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@#Thioredoxin-interacting protein (TXNIP), which mainly regulates glucose homeostasis in pancreatic β cells, is a novel target in the treatment of diabetes.In this study, 4-hydroxybenzopyrimidine was used as the raw material, four nitrogen-containing rings (imidazole, methylpiperazine, pyrazole, morpholine) were introduced, benzopyrimidine skeleton with nitrogen-containing rings derivatives targeting TXNIP was designed and synthesized, and the protective effect of compounds on palmitic acid-stimulated islet β cells was investigated.A total of 20 benzopyrimidine derivatives were designed and synthesized, and the structures were confirmed by 1H NMR and ESI-MS.Pharmacological studies showed that most of the compounds exhibited protective effects on islet β cells, with better axtivity for compounds C-1, C-2, C-4 and D-2 (cell survival rate > 70%) compared with PA model group (38.3%), Among the four compounds, D-2 had the highest activity of 87.2%, so it could become a potential new anti-diabetic chemical entity.
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Objective To explore the effect of circadian rhythm genes on flavonoids biosynthesis in safflower and its molecular mechanism. Methods Based on the transcriptome and metabolomic database of safflower corolla, we screened the circadian rhythm genes that correlate with biosynthesis of flavonoids in safflower. qPCR was used to quantify the expressions of circadian rhythm genes in different flowering stages at different time points in a single day. LC-MS was performed to determine the accumulation of flavonoids. The correlation between them was analyzed as well. Yeast Two-Hybrid experiment was used to verify the interactive proteins of these genes. Results Seven circadian rhythm genes PRR1, PRR2, ELF3, FT, PHYB, GI and ZTL were obtained. PRR1 gene was positively correlated with flavonoids accumulation (r≥0.7). The full length of PRR1 is 3 201 bp, encoding 421 amino acids, which is highly homologous with rice OsPRR73 gene and named as CtPRR1 (GenBank accession number: MW492035). CtPRR1 was mainly expressed in flowers, and the expression level increased in the daytime and declined in the evening gradually. Correspondingly, the content of flavonoids showed an opposite variation. Both of them displayed a circadian rhythm with a negative correlation (r≥−0.7). In addition, 2 heat shock proteins along with 3 AP2 transcription factors interacting with CtPRR1 protein were obtained via Yeast Two-Hybrid experiment. Conclusion CtPRR1 negatively regulated the safflower flavonoids accumulation in a circadian rhythm way, which may be affected by these interacting proteins.
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UDP glucosyltransferase (UDPGT) catalyzes the synthesis of secondary metabolites and plant hormones to regulate plant growth and development, pathogen defense and environmental adaptability. In this study 18 members of the RcUDPGT gene family were cloned from Tibetan Rhodiola crenulata and analyzed using bioinformatics. The tissue-specific expression, abiotic stresses and plant hormones (abscisic acid, auxin, methyl jasmonate) induced expression patterns were identified by real-time quantitative PCR. The bait vector of RcUDPGT (JX228125.1) was constructed to select interacting proteins from an Arabidopsis yeast library. The results of the bioinformatics analysis revealed that RcUDPGT nucleotide sequences were about 1 400 bp and encoded 452-498 amino acids. In the primary protein sequences, C-terminal sequences were more conserved compared with N-terminal regions, which held a PSPG (plant secondary product glycosyltransferase) domain. In the tertiary structures, RcUDPGTs contained a UDP sugar donor recognition binding site. In addition, all genes had multiple phosphorylation sites. The results of qRT-PCR showed that RcUDPGTs genes were expressed in root, stem and leaf. The expression levels were regulated by low temperature/ultraviolet light and various plant hormones (ABA, IAA, MeJA), but the expression patterns were quite different among them. For example, RcUDPGT6, RcUDPGT11, and RcUDPGT17 had the highest expression in leaves and were induced by all three hormones, suggesting that the functions of these genes might be to respond to environmental changes. RcUDPGT9, RcUDPGT10, RcUDPGT14 were most abundantly expressed in roots and were significantly induced by ABA and MeJA hormones, indicating that these genes may be involved in the synthesis and accumulation of salidroside. Yeast two-hybrid results showed that RcUDPGT did not exhibit autoactivation and cell toxicity, and two significant interactional genes were identified, AtKCR1 (AT1G67730.1) and AtSNL4 (AT1G70060). The AtKCR1 gene encodes a β-ketoacyl reductase (KCR) involved in synthesis of very long chain fatty acids. The AtSNL4 gene encodes a homolog of the transcriptional repressor SIN3, which could participate in the ABA hormone signaling pathway and enhance the transcriptional repression of AP2/EREBP class factors in Arabidopsis. These results suggest that the accumulation of the secondary metabolite salidroside in Rhodiola crenulata might be affected by several regulatory mechanisms. The above results may lay the foundation for understanding the adaptive mechanism of Rhodiola crenulata in a high altitude environment and stimulate an in-depth study of the synthesis and accumulation of secondary metabolites in this species.
