Benzophenone-2 Disrupts Craniofacial Cartilage Development via esr2a-Dependent Inhibition of Endothelin Signaling in Zebrafish Larvae

Epidemiological evidence has linked early-life exposure to estrogenic endocrine-disrupting chemicals (e-EDCs) to craniofacial malformations. Benzophenone-2 (BP2), a representative e-EDC, is frequently detected in environmental media and biological samples. However, the developmental effects of BP2 on craniofacial chondrogenesis and the underlying mechanisms remain unclear. Here, we demonstrate that early exposure to environmentally relevant concentrations of BP2 induces orofacial cleft-like craniofacial defects in zebrafish larvae, characterized by jaw flattening and anterior neurocranium shortening. Using Tg (sox10: EGFP) zebrafish, we traced these abnormalities to disrupted cranial neural crest cell (CNCC) development. Morpholino knockdown and genetic knockout further identified estrogen receptor signaling as a key mediator of BP2-induced craniofacial toxicity, with esr2a exerting the predominant effect. Mechanistically, esr2a activation suppresses endothelin signaling, thereby disrupting CNCC-dependent craniofacial development, and pharmacological activation of the endothelin pathway markedly alleviates these defects. Together, these findings identify an esr2a-endothelin signaling axis underlying BP2-induced disruption of CNCC-derived craniofacial cartilage development. This work highlights craniofacial chondrogenesis as a sensitive developmental target of e-EDCs exposure, and provides new mechanistic insight for environmental health risk assessment.