Publications by authors named "Youngyoon Lee"

MicroRNAs (miRNAs) are small, yet profoundly influential, non-coding RNAs that base-pair with mRNAs to induce RNA silencing. Although the basic principles of miRNA biogenesis and function have been established, recent breakthroughs have yielded important new insights into the molecular mechanisms of miRNA biogenesis. In this Review, we discuss the metazoan miRNA biogenesis pathway step-by-step, focusing on the key biogenesis machinery, including the Drosha-DGCR8 complex (Microprocessor), exportin-5, Dicer and Argonaute.

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Background: Pitavastatin is a cholesterol-lowering drug and is widely used clinically. In addition to this effect, pitavastatin has shown the potential to induce apoptosis in cutaneous squamous cell carcinoma (SCC) cells.

Objective: The purpose of this study is to investigate the effects and possible action mechanisms of pitavastatin.

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Dicer has a key role in small RNA biogenesis, processing double-stranded RNAs (dsRNAs). Human DICER (hDICER, also known as DICER1) is specialized for cleaving small hairpin structures such as precursor microRNAs (pre-miRNAs) and has limited activity towards long dsRNAs-unlike its homologues in lower eukaryotes and plants, which cleave long dsRNAs. Although the mechanism by which long dsRNAs are cleaved has been well documented, our understanding of pre-miRNA processing is incomplete because structures of hDICER in a catalytic state are lacking.

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RNA silencing relies on specific and efficient processing of double-stranded RNA by Dicer, which yields microRNAs (miRNAs) and small interfering RNAs (siRNAs). However, our current knowledge of the specificity of Dicer is limited to the secondary structures of its substrates: a double-stranded RNA of approximately 22 base pairs with a 2-nucleotide 3' overhang and a terminal loop. Here we found evidence pointing to an additional sequence-dependent determinant beyond these structural properties.

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Article Synopsis
  • Time-restricted feeding (TRF) is being studied for its potential benefits in improving metabolic health related to obesity, particularly its impact on immune cells.
  • In an experiment, mice on a high-fat diet exhibited increased production of myeloid cells in the bone marrow and an increase in certain immune cells in circulation, both of which were reversed with TRF.
  • TRF did not affect bone marrow progenitor cell growth but lowered the expression of a key transcription factor for myeloid cell development, suggesting it might help stabilize immune cell levels during obesity.
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Background: Dermal fibroblasts play a pivotal role in hair follicle regeneration during wound repair. Recently, dermal fibroblast-conditioned medium (DFCM), which contains multi-peptide factors (MPFs), has been used to promote wound repair.

Aim: This study aimed to investigate the stimulatory effects of MPF-containing DFCM on hair growth.

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Studies suggest that time-restricted feeding (TRF) may prevent obesity and its commodities. At present, little is known about how TRF impacts immune cells, and whether such an effect is linked to altered metabolic parameters under condition of a high-fat diet (HFD)-induced obesity. To address these issues, we conducted a study in which we determined whether TRF has therapeutic efficacy against weight gain, adiposity, as well as associated immune cell disturbance found in obese mice.

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Maturation of canonical microRNA (miRNA) is initiated by DROSHA that cleaves the primary transcript (pri-miRNA). More than 1,800 miRNA loci are annotated in humans, but it remains largely unknown whether and at which sites pri-miRNAs are cleaved by DROSHA. Here, we performed in vitro processing on a full set of human pri-miRNAs (miRBase version 21) followed by sequencing.

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The NLRP3 inflammasome is a caspase-1 containing multi-protein complex that controls the release of IL-1β and plays important roles in the innate immune response. Since NLRP3 inflammasome is implicated in the pathogenesis of a variety of diseases, it has become an increasingly interested target in developing therapies for multiple diseases. We reported the current study to determine how luteolin, a natural phenolic compound found in many vegetables and medicinal herbs, would modulate NLRP3 inflammasome in both the in vivo and in vitro settings.

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TENT4 enzymes generate 'mixed tails' of diverse nucleotides at 3' ends of RNAs via nontemplated nucleotide addition to protect messenger RNAs from deadenylation. Here we discover extensive mixed tailing in transcripts of hepatitis B virus (HBV) and human cytomegalovirus (HCMV), generated via a similar mechanism exploiting the TENT4-ZCCHC14 complex. TAIL-seq on HBV and HCMV RNAs revealed that TENT4A and TENT4B are responsible for mixed tailing and protection of viral poly(A) tails.

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Article Synopsis
  • Strand selection during microRNA (miRNA) biogenesis can vary depending on the cellular environment, and understanding this process—particularly the phenomenon called "arm switching"—is crucial yet not fully understood.
  • The study identifies miR-324 as significantly affected by arm switching and highlights TUT4 and TUT7, terminal uridylyl transferases, as key regulators in the uridylation process which alters how the miRNA is processed.
  • In glioblastoma, higher levels of TUT4/7 and the 3' strand (3p) are observed, while the 5' strand (5p) is decreased; adjusting the ratio of these strands can hinder the proliferation of glioblastoma cells
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A power-constrained contrast-enhancement algorithm for emissive displays based on histogram equalization (HE) is proposed in this paper. We first propose a log-based histogram modification scheme to reduce overstretching artifacts of the conventional HE technique. Then, we develop a power-consumption model for emissive displays and formulate an objective function that consists of the histogram-equalizing term and the power term.

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The coding gain that can be achieved by improving the coding order of B frames in the H.264/AVC standard is investigated in this work. We first represent the coding order of B frames and their reference frames with a binary tree.

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