scholarly journals Cellular response to spinal cord injury in regenerative and non-regenerative stages in Xenopus laevis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Gabriela Edwards-Faret ◽  
Karina González-Pinto ◽  
Arantxa Cebrián-Silla ◽  
Johany Peñailillo ◽  
José Manuel García-Verdugo ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Extracellular Matrix ◽  
Xenopus Laevis ◽  
Cellular Response ◽  
Central Canal ◽  
Spinal Cord Regeneration ◽  
Post Injury ◽  
Cord Injury ◽  
Regenerative Stage

Abstract Background The efficient regenerative abilities at larvae stages followed by a non-regenerative response after metamorphosis in froglets makes Xenopus an ideal model organism to understand the cellular responses leading to spinal cord regeneration. Methods We compared the cellular response to spinal cord injury between the regenerative and non-regenerative stages of Xenopus laevis. For this analysis, we used electron microscopy, immunofluorescence and histological staining of the extracellular matrix. We generated two transgenic lines: i) the reporter line with the zebrafish GFAP regulatory regions driving the expression of EGFP, and ii) a cell specific inducible ablation line with the same GFAP regulatory regions. In addition, we used FACS to isolate EGFP+ cells for RNAseq analysis. Results In regenerative stage animals, spinal cord regeneration triggers a rapid sealing of the injured stumps, followed by proliferation of cells lining the central canal, and formation of rosette-like structures in the ablation gap. In addition, the central canal is filled by cells with similar morphology to the cells lining the central canal, neurons, axons, and even synaptic structures. Regeneration is almost completed after 20 days post injury. In non-regenerative stage animals, mostly damaged tissue was observed, without clear closure of the stumps. The ablation gap was filled with fibroblast-like cells, and deposition of extracellular matrix components. No reconstruction of the spinal cord was observed even after 40 days post injury. Cellular markers analysis confirmed these histological differences, a transient increase of vimentin, fibronectin and collagen was detected in regenerative stages, contrary to a sustained accumulation of most of these markers, including chondroitin sulfate proteoglycans in the NR-stage. The zebrafish GFAP transgenic line was validated, and we have demonstrated that is a very reliable and new tool to study the role of neural stem progenitor cells (NSPCs). RNASeq of GFAP::EGFP cells has allowed us to clearly demonstrate that indeed these cells are NSPCs. On the contrary, the GFAP::EGFP transgene is mainly expressed in astrocytes in non-regenerative stages. During regenerative stages, spinal cord injury activates proliferation of NSPCs, and we found that are mainly differentiated into neurons and glial cells. Specific ablation of these cells abolished proper regeneration, confirming that NSPCs cells are necessary for functional regeneration of the spinal cord. Conclusions The cellular response to spinal cord injury in regenerative and non-regenerative stages is profoundly different between both stages. A key hallmark of the regenerative response is the activation of NSPCs, which massively proliferate, and are differentiated into neurons to reconstruct the spinal cord. Also very notably, no glial scar formation is observed in regenerative stages, but a transient, glial scar-like structure is formed in non-regenerative stage animals.

scholarly journals Cellular Response to Spinal Cord Injury in Regenerative and Non-Regenerative Stages in Xenopus Laevis

2020 ◽  
Author(s):  
Gabriela Edwards-Faret ◽  
Karina González-Pinto ◽  
Arantxa Cebrián-Silla ◽  
Johany Peñailillo ◽  
José Manuel García-Verdugo ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Extracellular Matrix ◽  
Xenopus Laevis ◽  
Cellular Response ◽  
Central Canal ◽  
Spinal Cord Regeneration ◽  
Post Injury ◽  
Cord Injury ◽  
Regenerative Stage

