Abstract 1: Role of MicroRNAs in Postranscriptional Regulation of Apolipoprotein B-100 mRNA

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Sahar A Basir ◽  
Tiffany Asante ◽  
Khosrow Adeli
Keyword(s):  
Protein Synthesis ◽  
Mrna Expression ◽  
Apolipoprotein B ◽  
Opposite Effect ◽  
Translational Repression ◽  
Luciferase Reporter ◽  
Hepatoma Cell Line ◽  
P Bodies ◽  
Apob Mrna ◽  
Reporter Assays

Hepatic apolipoprotein B-100 (apoB) synthesis and secretion appears to be regulated largely at the posttranscriptional and posttranslational levels. MicroRNAs (miRNAs) are among posttranscriptional regulators of gene expression that bind to complementary sequences on target messenger RNA (mRNA) transcripts, usually resulting in translational repression or degradation. It is unknown whether specific miRNAs are involved in posttranscriptional regulation of apoB mRNA. We performed bioinformatic analysis, showing that two specific miRNAs with satisfactory E-values level (with levels indicating greater similarity between the input and its match) namely, miR-544 (E-value = 0.91) and miR-1202 (E-value=0.86) have potential to interact with 3’ and 5’ UTR of apoB, respectively. We hypothesized that the interaction of these specific miRNAs (miR-544 and miR-1202) with the 3’ and 5’UTR of apoB mRNA leads to apoB mRNA translational repression and/or activation. Using a human hepatoma cell line model, HepG2, the effects of overexpressed miRNAs and inhibition of endogenous miRNAs on the expression of apoB mRNA and apoB protein synthesis were investigated. We further examined the effect of these miRNAs on apoB mRNA traffic into cytoplasmic P-bodies. Transfection of HepG2 cells with miR-544 led to a significant reduction in apoB mRNA expression and protein synthesis and induced an increase in the co-localization of apoB mRNA into P-bodies. The opposite effect was observed when anti-miR-544 was employed to inhibit the endogenous miR-544. Results from luciferase reporter assays indicated that the effects of miR-544 may be mediated via interaction with the 3’UTR of apoB mRNA. In contrast to miR-544, miR-1202 overexpression induced an increase in apoB mRNA expression and protein synthesis. Similarly, the opposite effect was observed when using anti-miR-1202. Data from luciferase reporter assays showed an increased expression of the reporter gene in constructs carrying 5’UTR of apoB mRNA suggesting that miR-1202 may function via the 5’UTR. In summary, these data demonstrate that specific miRNAs are involved in the regulation of expression and translational control of apoB mRNA in hepatocytes. However, these miRNAs do not appear to mediate insulin regulation.

scholarly journals Circ_0026344 overexpression inhibits the migration, invasion, and enhances apoptosis of colorectal cancer cells by sponging miR-31

2020 ◽  
Author(s):  
Ye Jin ◽  
Lingli Yu ◽  
Bin Zhang ◽  
Yun Chen ◽  
Changfeng Liu ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Flow Cytometry ◽  
Wound Healing ◽  
Cell Lines ◽  
Opposite Effect ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Colorectal Cancer Cells ◽  
Reporter Assays ◽  
E Cadherin

