Experiment Proposal (crux): Plasma p-tau217-Triggered Exosome Dosing Maximizes lncRNA-0021 Therapeutic Window in AD — hypothesis chain depends on multiple unproven causal links with no evidence for

AIMS

HYPOTHESES

PROTOCOL SUMMARY

Phase 1 - Molecular Identity Discovery (Weeks 1-6): Perform exhaustive transcriptomic analysis using RNA-seq on: (a) frontal cortex tissue from AD (n=10) and age-matched controls (n=10) from ROSMAP; (b) exosomes isolated from plasma of these same subjects via ultracentrifugation (100,000g, 18h) and CD9/CD81/CD63 immunocapture; (c) neuronal cell lines (SH-SY5Y, iPSC-derived neurons) under stress conditions (okadaic acid 5nM for 24h to induce tau hyperphosphorylation). Bioinformatically filter for annotated lncRNA loci (Ensembl GRCh38) and orphan transcripts (lncRNA-0021 naming convention suggests a predicted/putative identifier). Design qRT-PCR assays flanking three distinct genomic regions of candidate transcripts. Confirm specificity via Sanger sequencing and RACE (5' and 3') to obtain full-length sequences. Phase 2 - Biomarker Correlation Analysis (Weeks 4-8): Conduct targeted qRT-PCR quantification of lncRNA-0021 candidate(s) in: (a) matched brain tissue RNA extracts (AD vs control); (b) plasma-derived exosomal RNA; (c) cortical neuronal cell lysates. Perform Spearman correlation against available plasma p-tau217 (SIMOA) and CSF p-tau217 measurements from same subjects. Establish whether lncRNA-0021 expression rises or falls with AD pathology burden. Phase 3 - Exosome Dosing Validation (Weeks 7-12): Engineer exosomes from HEK293T cells via ultracentrifugation, loading lncRNA-0021 via electroporation (Amaxa 4D, pulse code EO-115). Dose iPSC-derived cortical neurons with graded exosome concentrations (0, 10^7, 10^8, 10^9 particles/mL) 24h post okadaic acid treatment (5nM). Harvest cells at 6h, 24h, 48h, 72h post-dose. Assess: (a) intracellular lncRNA-0021 uptake via qRT-PCR and fluorescence in situ hybridization (FISH); (b) GSK-3β Ser9-phosphorylation via Western blot; (c) NF-κB p65 nuclear translocation via immunofluorescence confocal microscopy; (d) LC3-II/LC3-I ratio and p62 degradation as autophagy flux markers. Define dose-response curves and therapeutic window parameters. Phase 4 - In Vivo Proof-of-Concept (Weeks 10-14, optional extension): Administer lncRNA-0021-loaded exosomes to 5xFAD mice via tail vein injection at matched to plasma p-tau217-correlated doses vs fixed doses. Assess brain penetration via qRT-PCR of brain tissue, neuroinflammatory markers, and cognitive behavioral testing (Morris water maze).

PREDICTED OBSERVATIONS

If H1-H4 are supported: RNA-seq will identify a specific transcript corresponding to the lncRNA-0021 nomenclature, with sequence validated by RACE; qRT-PCR will show detectable lncRNA-0021 in AD brain tissue and exosomes with expression levels correlating positively with plasma p-tau217 (Spearman ρ > 0.5, p < 0.05); exosomal lncRNA-0021 uptake will be dose-dependent in neurons; GSK-3β phosphorylation will decrease significantly at the highest doses (e.g., p-GSK-3β/GSK-3β ratio reduced by ≥40%); NF-κB nuclear translocation will be inhibited (p65 nuclear/cytoplasmic ratio reduced by ≥30%); autophagy markers will show increased LC3-II/LC3-I ratio and decreased p62. The therapeutic window (defined as gap between lowest effective dose and highest dose before cytotoxicity) will be quantifiable. If H1 is falsified: No transcript will be detectable matching lncRNA-0021 criteria in any AD or control tissue or exosomes, indicating the entity does not exist as proposed.

FALSIFICATION CRITERIA

F1: RNA-seq across all AD and control samples (brain, exosomes, stressed neurons) fails to identify any transcript matching the lncRNA-0021 locus/nomenclature within detection limits (≥1 transcript per million, TPM). F2: Candidate lncRNA transcripts identified show no correlation with plasma p-tau217 (Spearman |ρ| < 0.3, p > 0.10). F3: Exosomal delivery of lncRNA-0021 candidate fails to produce detectable intracellular uptake in neurons above baseline (<2-fold change vs mock). F4: None of the three proposed downstream mechanisms (GSK-3β, NF-κB, autophagy) show statistically significant changes (p > 0.05, ANOVA with Bonferroni correction) across any dose level. F5: Significant cytotoxicity (cell viability <70% by MTT/PrestoBlue) observed at the lowest exosome dose, eliminating any therapeutic window. If any two of F1-F5 are met, the hypothesis chain is falsified; if F1 alone is met (no molecular identity exists), the entire hypothesis is irreparably falsified regardless of other results.

DATASET DEPENDENCIES