Eupalinolide A attenuates trauma-induced heterotopic ossification of tendon in mice by promoting YAP degradation through TOLLIP-mediated selective autophagy

Background: Inhibiting the aberrant osteogenic differentiation of tendon-derived stem cells (TDSCs) is an effective strategy for treating traumatic heterotopic ossification (HO) in tendons. Purpose: This study aimed to investigate whether eupalinolide A (EA) could prevent tendon HO progression by suppressing the osteogenic differentiation of TDSCs. Methods: The effects of EA on osteogenic differentiation and key signaling pathways in TDSCs were examined in vitro to assess its therapeutic potential and elucidate the underlying molecular mechanisms. Furthermore, the therapeutic efficacy of EA was evaluated in a mouse model of trauma-induced tendon HO via local injection therapy. Results: EA significantly inhibited the osteogenic differentiation of TDSCs by targeting YAP in vitro. Specifically, EA facilitated the recruitment of E3 ubiquitin ligase HECW1, which mediated K27-linked polyubiquitination of YAP, leading to its degradation via the TOLLIP-mediated selective autophagy pathway. In vivo, EA mitigated trauma-induced tendon HO by inhibiting the YAP pathway.