DNA Damage Repair Deficiency Validation Study in Parkinson's Disease

Study Overview

| Attribute | Value |
|-----------|-------|
| Study Type | Preclinical + Clinical Biomarker |
| Duration | 36 months |
| Phase | Proof-of-Concept |
| Primary Endpoint | CSF 8-oxoG correlation with disease progression |
| Secondary Endpoints | PARP activity, DNA repair enzyme levels |

Hypothesis

Impaired [DNA damage repair](/mechanisms/dna-damage-repair) capacity in [dopaminergic neurons](/cell-types/dopaminergic-neurons-substantia-nigra) drives [neurodegeneration](/diseases/) in [Parkinson's disease](/diseases/parkinsons-disease). Targeting this pathway — via [PARP inhibition](/mechanisms/dna-damage-response-cbs), [NAD+](/therapeutics/nicotinamide-riboside-nad-booster) augmentation, or [DNA repair](/mechanisms/dna-damage-repair) enhancement — will slow disease progression.

Study Design

Phase 1: Preclinical Validation (Months 1-18)

In Vitro Experiments

Experiment 1: DNA Damage Assessment in Patient-Derived Neurons

• Cell lines: iPSC-derived dopaminergic neurons from:
• PD patients (LRRK2 G2019S, GBA N370S, idiopathic)
• Healthy controls
• Ataxia-telangiectasia (ATM±) carriers (positive control)
• Assays:
• Comet assay (alkaline) for total DNA damage
• 8-oxoG immunostaining quantification
• γH2AX foci counting (DSB marker)
• OGG1 activity measurement
• Sample size: 15 lines per group

Study Overview

| Attribute | Value |
|-----------|-------|
| Study Type | Preclinical + Clinical Biomarker |
| Duration | 36 months |
| Phase | Proof-of-Concept |
| Primary Endpoint | CSF 8-oxoG correlation with disease progression |
| Secondary Endpoints | PARP activity, DNA repair enzyme levels |

Hypothesis

Impaired [DNA damage repair](/mechanisms/dna-damage-repair) capacity in [dopaminergic neurons](/cell-types/dopaminergic-neurons-substantia-nigra) drives [neurodegeneration](/diseases/) in [Parkinson's disease](/diseases/parkinsons-disease). Targeting this pathway — via [PARP inhibition](/mechanisms/dna-damage-response-cbs), [NAD+](/therapeutics/nicotinamide-riboside-nad-booster) augmentation, or [DNA repair](/mechanisms/dna-damage-repair) enhancement — will slow disease progression.

Study Design

Phase 1: Preclinical Validation (Months 1-18)

In Vitro Experiments

Experiment 1: DNA Damage Assessment in Patient-Derived Neurons

• Cell lines: iPSC-derived dopaminergic neurons from:
• PD patients (LRRK2 G2019S, GBA N370S, idiopathic)
• Healthy controls
• Ataxia-telangiectasia (ATM±) carriers (positive control)
• Assays:
• Comet assay (alkaline) for total DNA damage
• 8-oxoG immunostaining quantification
• γH2AX foci counting (DSB marker)
• OGG1 activity measurement
• Sample size: 15 lines per group

• Method: Live-cell imaging with PARylation sensor
• Stimuli: Hydrogen peroxide (100µM), rotenone (1µM), MPTP (10µM)
• Readouts: PARylation kinetics, NAD+ depletion rate, cell viability
• Inhibitor arm: Olaparib (10µM), rucaparib (5µM)

• Patient samples: Peripheral blood mononuclear cells (PBMCs)
• Tests:
• Base excision repair assay (BER)
• Nucleotide excision repair assay (NER)
• DNA damage sensitivity to UV, oxidative stress
• Correlation: With age of onset, disease severity (MDS-UPDRS)

In Vivo Experiments

Experiment 4: Mouse Model Characterization

• Model: MitoPark mice (mitochondrial complex I deficiency)
• Assessments:
• 8-oxoG levels in substantia nigra (IHC)
• PARP1 activation (Western blot)
• OGG1 expression (qPCR, IHC)
• Behavioral testing (rotarod, cylinder, gait analysis)
• Intervention arm:
• Olaparib (50mg/kg daily, i.p.)
• Nicotinamide riboside (500mg/kg daily, oral)

Phase 2: Clinical Biomarker Validation (Months 12-36)

Biomarker Cohort Study

• Cohort: 100 early-stage PD (H&Y 1-2), 50 healthy controls
• Samples:
• CSF (8-oxoG, PAR, NAD+)
• Serum (PARP activity, inflammatory markers)
• PBMCs (DNA repair capacity ex vivo)
• Follow-up: Baseline, 6, 12, 24, 36 months
• Endpoints:
• Correlation with MDS-UPDRS progression
• Correlation with DAT-SPECT imaging
• Biomarker predictive value for progression

