Publications by authors named "Seung Hyeok Seok"

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  • The study investigates mass mortality in Golden Trevally at an aquarium, identifying gas bubble disease (GBD) as the cause and aiming to prevent future incidents.
  • The researchers examined fish showing GBD symptoms and conducted necropsies, finding gas bubbles in various tissues.
  • Results indicated that structural defects in the water system led to high total dissolved gas levels, emphasizing the need for monitoring and maintaining water quality to protect aquatic species.
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  • Diabetic retinopathy (DR) is a serious complication of diabetes that can lead to vision loss and blindness, with current treatments often being invasive and having side effects.
  • This study explores the use of a histamine H receptor (HRH4) antagonist as a potential preventive therapy for DR in a mouse model, highlighting its effects on inflammation and retinal vascular leakage.
  • Results show that the HRH4 antagonist effectively reduces macrophage infiltration and retinal damage without causing toxicity, suggesting that targeting HRH4 could be a new strategy for preventing and treating DR.
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Calcineurin inhibitors (CNIs) are essential in liver transplantation (LT); however, their long-term use leads to various adverse effects. The anti-intercellular adhesion molecule (ICAM)-1 monoclonal antibody MD3 is a potential alternative to CNI. Despite its promising results with short-term therapy, overcoming the challenge of chronic rejection remains important.

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  • Spinal deformities like kyphoscoliosis are frequently observed in cetaceans, particularly bottlenose dolphins, but information on their occurrence in narrow-ridged finless porpoises (NFP) is scarce.
  • In November 2021, two dead NFPs were found in South Korea, and post-mortem computed tomography (PMCT) revealed they had congenital and degenerative forms of kyphoscoliosis.
  • The study suggests that while kyphoscoliosis may not have directly caused their deaths, it likely limited their spinal movement and mobility, which could have contributed to their demise, marking a significant documentation in understanding NFP health.
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  • Researchers developed uniform-sized clodronate-encapsulated liposome nanoplatforms to enhance macrophage depletion for immunotherapy, addressing limitations of previous formulations.
  • The new liposomes were functionalized for targeted delivery and labeled for in vivo imaging, demonstrating stability and effective biodistribution in tests.
  • Among the four types created, the mannosylated liposome showed superior ability to deplete M2 macrophages in both normal liver and tumor settings, indicating its potential as an effective treatment option.
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  • Zebrafish have become a popular research model since the 1980s, but current ethical guidelines for their treatment, especially concerning euthanasia, are insufficient.
  • A study in South Korea assessed local zebrafish research practices and highlighted the use of hypothermic shock as a common method for humane euthanasia.
  • Researchers advocated for national guidelines to improve zebrafish welfare and established best practices, aiming to raise awareness and address welfare concerns in the field.
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  • Recent research is focusing on tumor-associated macrophages (TAMs) to change the tumor microenvironment (TME) and boost anti-tumor effects.
  • The study used single-cell RNA sequencing to explore how TAMs affect the TME during the early stages of tumor growth, finding that removing TAMs alters cancer cell behavior and activates CD8 T cells.
  • The research identified Galectin-1 (Gal-1) as a key factor in this process, where inhibiting Gal-1 can enhance immune responses and reduce tumor growth, indicating potential targets for cancer therapy.
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Macrophages are essential innate immune cells found throughout the body that have protective and pathogenic functions in many diseases. When activated, macrophages can mediate the phagocytosis of dangerous cells or materials and participate in effective tissue regeneration by providing growth factors and anti-inflammatory molecules. Ex vivo-generated macrophages have thus been used in clinical trials as cell-based therapies, and based on their intrinsic characteristics, they outperformed stem cells within specific target diseases.

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  • The study investigates the effects of empagliflozin (EMPA) and sotagliflozin (SOTA) on heart failure and diabetes using a zebrafish model, revealing both drugs improve survival and cardiac function but differ in effectiveness at higher concentrations.
  • EMPA and SOTA were found to similarly inhibit sodium-hydrogen exchanger 1 (NHE1), suggesting this mechanism contributes to their cardioprotective effects.
  • However, at 25 μM concentration, SOTA resulted in poorer outcomes compared to EMPA, indicating that while both drugs have beneficial effects, EMPA may be the safer choice at higher doses.
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  • There is a significant connection between cellular metabolism and the immune response of macrophages, particularly in the context of Mycobacteroides massiliense infections.
  • The intracellular replication of this bacterium relies on the activity of pyruvate dehydrogenase kinase (PDK), prompting macrophages to shift their metabolic processes toward increased glycolysis and decreased oxidative phosphorylation upon infection.
  • Treatment with dichloroacetate (DCA), a PDK inhibitor, can reverse this metabolic shift, activate autophagy, and limit bacterial growth within macrophages, highlighting it as a potential therapeutic approach for managing severe M. massiliense infections.
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  • Immune checkpoint inhibitors like anti-PD1 help fight tumors by activating the immune system, but measuring their success just by tumor size may not be reliable.
  • Researchers used mannosylated-serum albumin (MSA) nanoparticles labeled with a radioactive isotope to noninvasively assess the immune environment in tumors, specifically by targeting macrophages associated with anti-PD1 therapy.
  • Results showed that mice responsive to anti-PD1 had more tumor-associated macrophages (TAMs) early in treatment, suggesting that imaging TAMs can effectively indicate the immune response to treatment with immune checkpoint inhibitors.
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  • * The model was established by using D-glucose and streptozotocin to induce DM-like symptoms, followed by treatment with terfenadine to cause heart failure in the zebrafish.
  • * Results showed that the diabetic zebrafish had abnormal glucose levels and heart contractions, making it a valuable tool for both drug testing and studying the underlying mechanisms of diabetes-related heart issues.
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Immunotoxicity has been an important topic in toxicology since inadvertent exposures to xenobiotics were found to alter immune functions in humans. While rodent toxicity tests can reveal some levels of immunotoxicity, alternative methods must be developed to identify the detailed mechanisms. In this study, a method of in vitro prediction of innate immune suppression by substances was developed using a genomics approach.

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  • * The researchers modified a clickable albumin nanoplatform (CAN) by attaching mannose molecules, enhancing its imaging capabilities and pharmacokinetics for better visualization of lung lesions.
  • * Imaging techniques like SPECT/CT and PET demonstrated that the modified albumin (MSA) could effectively identify metastatic lesions in the lung, showing a strong link between its signal and the extent of metastases.
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  • Immune checkpoint inhibitors and VEGFR tyrosine kinase inhibitors (TKIs) are common treatments for renal cell carcinoma (RCC), but a new strategy targeting CD47 could enhance anti-tumor effects.* -
  • CD47 sends a "don't eat me" signal to macrophages, which are immune cells that can attack tumors; high levels of CD47 in RCC are linked to poorer survival rates.* -
  • Blocking CD47 with antibodies boosts the ability of macrophages to attack RCC cells, especially when combined with VEGFR TKIs, suggesting a promising new treatment approach for RCC patients.*
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Re-emerging viral threats have continued to challenge the medical and public health systems. It has become clear that a significant number of severe viral infection cases are due to an overreaction of the immune system, which leads to hyperinflammation. In this study, we aimed to demonstrate the therapeutic efficacy of the dexamethasone nanomedicine in controlling the symptoms of influenza virus infection.

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  • Metabolic dysregulation plays a key role in cancer, and Nicotinamide (NAM), a form of vitamin B3, is explored for its potential therapeutic effects in triple-negative breast cancer (TNBC).
  • The study found that NAM alters mitochondrial function by decreasing membrane potential and ATP production while enhancing certain metabolic pathways, ultimately increasing reactive oxygen species (ROS).
  • Elevated ROS levels lead to cancer cell apoptosis and hinder tumor growth and metastasis, suggesting that NAM could be repurposed as a promising anti-metabolic agent for treating TNBC.
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Matrix stiffness, a critical physical property of the cellular environment, is implicated in epidermal homeostasis. In particular, matrix stiffening during the pathological progression of skin diseases appears to contribute to cellular responses of keratinocytes. However, it has not yet elucidated the molecular mechanism underlying matrix-stiffness-mediated signaling in coordination with chemical stimuli during inflammation and its effect on proinflammatory cytokine production.

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Introduction: Typhoid incidence in children is higher in urban areas than in rural areas of Bangladesh. This study examined whether healthy urban children harboured higher levels of Salmonella genes than healthy rural children.

Methodology: Stool samples from 140 children were studied: 70 from rural areas and 70 from urban metropolitan areas.

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Objective: Dysfunctional resolution of intestinal inflammation and altered mucosal healing are essential features in the pathogenesis of inflammatory bowel disease (IBD). Intestinal macrophages are vital in the process of inflammation resolution, but the mechanisms underlying their mucosal healing capacity remain elusive.

Design: We investigated the role of the prostaglandin E (PGE) receptor PTGER4 on the differentiation of intestinal macrophages in patients with IBD and mouse models of intestinal inflammation.

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Introduction: Systemic histaminergic activity is elevated in patients with diabetes mellitus. There are a few studies suggesting that histamine is implicated in the pathogenesis of diabetes, but the exact role of histamine in the development of diabetic retinopathy is unclear. The aim of this study was to investigate the role of histamine receptor H4 (HRH4) in the regulation of retinal pigment epithelium (RPE)-derived pro-angiogenic and anti-angiogenic factors under diabetic conditions.

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  • Human cytomegalovirus (HCMV) uses the interleukin-10 (IL-10) pathway to weaken the host's immune response, making it easier for other infections to occur alongside HCMV.
  • Research demonstrated that HCMV infection increases IL-10 production in macrophages, which in turn aids the growth of non-tuberculous mycobacteria (NTM).
  • Transcriptomic analysis indicated that HCMV infection suppresses key immune regulatory pathways, hindering the body's response to co-infection with NTM by lowering levels of interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), and interleukin-1 (IL-1).
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As current therapies benefit only a minority of cancer patients, additional therapeutic targets are needed. Tumor-associated macrophages (TAMs) have attracted attention for improving therapeutic responses, yet regulatory strategies remain elusive. Here, we show that the protein kinase A catalytic subunit (PKA-C) acts as a molecular switch, inducing a pro-tumoral immunosuppressive macrophage phenotype within tumors.

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Overwhelming and persistent inflammation of retinal pigment epithelium (RPE) induces destructive changes in the retinal environment. However, the precise mechanisms remain unclear. In this study, we aimed to investigate RPE-specific biological and metabolic responses against intense inflammation and identify the molecular characteristics determining pathological progression.

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