scholarly journals Activation of Neuroprotective Microglia and Astrocytes at the Lesion Site and in the Adjacent Segments Is Crucial for Spontaneous Locomotor Recovery after Spinal Cord Injury

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1943
Author(s):  
Alexandra Kisucká ◽  
Katarína Bimbová ◽  
Mária Bačová ◽  
Ján Gálik ◽  
Nadežda Lukáčová
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Lesion Site ◽  
Post Injury ◽  
Reactive Microglia ◽  
Locomotor Recovery ◽  
Cord Injury ◽  
Polarization States ◽  
Anti Inflammatory ◽  
Adjacent Segments

Microglia and astrocytes play an important role in the regulation of immune responses under various pathological conditions. To detect environmental cues associated with the transformation of reactive microglia (M1) and astrocytes (A1) into their polarization states (anti-inflammatory M2 and A2 phenotypes), we studied time-dependent gene expression in naive and injured spinal cord. The relationship between astrocytes and microglia and their polarization states were studied in a rat model after Th9 compression (40g/15 min) in acute and subacute stages at the lesion site, and both cranially and caudally. The gene expression of microglia/macrophages and M1 microglia was strongly up-regulated at the lesion site and caudally one week after SCI, and attenuated after two weeks post-SCI. GFAP and S100B, and A1 astrocytes were profoundly expressed predominantly two weeks post-SCI at lesion site and cranially. Gene expression of anti-inflammatory M2a microglia (CD206, CHICHI, IL1rn, Arg-1), M2c microglia (TGF-β, SOCS3, IL4R α) and A2 astrocytes (Tgm1, Ptx3, CD109) was greatly activated at the lesion site one week post-SCI. In addition, we observed positive correlation between neurological outcome and expression of M2a, M2c, and A2 markers. Our findings indicate that the first week post‑injury is critical for modulation of reactive microglia/astrocytes into their neuroprotective phenotypes.

scholarly journals Unaffected functional recovery after spinal cord contusions at different circadian times

2021 ◽  
Author(s):  
Lukasz Slomnicki ◽  
George Wei ◽  
Darlene Burke ◽  
Scott Whittemore ◽  
Sujata Saraswat Ohri ◽  
...  
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Time Of Day ◽  
Acute Injury ◽  
Spinal Cord Tissue ◽  
Post Injury ◽  
Locomotor Recovery ◽  
Physiological Processes ◽  
Acute Injuries ◽  
Cord Injury

The circadian rhythms of gene expression drive diurnal oscillations of physiological processes that determine the acute injury response including immunity, inflammation and hemostasis. While outcomes of various acute injuries are affected by the time of day at which the original insult occurred, such diurnal influences on recovery after spinal cord injury (SCI) are unknown. We report that several key regulators of circadian gene expression are differentially expressed in uninjured spinal cord tissue of naïve mice at Zeitgeber time 1 (ZT1) or ZT12, where ZT0 or ZT12 are times when lights are turned on or off, respectively. However, mice that received moderate, T9 contusive SCI at ZT0 or ZT12 showed similar recovery of locomotion as determined using the ladder walking test and the Basso mouse scale (BMS) over a 6 week post-injury period. Consistent with those findings, terminal histological analysis revealed no significant differences in white matter sparing at the injury epicenter. Therefore, locomotor recovery after thoracic contusive SCI is not affected by the time of day at which the neurotrauma occurred at least when comparing the beginning to the end of the mouse active period.

scholarly journals Contralateral Axon Sprouting but Not Ipsilateral Regeneration Is Responsible for Spontaneous Locomotor Recovery Post Spinal Cord Hemisection

2021 ◽  
Vol 15 ◽  
Author(s):  
Yudong Cao ◽  
Ya Shi ◽  
Zhifeng Xiao ◽  
Xi Chen ◽  
Bing Chen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Medical Problem ◽  
Contralateral Side ◽  
Neuronal Regeneration ◽  
Lesion Site ◽  
Sprague Dawley ◽  
Locomotor Recovery ◽  
Locomotor Function ◽  
Cord Injury ◽  
Spinal Cord Hemisection

