Single-Cell Analyses Reveal IKKα Regulates the Interaction Between Macrophages and T Cells in the Doxorubicin-Induced Cardiomyopathy

Doxorubicin (DOX) is a chemotherapeutic agent used to treat solid tumors and hematologic malignancies, though DOX-induced cardiomyopathy poses a risk of severe cardiac impairment and poor prognosis. Immune cells have been increasingly implicated in cardiovascular inflammation, with overproduction of inflammatory cytokines and macrophage accumulation. However, its molecular mechanism remains unclear and needs to be further investigated. This study investigated the involvement of IKKα in regulating cardiac function in response to early-stage DOX stimulation. Results indicated that IKKα^Lyz2-Cre mice were more susceptible to DOX-induced cardiac injury than IKKα^flox/flox mice, showing reduced heart function, extensive cardiac fibrosis, and elevated inflammatory markers. Single-cell transcriptomic analysis revealed cellular heterogeneity in DOX-induced cardiomyopathy tissue between IKKα^flox/flox and IKKα^Lyz2-Cre mice, identifying 11 cell types, 8 of which were immune cells. Bar plots and cell density analysis showed a higher proportion of T cells in IKKα^flox/floxmice, while IKKα^Lyz2-Cre mice had increased monocytes and macrophages. Notably, IKKα deletion promoted a shift in macrophage polarization from Fcna⁺ M2 to Jaml⁺ M1 and impaired T cell activation and differentiation. Additionally, IKKα played a critical role in mediating macrophage-T cell interactions. Loss of macrophage IKKα activated T cells through Jaml⁺ M1 macrophage, and activated T cells subsequently enhanced M1 macrophage activation via IFN-γ and IL-6. These findings highlight the potential of targeting immune cell interactions as a therapeutic strategy.