scholarly journals Genes and miRNAs as Hurdles and Promoters of Corticospinal Tract Regeneration in Spinal Cord Injury

2021 ◽  
Vol 9 ◽  
Author(s):  
Marina Boido ◽  
Alessandro Vercelli
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Axonal Regeneration ◽  
Chronic Phase ◽  
Axon Growth ◽  
Glial Scar ◽  
Neural Regeneration ◽  
Axonal Regrowth ◽  
Cord Injury ◽  
Sensory Motor

Spinal cord injury (SCI) is a devastating lesion to the spinal cord, which determines the interruption of ascending/descending axonal tracts, the loss of supraspinal control of sensory-motor functions below the injured site, and severe autonomic dysfunctions, dramatically impacting the quality of life of the patients. After the acute inflammatory phase, the progressive formation of the astrocytic glial scar characterizes the acute-chronic phase: such scar represents one of the main obstacles to the axonal regeneration that, as known, is very limited in the central nervous system (CNS). Unfortunately, a cure for SCI is still lacking: the current clinical approaches are mainly based on early vertebral column stabilization, anti-inflammatory drug administration, and rehabilitation programs. However, new experimental therapeutic strategies are under investigation, one of which is to stimulate axonal regrowth and bypass the glial scar. One major issue in axonal regrowth consists of the different genetic programs, which characterize axonal development and maturation. Here, we will review the main hurdles that in adulthood limit axonal regeneration after SCI, describing the key genes, transcription factors, and miRNAs involved in these processes (seen their reciprocal influencing action), with particular attention to corticospinal motor neurons located in the sensory-motor cortex and subjected to axotomy in case of SCI. We will highlight the functional complexity of the neural regeneration programs. We will also discuss if specific axon growth programs, that undergo a physiological downregulation during CNS development, could be reactivated after a spinal cord trauma to sustain regrowth, representing a new potential therapeutic approach.

scholarly journals The Biology of Regeneration Failure and Success After Spinal Cord Injury

2018 ◽  
Vol 98 (2) ◽  
pp. 881-917 ◽  
Author(s):  
Amanda Phuong Tran ◽  
Philippa Mary Warren ◽  
Jerry Silver
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Functional Recovery ◽  
Axonal Regeneration ◽  
Molecular Mechanisms ◽  
Glial Scar ◽  
Perineuronal Net ◽  
Physical Trauma ◽  
Axonal Regrowth ◽  
Cord Injury

Since no approved therapies to restore mobility and sensation following spinal cord injury (SCI) currently exist, a better understanding of the cellular and molecular mechanisms following SCI that compromise regeneration or neuroplasticity is needed to develop new strategies to promote axonal regrowth and restore function. Physical trauma to the spinal cord results in vascular disruption that, in turn, causes blood-spinal cord barrier rupture leading to hemorrhage and ischemia, followed by rampant local cell death. As subsequent edema and inflammation occur, neuronal and glial necrosis and apoptosis spread well beyond the initial site of impact, ultimately resolving into a cavity surrounded by glial/fibrotic scarring. The glial scar, which stabilizes the spread of secondary injury, also acts as a chronic, physical, and chemo-entrapping barrier that prevents axonal regeneration. Understanding the formative events in glial scarring helps guide strategies towards the development of potential therapies to enhance axon regeneration and functional recovery at both acute and chronic stages following SCI. This review will also discuss the perineuronal net and how chondroitin sulfate proteoglycans (CSPGs) deposited in both the glial scar and net impede axonal outgrowth at the level of the growth cone. We will end the review with a summary of current CSPG-targeting strategies that help to foster axonal regeneration, neuroplasticity/sprouting, and functional recovery following SCI.

scholarly journals Importance of the vasculature in cyst formation after spinal cord injury

2009 ◽  
Vol 11 (4) ◽  
pp. 432-437 ◽  
Author(s):  
Gemma E. Rooney ◽  
Toshiki Endo ◽  
Syed Ameenuddin ◽  
Bingkun Chen ◽  
Sandeep Vaishya ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Axonal Regeneration ◽  
Cyst Formation ◽  
Glial Scar ◽  
Scar Formation ◽  
Cystic Formation ◽  
Dural Closure ◽  
Surgical Methods ◽  
Cord Injury

