Doxorubicin is a chemotherapeutic drug utilized for solid tumors and hematologic malignancies, but its clinical application is hampered by life-threatening cardiotoxicity, including cardiac dilation and heart failure. Mitophagy, a cargo-specific form of autophagy, is specifically used to eliminate damaged mitochondria in autophagosomes through hydrolytic degradation following fusion with lysosomes. Recent advances have unveiled a major role for defective mitophagy in the etiology of DOX-induced cardiotoxicity. Moreover, specific interventions targeting this mechanism to preserve mitochondrial function have emerged as potential therapeutic strategies to attenuate DOX-induced cardiotoxicity. However, clinical translation is challenging because of the unclear mechanisms of action and the potential for pharmacological adverse effects. This review aims to offer fresh perspectives on the role of mitophagy in the development of DOX-induced cardiotoxicity and investigate potential therapeutic strategies that focus on this mechanism to improve clinical management.
27 November 2024 in Journal of the American Heart Association
Background: Inflammation and metabolic disturbances are key culprits in the pathogenesis of obesity‐associated cardiomyopathy. The NLRP3 (nucleotide‐binding oligomerization domain‐like receptor 3) inflammasome mediates the release of the proinflammatory cytokines IL‐1β (interleukin‐1β) and IL‐18 by activating caspase‐1, which is strongly implicated in metabolic disturbances. We here sought to determine whether NLRP3 inflammasome inhibition could ameliorate obesity cardiomyopathy and if so, to further explore its underlying mechanisms. Methods and Results: Male mice were fed a high‐fat diet for 24 weeks to induce obesity cardiomyopathy. MCC950 was used to inhibit NLRP3 inflammasome activation. Recombinant adeno‐associated virus serotype 9 encoding TXNIP (thioredoxin‐interacting protein) under cTnT (cardiac troponin T) promoter and the mitochondrial‐targeted antioxidant MitoTEMPO were injected into obese mice to investigate the specific mechanism. To mimic obesity cardiomyopathy in vitro, neonatal rat ventricular myocytes transfected with the small interfering RNA against TXNIP were incubated with 400 μmol palmitic acid for 24 hours. NLRP3 inflammasome was significantly increased in obese hearts. NLRP3 inflammasome inhibition by NLRP3 deletion or MCC950 prevented obesity‐induced cardiac systolic and diastolic dysfunction, myocardial hypertrophy and fibrosis, and excessive lipid accumulation in male mice. Conversely, TXNIP overexpression worsened obesity‐associated cardiomyopathy. Similarly, MCC950 treatment or TXNIP knockdown reduced palmitic acid‐induced NLRP3 inflammasome activation and lipid storage. Mechanistically, abnormal NF‐κB (nuclear factor kappa B) pathway activation, increased mitochondrial reactive oxygen species, and elevated TXNIP levels led to excessive NLRP3 inflammasome activation. Conclusions: Our study confirms that aberrant NLRP3 inflammasome activation in cardiomyocytes worsens obesity‐associated cardiomyopathy and implicates inhibition of NLRP3 inflammasome as a potent therapeutic approach for obesity cardiomyopathy.
Despite the clinical efficacy of doxorubicin (DOX), effective strategies to prevent its cardiotoxicity are still lacking. Finerenone, a nonsteroidal mineralocorticoid receptor antagonist (MRA), has demonstrated cardioprotective properties; however, its role and mechanism in DOX-induced cardiotoxicity (DIC) remain unclear. In this study, Finerenone treatment was found to significantly alleviate DOX-induced cardiac dysfunction and pathological remodeling in both mouse models and cultured cells. Mechanistically, molecular docking suggests that Finerenone may directly bind to Latent Transforming Growth Factor Beta Binding Protein 2 (LTBP2), a key regulator of TGF-β bioavailability. This potential binding could inhibit the LTBP2–TGF-β axis, thereby suppressing DOX-induced activation and subsequent Smad3 phosphorylation. The importance of this pathway was supported by the similar anti-fibrotic effects observed with the TGF-β inhibitor LY2109761. However, our findings on the direct binding of Finerenone to LTBP2 are preliminary and require further validation through additional experimental approaches. These results identify LTBP2 as a novel direct target of Finerenone and reveal an additional mechanism underlying its cardioprotective action, suggesting its potential repurposing for the prevention of DIC.