Microglia-organized scar-free spinal cord repair in neonatal mice.

Spinal cord injury in mammals is thought to trigger scar formation with little regeneration of axons1-4. Here we show that a crush injury to the spinal cord in neonatal mice leads to scar-free healing that permits the growth of long projecting axons through the lesion. Depletion of microglia in neonatal mice disrupts this healing process and stalls the regrowth of axons, suggesting that microglia are critical for orchestrating the injury response. Using single-cell RNA sequencing and functional analyses, we find that neonatal microglia are transiently activated and have at least two key roles in scar-free healing. First, they transiently secrete fibronectin and its binding proteins to form bridges of extracellular matrix that ligate the severed ends of the spinal cord. Second, neonatal-but not adult-microglia express several extracellular and intracellular peptidase inhibitors, as well as other molecules that are involved in resolving inflammation. We transplanted either neonatal microglia or adult microglia treated with peptidase inhibitors into spinal cord lesions of adult mice, and found that both types of microglia significantly improved healing and axon regrowth. Together, our results reveal the cellular and molecular basis of the nearly complete recovery of neonatal mice after spinal cord injury, and suggest strategies that could be used to facilitate scar-free healing in the adult mammalian nervous system.

Systematic analysis of miRNAs in patients with postmenopausal osteoporosis.

MicroRNAs (miRNAs) represent RNA species found in serum. Many miRNAs were observed that were related to osteoporosis and osteopenia. However, expression and function analysis of miRNAs in postmenopausal osteoporosis (PMOP) remain unaddressed. We first compared the miRNA expression of blood samples in postmenopausal women with osteopenia or with osteoporosis via analysis of GSE64433. Bioinformatics analyses were conducted to get the key miRNAs and their functions and pathways. 331 miRNAs were being identified as differentially expressed miRNAs. Among these, 122 miRNA (36.86%) were up-regulated, and the remaining 209 miRNAs (63.14%) were down-regulated. 105 genes were predicted as the targets of these miRNAs. GO enrichment analysis results showed that the miRNAs mainly enriched in DNA binding, ATP binding, gene expression, regulation of the apoptotic process, chromatin binding, and protein kinase binding. KEGG enrichment analysis results demonstrated that the miRNAs mainly enriched in the TGF beta signaling pathway, wnt signaling pathway, JAK-STAT signaling pathway, and androgen receptor signaling pathway. This study identified the abundant differentially expressed miRNAs in the blood samples of postmenopausal women with osteopenia or with osteoporosis. This study may contribute to getting new diagnostic and therapeutic strategies for PMOP.

Signatures of altered long noncoding RNAs and messenger RNAs expression in the early acute phase of spinal cord injury.

Spinal cord injury (SCI) is a highly severe disease and it can lead to the destruction of the motor and sensory function resulting in temporary or permanent disability. Long noncoding RNAs (lncRNAs) are transcripts longer than 200 nt that play a critical role in central nervous system (CNS) injury. However, the exact roles of lncRNAs and messenger RNAs (mRNAs) in the early acute phase of SCI remain to be elucidated. We examined the expression of mRNAs and lncRNAs in a rat model at 2 days after SCI and identified the differentially expressed lncRNAs (DE lncRNAs) and differentially expressed mRNAs (DE mRNAs) using microarray analysis. Subsequently, a comprehensive bioinformatics analysis was also performed to clarify the interaction between DE mRNAs. A total of 3,193 DE lncRNAs and 4,308 DE mRNAs were identified between the injured group and control group. Classification, length distribution, and chromosomal distribution of the dysregulated lncRNAs were also performed. The gene ontology analysis and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were performed to identify the critical biological processes and pathways. A protein-protein interaction (PPI) network indicated that IL6, TOP2A, CDK1, POLE, CCNB1, TNF, CCNA2, CDC20, ITGAM, and MYC were the top 10 core genes. The subnetworks from the PPI network were identified to further elucidate the most significant functional modules of the DE mRNAs. These data may provide novel insights into the molecular mechanism of the early acute phase of SCI. The identification of lncRNAs and mRNAs may offer potential diagnostic and therapeutic targets for SCI.

Correction to: c-Jun Amino-Terminal Kinase is Involved in Valproic Acid-Mediated Neuronal Differentiation of Mouse Embryonic NSCs and Neurite Outgrowth of NSC-Derived Neurons.

