Carren Sy Hau

The University of Tokyo, Tokyo, Tokyo-to, Japan

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Publications (3)16.88 Total impact

  • Article: P2Y6 receptor signaling pathway mediates inflammatory responses induced by monosodium urate crystals.
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    ABSTRACT: Gout occurs in individuals with hyperuricemia when monosodium urate (MSU) crystals precipitate in tissues and induce acute inflammation via phagocytic cells such as monocytes. MSU crystals have been demonstrated in skin diseases such as tophaceous gout or psoriasis; however, the importance of MSU crystals in the skin is totally unknown. In this study, we found that MSU crystals, through P2Y(6) receptors, stimulated normal human keratinocytes (NHK) to produce IL-1α, IL-8/CXCL8, and IL-6. P2Y(6) receptor expression increased in MSU-stimulated NHK. Both P2Y(6)-specific antagonist and P2Y(6) antisense oligonucleotides significantly inhibited the production of IL-1α, IL-8/CXCL8, and IL-6 by NHK. Similarly, the P2Y(6)-specific antagonist completely inhibited the MSU-induced production of IL-1β by THP-1 cells, a human monocytic cell line. Remarkably, the P2Y(6)-specific antagonist significantly reduced neutrophil influx in both mouse air pouch and peritonitis models. Thus, these results indicate that the P2Y(6) receptor signaling pathway may be a potential therapeutic target for MSU-associated inflammatory diseases, such as tophaceous gout.
    The Journal of Immunology 11/2011; 188(1):436-44. · 5.79 Impact Factor
  • Article: High calcium, ATP, and poly(I:C) augment the immune response to β-glucan in normal human epidermal keratinocytes.
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    ABSTRACT: β-Glucans are pathogen-associated molecular patterns of fungi such as Candida albicans. Here, we studied their effects on normal human epidermal keratinocytes (NHEKs) from neonatal foreskin, and with high calcium to induce keratinocyte differentiation, danger signals, and pathogen-associated compounds such as adenosine 5'-triphosphate (ATP), poly(I:C), and lipopolysaccharide (LPS). β-Glucan stimulation significantly increased IL-8, IL-6, and IL-1α production by NHEKs. Well-differentiated NHEKs produced elevated IL-8 levels, whereas ATP, a danger signal, significantly increased IL-8 and IL-6 production, and the pathogen-associated compound, poly(I:C), augmented IL-1α production by β-glucan-stimulated NHEKs. No response to LPS from Escherichia coli was seen. Dectin-1 is known as the major receptor for β-glucans on phagocytes and dendritic cells. Dectin-1 mRNA was detected in NHEKs by reverse transcription-PCR. Flow-cytometric analyses confirmed the NHEK cell surface expression of dectin-1. Immunoblotting showed that β-glucan induced dual phosphorylation of p44/42 mitogen-activated protein kinase (MAPK) (extracellular signal-regulated kinase (ERK)1/2), and p38 MAPK in NHEKs; these signaling pathways are known to be associated with dectin-1. Treatment with the ERK inhibitor PD98059 and with the p38 kinase inhibitor SB203580 effectively suppressed β-glucan-induced IL-8 production by NHEKs. Thus, high calcium, ATP, and poly(I:C) augment the cytokine and chemokine production by β-glucan-stimulated NHEKs. Dectin-1 is present on NHEKs and may have an important role in cell response to β-glucan.
    Journal of Investigative Dermatology 07/2011; 131(11):2255-62. · 6.31 Impact Factor
  • Article: Identification of a novel marker for dendritic cell maturation, mouse transmembrane protein 123.
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    ABSTRACT: Dendritic cells (DCs) are a group of professional antigen-presenting cells, and many genes are known to be associated with their maturation. We compared the transcriptional profiles of immature and mature mouse Langerhans cells using the suppressive, subtractive hybridization method and identified a novel gene of unknown function, termed herein transmembrane protein 123 (Tmem123), of which mRNA expression was enhanced in mature but not in immature Langerhans cells. Its expression was also enhanced in other mature DCs such as bone marrow-derived DCs (BMDCs) and splenic DCs. Interestingly, CD40 expression was up-regulated on mature BMDCs cultured with colchicine concurrently with the enhanced expression of Tmem123 compared with that of fresh BMDCs. Furthermore, the expression of CD40 was enhanced on Tmem123-transfected DC2.4 cells, a mouse BMDC-derived cell line, compared with that on mock-transfected DC2.4 cells. This enhancement of CD40 expression did not occur after deletion of lysosome/endosome targeting YXXϕ motifs (where X is any amino acid and ϕ is a bulky hydrophobic amino acid) in the Tmem123 cytoplasmic tail. By stimulation with anti-CD40 monoclonal antibody, these transfectants secreted an increased amount of IL-12/23 p40 compared with mock-transfected DC2.4 cells. Thus, our study demonstrates that Tmem123 may be used as a new maturation marker in DCs and that this molecule may be closely associated with the cell surface expression of CD40.
    Journal of Biological Chemistry 10/2010; 285(41):31876-84. · 4.77 Impact Factor