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Objective To evaluate the inductive effect of interferon-γ(IFN-γ) combined with tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) on programmed necrosis of the human immortalized keratinocyte cell line HaCaT,and to explore its mechanisms.Methods In vitro cultured HaCaT cells were divided into several groups:negative control group receiving no treatment,IFN-γ group treated with 50 μg/L IFN-γ,TRAIL group treated with 4 μg/L TRAIL,and cytokine combination group treated with 50 μg/L IFN-γ and 4 μg/L TRAIL or zVAD combination group pretreated with 40 μmo/L zVAD for 1 hour followed by the treatment with 50 μg/L IFN-γand 4 μg/L TRAIL.After 48-hour treatment,the morphology of HaCaT cells were observed under a light microscope,methyl-thiazolyl-tetrazolium assay was performed to evaluate the inhibitory effect of the treatment on the proliferation of HaCaT cells,and double staining flow cytometry to detect the necrosis of HaCaT cells.Meanwhile,real-time fluorescence-based quantitative PCR (qPCR) was conducted to determine the mRNA expression of receptor interaction protein kinase 3 (RIP3) and mixed lineage kinase domain-like protein (MLKL),Western blot analysis to determine the expression of RIP1,RIP3,MLKL proteins and their phosphorylated forms (pRIP1,pRIP3,pMLKL),immunofluorescent staining to observe the distribution of pRIP3 and pMLKL in HaCaT cells,and the level of reactive oxygen species (ROS) in HaCaT cells in the above groups was detected by the fluorescence probe DCFH-DA.Statistical analysis was carried out with SPSS 22 software by using one-way analysis of variance (ANOVA) for comparing indices among different groups,and least significant difference (LSD)-t test for multiple comparisons.Results After 48-hour treatment,HaCaT cells in the cytokine combination group and zVAD combination group showed necrosis-like morphologic features.Methyl-thiazolyl-tetrazoliumassay revealed significant differences in the survival rate of HaCaT cells among the IFN-γgroup,TRAIL group,cytokine combination group,zVAD combination group and negative control group (73.16％ ± 5.71％,81.46％ ± 4.68％,72.18％ ± 2.93％,69.67％ ± 3.24％ and 100％,respectively;F =24.34,P ＜ 0.001).The necrosis rate of HaCaT cells was notably higher in the cytokine combination group and zVAD combination group (9.86％ ± 1.31％,10.33％ ± 2.16％,respectively) than in the negative control group (5.26％ ± 0.91％,t =4.61,5.07,respectively,both P ＜ 0.05).qPCR revealed that the mRNA expression of RIP3 and MLKL significantly increased in the cytokine combination group and zVAD combination group compared with the negative control group (tRIP3 =0.99,1.84,tMLKL =1.51,2.17,respectively,all P ＜ 0.05).Western blot analysis suggested that the protein expression of RIP1,RIP3,MLKL,pRIP1,pRIP3 and pMLKL significantly increased in the cytokine combination group compared with the negative control group (all P ＜ 0.05),and the zVAD combination group showed significantly decreased caspase 8 expression and increased expression of the above proteins compared with the cytokine combination group.Fluorescence microscopy showed that enhanced green dot-like or clump-like fluorescent spots (representing pRIP3) could be observed in the cytoplasm,and red fluorescent spots (representing pMLKL) could be seen on the cell membrane in the cytokine combination group.The average fluorescence intensity of ROS was significantly higher in the cytokine combination group than in the negative control group (t =702.00,P ＜ 0.05).Conclusion IFN-γcombined with TRAIL can induce the programmed necrosis of HaCaT cells with increased level of ROS.
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OBJECTIVE: To study the effect of curcumin on the oxidative stress induced by nano-silicon dioxide( SiO_2) in A549 cells and to explore its potential mechanism. METHODS: A549 cells were randomly divided into 6 groups. Nano-SiO_2 group cells were stimulated with nano-SiO_2 solution with a final concentration of 20 mg/L; curcumin low-,medium-,and high-dose group cells were treated with curcumin at final concentrations of 5,10,and 20 μmol/L respectively and 20 mg/L nano-SiO_2 solution; the solvent control group was treated with dimethyl sulfoxide with a volume fraction of 0. 10%. The cells in the blank control group were not given any treatment. The cells in these 6 groups were incubated for 12 hours,and the level of malondialdehyde( MDA) and the activity of total superoxide dismutase( T-SOD) in the cells were measured by spectrophotometer. The relative expression of mRNA and protein of nuclear factor E2-associated factor 2( NRF2),thioredoxin-1( TRX1),and thioredoxin interaction protein( TXNIP) were analyzed by real-time fluorescent quantitative polymerase chain reaction and Western blot respectively. RESULTS: The MDA level in A549 cells of nano-SiO_2 group increased( P < 0. 05),the T-SOD activity decreased( P < 0. 05),and the mRNA and protein relative expression of NRF2 and TRX1 were up-regulated( P < 0. 05),TXNIP relative expression of mRNA and protein were down-regulated( P <0. 05),when compared with the blank control group and the solvent control group. After intervention with curcumin,with the increased of curcumin concentration,the MDA level in A549 cells decreased,the T-SOD activity increased,the relative expression of NRF2 mRNA and TRX1 mRNA and protein was up-regulated,the mRNA and protein relative expression of TXNIP was down-regulated,and showed a dose-dependent manner( P < 0. 01). CONCLUSION: Curcumin can protect nano-SiO_2-induced oxidative stress in A549 cells. It may activate TRX system by regulating NRF2/antioxidant response elements pathway,exerting an anti-oxidation effect and protecting cells from excessive oxidative damage.
