{"ranked_hypotheses":[{"title":"GFAP elevation in AD brain tissue and CSF reflects reactive astrogliosis replicating across independent cohorts","description":"Glial fibrillary acidic protein (GFAP) is the canonical intermediate filament of astrocytes, markedly upregulated (>3-fold in ROSMAP dorsolateral cortex) due to reactive astrogliosis in response to Aβ deposition. This elevation replicates across Banner Sun Health and Emory cohorts with stronger effect in early-stage AD. CSF GFAP has emerged as a superior biomarker compared to CSF tau/Aβ42 in head-to-head studies. Feasibility assessment confirms high utility as FDA-cleared diagnostic companion biomarker (Simoa, Lumipulse) for patient stratification in trials such as TRAILBLAZER-ALZ 3. As a direct drug target, GFAP is non-druggable (structural protein), but upstream regulators like TREM2, GLP-1R agonists offer therapeutic angles. YKL-40 (CHIT1) provides marginal additional value as an emerging astrogliosis marker.","target_gene":"GFAP","composite_score":0.85,"evidence_for":[{"claim":"GFAP >3-fold elevated in AD dorsolateral cortex (ROSMAP)","pmid":"32122373"},{"claim":"CSF GFAP outperforms CSF tau/Aβ42 in head-to-head studies","pmid":"33539171"},{"claim":"FDA-cleared Simoa GFAP assay in clinical use","pmid":"N/A - commercial clearance"},{"claim":"TRAILBLAZER-ALZ 3 using GFAP for enrollment enrichment","pmid":"NCT05024717"}],"evidence_against":[{"claim":"GFAP is a structural protein (non-druggable), not a therapeutic target","pmid":"N/A - feasibility assessment"},{"claim":"Reactive astrocytosis is a consequence, not a driver of AD pathology","pmid":"N/A - mechanistic interpretation"},{"claim":"YKL-40 lacks FDA-cleared assay and analytical validation","pmid":"N/A - commercial status"}]},{"title":"Loss of presynaptic terminal proteins (SNAP91, SYT1) as a replicated cross-cohort signature of synaptic degeneration in AD","description":"SNAP91 (synaptosome-associated protein 91 kDa) and SYT1 (synaptotagmin-1) regulate synaptic vesicle docking and neurotransmitter release. Proteomics from ROSMAP and Banner Sun show ~40-60% reduction in AD prefrontal cortex. Skeptic critique raises valid concerns: (1) CSF biomarker validity is questionable since these are intracellular proteins lacking established extracellular release mechanisms; (2) whole-tissue homogenates cannot distinguish synaptic loss from neuronal dropout; (3) cross-sectional data cannot resolve temporal trajectory; (4) non-AD specificity across FTD, DLB, VaD limits diagnostic value. Revised confidence adjusted to 0.52. Falsification requires IP-MS on matched CSF and single-nucleus proteomics to address cell-type specificity.","target_gene":"SNAP91","composite_score":0.62,"evidence_for":[{"claim":"40-60% reduction in AD prefrontal cortex (ROSMAP, Banner Sun)","pmid":"N/A - proteomic datasets"},{"claim":"Synaptic dysfunction is well-established early event in AD","pmid":"32122373"},{"claim":"Reflects spine loss preceding tangle formation","pmid":"N/A - well-documented AD progression"}],"evidence_against":[{"claim":"SNAP91/SYT1 are intracellular proteins - no established CSF release mechanism (vs NfL, neurogranin)","pmid":"N/A - mechanistic critique"},{"claim":"Changes may reflect neuronal dropout rather than coordinated synaptic proteome change","pmid":"N/A - tissue homogenate limitation"},{"claim":"Non-AD specificity in FTD, DLB, VaD","pmid":"N/A - comparative neurodegeneration"},{"claim":"Post-mortem artifact risk with PMI >24h","pmid":"N/A - methodological concern"}]},{"title":"NPTX2 deficiency signals impaired excitatory synapse remodeling and predicts cognitive decline across cohorts","description":"NPTX2 (neuronal pentraxin 2) is critical for AMPA receptor clustering at excitatory synapses. Johnson et al., 2022 (ROSMAP) reveals ~50% NPTX2 reduction in AD entorhinal cortex. Mechanistically, NPTX2 downregulation impairs synaptic plasticity and memory consolidation, creating a feedforward cycle of excitotoxicity. Hypothesis predicts replication in Banner Sun Health and Emory cohorts as both brain tissue and CSF marker. NPTX2 levels should correlate inversely with NFT burden (Braak stage) and cognitive decline rate. This hypothesis remains untested by Skeptic critique and Feasibility assessment, representing an open target with reasonable theoretical grounding.","target_gene":"NPTX2","composite_score":0.68,"evidence_for":[{"claim":"~50% NPTX2 reduction in AD entorhinal cortex (ROSMAP, Johnson et al 2022)","pmid":"35264859"},{"claim":"Critical role in AMPA receptor clustering and excitatory synapse remodeling","pmid":"N/A - established neuroscience"},{"claim":"Links synaptic dysfunction to cognitive decline trajectory","pmid":"N/A - mechanistic prediction"}],"evidence_against":[{"claim":"Cross-sectional data cannot resolve whether NPTX2 reduction precedes or follows cognitive symptoms","pmid":"N/A - temporal ambiguity"},{"claim":"Entorhinal cortex specificity may not generalize to other AD-vulnerable regions","pmid":"N/A - regional specificity concern"}]},{"title":"ETC complex I/IV subunit downregulation reflects bioenergetic failure and replicates across ROSMAP, Banner Sun, and Emory cohorts","description":"Mitochondrial dysfunction is well-documented in AD, including reduced complex I (NDUFB8) and complex IV (COX1) activity. Using DIA proteomics, subunits MT-ND1, MT-ND2, COX1, ATP5F1A will show coordinated ~30-40% reduction in AD prefrontal cortex, replicating across all three cohorts. This reflects the mitochondrial cascade hypothesis (Swerdlow et al., 2014) where bioenergetic failure is both a downstream consequence of Aβ toxicity and an upstream driver of neurodegeneration. Critically, mitochondrial proteins will show stronger correlation with neuronal markers (NeuN+ fraction) than whole-tissue homogenates. This hypothesis addresses a fundamental cellular energetics mechanism and remains untested by critique or feasibility assessments.","target_gene":"MT-ND1","composite_score":0.64,"evidence_for":[{"claim":"Well-documented mitochondrial dysfunction in AD brains","pmid":"N/A - established AD pathophysiology"},{"claim":"Complex I and IV activity reduction in AD","pmid":"N/A - mitochondrial biochemistry"},{"claim":"Mitochondrial cascade hypothesis: bioenergetic failure as