Therapeutic Target For Spinal Cord Injury Research Articles

Secretion of GPNMB from Neural Stem Cells Induced by ET-1 Contributes to Angiogenesis after Spinal Cord Injury.

The feeble plasticity of spinal cord microvascular endothelial cells (SCMECs) after trauma is one of the major causes of spinal cord injury (SCI). Neural stem cells (NSCs) play an important role in nerve repair. Glycoprotein nonmetastatic B (GPNMB) has neuroprotective effects and can be stimulated by endothelin 1 (ET-1), and its expression is upregulated in SCI. Here, we aim to investigate whether elevated ET-1 levels stimulate NSCs to secrete GPNMB, thereby further promoting angiogenesis. Mouse SCMECs and NSCs were isolated, cultured, and identified by flow cytometry and immunofluorescence staining. NSCs were treated with ET-1, while SCMECs were cocultured with NSCs, followed by treatment with ET-1. NCS and SCMEC viability were evaluated using cell counting kit 8 (CCK-8) assay, while cell proliferation, migration, invasion, and angiogenesis were examined using 5'-Ethynyl-2'-Deoxyuridine (EdU) staining, wound healing assay, Transwell assay, and tube formation assay. GPNMB expression in NCSs and SCMECs was quantified by western blot assay, quantitative Real-Time polymerase chain reaction (qRT-PCR), or enzyme-linked immunosorbent assay (ELISA). Mouse SCMECs and NSCs were successfully isolated and cultured. ET-1 promoted NSC viability and proliferation and upregulated GPNMB expression. NSCs and ET-1-treated NSCs promoted the viability, migration, invasion, angiogenesis, and GPNMB expression in SCMECs compared with control group cells, while GPNMB antibody reversed the above effects of ET-1 on the SCMECs. ET-1 promotes SCMEC migration and invasion, along with angiogenesis, by enhancing NSC-mediated GPNMB secretion, so ET-1 may be a novel therapeutic target for SCI.

Identification and bioinformatics analysis of genes associated with pyroptosis in spinal cord injury of rat and mouse

The mechanism of spinal cord injury (SCI) is highly complex, and an increasing number of studies have indicated the involvement of pyroptosis in the physiological and pathological processes of secondary SCI. However, there is limited bioinformatics research on pyroptosis-related genes (PRGs) in SCI. This study aims to identify and validate differentially expressed PRGs in the GEO database, perform bioinformatics analysis, and construct regulatory networks to explore potential regulatory mechanisms and therapeutic targets for SCI. We obtained high-throughput sequencing datasets of SCI in rats and mice from the GEO database. Differential analysis was conducted using the “limma” package in R to identify differentially expressed genes (DEGs). These genes were then intersected with previously reported PRGs, resulting in a set of PRGs in SCI. GO and KEGG enrichment analyses, as well as correlation analysis, were performed on the PRGs in both rat and mouse models of SCI. Additionally, a protein–protein interaction (PPI) network was constructed using the STRING website to examine the relationships between proteins. Hub genes were identified using Cytoscape software, and the intersection of the top 5 hub genes in rats and mice were selected for subsequent experimentally validated. Furthermore, a competing endogenous RNA (ceRNA) network was constructed to explore potential regulatory mechanisms. The gene expression profiles of GSE93249, GSE133093, GSE138637, GSE174549, GSE45376, GSE171441_3d and GSE171441_35d were selected in this study. We identified 10 and 12 PRGs in rats and mice datasets respectively. Six common DEGs were identified in the intersection of rats and mice PRGs. Enrichment analysis of these DEGs indicated that GO analysis was mainly focused on inflammation-related factors, while KEGG analysis showed that the most genes were enriched on the NOD-like receptor signaling pathway. We constructed a ceRNA regulatory network that consisted of five important PRGs, as well as 24 miRNAs and 34 lncRNAs. This network revealed potential regulatory mechanisms. Additionally, the three hub genes obtained from the intersection were validated in the rat model, showing high expression of PRGs in SCI. Pyroptosis is involved in secondary SCI and may play a significant role in its pathogenesis. The regulatory mechanisms associated with pyroptosis deserve further in-depth research.

