Runx2 is a major regulator of osteoblast differentiation and function;however,the role of Runx2 in peripheral nerve repair is unclea r.Here,we analyzed Runx2expression following injury and found that it was specifical...Runx2 is a major regulator of osteoblast differentiation and function;however,the role of Runx2 in peripheral nerve repair is unclea r.Here,we analyzed Runx2expression following injury and found that it was specifically up-regulated in Schwann cells.Furthermore,using Schwann cell-specific Runx2 knocko ut mice,we studied peripheral nerve development and regeneration and found that multiple steps in the regeneration process following sciatic nerve injury were Runx2-dependent.Changes observed in Runx2 knoc kout mice include increased prolife ration of Schwann cells,impaired Schwann cell migration and axonal regrowth,reduced re-myelination of axo ns,and a block in macrophage clearance in the late stage of regeneration.Taken together,our findings indicate that Runx2 is a key regulator of Schwann cell plasticity,and therefore peripheral nerve repair.Thus,our study shows that Runx2 plays a major role in Schwann cell migration,re-myelination,and peripheral nerve functional recovery following injury.展开更多
Schwann cells in peripheral nerves react to traumatic nerve injury by attempting to grow and regenerate.Howeve r,it is unclear what factors play a role in this process.In this study,we searched a GEO database and foun...Schwann cells in peripheral nerves react to traumatic nerve injury by attempting to grow and regenerate.Howeve r,it is unclear what factors play a role in this process.In this study,we searched a GEO database and found that expression of platelet factor 4 was markedly up-regulated after sciatic nerve injury.Platelet factor is an important molecule in cell apoptosis,diffe rentiation,survival,and proliferation.Further,polymerase chain reaction and immunohistochemical staining confirmed the change in platelet factor 4 in the sciatic nerve at different time points after injury.Enzyme-linked immunosorbent assay confirmed that platelet factor 4 was secreted by Schwann cells.We also found that silencing platelet factor 4 decreased the proliferation and migration of primary cultured Schwann cells,while exogenously applied platelet factor 4 stimulated Schwann cell prolife ration and migration and neuronal axon growth.Furthermore,knocking out platelet factor 4 inhibited the prolife ration of Schwann cells in injured rat sciatic nerve.These findings suggest that Schwann cell-secreted platelet factor 4 may facilitate peripheral nerve repair and regeneration by regulating Schwann cell activation and axon growth.Thus,platelet factor 4 may be a potential therapeutic target for traumatic peripheral nerve injury.展开更多
Exosomes exhibit complex biological functions and mediate a variety of biological processes,such as promoting axonal regeneration and functional recove ry after injury.Long non-coding RNAs(IncRNAs)have been reported t...Exosomes exhibit complex biological functions and mediate a variety of biological processes,such as promoting axonal regeneration and functional recove ry after injury.Long non-coding RNAs(IncRNAs)have been reported to play a crucial role in axonal regeneration.Howeve r,the role of the IncRNA-microRNAmessenger RNA(mRNA)-competitive endogenous RNA(ceRNA)network in exosome-mediated axonal regeneration remains unclear.In this study,we performed RNA transcriptome sequencing analysis to assess mRNA expression patterns in exosomes produced by cultured fibroblasts(FC-EXOs)and Schwann cells(SCEXOs).Diffe rential gene expression analysis,Gene Ontology analysis,Kyoto Encyclopedia of Genes and Genomes analysis,and protein-protein intera ction network analysis were used to explo re the functions and related pathways of RNAs isolated from FC-EXOs and SC-EXOs.We found that the ribosome-related central gene Rps5 was enriched in FC-EXOs and SC-EXOs,which suggests that it may promote axonal regeneration.In addition,using the miRWalk and Starbase prediction databases,we constructed a regulatory network of ceRNAs targeting Rps5,including 27 microRNAs and five IncRNAs.The ceRNA regulatory network,which included Ftx and Miat,revealed that exsosome-derived Rps5 inhibits scar formation and promotes axonal regeneration and functional recovery after nerve injury.Our findings suggest that exosomes derived from fibro blast and Schwann cells could be used to treat injuries of peripheral nervous system.展开更多
Background:During Enterovirus type 71(EV71)infection,the structural viral protein 1(VP1)activates endoplasmic reticulum(ER)stress associated with peripheral myelin protein 22(PMP22)accumulation and induces autophagy.H...Background:During Enterovirus type 71(EV71)infection,the structural viral protein 1(VP1)activates endoplasmic reticulum(ER)stress associated with peripheral myelin protein 22(PMP22)accumulation and induces autophagy.However,the specific mechanism behind this process remains elusive.Methods:In this research,we used the VP1-overexpressing mouse Schwann cells(SCs)models co-transfected with a PMP22 silencing or Autocrine motility factor receptor(AMFR/gp78)overexpressing vector to explore the regulation of gp78 on PMP22 and its relationship with autophagy and apoptosis.Results:The activity of gp78 could be influenced by EV71-VP1,leading to a decrease in the ubiquitination and degradation of PMP22,resulting in PMP22 accumulation in ER.In VP1-overexpressing mouse SCs,all three ER stress sensors,including pancreatic endoplasmic reticulum kinase(PERK),activating transcription factor 6(ATF6)and inositol-requiring enzyme 1(IRE1)and the related downstream signals(C/EBP-homologous protein(CHOP)and Caspase 12)were activated,as well as the ER-resident chaperone Glucose-regulated protein 78(GRP78).In addition,VP1 upregulated the autophagy marker Microtubule-associated protein 1 light chain 3 beta(LC3B),while PMP22 silencing or gp78 overexpression reversed the phenomenon.Meanwhile,PMP22 silencing or gp78 overexpression increased proliferation of EV71-VP1-transfected mouse SCs.Conclusion:Gp78 could regulate PMP22 accumulation through ubiquitination degradation and cause ER stress and autophagy in EV71-VP1-overexpressing mouse SCs.Therefore,the gp78/PMP22/ER stress axis might emerge as a promising therapeutic target for myelin and neuronal damage induced by EV71 infection.展开更多
Research has shown that long-chain noncoding RNAs(lncRNAs) are involved in the regulation of a variety of biological processes, including peripheral nerve regeneration, in part by acting as competing endogenous RNAs. ...Research has shown that long-chain noncoding RNAs(lncRNAs) are involved in the regulation of a variety of biological processes, including peripheral nerve regeneration, in part by acting as competing endogenous RNAs. c-Jun plays a key role in the repair of peripheral nerve injury. However, the precise underlying mechanism of c-Jun remains unclear. In this study, we performed microarray and bioinformatics analysis of mouse crush-injured sciatic nerves and found that the lncRNA Pvt1 was overexpressed in Schwann cells after peripheral nerve injury. Mechanistic studies revealed that Pvt1 increased c-Jun expression through sponging miRNA-214. We overexpressed Pvt1 in Schwann cells cultured in vitro and found that the proliferation and migration of Schwann cells were enhanced, and overexpression of miRNA-214 counteracted the effects of Pvt1 overexpression on Schwann cell proliferation and migration. We conducted in vivo analyses and injected Schwann cells overexpressing Pvt1 into injured sciatic nerves of mice. Schwann cells overexpressing Pvt1 enhanced the regeneration of injured sciatic nerves following peripheral nerve injury and the locomotor function of mice was improved. Our findings reveal the role of lncRNAs in the repair of peripheral nerve injury and highlight lncRNA Pvt1 as a novel potential treatment target for peripheral nerve injury.展开更多
Circular RNAs(circRNAs)play a vital role in diabetic peripheral neuropathy.However,their expression and function in Schwann cells in individuals with diabetic peripheral neuropathy remain poorly understood.Here,we per...Circular RNAs(circRNAs)play a vital role in diabetic peripheral neuropathy.However,their expression and function in Schwann cells in individuals with diabetic peripheral neuropathy remain poorly understood.Here,we performed protein profiling and circRNA sequencing of sural nerves in patients with diabetic peripheral neuropathy and controls.Protein profiling revealed 265 differentially expressed proteins in the diabetic peripheral neuropathy group.Gene Ontology indicated that differentially expressed proteins were mainly enriched in myelination and mitochondrial oxidative phosphorylation.A real-time polymerase chain reaction assay performed to validate the circRNA sequencing results yielded 11 differentially expressed circRNAs.circ_0002538 was markedly downregulated in patients with diabetic peripheral neuropathy.Further in vitro experiments showed that overexpression of circ_0002538 promoted the migration of Schwann cells by upregulating plasmolipin(PLLP)expression.Moreover,overexpression of circ_0002538 in the sciatic nerve in a streptozotocin-induced mouse model of diabetic peripheral neuropathy alleviated demyelination and improved sciatic nerve function.The results of a mechanistic experiment showed that circ_0002538 promotes PLLP expression by sponging miR-138-5p,while a lack of circ_0002538 led to a PLLP deficiency that further suppressed Schwann cell migration.These findings suggest that the circ_0002538/miR-138-5p/PLLP axis can promote the migration of Schwann cells in diabetic peripheral neuropathy patients,improving myelin sheath structure and nerve function.Thus,this axis is a potential target for therapeutic treatment of diabetic peripheral neuropathy.展开更多
