MicroRNA Targets - How to predict?

CircRNF111 Protects Against Insulin Resistance and Lipid Deposition via Regulating miR-143-3p/IGF2R Axis in Metabolic Syndrome

Abnormal expression of circRNAs (circular RNAs), a subclass of non-coding RNAs, has been documented in numerous human diseases. Herein, we explored whether circRNAs act as ceRNAs (competing endogenous RNAs) to modulate the pathological process-insulin resistance, as well as dyslipidemia of MetS (Metabolic Syndrome). The profile of circRNAs in serume of MetS and control samples was characterized by circRNA deep sequencing. We identified circRNF111 as a key downregulated circRNA involved in MetS. The decreased expression of circRNF111 in the serum samples of MetS was directly linked to excessive insulin resistance and dyslipidemia. Loss-of-function experiments showed that circRNF111 knockdown inhibited the glucose uptake and the Akt signaling pathway, meanwhile increased the deposition of triglycerides in adipogenic differentiated hADSCs (human adipose-derived stem cells). Mechanistically, circRNF111 sponged miR-143-3p and functioned via targeting miR-143-3p along with its downstream target gene IGF2R. The role along with the mechanism of circRNF111 sponging miR-143-3p in MetS was also explored in obese mice triggered by high-fat die. Therefore, our data suggest a protective role of the novel circRNA-circRNF111 in MetS progression. CircRNF111 inhibition enhances insulin resistance and lipid deposition in MetS through regulating miR-143-3p-IGF2R cascade. This provides a promising therapeutic approach for MetS.

miRPathDB: a new dictionary on microRNAs and target pathways

In the last decade, miRNAs and their regulatory mechanisms have been intensively studied and many tools for the analysis of miRNAs and their targets have been developed. We previously presented a dictionary on single miRNAs and their putative target pathways. Since then, the number of miRNAs has tripled and the knowledge on miRNAs and targets has grown substantially. This, along with changes in pathway resources such as KEGG, leads to an improved understanding of miRNAs, their target genes and related pathways. Here, we introduce the miRNA Pathway Dictionary Database (miRPathDB), freely accessible at https://mpd.bioinf.uni-sb.de/. With the database we aim to complement available target pathway web-servers by providing researchers easy access to the information which pathways are regulated by a miRNA, which miRNAs target a pathway and how specific these regulations are. The database contains a large number of miRNAs (2595 human miRNAs), different miRNA target sets (14 773 experimentally validated target genes as well as 19 281 predicted targets genes) and a broad selection of functional biochemical categories (KEGG-, WikiPathways-, BioCarta-, SMPDB-, PID-, Reactome pathways, functional categories from gene ontology (GO), protein families from Pfam and chromosomal locations totaling 12 875 categories). In addition to Homo sapiens, also Mus musculus data are stored and can be compared to human target pathways.

MiR-154 directly suppresses DKK2 to activate Wnt signaling pathway and enhance activation of cardiac fibroblasts

Excessive proliferation of cardiac fibroblasts (CFs) and their transdifferentiation into myofibroblasts leads to expression of α-smooth muscle actin (α-SMA), as well as excessive synthesis and secretion of collagens. This process represents an important pathological basis for myocardial fibrosis (MF). MicroRNA (miR)-154 and the Wnt signaling pathway play key roles in the above process, although their specific interactions are poorly understood. After transfecting CFs with miR-154 mimics or inhibitors, miR-154 was found to inhibit the expression of Dickkopf-related protein 2 (DKK2), while miR-154 inhibitors upregulated DKK2 expression in a Western blot analysis. In a subsequent dual-luciferase activity assay, direct binding of miR-154 to DKK2 was detected. Further experiments demonstrated that transfection of DKK2 siRNA or miR-154 resulted in increased levels of β-catenin, α-SMA, and collagens I and III. Moreover, these changes were observed in association with increases in CF proliferation and migration, and reduced apoptosis. Conversely, transfection of miR-154 inhibitors or DKK2 overexpression vector resulted in lower expression levels of β-catenin, α-SMA, and collagens I and III, suppressed cell proliferation and migration, and enhanced apoptosis. Furthermore, in each assay, when the DKK2 overexpression vector and miR-154 mimics were co-transfected, the functions of each component were counteracted by the other. Therefore, in CFs, targeting of DKK2 by miR-154 leads to upregulation of β-catenin expression and activation of the classical Wnt signaling pathway and CFs. These results suggest new targets for the clinical treatment of MF and ischemic heart disease.

Relationship between mir-21 expression and clinical and pathological features of esophageal squamous cell carcinoma

AIM: To investigate mir-21 expression in esophageal squamous cell carcinoma (ESCC) and to analyze its relationship with the clinical and pathological features of ESCC.

METHODS: Real-time RT-PCR and the 2-∆∆CT method were used to detect the expression of mir-21 in 96 cases of ESCC and tumor-adjacent tissue. The relationship between expression of mir-21 and clinical and pathological features of ESCC was analyzed.

RESULTS: Of 96 cases of ESCC specimens, mir-21 was highly expressed in 40 cases (41.6%). High mir-21 expression was closely related with the degree of tumor differentiation and TNM stage (both P < 0.05).

CONCLUSION: The high expression of mir-21 may play an important role in the occurrence and development of ESCC.