Phloretin-induced suppression of oxidative and nitrosative stress attenuates doxorubicin-induced cardiotoxicity in rats

Phloretin alleviates doxorubicin-induced cardiotoxicity through regulating Hif3a transcription via targeting transcription factor Fos

BACKGROUND

Doxorubicin (Dox), a chemotherapeutic agent known for its efficacy, has been associated with the development of severe cardiotoxicity, commonly referred to as doxorubicin-induced cardiotoxicity (DIC). The role and mechanism of action of phloretin (Phl) in cardiovascular diseases are well-established; however, its specific function and underlying mechanism in the context of DIC have yet to be fully elucidated.

OBJECTIVE

This research aimed to uncover the protective effect of Phl against DIC in vivo and in vitro, while also providing a comprehensive understanding of the underlying mechanisms involved.

METHODS

DIC cell and murine models were established. The action targets and mechanism of Phl against DIC were comprehensively examined by systematic network pharmacology, molecular docking, transcriptomics technologies, transcription factor (TF) prediction, and experimental validation.

RESULTS

Phl relieved Dox-induced cell apoptosis in vitro and in vivo. Through network pharmacology analysis, a total of 554 co-targeted genes of Phl and Dox were identified. Enrichment analysis revealed several key pathways including the PI3K-Akt signaling pathway, Apoptosis, and the IL-17 signaling pathway. Protein-protein interaction (PPI) analysis identified 24 core co-targeted genes, such as Fos, Jun, Hif1a, which were predicted to bind well to Phl based on molecular docking. Transcriptomics analysis was performed to identify the top 20 differentially expressed genes (DEGs), and 202 transcription factors (TFs) were predicted for these DEGs. Among these TFs, 10 TFs (Fos, Jun, Hif1a, etc.) are also the co-targeted genes, and 3 TFs (Fos, Jun, Hif1a) are also the core co-targeted genes. Further experiments validated the finding that Phl reduced the elevated levels of Hif3a (one of the top 20 DEGs) and Fos (one of Hif3a's predicted TFs) induced by Dox. Moreover, the interaction between Fos protein and the Hif3a promoter was confirmed through luciferase reporter assays.

CONCLUSION

Phl actively targeted and down-regulated the Fos protein to inhibit its binding to the promoter region of Hif3a, thereby providing protection against DIC.

Therapeutic Potential and Pharmaceutical Development of a Multitargeted Flavonoid Phloretin

Phloretin is a flavonoid of the dihydrogen chalcone class, present abundantly in apples and strawberries. The beneficial effects of phloretin are mainly associated with its potent antioxidant properties. Phloretin modulates several signaling pathways and molecular mechanisms to exhibit therapeutic benefits against various diseases including cancers, diabetes, liver injury, kidney injury, encephalomyelitis, ulcerative colitis, asthma, arthritis, and cognitive impairment. It ameliorates the complications associated with diabetes such as cardiomyopathy, hypertension, depression, memory impairment, delayed wound healing, and peripheral neuropathy. It is effective against various microbial infections including Salmonella typhimurium, Listeria monocytogenes, Mycobacterium tuberculosis, Escherichia coli, Candida albicans and methicillin-resistant Staphylococcus aureus. Considering the therapeutic benefits, it generated interest for the pharmaceutical development. However, poor oral bioavailability is the major drawback. Therefore, efforts have been undertaken to enhance its bioavailability by modifying physicochemical properties and molecular structure, and developing nanoformulations. In the present review, we discussed the pharmacological actions, underlying mechanisms and molecular targets of phloretin. Moreover, the review provides insights into physicochemical and pharmacokinetic characteristics, and approaches to promote the pharmaceutical development of phloretin for its therapeutic applications in the future. Although convincing experimental data are reported, human studies are not available. In order to ascertain its safety, further preclinical studies are needed to encourage its pharmaceutical and clinical development.