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Kwon, Ho-Keun

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Kwon

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Ho-Keun

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Kwon, Ho-Keun

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Now showing 1 - 3 of 3
  • Publication

    Immunomodulatory effect of water soluble extract separated from mycelium of Phellinus linteus on experimental atopic dermatitis

    (BioMed Central, 2012) Hwang, Ji Sun; Kwon, Ho-Keun; Kim, Jung-Eun; Rho, Jeonghae; Im, Sin-Hyeog

    Background: Complementary and alternative medicine (CAM) is becoming a popular treatment for modulating diverse immune disorders. Phellinus linteus (P. linteus) as one of the CAMs has been used to modulate cancers, inflammation and allergic activities. However, little evidence has been shown about its underlying mechanism of action by which it exerts a beneficial role in dermatological disease in vivo. In this study, we examined the immunomodulatory effects of P. linteus on experimental atopic dermatitis (AD) and elucidated its action mechanism. Methods: The immunomodulatory effect of total extract of P. linteus on IgE production by human myeloma U266B1 cells was measured by ELISA. To further identify the effective components, P. linteus was fractionated into methanol soluble, water soluble and boiling water soluble extracts. Each extract was treated to U266B1 cells and primary B cells to compare their inhibitory effects on IgE secretion. To test the in vivo efficacy, experimental atopic dermatitis (AD) was established by alternative treatment of DNCB and house dust mite extract into BALB/c mice. Water soluble extract of P. linteus (WA) or ceramide as a positive control were topically applied to ears of atopic mouse every day for 2 weeks and progression of the disease was estimated by the following criteria: (a) ear thickness, clinical score, (b) serum total IgE, IgG and mite specific IgE level by ELSIA, (c) histological examination of ear tissue by H&E staining and (d) cytokine profile of total ear cells and CD4+ T cells by real time PCR and ELSIA. Results: Treatment of total extracts of P. linteus to U266B1 inhibited IgE secretion. Among the diverse extracts of P. linteus, water soluble extract of P. linteus (WA) significantly reduced the IgE production in primary B cells and B cell line U266B1. Moreover, treatment of WA reduced AD symptoms such as ear swelling, erythema, and dryness and decreased recruitment of lymphocyte into the inflamed site. Interestingly WA treatment significantly reduced IgE level without affecting IgG levels and also down-regulated the levels of pathogenic cytokines (IL-4, IL-13, IL-12 and IFN-γ) and chemokines (CCL17 and CCL22) involved in AD development. Conclusions: Our study indicates that protective effect of water soluble extract of P. linteus in atopic dermatitis is mediated by inhibiting IgE production and expression of AD associated pathogenic cytokines as well as chemokines, suggesting the beneficial effect of P. linteus to modulate allergic skin disease.

  • Publication

    Hair follicle melanocyte cells as a renewable source of melanocytes for culture and transplantation

    (2008) Kwon, Ho-Keun; Liu, Perry H.; Lew, Dae-Hyun; Nishimura, Emi; Orgill, Dennis

    Objective: Advances in melanocyte culture techniques have not yet led to reliable clinical methods for treating hypopigmentation disorders. We hypothesized that melanocytes harvested from plucked hair follicles may provide a renewable source of melanocytes for the treatment of hypopigmentation. Methods: Hairs with attached cells from the follicles were plucked from Yucatan pigs and implanted in a collagen-glycosaminoglycan matrix for either immediate or delayed implantation into full-thickness excisional porcine wounds. Wounds were allowed to heal and were biopsied at 2 and 4 weeks, respectively. Results: Fully healed wounds with transplanted hair follicles showed central areas of dark pigmentation corresponding to the location of implanted hair follicles. Corresponding collagen-glycosaminoglycan matrix wounds showed no central areas of pigmentation. Conclusions: Hair follicle--derived melanocytes may potentially serve as a renewable source of pigment-producing cells for treating hypopigmentation disorders.

  • Publication

    Different molecular complexes that mediate transcriptional induction and repression by FoxP3

    (2017) Kwon, Ho-Keun; Chen, Hui-Min; Mathis, Diane; Benoist, Christophe

    FoxP3 conditions the transcriptional signature and functional facets of regulatory T (Treg) cells. Its mechanism of action, whether as an activator or a repressor, remains unclear. Chromatin analysis shows that FoxP3 binds active enhancer elements, not repressed chromatin, around loci over- and under-expressed in Treg cells. We evaluated the impact of a FoxP3 mutation panel on transcriptional activity and interactions with DNA, transcriptional cofactors and chromatin. Computational integration, confirmed by biochemical interaction and size analyses, showed that FoxP3 exists in distinct multimolecular complexes. It is active and primarily an activator when complexed with the transcriptional co-factors RELA, IKZF2, and KAT5. In contrast, FoxP3 is inactive when complexed to EZH2, YY1 and IKZF3, where super-resolution microscopy shows this complex to partition to a peripheral region of the nucleus. Thus, FoxP3 acts in multimodal fashion to directly activate or repress transcription, in a context- and partner-dependent manner, to govern Treg cell phenotypes.