Macrophage Histone Lactylation Drives Inflammatory Activation in Heart Failure via the IFIT3/JNK Signaling Axis

Aims: Heart failure (HF) is characterized by persistent inflammation, although its underlying immunometabolic regulatory mechanisms remain unclear. We investigated whether the interferon-induced protein IFIT3 drives inflammatory activation in cardiac macrophages and defined its downstream signaling and epigenetic regulatory mechanisms. Methods: We performed integrated bioinformatics analyses of single-cell RNA sequencing data from human failing hearts (GEO: GSE145154) and identified IFIT3 as a macrophage-specific hub gene. In vivo experiments showed increased IFIT3 protein expression in myocardial tissue from transverse aortic constriction (TAC), colocalizing with macrophage markers. Echocardiography, histology, and molecular assays evaluated cardiac function and pathological alterations in pressure-overload HF mice. Using macrophage-specific IFIT3 knockout mice, siRNA-mediated knockdown in RAW264.7 cells, and treatments with a JNK pathway agonist (anisomycin) and exogenous sodium lactate, we validated IFIT3 ’s role in vivo and in vitro , and investigated its mechanism in regulating macrophage polarization via the JNK/histone lactylation axis. Results: Single-cell transcriptomic analysis revealed that IFIT3 is significantly upregulated in macrophages from failing human hearts and functions as a core hub gene. In TAC-induced heart failure in mice, myocardial IFIT3 protein expression increased and colocalized with macrophage markers. Macrophage-specific IFIT3 knockout significantly improved cardiac function in TAC mice, attenuated myocardial hypertrophy and fibrosis, and reduced systemic and local pro-inflammatory cytokine levels. IFIT3 knockdown suppressed inflammatory responses in macrophages, accompanied by decreased JNK phosphorylation (p-JNK) and histone H3K9 lactylation (H3K9la). JNK pathway activation reversed the inhibition of H3K9la and inflammatory cytokine secretion caused by IFIT3 knockdown, whereas exogenous sodium lactate supplementation directly restored H3K9la modification and partially rescued cytokine production. Conclusion: Macrophage-derived IFIT3 is a key driver of inflammatory response in heart failure. Mechanistically, IFIT3 activates the JNK signaling pathway, promoting histone H3K9 lactylation and upregulating the transcription and secretion of pro-inflammatory cytokines. These findings establish the " IFIT3 /JNK/histone lactylation" axis—a pathogenic link between immune signaling and metabolic epigenetics. This study provides a new potential target and theoretical basis for precision immunotherapy in heart failure.