Publications (27) View all
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Article: IFN-α enhances IL-22 receptor expression in keratinocytes: a possible role in the development of psoriasis.
Journal of Investigative Dermatology 02/2012; 132(7):1933-5. · 6.31 Impact Factor -
Article: Interactions between myofibroblast differentiation and epidermogenesis in constructing human living skin equivalents.
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ABSTRACT: During skin wounding and healing, skin homeostasis is interrupted. How the altered epithelial-mesenchymal interactions influence scar formation and epidermogenesis should be investigated using three-dimensional models that are similar to in vivo structures. In this study, we assessed the effects of epithelial-mesenchymal interactions on myofibroblast differentiation and how myofibroblasts influence epidermogenesis using a human living skin equivalent (LSE) model. We constructed a fibroblast-populated type I collagen gel upon which LSEs were formed by seeding with normal human keratinocytes. Samples of the collagen gel and LSEs were collected at different time points. Myofibroblast differentiation, epidermal differentiation, and proliferation status were investigated immunohistochemically. Several measures were taken to suppress α-smooth muscle actin (α-SMA) expression to determine the effects of myofibroblasts on epidermogenesis, including the addition of basic fibroblast growth factor or a transformation growth factor-β (TGF-β) kinase inhibitor to the culture medium and the inclusion of an amniotic membrane (AM) in the dermal matrix. The myofibroblast/fibroblast ratio in the fibroblast-populated collagen gel kept rising during culture. In the LSEs, most fibroblasts were α-SMA-negative, except for those along the dermal-epidermal junction. The suppression of α-SMA expression enhanced epidermal differentiation and decreased TGF-β1 expression in the epidermis. The inhibition of TGF-β kinase completely suppressed α-SMA expression in the dermal matrix. Epidermogenesis suppressed α-SMA expression in the fibroblast-rich dermal matrix, except near the dermal-epidermal junction. The α-SMA-positive cells at the dermal-epidermal junction contributed to the hyperproliferative phenotype of the epidermis. In contrast, the hyperproliferative epidermis expressed more TGF-β1, which is responsible for myofibroblast differentiation.Journal of dermatological science 11/2011; 65(1):50-7. · 3.71 Impact Factor -
Article: Nuclear translocation of phosphorylated STAT3 regulates VEGF-A-induced lymphatic endothelial cell migration and tube formation.
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ABSTRACT: Vascular endothelial growth factor (VEGF) is an endothelial cell-specific growth factor that regulates endothelial functions, and signal transducers and activators of transcription (STATs) are known to be important during VEGF receptor signaling. The aim of this study was to determine whether STAT3 regulates VEGF-induced lymphatic endothelial cell (LEC) migration and tube formation. VEGF-A (33 ng/ml) enhanced LEC migration by 2-fold and increased tube length by 25% compared with the control, as analyzed using a Boyden chamber and Matrigel assay, respectively. Western blot analysis and immunostaining revealed that VEGF-A induced the nuclear translocation of phosphorylated STAT3 in LECs, and this translocation was blocked by the transfection of LECs with an adenovirus vector expressing a dominant-negative mutant of STAT3 (Ax-STAT3F). Transfection with Ax-STAT3F also almost completely inhibited VEGF-A-induced LEC migration and tube formation. These results indicate that STAT3 is essential for VEGF-A-induced LEC migration and tube formation and that STAT3 regulates LEC functions.Biochemical and Biophysical Research Communications 08/2011; 412(3):441-5. · 2.48 Impact Factor -
Article: Mite allergen is a danger signal for the skin via activation of inflammasome in keratinocytes.
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ABSTRACT: Atopic dermatitis (AD) is a chronic inflammatory skin disorder caused by multiple factors. Among them, house dust mite (HDM) allergens are important in the development of AD. In airway allergy, HDM allergens activate innate immunity. However, information regarding the activation of innate immunity by HDM allergens in the skin is limited. The inflammasome is a key regulator of pathogen recognition and inflammation. We investigated whether HDM allergens activate the inflammasome in epidermal keratinocytes. Keratinocytes were stimulated with Dermatophagoides pteronyssinus, and the activation of caspase-1 and secretion of IL-1β and IL-18 were examined. Formation of the inflammasome was studied by analyzing the subcellular distributions of inflammasome proteins. The importance of specific inflammasome proteins was studied by knocking down their expression through transfection of keratinocytes with lentiviral particles carrying short hairpin RNAs (shRNAs). D pteronyssinus activated caspase-1 and induced caspase-1-dependent release of IL-1β and IL-18 from keratinocytes. Moreover, D pteronyssinus stimulated assembly of the inflammasome by recruiting apoptosis-associated specklike protein containing a caspase-recruitment domain (ASC), caspase-1, and nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin-domain containing 3 (NLRP3) to the perinuclear region. Finally, infection with lentiviral particles carrying ASC, caspase-1, or NLRP3 shRNAs suppressed the release of IL-1β and IL-18 from the keratinocytes. Activation of the NLRP3 inflammasome by D pteronyssinus was dependent on cysteine protease activity. House dust mite allergens are danger signals for the skin. In addition, HDM-induced activation of the NLRP3 inflammasome may play a pivotal role in the pathogenesis of AD.The Journal of allergy and clinical immunology 01/2011; 127(3):806-14.e1-4. · 9.17 Impact Factor -
Article: PPARγ mediates innate immunity by regulating the 1α,25-dihydroxyvitamin D3 induced hBD-3 and cathelicidin in human keratinocytes.
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ABSTRACT: Production of antimicrobial peptides (AMPs) is the primary mechanism by which skin innate immunity protects against infection. Hormonally active vitamin D3 (1α,25-dihydroxyvitamin D3; 1,25D₃) is a vital regulator of skin innate immunity, and has been shown to increase the expression and function of AMPs. PPARγ is a ligand-activated nuclear receptor and plays a role in keratinocyte differentiation and cutaneous homeostasis. In this study, we investigate whether 1,25D₃-activated PPARγ signaling regulates AMP expression in keratinocytes. Subconfluent keratinocytes were treated with 1,25D₃ for the indicated times. The mRNA and protein levels of AMPs were detected by RT-PCR and Western blot, and the DNA binding activation of PPARγ, VDRE and AP-1 was investigated by EMSA. To examine the role of PPARγ, the recombinant adenovirus carrying a dominant-negative form of PPARγ (dn-PPARγ) was constructed and transfected into keratinocytes. We show here that 1,25D₃ significantly enhances hBD-3 and cathelicidin expression in keratinocytes. Expression of dn-PPARγ did not affect binding to the vitamin D-responsive element (VDRE), which is crucial for cathelicidin induction by VD3; however, it did decrease 1,25D₃ induction of both hBD-3 and cathelicidin. Inhibition of the p38, ERK, and JNK signaling pathways blocked hBD-3 expression, whereas only p38 inhibition suppressed cathelicidin induction. dn-PPARγ had no effect on ERK and JNK activity, but inhibited p38 phosphorylation and suppressed 1,25D₃-induced AP-1 activation via effects on Fra1 and c-Fos proteins. In conclusion, PPARγ regulates the 1,25D₃-induced hBD-3 and cathelicidin expression in keratinocytes through the regulation of AP-1 and p38 activity.Journal of dermatological science 10/2010; 60(3):179-86. · 3.71 Impact Factor