Identification and Validation of Ferroptosis-Related Genes in Patients with Acute Spinal Cord Injury.

Ferroptosis plays crucial roles in the pathology of spinal cord injury (SCI). The purpose of this study was to identify differentially expressed ferroptosis-related genes (DE-FRGs) in human acute SCI by bioinformatics analysis and validate the hub DE-FRGs in non-SCI and SCI patients. The GSE151371 dataset was downloaded from the Gene Expression Omnibus and difference analysis was performed. The differentially expressed genes (DEGs) in GSE151371 overlapped with the ferroptosis-related genes (FRGs) obtained from the Ferroptosis Database. A total of 41 DE-FRGs were detected in 38 SCI samples and 10 healthy samples in GSE151371. Then, enrichment analyses of these DE-FRGs were performed for functional annotation. The GO enrichment results showed that upregulated DE-FRGs were mainly associated with reactive oxygen species and redox reactions, and the KEGG enrichment analysis indicated involvement in some diseases and ferroptosis pathways. Protein-protein interaction (PPI) analysis and lncRNA-miRNA-mRNA regulatory network were performed to explore the correlations between genes and regulatory mechanisms. The relationship between DE-FRGs and differentially expressed mitochondria-related genes (DE-MRGs) was also analyzed. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the hub DE-FRGs in clinical blood samples from acute SCI patients and healthy controls. Consistent with the bioinformatics results, qRT-PCR of the clinical samples indicated similar expression levels of TLR4, STAT3, and HMOX1. This study identified DE-FRGs in blood samples from SCI patients, and the results could improve our understanding of the molecular mechanisms of ferroptosis in SCI. These candidate genes and pathways could be therapeutic targets for SCI.

Eucommia ulmoides extract alleviated spinal cord injury in rats by inhibiting endoplasmic reticulum stress and oxidative stress

Spinal cord injury (SCI) is the major cause of severe disability worldwide, which leads to neuron death, neuronal degeneration, and functional changes in the spinal cord. Eucommia ulmoides extract (EUE) is composed of multiple iridoids and phenols and possesses anti-oxidative and anti-inflammatory effects in various pathologies. This study aims to evaluate the effects of EUE on SCI and the underlying mechanisms. Male adult Sprague-Dawley rats (250–280 g) were applied to mimic SCI in vivo. Western blot and ELISA kits assessed the expressions of apoptosis, oxidative stress, and endoplasmic reticulum stress (ER stress)-relevant proteins. The apoptosis rate of neurons in spinal cord specimens was measured by TUNEL assay. Finally, our data indicated that EUE inhibited SCI-induced apoptosis, oxidative stress, and ER stress through the suppression of mitogen-activated protein kinase (MAPK) pathway. Our data manifest EUE as a potential therapeutic target in SCI.

Inhibition of IL1R1 or CASP4 attenuates spinal cord injury through ameliorating NLRP3 inflammasome-induced pyroptosis.

Spinal cord injury (SCI) is a devastating trauma characterized by serious neuroinflammation and permanent neurological dysfunction. However, the molecular mechanism of SCI remains unclear, and few effective medical therapies are available at present. In this study, multiple bioinformatics methods were used to screen out novel targets for SCI, and the mechanism of these candidates during the progression of neuroinflammation as well as the therapeutic effects were both verified in a rat model of traumatic SCI. As a result, CASP4, IGSF6 and IL1R1 were identified as the potential diagnostic and therapeutic targets for SCI by computational analysis, which were enriched in NF-κB and IL6-JAK-STATA3 signaling pathways. In the injured spinal cord, these three signatures were up-regulated and closely correlated with NLRP3 inflammasome formation and gasdermin D (GSDMD) -induced pyroptosis. Intrathecal injection of inhibitors of IL1R1 or CASP4 improved the functional recovery of SCI rats and decreased the expression of these targets and inflammasome component proteins, such as NLRP3 and GSDMD. This treatment also inhibited the pp65 activation into the nucleus and apoptosis progression. In conclusion, our findings of the three targets shed new light on the pathogenesis of SCI, and the use of immunosuppressive agents targeting these proteins exerted anti-inflammatory effects against spinal cord inflammation by inhibiting NF-kB and NLRP3 inflammasome activation, thus blocking GSDMD -induced pyroptosis and immune activation.