Object Glial scar and cystic formation greatly contribute to the inhibition of axonal regeneration after spinal cord injury (SCI). Attempts to promote axonal regeneration are extremely challenging in this type of hostile environment. The objective of this study was to examine the surgical methods that may be used to assess the factors that influence the level of scar and cystic formation in SCI. Methods In the first part of this study, a complete transection was performed at vertebral level T9–10 in adult female Sprague-Dawley rats. The dura mater was either left open (control group) or was closed using sutures or hyaluronic acid. In the second part of the study, complete or subpial transection was performed, with the same dural closure technique applied to both groups. Histological analysis of longitudinal sections of the spinal cord was performed, and the percentage of scar and cyst formation was determined. Results Dural closure using sutures resulted in significantly less glial scar formation (p = 0.0248), while incorporation of the subpial transection surgical technique was then shown to significantly decrease cyst formation (p < 0.0001). Conclusions In this study, the authors demonstrated the importance of the vasculature in cyst formation after spinal cord trauma and confirmed the importance of dural closure in reducing glial scar formation.

scholarly journals Extrinsic and Intrinsic Regulation of Axon Regeneration by MicroRNAs after Spinal Cord Injury

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Ping Li ◽  
Zhao-Qian Teng ◽  
Chang-Mei Liu
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Axonal Regeneration ◽  
Axon Regeneration ◽  
Therapeutic Potential ◽  
Glial Scar ◽  
Scar Formation ◽  
Extrinsic Factors ◽  
Cord Injury ◽  
The Central Nervous System

Spinal cord injury is a devastating disease which disrupts the connections between the brain and spinal cord, often resulting in the loss of sensory and motor function below the lesion site. Most injured neurons fail to regenerate in the central nervous system after injury. Multiple intrinsic and extrinsic factors contribute to the general failure of axonal regeneration after injury. MicroRNAs can modulate multiple genes’ expression and are tightly controlled during nerve development or the injury process. Evidence has demonstrated that microRNAs and their signaling pathways play important roles in mediating axon regeneration and glial scar formation after spinal cord injury. This article reviews the role and mechanism of differentially expressed microRNAs in regulating axon regeneration and glial scar formation after spinal cord injury, as well as their therapeutic potential for promoting axonal regeneration and repair of the injured spinal cord.

scholarly journals Taurine promotes axonal regeneration after a complete spinal cord injury in lampreys

2019 ◽  
Author(s):  
Daniel Sobrido-Cameán ◽  
Blanca Fernández-López ◽  
Natividad Pereiro ◽  
Anunciación Lafuente ◽  
María Celina Rodicio ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Axonal Regeneration ◽  
Axon Regeneration ◽  
Traumatic Event ◽  
Axonal Regrowth ◽  
Cord Injury ◽  
Taurine Treatment ◽  
Complete Spinal Cord Injury ◽  
The Brain

AbstractTaurine is one of the most abundant free amino acids in the brain. It is well known that taurine protects the brain from further damage after a traumatic event. However, only a few ex vivo studies have looked at the possible role of taurine in the regulation of axon regeneration after injury. Here, we aimed to reveal the possible role for taurine in the modulation of axonal regeneration following a complete spinal cord injury (SCI) using lampreys as an animal model. The brainstem of lampreys contains several individually identifiable descending neurons that differ greatly in their capacity for axonal regeneration after SCI. This offers a convenient model to promote or inhibit axonal regrowth in the same in vivo preparation. First, we carried out high performance liquid chromatography experiments to measure taurine levels in the spinal cord following SCI. Our results revealed a statistically significant increase in taurine levels 4 weeks post lesion, which suggested that taurine might have a positive effect on axonal regrowth. Based on these results, we decided to apply an acute taurine treatment at the site of injury to study its effect on axon regeneration. Results from these experiments show that an acute taurine treatment enhances axonal regeneration following SCI in lampreys. This offers a novel way to try to promote axon regeneration after nervous system injuries in mammalian models.

scholarly journals miR-7b-3p Exerts a Dual Role After Spinal Cord Injury, by Supporting Plasticity and Neuroprotection at Cortical Level

2021 ◽  
Vol 8 ◽  
Author(s):  
Matilde Ghibaudi ◽  
Marina Boido ◽  
Darrell Green ◽  
Elena Signorino ◽  
Gaia Elena Berto ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Axon Growth ◽  
Dual Role ◽  
Neural Regeneration ◽  
Developmental Phase ◽  
Apoptotic Pathway ◽  
Cord Injury

