Neutralization of pro-inflammatory monocytes by targeting TLR2 dimerization ameliorates colitis

Area of Science:

• Immunology
• Gastroenterology
• Molecular Biology

Background:

• Monocytes are key drivers of acute inflammation.
• Toll-like receptor 2 (TLR2) plays a crucial role in inflammatory responses.
• Dysregulated monocyte activation contributes to inflammatory bowel diseases like colitis.

Purpose of the Study:

• To investigate the therapeutic potential of inhibiting Toll-like receptor 2 (TLR2) dimerization in DSS-induced colitis.
• To elucidate the mechanism by which TLR2 dimerization influences pathogenic monocyte activation.
• To evaluate a novel TLR2 transmembrane peptide (TLR2-p) as a therapeutic agent.

Main Methods:

• Utilized a DSS-induced colitis mouse model.
• Administered a TLR2 transmembrane peptide (TLR2-p) to inhibit TLR2 dimerization.
• Assessed monocyte recruitment and activation markers (Ly6C).
• Measured levels of extracellular signal-regulated kinases (ERK) signaling.
• Quantified pro-inflammatory cytokine secretion (IL-6, IL-23, IL-12, IL-1β).

Main Results:

• TLR2-p ameliorated DSS-induced colitis.
• TLR2-p specifically inhibited the activation of Ly6C(+) monocytes without affecting their recruitment.
• TLR2-p directly interacted with TLR2, preventing TLR2-TLR6/1 assembly.
• Observed decreased ERK signaling and reduced pro-inflammatory cytokine levels.

Conclusions:

• TLR2 dimerization is essential for the activation of pathogenic pro-inflammatory Ly6C(hi) monocytes.
• TLR2-p effectively inhibits TLR2-mediated monocyte activation.
• Inhibition of TLR2 aggregation by TLR2-p shows therapeutic promise for acute gut inflammation.