Sirtuin Pathway Dysfunction Validation in Parkinson's Disease

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experiment1232 wordssynced 2026-04-02

title: Sirtuin Pathway Dysfunction Validation in Parkinson's Disease
description: Multi-phase study to validate sirtuin pathway dysfunction as disease mechanism and test NAD+ repletion/sirtuin modulation as disease-modifying therapy
published: true
tags: kind:experiment, section:experiments, state:published, parkinson, sirtuin, NAD+, clinical-trial
editor: markdown
dateCreated: "2026-03-28T02:30:00.000Z"
dateUpdated: "2026-03-28T02:30:00.000Z"
refs:
schutz2024:
title: NAD+ metabolism in neurodegenerative diseases
pmid: "31155018"
hades2024:
title: NAD+ repletion rescues mitochondrial function in Parkinson's disease
pmid: "31740891"
tyrrell2023:
title: SIRT1 activity is reduced in PD patient-derived neurons
pmid: "30659479"
chen2019:
title: SIRT2 inhibition protects against alpha-synuclein toxicity
pmid: "24631280"
li2015:
title: SIRT3 overexpression protects dopaminergic neurons
pmid: "25933439"
yang2013:
title: Resveratrol and neuroprotection in PD models
pmid: "23792933"

Sirtuin Pathway Dysfunction Validation in Parkinson's Disease

Relationship to NADAPT Study

...

Sirtuin Pathway Dysfunction Validation in Parkinson's Disease

Relationship to NADAPT Study

Mermaid diagram (expand to render)

This validation protocol is designed to complement and extend the findings from the NADAPT Study (NCT06162013), a Phase 2 clinical trial evaluating NAD+ precursor supplementation in Parkinsonian syndromes. While NADAPT focuses on therapeutic intervention, this study focuses on mechanistic validation of sirtuin pathway dysfunction as the underlying biological mechanism.

Experiment Overview

Experiment ID: SIRTUIN-PD-001 Hypothesis: Sirtuin pathway dysfunction drives dopaminergic neurodegeneration through impaired NAD+-dependent deacetylation, leading to mitochondrial dysfunction, neuroinflammation, and alpha-synuclein aggregation.

Primary Objective: Validate sirtuin pathway dysfunction as a disease mechanism in PD and assess NAD+ repletion and sirtuin modulation as disease-modifying therapeutic strategies.

Study Design: Multi-phase (biomarker → Phase II clinical), aligned with NADAPT framework

Phase 1: Preclinical Validation (12 months)

1.1 In Vitro Studies

A. Human iPSC-Derived Dopaminergic Neurons

Model: iPSCs from PD patients (LRRK2 G2019S, idiopathic) vs. healthy controls
Endpoints:
NAD+ levels (enzymatic assay)
SIRT1, SIRT3 activity (fluorometric kits)
Mitochondrial function (Seahorse XF)
Alpha-synuclein aggregation (pSer129 ELISA)
Cell viability after stress (MTT)
Hypothesis: PD neurons will show reduced NAD+, impaired sirtuin activity, and increased vulnerability to oxidative stress

B. Sirtuin Knockout/Overexpression in Dopaminergic Cells

Cell lines: SH-SY5Y, rat primary dopaminergic neurons
Genetic manipulation:
SIRT1 CRISPR KO vs. overexpression
SIRT3 CRISPR KO vs. overexpression
SIRT2 CRISPR KO
Endpoints:
Mitochondrial parameters (mtDNA copy number, Complex I activity)
Oxidative stress markers (MitoSOX, 4-HNE)
Autophagy flux (LC3-II/LC3-I ratio, p62)
Alpha-synuclein aggregation (Thioflavin-T, pSer129)

1.2 In Vivo Studies

A. MPTP Mouse Model

Animals: C57BL/6 mice (male, 10-12 weeks)
Groups (n=15 per group):

1. Vehicle control

MPTP only (30mg/kg × 5 days)

MPTP + Nicotinamide riboside (NR, 400mg/kg/day, p.o.)

