Konkuk University

About: Konkuk University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Apoptosis. The organization has 13405 authors who have published 27027 publications receiving 506313 citations.

Double-$\Lambda$ hypernuclei observed in a hybrid emulsion experiment

Abstract: A hybrid experiment with nuclear emulsion and scintillating-fiber detectors (KEK-E373) has been performed to search for double-strangeness systems. Among about 10${}^{3}$ events of ${\ensuremath{\Xi}}^{\ensuremath{-}}$ hyperons captured at rest by emulsion nuclei, we have observed four events which clearly show the topology of cascade weak decays of double-$\ensuremath{\Lambda}$ hypernuclei including the ``Nagara'' event. Regarding the Nagara event, values of the two-$\ensuremath{\Lambda}$ binding energy (${B}_{\ensuremath{\Lambda}\ensuremath{\Lambda}}$) and the $\ensuremath{\Lambda}$-$\ensuremath{\Lambda}$ interaction energy ($\ensuremath{\Delta}{B}_{\ensuremath{\Lambda}\ensuremath{\Lambda}}$) of ${}_{\ensuremath{\Lambda}}^{}{}_{\ensuremath{\Lambda}}^{6}\mathrm{He}$ have been revised to 6.91 $\ifmmode\pm\else\textpm\fi{}$ 0.16 and 0.67 $\ifmmode\pm\else\textpm\fi{}$ 0.17 MeV, respectively, due to the recent change of the ${\ensuremath{\Xi}}^{\ensuremath{-}}$ mass value (Particle Data Group). For another three events, we have determined possible species of double-$\ensuremath{\Lambda}$ hypernuclei together with their binding energies.

Efficient scalable production of therapeutic microvesicles derived from human mesenchymal stem cells.

Abstract: Microvesicles (MVs) released by cells are involved in a multitude of physiological events as important mediators of intercellular communication. MVs derived from mesenchymal stem cells (MSCs) contain various paracrine factors from the cells that primarily contribute to their therapeutic efficacy observed in numerous clinical trials. As nano-sized and bi-lipid layered vesicles retaining therapeutic potency equivalent to that of MSCs, MSC-derived MVs have been in focus as ideal medicinal candidates for regenerative medicine, and are preferred over MSC infusion therapy with their improved safety profiles. However, technical challenges in obtaining sufficient amounts of MVs have limited further progress in studies and clinical application. Of the multiple efforts to reinforce the therapeutic capacity of MSCs, few studies have reportedly examined the scale-up of MSC-derived MV production. In this study, we successfully amplified MV secretion from MSCs compared to the conventional culture method using a simple and efficient 3D-bioprocessing method. The MSC-derived MVs produced in our dynamic 3D-culture contained numerous therapeutic factors such as cytokines and micro-RNAs, and showed their therapeutic potency in in vitro efficacy evaluation. Our results may facilitate diverse applications of MSC-derived MVs from the bench to the bedside, which requires the large-scale production of MVs.

The antipsychotic agent chlorpromazine induces autophagic cell death by inhibiting the Akt/mTOR pathway in human U-87MG glioma cells.

Abstract: 2-Chloro-10-[3(-dimethylamino)propyl]phenothiazine mono hydrochloride (chlorpromazine; CPZ) is an antipsychotic agent that was originally developed to control psychotic disorders. The cytotoxic properties of the CPZ are well known, but its mechanism of action is poorly understood. In this study, we investigated the role of apoptosis and autophagy in CPZ-induced cytotoxicity in U-87MG glioma cells. CPZ treatment inhibited cell proliferation and long-term clonogenic survival. Additionally, CPZ triggered autophagy, as indicated by electron microscopy and accumulation of the membrane form of microtubule-associated protein 1 light chain 3 (LC3-II); however, CPZ did not induce apoptosis. Inhibition of autophagy by expression of Beclin 1 small interfering RNA (siRNA) in U-87MG cells attenuated CPZ-induced LC3-II formation. Furthermore, U-87MG cells expressing Beclin 1 siRNA attenuated CPZ-induced cell death. CPZ inhibited phosphatidylinositol 3-kinase (PI3K)/AKT/ mTOR pathway in U-87MG cells. Treatment with LY294002, a PI3K inhibitor, alone increased the accumulation of LC3-II and potentiated the effect of CPZ. In contrast, exogenous expression of AKT partially inhibited CPZ-induced LC3-II formation. When U-87MG cells were implanted into the brain of athymic nude mouse, CPZ triggered autophagy and inhibited xenograft tumor growth. These results provided the first evidence that CPZ-induced cytotoxicity is mediated through autophagic cell death in PTEN (phosphatase and tensin homolog deleted on chromosome 10)-null U-87MG glioma cells by inhibiting PI3K/AKT/mTOR pathway.

A Comprehensive Review on Factors Influences Biogenesis, Functions, Therapeutic and Clinical Implications of Exosomes

Abstract: Exosomes are nanoscale-sized membrane vesicles secreted by almost all cell types into the extracellular environment upon fusion of multivesicular bodies and plasma membrane. Biogenesis of exosomes is a protein quality control mechanism, and once released, exosomes transmit signals to other cells. The applications of exosomes have increased immensely in biomedical fields owing to their cell-specific cargos that facilitate intercellular communications with neighboring cells through the transfer of biologically active compounds. The diverse constituents of exosomes reflect their cell of origin and their detection in biological fluids represents a diagnostic marker for various diseases. Exosome research is expanding rapidly due to the potential for clinical application to therapeutics and diagnosis. However, several aspects of exosome biology remain elusive. To discover the use of exosomes in the biomedical applications, we must better understand the basic molecular mechanisms underlying their biogenesis and function. In this comprehensive review, we describe factors involved in exosomes biogenesis and the role of exosomes in intercellular signaling and cell-cell communications, immune responses, cellular homeostasis, autophagy, and infectious diseases. In addition, we discuss the role of exosomes as diagnostic markers, and their therapeutic and clinical implications. Furthermore, we addressed the challenges and outstanding developments in exosome research, and discuss future perspectives.