Interrupting a mitochondrial DNA-driven innate immune circuit attenuates hepatic tissue remodeling and fibrotic...

Steatohepatitis integrates metabolic stress and mitochondrial damage, but single-node interventions often incompletely quell inflammation and fibrosis. We tested a dual-node strategy that reduces the trigger and blocks the adaptor of the mtDNA-cGAS-STING pathway in a high-fat diet plus streptozotocin mouse model. Male C57BL/6 J mice with steatohepatitis (SH) received urolithin A (UA; mitophagy enhancer), C176 (murine STING inhibitor), or their combination. Endpoints included liver injury (ALT/AST), lipids (serum and hepatic triglycerides, cholesterol), glycemia/insulin resistance (fasting glucose, insulin, HOMA-IR), cGAS-STING/type-I interferon signaling (Ifnb1, Cxcl10, IFN-β, CXCL10; p-STING, p-TBK1, p-IRF3), mitochondrial damage signals (cytosolic mtDNA, mtTFA), autophagy/mitophagy (LC3-II/I, cleaved-PINK1, p-PARKIN, p62), inflammasome/cytokines (NLRP3, IL-1β, TNF-α), and fibrosis (hydroxyproline, Col1a1, Tgfb1/TGF-β1). Compared with SH, UA or C176 monotherapy improved injury, lipid, interferon, and fibrotic readouts, with UA preferentially lowering mtDNA/mtTFA and C176 more strongly suppressing p-STING-TBK1-IRF3 and IFN-β/CXCL10. The combination produced the largest, pathway-concordant effects across domains, frequently approaching CTRL. Formal combination analysis on fractional inhibition showed predominant synergistic activity (ΔBliss and ΔHSA > 0 for most endpoints). A precision-weighted correlation map linked insulin resistance, mitochondrial stress, cGAS-STING activation, and fibrosis, while mitophagy restoration markers correlated inversely. By pairing a mitophagy enhancer with a STING inhibitor, we provide first evidence in this model that coordinated upstream and downstream targeting of the mtDNA-cGAS-STING axis yields superior, multi-domain control of disease biology and is immediately translatable via IFN-β/CXCL10, cell-free mtDNA, and imaging readouts.