scholarly journals Microglia-Derived Exosomes Improve Spinal Cord Functional Recovery after Injury via Inhibiting Oxidative Stress and Promoting the Survival and Function of Endothelia Cells

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Wei Peng ◽  
Liyang Wan ◽  
Zixiang Luo ◽  
Yong Xie ◽  
Yudong Liu ◽  
...  

Traumatic spinal cord injury (SCI) is a devastating disease of the central nervous system with long-term disability and high mortality worldwide. Revascularization following SCI provides nutritional supports to rebuild and maintain the homeostasis of neuronal networks, and the subsequent promotion of angiogenesis is beneficial for functional recovery. Oxidative stress drastically produced following SCI has been contributed to endothelial dysfunction and the limited endogenous repair of microvasculature. Recently, exosomes, being regarded as potential therapeutic candidates for many kinds of diseases, have attracted great attentions due to its high bioavailability, safety, and stability. Microglia have been reported to exhibit proangiogenic function and guide the forming of vasculature during tissue repair. However, the specific role of microglia-derived exosomes (MG-Exos) played in SCI is still largely unknown. In the present study, we aimed to evaluate whether MG-Exos could protect spinal cord microvascular endothelial cells (SCMECs) against the toxic effects of oxidative stress, thus promote SCMECs’ survival and function. We also investigated the protective effects of MG-Exos in the mouse model of SCI to verify their capability. Our results demonstrated that MG-Exo treatment significantly decreased the level of oxidative stress (ROS), as well as did the protein levels of NOX2 when bEnd.3 cells were exposed to H2O2-induced oxidative stress in vitro and in vivo. Functional assays showed that MG-Exos could improve the survival and the ability of tube formation and migration in H2O2-induced bEnd.3 in vitro. Moreover, MG-Exos exhibited the positive effects on vascular regeneration and cell proliferation, as well as functional recovery, in the mouse model of SCI. Mechanically, the keap1/Nrf2/HO-1 signaling pathway was also investigated in order to unveil its molecular mechanism, and the results showed that MG-Exos could increase the protein levels of Nrf2 and HO-1 via inhibiting the keap1; they also triggered the expression of its downstream antioxidative-related genes, such as NQo1, Gclc, Cat, and Gsx1. Our findings indicated that MG-Exos exerted an antioxidant effect and positively modulated vascular regeneration and neurological functional recovery post-SCI by activating keap1/Nrf2/HO-1 signaling.

2021 ◽  
Vol 2021 ◽  
pp. 1-27
Author(s):  
Hengshuo Hu ◽  
Nan Xia ◽  
Jiaquan Lin ◽  
Daoyong Li ◽  
Chuanjie Zhang ◽  
...  

Spinal cord injury (SCI) is a traumatic disease that can cause severe nervous system dysfunction. SCI often causes spinal cord mitochondrial dysfunction and produces glucose metabolism disorders, which affect neuronal survival. Zinc is an essential trace element in the human body and plays multiple roles in the nervous system. This experiment is intended to evaluate whether zinc can regulate the spinal cord and neuronal glucose metabolism and promote motor functional recovery after SCI. Then we explore its molecular mechanism. We evaluated the function of zinc from the aspects of glucose uptake and the protection of the mitochondria in vivo and in vitro. The results showed that zinc elevated the expression level of GLUT4 and promoted glucose uptake. Zinc enhanced the expression of proteins such as PGC-1α and NRF2, reduced oxidative stress, and promoted mitochondrial production. In addition, zinc decreased neuronal apoptosis and promoted the recovery of motor function in SCI mice. After administration of AMPK inhibitor, the therapeutic effect of zinc was reversed. Therefore, we concluded that zinc regulated the glucose metabolism of the spinal cord and neurons and promoted functional recovery after SCI through the AMPK pathway, which is expected to become a potential treatment strategy for SCI.


