<i> CX3CR1 ⁺ </i> macrophages aggravate doxorubicin-induced cardiomyopathy by impairing cardiac mitophagy via the CSF1R-PARP1-IL1B axis

Doxorubicin is a widely used chemotherapeutic agent, but its clinical application is hindered by severe cardiotoxicity. Among immune cells, Cx3cr1+ macrophages have emerged as key regulators of cardiovascular disease, with their development and maturation tightly controlled by CSF1R (colony stimulating factor 1 receptor). Using multi-omics sequencing, we observed a marked expansion of Cx3cr1+ macrophages in doxorubicin-induced cardiomyopathy, yet their precise functional role in this pathological process has remained elusive. This study employed various genetically modified mouse models, including cell depletion models, lineage tracing models, and conditional gene knockout models targeting Cx3cr1+ macrophages, alongside transcriptomic sequencing, proteomic profiling, and multi-level in vivo and in vitro experiments to elucidate the role and mechanisms of Cx3cr1+ macrophages and their receptor CSF1R in doxorubicin-induced cardiac injury. We found that Cx3cr1+ macrophages are significantly enriched in hearts affected by doxorubicin-induced cardiomyopathy, and their depletion notably improves cardiac function. Further investigation revealed that in these macrophages, CSF1R competitively binds to the E3 ubiquitin ligase NEDD4, thereby inhibiting the ubiquitination and degradation of PARP1. This process promotes inflammasome activation and pyroptosis, driving massive IL1B secretion. IL1B directly suppresses cardiomyocyte mitophagy, disrupts energy metabolic homeostasis, and ultimately leads to cardiac dysfunction. Notably, the use of the CSF1R inhibitor PLX3397 or an IL1B-neutralizing antibody effectively halted these pathological processes and significantly improved cardiac function. In summary, this study unveils a novel mechanism through which Cx3cr1+ macrophages regulate cardiomyocyte function via the CSF1R-PARP1-IL1B-mitophagy signaling axis, providing a new theoretical foundation and intervention strategy for doxorubicin-induced cardiomyopathy targeted therapy.Abbreviations: BMDM: bone marrow-derived macrophages; CKMB: creatine kinase MB isoenzyme; CSF1R: colony stimulating factor 1 receptor; csf1r-cKO: csf1r conditional knockout; DIC: doxorubicin-induced cardiomyopathy; DOX: doxorubicin; HE: hematoxylin and eosin; HW:TL: heart weight:tibial length; LDH: lactate dehydrogenase; MAP1LC3/LC3: microtuble-associated protein 1 light chain 3; NPPA: natriuretic peptide type A; PI: propidium iodide; PYCARD/ASC: PYD and CARD domain containing; TNNT2/cTnT: troponin T2, cardiac; WGA: wheat germ agglutinin.