Studies have shown that human hair keratin(HHK) has no antigenicity and excellent mechanical properties. Schwann cells, as unique glial cells in the peripheral nervous system, can be induced by interleukin-1β to secr...Studies have shown that human hair keratin(HHK) has no antigenicity and excellent mechanical properties. Schwann cells, as unique glial cells in the peripheral nervous system, can be induced by interleukin-1β to secrete nerve growth factor, which promotes neural regeneration. Therefore, HHK with Schwann cells may be a more effective approach to repair nerve defects than HHK without Schwann cells. In this study, we established an artificial nerve graft by loading an HHK skeleton with activated Schwann cells. We found that the longitudinal HHK microfilament structure provided adhesion medium, space and direction for Schwann cells, and promoted Schwann cell growth and nerve fiber regeneration. In addition, interleukin-1β not only activates Schwann cells, but also strengthens their activity and increases the expression of nerve growth factors. Activated Schwann cells activate macrophages, and activated macrophages secrete interleukin-1β, which maintains the activity of Schwann cells. Thus, a beneficial cycle forms and promotes nerve repair. Furthermore, our studies have found that the newly constructed artificial nerve graft promotes the improvements in nerve conduction function and motor function in rats with sciatic nerve injury, and increases the expression of nerve injury repair factors fibroblast growth factor 2 and human transforming growth factor B receptor 2. These findings suggest that this artificial nerve graft effectively repairs peripheral nerve injury.展开更多
The functional properties of endogenous Schwann cells(SCs)during nerve repair are dynamic.Optimizing the functional properties of SCs at different stages of nerve repair may have therapeutic benefit in improving the r...The functional properties of endogenous Schwann cells(SCs)during nerve repair are dynamic.Optimizing the functional properties of SCs at different stages of nerve repair may have therapeutic benefit in improving the repair of damaged nerves.Previous studies showed that miR-221-3p promotes the proliferation and migration of SCs,and miR-338-3p promotes the myelination of SCs.In this study,we established rat models of sciatic nerve injury by bridging the transected sciatic nerve with a silicone tube.We injected a miR-221 lentiviral vector system together with a doxycycline-inducible Tet-On miR-338 lentiviral vector system into the cavity of nerve conduits of nerve stumps to sequentially regulate the biological function of endogenous SCs at different stages of nerve regeneration.We found that the biological function of SCs was sequentially regulated,the diameter and density of myelinated axons were increased,the expression levels of NF200 and myelin basic protein were increased,and the function of injured peripheral nerve was improved using this system.miRNA Target Prediction Database prediction,Nanopore whole transcriptome sequencing,quantitative PCR,and dual luciferase reporter gene assay results predicted and verified Cdkn1b and Nrp1 as target genes of miR-221-3p and miR-338-3p,respectively,and their regulatory effects on SCs were confirmed in vitro.In conclusion,here we established a new method to enhance nerve regeneration through sequential regulation of biological functions of endogenous SCs,which establishes a new concept and model for the treatment of peripheral nerve injury.The findings from this study will provide direct guiding significance for clinical treatment of sciatic nerve injury.展开更多
The trigeminal root entry zone is the zone at which the myelination switches from peripheral Schwann cells to central oligodendrocytes.Its special anatomical and physiological structure renders it susceptible to nerve...The trigeminal root entry zone is the zone at which the myelination switches from peripheral Schwann cells to central oligodendrocytes.Its special anatomical and physiological structure renders it susceptible to nerve injury.The etiology of most primary trigeminal neuralgia is closely related to microvascular compression of the trigeminal root entry zone.This study aimed to develop an efficient in vitro model mimicking the glial environment of trigeminal root entry zone as a tool to investigate the effects of glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor on the structural and functional integrity of trigeminal root entry zone and modulation of cellular interactions.Primary astrocytes and Schwann cells isolated from trigeminal root entry zone of postnatal rats were inoculated into a two-well silicon culture insert to mimic the trigeminal root entry zone microenvironment and treated with glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor.In monoculture,glial cell line-derived neurotrophic factor promoted the migration of Schwann cells,but it did not have effects on the migration of astrocytes.In the co-culture system,glial cell line-derived neurotrophic factor promoted the bidirectional migration of astrocytes and Schwann cells.Brain-derived neurotrophic factor markedly promoted the activation and migration of astrocytes.However,in the co-culture system,brain-derived neurotrophic factor inhibited the migration of astrocytes and Schwann cells to a certain degree.These findings suggest that glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor are involved in the regulation of the astrocyte-Schwann cell interaction in the co-culture system derived from the trigeminal root entry zone.This system can be used as a cell model to study the mechanism of glial dysregulation associated with trigeminal nerve injury and possible therapeutic interventions.展开更多
Schwann cells play a critical role in peripheral nerve regeneration through dedifferentiation and proliferation. In a previous study, we performed microarray analysis of the sciatic nerve after injury. Accordingly, we...Schwann cells play a critical role in peripheral nerve regeneration through dedifferentiation and proliferation. In a previous study, we performed microarray analysis of the sciatic nerve after injury. Accordingly, we predicted that long non-coding RNA NONMMUG014387 may promote Schwann cell proliferation after peripheral nerve injury, as bioinformatic analysis revealed that the target gene of NONMMUG014387 was collagen triple helix repeat containing 1(Cthrc1). Cthrc1 may promote cell proliferation in a variety of cells by activating Wnt/PCP signaling. Nonetheless, bioinformatic analysis still needs to be verified by biological experiment. In this study, the candidate long non-coding RNA, NONMMUG014387, was overexpressed in mouse Schwann cells by recombinant adenovirus transfection. Plasmid p HBAd-MCMV-GFP-NONMMUG014387 and p HBAd-MCMV-GFP were transfected into Schwann cells. Schwann cells were divided into three groups: control(Schwann cells without intervention), Ad-GFP(Schwann cells with GFP overexpression), and Ad-NONMMUGO148387(Schwann cells with GFP and NONMMUGO148387 overexpression). Cell Counting Kit-8 assay was used to evaluate proliferative capability of mouse Schwann cells after NONMMUG014387 overexpression. Polymerase chain reaction and western blot assay were performed to investigate target genes and downstream pathways of NONMMUG014387. Cell proliferation was significantly increased in Schwann cells overexpressing lnc RNA NONMMUG014387 compared with the other two groups. Further, compared with the control group, m RNA and protein levels of Cthrc1, Wnt5 a, ROR2, Rho A, Rac1, JNK, and ROCK were visibly up-regulated in the Ad-NONMMUGO148387 group. Our findings confirm that long non-coding RNA NONMMUG014387 can promote proliferation of Schwann cells surrounding the injury site through targeting Cthrc1 and activating the Wnt/PCP pathway.展开更多
Peripheral nerve injury(PNI)is common and,unlike damage to the central nervous system injured nerves can effectively regenerate depending on the location and severity of injury.Peripheral myelinating glia,Schwann cell...Peripheral nerve injury(PNI)is common and,unlike damage to the central nervous system injured nerves can effectively regenerate depending on the location and severity of injury.Peripheral myelinating glia,Schwann cells(SCs),interact with various cells in and around the injury site and are important for debris elimination,repair,and nerve regeneration.Following PNI,Wallerian degeneration of the distal stump is rapidly initiated by degeneration of damaged axons followed by morphologic changes in SCs and the recruitment of circulating macrophages.Interaction with fibroblasts from the injured nerve microenvironment also plays a role in nerve repair.The replication and migration of injury-induced dedifferentiated SCs are also important in repairing the nerve.In particular,SC migration stimulates axonal regeneration and subsequent myelination of regenerated nerve fibers.This mobility increases SC interactions with other cells in the nerve and the exogenous environment,which influence SC behavior post-injury.Following PNI,SCs directly and indirectly interact with other SCs,fibroblasts,and macrophages.In addition,the inter-and intracellular mechanisms that underlie morphological and functional changes in SCs following PNI still require further research to explain known phenomena and less understood cell-specific roles in the repair of the injured peripheral nerve.This review provides a basic assessment of SC function post-PNI,as well as a more comprehensive evaluation of the literature concerning the SC interactions with macrophages and fibroblasts that can influence SC behavior and,ultimately,repair of the injured nerve.展开更多
