2023, Vol. 27 ›› Issue (8): 1264-1271

YAP/TAZ, a core factor of the Hippo signaling pathway, is involved in bone formation

Yang Zhishan1, 2, Tang Zhenglong1, 2   

Abstract: BACKGROUND: As the role of mechanical signalling in the bone has been increasingly studied, YAP/TAZ as a mechanosensitive factor has gradually attracted public attention. Existing studies have found that YAP/TAZ may be involved as an important mediator in the process of bone formation, but the mechanism is not yet clear.
OBJECTIVE: To summarize the latest research on the effects of YAP/TAZ in bone formation.
METHODS: The first author used “Hippo pathway, YAP/TAZ, bone, osteogenesis” as English and Chinese search terms to search in the PubMed and CNKI databases for relevant articles published from 2016 to March 2022. After screening and summarizing, 56 relevant articles were finally included for review.
RESULTS AND CONCLUSION: YAP/TAZ, as the core factor of the Hippo pathway, has special features in its functional regulation. In addition to regulating its activity at the molecular level, changes in the cellular microenvironment, such as cell density, cell shape and extracellular matrix stiffness, can also contribute to its altered activity and thus YAP/TAZ can play different functional roles. YAP/TAZ is involved in osteogenic signaling and its regulation is also influenced by the cellular microenvironment. Overexpression or silencing of YAP/TAZ in cells can contribute to or inhibit osteogenic signaling, thereby altering the outcome of cell differentiation. YAP/TAZ is involved in the osteogenesis process of bone tissue cells and has different functions for different types of bone tissue cells. However, different methods for overexpressing or silencing YAP/TAZ and different types of cell species selected for observation make it difficult to quantify the results uniformly. In animal experiments, it has been shown that YAP/TAZ is essential for the morphological development of normal bones and maxillofacial regions, and has different functions at different stages of osteogenic differentiation. However, there is no uniformity in the knockout of YAP/TAZ conditional genes in experimental animals and the timing of observations is inconsistent, which make it difficult to compare experimental results with each other. To conclude, YAP/TAZ has an important role in bone formation, but its mechanism still needs to be further investigated. We expect that more scholars will explore its mechanism in depth and use its properties to cure bone diseases.
Key words: YAP/TAZ, transforming growth factor β, bone morphogenetic protein 2, Smads family, osteogenic differentiation, osteoclast, macrophage, bone morphology, maxillofacial deformity