Adiponectin suppresses stiffness-dependent, profibrotic activation of lung fibroblasts.

Idiopathic pulmonary fibrosis (IPF) is a progressive, irreversible respiratory disease with limited therapeutic options. A hallmark of IPF is excessive fibroblast activation and extracellular matrix (ECM) deposition. The resulting increase in tissue stiffness amplifies fibroblast activation and drives disease progression. Dampening stiffness-dependent activation of fibroblasts could slow disease progression. We performed an unbiased, next-generation sequencing (NGS) screen to identify signaling pathways involved in stiffness-dependent lung fibroblast activation. Adipocytokine signaling was downregulated in primary lung fibroblasts (PFs) cultured on stiff matrices. Re-activating adipocytokine signaling with adiponectin suppressed stiffness-dependent activation of human PFs. Adiponectin signaling depended on CDH13 expression and p38 mitogen-activated protein kinase gamma (p38MAPKγ) activation. CDH13 expression and p38MAPKγ activation were strongly reduced in lungs from IPF donors. Our data suggest that adiponectin-signaling via CDH13 and p38MAPKγ activation suppresses profibrotic activation of fibroblasts in the lung. Targeting of the adiponectin signaling cascade may provide therapeutic benefits in IPF. A hallmark of idiopathic pulmonary fibrosis (IPF) is excessive fibroblast activation and extracellular matrix (ECM) deposition. The resulting increase in tissue stiffness amplifies fibroblast activation and drives disease progression. Dampening stiffness-dependent activation of fibroblasts could slow disease progression. We found that activation of the adipocytokine signaling pathway halts and reverses stiffness-induced, profibrotic fibroblast activation. Specific targeting of this signaling cascade may therefore provide therapeutic benefits in IPF.