Characterization of Clonixeril as a Positive Modulator of DMXAA-Induced Murine STING Signaling

Stimulator of Interferon Genes (STING) is a central mediator of innate immune signaling and a therapeutic target for inflammatory diseases. Previously, we identified Clonixeril (CXL) as a concentration-dependent inhibitory modulator of human STING (hSTING) signaling. Despite structural conservation, murine STING (mSTING) and hSTING differ in ligand recognition and activation. We posit that CXL may exhibit distinct activity in the murine system. Mice are used in biomedical research due to their genetic similarities to humans and their utility in evaluating systemic activity and safety of therapeutic compounds. We evaluated CXL effects on mSTING using computational modeling, as well as in vitro and in vivo studies. Molecular dynamics simulations and induced-fit docking predicted favorable CXL binding to mSTING. In 3T3-L1 cells, CXL enhanced DMXAA-induced STING, TBK1, and IRF3 phosphorylation and IFN-β mRNA expression, showing STING pathway activation. Acute CXL efficacy was evaluated in vivo in C57BL/6 mice. CXL increased IFN-β following DMXAA administration. Histopathology showed no treatment-associated abnormalities. HPLC detected CXL in serum and liver. The study identified species-specific responses, suggesting that mouse models may not accurately reflect the effects of CXL on hSTING signaling. Acute CXL treatment was well-tolerated, and CXL is a positive modulator of DMXAA-induced mSTING signaling in vivo.