Schwann cell proliferation,migration and remyelination of regenerating axons contribute to regeneration after peripheral nervous system injury.Lithium promotes remyelination by Schwann cells and improves peripheral ne...Schwann cell proliferation,migration and remyelination of regenerating axons contribute to regeneration after peripheral nervous system injury.Lithium promotes remyelination by Schwann cells and improves peripheral nerve regeneration.However,whether lithium modulates other phenotypes of Schwann cells,especially their proliferation and migration remains elusive.In the current study,primary Schwann cells from rat sciatic nerve stumps were cultured and exposed to 0,5,10,15,or 30 mM lithium chloride(LiCl)for 24 hours.The effects of LiCl on Schwann cell proliferation and migration were examined using the Cell Counting Kit-8,5-ethynyl-2′-deoxyuridine,Transwell and wound healing assays.Cell Counting Kit-8 and 5-ethynyl-2′-deoxyuridine assays showed that 5,10,15,and 30 mM LiCl significantly increased the viability and proliferation rate of Schwann cells.Transwell-based migration assays and wound healing assays showed that 10,15,and 30 mM LiCl suppressed the migratory ability of Schwann cells.Furthermore,the effects of LiCl on the proliferation and migration phenotypes of Schwann cells were mostly dose-dependent.These data indicate that lithium treatment significantly promotes the proliferation and inhibits the migratory ability of Schwann cells.This conclusion will inform strategies to promote the repair and regeneration of peripheral nerves.All of the animal experiments in this study were ethically approved by the Administration Committee of Experimental Animal Center of Nantong University,China(approval No.20170320-017)on March 2,2017.展开更多
Biomaterial bridging provides physical substrates to guide axonal growth across the lesion.To achieve efficient directional guidance,combinatory strategies using permissive matrix,cells and trophic factors are necessa...Biomaterial bridging provides physical substrates to guide axonal growth across the lesion.To achieve efficient directional guidance,combinatory strategies using permissive matrix,cells and trophic factors are necessary.In the present study,we evaluated permissive effect of poly(acrylonitrile-co-vinyl chloride)guidance channels filled by different densities of laminin-precoated unidirectional polypropylene filaments combined with Schwann cells,and glial cell line-derived neurotrophic factor for axonal regeneration through a T10 hemisected spinal cord gap in adult rats.We found that channels with filaments significantly reduced the lesion cavity,astrocytic gliosis,and inflammatory responses at the graft-host boundaries.The laminin coated low density filament provided the most favorable directional guidance for axonal regeneration which was enhanced by co-grafting of Schwann cells and glial cell line-derived neurotrophic factor.These results demonstrate that the combinatorial strategy of filament-filled guiding scaffold,adhesive molecular laminin,Schwann cells,and glial cell line-derived neurotrophic factor,provides optimal topographical cues in stimulating directional axonal regeneration following spinal cord injury.This study was approved by Indiana University Institutional Animal Care and Use Committees(IACUC#:11011)on October 29,2015.展开更多
Autophagy has been shown to play an important role in Parkinson’s disease.We hypothesized that skin-derived precursor cells exhibit neuroprotective effects in Parkinson’s disease through affecting autophagy.In this ...Autophagy has been shown to play an important role in Parkinson’s disease.We hypothesized that skin-derived precursor cells exhibit neuroprotective effects in Parkinson’s disease through affecting autophagy.In this study,6-hydroxydopamine-damaged SH-SY5Y cells were pretreated with a culture medium containing skin-derived precursors differentiated into Schwann cells(SKP-SCs).The results showed that the SKP-SC culture medium remarkably enhanced the activity of SH-SY5Y cells damaged by 6-hydroxydopamine,reduced excessive autophagy,increased tyrosine hydroxylase expression,reducedα-synuclein expression,reduced the autophagosome number,and activated the PI3K/AKT/mTOR pathway.Autophagy activator rapamycin inhibited the effects of SKP-SCs,and autophagy inhibitor 3-methyladenine had the opposite effect.These findings confirm that SKP-SCs modulate the PI3K/AKT/mTOR pathway to inhibit autophagy,thereby exhibiting a neuroprotective effect in a cellular model of Parkinson’s disease.This study was approved by the Animal Ethics Committee of Laboratory Animal Center of Nantong University(approval No.S20181009-205)on October 9,2018.展开更多
Pannexin 1(Panx 1),as a large-pore membrane channel,is highly permeable to ATP and other signaling molecules.Previous studies have demonstrated the expression of Panx 1 in the nervous system,including astrocytes,micro...Pannexin 1(Panx 1),as a large-pore membrane channel,is highly permeable to ATP and other signaling molecules.Previous studies have demonstrated the expression of Panx 1 in the nervous system,including astrocytes,microglia,and neurons.However,the distribution and function of Panx 1 in the peripheral nervous system are not clear.Blocking the function of Panx 1 pharmacologically(carbenoxolone and probenecid)or with small interfering RNA targeting pannexins can greatly reduce hypotonicity-induced ATP release.Treatment of Schwann cells with a Ras homolog family member(Rho)GTPase inhibitor and small interfering RNA targeting Rho or cytoskeleton disrupting agents,such as nocodazole or cytochalasin D,revealed that hypotonicity-induced ATP release depended on intracellular RhoA and the cytoskeleton.These findings suggest that Panx 1 participates in ATP release in Schwann cells by regulating RhoA and the cytoskeleton arrangement.This study was approved by the Animal Ethics Committee of Nantong University,China(No.S20180806-002)on August 5,2018.展开更多
Peripheral nerve injury is a common neurodegenerative disease,which causes disability and a huge economic burden for patients.MicroRNAs(miRNAs)have been acknowledged as major regulators and therapeutic targets of neur...Peripheral nerve injury is a common neurodegenerative disease,which causes disability and a huge economic burden for patients.MicroRNAs(miRNAs)have been acknowledged as major regulators and therapeutic targets of neurological disease.Thus,the functional studies of miRNAs in neurological disease will contribute to discover new therapeutic targets for peripheral nerve injury.Sprague Dawley rats treated sciatic nerve surgical injury were regarded as peripheral nerve injury model in vivo.The expression of miR-494-3p and Kruppel like factor7(KLF7)were measured by Real-time quantitative polymerase chain reaction(RT-qPCR)assay.In addition,western blot analysis was conducted to measure the protein levels of KLF7,Bax,Bcl-2,and C-caspase 3.Cell viability and apoptosis were detected in Schwann cells by EdU stain and flow cytometry,respectively.The interaction between miR-494-3p and KLF7 was investigated by dual-luciferase reporter assay.The expression of miR-494-3p was reduced at the beginning,but KLF7 was enhanced in Sprague Dawley rats with peripheral nerve injury.Knockdown of miR-494-3p promoted cell proliferation and suppressed apoptosis,while overexpression of miR-494-3p or silencing KLF7 led to opposite results.Moreover,the upregulation of KLF7 attenuated miR-494-3p overexpression-induced suppressive effects on viability and promotion of apoptosis in Schwann cells.MiR-494-3p negatively regulates KLF7 in Schwann cells to mediate proliferation and apoptosis.展开更多
BACKGROUND: Animal experiments and clinical studies about tissue engineering method applied to repair nerve injury mainly focus on seeking ideal artificial nerve grafts, nerve conduit and seed cells. Autologous nerve,...BACKGROUND: Animal experiments and clinical studies about tissue engineering method applied to repair nerve injury mainly focus on seeking ideal artificial nerve grafts, nerve conduit and seed cells. Autologous nerve, allogeneic nerve and xenogeneic nerve are used to bridge nerve defects, it is one of the methods to promote the repair of nerve injury by culturing and growing Schwann cells, which can secrete various neurotrophic factor activities, in the grafts. OBJECTIVE: To observe the effect of acellular nerve grafts co-cultured with Schwann cells in repairing defects of sciatic nerve. DESIGN: An observational comparative study. SETTING: Tissue Engineering Laboratory of China Medical University. MATERIALS: The experiment was carried out in the Tissue Engineering Laboratory of China Medical University between April 2004 and April 2005. Forty neonatal Sprague-Dawley rats of 5-8 days (either males or females) and 24 male Wistar rats of 180-220 g were provided by the experimental animal center of China Medical University. METHODS: ① Culture of Schwann cells: The bilateral sciatic nerves and branchial plexus were isolated from the 40 neonatal SD rats. The sciatic nerves were enzymatically digested with collagenase and dispase, isolatd, purified and cultured with the method of speed-difference adhersion, and identified with the SABC immunohistochemical method. ② Model establishment: In vitro Schwann cells were microinjected into 10-mm long acellular nerve grafts repairing a surgically created gap in the rat sciatic nerve. According to the different grafted methods, the animals were randomly divided into three groups: autografts (n=8), acellular nerve grafts (n=8), or acellular nerve grafts with Schwann cells (n=8). ③ The regenerated nerve fiber number and average diameter of myeline sheath after culture were statistically anlayzed. MAIN OUTCOME MEASURES: ① The regenerated nerve ultrastructure, total number and density of myelinated nerve fibers, and the thickness of myeline sheath were observed under electron microscope. ② The images were processed with the Mias-1000 imaging analytical system to calculate the number of myelinated nerve fibers, and the thickness of myeline sheath. RESULTS: All the 24 Wistar rats were involved in the analysis of results. ① Results observed under transmission electron microscope: The regenerated myelinated nerve fibers in the group of acellular nerve grafts with Schwann cells were more even than those in the group of acellular nerve grafts, the number of myelinated nerve fibers and thickness of myelin sheath were close to those in the allografts group (P > 0.05), but significantly different from those in the group of acellular nerve grafts (P < 0.05). ② Results observed under scanning electron microscope: A great amount of Schwann cells with two polars were observed in the group of grafts with Schwann cells, the feature of cultured Schwann cells showed shoulder by shoulder, head to head. ③ The number of myelinated nerve fibers and thickness of myelin sheath analyzed by Mias-1000 imaging system in the group of acellular nerve grafts with Schwann cells were close to those in the autografts group (P > 0.05), but significantly different from those in the group of acellular nerve grafts (P < 0.05). CONCLUSION: Host axonal regeneration is significantly increased after implant of acellular nerve grafts. Acellular nerve grafts with Schwann cells offers a novel approach for repairing the gap of nerve defect.展开更多