In the original version of this article, unfortunately, the images in Fig. 4 and 7 are mixed. The correct version of the Fig.4 and 7 is given below.

The emerging role of long non-coding RNA in spinal cord injury.

Spinal cord injury (SCI) is a significant health burden worldwide which causes permanent neurological deficits, and there are approximately 17,000 new cases each year. However, there are no effective and current treatments that lead to functional recovery because of the limited understanding of the pathogenic mechanism of SCI. In recent years, the biological roles of long non-coding RNAs (lncRNAs) in SCI have attracted great attention from the researchers all over the world, and an increasing number of studies have investigated the regulatory roles of lncRNAs in SCI. In this review, we summarized the biogenesis, classification and function of lncRNAs and focused on the investigations on the roles of lncRNAs involved in the pathogenic processes of SCI, including neuronal loss, astrocyte proliferation and activation, demyelination, microglia activation, inflammatory reaction and angiogenesis. This review will help understand the molecular mechanisms of SCI and facilitate the potential use of lncRNAs as diagnostic markers and therapeutic targets for SCI treatment.

MicroRNA-29a regulates neural stem cell neuronal differentiation by targeting PTEN.

Neural stem cells (NSCs) are self-renewing, pluripotent, and undifferentiated cells which have benefits as candidates for central nervous system (CNS) injury. However, the transplanted NSCs usually maintain their undifferentiated characteristics, or differentiated potentially along the glial lineage after transplantation. MicroRNAs (miRNAs) are small, non-coding RNAs that play key roles in cell differentiation. However, it is unknown whether miR-29a could play a role in the process of NSC's differentiation. Primary NSCs were derived from rat embryonic cortex. Lentiviral vector-mediated miR-29a (LV-miR-29a) and negative control (LV-null) were infected into NSCs. Quantitative real-time PCR was used to detect expression of miR-29a and PTEN. Immunocytochemistry was used to stain neurons, astrocytes, and oligodendrocytes. Dual luciferase assay to study the interaction between miR-29a and PTEN. The current study showed that the expression of miR-29a was upregulated during NSC differentiation, while the expression of PTEN was downregulated during NSC differentiation. After infection with LV-miR-29a, MAP-2-positive neurons significantly increased, and GFAP-positive astrocytes significantly decreased. Furthermore, we demonstrated that PTEN is a molecular target of miR-29a. miR-29a promote the neuronal differentiation and decrease the astrocytes differentiation of NSCs via targeting PTEN. This may give insight into a novel mechanism of NSC differentiation and provide a promising therapeutic target.

Identification and Verification of Candidate Genes Regulating Neural Stem Cells Behavior Under Hypoxia.

BACKGROUND/AIMS: Neural stem cells (NSCs) reside in a hypoxic environment, and hypoxia plays an important role in their development and differentiation. This study aimed to explore the underlying mechanisms by which hypoxia affects NSC behavior. METHODS: In the current study, we downloaded the gene expression dataset GSE68572 and identified the differentially expressed genes (DEGs) by analyzing high-throughput gene expression in hypoxic and normoxic NSCs. Subsequently, we analyzed these data using a combined bioinformatics approach and predicted the microRNAs (miRNAs) targeting the key gene using miRNA databases. Quantitative real-time PCR (qRT-PCR) was used to validate the expression of the top five DEGs. RESULTS: In total, 1347 genes were identified as DEGs. We identified the predominant gene ontology categories and Kyoto Encyclopedia of Genes and Genomes pathways that were significantly over-represented in the hypoxic NSCs. A protein-protein interaction network he identification of miRNAs and their putative targets may offer new diagnostic and therapeutic strategies for liver cancer the top 10 core genes. Vascular endothelial growth factor A (VEGFA) had the highest degree and may be the key gene concerning NSC behavior under hypoxia. Further validation of the top five DEGs by qRT-PCR demonstrated that four DEGs were significantly higher and one DEG was significantly lower in the hypoxic group than in the control group. Seven miRNAs were predicted and proved to target VEGFA. CONCLUSION: This preliminary study can prompt the understanding of the molecular mechanisms by which hypoxia has an impact on NSC behavior and can help to optimize stem cell therapies for central nervous system injuries and diseases.

c-Jun Amino-Terminal Kinase is Involved in Valproic Acid-Mediated Neuronal Differentiation of Mouse Embryonic NSCs and Neurite Outgrowth of NSC-Derived Neurons.

