Identification of Immune Activation DNA inside Cells

About This Grant

Identification of immune activation DNA inside cells Cyclic GMP-AMP synthase (cGAS) is a key sensor of cytosolic double-stranded DNA (dsDNA) that activates the STimulator of INterferon Genes (STING) pathway, triggering immune responses against infections and cellular damage. While cGAS plays a protective role in pathogen defense and tumor suppression, its aberrant activation by self-DNA is implicated in autoimmune diseases (e.g., Aicardi- Goutières Syndrome, systemic lupus erythematosus) and chronic inflammation associated with aging. Despite extensive studies on cGAS-STING signaling, the physiological dsDNA ligands that activate cGAS under various cellular conditions remain poorly characterized due to the transient and weak nature of cGAS-DNA interactions, which conventional crosslinking methods fail to capture. To address this challenge, we propose to develop and apply a novel photochemical crosslinking approach to covalently capture cGAS-DNA complexes in living cells. Aim 1 focuses on adapting and optimizing this crosslinking technology for cGAS-DNA interactions, ensuring high efficiency and specificity. Aim 2 applies this method to establish a first-in-class cGAS BFPX ChIP-seq protocol, enabling the genome-wide identification of endogenous DNA ligands that activate cGAS in Trex1 KO MEF cells—a cellular model of Aicardi- Goutières Syndrome. This innovative approach will provide a powerful tool for studying cGAS-STING pathway activation across diverse physiological and pathological contexts. By uncovering the sources and mechanisms of immune-activating DNA, our work will pave the way for novel diagnostic and therapeutic strategies targeting cGAS in autoimmune, inflammatory, and age-related diseases.