1
|
Wu W, Nguyen T, Ordaz JD, Zhang Y, Liu NK, Hu X, Liu Y, Ping X, Han Q, Wu X, Qu W, Gao S, Shields CB, Jin X, Xu XM. Transhemispheric cortex remodeling promotes forelimb recovery after spinal cord injury. JCI Insight 2022; 7:e158150. [PMID: 35552276 PMCID: PMC9309060 DOI: 10.1172/jci.insight.158150] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 05/10/2022] [Indexed: 11/28/2022] Open
Abstract
Understanding the reorganization of neural circuits spared after spinal cord injury in the motor cortex and spinal cord would provide insights for developing therapeutics. Using optogenetic mapping, we demonstrated a transhemispheric recruitment of neural circuits in the contralateral cortical M1/M2 area to improve the impaired forelimb function after a cervical 5 right-sided hemisection in mice, a model mimicking the human Brown-Séquard syndrome. This cortical reorganization can be elicited by a selective cortical optogenetic neuromodulation paradigm. Areas of whisker, jaw, and neck, together with the rostral forelimb area, on the motor cortex ipsilateral to the lesion were engaged to control the ipsilesional forelimb in both stimulation and nonstimulation groups 8 weeks following injury. However, significant functional benefits were only seen in the stimulation group. Using anterograde tracing, we further revealed a robust sprouting of the intact corticospinal tract in the spinal cord of those animals receiving optogenetic stimulation. The intraspinal corticospinal axonal sprouting correlated with the forelimb functional recovery. Thus, specific neuromodulation of the cortical neural circuits induced massive neural reorganization both in the motor cortex and spinal cord, constructing an alternative motor pathway in restoring impaired forelimb function.
Collapse
Affiliation(s)
- Wei Wu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Tyler Nguyen
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Josue D. Ordaz
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Yiping Zhang
- Norton Neuroscience Institute, Norton Healthcare, Louisville, Kentucky, USA
| | - Nai-Kui Liu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Xinhua Hu
- Department of Biostatistics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Yuxiang Liu
- Mechanical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Xingjie Ping
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Qi Han
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Xiangbing Wu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Wenrui Qu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Sujuan Gao
- Department of Biostatistics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | | | - Xiaoming Jin
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Xiao-Ming Xu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA
| |
Collapse
|
2
|
Jakovcevski I, von Düring M, Lutz D, Vulović M, Hamad M, Reiss G, Förster E, Schachner M. Mice lacking perforin have improved regeneration of the injured femoral nerve. Neural Regen Res 2022; 17:1802-1808. [PMID: 35017441 PMCID: PMC8820721 DOI: 10.4103/1673-5374.332152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The role that the immune system plays after injury of the peripheral nervous system is still not completely understood. Perforin, a natural killer cell- and T-lymphocyte-derived enzyme that mediates cytotoxicity, plays important roles in autoimmune diseases, infections and central nervous system trauma, such as spinal cord injury. To dissect the roles of this single component of the immune response to injury, we tested regeneration after femoral nerve injury in perforin-deficient (Pfp–/–) and wild-type control mice. Single frame motion analysis showed better motor recovery in Pfp–/– mice compared with control mice at 4 and 8 weeks after injury. Retrograde tracing of the motoneuron axons regrown into the motor nerve branch demonstrated more correctly projecting motoneurons in the spinal cord of Pfp–/– mice compared with wild-types. Myelination of regrown axons measured by g-ratio was more extensive in Pfp–/– than in wild-type mice in the motor branch of the femoral nerve. Pfp–/– mice displayed more cholinergic synaptic terminals around cell bodies of spinal motoneurons after injury than the injured wild-types. We histologically analyzed lymphocyte infiltration 10 days after surgery and found that in Pfp–/– mice the number of lymphocytes in the regenerating nerves was lower than in wild-types, suggesting a closed blood-nerve barrier in Pfp–/– mice. We conclude that perforin restricts motor recovery after femoral nerve injury owing to decreased survival of motoneurons and reduced myelination.
