MicroRNAs mir‐184 and let‐7 alter Drosophila metabolism and longevity

MicroRNAs (miRNAs) are small RNA molecules that regulate gene expression associated with many complex biological processes. By comparing miRNA expression between long‐lived cohorts of Drosophila melanogaster that were fed a low‐nutrient diet with normal‐lived control animals fed a high‐nutrient diet, we identified miR‐184, let‐7, miR‐125, and miR‐100 as candidate miRNAs involved in modulating aging. We found that ubiquitous, adult‐specific overexpression of these individual miRNAs led to significant changes in fat metabolism and/or lifespan. Most impressively, adult‐specific overexpression of let‐7 in female nervous tissue increased median fly lifespan by ~22%. We provide evidence that this lifespan extension is not due to alterations in nutrient intake or to decreased insulin signaling.     

Aryl hydrocarbon‐estrogen alpha receptor‐dependent expression of miR‐206, miR‐27b,and miR‐133a suppress cell proliferation and migration in MCF‐7 cells

The underlying functions of miR‐206, miR‐133a, miR‐27b, and miR‐21, and their link to the estrogen receptor alpha (ERα) and aryl hydrocarbon receptor (AhR) signaling pathways remain largely unexplored. In this study, we detect the expression of miR‐206, miR‐133a, miR‐27b, and miR‐21 in MCF‐7 through quantificational real‐time polymerase chain reaction assay along with the activation/inhibition of ERα and AhR receptors. Aside from this, cell proliferation and migration as well as AhR‐dependent CYP1A1 enzyme activity were measured. Here, we found that the forced increased expression of miR‐206, miR‐133a, and miR‐27b were closely associated with the suppression of MCF‐7 cell proliferation and migration. The anti‐proliferative‐metastatic effect of miR‐206, miR‐133a, and miR‐27b was probably mediated by targeting the ERα and AhR signaling pathways. Considered together, our study indicated that the overexpression of miR‐206, miR‐133a, and miR‐27b might be potential biomarkers for prognosis and therapeutic strategies in breast cancer.     

Circulating miR‐145 is associated with plasma high‐sensitivity C‐reactive protein in acute ischemic stroke patients

Stroke is a major cerebrovascular disease threatening human health and life with high morbidity, disability and mortality. We aimed to find effective biomarkers for the early diagnosis on stroke. Nine previously reported stroke‐associated miRNAs (miR‐21, miR‐23a, miR‐29b, miR‐124, miR‐145, miR‐210, miR‐221, miR‐223 and miR‐483‐5p) were measured by quantitative real time‐PCR, and plasma high‐sensitivity C‐reactive protein (hs‐CRP) and serum interleukin 6 (IL‐6), the pro‐inflammation markers in brain injury, were examined by enzyme‐linked immunosorbent assay in 146 acute ischemic stroke patients and 96 healthy blood donors. We found that serum miR‐145 was significantly increased within 24 h after stroke onset and serum miR‐23a and miR‐221 were decreased in patients. Moreover, serum miR‐145 was strong positively correlated with plasma hs‐CRP and moderate positively correlated with serum IL‐6. Meanwhile, serum miR‐23a and miR‐221 were moderate negatively correlated with plasma hs‐CRP but not serum IL‐6. Importantly, the combination of hs‐CRP and serum miR‐145 gained a better sensitivity/spectivity for prediction of acute ischemia stroke (area under receiver operating characteristic curve from 0.794 to 0.896). Conclusively, our preliminary findings indicate that serum miR‐145 upregulated in acute ischemic stroke might be a new biomarker for acute ischemia stroke evaluation. Copyright © 2015 John Wiley & Sons, Ltd.     

miR‐1‐3p and miR‐206 sensitizes HGF‐induced gefitinib‐resistant human lung cancer cells through inhibition of c‐Met signalling and EMT

Hepatocyte growth factor (HGF) overexpression is an important mechanism in acquired epidermal growth factor receptor (EGFR) kinase inhibitor gefitinib resistance in lung cancers with EGFR activating mutations. MiR‐1‐3p and miR‐206 act as suppressors in lung cancer proliferation and metastasis. However, whether miR‐1‐3p and miR‐206 can overcome HGF‐induced gefitinib resistance in EGFR mutant lung cancer is not clear. In this study, we showed that miR‐1‐3p and miR‐206 restored the sensitivities of lung cancer cells PC‐9 and HCC‐827 to gefitinib in present of HGF. For the mechanisms, we demonstrated that both miR‐1‐3p and miR‐206 directly target HGF receptor c‐Met in lung cancer. Knockdown of c‐Met mimicked the effects of miR‐1‐3p and miR‐206 transfections Meanwhile, c‐Met overexpression attenuated the effects of miR‐1‐3p and miR‐206 in HGF‐induced gefitinib resistance of lung cancers. Furthermore, we showed that miR‐1‐3p and miR‐206 inhibited c‐Met downstream Akt and Erk pathway and blocked HGF‐induced epithelial‐mesenchymal transition (EMT). Finally, we demonstrated that miR‐1‐3p and miR‐206 can increase gefitinib sensitivity in xenograft mouse models in vivo. Our study for the first time indicated the new function of miR‐1‐3p and miR‐206 in overcoming HGF‐induced gefitinib resistance in EGFR mutant lung cancer cell.     