Valproic acid (VPA), an anticonvulsant and mood-stabilizing drug, can induce neuronal differentiation, promote neurite extension and exert a neuroprotective effect in central nervous system (CNS) injuries; however, comparatively little is known regarding its action on mouse embryonic neural stem cells (NSCs) and the underlying molecular mechanism. Recent studies suggested that c-Jun N-terminal kinase (JNK) is required for neurite outgrowth and neuronal differentiation during neuronal development. In the present study, we cultured mouse embryonic NSCs and treated the cells with 1 mM VPA for up to 7 days. The results indicate that VPA promotes the neuronal differentiation of mouse embryonic NSCs and neurite outgrowth of NSC-derived neurons; moreover, VPA induces the phosphorylation of c-Jun by JNK. In contrast, the specific JNK inhibitor SP600125 decreased the VPA-stimulated increase in neuronal differentiation of mouse embryonic NSCs and neurite outgrowth of NSC-derived neurons. Taken together, these results suggest that VPA promotes neuronal differentiation of mouse embryonic NSCs and neurite outgrowth of NSC-derived neurons. Moreover, JNK activation is involved in the effects of VPA stimulation.

The roles of microRNAs in spinal cord injury.

BACKGROUND AND PURPOSE: Spinal cord injury (SCI) involves serious damage that can result in abnormal or absent motor and sensory functions and a disruption of autonomic function, and a series of pathological reactions occur after the injury. As a type of small non-coding RNA, microRNAs (miRNAs) have been verified to inhibit gene expression via post-transcriptional regulation. This review mainly focuses on recent advances regarding the roles of miRNAs following SCI. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were adopted. The studies regarding the roles of miRNAs following SCI were identified through PubMed, Embase and Web of Science. We summarise the changes in expression levels of miRNAs and discuss the roles of miRNAs after SCI. RESULTS: A total of 77 empirical studies meeting the inclusion criteria were identified. Existing studies showed that miRNAs were temporally altered and had effects on apoptosis, inflammation, angiogenesis, astrogliosis, oligodendrocyte development, axonal regeneration and remyelination after SCI. The alteration of miRNAs and the regulative action of pathological reactions can also provide opportunities for potential therapeutic interventions. "miRNA replacement therapy" aims to transfer miRNAs into diseased cells via delivery techniques and improve targeting effectiveness in cells, and this novel therapeutic tool provides a promising technique to promote the repair of SCI and reduces functional deficits. CONCLUSIONS: This review is helpful for understanding the underlying mechanisms of SCI and the potential clinical value of miRNAs. miRNAs have the potential to be attractive tools and targets for novel diagnostic and therapeutic approaches of SCI.

Analysis and experimental validation of genes and their transcription factor prediction in contused rat spinal cord at the intermediate phase.

The intermediate phase of spinal cord injury (SCI) serves as an important target site for therapeutic mediation of SCI. However, there is a lack of insight into the mechanism of the intermediate phase of SCI. The present study aimed to investigate the molecular mechanism and the feasible treatment targets in the intermediate phase of SCI. We downloaded GSE2599 from GEO and identified 416 significant differentially expressed genes (DEGs), including 206 downregulated and 210 upregulated DEGs. Further enrichment analysis of DEGs revealed that many important biological processes and signal pathways were triggered in the injured spinal cord. Furthermore, a protein-protein interaction (PPI) network was constructed and the top 10 high-degree hub nodes were identified. Furthermore, 27 predicted transcription factors (TFs) and 136 predicted motifs were identified. We then selected insulin-like growth factor 1 (IGF1) and its predicted transcription factor, transcription factor A, mitochondrial (TFAM) for further investigation. We speculated and preliminarily confirmed that TFAM may regulate gene transcription of IGF1 and effected alterations in the function recovery of rats after SCI. These findings together provide novel information that may improve our understanding of the pathophysiological processes during the intermediate phase of SCI.

Multiple mechanisms of curcumin targeting spinal cord injury.

