prion-therapeutic-development

Anti-Prion Therapeutic Development: High-Throughput Screening and Validation

Overview

Anti-Prion Therapeutic Development: High-Throughput Screening and Validation

Overview

This experiment aims to identify and develop [therapeutic agents](/therapeutics/) that can prevent [prion protein](/entities/prnp) conversion, clear existing [prion](/entities/prnp) aggregates, and ultimately rescue neuronal function in [prion disease](/diseases/). The study combines [high-throughput screening](/technologies/high-throughput-screening) with mechanism-focused validation to advance candidates toward clinical translation. This connects to the broader [anti-prion therapeutic development](/therapeutics/) literature and [prion-like propagation](/mechanisms/extracellular-vesicle-tnt-mediated-spreading-comparison) strategies.

Scientific Rationale

Current treatment for prion diseases is entirely supportive, with no disease-modifying therapies available. The discovery that antisense oligonucleotides (ASOs) can extend survival in prion-infected mice (Raymond et al., 2019) has renewed interest in therapeutic development. However, several key challenges remain:

This experiment addresses these challenges through a systematic approach combining target-based and phenotype-based screening.

Hypothesis

Combination therapy targeting both [prion formation](/entities/prnp) (via [PrP^C](/entities/prnp) reduction) and [prion clearance](/mechanisms/prion-propagation-mechanism) (via aggregation blockers) will provide superior efficacy compared to single-mechanism approaches, with a therapeutic window extending into early symptomatic disease. This parallels [combination therapy](/mechanisms/pd-combination-therapy-matrix) strategies in [Parkinson's disease](/diseases/parkinsons-disease) and [Alzheimer's disease](/diseases/alzheimers-disease).

Experimental Design

Phase 1: High-Throughput Screening (Months 1-8)

Primary screen: Aggregation inhibitor library

• Screen 50,000 compounds using cell-based prion aggregation assay
• Use PK1 cells (mouse neuroblastoma with persistent prion infection)
• Readout: PrP^Sc levels via PK digestion and Western blot
• Counter-screen: Cytotoxicity in uninfected cells

• Screen 2,000 FDA-approved drugs
• Include CNS-penetrant compounds prioritized
• Test in multiple prion strains (RML, 22L, FDC)

• Screen 200 ASO sequences targeting PRNP mRNA
• Test knockdown efficiency and duration
• Evaluate for splice-modulating ASOs

Phase 2: Mechanism-Focused Validation (Months 6-18)

Lead optimization:

• Test concentration-response for top 50 hits
• Evaluate blood-brain barrier penetration (in vitro PAMPA, in situ brain uptake)
• Assess duration of effect

• Determine mode of action: aggregation blocker vs. clearance enhancer vs. production inhibitor
• Test in neurons (iPSC-derived) and astrocytes
• Evaluate effect on prion strains

• Test synergistic combinations:
• ASO + aggregation blocker
• Aggregation blocker + clearance enhancer
• Triple combination

Phase 3: In Vivo Validation (Months 12-24)

Mouse efficacy studies:

• Test top 5 candidates in prion-infected mice (RML model)
• Routes of administration: ICV, IV, oral
• Endpoints: survival, clinical score, PrP^Sc burden, neuronal preservation
• Establish dose-response and therapeutic window

• GLP toxicology for top 2 candidates
• Off-target analysis
• Assessment of PrP^C knockdown effects

• Formulation development
• GMP manufacturing
• Regulatory pre- consultation

Expected Outcomes

Key Metrics

| Metric | Target |
|--------|-------|
| Screen hits | ≥100 with >50% PrP^Sc reduction |
| Lead compounds | ≥5 with in vivo efficacy |
| Survival extension | ≥30% in mouse model |
| Therapeutic window | Benefit in early symptomatic disease |

Feasibility Assessment

• Technical feasibility: HIGH — established HTS platforms and prion mouse models
• Previous success: ASO approach showed 50% survival extension in mice
• Timeline: 24 months to identify clinical candidates

Cost Estimate

| Component | Cost (USD) |
|-----------|------------|
| HTS screening | $400,000 |
| Lead optimization | $300,000 |
| In vivo studies | $500,000 |
| Safety assessment | $350,000 |
| IND-enabling studies | $500,000 |
| Personnel (4 FTE × 2 years) | $600,000 |
| Total | $2,650,000 |