Inclusion Criteria

Clinical Cohort

• Age 40-75 years
• Diagnosis: PD (UK Brain Bank criteria)
• Hoehn & Yahr stage 1-2
• Disease duration < 5 years
• No DBS or advanced therapy
• No significant cognitive impairment (MoCA > 24)

Exclusion Criteria

• Secondary parkinsonism
• Active infection or inflammatory disease
• Cancer history (5 years)
• DNA repair disorder (Ataxia-telangiectasia, etc.)
• Previous PCR/chemotherapy

Endpoints

Primary

Secondary

Exploratory

Statistical Analysis

• Sample size calculation: Power 80%, α=0.05, effect size 0.5
• Primary analysis: Mixed-effects model for biomarker-disease progression
• Multiple comparisons correction: FDR (Benjamini-Hochberg)
• Machine learning: Random forest for biomarker combination prediction

Budget Estimate

| Item | Cost (USD) |
|------|-------------|
| iPSC differentiation | $150,000 |
| Animal studies | $200,000 |
| Clinical cohort (100 PD, 50 controls) | $350,000 |
| Biomarker assays | $100,000 |
| Personnel (2 FTE × 3 years) | $450,000 |
| Total | $1,250,000 |

Risk Mitigation

| Risk | Mitigation |
|------|------------|
| Insufficient patient recruitment | Multi-center consortium |
| Biomarker variability | Standardized collection protocol |
| PARP inhibitor toxicity | Low-dose escalation design |
| iPSC line variability | Isogenic controls where possible |

Expected Outcomes

Timeline

• Month 1-6: iPSC characterization, assay development
• Month 6-18: Preclinical interventions
• Month 12-24: Clinical cohort enrollment
• Month 24-36: Follow-up completion, analysis
• Month 36: Primary results, publication

Cross-Disease Connections

[DNA damage repair](/mechanisms/dna-damage-repair) deficiency is implicated across [neurodegenerative diseases](/diseases/):

• [Alzheimer's disease](/diseases/alzheimers-disease): [Base excision repair](/mechanisms/dna-damage-repair) decline, increased [8-oxoG](/mechanisms/dna-damage-repair) in [hippocampus](/brain-regions/hippocampus)
• [ALS/FTD](/diseases/amyotrophic-lateral-sclerosis): [TDP-43](/proteins/tardbp) pathology impairs [RNA processing](/mechanisms/nucleocytoplasmic-transport-defects) and [DNA repair](/mechanisms/dna-damage-repair); [C9orf72](/genes/c9orf72) mutations affect [DNA damage response](/mechanisms/dna-damage-repair)
• [Huntington's disease](/diseases/huntingtons): [Poly(ADP-ribose) polymerase](/mechanisms/dna-damage-repair) overactivation consumes [NAD+](/therapeutics/nicotinamide-riboside-nad-booster); [mHTT](/genes/htt) impairs [BER](/mechanisms/dna-damage-repair)
• [Aging](/mechanisms/aging-pathways-neurodegeneration): [NAD+](/therapeutics/nicotinamide-riboside-nad-booster) decline reduces [PARP](/mechanisms/dna-damage-repair) repair capacity — [sirtuin](/mechanisms/sirtuin-signaling-neurodegeneration) dysfunction compounds this

Therapeutic Targets

• [PARP inhibitors](/therapeutics/parp-inhibitors-neurodegeneration): [Olaparib](/therapeutics/parp-inhibitors-neurodegeneration), [rucaparib](/therapeutics/parp-inhibitors-neurodegeneration) — block [NAD+](/therapeutics/nicotinamide-riboside-nad-booster) depletion
• [NAD+ precursors](/therapeutics/nicotinamide-riboside-nad-booster): [Nicotinamide riboside (NR)](/therapeutics/nicotinamide-riboside-nad-booster), [NMN](/therapeutics/nicotinamide-riboside-nad-booster) — restore [sirtuin](/mechanisms/sirtuin-signaling-neurodegeneration) and [PARP](/mechanisms/dna-damage-repair) function
• [8-oxoG repair](/mechanisms/dna-damage-repair): [OGG1](/entities/ogg1) enhancers, [NUDT1](/entities/nudt1) modulators
• [BER enhancers](/mechanisms/dna-damage-repair): Small molecules enhancing [DNA glycosylase](/mechanisms/dna-damage-repair) activity

References

Pathway Diagram

The following diagram shows key molecular relationships for DNA Damage Repair Deficiency Validation Study in Parkinson's Disease based on knowledge graph edges:

Pathway Diagram

The following diagram shows the key molecular relationships involving DNA Damage Repair Deficiency Validation Study in Parkinson's Disease discovered through SciDEX knowledge graph analysis: