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Meneksedag-Erol D, de Araujo ED, Erdogan F, Seo HS, Dhe-Paganon S, Gunning PT, Rauscher S. Uncovering the Molecular Basis for the Clinical N642H Mutation in STAT5B Using Atomistic Molecular Simulations. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Kozono S, Lin YM, Seo HS, Pinch B, Lian X, Qiu C, Herbert MK, Chen CH, Tan L, Gao ZJ, Massefski W, Doctor ZM, Jackson BP, Chen Y, Dhe-Paganon S, Lu KP, Zhou XZ. Arsenic targets Pin1 and cooperates with retinoic acid to inhibit cancer-driving pathways and tumor-initiating cells. Nat Commun 2018; 9:3069. [PMID: 30093655 PMCID: PMC6085299 DOI: 10.1038/s41467-018-05402-2] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/05/2018] [Indexed: 12/27/2022] Open
Abstract
Arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) combination safely cures fatal acute promyelocytic leukemia, but their mechanisms of action and efficacy are not fully understood. ATRA inhibits leukemia, breast, and liver cancer by targeting isomerase Pin1, a master regulator of oncogenic signaling networks. Here we show that ATO targets Pin1 and cooperates with ATRA to exert potent anticancer activity. ATO inhibits and degrades Pin1, and suppresses its oncogenic function by noncovalent binding to Pin1's active site. ATRA increases cellular ATO uptake through upregulating aquaporin-9. ATO and ATRA, at clinically safe doses, cooperatively ablate Pin1 to block numerous cancer-driving pathways and inhibit the growth of triple-negative breast cancer cells and tumor-initiating cells in cell and animal models including patient-derived orthotopic xenografts, like Pin1 knockout, which is substantiated by comprehensive protein and microRNA analyses. Thus, synergistic targeting of Pin1 by ATO and ATRA offers an attractive approach to combating breast and other cancers.
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Rha SW, Choi BG, Choi SY, Byun JK, Hong JY, Park JY, Park SH, Choi CU, Park CG, Seo HS. P281Impact of anemia on development of new-onset diabetes mellitus and 5-year major clinical outcomes in the korean population. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy564.p281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Kim YH, Her AY, Rha SW, Choi BG, Mashaly A, Park Y, Jang WY, Kim W, Choi JY, Park EJ, Na JO, Choi CU, Kim EJ, Park CG, Seo HS. P5534Three-year major clinical outcomes of phosphorylcholine polymer- versus BioLinx polymer-zotarolimus-eluting stents: A propensity score matching study. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy566.p5534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kim YH, Her AY, Rha SW, Choi BG, Mashaly A, Park Y, Jang WY, Kim W, Choi JY, Park EJ, Na JO, Choi CU, Kim EJ, Park CG, Seo HS. 119Angiotensin converting enzyme inhibitor versus angiotensin receptor blockers on the top of calcium channel blocker in development of new-onset diabetes mellitus in hypertensive Korean patients. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy564.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Rha SW, Choi BG, Choi SY, Byun JK, Hong JY, Park JY, Park SH, Choi CU, Park CG, Seo HS. P282Application of machine learning for predicting new-onset diabetes mellitus during 5-year follow-up in non-diabetic patients with cardiovascular risk. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy564.p282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kim YH, Her AY, Rha SW, Choi BG, Mashaly A, Park Y, Jang WY, Kim W, Choi JY, Park EJ, Na JO, Choi CU, Kim EJ, Park CG, Seo HS. P3209Calcium channel blocker monotherapy versus combination with renin-angiotensin system blockers in the development of new-onset diabetes mellitus in hypertensive Korean patients. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p3209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Park EJ, Eo JS, Jang WY, Na JO, Choi CU, Kim EJ, Rha SW, Park CG, Seo HS, Kim JW. P1689Association of brain amygdalar activity with plaque burden and vulnerability in coronary artery. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy565.p1689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Park EJ, Kim WH, Choi JY, Jang WY, Na JO, Choi JI, Kim JW, Kim EJ, Rha SW, Park CG, Seo HS, Choi CU. P2690The bleeding and cardiovascular risk according to NSAIDs selectivity in patients receiving antithrombotics and concomitant NSAIDs after myocardial infarction: a nationwide cohort study. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy565.p2690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Rha SW, Byun JK, Choi BG, Choi SY, Hong JY, Park JY, Park SH, Choi CU, Park CG, Seo HS. P3623Impact of blood urea nitrogen/creatinine ratio in coronary artery disease patients underwent successful percutaneous coronary intervention with drug eluting stents: 5-year follow-up results. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p3623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Rha SW, Mashaly A, Choi BG, Choi SY, Byun JK, Hong JY, Park JY, Park SH, Choi CU, Park CG, Seo HS. P1636Impact of uric acid on 5-year clinical outcomes after below-the-knee endovascular intervention. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy565.p1636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Harvey EP, Seo HS, Guerra RM, Bird GH, Dhe-Paganon S, Walensky LD. Abstract 1901: Structural basis for selective therapeutic targeting of BFL-1 in cancer by a covalent stapled peptide inhibitor. Cancer Res 2018. [DOI: 10.1158/1538-7445.am2018-1901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
BCL-2 family proteins are master regulators of the mitochondrial apoptotic pathway and dictate whether a cell will live or die in response to stress. Cancer cells hijack the anti-apoptotic arm of this signaling network, overexpressing BCL-2, MCL-1, and BFL-1, to enforce cellular immortality. Whereas BCL-2 has been drugged by the selective small-molecule inhibitor, venetoclax, and new MCL-1 inhibitor molecules have just entered phase I clinical testing, anti-apoptotic BFL-1 remains undrugged. Importantly, the expression of BFL-1 can cause resistance to these molecules and has been independently linked to the pathogenesis and chemoresistance of human cancers, including melanomas and hematologic malignancies. Given the emergence of BCL-2 family proteins as high-priority cancer targets, solving their structures, alone and in complex with their natural BH3 domain ligands, yields important blueprints for drug design. Whereas the structures of numerous “BH3-in-groove” complexes have been solved, the corresponding panel of apo structures remains incomplete. Here, we report the crystal structure of apo BFL-1 at 1.69 Å resolution, revealing similarities and key differences among unliganded anti-apoptotic targets. Unlike all other BCL-2 proteins, apo BFL-1 contains a surface-accessible cysteine within its BH3-binding groove, allowing for selective covalent targeting by BH3-based stapled peptide inhibitors. The crystal structure of a complex between BFL-1 and a cysteine-reactive and stapled NOXA BH3 α-helix demonstrated the sulfhydryl bond and fortuitous interactions between the acrylamide-bearing moiety and a newly formed hydrophobic cavity. Comparison of the apo and BH3-liganded structures further revealed an induced conformational change. The two BFL-1 structures expand our understanding of the surface landscapes available for selective targeting of BFL-1, and inform a new therapeutic strategy for overcoming BFL-1-dependent apoptotic blockades in human cancer.
Citation Format: Edward P. Harvey, Hyuk-Soo Seo, Rachel M. Guerra, Gregory H. Bird, Sirano Dhe-Paganon, Loren D. Walensky. Structural basis for selective therapeutic targeting of BFL-1 in cancer by a covalent stapled peptide inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1901.
