1
|
Zhang Q, Li Y, Zhuo Y. Synaptic or Non-synaptic? Different Intercellular Interactions with Retinal Ganglion Cells in Optic Nerve Regeneration. Mol Neurobiol 2022; 59:3052-3072. [PMID: 35266115 PMCID: PMC9016027 DOI: 10.1007/s12035-022-02781-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 02/24/2022] [Indexed: 12/31/2022]
Abstract
Axons of adult neurons in the mammalian central nervous system generally fail to regenerate by themselves, and few if any therapeutic options exist to reverse this situation. Due to a weak intrinsic potential for axon growth and the presence of strong extrinsic inhibitors, retinal ganglion cells (RGCs) cannot regenerate their axons spontaneously after optic nerve injury and eventually undergo apoptosis, resulting in permanent visual dysfunction. Regarding the extracellular environment, research to date has generally focused on glial cells and inflammatory cells, while few studies have discussed the potentially significant role of interneurons that make direct connections with RGCs as part of the complex retinal circuitry. In this study, we provide a novel angle to summarize these extracellular influences following optic nerve injury as "intercellular interactions" with RGCs and classify these interactions as synaptic and non-synaptic. By discussing current knowledge of non-synaptic (glial cells and inflammatory cells) and synaptic (mostly amacrine cells and bipolar cells) interactions, we hope to accentuate the previously neglected but significant effects of pre-synaptic interneurons and bring unique insights into future pursuit of optic nerve regeneration and visual function recovery.
Collapse
Affiliation(s)
- Qi Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Yiqing Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China.
| | - Yehong Zhuo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, Guangzhou, 510060, China.
| |
Collapse
|
2
|
Yang M, Jian L, Fan W, Chen X, Zou H, Huang Y, Chen X, Zhou YG, Yuan R. Axon regeneration after optic nerve injury in rats can be improved via PirB knockdown in the retina. Cell Biosci 2021; 11:158. [PMID: 34380548 PMCID: PMC8359350 DOI: 10.1186/s13578-021-00670-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/25/2021] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND In the central nervous system (CNS), three types of myelin-associated inhibitors (MAIs) exert major inhibitory effects on nerve regeneration: Nogo-A, myelin-associated glycoprotein (MAG), and oligodendrocyte-myelin glycoprotein (OMgp). MAIs have two co-receptors, Nogo receptor (NgR) and paired immunoglobulin-like receptor B (PirB). Existing studies confirm that inhibiting NgR only exerted a modest disinhibitory effect in CNS. However, the inhibitory effects of PirB on nerve regeneration after binding to MAIs are controversial too. We aimed to further investigate the effect of PirB knockdown on the neuroprotection and axonal regeneration of retinal ganglion cells (RGCs) after optic nerve injury in rats. METHODS The differential expression of PirB in the retina was observed via immunofluorescence and western blotting after 1, 3, and 7 days of optic nerve injury (ONI). The retina was locally transfected with adeno-associated virus (AAV) PirB shRNA, then, the distribution of virus in tissues and cells was observed 21 days after AAV transfection to confirm the efficiency of PirB knockdown. Level of P-Stat3 and expressions of ciliary neurotrophic factor (CNTF) were detected via western blotting. RGCs were directly labeled with cholera toxin subunit B (CTB). The new axons of the optic nerve were specifically labeled with growth associated protein-43 (GAP43) via immunofluorescence. Flash visual evoked potential (FVEP) was used to detect the P1 and N1 latency, as well as N1-P1, P1-N2 amplitude to confirm visual function. RESULTS PirB expression in the retina was significantly increased after ONI. PirB knockdown was successful and significantly promoted P-Stat3 level and CNTF expression in the retina. PirB knockdown promoted the regeneration of optic nerve axons and improved the visual function indexes such as N1-P1 and P1-N2 amplitude. CONCLUSIONS PirB is one of the key molecules that inhibit the regeneration of the optic nerve, and inhibition of PirB has an excellent effect on promoting nerve regeneration, which allows the use of PirB as a target molecule to promote functional recovery after ONI.
