Psoriasis: a microbiome-driven disease?

Grantee: Patrick Zeeuwen, Radboud University Medical Center, Nijmegen, The Netherlands

Grant: 2,545,944 DKK

Psoriasis is highly prevalent and has a significant medical and socio-economic impact.

The prevailing dogma has been that abnormalities of the adaptive immune system were primary, but genetic studies have highlighted the importance of local skin-specific factors. We and others have identified epidermis-specific innate immunity genes, like beta-defensins and Late Cornified Envelope (LCE) genes, to be associated with disease development.

We recently made two exciting observations. First, deletion of LCE3B and LCE3C does not merely imply the loss of two genes but has a genomic effect that leads to a strong induction of the flanking LCE3A gene. Secondly, we found that LCE proteins, and LCE3A in particular, have broad-spectrum antimicrobial activity. We hypothesize that the LCE3B/C-del status affects the cutaneous host defense repertoire thereby shaping the skin microbiome. We aim to investigate the biology of LCE genes and to translate these findings to our understanding of psoriasis pathogenesis.

Key objectives are to:

  1. assess the antimicrobial activity and specificity of all LCEs and their synergy with other antimicrobial proteins. This will be investigated by metagenomic approaches and classical in vitro microbiological assays, using recombinant and synthetic LCE proteins and peptides derived thereof
  2. investigate LCE3B/C-del in isogenic 3D-skin equivalents in vitro generated from the immortalized human keratinocyte N/TERT cell line. Deletions of other LCE genes or their regulatory sequences will be made using CRISPR/Cas9 technology. Effects on epidermal biology relevant to psoriasis will be studied and include antimicrobial host defense, innate immune response and skin barrier function