Heat shock protein 70 potentiates interferon alpha production by plasmacytoid dendritic cells: relevance for cutaneous lupus and vitiligo pathogenesis. (25th October 2017)

• Record Type: Journal Article
• Authors: Jacquemin, C.; Rambert, J.; Guillet, S.; Thiolat, D.; Boukhedouni, N.; Doutre, M.‐S.; Darrigade, A.‐S.; Ezzedine, K.; Blanco, P.; Taieb, A.; Boniface, K.; Seneschal, J.
• Is Part Of: British journal of dermatology. Volume 177:Number 5(2017)
• Page Start: 1367
• Page End: 1375
• Publication Date: 2017-10-25
• Subjects: Dermatology -- Periodicals; Skin -- Diseases -- Periodicals; 616.5
• DOI: 10.1111/bjd.15550
• Languages: English
• ISSNs: 0007-0963

Abstract

Summary: Background: Plasmacytoid dendritic cells (pDCs) are a subset of dendritic cells specialized in the production of type I interferon (IFN‐α/β) and involved in various cutaneous inflammatory and autoimmune disorders, such as cutaneous lupus erythematosus (CLE) and vitiligo. Heat shock proteins (HSPs) are molecular chaperones essential for maintaining cellular functions, but they can act as a danger signal during inflammation. Objectives: To decipher the role of HSP70 in the production of IFN‐α by pDCs in CLE and vitiligo. Methods: Expression of HSP70 and CD123 + pDCs was analysed by immunohistochemistry or immunofluorescence in CLE and vitiligo skin samples. Flow cytometry was performed to analyse expression of HSP70 receptors, activation markers on pDCs and DNA uptake by pDCs in the presence of HSP70. The impact of HSP70 on DNA‐induced IFN‐α secretion by pDCs was evaluated by enzyme‐linked immunosorbent assay (ELISA). The effect of IFN‐α on chemokine (C‐X‐C motif) ligand 9 (CXCL9)/10 gene and protein expression by keratinocytes was determined by real‐time polymerase chain reaction and ELISA. Results: Infiltration of pDCs in CLE and progressive vitiligo was primarily located in the epidermis, close to keratinocytes expressing HSP70. In vitro experiments revealed that the pDCs expressing HSP70 receptor Lox‐1 (lectin‐like oxidized low‐density lipoprotein‐receptor‐1) were able to aggregate HSP70. Exogenous HSP70 induced activation of pDCs and increased the uptake of exogenous DNA. Furthermore, HSP70 potentiated DNA‐induced IFN‐α production by pDCs. Finally, IFN‐α induced expression of CXCL9 and CXCL10 by keratinocytes. Conclusions: These data demonstrate that interaction between HSP70 and pDCs in CLE and vitiligo is a prerequisite for the enhancement of IFN‐α production, and could be an interesting target. Abstract : What's already known about this topic? Heat shock protein (HSP)70 is overexpressed in cutaneous lupus erythematosus (CLE) and vitiligo skin. Human plasmacytoid dendritic cells (pDCs) play a major role in inflammatory skin diseases such as CLE and vitiligo. HSPs are molecular chaperones that can act as danger signals in the context of inflammation. What does this study add? HSP70 potentially contributes to the development of skin inflammation in CLE and vitiligo through the induction of pDC activation and potentialization of interferon (IFN)‐α secretion. IFN‐α amplifies the inflammatory response by inducing expression of chemokine (C‐X‐C motif) ligands 9 and 10 by keratinocytes. What is the translational message? Targeting HSP70 could dampen the production of IFN‐α by pDCs. Targeting HSP70 could be an interesting approach to improve treatment of skin inflammatory diseases such as CLE and vitiligo. Linked Comment: Speeckaert and van Geel. Br J Dermatol 2017; 177 :1161–1162 . Respond to this article