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Harvey EP, Seo HS, Guerra RM, Bird GH, Dhe-Paganon S, Walensky LD. Crystal Structures of Anti-apoptotic BFL-1 and Its Complex with a Covalent Stapled Peptide Inhibitor. Structure 2017; 26:153-160.e4. [PMID: 29276033 DOI: 10.1016/j.str.2017.11.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 10/25/2017] [Accepted: 11/17/2017] [Indexed: 01/08/2023]
Abstract
BCL-2 family proteins are high-priority cancer targets whose structures provide essential blueprints for drug design. Whereas numerous structures of anti-apoptotic BCL-2 protein complexes with α-helical BH3 peptides have been reported, the corresponding panel of apo structures remains incomplete. Here, we report the crystal structure of apo BFL-1 at 1.69-Å resolution, revealing similarities and key differences among unliganded anti-apoptotic proteins. Unlike all other BCL-2 proteins, apo BFL-1 contains a surface-accessible cysteine within its BH3-binding groove, allowing for selective covalent targeting by a NOXA BH3-based stapled peptide inhibitor. The crystal structure of this complex demonstrated the sulfhydryl bond and fortuitous interactions between the acrylamide-bearing moiety and a newly formed hydrophobic cavity. Comparison of the apo and BH3-liganded structures further revealed an induced conformational change. The two BFL-1 structures expand our understanding of the surface landscapes available for therapeutic targeting so that the apoptotic blockades of BFL-1-dependent cancers can be overcome.
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Lamberto I, Liu X, Seo HS, Schauer NJ, Iacob RE, Hu W, Das D, Mikhailova T, Weisberg EL, Engen JR, Anderson KC, Chauhan D, Dhe-Paganon S, Buhrlage SJ. Structure-Guided Development of a Potent and Selective Non-covalent Active-Site Inhibitor of USP7. Cell Chem Biol 2017; 24:1490-1500.e11. [PMID: 29056421 DOI: 10.1016/j.chembiol.2017.09.003] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/09/2017] [Accepted: 09/05/2017] [Indexed: 01/30/2023]
Abstract
Deubiquitinating enzymes (DUBs) have garnered significant attention as drug targets in the last 5-10 years. The excitement stems in large part from the powerful ability of DUB inhibitors to promote degradation of oncogenic proteins, especially proteins that are challenging to directly target but which are stabilized by DUB family members. Highly optimized and well-characterized DUB inhibitors have thus become highly sought after tools. Most reported DUB inhibitors, however, are polypharmacological agents possessing weak (micromolar) potency toward their primary target, limiting their utility in target validation and mechanism studies. Due to a lack of high-resolution DUB⋅small-molecule ligand complex structures, no structure-guided optimization efforts have been reported for a mammalian DUB. Here, we report a small-molecule⋅ubiquitin-specific protease (USP) family DUB co-structure and rapid design of potent and selective inhibitors of USP7 guided by the structure. Interestingly, the compounds are non-covalent active-site inhibitors.
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Huang HT, Seo HS, Zhang T, Wang Y, Jiang B, Li Q, Buckley DL, Nabet B, Roberts JM, Paulk J, Dastjerdi S, Winter GE, McLauchlan H, Moran J, Bradner JE, Eck MJ, Dhe-Paganon S, Zhao JJ, Gray NS. MELK is not necessary for the proliferation of basal-like breast cancer cells. eLife 2017; 6. [PMID: 28926338 PMCID: PMC5605198 DOI: 10.7554/elife.26693] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 08/18/2017] [Indexed: 01/22/2023] Open
Abstract
Thorough preclinical target validation is essential for the success of drug discovery efforts. In this study, we combined chemical and genetic perturbants, including the development of a novel selective maternal embryonic leucine zipper kinase (MELK) inhibitor HTH-01-091, CRISPR/Cas9-mediated MELK knockout, a novel chemical-induced protein degradation strategy, RNA interference and CRISPR interference to validate MELK as a therapeutic target in basal-like breast cancers (BBC). In common culture conditions, we found that small molecule inhibition, genetic deletion, or acute depletion of MELK did not significantly affect cellular growth. This discrepancy to previous findings illuminated selectivity issues of the widely used MELK inhibitor OTSSP167, and potential off-target effects of MELK-targeting short hairpins. The different genetic and chemical tools developed here allow for the identification and validation of any causal roles MELK may play in cancer biology, which will be required to guide future MELK drug discovery efforts. Furthermore, our study provides a general framework for preclinical target validation.
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Remillard D, Buckley DL, Paulk J, Brien GL, Sonnett M, Seo HS, Dastjerdi S, Wühr M, Dhe-Paganon S, Armstrong SA, Bradner JE. Degradation of the BAF Complex Factor BRD9 by Heterobifunctional Ligands. Angew Chem Int Ed Engl 2017; 56:5738-5743. [PMID: 28418626 DOI: 10.1002/anie.201611281] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 02/24/2017] [Indexed: 12/12/2022]
Abstract
The bromodomain-containing protein BRD9, a subunit of the human BAF (SWI/SNF) nucleosome remodeling complex, has emerged as an attractive therapeutic target in cancer. Despite the development of chemical probes targeting the BRD9 bromodomain, there is a limited understanding of BRD9 function beyond acetyl-lysine recognition. We have therefore created the first BRD9-directed chemical degraders, through iterative design and testing of heterobifunctional ligands that bridge the BRD9 bromodomain and the cereblon E3 ubiquitin ligase complex. Degraders of BRD9 exhibit markedly enhanced potency compared to parental ligands (10- to 100-fold). Parallel study of degraders with divergent BRD9-binding chemotypes in models of acute myeloid leukemia resolves bromodomain polypharmacology in this emerging drug class. Together, these findings reveal the tractability of non-BET bromodomain containing proteins to chemical degradation, and highlight lead compound dBRD9 as a tool for the study of BRD9.
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Remillard D, Buckley DL, Paulk J, Brien GL, Sonnett M, Seo HS, Dastjerdi S, Wühr M, Dhe-Paganon S, Armstrong SA, Bradner JE. Degradation of the BAF Complex Factor BRD9 by Heterobifunctional Ligands. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611281] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Ficarro SB, Browne CM, Card JD, Alexander WM, Zhang T, Park E, McNally R, Dhe-Paganon S, Seo HS, Lamberto I, Eck MJ, Buhrlage SJ, Gray NS, Marto JA. Leveraging Gas-Phase Fragmentation Pathways for Improved Identification and Selective Detection of Targets Modified by Covalent Probes. Anal Chem 2016; 88:12248-12254. [PMID: 28193034 DOI: 10.1021/acs.analchem.6b03394] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The recent approval of covalent inhibitors for multiple clinical indications has reignited enthusiasm for this class of drugs. As interest in covalent drugs has increased, so too has the need for analytical platforms that can leverage their mechanism-of-action to characterize modified protein targets. Here we describe novel gas phase dissociation pathways which yield predictable fragment ions during MS/MS of inhibitor-modified peptides. We find that these dissociation pathways are common to numerous cysteine-directed probes as well as the covalent drugs, Ibrutinib and Neratinib. We leverage the predictable nature of these fragment ions to improve the confidence of peptide sequence assignment in proteomic analyses and explore their potential use in selective mass spectrometry-based assays.
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Tanaka M, Roberts JM, Seo HS, Souza A, Paulk J, Scott TG, DeAngelo SL, Dhe-Paganon S, Bradner JE. Design and characterization of bivalent BET inhibitors. Nat Chem Biol 2016; 12:1089-1096. [PMID: 27775715 PMCID: PMC5117811 DOI: 10.1038/nchembio.2209] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 08/02/2016] [Indexed: 12/24/2022]
Abstract
Cellular signaling is often propagated by multivalent interactions. Multivalency creates avidity, allowing stable biophysical recognition. Multivalency is an attractive strategy for achieving potent binding to protein targets, as the affinity of bivalent ligands is often greater than the sum of monovalent affinities. The BET family of transcriptional coactivators features tandem bromodomains, through which BET proteins naturally bind acetylated histones and transcription factors. All reported BRD4 antagonists bind in a monovalent fashion. Here, we report the first bivalent BET bromodomain inhibitor, MT1 that has unprecedented potency. Biophysical and biochemical studies suggest MT1 is an intramolecular bivalent BRD4 binder that is over 100-fold more potent in cellular assays compared to the corresponding monovalent antagonist, JQ1. MT1 significantly delayed leukemia progression in mice (Mus musculus) compared to JQ1. These data qualify a powerful chemical probe for BET bromodomains and extensible rationale for further development of multidomain epigenetic reader protein inhibitors.
