Intervertebral disc (IVD) degeneration is considered to be the main cause of low back pain (LBP),however,there are lack of long-lasting and effective methods of clinical treatment.Tissue engineering technique based on stem cells becomes an essential research direction on repair of IVD degeneration at present,and its effectiveness and feasibility have been confirmed,but it is difficult to maintain the sufficiency and vitality of stem cells in IVD.Previous studies showed that stem cells existed naturally in IVD,and stem cells from stem cell niche could migrate to IVD physiologically to maintain the IVD environment balance under the adverse microenvironment.Unfortunately,these behaviors cannot preclude IVD degeneration.Therefore,theoretical basis for the regeneration of nucleus pulposus (NP) in situ can be obtained from studying the mechanism that the endogenous repair failure during IVD degeneration,the cell death and the migration of stem cells in IVD,and the key regulatory targets to sustain the quantity and quality of the stem cells.Although there have been few researches to study the mechanism of the cell death and the migration of stem cells in IVD so far,studies demonstrated that the major inducing factors of IVD degeneration (pressure and hypoxia) could decrease the number of NP cells by autophagy,apoptosis and necroptosis,and chemokines and their receptors played a critical role in the migration of mesenchymal stem cells.These researches provide a clue for studying the mechanism of endogenous repair failure during IVD degeneration.We reviewed the current research situation and progress of the mechanism that endogenous repair failure during IVD degeneration in the following articles.First,we exhibited the potential of IVD stem cells in IVD degeneration repair.Second,the effect of the adverse microenvironment (pressure,hypoxia,etc) on the migration of IVD stem cells was discussed.Third,the mechanism of the stem cell death,autophagy,apoptosis and necroptosis under the adverse (pressure,hypoxia,etc.) microenvironment,and the correlation between the IVD stem cells migration and autophagy,apoptosis and necroptosis was studied.And then tissue engineering of NP was also discussed to achieve the endogenous repair of IVD degeneration.These studies will provide an innovative research direction on endogenous repair and a new strategy of early therapy for IVD degeneration.

Objective To explore the mechanism of drug resistance of ovarian cancer cells to TRAIL-induced apoptosis.Methods We collected 3AO cells and CAOV3 cells,respectively,at 18,24,48 and 72 hour under 12.5,25,50 and 100 ng/mL concentrations of TRAIL.The rate of cell growth inhibition was checked by methyl thiazolyl tetrazolium (MTT)assay to evaluate the effect of TRAIL.Morphology of apoptotic cells was observed by TdT-mediated-dUTP nick end labeling (TUNEL).The apoptosis rate was detected by flow cytometry (FCM)and C-FLIP protein was determined by Western blotting.Results TRAIL inhibited the growth of 3AO and CAOV3 cells.The rate of growth inhibition at 24 hour was 28% in 3AO cells and 10% in CAOV3 cells.TRAIL induced apoptosis of cells.The apoptosis rate at 24 hour was 8.5% in 3AO cells,which was higher than 5.5% in CAOV3 cells.The expression level of C-FLIP protein was higher in CAOV3 cells than in 3AO cells.Conclusion C-FLIP protein is an important protein that regulates drug resistance of ovarian cancer cells to TRAIL-induced apoptosis.

Objective To investigate the effect of knockdown of O-GlcNAc transferase (OGT) on hepatocyte fat synthesis.Methods Liver cell line L02 were used to established the model of hepatic steatosis.The levels of OGT and O-GlcNAc protein were detected by Western blot.The OGT knockdown cell line of L02 cells was established,and its lipid formation ability was detected after induction of oleic acid (OA).Real-time quantitative PCR (qRT-PCR) and Western blot were used to detect mRNA and protein expression of enzymes related to fat synthesis.An independent sample t test was used.Results Western blot showed that the expression of OGT and O-GlcNAc was increased in L02 cells after adipogenesis (P ＜ 0.05).After shOGT lentivirus infects L02 cells,OGT mRNA levels were down-regulated (P ＜ 0.01).Oil red O staining showed that the lipid in L02 shOGT cells decreased,qRT-PCR showed that the mRNA expressions of fat synthase (ACC1),(FASN) and (SCDl) were decreased,the difference was statistically significant (P ＜ 0.05),protein Expression is consistent with mRNA expression.Conclusion Knockdown of OGT can inhibit hepatocyte fat synthesis by reducing O-GlcNAc levels.

