Huanglian-ejiao decoction ameliorates doxorubicin-induced cardiomyocyte apoptosis and autophagic flux dysregulation by up-regulating ubiquilin1

Ethnopharmacological relevance: Huanglian-Ejiao decoction (HLEJD) is formulated based on the traditional Chinese medicine (TCM) theory of "coordination between the heart and the kidney" with the treatment principle of "nourishing kidney yin and clearing the heart yang." It serves as a representative prescription for treating symptoms associated with "disharmony between the heart and the kidney", such as palpitations, restlessness, insomnia, tinnitus, low back/knee and soreness and weakness. Clinical studies have demonstrated that HLEJD can significantly alleviate doxorubicin (DOX)-induced cardiotoxicity (DIC). However, the underlying mechanisms remain to be elucidated.

Aim of the study: To investigate the cardioprotective effects of HLEJD against DIC in vivo and in vitro, and to elucidate the underlying cellular alteration involved in DOX-induced cardiomyocyte Apoptosis and impaired autophagic flux.

Materials and methods: DIC mouse models were established in C57BL/6 mice with DOX. HLEJD was administered via gavage. Cardiac function was assessed using echocardiography, and serum biochemical parameters indicative of myocardial injury were measured by ELISA. Histopathological evaluations, including H&E, Masson, WGA, and TUNEL staining, were performed to examine cardiomyocyte morphology, fibrosis, cellular dimensions, and Apoptosis. Ultrastructural changes in cardiac tissue were analyzed using transmission electron microscopy. The effects of HLEJD on DOX-triggered cardiomyocyte Apoptosis and autophagic flux dysregulation were investigated using flow cytometry, RT-qPCR, western blotting, lysotracker staining and GFP-RFP-LC3 plasmid transfection. Additionally, proteomic Sequencing, siRNA-mediated gene silencing and plasmid transfection-mediated gene overexpression were used to explore the molecular mechanisms involved.

Results: We demonstrated that HLEJD significantly attenuates DOX-induced myocardial injury by mitigating Apoptosis and autophagic flux dysregulation in cardiomyocytes both in vivo and in vitro. Moreover, HLEJD mediated cardioprotection through the upregulation of ubiquilin1 (UBQLN1) expression. Additionally, UBQLN1 depletion exacerbated DOX-induced Apoptosis and autophagic flux inhibition in cardiomyocytes.

Conclusions: Our findings confirmed the preclinical rationale for the cardio-protective effects of HLEJD, validated that UBQLN1 protected against autophagic flux disruption and Apoptosis in DIC, and highlighted the potential of HLEJD for natural therapeutic development. However, the bioactive components of HLEJD need clarification.

Cardiotoxicity; Doxorubicin; Huanglian-Ejiao decoction; ubiquilin-1.