Publications by authors named "Sun-Kyoung Im"

Article Synopsis
  • * The study found that Nrf2, a protein that responds to ROS, is linked to suppressed anti-tumor responses in CTLs; Nrf2 knockout mice showed better tumor control when T cells were depleted.
  • * Nrf2-deficient CTLs displayed enhanced survival and function in the TME, suggesting that targeting Nrf2 could improve T-cell immunotherapy effectiveness against solid tumors.
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Background: Recombinant human interleukin (rhIL)-7-hyFc (efineptakin alfa; NT-I7) is a potent T-cell amplifier, with two IL-7 molecules fused to IgD/IgG4 elements. rhIL-7-hyFc promotes extensive infiltration of CD8 T cells into the tumor, concurrently increasing the numbers of intratumoral PD-1CD8 T cells. The hIL-2/TCB2 complex (SLC-3010) inhibits tumor growth by preferential activation of CD122 (IL-2Rβ) CD8 T cells and natural killer cells, over regulatory T cells (Tregs).

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Repeated pandemics caused by the influenza virus and severe acute respiratory syndrome coronavirus (SARS-CoV) have resulted in serious problems in global public health, emphasizing the need for broad-spectrum antiviral therapeutics against respiratory virus infections. Here, we show the protective effects of long-acting recombinant human interleukin-7 fused with hybrid Fc (rhIL-7-hyFc) against major respiratory viruses, including influenza virus, SARS-CoV-2, and respiratory syncytial virus. Administration of rhIL-7-hyFc in a therapeutic or prophylactic regimen induces substantial antiviral effects.

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Background: Comparisons of the gut microbiome of lean and obese humans have revealed that obesity is associated with the gut microbiome plus changes in numerous environmental factors, including high-fat diet (HFD). Here, we report that two species of Bifidobacterium are crucial to controlling metabolic parameters in the Korean population.

Results: Based on gut microbial analysis from 99 Korean individuals, we observed the abundance of Bifidobacterium longum and Bifidobacterium bifidum was markedly reduced in individuals with increased visceral adipose tissue (VAT), body mass index (BMI), blood triglyceride (TG), and fatty liver.

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Retinoic acid-related orphan receptor α (RORα) functions as a transcription factor for various biological processes, including circadian rhythm, cancer, and metabolism. Here, we generate intestinal epithelial cell (IEC)-specific RORα-deficient (RORα) mice and find that RORα is crucial for maintaining intestinal homeostasis by attenuating nuclear factor κB (NF-κB) transcriptional activity. RORα mice exhibit excessive intestinal inflammation and highly activated inflammatory responses in the dextran sulfate sodium (DSS) mouse colitis model.

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Katanin was the first microtubule (MT)-severing enzyme discovered, but how katanin executes MT severing remains poorly understood. Here, we report X-ray crystal structures of the apo and ATPγS-bound states of the catalytic AAA domain of human katanin p60 at 3.0 and 2.

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Genetically engineered mouse models are commonly preferred for studying the human disease due to genetic and pathophysiological similarities between mice and humans. In particular, Cre- system is widely used as an integral experimental tool for generating the conditional. This system has enabled researchers to investigate genes of interest in a tissue/cell (spatial control) and/or time (temporal control) specific manner.

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Schwann cells (SCs), the primary glia in the peripheral nervous system (PNS), display remarkable plasticity in that fully mature SCs undergo dedifferentiation and convert to repair SCs upon nerve injury. Dedifferentiated SCs provide essential support for PNS regeneration by producing signals that enhance the survival and axon regrowth of damaged neurons, but the identities of neurotrophic factors remain incompletely understood. Here we show that SCs express and secrete progranulin (PGRN), depending on the differentiation status of SCs.

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Although additional sex combs-like 1 (ASXL1) has been extensively described in hematologic malignancies, little is known about the molecular role of ASXL1 in organ development. Here, we show that Asxl1 ablation in mice results in postnatal lethality due to cyanosis, a respiratory failure. This lung defect is likely caused by higher proliferative potential and reduced expression of surfactant proteins, leading to reduced air space and defective lung maturation.

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Brain is a rich environment where neurons and glia interact with neighboring cells as well as extracellular matrix in three-dimensional (3D) space. Astrocytes, which are the most abundant cells in the mammalian brain, reside in 3D space and extend highly branched processes that form microdomains and contact synapses. It has been suggested that astrocytes cultured in 3D might be maintained in a less reactive state as compared to those growing in a traditional, two-dimensional (2D) monolayer culture.

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In native tissues, cellular and acellular components are anisotropically organized and often aligned in specific directions, providing structural and mechanical properties for actuating biological functions. Thus, engineering alignment not only allows for emulation of native tissue structures but might also enable implementation of specific functionalities. However, achieving desired alignment is challenging, especially in three-dimensional constructs.

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Several studies have demonstrated the therapeutic potential of applying microtubule- (MT-) stabilizing agents (MSAs) that cross the blood-brain barrier to promote axon regeneration and prevent axonal dystrophy in rodent models of spinal cord injury and neurodegenerative diseases. Paradoxically, administration of MSAs, which have been widely prescribed to treat malignancies, is well known to cause debilitating peripheral neuropathy and axon degeneration. Despite the growing interest of applying MSAs to treat the injured or degenerating central nervous system (CNS), consequences of MSA exposure to neurons in the central and peripheral nervous system (PNS) have not been thoroughly investigated.