2021 ◽  
Author(s):  
Haojie Zhang ◽  
Chenyu Wu ◽  
Jin-Feng Huang ◽  
Yanlin Chen ◽  
Wen-Fei Ni

Abstract Background: Spinal cord injury (SCI) is a serious injury that can lead to irreversible motor dysfunction and subsequently result in disability and even death. Due to its complicated pathogenic mechanism, there are no effective drug treatments. Piperine, a natural active alkaloid extracted from black pepper, suppressed inflammation in a previous study. The aim of this study was to investigate the therapeutic effect of piperine in a spinal cord injury model.Methods: Spinal cord injury was induced in C57BL/6 mice by clamping the spinal cord with a vascular clip (15 g force; Oscar) for 1 min. Eighty mice were divided randomly into the following four groups: The Sham group (n = 20), the SCI+Vehicle group (n = 20), the SCI+ Piperine group (n = 20), and the SCI+ Piperine+3MA group (n = 20). Before SCI and every 2 days post-SCI, evaluations of the Basso mouse scale (BMS) were performed. On day 14 after SCI, inclined plane tests and footprint analyses were performed. On postoperative day 3, the spinal cord was harvested to assess pyroptosis, reactive oxygen species (ROS), inflammation, and autophagy. Qualitative or quantitative analysis of the components of these potential mechanisms was performed by Western blotting (WB), immunofluorescence (IF), quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA).Results: Piperine enhanced the functional recovery of spinal cord injury. Additionally, piperine inhibited inflammation, attenuated oxidative stress and pyroptosis, and activated autophagy. However, the effects of piperine on the functional recovery of SCI, ROS-mediated autophagy, inflammation and pyroptosis were reversed by the inhibition of autophagy.Conclusions: Our experiments demonstrated that piperine facilitated the functional recovery of spinal cord injury by inhibiting the inflammatory response, oxidative stress and pyroptosis, which are mediated by the activation of autophagy.


2011 ◽  
Vol 105 (2) ◽  
pp. 731-748 ◽  
Author(s):  
Katherine C. Murray ◽  
Marilee J. Stephens ◽  
Edmund W. Ballou ◽  
Charles J. Heckman ◽  
David J. Bennett

Immediately after spinal cord injury (SCI), a devastating paralysis results from the loss of brain stem and cortical innervation of spinal neurons that control movement, including a loss of serotonergic (5-HT) innervation of motoneurons. Over time, motoneurons recover from denervation and function autonomously, exhibiting large persistent calcium currents (Ca PICs) that both help with functional recovery and contribute to uncontrolled muscle spasms. Here we systematically evaluated which 5-HT receptor subtypes influence PICs and spasms after injury. Spasms were quantified by recording the long-lasting reflexes (LLRs) on ventral roots in response to dorsal root stimulation, in the chronic spinal rat, in vitro. Ca PICs were quantified by intracellular recording in synaptically isolated motoneurons. Application of agonists selective to 5-HT2B and 5-HT2C receptors (including BW723C86) significantly increased the LLRs and associated Ca PICs, whereas application of agonists to 5-HT1, 5-HT2A, 5-HT3, or 5-HT4/5/6/7 receptors (e.g., 8-OH-DPAT) did not. The 5-HT2 receptor agonist–induced increases in LLRs were dose dependent, with doses for 50% effects (EC50) highly correlated with published doses for agonist receptor binding ( Ki) at 5-HT2B and 5-HT2C receptors. Application of selective antagonists to 5-HT2B (e.g., RS127445) and 5-HT2C (SB242084) receptors inhibited the agonist-induced increase in LLR. However, antagonists that are known to specifically be neutral antagonists at 5-HT2B/C receptors (e.g., RS127445) had no effect when given by themselves, indicating that these receptors were not activated by residual 5-HT in the spinal cord. In contrast, inverse agonists (such as SB206553) that block constitutive activity at 5-HT2B or 5-HT2C receptors markedly reduced the LLRs, indicating the presence of constitutive activity in these receptors. 5-HT2B or 5-HT2C receptors were confirmed to be on motoneurons by immunolabeling. In summary, 5-HT2B and 5-HT2C receptors on motoneurons become constitutively active after injury and ultimately contribute to recovery of motoneuron function and emergence of spasms.


2020 ◽  
Vol 29 ◽  
pp. 096368972091617 ◽  
Author(s):  
Zhengchao Gao ◽  
Yingjie Zhao ◽  
Xijing He ◽  
Zikuan Leng ◽  
Xiaoqian Zhou ◽  
...  

