Chaperone-Mediated Autophagy Dysfunction in PD - Experiment Design
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CMA Dysfunction Validation in PD - Experiment Design
Experiment Overview
Study Code: CMA-PD-001
Hypothesis: Chaperone-mediated autophagy dysfunction is an upstream driver of alpha-synuclein aggregation in Parkinson's Disease
Phase: Preclinical + Clinical Translation
Pathway / Mechanism Diagram
graph TD
A["Nutrient Deprivation / Stress"] --> B["AMPK Activation"]
B --> C["ULK1 Complex Activation"]
A --> D["mTORC1 Inhibition"]
D --> C
C --> E["Phagophore Nucleation (VPS34/Beclin-1)"]
E --> F["LC3 Lipidation (LC3-II)"]
F --> G["Autophagosome Formation"]
G --> H["Cargo Recognition (p62/SQSTM1)"]
H --> I["Autophagosome-Lysosome Fusion"]
I --> J["Cargo Degradation"]
J --> K["Amino Acid Recycling"]
K --> L["Cell Survival"]
M["Autophagy Impairment in Aging"] --> N["Aggregate Accumulation"]
N --> O["Tau, Abeta, alpha-Synuclein Buildup"]
O --> P["Neurodegeneration"]
style L fill:#1b5e20,color:#e0e0e0
style P fill:#ef5350,color:#e0e0e0
style G fill:#006494,color:#e0e0e0
Study Design
Phase 1: Basic Research (In vitro)
1.1 LAMP2A Expression in PD Patient Neurons
Objective: Validate reduced LAMP2A in dopaminergic neurons from PD patients
Models:
iPSC-derived dopaminergic neurons from:
PD patients with LRRK2 G2019S mutation (n=3)
PD patients with idiopathic PD (n=3)
Healthy controls (n=3)
...
CMA Dysfunction Validation in PD - Experiment Design
Experiment Overview
Study Code: CMA-PD-001
Hypothesis: Chaperone-mediated autophagy dysfunction is an upstream driver of alpha-synuclein aggregation in Parkinson's Disease
Phase: Preclinical + Clinical Translation
Pathway / Mechanism Diagram
Mermaid diagram (expand to render)
Study Design
Phase 1: Basic Research (In vitro)
1.1 LAMP2A Expression in PD Patient Neurons
Objective: Validate reduced LAMP2A in dopaminergic neurons from PD patients
Models:
iPSC-derived dopaminergic neurons from:
PD patients with LRRK2 G2019S mutation (n=3)
PD patients with idiopathic PD (n=3)
Healthy controls (n=3)
Endpoints:
LAMP2A mRNA and protein levels (qPCR, Western blot)
CMA activity assay (KFERQ-destained reporter)
Co-localization of LAMP2A with lysosomal markers (LAMP1, cathepsin D)
1.2 CMA Inhibition Effect on α-synuclein
Objective: Determine if CMA inhibition promotes α-synuclein aggregation
Models:
SH-SY5Y cells expressing wild-type or mutant α-syn (A53T, A30P)
siRNA-mediated LAMP2A knockdown
Endpoints:
α-synuclein oligomerization (ELISA, native PAGE)
CMA substrate accumulation (c-Flip, MEF2D)
Cell viability (MTT, caspase 3/7)
1.3 LAMP2A Overexpression Protection
Objective: Test if LAMP2A overexpression protects against α-syn toxicity
Models:
SH-SY5Y cells with LAMP2A overexpression + α-syn (WT/A53T) expression
Endpoints:
α-syn aggregation (Thioflavin S, α-syn PSer129)
Mitochondrial function (JC-1, ATP assay)
Autophagy markers (LC3II/I, p62)
Phase 2: Preclinical (In vivo)
2.1 AAV-LAMP2A in α-syn transgenic mice
Objective: Test LAMP2A overexpression in vivo
Models:
Thy1-α-syn transgenic mice (line M83)
AAV9-LAMP2A vs. AAV9-GFP (control)
Treatment:
6-month-old mice
Intracerebral ventricular injection
3-month survival post-treatment
Endpoints:
Motor behavior (rotarod, pole test, cylinder test)
α-syn pathology (pSer129, oligomers)
LAMP2A expression in substantia nigra
Dopaminergic neuron survival (TH+ count)
2.2 CMA activator compound screening
Objective: Identify small molecules that enhance CMA
Primary Screen:
FDA-approved library (2800 compounds)
CMA reporter assay (KFERQ-dsDNA)
Hit criteria: 1.5-fold CMA activation, non-toxic
Secondary Validation:
10 highest-scoring hits
Dose-response in SH-SY5Y cells
Selectivity vs. macroautophagy
Phase 3: Clinical Translation
3.1 Biomarker Study
Objective: Validate CMA activity as PD biomarker
Cohort:
Early PD (n=50, Hoehn-Yahr 1-2)
Prodromal PD (n=25, REM sleep behavior disorder)
Healthy controls (n=50)
Samples:
Peripheral blood mononuclear cells (PBMCs)
CSF (subset, n=30 per group)
Endpoints:
LAMP2A expression in PBMCs (flow cytometry)
CMA activity in fibroblasts (from subset)
α-syn species in CSF (RT-QuIC)
Clinical measures (MDS-UPDRS, MoCA)
3.2 Proof-of-Concept Study
Objective: Test repurposed CMA enhancers
Compound Selection:
Arimoclomol (heat shock protein co-inducer) - 400mg BID
Placebo control
Cohort:
Early PD (n=60, 1:1 randomization)
12-month treatment
Endpoints:
Safety and tolerability
MDS-UPDRS motor subscore
LAMP2A expression (PBMCs)
CSF α-syn (exploratory)
Statistical Analysis
Sample size calculated for 80% power, α=0.05
ANOVA with Tukey post-hoc for multiple comparisons