Abstract Targeting myeloid cells, especially microglia, for the treatment of neuroinflammatory diseases such as multiple sclerosis (MS), is underappreciated. Here, we screened a library of compounds and identified the topoisomerase 1 (TOP1) inhibitor camptothecin (CPT) as a promising drug candidate for microglial modulation. CPT and its FDA-approved analog topotecan (TPT) inhibited inflammatory responses in microglia and macrophages, and ameliorated neuroinflammation in mice. Transcriptomic analysis of sorted microglia revealed an altered transcriptional phenotype following TPT treatment, with Ikzf1 identified as a potential target. Importantly, TOP1 expression was found elevated in several neuroinflammatory conditions, including human MS brains. To achieve targeted delivery to myeloid cells we designed a nanosystem using DNA origami and loaded TPT into it (TopoGami). TopoGami also significantly suppressed the inflammatory response in microglia and mitigated disease progression in MS-like mice. Our findings suggest that TOP1 inhibition represents a therapeutic strategy for neuroinflammatory diseases, and the proposed nanosystem may foster future research and drug development with a demand to target myeloid cells.

Nanoengineered DNA origami with repurposed TOP1 inhibitors targeting myeloid cells for the mitigation of neuroinflammation