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57 result(s) for "Koh, Jun-Young"
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Wrist-wearable bioelectrical impedance analyzer with miniature electrodes for daily obesity management
Bioelectrical impedance analysis (BIA) is used to analyze human body composition by applying a small alternating current through the body and measuring the impedance. The smaller the electrode of a BIA device, the larger the impedance measurement error due to the contact resistance between the electrode and human skin. Therefore, most commercial BIA devices utilize electrodes that are large enough (i.e., 4 × 1400 mm 2 ) to counteract the contact resistance effect. We propose a novel method of compensating for contact resistance by performing 4-point and 2-point measurements alternately such that body impedance can be accurately estimated even with considerably smaller electrodes (outer electrodes: 68 mm 2 ; inner electrodes: 128 mm 2 ). Additionally, we report the use of a wrist-wearable BIA device with single-finger contact measurement and clinical test results from 203 participants at Seoul St. Mary’s Hospital. The correlation coefficient and standard error of estimate of percentage body fat were 0.899 and 3.76%, respectively, in comparison with dual-energy X-ray absorptiometry. This result exceeds the performance level of the commercial upper-body portable body fat analyzer (Omron HBF-306). With a measurement time of 7 s, this sensor technology is expected to provide a new possibility of a wearable bioelectrical impedance analyzer, toward obesity management.
Unraveling the role of the mitochondrial one-carbon pathway in undifferentiated thyroid cancer by multi-omics analyses
The role of the serine/glycine metabolic pathway (SGP) has recently been demonstrated in tumors; however, the pathological relevance of the SGP in thyroid cancer remains unexplored. Here, we perform metabolomic profiling of 17 tumor-normal pairs; bulk transcriptomics of 263 normal thyroid, 348 papillary, and 21 undifferentiated thyroid cancer samples; and single-cell transcriptomes from 15 cases, showing the impact of mitochondrial one-carbon metabolism in thyroid tumors. High expression of serine hydroxymethyltransferase-2 (SHMT2) and methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) is associated with low thyroid differentiation scores and poor clinical features. A subpopulation of tumor cells with high mitochondrial one-carbon pathway activity is observed in the single-cell dataset. SHMT2 inhibition significantly compromises mitochondrial respiration and decreases cell proliferation and tumor size in vitro and in vivo. Collectively, our results highlight the importance of the mitochondrial one-carbon pathway in undifferentiated thyroid cancer and suggest that SHMT2 is a potent therapeutic target. Different types of metabolic rewiring are reported to drive cancer development and as a potential therapeutic target. Here, the authors perform multi-omics analyses in a cohort of human normal and malignant thyroid samples and show association of mitochondrial one-carbon metabolism with undifferentiated thyroid cancer.
Moxibustion-Simulating Bipolar Radiofrequency Suppresses Weight Gain and Induces Adipose Tissue Browning via Activation of UCP1 and FGF21 in a Mouse Model of Diet-Induced Obesity
Background. Obesity is a pathological condition associated with various diseases including diabetes, stroke, arthritis, infertility, and heart disease. Moxibustion is widely used to prevent and manage obesity in traditional Asian medicine. We tested our hypothesis that moxibustion-simulating bipolar radiofrequency (M-RF) can suppress total body and white adipose tissue (WAT) weight gain via induction of WAT browning in a mouse model of diet-induced obesity (DIO). Methods. We designed an M-RF device that could accurately adjust the depth and temperature at which heat stimulation was administered into the abdomen of DIO mice. High-fat-fed male C57BL/6 mice were treated with the M-RF device every two or three days for three weeks. We then harvested WAT and serum from the mice and measured total body and WAT weight, size of adipocytes, mitochondrial contents, features of the dead adipocyte environment, and levels of uncoupling protein 1 (UCP1) and fibroblast growth factor 21 (FGF21). Results. Heat stimulation by M-RF in DIO mice resulted in precise temperature adjustment in the mice abdomen, with variance less than 1°C. Additionally, M-RF stimulation inhibited body and WAT weight gain, resulting in increased formation of beige adipocytes, increased mitochondrial content, and decreased formation of dead adipocytes in WAT. Moreover, treatment of M-RF induced expression of UCP1 and FGF21 in serum and/or epididymal WATs in DIO mice. Conclusion. Heat stimulation by M-RF treatment induced upregulation of UCP1 and FGF21 expression in serum and/or WATs, which was correlated with reduced total body and WAT weight gain in DIO mice.
