miR-483 is a self-regulating microRNA and can activate its own expression via USF1 in HeLa cells

Overexpression of Igf2-derived Mir483 inhibits Igf1 expression and leads to developmental growth restriction and metabolic dysfunction in mice

Mir483 is a conserved and highly expressed microRNA in placental mammals, embedded within the Igf2 gene. Its expression is dysregulated in a number of human diseases, including metabolic disorders and certain cancers. Here, we investigate the developmental regulation and function of Mir483 in vivo. We find that Mir483 expression is dependent on Igf2 transcription and the regulation of the Igf2/H19 imprinting control region. Transgenic Mir483 overexpression in utero causes fetal, but not placental, growth restriction through insulin-like growth factor 1 (IGF1) and IGF2 and also causes cardiovascular defects leading to fetal death. Overexpression of Mir483 post-natally results in growth stunting through IGF1 repression, increased hepatic lipid production, and excessive adiposity. IGF1 infusion rescues the post-natal growth restriction. Our findings provide insights into the function of Mir483 as a growth suppressor and metabolic regulator and suggest that it evolved within the INS-IGF2-H19 transcriptional region to limit excessive tissue growth through repression of IGF signaling.

Review of possible mechanisms of radiotherapy resistance in cervical cancer

Radiotherapy is one of the main treatments for cervical cancer. Early cervical cancer is usually considered postoperative radiotherapy alone. Radiotherapy combined with cisplatin is the standard treatment for locally advanced cervical cancer (LACC), but sometimes the disease will relapse within a short time after the end of treatment. Tumor recurrence is usually related to the inherent radiation resistance of the tumor, mainly involving cell proliferation, apoptosis, DNA repair, tumor microenvironment, tumor metabolism, and stem cells. In the past few decades, the mechanism of radiotherapy resistance of cervical cancer has been extensively studied, but due to its complex process, the specific mechanism of radiotherapy resistance of cervical cancer is still not fully understood. In this review, we discuss the current status of radiotherapy resistance in cervical cancer and the possible mechanisms of radiotherapy resistance, and provide favorable therapeutic targets for improving radiotherapy sensitivity. In conclusion, this article describes the importance of understanding the pathway and target of radioresistance for cervical cancer to promote the development of effective radiotherapy sensitizers.

The potential of cold-shock promoters for the expression of recombinant proteins in microbes and mammalian cells

BACKGROUND

Low-temperature expression of recombinant proteins may be advantageous to support their proper folding and preserve bioactivity. The generation of expression vectors regulated under cold conditions can improve the expression of some target proteins that are difficult to express in different expression systems. The cspA encodes the major cold-shock protein from Escherichia coli (CspA). The promoter of cspA has been widely used to develop cold shock-inducible expression platforms in E. coli. Moreover, it is often necessary to employ expression systems other than bacteria, particularly when recombinant proteins require complex post-translational modifications. Currently, there are no commercial platforms available for expressing target genes by cold shock in eukaryotic cells. Consequently, genetic elements that respond to cold shock offer the possibility of developing novel cold-inducible expression platforms, particularly suitable for yeasts, and mammalian cells.

CONCLUSIONS

This review covers the importance of the cellular response to low temperatures and the prospective use of cold-sensitive promoters to direct the expression of recombinant proteins. This concept may contribute to renewing interest in applying white technologies to produce recombinant proteins that are difficult to express.

BPA Decreases PDCD4 in Bovine Granulosa Cells Independently of miR-21 Inhibition

microRNAs (miRNAs) are susceptible to environmental factors that might affect cellular function and impose negative effects on female reproduction. miR-21 is the most abundant miRNA in bovine granulosa cells and is widely reported as affected by Bisphenol A (BPA) exposure, yet the cause and consequences are not entirely elucidated. BPA is a synthetic endocrine disruptor associated with poor fertility. miR-21 function in bovine granulosa cells is investigated utilizing locked nucleic acid (LNA) oligonucleotides to suppress miR-21. Before measuring apoptosis and quantifying miR-21 apoptotic targets PDCD4 and PTEN, transfection was optimized and validated. BPA was introduced to see how it affects miR-21 regulation and which BPA-mediated effects are influenced by miR-21. miR-21 knockdown and specificity against additional miRNAs were confirmed. miR-21 was found to have antiapoptotic effects, which could be explained by its effect on the proapoptotic target PDCD4, but not PTEN. Previous findings of miR-21 overexpression were validated using BPA treatments, and the temporal influence of BPA on miR-21 levels was addressed. Finally, BPA effects on upstream regulators, such as VMP1 and STAT3, explain the BPA-dependent upregulation of miR-21 expression. Overall, this research enhances our understanding of miR-21 function in granulosa cells and the mechanisms of BPA-induced reproductive impairment.

