Site-Specific TREM2 Fragment Analysis Within Multi-Analyte CSF Panel for Microglial Priming Detection

This hypothesis proposes that incorporating Parent B’s mechanistically precise site-specific TREM2 fragment ratio analysis (N-terminal vs C-terminal fragments reflecting ADAM10/17 protease activity) into Parent A’s robust multi-analyte framework creates a superior biomarker panel for detecting microglial priming states. The approach combines TREM2 fragment ratios with YKL-40 (neuroinflammatory priming) and neurogranin (synaptic vulnerability) using a weighted algorithm that leverages the specific mechanistic information from TREM2 cleavage patterns. Unlike total sTREM2 levels, fragment ratios directly reflect the balance between homeostatic (low cleavage) and activated (high ADAM10/17-mediated cleavage) microglial states. This mechanistic specificity addresses the interpretation challenges of bulk sTREM2 measurements while maintaining the statistical robustness of a multi-marker approach. The panel would use mass spectrometry to quantify specific TREM2 fragments alongside established ELISA-based measurements of YKL-40 and neurogranin. The weighted algorithm would prioritize TREM2 fragment ratios as the primary microglial activation readout, with YKL-40 and neurogranin providing complementary information about neuroinflammatory context and synaptic integrity. This combination creates a mechanistically-informed composite score that can identify the temporal window when microglia transition from homeostatic surveillance to disease-promoting activation states, providing a more precise biomarker for therapeutic intervention timing than current approaches.