MPTP + SRT2104 (SIRT1 activator, 100mg/kg/day, p.o.)

MPTP + SRT1720 (SIRT3 activator, 50mg/kg/day, p.o.)

MPTP + SIRT2 inhibitor (AGK2, 10mg/kg/day, i.p.)

Duration: 4 weeks post-MPTP
Endpoints:
Behavioral: open field, cylinder test, rotarod
Biochemical: TH+ neuron count in SNc (IHC), striatal dopamine (HPLC)
Molecular: NAD+ levels, sirtuin activity, mitochondrial function
Biomarkers: blood NAD+, CSF NAD+ (in subset)

B. Alpha-Synuclein Preformed Fibril (PFF) Model

Animals: C57BL/6 mice (male, 10-12 weeks)
Groups (n=15 per group):

1. Vehicle + PBS

PFF only

PFF + NR (400mg/kg/day)

PFF + SRT2104 (100mg/kg/day)

Duration: 12 weeks post-PFF
Endpoints:
Behavioral tests
Alpha-synuclein pSer129 pathology (IHC)
Neuroinflammation (Iba1, GFAP IHC)
Mitochondrial function in isolated mitochondria

1.3 Mechanism Elucidation

RNA-seq: SNc from treated vs. control mice (pathway enrichment: mitochondrial biogenesis, autophagy, inflammation)
Proteomics: Mitochondrial and nuclear fractions
Metabolomics: Brain tissue, blood, and CSF (NAD+ metabolome)
Acetyl-proteomics: Global acetylation changes in response to treatment

Phase 2: Clinical Biomarker Study (6 months)

2.1 Cross-Sectional Biomarker Assessment

Cohort: 150 participants

| Group | N | Criteria |
|-------|---|----------|
| PD patients (early, H&Y 1-2) | 70 | Diagnosis <2 years, not on NAD+ supplements |
| PD patients (advanced, H&Y 3-4) | 50 | Disease duration >5 years |
| Healthy controls | 30 | Age-matched, no neurological disease |

Endpoints:

Blood NAD+ Panel:

NAD+ and NADH levels (whole blood, plasma)
NMN, NR, nicotinamide levels
Metabolomics profile

Sirtuin Activity in PBMCs:

SIRT1 deacetylase activity
SIRT3 deacetylase activity
Protein expression (WB)

Mitochondrial Function (in PBMC-derived neutrophils):

Complex I activity
ROS production (MitoSOX)
mtDNA copy number

Clinical Correlation:

MDS-UPDRS parts I-III
MoCA
Levodopa equivalent dose
Disease duration

Phase 3: Clinical Trial (18 months)

3.1 Phase II Trial: NAD+ Repletion in PD

Design: Randomized, double-blind, placebo-controlled

Cohort: 120 participants

| Arm | N | Intervention |
|----|---|--------------|
| Placebo | 40 | Matching placebo |
| Low-dose NR | 40 | NR 500mg BID |
| High-dose NR | 40 | NR 1000mg BID |

Inclusion Criteria:

PD diagnosis <3 years
H&Y 1-2.5
Age 40-75
Not on NAD+ supplements

Endpoints:

Primary:

Change in MDS-UPDRS part III at 12 months
Blood NAD+ levels at 3 months

Secondary:

Change in MDS-UPDRS parts I, II, IV
MoCA score
CSF biomarkers (subset, n=40): NAD+, alpha-synuclein, tau, neurofilament
Safety: adverse events, lab values

Exploratory:

PET imaging: [18F]FDG for brain metabolism
Actigraphy for sleep/activity
Quality of life (PDQ-39)

Biomarker Development

Primary Biomarkers

| Biomarker | Matrix | Assay | Purpose |
|-----------|--------|-------|---------|
| NAD+ | Blood | Enzymatic | Enrollment, response |
| NAD+/NADH ratio | Blood, CSF | HPLC/LC-MS | Disease status |
| NMN | Blood | LC-MS | NAD+ precursor |
| SIRT1 activity | PBMCs | Fluorometric | Target engagement |
| SIRT3 activity | PBMCs | Fluorometric | Target engagement |

Secondary Biomarkers

| Biomarker | Matrix | Assay | Purpose |
|-----------|--------|-------|---------|
| pSer129 α-syn | CSF | ELISA | Target pathway |
| Neurofilament light | CSF | ELISA | Neurodegeneration |
| mtDNA copy number | Blood | qPCR | Mitochondrial health |
| Complex I activity | PBMCs | Enzymatic | Mitochondrial function |

Statistical Analysis

Power Calculations

For Phase II trial (MDS-UPDRS part III):

Effect size: 5 points (SD=10)
Power: 80%, α=0.05 (two-tailed)
Required n: 100 (accounting for 20% dropout)

Analysis Plan

Primary: Mixed-model ANOVA for repeated measures

Biomarker: Correlation (Pearson/Spearman) with clinical outcomes

Timeline

| Phase | Duration | Milestone |
|-------|----------|-----------|
| Phase 1 | 12 months | Preclinical validation complete |
| Phase 2 | 6 months | Biomarker study complete |
| Phase 3 | 18 months | Phase II trial complete |
| Total | 36 months | Full validation |

Budget Estimate

| Item | Cost (USD) |
|------|------------|
| Phase 1 (preclinical) | $800,000 |
| Phase 2 (biomarker) | $400,000 |
| Phase 3 (Phase II trial) | $2,500,000 |
| Regulatory | $300,000 |
| Total | $4,000,000 |

Cross-References

[NADAPT Study (NCT06162013) - NAD Replenishment Therapy](/clinical-trials/nadapt-study-nad-replenishment-parkinsonism-nct06162013) — Parallel Phase 2 clinical trial
[Sirtuin Pathway Dysfunction Hypothesis](/hypotheses/sirtuin-pathway-dysfunction-parkinsons) — Theoretical framework
[NAD+ Metabolism Pathway](/mechanisms/nad-metabolism-pathway-neurodegeneration) — Metabolic basis
[SIRT1 Gene](/genes/sirt1) — Master regulator, PGC-1α/FOXO3a
[SIRT2 Gene](/genes/sirt2) — Cytosolic, α-tubulin/α-synuclein
[SIRT3 Gene](/genes/sirt3) — Mitochondrial, MnSOD/Complex I
[NAD+ Precursors in Neurodegeneration](/therapeutics/nad-precursors-neurodegeneration) — Therapeutic approach
[Sirtuin Modulators](/therapeutics/sirtuin-modulators) — Drug candidates

References

[NAD+ metabolism in neurodegenerative diseases (2019)](https://pubmed.ncbi.nlm.nih.gov/31155018/)

[NAD+ repletion rescues mitochondrial function in PD (2019)](https://pubmed.ncbi.nlm.nih.gov/31740891/)

[SIRT1 activity is reduced in PD patient-derived neurons (2018)](https://pubmed.ncbi.nlm.nih.gov/30659479/)

[SIRT2 inhibition protects against α-synuclein toxicity (2014)](https://pubmed.ncbi.nlm.nih.gov/24631280/)

[SIRT3 overexpression protects dopaminergic neurons (2015)](https://pubmed.ncbi.nlm.nih.gov/25933439/)

[Resveratrol and neuroprotection in PD models (2013)](https://pubmed.ncbi.nlm.nih.gov/23792933/)

[SIRT1 genetic variants and PD risk (2019)](https://pubmed.ncbi.nlm.nih.gov/29550616/)

[NCT06162013 - The NADAPT Study](https://clinicaltrials.gov/study/NCT06162013)

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