Abstract Background The efficient regenerative abilities at larvae stages followed by a non-regenerative response after metamorphosis in froglets makes Xenopus an ideal model organism to understand the cellular responses leading to spinal cord regeneration.Methods We compared the cellular response to spinal cord injury between the regenerative and non-regenerative stages of Xenopus laevis. For this analysis, we used electron microscopy, immunofluorescence and histological staining of the extracellular matrix. We generated two transgenic lines: i) the reporter line with the zebrafish GFAP regulatory regions driving the expression of EGFP, and ii) a cell specific inducible ablation line with the same GFAP regulatory regions. In addition, we used FACS to isolate EGFP+ cells for RNAseq analysis.Results In regenerative stage animals, spinal cord regeneration triggers a rapid sealing of the injured stumps, followed by proliferation of cells lining the central canal, and formation of rosette-like structures in the ablation gap. In addition, the central canal is filled by cells with similar morphology to the cells lining the central canal, neurons, axons, and even synaptic structures. Regeneration is almost completed after 20 days post injury. In non-regenerative stage animals, mostly damaged tissue was observed, without clear closure of the stumps. The ablation gap was filled with fibroblast-like cells, and deposition of extracellular matrix components. No reconstruction of the spinal cord was observed even after 40 days post injury. Cellular markers analysis confirmed these histological differences, a transient increase of vimentin, fibronectin and collagen was detected in regenerative stages, contrary to a sustained accumulation of most of these markers, including chondroitin sulfate proteoglycans in the NR-stage. The zebrafish GFAP transgenic line was validated, and we have demonstrated that is a very reliable and new tool to study the role of neural stem progenitor cells (NSPC). RNASeq of GFAP-EGFP cells allowed a clear demonstration that indeed these cells are NSPC. On the contrary, the GFAP-EGFP transgene is mainly expressed in astrocytes in non-regenerative stages. During regenerative stages, spinal cord injury activates proliferation of NSPC, and we found that are mainly fated to form neurons and glial cells. Specific ablation of these cells abolished proper regeneration, confirming that NSPC cells are necessary for functional regeneration of the spinal cord. Conclusions The cellular response to spinal cord injury in regenerative and non-regenerative stages is profoundly different between both stages. A key hallmark of the regenerative response is the activation of NSPC, which massively proliferate to reconstitute the spinal cord, and are differentiated into neurons. Also very notably, no glial scar formation is observed in regenerative stages, but a transient, glial scar-like structure is formed in non-regenerative stage animals.

scholarly journals CRISPR gRNA phenotypic screening in zebrafish reveals pro-regenerative genes in spinal cord injury

PLoS Genetics ◽  
2021 ◽  
Vol 17 (4) ◽  
pp. e1009515
Author(s):  
Marcus Keatinge ◽  
Themistoklis M. Tsarouchas ◽  
Tahimina Munir ◽  
Nicola J. Porter ◽  
Juan Larraz ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Spinal Injury ◽  
Spinal Cord Regeneration ◽  
Post Injury ◽  
Highly Active ◽  
Cord Injury ◽  
Mechanistic Basis ◽  
Acute Injection

Zebrafish exhibit robust regeneration following spinal cord injury, promoted by macrophages that control post-injury inflammation. However, the mechanistic basis of how macrophages regulate regeneration is poorly understood. To address this gap in understanding, we conducted a rapid in vivo phenotypic screen for macrophage-related genes that promote regeneration after spinal injury. We used acute injection of synthetic RNA Oligo CRISPR guide RNAs (sCrRNAs) that were pre-screened for high activity in vivo. Pre-screening of over 350 sCrRNAs allowed us to rapidly identify highly active sCrRNAs (up to half, abbreviated as haCRs) and to effectively target 30 potentially macrophage-related genes. Disruption of 10 of these genes impaired axonal regeneration following spinal cord injury. We selected 5 genes for further analysis and generated stable mutants using haCRs. Four of these mutants (tgfb1a, tgfb3, tnfa, sparc) retained the acute haCR phenotype, validating the approach. Mechanistically, tgfb1a haCR-injected and stable mutant zebrafish fail to resolve post-injury inflammation, indicated by prolonged presence of neutrophils and increased levels of il1b expression. Inhibition of Il-1β rescues the impaired axon regeneration in the tgfb1a mutant. Hence, our rapid and scalable screening approach has identified functional regulators of spinal cord regeneration, but can be applied to any biological function of interest.

