Orphan receptors chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) and retinoid X receptor (RXR) activate and bind the rat cholesterol 7alpha-hydroxylase gene (CYP7A).
Animals; Rats; *Gene Expression Regulation; Cholesterol 7-alpha-Hydroxylase/*genetics/metabolism; Nuclear Proteins/*metabolism; Chickens; Transcription Factors/*metabolism; DNA-Binding Proteins/*metabolism; Retinoid X Receptors; COUP Transcription Factor II; COUP Transcription Factors; Circadian Rhythm; COUP Transcription Factor I; Recombinant Proteins/genetics/metabolism; Receptors; Models; Genetic; Enzymologic; Molecular; Electrophoresis; Polyacrylamide Gel; Promoter Regions; *Receptors; Steroid; Glucocorticoid/*genetics; Retinoic Acid/*metabolism
The cholesterol 7alpha-hydroxylase gene (CYP7A) is transcriptionally regulated by a number of factors, including hormones, bile acids, and diurnal rhythm. Previous studies have identified a region from nucleotides (nt) -74 to -55 of the rat CYP7A promoter that enhanced bile acid repression of the SV40 early promoter, as assayed with a luciferase reporter gene in transiently transfected HepG2 cells. The rat CYP7A promoter/reporter activity was strongly stimulated by cotransfection with an expression plasmid encoding the nuclear hormone receptor chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) in a dose-dependent manner. Site-directed mutagenesis in the region of nt -74 to -55 altered this stimulation. Recombinant COUP-TFII expressed in HepG2 or COS-1 cells were found to bind to nt -74 -55 and nt -149 -128 probes by electrophoretic mobility shift assay (EMSA) and by supershifting the corresponding band with
Stroup D; Crestani M; Chiang J Y
The Journal of biological chemistry
1997
1997-04
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
miR-217 regulates ethanol-induced hepatic inflammation by disrupting sirtuin
Alcoholic/genetics/*metabolism; Animals; Chromatin Immunoprecipitation; Enzyme-Linked Immunosorbent Assay; Ethanol/toxicity; Fatty Liver/metabolism; Hepatitis; Immunoblotting; Inbred C57BL; Inflammation/genetics/*metabolism; Kupffer Cells/metabolism; Lipopolysaccharides/toxicity; Male; Mice; MicroRNAs/*metabolism; Nuclear Proteins/*metabolism; Phosphatidate Phosphatase/*metabolism; Real-Time Polymerase Chain Reaction; Signal Transduction/*physiology; Sirtuin 1/*metabolism; Transfection
Ethanol-mediated injury, combined with gut-derived lipopolysaccharide (LPS), provokes generation of proinflammatory cytokines in Kupffer cells, causing hepatic inflammation. Among the mediators of these effects, miR-217 aggravates ethanol-induced steatosis in hepatocytes. However, the role of miR-217 in ethanol-induced liver inflammation process is unknown. Here, we examined the role of miR-217 in the responses to ethanol, LPS, or a combination of ethanol and LPS in RAW 264.7 macrophages and in primary Kupffer cells. In macrophages, ethanol substantially exacerbated LPS-mediated induction of miR-217 and production of proinflammatory cytokines compared with LPS or ethanol alone. Consistently, ethanol administration to mice led to increases in miR-217 abundance and increased production of inflammatory cytokines in isolated primary Kupffer cells exposed to the combination of ethanol and LPS. miR-217 promoted combined ethanol and LPS-mediated inhibition of sirtuin 1 expression and activity in macrophages. Moreover, miR-217-mediated sirtuin 1 inhibition was accompanied by increased activities of two vital inflammatory regulators, NF-kappaB and the nuclear factor of activated T cells c4. Finally, adenovirus-mediated overexpression of miR-217 led to steatosis and inflammation in mice. These findings suggest that miR-217 is a pivotal regulator involved in ethanol-induced hepatic inflammation. Strategies to inhibit hepatic miR-217 could be a viable approach in attenuating alcoholic hepatitis.
Yin Huquan; Liang Xiaomei; Jogasuria Alvin; Davidson Nicholas O; You Min
The American journal of pathology
2015
2015-05
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.ajpath.2015.01.030" target="_blank" rel="noreferrer noopener">10.1016/j.ajpath.2015.01.030</a>