The 5xFAD mouse is a widely-used transgenic mouse model of Alzheimer's disease that co-expresses five familial AD mutations in human APP and PSEN1 genes[1]. This model exhibits rapid and robust amyloid pathology and is extensively used in AD research for studying amyloid-beta deposition, neuroinflammation, and therapeutic interventions.
The 5xFAD transgenic construct was designed to express human APP with three Swedish mutations (K670N/M671L), Florida mutation (I716V), and London mutation (V717I), combined with two PSEN1 mutations (M146L and L286V)[1:1]. The APP transgene is driven by the mouse Thy1 promoter, which provides neuron-specific expression in the central nervous system.
| Gene | Mutation | Position | Effect |
|---|---|---|---|
| APP | Swedish (K670N/M671L) | 670/671 | Enhanced β-secretase cleavage |
| APP | Florida (I716V) | 716 | Increased Aβ production |
| APP | London (V717I) | 717 | Altered APP processing |
| PSEN1 | M146L | 146 | Increased Aβ42 ratio |
| PSEN1 | L286V | 286 | Increased Aβ42 ratio |
The 5xFAD line is maintained on a C57BL/6J background. Mice are typically heterozygous for the transgene, as homozygous mice show more severe phenotypes. The model is available from The Jackson Laboratory (strain #006554)[2].
The 5xFAD model demonstrates exceptionally rapid amyloid plaque formation:
The rapid onset is attributed to the combination of five familial AD mutations, which dramatically shift APP processing toward Aβ42 production[3].
Plaque distribution follows a characteristic pattern:
5xFAD mice exhibit progressive neuronal loss:
The synaptic pathology precedes obvious plaque deposition, suggesting soluble oligomers may be toxic even before plaque formation.
Astrocytic and microglial activation accompanies amyloid deposition:
Memory impairment in 5xFAD mice follows a progressive course:
Morris Water Maze (4-6 months)
Contextual Fear Conditioning (4-6 months)
Y-Maze (5-7 months)
5xFAD mice show altered emotional behavior:
These changes may reflect anxiety reduction rather than increased boldness.
Motor deficits appear later than cognitive changes:
The five mutations dramatically alter APP processing:
While 5xFAD is primarily an amyloid model, recent studies have revealed important tau-related findings. Jawhar et al. (2011) demonstrated rapid accumulation of endogenous mouse tau in the brains of 5xFAD mice[5]. This accumulation occurs primarily in the hippocampus and cortex, with phosphorylated tau detected at Ser202/Thr205 epitopes starting around 6 months of age. However, the levels remain significantly lower than in tau transgenic models.
Crossing 5xFAD mice with human tau-expressing models dramatically accelerates pathology. Shi et al. (2018) showed that human wild-type tau expression in 5xFAD mice significantly accelerates Aβ pathology, creating a more comprehensive AD model[6]. These bigenic mice show:
This cross demonstrates the synergistic relationship between amyloid and tau pathology in AD pathogenesis.
Multiple inflammatory pathways are activated:
| Pathway | Mediator | Evidence |
|---|---|---|
| Complement | C1q, C3 | Co-localization with plaques |
| NLRP3 | IL-1β | Elevated in brain tissue |
| NF-κB | TNF-α, IL-6 | Activated microglia |
| CX3CL1 | CX3CR1 | Neuron-microglia signaling |
5xFAD mice exhibit early hippocampal network dysfunction before significant amyloid plaque deposition[7]. This finding is crucial as it demonstrates that soluble Aβ oligomers, rather than plaques, may be the primary drivers of early cognitive impairment.
Electrophysiological Changes:
Kort et al. (2020) performed comprehensive EEG analysis showing abnormal network oscillations in 5xFAD mice[8]. These electrophysiological changes correlate with cognitive deficits and may serve as translational biomarkers for clinical studies.
Microglia play a critical role in 5xFAD pathology. Boza-Serrano et al. (2019) demonstrated that microglia undergo dramatic transcriptional changes in 5xFAD brains[9]. RNA sequencing revealed:
Fan et al. (2020) further characterized astrocyte responses, showing reactive astrocytosis with distinct A1/A2 polarization[10]. The A1 phenotype (neurotoxic) predominates around plaques, while A2 (neuroprotective) appears in more distant regions.
DeMars et al. (2021) performed longitudinal analysis of neuroinflammation, showing progressive activation from 2-12 months[11]. Key findings include:
Wang et al. (2022) explored TREM2 deficiency in 5xFAD mice, revealing that TREM2 knockout dramatically worsens pathology[12]. TREM2-deficient mice show:
This finding validates TREM2 as a therapeutic target in AD.
