The 5xFAD mouse model is a rapid-onset transgenic mouse model of Alzheimer's disease that expresses five familial AD (FAD) mutations — three in the APP gene and two in the PSEN1 gene. This model was developed by Oakley et al. in 2006 and is characterized by extremely early and robust amyloid-beta plaque formation, with plaques detectable as early as 2 months of ageoakley2006.
The 5xFAD model is one of the fastest-acting AD mouse models available, making it particularly valuable for therapeutic intervention studies where rapid pathology development is essential.
The 5xFAD model contains five familial AD mutationsoakley2006:
| Gene | Mutation | Promoter | Effect |
|---|---|---|---|
| APP | Swedish (KM670/671NL) | Thy1.2 | Increased Aβ production |
| APP | Florida (I716V) | Thy1.2 | Enhanced Aβ42 production |
| APP | London (V717I) | Thy1.2 | Aβ42 aggregation |
| PSEN1 | M146L | Thy1.2 | γ-secretase alteration |
| PSEN1 | L286V | Thy1.2 | Aβ42 bias |
The three APP mutations work synergistically to drive extreme Aβ production:
The two PSEN1 mutations alter γ-secretase activity:
| Feature | Details |
|---|---|
| Promoter | Thy1.2 (neuron-specific) |
| Expression | Neuronal, CNS-specific |
| Transgenes | 5 FAD mutations (3 APP + 2 PSEN1) |
| Plaque onset | 2 months of age |
| Aβ42 levels | Extremely high |
The 5xFAD model demonstrates the earliest and most robust amyloid plaque formation of any AD mouse model. Plaque formation begins in the subiculum and cortical layer V, then spreads throughout the hippocampus and cortexoakley2006.
A distinctive feature of the 5xFAD model is the accumulation of intraneuronal Aβ42 before plaque formation. This intracellular accumulation appears as early as 1.5 months of age and may be the trigger for subsequent plaque formation and neuronal dysfunction.
| Age | Pathology | Behavior |
|---|---|---|
| 1-2 months | Intraneuronal Aβ42 | Normal |
| 2-4 months | Early plaque formation | Normal to subtle |
| 4-6 months | Dense plaques, gliosis | Mild cognitive changes |
| 6-9 months | Neuronal loss | Clear impairment |
| 9-12 months | Full pathology | Significant decline |
| Advantage | Description |
|---|---|
| Rapid onset | Plaques by 2 months - fastest AD model |
| Aβ42 predominant | Models toxic Aβ42 species |
| Robust pathology | Dense, consistent plaque formation |
| Sex differences | Useful for sex-specific studies |
| Therapeutic screening | Rapid endpoint for drug testing |
| Limitation | Description |
|---|---|
| No tau pathology | Lacks neurofibrillary tangles |
| Non-physiological | Multiple mutations, high expression |
| Sex differences | Can complicate interpretation |
| Translation | Does not replicate human sporadic AD |
| Rapid onset | May not reflect human disease timing |
The 5xFAD model is widely used for:
| Feature | 5xFAD | 3xTG-AD | APP/PS1 | Tg2576 |
|---|---|---|---|---|
| Plaque onset | 2 months | 6 months | 6-9 months | 9-12 months |
| Mutation count | 5 (3 APP + 2 PSEN1) | 3 | 2 | 1 |
| Tau pathology | No | Yes | No | No |
| Neuronal loss | Yes | Yes | Moderate | Minimal |
| Speed | Fastest | Medium | Medium | Slow |
| Research use | Drug screening | Mechanism | Standard | Behavioral |