Publications by authors named "Sun-Ku Chung"

Article Synopsis
  • - The TP53 c.359A>G mutation creates a new splice site, disrupting normal p53 expression, but using an antisense morpholino oligomer (AMO) can fix this splicing issue, restoring normal levels of the p53 variant.
  • - The corrected p53 K120R protein is shown to have weakened ability to regulate the CDKN1A gene (which helps stop cell growth) but still promotes the BBC3 gene (which triggers cell death), indicating a partial retention of tumor suppressor functions.
  • - This research highlights the importance of acetylation at lysine 120 for p53's tumor-suppressing abilities and proposes that targeting mutant TP53 mRNA with AMO could be a
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Bacterial Artificial chromosome (BAC) recombineering is a powerful genetic manipulation tool for the efficient development of recombinant genetic resources. Long homology arms of more than 150 kb composed of BAC constructs not only substantially enhance genetic recombination events, but also provide a variety of single nucleotide polymorphisms (SNPs) that are useful markers for accurately docking BAC constructs at target sites. Even if the BAC construct is homologous to the sequences of the target region, different variations may be distributed between various SNPs within the region and those within the BAC construct.

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In cell-based regenerative medicine, induced pluripotent stem cells (iPSCs) generated from reprogrammed adult somatic cells have emerged as a useful cell source due to the lack of ethical concerns and the low risk of immune rejection. To address the risk of teratoma formation, which is a safety issue in iPSC-based cell therapy, it is essential to selectively remove undifferentiated iPSCs remaining in the iPSC-derived differentiated cell product prior to in vivo transplantation. In this study, we explored whether an ethanol extract of coptidis rhizoma (ECR) exhibited anti-teratoma activity and identified the active components involved in the selective elimination of undifferentiated iPSCs.

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Parkinson's disease (PD) is one of the most common neurodegenerative diseases caused by the loss of dopaminergic neurons in the substantia nigra pars compacta. Although the etiology of PD is still unclear, the death of dopaminergic neurons during PD progression was revealed to be associated with abnormal aggregation of α-synuclein, elevation of oxidative stress, dysfunction of mitochondrial functions, and increased neuroinflammation. In this study, the effects of Licochalcone D (LCD) on MG132-induced neurotoxicity in primitive neural stem cells (pNSCs) derived from reprogrammed iPSCs were investigated.

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Article Synopsis
  • * A range of gene correction tools, including ZFNs, CRISPR/Cas9, and BAC-based systems, are being utilized to address these mutations, especially in induced pluripotent stem cells (iPSCs).
  • * The text provides an overview of various gene editing methods and their applications in correcting the G2019S mutation, explaining both programmable and nonprogrammable systems.
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Background: Induced pluripotent stem cells (iPSCs) generated from reprogrammed adult somatic cells are considered as a promising cell source in cell-based regenerative medicine. To avoid teratoma formation, which is a safety issue in iPSC-based cell therapy, it is important to selectively remove undifferentiated iPSCs that remain in the differentiated cell product before in vivo transplantation. Caffeic acid (CAA, 3,4-dihydroxy-cinnamic acid) is a phenolic compound synthesized from various vegetables, fruits, and herbs; it has shown various pharmacological activities against inflammation, cancer, infection, diabetes, and neurodegenerative diseases.

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p53 is a transcription factor that is activated under DNA damage stress and regulates the expression of proapoptotic genes including the expression of growth arrest genes to subsequently determine the fate of cells. To investigate the functional differences of polymorphic p53 codon 72, we constructed isogenic lines encoding each polymorphic p53 codon 72 based on induced pluripotent stem cells, which can endogenously express each polymorphic p53 protein only, encoding either the arginine 72 (R72) variant or proline 72 (P72) variant, respectively. We found that there was no significant functional difference between P72 and R72 cells in growth arrest or apoptosis as a representative function of p53.