Effects of Ginsenoside Rg3 on Inhibiting Differentiation, Adipogenesis, and ER Stress-Mediated Cell Death in Brown Adipocytes
Objectives. Ginsenoside Rg3 (Rg3), a main active component of Panax ginseng, has various therapeutic properties in literatures, and it has been studied for its potential use in obesity control due to its antiadipogenic effects in white adipocytes. However, little is known about its effects on brown adipocytes. Methods. The mechanisms through which Rg3 inhibits differentiation, adipogenesis, and ER stress-mediated cell death in mouse primary brown adipocytes (MPBAs) are explored. Results. Rg3 significantly induced cytotoxicity in differentiated MPBAs but not in undifferentiated MPBAs. Rg3 treatment downregulated the expression of differentiation and adipogenesis markers and the level of perilipin in MPBAs while upregulating the expression of lipolytic Kruppel-like factor genes. Rg3 also induced lipolysis and efflux of triglycerides from MPBAs and subsequently increased proinflammatory cytokine levels. Notably, Rg3 treatment resulted in elevation of ER stress and proapoptotic markers in MPBAs. Conclusions. Our results demonstrate that Rg3 is able to selectively exert cytotoxicity in differentiated MPBAs while leaving undifferentiated MPBAs intact, resulting in the induction of ER stress and subsequent cell death in MPBAs via regulation of various genes related to adipocyte differentiation, adipogenesis, lipolysis, and inflammation. These results indicate that further studies on the potential therapeutic applications of Rg3 are warranted.
Novel anti-CD73-IL-2v bispecific fusion protein augments antitumor immunity by alleviating immunosuppressive adenosine pathways in CD8+ T cells
BackgroundAdenosine accumulated in the tumor microenvironment functions as an immune-modulating factor, exerting immunosuppressive actions via adenosine A2A/A2B receptor (A2AR/A2BR) in various immune cell types. CD73, a key enzymatic regulator responsible for adenosine production, is frequently overexpressed in diverse cancers, and its overexpression is associated with reduced responsiveness to conventional anti-cancer drug treatments such as chemotherapy, radiation therapy, targeted therapy, or immunotherapy. Despite numerous therapeutic applications of IL-2 in cancer immunotherapy, the relationship between the CD73-adenosine axis and IL-2-based immunotherapy remains largely unexplored.MethodsTo evaluate the effect of CD73 blockade on IL-2 signaling of CD8+ T cells, we screened novel CD73 antibodies using human single-chain variable fragment phage library and immunized Alpaca phage library. To optimize targeting to CD73-expressing cells and reinvigorate the antitumor effect of IL-2 in adenosine-rich microenvironment, we engineered a novel bifunctional GI-αCD73/IL-2v fusion protein. Functionality of GI-αCD73/IL-2v fusion protein was assessed in the in vitro cell-based assays and the in vivo tumor-bearing mouse model or cynomolgus monkey.ResultsIL-2-induced increase in proliferation of CD8+ T cells was not observed under adenosine-rich microenvironment. We demonstrated that the functional impairment of IL-2 signaling in CD8+ T cells in these conditions can be reversed by our anti-CD73 antibody (GI-αCD73). Furthermore, GI-αCD73/IL-2v fusion protein significantly restored the impaired proliferation of CD8+ T cells and consequently enhanced tumor cell killing under adenosine-mediated immunosuppression, surpassing the combined treatment of GI-αCD73 and Fc-IL-2v. These synergistic effects were attributed to the enhanced delivery of the IL-2v component of GI-αCD73/IL-2v to IL-2Rβγ on CD73-expressing CD8+ T cells through a cis-binding mechanism. GI-αCD73/IL-2v elicited a potent antitumor effect in both the human CD73 knock-in (hCD73 KI) mouse model and the humanized mouse model. In non-human primates, GI-αCD73/IL-2v exhibited excellent tolerability while inducing robust and durable expansions of cytotoxic lymphocytes.ConclusionsGI-αCD73/IL-2v bispecific protein is a novel and potent immunocytokine with significant antitumor immunity through cis-binding on CD8+ T cells.
