Background Spinal cord injury (SCI) is a traumatic central nervous system disorder that leads to irreversible neurological dysfunction. Emerging evidence has shown that differentially expressed circular RNAs (circRNAs) after SCI is closely associated with the pathophysiological process. Herein, the potential function of circRNA spermine oxidase (circSmox) in functional recovery after SCI was investigated. Methods Differentiated PC12 cells stimulated with lipopolysaccharide (LPS) were employed as an in vitro model for neurotoxicity research. Levels of genes and proteins were detected by quantitative real‐time PCR and Western blot analysis. Cell viability and apoptosis were determined by CCK‐8 assay and flow cytometry. Western blot analysis was used to detect the protein level of apoptosis‐related markers. The levels of interleukin (IL)‐1β, IL‐6, IL‐8, and tumor necrosis factor (TNF)‐α. Dual‐luciferase reporter, RIP, and pull‐down assays were used to confirm the target relationship between miR‐340‐5p and circSmox or Smurf1 (SMAD Specific E3 Ubiquitin Protein Ligase 1). Results LPS elevated the levels of circSmox and Smurf1, but decreased the levels of miR‐340‐5p in PC12 cells in a dose‐dependent manner. Functionally, circSmox silencing alleviated LPS‐induced apoptosis and inflammation in PC12 cells in vitro. Mechanistically, circSmox directly sponged miR‐340‐5p, which targeted Smurf1. Rescue experiments showed that miR‐340‐5p inhibition attenuated the neuroprotective effect of circSmox siRNA in PC12 cells. Moreover, miR‐340‐5p suppressed LPS‐triggered neurotoxicity in PC12 cells, which was reversed by Smurf1 overexpression. Conclusion CircSmox enhances LPS‐induced apoptosis and inflammation via miR‐340‐5p/Smurf1 axis, providing an exciting view of the potential involvement of circSmox in SCI pathogenesis.

Neuronal loss is the central abnormality occurring in brains suffering from Alzheimer's disease (AD). The notion that AD causes the death of neurons point towards protection of neuronal morphology and function as important therapeutic strategies. The perforant path projections from the entorhinal cortex to the dentate gyrus is the most vulnerable circuit with respect to AD. It's known that the perforant path is a very important structure for synaptic plasticity and cognitive functions. NgR (Nogo receptor) is not only involved in limiting injury-induced axonal growth but also in pathological features of AD. So, the mechanism of how NgR affects the perforant path needs further investigation. In this study, the effect of NgR in the perforant path on the neuronal morphology and function in APP/PS1 transgenic mice was studied. The results showed that downregulation of NgR in perforant path ameliorate the damaged morphology and decreased number of neurons in APP/PS1 mice. Concurrently, NgR knockdown enhanced dendritic complexity and increased postsynaptic protein density in APP/PS1 mice. Furthermore, the RT-PCR results indicated that there is downregulation of M1 phenotypes of microglial gene expression in the hippocampus of TG-shNgR mice. Our study suggests that NgR plays a critical role in microglial phenotype polarization, which might account for the NgR knockdown in the perforant path initiated a decrease in neuronal death and improved synaptic function. Our study provided a better understanding of the perforant path and the role of NgR in AD pathogenesis, thus offering the potential application of hippocampal neurons in treatment of AD.

Background: Gliomas are the most frequent and aggressive cancers in the central nervous system, and spinal cord glioma (SCG) is a rare class of the gliomas. Empty spiracles homobox genes (EMXs) have shown potential tumor suppressing roles in glioma, but the biological function of EMX1 in SCG is unclear. Methods:The EMX1 expression in clinical tissues of patients with SCG was examined. SCG cells were extracted from the tissues, and altered expression of EMX1 was then introduced to examine the role of EMX1 in cell growth and invasiveness in vitro.Xenograft tumors were induced in nude mice for in vivo validation. The targets of EXM1 were predicted via bioinformatic analysis and validated by luciferase and ChIP-qPCR assays. Rescue experiments were conducted to validate the involvements of the downstream molecules.Results: EMX1 was poorly expressed in glioma, which was linked to decreased survival rate of patients according to the bioinformatics prediction. In clinical tissues, EMX1 was poorly expressed in SCG, especially in the high-grade tissues. EMX1 upregulation significantly suppressed growth and metastasis of SCG cells in vitro and in vivo.EMX1 bound to the promoter of WASP family member 2 (WASF2) to suppress its transcription. Restoration of WASF2 blocked the tumor-suppressing effect of EMX1.EMX1 suppressed Wnt/β-catenin signaling activity by inhibiting WASF2. Coronaridine, a Wnt/β-catenin-specific antagonist, blocked SCG cell growth and metastasis induced by WASF2. Conclusion:This study elucidates that EMX1 functions as a tumor inhibitor in SCG by suppressing WASF2-dependent activation of the Wnt/β-catenin axis.