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Pottorf TS, Rotterman TM, McCallum WM, Haley-Johnson ZA, Alvarez FJ. The Role of Microglia in Neuroinflammation of the Spinal Cord after Peripheral Nerve Injury. Cells 2022; 11:cells11132083. [PMID: 35805167 PMCID: PMC9265514 DOI: 10.3390/cells11132083] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 06/26/2022] [Accepted: 06/27/2022] [Indexed: 12/12/2022] Open
Abstract
Peripheral nerve injuries induce a pronounced immune reaction within the spinal cord, largely governed by microglia activation in both the dorsal and ventral horns. The mechanisms of activation and response of microglia are diverse depending on the location within the spinal cord, type, severity, and proximity of injury, as well as the age and species of the organism. Thanks to recent advancements in neuro-immune research techniques, such as single-cell transcriptomics, novel genetic mouse models, and live imaging, a vast amount of literature has come to light regarding the mechanisms of microglial activation and alluding to the function of microgliosis around injured motoneurons and sensory afferents. Herein, we provide a comparative analysis of the dorsal and ventral horns in relation to mechanisms of microglia activation (CSF1, DAP12, CCR2, Fractalkine signaling, Toll-like receptors, and purinergic signaling), and functionality in neuroprotection, degeneration, regeneration, synaptic plasticity, and spinal circuit reorganization following peripheral nerve injury. This review aims to shed new light on unsettled controversies regarding the diversity of spinal microglial-neuronal interactions following injury.
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Affiliation(s)
- Tana S. Pottorf
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; (T.S.P.); (W.M.M.); (Z.A.H.-J.)
| | - Travis M. Rotterman
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30318, USA;
| | - William M. McCallum
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; (T.S.P.); (W.M.M.); (Z.A.H.-J.)
| | - Zoë A. Haley-Johnson
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; (T.S.P.); (W.M.M.); (Z.A.H.-J.)
| | - Francisco J. Alvarez
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; (T.S.P.); (W.M.M.); (Z.A.H.-J.)
- Correspondence:
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Yoo MC, Chon J, Jung J, Kim SS, Bae S, Kim SH, Yeo SG. Potential Therapeutic Strategies and Substances for Facial Nerve Regeneration Based on Preclinical Studies. Int J Mol Sci 2021; 22:ijms22094926. [PMID: 34066483 PMCID: PMC8124575 DOI: 10.3390/ijms22094926] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/23/2021] [Accepted: 04/27/2021] [Indexed: 12/14/2022] Open
Abstract
Despite advances in microsurgical technology and an improved understanding of nerve regeneration, obtaining satisfactory results after facial nerve injury remains a difficult clinical problem. Among existing peripheral nerve regeneration studies, relatively few have focused on the facial nerve, particularly how experimental studies of the facial nerve using animal models play an essential role in understanding functional outcomes and how such studies can lead to improved axon regeneration after nerve injury. The purpose of this article is to review current perspectives on strategies for applying potential therapeutic methods for facial nerve regeneration. To this end, we searched Embase, PubMed, and the Cochrane library using keywords, and after applying exclusion criteria, obtained a total of 31 qualifying experimental studies. We then summarize the fundamental experimental studies on facial nerve regeneration, highlighting recent bioengineering studies employing various strategies for supporting facial nerve regeneration, including nerve conduits with stem cells, neurotrophic factors, and/or other therapeutics. Our summary of the methods and results of these previous reports reveal a common feature among studies, showing that various neurotrophic factors arising from injured nerves contribute to a microenvironment that plays an important role in functional recovery. In most cases, histological examinations showed that this microenvironmental influence increased axonal diameter as well as myelination thickness. Such an analysis of available research on facial nerve injury and regeneration represents the first step toward future therapeutic strategies.
