DNA-PK-mediated phosphorylation of STAT6 establishes a non-canonical type 2 immunity axis to prevent macrophage senescence

Macrophage senescence drives inflammaging, a chronic, age-related inflammation. To date, the protective mechanisms against inflammaging are poorly defined. Here, we identify DNA-PK-mediated phosphorylation of murine STAT6 at serine 807 (Ser807) as a crucial post-translational modification for preventing macrophage senescence. Ser807 phosphorylation blocks STAT6 ubiquitination-mediated degradation and promotes STAT6 partnering with PU.1 to activate DNA repair genes. Macrophages lacking Ser807 phosphorylation exhibit DNA repair defects, undergo senescence, and fuel inflammaging. In vivo, the phosphor-null STAT6 mutant (STAT6(S807A)) accelerates macrophage senescence, tissue fibrosis, and systemic aging. Adoptive transfer of phosphomimetic STAT6(S807E)-expressing macrophages rescues accelerated aging. Importantly, phosphorylation of human STAT6 at the homologous residue (Ser817) is significantly reduced in the lungs of patients with chronic obstructive pulmonary disease (COPD), correlating with increased DNA damage and senescence. Thus, our findings reveal a DNA-PK-STAT6 axis enacting a non-canonical type 2 immunity via DNA repair to prevent macrophage senescence, presenting a therapeutic target for healthy aging.