OBJECTIVE The proteasome inhibitor bortezomib(BTZ)is a first-line anti-multi⁃ple myeloma drug.BTZ-induced peripheral neu⁃ropathy(BIPN)is a main adverse effect that char⁃acterized by neuropathic pain.There is still no ...OBJECTIVE The proteasome inhibitor bortezomib(BTZ)is a first-line anti-multi⁃ple myeloma drug.BTZ-induced peripheral neu⁃ropathy(BIPN)is a main adverse effect that char⁃acterized by neuropathic pain.There is still no strategy to prevent or treat BIPN,attributed to the unidentified mechanisms underlying BIPN.Previous studies suggested that BTZ impairs Schwann cells and thus leads to axonal demye⁃lination,whereas it remained not fully understood how BTZ cause Schwann cell death.It was observed that BTZ upregulates the autophagy marker LC3-Ⅱprotein in Schwann cells.However,it remains unclear whether BTZ causes autopha⁃gy-lysosome dysfunction in Schwann cells.METHODS The male C57BL/6 mice were intra⁃venous injection of BTZ(1 mg·kg-1 per day,twice weekly for a total of 4 weeks).The paw withdraw⁃al latency was tested by the Von Frey test and Hargreaves test to reflect the neuropathic pain.The conduction velocity and the action potential amplitude of the tail nerve were tested by neuro⁃physiological assessment to reflect peripheral nerve function.The histomorphology of the sciat⁃ic nerves was detected by immunofluorescence and transmission electron microscopy to reflect the demyelination and axonal degeneration.The RSC96 cells,the Schwann cell-like immortal cells,were cultured and exposed to BTZ.The lysosomal function was determined by Lyso⁃Tracker and DQ-BSA staining.Autophagy-relat⁃ed proteins,including p62 and LC3,and lysosom⁃al hydrolase cathepsin B were determined by Western blotting.RESULTS①BTZ induced mechano-allodynia,neurological conduction abnormalities of the tail nerve,demyelination and axonal degeneration of the sciatic nerves.②BTZ caused lysosomal dysfunction,resulting in the blockade of autophagy flux in Schwann cells and sciatic nerves.③The lysosomal activator Torin1 reversed lysosomal dysfunction caused by BTZ in Schwann cells.④Torin1 improved BTZ-induced mechano-allodynia and demyelination of sciatic nerves.CONCLUSION BTZ led to lyso⁃somal dysfunction in Schwann cells and contrib⁃uted to BIPN.Lysosomal activation could be a promising strategy for BIPN intervention.展开更多
Schwann cells play an important role in the peripheral nervous system, especially in nerve repair following injury, so artificial nerve regeneration requires an effective technique for obtaining purified Schwann cells...Schwann cells play an important role in the peripheral nervous system, especially in nerve repair following injury, so artificial nerve regeneration requires an effective technique for obtaining purified Schwann cells. In vivo and in vitro pre-degeneration of peripheral nerves have been shown to obtain high-purity Schwann cells. We believed that in vitro pre-degeneration was simple and controllable, and available for the clinic. Thus, we co-cultured the crushed sciatic nerves with bone marrow-derived cells in vitro. Results demonstrated that, 3 hours after injury, a large number of mononuclear cells moved to the crushed nerves and a large number of bone marrow-derived cells infiltrated the nerve segments. These changes promoted the degradation of the nerve segments, and the dedifferentiation and proliferation of Schwann cells. Neural cell adhesion molecule and glial fibrillary acidic protein expression were detected in the crushed nerves. Schwann cell yield was 9.08 ± 2.01 × 104/mg. The purity of primary cultured Schwann cells was 88.4 ± 5.79%. These indicate a successful new method for obtaining Schwann cells of high purity and yield from adult crushed sciatic nerve using bone marrow-derived cells.展开更多
BACKGROUND: Schwann cells (SCs) are neuroglial cells of peripheral nerve and play a key role in repairing peripheral nerve injury; therefore, it provides an important evidence for transplantation of SCs which are char...BACKGROUND: Schwann cells (SCs) are neuroglial cells of peripheral nerve and play a key role in repairing peripheral nerve injury; therefore, it provides an important evidence for transplantation of SCs which are characterized by active proliferation and adult high-purity in vitro after nerve injury in clinic, and also develops a new therapeutic way for nerve injury. OBJECTIVE: To investigate an effective technique for isolating adult activated Schwann cells. DESIGN: Controlled observational study. SETTING: Mudanjiang Medical College. MATERIALS: The experiment was completed at the Department of Medical Genetics of Harbin Medical University from March 2003 to April 2005. Health female Wistar rats, aged 2 months, weighting 150-160 g, were randomly divided into 3 groups with 5 in each group. METHODS: The right sciatic nerves from 15 Wistar rats were exposed and transected at the mid thigh under pentobarbital anesthesia (4 mg/kg, i.p). Seven days later, the distal segments of the predegenerated nerves were removed and used to produce adult Schwann cell cultures. The distal segment of the predegenerated nerve, 20 mm in length, was resected. The nerve was cut into pieces 1 mm in length and incubated for 3 hours under CO2 at 37 ℃ with an enzyme mixture of 0.05% collagenase/dispase. Rats were divided into 3 groups: ① Group 1: The nerve fragments were explanted in poly-L-lysine and laminin-coated dishes with BS medium from the 1st to the 6th day. On the 6th day, the fragments were removed into a new poly-L-lysine-laminin-coated dish and the BS medium was changed to BS with 10% FBS. The nerve fragments were replaced repeatedly in the same way in new dishes on the 12th and the 18th days. ② Group 2: For the first 3 days, the nerve fragments were fed with BS with 10% FBS. This medium was changed to BS medium on the third day. The nerve fragments were removed to another dish on day 6 and BS medium was changed to BS with 25 mL/L FBS. Hereafter the culture method was the same as for group 1. ③ Group 3: For the first 6 days, nerve fragments were incubated in a dish not coated with poly-L-lysine and laminin, in BS medium supplemented with 8×107 U/L of penicillin-streptomycin. On the 6th day, the nerve fragments were removed to a poly-L-lysine-laminin-coated dish and cultured in BS with 25 mL/L FBS. On the 12th day, the nerve fragments were explanted a second dish and fed with BS containing 100 mL/L FBS. On the 18th day, they were explanted to a third poly-L-lysine-laminin-coated dish. SCs were obtained from all 3 dishes on the 21st day. Finally, purity and density of SCs were identified and proliferation index was calculated at the same time. MAIN OUTCOME MEASURES: Purity and density of SCs cultured with various methods in the three groups for 21 days. RESULTS: ① Isolation and proliferation of SCs: In the group 1, they increased in number after 4 days and both purity and density of cultured SCs were significantly higher than those from group 2. In the group 2, there were few fibroblasts. In the group 3, both purity and density of cultured SCs were remarkably higher than in those from groups 1 or 2. Then optimal proliferation was soon seen and the rapid expansion of SC populations suppressed the development of contaminating fibroblasts. On the 21st day, SCs proliferated to achieve maximal density and were too crowded to be counted. With Chi-square test, the data of the purity and the density were analyzed from groups 1 to 3, the result indicated χ2=430.47, P < 0.05. ② Characterization and proliferation rate of SCs: Immunostaining for S100 protein was evident in the cell soma and the processes of all three groups in cultures of SCs. SCs in vitro demonstrated typical bi- or tri-polar morphology, had oval nuclei, and stained brightly for S100. The proliferation rate of SCs was assessed with double fluorescence staining for BrdU and S100 on the 21st day of all three groups in cultures. About 40%-50% of the total SCs in the each group showed BrdU incorporation. CONCLUSION: The method is to use predegeneration in vivo, differential speed culture supplemented with the penicillin-streptomycin in low concentration, and changing of the concentration of FBS in the BS medium from 0 to 100 mL/L. This method allows remarkable suppression of fibroblast growth and attainment of SC proliferation and purity, in a short time, from adult nerves.展开更多
基金supported by the National Natural Science Foundation of China,No.82104795 (to RH)。
文摘Runx2 is a major regulator of osteoblast differentiation and function;however,the role of Runx2 in peripheral nerve repair is unclea r.Here,we analyzed Runx2expression following injury and found that it was specifically up-regulated in Schwann cells.Furthermore,using Schwann cell-specific Runx2 knocko ut mice,we studied peripheral nerve development and regeneration and found that multiple steps in the regeneration process following sciatic nerve injury were Runx2-dependent.Changes observed in Runx2 knoc kout mice include increased prolife ration of Schwann cells,impaired Schwann cell migration and axonal regrowth,reduced re-myelination of axo ns,and a block in macrophage clearance in the late stage of regeneration.Taken together,our findings indicate that Runx2 is a key regulator of Schwann cell plasticity,and therefore peripheral nerve repair.Thus,our study shows that Runx2 plays a major role in Schwann cell migration,re-myelination,and peripheral nerve functional recovery following injury.
