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Jung Ho Lee,Brian H Lee,Soyoung Jeong,Christine Suh-Yun Joh,Hyo Jeong Nam,Hyun Seung Choi,Henry Sserwadda,Ji Won Oh,Chung-Gyu Park,Seon-Pil Jin,Hyun Je Kim Korea Genome Organization 2023 Genomics & informatics Vol.21 No.2
Immunologists have activated T cells in vitro using various stimulation methods, including phorbol myristate acetate (PMA)/ionomycin and αCD3/αCD28 agonistic antibodies. PMA stimulates protein kinase C, activating nuclear factor-κB, and ionomycin increases intracellular calcium levels, resulting in activation of nuclear factor of activated T cell. In contrast, αCD3/αCD28 agonistic antibodies activate T cells through ZAP-70, which phosphorylates linker for activation of T cell and SH2-domain-containing leukocyte protein of 76 kD. However, despite the use of these two different in vitro T cell activation methods for decades, the differential effects of chemical-based and antibody-based activation of primary human T cells have not yet been comprehensively described. Using single-cell RNA sequencing (scRNA-seq) technologies to analyze gene expression unbiasedly at the single-cell level, we compared the transcriptomic profiles of the non-physiological and physiological activation methods on human peripheral blood mononuclear cell-derived T cells from four independent donors. Remarkable transcriptomic differences in the expression of cytokines and their respective receptors were identified. We also identified activated CD4 T cell subsets (CD55<sup>+</sup>) enriched specifically by PMA/ionomycin activation. We believe this activated human T cell transcriptome atlas derived from two different activation methods will enhance our understanding, highlight the optimal use of these two in vitro T cell activation assays, and be applied as a reference standard when analyzing activated specific disease-originated T cells through scRNA-seq.
Jung Eun Lee,Christine Haewon Park,Hana Kang,Juyeon Ko,Suhan Cho,JooHan Woo,Mee Ree Chae,Sung Won Lee,Sung Joon Kim,Jinsung Kim,Insuk So 대한생리학회-대한약리학회 2020 The Korean Journal of Physiology & Pharmacology Vol.24 No.6
KCNQ family constitutes slowly-activating potassium channels among voltage-gated potassium channel superfamily. Recent studies suggested that KCNQ4 and 5 channels are abundantly expressed in smooth muscle cells, especially in lower urinary tract including corpus cavernosum and that both channels can exert membrane stabilizing effect in the tissues. In this article, we examined the electrophysiological characteristics of overexpressed KCNQ4, 5 channels in HEK293 cells with recently developed KCNQ-specific agonist. With submicromolar EC₅₀, the drug not only increased the open probability of KCNQ4 channel but also increased slope conductance of the channel. The overall effect of the drug in whole-cell configuration was to increase maximal whole-cell conductance, to prolongate the activation process, and left-shift of the activation curve. The agonistic action of the drug, however, was highly attenuated by the co-expression of one of the β ancillary subunits of KCNQ family, KCNE4. Strong in vitro interactions between KCNQ4, 5 and KCNE4 were found through Foster Resonance Energy Transfer and co-immunoprecipitation. Although the expression levels of both KCNQ4 and KCNE4 are high in mesenteric arterial smooth muscle cells, we found that 1 μM of the agonist was sufficient to almost completely relax phenylephrine-induced contraction of the muscle strip. Significant expression of KCNQ4 and KCNE4 in corpus cavernosum together with high tonic contractility of the tissue grants highly promising relaxational effect of the KCNQspecific agonist in the tissue.
Lee, Seoung Rak,Beemelmanns, Christine,Tsuma, Leah M. M.,Clardy, Jon,Cao, Shugeng,Kim, Ki Hyun NATURAL PRODUCT COMMUNICATIONS 2016 Natural product communications Vol.11 No.4
<P>Bacterially-produced small molecules demonstrate a wide range of structural and functional diversity. A new diketopiperazine, cyclo(D-trans-Hyp-L-Leu) (1), and five other known diketopiperazines (2-6), were isolated and purified from the fermented broth of a Kenyan bacterium Bacillus licheniformis LB 8C(T). The structure of 1 was elucidated by a combination of extensive spectroscopic analyses, including 2D NMR and HR-MS, and the absolute configuration was determined by a combination of NOESY analysis and Marfey's method. The known compounds were identified as cyclo(D-cis-Hyp-L-Leu) (2), cyclo(D-cis-Hyp-L-Phe) (3), cyclo(D-Pro-L-Tyr) (4), cyclo-(D-Trp-L-Leu) (5), and cyclo(L-Tyr-Gly) (6) by comparison of their spectroscopic and physical data with reported values. Compounds 1-6 were tested for antifungal and antimicrobial properties.</P>
Lee, Myung-Suk,Youn, Christine,Kim, Jeong Hyun,Park, Byoung Jun,Ahn, Jongchan,Hong, Sungyoul,Kim, Young-Deug,Shin, Young Kee,Park, Sang Gyu MDPI AG 2017 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.18 No.8
<P>The multipotency and anti-inflammatory effects of mesenchymal stem cells (MSCs) make them attractive for cell therapy in regenerative medicine. A large number of MSCs is required for efficient therapy owing to the low homing efficiency of MSCs to target sites. Furthermore, owing to limitations in obtaining sufficient amounts of MSCs, in vitro expansion of MSCs that preserves their differentiation and proliferative potential is essential. The animal factor included in culture media also limits clinical application. In this study, adipose-derived MSCs showed a significantly higher proliferation rate in STK2, a chemically-defined medium, than in DMEM/FBS. The expression of MSC surface markers was increased in the culture using STK2 compared to that using DMEM/FBS. Tri-lineage differentiation analyses showed that MSCs cultured in STK2 were superior to those cultured in DMEM/FBS. In addition, MSCs cultured in STK2 showed a reduced senescence rate, small and homogenous cell size, and were more genetically stable compared to those cultured in DMEM/FBS. Furthermore, secretome analysis showed that the expression of factors related to proliferation/migration, anti-inflammation, and differentiation were increased in STK2 culture medium compared to DMEM/FBS. Taken together, these results suggest that culture using STK2 medium offers many advantages through which it is possible to obtain safer, superior, and larger numbers of MSCs.</P>
Lee, Seoung Rak,Kü,fner, Michelle,Park, Minji,Jung, Won Hee,Choi, Sang Un,Beemelmanns, Christine,Kim, Ki Hyun The Royal Society of Chemistry 2019 ORGANIC CHEMISTRY FRONTIERS Vol.6 No.2
<P>We report the isolation of two novel epimeric phomaligadione-derived polyketides, beauvetetraones A-B (1-2), from the entomopathogenic fungus <I>Beauveria bassiana</I>. Beauvetetraones A and B feature an unprecedented methylene-bridged phloroglucinol skeleton with a highly rearranged scaffold. In addition, a dimer of two phomaligadiones, named beauvetetraone C, was isolated for the first time from a natural source. The structures of compounds 1-3 including their absolute configurations were unambiguously assigned by NMR spectroscopic analyses, phenylglycine methyl ester (PGME) analysis, and quantum chemical ECD calculations. A putative biosynthetic pathway for beauvetetraones A-C is proposed.</P>