Direct Target Of miR-124 Research Articles

MicroRNA-210-mediated proliferation, survival, and angiogenesis promote cardiac repair post myocardial infarction in rodents.

MiRNA-210 transfected adult rat CMs show proliferation and reduced cell death in vitro. Cell cycle inhibitor APC is a target of miR-210. MiR-210 overexpressing (210-TG) mouse hearts show CMs cell cycle re-entry and survival post myocardial injury. 210-TG mice show significant neovascularization and angiogenic potential post myocardial infarction. 210-TG hearts show reduced infarct size following ischemic injury.

Long non-coding RNA SeT and miR-155 regulate the Tnfα gene allelic expression profile.

It is becoming increasingly appreciated that the non-coding genome may have a great impact on the regulation of chromatin structure and gene expression. The innate immune response can be mediated upon lipopolysaccharide stimulation of macrophages which leads to immediate transcriptional activation of early responsive genes including tumor necrosis factor alpha (Tnfα). The functional role of non-coding RNAs, such as lncRNAs and microRNAs, on the transcriptional activation of proinflammatory genes and the subsequent regulation of the innate immune response is still lacking mechanistic insights. In this study we wanted to unravel the functional role of the lncRNA SeT, which is encoded from the murine Tnfα gene locus, and miR-155 on the transcriptional regulation of the Tnfα gene. We utilized genetically modified mice harboring either a deletion of the SeT promoter elements or the mature miR-155 and studied the response of macrophages to lipopolysaccharide (LPS) stimulation. We found that decreased expression of the lncRNA SeT in murine primary macrophages resulted in increased mortality of mice challenged with LPS, which was corroborated by increased Tnfα steady state mRNA levels and a higher frequency of biallelically expressing macrophages. On the contrary, miR-155 deletion resulted in reduced Tnfα mRNA levels supported by a lower frequency of biallelically expressing macrophages upon stimulation with LPS. In both cases, in the absence of either lncRNA SeT or miR-155 we observed a deregulation of the Tnfα allele homologous pairing, previously shown to regulate the switch from mono- to bi-allelic gene expression. Although lncRNA SeT was not found to be a direct target of miR-155 its stability was increased upon miR-155 deletion. This study suggests a role of the non-coding genome in mediating Tnfα mRNA dosage control based on the regulation of homologous pairing of gene alleles and their subsequent biallelic expression.

MicroRNA-145 suppresses esophageal squamous cell carcinoma by targeting phospholipase C epsilon 1

Objective To investigate the mechanism of microRNA (miRNA, miR)-145 in modulating the capacity of proliferation and invasion in esophageal squamous cell carcinoma (ESCC). Methods Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) was used to detect the expression of miR-145 and phospholipase C epsilon 1 (PLCE1) mRNA. PLCE1 protein level was evaluated by Western blotting. The potential target gene of miR-145 was predicted by targetscan software. Luciferase reporter gene assay was used to validate the predicted miR-145 binding site in PLCE1 3’untranslated region (3’UTR). Proliferation and invasion capacity were assessed by MTT and wound healing assay separately. Results The relative expression of miR-145 in four types of ESCC cells were 0.63±0.06, 0.72±0.05, 0.55±0.05 and 0.79±0.04 separately, which were obviously lower than in normal esophageal epithilum (P=0.000, P=0.001, P=0.000, P=0.003). While, relative expression of miR-145 in ESCC tissues was 0.68±0.03, which was 31.9% lower than in normal esophageal tissue (P=0.000). An inverse correlation between miR-145 expression and tumor invasion depth and TNM stage were observed (χ2=8.380, P=0.039; χ2=6.810, P=0.033). Luciferase reporter gene assay proved that PLCE1 was a direct target of miR-145. PLCE1 was overexpressed and inversely correlated with miR-145 expression in ESCC (r=-0.828, P=0.002). The relative expression of PLCE1 in four types of ESCC cells were 1.69±0.04, 1.46±0.06, 1.31±0.06 and 1.60±0.08, which were obviously higher than in normal esophageal epithilum (P=0.000, P=0.000, P=0.004, P=0.001). And relative PLCE1 expression was 1.85±0.04 in ESCC tissues, which was 1.85 times higher than in normal esophageal tissue (P=0.000). In addition, overexpression of miR-145 suppressed Eca109 cells proliferation (P=0.006) and decreased invasion capacity by 22.1% (P=0.013). Whereas, overexpression of PLCE1 induced proliferation (P=0.003) and elevated invasion capacity by 24.9% (P=0.029). Enforced expression of miR-145 could partially reversed the promoting effect of PLCE1 (P=0.003). Conclusion MiR-145 suppresses proliferation and invasion of ESCC by targeting PLCE1. Key words: MicroRNA-145; Phospholipase C epsilon 1; Esophageal neoplasms; Proliferation; Invasion

