21 In conclusion, the more potent effects of PAS compared to OCT on hepatorenal cystogenesis observed in this study are likely related to a combination of features of both the drug and the cystic cell phenotype including: (1) a broader range of SSTRs targeted by PAS; (2) a higher affinity of PAS
to SSTR3 and SSTR5 (expression of which in cystic cholangiocytes is unchanged compared to control); and (3) the extended half-life CT99021 in vivo of PAS. Our data suggest that PAS may be more effective for the treatment of PLD and PKD than OCT. A clinical trial (NCT01670110) to assess the effectiveness of PAS in hepatorenal cystogenesis in patients with ADPKD and ADPLD is now under way at our institution. Additional Supporting Information may be found in the online version of this article. “
“MicroRNA-122 (miR-122) is a liver-specific microRNA whose expression is specifically turned on in the mouse liver during embryogenesis, thus it is expected to be involved in liver development. However, the role of miR-122 in liver development and its potential underlying
mechanism remain unclear. Here, we show that the expression of miR-122 is closely correlated with four liver-enriched transcription factors (LETFs)—hepatocyte nuclear factor (HNF) 1α, HNF3β, HNF4α, and CCAAT/enhancer-binding protein (C/EBP) α—in the livers of developing mouse embryos and in human hepatocellular carcinoma (HCC) cell lines. Correspondingly, promoter analysis revealed that these
LETFs are coordinately involved in the transcriptional regulation of miR-122, and three HNFs directly bind to the miR-122 promoter CP-690550 manufacturer as transcriptional activators. Using a luciferase reporter system, we identified a group of miR-122 targets involved in proliferation and differentiation regulation. Among these targets, the most prominently repressed target was CUTL1, a transcriptional repressor of genes specifying terminal differentiation in multiple cell lineages, including hepatocytes. We show that CUTL1 expression is gradually silenced at the posttranscriptional level during mouse liver development. Overexpression and knockdown studies both showed that miR-122 repressed CUTL1 protein expression in HCC cell lines. Finally, we show that the stable restoration of miR-122 in HepG2 cells suppresses cellular proliferation and activates SB-3CT the expression of three hepatocyte functional genes, including the cholesterol-7α hydroxylase gene (CYP7A1), a known target of CUTL1 in hepatocytes. Conclusion: Our study provides a model in which miR-122 functions as an effector of LETFs and contributes to liver development by regulating the balance between proliferation and differentiation of hepatocytes, at least by targeting CUTL1. HEPATOLOGY 2010 MicroRNAs (miRNAs) are a family of small, noncoding RNAs that have emerged as posttranscriptional regulators of gene expression in animals and plants.