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Objective To silence the beclin1 gene expression by using RNA interference technology in AR42J rat pancreatic acinar cells,and build a stable AR42J line silencing beclin1.Methods Three kinds of shRNA targeting rat beclin1 mRNA and negative control shRNA were designed and synthesized,and were inserted into the plasmids GV112,respectively.The recombinant plasmids were named as p-sh-Beclin1-1,psh-Beclin1-2,p-sh-Beclin1-3 and p-shRNA-NC.Lipo3000 was used to transfect the recombinant plasmid into AR42J cells,the expression of beclin1 mRNA were detected by RT-PCR to screen for the most efficient silencing plasmid,and then it was packaged into lentiviral (LV).AR42J cells were infected with LV and screened by puromycin.Beclin1 mRNA and protein expression was determined by RT-PCR and Western blot.Results The recombinant plasmid was confirmed by agarose gel electrophoresis and sequencing showed that shRNA sequences were in line with expectations.The beclin1 mRNA inhibition rates of AR42J cells after p-sh-Beclin1-1,p-sh-Beclin1-2,p-sh-Beclin1-3 and p-shRNA-NC transfection were (17.8 ± 4.0) ％,(30.6 ± 2.8) ％,(45.8 ± 7.7) ％,(7.0 ± 11.8) ％,respectively.The inhibition rates of three p-sh-Beclin1 transfection cells were significantly higher than that in non-transfection cells,and the difference was statistically significant (P ＜ 0.05).While the inhibition rate of p-shRNA-NC transfection cells was not significantly different from that of non-transfection cells,p-sh-Beclin 1-3 with highest rate of inhibition was packaged by LV,and infected AR42J cells,then puromycin was applied to screen,inhibition rate of beclin mRNA expression in LV infection cells was (86.1 ± 1.2) ％,and the protein expression inhibition rate was (87.9 ± 2.8) ％,and the difference between infection and non-infection groups was statistically significant (P ＜ 0.05).Conclusions The stable AR42J line silencing beclin1 is successfully established,which can provide a new cell model for future research of the role of beclin1 in the pathogenesis of acute pancreatitis.
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Objective To establish a stable AR42J cell line expressing EGFP LC3.Methods The EGFP LC3 overexpressed Lentivirus was constructed and transfected into pancreatic acinar cells (AR42J) of rats.The rats with Lentiviral EGFP transfection were treated as negative control.The transfection efficiency was detected by inverted fluorescence microscope and flow cytometry.The EGFP LC3 protein expression in the stable cell lines were analyzed by Western blot.The cells were treated with thapsigargin to establish endoplasmic reticulum stress model,and the LC3,PERK protein expressions were detected by Western blot.Results The transfection efficiency of Lentiviral EGFP LC3 of AR42J cell was ＞ 85％,which could achieve stable passage.The expression of LC3 mRNA of AR42J cells transfected with Lentiviral EGFP LC3 was 9.14 ±0.32 folds higher than that of negative control,which had no expression of LC3 protein,only EGFP expression.However,compared with non-transfection group,the LC3 mRNA expression in EGFP group was not significantly different.Conclusions A pancreatic acinar cell line (AR42J) of rat stably expressing EGFP LC3 protein is successfully constructed.And it may provide a new model for further research of the relationship between acute pancreatitis and autophagy.