ZBED6 regulates Igf2 expression partially through its regulation of miR483 expression

The expression of Igf2 in mammals shows a complex regulation involving multiple promoters and epigenetic mechanisms. We previously identified a novel regulatory mechanism based on the interaction between the transcriptional factor ZBED6 and Igf2 intron. Disruption of the ZBED6-Igf2 interaction leads to a dramatic up-regulation of IGF2 expression postnatally. In the current study we characterize an additional layer of regulation involving miR483 encoded by another Igf2 intron. We found a highly significant up-regulation of miR483 expression when the ZBED6-Igf2 axis is disrupted in transgenic mice. Furthermore, CRISPR/Cas9 mediated knock-out of miR483 in C2C12 myoblast cells, both wild-type and cells with disrupted ZBED6-Igf2 axis (Igf2dGGCT), resulted in down-regulation of Igf2 expression and a reduced proliferation rate. This was further validated using miR483 mimics and inhibitors. RNA-seq analysis revealed a significant enrichment of genes involved in the PI3K-Akt signaling pathway among genes down-regulated in miR483-/- cells, including Igf2 down-regulation. The opposite pattern was observed in Igf2dGGCT cells, where Igf2 is up-regulated. Our data suggest a positive feedback between miR483 and Igf2 promoter activity, strongly affecting how ZBED6 controls Igf2 expression in various cell types.

The roles of microRNA in human cervical cancer

Although a potentially preventable disease, cervical cancer (CC) is the second most commonly diagnosed gynaecological cancer with at least 530,000 new cases annually, and the prognosis with CC is still poor. Studies suggest that aberrant expression of microRNA (miRNA) contributes to the progression of CC. As a group of small non-coding RNA with 18-25 nucleotides, miRNA regulate about one-third of all human genes. They function by repressing translation or inducing mRNA cleavage or degradation, including genes involved in diverse and important cellular processes, including cell cycling, proliferation, differentiation, and apoptosis. Results showed that misexpression of miRNA is closely related to the onset and progression of CC. This review will provide an overview of the function of miRNA in CC and the mechanisms involved in cervical carcinogenesis.

Systemic Delivery of Dysferlin Overlap Vectors Provides Long-Term Gene Expression and Functional Improvement for Dysferlinopathy

Dysferlinopathies comprise a family of disorders caused by mutations in the dysferlin (DYSF) gene, leading to a progressive dystrophy characterized by chronic muscle fiber loss, fat replacement, and fibrosis. To correct the underlying histopathology and function, expression of full-length DYSF is required. Dual adeno-associated virus vectors have been developed, defined by a region of homology, to serve as a substrate for reconstitution of the full 6.5 kb dysferlin cDNA. Previous work studied the efficacy of this treatment through intramuscular and regional delivery routes. To maximize clinical efficacy, dysferlin-deficient mice were treated systemically to target all muscles through the vasculature for efficacy and safety studies. Mice were evaluated at multiple time points between 4 and 13 months post treatment for dysferlin expression and functional improvement using magnetic resonance imaging and magnetic resonance spectroscopy and membrane repair. A systemic dose of 6 × 1012 vector genomes resulted in widespread gene expression in the muscles. Treated muscles showed a significant decrease in central nucleation, collagen deposition, and improvement of membrane repair to wild-type levels. Treated gluteus muscles were significantly improved compared to placebo-treated muscles and were equivalent to wild type in volume, intra- and extramyocellular lipid accumulation, and fat percentage using magnetic resonance imaging and magnetic resonance spectroscopy. Dual-vector treatment allows for production of full-length functional dysferlin with no toxicity. This confirms previous safety data and validates translation of systemic gene delivery for dysferlinopathy patients.

The Glucose-Regulated MiR-483-3p Influences Key Signaling Pathways in Cancer

The hsa-mir-483 gene, located within the IGF2 locus, transcribes for two mature microRNAs, miR-483-5p and miR-483-3p. This gene, whose regulation is mediated by the the CTNNB1/USF1 complex, shows an independent expression from its host gene IGF2. The miR-483-3p affects the Wnt/β-catenin, the TGF-β, and the TP53 signaling pathways by targeting several genes as CTNNB1, SMAD4, IGF1, and BBC3. Accordingly, miR-483-3p is associated with various tissues specific physiological properties as insulin and melanin production, as well as with cellular physiological functions such as wounding, differentiation, proliferation, and survival. Deregulation of miR-483-3p is observed in different types of cancer, and its overexpression can inhibit the pro-apoptotic pathway induced by the TP53 target effectors. As a result, the oncogenic characteristics of miR-483-3p are linked to the effect of some of the most relevant cancer-related genes, TP53 and CTNNB1, as well as to one of the most important cancer hallmark: the aberrant glucose metabolism of tumor cells. In this review, we summarize the recent findings regarding the miR-483-3p, to elucidate its functional role in physiological and pathological contexts, focusing overall on its involvement in cancer and in the TP53 pathway.