Anti-Angiogenic Property of Free Human Oligosaccharides
Angiogenesis, a fundamental process in human physiology and pathology, has attracted considerable attention owing to its potential as a therapeutic strategy. Vascular endothelial growth factor (VEGF) and its receptor (VEGFR) are deemed major mediators of angiogenesis. To date, inhibition of the VEGF-A/VEGFR-2 axis has been an effective strategy employed in the development of anticancer drugs. However, some limitations, such as low efficacy and side effects, need to be addressed. Several drug candidates have been discovered, including small molecule compounds, recombinant proteins, and oligosaccharides. In this review, we focus on human oligosaccharides as modulators of angiogenesis. In particular, sialylated human milk oligosaccharides (HMOs) play a significant role in the inhibition of VEGFR-2-mediated angiogenesis. We discuss the structural features concerning the interaction between sialylated HMOs and VEGFR-2 as a molecular mechanism of anti-angiogenesis modulation and its effectiveness in vivo experiments. In the current state, extensive clinical trials are required to develop a novel VEGFR-2 inhibitor from sialylated HMOs.
6′-Sialylgalactose inhibits vascular endothelial growth factor receptor 2-mediated angiogenesis
Angiogenesis should be precisely regulated because disordered neovascularization is involved in the aggravation of multiple diseases. The vascular endothelial growth factor (VEGF)-A/VEGF receptor 2 (VEGFR-2) axis is crucial for controlling angiogenic responses in vascular endothelial cells (ECs). Therefore, inactivating VEGFR-2 signaling may effectively suppress aberrant angiogenesis and alleviate related symptoms. In this study, we performed virtual screening, identified the synthetic disaccharide 6′-sialylgalactose (6SG) as a potent VEGFR-2-binding compound and verified its high binding affinity by Biacore assay. 6SG effectively suppressed VEGF-A-induced VEGFR-2 phosphorylation and subsequent in vitro angiogenesis in HUVECs without inducing cytotoxicity. 6SG also inhibited VEGF-A-induced extracellular-regulated kinase (ERK)/Akt activation and actin stress fiber formation in HUVECs. We demonstrated that 6SG inhibited retinal angiogenesis in a mouse model of retinopathy of prematurity and tumor angiogenesis in a xenograft mouse model. Our results suggest a potential therapeutic benefit of 6SG in inhibiting angiogenesis in proangiogenic diseases, such as retinopathy and cancer. Abnormal blood vessel formation: Synthetic disaccharide shows therapeutic promise Therapy based on a synthetic molecule can block abnormal blood vessel formation, limiting the progression of diabetic eye conditions and tumor growth in mice. The growth of new blood vessels from existing vessels, called angiogenesis, is critical to wound healing and embryonic development. The main angiogenesis signalling pathway involves growth factors, including one called VEGFR-2. Disruption to this pathway plays a significant part in the development of multiple diseases. A South Korean team led by Ki-Tae Ha at Pusan National University, Yangsan, and Young Jun Koh at Dongguk University, Seoul, identified and trialed a synthetic disaccharide capable of binding to and limiting the activity of VEGFR-2 during faulty signaling. Trials on mice with the diabetic eye condition retinopathy, and mice with implanted tumors, showed that the compound inhibited excessive angiogenesis and limited disease progression.
Bone marrow–derived circulating progenitor cells fail to transdifferentiate into adipocytes in adult adipose tissues in mice
Little is known about whether bone marrow-derived circulating progenitor cells (BMDCPCs) can transdifferentiate into adipocytes in adipose tissues or play a role in expanding adipocyte number during adipose tissue growth. Using a mouse bone marrow transplantation model, we addressed whether BMDCPCs can transdifferentiate into adipocytes under standard conditions as well as in the settings of diet-induced obesity, rosiglitazone treatment, and exposure to G-CSF. We also addressed the possibility of transdifferentiation to adipocytes in a murine parabiosis model. In each of these settings, our findings indicated that BMDCPCs did not transdifferentiate into either unilocular or multilocular adipocytes in adipose tissues. Most BMDCPCs became resident and phagocytic macrophages in adipose tissues--which resembled transdifferentiated multilocular adipocytes by appearance, but displayed cell surface markers characteristic for macrophages - in the absence of adipocyte marker expression. When exposed to adipogenic medium in vitro, bone marrow cells differentiated into multilocular, but not unilocular, adipocytes, but transdifferentiation was not observed in vivo, even in the contexts of adipose tissue regrowth or dermal wound healing. Our results suggest that BMDCPCs do not transdifferentiate into adipocytes in vivo and play little, if any, role in expanding the number of adipocytes during the growth of adipose tissues.
