Asan Institute of Life Science

Seoul, South Korea

Asan Institute of Life Science

Seoul, South Korea
SEARCH FILTERS
Time filter
Source Type

Inceoglu B.,University of California at Davis | Zolkowska D.,University of California at Davis | Yoo H.J.,Asan Institute of Life science | Wagner K.M.,University of California at Davis | And 7 more authors.
PLoS ONE | Year: 2013

In the brain, seizures lead to release of large amounts of polyunsaturated fatty acids including arachidonic acid (ARA). ARA is a substrate for three major enzymatic routes of metabolism by cyclooxygenase, lipoxygenase and cytochrome P450 enzymes. These enzymes convert ARA to potent lipid mediators including prostanoids, leukotrienes and epoxyeicosatrienoic acids (EETs). The prostanoids and leukotrienes are largely pro-inflammatory molecules that sensitize neurons whereas EETs are anti-inflammatory and reduce the excitability of neurons. Recent evidence suggests a GABA-related mode of action potentially mediated by neurosteroids. Here we tested this hypothesis using models of chemically induced seizures. The level of EETs in the brain was modulated by inhibiting the soluble epoxide hydrolase (sEH), the major enzyme that metabolizes EETs to inactive molecules, by genetic deletion of sEH and by direct administration of EETs into the brain. All three approaches delayed onset of seizures instigated by GABA antagonists but not seizures through other mechanisms. Inhibition of neurosteroid synthesis by finasteride partially blocked the anticonvulsant effects of sEH inhibitors while the efficacy of an inactive dose of neurosteroid allopregnanolone was enhanced by sEH inhibition. Consistent with earlier findings, levels of prostanoids in the brain were elevated. In contrast, levels of bioactive EpFAs were decreased following seizures. Overall these results demonstrate that EETs are natural molecules which suppress the tonic component of seizure related excitability through modulating the GABA activity and that exploration of the EET mediated signaling in the brain could yield alternative approaches to treat convulsive disorders.


PubMed | Asan Institute of Life science and University of California at Davis
Type: Journal Article | Journal: PloS one | Year: 2013

In the brain, seizures lead to release of large amounts of polyunsaturated fatty acids including arachidonic acid (ARA). ARA is a substrate for three major enzymatic routes of metabolism by cyclooxygenase, lipoxygenase and cytochrome P450 enzymes. These enzymes convert ARA to potent lipid mediators including prostanoids, leukotrienes and epoxyeicosatrienoic acids (EETs). The prostanoids and leukotrienes are largely pro-inflammatory molecules that sensitize neurons whereas EETs are anti-inflammatory and reduce the excitability of neurons. Recent evidence suggests a GABA-related mode of action potentially mediated by neurosteroids. Here we tested this hypothesis using models of chemically induced seizures. The level of EETs in the brain was modulated by inhibiting the soluble epoxide hydrolase (sEH), the major enzyme that metabolizes EETs to inactive molecules, by genetic deletion of sEH and by direct administration of EETs into the brain. All three approaches delayed onset of seizures instigated by GABA antagonists but not seizures through other mechanisms. Inhibition of neurosteroid synthesis by finasteride partially blocked the anticonvulsant effects of sEH inhibitors while the efficacy of an inactive dose of neurosteroid allopregnanolone was enhanced by sEH inhibition. Consistent with earlier findings, levels of prostanoids in the brain were elevated. In contrast, levels of bioactive EpFAs were decreased following seizures. Overall these results demonstrate that EETs are natural molecules which suppress the tonic component of seizure related excitability through modulating the GABA activity and that exploration of the EET mediated signaling in the brain could yield alternative approaches to treat convulsive disorders.


Kim G.B.,Asan Institute of Life Science | Lee S.,Asan Institute of Life Science | Kim H.,Asan Institute of Life Science | Yang D.H.,University of Ulsan | And 8 more authors.
Korean Journal of Radiology | Year: 2016

The advent of three-dimensional printing (3DP) technology has enabled the creation of a tangible and complex 3D object that goes beyond a simple 3D-shaded visualization on a flat monitor. Since the early 2000s, 3DP machines have been used only in hard tissue applications. Recently developed multi-materials for 3DP have been used extensively for a variety of medical applications, such as personalized surgical planning and guidance, customized implants, biomedical research, and preclinical education. In this review article, we discuss the 3D reconstruction process, touching on medical imaging, and various 3DP systems applicable to medicine. In addition, the 3DP medical applications using multi-materials are introduced, as well as our recent results. © 2016 The Korean Society of Radiology.


PubMed | University of Ulsan, Asan Institute of Life Science and Pohang University of Science and Technology
Type: Journal Article | Journal: Korean journal of radiology | Year: 2016

The advent of three-dimensional printing (3DP) technology has enabled the creation of a tangible and complex 3D object that goes beyond a simple 3D-shaded visualization on a flat monitor. Since the early 2000s, 3DP machines have been used only in hard tissue applications. Recently developed multi-materials for 3DP have been used extensively for a variety of medical applications, such as personalized surgical planning and guidance, customized implants, biomedical research, and preclinical education. In this review article, we discuss the 3D reconstruction process, touching on medical imaging, and various 3DP systems applicable to medicine. In addition, the 3DP medical applications using multi-materials are introduced, as well as our recent results.


PubMed | Ewha Womans University, Korea University, Asan Institute of Life science, Asan Medical Center and A-Life Medical
Type: | Journal: Database : the journal of biological databases and curation | Year: 2016

Kawasaki disease (KD) is a rare disease that occurs predominantly in infants and young children. To identify KD susceptibility genes and to develop a diagnostic test, a specific therapy, or prevention method, collecting KD patients clinical and genomic data is one of the major issues. For this purpose, Kawasaki Disease Database (KDD) was developed based on the efforts of Korean Kawasaki Disease Genetics Consortium (KKDGC). KDD is a collection of 1292 clinical data and genomic samples of 1283 patients from 13 KKDGC-participating hospitals. Each sample contains the relevant clinical data, genomic DNA and plasma samples isolated from patients blood, omics data and KD-associated genotype data. Clinical data was collected and saved using the common data elements based on the ISO/IEC 11179 metadata standard. Two genome-wide association study data of total 482 samples and whole exome sequencing data of 12 samples were also collected. In addition, KDD includes the rare cases of KD (16 cases with family history, 46 cases with recurrence, 119 cases with intravenous immunoglobulin non-responsiveness, and 52 cases with coronary artery aneurysm). As the first public database for KD, KDD can significantly facilitate KD studies. All data in KDD can be searchable and downloadable. KDD was implemented in PHP, MySQL and Apache, with all major browsers supported.Database URL: http://www.kawasakidisease.kr.


PubMed | University of Ulsan and Asan Institute of Life science
Type: | Journal: PeerJ | Year: 2015

Background. The objective of this study is to propose the four conditions for the roles of honest brokers through a review of literature published by ten institutions that are successfully utilizing honest brokers. Furthermore, the study aims to examine whether the Asan Medical Centers (AMC) honest brokers satisfy the four conditions, and examine the need to enhance their roles. Methods. We analyzed the roles, tasks, and types of honest brokers at 10 organizations by reviewing the literature. We also established a Task Force (TF) in our institution for setting the roles and processes of the honest broker system and the honest brokers. The findings of the literature search were compared with the existing systems at AMC-which introduced the honest broker system for the first time in Korea. Results. Only one organization employed an honest broker for validating anonymized clinical data and monitoring the anonymity verifications of the honest broker system. Six organizations complied with HIPAA privacy regulations, while four organizations did not disclose compliance. By comparing functions with those of the AMC, the following four main characteristics of honest brokers were determined: (1) de-identification of clinical data; (2) independence; (3) checking that the data are used only for purposes approved by the IRB; and (4) provision of de-identified data to researchers. These roles were then compared with those of honest brokers at the AMC. Discussion. First, guidelines that regulate the definitions, purposes, roles, and requirements for honest brokers are needed, since there are no currently existing regulations. Second, Korean clinical research institutions and national regulatory departments need to reach a consensus on a Korean version of Limited Data Sets (LDS), since there are no lists that describe the use of personal identification information. Lastly, satisfaction surveys on honest brokers by researchers are necessary to improve the quality of honest brokers.


