New insights into the Hippo/YAP pathway in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive disease characterised by an inexorable decline in lung function. The development of IPF involves multiple positive feedback loops; and a strong support role of the Hippo/YAP signalling pathway, which is essential for regulating cell proliferation and organ size, in IPF pathogenesis has been unveiled recently in cell and animal models. YAP/TAZ contributes to both pulmonary fibrosis and alveolar regeneration via the conventional Hippo/YAP signalling pathway, G protein-coupled receptor signalling, and mechanotransduction. Selectively inhibiting YAP/TAZ in lung fibroblasts may inhibit fibroblast proliferation and extracellular matrix deposition, while activating YAP/TAZ in alveolar epithelial cells may promote alveolar regeneration. In this review, we explore, for the first time, the bidirectional and cell-specific regulation of the Hippo/YAP pathway in IPF pathogenesis and discuss recent research progress and future prospects of IPF treatment based on Hippo/YAP signalling, thus providing a basis for the development of new therapeutic strategies to alleviate or even reverse IPF.