https://scholar.dgist.ac.kr/handle/20.500.11750/341 2026-04-04T14:20:20Z 2026-04-04T14:20:20Z Lee, Se-In Jeong, Woojin Lim, Heejin Cho, Sukhee Lee, Hyein Jang, Yonghee Cho, Joonho Bae, Simsung Lin, Yuan-Ta Tsai, Li-Huei Moon, Dae Won Seo, Jinsoo https://scholar.dgist.ac.kr/handle/20.500.11750/15598 2025-07-25T04:10:16Z 2021-08-31T15:00:00Z

Title: APOE4-carrying human astrocytes oversupply cholesterol to promote neuronal lipid raft expansion and Aβ generation Author(s): Lee, Se-In; Jeong, Woojin; Lim, Heejin; Cho, Sukhee; Lee, Hyein; Jang, Yonghee; Cho, Joonho; Bae, Simsung; Lin, Yuan-Ta; Tsai, Li-Huei; Moon, Dae Won; Seo, Jinsoo Abstract: The epsilon 4 allele of APOE-encoding apolipoprotein (ApoE) is one of the strongest genetic risk factors for Alzheimer's disease (AD). One of the overarching questions is whether and how this astrocyte-enriched risk factor initiates AD-associated pathology in neurons such as amyloid-B (AB) accumulation. Here, we generate neurons and astrocytes from isogenic human induced pluripotent stem cells (hiPSCs) carrying either APOE epsilon 3 or APOE epsilon 4 allele and investigate the effect of astrocytic ApoE4 on neuronal AB production. Secretory factors in conditioned media from ApoE4 astrocytes significantly increased amyloid precursor protein (APP) levels and AB secretion in neurons. We further found that increased cholesterol secretion from ApoE4 astrocytes was necessary and sufficient to induce the formation of lipid rafts that potentially provide a physical platform for APP localization and facilitate its processing. Our study reveals the contribution of ApoE4 astrocytes to amyloidosis in neurons by expanding lipid rafts and facilitating AB production through an oversupply of cholesterol.

2021-08-31T15:00:00Z Moon, Dae Won Park, Young Ho Lee, Sun Young Lim, Heejin Kwak, SuHwa Kim, Minseok S. Kim, Hyunmin Kim, Eunjoo Jung, Yebin Hoe, Hyang-Sook Kim, Sungjee Lim, Dong-Kwon Kim, Chul-Hoon In, Su-Il https://scholar.dgist.ac.kr/handle/20.500.11750/11783 2025-07-24T07:33:40Z 2020-03-31T15:00:00Z

Title: Multiplex Protein Imaging with Secondary Ion Mass Spectrometry Using Metal Oxide Nanoparticle-Conjugated Antibodies Author(s): Moon, Dae Won; Park, Young Ho; Lee, Sun Young; Lim, Heejin; Kwak, SuHwa; Kim, Minseok S.; Kim, Hyunmin; Kim, Eunjoo; Jung, Yebin; Hoe, Hyang-Sook; Kim, Sungjee; Lim, Dong-Kwon; Kim, Chul-Hoon; In, Su-Il Abstract: In spite of recent developments in mass spectrometry imaging techniques, high-resolution multiplex protein bioimaging techniques are required to unveil the complex inter- and intracellular biomolecular interactions for accurate understanding of life phenomena and disease mechanisms. Herein, we report multiplex protein imaging with secondary ion mass spectrometry (SIMS) using metal oxide nanoparticle (MONP)-conjugated antibodies with <300 nm spatial resolution in the low ion dose without ion beam damage because of the high secondary ion yields of the MONPs, which can provide simultaneous imaging of several proteins, especially from cell membranes. We applied our new imaging technique for the study of hippocampal tissue samples from control and Alzheimer's disease (AD) model mice; the proximity of protein clusters in the hippocampus CA1 region showed intriguing dependence on aging and AD progress, suggesting that protein cluster proximity may be helpful for understanding pathological pathways in the microscopic cellular level. © 2020 American Chemical Society.

