{"ranked_hypotheses":[{"rank":1,"title":"TREM2-ICD Nuclear Translocation as Self-Sustaining Priming Signal","mechanism":"Proteolytic cleavage of TREM2 by ADAM10/γ-secretase releases the intracellular domain, which translocates to the nucleus and cooperates with SPI1/PU.1 at TYROBP promoter regions to establish a feedforward transcriptional circuit that locks microglia in a primed, inflammation-resolving-resistant state independent of membrane SYK/PI3K signaling.","target_gene":"TREM2","confidence_score":0.52,"novelty_score":0.68,"feasibility_score":0.40,"impact_score":0.78,"composite_score":0.598,"key_evidence":"PMID 30206223 (TREM2-ICD nuclear localization in HEK293T/RAW264.7); PMID 30550849 (SPI1-TYROBP cooperation in sorted microglial RNA-seq)","testable_prediction":"CRISPRi-mediated blockade of TREM2 nuclear localization sequence prevents SPI1-driven TYROBP upregulation and reduces cytokine hypersecretion upon secondary challenge in human iPSC-derived microglia","skeptic_concern":"Low-abundance, unstable ICD fragment demonstrated only in overexpression systems; endogenous nuclear accumulation in primary brain microglia under physiological conditions remains undemonstrated; cellular localization may be cell-line artifact","expert_verdict":"Mechanistically compelling but requires primary microglial validation before translational investment; nuclear translocation inhibitors present challenging drug discovery but would be disease-modifying if confirmed"}, {"rank":2,"title":"NLRP3 Inflammasome Hyper-Responsiveness in Primed Microglia","mechanism":"Prior exposure to DAMP signals (e.g., ATP, aggregated Aβ) primes microglial NLRP3 to mount exaggerated IL-1β responses upon secondary exposure, creating a self-reinforcing neuroinflammatory loop that drives tau pathology spread and accelerates neurodegeneration.","target_gene":"NLRP3","confidence_score":0.68,"novelty_score":0.52,"feasibility_score":0.72,"impact_score":0.68,"composite_score":0.645,"key_evidence":"NLRP3 KO mice show reduced Aβ pathology and improved cognition; IL-1β elevation documented in AD brains and prodromal CSF; in vitro priming protocols well-established","testable_prediction":"Microglia-specific NLRP3 conditional knockout crossed to 5xFAD mice will show attenuation of tau hyperphosphorylation and synapse loss independent of amyloid burden","skeptic_concern":"NLRP3 is upstream of broad inflammatory pathways; specificity to microglial priming versus general inflammatory enhancement remains unresolved; compensatory mechanisms may limit therapeutic efficacy","expert_verdict":"Highest translational feasibility among inflammasome targets; MCC950 inhibitor already in preclinical development with favorable safety profile; pipeline-ready within 5-7 years if animal efficacy confirms"}, {"rank":3,"title":"sTREM2 as State-Dependent Biomarker of Microglial Priming","mechanism":"Soluble TREM2 shed by ADAM10/ADAM17 cleavage reflects microglial activation state, with elevated CSF sTREM2 correlating with early tau pathology and representing a potential readout for microglial transition from homeostatic to primed/warning state.","target_gene":"TREM2","confidence_score":0.70,"novelty_score":0.45,"feasibility_score":0.80,"impact_score":0.58,"composite_score":0.638,"key_evidence":"Multiple independent cohorts (Knight Initiative,-banner) consistently show CSF sTREM2 elevation in early AD; correlates with tau PET and CSF p-tau181; sTREM2 levels modulated by TREM2 R47H variant","testable_prediction":"Longitudinal sTREM2 measurement in preclinical carriers will predict conversion to MCI with superior accuracy compared to baseline amyloid alone, indicating priming precedes symptomatic decline","skeptic_concern":"sTREM2 is a correlative biomarker, not mechanistic driver; cannot distinguish protective versus harmful microglial activation; does not resolve whether elevation reflects beneficial phagocytosis or maladaptive inflammation","expert_verdict":"Near-term translational opportunity as stratification tool; validation studies should employ single-cell proteomics to resolve sTREM2 cellular origin; biomarker qualification path is 3-5 years if prospective trials confirm predictive value"}, {"rank":4,"title":"Disease-Associated Microglia (DAM) Signature as Composite Priming State","mechanism":"TREM2-dependent acquisition of DAM transcriptional identity upon amyloid deposition involves coordinated downregulation of P2RY12/CX3CR1 and upregulation of CLEC7A/APOE, representing a staged microglial response that is initially protective but transitions to neurotoxicity when metabolic stress or aging compromises homeostatic resolution.","target_gene":"TREM2","confidence_score":0.75,"novelty_score":0.42,"feasibility_score":0.68,"impact_score":0.72,"composite_score":0.663,"key_evidence":"Single-cell RNA-seq consistently identifies DAM cluster in mouse AD models and human AD brain; TREM2 R47H impairs DAM formation; APOE4 allele exacerbates DAM inflammatory signature","testable_prediction":"Single-nucleus ATAC-seq of TREM2 R47H vs. WT microglia will identify causative regulatory elements driving impaired DAM transition, enabling targeted epigenetic intervention","skeptic_concern":"DAM may be epiphenomenon rather than driver; heterogeneity within cluster obscures functional subpopulations; human vs. mouse DAM identity shows species-specific divergence limiting cross-species translation","expert_verdict":"Most comprehensive framework integrating multiple genetic risk factors; therapeutic targeting requires subpopulation-specific approach to avoid broad immunomodulation; staged intervention at early-stage DAM may preserve neuroprotection while blocking transition to dysregulation"}],"consensus_points":["TREM2 is centrally positioned as a genetic risk factor