• Molecules and Cells
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• v.44 no.12
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• pp.861-878
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• 2021

The human genome contains many retroviral elements called human endogenous retroviruses (HERVs), resulting from the integration of retroviruses throughout evolution. HERVs once were considered inactive junk because they are not replication-competent, primarily localized in the heterochromatin, and silenced by methylation. But HERVs are now clearly shown to actively regulate gene expression in various physiological and pathological conditions such as developmental processes, immune regulation, cancers, autoimmune diseases, and neurological disorders. Recent studies report that HERVs are activated in patients suffering from coronavirus disease 2019 (COVID-19), the current pandemic caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection. In this review, we describe internal and external factors that influence HERV activities. We also present evidence showing the gene regulatory activity of HERV LTRs (long terminal repeats) in model organisms such as mice, rats, zebrafish, and invertebrate models of worms and flies. Finally, we discuss several molecular and cellular pathways involving various transcription factors and receptors, through which HERVs affect downstream cellular and physiological events such as epigenetic modifications, calcium influx, protein phosphorylation, and cytokine release. Understanding how HERVs participate in various physiological and pathological processes will help develop a strategy to generate effective therapeutic approaches targeting HERVs.

• IMMUNE NETWORK
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• v.23 no.2
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• pp.12.1-12.17
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• 2023

Ssu72, a dual-specificity protein phosphatase, not only participates in transcription biogenesis, but also affects pathophysiological functions in a tissue-specific manner. Recently, it has been shown that Ssu72 is required for T cell differentiation and function by controlling multiple immune receptor-mediated signals, including TCR and several cytokine receptor signaling pathways. Ssu72 deficiency in T cells is associated with impaired fine-tuning of receptor-mediated signaling and a defect in CD4⁺ T cell homeostasis, resulting in immune-mediated diseases. However, the mechanism by which Ssu72 in T cells integrates the pathophysiology of multiple immune-mediated diseases is still poorly elucidated. In this review, we will focus on the immunoregulatory mechanism of Ssu72 phosphatase in CD4⁺ T cell differentiation, activation, and phenotypic function. We will also discuss the current understanding of the correlation between Ssu72 in T cells and pathological functions which suggests that Ssu72 might be a therapeutic target in autoimmune disorders and other diseases.

• IMMUNE NETWORK
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• v.21 no.3
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• pp.19.1-19.18
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• 2021

Clinical and molecular phenotypes of asthma are complex. The main phenotypes of adult asthma are characterized by eosinophil and/or neutrophil cell dominant airway inflammation that represent distinct clinical features. Upper and lower airways constitute a unique system and their interaction shows functional complementarity. Although human upper airway contains various indigenous commensals and opportunistic pathogenic microbiome, imbalance of this interactions lead to pathogen overgrowth and increased inflammation and airway remodeling. Competition for epithelial cell attachment, different susceptibilities to host defense molecules and antimicrobial peptides, and the production of proinflammatory cytokine and pattern recognition receptors possibly determine the pattern of this inflammation. Exposure to environmental factors, including infection, air pollution, smoking is commonly associated with asthma comorbidity, severity, exacerbation and resistance to anti-microbial and steroid treatment, and these effects may also be modulated by host and microbial genetics. Administration of probiotic, antibiotic and corticosteroid treatment for asthma may modify the composition of resident microbiota and clinical features. This review summarizes the effect of some environmental factors on the upper respiratory microbiome, the interaction between host-microbiome, and potential impact of asthma treatment on the composition of the upper airway microbiome.

• Biomolecules & Therapeutics
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• v.32 no.4
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• pp.460-466
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• 2024

Asthma is characterized by chronic inflammation and respiratory tract remodeling. Peroxisome proliferator-activated receptors (PPARs) play important roles in the pathogenesis and regulation of chronic inflammatory processes in asthma. The role of PPARγ has been studied using synthetic PPARγ agonists in patients with asthma. However, involvement of PPARα/δ has not been studied in asthma. In the present study, we investigated if elafibranor, a PPARα/δ dual agonist, can modulate ovalbumin (OVA)-induced allergic asthma, which is a potential drug candidate for non-alcoholic fatty liver in obese patients. Elafibranor suppresses antigen-induced degranulation in RBL-2H3 mast cells without inducing cytotoxicity in vitro. In mice with OVA-induced allergic asthma, the administration of elafibranor suppressed OVA-induced airway hyper-responsiveness at a dose of 10 mg/kg. Elafibranor also suppressed the OVA-induced increase in immune cells and pro-inflammatory cytokine production in the bronchoalveolar lavage fluid (BALF). Histological studies suggested that elafibranor suppressed OVA-induced lung inflammation and mucin hyper-production in the bronchial airways. In addition, elafibranor suppressed OVA-induced increases in serum immunoglobulin E and IL-13 levels in BALF. Conversely, the present study suggests that elafibranor has the potential for use in patients with allergic asthma.

