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Front Immunol. 2017 Feb 3;8:91. doi: 10.3389/fimmu.2017.00091. eCollection 2017.

Ultraviolet B Inhibits IL-17A/TNF-α-Stimulated Activation of Human Dermal Fibroblasts by Decreasing the Expression of IL-17RA and IL-17RC on Fibroblasts.

Author information

1
Department of Dermatology, The First Affiliated Hospital of Nanjing Medical University , Nanjing , China.
2
Department of Oncology, The First Affiliated Hospital of Nanjing Medical University , Nanjing , China.

Abstract

BACKGROUND:

Psoriasis is a chronic immune-mediated inflammatory disease, and a mixed Th1/Th17 cytokine environment plays a critical role in the pathogenesis of psoriasis. Dermal fibroblasts secrete certain cytokines such as IL-6, IL-8, and CXCL-1, contributing to the hyperproliferative state of the epidermis in psoriatic skin. Ultraviolet B (UVB) phototherapy is one of the most commonly used treatments in psoriasis but the influence of UVB on human dermal fibroblasts (HDFs) in psoriasis treatment is not completely understood.

OBJECTIVES:

We conducted this study to mimic a psoriatic microenvironment in order to investigate and illustrate the combined effects of UVB, IL-17A, and TNF-α on HDFs.

METHODS:

The cultured HDFs were obtained from foreskin samples and divided into four groups, as follows: control; IL-17A/TNF-α; UVB; and IL-17A/TNF-α + UVB. Cultured HDFs were irradiated with 30 mJ/cm2 UVB followed by addition of IL-17A/TNF-α and incubated for 24 h. We used real-time quantitative PCR, Western blot, ELISA analysis, and flow cytometry to examine gene and protein expression of related pro-inflammatory cytokines and chemokines and receptors.

RESULTS:

HDFs produced significant IL-6, IL-8, and CXCL-1 in response to IL-17A/TNF-α stimulation and UVB irradiation but UVB irradiation inhibited IL-17A/TNF-α-induced IL-6, IL-8, and CXCL-1 expression and downregulated the expression of IL-17RA and IL-17RC at both gene and protein levels. Additionally, UVB irradiation induced significant TGF-β1 protein secretion and expression of Smad3 mRNA and protein by HDFs. TGF-β1 significantly induced the expression of Smad3 mRNA and downregulated the IL-17RA and IL-17RC expression on HDFs.

CONCLUSION:

UVB irradiation inhibits IL-17A/TNF-α-induced IL-6, IL-8, and CXCL-1 production in HDFs by decreasing the expression of IL-17RA and IL-17RC on fibroblasts through TGF-β1/Smad3 signaling pathway, which reveals a new mechanism of the therapeutic action of UVB on psoriasis.

KEYWORDS:

IL-17; TGF-β; TNF-α; fibroblast; psoriasis; ultraviolet

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