西亚试剂：MicroRNA-22 Can Reduce Parathymosin Expression

MicroRNA-22 Can Reduce Parathymosin Expression in Transdifferentiated Hepatocytes

Hung-Lin Chen, Jyun-Yuan Huang, Chun-Ming Chen, Tien-Hua Chu, Chiaho Shih.

Pancreatic acinar cells AR42J-B13 can transdifferentiate into hepatocyte-like cells permissive for efficient hepatitis B virus (HBV) replication.Here, we profiled miRNAs differentially expressed in AR42J-B13 cells before and after transdifferentiation to hepatocytes, using chip-based microarray.Significant increase of miRNA expression, including miR-21, miR-22, and miR-122a, was confirmed by stem-loop real-time PCR and Northern blot analyses. In contrast, miR-93, miR-130b, and a number of other miRNAs, were significantly reduced after transdifferentiation.To investigate the potential significance of miR-22 in hepatocytes, we generated cell lines stably expressing miR-22. By 2D-DIGE, LC-MS/MS, and Western blot analyses, we identified several potential target genes of miR-22, including parathymosin.In transdifferentiated hepatocytes, miR-22 can inhibit both mRNA and protein expression of parathymosin, probably through a direct and an indirect mechanism. We tested two computer predicted miR-22 target sites at the 3′ UTR of parathymosin, by the 3′ UTR reporter gene assay.Treatment with anti-miR-22 resulted in significant elevation of the reporter activity. In addition, we observed an in vivo inverse correlation between miR-22 and parathymosin mRNA in their tissue distribution in a rat model.The phenomenon that miR-22 can reduce parathymosin protein was also observed in human hepatoma cell lines Huh7 and HepG2. So far, we detected no major effect on several transdifferentiation markers when AR42J-B13 cells were transfected with miR-22, or anti-miR-22, or a parathymosin expression vector, with or without dexamethasone treatment.Therefore, miR-22 appears to be neither necessary nor sufficient for transdifferentiation. We discussed the possibility that altered expression of some other microRNAs could induce cell cycle arrest leading to transdifferentiation.