GSE162966
IL11 is elevated in systemic sclerosis and IL11-dependent ERK signaling is needed for the profibrotic activity of TGFß in dermal fibroblasts
Objectives: Interleukin 11 (IL11) is highly upregulated in skin and lung fibroblasts from patients with systemic sclerosis (SSc). Here we tested whether IL11 is mechanistically linked with human dermal fibroblast (HDF) activation. Methods: We measured serum IL11 levels in healthy volunteers and patients with early diffuse SSc and manipulated IL11 signalling in HDFs using gain- and loss-of-function approaches. Results: In patients with SSc, serum IL11 levels are elevated as compared to healthy controls. Transforming growth factor beta (TGFß) isoforms 1, 2 or 3 induced IL11 secretion from HDFs, which highly express IL11RA and the gp130 co-receptor, suggestive of an autocrine loop of IL11 activity in HDFs. IL11 consistently and robustly stimulated ERK activation in HDFs and resulted in HDF-to-myofibroblast transformation. IL11 induced STAT phosphorylation to a lesser extent than ERK and only at high IL11 concentrations. IL11-stimulated ERK activation and fibrosis phenotypes were absent in skin fibroblasts from patients with homozygous loss-of-function mutation in IL11RA. Inhibition of IL11 signaling using either a neutralizing antibody against IL11 or siRNA against IL11RA reduced TGFß-induced HDF proliferation, matrix production and cell migration, which was phenocopied by pharmacologic inhibition of ERK activity. Conclusions: These data reveal an important contribution of IL11-related ERK activity for TGFß-stimulated fibrosis phenotypes in HDFs and suggest IL11 as a potential therapeutic target in SSc. Overall design: We sequenced the transcriptome of human dermal fibroblasts (n=4) from a healthy donor.