105,935 research outputs found
miR-532/miR-3064 overexpression inhibits, whereas miR-532/miR-3064 silencing promotes proliferation and invasion in OC cells.
No full text(A, B) Cell morphology of OC cells transfected with either miR-532/miR-3064 mimics (A) or miR-532/miR-3064 inhibitors (B); (C, D) Representative images of invaded ES-2 (C) and SKOV-3 (D) cells transfected as indicated; (E, F) Cell counting kit-8 assay (E) and transwell invasion assay (F) with OC cells transfected with miR-532/miR-3064 mimics or miR-532/miR-3064 inhibitors. **: P < 0.01.</p
miR-127 protects proximal tubule cells against ischemia/reperfusion : identification of Kinesin family member 3B as miR-127 target
No full textIschemia/reperfusion (I/R) is at the basis of renal transplantation and acute kidney injury. Molecular mechanisms underlying proximal tubule response to I/R will allow the identification of new therapeutic targets for both clinical settings. microRNAs have emerged as crucial and tight regulators of the cellular response to insults including hypoxia. Here, we have identified several miRNAs involved in the response of the proximal tubule cell to I/R. Microarrays and RT-PCR analysis of proximal tubule cells submitted to I/R mimicking conditions in vitro demonstrated that miR-127 is induced during ischemia and also during reperfusion. miR-127 is also modulated in a rat model of renal I/R. Interference approaches demonstrated that ischemic induction of miR-127 is mediated by Hypoxia Inducible Factor-1alpha (HIF-1α) stabilization. Moreover, miR-127 is involved in cell-matrix and cell-cell adhesion maintenance, since overexpression of miR-127 maintains focal adhesion complex assembly and the integrity of tight junctions. miR-127 also regulates intracellular trafficking since miR-127 interference promotes dextran-FITC uptake. In fact, we have identified the Kinesin Family Member 3B (KIF3B), involved in cell trafficking, as a target of miR-127 in rat proximal tubule cells. In summary, we have described a novel role of miR-127 in cell adhesion and its regulation by HIF-1α. We also identified for the first time KIF3B as a miR-127 target. Both, miR-127 and KIF3B appear as key mediators of proximal epithelial tubule cell response to I/R with potential al application in renal ischemic damage management
miR-132/212 knockout mice reveal roles for these miRNAs in regulating cortical synaptic transmission and plasticity
No full textmiR-132 and miR-212 are two closely related miRNAs encoded in the same intron of a small non-coding gene, which have been suggested to play roles in both immune and neuronal function. We describe here the generation and initial characterisation of a miR-132/212 double knockout mouse. These mice were viable and fertile with no overt adverse phenotype. Analysis of innate immune responses, including TLR-induced cytokine production and IFNβ induction in response to viral infection of primary fibroblasts did not reveal any phenotype in the knockouts. In contrast, the loss of miR-132 and miR-212, while not overtly affecting neuronal morphology, did affect synaptic function. In both hippocampal and neocortical slices miR-132/212 knockout reduced basal synaptic transmission, without affecting paired-pulse facilitation. Hippocampal long-term potentiation (LTP) induced by tetanic stimulation was not affected by miR-132/212 deletion, whilst theta burst LTP was enhanced. In contrast, neocortical theta burst-induced LTP was inhibited by loss of miR-132/212. Together these results indicate that miR-132 and/or miR-212 play a significant role in synaptic function, possibly by regulating the number of postsynaptic AMPA receptors under basal conditions and during activity-dependent synaptic plasticity
NEW INSIGHTS OF MIR-145 FUNCTION AND REGULATION IN HUMAN BREAST CANCER.
No full textmiR-145 is down-regulated in the majority of human cancers, including breast cancer (BC).
However, its role remains largely unknown. Here, I provide evidence for miR-145 induced
anti-proliferative and pro-apoptotic effect in several BC cell lines, which was not detected in
BC cells lacking a functional TP53 gene and exhibiting an estrogen receptor alfa (ESR1)
negative status. I found that miR-145 anti-proliferative effects were dependent upon TP53
activation and that activation of TP53 could in turn stimulates miR-145 expression. I also
found that miR-145 could repress the expression of ESR1 protein by direct interaction with
two sites within its gene coding sequence. My findings support the existence of a positive
regulatory loop where miR-145 directly targets ESR1 and indirectly activates TP53, which in
turn sustains miR-145 expression and reinforces miR-145 overall effects on proliferation and
apoptosis
The miR-590 C57T SNP reduces levels of miR-590-5p and miR-590-3p, without affecting the levels of pri-miR-590 and pre-miR-590.