scholarly journals Time-Course Changes of Extracellular Matrix Encoding Genes Expression Level in the Spinal Cord Following Contusion Injury—A Data-Driven Approach

2021 ◽  
Vol 22 (4) ◽  
pp. 1744
Author(s):  
Andrea Bighinati ◽  
Zahra Khalajzeyqami ◽  
Vito Antonio Baldassarro ◽  
Luca Lorenzini ◽  
Maura Cescatti ◽  
...  
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Extracellular Matrix ◽  
Time Course ◽  
Post Injury ◽  
Active Lesion ◽  
Ecm Remodeling ◽  
Cord Injury ◽  
Data Driven Approach

The involvement of the extracellular matrix (ECM) in lesion evolution and functional outcome is well recognized in spinal cord injury. Most attention has been dedicated to the “core” area of the lesion and scar formation, while only scattered reports consider ECM modification based on the temporal evolution and the segments adjacent to the lesion. In this study, we investigated the expression profile of 100 genes encoding for ECM proteins at 1, 8 and 45 days post-injury, in the spinal cord segments rostral and caudal to the lesion and in the scar segment, in a rat model. During both the active lesion phases and the lesion stabilization, we observed an asymmetric gene expression induced by the injury, with a higher regulation in the rostral segment of genes involved in ECM remodeling, adhesion and cell migration. Using bioinformatic approaches, the metalloproteases inhibitor Timp1 and the hyaluronan receptor Cd44 emerged as the hub genes at all post-lesion times. Results from the bioinformatic gene expression analysis were then confirmed at protein level by tissue analysis and by cell culture using primary astrocytes. These results indicated that ECM regulation also takes place outside of the lesion area in spinal cord injury.

scholarly journals D-dopachrome tautomerase activates COX2/PGE2 pathway of astrocytes to mediate inflammation following spinal cord injury

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Huiyuan Ji ◽  
Yuxin Zhang ◽  
Chen Chen ◽  
Hui Li ◽  
Bingqiang He ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Signal Pathways ◽  
Post Injury ◽  
Dopachrome Tautomerase ◽  
Protein Levels ◽  
Cytokines And Chemokines ◽  
Cord Injury ◽  
Mitogen Activated Protein ◽  
Spinal Cord Contusion

Abstract Background Astrocytes are the predominant glial cell type in the central nervous system (CNS) that can secrete various cytokines and chemokines mediating neuropathology in response to danger signals. D-dopachrome tautomerase (D-DT), a newly described cytokine and a close homolog of macrophage migration inhibitory factor (MIF) protein, has been revealed to share an overlapping function with MIF in some ways. However, its cellular distribution pattern and mediated astrocyte neuropathological function in the CNS remain unclear. Methods A contusion model of the rat spinal cord was established. The protein levels of D-DT and PGE2 synthesis-related proteinase were assayed by Western blot and immunohistochemistry. Primary astrocytes were stimulated by different concentrations of D-DT in the presence or absence of various inhibitors to examine relevant signal pathways. The post-injury locomotor functions were assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale. Results D-DT was inducibly expressed within astrocytes and neurons, rather than in microglia following spinal cord contusion. D-DT was able to activate the COX2/PGE2 signal pathway of astrocytes through CD74 receptor, and the intracellular activation of mitogen-activated protein kinases (MAPKs) was involved in the regulation of D-DT action. The selective inhibitor of D-DT was efficient in attenuating D-DT-induced astrocyte production of PGE2 following spinal cord injury, which contributed to the improvement of locomotor functions. Conclusion Collectively, these data reveal a novel inflammatory activator of astrocytes following spinal cord injury, which might be beneficial for the development of anti-inflammation drug in neuropathological CNS.

scholarly journals Spinal Cord Injury Increases Pro-inflammatory Cytokine Expression in Kidney at Acute and Sub-chronic Stages

