Single cell and spatial sequencing define processes by which keratinocytes and fibroblasts amplify inflammatory responses in psoriasis

F Ma, O Plazyo, AC Billi, LC Tsoi, X Xing… - Nature …, 2023 - nature.com
F Ma, O Plazyo, AC Billi, LC Tsoi, X Xing, R Wasikowski, M Gharaee-Kermani, G Hile…
Nature communications, 2023nature.com
The immunopathogenesis of psoriasis, a common chronic inflammatory disease of the skin,
is incompletely understood. Here we demonstrate, using a combination of single cell and
spatial RNA sequencing, IL-36 dependent amplification of IL-17A and TNF inflammatory
responses in the absence of neutrophil proteases, which primarily occur within the
supraspinous layer of the psoriatic epidermis. We further show that a subset of SFRP2+
fibroblasts in psoriasis contribute to amplification of the immune network through transition to …
Abstract
The immunopathogenesis of psoriasis, a common chronic inflammatory disease of the skin, is incompletely understood. Here we demonstrate, using a combination of single cell and spatial RNA sequencing, IL-36 dependent amplification of IL-17A and TNF inflammatory responses in the absence of neutrophil proteases, which primarily occur within the supraspinous layer of the psoriatic epidermis. We further show that a subset of SFRP2+ fibroblasts in psoriasis contribute to amplification of the immune network through transition to a pro-inflammatory state. The SFRP2+ fibroblast communication network involves production of CCL13, CCL19 and CXCL12, connected by ligand-receptor interactions to other spatially proximate cell types: CCR2+ myeloid cells, CCR7+LAMP3+ dendritic cells, and CXCR4 expressed on both CD8+ Tc17 cells and keratinocytes, respectively. The SFRP2+ fibroblasts also express cathepsin S, further amplifying inflammatory responses by activating IL-36G in keratinocytes. These data provide an in-depth view of psoriasis pathogenesis, which expands our understanding of the critical cellular participants to include inflammatory fibroblasts and their cellular interactions.
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