MicroRNA-210 alleviates oxidative stress-associated cardiomyocyte apoptosis by regulating BNIP3.

Oxidative stress-induced myocardial apoptosis and necrosis are involved in ischemia/reperfusion (I/R) injury. This study was performed to investigate microRNA (miR)-210's role in oxidative stress-related myocardial damage. The expression of miR-210 was upregulated in myocardial tissues of I/R rats, while that of Bcl-2 adenovirus E1B 19kDa-interacting protein 3 (BNIP3) was downregulated. To simulate in vivo oxidative stress, H9c2 cells were treated with H2O2 for 48h. MiR-210 level was increased upon H2O2 stimulation, peaked at 8h, and then decreased. An opposite expression pattern of BNIP3 was observed. BNIP3 was demonstrated as a direct target of miR-210 via luciferase reporter assay. H2O2-induced cell apoptosis was attenuated by miR-210 mimics, whereas aggravated by miR-210 inhibitor. MiR-210 knockdown-induced cell apoptosis in presence of H2O2 was attenuated by BNIP3 siRNA. Our work demonstrates that miR-210 plays a protective role in H2O2-induced cardiomyocyte apoptosis at least by regulating the pro-apoptotic BNIP3.

Abstract P268: Overexpression of miR-210 Induces Preeclampsia-like Symptoms in Pregnant Mice by Attenuating the STAT6/IL-4 Pathway

Preeclampsia (PE) is a pregnancy-related hypertensive disorder that affects 5-8% of all pregnancies worldwide. Placental microRNA (miRNA) expression is known to be dysregulated during PE which includes miR-210. However, the role of miR-210 in the development of PE is still unknown. We have previously demonstrated STAT6, a transcription factor, to be a direct target of miR-210. In addition, STAT6 modulates levels of IL-4, an anti-inflammatory cytokine which is known to be beneficial during pregnancy. Given that the STAT6/IL-4 pathway is important for normal pregnancy, we hypothesized that an overexpression of miR-210 in mice will contribute to PE-like symptoms by inhibiting the STAT6/IL-4 pathway. Systolic blood pressures (SBP) were measured using the tail-cuff method on both WT (C57Bl/6J) and miR-210 TG mice. The miR-210 TG mice exhibited increased SBP compared to the WT mice (WT: 95±2 mmHg, miR-210 TG: 115±2.4 mmHg, p<0.05). The miR-210 TG mice also displayed endothelial dysfunction measured by aortic vascular reactivity using wire myography (WT: 93% miR-210 TG: 68% relaxation, p<0.05 vs. WT) and a significant increase in proteinuria (4 fold, p<0.05 vs. WT). Furthermore, the miR-210 TG mice exhibit placental necrosis and a significant increase in the number of malformed pups. Placental STAT6 levels decreased in miR-210 TG compared to WT mice (2.6 fold, p<0.05 vs. WT) as determined by immunoblotting. In addition, qRT-PCR analysis of the miR-210 TG placentas exhibited a (4.8 fold, p<0.05 vs. WT) decrease in IL-4 expression. Immunoblotting and immunohistochemistry (IHC) studies showed a decrease in IL-4 levels (2.4 fold, p<0.05 vs. WT) and immunoreactivity in the miR-210 TG placentas as well as. IHC studies in human placentas also showed a decrease in both IL-4 and STAT6. Based on our results, miR-210 overexpression induces PE-like symptoms including hypertension, endothelial dysfunction, proteinuria, and malformed pups in pregnant mice. In addition, miR-210 overexpression attenuated the STAT6/IL-4 anti-inflammatory pathway. Our data suggests that either targeting miR-210 or the STAT6/1L-4 pathway could be a potential therapeutic in mitigating the symptoms of PE.