Objective: To investigate the safety and efficacy of 125I radioactive seed implantation in the treatment of mediastinal lymph node metastasis. Methods: Records of 53 patients enrolled in Shaanxi Provincial Tumor Hospital from June 2014 to June 2018 with me-diastinal lymph node metastasis treated by computed tomography (CT)-guided 125I seed implantation were analyzed retrospectively. The preoperative treatment planning system was validated after the surgery. Intraoperative and post-operative complications were re-corded. The improvement in quality of life was observed. Chest CT follow-up was conducted 1 month, 3 months, 6 months, 1 year, and 2 years after treatment. The local focus control was evaluated. The median survival and total survival were recorded, and the survival prognosis and causes of death were analyzed. Results: The median survival time was 254 days (8.5 months), one-year survival rate was 48.67%, and complete and partial response rate was 83.02% (44/53). Multivariate Cox model analysis showed that the survival progno-sis was related to the Eastern Cooperative Oncology Group (ECOG) score, distant metastasis at the time of implantation, concurrent chemotherapy after implantation, and secondary seed implantation (P<0.05). The rates of developing pneumothorax and hemoptysis during and after the surgery were 20.75% (11/55) and 13.20% (7/55), respectively. No patients died. After implantation, the remission rate of cough, shortness of breath, pain, hoarseness, and superior vena cava syndrome was 60.00%-82.61%. Conclusions: CT-guid-ed 125I seed implantation in the treatment of mediastinal lymph node metastasis has the advantages of minimal trauma, remarkable cu-rative effect, safety, and feasibility. It has important application value and is worthy of further clinical application.

Orofacial pain or tenderness is a primary symptom associated with temporomandibular joint (TMJ) disorders (TMDs). To understand the pathological mechanisms underlying TMDs, several mouse models have been developed, including mechanical stimulus-induced TMD and genetic mouse models. However, a lack of feasible approaches for assessing TMD-related nociceptive behaviours in the orofacial region of mice has hindered the in-depth study of TMD-associated mechanisms. This study aimed to explore modifications of three existing methods to analyse nociceptive behaviours using two TMD mouse models: (1) mechanical allodynia was tested using von Frey filaments in the mouse TMJ region by placing mice in specially designed chambers; (2) bite force was measured using the Economical Load and Force (ELF) system; and (3) spontaneous feeding behaviour tests, including eating duration and frequency, were analysed using the Laboratory Animal Behaviour Observation Registration and Analysis System (LABORAS). We successfully assessed changes in nociceptive behaviours in two TMD mouse models, a unilateral anterior crossbite (UAC)-induced TMD mouse model and a β-catenin conditional activation mouse model. We found that the UAC model and β-catenin conditional activation mouse model were significantly associated with signs of increased mechanical allodynia, lower bite force, and decreased spontaneous feeding behaviour, indicating manifestations of TMD. These behavioural changes were consistent with the cartilage degradation phenotype observed in these mouse models. Our studies have shown reliable methods to analyse nociceptive behaviours in mice and may indicate that these methods are valid to assess signs of TMD in mice.

The human Shwachman-Diamond syndrome (SDS) is an autosomal recessive disease caused by mutations in a highly conserved ribosome assembly factor SBDS. The functional role of SBDS is to cooperate with another assembly factor, elongation factor 1-like (Efl1), to promote the release of eukaryotic initiation factor 6 (eIF6) from the late-stage cytoplasmic 60S precursors. In the present work, we characterized, both biochemically and structurally, the interaction between the 60S subunit and SBDS protein (Sdo1p) from yeast. Our data show that Sdo1p interacts tightly with the mature 60S subunit in vitro through its domain I and II, and is capable of bridging two 60S subunits to form a stable 2:2 dimer. Structural analysis indicates that Sdo1p bind to the ribosomal P-site, in the proximity of uL16 and uL5, and with direct contact to H69 and H38. The dynamic nature of Sdo1p on the 60S subunit, together with its strategic binding position, suggests a surveillance role of Sdo1p in monitoring the conformational maturation of the ribosomal P-site. Altogether, our data support a conformational signal-relay cascade during late-stage 60S maturation, involving uL16, Sdo1p, and Efl1p, which interrogates the functional P-site to control the departure of the anti-association factor eIF6.
Crystallography, X-Ray ; GTP Phosphohydrolases ; chemistry ; metabolism ; Humans ; Protein Domains ; Ribosome Subunits, Large, Eukaryotic ; chemistry ; metabolism ; Saccharomyces cerevisiae ; chemistry ; metabolism ; Saccharomyces cerevisiae Proteins ; chemistry ; metabolism