Gene array analysis was performed according to the manufacturer’s instructions (GeneChip 430 2.0 and 230 2.0; Affymetrix, Santa Clara, CA), followed by data analysis as described.9 Primers for quantitative polymerase chain reaction (qPCR) validation of array PI3K inhibitor analysis are summarized in Supporting Table 1. Further description of Materials and Methods is included within the supporting data set (Supporting Materials and Methods) In a systematic approach to identify miRNAs involved in liver fibrosis, we applied the well-established model of carbon tetrachloride (CCl4) treatment for hepatic fibrogenesis in mice (Supporting Fig.

1A-C). We compared miRNA expression profiles in fibrotic livers from mice treated for 6 weeks with CCl4 to expression profiles in livers from control mice by performing microarray analysis on INCB024360 purchase RNA extracts from these

livers. MicroRNAs were considered as differentially expressed when differences in expression levels were significant both in unpaired Student t test (P < 0.01) and significance analysis of microarray test (q value <5%). Among the individual miRNAs represented on the microarray, 31 miRNAs were differentially regulated on induction of liver fibrosis (Fig. 1A). As shown in Fig. 1B, 10 miRNAs were significantly overexpressed in fibrotic livers, whereas 21 miRNAs showed a significantly lower expression when compared with control animals. The regulation of exemplary miRNAs identified in the array analysis was confirmed by qPCR. As shown in Fig. 1C, up-regulation of miRNAs miR-125-5p, miR-199b*, miR-221, and miR-302c as well as down-regulation of miR-29 family members could be confirmed in this analysis. Thus, by applying a systematic array

approach, we identified subsets of miRNAs that are differentially regulated during CCl4-induced liver fibrosis. Among the miRNAs that were shown to be differentially medchemexpress regulated during hepatic fibrogenesis, miR-29 family members showed a striking relationship to numerous genes encoding for collagen and other extracellular matrix proteins on an in-silico analysis on potential targets (Supporting Table 3). After 6 and 8 weeks of CCl4 treatment, all miR-29 members were significantly down-regulated (Fig. 2A). Although down-regulation appeared most prominent for miR-29b, no significant differences between the individual members of the miR-29-family were detectable (Fig. 2A; data not shown). These results in Balb/c-mice were confirmed in mice with a C57BL/6 background (Fig. 2B; Supporting Fig. S2A, B). Interestingly, decreased expression of miR-29b in these animals was significantly correlated with the degree of liver fibrosis as determined by hydroxyproline assay (Fig. 2C). Furthermore, we measured expression of these miRNAs at 21 days after bile duct ligation as an additional model for liver fibrosis in mice. As seen in Fig.