Emodin regulates microRNA expressions of ileum in sepsis mice model

Objective To investigate the regulation of emodin on microRNA expressions in mouse model with sepsis by GeneChip microRNA array. Methods Forty two c57 mice were randomly (random number) divided into 3 groups: sham operation group (sham group, n=14),sepsis group(n=14) and emodin group (n=14). The sepsis model of the mouse was subjected to cecal ligation and puncture (CLP). Mice in emodin group received intraperitoneal injection of emodin (40 mg/kg) half an hour before operation and every 12 hours after CLP. All mice were sacrificed 48 h after surgery and part of the ileum were removed for intestine tissue stained with hematoxylin eosin. The levels of tumor necrosis factor-α(TNF-α), interleukin-6 (IL-6) and intestinal fatty acid binding protein (I-FABP) in peripheral blood were measured by enzyme-linked immunosorbent assay (ELISA). Total RNA of ileum tissues was extracted from the sepsis group and emodin group, and then subjected to miRNA microarray. The results of microarray were further verified by quantitative real-time PCR (qRT-PCR). Target genes of differentially expressed miRNAs were predicted and subjected to gene ontology (GO) and KEGG pathway enrichment analysis. Data of multi-groups were analyzed by one way variance (ANOVA) and inter-group comparisons were made by SNK-q tests. Mann-Whitney U test was used when homogeneity of variance were not met. The value of P<0.05 was considered statistically significant. Results Compared to the sepsis group, the levels of serum TNF-α, IL-6 and I-FABP in the emodin group were decreased significantly. MiRNA microarray showed that 23 miRNAs were differentially expressed in the emodin group as compared to the sepsis group, among which 17 miRNAs were up-regulated and 6 miRNAs were down-regulated. qRT-PCR results were consistent with miRNA array data. Target genes of 10 selected miRNAs were predicted and subjected to bioinformatic analysis. A total of 3 410 target genes were significantly enriched in 2 072 GO biological process terms, 246 GO cellular component items and 277 GO molecular function terms. Moreover, KEGG pathway analysis showed that these differential miRNAs were involved in the regulation of PI3K-Akt signaling pathway, MAPK signaling pathway, and TNF signaling pathway. Conclusions Emodin can regulate the expression of multiple microRNAs, and play an important role in protecting the intestinal mucosal barrier via a variety of targets and pathways. Key words: Emodin; Sepsis; Intestinal mucosa; MicroRNA; Expression profiles; Bioinformatics