Collapse
Affiliation(s)
- Mei Yang
- Department of Ophthalmology, Xinqiao Hospital, Army Medical University, 183 Xinqiao Zhengjie, Shapingba District, Chongqing, 400037, People's Republic of China
| | - Lan Jian
- Department of Ophthalmology, Xinqiao Hospital, Army Medical University, 183 Xinqiao Zhengjie, Shapingba District, Chongqing, 400037, People's Republic of China
| | - Wei Fan
- Department of Ophthalmology, Xinqiao Hospital, Army Medical University, 183 Xinqiao Zhengjie, Shapingba District, Chongqing, 400037, People's Republic of China
| | - Xing Chen
- The Molecular Biology Center, State Key Laboratory of Trauma, Burn and Combined Injury, Research Institute of Surgery and Daping Hospital, Army Medical University, 10 Changjiang Zhilu, Chongqing, 400042, People's Republic of China
| | - Huan Zou
- Department of Ophthalmology, Xinqiao Hospital, Army Medical University, 183 Xinqiao Zhengjie, Shapingba District, Chongqing, 400037, People's Republic of China
| | - Yanming Huang
- Department of Ophthalmology, Xinqiao Hospital, Army Medical University, 183 Xinqiao Zhengjie, Shapingba District, Chongqing, 400037, People's Republic of China
| | - Xiaofan Chen
- Department of Ophthalmology, Xinqiao Hospital, Army Medical University, 183 Xinqiao Zhengjie, Shapingba District, Chongqing, 400037, People's Republic of China
| | - Yuan-Guo Zhou
- The Molecular Biology Center, State Key Laboratory of Trauma, Burn and Combined Injury, Research Institute of Surgery and Daping Hospital, Army Medical University, 10 Changjiang Zhilu, Chongqing, 400042, People's Republic of China.
| | - Rongdi Yuan
- Department of Ophthalmology, Xinqiao Hospital, Army Medical University, 183 Xinqiao Zhengjie, Shapingba District, Chongqing, 400037, People's Republic of China.
| |
Collapse
|
3
|
Pradhan LK, Das SK. The Regulatory Role of Reticulons in Neurodegeneration: Insights Underpinning Therapeutic Potential for Neurodegenerative Diseases. Cell Mol Neurobiol 2021; 41:1157-1174. [PMID: 32504327 DOI: 10.1007/s10571-020-00893-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 05/29/2020] [Indexed: 02/06/2023]
Abstract
In the last few decades, cytoplasmic organellar dysfunction, such as that of the endoplasmic reticulum (ER), has created a new area of research interest towards the development of serious health maladies including neurodegenerative diseases. In this context, the extensively dispersed family of ER-localized proteins, i.e. reticulons (RTNs), is gaining interest because of its regulative control over neural regeneration. As most neurodegenerative diseases are pathologically manifested with the accretion of misfolded proteins with subsequent induction of ER stress, the regulatory role of RTNs in neural dysfunction cannot be ignored. With the limited information available in the literature, delineation of the functional connection between rising consequences of neurodegenerative diseases and RTNs need to be elucidated. In this review, we provide a broad overview on the recently revealed regulatory roles of reticulons in the pathophysiology of several health maladies, with special emphasis on neurodegeneration. Additionally, we have also recapitulated the decisive role of RTN4 in neurite regeneration and highlighted how neurodegeneration and proteinopathies are mechanistically linked with each other through specific RTN paralogues. With the recent findings advocating zebrafish Rtn4b (a mammalian Nogo-A homologue) downregulation following central nervous system (CNS) lesion, RTNs provides new insight into the CNS regeneration. However, there are controversies with respect to the role of Rtn4b in zebrafish CNS regeneration. Given these controversies, the connection between the unique regenerative capabilities of zebrafish CNS by distinct compensatory mechanisms and Rtn4b signalling pathway could shed light on the development of new therapeutic strategies against serious neurodegenerative diseases.
Collapse
Affiliation(s)
- Lilesh Kumar Pradhan
- Neurobiology Laboratory, Centre for Biotechnology, Siksha 'O' Anusandhan (Deemed To Be University), Kalinga Nagar, Bhubaneswar, 751003, India
| | - Saroj Kumar Das
- Neurobiology Laboratory, Centre for Biotechnology, School of Pharmaceutical Sciences, Siksha 'O' Anusandhan (Deemed To Be University), Kalinga Nagar, Bhubaneswar, 751003, India.