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Objective To investigate the roles of toll like receptor7 (TLR7) and toll like receptor 9 (TLR9) in the pathogenesis of acute pancreatitis.Methods AR42J cells were treated by lipopolysaccharide at different dosages (0,1,10,100 mg/L),and cell model of acute pancreatitis in vitro was established.AR42J cells without lipopolysaccharide treatment were as control.Cells and culture supernatant were collected after 24 hours cultivation.TLR7,TLR9 mRNA and protein expressions were detected by RT-PCR and Western Blot,and levels of TNF-α,IL-10 in culture supernatant were measured by ELISA.Results The TLR 7 mRNA expression levels in control group,1,10,100 mg/L lipopolysaccharide group were 0.12 ± 0.09,0.28 ± 0.06,0.49 ± 0.04,0.78 ± 0.04,and the TLR9 mRNA expression levels were 0.06 ± 0.02,0.32 ± 0.03,0.56 ± 0.14,0.84 ± 0.12; the TLR7 protein expression levels were 0.04 ± 0.01,0.26 ± 0.05,0.49 ±0.04,0.77 ±0.16,and the TLR9 protein expression levels were 0.10 ±0.14,0.62 ±0.23,1.21 ± 0.26,1.75 ± 0.13 ; the TNF-α levels in culture supernatant were (8.01 ± 5.32),(25.64 ± 8.71),(49.06 ± 10.23),(75.83 ± 6.65) ng/L,and the IL-10 levels were (155.54 ± 25.47),(105.16 ± 10.49),(69.36 ± 8.19),(14.07 ± 9.06)ng/L.The expression levels of TLR7 and TLR9's mRNA,protein in cell,as well as the levels of TNF-α in culture supernatant increased with the lipopolysaccharide concentration,while the levels of IL-10 in culture supernatant decreased with the lipopolysaccharide concentration,and the difference among these groups was statistically significant (P ＜ 0.01).Conclusions The expressions of TLR7 and TLR9 in AR42J cells treated by using lipolysaccharide are obviously up-regulated,and it suggests that TLR7 and TLR9 may be vital in the pathogenesis of acute pancreatitis.
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Objective To investigate lipopolysaccharide (LPS) stimulates the expression of nuclear factor-KB (NF-κB) mRNA and tumor necrosis factor-a( TNF-α) mRNA in rat's pancreatic acinus AR42J cell line, and further address the pathogenesis of acute pancreatitis. Method The AR42J cell line was stimulated with different concentrations of LPS (0.001, 0.01, 0.1, 1.0, 10 and 100 mg/L) for 18 hours, or stimulated with 10 mg/L of LPS for different lengths of time (2, 6, 12,18 and 24 hrs) .Then, the expressions of NF-κB-P65 mRNA and TNF-α mRNA were determined by using RT-PCR, the levels of TNF-α protein in the culture supernatant were measured with radio-immuno assay (RIA), and the correlation between the expressions of TNF-α mRNA and NF-κB mRNA was analyzed. Results Both the expressions of NF-κB mRNA and TNF-α mRNA were up-regulated when AR42J cell line was stimulated with 10 mg/L of LPS for 2 hours or with 0.001 mg/L of LPS for 18 hours in both dose-dependent and time-dependent manners. Similarly, the levels of TNF-α protein were up-regulated when AR42J cell line was stimulated with 0.01 mg/L of LPS for 18 hours or with 10 mg/L of LPS for 6 hours in both dose-dependent and time-dependent manners. Statistical analysis revealed the positive correlation between the expressions of TNF-α mRNA and NF-κB-P65 mRNA(r = 0.962, P < 0.01). Conclusions LPS stimulates the expressions of TNF-α mRNA and NF-κB mRNA in both dose-dependent and time-dependent manners, and their expressions are closely correlated, suggesting the inhibition of their expressions as a potential therapeutic target for acute panceatitis.
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Objective To investigate the effects of Tat-NBD(NEMO-binding domain,NBD)peptide on LPS-stimulated AR42J acinus cells inflammatory response.Method Lipopolysaccharide(LPS)was added to culture media at doses of 10 mg/kg for 24 hours to stimulate the AR42J cells.For pretreatment.cells were incubated with different peptides for 2 hours before LPS stimulation.The expression of TNF-α mRNA WaS conducted using a semi-quantitative RT-PCR method.TNF-α protein in culture medium were detected by enzyme linked immunosorbent assay(ELISA).The expression and translocation of the NF-kB-p65 protein of AR42J was determined by Strept Actividin-Biotin Complex(SABC)method.Results LPS(10 mg/L)resulted in an increase of TNF-αmRNA and TNF-αprotein,whereas significant inhibitory effects were observed when cells were incubated with Tat-NBD(WT)just on dose of 0.1 me/L(P＜0.05).The Tat-NBD(WT)peptide decreased inflammatory cytokine expression by a dose-dependent manner and its peak role was on dose of 100 mg/L.Consisting with TNF-α expression decrease,NF-kB-p65 expression signitieantly decreased in Tat-NBD(WT)pretreatment group,especially on the largest dose.NO significant changes in the control peptide group.Conclusions Tat-NBD(WT)peptide can inhibit the inflammation of acinus simulated by LPS.