Induction of UGT1A6 isoform by inflammatory conditions in rat astrocytes.
Alteration of drug metabolism under diseased conditions is of clinical importance. We have investigated the effects of inflammatory conditions on phase II drug-metabolizing enzyme activity in rat cultured astrocytes. Lipopolysaccharide (LPS) treatment was used to promote inflammatory conditions. Thus, we reported that LPS initiates an inflammatory response, which is mediated by pro-inflammatory mediators and free radical generation. An increase in astrocyte glucuronidation activity was observed after a 48-h LPS treatment. This increase in glucuronidation activity was associated with an up-regulation of the UGT1A6 isoform mRNA level as shown by RT-PCR and gene reporter assay. Moreover, this endotoxin-induced increase in UGT1A6 expression level was blocked by actinomycin D and cycloheximide, indicating the requirement for RNA and protein synthesis. The UGT1A6 expression enhancement could be prevented by anti-inflammatory drugs (dexamethasone and NS398) or nitric oxide synthase inhibitors (L-NAME and L-NMMA). Moreover, gel shift assay revealed increased activator protein-1 (AP-1) binding activity after LPS treatment. We propose, based on the data presented, that the action of LPS to induce UGT1A6 isoform up-regulation may be mediated by pro-inflammatory mediator accumulation, and AP-1 binding activity increase.
Heurtaux
T
T
Unité Mixte de Recherche CNRS - Université Henri Poincaré Nancy 1, No 7561, Laboratoire de Pharmacologie, Faculté de Médecine, BP 184, 54505 Vandoeuvre-lès-Nancy Cedex, France.
Benani
A
A
Moulin
D
D
Muller
N
N
Netter
P
P
Minn
A
A
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects* / Q000201:enzymology; D015152:Blotting, Northern; D002470:Cell Survival / Q000187:drug effects; D015232:Dinoprostone / Q000378:metabolism; D004347:Drug Interactions; D004790:Enzyme Induction / Q000187:drug effects* / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D014453:Glucuronosyltransferase / Q000096:biosynthesis* / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000096:biosynthesis; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism*; D007375:Interleukin-1 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D016296:Mutagenesis / Q000502:physiology; D009154:Mutation; D009573:Nitrites / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013997:Time Factors; D014162:Transfection / Q000379:methods; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007375:Interleukin-1; D008070:Lipopolysaccharides; D009573:Nitrites; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D049452:Green Fluorescent Proteins; D014453:Glucuronosyltransferase; C107611:UDP-glucuronosyltransferase, UGT1A7; D015232:Dinoprostone