Collapse
Affiliation(s)
- Igor Jakovcevski
- Institut für Anatomie und Klinische Morphologie, Universität Witten/Herdecke, Witten, Germany
| | - Monika von Düring
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany
| | - David Lutz
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany
| | - Maja Vulović
- Department of Anatomy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Mohammad Hamad
- Institut für Anatomie und Klinische Morphologie, Universität Witten/Herdecke, Witten, Germany
| | - Gebhard Reiss
- Institut für Anatomie und Klinische Morphologie, Universität Witten/Herdecke, Witten, Germany
| | - Eckart Förster
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany
| | - Melitta Schachner
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
| |
Collapse
|
3
|
Jakovcevski I, Schachner M. Perforin affects regeneration in a mouse spinal cord injury model. Int J Neurosci 2022; 132:1-12. [PMID: 32672480 DOI: 10.1080/00207454.2020.1796662] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/11/2020] [Accepted: 07/01/2020] [Indexed: 02/05/2023]
Abstract
MATERIALS AND METHODS Locomotor outcomes in perforin-deficient (Pfp-/-) mice and wild-type littermate controls were measured after severe compression injury of the lower thoracic spinal cord up to six weeks after injury. RESULTS According to both the Basso mouse scale score and single frame motion analysis, motor recovery of Pfp-/- mice was similar to wild-type controls. Interestingly, immunohistochemical analysis of cell types at six weeks after injury showed enhanced cholinergic reinnervation of spinal motor neurons caudal to the lesion site and neurofilament-positive structures at the injury site in Pfp-/- mice, whereas numbers of microglia/macrophages and astrocytes were decreased compared with controls. CONCLUSIONS We conclude that, although, loss of perforin does not change the locomotor outcome after injury, it beneficially affects diverse cellular features, such as number of axons, cholinergic synapses, astrocytes and microglia/macrophages at or caudal to the lesion site. Perforin's ability to contribute to Rag2's influence on locomotion was observed in mice doubly deficient in perforin and Rag2 which recovered better than Rag2-/- or Pfp-/- mice, suggesting that natural killer cells can cooperate with T- and B-cells in spinal cord injury.
Collapse
Affiliation(s)
- Igor Jakovcevski
- Center for Molecular Neurobiology Hamburg, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Melitta Schachner
- Center for Molecular Neurobiology Hamburg, University Hospital Hamburg-Eppendorf, Hamburg, Germany
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong, China
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
| |
Collapse
|
4
|
Aksic M, Poleksic J, Aleksic D, Petronijevic N, Radonjic NV, Jakovcevski M, Kapor S, Divac N, Filipovic BR, Jakovcevski I. Maternal Deprivation in Rats Decreases the Expression of Interneuron Markers in the Neocortex and Hippocampus. Front Neuroanat 2021; 15:670766. [PMID: 34168541 PMCID: PMC8217609 DOI: 10.3389/fnana.2021.670766] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/07/2021] [Indexed: 12/12/2022] Open
Abstract
Early life stress has profound effects on the development of the central nervous system. We exposed 9-day-old rat pups to a 24 h maternal deprivation (MD) and sacrificed them as young adults (60-day-old), with the aim to study the effects of early stress on forebrain circuitry. We estimated numbers of various immunohistochemically defined interneuron subpopulations in several neocortical regions and in the hippocampus. MD rats showed reduced numbers of parvalbumin-expressing interneurons in the CA1 region of the hippocampus and in the prefrontal cortex, compared with controls. Numbers of reelin-expressing and calretinin-expressing interneurons were also reduced in the CA1 and CA3 hippocampal areas, but unaltered in the neocortex of MD rats. The number of calbinin-expressing interneurons in the neocortex was similar in the MD rats compared with controls. We analyzed cell death in 15-day-old rats after MD and found no difference compared to control rats. Thus, our results more likely reflect the downregulation of markers than the actual loss of interneurons. To investigate synaptic activity in the hippocampus we immunostained for glutamatergic and inhibitory vesicular transporters. The number of inhibitory synapses was decreased in the CA1 and CA3 regions of the hippocampus in MD rats, with the normal number of excitatory synapses. Our results indicate complex, cell type-specific, and region-specific alterations in the inhibitory circuitry induced by maternal deprivation. Such alterations may underlie symptoms of MD at the behavioral level and possibly contribute to mechanisms by which early life stress causes neuropsychiatric disorders, such as schizophrenia.
