Ablation of LRP6 in alpha-smooth muscle actin-expressing cells abrogates lung inflammation and fibrosis upon bleomycin-induced lung injury.

Abstract

Tissue fibrosis is a progressive pathological process with excessive deposition of extracellular matrix proteins (ECM). Myofibroblasts, identified by alpha-smooth muscle actin (αSMA) expression, play an important role in tissue fibrosis by producing ECM. Here, we found that the Wnt antagonist Dickkopf1 (DKK1) induced gene expressions associated with inflammation and fibrosis in lung fibroblasts. We demonstrated that genetic deletion of LRP6, a receptor for Wnt ligands and DKK1, in αSMA-expressing cells using Acta2-cre Lrp6^fl/fl (Lrp6^AKO) mice abrogated the bleomycin (BLM)-induced lung inflammation and fibrosis phenotype, suggesting an important role for LRP6 in modulating inflammation and fibrotic processes in the lung. Our results highlight the crucial role of LRP6 in fibroblasts in regulating inflammation and fibrosis upon BLM-induced lung injury.