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Chung SM, Hyun MH, Lee E, Seo HS. Novel effects of sarcopenic osteoarthritis on metabolic syndrome, insulin resistance, osteoporosis, and bone fracture: the national survey. Osteoporos Int 2016; 27:2447-57. [PMID: 27177746 DOI: 10.1007/s00198-016-3548-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 02/19/2016] [Indexed: 12/14/2022]
Abstract
UNLABELLED This study compared the effects sarcopenic osteoarthritis on metabolic syndrome, insulin resistance, osteoporosis, and bone fracture. By using national survey data, we suggest that the relationship between sarcopenia and metabolic syndrome or insulin resistance is potentiated by the severity of osteoarthritis and is independent of body weight. INTRODUCTION Sarcopenia and osteoarthritis are known risk factors for metabolic syndrome. However, their combined effects on metabolic syndrome, insulin resistance and osteoporosis remain uncertain. METHODS We used data from the fifth Korean National Health and Nutrition Examination Survey using a total of 3158 adults (age >50 years). Sarcopenia was defined as a skeletal muscle index score (appendicular skeletal muscle mass/body weight) within the fifth percentile of sex-matched younger reference participants. Radiographic knee osteoarthritis was defined as a Kellgren-Lawrence (K-L) grade of 2 or greater. Metabolic syndrome was diagnosed using the National Cholesterol Education Program criteria. Insulin resistance was evaluated using the homeostasis model assessment-estimated insulin resistance index (HOMA-IR). Osteoporosis was defined using the World Health Organization T-score criteria. RESULTS In multivariable logistic regression analysis, the sarcopenic osteoarthritis group had a higher odds ratio (OR) for metabolic syndrome (OR = 11.00, 95 % confidential interval (CI) = 2.12-56.99, p = 0.013) than the non-sarcopenic osteoarthritis (OR = 1.02, 95 % CI = 0.65-1.62, p = 0.972) and sarcopenic non-osteoarthritis groups (OR = 7.15, 95 % CI = 1.57-32.53, p = 0.027). Similarly, sarcopenic osteoarthritis had a greater OR of highest HOMA-IR quartiles (OR = 8.19, 95 % CI = 2.03-33.05, p = 0.003) than the other groups. Overall, the association between the K-L grade and body mass index was significant; however, this significance was lower in individuals with sarcopenia and was lost in those with sarcopenic osteoarthritis. Additionally, osteoporosis and bone fracture were not associated to sarcopenic osteoarthritis (p > 0.05). CONCLUSIONS These results suggest that the relationship between sarcopenia and metabolic syndrome or insulin resistance is potentiated by the severity of osteoarthritis and is independent of body weight.
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Seo HS, Kim YJ. Effect of electrode positions on the mixing characteristics of an electroosmotic micromixer. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2014; 14:6167-6171. [PMID: 25936080 DOI: 10.1166/jnn.2014.8802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this study, an electrokinetic microchannel with a ring-type mixing chamber is introduced for fast mixing. The modeled micromixer that is used for the study of the electroosmotic effect takes two fluids from different inlets and combines them in a ring-type mixing chamber and, then, they are mixed by the electric fields at the electrodes. In order to compare the mixing performance in the modeled micromixer, we numerically investigated the flow characteristics with different positions of the electrodes in the mixing chamber using the commercial code, COMSOL. In addition, we discussed the concentration distributions of the dissolved substances in the flow fields and compared the mixing efficiency in the modeled micromixer with different electrode positions and operating conditions, such as the frequencies and electric potentials at the electrodes.
