Deregulation of epidermal stem cell niche contributes to pathogenesis of nonhealing venous ulcers

• Type of Material: Article
• Authors: Olivera Stojadinovic, University of Miami; Irena Pastar, University of Miami; Aron G. Nusbaum, University of Miami; Sasa Vukelic, Emory University; Agata Krzyzanowska, Hospital for Special Surgery; Marjana Tomic-Canic, University of Miami
• Language: English
• Date: 2014-03-01
• Publisher: Wiley: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2014 The Wound Healing Society.
• Final Published Version (URL): http://dx.doi.org/10.1111/wrr.12142
• Title of Journal or Parent Work: Wound Repair and Regeneration
• ISSN: 1067-1927
• Volume: 22
• Issue: 2
• Start Page: 220
• End Page: 227
• Grant/Funding Information: This work was supported by National Institutes of Health grants NR008029 and NR013881 (MTC); University of Miami SAC Award SAC 2013-19; and The Skin Disease Research Center, Department of Dermatology and Cutaneous Surgery at the University of Miami Miller School of Medicine.
• Keywords: SKIN; C-MYC; MOUSE EPIDERMIS; Surgery; Medicine, Research & Experimental; Science & Technology; HOMEOSTASIS; Dermatology; Life Sciences & Biomedicine; DIFFERENTIATION; EXPRESSION; DISTINCT; Research & Experimental Medicine; LEG ULCERS; HAIR FOLLICLE; ACTIVATION; Cell Biology
• Research Categories: Health Sciences, Medicine and Surgery

Abstract

The epidermis is maintained by epidermal stem cells (ESCs) that reside in distinct niches and contribute to homeostasis and wound closure. Keratinocytes at the nonhealing edges of venous ulcers (VUs) are healing-incompetent, hyperproliferative, and nonmigratory, suggesting deregulation of ESCs. To date, genes which regulate ESC niches have been studied in mice only. Utilizing microarray analysis of VU nonhealing edges, we identified changes in expression of genes harboring regulation of ESCs and their fate. In a prospective clinical study of 10 VUs, we confirmed suppression of the bone morphogenetic protein receptor (BMPR) and GATA binding protein 3 (GATA3) as well as inhibitors of DNA-binding proteins 2 and 4 (ID2 and ID4). We also found decreased levels of phosphorylated glycogen synthase kinase 3 (GSK3), nuclear presence of β-catenin, and overexpression of its transcriptional target, c-myc, indicating activation of the Wnt pathway. Additionally, we found down-regulation of leucine-rich repeats and immunoglobulin-like domains protein 1 (LRIG1), a gene important for maintaining ESCs in a quiescent state, and absence of keratin 15 (K15), a marker of the basal stem cell compartment suggesting local depletion of ESCs. Our study shows that loss of genes important for regulation of ESCs and their fate along with activation of β-catenin and c-myc in the VU may contribute to ESC deprivation and a hyperproliferative, nonmigratory healing incapable wound edge.