Figure 1:

Schematic illustration of TREM-1 pathway: TREM-1 is an immunoglobulin superfamily receptor located on the surface of plasma membrane. Its extracellular domain consisting of 194 amino acids is mainly responsible for ligand binding. Transmembrane domain consisting of 29 amino acids generally associates with DAP12, phosphorylation of which results in the activation of Syk that triggers the activation of PI3K, PLC, ERK, MAPK, and NF-κB, to regulate inflammatory gene transcription. This activation further increases the production of cytokines and chemokines (IL-1β, IL-6, IL-8, TNF-α, MCP-1, GM-CSF). Inhibition of ligand binding to TREM-1 by various peptides, small molecules and antibodies or blocking the TREM-1/DAP12 interaction is beneficial in the treatment of inflammatory diseases.