S8

S8 is a small molecule agonist of the Triggering Receptor Expressed on Myeloid cells-2 (TREM2) currently in preclinical development for the treatment of Alzheimer's disease. Developed by researchers at the University of Kentucky, S8 was identified as part of a series of submicromolar and low-micromolar TREM2 binders (including the lead compound S9) designed to overcome the limitations of antibody-based TREM2 therapeutics, such as poor blood-brain barrier penetration and manufacturing scalability. S8 exhibits a binding affinity (Kd) of approximately 1.1 µM for the TREM2 receptor. Like its closely related analog S9, S8 is designed to modulate microglial function by inducing proximal Syk phosphorylation, activating downstream NFAT transcriptional signaling, and enhancing microglial phagocytic capacity and APOE internalization. These small molecule agonists aim to suppress amyloid-beta (Aβ)-induced neuroinflammation and preserve synaptic integrity, offering a promising therapeutic strategy for neurodegenerative diseases.