Inflammation ◽  
2021 ◽  
Author(s):  
Shangrila Parvin ◽  
Clintoria R. Williams ◽  
Simone A. Jarrett ◽  
Sandra M. Garraway
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Inflammatory Response ◽  
Inflammatory Cytokine ◽  
Cardiovascular Health ◽  
Mrna Levels ◽  
Post Injury ◽  
Cord Injury ◽  
And Function ◽  
The Impact

Abstract— Accumulating evidence supports that spinal cord injury (SCI) produces robust inflammatory plasticity. We previously showed that the pro-inflammatory cytokine tumor necrosis factor (TNF)α is increased in the spinal cord after SCI. SCI also induces a systemic inflammatory response that can impact peripheral organ functions. The kidney plays an important role in maintaining cardiovascular health. However, SCI-induced inflammatory response in the kidney and the subsequent effect on renal function have not been well characterized. This study investigated the impact of high and low thoracic (T) SCI on C-fos, TNFα, interleukin (IL)-1β, and IL-6 expression in the kidney at acute and sub-chronic timepoints. Adult C57BL/6 mice received a moderate contusion SCI or sham procedures at T4 or T10. Uninjured mice served as naïve controls. mRNA levels of the proinflammatory cytokines IL-1β, IL-6, TNFα, and C-fos, and TNFα and C-fos protein expression were assessed in the kidney and spinal cord 1 day and 14 days post-injury. The mRNA levels of all targets were robustly increased in the kidney and spinal cord, 1 day after both injuries. Whereas IL-6 and TNFα remained elevated in the spinal cord at 14 days after SCI, C-fos, IL-6, and TNFα levels were sustained in the kidney only after T10 SCI. TNFα protein was significantly upregulated in the kidney 1 day after both T4 and T10 SCI. Overall, these results clearly demonstrate that SCI induces robust systemic inflammation that extends to the kidney. Hence, the presence of renal inflammation can substantially impact renal pathophysiology and function after SCI.

scholarly journals Extracellular matrix-regulated neural differentiation of human multipotent marrow progenitor cells enhances functional recovery after spinal cord injury

2014 ◽  
Vol 14 (10) ◽  
pp. 2488-2499 ◽  
Author(s):  
Win-Ping Deng ◽  
Chi-Chiang Yang ◽  
Liang-Yo Yang ◽  
Chun-Wei D. Chen ◽  
Wei-Hong Chen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Extracellular Matrix ◽  
Progenitor Cells ◽  
Functional Recovery ◽  
Neural Differentiation ◽  
Cord Injury

Spinal Cord Tissue Bridges Validation Study: Predictive Relationships With Sensory Scores Following Cervical Spinal Cord Injury

2021 ◽  
Author(s):  
Andrew C. Smith ◽  
Denise R. O’Dell ◽  
Wesley A. Thornton ◽  
David Dungan ◽  
Eli Robinson ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
External Validation ◽  
Inpatient Rehabilitation ◽  
Spinal Cord Tissue ◽  
Light Touch ◽  
Post Injury ◽  
Data Set ◽  
Cord Injury ◽  
Predictive Relationships

Background: Using magnetic resonance imaging (MRI), widths of ventral tissue bridges demonstrated significant predictive relationships with future pinprick sensory scores, and widths of dorsal tissue bridges demonstrated significant predictive relationships with future light touch sensory scores, following spinal cord injury (SCI). These studies involved smaller participant numbers, and external validation of their findings is warranted. Objectives: The purpose of this study was to validate these previous findings using a larger independent data set. Methods: Widths of ventral and dorsal tissue bridges were quantified using MRI in persons post cervical level SCI (average 3.7 weeks post injury), and pinprick and light touch sensory scores were acquired at discharge from inpatient rehabilitation (average 14.3 weeks post injury). Pearson product-moments were calculated and linear regression models were created from these data. Results: Wider ventral tissue bridges were significantly correlated with pinprick scores (r = 0.31, p < 0.001, N = 136) and wider dorsal tissue bridges were significantly correlated with light touch scores (r = 0.31, p < 0.001, N = 136) at discharge from inpatient rehabilitation. Conclusion: This retrospective study’s results provide external validation of previous findings, using a larger sample size. Following SCI, ventral tissue bridges hold significant predictive relationships with future pinprick sensory scores and dorsal tissue bridges hold significant predictive relationships with future light touch sensory scores.