基金supported by the National Natural Science Foundation of China,Nos.31730031,32130060the National Natural Science Foundation of China,No.31971276(to JH)+1 种基金the Natural Science Foundation of Jiangsu Province,No.BK20202013(to XG)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(Major Program),No.19KJA320005(to JH)。
文摘Schwann cells in peripheral nerves react to traumatic nerve injury by attempting to grow and regenerate.Howeve r,it is unclear what factors play a role in this process.In this study,we searched a GEO database and found that expression of platelet factor 4 was markedly up-regulated after sciatic nerve injury.Platelet factor is an important molecule in cell apoptosis,diffe rentiation,survival,and proliferation.Further,polymerase chain reaction and immunohistochemical staining confirmed the change in platelet factor 4 in the sciatic nerve at different time points after injury.Enzyme-linked immunosorbent assay confirmed that platelet factor 4 was secreted by Schwann cells.We also found that silencing platelet factor 4 decreased the proliferation and migration of primary cultured Schwann cells,while exogenously applied platelet factor 4 stimulated Schwann cell prolife ration and migration and neuronal axon growth.Furthermore,knocking out platelet factor 4 inhibited the prolife ration of Schwann cells in injured rat sciatic nerve.These findings suggest that Schwann cell-secreted platelet factor 4 may facilitate peripheral nerve repair and regeneration by regulating Schwann cell activation and axon growth.Thus,platelet factor 4 may be a potential therapeutic target for traumatic peripheral nerve injury.
基金supported by the National Natural Science Foundation of China,No.81870975(to SZ)。
文摘Exosomes exhibit complex biological functions and mediate a variety of biological processes,such as promoting axonal regeneration and functional recove ry after injury.Long non-coding RNAs(IncRNAs)have been reported to play a crucial role in axonal regeneration.Howeve r,the role of the IncRNA-microRNAmessenger RNA(mRNA)-competitive endogenous RNA(ceRNA)network in exosome-mediated axonal regeneration remains unclear.In this study,we performed RNA transcriptome sequencing analysis to assess mRNA expression patterns in exosomes produced by cultured fibroblasts(FC-EXOs)and Schwann cells(SCEXOs).Diffe rential gene expression analysis,Gene Ontology analysis,Kyoto Encyclopedia of Genes and Genomes analysis,and protein-protein intera ction network analysis were used to explo re the functions and related pathways of RNAs isolated from FC-EXOs and SC-EXOs.We found that the ribosome-related central gene Rps5 was enriched in FC-EXOs and SC-EXOs,which suggests that it may promote axonal regeneration.In addition,using the miRWalk and Starbase prediction databases,we constructed a regulatory network of ceRNAs targeting Rps5,including 27 microRNAs and five IncRNAs.The ceRNA regulatory network,which included Ftx and Miat,revealed that exsosome-derived Rps5 inhibits scar formation and promotes axonal regeneration and functional recovery after nerve injury.Our findings suggest that exosomes derived from fibro blast and Schwann cells could be used to treat injuries of peripheral nervous system.
基金The study was supported by Guangdong Natural Science Foundation(Grant Numbers 2020A1515010014,2022A1515012411)Science and Technology Key Project for People’s Livelihood of Guangzhou,China(Grant Number 202206010060)+1 种基金Guangzhou Science and Technology Bureau Basic Research Project(SL2024A03J01288)Innovative Project of Children’s Research Institute,Guangzhou Women and Children’s Medical Center,China(Grant Numbers Pre-NSFC-2019-002,NKE PRE-2019-015).
文摘Background:During Enterovirus type 71(EV71)infection,the structural viral protein 1(VP1)activates endoplasmic reticulum(ER)stress associated with peripheral myelin protein 22(PMP22)accumulation and induces autophagy.However,the specific mechanism behind this process remains elusive.Methods:In this research,we used the VP1-overexpressing mouse Schwann cells(SCs)models co-transfected with a PMP22 silencing or Autocrine motility factor receptor(AMFR/gp78)overexpressing vector to explore the regulation of gp78 on PMP22 and its relationship with autophagy and apoptosis.Results:The activity of gp78 could be influenced by EV71-VP1,leading to a decrease in the ubiquitination and degradation of PMP22,resulting in PMP22 accumulation in ER.In VP1-overexpressing mouse SCs,all three ER stress sensors,including pancreatic endoplasmic reticulum kinase(PERK),activating transcription factor 6(ATF6)and inositol-requiring enzyme 1(IRE1)and the related downstream signals(C/EBP-homologous protein(CHOP)and Caspase 12)were activated,as well as the ER-resident chaperone Glucose-regulated protein 78(GRP78).In addition,VP1 upregulated the autophagy marker Microtubule-associated protein 1 light chain 3 beta(LC3B),while PMP22 silencing or gp78 overexpression reversed the phenomenon.Meanwhile,PMP22 silencing or gp78 overexpression increased proliferation of EV71-VP1-transfected mouse SCs.Conclusion:Gp78 could regulate PMP22 accumulation through ubiquitination degradation and cause ER stress and autophagy in EV71-VP1-overexpressing mouse SCs.Therefore,the gp78/PMP22/ER stress axis might emerge as a promising therapeutic target for myelin and neuronal damage induced by EV71 infection.
基金supported by the National Natural Science Foundation of China,No. 81801213 (to BP)Xuzhou Special Fund for Promoting Scientific and Technological Innovation,Nos. KC21177 (to BP),KC21195 (to HF)Science and Technology Project of Yili Kazak Autonomous Prefecture,No. YZ2019D006 (to HF)。
文摘Research has shown that long-chain noncoding RNAs(lncRNAs) are involved in the regulation of a variety of biological processes, including peripheral nerve regeneration, in part by acting as competing endogenous RNAs. c-Jun plays a key role in the repair of peripheral nerve injury. However, the precise underlying mechanism of c-Jun remains unclear. In this study, we performed microarray and bioinformatics analysis of mouse crush-injured sciatic nerves and found that the lncRNA Pvt1 was overexpressed in Schwann cells after peripheral nerve injury. Mechanistic studies revealed that Pvt1 increased c-Jun expression through sponging miRNA-214. We overexpressed Pvt1 in Schwann cells cultured in vitro and found that the proliferation and migration of Schwann cells were enhanced, and overexpression of miRNA-214 counteracted the effects of Pvt1 overexpression on Schwann cell proliferation and migration. We conducted in vivo analyses and injected Schwann cells overexpressing Pvt1 into injured sciatic nerves of mice. Schwann cells overexpressing Pvt1 enhanced the regeneration of injured sciatic nerves following peripheral nerve injury and the locomotor function of mice was improved. Our findings reveal the role of lncRNAs in the repair of peripheral nerve injury and highlight lncRNA Pvt1 as a novel potential treatment target for peripheral nerve injury.
基金supported by the National Natural Science Foundation of China,Nos.81772094(to ZBC),81974289(to ZBC)the Key Research and Development Program of Hubei Province,No.2020BCB031(to ZBC)Natural Science Foundation of Hubei Province,No.2020CFB433(to YTL).
文摘Circular RNAs(circRNAs)play a vital role in diabetic peripheral neuropathy.However,their expression and function in Schwann cells in individuals with diabetic peripheral neuropathy remain poorly understood.Here,we performed protein profiling and circRNA sequencing of sural nerves in patients with diabetic peripheral neuropathy and controls.Protein profiling revealed 265 differentially expressed proteins in the diabetic peripheral neuropathy group.Gene Ontology indicated that differentially expressed proteins were mainly enriched in myelination and mitochondrial oxidative phosphorylation.A real-time polymerase chain reaction assay performed to validate the circRNA sequencing results yielded 11 differentially expressed circRNAs.circ_0002538 was markedly downregulated in patients with diabetic peripheral neuropathy.Further in vitro experiments showed that overexpression of circ_0002538 promoted the migration of Schwann cells by upregulating plasmolipin(PLLP)expression.Moreover,overexpression of circ_0002538 in the sciatic nerve in a streptozotocin-induced mouse model of diabetic peripheral neuropathy alleviated demyelination and improved sciatic nerve function.The results of a mechanistic experiment showed that circ_0002538 promotes PLLP expression by sponging miR-138-5p,while a lack of circ_0002538 led to a PLLP deficiency that further suppressed Schwann cell migration.These findings suggest that the circ_0002538/miR-138-5p/PLLP axis can promote the migration of Schwann cells in diabetic peripheral neuropathy patients,improving myelin sheath structure and nerve function.Thus,this axis is a potential target for therapeutic treatment of diabetic peripheral neuropathy.