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Kim YK, Seo HS, Lee EM, Na JO, Choi CU, Lim HE, Kim EJ, Rha SW, Park CG, Oh DJ. Association of hypertension with small, dense low-density lipoprotein in patients without metabolic syndrome. J Hum Hypertens 2011; 26:670-6. [PMID: 21975689 DOI: 10.1038/jhh.2011.86] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A higher proportion of small, dense low-density lipoprotein (sdLDL) is known to be associated with a high prevalence of cardiovascular disease in association with metabolic syndrome (MS). Hypertension (HTN) is one of the known risk factors for MS. However, whether HTN is associated with sdLDL in patients without MS is not yet clear. The lipid profiles, including low-density-lipoprotein (LDL) subfractions, of 383 consecutive subjects were evaluated. The patients without MS consisted of 198 hypertensive patients (non-MS/HTN group) and 108 normotensive subjects (non-MS/non-HTN group). The peak and mean particle diameter of LDL were measured by gradient gel electrophoresis. Plasma total cholesterol, LDL cholesterol, high-density lipoprotein (HDL) cholesterol, triglyceride (TG), HDL cholesterol/Apo A1, LDL-C/ApoB and Apo(A1, B, CII and E) levels did not differ between the non-MS/non-HTN and non-MS/HTN groups. When analyzing LDL subfraction, the absolute amount of patterns A and B was not different between the non-MS/non-HTN and non-MS/HTN groups. Compared with the non-MS/non-HTN groups, the proportion of sdLDL was higher in the non-MS/HTN group (37.7% versus 39.9%, P=0.046), but not significant after adjustment of waist circumference, serum TG, age and statin usage. The proportion of sdLDL to total LDL was higher in hypertensive subjects, even those without MS, than in normotensive subjects. However, this difference of LDL subfraction in hypertensive patients is associated with higher waist circumference, higher serum TG, older age and more statin usage. This result suggests that HTN may contribute to atherosclerosis and endothelial dysfunction with associated risk factors that influence LDL size.
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Roh JH, Kim JB, Seo HS, Kwon DY, Park MH. Teaching NeuroImages: posterior cerebral artery susceptibility vessel sign on T2*-weighted gradient echo imaging. Neurology 2011; 77:e25. [PMID: 21788615 DOI: 10.1212/wnl.0b013e3182267b60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Seo HS, Na DG, Kim JH, Kim KW, Son KR. Correlation between CT and diffusion-weighted imaging of acute cerebral ischemia in a rat model. AJNR Am J Neuroradiol 2011; 32:728-33. [PMID: 21330394 DOI: 10.3174/ajnr.a2362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The quantitative temporal relationship between changes in CT attenuation, ADC value, and DWI signal intensity of acute ischemic tissue has not yet been determined in an animal model. This study was performed to determine the temporal relationship between CT attenuation, ADC value, and DWI signal intensity in acute cerebral ischemia. MATERIALS AND METHODS CT and DWI were performed at 1, 3, 5, 7, and 9 hours after left MCA occlusion in 11 rats. Mean values for CT attenuation, ADC, and DWI signal intensity were determined for the ischemic hemisphere and contralateral normal hemisphere. Temporal changes in each mean value and the relationship between CT attenuation and ADC value and DWI signal intensity were evaluated. RESULTS The decrease of CT attenuation and the increase of DWI signal intensity occurred gradually after MCA occlusion, while ADC value decreased rapidly at 1 hour. Although correlation was significant between time and rCT or rDWI (P<.01, respectively), no correlation between time and rADC was found (P=.33). There was a significant linear correlation between rCT and rDWI (r=0.497, P<.01), but no significant correlation between rCT and rADC (P=.509) was found. CONCLUSIONS The temporal change in CT attenuation was different from that in ADC value with no significant linear correlation between CT attenuation and ADC value for acute cerebral ischemia. However, rCT and rDWI showed a modest correlation.
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Debler EW, Hsia KC, Nagy V, Seo HS, Hoelz A. Characterization of the membrane-coating Nup84 complex. Nucleus 2010. [DOI: 10.4161/nucl.11120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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