Site-specific glycosylation patterns on circulating TREM2 ectodomain fragments reflect the metabolic state and activation history of CNS microglia, serving as predictive biomarkers for anti-neuroinflammatory therapeutic responses. The hypothesis posits that microglial priming states differentially regulate glycosyltransferase expression (particularly ST6GAL1, MGAT5, and FUT8), leading to distinct N-linked and O-linked glycan signatures on TREM2 ectodomains shed into circulation. Unlike CSF fragment ratios that require lumbar puncture, plasma glycan profiling via lectin arrays or mass spectrometry offers accessible monitoring of microglial functional states. The mechanistic foundation rests on established connections between cellular activation, ER stress responses, and glycosylation machinery reprogramming. Primed microglia exhibit altered glucose metabolism and ER proteostasis, directly impacting glycan processing enzymes. Therapeutic interventions targeting neuroinflammation (CSF1R inhibitors, IL-1β antagonists, or TREM2 agonists) would predictably shift microglial metabolism and consequently alter TREM2 glycosylation patterns before clinical symptoms change.

Site-specific glycosylation patterns on circulating TREM2 ectodomain fragments reflect the metabolic state and activation history of CNS microglia, serving as predictive biomarkers for anti-neuroinflammatory therapeutic responses. The hypothesis posits that microglial priming states differentially regulate glycosyltransferase expression (particularly ST6GAL1, MGAT5, and FUT8), leading to distinct N-linked and O-linked glycan signatures on TREM2 ectodomains shed into circulation. Unlike CSF fragment ratios that require lumbar puncture, plasma glycan profiling via lectin arrays or mass spectrometry offers accessible monitoring of microglial functional states. The mechanistic foundation rests on established connections between cellular activation, ER stress responses, and glycosylation machinery reprogramming. Primed microglia exhibit altered glucose metabolism and ER proteostasis, directly impacting glycan processing enzymes. Therapeutic interventions targeting neuroinflammation (CSF1R inhibitors, IL-1β antagonists, or TREM2 agonists) would predictably shift microglial metabolism and consequently alter TREM2 glycosylation patterns before clinical symptoms change. This approach addresses the critical gap in real-time therapeutic monitoring for CNS-targeted interventions. Validation would require correlation studies between plasma TREM2 glycan profiles and known microglial activation markers in neurodegeneration models, followed by longitudinal tracking during therapeutic intervention. The assay development leverages existing glycoproteomics platforms, making implementation more feasible than novel mass spectrometry methods. Clinical relevance centers on personalized medicine applications where baseline glycan signatures could predict therapeutic responsiveness, enabling treatment stratification and reducing failed trials in heterogeneous neurodegenerative populations.