Kwon H.-S.,University of Ulsan | Kim T.-B.,University of Ulsan | Lee Y.S.,University of Ulsan | Jeong S.-H.,University of Ulsan | And 5 more authors.
Annals of Allergy, Asthma and Immunology | Year: 2014

Background Oxidative stress is thought to play a role in the pathogenesis of asthma. Clusterin is a sensitive cellular biosensor of oxidative stress and has antioxidant properties. The function and expression of clusterin in patients with asthma have not been fully investigated. Objective To investigate whether the expression of clusterin in patients with asthma is regulated by increased oxidative burden and whether clusterin expression could be used to assess the response to inhaled corticosteroids. Methods Clusterin levels in serum, induced sputum, and peripheral blood mononuclear cells of patients with asthma were measured by enzyme-linked immunosorbent assay and western blotting and compared with pulmonary function and levels of expression of hyperoxidized peroxiredoxins. Serum concentrations of clusterin in treatment-naive patients were compared before and after inhaled corticosteroid use. Results Serum clusterin concentration was significantly elevated in patients with severe asthma and was inversely correlated with pulmonary function. The expression of hyperoxidized peroxiredoxins was greatly increased in peripheral blood mononuclear cells of patients with asthma and was strongly correlated with clusterin expression. Serum clusterin concentrations in treatment-naive patients with asthma were decreased significantly after initial treatment with inhaled corticosteroids. Conclusion Clusterin may be a biomarker of asthma severity and the burden of oxidative stress in patients with asthma. Moreover, clusterin may be useful for the prompt assessment of airway inflammation. © 2014 American College of Allergy, Asthma & Immunology.


Takeuchi C.S.,Exelixis | Kim B.G.,Exelixis | Kim B.G.,Asan Institute of Life Science | Blazey C.M.,Exelixis | And 27 more authors.
Journal of Medicinal Chemistry | Year: 2013

A series of novel, highly potent, selective, and ATP-competitive mammalian target of rapamycin (mTOR) inhibitors based on a benzoxazepine scaffold have been identified. Lead optimization resulted in the discovery of inhibitors with low nanomolar activity and greater than 1000-fold selectivity over the closely related PI3K kinases. Compound 28 (XL388) inhibited cellular phosphorylation of mTOR complex 1 (p-p70S6K, pS6, and p-4E-BP1) and mTOR complex 2 (pAKT (S473)) substrates. Furthermore, this compound displayed good pharmacokinetics and oral exposure in multiple species with moderate bioavailability. Oral administration of compound 28 to athymic nude mice implanted with human tumor xenografts afforded significant and dose-dependent antitumor activity. © 2013 American Chemical Society.


Jeon M.J.,University of Ulsan | Kim W.G.,University of Ulsan | Lim S.,Asan Institute of Life science | Choi H.-J.,Asan Institute of Life science | And 4 more authors.
Molecular and Cellular Endocrinology | Year: 2016

The naturally occurring short-chain fatty acid, α-lipoic acid (ALA) is a powerful antioxidant which is clinically used for treatment of diabetic neuropathy. Recent studies suggested the possibility of ALA as a potential anti-cancer agent, because it could activate adenosine monophosphate activated protein kinase (AMPK) and inhibit transforming growth factor-β (TGFβ) pathway. In this study, we evaluate the effects of ALA on thyroid cancer cell proliferation, migration and invasion. We performed in vitro cell proliferation analysis using BCPAP, HTH-83, CAL-62 and FTC-133 cells. ALA suppressed thyroid cancer cell proliferation through activation of AMPK and subsequent down-regulation of mammalian target of rapamycin (mTOR)-S6 signaling pathway. Low-dose ALA, which had minimal effects on cell proliferation, also decreased cell migration and invasion of BCPAP, CAL-62 and HTH-83 cells. ALA inhibited epithelial mesenchymal transition (EMT) evidently by increase of E-cadherin and decreases of activated β-catenin, vimentin, snail, and twist in these cells. ALA suppressed TGFβ production and inhibited induction of p-Smad2 and twist by TGFβ1 or TGFβ2. These findings indicate that ALA reduces cancer cell migration and invasion through suppression of TGFβ production and inhibition of TGFβ signaling pathways in thyroid cancer cells. ALA also significantly suppressed tumor growth in mouse xenograft model using BCPAP and FTC-133 cells. This is the first study to show anti-cancer effect of ALA on thyroid cancer cells. ALA could be a potential therapeutic agent for treatment of advanced thyroid cancer, possibly as an adjuvant therapy with other systemic therapeutic agents. © 2015 Elsevier Ireland Ltd.

Loading Asan Institute of Life Science collaborators
Loading Asan Institute of Life Science collaborators