IL-11 is a therapeutic target in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease where invasive pulmonary myofibroblasts secrete collagen and destroy lung integrity. Here we show that IL-11 is upregulated in the lung of IPF patients, associated with disease severity and is secreted from IPF fibroblasts. In vitro, IL-11 stimulates lung fibroblasts to become invasive, ACTA2+ve, collagen secreting myofibroblasts, in an ERK-dependent fashion. In mice, fibroblast-specific transgenic expression or administration of Il-11 drives lung fibroblast-to-myofibroblast transformation and causes lung fibrosis. Il11ra1 deleted mice, whose lung fibroblasts are unresponsive to pro-fibrotic stimulation, are protected from fibrosis in the bleomycin mouse model of pulmonary fibrosis. We generated an IL-11 neutralising antibody that blocks lung fibroblast activation downstream of multiple stimuli and reverses myofibroblast activation. In therapeutic studies, anti-IL-11 treatment both prevented and reversed lung fibrosis, which was accompanied by diminished Erk activation. These data prioritise IL-11 as a drug target for lung fibrosis and IPF. For human in vitro samples, 3 commercial and 2 patient-derived normal lung fibroblasts were stimulated with either TGFB or IL11 and compared with baseline accounting for the sample effect (matched design) and the source effect. Mouse in vitro samples were also treated similarly and were analyzed using a matched design. Mouse in vivo samples have 4 replicates per treatment group.