Spinal cord injury (SCI) usually results in permanent functional impairment and is considered a worldwide medical problem. However, both motor and sensory functions can spontaneously recover to varying extents in humans and animals with incomplete SCI. This study observed a significant spontaneous hindlimb locomotor recovery in Sprague-Dawley rats at four weeks after post-right-side spinal cord hemisection at thoracic 8 (T8). To verify whether the above spontaneous recovery derives from the ipsilateral axonal or neuronal regeneration to reconnect the lesion site, we resected either the scar tissue or right side T7 spinal cord at five weeks post-T8 hemisected injury. The results showed that the spontaneously achieved right hindlimb locomotor function had little change after resection. Furthermore, when T7 left hemisection was performed five weeks after the initial injury, the spontaneously achieved right hindlimb locomotor function was dramatically abolished. A similar result could also be observed when T7 transection was performed after the initial hemisection. The results indicated that it might be the contralateral axonal remolding rather than the ipsilateral axonal or neuronal regeneration beyond the lesion site responsible for the spontaneous hindlimb locomotor recovery. The immunostaining analyses and corticospinal tracts (CSTs) tracing results confirmed this hypothesis. We detected no substantial neuronal and CST regeneration throughout the lesion site; however, significantly more CST fibers were observed to sprout from the contralateral side at the lumbar 4 (L4) spinal cord in the hemisection model rats than in intact ones. In conclusion, this study verified that contralateral CST sprouting, but not ipsilateral CST or neuronal regeneration, is primarily responsible for the spontaneous locomotor recovery in hemisection SCI rats.

A Selective P2Y Purinergic Receptor Agonist 2-MesADP Enhances Locomotor Recovery after Acute Spinal Cord Injury

2020 ◽  
Vol 83 (2) ◽  
pp. 195-212
Author(s):  
Ziru Zhao ◽  
Xiao Hu ◽  
Zhourui Wu ◽  
Qi Chen ◽  
Qihui Shao
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Neuronal Apoptosis ◽  
Purinergic Receptor ◽  
Expression Patterns ◽  
Gene Profiling ◽  
Locomotor Recovery ◽  
Wnt Signal Pathway ◽  
Cord Injury

Introduction: Spinal cord injury (SCI) causes most severe motor and sensory dysfunctions. In Chinese traditional medicine, the agonist of a purinergic receptor is believed to have a positive effect on SCIs, and 2-Methylthio-adenosine-5′-diphosphate (2-MesADP) is a selective agonist of the P2Y purinergic receptor. Methods: To investigate its therapeutic function and molecular mechanism in SCI, transcriptome analysis associated with weighted gene co-expression network analysis (WGCNA) was carried out at various time points after T9 crush injury. Results: 2-MesADP demonstrated recovery of limb motor function at the 6 weeks after injury, accompanied by neuronal regeneration and axon remyelination at 2 and 6 weeks. Furthermore, gene profiling revealed alternated gene expression with the treatment of 2-MesADP. These genes were assigned to a total of 38 modules, followed by gene ontology analysis; of these, 18 represented neuronal apoptosis and regeneration, immune response, synaptic transmission, cell cycle, and angiogenesis. In the neuronal apoptosis and regeneration module, Nefh, NeuroD6, and Dcx in the 2-MesADP group were noticed due to their interesting expression pattern. The gene expression patterns of Mag, Mog, and Cnp, which played key roles in myelination, were significantly changed with the treatment of 2-MesADP. Wnt signal pathway was the most important pathway in 2-MesADP treatment for acute SCI. Conclusion: 2-MesADP enhanced locomotor recovery in mouse SCI by altering the expression of neuronal apoptosis and remyelination-related genes and Wnt signaling pathways.

Screening anti-inflammatory compounds in injured spinal cord with microarrays: a comparison of bioinformatics analysis approaches

2004 ◽  
Vol 17 (2) ◽  
pp. 201-214 ◽  
Author(s):  
Jonathan Z. Pan ◽  
Rebecka Jörnsten ◽  
Ronald P. Hart
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Inflammatory Responses ◽  
Expression Profiles ◽  
Slice Culture ◽  
Data Set ◽  
Cord Injury ◽  
In Vivo Testing ◽  
Anti Inflammatory

Inflammatory responses contribute to secondary tissue damage following spinal cord injury (SCI). A potent anti-inflammatory glucocorticoid, methylprednisolone (MP), is the only currently accepted therapy for acute SCI but its efficacy has been questioned. To search for additional anti-inflammatory compounds, we combined microarray analysis with an explanted spinal cord slice culture injury model. We compared gene expression profiles after treatment with MP, acetaminophen, indomethacin, NS398, and combined cytokine inhibitors (IL-1ra and soluble TNFR). Multiple gene filtering methods and statistical clustering analyses were applied to the multi-dimensional data set and results were compared. Our analysis showed a consistent and unique gene expression profile associated with NS398, the selective cyclooxygenase-2 (COX-2) inhibitor, in which the overall effect of these upregulated genes could be interpreted as neuroprotective. In vivo testing demonstrated that NS398 reduced lesion volumes, unlike MP or acetaminophen, consistent with a predicted physiological effect in spinal cord. Combining explanted spinal cultures, microarrays, and flexible clustering algorithms allows us to accelerate selection of compounds for in vivo testing.

scholarly journals Limited changes in locomotor recovery and unaffected white matter sparing after spinal cord contusion at different times of day

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0249981
Author(s):  
Lukasz P. Slomnicki ◽  
George Wei ◽  
Darlene A. Burke ◽  
Emily R. Hodges ◽  
Scott A. Myers ◽  
...  
Keyword(s):  
Spinal Cord ◽  
White Matter ◽  
Time Of Day ◽  
Independent Study ◽  
Post Injury ◽  
Locomotor Recovery ◽  
Acute Injuries ◽  
Cord Injury ◽  
Spinal Cord Contusion ◽  
Blood Spinal Cord Barrier

The circadian gene expression rhythmicity drives diurnal oscillations of physiological processes that may determine the injury response. While outcomes of various acute injuries are affected by the time of day at which the original insult occurred, such influences on recovery after spinal cord injury (SCI) are unknown. We report that mice receiving moderate, T9 contusive SCI at ZT0 (zeitgeber time 0, time of lights on) and ZT12 (time of lights off) showed similar hindlimb function recovery in the Basso mouse scale (BMS) over a 6 week post-injury period. In an independent study, no significant differences in BMS were observed after SCI at ZT18 vs. ZT6. However, the ladder walking test revealed modestly improved performance for ZT18 vs. ZT6 mice at week 6 after injury. Consistent with those minor effects on functional recovery, terminal histological analysis revealed no significant differences in white matter sparing at the injury epicenter. Likewise, blood-spinal cord barrier disruption and neuroinflammation appeared similar when analyzed at 1 week post injury at ZT6 or ZT18. Therefore, locomotor recovery after thoracic contusive SCI is not substantively modulated by the time of day at which the neurotrauma occurred.

scholarly journals Fosl1 Targets AMPK to Inhibit Autophagy-Mediated Anti-Apoptotic and Anti-Inflammatory Effects in Spinal Cord Injury

2020 ◽  
Author(s):  
Lin Zhong ◽  
Sheng Fang ◽  
An-Quan Wang ◽  
Tao Wang ◽  
Wei Huang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Animal Model ◽  
Inflammatory Factor ◽  
Mrna Levels ◽  
Ampk Activation ◽  
Cord Injury ◽  
Anti Inflammatory

Abstract Background: The objective of this study was to delineate the role of Fosl1 in regulating inflammation and apoptosis following spinal cord injury.Methods: GSE45006 datasets from Gene Expression Omnibus (GEO) were explored to analyze Fosl1 gene expression. Next, we established an animal model to assess Fosl1 and AMPK by western blotting, real-time PCR, and immunohistochemical staining and used immunofluorescence staining to check Fosl1 expression in neurons. Fosl1 silencing was used to assess the effect on AMPK, cell viability, autophagy, inflammation and apoptosis. Subsequently, an AMPK activator and inhibitor were added to PC-12 cells with H2O2-induced injury subjected to si-Fosl1 treatment to examine the change in the above indexes and to determine whether the benefits from Fosl1 silencing occurred via AMPK. Moreover, we employed chloroquine (CQ) and rapamycin (RAP) to activate and inhibit autophagy, respectively, and revealed the effects of the upregulation and downregulation of autophagy following AMPK interference. Finally, an animal model was used to identify the effect of si-Fosl1 in vivo.Results: Based on the analysis of the GSE45006 datasets, Fosl1 was found to be highly expressed and was also found to be significantly enhanced in our animal model. Fosl1 knockdown upregulated AMPK at the protein and mRNA levels, promoted autophagic proteins (LC3 II/I, Beclin1) and inhibited inflammatory factors (IL-1β, IL-6, TNF-α) and apoptosis markers (caspase3, Bax). However, Fosl1 decreased the negatively related autophagic protein p62, the anti-inflammatory factor IL-10 and the anti-apoptotic marker Bcl-2. By utilizing compound C (com, an AMPK inhibitor), we learned that AMPK inhibition exhibited unfavorable effects on autophagy but promoted inflammation and apoptosis following Fosl1 silencing. AMPK activation showed contrasting effects. Moreover, we used CQ (an autophagic inhibitor), which indicated that CQ reversed the benefits of AMPK activation on inflammation and apoptosis. The autophagic activator RAP attenuated the negative effects after com treatment. In vivo, si-Fosl1 increased BBB scores at 7 d and 14 d and motor neurons, meanwhile, it decreased the number of apoptotic cells, and inflammatory cytokine expression at 14 d postoperation. Conclusion: Fosl1 can suppress AMPK to promote inflammation and apoptosis through autophagy in SCI.

scholarly journals Lentiviral interleukin-10 gene therapy preserves fine motor circuitry and function after a cervical spinal cord injury in male and female mice

2020 ◽  
Author(s):  
Jessica Y Chen ◽  
Emily J Fu ◽  
Paras R Patel ◽  
Hasan A Sawan ◽  
Kayla A Moss ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Motor Neurons ◽  
Interleukin 10 ◽  
Fine Motor ◽  
Behavioral Recovery ◽  
Post Injury ◽  
Cord Injury ◽  
Muscle Innervation ◽  
Anti Inflammatory

AbstractIn mammals, spinal cord injuries often result in muscle paralysis through the apoptosis of lower motor neurons and denervation of neuromuscular junctions. Previous research shows that the inflammatory response to a spinal cord injury can cause additional tissue damage after the initial trauma. To modulate this inflammatory response, we delivered lentiviral anti-inflammatory interleukin-10, via loading onto an implantable biomaterial scaffold, into a left-sided hemisection at the C5 vertebra in mice. We hypothesized that improved behavioral outcomes associated with anti-inflammatory treatment are due to the sparing of fine motor circuit components. We examined behavioral recovery using a ladder beam, lower motor neuron apoptosis and muscle innervation using histology, and electromyogram recordings using intraspinal optogenetic stimulation at 2 weeks post-injury. Ladder beam analysis shows interleukin-10 treatment results in significant improvement of behavioral recovery at 2 and 12 weeks post-injury when compared to mice treated with a control virus. Histology shows interleukin-10 results in greater numbers of lower motor neurons and muscle innervation at 2 weeks post-injury. Furthermore, electromyogram recordings suggest that interleukin-10-treated animals have signal-to-noise ratios and peak-to-peak amplitudes more similar to that of uninjured controls than to that of control injured animals at 2 weeks post-injury. These data show that gene therapy using anti-inflammatory interleukin-10 can significantly reduce lower motor neuron loss, muscle denervation, and subsequent motor deficits after a spinal cord injury. Together, these results suggest that early modulation of the injury response can preserve muscle function with long-lasting benefits.

scholarly journals IL-10 lentivirus-laden hydrogel tubes increase spinal progenitor survival and neuronal differentiation after spinal cord injury

2021 ◽  
Author(s):  
Andrew Ciciriello ◽  
Dominique Smith ◽  
Mary Munsell ◽  
Sydney Boyd ◽  
Lonnie Shea ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Stem Cell ◽  
Synergistic Effects ◽  
Post Transplantation ◽  
Post Injury ◽  
Axon Elongation ◽  
Cord Injury ◽  
Delivery Platform ◽  
Anti Inflammatory

The pathophysiological response following spinal cord injury (SCI) is characterized by a complex cellular cascade that limits regeneration. Biomaterial and stem cell combination therapies have shown synergistic effects, compared to their interventions independent of each other, and represent a promising approach towards regaining function after injury. In this study, we combine our polyethylene glycol (PEG) cell delivery platform with lentiviral-mediated overexpression of the anti-inflammatory cytokine interleukin (IL)-10 to improve embryonic day 14 (E14) spinal progenitor transplant survival. PEG tubes loaded with lentivirus encoding for IL-10 were implanted immediately following injury into a mouse SCI hemisection model. Two weeks after tube implantation, mouse E14 spinal progenitors were injected directly into the integrated tubes, which served as a soft substrate for cell transplantation. Together, the tubes with the IL-10 encoding lentivirus improved E14 spinal progenitor survival, assessed at two weeks post-transplantation (four weeks post-injury). Mice receiving IL-10 lentivirus-laden tubes had on average 8.1% of E14 spinal progenitors survive compared to 0.7% in mice receiving transplants without tubes, an 11.5-fold difference. Surviving E14 spinal progenitors gave rise to neurons when injected into tubes. Additionally, axon elongation and remyelination was observed, in addition to a faster rate of functional recovery in mice receiving anti-inflammatory tubes with E14 spinal progenitor delivery. This system affords increased control over the transplantation microenvironment, offering the potential to improve stem cell-mediated tissue regeneration.

scholarly journals Transcriptional profiling of non-injured nociceptors after spinal cord injury reveals diverse molecular changes

2019 ◽  
Author(s):  
Jessica R. Yasko ◽  
Isaac L. Moss ◽  
Richard E. Mains
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Chronic Pain ◽  
Signaling Pathways ◽  
Sensory Neurons ◽  
Traumatic Spinal Cord Injury ◽  
Post Injury ◽  
Inflammatory Signaling ◽  
Cord Injury

AbstractTraumatic spinal cord injury (SCI) has devastating implications for patients, including a high predisposition for developing chronic pain distal to the site of injury. Chronic pain develops weeks to months after injury, consequently patients are treated after irreparable changes have occurred. Nociceptors are central to chronic pain; however, the diversity of this cellular population presents challenges to understanding mechanisms and attributing pain modalities to specific cell types. To begin to address how peripheral sensory neurons distal to the site of injury may contribute to the below-level pain reported by SCI patients, we examined SCI-induced changes in gene expression in lumbar dorsal root ganglia (DRG) below the site of injury. SCI was performed at the T10 vertebral level, with injury produced by a vessel clip with a closing pressure of 15g for 1 minute. Alterations in gene expression produce long-term sensory changes, therefore we were interested in studying SCI-induced transcripts before the onset of chronic pain, which may trigger changes in downstream signaling pathways and ultimately facilitate the transmission of pain. To examine changes in the nociceptor subpopulation in DRG distal to the site of injury, we retrograde labeled sensory neurons projecting to the hairy hindpaw skin with fluorescent dye and collected the corresponding lumbar (L2-L6) DRG 4 days post-injury. Following dissociation, labeled neurons were purified by fluorescence-activated cell sorting. RNA was extracted from sorted sensory neurons of naïve, sham, or SCI mice and sequenced. Transcript abundances validated that the desired population of nociceptors were isolated. Cross-comparisons to data sets from similar studies confirmed we were able to isolate our cells of interest and identify a unique pattern of gene expression within a subpopulation of neurons projecting to the hairy hindpaw skin. Differential gene expression analysis showed high expression levels and significant transcript changes 4 days post-injury in SCI cell populations relevant to the onset of chronic pain. Regulatory interrelationships predicted by pathway analysis implicated changes within the synaptogenesis signaling pathway as well as networks related to inflammatory signaling mechanisms, suggesting a role for synaptic plasticity and a correlation with pro-inflammatory signaling in the transition from acute to chronic pain.Contribution to the fieldTraumatic spinal cord injury (SCI) has devastating implications for patients, including a high predisposition for developing chronic pain. Much of the pain seems to emanate from tissues further away from the brain than the site of injury. Chronic pain develops weeks to months after injury, which means that patients are frequently treated only after enduring pain has developed. Nociceptors are the specialized sensory neurons central to chronic pain. We were interested in studying SCI-induced gene transcript (RNA) changes before the onset of chronic pain, in the hope of identifying mechanisms which could become therapeutic targets. Nociceptors below the site of spinal injury were isolated and their RNAs were sequenced. The results identified a unique pattern of gene expression in the subpopulation of nociceptors projecting to the relevant peripheral tissue. Particularly interesting were sets of genes crucial to synapse formation and maturation – the ability of neurons to talk to each other – and genes involved in inflammatory responses, since treatment of inflammation of nervous tissue could also be important for therapeutic approaches. It is evident that the transition from acute to chronic pain occurs in distinct steps that involve numerous signaling pathways, providing a host of potential new drug targets.

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.

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