Risk Mitigation

• Risk: Poor BBB penetration → Mitigation: Prioritize CNS-penetrant compounds in screen
• Risk: Toxicity from PrP^C knockdown → Mitigation: Use ASOs with partial knockdown, test in PrP^+/+ and PrP^+/- models
• Risk: Strain variability limiting applicability → Mitigation: Test against multiple strains

Cross-Disease Therapeutic Connections

Anti-[prion](/entities/prnp) therapeutic strategies connect to [protein aggregation](/mechanisms/mutant-huntingtin-aggregation) therapeutics across [neurodegenerative diseases](/diseases/):

Similar Aggregation-Targeting Approaches

• [Anti-aggregation compounds](/therapeutics/aggregation-inhibitors-huntingtons): [Flupirtine](/therapeutics/aggregation-inhibitors-huntingtons), [HSP70](/proteins/hsp70-protein) modulators, [ Congo red](/therapeutics/aggregation-inhibitors-huntingtons) derivatives — tested across [prion](/entities/prnp), [α-synuclein](/proteins/alpha-synuclein), [tau](/proteins/tau), [HTT](/genes/htt)
• [Immunotherapy](/therapeutics/alpha-synuclein-antibodies): [Anti-prion antibodies](/therapeutics/anti-prion-antibodies), [anti-α-synuclein antibodies](/therapeutics/alpha-synuclein-antibodies), [anti-tau antibodies](/therapeutics/anti-tau-antibodies) — clear extracellular aggregates
• [ASOs](/therapeutics/antisense-oligonucleotides): [Tominersen](/therapeutics/tominersen) for [HD](/diseases/huntingtons), [ASOs targeting SOD1](/therapeutics/antisense-oligonucleotides) for [ALS](/diseases/amyotrophic-lateral-sclerosis), [BIIB080](/therapeutics/antisense-oligonucleotides) for [AD](/diseases/alzheimers-disease)
• [Small molecule degraders](/therapeutics/proteolysis-targeting-chimeras-neurodegeneration): [PROTACs](/therapeutics/proteolysis-targeting-chimeras-neurodegeneration) for [tau](/proteins/tau), [α-synuclein](/proteins/alpha-synuclein)

Key Proteins with Aggregation-Targeting Strategies

| Protein | Disease | Aggregation Mechanism | Therapeutic Approach |
|---------|---------|----------------------|----------------------|
| [PrP^Sc](/entities/prnp) | [Prion disease](/diseases/creutzfeldt-jakob-disease) | β-sheet conversion | [ASOs](/therapeutics/antisense-oligonucleotides), antibodies |
| [α-synuclein](/proteins/alpha-synuclein) | [PD](/diseases/parkinsons-disease), [DLB](/diseases/dementia-lewy-bodies) | NAC domain aggregation | [Immunotherapy](/therapeutics/alpha-synuclein-antibodies), [ASOs](/therapeutics/antisense-oligonucleotides) |
| [Tau](/proteins/tau) | [AD](/diseases/alzheimers-disease), [PSP](/diseases/progressive-supranuclear-palsy) | Microtubule-binding repeat domain | [Methylene blue](/therapeutics/methylene-blue-alzheimers), [ASOs](/therapeutics/antisense-oligonucleotides) |
| [mHTT](/genes/htt) | [Huntington's disease](/diseases/huntingtons) | Polyglutamine expansion | [ASOs](/therapeutics/antisense-oligonucleotides), [PROTACs](/therapeutics/proteolysis-targeting-chimeras-neurodegeneration) |
| [TDP-43](/proteins/tardbp) | [ALS](/diseases/amyotrophic-lateral-sclerosis), [FTD](/diseases/frontotemporal-dementia) | C-terminal domain aggregation | [ASOs](/therapeutics/antisense-oligonucleotides), [aggregation inhibitors](/therapeutics/aggregation-inhibitors-huntingtons) |

References

Pathway Diagram

The following diagram shows the key molecular relationships involving prion-therapeutic-development discovered through SciDEX knowledge graph analysis: