1. Syndecan-1 shedding by meprin β impairs keratinocyte adhesion and differentiation in hyperkeratosis
- Author
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Anna Otte, Erwin F. Wagner, Christoph Becker-Pauly, Franka Scharfenberg, Marion Mengel, Sascha Rahn, F. Thomas Wunderlich, Florian Peters, Ronald Naumann, Andreas Tholey, Tomas Koudelka, and Michael Haase
- Subjects
Keratinocytes ,Genetically modified mouse ,Metalloproteinase ,Epidermis (botany) ,Chemistry ,Cell Membrane ,Proteolytic enzymes ,Metalloendopeptidases ,Transcription factor complex ,Cell Differentiation ,Syndecan 1 ,Cell biology ,Mice ,medicine.anatomical_structure ,Downregulation and upregulation ,medicine ,Animals ,Syndecan-1 ,Keratinocyte ,Molecular Biology - Abstract
Dysregulation of proteolytic enzymes has huge impact on epidermal homeostasis, which can result in severe pathological conditions such as fibrosis or Netherton syndrome. The metalloprotease meprin β was found to be upregulated in hyperproliferative skin diseases. AP-1 transcription factor complex has been reported to induce Mep1b expression. Since AP-1 and its subunit fos-related antigen 2 (fra-2) are associated with the onset and progression of psoriasis, we wanted to investigate if this could partially be attributed to increased meprin β activity. Here, we demonstrate that fra-2 transgenic mice show increased meprin β expression and proteolytic activity in the epidermis. To avoid influence by other fra-2 regulated genes, we additionally generated a mouse model that enabled tamoxifen-inducible expression of meprin β under the Krt5-promotor to mimic the pathological condition. Interestingly, induced meprin β expression in the epidermis resulted in hyperkeratosis, hair loss and mottled pigmentation of the skin. Employing N-terminomics revealed syndecan-1 as a substrate of meprin β in skin. Shedding of syndecan-1 at the cell surface caused delayed calcium-induced differentiation and impaired adhesion of keratinocytes, which was blocked by the meprin β inhibitor fetuin-B.
- Published
- 2021