• Molecules and Cells
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• v.39 no.11
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• pp.790-796
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• 2016

Dental pulp is a highly vascularized tissue requiring adequate blood supply for successful regeneration. In this study, we investigated the functional role of stem cells from human exfoliated deciduous teeth (SHEDs) as a perivascular source for in vivo formation of vessel-like structures. Primarily isolated SHEDs showed mesenchymal stem cell (MSC)-like characteristics including the expression of surface antigens and in vitro osteogenic and adipogenic differentiation potentials. Moreover, SHEDs were positive for NG2, ${\alpha}$-smooth muscle actin (SMA), platelet-derived growth factor receptor beta ($PDGFR{\beta}$), and CD146 as pericyte markers. To prove feasibility of SHEDs as perivascular source, SHEDs were transplanted into immunodeficient mouse using Matrigel with or without human umbilical vein endothelial cells (HUVECs). Transplantation of SHEDs alone or HUVECs alone resulted in no formation of vessel-like structures with enough red blood cells. However, when SHEDs and HUVECs were transplanted together, extensive vessel-like structures were formed. The presence of murine erythrocytes within lumens suggested the formation of anastomoses between newly formed vessel-like structures in Matrigel plug and the host circulatory system. To understand underlying mechanisms of in vivo angiogenesis, the expression of angiogenic cytokine and chemokine, their receptors, and MMPs was compared between SHEDs and HUVECs. SHEDs showed higher expression of1VEGF, SDF-$1{\alpha}$, and $PDGFR{\beta}$ than HUVECs. On the contrary, HUVECs showed higher expression of VEGF receptors, CXCR4, and PDGF-BB than SHEDs. This differential expression pattern suggested reciprocal interactions between SHEDs and HUVECs and their involvement during in vivo angiogenesis. In conclusion, SHEDs could be a feasible source of perivascular cells for in vivo angiogenesis.

• Journal of Ginseng Research
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• v.32 no.1
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• pp.39-47
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• 2008

UV irradiation causes skin-aging involving coarse wrinkles, thickening, dyspigmentation, and rough skin surface. These phenomena in complex skin tissue is controlled with receptor of cell surface growth factor and cytokine receptors. The activation of receptors induces multiple downstream signaling pathways including expression of MMPs (matrix metalloproteinases). This study was aimed to elucidate the mechanism for anti-wrinkle activity of Korean red ginseng, Torilis fructus and Corni fructus mixture (KTNG0345). In this animal study, we have investigated decreasing effects of Korean red ginseng mixture on MMP-3 synthesis through diminishing $TNF-{\alpha}$ signaling that express MMP-1, -3, and -9. c-Jun and c-fos as a component of transcription factor AP-1 (activator protein-1) were analyzed the expression level using real time PCR and western blotting. c-Jun was decreased dose dependent manner both gene and protein level where as cfos was not changed. In upstream, JNK and PAK was not changed, but p38 was decreased in down stream. MMP-3, final product in this pathway was significantly decreased in dose dependent manner. These results suggest that Korean red ginseng mixture have a anti-wrinkle activity through $TNF-{\alpha}$ mediated MMPs expression pathway.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.4
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• pp.413-421
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• 2014

Corticotropin-releasing factor (CRF) is involved in the stress response and there is increasing evidence that stress influences skin disease such as hair loss. In cultured human hair follicles, CRF inhibits hair shaft elongation, induces premature regression and promotes the apoptosis of hair matrix keratinocytes. We investigated whether CRF influences the dermal papilla cells (DPC) that play pivotal roles in hair growth and cycling. Human DPCs were treated with CRF, adrenocorticotropic hormone (ACTH) and cortisol, key stress hormones along the hypothalamic-pituitary -adrenal (HPA) axis for 1-24 h. Interestingly, CRF modulated the expression of cytokines related to hair growth (KGF, Wnt5a, $TGF{\beta}-2$, Nexin) and increased cAMP production in cultured DPCs. CRF receptors were down-regulated by negative feedback systems. Pretreatment of CRF receptor antagonists or protein kinase A (PKA) inhibitor prevented the CRF-induced modulation. Since the CRF induces proopiomelanocortin (POMC) expression through the cAMP/PKA pathway, we analyzed POMC mRNA. CRF stimulated POMC expression in cultured human DPCs, yet we were unable to detect ACTH levels by western blot. These results indicate that CRF operates within DPCs through CRF receptors along the classical CRF signaling pathway and CRF receptor antagonists could serve as potential therapeutic and cosmetic agents for stress-induced hair loss.

• Journal of Life Science
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• v.33 no.12
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• pp.1062-1073
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• 2023

Although depression is a common psychiatric disorder that negatively affects individuals and societies, its exact pathogenesis is not well understood. Stress is a major risk factor for depression and is known to increase susceptibility by triggering inflammation. Indeed, many preclinical and clinical studies have suggested a strong link between depression and inflammation. Depression is associated with increased levels of pro-inflammatory cytokines, such as interleukin (IL-)1β, IL-6, IL-12, tumor necrosis factor-α, and interferon-γ, and decreased levels of the anti-inflammatory IL-4, IL-10, and transforming growth factor-β. Administering pro-inflammatory cytokines causes depression-like behaviors in rodents. Conversely, administering anti-inflammatory drugs appears to ameliorate depressive symptoms. Although the importance of inflammation as a mediator of depression has been demonstrated, the mechanisms by which inflammation is activated in depression remain unclear. To address this issue, recent studies have focused on the importance of stress-induced sterile inflammation. Sterile inflammation refers to the activation of inflammatory processes due to physical and/or psychological stress in the absence of pathogens. Stress promotes the release of endogenous factors known as damage-associated molecular patterns (DAMPs), thereby triggering sterile inflammation. In turn, DAMPs are recognized by pattern recognition receptors, leading to the production of pro-inflammatory cytokines. Here, we review the role of DAMPs in depression based on preclinical and clinical evidence on the dysregulation of sterile inflammation.

• Clinical and Experimental Pediatrics
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• v.56 no.4
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• pp.151-158
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• 2013

Purpose: We investigated the mRNA levels of peroxisome proliferator-activated receptor (PPAR)-${\alpha}$, PPAR-${\gamma}$, adipokines, and cytokines in the lung tissue of lean and obese mice with and without ovalbumin (OVA) challenge, and the effect of rosiglitazone, a PPAR-${\gamma}$ agonist. Methods: We developed 6 mice models: OVA-challenged lean mice with and without rosiglitazone; obese mice with and without rosiglitazone; and OVA-challenged obese mice with and without rosiglitazone. We performed real-time polymerase chain reaction for leptin, leptin receptor, adiponectin, vascular endothelial growth factor (VEGF), tumor necrosis factor (TNF)-${\alpha}$, transforming growth factor (TGF)-${\beta}$, PPAR-${\alpha}$ and PPAR-${\gamma}$ from the lung tissue and determined the cell counts and cytokine levels in the bronchoalveolar lavage fluid. Results: Mice with OVA challenge showed airway hyperresponsiveness. The lung mRNA levels of PPAR${\alpha}$ and PPAR-${\gamma}$ increased significantly in obese mice with OVA challenge compared to that in other types of mice and decreased after rosiglitazone administeration. Leptin and leptin receptor expression increased in obese mice with and without OVA challenge and decreased following rosiglitazone treatment. Adiponectin mRNA level increased in lean mice with OVA challenge. Lung VEGF, TNF-${\alpha}$, and TGF-${\beta}$ mRNA levels increased in obese mice with and without OVA challenge compared to that in the control mice. However, rosiglitazone reduced only TGF-${\beta}$ expression in obese mice, and even augmented VEGF expression in all types of mice. Rosiglitazone treatment did not reduce airway responsiveness, but increased neutrophils and macrophages in the bronchoalveolar lavage fluid. Conclusion: PPAR-${\alpha}$ and PPAR-${\gamma}$ expressions were upregulated in the lung tissue of OVA-challenged obese mice however, rosiglitazone treatment did not downregulate airway inflammation in these mice.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.635-647
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• 1995

Human polymorphonuclear leukocytes(PMN) constitute a first line of defense against all forms of injury and microbial challenge, which share a common cell lineage with macrophage. Microbial component LPS activates macrophages to produce IL-1, MIP-1${\alpha}$, -1${\beta}$, TNF-${\alpha}$ and IL-6, etc. Those cytokines have autocrine function to the macrophages, and paracrine function to other cell such as PMN and affect them to produce some biological functions. Having a responsive homogeneous cell line, HL-60, offers us the possibility of studying extensively on the function of PMN, which were not possible previously with peripheral PMN, due to the short-lived nature and difficulty of getting a purified PMN. In the present study, I performed MIP-1 receptor binding assay using HL-60 cell and human peripheral PMN. Also, in vitro antimicrobial assay was performed using differentiated or undifferentiated HL-60 cell. Differentiation was induced by treatment with 500 M of $N^6,O^2-dibutyryl$ adenosine 3'5' cyclic monophosphate(dbcAMP) (PMN-like cell), or 20ng/ml of 12-O-tetradecanoylphorbol-13-acetate(TPA) (macrophage/monocyte-like cell). Receptors for MIP-1${\alpha}$ were identified on dbcAMP-treated HL-60 as well as peripheral PMN. However, bound radioactive MIP-1${\alpha}$ on differentiated HL-60 was much higher than that of peripheral PMN, which suggest receptor number of differentiated HL-60 cell is higher than that of peripheral PMN. Although both of TPA and dbcAMP treatment significantly enhanced antimicrobial action of HL-60 cell, dbcAMP-treated cell(PMN-like HL-60) killed S.aureus more effectively in this experiment. TPA or dbcAMP treatment significantly enhanced antimicrobial action of undifferentiated HL-60 cell. MIP-1${\alpha}$ further increased enhancing effect of TPA or dbcAMP. IL-1${\alpha}$, however, increased only dbcAMP-induced enhancing effect of antimicrobial action of HL-60 cell. These results suggest that differentiated HL-60 cell could replace peripheral PMN in analysis of various biological functions of cytokines on PMN cell.