No full text(A) Quantification of pri-miR-590 by qRT-PCR normalized by GAPDH. Mean ± SD (n = 3). HEK293T cells were transfected with the pri-miR-590-WT or pri-miR-590-SNP plasmids. The empty plasmid was used as negative control. (B-F) Northern blot images for pre-miRNA, miRNA, and U6 RNA using total RNA prepared from HEK293T cells transfected with the pri-miR-590-WT or pri-miR-590-SNP plasmids. The empty plasmid was used as negative control. Four biological replicates were analyzed for each transfection plasmid. Northern probes used are perfectly complementary to miR-590-5p (A), miR-590-3p-WT (B), miR-590-3p-SNP (C), miR-16-5p (D), and U6 RNA (E). The miR-590-3p-WT probe weakly cross-hybridized to miR-590-3p-SNP, and vice versa. (G) The abundance of pre-miR-590, miR-590-5p and miR-590-3p-(WT/SNP) relative to the mean value of miR-590-5p in the WT miR-590 gene plasmid transfection conditions. (H) The abundance of miR-16-5p normalized to the mean value of the pri-miR-590-WT plasmid transfection conditions. Mean ± SD (n = 4).</p
Role and regulation of miR-483 in cancer
No full textThe hsa-mir-483 locus is located at chromosome 11p15.5 within intron 2 of the IGF2 locus. Because of its location, de-regulated in Wilms’ tumor and other neoplasia, I hypothesized that this microRNA had a potential role in tumors. By analyzing 19 Wilms’ tumors, I proved that miR-483-3p is indeed over-expressed in 100% of the cases and a co-regulation with the over-expression of IGF2 was found.
However, several other types of common adult cancers exhibit high or even extremely high levels of miR-483-3p expression without IGF2 over-expression. Indeed, independently from IGF2, the expression of the miR-483-3p could also be induced by the oncoprotein β-catenin through a novel interaction with the basic Helix-Loop-Helix protein upstream stimulatory transcription factor 1 (USF1).
I also show that β-catenin itself is a target of miR-483-3p, triggering a negative regulative loop that becomes ineffective in cells harbouring activating mutations of β-catenin pathway.
The potential oncogenic role of miR-483-3p was supported by the findings that its ectopic expression protects cells from apoptosis and, conversely, its inhibition increase the level of apoptosis. To understand the mechanisms of its action, I investigated potential gene targets. Among these, an important pro-apoptotic protein, Puma, were inhibited by miR-483-3p. My results indicate that miR-483-3p functions as an anti-apoptotic oncogene, coordinately over-expressed with IGF2 in Wilms’ tumors or induced by β-catenin activation in other tumor types
Stress responsive miR-23a attenuates skeletal muscle atrophy by targeting MAFbx /atrogin-1
No full textMuscle atrophy occurs in many pathological states and results primarily from accelerated protein degradation by the ubiquitin-proteasome pathway. We used dexamethasone to induce muscle wasting and investigated the role of a microRNA (miRNA) in the control of muscle-specific E3 ubiquitin ligase MAFbx/atrogin-1. Here we show that miR-23a suppresses MAFbx/atrogin-1 translation by binding to 3'UTR of the mRNA. Furthermore, ectopic expression of miR-23a is sufficient to protect myocytes from atrophy in vitro and in vivo in response to dexamethasone treatment, and heat stress-induced miR-23a protects muscle from dexamethasone-induced muscle atrophy. Our surprising discovery of the physiological role of miR-23a in preventing the atrophy program should lay the basis not only for further understanding of the mechanisms of muscle wasting in diverse diseases, but also for developing novel therapies for these debilitating conditions
Functional microRNA high throughput screening reveals miR-9 as a central regulator of liver oncogenesis by affecting the PPARA-CDH1 pathway
