This experiment evaluates the efficacy of TREM2 agonistic antibodies in mouse models of Alzheimer's disease, focusing on microglial activation, amyloid clearance, and cognitive outcomes.
Primary Hypothesis: TREM2 agonist treatment will enhance microglial phagocytic activity, reduce amyloid plaque burden, and improve cognitive function in 5xFAD mice.
Secondary Hypothesis: Early intervention (pre-symptomatic) will show greater benefit than late intervention (symptomatic).
TREM2 (Triggering Receptor Expressed on Myeloid Cells 2) is a receptor on microglia that plays a critical role in amyloid clearance. Rare variants in TREM2 increase Alzheimer's disease risk by 3-5x. TREM2 agonism represents a promising therapeutic approach, but optimal dosing and timing remain unknown.
Key questions to address:
- What is the optimal dosing regimen for TREM2 agonists?
- Does timing of intervention affect outcomes?
- What are the downstream effects on the microglial landscape?
- Primary: 5xFAD mice (Jackson Labs, strain #006554)
- Control: Wild-type C57BL/6J littermates
- Intervention Timing:
- Early treatment: 3-month-old (pre-symptomatic)
- Late treatment: 9-month-old (symptomatic)
- Groups (n=25 per group):
- Vehicle control
- TREM2 agonist (10 mg/kg)
- TREM2 agonist (30 mg/kg)
- Late intervention control
- Late intervention treatment
- Antibody administered via intraperitoneal injection
- Twice-weekly treatments for 12 weeks
- Longitudinal CSF sampling at weeks 0, 4, 8, 12
- Cognitive testing at weeks 6 and 12
- Terminal analysis at week 12
- Primary:
- Amyloid plaque burden (Thioflavin S, 6E10 immunohistochemistry)
- Microglial coverage of plaques (Iba1 + 6E10 confocal)
- Secondary:
- Cognitive function (Morris water maze, Y-maze)
- CSF Aβ40/Aβ42 levels (ELISA)
- Gene expression profiling (RNA-seq of sorted microglia)
- Cytokine array (IL-1β, TNF-α, IL-6, IL-10)
¶ Reagents and Equipment
| Item |
Supplier |
Cost (USD) |
| TREM2 agonist antibody (clone 178.1) |
BioLegend |
$15,000 |
| 6E10 antibody |
BioLegend |
$800 |
| Thioflavin S |
Sigma |
$200 |
| Iba1 antibody |
Wako |
$350 |
| Aβ40/42 ELISA kits |
Wako |
$3,500 |
| Flow cytometer |
BD Biosciences |
$150/hour |
| RNA-seq library prep |
Illumina |
$8,000 |
| Confocal microscope |
Zeiss |
$200/hour |
Estimated Total Cost: $120,000
- Washington University — Dr. David Holtzman's group (TREM2 biology)
- Genentech — Dr. Morgan Sheng's group (microglial biology)
- UCLA — Dr. Malcolm Donahue's group (in vivo imaging)
- German Center for Neurodegenerative Diseases (DZNE) — Dr. Christian Haass's group (TREM2 structure/function)
- Months 1-2: Animal colony setup, antibody production/ordering
- Months 3-5: Treatment phase with longitudinal sampling
- Months 6-7: Terminal endpoint and tissue processing
- Months 8-9: RNA-seq, data analysis
- Month 10: Manuscript preparation
Total Duration: 10 months
- 30-50% reduction in amyloid plaque burden at high dose
- 2-fold increase in plaque-associated microglia coverage
- Dose-dependent response curve established
- Improved spatial memory in Morris water maze
- 20-40% reduction in CSF Aβ42
- Distinct microglial transcriptomic signature in treated vs. control
- Clear benefit for early vs. late intervention
- Regular health monitoring
- Pre-specified endpoints to minimize animal usage
- Statistical power analysis: n=25 per group for 80% power to detect 30% effect
| Dimension |
Score (1-10) |
Rationale |
| Scientific Value |
10 |
Addresses fundamental mechanism of microglial function in AD |
| Feasibility |
8 |
Established models and antibodies available |
| Novelty |
9 |
First comprehensive in vivo TREM2 agonist study |
| Disease Impact |
10 |
Direct path to clinical translation |
| Reach |
7 |
Primarily AD, but implications for other neurodegenerative diseases |
| Cost Efficiency |
7 |
Moderate cost for comprehensive mechanistic study |
| Time Efficiency |
8 |
10-month timeline |
| Evidence Base |
9 |
Strong genetic and preclinical data |
| Addresses Uncertainty |
10 |
Resolves key questions about TREM2 therapeutic potential |
| Translation Potential |
10 |
Direct relevance to clinical development programs |
Total Score: 88 × weight normalization = 88/120