Exosomes packaged chromatin with dynamic H3R26me2s modification prevents cellular inflammation by blocking the cGAS-STING pathway [CUT&Tag-seq]

Exosomes DNA derived from genomic and mitochondrial could modulate type I IFN expression by triggering the cGAS-STING pathway. However, the chromatin modification of secreted exosomes involved in this process is largely unknown. Here, we could detect the histone H3R26me and H3K27ac in the components of secreted exosomes, meanwhile, a global decrease of H3R26 symmetric dimethylation (H3R26me2s) accompanied by the lowering enrichment of H3K27ac, and this distribution pattern was able to be verified by decreased H3R26me2s leading to the reduction of H3K27ac. Furthermore, these fragmented chromatins trans-located into cytoplasmic could repress cGAS-STING induction of IFNß1 expression, which is further packaged into the exosomes. Collectively, our findings elucidate a novel pathway that which cells can actively transport the chromatin fragments of altered histone arginine methylation to alleviate the stimulation by damaged DNA. We perform ChIP-seq to analysis the changes of histone modification in cells treated with bleomycin. Overall design: Xiaoguang Ren