Crosstalk between YAP/TAZ and ERα in mechanical and hormonal signaling in the skeletal system

Bone remodeling represents a dynamic equilibrium orchestrated by mechanobiological and endocrine signals, with YAP/TAZ and ERα emerging as pivotal regulators of skeletal adaptation. YAP/TAZ functions as the central mechanotransduction hub of the Hippo pathway, converting biomechanical cues, including microenvironment matrix stiffness and shear stress, into osteogenic transcriptional programs. Concurrently, ERα integrates both mechanical stimuli and estradiol (E2) signaling to coordinate osteoblast-osteoclast coupling through the transcriptional regulation of RUNX2 activity and RANKL suppression. Although increasing evidence suggests that these two systems might engage in functional crosstalk, there is still no consensus on this issue. This review synthesizes the current understanding of YAP/TAZ-ERα interactions across three dimensions: (1) mechanohormonal integration in skeletal remodeling, (2) context-dependent reciprocity in breast carcinogenesis, and (3) tissue-specific regulatory paradigms in extra-skeletal systems. Key findings reveal that YAP/TAZ and ERα exhibit both synergistic cooperation (enhanced osteogenic differentiation via promoter co-occupancy) and pathway antagonism (competitive TEAD binding), with their interaction dynamics being critically shaped by the cellular microenvironmental context. Notably, mechanical potentiation of ERα transcriptional activity requires YAP/TAZ co-activation in bone mesenchymal stem cells, whereas estrogen signaling modulates YAP mechanosensitivity through cytoskeletal remodeling. These mechanistic insights indicate that the YAP/TAZ-ERα axis is a promising therapeutic target for osteoporotic bone loss, particularly in alveolar bone preservation. By bridging endocrine and mechanobiological perspectives, this work provides a conceptual framework for developing combinatorial therapies that simultaneously address hormonal imbalance and mechanical insufficiency in skeletal pathologies.