基金supported by Military Medical Science&Technology Youth Training Program,No. 19QNP005President Foundation of Nanfang Hospital,Southern Medical University,No. 2020B028 (both to JY)。
文摘Studies have shown that human hair keratin(HHK) has no antigenicity and excellent mechanical properties. Schwann cells, as unique glial cells in the peripheral nervous system, can be induced by interleukin-1β to secrete nerve growth factor, which promotes neural regeneration. Therefore, HHK with Schwann cells may be a more effective approach to repair nerve defects than HHK without Schwann cells. In this study, we established an artificial nerve graft by loading an HHK skeleton with activated Schwann cells. We found that the longitudinal HHK microfilament structure provided adhesion medium, space and direction for Schwann cells, and promoted Schwann cell growth and nerve fiber regeneration. In addition, interleukin-1β not only activates Schwann cells, but also strengthens their activity and increases the expression of nerve growth factors. Activated Schwann cells activate macrophages, and activated macrophages secrete interleukin-1β, which maintains the activity of Schwann cells. Thus, a beneficial cycle forms and promotes nerve repair. Furthermore, our studies have found that the newly constructed artificial nerve graft promotes the improvements in nerve conduction function and motor function in rats with sciatic nerve injury, and increases the expression of nerve injury repair factors fibroblast growth factor 2 and human transforming growth factor B receptor 2. These findings suggest that this artificial nerve graft effectively repairs peripheral nerve injury.
基金supported by the National Natural Science Foundation of China,No.81771351the National Key R&D Program of China,No.2017YFA0105802+1 种基金the Joint Research Fund Liaoning-Shenyang National Laboratory for Materials Science,No.2019JH3/30100022the National Science Foundation for Post-doctoral Scientists of China,No.2018M641732(all to QA and LLW)。
文摘The functional properties of endogenous Schwann cells(SCs)during nerve repair are dynamic.Optimizing the functional properties of SCs at different stages of nerve repair may have therapeutic benefit in improving the repair of damaged nerves.Previous studies showed that miR-221-3p promotes the proliferation and migration of SCs,and miR-338-3p promotes the myelination of SCs.In this study,we established rat models of sciatic nerve injury by bridging the transected sciatic nerve with a silicone tube.We injected a miR-221 lentiviral vector system together with a doxycycline-inducible Tet-On miR-338 lentiviral vector system into the cavity of nerve conduits of nerve stumps to sequentially regulate the biological function of endogenous SCs at different stages of nerve regeneration.We found that the biological function of SCs was sequentially regulated,the diameter and density of myelinated axons were increased,the expression levels of NF200 and myelin basic protein were increased,and the function of injured peripheral nerve was improved using this system.miRNA Target Prediction Database prediction,Nanopore whole transcriptome sequencing,quantitative PCR,and dual luciferase reporter gene assay results predicted and verified Cdkn1b and Nrp1 as target genes of miR-221-3p and miR-338-3p,respectively,and their regulatory effects on SCs were confirmed in vitro.In conclusion,here we established a new method to enhance nerve regeneration through sequential regulation of biological functions of endogenous SCs,which establishes a new concept and model for the treatment of peripheral nerve injury.The findings from this study will provide direct guiding significance for clinical treatment of sciatic nerve injury.
基金supported by the National Natural Sclence Foundation of China in 2021No.82171213+1 种基金the Natural Science Foundation of Fujian Province in 2019No.2019J01289 (both to DSL)
文摘The trigeminal root entry zone is the zone at which the myelination switches from peripheral Schwann cells to central oligodendrocytes.Its special anatomical and physiological structure renders it susceptible to nerve injury.The etiology of most primary trigeminal neuralgia is closely related to microvascular compression of the trigeminal root entry zone.This study aimed to develop an efficient in vitro model mimicking the glial environment of trigeminal root entry zone as a tool to investigate the effects of glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor on the structural and functional integrity of trigeminal root entry zone and modulation of cellular interactions.Primary astrocytes and Schwann cells isolated from trigeminal root entry zone of postnatal rats were inoculated into a two-well silicon culture insert to mimic the trigeminal root entry zone microenvironment and treated with glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor.In monoculture,glial cell line-derived neurotrophic factor promoted the migration of Schwann cells,but it did not have effects on the migration of astrocytes.In the co-culture system,glial cell line-derived neurotrophic factor promoted the bidirectional migration of astrocytes and Schwann cells.Brain-derived neurotrophic factor markedly promoted the activation and migration of astrocytes.However,in the co-culture system,brain-derived neurotrophic factor inhibited the migration of astrocytes and Schwann cells to a certain degree.These findings suggest that glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor are involved in the regulation of the astrocyte-Schwann cell interaction in the co-culture system derived from the trigeminal root entry zone.This system can be used as a cell model to study the mechanism of glial dysregulation associated with trigeminal nerve injury and possible therapeutic interventions.
基金supported by a grant from Student’s Platform for Innovation and Entrepreneurship Training Program in China,No.201610062009the National Natural Science Foundation of China(Key Program),No.81330042+1 种基金a grant from the Special Program for Sino-Russian Joint Research Sponsored by the Ministry of Science and Technology,China,No.2014DFR31210a grant from the Key Program Sponsored by the Tianjin Science and Technology Committee of China,No.13RCGFSY19000,14ZCZDSY00044
文摘Schwann cells play a critical role in peripheral nerve regeneration through dedifferentiation and proliferation. In a previous study, we performed microarray analysis of the sciatic nerve after injury. Accordingly, we predicted that long non-coding RNA NONMMUG014387 may promote Schwann cell proliferation after peripheral nerve injury, as bioinformatic analysis revealed that the target gene of NONMMUG014387 was collagen triple helix repeat containing 1(Cthrc1). Cthrc1 may promote cell proliferation in a variety of cells by activating Wnt/PCP signaling. Nonetheless, bioinformatic analysis still needs to be verified by biological experiment. In this study, the candidate long non-coding RNA, NONMMUG014387, was overexpressed in mouse Schwann cells by recombinant adenovirus transfection. Plasmid p HBAd-MCMV-GFP-NONMMUG014387 and p HBAd-MCMV-GFP were transfected into Schwann cells. Schwann cells were divided into three groups: control(Schwann cells without intervention), Ad-GFP(Schwann cells with GFP overexpression), and Ad-NONMMUGO148387(Schwann cells with GFP and NONMMUGO148387 overexpression). Cell Counting Kit-8 assay was used to evaluate proliferative capability of mouse Schwann cells after NONMMUG014387 overexpression. Polymerase chain reaction and western blot assay were performed to investigate target genes and downstream pathways of NONMMUG014387. Cell proliferation was significantly increased in Schwann cells overexpressing lnc RNA NONMMUG014387 compared with the other two groups. Further, compared with the control group, m RNA and protein levels of Cthrc1, Wnt5 a, ROR2, Rho A, Rac1, JNK, and ROCK were visibly up-regulated in the Ad-NONMMUGO148387 group. Our findings confirm that long non-coding RNA NONMMUG014387 can promote proliferation of Schwann cells surrounding the injury site through targeting Cthrc1 and activating the Wnt/PCP pathway.
基金This work was also supported by the National Natural Science Foundation of China,No.81901365(to WRQ)Jilin Science and Technology Agency Funds in China,Nos.20180101118JC(to RL),20180520115JH(to BPC)and 20190103076JH(to WRQ).
文摘Peripheral nerve injury(PNI)is common and,unlike damage to the central nervous system injured nerves can effectively regenerate depending on the location and severity of injury.Peripheral myelinating glia,Schwann cells(SCs),interact with various cells in and around the injury site and are important for debris elimination,repair,and nerve regeneration.Following PNI,Wallerian degeneration of the distal stump is rapidly initiated by degeneration of damaged axons followed by morphologic changes in SCs and the recruitment of circulating macrophages.Interaction with fibroblasts from the injured nerve microenvironment also plays a role in nerve repair.The replication and migration of injury-induced dedifferentiated SCs are also important in repairing the nerve.In particular,SC migration stimulates axonal regeneration and subsequent myelination of regenerated nerve fibers.This mobility increases SC interactions with other cells in the nerve and the exogenous environment,which influence SC behavior post-injury.Following PNI,SCs directly and indirectly interact with other SCs,fibroblasts,and macrophages.In addition,the inter-and intracellular mechanisms that underlie morphological and functional changes in SCs following PNI still require further research to explain known phenomena and less understood cell-specific roles in the repair of the injured peripheral nerve.This review provides a basic assessment of SC function post-PNI,as well as a more comprehensive evaluation of the literature concerning the SC interactions with macrophages and fibroblasts that can influence SC behavior and,ultimately,repair of the injured nerve.
