Publications by authors named "Jung Hwa Ko"

Article Synopsis
  • Mesenchymal stem/stromal cells (MSCs) play a crucial role in tissue maintenance and respond to microenvironment changes caused by injury, with Toll-like receptors (TLRs) acting as important sensors for these changes.
  • Research focused on the expression and role of TLR2 in MSCs, showing that its activation enhances MSC immunoregulatory and angiostatic functions in relation to monocytes/macrophages and in a mouse model of corneal inflammation.
  • The study identified aldo-keto reductase family 1 member C1 (AKR1C1) as a key gene induced by TLR2 activation, which protects MSCs from cell death, boosts the secretion of anti-inflammatory signals, and ultimately helps reduce inflammation
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Purpose: To investigate the toxicity of type I interferons (IFNs) on the ocular surface and assess their efficacy in ocular surface tumors.

Methods: We examined the effects of IFN-α2a, IFN-α2b and IFN-β on corneal epithelial cells and stromal fibroblasts in vitro as well as the impact of IFN-α2a on the ocular surface in mice. Additionally, we analyzed the therapeutic and adverse effects of topically administered IFN-α2a and IFN-α2b in patients with ocular surface tumors.

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Article Synopsis
  • The study explored how subconjunctival injections of aflibercept impact corneal blood vessel growth and specific immune cells in a mouse model.
  • Aflibercept led to a significant decrease in new blood vessel formation in the cornea compared to a control treatment with saline.
  • The treatment also lowered levels of certain pro-angiogenic and inflammatory markers in the cornea and reduced the presence of VEGFR-3CD11b immune cells without affecting VEGFR-2CD11b cell levels.
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Article Synopsis
  • MSCs (Mesenchymal stem/stromal cells) can change the immune response by influencing the development of specific immune cells, particularly within the context of ocular autoimmune inflammation.
  • Analysis using single-cell RNA sequencing identified seven different immune cell types within the MSC-induced population, highlighting the presence of myeloid-derived suppressor cells (MDSCs) that showed distinct gene expression patterns.
  • The study found that these MSC-induced MDSCs, characterized by the CSF-1R marker, effectively suppressed CD4 T cell activity and supported the expansion of regulatory T cells (Tregs), indicating their potential for therapeutic application in autoimmune conditions.
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Fucosylation plays a critical role in cell-to-cell interactions and disease progression. However, the effects of fucosylation on splenocytes and their interactions with T cells remain unclear. In this study, we aimed to explore the transcriptome profiles of splenocytes deficient in fucosyltransferase (FUT) 1, an enzyme that mediates fucosylation, and investigate their impact on the proliferation and differentiation of T cells.

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Despite accumulating evidence indicating a key role of interferon-γ (IFN-γ)-producing immune cells in ocular infection and immunity, little is known about the direct effects of IFN-γ on resident corneal cells or on the ocular surface. Here, we report that IFN-γ impacts corneal stromal fibroblasts and epithelial cells to promote inflammation, opacification, and barrier disruption on the ocular surface, leading to dry eye. Our results demonstrated that IFN-γ dose-dependently induced cytotoxicity, pro-inflammatory cytokine/chemokine production, and expression of major histocompatibility complex class II and CD40 in cultures of corneal stromal fibroblasts and epithelial cells while increasing myofibroblast differentiation of corneal stromal fibroblasts.

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Purpose: Pseudognaphalium affine (P. affine), a medicinal plant, has long been used to treat various diseases due to its astringent and vulnerary effects. These therapeutic benefits are largely attributed to high contents of phytochemicals, such as flavonoids and polyphenols, that have anti-inflammatory and tissue-protective activities.

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Background Aims: The Akt/mammalian target of rapamycin (mTOR) pathway in macrophages converges inflammatory and metabolic signals from multiple receptors to regulate a cell's survival, metabolism and activation. Although mesenchymal stromal cells (MSCs) are well known to modulate macrophage activation, the effects of MSCs on the Akt/mTOR pathway in macrophages have not been elucidated.

