Interleukin-4 Receptor ? Signaling in Myeloid Cells Controls Collagen Fibril Assembly in Skin Repair.

ABSTRACT: Activation of the immune response during injury is a critical early event that determines whether the outcome of tissue restoration is regeneration or replacement of the damaged tissue with a scar. The mechanisms by which immune signals control these fundamentally different regenerative pathways are largely unknown. We have demonstrated that, during skin repair in mice, interleukin-4 receptor ? (IL-4R?)-dependent macrophage activation controlled collagen fibril assembly and that this process was important for effective repair while having adverse pro-fibrotic effects. We identified Relm-? as one important player in the pathway from IL-4R? signaling in macrophages to the induction of lysyl hydroxylase 2 (LH2), an enzyme that directs persistent pro-fibrotic collagen cross-links, in fibroblasts. Notably, Relm-? induced LH2 in human fibroblasts, and expression of both factors was increased in lipodermatosclerosis, a condition of excessive human skin fibrosis. Collectively, our findings provide mechanistic insights into the link between type 2 immunity and initiation of pro-fibrotic pathways.

SUBMITTER: Knipper JA 

PROVIDER: S-EPMC4681399 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature