scholarly journals Regeneration of Functional Neurons After Spinal Cord Injury via in situ NeuroD1-Mediated Astrocyte-to-Neuron Conversion

2020 ◽  
Vol 8 ◽  
Author(s):  
Brendan Puls ◽  
Yan Ding ◽  
Fengyu Zhang ◽  
Mengjie Pan ◽  
Zhuofan Lei ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Dorsal Horn ◽  
Cell Fate ◽  
High Efficiency ◽  
Neuronal Loss ◽  
Reactive Astrocytes ◽  
Spinal Cord Neurons ◽  
Cord Injury

Spinal cord injury (SCI) often leads to impaired motor and sensory functions, partially because the injury-induced neuronal loss cannot be easily replenished through endogenous mechanisms. In vivo neuronal reprogramming has emerged as a novel technology to regenerate neurons from endogenous glial cells by forced expression of neurogenic transcription factors. We have previously demonstrated successful astrocyte-to-neuron conversion in mouse brains with injury or Alzheimer's disease by overexpressing a single neural transcription factor NeuroD1. Here we demonstrate regeneration of spinal cord neurons from reactive astrocytes after SCI through AAV NeuroD1-based gene therapy. We find that NeuroD1 converts reactive astrocytes into neurons in the dorsal horn of stab-injured spinal cord with high efficiency (~95%). Interestingly, NeuroD1-converted neurons in the dorsal horn mostly acquire glutamatergic neuronal subtype, expressing spinal cord-specific markers such as Tlx3 but not brain-specific markers such as Tbr1, suggesting that the astrocytic lineage and local microenvironment affect the cell fate after conversion. Electrophysiological recordings show that the NeuroD1-converted neurons can functionally mature and integrate into local spinal cord circuitry by displaying repetitive action potentials and spontaneous synaptic responses. We further show that NeuroD1-mediated neuronal conversion can occur in the contusive SCI model with a long delay after injury, allowing future studies to further evaluate this in vivo reprogramming technology for functional recovery after SCI. In conclusion, this study may suggest a paradigm shift from classical axonal regeneration to neuronal regeneration for spinal cord repair, using in vivo astrocyte-to-neuron conversion technology to regenerate functional new neurons in the gray matter.

scholarly journals Regeneration of dorsal spinal cord neurons after injury via in situ NeuroD1-mediated astrocyte-to-neuron conversion

2019 ◽  
Author(s):  
Brendan Puls ◽  
Yan Ding ◽  
Fengyu Zhang ◽  
Mengjie Pan ◽  
Zhuofan Lei ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Cell Fate ◽  
High Efficiency ◽  
Reactive Astrocytes ◽  
Dorsal Spinal Cord ◽  
Spinal Cord Neurons ◽  
Cord Injury ◽  
Dorsal Spinal

AbstractSpinal cord injury (SCI) often leads to impaired motor and sensory functions, partially because the injury-induced neuronal loss cannot be easily replenished through endogenous mechanisms. In vivo neuronal reprogramming has emerged as a novel technology to regenerate neurons from endogenous glial cells by forced expression of neurogenic transcription factors. We have previously demonstrated successful astrocyte-to-neuron conversion in mouse brains with injury or Alzheimer’s disease by overexpressing a single neural transcription factor NeuroD1 via retroviruses. Here we demonstrate regeneration of dorsal spinal cord neurons from reactive astrocytes after SCI via adeno-associated virus (AAV), a more clinically relevant gene delivery system. We find that NeuroD1 converts reactive astrocytes into neurons in the dorsal horn of stab-injured spinal cord with high efficiency (∼95%). Interestingly, NeuroD1-converted neurons in the dorsal horn mostly acquire glutamatergic neuronal subtype, expressing spinal cord-specific markers such as Tlx3 but not brain-specific markers such as Tbr1, suggesting that the astrocytic lineage and local microenvironment affect the cell fate of conversion. Electrophysiological recordings show that the NeuroD1-converted neurons can functionally mature and integrate into local spinal cord circuitry by displaying repetitive action potentials and spontaneous synaptic responses. We further show that NeuroD1-mediated neuronal conversion can occur in the contusive SCI model, allowing future studies of evaluating this reprogramming technology for functional recovery after SCI. In conclusion, this study may suggest a paradigm shift for spinal cord repair using in vivo astrocyte-to-neuron conversion technology to generate functional neurons in the grey matter.

scholarly journals Characterizing the Neuroprotective Effects of S/B Remedy (Scutellaria baicalensis Georgi and Bupleurum scorzonerifolfium Willd) in Spinal Cord Injury

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1885 ◽  
Author(s):  
Tsung-Hsi Tu ◽  
Dann-Ying Liou ◽  
Di-You Lin ◽  
Hsin-Chun Yang ◽  
Ching-Jung Chen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Acute Stage ◽  
Scutellaria Baicalensis ◽  
Therapeutic Interventions ◽  
Neuroprotective Effects ◽  
Spinal Cord Neurons ◽  
Scutellaria Baicalensis Georgi ◽  
Cord Injury

The main causes of dysfunction after a spinal cord injury (SCI) include primary and secondary injuries that occur during the first minutes, hours, to days after injury. This treatable secondary cascade provides a window of opportunity for delivering therapeutic interventions. An S/B remedy (Scutellaria baicalensis Georgi and Bupleurum scorzonerifolfium Willd) has anti-inflammatory, cytoprotective, and anticarcinogenic effects in liver or neurodegenerative diseases. The present work examined the effect of S/B on injured spinal cord neurons in cultures and in vivo. S/B effectively reduced peroxide toxicity and lipopolysaccharide stimulation in both spinal cord neuron/glial and microglial cultures with the involvement of PKC and HSP70. The effect of S/B was further conducted in contusive SCI rats. Intraperitoneal injections of S/B to SCI rats preserved spinal cord tissues and effectively attenuated microglial activation. Consistently, S/B treatment significantly improved hindlimb functions of SCI rats. In the acute stage of injury, S/B treatment markedly reduced the levels of ED1 expression and lactate and had a tendency to decrease lipid peroxidation. Taken together, we demonstrated long-term hindlimb restoration alongside histological improvements with systemic S/B remedy treatment in a clinically relevant model of contusive SCI. Our findings highlight the potential of an S/B remedy for acute therapeutic intervention after SCI.

scholarly journals mir-21a-5p promote the progress of inflammation after Traumatic Spinal Cord Injury via up-regulating neurotoxic reactive astrocyte (A1) polarization by inhibiting CNTF/STAT3/Nkrf pathway

2020 ◽  
Author(s):  
Yining Zhang ◽  
Tingting Meng ◽  
Jianan Chen ◽  
Ying Zhang ◽  
Jianning Kang ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Reactive Astrocytes ◽  
Luciferase Reporter ◽  
Chip Assay ◽  
Qrt Pcr ◽  
Pulldown Assay ◽  
Cord Injury

Abstract Background Reactive astrocytes play an important role in Traumatic Spinal Cord Injury (TSCI). Interestingly, naive astrocytes can easily transform into neurotoxic reactive astrocytes(A1s) when inflammatory stimulation occurs. Previous researches have reported that miR-21a-5p is involved in the regulation of various stages of Spinal Cord Injury (SCI). However, it is not clear whether miR-21a-5p affected the polarization of reactive astrocytes. The purpose of our study was to detect the effects and mechanism of miR-21a-5p in the induction of neurotoxic reactive astrocytes (A1s) formation. Methods Gene chip assay and qRT-PCR were used to detect the expression of Cntfr α in TSCI models or sham operation. Bioinformatics analysis was used to speculate the potential targeting of miR-21a-5p, which was further confirmed by qRT-PCR, western blotting, a dual-luciferase reporter assay, and RNA pulldown assay. In vivo, the TSCI model was performed by a 68099Ⅱ precision percussion device, and the A1s phenotype was identified by immunofluorescence staining. In vitro, A1s were induced by IL-1 α, TNF-α, and C1q. A1s and neuroprotective reactive astrocytes (A2s) markers were confirmed by qRT-PCR, western blotting, and immunofluorescence. ChIP assay was used to explore the targeting gene of STAT3, the downstream of Cntfr α. Results The expression of miR-21a-5p was significantly increased while Cntfr α was decreased since naive astrocytes transformed into A1s after 3 days post-TSCI. In addition, the mRNA and protein of Cntfr α were decreased while miR-21a-5p was overexpressed. The binding site between miR-21a-5p and Cntfr α was further confirmed by the dual-luciferase reporter and RNA pulldown assay. We also discovered that A1s markers were decreased while markers of A2s were increased with the pretreatment of CNTF. Chromatin immunoprecipitation (ChIP) assay was used to prove that CNTF inhibited A1s induction by activating the expression of Nkrf via the CNTF/STAT3 pathway. Downregulation of miR-21a-5p enhanced the inhibitory effect of CNTF in A1s in vitro. In vivo, the expression of A1s markers significantly decreased with the treatment of antagomir-21, while Cntfr α siRNA treatment was just the opposite. Conclusion We observed that increased miR-21a-5p down-regulated Cntfr α in A1s induced by TSCI, promoting the inflammatory process. In addition, we also identified the effect and potential mechanism of CNTF, a specific ligand of CNTFR α, on inhibiting naive astrocytes transformed into A1s for the first time. Collectively, our studies demonstrated that targeting miR-21a-5p is a prospective therapy for curing TSCI.

scholarly journals A Collagen-Based Scaffold for Promoting Neural Plasticity in a Rat Model of Spinal Cord Injury

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2245
Author(s):  
Jue-Zong Yeh ◽  
Ding-Han Wang ◽  
Juin-Hong Cherng ◽  
Yi-Wen Wang ◽  
Gang-Yi Fan ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Rat Model ◽  
Neural Plasticity ◽  
Collagen Scaffold ◽  
Glial Scar ◽  
Beneficial Effects ◽  
Cord Injury

