miR-124 and miR-128 differential expression in bone marrow stromal cells and spinal cord-derived neural stem cells

BACKGROUND: MicroRNA (miRNA) expression in stem cells provides important clues for the molecular mechanisms of stem cell proliferation and differentiation. Bone marrow stromal cells and spinal cord-derived neural stem cells exhibit potential for neural regeneration. However, miRNA expression in these cells has been rarely reported. OBJECTIVE: To explore differential expression of two nervous system-specific miRNAs, miR-124 and miR-128, in bone marrow stromal cells and spinal cord-derived neural stem cells. DESIGN, TIME AND SETTING: An In vitro, cell biology experiment was performed at the Department of Biotechnology, Shanxi Medical University from June 2008 to June 2009. MATERIALS: TaqMan miRNA assays were purchased from Applied Biosystems. METHODS: Rat bone marrow stromal cells were isolated and cultured using the whole-bone marrow method, and rat spinal cord-derived neural stem cells were obtained through neurosphere formation. TaqMan miRNA assays were used to measure miR-124 and miR-128 expression in bone marrow stromal cells and spinal cord-derived neural stem cells. MAIN OUTCOME MEASURES: Morphology of bone marrow stromal cells and spinal cord-derived neural stem cells were observed by inverted microscopy. Expression of the neural stem cell-specific marker, nestin, the bone marrow stromal cell surface marker, CD71, and expression of miR-124 and miR-128, were detected by real-time polymerase chain reaction. RESULTS: Cultured bone marrow stromal cells displayed a short fusiform shape. Flow cytometry revealed a large number of CD71-positive cells (> 95%). Cultured spinal cord-derived neural stem cells formed nestin-positive neurospheres, and quantitative detection of miRNA demonstrated that less miR-124 and miR-128 was expressed in bone marrow stromal cells compared to spinal cord-derived neural stem cells (P < 0.05). CONCLUSION: Bone marrow stromal cells and spinal cord-derived neural stem cells exhibited differential expression of miR-124 and miR-128, which suggested different characteristics in miRNA expression.

Transplantation of fibrin-thrombin encapsulated human induced neural stem cells promotes functional recovery of spinal cord injury rats through modulation of the microenvironment

Recent studies have mostly focused on engraftment of cells at the lesioned spinal cord,with the expectation that differentiated neurons facilitate recovery.Only a few studies have attempted to use transplanted cells and/or biomaterials as major modulators of the spinal cord injury microenvironment.Here,we aimed to investigate the role of microenvironment modulation by cell graft on functional recovery after spinal cord injury.Induced neural stem cells reprogrammed from human peripheral blood mononuclear cells,and/or thrombin plus fibrinogen,were transplanted into the lesion site of an immunosuppressed rat spinal cord injury model.Basso,Beattie and Bresnahan score,electrophysiological function,and immunofluorescence/histological analyses showed that transplantation facilitates motor and electrophysiological function,reduces lesion volume,and promotes axonal neurofilament expression at the lesion core.Examination of the graft and niche components revealed that although the graft only survived for a relatively short period(up to 15 days),it still had a crucial impact on the microenvironment.Altogether,induced neural stem cells and human fibrin reduced the number of infiltrated immune cells,biased microglia towards a regenerative M2 phenotype,and changed the cytokine expression profile at the lesion site.Graft-induced changes of the microenvironment during the acute and subacute stages might have disrupted the inflammatory cascade chain reactions,which may have exerted a long-term impact on the functional recovery of spinal cord injury rats.

Oscillating field stimulation promotes neurogenesis of neural stem cells through miR-124/Tal1 axis to repair spinal cord injury in rats