Spinal cord injury (SCI) is an irreversible disease process with a high disability and mortality rate. After primary spinal cord injury, the secondary injury may occur in sequence, which is composed of ischemia and hypoxia, excitotoxicity, calcium overload, oxidative stress and inflammation, resulting in massive death of parenchymal cells in the injured area, followed by the formation of syringomyelia. Effectively curbing the process of secondary injury can promote nerve repair and improve functional prognosis. As the main active ingredient in turmeric, curcumin can play an important role in reducing inflammation and oxidation, protecting the neurons, and ultimately reducing spinal cord injury. This article reviews the effects of curcumin on the repair of nerve injury, with emphasis on the various mechanisms by which curcumin promotes the treatment of spinal cord injury.

Programmed cell death in spinal cord injury pathogenesis and therapy.

Spinal cord injury (SCI) always leads to functional deterioration due to a series of processes including cell death. In recent years, programmed cell death (PCD) is considered to be a critical process after SCI, and various forms of PCD were discovered in recent years, including apoptosis, necroptosis, autophagy, ferroptosis, pyroptosis and paraptosis. Unlike necrosis, PCD is known as an active cell death mediated by a cascade of gene expression events, and it is crucial for elimination unnecessary and damaged cells, as well as a defence mechanism. Therefore, it would be meaningful to characterize the roles of PCD to not only enhance our understanding of the pathophysiological processes, but also improve functional recovery after SCI. This review will summarize and explore the most recent advances on how apoptosis, necroptosis, autophagy, ferroptosis, pyroptosis and paraptosis are involved in SCI. This review can help us to understand the various functions of PCD in the pathological processes of SCI, and contribute to our novel understanding of SCI of unknown aetiology in the near future.

Bioinformatic identification of key candidate genes and pathways in axon regeneration after spinal cord injury in zebrafish.

Zebrafish and human genomes are highly homologous; however, despite this genomic similarity, adult zebrafish can achieve neuronal proliferation, regeneration and functional restoration within 6-8 weeks after spinal cord injury, whereas humans cannot. To analyze differentially expressed zebrafish genes between axon-regenerated neurons and axon-non-regenerated neurons after spinal cord injury, and to explore the key genes and pathways of axonal regeneration after spinal cord injury, microarray GSE56842 was analyzed using the online tool, GEO2R, in the Gene Expression Omnibus database. Gene ontology and protein-protein interaction networks were used to analyze the identified differentially expressed genes. Finally, we screened for genes and pathways that may play a role in spinal cord injury repair in zebrafish and mammals. A total of 636 differentially expressed genes were obtained, including 255 up-regulated and 381 down-regulated differentially expressed genes in axon-regenerated neurons. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment results were also obtained. A protein-protein interaction network contained 480 node genes and 1976 node connections. We also obtained the 10 hub genes with the highest correlation and the two modules with the highest score. The results showed that spectrin may promote axonal regeneration after spinal cord injury in zebrafish. Transforming growth factor beta signaling may inhibit repair after spinal cord injury in zebrafish. Focal adhesion or tight junctions may play an important role in the migration and proliferation of some cells, such as Schwann cells or neural progenitor cells, after spinal cord injury in zebrafish. Bioinformatic analysis identified key candidate genes and pathways in axonal regeneration after spinal cord injury in zebrafish, providing targets for treatment of spinal cord injury in mammals.

Epidemiological Features of Spinal Cord Injury in China: A Systematic Review.

Background: Spinal cord injury (SCI) is a severe condition that disrupts patients' physiological, mental, and social well-being state and exerts great financial burden on patients, their families and social healthcare system. This review intends to compile studies regarding epidemiological features of SCI in China. Methods: Searches were conducted on PubMed, EMBASE, Web of Science and Cochrane Library for relevant studies published through January, 2018. Studies reported methodological and epidemiological data were collected by two authors independently. Results: Seventeen studies met the inclusion criteria. Two studies reported incidence of SCI that is 60.6 in Beijing (2002) and 23.7 in Tianjin (2004-2008). All studies showed male had a larger percentage in SCI compared to female except Taiwan (2000-2003). The average male and female ratio was 3-4:1 in China and the highest male and female ratio was 5.74: 1 in Tianjin (2004-2007). Farmers, laborers and unemployed people accounted for more than half of the SCI patients in China. Fall was the primary causation with exception of Heilongjiang (2009-2013), Beijing (2001-2010), and Taiwan (2002-2003), where motor vehicle collision (MCVs) was the leading causation. Pulmonary infection, urinary tract infection and bedsore were common complications, accounting for approximately 70% of SCI patients in China. Conclusion: This review shows that epidemiological features of SCI are various in different regions in China and prevention should be implemented by regions. The number of patients with SCI result from fall and MCVs may become a main public health problem because population aging and economic developing in China. However, because all included studies were retrospective and lacking a register system in China, some data were incomplete and some cases may be left out, so the conclusion may not be generalizable to the other regions.