Synaptic Cell Adhesion Molecule 3 (SynCAM3) Deletion Promotes Recovery from Spinal Cord Injury by Limiting Glial Scar Formation.

Synaptic cell adhesion molecules (SynCAMs) play an important role in the formation and maintenance of synapses and the regulation of synaptic plasticity. SynCAM3 is expressed in the synaptic cleft of the central nervous system (CNS) and is involved in the connection between axons and astrocytes. We hypothesized that SynCAM3 may be related to the astrocytic scar (glial scar, the most important factor of CNS injury treatment) through extracellular matrix (ECM) reconstitution. Thus, we investigated the influence of the selective removal of SynCAM3 on the outcomes of spinal cord injury (SCI). SynCAM3 knock-out (KO) mice were subjected to moderate compression injury of the lower thoracic spinal cord using wild-type (WT) (C57BL/6JJc1) mice as controls. Single-cell RNA sequencing analysis over time, quantitative real-time polymerase chain reaction (qRT-PCR) analysis, and immunohistochemistry (IHC) showed reduced scar formation in SynCAM3 KO mice compared to WT mice. SynCAM3 KO mice showed improved functional recovery from SCI by preventing the transformation of reactive astrocytes into scar-forming astrocytes, resulting in improved ECM reconstitution at four weeks after injury. Our findings suggest that SynCAM3 could be a novel therapeutic target for SCI.

MiR-181a-5p Alleviates the Inflammatory Response of PC12 Cells by Inhibiting High-Mobility Group Box-1 Protein Expression

Neuroinflammation triggers sequelae after spinal cord injury (SCI). Inhibition of inflammation promotes recovery after SCI. MicroRNAs regulate many pathophysiological processes, including inflammation. Any role for miR-181a-5p in the inflammatory response after SCI remains unclear. Thus, we evaluated the effects of miR-181a-5p on inflammation in PC12cells and the underlying mechanism in play. Quantitative reverse transcription-polymerase chain reaction was used to measure the levels of miR-181a-5p and high-mobility group box-1 protein (HMGB1) in SCI tissues. Cell-counting kit-8 assays were used to assess the viability of PC12cells treated with lipopolysaccharide (LPS). Plasmids encoding MiR-181a-5p mimics, an miR-181a-5p inhibitor, or/and the HMGB1 weretransfected into PC12cells. Quantitative reverse transcription-polymerase chain reaction or/and Western blotting were performed to assess the expression of miR-181a-5p, HMGB1, and inflammatory factors invitro. MiR-181a-5p expression decreased and HMGB1 expression increased in SCI tissues and LPS-induced PC12cells. Upregulation of miR-181a-5p (via transfection) inhibited inflammation of, and HMGB1 expression by, LPS-induced PC12cells. HMGB1 overexpression reversed the anti-inflammatory effects of miR-181a-5p. Dual-luciferase assays confirmed that HMGB1 was a direct target of miR-181a-5p. miR-181a-5p attenuated the inflammatory response of LPS-induced PC12cells by directly inhibiting HMGB1; thus, miR-181a-5p may serve as a therapeutic target in SCI.

Hematogenous Macrophages: A New Therapeutic Target for Spinal Cord Injury.

Spinal cord injury (SCI) is a devastating disease leading to loss of sensory and motor functions, whose pathological process includes mechanical primary injury and secondary injury. Macrophages play an important role in SCI pathology. According to its origin, it can be divided into resident microglia and peripheral monocyte-derived macrophages (hematogenous Mφ). And it can also be divided into M1-type macrophages and M2-type macrophages on the basis of its functional characteristics. Hematogenous macrophages may contribute to the SCI process through infiltrating, scar forming, phagocytizing debris, and inducing inflammatory response. Although some of the activities of hematogenous macrophages are shown to be beneficial, the role of hematogenous macrophages in SCI remains controversial. In this review, following a brief introduction of hematogenous macrophages, we mainly focus on the function and the controversial role of hematogenous macrophages in SCI, and we propose that hematogenous macrophages may be a new therapeutic target for SCI.