Spinal cord injury often leads to severe motor and sensory deficits,and prognosis using the currently available therapies remains poor.Therefore,we aimed to explore a novel therapeutic approach for improving the prognosis of spinal cord injury.In this study,we implanted oscillating field stimulation devices and transplanted neural stem cells into the thoracic region(T9–T10)of rats with a spinal cord contusion.Basso-Beattie-Bresnahan scoring revealed that oscillating field stimulation combined with neural stem cells transplantation promoted motor function recovery following spinal cord injury.In addition,we investigated the regulation of oscillating field stimulation on the miR-124/Tal1 axis in neural stem cells.Transfection of lentivirus was performed to investigate the role of Tal1 in neurogenesis of neural stem cells induced by oscillating field stimulation.Quantitative reverse transcription-polymerase chain reaction,immunofluorescence and western blotting showed that oscillating field stimulation promoted neurogenesis of neural stem cells in vitro and in vivo.Hematoxylin and eosin staining showed that oscillating field stimulation combined with neural stem cells transplantation alleviated cavities formation after spinal cord injury.Taking the results together,we concluded that oscillating field stimulation decreased miR-124 expression and increased Tal1 content,thereby promoting the neurogenesis of neural stem cells.The combination of oscillating field stimulation and neural stem cells transplantation improved neurogenesis,and thereby promoted structural and functional recovery after spinal cord injury.

New insights into the biological roles of immune cells in neural stem cells in post-traumatic injury of the central nervous system

Traumatic injuries in the central nervous system,such as traumatic brain injury and spinal cord injury,are associated with tissue inflammation and the infiltration of immune cells,which simultaneously affect the self-renewal and differentiation of neural stem cells.Howeve r,the tissue repair process instigated by endogenous neural stem cells is incapable of restoring central nervous system injuries without external intervention.Recently,resident/peripheral immune cells have been demonstrated to exert significant effects on neural stem cells.Thus,the resto ration of traumatic injuries in the central nervous system by the immune intervention in neural stem cells represents a potential therapeutic method.In this review,we discuss the roles and possible mechanisms of immune cells on the selfrenewal and differentiation of neural stem cells along with the prognosis of central nervous system injuries based on immune intervention.Finally,we discuss remaining research challenges that need to be considered in the future.Further elucidation of these challenges will fa cilitate the successful application of neural stem cells in central nervous system injuries.

Three-dimensional bioprinting collagen/silk fibroin scaffold combined with neural stem cells promotes nerve regeneration after spinal cord injury

Many studies have shown that bio-scaffolds have important value for promoting axonal regeneration of injured spinal cord.Indeed,cell transplantation and bio-scaffold implantation are considered to be effective methods for neural regeneration.This study was designed to fabricate a type of three-dimensional collagen/silk fibroin scaffold (3D-CF) with cavities that simulate the anatomy of normal spinal cord.This scaffold allows cell growth in vitro and in vivo.To observe the effects of combined transplantation of neural stem cells (NSCs) and 3D-CF on the repair of spinal cord injury.Forty Sprague-Dawley rats were divided into four groups: sham (only laminectomy was performed),spinal cord injury (transection injury of T10 spinal cord without any transplantation),3D-CF (3D scaffold was transplanted into the local injured cavity),and 3D-CF + NSCs (3D scaffold co-cultured with NSCs was transplanted into the local injured cavity.Neuroelectrophysiology,imaging,hematoxylin-eosin staining,argentaffin staining,immunofluorescence staining,and western blot assay were performed.Apart from the sham group,neurological scores were significantly higher in the 3D-CF + NSCs group compared with other groups.Moreover,latency of the 3D-CF + NSCs group was significantly reduced,while the amplitude was significantly increased in motor evoked potential tests.The results of magnetic resonance imaging and diffusion tensor imaging showed that both spinal cord continuity and the filling of injury cavity were the best in the 3D-CF + NSCs group.Moreover,regenerative axons were abundant and glial scarring was reduced in the 3D-CF + NSCs group compared with other groups.These results confirm that implantation of 3D-CF combined with NSCs can promote the repair of injured spinal cord.This study was approved by the Institutional Animal Care and Use Committee of People’s Armed Police Force Medical Center in 2017 (approval No.2017-0007.2).

