Long Noncoding RNA PCALRx Interacts with Pyruvate Carboxylase to Drive Multi‐Organ Developmental Toxicity in Zebrafish Embryos Exposed to Amoxicillin

Amoxicillin is widely used in human and veterinary medicine and is increasingly detected in aquatic systems, raising concerns regarding its potential adverse effects on sensitive developmental stages. Here, a zebrafish embryonic amoxicillin exposure (EAE) model was used to quantify dose- and time-dependent developmental outcomes and to elucidate underlying metabolic-epigenetic mechanisms. EAE induced dose- and time-dependent increases in mortality and malformation rates, and significantly impaired differentiation of liver, interrenal gland, heart and brain, accompanied by mitochondrial structural damage and reduction in ATP levels. Multi-omics integration identified a previously uncharacterized long noncoding RNA, PCALRx, which was associated with pyruvate carboxylase (PC) and negatively regulated PC protein stability. PCALRx promoted ubiquitination-mediated degradation of PC, resulting in impaired mitochondrial metabolic function and subsequent multi-organ differentiation defects. Knockdown of PCALRx mitigated mitochondrial dysfunction and improved EAE-induced developmental defects. Finally, a drug-repurposing strategy nominated thiamine (vitamin B1) as a metabolic modulator capable of mitigating EAE-induced developmental changes in zebrafish larvae. This protective effect was further validated in a mouse model of prenatal amoxicillin exposure. Together, these findings reveal an lncRNA-mediated regulatory mechanism involving PC ubiquitination and mitochondrial metabolic disruption in amoxicillin-associated developmental toxicity and provide a potential intervention strategy relevant to environmental amoxicillin exposure.