Aquatic Exercises in the Treatment of Low Back Pain: A Systematic Review of the Literature and Meta-Analysis of Eight Studies.

OBJECTIVE: Low back pain is the most common musculoskeletal condition with a high prevalence. There was no sufficient evidence to recommend that aquatic exercise was potentially beneficial to patients with low back pain. The aim of this study was to systematically analyze all evidence available in the literature about effectiveness of the aquatic exercise. DESIGN: A comprehensive search of PubMed, the Cochrane Library, Embase, and Cumulative Index to Nursing and Allied Health was conducted from their inceptions to November 2016 for randomized controlled trials, which concerned the therapeutic aquatic exercise for low back pain. The results were expressed in terms of standardized mean difference and the corresponding 95% confidence interval. RESULTS: Eight trials involving 331 patients were included in the meta-analysis, and the results showed a relief of pain (standardized mean difference = -0.65, 95% confidence interval = -1.16 to -0.14) and physical function (standardized mean difference = 0.63, 95% confidence interval = 0.17 to 1.09) after aquatic exercise. However, there was no significant effectiveness with regard to general mental health in aquatic group (standardized mean difference = 0.46; 95% confidence interval = -0.22 to 1.15). CONCLUSIONS: Aquatic exercise can statistically significantly reduce pain and increase physical function in patients with low back pain. Further high-quality investigations on a larger scale are required to confirm the results.

Identification of differentially expressed proteins in rats with spinal cord injury during the transitional phase using an iTRAQ-based quantitative analysis.

BACKGROUND: Spinal cord injury (SCI) is a disease associated with high disability and mortality rates. The transitional phase from subacute phase to intermediate phase may play a major role in the process of secondary injury. Changes in protein expression levels have been shown to play key roles in many central nervous system (CNS) diseases. Nevertheless, the roles of proteins in the transitional phase of SCI are not clear. METHODS: We examined protein expression in a rat model 2 weeks after SCI and identified differentially expressed proteins (DEPs) using isobaric tagging for relative and absolute protein quantification (iTRAQ). Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of DEPs were performed. Furthermore, we constructed a protein-protein interaction (PPI) network, and the top 10 high-degree core nodes were identified. Meanwhile, we validated protein level changes of five high-degree core regulated proteins using Western blots. RESULTS: A total of 162 DEPs were identified between the injury group and the control, of which 101 (62.35%) were up-regulated and 61 (37.65%) were down-regulated in the transitional phase of SCI. Key molecular function, cellular components, biological process terms and pathways were identified and may be important mechanisms in the transitional phase of SCI. Alb, Calm1, Vim, Apoe, Syp, P4hb, Cd68, Eef1a2, Rab3a and Lgals3 were the top 10 high-degree core nodes. Western blot analysis performed on five of these proteins showed the same trend as iTRAQ results. CONCLUSION: The current study may provide novel insights into how proteins regulate the pathogenesis of the transitional phase after SCI.

Investigation of candidate long noncoding RNAs and messenger RNAs in the immediate phase of spinal cord injury based on gene expression profiles.