Methods: We herein investigated whether MSCs affect the Akt/mTOR complex 1 (mTORC1) pathway to regulate macrophage polarization.

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Background: Mounting evidence suggests that the immune system plays detrimental or protective roles in nerve injury and repair.

Main Body: Herein we report that both CD11bLy6G and CD11bLy6CLy6G myeloid cells are required to protect corneal nerves against sterile corneal injury. Selective depletion of CD11bLy6G or CD11bLy6CLy6G cells resulted in aggravation of corneal nerve loss, which correlated with IL-6 upregulation.

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To investigate the effect of fucosyltransferase (FUT) 1-mediated fucosylation on meibomian glands (MG), we first confirmed that FUT1 and its fucosylated products were expressed in the eyelid, conjunctiva and skin in wild-type (WT) mice, whereas their mRNA and protein levels were downregulated in Fut1 knock-out (KO) mice. We then evaluated age-dependent changes in the total and acinar areas of MG, meibocyte differentiation, lipid synthesis, and eyelid inflammation and oxidative stress in Fut1 KO and WT mice. Results show that both the total and acinar areas of MG were smaller in Fut1 KO mice than in WT mice in all evaluated age groups.

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Microbiota promotes or inhibits the pathogenesis of a range of immune-mediated disorders. Although recent studies have elucidated the role of gut microbiota in ocular disease, the effect of ocular microbiota remains unclear. Herein, we explored the role of ocular commensal bacteria in non-infectious corneal inflammation and angiogenesis in a mouse model of suture-induced corneal neovascularization.

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Fucosylation is involved in a wide range of biological processes from cellular adhesion to immune regulation. Although the upregulation of fucosylated glycans was reported in diseased corneas, its implication in ocular surface disorders remains largely unknown. In this study, we analyzed the expression of a fucosylated glycan on the ocular surface in two mouse models of dry eye disease (DED), the NOD.

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Mounting evidence indicates that microRNAs (miRNAs), including miR-146a, have an impact on the immunomodulatory activities of mesenchymal stem/stromal cells (MSCs). Suppression of inflammatory macrophage activation is one of the main immunomodulatory mechanisms of MSCs. Here, we investigated whether miR-146a in MSCs might play a role in the effects of MSCs on macrophage activation.

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Mesenchymal stem/stromal cells (MSCs) regulate immunity through myeloid-derived suppressor cells (MDSCs), which are a heterogeneous population of immature myeloid cells with phenotypic and functional diversity. Herein, we identified a distinct subset of MDSCs induced by MSCs in the BM under inflammatory conditions. MSCs directed the differentiation of Ly6Glo BM cells from CD11bhiLy6Chi cells to CD11bmidLy6Cmid cells both in cell contact-independent and -dependent manners upon GM-CSF stimulation in vitro and in mice with experimental autoimmune uveoretinitis (EAU).

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Fucosylation is a biological process that plays a critical role in multiple cellular functions from cell adhesion to immune regulation. Fucosyltransferases (FUTs) mediate fucosylation, and dysregulation of genes encoding FUTs is associated with various diseases. FUT1 and its fucosylated products are expressed in the ocular surface and ocular adnexa; however, the role of FUT1 in the ocular surface health and disease is yet unclear.

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The cross-talk between mesenchymal stem and stromal cells (MSCs) and macrophages is critical for the restoration of tissue homeostasis after injury. Here, we demonstrate a pathway through which MSCs instruct macrophages to resolve inflammation and preserve tissue-specific stem cells, leading to homeostasis in mice with autoimmune uveoretinitis and sterile-injury-induced corneal epithelial stem cell deficiency. Distinct from their conventional role in macrophage reprogramming to anti-inflammatory phenotype by a PGE2-dependent mechanism, MSCs enhance the phagocytic activity of macrophages, which partly depends on the uptake of MSC mitochondria-containing extracellular vesicles.

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The mammalian target of rapamycin (mTOR) signaling is critical to the regulation of stem cell maintenance and function in a cell-type and context-dependent manner. However, the effects of mTOR signaling on corneal epithelial stem cells (CESCs) under inflammatory conditions are not clear. Here, we demonstrate that mTOR inhibition with rapamycin promotes apoptosis of CESCs in a mouse model of sterile inflammation-induced CESC deficiency, and thereby aggravates the disease.

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Resolution of inflammation is an active process that leads to tissue homeostasis and involves multiple cellular and molecular mechanisms. Myeloid-derived suppressor cells (MDSCs) have recently emerged as important cellular components in the resolution of inflammation because of their activities to suppress T cell activation. In this article, we show that HLA-DRCD11bCD33CD14 human MDSCs and CD11bLy6GLy6C mouse MDSCs markedly increased in patients and mice during and before the resolution phase of autoimmune uveoretinitis.

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The cornea is a transparent tissue devoid of blood and lymphatic vessels. However, various inflammatory conditions can cause hemangiogenesis and lymphangiogenesis in the cornea, compromising transparency and visual acuity. Mesenchymal stem/stromal cells (MSCs) have therapeutic potentials in a variety of diseases because of anti-inflammatory properties.

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Purpose: Benzalkonium chloride (BAK), the most commonly used preservative in ophthalmic solutions, is known to cause toxicity in the corneal epithelium. In this study, we investigated the effects of 20% human serum in cultures of BAK-damaged human corneal epithelial cells (hCECs) and in patients with toxic corneal epitheliopathy induced by BAK-containing eye drops.

Methods: hCECs were exposed to various concentrations of BAK (0%, 0.

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The cells of the innate immune system, in addition to their capacity to elicit immunity, play a substantial role in immune tolerance induction. Our group has recently shown that a distinct subset of MHC IIB220CD11b suppressive macrophages is increased in the lung by intravenous (IV) administration of mesenchymal stem/stromal cells (MSC) and induces immune tolerance. Herein, we demonstrate that circulating CD11bLy6C monocytes are precursors to MHC IIB220CD11b macrophages in the lung and required for MSC-induced tolerance in a mouse model of experimental autoimmune uveitis (EAU).

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Mesenchymal stromal cells (MSCs) have therapeutic potential for various diseases because of their anti-inflammatory and immunosuppressive properties. However, the immunosuppressive microenvironment allows tumor cells to evade immune surveillance, whereas maintenance of inflammation is required for tumor development and progression. Hence, MSCs may promote or suppress tumors in a context-dependent manner.

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Glucocorticoid eye drops are one of the most widely used medications in ophthalmology. However, little is known about the effects of glucocorticoids on corneal epithelial cells that are directly exposed to topically-administered glucocorticoids. Here we investigated the effects of prednisolone, a synthetic glucocorticoid analogue frequently used in the clinic, on corneal epithelial cells.

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Excessive and prolonged activation of macrophages underlies many inflammatory and autoimmune diseases. To regulate activation and maintain homeostasis, macrophages have multiple intrinsic mechanisms, one of which is modulation through autophagy. Here we demonstrate that autophagy induction by rapamycin suppressed the production of IL-1β and IL-18 in lipopolysaccharide- and adenosine triphosphate-activated macrophages at the post-transcriptional level by eliminating mitochondrial ROS (mtROS) and pro-IL1β in a p62/SQSTM1-dependent manner.

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Telomeres are transcribed into long non-coding RNA, referred to as telomeric repeat-containing RNA (TERRA), which plays important roles in maintaining telomere integrity and heterochromatin formation. TERRA has been well characterized in HeLa cells, a type of cervical cancer cell. However, TERRA abundance and stability have not been examined in other cervical cancer cells, at least to the best of our knowledge.

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