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Updated: Jan 30, 2026

Screening Bioactive Nanoparticles in Phagocytic Immune Cells for Inhibitors of Toll-like Receptor Signaling
Published on: July 26, 2017
The nitrone spin trap 5,5‑dimethyl‑1‑pyrroline N‑oxide binds to toll-like receptor-2-TIR-BB-loop domain and dampens
Marcos D Muñoz1, Lucas J Gutierrez2, Sandrine Delignat3
1Laboratory of Experimental and Translational Medicine, IMIBIO-SL-School of Chemistry, Biochemistry and Pharmacy, National University of San Luis-CONICET, San Luis, 5700 San Luis, Argentina.
Abstract:
The nitrone spin trap 5,5‑dimethyl‑1‑pyrroline N‑oxide (DMPO) dampens endotoxin-induced and TLR4-driven priming of macrophages, but the mechanism remains unknown. The available information suggests a direct binding of DMPO to the TIR domain, which is shared between TLRs. However, TLR2-TIR domain is the only TLR that have been crystallized. Our in silico data show that DMPO binds to four specific residues in the BB-loop within the TLR2-TIR domain. Our functional analysis using hTLR2.6-expressing HEKs cells showed that DMPO can block zymosan-triggered-TLR2-mediated NF-κB activation. However, DMPO did not affect the overall TLR2-MyD88 protein-protein interaction. DMPO binds to the BB-loop in the TIR-domain and dampens downstream signaling without affecting the overall TIR-MyD88 interaction. These data encourage the use of DMPO-derivatives as potential mechanism-based inhibitors of TLR-triggered inflammation.
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