2020-03-31T15:00:00Z Kim, Jae Young Lim, Heejin Lee, Sun Young Song, Cheol Park, Ji-Won Shin, Hyeon Ho Lim, Dong-Kwon Moon, Dae Won https://scholar.dgist.ac.kr/handle/20.500.11750/10486 2025-07-25T03:36:12Z 2019-06-30T15:00:00Z

Title: Graphene-Coated Glass Substrate for Continuous Wave Laser Desorption and Atmospheric Pressure Mass Spectrometric Imaging of a Live Hippocampal Tissue Author(s): Kim, Jae Young; Lim, Heejin; Lee, Sun Young; Song, Cheol; Park, Ji-Won; Shin, Hyeon Ho; Lim, Dong-Kwon; Moon, Dae Won Abstract: The atmospheric pressure mass spectrometric (AP-MS) imaging technology combined with an inverted optical microscopic system is a powerful tool for determining the presence and spatial distributions of specific biomolecules of interest in live tissues. Efficient desorption and ionization are essential to acquire mass spectrometric (MS) information in an ambient environment. In this study, we demonstrate a new and efficient desorption process using a graphene-coated glass substrate and a continuous wave (CW) laser for high-resolution AP-MS imaging of a live hippocampal tissue. We found that desorption of biomolecules in a live tissue slice was possible with the aid of a graphene-coated glass substrate and indirect application of a 532 nm CW laser on the graphene substrate. Interestingly, the desorption efficiency of a live tissue on the graphene-coated substrate was strongly dependent on the number of graphene layers. Single-layer graphene was found to be the most sensitive substrate for efficient desorption and reproducible high-resolution hippocampal tissue imaging applications. The subsequent ionization process using nonthermal plasma generated sufficient amounts of molecular ions to obtain high-resolution two-dimensional MS images of the cornu ammonis and the dentate gyrus regions of the hippocampus. Therefore, graphene-coated substrates could be a promising platform to induce an efficient desorption process essential for highly reproducible ambient MS imaging. Copyright © 2019 American Chemical Society.

2019-06-30T15:00:00Z Park, Jimin Yang, Ki Dong Kim, Na-Young Jung, Kang-Won Le, Viet-Duc Lim, Hee-Jin An, Junghyun Jin, Kyoungsuk Kim, Yong-Hyun Nam, Ki Tae Moon, Daewon https://scholar.dgist.ac.kr/handle/20.500.11750/9342 2025-07-25T02:38:21Z 2018-08-31T15:00:00Z

Title: Quantitative Analysis of Calcium Phosphate Nanocluster Growth Using Time-of-Flight Medium-Energy-Ion-Scattering Spectroscopy Author(s): Park, Jimin; Yang, Ki Dong; Kim, Na-Young; Jung, Kang-Won; Le, Viet-Duc; Lim, Hee-Jin; An, Junghyun; Jin, Kyoungsuk; Kim, Yong-Hyun; Nam, Ki Tae; Moon, Daewon Abstract: One of the remaining challenges in material chemistry is to unveil the quantitative compositional/structural information and thermodynamic nature of inorganic materials especially in the initial nucleation and growth step. In this report, we adopted newly developed time-of-flight medium-energy-ion-scattering (TOF-MEIS) spectroscopy to address this challenge and explored heterogeneously grown nanometer-sized calcium phosphate as a model system. With TOF-MEIS, we discovered the existence of calcium-rich nanoclusters (Ca/P ∼ 3) in the presence of the non-collagenous-protein-mimicking passivating ligands. Over the reaction, these clusters progressively changed their compositional ratio toward that of a bulk phase (Ca/P ∼ 1.67) with a concurrent increase in their size to ∼2 nm. First-principles studies suggested that the calcium-rich nanoclusters can be stabilized through specific interactions between the ligands and clusters, emphasizing the important role of template on guiding the chemical and thermodynamic nature of inorganic materials at the nanoscale. © 2018 American Chemical Society.

2018-08-31T15:00:00Z