Collapse
Affiliation(s)
- Milan Aksic
- Institute of Anatomy Niko Miljanić, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Joko Poleksic
- Institute of Anatomy Niko Miljanić, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Dubravka Aleksic
- Institute of Anatomy Niko Miljanić, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Natasa Petronijevic
- Institute of Medical and Clinical Biochemistry, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Nevena V Radonjic
- Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, United States
| | - Maja Jakovcevski
- Department of Anatomy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Slobodan Kapor
- Institute of Anatomy Niko Miljanić, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Nevena Divac
- Department of Pharmacology, Clinical Pharmacology and Toxicology, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Branislav R Filipovic
- Institute of Anatomy Niko Miljanić, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Igor Jakovcevski
- Abteilung für Neuroanatomie und Molekulare Hirnforschung, Ruhr-Universität Bochum, Bochum, Germany.,Institut für Anatomie und Klinische Morphologie, Universität Witten/Herdecke, Witten, Germany
| |
Collapse
|
5
|
Jakovčevski I, Förster E, Reiss G, Schachner M. Impact of Depletion of Microglia/Macrophages on Regeneration after Spinal Cord Injury. Neuroscience 2021; 459:129-141. [PMID: 33588005 DOI: 10.1016/j.neuroscience.2021.02.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 01/30/2023]
Abstract
Microglia/macrophages play important functional roles in regeneration after central nervous system injury. Infiltration of circulating macrophages and proliferation of resident microglia occur within minutes following spinal cord injury. Activated microglia/macrophages clear tissue debris, but activation over time may hamper repair. To study the role of these cells in regeneration after spinal cord injury we used CD11b-herpes simplex virus thymidine kinase (HSVTK) (TK) transgenic mice, in which viral thymidine kinase activates ganciclovir toxicity in CD11b-expressing myeloid cells, including macrophages and microglia. A severe reduction in number of these cells was seen in TK versus wild-type littermate mice at 1 week and 5 weeks after injury, and numbers of Mac-2 expressing activated microglia/macrophages were almost completely reduced at these time points. One week after injury TK mice showed better locomotor recovery, but recovery was similar to wild-type mice as measured weekly up to 5 weeks thereafter. At 5 weeks after injury, numbers of axons at the lesion site and neurons in the lumbar spinal cord did not differ between groups. Also, catecholaminergic innervation of spinal motoneurons was similar. However, cholinergic innervation was lower and glial scarring was increased in TK mice compared to wild-type mice. We conclude that reducing numbers of CD11b-expressing cells improves locomotor recovery in the early phase after spinal cord injury, but does not affect recovery in the following 4 weeks. These observations point to differences in outcomes of astrocytic response and cholinergic innervation under CD11b cell ablation, which are, however, not reflected in the locomotor parameters analyzed at 5 weeks after injury.
Collapse
Affiliation(s)
- Igor Jakovčevski
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany; Institut für Anatomie und Klinische Morphologie, Universität Witten/Herdecke, Witten, Germany; Center for Molecular Neurobiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
| | - Eckart Förster
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany
| | - Gebhard Reiss
- Institut für Anatomie und Klinische Morphologie, Universität Witten/Herdecke, Witten, Germany
| | - Melitta Schachner
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA.
| |
Collapse
|
6
|
Mille T, Quilgars C, Cazalets J, Bertrand SS. Acetylcholine and spinal locomotor networks: The insider. Physiol Rep 2021; 9:e14736. [PMID: 33527727 PMCID: PMC7851432 DOI: 10.14814/phy2.14736] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 01/07/2023] Open
Abstract
This article aims to review studies that have investigated the role of neurons that use the transmitter acetylcholine (ACh) in controlling the operation of locomotor neural networks within the spinal cord. This cholinergic system has the particularity of being completely intraspinal. We describe the different effects exerted by spinal cholinergic neurons on locomotor circuitry by the pharmacological activation or blockade of this propriospinal system, as well as describing its different cellular and subcellular targets. Through the activation of one ionotropic receptor, the nicotinic receptor, and five metabotropic receptors, the M1 to M5 muscarinic receptors, the cholinergic system exerts a powerful control both on synaptic transmission and locomotor network neuron excitability. Although tremendous advances have been made in our understanding of the spinal cholinergic system's involvement in the physiology and pathophysiology of locomotor networks, gaps still remain, including the precise role of the different subtypes of cholinergic neurons as well as their pre- and postsynaptic partners. Improving our knowledge of the propriospinal cholinergic system is of major relevance to finding new cellular targets and therapeutics in countering the debilitating effects of neurodegenerative diseases and restoring motor functions after spinal cord injury.