基金supported by the National Natural Science Foundation of China,No.81970820(to HX)
文摘Schwann cell proliferation,migration and remyelination of regenerating axons contribute to regeneration after peripheral nervous system injury.Lithium promotes remyelination by Schwann cells and improves peripheral nerve regeneration.However,whether lithium modulates other phenotypes of Schwann cells,especially their proliferation and migration remains elusive.In the current study,primary Schwann cells from rat sciatic nerve stumps were cultured and exposed to 0,5,10,15,or 30 mM lithium chloride(LiCl)for 24 hours.The effects of LiCl on Schwann cell proliferation and migration were examined using the Cell Counting Kit-8,5-ethynyl-2′-deoxyuridine,Transwell and wound healing assays.Cell Counting Kit-8 and 5-ethynyl-2′-deoxyuridine assays showed that 5,10,15,and 30 mM LiCl significantly increased the viability and proliferation rate of Schwann cells.Transwell-based migration assays and wound healing assays showed that 10,15,and 30 mM LiCl suppressed the migratory ability of Schwann cells.Furthermore,the effects of LiCl on the proliferation and migration phenotypes of Schwann cells were mostly dose-dependent.These data indicate that lithium treatment significantly promotes the proliferation and inhibits the migratory ability of Schwann cells.This conclusion will inform strategies to promote the repair and regeneration of peripheral nerves.All of the animal experiments in this study were ethically approved by the Administration Committee of Experimental Animal Center of Nantong University,China(approval No.20170320-017)on March 2,2017.
基金Research in the Xu laboratory is supported by NIH 1R01100531,1R01 NS103481Merit Review Award I01 BX002356,I01 BX003705,I01 RX002687 from the U.S.Department of Veterans AffairsMari Hulman George Endowment Funds.
文摘Biomaterial bridging provides physical substrates to guide axonal growth across the lesion.To achieve efficient directional guidance,combinatory strategies using permissive matrix,cells and trophic factors are necessary.In the present study,we evaluated permissive effect of poly(acrylonitrile-co-vinyl chloride)guidance channels filled by different densities of laminin-precoated unidirectional polypropylene filaments combined with Schwann cells,and glial cell line-derived neurotrophic factor for axonal regeneration through a T10 hemisected spinal cord gap in adult rats.We found that channels with filaments significantly reduced the lesion cavity,astrocytic gliosis,and inflammatory responses at the graft-host boundaries.The laminin coated low density filament provided the most favorable directional guidance for axonal regeneration which was enhanced by co-grafting of Schwann cells and glial cell line-derived neurotrophic factor.These results demonstrate that the combinatorial strategy of filament-filled guiding scaffold,adhesive molecular laminin,Schwann cells,and glial cell line-derived neurotrophic factor,provides optimal topographical cues in stimulating directional axonal regeneration following spinal cord injury.This study was approved by Indiana University Institutional Animal Care and Use Committees(IACUC#:11011)on October 29,2015.
基金Technology Project of Nantong of China,Nos.JC2020052(to XSG),JCZ19087(to XSG)the National Natural Science Foundation of China,Nos.81873742(to KFK),81901195(to JBS),81502867(to TX),82073627(to TX).
文摘Autophagy has been shown to play an important role in Parkinson’s disease.We hypothesized that skin-derived precursor cells exhibit neuroprotective effects in Parkinson’s disease through affecting autophagy.In this study,6-hydroxydopamine-damaged SH-SY5Y cells were pretreated with a culture medium containing skin-derived precursors differentiated into Schwann cells(SKP-SCs).The results showed that the SKP-SC culture medium remarkably enhanced the activity of SH-SY5Y cells damaged by 6-hydroxydopamine,reduced excessive autophagy,increased tyrosine hydroxylase expression,reducedα-synuclein expression,reduced the autophagosome number,and activated the PI3K/AKT/mTOR pathway.Autophagy activator rapamycin inhibited the effects of SKP-SCs,and autophagy inhibitor 3-methyladenine had the opposite effect.These findings confirm that SKP-SCs modulate the PI3K/AKT/mTOR pathway to inhibit autophagy,thereby exhibiting a neuroprotective effect in a cellular model of Parkinson’s disease.This study was approved by the Animal Ethics Committee of Laboratory Animal Center of Nantong University(approval No.S20181009-205)on October 9,2018.
基金This study was supported by the National Natural Science Foundation of China,Nos.31900718(to ZYW),31872773(to GC)the National Key Research and Development Program of China,No.2017YFA0104704(to GC)+2 种基金Basic Research Program of the Education Department of Jiangsu Province of China,Nos.19KJB180024(to ZYW),18KJB180020(to WXS)Postdoctoral Science Foundation of China,No.2019M651925(to ZYW),Jiangsu Students’Platform for Innovation and Entrepreneurship Training Program of China,No.201810304031Z(to YJD)Six Talent Peaks Project in Jiangsu Province of China,No.WSN-007(to WXS).
文摘Pannexin 1(Panx 1),as a large-pore membrane channel,is highly permeable to ATP and other signaling molecules.Previous studies have demonstrated the expression of Panx 1 in the nervous system,including astrocytes,microglia,and neurons.However,the distribution and function of Panx 1 in the peripheral nervous system are not clear.Blocking the function of Panx 1 pharmacologically(carbenoxolone and probenecid)or with small interfering RNA targeting pannexins can greatly reduce hypotonicity-induced ATP release.Treatment of Schwann cells with a Ras homolog family member(Rho)GTPase inhibitor and small interfering RNA targeting Rho or cytoskeleton disrupting agents,such as nocodazole or cytochalasin D,revealed that hypotonicity-induced ATP release depended on intracellular RhoA and the cytoskeleton.These findings suggest that Panx 1 participates in ATP release in Schwann cells by regulating RhoA and the cytoskeleton arrangement.This study was approved by the Animal Ethics Committee of Nantong University,China(No.S20180806-002)on August 5,2018.
文摘Peripheral nerve injury is a common neurodegenerative disease,which causes disability and a huge economic burden for patients.MicroRNAs(miRNAs)have been acknowledged as major regulators and therapeutic targets of neurological disease.Thus,the functional studies of miRNAs in neurological disease will contribute to discover new therapeutic targets for peripheral nerve injury.Sprague Dawley rats treated sciatic nerve surgical injury were regarded as peripheral nerve injury model in vivo.The expression of miR-494-3p and Kruppel like factor7(KLF7)were measured by Real-time quantitative polymerase chain reaction(RT-qPCR)assay.In addition,western blot analysis was conducted to measure the protein levels of KLF7,Bax,Bcl-2,and C-caspase 3.Cell viability and apoptosis were detected in Schwann cells by EdU stain and flow cytometry,respectively.The interaction between miR-494-3p and KLF7 was investigated by dual-luciferase reporter assay.The expression of miR-494-3p was reduced at the beginning,but KLF7 was enhanced in Sprague Dawley rats with peripheral nerve injury.Knockdown of miR-494-3p promoted cell proliferation and suppressed apoptosis,while overexpression of miR-494-3p or silencing KLF7 led to opposite results.Moreover,the upregulation of KLF7 attenuated miR-494-3p overexpression-induced suppressive effects on viability and promotion of apoptosis in Schwann cells.MiR-494-3p negatively regulates KLF7 in Schwann cells to mediate proliferation and apoptosis.
基金the National Natural Science Foundation of China, No. 30070775 a grant from the Scientific Research Foundation of Liaoning Department of Education, No. 2005L5371
文摘BACKGROUND: Animal experiments and clinical studies about tissue engineering method applied to repair nerve injury mainly focus on seeking ideal artificial nerve grafts, nerve conduit and seed cells. Autologous nerve, allogeneic nerve and xenogeneic nerve are used to bridge nerve defects, it is one of the methods to promote the repair of nerve injury by culturing and growing Schwann cells, which can secrete various neurotrophic factor activities, in the grafts. OBJECTIVE: To observe the effect of acellular nerve grafts co-cultured with Schwann cells in repairing defects of sciatic nerve. DESIGN: An observational comparative study. SETTING: Tissue Engineering Laboratory of China Medical University. MATERIALS: The experiment was carried out in the Tissue Engineering Laboratory of China Medical University between April 2004 and April 2005. Forty neonatal Sprague-Dawley rats of 5-8 days (either males or females) and 24 male Wistar rats of 180-220 g were provided by the experimental animal center of China Medical University. METHODS: ① Culture of Schwann cells: The bilateral sciatic nerves and branchial plexus were isolated from the 40 neonatal SD rats. The sciatic nerves were enzymatically digested with collagenase and dispase, isolatd, purified and cultured with the method of speed-difference adhersion, and identified with the SABC immunohistochemical method. ② Model establishment: In vitro Schwann cells were microinjected into 10-mm long acellular nerve grafts repairing a surgically created gap in the rat sciatic nerve. According to the different grafted methods, the animals were randomly divided into three groups: autografts (n=8), acellular nerve grafts (n=8), or acellular nerve grafts with Schwann cells (n=8). ③ The regenerated nerve fiber number and average diameter of myeline sheath after culture were statistically anlayzed. MAIN OUTCOME MEASURES: ① The regenerated nerve ultrastructure, total number and density of myelinated nerve fibers, and the thickness of myeline sheath were observed under electron microscope. ② The images were processed with the Mias-1000 imaging analytical system to calculate the number of myelinated nerve fibers, and the thickness of myeline sheath. RESULTS: All the 24 Wistar rats were involved in the analysis of results. ① Results observed under transmission electron microscope: The regenerated myelinated nerve fibers in the group of acellular nerve grafts with Schwann cells were more even than those in the group of acellular nerve grafts, the number of myelinated nerve fibers and thickness of myelin sheath were close to those in the allografts group (P > 0.05), but significantly different from those in the group of acellular nerve grafts (P < 0.05). ② Results observed under scanning electron microscope: A great amount of Schwann cells with two polars were observed in the group of grafts with Schwann cells, the feature of cultured Schwann cells showed shoulder by shoulder, head to head. ③ The number of myelinated nerve fibers and thickness of myelin sheath analyzed by Mias-1000 imaging system in the group of acellular nerve grafts with Schwann cells were close to those in the autografts group (P > 0.05), but significantly different from those in the group of acellular nerve grafts (P < 0.05). CONCLUSION: Host axonal regeneration is significantly increased after implant of acellular nerve grafts. Acellular nerve grafts with Schwann cells offers a novel approach for repairing the gap of nerve defect.