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Objective To investigate the effect of TXNIP in renal ischemia-reperfusion injury induced apoptosis in human kidney proximal tubular cell line. Methods To build an injury model of HK-2 cells in vitro. The level of ROS and rate of apoptosis were analyzed by flow cytometry. The expression levels of proteins were observed by Western Blot. The expression level of TXNIP mRNA was observed by RT-qPCR. Results Compared with the control group,the level of ROS,the rate of cell apoptosis,the expression of cleaved caspase-3 significantly increased(P<0.01),and the expression of GPX4 significantly decreased in HK-2 cells in the OGD/R group(P<0.01).Compared with the OGD/R group,the expression of TXNIP protein and mRNA significantly decreased(P<0.01),the level of ROS,the rate of cell apoptosis significantly decreased(P<0.01),and the expression of GPX4 significantly increased in HK-2 cells in the siRNA TXNIP group(P < 0.01). Conclusion Down regulation of TXNIP can inhibit IRI-induced HK-2 apoptosis through activating GPX4 and decreasing ROS.
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Objective To study interaction proteins with secreted apoptosis-related protein 1 (SARP1) in fibroblasts of hypertrophic scar and to analyze its molecular mechanisms.Methods The recombinant adenovirus Ad-SARP1 was successfully constructed and transfected into the fibroblasts of hypertrophic scar in culture.The proteins were precipitated by immunoprecipitation and separated by SDS-PAGE,then it was stained with Coomassie blue and proteins from SDS-PAGE gel electrophoresis strip were analyzed with enzymolysis and mass spectrometric in turn.The peptide sequences were obtained according to mass spectrometry and the database were searched automatically.Results The results showed that in control cells,Ad-SARP1 and Ad-EGFP infected cells,were precipitated 7 protein bands,their molecular weights were about 93 × 103,43 × 103,40 × 103,37 × 103,31 × 103,26 × 103 and 12× 103,respectively; without SARP1 antibody the protein bands did not precipitate.Analysis of the 6 protein bands showed that proteins that might interact with SARP1 included periostin precursor (OSF-2),asporin precursor (PLAP1),phosphoglycerate kinase 1,rCG50690,apolipoprotein A-I precursor (Apo-AI),and thioredoxin 1 (TRX1).Conclusions The interaction proteins of SARP1 can be obtained by immunoprecipitation combined with liquid chromatography/mass spectrometry and ion trap detection technology.These results provide new clues for the mechanism of SARP1 regulates the apoptosis signal pathway of HSFb.
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Homo sapiens PDCD10(programmed cell death 10,alias,"TF-1 cell apoptosis related gene 15,TFAR15"),cloned by means of cDNA-representational differences analysis,had been initially identified associated with cell apoptosis.Recent research suggested mutations within the PDCD10 gene or deletion were responsible for cerebral cavernous malformations,and PDCD10 was the third CCM gene.On the other hand,other research demonstrated that PDCD10 was strictly modulated and up regulated in many kinds of tumors,which implicated that PDCD10 participated in tumorous signal transduction.The recent research confirmed that PDCD10 interacts with MST4,a member of Ste20-related kinases,and the interaction promoted cell proliferation and transformation via modulation of the ERK-MARK pathway.In conclusion,all these demonstrate that PDCD10 has many biological effects,which suggests that it is a novel player in vascular morphogenesis and/or remodeling,as well as tumorigenesis and cancer progression.
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Objective To screen the proteins interact with cytoplasmic tail of NECL1.Methods The cytoplasmic tail sequence of human NECL1 gene was inserted into the "bait" vector pGBKT7 in frame.The recombinant pGBKT7-NECL1C was then transformed into yeast cells and followed by screening of human fetal brain cDNA library.Then the GST pull down assay was used to confirm the interactions between the proteins.Results Nine different sequences by sequencing the positive clones and five alternative proteins were obtained by the amino acid sequence blast.Using the GST pull down analysis,we confirmed that two of them can interact with the cytoplasmic tail of NECL1 in vitro.Conclusion The alternative proteins obtained with the yeast dual-system may interact with the cytoplasmic tail of NECL1.