| |
Collapse
|
4
|
Holahan MR. A Shift from a Pivotal to Supporting Role for the Growth-Associated Protein (GAP-43) in the Coordination of Axonal Structural and Functional Plasticity. Front Cell Neurosci 2017; 11:266. [PMID: 28912688 PMCID: PMC5583208 DOI: 10.3389/fncel.2017.00266] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/18/2017] [Indexed: 11/14/2022] Open
Abstract
In a number of animal species, the growth-associated protein (GAP), GAP-43 (aka: F1, neuromodulin, B-50, G50, pp46), has been implicated in the regulation of presynaptic vesicular function and axonal growth and plasticity via its own biochemical properties and interactions with a number of other presynaptic proteins. Changes in the expression of GAP-43 mRNA or distribution of the protein coincide with axonal outgrowth as a consequence of neuronal damage and presynaptic rearrangement that would occur following instances of elevated patterned neural activity including memory formation and development. While functional enhancement in GAP-43 mRNA and/or protein activity has historically been hypothesized as a central mediator of axonal neuroplastic and regenerative responses in the central nervous system, it does not appear to be the crucial substrate sufficient for driving these responses. This review explores the historical discovery of GAP-43 (and associated monikers), its transcriptional, post-transcriptional and post-translational regulation and current understanding of protein interactions and regulation with respect to its role in axonal function. While GAP-43 itself appears to have moved from a pivotal to a supporting factor, there is no doubt that investigations into its functions have provided a clearer understanding of the biochemical underpinnings of axonal plasticity.
Collapse
|
5
|
Ramalingam M, Cheng MH, Kim SJ. Insulin suppresses MPP+-induced neurotoxicity by targeting integrins and syndecans in C6 astrocytes. J Recept Signal Transduct Res 2017; 37:550-559. [DOI: 10.1080/10799893.2017.1369119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Mahesh Ramalingam
- Department of Pharmacology and Toxicology, Metabolic Diseases Research Laboratory, School of Dentistry, Kyung Hee University, Seoul, South Korea
| | - Mi Hyun Cheng
- Department of Pharmacology and Toxicology, Metabolic Diseases Research Laboratory, School of Dentistry, Kyung Hee University, Seoul, South Korea
| | - Sung-Jin Kim
- Department of Pharmacology and Toxicology, Metabolic Diseases Research Laboratory, School of Dentistry, Kyung Hee University, Seoul, South Korea
| |
Collapse
|
6
|
Theis T, Yoo M, Park CS, Chen J, Kügler S, Gibbs KM, Schachner M. Lentiviral Delivery of miR-133b Improves Functional Recovery After Spinal Cord Injury in Mice. Mol Neurobiol 2017; 54:4659-4671. [PMID: 27412702 DOI: 10.1007/s12035-016-0007-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 06/05/2016] [Indexed: 02/05/2023]
Abstract
Based on the observation that microRNA (miRNA) 133b enhances regeneration after spinal cord injury in the adult zebrafish, we investigated whether this miRNA would be beneficial in a mammalian system in vitro and in vivo. We found that infection of cultured neurons with miR-133b promotes neurite outgrowth in vitro on an inhibitory substrate consisting of mixed chondroitin sulfate proteoglycans, when compared to infection with green fluorescent protein (GFP) for control. In vivo, viral infection of the injured adult mouse spinal cord at the time of injury at and in the vicinity of the lesion site enhanced expression of miR-133b. Measurements of locomotor recovery by Basso Mouse Scale (BMS) showed improvement of recovery starting at 4 weeks after injury and virus injection. This improvement was associated with downregulation of the expression levels of Ras homolog gene family member A (RhoA), chondroitin sulfate proteoglycans, and microglia/macrophage marker in the spinal cord as assayed 6 weeks after injury. Potential inhibitory molecules carrying consensus sequences for binding of miR-133b were identified in silico and verified in a reporter assay in vitro showing reductions in expression of RhoA, xylosyltransferase 1 (Xylt1), ephrin receptor A7 (Epha7), and purinergic receptor P2X ligand-gated ion channel 4 (P2RX4). These results encourage targeting miR-133 for therapy.
Collapse
Affiliation(s)
- Thomas Theis
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA
| | - Myung Yoo
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA
| | - Christopher S Park
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA
| | - Jian Chen
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA
| | - Sebastian Kügler
- Department of Neurology, Center Nanoscale Microscopy and Physiology of the Brain, University Medicine, Göttingen, Germany
| | - Kurt M Gibbs
- Morehead State University, Morehead, KY, 40351, USA
| | - Melitta Schachner
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA.
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany.
