Vimentin as a potential target for diverse nervous system diseases

Vimentin is a major type Ⅲ intermediate filament protein that plays important roles in several basic cellular functions including cell migration, proliferation, and division. Although vimentin is a cytoplasmic protein, it also exists in the extracellular matrix and at the cell surface. Previous studies have shown that vimentin may exert multiple physiological effects in different nervous system injuries and diseases. For example, the studies of vimentin in spinal cord injury and stroke mainly focus on the formation of reactive astrocytes. Reduced glial scar, increased axonal regeneration, and improved motor function have been noted after spinal cord injury in vimentin and glial fibrillary acidic protein knockout(GFAPVIM) mice. However, attenuated glial scar formation in post-stroke in GFAP–/– VIM–/– mice resulted in abnormal neuronal network restoration and worse neurological recovery. These opposite results have been attributed to the multiple roles of glial scar in different temporal and spatial conditions. In addition, extracellular vimentin may be a neurotrophic factor that promotes axonal extension by interaction with the insulin-like growth factor 1 receptor. In the pathogenesis of bacterial meningitis, cell surface vimentin is a meningitis facilitator, acting as a receptor of multiple pathogenic bacteria, including E. coli K1, Listeria monocytogenes, and group B streptococcus. Compared with wild type mice, VIMmice are less susceptible to bacterial infection and exhibit a reduced inflammatory response, suggesting that vimentin is necessary to induce the pathogenesis of meningitis. Recently published literature showed that vimentin serves as a double-edged sword in the nervous system, regulating axonal regrowth, myelination, apoptosis, and neuroinflammation. This review aims to provide an overview of vimentin in spinal cord injury, stroke, bacterial meningitis, gliomas, and peripheral nerve injury and to discuss the potential therapeutic methods involving vimentin manipulation in improving axonal regeneration, alleviating infection, inhibiting brain tumor progression, and enhancing nerve myelination.

Expression of long non-coding RNAs in complete transection spinal cord injury: a transcriptomic analysis

Long non-coding RNAs(lncRNAs)are abundantly expressed in the central nervous system and exert a critical role in gene regulation via multiple biological processes.To uncover the functional significance and molecular mechanisms of lncRNAs in spinal cord injury(SCI),the expression signatures of lncRNAs were profiled using RNA sequencing(RNA-seq)technology in a Sprague-Dawley rat model of the 10th thoracic vertebra complete transection SCI.Results showed that 116 of 14,802 detected lncRNAs were differentially expressed,among which 16—including eight up-regulated(H19,Vof16,Hmox2-ps1,LOC100910973,Ybx1-ps3,Nnat,Gcgr,LOC680254)and eight down-regulated(Rmrp,Terc,Ngrn,Ppp2r2b,Cox6a2,Rpl37a-ps1,LOC360231,Rpph1)—demonstrated fold changes>2 in response to transection SCI.A subset of these RNA-seq results was validated by quantitative real-time PCR.The levels of 821 mRNAs were also significantly altered post-SCI;592 mRNAs were up-regulated and 229 mRNAs were down-regulated by more than 2-fold.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)analyses showed that differentially expressed mRNAs were related to GO biological processes and molecular functions such as injury and inflammation response,wound repair,and apoptosis,and were significantly enriched in 15 KEGG pathways,including cell phagocytosis,tumor necrosis factor alpha pathway,and leukocyte migration.Our results reveal the expression profiles of lncRNAs and mRNAs in the rat spinal cord of a complete transection model,and these differentially expressed lncRNAs and mRNAs represent potential novel targets for SCI treatment.We suggest that lncRNAs may play an important role in the early immuno-inflammatory response after spinal cord injury.This study was approved by the Administration Committee of Experimental Animals,Guangdong Province,China.

Effect of lentiviral vector-mediated overexpression of hypoxia-inducible factor 1 alpha delivered by pluronic F-127 hydrogel on brachial plexus avulsion in rats