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Mutations in the Leucine-rich repeat kinase 2 () gene are the most prevalent cause of familial Parkinson's disease (PD). The increase in LRRK2 kinase activity observed in the pathogenic G2019S mutation is important for PD development. Several studies have reported that increased LRRK2 kinase activity and treatment with LRRK2 kinase inhibitors decreased and increased ciliogenesis, respectively, in mouse embryonic fibroblasts (MEFs) and retinal pigment epithelium (RPE) cells.

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Parkinson's disease (PD) is a common neurodegenerative disease, causing movement defects. The incidence of PD is constantly increasing and this disease is still incurable. Thus, understanding PD pathophysiology would be pivotal for the development of PD therapy, and various PD models have thus been already developed.

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Although brain organoids are an innovative technique for studying human brain development and disease by replicating the structural and functional properties of the developing human brain, some limitations such as heterogeneity and long-term differentiation (over 2 months) impede their application in disease modeling and drug discovery. In this study, we established simplified brain organoids (simBOs), composed of mature neurons and astroglial cells from expandable hPSC-derived primitive neural stem cells (pNSCs). simBOs can be rapidly generated in 2 weeks and have more homogeneous properties.

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Induced pluripotent stem cells (iPSCs) are regarded as a promising option for cell-based regenerative medicine. To obtain safe and efficient iPSC-based cell products, it is necessary to selectively eliminate the residual iPSCs prior to in vivo implantation due to the risk of teratoma formation. Bee venom (BV) has long been used in traditional Chinese medicine to treat inflammatory diseases and relieve pain, and has been shown to exhibit anti-cancer, anti-mutagenic, anti-nociceptive, and radioprotective activities.

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Induced pluripotent stem cells (iPSCs) have similar properties to embryonic stem cells in terms of indefinite self-renewal and differentiation capacity. After in vitro differentiation of iPSCs, undifferentiated iPSCs (USCs) may exist in cell therapy material and can form teratomas after in vivo transplantation. Selective elimination of residual USCs is, therefore, very important.

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Background: Induced pluripotent stem cells (iPSCs) are regarded as the best potential cell source for cell-based regenerative medicine. To develop a safe and efficient iPSC-based cell therapy, it is very important to avoid possible teratoma formation, which can arise from undifferentiated iPSCs (USCs) remaining among differentiated cell products. Dried bark of Magnolia officinalis (Magnolia cortex, MC) has long been used in traditional medicine to treat gastrointestinal ailments and allergic diseases, and has shown have various pharmacological activities, including anti-bacterial, anti-inflammatory, and anti-cancer effects.

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Continued CRISPR/Cas9-mediated editing activity that allows differential and asynchronous modification of alleles in successive cell generations expands allelic complexity. To understand the earliest events during CRISPR/Cas9 editing and the allelic selection among the progeny of subsequent cell divisions, we inspected in detail the genotypes of 4- and 8-cell embryos and embryonic stem cells (ESCs) after microinjection of a CRISPR toolkit into the zygotes. We found a higher editing frequency in 8-cell embryos than in 4-cell embryos, indicating that the CRISPR/Cas9 activity persisted through the 8-cell stage.

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Mutations in leucine-rich repeat kinase 2 (LRRK2) gene (LRRK2 G2019S) is a representative autosomal dominant mutation that can cause Parkinson's disease (PD). A bacterial artificial chromosome-based homologous recombination (BAC-based HR) system was utilized for gene therapy of LRRK2 G2019S-mutant induced pluripotent stem cells (iPSCs) produced by reprogramming episomal vectors. The gene-corrected iPSCs retained typical pluripotency required for their spontaneous differentiation into differentiated cells.

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Bisphenol A (BPA), a synthetic monomer commonly included in the daily products, has a structure similar to the estrogen receptor agonist. Therefore BPA has been anticipated to interfere with the hormone metabolisms and cause diverse pathological conditions. But the effects of BPA on the genetic landscapes of liver or hepatic cells have not been fully established.

