Midazolam negatively regulates STING trafficking and activation and protects against Listeria monocytogenes infection in vivo.

The stimulator of interferon genes (STING) plays a critical role in innate immunity, where precise regulation of its activity is essential for pathogen clearance and avoiding harmful immune responses. The development of STING inhibitors has been proposed to alleviate a variety of autoimmune and inflammatory diseases. In this study, using cell line models, we demonstrate that midazolam, a commonly used anesthetic, inhibited STING signaling in macrophages and epithelial-derived cell lines. Specifically, midazolam or translocator protein (TSPO) silencing impaired STING trafficking from the endoplasmic reticulum (ER) to the Golgi apparatus in a proteasome-dependent manner. Furthermore, midazolam effectively suppressed STING over-activation and type I interferons (IFNs) signaling activation induced by STING mutations or excessive DNA accumulation in three-prime repair exonuclease 1 knockout (Trex1-/-) mouse embryonic fibroblasts. Of note, midazolam reduced type I IFNs expression and protected mice against Listeria monocytogenes-induced infection in vivo. These findings suggest that midazolam or TSPO inhibitors could be a promising therapeutic agent for modulating STING activation and treating related inflammatory diseases.