Salvianolic acid A targets glutamic-oxaloacetic transaminase 2 to ameliorate doxorubicin-induced myocardial oxidative injury by activating malate-aspartate NADH shuttle

Background: Although doxorubicin (DOX) is a highly efficient antineoplastic chemotherapeutic drug, it greatly increases the risk of heart damage. Salvianolic acid A (SAA), a water-soluble active component from traditional Chinese medicine Salvia miltiorrhiza Bunge, is shown to exert various cardioprotective effects. However, the potential of SAA in protecting DOX-induced cardiotoxicity (DIC) and its underlying mechanisms have yet to be elucidated.

Purpose: In the current study, we aimed to identify the targets and investigate the cardioprotective mechanism of SAA improving DIC.

Methods: we established DIC mice to evaluate the cardioprotective effects of SAA by pharmacodynamics, myocardial metabolomic and protomics analysis. Multipe protein-small molecule interaction strategies including surface plasmon resonance, microscale thermophoresis and cellular thermal shift assay, combined with target-depleted cell and animal models were applied for identifying potential targets of SAA. For clinical translation, we also investigated cardioprotective activities of SAA in DOX-treated lewis lung carcinoma-bearing mice.

Results: SAA significantly alleviated cardiomyocyte Apoptosis and oxidative damage, and improved echocardiographic parameters in DIC mice. In addition, myocardium metabolomic and proteomics analysis revealed that SAA preserved hearts by modulating l-Glutamic acid, l-Aspartic acid, citrate and isocitrate and restoring glutamic-oxaloacetic transaminase 2 (GOT2) expression. With the help of multipe protein-small molecule interaction strategies, GOT2 was identified as one of the targets of SAA, and a strong affinity was characterized with a dissociation constant of 1.712μM. SAA ameliorated DOX-induced oxidative damage, mitochondrial respiration suppression, mitochondrial membrane potential loss and NADH levels, which were validated in GOT2 knockdown H9C2 cells. In GOT2 depleted zebrafish, SAA did not display a protective effect against DIC, while in lewis lung carcinoma-bearing mice, SAA not only improved DIC, but also exerted combined anti-tumor effects with DOX.

Conclusion: SAA targets GOT2 to alleviate myocardial oxidative stress by regulating malate-aspartate NADH shuttle, thereby protecting against DIC. Our findings highlighted the therapeutic potential of activating GOT2 in mitigating DIC and the possibility of SAA and DOX-based combination therapy.

Doxorubicin; Glutamic-oxaloacetic transaminase 2; Oxidative Stress; Salvianolic acid A; cardiotoxicity.