Effect of spinal cord extracts after spinal cord injury on proliferation of rat embryonic neural stem cells and Notch signal pathway in vitro

Objective:To investigate the effect of the spinal cord extracts(SCE)after spinal cord injuries(SCIs)on the proliferation of rat embryonic neural stem cells(NSCs)and the expressions of mRNA of Notch1 as well as of Hes1 in this process in vitro.Methods:The experiment was conducted in 4 different mediums:NSCs+PBS(Group A-blank control group),NSCs+SCE with healthy SD rats(Croup B-normal control group),NSCs+SCE with SD rats receiving sham-operation treatment(Croup C-sham-operation group)and NSCs+SCE with SCIs rats(Group D-paraplegic group).Proliferative abilities of 4 different groups were analyzed by MTT chromatometry after co-culture for 1,2,3,4 and 5 d,respectively.The expressions of Notch 1 and Hes1 mRNA were also detected with RT-PCR after co-culture for 24 and 48 h,respectively.Results:After co-culture for 1,2,3,4 and 5 d respectively,the MTT values of group D were significantly higher than those of group A,group B and group C(P<0.05).However,there were no significantly differences regarding MTT values between group A,group B and group C after co-culture for 1,2,3,4 and 5 d,respectively(P>0.05).Both the expressions of Notch1 and Hes1 mRNA of group D were significantly higher than those of other 3 groups after co-culture for 24 h and 48 h as well(P<0.05).But there was no difference oin expressions of Notch1 and Hes1 mRNA among group A,group B and group C after co-culture for 24 h and 48 h(P>0.05).There was no difference in expressions of Notch1and Hes1 mRNA between 24 h and 48 h treatment in group D.Conclusions:SCE could promote the proliferation of NSCs.It is demonstrated that the microenvironment of SCI may promote the proliferation of NSCs.Besides,SCE could increase the expression of Notch1 and Hes1 mRNA of NSC.It can be concluded that the Notch signaling pathway activation is one of the mechanisms that locally injured microenvironment contributes to the proliferation of ENSC after SCIs.This process may be performed by up-regulating the expressions of Notch1 and Hes1 gene.

A multi-channel collagen scaffold loaded with neural stem cells for the repair of spinal cord injury

Collagen scaffolds possess a three-dimensional porous structure that provides sufficient space for cell growth and proliferation,the passage of nutrients and oxygen,and the discharge of metabolites.In this study,a porous collagen scaffold with axially-aligned luminal conduits was prepared.In vitro biocompatibility analysis of the collagen scaffold revealed that it enhances the activity of neural stem cells and promotes cell extension,without affecting cell differentiation.The collagen scaffold loaded with neural stem cells improved the hindlimb motor function in the rat model of T8 complete transection and promoted nerve regeneration.The collagen scaffold was completely degraded in vivo within 5 weeks of implantation,exhibiting good biodegradability.Rectal temperature,C-reactive protein expression and CD68 staining demonstrated that rats with spinal cord injury that underwent implantation of the collagen scaffold had no notable inflammatory reaction.These findings suggest that this novel collagen scaffold is a good carrier for neural stem cell transplantation,thereby enhancing spinal cord repair following injury.This study was approved by the Animal Ethics Committee of Nanjing Drum Tower Hospital(the Affiliated Hospital of Nanjing University Medical School),China(approval No.2019AE02005)on June 15,2019.

Induction of Functional Recovery by Co-transplantation of Neural Stem Cells and Schwann Cells in a Rat Spinal Cord Contusion Injury Model

Objective To study the transplantation efficacy of neural stem cells (NSCs) and Schwann cells (SC) in a rat model of spinal cord contusion injury. Methods Multipotent neural stem cells (NSCs) and Schwann cells were harvested from the spinal cords of embryonic rats at 16 days post coitus and sciatic nerves of newborn rats, respectively. The differential characteristics of NSCs in vitro induced by either serum-based culture or co-culture with SC were analyzed by immunofluorescence. NSCs and SCs were co-transplanted into adult rats having undergone spinal cord contusion at T9 level. The animals were weekly monitored using the Basso-Beattie-Bresnahan locomotor rating system to evaluate functional recovery from contusion-induced spinal cord injury. Migration and differentiation of transplanted NSCs were studied in tissue sections using immunohistochemical staining. Results Embryonic spinal cord-derived NSCs differentiated into a large number of oligodendrocytes in serum-based culture upon the withdrawal of mitogens. In cocultures with SCs, NSCs differentiated into neuron more readily. Rats with spinal cord contusion injury which had undergone transplantation of NSCs and SCs into the intraspinal cavity demonstrated a moderate improvement in motor functions. Conclusions SC may contribute to neuronal differentiation of NSCs in vitro and in vivo. Transplantation of NSCs and SCs into the affected area may be a feasible approach to promoting motor recovery in patients after spinal cord injury.

Transplantation of placenta-derived mesenchymal stem cell-induced neural stem cells to treat spinal cord injury

Because of their strong proliferative capacity and multi-potency, placenta-derived mesenchymal stem cells have gained interest as a cell source in the field of nerve damage repair. In the present study, human placenta-derived mesenchymal stem cells were induced to differentiate into neural stem cells, which were then transplanted into the spinal cord after local spinal cord injury in rats. The motor functional recovery and pathological changes in the injured spinal cord were observed for 3 successive weeks. The results showed that human placenta-derived mesenchymal stem cells can differentiate into neuron-like cells and that induced neural stem cells contribute to the restoration of injured spinal cord without causing transplant rejection. Thus, these cells promote the recovery of motor and sensory functions in a rat model of spinal cord injury. Therefore, human placenta-derived mesenchymal stem cells may be useful as seed cells during the repair of spinal cord injury.

Repair of spinal cord injury by neural stem cells modified with BDNF gene in rats

Objective To explore repair of spinal cord injury by neural stem cells (NSCs) modified with brain derived neurotrophic factor (BDNF) gene (BDNF-NSCs) in rats. Methods Neural stem cells modified with BDNF gene were transplanted into the complete transection site of spinal cord at the lumbar 4 (L4) level in rats. Motor function of rats' hind limbs was observed and HE and X-gal immunocytochemical staining, in situ hybridization, and retrograde HRP tracing were also performed, Results BDNF-NSCs survived and integrated well with host spinal cord. In the transplant group, some X-gal positive, NF-200 positive, GFAP positive, BDNF positive, and BDNF mRNA positive cells, and many NF-200 positive nerve fibers were observed in the injury site. Retrograde HRP tracing through sciatic nerve showed some HRP positive cells and nerve fibers near the rostral side of the injury one month after transplant and with time, they increased in number. Examinations on rats' motor function and behavior demonstrated that motor function of rats' hind limbs improved better in the transplant group than the injury group. Conclusion BDNF-NSCs can survive, differentiate, and partially integrate with host spinal cord, and they significantly ameliorate rats' motor function of hind limbs, indicating their promising role in repairing spinal cord injury.

Survival of transplanted neurotrophin-3 expressing human neural stem cells and motor function in a rat model of spinal cord injury

<正>BACKGROUND:Many methods have been attempted to repair nerves following spinal cord injury, including peripheral nerve transplantation,Schwann cell transplantation,olfactory ensheathing cell transplantation,and embryonic neural tissue transplantation.However,there is a need for improved outcomes. OBJECTIVE:To investigate the repair feasibility for rat spinal cord injury using human neural stem cells(hNSCs) genetically modified by lentivirus to express neurotrophin-3. DESIGN,TIME AND SETTING:In vitro cell biological experiment and in vivo randomized,controlled, genetic engineering experiment were performed at the Third Military Medical University of Chinese PLA and First People's Hospital of Yibin,China from March 2006 to December 2007. MATERIALS:A total of 64 adult,female,Wistar rats were used for the in vivo study.Of them,48 rats were used to establish models of spinal cord hemisection,and were subsequently equally and randomly assigned to model,genetically modified hNSC,and normal hNSC groups.The remaining 16 rats served as normal controls. METHODS:hNSCs were in vitro genetically modified by lentivirus to secrete both green fluorescence protein and neurotrophin-3.Neurotrophin-3 expression was measured by Western blot. Genetically modified hNSC or normal hNSC suspension(5×10~5) was injected into the rat spinal cord following T_(10) spinal cord hemisection.A total of 5μL Dulbecco's-modified Eagle's medium was infused into the rat spinal cord in the model group.Transgene expression and survival of transplanted hNSCs were determined by immunohistochemistry.Motor function was evaluated using the Basso,Beattie,and Bresnahan(BBB) scale. MAIN OUTCOME MEASURES:The following parameters were measured:expression of neurotrophin-3 produced by genetically modified hNSCs,transgene expression and survival of hNSCs in rats,motor function in rats. RESULTS:hNSCs were successfully genetically modified by lentivirus to stably express neurotrophin-3.The transplanted hNSCs primarily gathered at,or around,the injection site two weeks following transplantation,and gradually migrated towards the surrounding tissue. Transplanted hNSCs were observed 7.0-8.0 mm away from the injection site.In addition,hNSCs were observed 10 weeks after transplantation.At week 4,BBB locomotor scores were significantly greater in the genetically modified hNSC and normal hNSC groups,compared with the model group (P<0.05),and scores were significantly greater in the genetically modified hNSC group compared with the normal hNSC group(P<0.05). CONCLUSION:hNSCs were genetically modified with lentivirus to stably secrete neurotrophin-3. hNSCs improved motor function recovery in rats following spinal cord injury.