MicroRNAs (miRNAs) function as gene expression switches, and participate in diverse pathophysiological processes of spinal cord injury (SCI). Olfactory ensheathing cells (OECs) can alleviate pathological injury and facilitate functional recovery after SCI. However, the mechanisms by which OECs restore function are not well understood. This study aims to determine whether silencing miR-199a-5p would enhance the beneficial effects of the OECs. In this study, we measured miR-199a-5p levels in rat spinal cords with and without injury, with and without OEC transplants. Then, we transfected OECs with the sh-miR-199a-5p lentiviral vector to reduce miR-199a-5p expression and determined the effects of these OECs in SCI rats by Basso–Beattie–Bresnahan (BBB) locomotor scores, diffusion tensor imaging (DTI), and histological methods. We used western blotting to measure protein levels of Slit1, Robo2, and srGAP2. Finally, we used the dual-luciferase reporter assay to assess the relationship between miR-199-5p and Slit1, Robo2, and srGAP2 expression. We found that SCI significantly increased miR-199a-5p levels ( P < 0.05), and OEC transplants significantly reduced miR-199a-5p expression ( P < 0.05). Knockdown of miR-199a-5p in OECs had a better therapeutic effect on SCI rats, indicated by higher BBB scores and fractional anisotropy values on DTI, as well as histological findings. Reducing miR-199a-5p levels in transplanted OECs markedly increased spinal cord protein levels of Slit1, Robo2, and srGAP2. Our results demonstrated that transplantation of sh-miR-199a-5p-modified OECs promoted functional recovery in SCI rats, suggesting that miR-199a-5p knockdown was more beneficial to the therapeutic effects of OEC transplants. These findings provided new insights into miRNAs-mediated therapeutic mechanisms of OECs, which helps us to develop therapeutic strategies based on miRNAs and optimize cell therapy for SCI.


2013 ◽  
Vol 2013 ◽  
pp. 1-32 ◽  
Author(s):  
Jun Li ◽  
Guilherme Lepski

Cell transplantation, as a therapeutic intervention for spinal cord injury (SCI), has been extensively studied by researchers in recent years. A number of different kinds of stem cells, neural progenitors, and glial cells have been tested in basic research, and most have been excluded from clinical studies because of a variety of reasons, including safety and efficacy. The signaling pathways, protein interactions, cellular behavior, and the differentiated fates of experimental cells have been studiedin vitroin detail. Furthermore, the survival, proliferation, differentiation, and effects on promoting functional recovery of transplanted cells have also been examined in different animal SCI models. However, despite significant progress, a “bench to bedside” gap still exists. In this paper, we comprehensively cover publications in the field from the last years. The most commonly utilized cell lineages were covered in this paper and specific areas covered include survival of grafted cells, axonal regeneration and remyelination, sensory and motor functional recovery, and electrophysiological improvements. Finally we also review the literature on thein vivotracking techniques for transplanted cells.


2020 ◽  
Author(s):  
Geng Wu ◽  
Herui Liu ◽  
Mei Zhu ◽  
Yang Wu ◽  
Yunlong Bai ◽  
...  

Abstract Background: Bone marrow mesenchymal stem cells (BMSCs) transplantation offers an attractive strategy for treating multiply neurological diseases. Neuregulin1 (NRG1) plays fundamental roles in nervous system development and nerve repair. In this study, we aimed to investigate whether transplantation of NRG1-overexpressing BMSCs could alleviate spinal cord injury (SCI), and to explore the possible underling mechanisms. Methods: In vitro, NRG1-overexpressing BMSCs were constructed via plasmid transfection, and co-cultured with PC12 cells subjected to oxygen-glucose deprivation (OGD). Neurite outgrowth, cell viability and apoptosis of PC12 cells were evaluated. In vivo, BMSCs, empty-vector BMSCs and NRG1-overexpressing BMSCs were transplanted respectively into rats with SCI. Rat locomotor functions, neuronal chromatolysis, neurite outgrowth and cell apoptosis were assessed respectively. Results: The results showed that NRG1-overexpressing BMSCs in vitro significantly expedited neurite growth, elevated growth-associated protein 43 expression, enhanced cell viability and rescued ODG-induced apoptosis in PC12 cells. In vivo, transplantation of NRG1-overexpressing BMSCs notably accelerated rat motor functional recovery, attenuated neuronal chromatolysis, promoted neurite outgrowth and reduced cell apoptosis after SCI. Moreover, NRG1-overexpressing BMSCs were also able to regulate apoptosis-related proteins expression after SCI. Conclusions: These findings demonstrate that NRG1-overexpressing BMSCs can accelerate motor functional recovery by facilitating neurite outgrowth and reducing cell apoptosis after SCI, suggesting that NRG1-overexpressing BMSCs may be a promising candidate for the treatment of SCI.