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Affiliation(s)
- Myung Chul Yoo
- Department of Physical Medicine & Rehabilitation, College of Medicine, Kyung Hee University, Seoul 02447, Korea; (M.C.Y.); (J.C.)
| | - Jinmann Chon
- Department of Physical Medicine & Rehabilitation, College of Medicine, Kyung Hee University, Seoul 02447, Korea; (M.C.Y.); (J.C.)
| | - Junyang Jung
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, Seoul 02447, Korea;
| | - Sung Su Kim
- Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, Seoul 02447, Korea;
| | - Seonhwan Bae
- Department of Otorhinolaryngology, Head & Neck Surgery, College of Medicine, Kyung Hee University, Seoul 02447, Korea; (S.B.); (S.H.K.)
| | - Sang Hoon Kim
- Department of Otorhinolaryngology, Head & Neck Surgery, College of Medicine, Kyung Hee University, Seoul 02447, Korea; (S.B.); (S.H.K.)
| | - Seung Geun Yeo
- Department of Otorhinolaryngology, Head & Neck Surgery, College of Medicine, Kyung Hee University, Seoul 02447, Korea; (S.B.); (S.H.K.)
- Correspondence: ; Tel.: +82-2-958-8980; Fax: +82-2-958-8470
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Ruven C, Badea SR, Wong WM, Wu W. Combination Treatment With Exogenous GDNF and Fetal Spinal Cord Cells Results in Better Motoneuron Survival and Functional Recovery After Avulsion Injury With Delayed Root Reimplantation. J Neuropathol Exp Neurol 2019; 77:325-343. [PMID: 29420729 DOI: 10.1093/jnen/nly009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
When spinal roots are torn off from the spinal cord, both the peripheral and central nervous system get damaged. As the motoneurons lose their axons, they start to die rapidly, whereas target muscles atrophy due to the denervation. In this kind of complicated injury, different processes need to be targeted in the search for the best treatment strategy. In this study, we tested glial cell-derived neurotrophic factor (GDNF) treatment and fetal lumbar cell transplantation for their effectiveness to prevent motoneuron death and muscle atrophy after the spinal root avulsion and delayed reimplantation. Application of exogenous GDNF to injured spinal cord greatly prevented the motoneuron death and enhanced the regeneration and axonal sprouting, whereas no effect was seen on the functional recovery. In contrast, cell transplantation into the distal nerve did not affect the host motoneurons but instead mitigated the muscle atrophy. The combination of GDNF and cell graft reunited the positive effects resulting in better functional recovery and could therefore be considered as a promising strategy for nerve and spinal cord injuries that involve the avulsion of spinal roots.
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Affiliation(s)
- Carolin Ruven
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | | | - Wai-Man Wong
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Wutian Wu
- School of Biomedical Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.,State Key Laboratory of Brain and Cognitive Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.,GHM Institute of CNS Regeneration, Jinan University, Guangzhou, China.,Re-Stem Biotechnology Co., Ltd, Jiangsu, China
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Zhang L, Fan Z, Han Y, Xu L, Liu W, Bai X, Zhou M, Li J, Wang H. Valproic Acid Promotes Survival of Facial Motor Neurons in Adult Rats After Facial Nerve Transection: a Pilot Study. J Mol Neurosci 2018. [PMID: 29532368 DOI: 10.1007/s12031-018-1051-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Valproic acid (VPA), a medication primarily used to treat epilepsy and bipolar disorder, has been applied to the repair of central and peripheral nervous system injury. The present study investigated the effect of VPA on functional recovery, survival of facial motor neurons (FMNs), and expression of proteins in rats after facial nerve trunk transection by functional measurement, Nissl staining, TUNEL, immunofluorescence, and Western blot. Following facial nerve injury, all rats in group VPA showed a better functional recovery, which was significant at the given time, compared with group NS. The Nissl staining results demonstrated that the number of FMNs survival in group VPA was higher than that in group normal saline (NS). TUNEL staining showed that axonal injury of facial nerve could lead to neuronal apoptosis of FMNs. But treatment of VPA significantly reduced cell apoptosis by decreasing the expression of Bax protein and increased neuronal survival by upregulating the level of brain-derived neurotrophic factor (BDNF) and growth associated protein-43 (GAP-43) expression in injured FMNs compared with group NS. Overall, our findings suggest that VPA may advance functional recovery, reduce lesion-induced apoptosis, and promote neuron survival after facial nerve transection in rats. This study provides an experimental evidence for better understanding the mechanism of injury and repair of peripheral facial paralysis.
