TREM2 in Neurodegenerative Diseases: Mechanisms and Therapeutic Potential.

Neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), represent significant global health challenges, affecting millions and straining healthcare systems. These disorders involve progressive neuronal loss and cognitive decline, with incompletely elucidated underlying mechanisms. Chronic neuroinflammation is increasingly recognized as a critical contributor to disease progression. The brain's resident immune cells, microglia, are central to this inflammatory response. When overactivated, microglia and other immune cells, such as peripheral macrophages, can exacerbate inflammation and accelerate disease development. Triggering Receptor Expressed on Myeloid Cells 2 (TREM2) is a transmembrane receptor of the immunoglobulin superfamily that demonstrates high expression on microglia in the central nervous system. TREM2 serves a vital role in regulating phagocytosis, synaptic pruning, and energy metabolism. This review examines the functions of TREM2 in neurodegenerative diseases and its potential as a therapeutic target, aiming to inform future treatment strategies.