Spinal cord injury (SCI) is a serious devastating condition and it has a high mortality rate and morbidity rate. The early pathological changes in the immediate phase of SCI may play a major part in the development of secondary injury. Alterations in the expression of many long noncoding RNAs (lncRNAs) have been shown to play fundamental roles in the diseases of the central nervous system. However, the roles of lncRNAs and messenger RNAs (mRNAs) in the immediate phase of SCI are not clear. We examined the expression of mRNAs and lncRNAs in a rat model at 2 h after SCI and identified the differentially expressed lncRNAs (DE lncRNAs) and differentially expressed mRNAs (DE mRNAs) using microarray analysis. 772 DE lncRNAs and 992 DE mRNAs were identified in spinal cord samples in the immediate phase following SCI compared with control samples. Moreover, Gene Ontology (GO) term annotation results showed that CXCR chemokine receptor binding, neutrophil apoptotic process, neutrophil migration, neutrophil extravasation, macrophage differentiation, monocyte chemotaxis and cellular response to interleukin-1 (IL-1) were the main significantly enriched GO terms. The results of Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the DEGs were enriched in toll-like receptor signaling pathway, p53 signaling pathway, MAPK signaling pathway and Jak-STAT signaling pathway. IL6, MBOAT4, FOS, TNF, JUN, STAT3, CSF2, MYC, CCL2 and FGF2 were the top 10 high-degree hub nodes and may be important targets in the immediate phase of SCI. The current study on provides novel insights into how lncRNAs and mRNAs regulate the pathogenesis of the immediate phase after SCI.

Exploring the key genes and pathways of osteosarcoma with pulmonary metastasis using a gene expression microarray.

Osteosarcoma is a common and highly malignant tumour in children and teenagers that is characterized by drug resistance and high metastatic potential. Patients often develop pulmonary metastasis and have a low survival rate. However, the mechanistic basis for pulmonary metastasis remains unclear. To identify key gene and pathways associated with pulmonary metastasis of osteosarcoma, the authors downloaded the gene expression dataset GSE85537 and obtained the differentially expressed genes (DEGs) by analyzing high­throughput gene expression in primary tumours and lung metastases. Subsequently, the authors performed gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses and a protein­protein interaction (PPI) network was constructed and analyzed by Cytoscape software. In total, 2,493 genes were identified as DEGs. Of these, 485 genes (19.45%) were upregulated, and the remaining 2,008 genes (80.55%) were downregulated. The authors identified the predominant GO categories and KEGG pathways that were significantly over­represented in the metastatic OS samples compared with the non­metastatic OS samples. A PPI network was constructed, and the results indicated that ALB, EGFR, INS, IL6, CDH1, FYN, ERBB2, IL8, CXCL12 and RAC2 were the top 10 core genes. The enrichment analyses of the genes involved in the top three significant modules demonstrated that the DEGs were principally related to neuroactive ligand­receptor interaction, the Rap1 signaling pathway, and protein digestion and absorption. Together, these data elucidated the molecular mechanisms of OS patients with pulmonary metastasis and provide potential therapeutic targets. However, further experimental studies are needed to confirm these results.

Exploring the key genes and pathways in enchondromas using a gene expression microarray.

Enchondromas are the most common primary benign osseous neoplasms that occur in the medullary bone; they can undergo malignant transformation into chondrosarcoma. However, enchondromas are always undetected in patients, and the molecular mechanism is unclear. To identify key genes and pathways associated with the occurrence and development of enchondromas, we downloaded the gene expression dataset GSE22855 and obtained the differentially expressed genes (DEGs) by analyzing high-throughput gene expression in enchondromas. In total, 635 genes were identified as DEGs. Of these, 225 genes (35.43%) were up-regulated, and the remaining 410 genes (64.57%) were down-regulated. We identified the predominant gene ontology (GO) categories and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways that were significantly over-represented in the enchondromas samples compared with the control samples. Subsequently the top 10 core genes were identified from the protein-protein interaction (PPI) network. The enrichment analyses of the genes mainly involved in two significant modules showed that the DEGs were principally related to ribosomes, protein digestion and absorption, ECM-receptor interaction, focal adhesion, amoebiasis and the PI3K-Akt signaling pathway.Together, these data elucidate the molecular mechanisms underlying the occurrence and development of enchondromas and provide promising candidates for therapeutic intervention and prognostic evaluation. However, further experimental studies are needed to confirm these results.

Long non-coding RNA NONMMUG014387 promotes Schwann cell proliferation after peripheral nerve injury.

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 pHBAd-MCMV-GFP-NONMMUG014387 and pHBAd-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 lncRNA NONMMUG014387 compared with the other two groups. Further, compared with the control group, mRNA and protein levels of Cthrc1, Wnt5a, ROR2, RhoA, 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.