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Affiliation(s)
- Lili Zhang
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, China
- Department of Otolaryngology-Head and Neck Surgery, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, 264199, China
| | - Zhaomin Fan
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, China
| | - Yuechen Han
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, China
| | - Lei Xu
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, China
| | - Wenwen Liu
- Shandong Provincial Key Laboratory of Otology, Jinan, 250022, China
| | - Xiaohui Bai
- Shandong Provincial Key Laboratory of Otology, Jinan, 250022, China
| | - Meijuan Zhou
- Shandong Provincial Key Laboratory of Otology, Jinan, 250022, China
| | - Jianfeng Li
- Shandong Provincial Key Laboratory of Otology, Jinan, 250022, China
- Institute of Eye and ENT, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250022, China
| | - Haibo Wang
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250021, China.
- Shandong Provincial Key Laboratory of Otology, Jinan, 250022, China.
- Institute of Eye and ENT, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, 250022, China.
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Lyu C, Lyu GW, Martinez A, Shi TJS. Effect of nerve injury on the number of dorsal root ganglion neurons and autotomy behavior in adult Bax-deficient mice. J Pain Res 2017; 10:2079-2087. [PMID: 28919807 PMCID: PMC5587150 DOI: 10.2147/jpr.s133087] [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] [Indexed: 01/14/2023] Open
Abstract
Background The proapoptotic molecule BAX, plays an important role in mitochondrial apoptotic pathway. Dorsal root ganglion (DRG) neurons depend on neurotrophic factors for survival at early developmental stages. Withdrawal of neurotrophic factors will induce apoptosis in DRG neurons, but this type of cell death can be delayed or prevented in neonatal Bax knockout (KO) mice. In adult animals, evidence also shows that DRG neurons are less dependent upon neurotrophic factors for survival. However, little is known about the effect of Bax deletion on the survival of normal and denervated DRG neurons in adult mice. Methods A unilateral sciatic nerve transection was performed in adult Bax KO mice and wild-type (WT) littermates. Stereological method was employed to quantify the number of lumbar-5 DRG neurons 1 month post-surgery. Nerve injury-induced autotomy behavior was also examined on days 1, 3, and 7 post-surgery. Results There were significantly more neurons in contralateral DRGs of KO mice as compared with WT mice. The number of neurons was reduced in ipsilateral DRGs in both KO and WT mice. No changes in size distributions of DRG neuron profiles were detected before or after nerve injury. Injury-induced autotomy behavior developed much earlier and was more serious in KO mice. Conclusion Although postnatal death or loss of DRG neurons is partially prevented by Bax deletion, this effect cannot interfere with long-term nerve injury-induced neuronal loss. The exaggerated self-amputation behavior observed in the mutant mice indicates that Bax deficiency may enhance the development of spontaneous pain following nerve injury.
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Affiliation(s)
- Chuang Lyu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.,Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Gong-Wei Lyu
- Department of Neurology, 1st Hospital of Harbin Medical University, Harbin, People's Republic of China
| | - Aurora Martinez
- Department of Biomedicine, University of Bergen, Bergen, Norway
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Zhang Y, Zhang R, Qiao S, Fan J. Effect of FK506 on apoptosis of facial motor neurons in rats and its possible mechanism. Eur Arch Otorhinolaryngol 2015; 273:601-6. [PMID: 25784181 DOI: 10.1007/s00405-015-3591-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 02/28/2015] [Indexed: 01/06/2023]
Abstract
To investigate the effect of FK506 on apoptosis of facial motor neurons in rats and its possible mechanism. A total of 48 Wistar rats were randomly divided into experimental group and control group. Facial nerve injury model was established by transection of facial nerve at stylomastoid foramen. Rats in experimental group and control group were provided with FK506 and normal saline by intraperitoneal injection, respectively. The morphology of facial neurons was observed under light microscope at different time points after injury. Apoptotic facial motor neurons were detected by TdT-mediated dUTP-biotin nick and labeling (TUNEL) staining, and expression of bcl-2 and bax was evaluated by immunohistochemistry. After facial nerve transection, the apoptotic cells in experimental group significantly decreased compared to control group (P < 0.05), with higher expression of bcl-2 and lower expression of bax in experimental group. FK506 could inhibit apoptosis of facial motor neurons after facial nerve transection, possibly via up-regulation of bcl-2 expression and down-regulation of bax expression.