Role of MicroRNA-93 I in Pathogenesis of Left Ventricular Remodeling via Targeting Cyclin-D1.

BackgroundThe objective of this study was to identify the pathway responsible for ventricular remodeling.Material/MethodsWe collected remodeling myocardium tissue (n=18) and control myocardium tissue (n=22), and detected the expression of 4 miRNAs in these 2 groups using real-time PCR. We then searched the miRNA database online to find the candidate genes of miR-93. Real-time PCR and Western blot analysis were used to confirm the regulatory relationship.ResultsWe found that only miR-93 was decreased in remodeling myocardium tissue, and validated CCND1 to be the direct target gene of miR-93, with the “seed sequence” located within the 3′-UTR of the target gene via luciferase reporter assay system. Furthermore, we established the negative regulatory relationship between miR-93 and CCND1 by determining the relative luciferase activity of cells transfected with wild-type or mutant 3′-UTR of CCND1. We also found that The CCND1 protein and mRNA expression level of HL-1 cells treated with 50 nM miR-93 mimics were apparently lower than the scramble control, and those of the cells treated with 100 nM miR-93 mimics and CCND1 siRNA (100 nM) were even lower than those in the 50 nM treatment group. Meanwhile, cells transfected with miR-93 mimics (50 nM) showed evidently downregulated viability when compared with the scramble controls, while cells transfected with (100 nM) and CCND1 siRNA (100nM) showed even lower viability.ConclusionsWe showed that CCND1 is a direct target of miR-93, and the dysregulation of the miR-93/CCND1 signaling pathway is responsible for the development of ventricular remodeling.

A Novel MicroRNA-124/PTPN1 Signal Pathway Mediates Synaptic and Memory Deficits in Alzheimer’s Disease

BackgroundSynaptic loss is an early pathological event in Alzheimer’s disease (AD), but its underlying molecular mechanisms remain largely unknown. Recently, microRNAs (miRNAs) have emerged as important modulators of synaptic function and memory. MethodsWe used miRNA array and quantitative polymerase chain reaction to examine the alteration of miRNAs in AD mice and patients as well as the Morris water maze to evaluate learning and memory in the mice. We also used adeno-associated virus or lentivirus to introduce tyrosine-protein phosphatase non-receptor type 1 (PTPN1) expression of silencing RNAs. Long-term potentiation and Golgi staining were used to evaluate the synaptic function and structure. We designed a peptide to interrupt miR-124/PTPN1 interaction. ResultsHere we report that neuronal miR-124 is dramatically increased in the hippocampus of Tg2576 mice, a recognized AD mouse model. Similar changes were observed in specific brain regions of affected AD individuals. We further identified PTPN1 as a direct target of miR-124. Overexpression of miR-124 or knockdown of PTPN1 recapitulated AD-like phenotypes in mice, including deficits in synaptic transmission and plasticity as well as memory by impairing the glutamate receptor 2 membrane insertion. Most importantly, rebuilding the miR-124/PTPN1 pathway by suppression of miR-124, overexpression of PTPN1, or application of a peptide that disrupts the miR-124/PTPN1 interaction could restore synaptic failure and memory deficits. ConclusionsTaken together, these results identified the miR-124/PTPN1 pathway as a critical mediator of synaptic dysfunction and memory loss in AD, and the miR-124/PTPN1 pathway could be considered as a promising novel therapeutic target for AD patients.

