Objective:To investigate the effect of triptolide on the apoptosis of human melanoma A375 cells through the inositol-requiring enzyme 1 (IRE1) /c-Jun N-terminal kinase (JNK) signaling pathway, and to explore its possible mechanisms.Methods:Cultured A375 cells were treated with triptolide at different concentrations of 0, 50, 100, 200 nmol/L (experimental control group, 50, 100, 200 nmol/L triptolide groups, respectively), and a blank control group (DMEM high-glucose medium without cells) was set up. Methyl thiazol tetrazolium (MTT) assay was performed to evaluate the cell viability at 24, 48, and 72 hours after the start of treatment, flow cytometry to detect cell apoptosis at 24 hours after the start of treatment, and real-time fluorescence-based quantitative PCR (RT-qPCR) and Western blot analysis were conducted to determine mRNA and protein expression of IRE1, JNK, and c-Jun, respectively. After pretreatment with the JNK inhibitor SP600125 for 72 hours, some A375 cells were then treated with 100 nmol/L triptolide for 24 hours (SP600125 + 100 nmol/L triptolide group), and the A375 cells only treated with 100 nmol/L triptolide served as control group (100 nmol/L triptolide group). Effects of triptolide on the mRNA expression of IRE1, JNK, and c-Jun in A375 cells, as well as on cell apoptosis, were investigated. Statistical analysis was performed using two-way analysis of variance, one-way analysis of variance, and Dunnett′s test.Results:After the treatment with different concentrations of triptolide for different durations, the cell viability was significantly lower in all triptolide groups than in the experimental control group ( Ftriptolide concentration = 18.36, P = 0.002), and gradually decreased over time ( F time = 8.54, P = 0.018). After 24-hour treatment, the apoptosis rate of A375 cells significantly differed among the 4 groups treated with different concentrations of triptolide ( F = 5 234.97, P < 0.001) ; additionally, the apoptosis rate was significantly higher in the 50, 100, and 200 nmol/L triptolide groups (16.99% ± 0.33%, 30.78% ± 0.40%, 38.91% ± 0.51%, respectively) than in the experimental control group (4.33% ± 0.02%, all P < 0.05), and gradually increased with the rising concentrations of triptolide. The mRNA expression levels of IRE1, JNK, and c-Jun were all significantly higher in the 50, 100, and 200 nmol/L triptolide groups than in the experimental control group (all P < 0.05), and gradually increased with the increase of triptolide concentration. Moreover, the protein expression levels of IRE1, JNK, c-Jun, p-JNK, and p-c-Jun in A375 cells in the triptolide groups also showed the same trend. After pretreatment with the JNK inhibitor SP600125 for 72 hours, the apoptosis rate was significantly lower in the SP600125 + 100 nmol/L triptolide group (21.88% ± 0.55%) than in the 100 nmol/L triptolide group without SP600125 pretreatment (30.78% ± 0.40%, t = -22.51, P < 0.001), and the mRNA expression levels of IRE1, JNK, and c-Jun were also significantly decreased in the SP600125 + 100 nmol/L triptolide group compared with the 100 nmol/L triptolide group (all P < 0.05) . Conclusion:Triptolide may induce apoptosis of human melanoma A375 cells by activating the IRE1/JNK signaling pathway.

A limited number of microRNAs (miRNAs, miRs) have been reported to control postnatal cardiomyocyte proliferation, but their strong regulatory effects suggest a possible therapeutic approach to stimulate regenerative capacity in the diseased myocardium. This study aimed to investigate the miRNAs responsible for postnatal cardiomyocyte proliferation and their downstream targets. Here, we compared miRNA profiles in cardiomyocytes between postnatal day 0 (P0) and day 10 (P10) using miRNA arrays, and found that 21 miRNAs were upregulated at P10, whereas 11 were downregulated. Among them, miR-31a-5p was identified as being able to promote cardiomyocyte proliferation as determined by proliferating cell nuclear antigen (PCNA) expression, double immunofluorescent labeling for α-actinin and 5-ethynyl-2-deoxyuridine (EdU) or Ki-67, and cell number counting, whereas miR-31a-5p inhibition could reduce their levels. RhoBTB1 was identified as a target gene of miR-31a-5p, mediating the regulatory effect of miR-31a-5p in cardiomyocyte proliferation. Importantly, neonatal rats injected with a miR-31a-5p antagomir at day 0 for three consecutive days exhibited reduced expression of markers of cardiomyocyte proliferation including PCNA expression and double immunofluorescent labeling for α-actinin and EdU, Ki-67 or phospho-histone-H3. In conclusion, miR-31a-5p controls postnatal cardiomyocyte proliferation by targeting RhoBTB1, and increasing miR-31a-5p level might be a novel therapeutic strategy for enhancing cardiac reparative processes.
Animals ; Cell Count ; MicroRNAs ; Myocardium ; Myocytes, Cardiac* ; Negotiating ; Proliferating Cell Nuclear Antigen ; Rats

An auxiliary dining robot is designed in this paper, which implements the humanoid feeding function with theory of inventive problem solving (TRIZ) theory and aims at the demand of special auxiliary nursing equipment. Firstly, this robot simulated the motion function of human arm by using the tandem joints of the manipulator. The end-effector used a motor-driven spoon to simulate the feeding actions of human hand. Meanwhile, the eye in hand installation style was adopted to instead the human vision to realize its automatic feeding action. Moreover, the feeding and drinking actions of the dining robot were considered comprehensively with the flexibility of spatial movement under the lowest degree of freedom (DOF) configuration. The structure of the dining robot was confirmed by analyzing its stresses and discussing the specific application scenarios under this condition. Finally, the simulation results demonstrate high-flexibility of the dining robot in the workspace with lowest DOF configuration.
Computer Simulation ; Equipment Design ; Hand ; Humans ; Movement ; Robotics/methods*