- Center for Neuroscience, Shantou University Medical College, 22 Xin Ling Road, Shantou, Guangdong, 515041, China.
| |
Collapse
|
7
|
Ramalingam M, Kim SJ. Insulin on activation of autophagy with integrins and syndecans against MPP +-induced α-synuclein neurotoxicity. Neurosci Lett 2016; 633:94-100. [PMID: 27646116 DOI: 10.1016/j.neulet.2016.09.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 07/18/2016] [Accepted: 09/15/2016] [Indexed: 01/14/2023]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease in the elderly caused by dopaminergic neuronal cell death. Human neuroblastoma SH-SY5Y cells differentiated by retinoic acid have been used to study the in vitro PD model induced by 1-methyl-4-phenyl pyridinium (MPP+). In this study, pretreatment of insulin inhibited MPP+-induced cell membrane damages, which also inhibited the Cox-2 and α-synuclein levels. In addition, MPP+ and/or insulin enhanced the autophagy LC3. Furthermore, MPP+-induced neurotoxicity diminished the integrins β3, αV and induced the syndecan-1 and -3. Insulin pretreatment enhanced the phosphorylation of integrin-linked kinase and further induced the integrin and syndecan molecules. These findings suggest that insulin prevents MPP+-induced α-synuclein apoptosis through the activation of integrin and syndecan pathways in SH-SY5Y+RA cells.
Collapse
Affiliation(s)
- Mahesh Ramalingam
- Department of Pharmacology and Toxicology, Metabolic Diseases Research Laboratory, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Sung-Jin Kim
- Department of Pharmacology and Toxicology, Metabolic Diseases Research Laboratory, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea.
| |
Collapse
|
8
|
Sui YP, Zhang XX, Lu JL, Sui F. New Insights into the Roles of Nogo-A in CNS Biology and Diseases. Neurochem Res 2015; 40:1767-85. [PMID: 26266872 DOI: 10.1007/s11064-015-1671-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/15/2015] [Accepted: 07/17/2015] [Indexed: 12/22/2022]
Abstract
Nogos have become a hot topic for its well-known number Nogo-A's big role in clinical matters. It has been recognized that the expression of Nogo-A and the receptor NgR1 inhibit the neuron's growth after CNS injuries or the onset of the MS. The piling evidence supports the notion that the Nogo-A is also involved in the synaptic plasticity, which was shown to negatively regulate the strength of synaptic transmission. The occurrence of significant schizophrenia-like behavioral phenotypes in Nogo-A KO rats also added strong proof to this conclusion. This review mainly focuses on the structure of Nogo-A and its corresponding receptor-NgR1, its intra- and extra-cellular signaling, together with its major physiological functions such as regulation of migration and distribution and its related diseases like stroke, AD, ALS and so on.
Collapse
Affiliation(s)
- Yun-Peng Sui
- Institute of Chinese Material Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | | | | | | |
Collapse
|
9
|
Zhai P, Chen XB, Schreyer DJ. An in vitro study of peptide-loaded alginate nanospheres for antagonizing the inhibitory effect of Nogo-A protein on axonal growth. ACTA ACUST UNITED AC 2015; 10:045016. [PMID: 26238410 DOI: 10.1088/1748-6041/10/4/045016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The adult mammalian central nervous system has limited ability to regenerate after injury. This is due, in part, to the presence of myelin-associated axon growth inhibitory proteins such as Nogo-A that bind and activate the Nogo receptor, leading to profound inhibition of actin-based motility within the growing axon tip. This paper presents an in vitro study of the use of a Nogo receptor-blocking peptide to antagonize the inhibitory effect of Nogo-A on axon growth. Alginate nanospheres were fabricated using an emulsion technique and loaded with Nogo receptor-blocking peptide, or with other model proteins. Protein release profiles were studied, and retention of the bioactivity of released proteins was verified. Primary dorsal root ganglion neurons were cultured and their ability to grow neurites was challenged with Nogo-A chimeric protein in the absence or presence of Nogo receptor antagonist peptide-loaded alginate nanospheres. Our results demonstrate that peptide released from alginate nanospheres could overcome the growth inhibitory effect of Nogo-A, suggesting that a similar peptide delivery strategy using alginate nanospheres might be used to improve axon regeneration within the injured central nervous system.