In spinal cord injury (SCI) therapy, glial scarring formed by activated astrocytes is a primary problem that needs to be solved to enhance axonal regeneration. In this study, we developed and used a collagen scaffold for glial scar replacement to create an appropriate environment in an SCI rat model and determined whether neural plasticity can be manipulated using this approach. We used four experimental groups, as follows: SCI-collagen scaffold, SCI control, normal spinal cord-collagen scaffold, and normal control. The collagen scaffold showed excellent in vitro and in vivo biocompatibility. Immunofluorescence staining revealed increased expression of neurofilament and fibronectin and reduced expression of glial fibrillary acidic protein and anti-chondroitin sulfate in the collagen scaffold-treated SCI rats at 1 and 4 weeks post-implantation compared with that in untreated SCI control. This indicates that the collagen scaffold implantation promoted neuronal survival and axonal growth within the injured site and prevented glial scar formation by controlling astrocyte production for their normal functioning. Our study highlights the feasibility of using the collagen scaffold in SCI repair. The collagen scaffold was found to exert beneficial effects on neuronal activity and may help in manipulating synaptic plasticity, implying its great potential for clinical application in SCI.

scholarly journals Reactive astrocytes undergo M1 microglia/macrohpages-induced necroptosis in spinal cord injury

2016 ◽  
Vol 11 (1) ◽  
Author(s):  
Hong Fan ◽  
Kun Zhang ◽  
Lequn Shan ◽  
Fang Kuang ◽  
Kun Chen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Reactive Astrocytes ◽  
Cord Injury

scholarly journals Immunosuppressants Affect Human Neural Stem Cells In Vitro but Not in an In Vivo Model of Spinal Cord Injury

2013 ◽  
Vol 2 (10) ◽  
pp. 731-744 ◽  
Author(s):  
Christopher J. Sontag ◽  
Hal X. Nguyen ◽  
Noriko Kamei ◽  
Nobuko Uchida ◽  
Aileen J. Anderson ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Stem Cells ◽  
Spinal Cord Injury ◽  
Neural Stem Cells ◽  
In Vivo Model ◽  
Human Neural Stem Cells ◽  
Cord Injury

scholarly journals Depolarization and electrical stimulation enhance in vitro and in vivo sensory axon growth after spinal cord injury

2018 ◽  
Vol 300 ◽  
pp. 247-258 ◽  
Author(s):  
Ioana Goganau ◽  
Beatrice Sandner ◽  
Norbert Weidner ◽  
Karim Fouad ◽  
Armin Blesch
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Electrical Stimulation ◽  
Axon Growth ◽  
Sensory Axon ◽  
Cord Injury

An in vivo model of anti-inflammatory activity of subdural dexamethasone following the spinal cord injury

2016 ◽  
Vol 50 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Jacek M. Kwiecien ◽  
Bozena Jarosz ◽  
Wendy Oakden ◽  
Michal Klapec ◽  
Greg J. Stanisz ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Inflammatory Activity ◽  
In Vivo Model ◽  
Cord Injury ◽  
Anti Inflammatory

Transplantation of Neural Stem/Progenitor Cells at Different Locations in Mice with Spinal Cord Injury

2014 ◽  
Vol 23 (11) ◽  
pp. 1451-1464 ◽  
Author(s):  
Hiroki Iwai ◽  
Satoshi Nori ◽  
Soraya Nishimura ◽  
Akimasa Yasuda ◽  
Morito Takano ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Progenitor Cells ◽  
Functional Recovery ◽  
Control Group ◽  
Cord Injury ◽  
Neural Stem Progenitor Cells ◽  
Neurotropic Factor ◽  
Transplantation Site

Transplantation of neural stem/progenitor cells (NS/PCs) promotes functional recovery after spinal cord injury (SCI); however, few studies have examined the optimal site of NS/PC transplantation in the spinal cord. The purpose of this study was to determine the optimal transplantation site of NS/PCs for the treatment of SCI. Wild-type mice were generated with contusive SCI at the T10 level, and NS/PCs were derived from fetal transgenic mice. These NS/PCs ubiquitously expressed ffLuc-cp156 protein (Venus and luciferase fusion protein) and so could be detected by in vivo bioluminescence imaging 9 days postinjury. NS/PCs (low: 250,000 cells per mouse; high: 1 million cells per mouse) were grafted into the spinal cord at the lesion epicenter (E) or at rostral and caudal (RC) sites. Phosphate-buffered saline was injected into E as a control. Motor functional recovery was better in each of the transplantation groups (E-Low, E-High, RC-Low, and RC-High) than in the control group. The photon counts of the grafted NS/PCs were similar in each of the four transplantation groups, suggesting that the survival of NS/PCs was fairly uniform when more than a certain threshold number of cells were transplanted. Quantitative RT-PCR analyses demonstrated that brain-derived neurotropic factor expression was higher in the RC segment than in the E segment, and this may underlie why NS/PCs more readily differentiated into neurons than into astrocytes in the RC group. The location of the transplantation site did not affect the area of spared fibers, angiogenesis, or the expression of any other mediators. These findings indicated that the microenvironments of the E and RC sites are able to support NS/PCs transplanted during the subacute phase of SCI similarly. Optimally, a certain threshold number of NS/PCs should be grafted into the E segment to avoid damaging sites adjacent to the lesion during the injection procedure.

Sign in / Sign up

Export Citation Format

Share Document