Abstract Background: Circ_0026344 was reported to be associated with the metastasis of colorectal cancer (CRC). This study aimed to investigate the expression of circ_0026344 in CRC and the effect mechanisms of circ_0026344 on CRC.Methods: The expressions of circ_0026344 and miR-31 in clinical CRC tissues or CRC cell lines were analyzed by qPCR. The target of circ_0026344 was predicted and verified by CircInteractome and dual-luciferase reporter assays. The correlation between circ_0026344 and miR-31 expression was analyzed using Pearson analysis. After the CRC cells were overexpressed circ_0026344 or miR-31 or silenced circ_0026344, the viability, apoptosis, migration, and invasion of CRC cells were evaluated by CCK-8, flow cytometry, wound healing, and transwell. Also, the expressions of miR-31, Bcl-2, Bax, E-cadherin, and N-cadherin in the cells were detected by qPCR or Western blot. Results: Circ_0026344 was low-expressed in CRC tissues and cell lines. Circ_0026344 sponged miR-31 which was high-expressed in CRC tissues. The expression of circ_0026344 was negatively correlated to the expression of miR-31. The miR-31 expression could be down-regulated by circ_0026344 overexpression. Circ_0026344 overexpression inhibited the cell viability, migration, and invasion; and enhanced the apoptosis of CRC cells. Circ_0026344 overexpression decreased the expressions of Bcl-2 and N-cadherin and increased the expressions of Bax and E-cadherin in CRC cells. Circ_0026344 silencing and miR-31 overexpression had an opposite effect on CRC cells as circ_0026344 overexpression. Furthermore, miR-31 overexpression counteracted the effect of circ_0026344 overexpression.Conclusion: Circ_0026344 overexpression inhibited the migration, invasion, and enhanced apoptosis of CRC cells by sponging miR-31.

scholarly journals Role of MiR-98 and Its Underlying Mechanisms in Systemic Lupus Erythematosus

2018 ◽  
Vol 45 (10) ◽  
pp. 1397-1405 ◽  
Author(s):  
Lin Xie ◽  
Jinhua Xu
Keyword(s):  
T Cells ◽  
Lupus Erythematosus ◽  
Cd4 T Cells ◽  
Opposite Effect ◽  
Luciferase Reporter ◽  
Qrt Pcr ◽  
Fas Mrna ◽  
Reporter Assays ◽  
Underlying Mechanisms

Objective.T-lymphocyte apoptosis plays a critical role in the pathogenesis of systemic lupus erythematosus (SLE). However, the underlying regulatory mechanisms of apoptosis in SLE remain unclear. The aim of this study was to explore the role of miR-98 in SLE and its underlying mechanisms.Methods.Western blotting and quantitative reverse transcription PCR (qRT-PCR) were used to analyze miR-98 and Fas expression. Luciferase reporter assays were performed to identify miR-98 targets. To modify miRNA levels, miR-98 mimics and inhibitor were transfected into cells. A lentiviral construct was used to overexpress the level of Fas in SLE CD4+ T cells. Gene and protein expression were determined by qRT-PCR and Western blotting. Apoptosis levels were evaluated by annexin V staining and flow cytometry.Results.Compared to those of healthy donors, miR-98 was downregulated in SLE CD4+ T cells, whereas Fas mRNA and protein expression were upregulated. Upregulation of miR-98 by mimic transfection protected Jurkat cells against Fas-mediated apoptosis at both mRNA and protein levels, while miR-98 inhibitor induced the completely opposite effect. Luciferase reporter assays demonstrated that miR-98 directly targeted Fas mRNA. Further, miR-98 inhibitor induced apoptosis in primary healthy CD4+ T cells through the Fas-caspase axis, while upregulation of miR-98 in SLE CD4+ T cells led to the opposite effect.Conclusion.The current study revealed that downregulation of miR-98 induces apoptosis by modulating the Fas-mediated apoptotic signaling pathway in SLE CD4+ T cells. These results suggest that miR-98 might serve as a potential target for SLE treatment.

scholarly journals m(6)A mRNA Methylation Regulates Ferroptosis in HPSCC by Targeting NFE2L2/NRF2

2021 ◽  
Author(s):  
Jing Ye ◽  
Xiaozhen Chen ◽  
Bing Liao ◽  
Xiaohua Jiang ◽  
Zhihuai Dong ◽  
...  
Keyword(s):  
Opposite Effect ◽  
Bioinformatics Analysis ◽  
Luciferase Reporter ◽  
Dot Blot ◽  
Transcriptional Inhibition ◽  
Reporter Assays ◽  
Nrf2 Expression ◽  
Insight Into ◽  
Dependent Mechanism

Abstract Background Emerging as the most abundant posttranscriptional internal mRNA modification in eukaryotes, N6-methyladenosine (m6A) modification has gathered tremendous scientific interest in recent years. However, no study addresses the role of m6A modification in ferroptosis. Here, we showed that m6A modifications are decreased in RSL3-induced ferroptosis in hypopharyngeal squamous cell carcinoma (HPSCC). We found that AlkB homolog 5 (ALKBH5), one of the m6A demethylases, is the primary factor involved in aberrant m6A modification. Methods Bioinformatics analysis, sample analysis, cell biological analyses and transcriptome sequencing were performed to evaluate the correlation between m6A modification and ferroptosis as well as molecular mechanism of ALKBH5 function. Transcriptome-wide m6A-seq and RIP-seq data and following m6A dot blot, MeRIP-qPCR, RIP-qPCR and dual luciferase reporter assays were mapped to screen and validate the candidate targets of ALKBH5. Results ALKBH5-knockdown impaired ferroptotic cell death in HPSCC. However, overexpression of ALKBH5 has an opposite effect, suggesting that ALKBH5 is a positive regulator of ferroptosis. Mechanistically, ALKBH5-mediated m6A demethylation led to a post-transcriptional inhibition of NFE2L2/NRF2, the central player in the regulation of antioxidant molecules in cells, at two m6A residues in the 3ʹ-UTR. Therefore, knocking down ALKBH5 subsequently increases the expression levels of NFE2L2/NRF2 and increased cell resistance to ferroptosis. In addition, m6A-mediated NFE2L2/NRF2 stabilization relied on the m6A reader IGF2BP2. Conclusion ALKBH5 functions as a tumor suppresser through ferroptosis in HPSCC. ALKBH5 destabilizes NFE2L2/NRF2 expression in HPSCC through an m6A-IGF2BP2-dependent mechanism. Together, our work uncovers a critical link between ALKBH5-NFE2L2/NRF2 and ferroptosis, providing insight into the functional importance of the reversible mRNA m6A methylation and its modulators in HPSCC.

Focusing on mRNA Granules and Stalled Polysomes Amidst Diverse Mechanisms Underlying mRNA Transport, mRNA Storage, and Local Translation

2020 ◽  
Author(s):  
Mina N. Anadolu ◽  
Wayne S. Sossin
Keyword(s):  
Protein Synthesis ◽  
Liquid Phase ◽  
Mrna Translation ◽  
Rna Transport ◽  
P Bodies ◽  
Rna Granules ◽  
Mrna Granules ◽  
Transport Particle ◽  
As Stress ◽  
The Individual

In neurons, mRNAs are transported to distal sites to allow for localized protein synthesis. There are many diverse mechanisms underlying this transport. For example, an individual mRNA can be transported in an RNA transport particle that is tailored to the individual mRNA and its associated binding proteins. In contrast, some mRNAs are transported in liquid-liquid phase separated structures called neuronal RNA granules that are made up of multiple stalled polysomes, allowing for rapid initiation-independent production of proteins required for synaptic plasticity. Moreover, neurons have additional types of liquid-liquid phase–separated structures containing mRNA, such as stress granules and P bodies. This chapter discusses the relationships between all of these structures, what proteins distinguish them, and the possible roles they play in the complex control of mRNA translation at distal sites that allow neurons to use protein synthesis to refine their local proteome in many different ways.

scholarly journals TEAD4 modulated LncRNA MNX1-AS1 contributes to gastric cancer progression partly through suppressing BTG2 and activating BCL2

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
You Shuai ◽  
Zhonghua Ma ◽  
Weitao Liu ◽  
Tao Yu ◽  
Changsheng Yan ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cancer Progression ◽  
Molecular Mechanisms ◽  
Mechanistic Model ◽  
Ectopic Expression ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Tissue Samples ◽  
Reporter Assays

Abstract Background Gastric cancer (GC) is the third leading cause of cancer-related mortality globally. Long noncoding RNAs (lncRNAs) are dysregulated in obvious malignancies including GC and exploring the regulatory mechanisms underlying their expression is an attractive research area. However, these molecular mechanisms require further clarification, especially upstream mechanisms. Methods LncRNA MNX1-AS1 expression in GC tissue samples was investigated via microarray analysis and further determined in a cohort of GC tissues via quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays. Cell proliferation and flow cytometry assays were performed to confirm the roles of MNX1-AS1 in GC proliferation, cell cycle regulation, and apoptosis. The influence of MNX1-AS1 on GC cell migration and invasion was explored with Transwell assays. A xenograft tumour model was established to verify the effects of MNX1-AS1 on in vivo tumourigenesis. The TEAD4-involved upstream regulatory mechanism of MNX1-AS1 was explored through ChIP and luciferase reporter assays. The mechanistic model of MNX1-AS1 in regulating gene expression was further detected by subcellular fractionation, FISH, RIP, ChIP and luciferase reporter assays. Results It was found that MNX1-AS1 displayed obvious upregulation in GC tissue samples and cell lines, and ectopic expression of MNX1-AS1 predicted poor clinical outcomes for patients with GC. Overexpressed MNX1-AS1 expression promoted proliferation, migration and invasion of GC cells markedly, whereas decreased MNX1-AS1 expression elicited the opposite effects. Consistent with the in vitro results, MNX1-AS1 depletion effectively inhibited the growth of xenograft tumour in vivo. Mechanistically, TEAD4 directly bound the promoter region of MNX1-AS1 and stimulated the transcription of MNX1-AS1. Furthermore, MNX1-AS1 can sponge miR-6785-5p to upregulate the expression of BCL2 in GC cells. Meanwhile, MNX1-AS1 suppressed the transcription of BTG2 by recruiting polycomb repressive complex 2 to BTG2 promoter regions. Conclusions Our findings demonstrate that MNX1-AS1 may be able to serve as a prognostic indicator in GC patients and that TEAD4-activatd MNX1-AS1 can promote GC progression through EZH2/BTG2 and miR-6785-5p/BCL2 axes, implicating it as a novel and potent target for the treatment of GC.

scholarly journals Circular RNA mmu_circ_0005019 inhibits fibrosis of cardiac fibroblasts and reverses electrical remodeling of cardiomyocytes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Na Wu ◽  
Chengying Li ◽  
Bin Xu ◽  
Ying Xiang ◽  
Xiaoyue Jia ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Cardiac Fibroblasts ◽  
Circular Rna ◽  
Protective Role ◽  
Luciferase Reporter ◽  
Loss Of Function ◽  
Candidate Target ◽  
Paired Control ◽  
Reporter Assays ◽  
And Migration

Abstract Background Circular RNA (circRNA) have been reported to play important roles in cardiovascular diseases including myocardial infarction and heart failure. However, the role of circRNA in atrial fibrillation (AF) has rarely been investigated. We recently found a circRNA hsa_circ_0099734 was significantly differentially expressed in the AF patients atrial tissues compared to paired control. We aim to investigate the functional role and molecular mechanisms of mmu_circ_0005019 which is the homologous circRNA in mice of hsa_circ_0099734 in AF. Methods In order to investigate the effect of mmu_circ_0005019 on the proliferation, migration, differentiation into myofibroblasts and expression of collagen of cardiac fibroblasts, and the effect of mmu_circ_0005019 on the apoptosis and expression of Ito, INA and SK3 of cardiomyocytes, gain- and loss-of-function of cell models were established in mice cardiac fibroblasts and HL-1 atrial myocytes. Dual-luciferase reporter assays and RIP were performed to verify the binding effects between mmu_circ_0005019 and its target microRNA (miRNA). Results In cardiac fibroblasts, mmu_circ_0005019 showed inhibitory effects on cell proliferation and migration. In cardiomyocytes, overexpression of mmu_circ_0005019 promoted Kcnd1, Scn5a and Kcnn3 expression. Knockdown of mmu_circ_0005019 inhibited the expression of Kcnd1, Kcnd3, Scn5a and Kcnn3. Mechanistically, mmu_circ_0005019 exerted biological functions by acting as a miR-499-5p sponge to regulate the expression of its target gene Kcnn3. Conclusions Our findings highlight mmu_circ_0005019 played a protective role in AF development and might serve as an attractive candidate target for AF treatment.

LncRNA LINC00858 enhances cervical cancer cell growth through miR-3064-5p/ VMA21 axis

2021 ◽  
pp. 1-11
Author(s):  
Min Wei ◽  
Youguo Chen ◽  
Wensheng Du
Keyword(s):  
Cervical Cancer ◽  
Cell Proliferation ◽  
Cell Apoptosis ◽  
Luciferase Reporter ◽  
Cancer Cell Growth ◽  
Protein Coding ◽  
Gynecological Malignancy ◽  
Promising Therapeutic Target ◽  
Proliferation And Apoptosis ◽  
Reporter Assays

BACKGROUND: Cervical cancer (CC) is the most common form of gynecological malignancy. Long intergenic non-protein coding RNA 858 (LINC00858) has been identified to participate in multiple cancers. However, the role and mechanism of LINC00858 in CC cells are still elusive. AIM: The aim of this study is to explore the biological functions and mechanisms of LINC00858 in CC cells. METHODS: RT-qPCR analysis was used to examine the expression of LINC00858 in CC cells. EdU and colony formation assay were utilized to assess cell proliferation. TUNEL assay and flow cytometry assay were conducted to assess cell apoptosis. The mechanism regarding LINC00858 was certified through RNA pull down, RIP and luciferase reporter assays. RESULTS: The up-regulated LINC00858 was detected in CC cells. Reduction of LINC00858 effectively subdued CC cells proliferation and stimulated cell apoptosis. LINC00858 was determined to bind with miR-3064-5p and up-regulate VMA21 in CC cells. In rescue assays, miR-3064-5p down-regulation and VMA21 up-regulation were able to counteract the effect caused by LINC00858 decrease on CC cell proliferation and apoptosis. CONCLUSION: LINC00858 enhances cell proliferation, while restraining cell apoptosis in CC through targeting miR-3064-5p/VMA21 axis, implying that LINC00858 may serve as a promising therapeutic target for CC.

scholarly journals MITF induces escape from innate immunity in melanoma

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Luis Sánchez-del-Campo ◽  
Román Martí-Díaz ◽  
María F. Montenegro ◽  
Rebeca González-Guerrero ◽  
Trinidad Hernández-Caselles ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Nk Cells ◽  
Nk Cell ◽  
Luciferase Reporter ◽  
Damage Repair ◽  
Reporter Assays ◽  
Underlying Mechanisms ◽  
Nk Cytotoxicity

Abstract Background The application of immune-based therapies has revolutionized cancer treatment. Yet how the immune system responds to phenotypically heterogeneous populations within tumors is poorly understood. In melanoma, one of the major determinants of phenotypic identity is the lineage survival oncogene MITF that integrates diverse microenvironmental cues to coordinate melanoma survival, senescence bypass, differentiation, proliferation, invasion, metabolism and DNA damage repair. Whether MITF also controls the immune response is unknown. Methods By using several mouse melanoma models, we examine the potential role of MITF to modulate the anti-melanoma immune response. ChIP-seq data analysis, ChIP-qPCR, CRISPR-Cas9 genome editing, and luciferase reporter assays were utilized to identify ADAM10 as a direct MITF target gene. Western blotting, confocal microscopy, flow cytometry, and natural killer (NK) cytotoxicity assays were used to determine the underlying mechanisms by which MITF-driven phenotypic plasticity modulates melanoma NK cell-mediated killing. Results Here we show that MITF regulates expression of ADAM10, a key sheddase that cleaves the MICA/B family of ligands for NK cells. By controlling melanoma recognition by NK-cells MITF thereby controls the melanoma response to the innate immune system. Consequently, while melanoma MITFLow cells can be effectively suppressed by NK-mediated killing, MITF-expressing cells escape NK cell surveillance. Conclusion Our results reveal how modulation of MITF activity can impact the anti-melanoma immune response with implications for the application of anti-melanoma immunotherapies.

scholarly journals Tumor Suppressive Role of miR-342-5p in Human Chondrosarcoma Cells and 3D Organoids

2021 ◽  
Vol 22 (11) ◽  
pp. 5590
Author(s):  
Clément Veys ◽  
Abderrahim Benmoussa ◽  
Romain Contentin ◽  
Amandine Duchemin ◽  
Emilie Brotin ◽  
...  
Keyword(s):  
Luciferase Reporter ◽  
Functional Screening ◽  
Western Blots ◽  
Egfr Expression ◽  
Reporter Assays ◽  
Direct Target ◽  
Induced Apoptosis ◽  
First Time

Chondrosarcomas are malignant bone tumors. Their abundant cartilage-like extracellular matrix and their hypoxic microenvironment contribute to their resistance to chemotherapy and radiotherapy, and no effective therapy is currently available. MicroRNAs (miRNAs) may be an interesting alternative in the development of therapeutic options. Here, for the first time in chondrosarcoma cells, we carried out high-throughput functional screening using impedancemetry, and identified five miRNAs with potential antiproliferative or chemosensitive effects on SW1353 chondrosarcoma cells. The cytotoxic effects of miR-342-5p and miR-491-5p were confirmed on three chondrosarcoma cell lines, using functional validation under normoxia and hypoxia. Both miRNAs induced apoptosis and miR-342-5p also induced autophagy. Western blots and luciferase reporter assays identified for the first time Bcl-2 as a direct target of miR-342-5p, and also Bcl-xL as a direct target of both miR-342-5p and miR-491-5p in chondrosarcoma cells. MiR-491-5p also inhibited EGFR expression. Finally, only miR-342-5p induced cell death on a relevant 3D chondrosarcoma organoid model under hypoxia that mimics the in vivo microenvironment. Altogether, our results revealed the tumor suppressive activity of miR-342-5p, and to a lesser extent of miR-491-5p, on chondrosarcoma lines. Through this study, we also confirmed the potential of Bcl-2 family members as therapeutic targets in chondrosarcomas.

scholarly journals Molecular Cloning and Functional Characterization of Three 5-HT Receptor Genes (HTR1B, HTR1E and HTR1F) in Chickens

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 891
Author(s):  
Caiyun Sun ◽  
Yang Qiu ◽  
Qin Ren ◽  
Xiao Zhang ◽  
Baolong Cao ◽  
...  
Keyword(s):  
Serotonin Receptor ◽  
Functional Characterization ◽  
Brain Regions ◽  
Luciferase Reporter ◽  
Molecular Characteristics ◽  
Intracellular Camp ◽  
Pituitary Cells ◽  
Dependent Manner ◽  
Serotonin Signaling ◽  
Reporter Assays

The serotonin (5-hydroxytryptamine, 5-HT) signaling system is involved in a variety of physiological functions, including the control of cognition, reward, learning, memory, and vasoconstriction in vertebrates. Contrary to the extensive studies in the mammalian system, little is known about the molecular characteristics of the avian serotonin signaling network. In this study, we cloned and characterized the full-length cDNA of three serotonin receptor genes (HTR1B, HTR1E and HTR1F) in chicken pituitaries. Synteny analyses indicated that HTR1B, HTR1E and HTR1F were highly conserved across vertebrates. Cell-based luciferase reporter assays showed that the three chicken HTRs were functional, capable of binding their natural ligands (5-HT) or selective agonists (CP94253, BRL54443, and LY344864) and inhibiting intracellular cAMP production in a dose-dependent manner. Moreover, activation of these receptors could stimulate the MAPK/ERK signaling cascade. Quantitative real-time PCR analyses revealed that HTR1B, HTR1E and HTR1F were primarily expressed in various brain regions and the pituitary. In cultured chicken pituitary cells, we found that LY344864 could significantly inhibit the secretion of PRL stimulated by vasoactive intestinal peptide (VIP) or forskolin, revealing that HTR1F might be involved in the release of prolactin in chicken. Our findings provide insights into the molecular mechanism and facilitate a better understanding of the serotonergic modulation via HTR1B, HTR1E and HTR1F in avian species.

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