Mild hypothermia combined with a scaffold of Ng Rsilenced neural stem cells/Schwann cells to treat spinal cord injury

Because the inhibition of Nogo proteins can promote neurite growth and nerve cell differentiation, a cell-scaffold complex seeded with Nogo receptor(Ng R)-silenced neural stem cells and Schwann cells may be able to improve the microenvironment for spinal cord injury repair. Previous studies have found that mild hypothermia helps to attenuate secondary damage in the spinal cord and exerts a neuroprotective effect. Here, we constructed a cell-scaffold complex consisting of a poly(D,L-lactide-co-glycolic acid)(PLGA) scaffold seeded with Ng R-silenced neural stem cells and Schwann cells, and determined the effects of mild hypothermia combined with the cell-scaffold complexes on the spinal cord hemi-transection injury in the T9 segment in rats. Compared with the PLGA group and the Ng R-silencing cells + PLGA group, hindlimb motor function and nerve electrophysiological function were clearly improved, pathological changes in the injured spinal cord were attenuated, and the number of surviving cells and nerve fibers were increased in the group treated with the Ng R-silenced cell scaffold + mild hypothermia at 34°C for 6 hours. Furthermore, fewer pathological changes to the injured spinal cord and more surviving cells and nerve fibers were found after mild hypothermia therapy than in injuries not treated with mild hypothermia. These experimental results indicate that mild hypothermia combined with Ng R gene-silenced cells in a PLGA scaffold may be an effective therapy for treating spinal cord injury.

Transplantation of erythropoietin gene-modified neural stem cells improves the repair of injured spinal cord

The protective effects of erythropoietin on spinal cord injury have not been well described. Here, the eukaryotic expression plasmid pc DNA3.1 human erythropoietin was transfected into rat neural stem cells cultured in vitro. A rat model of spinal cord injury was established using a free falling object. In the human erythropoietin-neural stem cells group, transfected neural stem cells were injected into the rat subarachnoid cavity, while the neural stem cells group was injected with non-transfected neural stem cells. Dulbecco's modified Eagle's medium/F12 medium was injected into the rats in the spinal cord injury group as a control. At 1–4 weeks post injury, the motor function in the rat lower limbs was best in the human erythropoietin-neural stem cells group, followed by the neural stem cells group, and lastly the spinal cord injury group. At 72 hours, compared with the spinal cord injury group, the apoptotic index and Caspase-3 gene and protein expressions were apparently decreased, and the bcl-2 gene and protein expressions were noticeably increased, in the tissues surrounding the injured region in the human erythropoietin-neural stem cells group. At 4 weeks, the cavities were clearly smaller and the motor and somatosensory evoked potential latencies were remarkably shorter in the human erythropoietin-neural stem cells group and neural stem cells group than those in the spinal cord injury group. These differences were particularly obvious in the human erythropoietin-neural stem cells group. More CM-Dil-positive cells and horseradish peroxidase-positive nerve fibers and larger amplitude motor and somatosensory evoked potentials were found in the human erythropoietin-neural stem cells group and neural stem cells group than in the spinal cord injury group. Again, these differences were particularly obvious in the human erythropoietin-neural stem cells group. These data indicate that transplantation of erythropoietin gene-modified neural stem cells into the subarachnoid cavity to help repair spinal cord injury and promote the recovery of spinal cord function better than neural stem cell transplantation alone. These findings may lead to significant improvements in the clinical treatment of spinal cord injuries.

