Changes of micro-RNA expression in rat liver treated by acetaminophen or carbon tetrachloride--regulating role of micro-RNA for RNA expression.
Recently, microRNAs, involved in RNA interference, were discovered as a new gene regulation, with little is known in the filed of toxicology. In this study, a toxic dose of acetaminophen or carbon tetrachloride was administered singly to male rats, and microarry analysis using mirVana miRNA bioarray was performed. Partial least squares-discriminant analysis of the microarray data revealed that microRNAs expression was specifically changed by treatments at 6 hr after dosing. Furthermore, we focused on miR298 and miR370 among the microRNAs commonly affected by hepatotoxicants, because they were speculated to regulate an oxidative stress-related gene. From real-time RT-PCR analysis, microRNAs expression was suppressed by hepatotoxicants at 6 and 24 hr. Regarding acetaminophen, the decreases were found even though there were no morphological changes in the liver at 6 hr. To investigate these 2 microRNAs in more detail, we measured their expression, WST-1 for mitochondrial function and LDH release for cell collapse in primary cultured hepatocytes exposed to several concentrations of acetaminophen for 3 hr. At more than 5 mM, the microRNA expression and WST-1 decreased, whereas LDH was unchanged. Therefore, the change in microRNA expression occurred at the time when mitochondrial function was damaged prior to cell collapse. From all the above findings, we conclude that microRNAs were affected by hepatotoxicants and that the changes were found in the early phase of toxicity. Thus, our data suggest microRNAs have an important role for toxicological mechanism and we proposed that the changes in microRNA expression might be key molecules for toxicity expression.
Fukushima
Tamio
T
Drug Safety Research and Development, Nagoya Laboratories, Pfizer Japan Inc., Aichi, Japan. fukushta@yahoo.co.jp
Hamada
Yoshimasa
Y
Yamada
Hiroshi
H
Horii
Ikuo
I
D000082:Acetaminophen / Q000633:toxicity*; D000818:Animals; D002251:Carbon Tetrachloride / Q000633:toxicity*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects*; D022781:Hepatocytes / Q000187:drug effects; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D011919:Rats, Inbred Strains; D020133:Reverse Transcriptase Polymerase Chain Reaction
D035683:MicroRNAs; D000082:Acetaminophen; D002251:Carbon Tetrachloride