Investigating podophyllotoxin-induced cardiotoxicity in rats by Toxicological Evidence Chain (TEC): Focus on the Akt1/Srebp-1c/PUFAs axis

Podophyllotoxin, an efficacious constituent derived from the traditional Chinese medicine Dysosma versipellis, exhibits antitumor properties; however, its toxicity limits clinical application. This study, based on the Toxicological Evidence Chain (TEC), employs metabolomics and lipidomics approaches to investigate the mechanisms underlying its cardiotoxicity. Injury phenotype evidence (IPE) was obtained through observation of the rats’ external phenotypes, including coat condition, body weight, fecal characteristics, mental status, and presence of bleeding. Cardiac enzyme levels, blood lipid profiles, and histopathological examinations of heart tissues were assessed as evidence of adverse outcomes (AOE). To obtain evidence of toxic events, an integrated analysis of metabolomics, lipidomics, network toxicology was conducted on rat serum and heart tissues and molecular biology experiments in vitro, revealing the mechanism of PPT-induced cardiotoxicity. The results indicated that PPT induced pathological changes in rats, including weight loss, dull and brittle fur, and lethargy, along with nasal bleeding and diarrhea. The levels of AST, TC, and LDL-C were significantly elevated, while TG and HDL-C showed significant decreases. Integrated metabolomics analysis revealed 21 significantly altered differential metabolites demonstrating concordant directional changes across both serum and cardiac tissues. Complementary lipidomics profiling identified 31 dysregulated lipid species with coordinated variations in both biological matrices. These perturbed metabolites were principally associated with the core metabolic pathways: synthesis and metabolism of unsaturated fatty acid lipids. Network toxicology predictions identified Akt1, Egfr, Mtor, and Nos3 as potential critical molecular targets of PPT. In vitro experiments show that targeting the Akt1/Rebp-1c axis with PPT induces oxidative stress and cell death in cardiomyocytes, which can be mitigated by unsaturated fatty acids. This discovery offers a new approach for using PPT in clinical settings, potentially reducing its cardiotoxicity by administering unsaturated fatty acid simultaneously.