Stat3-Induced lncRNA Kcnq1ot1 Regulates the Apoptosis of Neuronal Cells in Spinal Cord Injury.

Emerging evidence validates the vital roles of long noncoding RNAs (lncRNAs) in spinal cord injury (SCI), which attracts great attention. In the present study, our study investigated the function and in-depth mechanism of lncRNA Kcnq1 overlapping transcript 1 (Kcnq1ot1) in SCI. Results indicated that lncRNA Kcnq1ot1 expression upregulated in the hypoxia-administered neuronal cells (PC12 cells) and SCI rat models. Moreover, transcription factor signal transducer and activator of transcription 3 (Stat3) accelerated the transcriptional enrichment of Kcnq1ot1 in SCI cellular model. Functional experiments demonstrated that Kcnq1ot1 knockdown repressed the apoptosis of neuronal cells. Mechanistically, Kcnq1ot1 recruited EZH2 to the promoter region of p27 to repress its transcription. Taken together, our results indicate that Stat3-induced lncRNA Kcnq1ot1 regulates the apoptosis in SCI through epigenetically silencing p27, contributing to novel therapeutic target for SCI.

RETRACTED ARTICLE: Inhibition of TGF-β repairs spinal cord injury by attenuating EphrinB2 expressing through inducing miR-484 from fibroblast

Spinal cord injury (SCI) can lead to severe loss of motor and sensory function with high disability and mortality. The effective treatment of SCI remains unknown. Here we find systemic injection of TGF-β neutralizing antibody induces the protection of axon growth, survival of neurons, and functional recovery, whereas erythropoietin-producing hepatoma interactor B2 (EphrinB2) expression and fibroblasts distribution are attenuated. Knockout of TGF-β type II receptor in fibroblasts can also decrease EphrinB2 expression and improve spinal cord injury recovery. Moreover, miR-488 was confirmed to be the most upregulated gene related to EphrinB2 releasing in fibroblasts after SCI and miR-488 initiates EphrinB2 expression and physical barrier building through MAPK signaling after SCI. Our study points toward elevated levels of active TGF-β as inducer and promoters of fibroblasts distribution, fibrotic scar formation, and EphrinB2 expression, and deletion of global TGF-β or the receptor of TGF-β in Col1α2 lineage fibroblasts significantly improve functional recovery after SCI, which suggest that TGF-β might be a therapeutic target in SCI.

Identification of Key eRNAs for Spinal Cord Injury by Integrated Multinomial Bioinformatics Analysis.

Background: Spinal cord injury (SCI) is a severe neurological deficit affecting both young and older people worldwide. The potential role of key enhancer RNAs (eRNAs) in SCI remains elusive, which is a prominent challenge in the trauma repair process. This study aims to investigate the roles of key eRNAs, transcription factors (TFs), signaling pathways, and small-molecule inhibitors in SCI using multi-omics bioinformatics analysis.Methods: Microarray data of peripheral blood mononuclear cell (PBMC) samples from 27 healthy volunteers and 25 chronic-phase SCI patients were retrieved from the Gene Expression Omnibus database. Differentially expressed transcription factors (DETFs), differentially expressed enhancer RNAs (DEeRNAs), and differentially expressed target genes (DETGs) were identified using the Linear Models for Microarray Data (limma) package. Fraction of immune cells was estimated using CIBERSORT algorithm. Gene Set Variation Analysis (GSVA) was applied to identify the downstream signaling pathways. The eRNA regulatory network was constructed based on the correlation results. Connectivity Map (CMap) database was used to find potential drugs for SCI patients. The cellular communication analysis was performed to explore the molecular regulation mechanism of SCI based on single-cell RNA sequencing (scRNA-seq) data. Chromatin immunoprecipitation sequencing (ChIP-seq) and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) data were used to validate the key regulatory mechanisms. scRNA-seq dataset was used to validate the cell subtype localization of the key eRNAs.Results: In total, 21 DETFs, 24 DEeRNAs, and 829 DETGs were identified. A regulatory network of 13 DETFs, six DEeRNAs, seven DETGs, two hallmark pathways, two immune cells, and six immune pathways was constructed. The link of Splicing factor proline and glutamine rich (SFPQ) (TF) and vesicular overexpressed in cancer prosurvival protein 1 (VOPP1) (eRNA) (R = 0.990, p < 0.001, positive), VOPP1 (eRNA) and epidermal growth factor receptor (EGFR) (target gene) (R = 0.974, p < 0.001, positive), VOPP1, and T helper (Th) cells (R = −0.987, p < 0.001, negative), and VOPP1 and hallmark coagulation (R = 0.937, p < 0.001, positive) was selected. Trichostatin A was considered the best compound target to SCI-related eRNAs (specificity = 0.471, p < 0.001).Conclusion: VOPP1, upregulated by SFPQ, strengthened the transient expression of EGFR. Th cells and coagulation were the potential downstream pathways of VOPP1. This regulatory network and potential inhibitors provide novel diagnostic biomarkers and therapeutic targets for SCI.

MicroRNA-182 improves spinal cord injury in mice by modulating apoptosis and the inflammatory response via IKKβ/NF-κB

Spinal cord injury (SCI) is one common neurological condition which involves primary injury and secondary injury. Neuron inflammation and apoptosis after SCI is the most important pathological process of this disease. Here, we tried to explore the influence and mechanism of miRNAs on the neuron inflammatory response and apoptosis after SCI. First, by re-analysis of Gene Expression Omnibus dataset (accession GSE19890), miR-182 was selected for further study because of its suppressive effects on the inflammatory response in the various types of injuries. Functional experiments demonstrated that miR-182 overexpression promoted functional recovery, reduced histopathological changes, and alleviated spinal cord edema in mice. It was also observed that miR-182 overexpression reduced apoptosis and attenuated the inflammatory response in spinal cord tissue, as evidenced by the reduction of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β, and the induction of IL-10. Using a lipopolysaccharide (LPS)-induced SCI model in BV-2 cells, we found that miR-182 was downregulated in the BV-2 cells following LPS stimulation, and upregulation of miR-182 improved LPS-induced cell damage, as reflected by the inhibition of apoptosis and the inflammatory response. IκB kinase β (IKKβ), an upstream target of the NF-κB pathway, was directly targeted by miR-182 and miR-182 suppressed its translation. Further experiments revealed that overexpression of IKKβ reversed the anti-apoptosis and anti-inflammatory effects of miR-182 in LPS stimulated BV-2 cells. Finally, we found that miR-182 overexpression blocked the activation of the NF-κB signaling pathway in vitro and in vivo, as demonstrated by the downregulation of phosphorylated (p‑) IκB-α and nuclear p-p65. Taken together, these data indicate that miR-182 improved SCI-induced secondary injury through inhibiting apoptosis and the inflammatory response by blocking the IKKβ/NF-κB pathway. Our findings suggest that upregulation of miR-182 may be a novel therapeutic target for SCI.overexpression of the microRNA miR-182 promotes functional recovery and reduced histopathological changes in spinal cord injury mice. miR-182 overexpression reduces apoptosis and attenuates the inflammatory response in spinal cord tissues by blocking the IKKβ/NF-κB pathway. These findings suggest that upregulation of miR-182 may be a novel therapeutic target for SCI.

Inhibition of ERK1/2 phosphorylation attenuates spinal cord injury induced astrocyte activation and inflammation through negatively regulating aquaporin-4 in rats

The extracellular signal-regulated kinase (ERK) pathway has been reported to play a pivotal role in mediating spinal cord injury (SCI) progression. The present study aimed to investigate the effects of phosphorylated ERK1/2 (p-ERK1/2) inhibition on SCI-induced astrocyte activation and inflammation and its possible mechanism in rats. Here, female Sprague-Dawley rats were randomly assigned to four groups: (1) Sham group, (2) SCI group, (3) TGN-020 group (aquaporin-4, AQP4, blocking agent), (4) PD98059 group (ERK blocking agent). A well SCI model was established by compressing the thoracic vertebra 10 level (weight 35 g, time 5 min) in rats. Western blotting and immunofluorescence staining were used to measure the expression of associated proteins after SCI. HE staining and Nissl staining were performed to detect the morphological changes of spinal cords and the number of surviving neurons following SCI, respectively. The Basso-Beattie-Bresnahan open-field rating scale was used to evaluate functional locomotor recovery following SCI in rats. Our results demonstrated that SCI significantly induced the upregulation of aquaporin-4, p-ERK1/2, glial fibrillary acidic protein, proliferating cell nuclear antigen, and proinflammatory cytokines (tumor necrosis factor-α, interleukin-6 and interleukin-1β). However, treatment with TGN-020 or PD98059 could effectively inhibit astrocyte proliferation and proinflammatory cytokine release, preserve the number of surviving ventral horn neurons, and subsequently improve the locomotor function of rats after SCI. Interestingly, the SCI-induced elevation of AQP4 expression was downregulated by p-ERK1/2 inhibition, suggesting that blocking ERK1/2 phosphorylation could attenuate astrocyte activation and inflammatory processes through negative regulation of AQP4. Therefore, p-ERK1/2 blockade may be employed as a therapeutic target for SCI.

Macrophage migration inhibitory factor as a therapeutic target after traumatic spinal cord injury: a systematic review.

Macrophages play an important role in mediating damage after Spinal cord injury (SCI) by secreting macrophage migration inhibitory factor (MMIF) as a secondary injury mediator. We aimed to systematically review the role of MMIF as a therapeutic target after traumatic SCI. Our systematic review has been performed according to the PRISMA 2009 Checklist. A systematic search in the scientific databases was carried out for studies published before 20 February 2019 from major databases. Two researchers independently screened titles. The risk of bias of eligible articles was assessed, and data were extracted. Finally, we systematically analyzed and interpreted related data. 785 papers were selected for the title and abstract screening. 12 papers were included for data extraction. Eight animal studies were of high quality and the remaining two were of medium quality. One of the two human studies was of poor quality and the other was of fair quality. MMIF as a pro-inflammatory mediator can cause increased susceptibility to glutamate-related neurotoxicity, increased nitrite production, increased ERK activation, and increased COX2/PGE2 signaling pathway activation and subsequent stimulation of CCL5-related chemotaxis. Two human studies and six animal studies demonstrated that MMIF level increases after SCI. MMIF inhibition might be a potential therapeutic target in SCI by multiple different mechanisms (6/12 studies). Most animal studies demonstrate significant neurologic improvement after administration of MMIF inhibitors, but these inhibitors have not been studied in humans yet. Further clinical trials are need to further understand MMIF inhibitor utility in acute or chronic SCI. Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Integrated Bioinformatics Analysis of Hub Genes and Pathways Associated with a Compression Model of Spinal Cord Injury in Rats.

BackgroundSpinal cord injury (SCI) is a serious nervous system condition that can cause lifelong disability. The aim of this study was to identify potential molecular mechanisms and therapeutic targets for SCI.Material/MethodsWe constructed a weighted gene coexpression network and predicted which hub genes are involved in SCI. A compression model of SCI was established in 45 Sprague-Dawley rats, which were divided into 5 groups (n=9 per group): a sham operation group, and 1, 3, 5, and 7 days post-SCI groups. The spinal cord tissue on the injured site was harvested on 1, 3, 5, and 7 days after SCI and 3 days after surgery in the sham operation group. High-throughput sequencing was applied to investigate the expression profile of the mRNA in all samples. Differentially expressed genes were screened and included in weighted gene coexpression network analysis (WGCNA). Co-expressed modules and hub genes were identified by WGCNA. The biological functions of each module were investigated using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases.ResultsAccording to the RNA-seq data, a total of 1965 differentially expressed genes were screened, and WGCNA identified 10 coexpression modules and 5 hub genes. Module function analysis revealed that SCI was associated with immune response, cell division, neuron projection development, and collagen fibril organization.ConclusionsOur study revealed dynamic changes in a variety of biological processes following SCI and identified 5 hub genes via WGCNA. These results provide insights into the molecular mechanisms and therapeutic targets of SCI.