MicroRNA-143 and -145 modulate the phenotype of synovial fibroblasts in rheumatoid arthritis

Fibroblast-like synoviocytes (FLSs) constitute a major cell subset of rheumatoid arthritis (RA) synovia. Dysregulation of microRNAs (miRNAs) has been implicated in activation and proliferation of RA-FLSs. However, the functional association of various miRNAs with their targets that are characteristic of the RA-FLS phenotype has not been globally elucidated. In this study, we performed microarray analyses of miRNAs and mRNAs in RA-FLSs and osteoarthritis FLSs (OA-FLSs), simultaneously, to validate how dysregulated miRNAs may be associated with the RA-FLS phenotype. Global miRNA profiling revealed that miR-143 and miR-145 were differentially upregulated in RA-FLSs compared to OA-FLSs. miR-143 and miR-145 were highly expressed in independent RA-FLSs. The miRNA-target prediction and network model of the predicted targets identified insulin-like growth factor binding protein 5 (IGFBP5) and semaphorin 3A (SEMA3A) as potential target genes downregulated by miR-143 and miR-145, respectively. IGFBP5 level was inversely correlated with miR-143 expression, and its deficiency rendered RA-FLSs more sensitive to TNFα stimulation, promoting IL-6 production and NF-κB activity. Moreover, SEMA3A was a direct target of miR-145, as determined by a luciferase reporter assay, antagonizing VEGF165-induced increases in the survival, migration and invasion of RA-FLSs. Taken together, our data suggest that enhanced expression of miR-143 and miR-145 renders RA-FLSs susceptible to TNFα and VEGF165 stimuli by downregulating IGFBP5 and SEMA3A, respectively, and that these miRNAs could be therapeutic targets.

MiR-203 inhibits estrogen-induced viability, migration and invasion of estrogen receptor α-positive breast cancer cells.

Breast cancer is common in females, and accounts for a large proportion of cancer-related cases of mortality. MicroRNAs (miRs) have been found to be involved in the progression of breast cancer via mediation of tumor suppressor genes or oncogenes. Previously, miR-203 has been reported to play a suppressive role in breast cancer. In the present study, the effects of miR-203 on the malignant phenotypes of estrogen receptor α (ERα)-positive breast cancer cells were investigated. It was found that treatment with estradiol (E2) significantly enhanced the viability, migration and invasion of ERα-positive breast cancer MCF-7 cells, accompanied by the significant downregulation of miR-203 in a dose-dependent manner. Furthermore, MCF-7 cells were transfected with miR-203 mimics, resulting in a significant increase in miR-203 levels. Upregulation of miR-203 was found to significantly inhibit E2-induced upregulation of MCF-7 cell viability, migration and invasion. Upregulation of miR-203 also led to a significant decrease in the protein expression of ERα in MCF-7 cells. Using a luciferase reporter assay, ERα was identified as a direct target of miR-203 in MCF-7 cells. Finally, it was demonstrated that miR-203 was significantly downregulated in ERα-positive breast cancer tissues compared to their matched normal adjacent tissues. The expression levels of miR-203 were inversely correlated to the ERα levels in ERα-positive breast cancer tissues. Based on these results, it is proposed that miR-203 inhibits E2-induced viability, migration and invasion of ERα-positive breast cancer cells, and that this may be via direct targeting of ERα. Therefore, the present study highlights the importance of miR-203 and ERα in breast cancer progression.

Inhibition of autophagy potentiates the proliferation inhibition activity of microRNA-7 in human hepatocellular carcinoma cells

MicroRNAs (miRNAs/miRs) are important molecules that are able to regulate multiple cellular processes in cancer cells. miR-7 has been previously identified as a tumor suppressive miRNA in several types of cancer. The aim of the present study was to investigate whether miR-7 is able to regulate autophagy in hepatocellular carcinoma (HCC) cells. It was identified that miR-7 was significantly downregulated in tumor tissues compared with adjacent normal tissues. Overexpression of miR-7 inhibited cell proliferative activity, which was partially reversed by miR-7 inhibitor. In addition, overexpression of miR-7 significantly induced an increasen in autophagic activity, and luciferase activity assay and western blot analysis identified that mammalian target of rapamycin (mTOR) was a direct target of miR-7. In addition, inhibition of autophagy by 3-methyladenine resulted in a marked enhancement of the proliferation inhibition effect of miR-7. In conclusion, miR-7 was identified to induce proliferation inhibition and autophagy in HCC cells by targeting mTOR, and inhibition of autophagy may be utilized to enhance the antitumor activity of miR-7.