Anti-Neuroinflammatory Effects and Mechanism of Action of Fructus ligustri lucidi Extract in BV2 Microglia
For centuries, Fructus ligustri lucidi (FLL; the fruit of Ligustrum lucidum Aiton or Ligustrum japonicum Thunb.) has been commonly used in traditional Chinese medicine for treating hepatitis and aging-related symptoms and in traditional Korean medicine to detoxify kidneys and the liver. Pharmacological research has shown FLL has antioxidant, anti-inflammatory, anticancer, anti-osteoporosis, and hepatoprotective activities. This study was undertaken to investigate the effects of FLL extract (FLLE) on neuroinflammation. After setting a non-toxic concentration using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide] assay data, we investigated the effects of FLLE using Western blotting, cell migration, enzyme-linked immunosorbent assay, a nitric oxide (NO) assay, and immunofluorescence staining in lipopolysaccharide (LPS)-stimulated murine BV2 microglial cells. FLLE was non-toxic to BV2 cells up to a concentration of 500 μg/mL and concentration-dependently inhibited the production of NO and prostaglandin E2 and the protein levels of inducible nitric oxide synthase and cyclooxygenase-2 under LPS-induced inflammatory conditions. It also inhibited the secretion of the inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Furthermore, FLLE pretreatment attenuated LPS-induced increases of CD68 (a marker of microglia activation) and suppressed the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) signaling pathways in LPS-stimulated BV2 cells, and significantly increased heme oxygenase (HO)-1 levels. FLLE also reduced the LPS-induced increase in the migratory ability of BV2 cells and the phosphorylation of vascular endothelial growth factor receptor 1. Collectively, FLLE effectively inhibited inflammatory response by suppressing the MAPK and NF-κB signaling pathways and inducing HO-1 in LPS-stimulated BV2 microglial cells. Our findings provide a scientific basis for further study of FLL as a candidate for preventing or alleviating neuroinflammation.
1072 GI-108, a novel bispecific fusion protein augments anti-tumor immunity by alleviating immunosuppressive adenosine pathway in CD8+ T cells
BackgroundCD73, a pivotal ectoenzyme responsible for the conversion of adenosine monophosphate (AMP) to adenosine, exhibits widespread expression on tumor cells and promotes accumulation of adenosine within the tumor microenvironment (TME). Adenosine acts as a potent immunomodulatory factor, effectively attenuating anti-tumor immune responses in the TME by binding to adenosine receptors expressed on diverse immune cell populations. Consequently, the elevated levels of adenosine pose significant barriers to the efficacy of various anti-cancer therapies, including chemotherapy, targeted therapy, and immunotherapy. Despite the considerable potential of interleukin-2 (IL-2) as an immunocytokine for stimulating cytotoxic lymphocytes, IL-2 demonstrates limited efficacy in overcoming immunosuppression induced by high levels of adenosine.MethodsWe generated GI-108, a novel bifunctional fusion protein. The anti-CD73 antibody was selected from clones screened in the single-chain variable fragment (scFv) phage library based on its CD73 blocking efficacy. The IL-2 variant which lacks binding affinity to the IL-2Rα to minimize selectivity to regulatory T cells, was then fused to the anti-CD73 antibody.ResultsGI-108 showed comparable binding affinity to human CD73 (hCD73) as Oleclumab, despite targeting different binding epitopes. Compared to Oleclumab, GI-108 demonstrated superior maximum efficacy in blocking both membrane-bound and soluble CD73 without inducing any hook effects. By attenuating its affinity to IL-2Rα, GI-108 selectively increased CD8+ T cells while minimizing its impact on regulatory T cells. In non-human primates, the administration of GI-108 led to a significant increase in cytotoxic lymphocytes. Similarly, a greater activation of the IL-2-STAT5 signaling axis by GI-108 was observed in CD8+ T cells than regulatory T cells. Importantly, the phosphorylation of STAT5 in CD8+ T cells by GI-108 was greater than that by wild-type IL-2, Proleukin. This observation was attributed to the binding of GI-108 to CD73-high CD8+ T cells in cis-binding manner, facilitating the transmission of a stronger signal to IL-2Rβγ. GI-108 effectively restored the proliferation or activity of CD8+ T cells in the presence of high levels of AMP. The reinvigorated cytolytic CD8+ T cells demonstrated sufficient cytotoxicity against CD73high tumor cells (MDA-MB-231). Administration of GI-108 to a humanized mouse bearing MDA-MB-231 induced significant inhibition of tumor growth.ConclusionsGI-108 is a potent bifunctional fusion protein with the ability to selectively target to the tumor site to reinvigorate immunosuppressed immune cells in the TME. As such, this innovative IL-2-based bifunctional agent provides a promising therapeutic strategy for the treatment of cancer.