文摘OBJECTIVE The proteasome inhibitor bortezomib(BTZ)is a first-line anti-multi⁃ple myeloma drug.BTZ-induced peripheral neu⁃ropathy(BIPN)is a main adverse effect that char⁃acterized by neuropathic pain.There is still no strategy to prevent or treat BIPN,attributed to the unidentified mechanisms underlying BIPN.Previous studies suggested that BTZ impairs Schwann cells and thus leads to axonal demye⁃lination,whereas it remained not fully understood how BTZ cause Schwann cell death.It was observed that BTZ upregulates the autophagy marker LC3-Ⅱprotein in Schwann cells.However,it remains unclear whether BTZ causes autopha⁃gy-lysosome dysfunction in Schwann cells.METHODS The male C57BL/6 mice were intra⁃venous injection of BTZ(1 mg·kg-1 per day,twice weekly for a total of 4 weeks).The paw withdraw⁃al latency was tested by the Von Frey test and Hargreaves test to reflect the neuropathic pain.The conduction velocity and the action potential amplitude of the tail nerve were tested by neuro⁃physiological assessment to reflect peripheral nerve function.The histomorphology of the sciat⁃ic nerves was detected by immunofluorescence and transmission electron microscopy to reflect the demyelination and axonal degeneration.The RSC96 cells,the Schwann cell-like immortal cells,were cultured and exposed to BTZ.The lysosomal function was determined by Lyso⁃Tracker and DQ-BSA staining.Autophagy-relat⁃ed proteins,including p62 and LC3,and lysosom⁃al hydrolase cathepsin B were determined by Western blotting.RESULTS①BTZ induced mechano-allodynia,neurological conduction abnormalities of the tail nerve,demyelination and axonal degeneration of the sciatic nerves.②BTZ caused lysosomal dysfunction,resulting in the blockade of autophagy flux in Schwann cells and sciatic nerves.③The lysosomal activator Torin1 reversed lysosomal dysfunction caused by BTZ in Schwann cells.④Torin1 improved BTZ-induced mechano-allodynia and demyelination of sciatic nerves.CONCLUSION BTZ led to lyso⁃somal dysfunction in Schwann cells and contrib⁃uted to BIPN.Lysosomal activation could be a promising strategy for BIPN intervention.
基金supported by the Key University Natural Science Research Project of Anhui Province of China,No.KJ2016A870
文摘Schwann cells play an important role in the peripheral nervous system, especially in nerve repair following injury, so artificial nerve regeneration requires an effective technique for obtaining purified Schwann cells. In vivo and in vitro pre-degeneration of peripheral nerves have been shown to obtain high-purity Schwann cells. We believed that in vitro pre-degeneration was simple and controllable, and available for the clinic. Thus, we co-cultured the crushed sciatic nerves with bone marrow-derived cells in vitro. Results demonstrated that, 3 hours after injury, a large number of mononuclear cells moved to the crushed nerves and a large number of bone marrow-derived cells infiltrated the nerve segments. These changes promoted the degradation of the nerve segments, and the dedifferentiation and proliferation of Schwann cells. Neural cell adhesion molecule and glial fibrillary acidic protein expression were detected in the crushed nerves. Schwann cell yield was 9.08 ± 2.01 × 104/mg. The purity of primary cultured Schwann cells was 88.4 ± 5.79%. These indicate a successful new method for obtaining Schwann cells of high purity and yield from adult crushed sciatic nerve using bone marrow-derived cells.
基金the Natural Science Foundation of Heilongjiang Province, No. D200559
文摘BACKGROUND: Schwann cells (SCs) are neuroglial cells of peripheral nerve and play a key role in repairing peripheral nerve injury; therefore, it provides an important evidence for transplantation of SCs which are characterized by active proliferation and adult high-purity in vitro after nerve injury in clinic, and also develops a new therapeutic way for nerve injury. OBJECTIVE: To investigate an effective technique for isolating adult activated Schwann cells. DESIGN: Controlled observational study. SETTING: Mudanjiang Medical College. MATERIALS: The experiment was completed at the Department of Medical Genetics of Harbin Medical University from March 2003 to April 2005. Health female Wistar rats, aged 2 months, weighting 150-160 g, were randomly divided into 3 groups with 5 in each group. METHODS: The right sciatic nerves from 15 Wistar rats were exposed and transected at the mid thigh under pentobarbital anesthesia (4 mg/kg, i.p). Seven days later, the distal segments of the predegenerated nerves were removed and used to produce adult Schwann cell cultures. The distal segment of the predegenerated nerve, 20 mm in length, was resected. The nerve was cut into pieces 1 mm in length and incubated for 3 hours under CO2 at 37 ℃ with an enzyme mixture of 0.05% collagenase/dispase. Rats were divided into 3 groups: ① Group 1: The nerve fragments were explanted in poly-L-lysine and laminin-coated dishes with BS medium from the 1st to the 6th day. On the 6th day, the fragments were removed into a new poly-L-lysine-laminin-coated dish and the BS medium was changed to BS with 10% FBS. The nerve fragments were replaced repeatedly in the same way in new dishes on the 12th and the 18th days. ② Group 2: For the first 3 days, the nerve fragments were fed with BS with 10% FBS. This medium was changed to BS medium on the third day. The nerve fragments were removed to another dish on day 6 and BS medium was changed to BS with 25 mL/L FBS. Hereafter the culture method was the same as for group 1. ③ Group 3: For the first 6 days, nerve fragments were incubated in a dish not coated with poly-L-lysine and laminin, in BS medium supplemented with 8×107 U/L of penicillin-streptomycin. On the 6th day, the nerve fragments were removed to a poly-L-lysine-laminin-coated dish and cultured in BS with 25 mL/L FBS. On the 12th day, the nerve fragments were explanted a second dish and fed with BS containing 100 mL/L FBS. On the 18th day, they were explanted to a third poly-L-lysine-laminin-coated dish. SCs were obtained from all 3 dishes on the 21st day. Finally, purity and density of SCs were identified and proliferation index was calculated at the same time. MAIN OUTCOME MEASURES: Purity and density of SCs cultured with various methods in the three groups for 21 days. RESULTS: ① Isolation and proliferation of SCs: In the group 1, they increased in number after 4 days and both purity and density of cultured SCs were significantly higher than those from group 2. In the group 2, there were few fibroblasts. In the group 3, both purity and density of cultured SCs were remarkably higher than in those from groups 1 or 2. Then optimal proliferation was soon seen and the rapid expansion of SC populations suppressed the development of contaminating fibroblasts. On the 21st day, SCs proliferated to achieve maximal density and were too crowded to be counted. With Chi-square test, the data of the purity and the density were analyzed from groups 1 to 3, the result indicated χ2=430.47, P < 0.05. ② Characterization and proliferation rate of SCs: Immunostaining for S100 protein was evident in the cell soma and the processes of all three groups in cultures of SCs. SCs in vitro demonstrated typical bi- or tri-polar morphology, had oval nuclei, and stained brightly for S100. The proliferation rate of SCs was assessed with double fluorescence staining for BrdU and S100 on the 21st day of all three groups in cultures. About 40%-50% of the total SCs in the each group showed BrdU incorporation. CONCLUSION: The method is to use predegeneration in vivo, differential speed culture supplemented with the penicillin-streptomycin in low concentration, and changing of the concentration of FBS in the BS medium from 0 to 100 mL/L. This method allows remarkable suppression of fibroblast growth and attainment of SC proliferation and purity, in a short time, from adult nerves.