Spinal cord injury (SCI) affects 6 million people worldwide with no available treatment. Despite research advances, the inherent poor regeneration potential of the central nervous system remains a major hurdle. Small RNAs (sRNAs) 19–33 nucleotides in length are a set of non-coding RNA molecules that regulate gene expression and have emerged as key players in regulating cellular events occurring after SCI. Here we profiled a class of sRNA known as microRNAs (miRNAs) following SCI in the cortex where the cell bodies of corticospinal motor neurons are located. We identified miR-7b-3p as a candidate target given its significant upregulation after SCI in vivo and we screened by miRWalk PTM the genes predicted to be targets of miR-7b-3p (among which we identified Wipf2, a gene regulating neurite extension). Moreover, 16 genes, involved in neural regeneration and potential miR-7b-3p targets, were found to be downregulated in the cortex following SCI. We also analysed miR-7b-3p function during cortical neuron development in vitro: we observed that the overexpression of miR-7b-3p was important (1) to maintain neurons in a more immature and, likely, plastic neuronal developmental phase and (2) to contrast the apoptotic pathway; however, in normal conditions it did not affect the Wipf2 expression. On the contrary, the overexpression of miR-7b-3p upon in vitro oxidative stress condition (mimicking the SCI environment) significantly reduced the expression level of Wipf2, as observed in vivo, confirming it as a direct miR-7b-3p target. Overall, these data suggest a dual role of miR-7b-3p: (i) the induction of a more plastic neuronal condition/phase, possibly at the expense of the axon growth, (ii) the neuroprotective role exerted through the inhibition of the apoptotic cascade. Increasing the miR-7b-3p levels in case of SCI could reactivate in adult neurons silenced developmental programmes, supporting at the same time the survival of the axotomised neurons.

Schwann cell transplantation for spinal cord injury repair: its significant therapeutic potential and prospectus

2015 ◽  
Vol 26 (2) ◽  
Author(s):  
Haruo Kanno ◽  
Damien D. Pearse ◽  
Hiroshi Ozawa ◽  
Eiji Itoi ◽  
Mary Bartlett Bunge
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Functional Recovery ◽  
Axonal Regeneration ◽  
Therapeutic Strategy ◽  
Glial Scar ◽  
Scar Formation ◽  
Tissue Loss ◽  
Injured Spinal Cord ◽  
Cord Injury

AbstractTransplantation of Schwann cells (SCs) is a promising therapeutic strategy for spinal cord repair. The introduction of SCs into the injured spinal cord has been shown to reduce tissue loss, promote axonal regeneration, and facilitate myelination of axons for improved sensorimotor function. The pathology of spinal cord injury (SCI) comprises multiple processes characterized by extensive cell death, development of a milieu inhibitory to growth, and glial scar formation, which together limits axonal regeneration. Many studies have suggested that significant functional recovery following SCI will not be possible with a single therapeutic strategy. The use of additional approaches with SC transplantation may be needed for successful axonal regeneration and sufficient functional recovery after SCI. An example of such a combination strategy with SC transplantation has been the complementary administration of neuroprotective agents/growth factors, which improves the effect of SCs after SCI. Suspension of SCs in bioactive matrices can also enhance transplanted SC survival and increase their capacity for supporting axonal regeneration in the injured spinal cord. Inhibition of glial scar formation produces a more permissive interface between the SC transplant and host spinal cord for axonal growth. Co-transplantation of SCs and other types of cells such as olfactory ensheathing cells, bone marrow mesenchymal stromal cells, and neural stem cells can be a more effective therapy than transplantation of SCs alone following SCI. This article reviews some of the evidence supporting the combination of SC transplantation with additional strategies for SCI repair and presents a prospectus for achieving better outcomes for persons with SCI.

scholarly journals A Mathematical Model of Regenerative Axon Growing along Glial Scar after Spinal Cord Injury

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Xuning Chen ◽  
Weiping Zhu
Keyword(s):  
Mathematical Model ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Average Rate ◽  
Three Dimensional ◽  
Simulated Data ◽  
Axon Growth ◽  
Glial Scar ◽  
Factors Affecting ◽  
Cord Injury

