To Control Site-Specific Skin Gene Expression, Autocrine Mimics Paracrine Canonical Wnt Signaling and Is Activated Ectopically in Skin Disease

Dongwon Kim, M. Zulfiquer Hossain, Ashley Nieves, Lihong Gu, Tabetha S. Ratliff, Seung Mi Oh, Angela Park, Seunghyun Han, Nicole B. Yang, Ji Qi, Janis M Taube, Sewon Kang, Luis Garza

Research output: Contribution to journalArticle

Abstract

Despite similar components, the heterogeneity of skin characteristics across the human body is enormous. It is classically believed that site-specific fibroblasts in the dermis control postnatal skin identity by modulating the behavior of the surface-overlying keratinocytes in the epidermis. To begin testing this hypothesis, we characterized the gene expression differences between volar (ventral; palmoplantar) and nonvolar (dorsal) human skin. We show that KERATIN 9 (KRT9) is the most uniquely enriched transcript in volar skin, consistent with its etiology in genetic diseases of the palms and soles. In addition, ectopic KRT9 expression is selectively activated by volar fibroblasts. However, KRT9 expression occurs in the absence of all fibroblasts, although not to the maximal levels induced by fibroblasts. Through gain-of-function and loss-of-function experiments, we demonstrate that the mechanism is through overlapping paracrine or autocrine canonical WNT-β-catenin signaling in each respective context. Finally, as an in vivo example of ectopic expression of KRT9 independent of volar fibroblasts, we demonstrate that in the human skin disease lichen simplex chronicus, WNT5a and KRT9 are robustly activated outside of volar sites. These results highlight the complexities of site-specific gene expression and its disruption in skin disease.

Original languageEnglish (US)
Pages (from-to)1140-1150
Number of pages11
JournalAmerican Journal of Pathology
Volume186
Issue number5
DOIs
StatePublished - May 1 2016

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ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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