MiR‐139‐5p,miR‐940 and miR‐193a‐5p inhibit the growth of hepatocellular carcinoma by targeting SPOCK1

The study was aimed to screen out miRNAs with differential expression in hepatocellular carcinoma (HCC), and to explore the influence of the expressions of these miRNAs and their target gene on HCC cell proliferation, invasion and apoptosis. MiRNAs with differential expression in HCC were screened out by microarray analysis. The common target gene of these miRNAs (miR‐139‐5p, miR‐940 and miR‐193a‐5p) was screened out by analysing the target genes profile (acquired from Targetscan) of the three miRNAs. Expression levels of miRNAs and SPOCK1 were determined by quantitative real time polymerase chain reaction (qRT‐PCR). The target relationships were verified by dual luciferase reporter gene assay and RNA pull‐down assay. Through 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2‐H‐tetrazolium bromide,thiazolyl blue tetrazolium bromide (MTT) and transwell assays and flow cytometry, HCC cell viability, invasion and apoptosis were determined. In vivo experiment was conducted in nude mice to investigate the influence of three miRNAs on tumour growth. Down‐regulation of miR‐139‐5p, miR‐940 and miR‐193a‐5p was found in HCC. Overexpression of these miRNAs suppressed HCC cell viability and invasion, promoted apoptosis and inhibited tumour growth. SPOCK1, the common target gene of miR‐139‐5p, miR‐940 and miR‐193a‐5p, was overexpressed in HCC. SPOCK1 overexpression promoted proliferation and invasion, and restrained apoptosis of HCC cells. MiR‐139‐5p, miR‐940 and miR‐193a‐5p inhibited HCC development through targeting SPOCK1.     

MicroRNA‐503 promotes angiotensin II‐induced cardiac fibrosis by targeting Apelin‐13

Cardiac fibrosis is a major cause of heart failure. MicroRNAs (miRs) are important epigenetic regulators of cardiac function and cardiovascular diseases, including cardiac fibrosis. This study aimed to explore the role of miR‐503 and its mechanisms in regulating cardiac fibrosis. miR‐503 was found up‐regulated in the mouse LV tissues subjected to transverse aortic constriction (TAC) and in neonatal cardiac fibroblasts (CFs) cultured with Angiotension II. The role of miR‐503 in regulating CF cell proliferation and/or collagen production in mice neonatal CFs were determined using an MTT assay and RT‐PCR respectively. Forced expression of miR‐503 increased the cellular proliferation and collagen production in mice neonatal CFs. The effects were abrogated by cotransfection with AMO‐503 (a specific inhibitor of miR‐503). Injection of antagomiR‐503 elevated cardiac function and inhibited the expression of connective tissue growth factor (CTGF) and transforming growth factor (TGF)‐β in the TAC mice. Additional analysis revealed that Apelin‐13 is a direct target of miR‐503, as the overexpression of miR‐503 decreased the protein and mRNA expression levels of Apelin‐13. In the CFs with pre‐treatment of AngII, we transfected AMO‐503 into the cells treated with siRNA‐APLN. siRNA‐APLN abolished the effects of AMO‐503 on the production of collagen I and III and the expression of TGF‐β and CTGF. Furthermore, pre‐treatment of CFs with Apelin‐13 (1–100 nmol/l) inhibited angiotensin II‐mediated collagen production and activation of CTGF and TGF‐β. So we conclude that miR‐503 promotes cardiac fibrosis via miR‐503‐Apelin‐13‐TGF‐β‐CTGF‐collagen production pathway. Thus, miR‐503 is a promising therapeutic target for reducing cardiac fibrosis.     

The role of LINC00094/miR‐224‐5p (miR‐497‐5p)/Endophilin‐1 axis in Memantine mediated protective effects on blood‐brain barrier in AD microenvironment

The dysfunction of the blood‐brain barrier (BBB) is one of the main pathological features of Alzheimer's disease (AD). Memantine (MEM), an N‐methyl‐d ‐aspartate (NMDA) receptor antagonist, has been reported that been used widely for AD therapy. This study was performed to demonstrate the role of the MEM in regulating BBB permeability in AD microenvironment as well as its possible mechanisms. The present study showed that LINC00094 was dramatically increased in Abeta_1‐42‐incubated microvascular endothelial cells (ECs) of BBB model in vitro. Besides, it was decreased in MEM‐incubated ECs. Silencing LINC00094 significantly decreased BBB permeability, meanwhile up‐regulating the expression of ZO‐1, occludin and claudin‐5. Furthermore, silencing LINC00094 enhance the effect of MEM on decreasing BBB permeability in AD microenvironment. The analysis of the mechanism demonstrated that reduction of LINC00094 inhibited Endophilin‐1 expression by up‐regulating miR‐224‐4p/miR‐497‐5p, promoted the expression of ZO‐1, occludin and claudin‐5, and ultimately alleviated BBB permeability in AD microenvironment. Taken together, the present study suggests that the MEM/LINC00094/miR‐224‐5p (miR‐497‐5p)/Endophilin‐1 axis plays a crucial role in the regulation of BBB permeability in AD microenvironment. Silencing LINC00094 combined with MEM provides a novel target for the therapy of AD.