MiR-107 Promotes Proliferation and Inhibits Apoptosis of Colon Cancer Cells by Targeting Prostate Apoptosis Response-4 (Par4).

Colorectal cancer (CRC) is one of the most common malignancies in the world, with a high incidence and a high mortality. However, the pathogenesis of CRC carcinogenesis is still unexplored. In this study, we investigated the role of miR-107 in the regulation of CRC cell proliferation and apoptosis. First, the expression of miR-107 was observed to be aberrantly increased in human CRC tumor tissues and cell lines when compared to the colonic control tissues and colon epithelial cells. Further study showed that the proliferative and apoptotic capacities of human CRC SW480 and LoVo cells were aberrantly regulated by miR-107. The proliferation of SW480 and LoVo cells was remarkably enhanced by the miR-107 mimic but suppressed by the miR-107 inhibitor when compared to the negative control. On the contrary, the apoptotic rate of both SW480 and LoVo cells was significantly inhibited by miR-107 overexpression but increased by miR-107 inhibition. In addition, we identified prostate apoptosis response-4 (Par4) as a direct target of miR-107 with a potential binding site on the 3′-UTR of mRNA, as evaluated by bioinformatics prediction and luciferase reporter assay. Par4 expression levels were significantly inhibited by the miR-107 mimic but upregulated by the miR-107 inhibitor in both SW480 and LoVo cells. Compared to the control, the increase in Par4 expression significantly inhibited the induction role of miR-107 in the proliferation of SW480 and LoVo cells, and the apoptotic rate of cells repressed by the miR-107 mimic was also reversed by Par4 overexpression. In summary, our results demonstrated that miR-107 exerts a positive role in the survival of CRC cells by directly targeting Par4. This might reveal a novel understanding about human CRC pathogenesis.

MiR-210 facilitates ECM degradation by suppressing autophagy via silencing of ATG7 in human degenerated NP cells

Intervertebral disc degeneration (IDD) is thought to be the most common cause of low back pain. Dysregulation of microRNAs (miRNAs) is involved in the development of IDD. The aim of this study was to explore the influence of miR-210 on type II collagen (Col II) and aggrecan expression and possible mechanisms in human degenerated nucleus pulposus (NP) cells. Our results showed that miR-210 levels were significantly increased in degenerated NP tissues compared with healthy controls, and positively correlated with disc degeneration grade. By gain-of-function and loss-of-function studies in human degenerated NP cells, miR-210 was shown to inhibit autophagy and then upregulate MMP-3 and MMP-13 expression, leading to increased degradation of Col II and aggrecan. Autophagy-related gene 7 (ATG7) was identified as a direct target of miR-210. Knockdown of ATG7 by small interfering RNA (siRNA) abrogated the effects of miR-210 inhibitor on MMP-3, MMP-13, Col II and aggrecan expression. Taken together, these results suggest that miR-210 inhibits autophagy via silencing of ATG7, leading to increased Col II and aggrecan degradation in human degenerated NP cells.

MicroRNA-150 functions as an antioncogenic regulator in osteosarcoma.