Collapse
Affiliation(s)
- Théo Mille
- Université de BordeauxCNRS UMR 5287INCIABordeauxFrance
| | | | | | | |
Collapse
|
7
|
Farizatto KLG, Almeida MF, Long RT, Bahr BA. Early Synaptic Alterations and Selective Adhesion Signaling in Hippocampal Dendritic Zones Following Organophosphate Exposure. Sci Rep 2019; 9:6532. [PMID: 31024077 PMCID: PMC6484076 DOI: 10.1038/s41598-019-42934-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/11/2019] [Indexed: 11/09/2022] Open
Abstract
Organophosphates account for many of the world's deadliest poisons. They inhibit acetylcholinesterase causing cholinergic crises that lead to seizures and death, while survivors commonly experience long-term neurological problems. Here, we treated brain explants with the organophosphate compound paraoxon and uncovered a unique mechanism of neurotoxicity. Paraoxon-exposed hippocampal slice cultures exhibited progressive declines in synaptophysin, synapsin II, and PSD-95, whereas reduction in GluR1 was slower and NeuN and Nissl staining showed no indications of neuronal damage. The distinctive synaptotoxicity was observed in dendritic zones of CA1 and dentate gyrus. Interestingly, declines in synapsin II dendritic labeling correlated with increased staining for β1 integrin, a component of adhesion receptors that regulate synapse maintenance and plasticity. The paraoxon-induced β1 integrin response was targeted to synapses, and the two-fold increase in β1 integrin was selective as other synaptic adhesion molecules were unchanged. Additionally, β1 integrin-cofilin signaling was triggered by the exposure and correlations were found between the extent of synaptic decline and the level of β1 integrin responses. These findings identified organophosphate-mediated early and lasting synaptotoxicity which can explain delayed neurological dysfunction later in life. They also suggest that the interplay between synaptotoxic events and compensatory adhesion responses influences neuronal fate in exposed individuals.
Collapse
Affiliation(s)
- Karen L G Farizatto
- Biotechnology Research and Training Center, University of North Carolina-Pembroke, Pembroke, North Carolina, USA
| | - Michael F Almeida
- Biotechnology Research and Training Center, University of North Carolina-Pembroke, Pembroke, North Carolina, USA
| | - Ronald T Long
- Biotechnology Research and Training Center, University of North Carolina-Pembroke, Pembroke, North Carolina, USA.,Department of Biology, University of North Carolina-Pembroke, Pembroke, North Carolina, USA
| | - Ben A Bahr
- Biotechnology Research and Training Center, University of North Carolina-Pembroke, Pembroke, North Carolina, USA. .,Department of Biology, University of North Carolina-Pembroke, Pembroke, North Carolina, USA. .,Department of Chemistry and Physics, University of North Carolina-Pembroke, Pembroke, North Carolina, USA.