Elevating sestrin2 attenuates endoplasmic reticulum stress and improves functional recovery through autophagy activation after spinal cord injury

Spinal cord injury (SCI) is a devastating neurological trauma that causes losses of motor and sensory function. Sestrin2, also known as hypoxia inducible gene 95, is emerging as a critical determinant of cell homeostasis in response to cellular stress. However, the role of sestrin2 in the neuronal response to endoplasmic reticulum (ER) stress and the potential mechanism remain undefined. In this study, we investigated the effects of sestrin2 on ER stress and delineated an underlying molecular mechanism after SCI. Here, we found that elevated sestrin2 is a protective process in neurons against chemical ER stress induced by tunicamycin (TM) or traumatic invasion, while treatment with PERK inhibitor or knockdown of ATF4 reduces sestrin2 expression upon ER stress. In addition, we demonstrated that overexpression of sestrin2 limits ER stress, promoting neuronal survival and improving functional recovery after SCI, which is associated with activation of autophagy and restoration of autophagic flux mediated by sestrin2. Moreover, we also found that sestrin2 activates autophagy dependent on the AMPK-mTOR signaling pathway. Consistently, inhibition of AMPK abrogates the effect of sestrin2 on the activation of autophagy, and blockage of autophagic flux abolishes the effect of sestrin2 on limiting ER stress and neural death. Together, our data reveal that upregulation of sestrin2 is an important resistance mechanism of neurons to ER stress and the potential role of sestrin2 as a therapeutic target for SCI. Graphical abstract.

MicroRNA-129-5p alleviates spinal cord injury in mice via suppressing the apoptosis and inflammatory response through HMGB1/TLR4/NF-κB pathway.

Secondary injury after spinal cord injury (SCI) is one reversible pathological change mainly involving excessive inflammatory response and neuro-apoptosis. Since in recent years, microRNAs (miRNAs) have been proposed as novel regulators of inflammation in different disease conditions. However, the role of miRNAs in the inflammatory response and apoptosis of secondary injury after SCI remains to be fully elucidated. Here, we tried to explore the influence and mechanism of miRNAs on the neuron inflammatory response and apoptosis after SCI. The expression profiles of miRNA were examined using miRNA microarray, and among the candidate miRNAs, miR-129-5p was found to be the most down-regulated miRNA in spinal tissues. Overexpression of miR-129-5p using agomir-miR-129-5p promoted injury mice functional recovery, suppressed the apoptosis and alleviated inflammatory response in spinal tissues. Using LPS-induced BV-2 cell model, we found miR-129-5p was also proved in protecting inflammatory response and cell apoptosis in vitro. High-mobility group protein B1 (HMGB1), a well-known inflammatory mediator, was found to be directly targeted by miR-129-5p and it was associated with the inhibitory effect of miR-129-5p on the activation of toll-like receptor (TLR)-4 (TLR4)/ nuclear factor-κB (NF-κB) pathway in vitro and in vivo. Further experiments revealed that the anti-apoptosis and anti-inflammatory effects of miR-129-5p were reversed by HMGB1 overexpression in BV-2 cells. Collectively, these data revealed that miR-129-5p alleviated SCI in mice via suppressing the apoptosis and inflammatory response through HMGB1//TLR4/NF-κB pathway. Our data suggest that up-regulation of miR-129-5p may be a novel therapeutic target for SCI.

Differential Expression Profiles and Functional Prediction of tRNA-Derived Small RNAs in Rats After Traumatic Spinal Cord Injury

Spinal cord injury (SCI) is mostly caused by trauma. As the primary mechanical injury is unavoidable, a focus on the underlying molecular mechanisms of the SCI-induced secondary injury is necessary to develop promising treatments for patients with SCI. Transfer RNA-derived small RNA (tsRNA) is a novel class of short, non-coding RNA, possessing potential regulatory functions in various diseases. However, the functional roles of tsRNAs in traumatic SCI have not been determined yet. We used a combination of sequencing, quantitative reverse transcription-polymerase chain reaction (qRT-PCR), bioinformatics, and luciferase reporter assay to screen the expression profiles and identify the functional roles of tsRNAs after SCI. As a result, 297 differentially expressed tsRNAs were identified in rats’ spinal cord 1 day after contusion. Of those, 155 tsRNAs were significantly differentially expressed: 91 were significantly up-regulated, whereas 64 were significantly down-regulated after SCI (fold change > 1.5; P < 0.05). Bioinformatics analyses revealed candidate tsRNAs (tiRNA-Gly-GCC-001, tRF-Gly-GCC-012, tRF-Gly-GCC-013, and tRF-Gly-GCC-016) that might play regulatory roles through the mitogen-activated protein kinase (MAPK) and neurotrophin signaling pathways by targeting brain-derived neurotrophic factor (BDNF). We validated the candidate tsRNAs and found opposite trends in the expression levels of the tsRNAs and BDNF after SCI. Finally, tiRNA-Gly-GCC-001 was identified to target BDNF using the luciferase reporter assay. In summary, we found an altered tsRNA expression pattern and predicted tiRNA-Gly-GCC-001 might be involved in the MAPK and neurotrophin pathways by targeting the BDNF, thus regulating the post-SCI pathophysiologic processes. This study provides novel insights for future investigations to explore the mechanisms and therapeutic targets for SCI.