Numerous studies have demonstrated that microRNAs (miRs) are involved in several physiological and pathological processes, and participate in cancer initiation and progression. The abnormal expression of miR-150 has been reported in numerous types of human cancer. However, at present there are no studies of miR-150 in osteosarcoma (OS). Reverse transcription-quantitative polymerase chain reaction was performed to measure miR-150 expression levels in OS tissues and cell lines. Subsequent to transfection with miR-150 mimics or zinc finger E-box binding homeobox 1 (ZEB1) small interfering RNA, an MTT assay, Transwell migration and invasion assays, western blotting and a Dual-Luciferase reporter assay were performed in human OS cell lines. The present study revealed that miR-150 was downregulated in OS tissues and cell lines. In addition, the expression levels of miR-150 were correlated with the clinical stage and degree of distant metastasis of patients with OS. In addition, ZEB1 was identified as a direct target of miR-150 in vitro. In conclusion, miR-150 targeted ZEB1 to function as an antioncogenic regulator in OS. These findings elucidated a novel underlying mechanism for the pathogenic process in OS carcinogenesis and progression, and may provide novel targeted therapeutic regimens for patients with OS.

Long non-coding RNA PVT1 promotes glycolysis and tumor progression by regulating miR-497/HK2 axis in osteosarcoma

Cancer cells usually utilize glucose as a carbon source for aerobic glycolysis, a phenomenon known as the Warburg effect. Increasing studies have shown that PVT1 (a long non-coding RNA, lncRNA) functions as critical regulator of multiple cancers. However, it remains totally unknown whether and how PVT1 regulates glucose metabolism in OS cells. In this study, we found that the expression of PVT1 were specifically increased in OS cells and tissues, and the upregulated PVT1 indicated poor prognosis. Glucose uptake, lactate production, and the expression of HK2 in OS cells were increased by overexpression of PVT1, while decreased by PVT1 knockdown. We further fund that PVT1 acted as molecular sponge to repress miR-497. Inhibition of miR-497 promoted glucose consumption and lactate production, phenomenon could be reversed by PVT1 silencing. Moreover, HK2 was a direct target of miR-497 and overexpression of HK2 attenuated the suppressive effect of miR-497 on glycolysis. Functionally, knockdown of PVT1 exerted tumor-suppressive effect by suppressing cell proliferation, cell cycle progression, and invasion in vitro, whereas miR-497 inhibitor partially abolished the inhibition effect of si-PVT1. Overexpression of HK2 attenuated the miR-497 induced inhibition of cell growth and motility. Taken together, these findings suggested that PVT1 contributes to OS cell glucose metabolism, cell proliferation, and motility through the miR-497/HK2 pathway, and revealed a novel relation between lncRNA and the alteration of glycolysis in OS cells.

MiR-203 Interplays with Polycomb Repressive Complexes to Regulate the Proliferation of Neural Stem/Progenitor Cells.

SummaryThe polycomb repressive complexes 1 (PRC1) and 2 (PRC2) are two distinct polycomb group (PcG) proteins that maintain the stable silencing of specific sets of genes through chromatin modifications. Although the PRC2 component EZH2 has been known as an epigenetic regulator in promoting the proliferation of neural stem/progenitor cells (NSPCs), the regulatory network that controls this process remains largely unknown. Here we show that miR-203 is repressed by EZH2 in both embryonic and adult NSPCs. MiR-203 negatively regulates the proliferation of NSPCs. One of PRC1 components, Bmi1, is a downstream target of miR-203 in NSPCs. Conditional knockout of Ezh2 results in decreased proliferation ability of both embryonic and adult NSPCs. Meanwhile, ectopic overexpression of BMI1 rescues the proliferation defects exhibited by miR-203 overexpression or EZH2 deficiency in NSPCs. Therefore, this study provides evidence for coordinated function of the EZH2-miR-203-BMI1 regulatory axis that regulates the proliferation of NSPCs.