No full textBackground: Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths, reflecting the aggressiveness of this type of cancer and the absence of effective therapeutic regimens. MicroRNAs have been involved in the pathogenesis of different types of cancers, including liver cancer. Our aim was to identify microRNAs that have both functional and clinical relevance in HCC and examine their downstream signaling effectors. Methods: MicroRNA and gene expression levels were measured by quantitative real-time PCR in HCC tumors and controls. A TargetScan algorithm was used to identify miR-9 downstream direct targets. Results: A high-throughput screen of the human microRNAome revealed 28 microRNAs as regulators of liver cancer cell invasiveness. MiR-9, miR-21 and miR-224 were the top inducers of HCC invasiveness and also their expression was increased in HCC relative to control liver tissues. Integration of the microRNA screen and expression data revealed miR-9 as the top microRNA, having both functional and clinical significance. MiR-9 levels correlated with HCC tumor stage and miR-9 overexpression induced SNU-449 and HepG2 cell growth, invasiveness and their ability to form colonies in soft agar. Bioinformatics and 3’UTR luciferase analyses identified E-cadherin (CDH1) and peroxisome proliferator-activated receptor alpha (PPARA) as direct downstream effectors of miR-9 activity. Inhibition of PPARA suppressed CDH1 mRNA levels, suggesting that miR-9 regulates CDH1 expression directly through binding in its 3’UTR and indirectly through PPARA. On the other hand, miR-9 inhibition of overexpression suppressed HCC tumorigenicity and invasiveness. PPARA and CDH1 mRNA levels were decreased in HCC relative to controls and were inversely correlated with miR-9 levels. Conclusions: Taken together, this study revealed the involvement of the miR-9/PPARA/CDH1 signaling pathway in HCC oncogenesis
HSV1 infection induces expression of the AOPEP-miR-23b/ miR-27b/ miR-24-1 locus.
No full text(A) (B) STING expression was analyzed by western blotting in human (A) HT1080 cells and (B) mouse NB41A3 cells upon HSV1 infection (MOI-5). (C) Figure depicting expression of miR-24 from 2 genetic loci. mir-24 is expressed in clusters from human chromosome 9 (miR-23b/ miR-27b/ miR-24-1) and chromosome 19 (miR-23a/ miR-27a/miR-24-2). Chromosome 9 cluster is expressed along with AOPEP mRNA. Human HT1080 cells were infected by HSV1 and cells were harvested at various time points. (D) miR-24, (E) miR-23b and (F) miR-27b expression levels were measured. (G) The expression of AOPEP mRNA was quantified. (H) Mouse NB41A3 cells were infected by HSV1 and cells were harvested at various time points to determine miR-24 levels. (D, E, F, G, H: Mean ± SEM, N = 3). *P<0.05, **P<0.01, ***P<0.001.</p
miR-124 in GSC niche cells affects daughter cell differentiation.
No full text(A and B) Ectopic expression of UAS-miR-124 in the TF and Cap cells of miR-124[6] (A) and miR-124[7] (B) mutant backgrounds using bab1-GAL4. Germaria were immunostained for Hts (red), Vasa (green), and DAPI (blue). In (A) and (B), the GSCs are highlighted by dashed circles. Scale bar: 10 μm. (C and D) Animals carrying UAS-miR-124 and GAL80ts; bab1-GAL4 (C) or UAS-miR-124 and C587-GAL4; GAL80ts (D) were raised at 18°C up to eclosion and then maintained at 18°C or 29°C for the number of days indicated before ovary dissection. The percentage of germaria carrying 5 or more spectrosome-containing cells is shown, and the number of analyzed germaria is above each bar. Significance of 18°C versus 29°C for the same time period was determined by Fisher’s exact two-sided test (* P P (E–G’) Germaria from wild-type females (E–E’), miR-124[6] (F–F’), and miR-124[7] (G–G’) mutants were immunostained for a marker (pMad) of BMP pathway activity. pMad (red) in germline cells (marked by Vasa antibody, green) was normally present only in GSCs (E–E’, highlighted by dashed circle) but was present in additional cells (indicated by white arrowheads) in the germaria of miR-124 mutants (F–F’, miR-124[6]; G–G’, miR-124[7]). (E), (F), and (G) show the merging of the 3 channels of pMad, Vasa, and DAPI (blue); (E’), (F’), and (G’) show pMad stained images in black and white. Scale bar: 10 μm. (H) Average numbers of cells with pMad staining per germarium in wild-type and 2 miR-124 mutants. Left to right: n = 103, 83, 113 biologically independent germaria. Data are presented as the mean ± SEM. Significance was analyzed by Kruskal–Wallis one-way ANOVA with Dunn’s test (*** P S1 Data. BMP, bone morphogenetic protein; GSC, germline stem cell; TF, terminal filament.</p
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