. Intrathecal administration of a potent PI3-kinase inhibitor (LY294002), a known GSK-3β activator, significantly decreased GSK-3βP expression levels in the dorsal horn. QUIS injection resulted in early (3 days) and sustained (14 days) DRG neurite outgrowth of small and subsequently large fibers that was reduced with short term (3 days) administration of LY294002. Furthermore, LY294002 treatment initiated on the date of injury, prevented the development of overgrooming, a spontaneous at-level pain related dysesthesia. Conclusions QUIS induced SCI resulted in inhibition of GSK-3β in primary afferents and enhanced at-level DRG intrinsic growth (neurite elongation and initiation). Early PI3K mediated activation of GSK-3β attenuated QUIS-induced DRG neurite outgrowth and prevented the development of at-level dysesthesias.
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Li H, Zhu YH, Chi C, Wu HW, Guo J. Role of cytoskeleton in axonal regeneration after neurodegenerative diseases and CNS injury. Rev Neurosci 2015; 25:527-42. [PMID: 24622784 DOI: 10.1515/revneuro-2013-0062] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 02/09/2014] [Indexed: 11/15/2022]
Abstract
With the occurrence of neurodegenerative diseases, such as Alzheimer's and Parkinson's disease, a number of well-functioning neurons need to be developed to make up for the loss of neurons and to restore the brain functions. Unfortunately, because the axons cannot regenerate well, brain function cannot be well compensated for even with the increasing number of newborn neurons, let alone the reformation of neural network. Cytoskeletal proteins play a crucial role in regeneration of axon. In this review, we summarize some cytoskeletal proteins, for instance, actin and actin-binding proteins, as well as tubulin and microtubule-associated proteins, and more importantly, their roles in the regulation of axonal regeneration in the brain. It will provide new opportunities for axonal regeneration after brain damage and will even bring new treatments to patients with neurodegenerative diseases.
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Song MY, Tian FF, Wang YZ, Huang X, Guo JL, Ding DX. Potential roles of the RGMa-FAK-Ras pathway in hippocampal mossy fiber sprouting in the pentylenetetrazole kindling model. Mol Med Rep 2014; 11:1738-44. [PMID: 25420768 PMCID: PMC4270322 DOI: 10.3892/mmr.2014.2993] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 08/01/2014] [Indexed: 11/23/2022] Open
Abstract
Mossy fiber sprouting (MFS) is a unique feature of chronic epilepsy. However, the molecular signals underlying MFS are still unclear. The repulsive guidance molecule A (RGMa) appears to contribute to axon growth and axonal guidance, and may exert its biological effects by dephosphorylating focal adhesion kinase (FAK) at Tyr397, then regulating the activation of Ras. The objective of this study was to explore the expression patterns of RGMa, FAK (Tyr397) and Ras in epileptogenesis, and their correlation with MFS. The epileptic models were established by intraperitoneal pentylenetetrazole (PTZ) injection of Sprague-Dawley rats. At 3 days and at 1, 2, 4 and 6 weeks after the first PTZ injection, Timm staining was scored at different time points in the CA3 region of the hippocampus and dentate gyrus. The protein levels of RGMa, FAK (Tyr397) and Ras were analyzed at different time points in the CA3 region of the hippocampus using immunofluorescence, immunohistochemistry and western blot analysis. Compared with the control (saline-injected) group, the expression of RGMa in the CA3 area was significantly downregulated (P<0.05) from 3 days and still maintained the low expression at 6 weeks in the PTZ group. The expression of FAK (Tyr397) and Ras was upregulated (P<0.05) in the PTZ groups. The Timm score in the CA3 region was significantly higher than that in the control group at different time points and reached a peak at 4 weeks. In the CA3 region, no obvious distinction was observed at the different time points in the control group. To the best of our knowledge, these are the first results to indicate that the RGMa-FAK-Ras pathway may be involved in MFS and the development of temporal lobe epilepsy.
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Affiliation(s)
- Ming-Yu Song
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Fa-Fa Tian
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Yu-Zhong Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Xia Huang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Jia-Ling Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Dong-Xue Ding
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
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Liz MA, Mar FM, Santos TE, Pimentel HI, Marques AM, Morgado MM, Vieira S, Sousa VF, Pemble H, Wittmann T, Sutherland C, Woodgett JR, Sousa MM. Neuronal deletion of GSK3β increases microtubule speed in the growth cone and enhances axon regeneration via CRMP-2 and independently of MAP1B and CLASP2. BMC Biol 2014; 12:47. [PMID: 24923837 PMCID: PMC4229956 DOI: 10.1186/1741-7007-12-47] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 06/07/2014] [Indexed: 02/08/2023] Open
Abstract
Background In the adult central nervous system, axonal regeneration is abortive. Regulators of microtubule dynamics have emerged as attractive targets to promote axonal growth following injury as microtubule organization is pivotal for growth cone formation. In this study, we used conditioned neurons with high regenerative capacity to further dissect cytoskeletal mechanisms that might be involved in the gain of intrinsic axon growth capacity. Results Following a phospho-site broad signaling pathway screen, we found that in conditioned neurons with high regenerative capacity, decreased glycogen synthase kinase 3β (GSK3β) activity and increased microtubule growth speed in the growth cone were present. To investigate the importance of GSK3β regulation during axonal regeneration in vivo, we used three genetic mouse models with high, intermediate or no GSK3β activity in neurons. Following spinal cord injury, reduced GSK3β levels or complete neuronal deletion of GSK3β led to increased growth cone microtubule growth speed and promoted axon regeneration. While several microtubule-interacting proteins are GSK3β substrates, phospho-mimetic collapsin response mediator protein 2 (T/D-CRMP-2) was sufficient to decrease microtubule growth speed and neurite outgrowth of conditioned neurons and of GSK3β-depleted neurons, prevailing over the effect of decreased levels of phosphorylated microtubule-associated protein 1B (MAP1B) and through a mechanism unrelated to decreased levels of phosphorylated cytoplasmic linker associated protein 2 (CLASP2). In addition, phospho-resistant T/A-CRMP-2 counteracted the inhibitory myelin effect on neurite growth, further supporting the GSK3β-CRMP-2 relevance during axon regeneration. Conclusions Our work shows that increased microtubule growth speed in the growth cone is present in conditions of increased axonal growth, and is achieved following inactivation of the GSK3β-CRMP-2 pathway, enhancing axon regeneration through the glial scar. In this context, our results support that a precise control of microtubule dynamics, specifically in the growth cone, is required to optimize axon regrowth.
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Amelioration of β-amyloid-induced cognitive dysfunction and hippocampal axon degeneration by curcumin is associated with suppression of CRMP-2 hyperphosphorylation. Neurosci Lett 2013; 557 Pt B:112-7. [DOI: 10.1016/j.neulet.2013.10.024] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 10/10/2013] [Accepted: 10/11/2013] [Indexed: 01/08/2023]
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