MicroRNA-145 Negatively Regulates Cell Proliferation Through Targeting IRS1 in Isolated Ovarian Granulosa Cells From Patients With Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) is a complex, heterogeneous endocrine and metabolic disorder affecting 5% to 10% of reproductive-age women. A high rate of granulosa cell (GC) proliferation contributes to the abnormal folliculogenesis in patients with PCOS. Evidence has proved that dysregulation of microRNAs is involved in the pathogenesis of PCOS. In this study, we investigated the effect of miR-145 on cell proliferation and the underlying mechanism of miR-145 in isolated human GCs from the aspirated follicular fluid in women with PCOS. Our findings showed that miR-145 is downregulated in human GCs from PCOS. The miR-145 mimics suppress cell proliferation and promoted cell apoptosis in human GCs from PCOS. However, miR-145 inhibitor promotes cell proliferation and inhibited cell apoptosis. Moreover, using a dual-luciferase reporter assay, we confirmed that the insulin receptor substrate 1 (IRS1) gene is a direct target of miR-145. The miR-145 mimics inhibited messenger RNA and protein IRS1 expression levels, and silencing of IRS1 by small interfering RNA inhibits human GC proliferation, but IRS1 overexpression abrogates the suppressive effect of miR-145 mimics. Furthermore, miR-145 mimics can inhibit the activation of p38 mitogen-activated protein kinase (p38 MAPK) and extracellular signal-regulated kinase (ERK). The IRS1 overexpression abrogates the suppressive effect of miR-145 mimics on MAPK/ERK signaling pathways. Together, miR-145 mimics suppress cell proliferation by targeting and inhibiting IRS1 expression to inhibit MAPK/ERK signaling pathways. Our study further found that high concentrations of insulin decreases the miR-145 expression, upregulates IRS1, and promotes cell proliferation. These observations showed that miR-145 is a novel and promising molecular target for improving the dysfunction of GCs in PCOS.

MicroRNA-222 regulates proliferation and apoptosis of fibroblasts in hypertrophic scar via matrix metalloproteinase 1

Objective: To explore the effect of microRNA(miR)-222 on cell proliferation and apoptosis of fibroblasts in hypertrophic scar (HS) and the underlying mechanisms. Methods: The expression of miR-222 in the HS and the normal skin tissues was detected by real-time RT-PCR. The HS fibroblasts were transfected with miR-222 mimic and miR-222 inhibitor respectively. The cell viability was tested with MTT assay, cell cycle distribution and apoptosis were detected with flow cytometry and the expression levels of proliferation, apoptosis and cell cycle related proteins were determined with Western blot. Direct target of miR-222 was evaluated by dual-luciferase reporter assay. Results: miR-222 was significantly up-regulated in HS tissues compared with normal skin tissues(P<0.05). Overexpression of miR-222 enhanced the cell viability of HS fibroblasts; increased mRNA and protein expressions of proliferating cell nuclear antigen (PCNA), collagen alpha-1 (Ⅰ) chain (Col1A1) and collagen alpha-1 (Ⅲ) chain (Col3A1); increased cell population in S phase and protein expressions of cyclin D1, cyclin E1 and cyclin-dependent kinases 1 (CDK1); inhibited cell apoptosis and reduced protein expressions of caspase-3/9. Overexpression of MMP1 attenuated the effects of miR-222 on the cell viability and apoptosis in fibroblasts, reduced expression levels of PCNA, cyclin D1 and the expression of caspase-3 was increased. Conclusion: miR-222 enhances cell proliferation and inhibits cell apoptosis of HS fibroblasts through negative regulation of MMP1, which suggests that miR-222 and MMP1 might be used as novel biomarkers and targets in diagnostic and therapeutic approaches for HS.

MiR-155 contributes to Th17 cells differentiation in dextran sulfate sodium (DSS)-induced colitis mice via Jarid2

MicroRNAs (miRNAs) play an important role in regulating immune system function by mRNA destabilisation or inhibition of translation. Recently, miR-155 was detected to be significantly up-regulated in colonic tissues of patients with active UC. However, it is unknown whether miR-155 is involved in the pathogenesis of UC and how it influences immune response in dextran sulfate sodium (DSS)-induced colitis mice. Here, we investigated the role of miR-155 in UC. Firstly, through bioinformatics analysis and luciferase report assay, we found Jarid2 was a direct target of miR-155; then, we carried out in situ hybridization, immunofluorescence and flow cytometry, and revealed that miR-155 levels were increased, Jarid2 levels were decreased and the frequency of Th17 cells was elevated in DSS-induced mice; we also used lentiviral vector to deliver miR-155 inhibition sequences to silence miR-155 that was effectively taken up by epithelial cells. MiR-155 inhibition attenuated DSS-induced colonic damage and inhibited Th17 cells differentiation. This study suggests that miR-155 plays a host-damaging role during DSS-induced colitis mice and induces Th17 differentiation by targeting Jarid2.

