Different protein expression patterns in rat spinal nerves during Wallerian degeneration assessed using isobaric tags for relative and absolute quantitation proteomics profiling.

Sensory and motor nerve fibers of peripheral nerves have different anatomies and regeneration functions after injury. To gain a clear understanding of the biological processes behind these differences, we used a labeling technique termed isobaric tags for relative and absolute quantitation to investigate the protein profiles of spinal nerve tissues from Sprague-Dawley rats. In response to Wallerian degeneration, a total of 626 proteins were screened in sensory nerves, of which 368 were upregulated and 258 were downregulated. In addition, 637 proteins were screened in motor nerves, of which 372 were upregulated and 265 were downregulated. All identified proteins were analyzed using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis of bioinformatics, and the presence of several key proteins closely related to Wallerian degeneration were tested and verified using quantitative real-time polymerase chain reaction analyses. The differentially expressed proteins only identified in the sensory nerves were mainly relevant to various biological processes that included cell-cell adhesion, carbohydrate metabolic processes and cell adhesion, whereas differentially expressed proteins only identified in the motor nerves were mainly relevant to biological processes associated with the glycolytic process, cell redox homeostasis, and protein folding. In the aspect of the cellular component, the differentially expressed proteins in the sensory and motor nerves were commonly related to extracellular exosomes, the myelin sheath, and focal adhesion. According to the Kyoto Encyclopedia of Genes and Genomes, the differentially expressed proteins identified are primarily related to various types of metabolic pathways. In conclusion, the present study screened differentially expressed proteins to reveal more about the di?erences and similarities between sensory and motor nerves during Wallerian degeneration. The present findings could provide a reference point for a future investigation into the differences between sensory and motor nerves in Wallerian degeneration and the characteristics of peripheral nerve regeneration. The study was approved by the Ethics Committee of the Chinese PLA General Hospital, China (approval No. 2016-x9-07) in September 2016.

Efficacy of mesenchymal stem cells in treating patients with osteoarthritis of the knee: A meta-analysis.

To assess the clinical efficacy and safety of mesenchymal stem cell (MSC) treatment for osteoarthritis of the knee (KOA), a systematic electronic literature search was performed on PubMed, EMBASE and Web of Science. Studies published in English from the earliest record to December 2014 were searched using the following keywords: Cartilage defect, cartilage repair, osteoarthritis, KOA, stem cells, MSCs, bone marrow concentrate (BMC), adipose-derived mesenchymal stem cells, synovial-derived mesenchymal stem cells and peripheral blood-derived mesenchymal stem cells. The effect sizes of selected studies were determined by extracting pain scores from the visual analog scale and functional changes from International Knee Documentation Committee and Lysholm and Western Ontario and McMaster Universities Osteoarthritis Index before and after MSCs or reference treatments at 3, 6, 12, and 24 months. The factors were analyzed and the outcomes were modified after comparing the MSC group pooled values with the pretreatment baseline or between different treatment arms. A systematic search identified 18 clinical trials on this topic, including 10 single-arm prospective studies, four quasi-experimental studies and four randomized controlled trials that used BMCs to treat 565 patients with KOA in total. MSC treatment in patients with KOA showed continual efficacy for 24 months compared with their pretreatment condition. Effectiveness of MSCs was improved at 12 and 24 months post-treatment, compared with at 3 and 6 months. No dose-responsive association in the MSCs numbers was demonstrated. However, patients with arthroscopic debridement, activation agent or lower degrees of Kellgren-Lawrence grade achieved improved outcomes. MSC application ameliorated the overall outcomes of patients with KOA, including pain relief and functional improvement from basal evaluations, particularly at 12 and 24 months after follow-up.

Effect of lentivirus-mediated uPA silencing on the proliferation and apoptosis of chondrocytes and the expression of MMPs.

The lentivirus-mediated uPA interference in the proliferation, apoptosis, and secretion of osteoarthritic chondrocytes was examined in this study. Cells were obtained from the cartilage tissues of New Zealand white rabbits. They were cultured with interleukin (IL)-1ß (10 ng/mL) for 24 h and then divided into three groups: uPA-siRNA group (cells transfected with uPA-siRNA lentiviruses), blank control group (untreated cells), and negative control group (cells transfected with empty vectors). Western blotting and real-time quantitative reverse transcription-PCR (RT-QPCR) were performed to detect the protein and mRNA expression levels of uPA, MMP-1, MMP-3, MMP-9, MMP-10, MMP-13 and MMP-14 in osteoarthritic chondrocytes. Cell Counting Kit-8, flow cytometry, and colony formation assay were used to examine the proliferation and apoptosis of chondrocytes. The results showed that after uPA-siRNA transfection, the protein and mRNA expression levels of uPA, MMP-1, MMP-3, MMP-9, MMP-10, MMP-13, and MMP-14 were significantly decreased (P<0.05 for MMP-1, MMP-9, MMP-10 and MMP-14, P<0.01 for uPA, MMP-3 and MMP-13). Cell proliferation and colony formation rate were significantly higher and the cell apoptosis rate was significantly lower in uPA-siRNA group than in control groups (P<0.01). The proportion of cells in G0/G1 phase was markedly increased and that in the S phase decreased, and the cell cycle was arrested at the G1/S phase in the control group. In the uPA-siRNA group, the proportion of cells in the S phase was significantly increased, resulting in a different proportion of cells in cell cycle phase (P<0.01). It was suggested that the down-regulation of uPA gene could inhibit the expression of MMPs protein and cell apoptosis, increase the proliferation and colony formation of osteoarthritic chondrocytes.

Construction and verification of the targeted uPA-shRNA lentiviral vector and evaluation of the transfection and silencing rate.

Urokinase-type plasminogen activator (uPA) receptors, which are released by the synovial tissue, are responsible for the activation of cartilage-breakdown proteases and play critical roles in cartilage degradation during the progression of osteoarthritis (OA). RNA interference (RNAi) technology has emerged as a potent tool to generate cellular knockdown phenotypes of a desired gene. The aims of the present study were to investigate the effect of siRNA specific to the uPA gene on chondrocytes and to investigate the possible mechanisms of OA. Firstly, four types of small hairpin RNA (shRNA) sequence (P1, P2, P3 and P4) were obtained from the targeted uPA gene of the New Zealand rabbit, based on siRNA theory. The sequences were designed, constructed and subjected to restriction enzyme digestion, transformation, polymerase chain reaction (PCR) identification, positive clone sequencing and lentivirus packaging. Secondly, primary culturing cartilage cells from the New Zealand rabbit were transfected with P1, P2, P3 or P4 to observe the transfection rate under a fluorescence microscope. The mRNA expression levels of uPA were analyzed in cartilage cells using quantitative PCR, while protein expression levels were analyzed in the cartilage cells using western blot technology. Four types of uPA-shRNA lentiviral vectors were constructed successfully, which were all able to be transfected into the primary culturing cartilage cells. The transfection rate was as high as 85% when the multiplicity of infection was 100, which demonstrated that P1, P2, P3 and P4 were all capable of inhibiting the mRNA and protein expression of uPA in cartilage cells. In addition, among the four sequences, the P2 sequence exhibited the highest silencing rate of 70%. Statistical significance (P<0.05) was observed when analyzing the silencing rate of P2 compared to the other three groups. The most efficient targeted uPA-shRNA sequence was identified following screening. The results strongly verified that siRNA lentiviral vectors can be transfected into cartilage cells to further inhibit the expression of the uPA gene efficiently and steadily. Thus, the results provide the foundation for further research on the role of uPA in the pathogenesis of OA.