The prediction of drug metabolism using scaffold-mediated enhancement of the induced cytochrome P450 activities in fibroblasts by hepatic transcriptional regulators.

A reliable, reproducible, and convenient in vitro platform for drug metabolism determination and toxicity prediction is of tremendous value but still lacking. In the present study, a collection of 24 hepatic transcription factors and nuclear receptors in different combinations were surveyed, and 10 among them were finally selected to induce the expression and enzyme activities of cytochrome P450 (CYP) 3A4, 1B1, and 2C9 in human dermal fibroblasts (HDFs). The expression and activities of these CYPs in the induced HDFs were higher than those in commonly used hepatoma cell lines.

Novel intronic microRNA represses zebrafish myf5 promoter activity through silencing dickkopf-3 gene.

A strong, negative cis-element located at the first intron +502/+835 (I300) of zebrafish myf5 has been reported. To elucidate the molecular mechanism underlying this repression network, we microinjected zebrafish single-cell embryos with I300 RNA, resulting in the dramatic reduction of luciferase activity driven by the myf5 promoter. Within this I300 segment, we identified an intronic microRNA (miR-In300) located at +609/+632 and found that it was more highly expressed in the older mature somites than those newly formed, which negatively correlated with the distribution of zebrafish myf5 transcripts.