The SNAIL/miR-128 axis regulated growth, invasion, metastasis, and epithelial-to-mesenchymal transition of gastric cancer.

miR-128 is expressed in various tumors, but its expression and function in gastric cancer have not been defined. Thus, the goal of this study was to characterize miR-128 in gastric cancer. We found first that miR-128 is down-regulated in gastric cancer cell lines and tissues, and this dysregulation is correlated with DNA methylation and the transcription factor SNAIL. Using prediction tools, western blotting, and luciferase reporter assays, we found that Bmi-1 was the direct target of miR-128. Additionally, overexpression of miR-128 inhibited gastric cancer cell migration, invasion, and proliferation by targeting Bmi-1 in vitro and in vivo. We also documented, with receiver operating characteristic curves and Kaplan-Meier survival analysis, that miR-128 and Bmi-1 may be useful markers for diagnosing and estimating the prognosis of gastric cancer patients. As the epithelial-to-mesenchymal transition is an important mechanism associated with cancer invasion and metastasis, we inferred that miR-128 could regulate this mechanism in gastric cancer. In fact, we found that miR-128 could reverse epithelial-to-mesenchymal transition induced by Bmi-1 via the PI3K/AKT pathway. Because SNAIL also acts as a mesenchymal marker, our findings identified a novel positive feedback loop in which the transcription factor SNAIL curbs the expression of miR-128, and then down-regulated miR-128 promotes the expression of Bmi-1; finally, overexpression of Bmi-1 drives the epithelial-to-mesenchymal transition process via the PI3K/AKT pathway, and the expression of SNAIL is up-regulated.

MiR-107 functions as a tumor suppressor in human esophageal squamous cell carcinoma and targets Cdc42.

Previously, we reported significantly decreased expression of tissue and circulating miR-107 in esophageal cancer (EC). However, its role in esophageal tumorigenesis still remains elusive. Therefore, the aim of the present study was to analyze the role of miR-107 in esophageal squamous cell carcinoma (ESCC). The role of miR-107 in ESCC was evaluated using MTT assay, cell cycle analysis by flow cytometry, annexin assay, colony formation assay and scratch assay. Overexpression of miR-107 in KYSE-410 cells suppressed cell proliferation at 72h post-transfection (p=0.0001). Moreover, a significant increase in the G0/G1 population (p<0.001) and a significant decrease in the G2/M (p=0.032) population was also observed in the miR-107-treated cells as compared to the negative control (NC). Notably, miR-107 overexpression attenuated the colony formation potential of ESCC cells by 41.83% as compared to the NC (p=0.007). miR-107 mimic inhibited ESCC cell migration in a time-dependent manner, reducing the wound closure to only 50.41±7.23% at 72h post-transfection (p=0.041). Further analysis by Matrigel invasion assay revealed a significant decrease in the migratory and invasive abilities of the KYSE-410 cells at 72h post miR-107 transfection. qRT-PCR analysis showed decreased expression of one of the newly identified targets of miR-107, Cdc42, at the mRNA level. Further validation by western blotting confirmed a significant reduction in the identified target at the protein level. In addition, the relative luciferase activity of the reporter containing Cdc42 3'UTR was significantly decreased upon miR-107 co-transfection, indicating it to be a direct target of miR-107. Our results herein document that miR-107 functions as a tumor suppressor and inhibits the proliferation, migration and invasion of ESCC cells. Moreover, this is the first report showing Cdc42 as a downstream target of miR-107.