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Affiliation(s)
- Ying Zhang
- Neuroscience Care Unit, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, People's Republic of China.
| | - Ruoyu Zhang
- Department of Geriatrics, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Song Qiao
- Department of Neurology, Zhejiang Hospital, Hangzhou, People's Republic of China
| | - Jing Fan
- Neuroscience Care Unit, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, 310009, People's Republic of China
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Casas C, Isus L, Herrando-Grabulosa M, Mancuso FM, Borrás E, Sabidó E, Forés J, Aloy P. Network-based proteomic approaches reveal the neurodegenerative, neuroprotective and pain-related mechanisms involved after retrograde axonal damage. Sci Rep 2015; 5:9185. [PMID: 25784190 PMCID: PMC5378195 DOI: 10.1038/srep09185] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 02/05/2015] [Indexed: 12/14/2022] Open
Abstract
Neurodegenerative processes are preceded by neuronal dysfunction and synaptic disconnection. Disconnection between spinal motoneuron (MN) soma and synaptic target leads either to a retrograde degenerative process or to a regenerative reaction, depending injury proximity among other factors. Distinguished key events associated with one or other processes may give some clues towards new therapeutical approaches based on boosting endogenous neuroprotective mechanisms. Root mechanical traction leads to retrograde MN degeneration, but share common initial molecular mechanisms with a regenerative process triggered by distal axotomy and suture. By 7 days post-injury, key molecular events starts to diverge and sign apart each destiny. We used comparative unbiased proteomics to define these signatures, coupled to a novel network-based analysis to get biological meaning. The procedure implicated the previous generation of combined topological information from manual curated 19 associated biological processes to be contrasted with the proteomic list using gene enrichment analysis tools. The novel and unexpected results suggested that motoneurodegeneration is better explained mainly by the concomitant triggering of anoikis, anti-apoptotic and neuropathic-pain related programs. In contrast, the endogenous neuroprotective mechanisms engaged after distal axotomy included specifically rather anti-anoikis and selective autophagy. Validated protein-nodes and processes are highlighted across discussion.
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Affiliation(s)
- Caty Casas
- Group of Neuroplasticity and Regeneration, Institut de Neurociències and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 08193 Bellaterra, Barcelona, Spain
| | - Laura Isus
- Joint IRB-BSC-CRG Program in Computational Biology. Institute for Research in Biomedicine (IRB Barcelona), 08028 Barcelona, Catalonia, Spain
| | - Mireia Herrando-Grabulosa
- Group of Neuroplasticity and Regeneration, Institut de Neurociències and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 08193 Bellaterra, Barcelona, Spain
| | - Francesco M. Mancuso
- Proteomic Unit, Centre for Genomic Regulation (CRG) and UPF, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Eva Borrás
- Proteomic Unit, Centre for Genomic Regulation (CRG) and UPF, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Eduardo Sabidó
- Proteomic Unit, Centre for Genomic Regulation (CRG) and UPF, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Joaquim Forés
- Hand and Peripheral Nerve Unit, Hospital Clínic i Provincial, Universitat de Barcelona, Barcelona, Spain
| | - Patrick Aloy
- Joint IRB-BSC-CRG Program in Computational Biology. Institute for Research in Biomedicine (IRB Barcelona), 08028 Barcelona, Catalonia, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Catalonia, Spain
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9
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Wang H, Fang F, Yi J, Xiang Z, Sun M, Jiang H. Establishment and assessment of the perinatal mouse facial nerve axotomy model via a subauricular incision approach. Exp Biol Med (Maywood) 2012; 237:1249-55. [PMID: 23239435 DOI: 10.1258/ebm.2012.012134] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A reliable animal model of facial nerve (FN) injury forms the basis for effective scientific studies of injury and repair of the FN. Currently, rodents are the most widely used animal model for such studies, most of which adopt a postauricular incision approach. However, it is difficult to carry out the procedure on perinatal rodents owing to characteristics of anatomy and the direction of incision. Based on anatomical studies on the extracranial segment of the FN in mice, we established a FN axotomy model by using a subauricular incision (SI) approach. The effect and the outcome of the FN transection were evaluated by electrophysiology, behavioral assessment and histological observation in 20 healthy four-week-old BALB/c mice. Favorable results were obtained in all of the mice and none died during the operation or subsequent observation period. Compared with the classic postauricular incision approach, the SI approach possesses multiple advantages including easier access, more satisfactory exposure of the FN trunk, minimal invasion and providing a larger operation field, which would be critical for those studies on the rodent in early development or delicate surgical manipulations.
