MiR-1224 downregulation inhibits OGD/R-induced hippocampal neuron apoptosis through targeting Ku protein

Transplantation of Neural Stem Cells-Overexpressed Ku70 Improves Neurological Deficits in a Mice Model of Cerebral Ischemia Stroke

Cerebral ischemic stroke is a cerebrovascular disease, which is related to DNA damage. Many researches have shown that Ku70 is a key regulator for DNA damage. Here, we aimed to explore Ku70 roles in cerebral ischemic stroke and its potential molecular mechanism. In our study, neural stem cells (NSCs) were induced by oxygen-glucose deprivation/reoxygenation (OGD/R) for constructing cerebral ischemic stroke cell model. CCK8 assay, Brdu/GFP staining, flow cytometry and TUNEL staining were performed to examine cell proliferation, cell cycle and apoptosis, respectively. Relative mRNA and protein levels were detected by quantitative real-time PCR and western blot analysis, respectively. Ku70 positive cells were examined by immunofluorescence staining. Comet assay was employed to determine DNA damage. Animal experiments were performed to assess the effect of transplanting NSCs and Ku70-overexpressed NSCs on neurological deficits, infarct volume, brain edema and blood‒brain barrier (BBB) integrity in middle cerebral artery occlusion (MCAO) model. Our data found that Ku70 expression was decreased in NSCs after OGD/R. Overexpression of Ku70 reduced DNA damage and apoptosis of OGD/R-induced NSCs. Knockdown of Ku70 promoted the activity of ATM/p53. Moreover, KU60019 (ATM-specific inhibitor) reversed the promoting effects of Ku70 silencing on DNA damage and apoptosis in OGD/R-induced NSCs. In animal experiments, transplantation of NSCs-overexpressed Ku70 enhanced cell survival, improved motor function, reduced infarct volume, relieved brain edema and alleviated BBB dysfunction in MCAO mice models. In conclusion, Ku70 overexpression repressed the DNA damage and apoptosis in OGD/R-induced NSCs by regulating ATM/p53 pathway, and transplantation of NSCs-overexpressed Ku70 played neuroprotective effects in MCAO mice models.

Expression Profiles of Long Noncoding RNAs and Messenger RNAs in a Rat Model of Spinal Cord Injury

Spinal cord injury (SCI) is a serious disorder of the central nervous system with a high disability rate. Long noncoding RNAs (lncRNAs) are reported to mediate many biological processes. The aim of this study was to explore lncRNA and mRNA expression profiles and functional networks after SCI. Differentially expressed genes between SCI model rats and sham controls were identified by microarray assays and analyzed by functional enrichment. Key lncRNAs were identified using a support vector machine- (SVM-) recursive feature elimination (RFE) algorithm. A trans and cis regulation model was used to analyze the regulatory relationships between lncRNAs and their targets. An lncRNA-related ceRNA network was established. We identified 5465 differentially expressed lncRNAs (DE lncRNAs) and 8366 differentially expressed mRNAs (DE mRNAs) in the SCI group compared with the sham group (fold change > 2.0, p < 0.05). Four genes were confirmed by qRT-PCR which were consistent with the microarray data. GSEA analysis showed that most marked changes occurred in pathways related to immune inflammation and nerve cell function, including cytokine-cytokine receptor interaction, neuroactive ligand-receptor interaction, and GABAergic synapse. Enrichment analysis identified 30 signaling pathways, including those associated with immune inflammation response. A total of 40 key lncRNAs were identified using the SVM-RFE algorithm. A key lncRNA-mRNAs coexpression network was generated for 230 951 lncRNA-mRNA pairs with half showing positive correlations. Several key DE lncRNAs were predicted to have "cis"- or "trans"-regulated target genes. The transcription factors, Sp1, JUN, and SOX10, may regulate the interaction between XR_001837123.1 and ETS 1. In addition, five pairs of ceRNA regulatory sequences were constructed. Many mRNAs and lncRNAs were found to be dysregulated after SCI. Bioinformatic analysis showed that DE lncRNAs may play crucial roles in SCI. It is anticipated that these findings will provide new insights into the underlying mechanisms and potential therapeutic targets for SCI.

Bioinformatic analysis of circular RNA expression profiles in a rat lumbosacral spinal root avulsion model

Lumbosacral spinal root avulsion (LSRA) is a severe nerve injury that results in devastating dysfunction in the lower limb. Circular ribonucleic acids (circRNAs) have been reported to be implicated in a variety of diseases. However, the role of circRNAs in LSRA remains unclear. Here, we performed RNA sequencing (RNA-seq) to determine circRNA expression profiles in a rat LSRA model and further investigated their potential functions and the underlying mechanisms by bioinformatic analyses and in vitro experiments. In all, 1708 circRNAs were found to be differentially expressed in spinal cord tissues after LSRA (|fold change| ≥ 2 and p &lt; 0.05), with 591 up-regulated 1117 down-regulated. Meanwhile, 2263 mRNAs were also indentified to be differentially expressed, of which 1471 were upregulated and 792 were downregulated. Eight randomly selected circRNAs and mRNA were successfully verified to be consistent the RNA-seq results by quantitative real-time polymerase chain reaction. Functional analyses based on gene ontology and Kyoto Encyclopedia of Genes and Genomes predicted the potential roles of differentially expressed circRNAs and mRNAs in LSRA, and circRNA/miRNA/mRNA interaction networks revealed that circRNA_7025, a down-regulated circRNA in LSRA, was targeted by two neuronal apoptosis-related miRNAs, rno-miR-1224 and rno-miR-326-5p. Further in vitro experiments revealed that circRNA_7025 protected against oxygen-glucose deprivation induced neuronal apoptosis via the circRNA_7025/miR-1224/miR-326-5p axis. In summary, our results revealed circRNA expression profiles and their potential functions in LSRA. These findings improve our understanding of the pathogenic mechanisms involved in LSRA and might enable us to identify new molecular targets for LSRA.