Collapse
Affiliation(s)
- Peng Zhai
- Division of Biomedical Engineering, University of Saskatchewan, Saskatoon SK S7N 5A9, Canada
| | | | | |
Collapse
|
10
|
Cui Z, Kang J, Hu D, Zhou J, Wang Y. Oncomodulin/truncated protamine-mediated Nogo-66 receptor small interference RNA delivery promotes axon regeneration in retinal ganglion cells. Mol Cells 2014; 37:613-9. [PMID: 25134537 PMCID: PMC4145373 DOI: 10.14348/molcells.2014.0155] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 07/06/2014] [Accepted: 07/07/2014] [Indexed: 01/24/2023] Open
Abstract
The optic nerve often suffers regenerative failure after injury, leading to serious visual impairment such as glaucoma. The main inhibitory factors, including Nogo-A, oligodendrocyte myelin glycoprotein, and myelin-associated glycoprotein, exert their inhibitory effects on axonal growth through the same receptor, the Nogo-66 receptor (NgR). Oncomodulin (OM), a calcium-binding protein with a molecular weight of an ∼12 kDa, which is secreted from activated macrophages, has been demonstrated to have high and specific affinity for retinal ganglion cells (RGC) and promote greater axonal regeneration than other known polypeptide growth factors. Protamine has been reported to effectively deliver small interference RNA (siRNA) into cells. Accordingly, a fusion protein of OM and truncated protamine (tp) may be used as a vehicle for the delivery of NgR siRNA into RGC for gene therapy. To test this hypothesis, we constructed OM and tp fusion protein (OM/tp) expression vectors. Using the indirect immunofluorescence labeling method, OM/tp fusion proteins were found to have a high affinity for RGC. The gel shift assay showed that the OM/tp fusion proteins retained the capacity to bind to DNA. Using OM/tp fusion proteins as a delivery tool, the siRNA of NgR was effectively transfected into cells and significantly down-regulated NgR expression levels. More importantly, OM/tp-NgR siRNA dramatically promoted axonal growth of RGC compared with the application of OM/tp recombinant protein or NgR siRNA alone in vitro. In addition, OM/tp-NgR siRNA highly elevated intracellular cyclic adenosine monophosphate (cAMP) levels and inhibited activation of the Ras homolog gene family, member A (RhoA). Taken together, our data demonstrated that the recombinant OM/tp fusion proteins retained the functions of both OM and tp, and that OM/tp-NgR siRNA might potentially be used for the treatment of optic nerve injury.
Collapse
Affiliation(s)
- Zhili Cui
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an710032,
China
| | | | - Dan Hu
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an710032,
China
| | - Jian Zhou
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an710032,
China
| | - Yusheng Wang
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an710032,
China
| |
Collapse
|
11
|
Roloff F, Ziege S, Baumgärtner W, Wewetzer K, Bicker G. Schwann cell-free adult canine olfactory ensheathing cell preparations from olfactory bulb and mucosa display differential migratory and neurite growth-promoting properties in vitro. BMC Neurosci 2013; 14:141. [PMID: 24219805 PMCID: PMC3840578 DOI: 10.1186/1471-2202-14-141] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 11/07/2013] [Indexed: 12/04/2022] Open
Abstract
Background Transplantation of olfactory ensheathing cells (OEC) and Schwann cells (SC) is a promising therapeutic strategy to promote axonal growth and remyelination after spinal cord injury. Previous studies mainly focused on the rat model though results from primate and porcine models differed from those in the rat model. Interestingly, canine OECs show primate-like in vitro characteristics, such as absence of early senescence and abundance of stable p75NTR expression indicating that this species represents a valuable translational species for further studies. So far, few investigations have tested different glial cell types within the same study under identical conditions. This makes it very difficult to evaluate contradictory or confirmatory findings reported in various studies. Moreover, potential contamination of OEC preparations with Schwann cells was difficult to exclude. Thus, it remains rather controversial whether the different glial types display distinct cellular properties. Results Here, we established cultures of Schwann cell-free OECs from olfactory bulb (OB-OECs) and mucosa (OM-OECs) and compared them in assays to Schwann cells. These glial cultures were obtained from a canine large animal model and used for monitoring migration, phagocytosis and the effects on in vitro neurite growth. OB-OECs and Schwann cells migrated faster than OM-OECs in a scratch wound assay. Glial cell migration was not modulated by cGMP and cAMP signaling, but activating protein kinase C enhanced motility. All three glial cell types displayed phagocytic activity in a microbead assay. In co-cultures with of human model (NT2) neurons neurite growth was maximal on OB-OECs. Conclusions These data provide evidence that OB- and OM-OECs display distinct migratory behavior and interaction with neurites. OB-OECs migrate faster and enhance neurite growth of human model neurons better than Schwann cells, suggesting distinct and inherent properties of these closely-related cell types. Future studies will have to address whether, and how, these cellular properties correlate with the in vivo behavior after transplantation.
Collapse
Affiliation(s)
| | | | | | | | - Gerd Bicker
- Division of Cell Biology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173 Hannover, Germany.
| |
Collapse
|