Induction of phenotype modifying cytokines by FERMT1 mutations

✍ Scribed by Anja Heinemann; Yinghong He; Elena Zimina; Melanie Boerries; Hauke Busch; Nadja Chmel; Thorsten Kurz; Leena Bruckner-Tuderman; Cristina Has

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 592 KB
• Volume: 32
• Category: Article
• ISSN: 1059-7794
• DOI: 10.1002/humu.21449

✦ Synopsis

Kindler syndrome (KS) is a progressive skin disorder caused by FERMT1 mutations. Early in life, KS manifests as a mechanobullous disease reflecting diminished cell adhesion, but the mechanisms of its later phenotypic features, progressive poikiloderma, and mucocutaneous fibrosis, remain elusive. The FERMT1 gene product and KS protein, kindlin-1, is an epithelial-specific phosphoprotein involved in integrin beta-1 activation, without an obvious link to dermal connective tissue. Here we show how lack of intracellular kindlin-1 in epidermal keratinocytes leads to profound changes in another skin compartment, the dermis. Kindlin-1-deficient keratinocytes respond to cell stress by upregulating the expression of cytokines such as IL-20, IL-24, TGF-β2, IL1F5, PDGFB, and CTGF. These launch-via paracrine communication-an inflammatory response in the dermis, accompanied by the presence of TGF-β, IL-6, and CTGF, activation of fibroblasts and their differentiation to myofibroblasts, which secrete and deposit increased amounts of extracellular matrix proteins. These data are concordant with a model wherein repeated cycles of epidermal cell stress, cytokine secretion, dermal inflammation, and profibrotic processes underlie mucocutaneous fibrosis in KS.