RESUMO
Objective @#To investigate the role of hepatic long-chain non-coding RNA (lncRNA) H19 in key genes associated with glucose metabolism disorder induced by p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE).@*Methods@#Human embryonic liver CCC-HEL-1 cells were divided into the DMSO group, 0.1 μmol/L p,p′-DDE group, 1 μmol/L p,p′-DDE group, 10 μmol/L p,p′-DDE group, small interference RNA (siRNA)+DMSO group and siRNA+10 μmol/L p,p′-DDE group. The promoter region methylation, mRNA expression and protein expression of hepatocyte nuclear factor 4α (HNF4α), forkhead box transcription factor O1 (FoxO1) and insulin-like growth factor (IGF2) were detected in CCC-HEL-1 cells using the bisulfite method, real-time fluorescence quantitative PCR (qPCR) assay and BCA assay, respectively. The changes in H19 mRNA expression, the methylation of associated genes in the promoter region and transcriptional expression were compared in CCC-HEL-1 among groups.@*Results@#Exposure to p,p′-DDE alone at different doses resulted in an increase in H19 expression, and the H19 mRNA expression was higher in the 10 μmol/L p,p′-DDE group than in the DMSO group [(1.31±0.25) vs. (1.02±0.22); P<0.05]. Lower methylation of the HNF4α gene in the pro moter region [(38.59±32.77)% vs. (61.43±24.64)%; P<0.05] and higher HNF4α mRNA expression [(1.33±0.26) vs. (1.03±0.28); P<0.05] were detected in the 10 μmol/L p,p′-DDE group than in the DMSO group, while no significant differences were detected between the two groups in terms of the methylation of FoxO1 and IGF2 genes in the promoter region, FoxO1 and IGF2 mRNA and protein expression (P>0.05). Following siRNA-induced H19 knockdown, higher methylation of the HNF4α gene in the promoter region [(71.33±22.23)% vs. (38.59±32.78)%; P<0.05], lower HNF4α mRNA expression [(0.71±0.17) vs. (1.33±0.26); P<0.05], higher methylation of FoxO1 gene in the promoter region [(47.73±34.24)% vs. (25.09±25.35)%; P<0.05] and higher IGF2 mRNA [(1.39±0.25) vs. (0.80±0.20); P<0.05] were found in the siRNA+DMSO group than in the 10 μmol/L p,p′-DDE group, and higher IGF2 protein expression was detected in the siRNA+DMSO group than in the DMSO group [(1.03±0.11) vs. (0.74±0.12); P<0.05]. @*Conclusion@#Hepatic H19 may alter HNF4α, FoxO1 and IGF2 transcription and expression through mediating the methylation of genes in the promoter region, thereby playing a role in p,p′-DDE-induced glucose metabolism disorders.
RESUMO
1,3-propanediol production with the byproduct of biodiesel production is important to increase the economic benefit of biodiesel industry. Accumulation of 3-hydroxypropionaldehyde is one of the key problems in the 1,3-propanediol fermentation process, leading to the cell death and the fermentation abnormal ceasing. Different from the traditional way of reducing the accumulation of the 3-hydroxypropionaldehyde, we introduced the polyhydroxybutyrate pathway into the Klebsiella pneumoniae for the first time to enhance the tolerance of K. pneumoniae to 3-hydroxypropionaldehyde, at the same time, to improve the 1,3-propanediol production. Plasmid pDK containing phbC, phbA, phbB gene was constructed and transformed into K. pneumoniae successfully. PHB was detected in the engineered K. pneumoniae after IPTG induction and its content enhanced with the IPTG concentration increasing. The optimized IPTG concentration was 0.5 mmol/L. The constructed K. pneumoniae could produce 1,3-propanediol normally, at the same time accumulate polyhydroxybutyrate. With the constructed strain, the fermentation proceeds normally with the initial glucose was 70 g/L which the wild type strain stopped growing and the fermentation was ceasing; 1,3-propanediol concentration and yield reached 31.3 g/L and 43.9% at 72 h. Our work is helpful for the deep understanding of 1,3-propanediol metabolic mechanism of Klebsiella pneumoniae, and also provides a new way for strain optimization of Klebsiella pneumoniae.