Regulation of fibroblast activity by keratinocytes, TGF-β and IL-1α: studies in two- and three dimensional in vitro models
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Dysregulated wound healing is commonly associated with excessive fibrosis. Connective tissue growth factor (CTGF/CCN2) is characteristically overexpressed in fibrotic diseases and stimulated by transforming growth factor-β (TGF-β) in dermal fibroblasts. Reepithelialisation and epidermal wound coverage counteract excessive scar formation. We have previously shown that interleukin-1α (IL-1α) derived from keratinocytes conteracts TGF-β-stimulated CTGF-expression. The aim of this thesis was to further explore the effects of keratinocytes and IL-1α on gene and protein expression, as well as pathways, in TGF-β stimulated fibroblasts. Fibroblasts were studied in vitro by conventional two dimensional cell culture models and in a three dimensional keratinocyte-fibroblast organotypic skin culture model.
The results showed that IL-1 suppresses basal and TGF-β-induced CTGF mRNA and protein, involving a possible TAK1 mechanism. Keratinocytes regulate the expression of fibroblast genes important for the turnover of the extracellular matrix. Most of the genes analysed (11/13) were regulated by TGF-β and counter regulated by keratinocytes. The overall results support a view that keratinocytes regulate fibroblasts to act catabolically (anti-fibrotic) on the extracellular matrix.
Transcriptional microarray and gene set enrichment analysis showed that antagonizing effects of IL-1α on TGF-β were much more prominent than the synergistic effects. The most confident of these pathways was the interferon signaling, which were inhibited by TGF-β and activated by IL-1α. A proteomics study confirmed that IL-1α preferentially conteracts TGF-β effects. Six new fibroblast proteins involved in synthesis/ regulation were identified, being regulated by TGF-β and antagonized by IL-1α. Pathway analysis confirmed counter-regulation of interferon signaling by the two cytokines. These findings have implications for understanding the role of fibroblasts for inflammatory responses and development of fibrosis in the skin.
Place, publisher, year, edition, pages
Örebro: Örebro university , 2016. , 83 p.
Örebro Studies in Medicine, ISSN 1652-4063 ; 133
Fibroblast, Keratinocyte, TGF-β, IL-1α, coculture, fibrosis CTGF/CNN 2, dermal, organotypic culture
Other Basic Medicine
IdentifiersURN: urn:nbn:se:oru:diva-48225ISBN: 978-91-7529-120-8OAI: oai:DiVA.org:oru-48225DiVA: diva2:902824
2016-03-18, Universitetssjukhuset, Wilandersalen, Södra Grev Rosengatan, Örebro, 09:00 (English)
Törmä, Hans, Professor
Ivarsson, Mikael, DocentBengtsson, Torbjörn, Professor
List of papers