Mechanistic description
Shared mechanism across FTD, ALS, AD: Progranulin insufficiency causes tau-negative, ubiquitin-positive FTD and weakens lysosomal handling in neurons and microglia. That lysosomal/microglial deficit can sensitize TDP-43 proteinopathy in ALS-spectrum disease and intensify AD inflammatory damage even when GRN is not the initiating lesion.
Falsifiable prediction: Restoring progranulin should improve lysosomal acidification and reduce TDP-43 or amyloid-induced microglial cytokine output by at least 20% across GRN-FTD neurons, TDP-43 ALS neurons, and AD microglia co-cultures.
Proposed experiment: Compare recombinant progranulin, GRN gene augmentation, and control treatment in GRN-haploinsufficient cortical neurons, TDP-43 motor-neuron cultures, and AD microglia-neuron co-cultures; assay cathepsin activity, lysosomal pH, TDP-43 aggregation, cytokines, and neuronal survival.
Cross-disease confidence rationale: Direct FTD genetics with mechanistic extension through TDP-43/microglial lysosomal biology.
Internal SciDEX support: SciDEX support query found 17 matching hypotheses across 5 disease labels, including 17 with debate_count > 0.
Generated by task ffd81f3a-7f04-4db1-8547-1778ce030e89 as a cross-disease mechanism synthesis, not a single-disease hypothesis renamed as multi-disease.
Mechanism / pathway
- GRN
- Progranulin lysosomal function, microglial activation, and TDP-43 risk
- multi
Evidence for (3)
GRN mutations cause tau-negative FTD linked to chromosome 17.
Null GRN mutations cause ubiquitin-positive FTD.
TREM2-APOE dysfunctional microglia framework supports inflammatory convergence.
Evidence against (1)
Evidence matrix
Supporting
- GRN mutations cause tau-negative FTD linked to chromosome 17. PMID:16862116 · 2006 · 10.1038/nature05016
- Null GRN mutations cause ubiquitin-positive FTD. PMID:16862115 · 2006 · 10.1038/nature05017
- TREM2-APOE dysfunctional microglia framework supports inflammatory convergence. PMID:28930663 · 2017 · 10.1016/j.immuni.2017.08.008
Contradicting
No contradicting evidence recorded.
Top-ranked evidence
trust_score × relevance_score × exp(-recency_weight × recency_days / 365)
Supports · top 3
- #1 37b79a50-e9ff-4954-969d-b9a78f891f4c 0.471
- #2 6643dabd-5e6b-4bff-b7a2-ce5d87c0cae3 0.471
- #3 paper-66c463f4292d 0.236
Cite this hypothesis
Cite this hypothesis
etl-backfill (2026). GRN/progranulin lysosomal insufficiency across FTD, ALS-spectrum stress, and AD…. SciDEX hypothesis. https://prism.scidex.ai/hypotheses/h-cross-synth-grn-lysosomal-microglia
@misc{scidex_hypothesis_hcrosssy,
title = {GRN/progranulin lysosomal insufficiency across FTD, ALS-spectrum stress, and AD…},
author = {etl-backfill},
year = {2026},
howpublished = {SciDEX hypothesis},
url = {https://prism.scidex.ai/hypotheses/h-cross-synth-grn-lysosomal-microglia},
note = {SciDEX artifact hypothesis:h-cross-synth-grn-lysosomal-microglia}
}