• Biomedical Science Letters
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• v.29 no.4
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• pp.231-241
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• 2023

Messenger RNA (mRNA)-based vaccines and treatments have recently emerged as a promising strategy. Naked mRNA presents various limitations for direct delivery. Therefore, in this paper, Lipid Nanoparticles (LNPs) were utilized for the delivery of mRNA. Lipid nanoparticle (LNP) mRNA systems are highly effective as vaccines, but their efficacy for pulmonary delivery has not yet been fully established. Additionally, research on effective delivery systems and administration methods for vaccines is required to resolve the stability and degradation issues associated with naked mRNA delivery. This study aimed to determine mRNA delivery efficiency via the inhalation of a lipid nanoparticle (LNP) formulation designed specifically for pulmonary delivery. To this purpose, we built a library of seven LNP configurations with different lipid molar and N/P ratios and evaluated their encapsulation efficiency using gel retardation assay. Among the tested LNPs, LNP1, LNP2-2, and LNP3-2 demonstrated high transfection efficiency in vitro based on FACS analyses luciferase assays, and intracellular accumulation tests. The mRNA delivery efficiencies of the selected LNPs after inhalation and intravenous injection were compared and evaluated. LNP2-2 showed the highest mRNA expression in healthy mouse lungs when aerosolized and was found to be non-toxic. These results indicate that LNP2-2 is a promising carrier for lung mRNA delivery via inhalation.

• Korean Journal of Microbiology
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• v.26 no.1
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• pp.27-31
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• 1988

Biosynthesis and processing of cytoplasmic mRNA from heterogenous nuclear RNA (hn-RNA) in Aspergillus phoenicis were studied by $^{3}H$-uridine labeling and synchronous culture techniques during their life cycle. Incorporations of $^{3}H$-uridine into hn-RNA and mRNA were most rapid in vesicle-phialide fromation stage and diminished in hyphal growth stage. The processing of cytoplasmic mRNA from hn-RNA was proceeded more rapidly in hyphal growth and conidiophore formation stages than in conidia and vesicle-phialide formation stages. The specific radioactivities of hn-RNA and mRNA were very high in vesicle-phialide formation stage.

• Journal of Veterinary Clinics
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• v.40 no.2
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• pp.164-174
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• 2023

Canine splenic tumors (STs) are commonly diagnosed during imaging examinations, such as in X-ray and ultrasonography examinations, suggesting their higher prevalence, especially in older dogs. Despite this high prevalence, there are no effective treatment options for STs because of the difficulties in determining therapeutic targets. However, recently, the importance of microRNAs (miRNAs) has evolved owing to their ambivalent characteristics. Biomarkers and novel therapies using miRNAs have been well-studied in human cancer research compared to canine research, except for mammary gland tumors. Therefore, this study aimed to comparatively analyze miRNA expression profiles according to malignancy and biopsy sites to identify novel therapeutic and diagnostic targets. Tissue samples were collected directly from splenic tumor masses and immersed in RNAlater solution for further analysis. To investigate differentially expressed genes (DEGs) between tumor and normal tissues, we used RNA-seq and miRNA microarray analysis. Then, functional analysis based on DEGs was conducted to sort tumor-related DEGs. We found that cfa-miR-150 was upregulated in benign tumors, whereas cfa-miR-134 was upregulated in malignant tumors. Despite limited information on canine miRNAs, we identified two potential biomarkers for the differential diagnosis of STs.

• Molecules and Cells
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• v.42 no.5
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• pp.379-385
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• 2019

Non-coding RNAs (ncRNAs) comprise various RNA species, including small ncRNAs and long ncRNAs (lncRNAs). ncRNAs regulate various cellular processes, including transcription and translation of target messenger RNAs. Recent studies also indicate that ncRNAs affect organismal aging and conversely aging influences ncRNA levels. In this review, we discuss our current understanding of the roles of ncRNAs in aging and longevity, focusing on recent advances using the roundworm Caenorhabditis elegans. Expression of various ncRNAs, including microRNA (miRNA), tRNA-derived small RNA (tsRNA), ribosomal RNA (rRNA), PIWI-interacting RNA (piRNA), circular RNA (circRNA), and lncRNA, is altered during aging in C. elegans. Genetic modulation of specific ncRNAs affects longevity and aging rates by modulating established aging-regulating protein factors. Because many aging-regulating mechanisms in C. elegans are evolutionarily conserved, these studies will provide key information regarding how ncRNAs modulate aging and lifespan in complex organisms, including mammals.

• BMB Reports
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• v.50 no.11
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• pp.554-559
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• 2017

MicroRNAs (miRNAs) are ~22nt-long single-stranded RNA molecules that form a RNA-induced silencing complex with Argonaute (AGO) protein to post-transcriptionally downregulate their target messenger RNAs (mRNAs). To understand the regulatory mechanisms of miRNA, discovering the underlying functional rules for how miRNAs recognize and repress their target mRNAs is of utmost importance. To determine functional miRNA targeting rules, previous studies extensively utilized various methods including high-throughput biochemical assays and bioinformatics analyses. However, targeting rules reported in one study often fail to be reproduced in other studies and therefore the general rules for functional miRNA targeting remain elusive. In this review, we evaluate previously-reported miRNA targeting rules and discuss the biological impact of the functional miRNAs on gene-regulatory networks as well as the future direction of miRNA targeting research.

• Molecules and Cells
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• v.44 no.7
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• pp.538-539
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• 2021

• Molecules and Cells
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• v.39 no.12
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• pp.841-846
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• 2016

Local protein synthesis mediates precise spatio-temporal regulation of gene expression for neuronal functions such as long-term plasticity, axon guidance and regeneration. To reveal the underlying mechanisms of local translation, it is crucial to understand mRNA transport, localization and translation in live neurons. Among various techniques for mRNA analysis, fluorescence microscopy has been widely used as the most direct method to study localization of mRNA. Live-cell imaging of single RNA molecules is particularly advantageous to dissect the highly heterogeneous and dynamic nature of messenger ribonucleoprotein (mRNP) complexes in neurons. Here, we review recent advances in the study of mRNA localization and translation in live neurons using novel techniques for single-RNA imaging.

• Molecules and Cells
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• v.37 no.1
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• pp.1-8
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• 2014

Mammalian-cell messenger RNAs (mRNAs) are generated in the nucleus from precursor RNAs (pre-mRNAs, which often contain one or more introns) that are complexed with an array of incompletely inventoried proteins. During their biogenesis, pre-mRNAs and their derivative mRNAs are subject to extensive cis-modifications. These modifications promote the binding of distinct polypeptides that mediate a diverse array of functions needed for mRNA metabolism, including nuclear export, inspection by the nonsense-mediated mRNA decay (NMD) quality-control machinery, and synthesis of the encoded protein product. Ribonucleoprotein complex (RNP) remodeling through the loss and gain of protein constituents before and after pre-mRNA splicing, during mRNA export, and within the cytoplasm facilitates NMD, ensuring integrity of the transcriptome. Here we review the mRNP rearrangements that culminate in detection and elimination of faulty transcripts by mammalian-cell NMD.

• The Korean Journal of Zoology
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• v.33 no.2
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• pp.183-190
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• 1990

The present study exarnines the physiological alteradons in prolactin (PRL) messenger ribonucleic acid (mRNA) and serum PRL levels during the rat estrous cycle and the effed of naloxone, an endogenous oploid peptide receptor antagonist, on PRL gene expression during the rat estrous cycle. Adult female rats exhibiting at least two consecutive 4-day estrous cycles were used in this study. A single injection of naloxone (2mg/kg b.w.) or saline was given sc 30 mm prior to decapitation. Animals were sacrificed at 10:00 h of each stage of the estrous cycle, and at 2-h intervals from 10:00 h to 20:00 h during the proestrus. PRL mRNA and serum PRL levels were determined by a RNA-blot hybridization with the rat PRL cDNA probe and by a PRL radjoimmunoassay, respectively. PRL mRNA and serum PRL levels were not dramatically altered in the morning of each stage of diestrus I, II and proestrus, and naloxone failed to modify the two parameters. During estrus naloxone clearly suppressed serum PRL levels, but it was unable to modify PRL mRNA levels. A more detailed examination of the proestrus stage revealed that PRL mRNA and serum PRL levels were fluctuated as a function of time: PRL mRNA levels reached a maximum level at 12:00 h and gradually decreased until 18:00 h. PRL mRNA levels then rose at 20:00 h. No difference of PRL mRNA levels between the control and naloxone-treated groups was observed. Changes in serum PRL levek during proestrus were conversely related to changes in PRL mRNA: serum PRL levels were low from 10:00 h to 14:00 h, then increased and reached a maximum level at 16:00-18:00 h. Following then, serum PRL levels were decreased. Naloxone was effective in suppressing the charaderistic afternoon surge of PRL from 16:00 h to 20:00 h. These data clearly showed that alterations in PRL mRNA levels were conversely correlated with changes mn serum PRL levels on proestrus, indicating a differential regulation of PRL gene expression and secretion.

• BMB Reports
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• v.55 no.3
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• pp.125-135
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• 2022

Continuously renewing the proteome, translation is exquisitely controlled by a number of dedicated factors that interact with the ribosome. The RNA helicase DDX3 belonging to the DEAD box family has emerged as one of the critical regulators of translation, the failure of which is frequently observed in a wide range of proliferative, degenerative, and infectious diseases in humans. DDX3 unwinds double-stranded RNA molecules with coupled ATP hydrolysis and thereby remodels complex RNA structures present in various protein-coding and noncoding RNAs. By interacting with specific features on messenger RNAs (mRNAs) and 18S ribosomal RNA (rRNA), DDX3 facilitates translation, while repressing it under certain conditions. We review recent findings underlying these properties of DDX3 in diverse modes of translation, such as cap-dependent and cap-independent translation initiation, usage of upstream open reading frames, and stress-induced ribonucleoprotein granule formation. We further discuss how disease-associated DDX3 variants alter the translation landscape in the cell.