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The point mutation that substitutes lysine with arginine at position 120 of human p53 has been characterized as a missense mutation. The K120R mutation renders the p53 protein disabled for acetylation and, as a result, defective for apoptotic function, which provides a mechanistic link between the missense mutation and tumorigenesis. However, we noticed the failures of tumorigenesis in mice with the mutation, and of the related studies to notice that it has arbitrarily reflected in amino acid change through a sequence modification (AGA) of the original tumor mutation (AGG) by codon degeneracy.

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Parkinson's disease (PD) is the second most common age-related neurodegenerative disorder. PD can result from a mutation of alpha-synuclein (α-SNCA), such as α-SNCA A53T. Using episomal vectors, induced pluripotent stem cells (iPSCs) were generated from skin fibroblasts with the α-SNCA A53T mutation.

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Everything in the surrounding universe can be attributed into five elements. Human organs can be also linked to the five elements. Cells, the smallest unit of the human body, consist of cellular organelles as little organs.

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Article Synopsis
  • - The study investigates the effects of Sagunja-Tang (SGT-4), a Korean herbal formula known for its antioxidant properties, on the efficiency of creating induced pluripotent stem cells (iPSCs) from human foreskin fibroblasts (HFFs) using specific transcription factors.
  • - SGT-4 is made up of four herbal ingredients, and its composition was analyzed through high-performance liquid chromatography (HPLC). Various techniques were used to evaluate the pluripotency of the iPSCs generated.
  • - Findings show that SGT-4 enhances the generation of iPSCs by promoting antioxidant activity and the activation of important enzymes, without significantly changing ATP levels, thus indicating its potential in stem cell
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The recent advent of induced pluripotent stem cells (iPSCs) and gene therapy tools has raised the possibility of autologous cell therapy for rare genetic diseases. However, cellular reprogramming is inefficient in certain diseases such as ataxia telangiectasia, Fanconi anemia, LIG4 syndrome, and fibrodysplasia ossificans progressiva syndrome, owing to interference of the disease-related genes. To overcome these therapeutic limitations, it is necessary to fundamentally correct the abnormal gene during or prior to the reprogramming process.

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Normalization of human RNA-seq experiments employing chimpanzee RNA as a spike-in standard is reported. Human and chimpanzee RNAs exhibit single nucleotide variations (SNVs) in average 210-bp intervals. Spike-in chimpanzee RNA would behave the same as the human counterparts during the whole NGS procedures owing to the high sequence similarity.

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Fibrodysplasia ossificans progressiva (FOP) syndrome is caused by mutation of the gene ACVR1, encoding a constitutive active bone morphogenetic protein type I receptor (also called ALK2) to induce heterotopic ossification in the patient. To genetically correct it, we attempted to generate the mutant ALK2-iPSCs (mALK2-iPSCs) from FOP-human dermal fibroblasts. However, the mALK2 leads to inhibitory pluripotency maintenance, or impaired clonogenic potential after single-cell dissociation as an inevitable step, which applies gene-correction tools to induced pluripotent stem cells (iPSCs).

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Despite the recent technological advances in DNA quantitation by sequencing, accurate delineation of the quantitative relationship among different DNA sequences is yet to be elaborated due to difficulties in correcting the sequence-specific quantitation biases. We here developed a novel DNA quantitation method via spiking-in a neighbor genome for competitive PCR amplicon sequencing (SiNG-PCRseq). This method utilizes genome-wide chemically equivalent but easily discriminable homologous sequences with a known copy arrangement in the neighbor genome.

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Article Synopsis
  • Abnormal lipid levels are linked to higher risks of atherosclerosis and cardiovascular disease, with variations in susceptibility based on Sasang constitutional types, particularly affecting the Tae-Eum (TE) type.
  • In a study of 8,597 participants, researchers found distinct associations between genetic variants and lipid levels, identifying 12 variants linked to lipid levels and 5 to dyslipidemia risk, particularly in the TE population.
  • The results suggest that specific genetic variants may increase the cardiovascular disease risk among TE type individuals by negatively impacting lipid levels, while similar variants in non-TE types showed neutral or compensatory effects.
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