TREM1

TREM1, which stands for Triggering Receptor Expressed on Myeloid cells 1, is a type I transmembrane protein belonging to the immunoglobulin superfamily. It is primarily expressed on myeloid cells, including neutrophils, monocytes, and macrophages, particularly during inflammatory responses. TREM1 plays a critical role in amplifying immune responses, especially against bacterial and fungal infections.

Upon binding to its ligands, which are often derived from microbial components or inflammatory mediators, TREM1 initiates intracellular signaling cascades. This signaling typically involves the adaptor protein DAP12 (DNAX-activating protein 12). The activation of TREM1 leads to enhanced pro-inflammatory cytokine production, increased phagocytosis, and the release of antimicrobial substances. This amplification mechanism helps to strengthen the host's defense against pathogens.

TREM1 expression is generally low in healthy tissues but is significantly upregulated at sites of infection and inflammation. Its role in amplifying immune responses means that dysregulation of TREM1 signaling can contribute to excessive inflammation and tissue damage in various pathological conditions, including sepsis, arthritis, and inflammatory bowel disease. Conversely, inhibiting TREM1 signaling has been explored as a therapeutic strategy to dampen exaggerated inflammatory responses. Research continues to investigate the precise molecular mechanisms of TREM1 signaling and its therapeutic potential.