Increased Expression Of Pro-inflammatory Cytokines And Periostin In Burn Eschar Pericytes
Alexander Evdokiou1, Stephanie Gierek1, Onur Kanisicak2, Richard Bodnar3, Latha Satish1.
1Shriners Hospitals for Children-Cincinnati, Cincinnati, OH, USA, 2Department of Pathology and Laboratory Medicine, University of Cincinnati, College of Medicine, Cincinnati, OH, USA, 3Veterans Affairs Medical Center, Pittsburgh, PA, USA.
BACKGROUND: Pericytes exhibit mesenchymal stem cell-like properties and have a key role in various fibrotic disease by contributing to the myofibroblast formation. Periostin is shown to exacerbate fibrosis in various organs. In this study, the influence of burn wound environment on the inflammatory status of pericytes and their effect on periostin deposition in skin wound stroma is determined. METHODS: Pericytes were isolated from discarded burn eschar and normal skin obtained from patients undergoing elective plastic surgery. RNA was isolated and subjected to RNA-seq and real-time RT-PCR analyses. Changes in protein levels were determined by immunohistochemistry, western blots, and ELISA. Data analyses were done using ANOVA and p<0.05 was considered statistically significant. RESULTS: We identified 443 statistically significant differentially expressed genes between normal- and burn eschar-derived pericytes. Five of the pro-inflammatory genes, namely IL-6, IL-1β, IL-1α, IL-8, and TNFαIP3, were upregulated and one pro-inflammatory gene (CXCL-14) was downregulated in burn pericytes. Two anti-inflammatory genes (NFkBIZ and NFkBIα) were upregulated in burn pericytes. Western blots showed increased basal expression of NFkB in burn pericytes. ELISA confirmed upregulation of IL-6 and IL-8 at the basal level in burn eschar pericytes compared to normal skin pericytes (p<0.05). An increase in periostin in burn eschar tissues and pericytes was determined both at the mRNA and protein levels compared to normal skin and pericytes. CONCLUSIONS: We report for the first time that burn eschar pericytes are inflammatory and may contribute to burn scar contractures and fibrosis by increasing the expression of periostin, a protein produced by myofibroblasts in cardiac fibrosis.
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