A major factor in the failure of central nervous system (CNS) axon regeneration is the formation of glial scar after the injury of CNS. Glial scar generates a dense barrier which the regenerative axons cannot easily pass through or by. In this paper, a mathematical model was established to explore how the regenerative axons grow along the surface of glial scar or bypass the glial scar. This mathematical model was constructed based on the spinal cord injury (SCI) repair experiments by transplanting Schwann cells as bridge over the glial scar. The Lattice Boltzmann Method (LBM) was used in this model for three-dimensional numerical simulation. The advantage of this model is that it provides a parallel and easily implemented algorithm and has the capability of handling complicated boundaries. Using the simulated data, two significant conclusions were made in this study:(1)the levels of inhibitory factors on the surface of the glial scar are the main factors affecting axon elongation and(2)when the inhibitory factor levels on the surface of the glial scar remain constant, the longitudinal size of the glial scar has greater influence on the average rate of axon growth than the transverse size. These results will provide theoretical guidance and reference for researchers to design efficient experiments.

scholarly journals Plant Scaffolds Support Motor Recovery and Regeneration in Rats after Traumatic Spinal Cord Injury

2020 ◽  
Author(s):  
Daniel J. Modulevsky ◽  
Charles M. Cuerrier ◽  
Maxime Leblanc-Latour ◽  
Ryan J. Hickey ◽  
Ras-Jeevan K. Obhi ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Motor Function ◽  
Neural Regeneration ◽  
Plant Tissues ◽  
Traumatic Spinal Cord Injury ◽  
Spinal Cord Tissue ◽  
Vascular Bundles ◽  
Axonal Regrowth ◽  
Cord Injury

ABSTRACTAs of yet, no standard of care incorporates the use of a biomaterial to treat traumatic spinal cord injury (SCI)1–5. However, intense development of biomaterials for treating SCI have focused on the fabrication of microscale channels to support the regrowth of axons while minimizing scar tissue formation6–10. We previously demonstrated that plant tissues can be decellularized and processed to form sterile, biocompatible and implantable biomaterials that support cell infiltration and vascularization in vivo11–13. Notably, the vascular bundles of plant tissues are also composed of microscale channels with geometries thought to be relevant for supporting neural tissue regeneration9,14. We hypothesized that decellularized vascular bundles would support neural regeneration and the recovery of motor function. Therefore, rats which received a complete T8-T9 spinal cord transection were implanted with plant-derived channeled scaffolds. Animals which received the scaffolds alone, with no therapeutic stem cells or other interventions, demonstrated a significant and stable improvement in motor function over six months compared to controls. Histological analysis reveals minimal scarring and axonal regrowth through the scaffolds, further confirmed with tracer studies. Taken together, our work defines a novel route for exploiting naturally occurring plant microarchitectures to support the repair of functional spinal cord tissue.

Glial scar and neuroregeneration: histological, functional, and magnetic resonance imaging analysis in chronic spinal cord injury

2010 ◽  
Vol 13 (2) ◽  
pp. 169-180 ◽  
Author(s):  
Rong Hu ◽  
Jianjun Zhou ◽  
Chunxia Luo ◽  
Jiangkai Lin ◽  
Xianrong Wang ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Mr Imaging ◽  
Rating Scale ◽  
Time Window ◽  
Critical Time ◽  
Glial Scar ◽  
Electrophysiological Recording ◽  
Axonal Regrowth ◽  
Cord Injury

Object A glial scar is thought to be responsible for halting neuroregeneration following spinal cord injury (SCI). However, little quantitative evidence has been provided to show the relationship of a glial scar and axonal regrowth after injury. Methods In this study performed in rats and dogs, a traumatic SCI model was made using a weight-drop injury device, and tissue sections were stained with H & E for immunohistochemical analysis. The function and behavior of model animals were tested using electrophysiological recording and the Basso-Beattie-Bresnahan Locomotor Rating Scale, respectively. The cavity in the spinal cord after SCI in dogs was observed using MR imaging. Results The morphological results showed that the formation of an astroglial scar was defined at 4 weeks after SCI. While regenerative axons reached the vicinity of the lesion site, the glial scar blocked the extension of regrown axons. In agreement with these findings, the electrophysiological, behavioral, and in vivo MR imaging tests showed that functional recovery reached a plateau at 4 weeks after SCI. The thickness of the glial scars in the injured rat spinal cords was also measured. The mean thickness of the glial scar rostral and caudal to the lesion cavity was 107.00 ± 20.12 μm; laterally it was 69.92 ± 15.12 μm. Conclusions These results provide comprehensive evidence indicating that the formation of a glial scar inhibits axonal regeneration at 4 weeks after SCI. This study reveals a critical time window of postinjury recovery and a detailed spatial orientation of glial scar, which would provide an important basis for the development of therapeutic strategy for glial scar ablation.

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