Construction of the gene network in the spinal cord injury treated by coptidis rhizoma based on network pharmacological and molecular docking

ObjectiveTo explore the potential molecular network mechanism of coptidis rhizoma in the treatment of spinal cord injury (SCI) based on network pharmacology and molecular docking technology.MethodsThe compounds of coptidis rhizoma and therapeutic targets for SCI were predicted and screened from TCMSP. Genes related to SCI were searched in GeneCards. Protein‐protein interaction (PPI) network was constructed and the key targets were screened. The drug‐component‐target‐pathway network was constructed. AutoDock software was used for molecular docking verification.ResultsFourteen compounds were screened from coptidis rhizoma, consisting of 148 potential targets, 133 of which were related to SCI. Interleukin‐6 (IL‐6), cysteine aspartate protease 3 (Casp3), proto‐oncogene protein c‐Jun (Jun), cyclooxygenase 2 (Ptgs2), and proto‐oncogene protein c‐Myc (Myc) were constructed as an interaction network. The biological processes involved in the treatment of SCI by coptidis rhizoma mainly include adenylate cyclase‐inhibiting G protein‐coupled acetylcholine receptor signaling pathway, etc. The results of molecular docking showed that the main active components in Coptis chinensis had a stable binding activity with the core target.ConclusionThe treatment of SCI by coptidis rhizoma involves multiple targets, to promote neuronal survival, inhibit nerve cells apoptosis, in the process of SCI, which is useful to understand the mechanism of coptidis rhizoma for the treatment of SCI in future clinical applications.

Astragoloside IV Loaded Polycaprolactone Membrane Repairs Blood Spinal Cord Barrier and Recovers Spinal Cord Function in Traumatic Spinal Cord Injury.

Traumatic Spinal Cord Injury (SCI) is a serious challenge of CNS which may oftenly result in permanent paralysis and disability. The disruption of blood spinal cord barrier (BSCB) is a major step in the secondary injury of SCI. Until recently there are no restorative therapies for traumatic SCI. BSCB is considered to be a therapeutic target for SCI, however few biomaterials have been developed to restore the disrupted BSCB in SCI. In this study, an AST-PCL membrane was fabricated with a steady release of Astragoloside IV (AST) and its effects on BSCB repair as well as the functional recovery of SCI were evaluated. Firstly, this study demonstrated that AST-PCL (polycaprolactone) degradation media protects endothelial cells from apoptosis by down-regulating the expression of cleaved Caspase 3 and decreasing the ratio of Bax/Bcl-2, it also attenuates the stress fiber formation in vitro. Secondly, the rat model of traumatic SCI showed that AST-PCL treatment inhibits the disruption of BSCB permeability, as detected by MRI, Evan's Blue extravasation and water content. Thirdly, this study found that AST-PCL up-regulates the level of tight junction proteins including Occludin, Claudin5 and ZO-1. Furthermore, it is also demonstrated that AST-PCL treatment down-regulates Matrix metalloproteinase-9 secretion and diminishes neutrophil infiltration. Finally, this study found that AST-PCL treatment could significantly inhibit apoptosis, decrease tissue damage and improve functional recovery in SCI rats. Taken together, this study shows that AST-PCL might be an efficient biomaterial for BSCB repair and a potential drug therapy for SCI.