Treadmill training improves neural function recovery in rats with spinal cord injury via JAK2/STAT3 signaling pathway and attenuating apoptosis.

To investigate the role of JAK2/STAT3 signaling pathway in neural function recovery in rats with spinal cord injury (SCI) after treadmill training. Sprague-Dawley rats were randomly divided into four groups: (a) sham group; (b) SCI group; (c) SCI+treadmill training group (SCI/TT); and (d) SCI/TT+AG490 group (a JAK2 inhibitor) (n = 12). The 12 Sprague-Dawley rats in each group were randomly assigned into 1st, 3rd, 7th, and 14th day subgroups. The Basso-Beattie-Bresnahan (BBB) locomotor rating scale was used to assess the spinal cord function, and JAK2, STAT3, and IL-6 protein expressions in the rat spinal cord were evaluated by western blot. The level of cell apoptosis and expressions of apoptotic proteins were evaluated by TUNEL assay and immunohistochemistry, respectively. Rats in the SCI+TT group showed a significantly higher BBB score after SCI compared with the SCI group and the SCI/TT+AG490 group. Mechanistically, the JAK2/STAT3 signal pathway was immediately activated after SCI compared with sham group, and JAK2 and STAT3 were obviously upregulated when treadmill training was performed (P < 0.05). Results of TUNEL assay showed that the apoptotic rate in SCI/TT was significantly lower than that in the SCI group and SCI/TT+AG490 group (P < 0.05). Besides, the IL-6 expression in the SCI/TT group was significantly attenuated compared with the SCI group (P < 0.05). Our results showed that physical treadmill training can enhance activation of JAK2/STAT3 signal pathway and attenuate apoptosis in the injured spinal cord, resulting in better functional recovery. These results underline the importance of synergistic treatment strategies for SCI.

Microarray and Bioinformatics Analysis of Differential Gene and lncRNA Expression during Erythropoietin Treatment of Acute Spinal Cord Injury in Rats.

Purpose: We performed a genome-wide analysis of long noncoding RNA (lncRNA) expression to identify novel targets for the further study of recombinant human erythropoietin (rhEPO) treatment of acute spinal cord injury (SCI) in rats. Methods: Nine rats were randomly divided into 3 groups. No operation was performed in group 1. In groups 2 and 3, a laminectomy was performed at the 10th thoracic vertebra, and a contusion injury was induced by extradural application of an aneurysm clip. Group 1 rats did not receive any treatment, group 2 rats received a single intraperitoneal injection of normal saline, and group 3 rats received rhEPO. Three days after injury, spinal cord tissues were collected for RNA-Seq, microarray, differentially expressed genes (DEGs), Gene Ontology (GO) function enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and protein-protein interaction (PPI) analyses. Results: Compared with group 1, 4,446 genes were found to be differentially expressed in group 2. Furthermore, 99 lncRNAs were found to be changed in the injury group. The data indicate that 2,471 mRNAs were upregulated, and 1,975 mRNAs were downregulated in group 2 as compared with group 1. In addition, 45 of the lncRNAs were upregulated, and the other 44 lncRNAs were downregulated. The top 5 upregulated and top 5 downregulated lncRNAs that were different between group 2 and group 1 are shown. The top 5 downregulated and the top 5 upregulated lncRNAs that were different between group 3 and group 2 are shown. Conclusion: RhEPO treatment alters the expression profiles of the differentially expressed lncRNAs and genes beneficial to the development of new treatments.

LncRNA HOTTIP enhances human osteogenic BMSCs differentiation via interaction with WDR5 and activation of Wnt/ß-catenin signalling pathway.

To uncover the underlying molecular mechanism of long non-coding RNA in the osteogenic differentiation process of bone marrow mesenchymal stem cells (BMSCs), HOXA transcript at the distal tip (HOTTIP) was selected by using a lncRNA microarray assay. Results showed that HOTTIP was significantly upregulated during osteogenic differentiation of human BMSCs. Downregulation of HOTTIP by shRNA inhibited the osteogenic differentiation of BMSCs. Overexpression of HOTTIP by lentiviral vector promoted human BMSCs osteogenic differentiation by increasing the transcription of ß-catenin. RIP assay and RNA pulldown assay confirmed the interaction between HOTTIP and WDR5, a transcription factor binding to the promoter of ß-catenin. The interaction promoted the translocation of WDR5 into the nucleus and increased the transcription of ß-catenin. Implanted HOTTIP-overexpressing BMSCs increased ectopic bone formation in nude mice. HOTTIP is a conservative long noncoding RNA that is essential for osteogenic differentiation of BMSC. HOTTIP enhances osteogenic differentiation via interaction with WDR5 and up-regulation of ß-catenin gene expression, therefore activating Wnt/ß-catenin signalling pathway.