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Tonicity-responsive enhancer (TonE) binding protein (TonEBP) is known as an osmosensitive transcription factor that regulates cellular homeostasis during states of hypo- and hypertonic stress. In addition to its role in osmoadaptation, growing lines of evidence suggest that TonEBP might have tonicity-independent functions. In particular, a number of studies suggest that inflammatory stimuli induce the expression and activation of TonEBP in peripheral immune cells.

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We present an engineered three-dimensional (3D) in vitro brain microvasculature system embedded within the bulk of a collagen matrix. To create a hydrogel template for the functional brain microvascular structure, we fabricated an array of microchannels made of collagen I using microneedles and a 3D printed frame. By culturing mouse brain endothelial cells (bEnd.

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Serotonin (5-HT) receptors of type 6 (5-HT6R) play important roles in mood, psychosis, and eating disorders. Recently, a growing number of studies support the use of 5-HT6R-targeting compounds as promising drug candidates for treating cognitive dysfunction associated with Alzheimer's disease. However, the mechanistic linkage between 5-HT6R and such functions remains poorly understood.

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During gastrulation, distinct lineage specification into three germ layers, the mesoderm, endoderm and ectoderm, occurs through an elaborate harmony between signaling molecules along the embryonic proximo-distal and anterior-posterior axes, and Nodal signaling plays a key role in the early embryonic development governing embryonic axis formation, mesoderm and endoderm specification, and left-right asymmetry determination. However, the mechanism by which Nodal expression is regulated is largely unknown. Here, we show that Meteorin regulates Nodal expression and is required for mesendoderm development.

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Sorting nexin 5 (Snx5) has been posited to regulate the degradation of epidermal growth factor receptor and the retrograde trafficking of cation-independent mannose 6-phosphate receptor/insulin-like growth factor II receptor. Snx5 has also been suggested to interact with Mind bomb-1, an E3 ubiquitin ligase that regulates the activation of Notch signaling. However, the in vivo functions of Snx5 are largely unknown.

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Mitochondria are key organelles dedicated to energy production. Crif1, which interacts with the large subunit of the mitochondrial ribosome, is indispensable for the mitochondrial translation and membrane insertion of respiratory subunits. To explore the physiological function of Crif1 in the heart, Crif1(f/f) mice were crossed with Myh6-cre/Esr1 transgenic mice, which harbor cardiomyocyte-specific Cre activity in a tamoxifen-dependent manner.

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Vaccinia-related kinase 1 (VRK1) is a crucial protein kinase for mitotic regulation. VRK1 is known to play a role in germ cell development, and its deficiency results in sterility. Here we describe that VRK1 is essential for the maintenance of spermatogonial stem cells.

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The heterogeneous cellular composition of the mammalian renal collecting duct enables regulation of fluid, electrolytes, and acid-base homeostasis, but the molecular mechanism of its development has yet to be elucidated. The Notch signaling pathway is involved in cell fate determination and has been implicated in proximal-distal patterning in the mammalian kidney. To investigate the role of Notch signaling in renal collecting duct development, we generated mice in which Mind bomb-1 (Mib1), an E3 ubiquitin ligase required for the initiation of Notch signaling, was specifically inactivated in the ureteric bud of the developing kidney.

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Notch signaling regulates lineage decisions at multiple stages of lymphocyte development, and Notch activation requires the endocytosis of Notch ligands in the signal-sending cells. Four E3 ubiquitin ligases, Mind bomb (Mib) 1, Mib2, Neuralized (Neur) 1, and Neur2, regulate the Notch ligands to activate Notch signaling, but their roles in lymphocyte development have not been defined. We show that Mib1 regulates T and marginal zone B (MZB) cell development in the lymphopoietic niches.

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Notch signaling is critical for the stemness of radial glial cells (RGCs) during embryonic neurogenesis. Although Notch-signal-receiving events in RGCs have been well characterized, the signal-sending mechanism by the adjacent cells is poorly understood. Here, we report that conditional inactivation of mind bomb-1 (mib1), an essential component for Notch ligand endocytosis, in mice using the nestin and hGFAP promoters resulted in complete loss of Notch activation, which leads to depletion of RGCs, and premature differentiation into intermediate progenitors (IPs) and finally neurons, which were reverted by the introduction of active Notch1.

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Signal transducer and activator of transcription 3 (STAT3) is a transcriptional factor that performs a broad spectrum of biological functions in response to various stimuli. However, no specific coactivator that regulates the transcriptional activity of STAT3 has been identified. Here we report that CR6-interacting factor 1 (Crif1) is a specific transcriptional coactivator of STAT3, but not of STAT1 or STAT5a.

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Background: The Notch signaling pathway is an evolutionarily conserved intercellular signaling module essential for cell fate specification that requires endocytosis of Notch ligands. Structurally distinct E3 ubiquitin ligases, Neuralized (Neur) and Mind bomb (Mib), cooperatively regulate the endocytosis of Notch ligands in Drosophila. However, the respective roles of the mammalian E3 ubiquitin ligases, Neur1, Neur2, Mib1, and Mib2, in mammalian development are poorly understood.

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