Circulation | Identification of CD47 Target in Doxorubicin-induced Cardiomyopathy and Single-nucleus RNA Sequencing Analysis

This study, for the first time, reveals CD47 overexpression and fibrosis-related cell communication in cardiac tissue of DoxCM patients through single-nucleus RNA sequencing, providing a new target for clinical intervention.

 

Literature Overview

The article titled 'Human single nucleus RNA sequencing identifies CD47 as a therapeutic target for doxorubicin-induced cardiomyopathy', published in the journal Circulation, reviews and summarizes transcriptomic differences between cardiac tissues of DoxCM patients, non-ischemic cardiomyopathy (NICM) patients, and non-heart failure donors, identifying significant upregulation of CD47 in DoxCM patients and validating its role in cardiac fibrosis and dysfunction using a mouse model.

Background Knowledge

Doxorubicin (also known as adriamycin) is a widely used chemotherapeutic agent, but its cardiotoxicity limits clinical application. Doxorubicin-induced cardiomyopathy (DoxCM) is defined as a reduction of left ventricular ejection fraction (LVEF) by ≥10%, accompanied by decreased left ventricular mass, resulting in poor long-term prognosis. Despite extensive animal model studies, the molecular mechanisms underlying DoxCM are not fully understood. Recently, CD47, known as a 'don't eat me' signal molecule, has been found to be overexpressed in tumor cells, where it inhibits macrophage phagocytosis. The research team hypothesizes that CD47 similarly functions as an anti-phagocytic signal in DoxCM, impairing cardiac-resident macrophage function and promoting fibrosis and myocardial atrophy. This study represents the first systematic analysis of CD47 expression and its communication with fibroblasts in human DoxCM cardiac tissue, offering a basis for targeted therapies.

 

 

Research Methods and Experiments

The research team employed single-nucleus RNA sequencing (snRNA-seq) to analyze left ventricular myocardial tissues from non-heart failure donors, DoxCM patients, and NICM patients to identify transcriptomic changes. This was followed by immunohistochemistry, flow cytometry, antibody neutralization, and cell depletion experiments to validate the role of CD47 in a mouse model.

Key Conclusions and Perspectives

• snRNA-seq revealed increased POSTN+ activated fibroblasts, downregulation of phagocytosis-related genes, and significant elevation of CD47 expression in DoxCM patients.
• Both immunohistochemistry and mouse models confirmed co-expression of CD47 and fibroblasts in DoxCM, and CD47 neutralizing antibodies were shown to prevent or treat Dox-induced cardiac dysfunction and fibrosis.
• Depletion of resident macrophages blocked the protective effects of CD47 neutralizing antibodies on the heart, indicating that macrophages play a critical role in DoxCM by promoting fibroblast clearance.
• CD47 was upregulated in both Dox-treated mice and human iPSC-derived fibroblasts, and its expression was partially blocked by an IL-1β neutralizing antibody, suggesting that Doxorubicin induces myocardial injury through the IL-1β-CD47 pathway.
• CD47 neutralizing antibodies effectively restored phagocytosis, reduced fibrosis, and improved cardiac function in the mouse model, identifying CD47 as a promising therapeutic target for DoxCM.

Research Significance and Prospects

This study is the first to identify CD47 as a key molecule in human DoxCM cardiac tissue and elucidate its role in cardiac fibrosis and functional impairment. Future studies should explore the potential of CD47-targeted therapies in protecting the heart in cancer patients and assess their applicability in other chemotherapy-induced cardiomyopathies.

 

 

Conclusion

By utilizing snRNA-seq technology, this study systematically analyzed the transcriptomic features of cardiac tissues in DoxCM patients and identified elevated CD47 expression and accumulation of activated fibroblasts. Using mouse models and cellular experiments, the research team demonstrated that CD47 antibodies can effectively alleviate Doxorubicin-induced cardiac dysfunction and fibrosis, with the protective effects dependent on the integrity of resident macrophages. These findings provide novel insights into the molecular mechanisms of DoxCM and lay the foundation for developing CD47-targeted therapeutic strategies, offering new directions for managing cardiotoxicity associated with cancer therapies.

 

Zhen Guo, Anahita Ataran, Pan Ma, Kory J Lavine, and Ali Javaheri. Human single nucleus RNA sequencing identifies CD47 as a therapeutic target for doxorubicin-induced cardiomyopathy. Circulation.