Comprehensive network of miRNA-induced intergenic interactions and a biological role of its core in cancer

MicroRNAs (miRNAs) are a family of short noncoding RNAs that posttranscriptionally regulate gene expression and play an important role in multiple cellular processes. A significant percentage of miRNAs are intragenic, which is often functionally related to their host genes playing either antagonistic or synergistic roles. In this study, we constructed and analyzed the entire network of intergenic interactions induced by intragenic miRNAs. We further focused on the core of this network, which was defined as a union of nontrivial strongly connected components, i.e., sets of nodes (genes) mutually connected via directed paths. Both the entire network and its core possessed statistically significant non-random properties. Specifically, genes forming the core had high expression levels and low expression variance. Furthermore, the network core did not split into separate components corresponding to individual signalling or metabolic pathways, but integrated genes involved in key cellular processes, including DNA replication, transcription, protein homeostasis and cell metabolism. We suggest that the network core, consisting of genes mutually regulated by their intragenic miRNAs, could coordinate adjacent pathways or homeostatic control circuits, serving as a horizontal inter-circuit link. Notably, expression patterns of these genes had an efficient prognostic potential for breast and colorectal cancer patients.

miR-483 targets SMAD4 to suppress chondrogenic differentiation of human mesenchymal stem cells

MicroRNAs (miRNAs) can regulate cellular differentiation processes by modulating multiple pathways simultaneously. Previous studies to analyze in vivo miRNA expression patterns in developing human limb cartilage tissue identified significant downregulation of miR-483 in hypertrophic chondrocytes relative to proliferating and differentiated chondrocytes. To test the function of miR-483 during chondrogenesis, lentiviral strategies were used to overexpress miR-483 during in vitro chondrogenesis of human bone marrow-derived mesenchymal stem cells (hBM-MSCs). While the in vivo expression patterns led us to hypothesize that miR-483 may enhance chondrogenesis or suppress hypertrophic marker expression, surprisingly, miR-483 overexpression reduced chondrocyte gene expression and cartilage matrix production. In addition, cell death was induced at later stages of the chondrogenesis assay. Mechanistic studies revealed that miR-483 overexpression resulted in downregulation of the TGF-β pathway member SMAD4, a known direct target of miR-483-3p. From these studies, we conclude that constitutive overexpression of miR-483 in hBM-MSCs inhibits chondrogenesis of these cells and does not represent an effective strategy to attempt to enhance chondrocyte differentiation and anabolism in this system in vitro. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2369-2377, 2017.

New insights in the clinical and translational relevance of miR483-5p in adrenocortical cancer

Adrenocortical cancer (ACC) is a rare aggressive malignancy. Recent ACC integrated genomics analysis contributed to redefine the risk groups on molecular basis, including tumor microRNAs (miRs), detectable also in the bloodstream. We developed a quantitative real-time (RT) assay for the measurement of miR483 and miR483-5p absolute levels in plasma samples. miR483/miR483-5p levels were evaluated in plasma samples of 27 patients with ACC before surgery and at follow-up.

Statistically significant differences in miR483-5p and miR483 levels were found between stage 1/2 and stage 3/4 ACCs in pre-surgery and post-surgery samples. ROC curve analysis of miR483–5p levels gave a prediction of the clinical stage (accuracy 0.917±0.084), with the best cut-off value of 0.221 ng/ml, prognosticating overall and recurrence-free survival. In a multivariate Cox analysis (HR 16.2, 95%CI[1.39-188.6, P<0.026]), miR483-5p was the only variable that significantly predicted recurrence, but not overall survival. In addition, miR483 and miR483-5p levels correlated with the number of circulating tumor cells (CTCs) detected in the same blood samples, independently of the timing of sampling. In conclusion, we demonstrated that miR483-5p absolute plasma levels in ACC patients are powerful molecular markers that may help in the follow-up of patients after surgery and chemotherapy, and contribute to more accurately classify and predict tumor progression.