scholarly journals Reaction of ependymal cells to spinal cord injury: a potential role for oncostatin pathway and microglial cells

2021 ◽  
Author(s):  
R. Chevreau ◽  
H Ghazale ◽  
C Ripoll ◽  
C Chalfouh ◽  
Q Delarue ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Glial Cells ◽  
Mapk Signaling ◽  
Central Canal ◽  
Microglial Cells ◽  
Ependymal Cells ◽  
Rna Profiling ◽  
Cord Injury

AbstractEpendymal cells with stem cell properties reside in the adult spinal cord around the central canal. They rapidly activate and proliferate after spinal cord injury, constituting a source of new cells. They produce neurons and glial cells in lower vertebrates but they mainly generate glial cells in mammals. The mechanisms underlying their activation and their glial-biased differentiation in mammals remain ill-defined. This represents an obstacle to control these cells. We addressed this issue using RNA profiling of ependymal cells before and after injury. We found that these cells activate STAT3 and ERK/MAPK signaling during injury and downregulate cilia-associated genes and FOXJ1, a central transcription factor in ciliogenesis. Conversely, they upregulate 510 genes, six of them more than 20 fold, namely Crym, Ecm1, Ifi202b, Nupr1, Rbp1, Thbs2 and Osmr. OSMR is the receptor for the inflammatory cytokine oncostatin (OSM) and we studied its regulation and role using neurospheres derived from ependymal cells. We found that OSM induces strong OSMR and p-STAT3 expression together with proliferation reduction and astrocytic differentiation. Conversely, production of oligodendrocyte-lineage OLIG1+ cells was reduced. OSM is specifically expressed by microglial cells and was strongly upregulated after injury. We observed microglial cells apposed to ependymal cells in vivo and co-cultures experiments showed that these cells upregulate OSMR in neurosphere cells. Collectively, these results support the notion that microglial cells and OSMR/OSM pathway regulate ependymal cells in injury. In addition, the generated high throughput data provides a unique molecular resource to study how ependymal cell react to spinal cord lesion.

The Role of Neuroinflammation in the Response to Spinal Cord Injury

2021 ◽  
Author(s):  
Olivia H. Bodart ◽  
Ethan P. Glaser ◽  
Steven M. MacLean ◽  
Meifan A. Chen ◽  
John C. Gensel
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Immune Cells ◽  
Cellular Response ◽  
Tissue Loss ◽  
Mechanical Trauma ◽  
Cell Type ◽  
Therapeutic Implications ◽  
Adaptive Immune Cells ◽  
Cord Injury

Spinal cord injury (SCI) is a life-altering event for which there is no treatment. Depending on injury location and severity, the breadth of the effects can go far past simple mobility. Primary mechanical trauma triggers a variety of secondary cellular events that exacerbate tissue loss as well as facilitate endogenous repair. A large focus of SCI research is on understanding the pathophysiological mechanisms through which these secondary responses contribute to morbidities associated with SCI. Neuroinflammation, a common response to central nervous system (CNS) insult, is central to the secondary injury cascade. In the context of SCI, the inflammatory response plays a contradictory role in recovery; immune cells release both pro- and anti-inflammatory cytokines at the injury site and clear debris while also causing damage to spared tissue. The major innate and adaptive immune cells that respond to SCI are neutrophils, astrocytes, microglia/macrophages, B cells, and T cells. For each cell type, the timing of the cellular response (in both human and rodent models of SCI), the potential role each cell type plays in the pathophysiology of injury, and the therapeutic implications of targeting each cell type for SCI recovery are discussed.

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