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Affiliation(s)
- Hui Wang
- Department of Plastic Surgery, Neuroscience Research Center, Chang Zheng Hospital, The Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Fan Fang
- Department of Plastic Surgery, Neuroscience Research Center, Chang Zheng Hospital, The Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Jing Yi
- Department of Plastic Surgery, Neuroscience Research Center, Chang Zheng Hospital, The Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Zhenghua Xiang
- Department of Plastic Surgery, Neuroscience Research Center, Chang Zheng Hospital, The Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Meiqing Sun
- Department of Plastic Surgery, Neuroscience Research Center, Chang Zheng Hospital, The Second Military Medical University, Shanghai 200433, People's Republic of China
| | - Hua Jiang
- Department of Plastic Surgery, Neuroscience Research Center, Chang Zheng Hospital, The Second Military Medical University, Shanghai 200433, People's Republic of China
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Cho B, Choi SY, Park OH, Sun W, Geum D. Differential expression of BNIP family members of BH3-only proteins during the development and after axotomy in the rat. Mol Cells 2012; 33:605-10. [PMID: 22639046 PMCID: PMC3887754 DOI: 10.1007/s10059-012-0051-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 04/03/2012] [Accepted: 04/20/2012] [Indexed: 10/28/2022] Open
Abstract
The BNIPs (BCL2 and adenovirus E1B 19 kDa interacting proteins) are a subfamily of BCL2 family proteins typically containing a single BCL2 homology 3 (BH3) domain. BNIPs exert important roles in two major degradation processes in cells - apoptosis and autophagy. Although it is known that the function of BNIPs is transcriptionally regulated under hypoxic conditions in tumors, their regulation in the developing brain and neurons following the induction of apoptosis/autophagy is largely unknown. In this study, we demonstrate that three members of the BNIP family, BNIP1, BNIP3 and BNIP3L, are expressed in the developing brain with distinct brain region specificity. BNIP3 mRNA was especially enriched in the entorhinal cortex, raising a possibility that it may have additional biological functions in addition to its apoptotic and autophagic functions. Following starvation-induced autophagy induction, BNIP1 mRNA was selectively increased in cultured neurons. However, the apoptogenic chemical staurosporine failed to modulate the expression of BNIPs, which is in contrast to the marked induction of all BNIPs by glucose-oxygen deprivation. Finally, neonatal nerve axotomy, which triggers apoptosis in motoneurons, selectively enhanced BNIP3 mRNA expression. Collectively, these results suggest that the expression of BNIPs is differentially regulated depending on the stimuli, and BNIPs may exert unique biological functions.