Repair of spinal cord injury by neural stem cells transfected with brain-derived neurotrophic factor-green fluorescent protein in rats A double effect of stem cells and growth factors?

Brain-derived neurotrophic factor (BDNF) can significantly promote nerve regeneration and repair. High expression of the BDNF-green fluorescent protein (GFP) gene persists for a long time after transfection into neural stem cells. Nevertheless, little is known about the biological characteristics of BDNF-GFP modified nerve stem cells in vivo and their ability to induce BDNF expression or repair spinal cord injury. In the present study, we transplanted BDNF-GFP transgenic neural stem cells into a hemisection model of rats. Rats with BDNF-GFP stem cells exhibited significantly increased BDNF expression and better locomotor function compared with stem cells alone. Cellular therapy with BDNF-GFP transgenic stem cells can improve outcomes better than stem cells alone and may have therapeutic potential for spinal cord injury.

E-cadherin-transfected Neural Stem Cells Transplantation for Spinal Cord Injury in Rats

The effects of E-cadherin-transfected neural stem cells(NSCs) transplantation for spinal cord injury(SCI) in rats were investigated. Sixty SD rats were randomly divided into model control group, NSCs group, empty plasmid group and E-cadherin overexpression group(n=15 each). The animal SCI model was established by using the modified Allen's method. NSCs were cultured. Rats in NSCs group were subjected to NSCs transplantation. E-cadherin gene eucaryotic expression vector and pcDNA3.1-E-cadherin were respectively transfected into cultured NSCs, serving as empty plasmid group and E-cadherin overexpression group respectively. At 7th day after transplantation, neurological function of all rats was assessed by Tarlov score. After rats were sacrificed in each group, the number of BrdU and Nestin positive cells was counted by immunohistochemistry. Immumofluorescence method was used to detect the expression of neurofilament protein(NF) and glial fibrillary acidic protein(GFAP). As compared with model control group, the Tarlov score and the number of of BrdU and Nestin positive cells, and the expression of NF and GFAP in NSCs group, empty plasmid group, and E-cadherin overexpression group were increased significantly(P<0.05), and those in the E-cadherin overexpression group were increased more significantly than the other transplantation groups(P<0.05). It was suggested that E-cadherin could be conductive to nerve regeneration and repair probably by promoting the proliferation and differentiation of NSCs.

Transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury:A Web of Science-based literature analysis

OBJECTIVE: To identify global research trends in transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury. DATA RETRIEVAL: We performed a bibliometric analysis of studies on transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury published from 2002 to 2011 and retrieved from the Web of Science, using the key words spinal cord injury along with either neural stem cell, Schwann cell or olfactory ensheathing cell. SELECTION CRITERIA: Inclusion criteria: (a) peer-reviewed published articles on neural stem cells, Schwann cells or olfactory ensheathing cells for spinal cord injury indexed in the Web of Science; (b) original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial materials and news items; and (c) published between 2002 and 2011. Exclusion criteria: (a) articles that required manual searching or telephone access; (b) documents that were not published in the public domain; and (c) corrected papers. MAIN OUTCOME MEASURES: (1) Annual publication output, distribution by journal, distribution by institution and top-cited articles on neural stem cells; (2) annual publication output, distribution by journal, distribution by institution and top-cited articles on Schwann cells; (3) annual publication output, distribution by journal, distribution by institution and top-cited articles on olfactory ensheathing cells. RESULTS: This analysis, based on articles indexed in the Web of Science, identified several research trends among studies published over the past 10 years in transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury. The number of publications increased over the 10-year period examined. Most papers appeared in journals with a focus on neurology, such as Journal of Neurotrauma, Experimental Neurology and Glia. Research institutes publishing on the use of neural stem cells to repair spinal cord injury were mostly in the USA and Canada. Those publishing on the use of Schwann cells were mostly in the USA and Canada as well. Those publishing on the use of olfactory ensheathing cells were mostly in the UK, the USA and Canada. CONCLUSION: On the basis of the large number of studies around the world, cell transplantation has proven to be the most promising therapeutic approach for spinal cord injury.