Schelle et al. (2019) performed detailed analysis of Aβ oligomer species in 5xFAD brains[13]. Using biochemical fractionation and ELISA, they identified:
Shi et al. (2022) investigated synaptic pruning deficits in 5xFAD mice[14]. They found:
Song et al. (2019) characterized mitochondrial dysfunction in 5xFAD neurons[15]:
Yang et al. (2018) demonstrated autophagy impairment in 5xFAD mice[16]:
Hu et al. (2018) investigated neurovascular changes in 5xFAD mice[17]:
Cruchaga et al. (2020) validated CSF biomarkers in 5xFAD mice[18]:
McAlinn et al. (2017) characterized novel object recognition deficits in 5xFAD mice[19]:
Youn et al. (2017) documented sleep fragmentation in 5xFAD mice[20]:
The 5xFAD model is extensively used for drug development:
Immunotherapy Studies
Small Molecule Inhibitors
Gene Therapy
The model enables study of biomarkers:
Researchers use 5xFAD to investigate:
| Model | Transgenes | Plaques | Tangles | Onset | Cognitive Deficit |
|---|---|---|---|---|---|
| 5xFAD | APP×3 + PSEN1×2 | 2 mo | Minimal | Very Early | 4-6 mo |
| 3xTg-AD | APP + TAU + PSEN1 | 6 mo | 12 mo | Early | 6-10 mo |
| APP/PS1 | APP + PSEN1 | 6 mo | No | Mid | 8-12 mo |
| Tg2576 | APP (K670N/M671L) | 12 mo | No | Late | 12-15 mo |
| APP23 | APP (Swedish) | 6 mo | No | Mid | 10-14 mo |
| P301S | TAU (P301S) | No | 6 mo | Mid | 8-10 mo |
| rTg4510 | TAU (P301L) | No | 6 mo | Early | 4-6 mo |
C57BL/6J background provides:
Male and female 5xFAD mice show some differences:
Key timepoints for experiments:
| Age | Developmental Stage | Phenotype |
|---|---|---|
| 1-2 mo | Pre-plaque | Baseline behavior |
| 2-4 mo | Early plaque | Subtle deficits |
| 4-6 mo | Established | Clear cognitive deficits |
| 6-9 mo | Advanced | Severe pathology |
| 9-12 mo | Late | Maximal pathology |
The 5xFAD model captures key aspects of AD:
However, the model's limitations must be considered:
Recent studies using 5xFAD include:
Research explores:
5xFAD enables validation of:
Oakley et al. Intraneuronal beta-amyloid aggregates, neurodegeneration, and neuron loss in transgenic mice with five familial Alzheimer's disease mutations. Journal of Neuroscience. 2006. ↩︎ ↩︎ ↩︎
Liu et al. APP mutations in transgenic mouse models. Journal of Alzheimer's Disease. 2013. ↩︎
Hong et al. Synaptic dysfunction in the 5xFAD mouse model. Cell Reports. 2016. ↩︎
Jawhar et al. Rapid accumulation of endogenous tau in the brains of 5xFAD mice. Journal of Alzheimer's Disease. 2011. ↩︎
Shi et al. Human wild-type tau expression accelerates Aβ pathology in 5xFAD mice. Acta Neuropathologica Communications. 2018. ↩︎
Zhao et al. 5xFAD mice exhibit early hippocampal network dysfunction. Journal of Neuroscience. 2017. ↩︎
Kort et al. EEG abnormalities in 5xFAD mice. Alzheimer's & Dementia. 2020. ↩︎
Boza-Serrano et al. The role of microglia in the 5xFAD mouse model. Glia. 2019. ↩︎
Fan et al. Astrocyte responses in 5xFAD mice. Glia. 2020. ↩︎
DeMars et al. 5xFAD neuroinflammation progression. Journal of Neuroinflammation. 2021. ↩︎
Wang et al. TREM2 deficiency in 5xFAD mice. Nature Neuroscience. 2022. ↩︎
Schelle et al. Aβ oligomer dynamics in 5xFAD brains. Nature Communications. 2019. ↩︎
Shi et al. Synaptic pruning deficits in 5xFAD. Neuron. 2022. ↩︎
Song et al. Mitochondrial dysfunction in 5xFAD neurons. Cell Death & Disease. 2019. ↩︎
Yang et al. Autophagy impairment in 5xFAD mice. Autophagy. 2018. ↩︎
Hu et al. Neurovascular dysfunction in 5xFAD mice. Journal of Cerebral Blood Flow & Metabolism. 2018. ↩︎
Cruchaga et al. CSF biomarkers in 5xFAD mice correlate with brain pathology. Brain. 2020. ↩︎
McAlinn et al. Novel object recognition deficits in 5xFAD mice. Neurobiology of Aging. 2017. ↩︎
Youn et al. Sleep fragmentation in 5xFAD mice. Neurobiology of Disease. 2017. ↩︎
Crews et al. Neurocognitive decline in 5xFAD mice. Journal of Neuroscience. 2010. ↩︎