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Affiliation(s)
- Bongki Cho
- Department of Anatomy, College of Medicine, Korea University, Seoul 136-705,
Korea
| | - So Yoen Choi
- Department of Anatomy, College of Medicine, Korea University, Seoul 136-705,
Korea
| | | | - Woong Sun
- Department of Anatomy, College of Medicine, Korea University, Seoul 136-705,
Korea
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Dissociation of progressive dopaminergic neuronal death and behavioral impairments by Bax deletion in a mouse model of Parkinson's diseases. PLoS One 2011; 6:e25346. [PMID: 22043283 PMCID: PMC3197195 DOI: 10.1371/journal.pone.0025346] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 09/01/2011] [Indexed: 11/19/2022] Open
Abstract
Parkinson's disease (PD) is a common, late-onset movement disorder with selective degeneration of dopaminergic (DA) neurons in the substantia nigra (SN). Although the neurotoxin 6-hydroxydopamine (6-OHDA) has been used to induce progressive degeneration of DA neurons in various animal models of PD, the precise molecular pathway and the impact of anti-apoptotic treatment on this neurodegeneration are less understood. Following a striatal injection of 6-OHDA, we observed atrophy and progressive death of DA neurons in wild-type mice. These degenerating DA neurons never exhibited signs of apoptosis (i.e., caspase-3 activation and cytoplasmic release of cytochrome C), but rather show nuclear translocation of apoptosis-inducing factor (AIF), a hallmark of regulated necrosis. However, mice with genetic deletion of the proapoptotic gene Bax (Bax-KO) exhibited a complete absence of 6-OHDA-induced DA neuron death and nuclear translocation of AIF, indicating that 6-OHDA-induced DA neuronal death is mediated by Bax-dependent AIF activation. On the other hand, DA neurons that survived in Bax-KO mice exhibited marked neuronal atrophy, without significant improvement of PD-related behavioral deficits. These findings suggest that anti-apoptotic therapy may not be sufficient for PD treatment, and the prevention of Bax-independent neuronal atrophy may be an important therapeutic target.
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12
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Penas C, Font-Nieves M, Forés J, Petegnief V, Planas A, Navarro X, Casas C. Autophagy, and BiP level decrease are early key events in retrograde degeneration of motoneurons. Cell Death Differ 2011; 18:1617-27. [PMID: 21436843 PMCID: PMC3172115 DOI: 10.1038/cdd.2011.24] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 02/09/2011] [Accepted: 02/10/2011] [Indexed: 12/11/2022] Open
Abstract
Disconnection of the axon from the soma of spinal motoneurons (MNs) leads either to a retrograde degenerative process or to a regenerative reaction, depending on the severity and the proximity to the soma of the axonal lesion. The endoplasmic reticulum (ER) is a continuous membranous network that extends from the nucleus to the entire cytoplasm of the neuronal soma, axon and dendrites. We investigated whether axonal injury is sensed by the ER and triggers the activation of protective mechanisms, such as the unfolded protein response (UPR) and autophagy. We found early (at 3 days) accumulation of beclin1, LC3II and Lamp-1, hallmarks of autophagy, in both degenerating MNs after spinal root avulsion and in non-degenerating MNs after distal nerve section, although Lamp-1 disappeared by 5 days only in the former. In contrast, only degenerating MNs presented early activation of IRE1α, revealed by an increase of the spliced isoform of Xbp1 and accumulation of ATF4 in their nucleus, two branches of the UPR, and late BiP downregulation in association with cytoskeletal and organelle disorganization. We conclude that BiP decrease is a signature of the degenerating process, as its overexpression led to an increase in MN survival after root avulsion. Besides, Bcl2 is strongly implicated in the survival pathway activated by BiP overexpression.
