Chronic Low-Level IFN-γ Expression Disrupts Mitochondrial Complex I Activity in Renal Macrophages: An Early Mechanistic Driver of Lupus Nephritis Pathogenesis

Mitochondrial dysfunction and macrophage dysregulation are well recognized as significant contributors to the pathogenesis of autoimmune diseases. However, the detailed mechanisms connecting these two factors remain poorly understood. This study hypothesizes that low but chronic interferon-gamma (IFN-γ) plays a critical role in these processes. To explore this, we utilized ARE-Del mice, a model characterized by sustained low-level IFN-γ expression and lupus nephritis (LN)-like symptoms. Age- and tissue-dependent gene expression analyses in ARE-Del mice revealed significant suppression of mitochondrial complex I components and activities, particularly in the kidneys. The genotype-dependent suppression of mitochondrial complex I indicates early disruption, which leads to macrophage dysfunction. Notably, remission restored gene expression of mitochondrial complex I and macrophage dysfunction in isolated renal macrophages from NZB/W lupus-prone mice. These findings suggest that chronic low-level IFN-γ disrupts mitochondrial complex I activity in macrophages, highlighting its role in the early pathogenesis of autoimmune diseases like lupus nephritis. This provides new insights into the molecular interactions underlying autoimmune pathogenesis and suggests potential targets for therapeutic intervention.