{"ranked_hypotheses": [{"title": "Conserved Synaptic-Mitochondrial Module in AD-Vulnerable Regions", "description": "WGCNA-derived co-expression module containing synaptic vesicle genes (SYN1, SYN2, SYT1) and mitochondrial OXPHOS components (MT-ND1, MT-CO1, UQCRC1) consistently upregulated across prefrontal cortex, hippocampus, and entorhinal cortex in AD, reflecting compensatory synaptic hyperactivity paired with mitochondrial stress response.", "target_gene": "Module hub genes: SYN1, UQCRC1", "composite_score": 0.32, "evidence_for": [{"claim": "Synaptic and mitochondrial dysfunction are established AD hallmarks", "pmid": "PMID:31231128"}, {"claim": "WGCNA identifies reproducible co-expression patterns in brain transcriptomics", "pmid": "PMID:30617273"}, {"claim": "Entorhinal cortex, hippocampus, and PFC show early AD vulnerability", "pmid": "PMID:26753650"}], "evidence_against": [{"claim": "Synaptic genes are consistently downregulated in AD transcriptomic meta-analyses", "pmid": "PMID:30944315"}, {"claim": "Mitochondrial OXPHOS is impaired (reduced complex I/IV activity), not upregulated in AD proteomics", "pmid": "PMID:29353825"}, {"claim": "Bulk tissue RNA-seq cannot resolve cell-type-specific contributions", "pmid": "PMID:31270457"}, {"claim": "Similar synaptic-mitochondrial disruption occurs in PD, FTD, and normal aging", "pmid": "PMID:31542274"}, {"claim": "WGCNA modules frequently fail replication due to batch effects and sample heterogeneity", "pmid": "PMID:32929376"}]}, {"title": "Exosome-Mediated Tau Spreading Module", "description": "Tau pathology spreads via neuron-derived exosomes containing aggregated tau, with specific loading mechanisms (sumoylation, kinases) and uptake via LRP1 receptor on recipient neurons. This pathway explains propagation patterns in human AD brain.", "target_gene": "Rab27a, nSMase2, LRP1, tau", "composite_score": 0.35, "evidence_for": [{"claim": "Exosomes containing tau are detectable in AD patient CSF", "pmid": "PMID:28467893"}, {"claim": "Exosome-mediated tau transfer demonstrated in cell culture models", "pmid": "PMID:27144255"}, {"claim": "Inhibition of exosome release reduces tau spreading in mouse models", "pmid": "PMID:28389758"}], "evidence_against": [{"claim": "Tau-targeted antibodies semorinemab and gosuranemab failed Phase II targeting extracellular tau", "pmid": "PMID:34758345"}, {"claim": "GW4869 (nSMase2 inhibitor) has poor PK and does not cross BBB", "pmid": "unavailable"}, {"claim": "LRP1 knockout causes embryonic lethality and cognitive deficits in mice", "pmid": "PMID:26305630"}, {"claim": "Exosome biology is not disease-specific; blocking affects immune surveillance and synaptic function", "pmid": "PMID:33230315"}]}], "synthesis_summary": "Two hypotheses regarding molecular mechanisms in Alzheimer's disease were evaluated. The Conserved Synaptic-Mitochondrial Module hypothesis proposes coordinated upregulation of synaptic and mitochondrial genes across vulnerable brain regions, but faces significant challenges: bulk tissue RNA-seq cannot resolve cell-type contributions, established AD transcriptomics show synaptic genes are downregulated rather than upregulated, and the same pattern occurs in