Brachial plexus avulsion often results in massive motor neuron death and severe functional deficits of target muscles. However, no satisfactory treatment is currently available. Hypoxia-inducible factor 1α is a critical molecule targeting several genes associated with ischemia-hypoxia damage and angiogenesis. In this study, a rat model of brachial plexus avulsion-reimplantation was established, in which C5–7 ventral nerve roots were avulsed and only the C6 root reimplanted. Different implants were immediately injected using a microsyringe into the avulsion-reimplantation site of the C6 root post-brachial plexus avulsion. Rats were randomly divided into five groups: phosphate-buffered saline, negative control of lentivirus, hypoxia-inducible factor 1α(hypoxia-inducible factor 1α overexpression lentivirus), gel(pluronic F-127 hydrogel), and gel + hypoxia-inducible factor 1α(pluronic F-127 hydrogel + hypoxia-inducible factor 1α overexpression lentivirus). The Terzis grooming test was performed to assess recovery of motor function. Scores were higher in the hypoxia-inducible factor 1α and gel +hypoxia-inducible factor 1α groups(in particular the gel + hypoxia-inducible factor 1α group) compared with the phosphate-buffered saline group. Electrophysiology, fluorogold retrograde tracing, and immunofluorescent staining were further performed to investigate neural pathway reconstruction and changes of neurons, motor endplates, and angiogenesis. Compared with the phosphate-buffered saline group, action potential latency of musculocutaneous nerves was markedly shortened in the hypoxia-inducible factor 1α and gel + hypoxia-inducible factor1α groups. Meanwhile, the number of fluorogold-positive cells and ChAT-positive neurons, neovascular area(labeled by CD31 around av ulsed sites in ipsilateral spinal cord segments), and the number of motor endplates in biceps brachii(identified by α-bungarotoxin) were all visibly increased, as well as the morphology of motor endplate in biceps brachil was clear in the hypoxia-inducible factor 1α and gel + hypoxia-inducible factor 1α groups. Taken together, delivery of hypoxia-inducible factor 1α overexpression lentiviral vectors mediated by pluronic F-127 effectively promotes spinal root regeneration and functional recovery post-brachial plexus avulsion. All animal procedures were approved by the Institutional Animal Care and Use Committee of Guangdong Medical University, China.

Inhibition of LncRNA Vof-16 expression promotes nerve regeneration and functional recovery after spinal cord injury

Our previous RNA sequencing study showed that the long non-coding RNA ischemia-related factor Vof-16(lncRNA Vof-16)was upregulated after spinal cord injury,but its precise role in spinal cord injury remains unclear.Bioinformatics predictions have indicated that lncRNA Vof-16 may participate in the pathophysiological processes of inflammation and apoptosis.PC12 cells were transfected with a pHBLV-U6-MCS-CMV-ZsGreen-PGK-PURO vector to express an lncRNA Vof-16 knockdown lentivirus and a pHLV-CMVIE-ZsGree-Puro vector to express an lncRNA Vof-16 overexpression lentivirus.The overexpression of lncRNA Vof-16 inhibited PC12 cell survival,proliferation,migration,and neurite extension,whereas lncRNA Vof-16 knockdown lentiviral vector resulted in the opposite effects in PC12 cells.Western blot assay results showed that the overexpression of lncRNA Vof-16 increased the protein expression levels of interleukin 6,tumor necrosis factor-α,and Caspase-3 and decreased Bcl-2 expression levels in PC12 cells.Furthermore,we established rat models of spinal cord injury using the complete transection at T10.Spinal cord injury model rats were injected with the lncRNA Vof-16 knockdown or overexpression lentiviral vectors immediately after injury.At 7 days after spinal cord injury,rats treated with lncRNA Vof-16 knockdown displayed increased neuronal survival and enhanced axonal extension.At 8 weeks after spinal cord injury,rats treated with the lncRNA Vof-16 knockdown lentiviral vector displayed improved neurological function in the hind limb.Notably,lncRNA Vof-16 knockdown injection increased Bcl-2 expression and decreased tumor necrosis factor-αand Caspase-3 expression in treated animals.Rats treated with the lncRNA Vof-16 overexpression lentiviral vector displayed opposite trends.These findings suggested that lncRNA Vof-16 is associated with the regulation of inflammation and apoptosis.The inhibition of lncRNA Vof-16 may be useful for promoting nerve regeneration and functional recovery after spinal cord injury.The experiments were approved by the Institutional Animal Care and Use Committee of Guangdong Medical University,China.

Salvianolic acid B protects the myelin sheath around injured spinal cord axons

Salvianolic acid B,an active pharmaceutical compound present in Salvia miltiorrhiza,exerts a neuroprotective effect in animal models of brain and spinal cord injury.Salvianolic acid B can promote recovery of neurological function;however,its protective effect on the myelin sheath after spinal cord injury remains poorly understood.Thus,in this study,in vitro tests showed that salvianolic acid B contributed to oligodendrocyte precursor cell differentiation,and the most effective dose was 20 μg/m L.For in vivo investigation,rats with spinal cord injury were intraperitoneally injected with 20 mg/kg salvianolic acid B for 8 weeks.The amount of myelin sheath and the number of regenerating axons increased,neurological function recovered,and caspase-3 expression was decreased in the spinal cord of salvianolic acid B-treated animals compared with untreated control rats.These results indicate that salvianolic acid B can protect axons and the myelin sheath,and can promote the recovery of neurological function.Its mechanism of action is likely to be associated with inhibiting apoptosis and promoting the differentiation and maturation of oligodendrocyte precursor cells.