| |
Collapse
|
8
|
Donato A, Kagias K, Zhang Y, Hilliard MA. Neuronal sub-compartmentalization: a strategy to optimize neuronal function. Biol Rev Camb Philos Soc 2019; 94:1023-1037. [PMID: 30609235 PMCID: PMC6617802 DOI: 10.1111/brv.12487] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 11/21/2018] [Accepted: 11/23/2018] [Indexed: 12/14/2022]
Abstract
Neurons are highly polarized cells that consist of three main structural and functional domains: a cell body or soma, an axon, and dendrites. These domains contain smaller compartments with essential roles for proper neuronal function, such as the axonal presynaptic boutons and the dendritic postsynaptic spines. The structure and function of these compartments have now been characterized in great detail. Intriguingly, however, in the last decade additional levels of compartmentalization within the axon and the dendrites have been identified, revealing that these structures are much more complex than previously thought. Herein we examine several types of structural and functional sub-compartmentalization found in neurons of both vertebrates and invertebrates. For example, in mammalian neurons the axonal initial segment functions as a sub-compartment to initiate the action potential, to select molecules passing into the axon, and to maintain neuronal polarization. Moreover, work in Drosophila melanogaster has shown that two distinct axonal guidance receptors are precisely clustered in adjacent segments of the commissural axons both in vivo and in vitro, suggesting a cell-intrinsic mechanism underlying the compartmentalized receptor localization. In Caenorhabditis elegans, a subset of interneurons exhibits calcium dynamics that are localized to specific sections of the axon and control the gait of navigation, demonstrating a regulatory role of compartmentalized neuronal activity in behaviour. These findings have led to a number of new questions, which are important for our understanding of neuronal development and function. How are these sub-compartments established and maintained? What molecular machinery and cellular events are involved? What is their functional significance for the neuron? Here, we reflect on these and other key questions that remain to be addressed in this expanding field of biology.
Collapse
Affiliation(s)
- Alessandra Donato
- Clem Jones Centre for Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Konstantinos Kagias
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA 02138, U.S.A
| | - Yun Zhang
- Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA 02138, U.S.A
| | - Massimo A Hilliard
- Clem Jones Centre for Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| |
Collapse
|
9
|
Kleene R, Loers G, Jakovcevski I, Mishra B, Schachner M. Histone H1 improves regeneration after mouse spinal cord injury and changes shape and gene expression of cultured astrocytes. Restor Neurol Neurosci 2019; 37:291-313. [PMID: 31227672 DOI: 10.3233/rnn-190903] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND We have shown that histone H1 is a binding partner for polysialic acid (PSA) and that it improves functional recovery, axon regrowth/sprouting, and target reinnervation after mouse femoral nerve injury. OBJECTIVE Here, we analyzed whether histone H1 affects functional recovery, axon regrowth/sprouting, and target reinnervation after spinal cord injury of adult mice. Furthermore, we tested in vitro histone H1's effect on astrocytic gene expression, cell shape and migration as well as on cell survival of cultured motoneurons. METHODS We applied histone H1 to compressed spinal cord and determined functional recovery and number of fibrillary acidic protein (GFAP)- and neuron-glial antigen 2 (NG2)- positive glial cells, which contribute to glial scarring. Histone H1's effect on migration of astrocytes, astrocytic gene expression and motoneuronal survival was determined using scratch-wounded astroglial monolayer cultures, astrocyte cultures for microarray analysis, and motoneuron cell culture under oxidative stress conditions, respectively. RESULTS Histone H1 application improves locomotor functions and enhances monoaminergic and cholinergic reinnervation of the spinal cord. Expression levels of GFAP and NG2 around the lesion site were decreased in histone H1-treated mice relative to vehicle-treated mice six weeks after injury. Histone H1 reduced astrocytic migration, changed the shape of GFAP- and NG2-positive glial cells and altered gene expression. Gene ontology enrichment analysis indicated that in particular genes coding for proteins involved in proliferation, differentiation, migration and apoptosis are dysregulated. The up- and down-regulation of distinct genes was confirmed by qPCR and Western blot analysis. Moreover, histone H1 reduced hydrogen peroxide-induced cell death of cultured motoneurons. CONCLUSIONS The combined observations indicate that histone H1 locally applied to the lesion site, improves regeneration after spinal cord injury. Some of these beneficial functions of histone H1 in vivo and in vitro can be attributed to its interaction with PSA-carrying neural cell adhesion molecule.
Collapse
Affiliation(s)
- Ralf Kleene
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Gabriele Loers
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Igor Jakovcevski
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Bibhudatta Mishra
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Melitta Schachner
- Department of Cell Biology and Neuroscience, Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, NJ, USA
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong, China
| |
Collapse
|