Reducing host aldose reductase activity promotes neuronal differentiation of transplanted neural stem cells at spinal cord injury sites and facilitates locomotion recovery

Neural stem cell(NSC)transplantation is a promising strategy for replacing lost neurons following spinal cord injury.However,the survival and differentiation of transplanted NSCs is limited,possibly owing to the neurotoxic inflammatory microenvironment.Because of the important role of glucose metabolism in M1/M2 polarization of microglia/macrophages,we hypothesized that altering the phenotype of microglia/macrophages by regulating the activity of aldose reductase(AR),a key enzyme in the polyol pathway of glucose metabolism,would provide a more beneficial microenvironment for NSC survival and differentiation.Here,we reveal that inhibition of host AR promoted the polarization of microglia/macrophages toward the M2 phenotype in lesioned spinal cord injuries.M2 macrophages promoted the differentiation of NSCs into neurons in vitro.Transplantation of NSCs into injured spinal cords either deficient in AR or treated with the AR inhibitor sorbinil promoted the survival and neuronal differentiation of NSCs at the injured spinal cord site and contributed to locomotor functional recovery.Our findings suggest that inhibition of host AR activity is beneficial in enhancing the survival and neuronal differentiation of transplanted NSCs and shows potential as a treatment of spinal cord injury.

Superparamagnetic Iron Oxide Labeling of Spinal Cord Neural Stem Cells Genetically Modified by Nerve Growth Factor-β

This study established superparamagnetic iron oxide (SPIO)-labeled nerve growth factor-β (NGF-β) gene-modified spinal cord-derived neural stem cells (NSCs). The E14 rat embryonic spinal cord-derived NSCs were isolated and cultured. The cells of the third passage were transfected with plasmid pcDNA3-hNGFβ by using FuGENE HD transfection reagent. The expression of NGF-β was measured by immunocytochemistry and Western blotting. The positive clones were selected, allowed to proliferate and then labeled with SPIO, which was mediated by FuGENE HD transfection reagent. Prussian blue staining and transmission electron microscopy (TEM) were used to identify the SPIO particles in the cells. The distinctive markers for stem cells (nestin), neuron (β-Ⅲ-tubulin), oli-godendrocyte (CNPase) and astrocyte (GFAP) were employed to evaluate the differentiation ability of the labeled cells. The immunocytochemistry and western blotting showed that NGF-β was expressed in spinal cordderived NSCs. Prussian blue staining indicated that numerous blue-stained particles appeared in the cytoplasma of the labeled cells. TEM showed that SPIO particles were found in vacuolar structures of different sizes and the cytoplasma. The immunocytochemistry demonstrated that the labeled cells were nestin-positive. After differentiation, the cells expressed β-III-tubulin, CNPase and GFAP. It was concluded that the SPIO-labeled NGF-β gene-modified spinal cord-derived NSC were successfully established, which are multipotent and capable of self-renewal.

Improvement of neurological function in rats with spinal cord injury after the transplantation of neural stem cells directly differentiated from bone marrow mesenchymal stem cells

Objective To study the effect and mechanism of neurological function recovery in rats with spinal cord injury ( SCI) rats after transplantation of neural stem cells which are directly differentiated from bone marrow mesenchymal stem cells ( BMSC ) ,and to investigate the suitable engraftment time. Methods BMSC at 3rd passage were differentiated into neural stem cells ( NSC) , and immunofluorescence staining was used to

Autophagy regulation combined with stem cell therapy for treatment of spinal cord injury

Stem cells are a group of cells with unique self-renewal and differentiation abilities that have great prospects in the repair of spinal cord injury. However, stem cell renewal and differentiation require strict control of protein turnover in the stem cells to achieve cell remodeling. As a highly conserved “gatekeeper” of cell homeostasis, autophagy can regulate cell remodeling by precisely controlling protein turnover in cells. Recently, it has been found that the expression of autophagy markers changes in animal models of spinal cord injury. Therefore, understanding whether autophagy can affect the fate of stem cells and promote the repair of spinal cord injury is of considerable clinical value. This review expounds the importance of autophagy homeostasis control for the repair of spinal cord injury from three aspects—pathophysiology of spinal cord injury, autophagy and stem cell function, and autophagy and stem cell function in spinal cord injury—and proposes the synergistic therapeutic effect of autophagy and stem cells in spinal cord injury.