• BMB Reports
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• v.55 no.3
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• pp.142-147
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• 2022

Human pluripotent stem cells (PSCs) have been utilized as a promising source in regenerative medicine. However, the risk of teratoma formation that comes with residual undifferentiated PSCs in differentiated cell populations is most concerning in the clinical use of PSC derivatives. Here, we report that a monoclonal antibody (mAb) targeting PSCs could distinguish undifferentiated PSCs, with potential teratoma-forming activity, from differentiated PSC progeny. A panel of hybridomas generated from mouse immunization with H9 human embryonic stem cells (hESCs) was screened for ESC-specific binding using flow cytometry. A novel mAb, K312, was selected considering its high stem cell-binding activity, and this mAb could bind to several human induced pluripotent stem cells and PSC lines. Cell-binding activity of K312 was markedly decreased as hESCs were differentiated into embryoid bodies or by retinoic acid treatment. In addition, a cell population negatively isolated from undifferentiated or differentiated H9 hESCs via K312 targeting showed a significantly reduced expression of pluripotency markers, including Oct4 and Nanog. Furthermore, K312-based depletion of pluripotent cells from differentiated PSC progeny completely prevented teratoma formation. Therefore, our findings suggest that K312 is utilizable in improving stem cell transplantation safety by specifically distinguishing residual undifferentiated PSCs.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.61-62
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• 2000

No Abstract, See Full Text

• Proceedings of the Microbiological Society of Korea Conference
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• 2000.10a
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• pp.49-56
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• 2000

• Proceedings of the Korean Society of Toxicology Conference
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• 2005.11a
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• pp.154-163
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• 2005

• Mass Spectrometry Letters
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• v.6 no.3
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• pp.53-58
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• 2015

Recombinant erythropoietins (EPOs) are an important class of biotherapeutics that stimulate red blood cell production. The quality, safety, and potency of EPO variants are determined largely by their glycosylation, which makes up nearly half their mass. Thus, detailed glycomic analyses are important to assess biotherapeutic quality and establish the equivalency of biosimilar EPOs now coming to market. High-resolution mass spectrometry (MS) has recently emerged as the premier tool for glycan analysis in EPOs. Using the accurate mass measurements provided by high-resolution MS, the compositions of even large, complex glycans can easily be determined. When combined with a nano-LC separation, differentiation of structural isomers also becomes a possibility. These components, together, provide a comprehensive picture of biotherapeutic glycosylation. In this review, we provide an overview of MS-based analytical platform for glycomic characterization of EPO biotherapeutics and biosimilars.

• BMB Reports
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• v.54 no.6
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• pp.305-310
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• 2021

Cereblon (CRBN) is a multi-functional protein that acts as a substrate receptor of the E3 ligase complex and a molecular chaperone. While CRBN is proposed to function in mitochondria, its specific roles are yet to be established. Here, we showed that knockdown of CRBN triggers oxidative stress and calcium overload in mitochondria, leading to disruption of mitochondrial membrane potential. Notably, long-term CRBN depletion using PROteolysis TArgeting Chimera (PROTAC) induced irreversible mitochondrial dysfunction, resulting in cell death. Our collective findings indicate that CRBN is required for mitochondrial homeostasis in cells.

• Mass Spectrometry Letters
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• v.8 no.4
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• pp.69-78
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• 2017

Glycosylation, which is one of the most common post-translation modification (PTMs) of proteins, plays a variety of crucial roles in many cellular events and biotherapeutics. Recent advances have led to the development of various analytical methods employing a mass spectrometry for glycomic and glycoproteomic study. However, site-specific glycosylation analysis is still a relatively new area with high potential for technologies and method development. This review will cover current MS-based workflows and technologies for site-specific mapping of glycosylation ranging from glycopeptide preparation to MS analysis. Bioinformatic tools for comprehensive analysis of glycoprotein with high-throughput manner will be also included.

• Biomolecules & Therapeutics
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• v.26 no.1
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• pp.69-80
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• 2018

Cancer cells reprogram cellular metabolism to support the malignant features of tumors, such as rapid growth and proliferation. The cancer promoting effects of metabolic reprogramming are found in many aspects: generating additional energy, providing more anabolic molecules for biosynthesis, and rebalancing cellular redox states in cancer cells. Metabolic pathways are considered the pipelines to supply metabolic cofactors of epigenetic modifiers. In this regard, cancer metabolism, whereby cellular metabolite levels are greatly altered compared to normal levels, is closely associated with cancer epigenetics, which is implicated in many stages of tumorigenesis. In this review, we provide an overview of cancer metabolism and its involvement in epigenetic modifications and suggest that the metabolic adaptation leading to epigenetic changes in cancer cells is an important non-genetic factor for tumor progression, which cooperates with genetic causes. Understanding the interaction of metabolic reprogramming with epigenetics in cancers may help to develop novel or highly improved therapeutic strategies that target cancer metabolism.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.375-382
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• 2010

The available techniques for heterologous protein secretion in Lactobacillus strains are limited. The aim of the present study was to develop an efficient protein-secretion system using recombinant lactobacilli for various applications such as live delivery of biotherapeutics. For the construction of expression vectors, the Lactobacillus brevis slpA promoter, Lactobacillus casei prtP signal sequence, and mouse IL-10 sequences were used as a model system. Interestingly, the slpA promoter exhibited strong activity in L. casei, contrary to previous observations. In order to stabilize replication of the plasmid in E. coli, a removable terminator sequence was built into the promoter region. For the improvement of secretion efficiency, a DTNSD oligopeptide was added to the cleavage site of signal peptidase. The resulting plasmids provided remarkably efficient IL-10 secretion. Accumulation of the protein in the culture supernatant varied widely according to the pH conditions. By analysis of the secreted protein, formation of homodimers, and biological activity, IL-10 was confirmed to be functional. The presently constructed plasmids could be useful tools for heterologous protein secretion in L. casei.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.567-586
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• 2001

Gastrointestinal tract of ruminants as well as monogastric animals are colonised by a variety of microorganisms including bacteria, fungi and protozoa. Gastrointestinal ecosystem, especially the rumen is emerging as an important source for enrichment and natural selection of microbes adapted to specific conditions. It represents a virtually untapped source of novel products (e.g. enzymes, antibiotics, bacteriocins, detoxificants and aromatic compounds) for industrial and therapeutic applications. Several gastrointestinal bacteria and fungi implicated in detoxification of anti-nutritional factors (ANFs) can be modified and manipulated into promising system for detoxifying feed stuffs and enhancing fibre fermentation both naturally by adaptation or through genetic engineering techniques. Intestinal lactobacilli, bifidobacteria and butyrivibrios are being thoroughly investigated and widely recommended as probiotics. Restriction endonucleases and native plasmids, as stable vectors and efficient DNA delivery systems of ruminal and intestinal bacteria, are increasingly recognised as promising tools for genetic manipulation and development of industrially useful recombinant microbes. Enzymes can improve the nutrient availability from feed stuffs, lower feed costs and reduce release of wastes into the environment. Characterization of genes encoding a variety of commercially important enzymes such as cellulases, xylanases, $\beta$-glucanases, pectinases, amylases and phytases will foster the development of more efficacious and viable enzyme supplements and enzyme expression systems for enhancing livestock production.