2020 ◽  
Author(s):  
Yong Cao ◽  
Xu Yan ◽  
Chunyuan Chen ◽  
Hui Xie ◽  
Hongbin Lu ◽  
...  

Abstract Background: Spinal cord injury is a devastating clinical condition for which there are currently no effective therapeutic options. In the present study, we aim to investigate the effect of an administered injection of exosomes derived human urine stem cell (USC-Exo) embedded in hydrogel could improve the spinal cord functional recovery after injury and the underlying mechanism.Methods: Exosome were isolate from USC and identified by transmission electron Microscopy (TEM) and western blot. Functional assays in vitro were performed to assess the effects of USC-Exo on tube formation and migration, as well as their regulatory role in the PI3K/AKT signaling pathway activation. A locally administered injection of exosome embedded in hydrogel was used for SCI treatment. The effects of USC-Exo on functional recovery and the role of the candidate protein ANGPTL3 harboring in USC-Exo for promoting angiogenesis in SCI model was assessed.Results: In the current study, we demonstrate that a locally administered injection of USC-Exo embedded in hydrogel can pass the spinal cord blood brain barrier and deliver ANGPTL3 to the injured spinal cord region. In addition, the administration of human USC-Exo could enhance spinal cord neurological functional recovery by promoting angiogenesis. The results of mechanistic studies revealed that ANGPTL3 is enriched in (USC-Exo) and is required for their ability to promote angiogenesis. Functional studies further confirmed that the effects of USC-Exo on angiogenesis are mediated by the PI3K/AKT signaling pathway. Conclusion: Collectively, our results indicate that USC-Exo serve as a crucial regulator of angiogenesis by delivering ANGPTL3 and may represent a promising novel therapeutic agent for SCI repair.


2021 ◽  
Vol 12 (12) ◽  
Author(s):  
Junhao Deng ◽  
Miao Li ◽  
Fanqi Meng ◽  
Zhongyang Liu ◽  
Song Wang ◽  
...  

AbstractMesenchymal stem cell (MSC) is an absorbing candidate for cell therapy in treating spinal cord injury (SCI) due to its great potential for multiple cell differentiation, mighty paracrine secretion as well as vigorous immunomodulatory effect, of which are beneficial to the improvement of functional recovery post SCI. However, the therapeutic effects of MSC on SCI have been limited because of the gradual loss of MSC stemness in the process of expanding culture. Therefore, in this study, we aimed to maintain those beneficial properties of MSC via three-dimensional spheroid cell culture and then compared them with conventionally-cultured MSCs in the treatment of SCI both in vitro and in vivo with the aid of two-photon microscope. We found that 3D human placenta-derived MSCs (3D-HPMSCs) demonstrated a significant increase in secretion of anti-inflammatory factors and trophic factors like VEGF, PDGF, FGF via QPCR and Bio-Plex assays, and showed great potentials on angiogenesis and neurite morphogenesis when co-cultured with HUVECs or DRGs in vitro. After transplantation into the injured spinal cord, 3D-HPMSCs managed to survive for the entire experiment and retained their advantageous properties in secretion, and exhibited remarkable effects on neuroprotection by minimizing the lesion cavity, inhibiting the inflammation and astrogliosis, and promoting angiogenesis. Further investigation of axonal dieback via two-photon microscope indicated that 3D-HPMSCs could effectively alleviate axonal dieback post injury. Further, mice only treated with 3D-HPMSCs obtained substantial improvement of functional recovery on electrophysiology, BMS score, and Catwalk analysis. RNA sequencing suggested that the 3D-HPMSCs structure organization-related gene was significantly changed, which was likely to potentiate the angiogenesis and inflammation regulation after SCI. These results suggest that 3D-HPMSCs may hold great potential for the treatment of SCI.


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