TNFAIP3 Modulates Macrophage Polarization Post-Myocardial Infarction through Its Restraint on the JAK2-STAT1 Signaling Axis

Macrophages are vital for heart repair after myocardial infarction (MI), a process that requires their transition from M1 to M2 type. However, the underlying mechanisms are unclear. This study aimed to explore the role of TNFAIP3 in regulating macrophage polarization post-MI.mRNA and protein levels of target genes were measured via qPCR and ELISA. Western blot and immunofluorescence were used to analyze protein expression and cell proportions. Primary human CD14+ monocytes were polarized into M1 (with LPS/IFNγ) or M2 (with IL-4) macrophages. TNFAIP3 was knocked down or overexpressed in vitro using shRNA or adenovirus. For in vivo studies, TNFAIP3 was overexpressed in mice via AAV, and myocardial infarction was induced by permanent left anterior descending coronary artery ligation.TNFAIP3 mRNA was elevated in PBMCs from AMI patients versus controls. Although both M1 (TNF-α, IL-6) and M2 (IL-10, TGF-β) serum cytokines increased in patients, TNFAIP3 was negatively correlated with M1 markers. Functionally, TNFAIP3 knockdown exacerbated LPS/IFNγ-induced M1 polarization, increasing TNF-α/IL-6 mRNA expression and NOS2-positive cells, while its overexpression suppressed these effects. In contrast, neither intervention altered IL-4-induced M2 polarization. Mechanistically, TNFAIP3 deficiency enhanced JAK2/STAT1 phosphorylation to promote M1 polarization, which was reversed by pharmacological inhibition and genetic knockdown of JAK2/STAT1. In vivo, systemic TNFAIP3 overexpression attenuated MI-induced JAK2/STAT1 activation, TNF-α/IL-6 mRNA upregulation, and NOS2-positive macrophage infiltration, without affecting IL-10/TGF-β mRNA and ARG1-positive cells.TNFAIP3 functions as an important modulator of post-MI inflammation by limiting M1 macrophage polarization through JAK2/STAT1 suppression.