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Affiliation(s)
- C Penas
- Group of Neuroplasticity and Regeneration, Institute of Neurosciences, Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - M Font-Nieves
- Department of Brain Ischemia and Neurodegeneration, Institute for Biomedical Research of Barcelona (IIBB), Spanish Research Council (CSIC), Institut d'Investigacions Biomèdiques August Pi Sunyer (IDIBAPS), Barcelona, Spain
| | - J Forés
- Hand and Peripheral Nerve Unit, Hospital Clínic i Provincial, Universitat de Barcelona, Barcelona, Spain
| | - V Petegnief
- Department of Brain Ischemia and Neurodegeneration, Institute for Biomedical Research of Barcelona (IIBB), Spanish Research Council (CSIC), Institut d'Investigacions Biomèdiques August Pi Sunyer (IDIBAPS), Barcelona, Spain
| | - A Planas
- Department of Brain Ischemia and Neurodegeneration, Institute for Biomedical Research of Barcelona (IIBB), Spanish Research Council (CSIC), Institut d'Investigacions Biomèdiques August Pi Sunyer (IDIBAPS), Barcelona, Spain
| | - X Navarro
- Group of Neuroplasticity and Regeneration, Institute of Neurosciences, Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - C Casas
- Group of Neuroplasticity and Regeneration, Institute of Neurosciences, Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
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13
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Gould TW, Oppenheim RW. Motor neuron trophic factors: therapeutic use in ALS? BRAIN RESEARCH REVIEWS 2011; 67:1-39. [PMID: 20971133 PMCID: PMC3109102 DOI: 10.1016/j.brainresrev.2010.10.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2010] [Revised: 10/12/2010] [Accepted: 10/18/2010] [Indexed: 12/12/2022]
Abstract
The modest effects of neurotrophic factor (NTF) treatment on lifespan in both animal models and clinical studies of Amyotropic Lateral Sclerosis (ALS) may result from any one or combination of the four following explanations: 1.) NTFs block cell death in some physiological contexts but not in ALS; 2.) NTFs do not rescue motoneurons (MNs) from death in any physiological context; 3.) NTFs block cell death in ALS but to no avail; and 4.) NTFs are physiologically effective but limited by pharmacokinetic constraints. The object of this review is to critically evaluate the role of both NTFs and the intracellular cell death pathway itself in regulating the survival of spinal and cranial (lower) MNs during development, after injury and in response to disease. Because the role of molecules mediating MN survival has been most clearly resolved by the in vivo analysis of genetically engineered mice, this review will focus on studies of such mice expressing reporter, null or other mutant alleles of NTFs, NTF receptors, cell death or ALS-associated genes.
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Affiliation(s)
- Thomas W Gould
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1010, USA.
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The proapoptotic Bcl-2 protein Bax plays an important role in the pathogenesis of reovirus encephalitis. J Virol 2011; 85:3858-71. [PMID: 21307199 DOI: 10.1128/jvi.01958-10] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Encephalitis induced by reovirus serotype 3 (T3) strains results from the apoptotic death of infected neurons. Extrinsic apoptotic signaling is activated in reovirus-infected neurons in vitro and in vivo, but the role of intrinsic apoptosis signaling during encephalitis is largely unknown. Bax plays a key role in intrinsic apoptotic signaling in neurons by allowing the release of mitochondrial cytochrome c. We found Bax activation and cytochrome c release in neurons following infection of neonatal mice with T3 reoviruses. Bax(-/-) mice infected with T3 Abney (T3A) have reduced central nervous system (CNS) tissue injury and decreased apoptosis, despite viral replication that is similar to that in wild-type (WT) Bax(+/+) mice. In contrast, in the heart, T3A-infected Bax(-/-) mice have viral growth, caspase activation, and injury comparable to those in WT mice, indicating that the role of Bax in pathogenesis is organ specific. Nonmyocarditic T3 Dearing (T3D)-infected Bax(-/-) mice had delayed disease and enhanced survival compared to WT mice. T3D-infected Bax(-/-) mice had significantly lower viral titers and levels of activated caspase 3 in the brain despite unaffected transneuronal spread of virus. Cytochrome c and Smac release occurred in some reovirus-infected neurons in the absence of Bax; however, this was clearly reduced compared to levels seen in Bax(+/+) wild-type mice, indicating that Bax is necessary for efficient activation of proapoptotic mitochondrial signaling in infected neurons. Our studies suggest that Bax is important for reovirus growth and pathogenesis in neurons and that the intrinsic pathway of apoptosis, mediated by Bax, is important for full expression of disease, CNS tissue injury, apoptosis, and viral growth in the CNS of reovirus-infected mice.
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