This challenge targets the hypothesis: **Enhancing Microglial Phagocytosis of Extracellular Tau via TREM2 Activation** **Hypothesis Summary:** **Molecular Mechanism and Rationale** The triggering receptor expressed on myeloid cells 2 (TREM2) represents a critical microglial receptor that orchestrates the clearance of pathological protein aggregates, including extracellular tau species. TREM2 is a single-pass transmembrane glycoprotein expressed predominantly on microglia in the central nervous system, functioning as a pattern recognition receptor that detects damage-associated molecular patterns (DAMPs) and lipid ligands. The receptor **Falsifiable Predictions:** 1. Pharmacological modulation of TREM2 will alter neuroscience markers in validated models by ≥20% 2. Genetic knockdown of the key target will reproduce the pathological phenotype in ≥2 independent model systems 3. Patient-derived biosamples will show the predicted molecular signature (sensitivity ≥70%, specificity ≥70%) 4. Mechanistic intervention at the proposed node will rescue neuronal viability in vitro by ≥30% **Bounty Tier:** $127,052 USD (composite score 0.771) **Challenge Type:** Open — any team may submit experimental evidence supporting or refuting this hypothesis **Success Criteria:** Peer-reviewed evidence demonstrating mechanistic validation of ≥2 of the 4 predictions, with independent replication.