APP transgenic Mouse Models
Alzheimer’s disease (AD) is one of the most devastating neurodegenerative diseases of the 21st century. A disturbed APP metabolism (e.g. pathological aggregation of amyloid) in the brain of AD patients is thought to be one of the main causes of the observed progressive cognitive decline in affected people. The development of new AD drugs targeting APP related mechanisms is therefore one main focus in AD research. To be able to test these new drugs, appropriate animal models are needed.
QPS Austria currently offers seven human APP transgenic mouse lines featuring different properties with regard to Aβ expression patterns, neuroinflammation, cognitive deficits, age at onset and progression of pathology. These animals focus on different pathological readouts and constitute suitable models to study the influence of drugs on APP-related brain pathology and behavior.
APPSL transgenic Mouse Model
APPSL transgenic mice over-express human APP751SL under the control of the murine Thy-1 promoter. This human APP with London (717) and Swedish (670/671) mutations is expressed in high levels, resulting in an age-dependent increase of beta-amyloid1-40 and beta-amyloid1-42, the pathologically relevant forms of amyloid protein. Starting at 3 – 6 months APPSL mice develop plaques consisting of amyloid depositions in the frontal cortex.
Severity of the brain pathology correlates with increasing age and behavioral deficits. Cognitive deficits of these mice include spatial and emotional learning as well as long term memory deficits (Havas et al., 2011). Additionally, APPSL animals present with severe neuroinflammation and oxidative stress starting as early as 6 and 9 months of age, respectively (Löffler et al., 2014). This model presents with an unchanged motor performance.The modifiability of several of these pathologies was already shown in a whole series of treatment studies (Windisch et al., 2013).
Figure 1: Assessment of spatial learning in the Morris water maze learning curves showing distance traversed and escape latencies during 4 testing days of 6 (A, D), 9 (B, E) and 12-month (C, F) old APPSL (blue) and WT (orange) animals. 6-month old APPSL n=19, WT n=21; 9-month old APPSL n=21, WT n=19; 12-month old APPSL n=13, WT n=22; Statistical analyses: Two-way-ANOVA with Bonferroni‘s post-test compared to WT. *p<0.05; **p<0.01; ***p<0.001.
Figure 2: Qualitative comparison of plaque pathology of APPSL transgenic mice at 3, 6 and 9 months of age. Tissue was labeled with antibody 6E10. Scalebar: 1mm
APPSL x hQC transgenic Mouse Model
QPS holds an exclusive license from Probiodrug AG for APPSL x hQC mice, which are crossbreds of APPSL and hQC mice (Jawhar et al., 2011). Both transgenes are under the regulatory control of the Thy1 promoter and both mouse lines have a pure C57BL/6xDBA background.
The cross breeding of APPSL and hQC mice results in an increased generation of N-terminal modified pGlu Aβ peptides and allows the analysis of neurodegenerative events that depend on specific pGlu Aβ enzymatic activity in vivo. These mice are an efficient model to analyze pGlu Aβ modifying drugs in vivo. Additionally, double transgenic APPSL x hQC mice present with the same pathologies as APPSL mice, like plaque formation, neuroinflammation and cognitive deficits, but most symptoms appear a little earlier as in single transgenic APPSL mice. This model presents with an unchanged motor performance.
APPSL x hQC mice are thus a good tool to study pGlu Aβ-dependent effects on cognition and histological parameters at an early age of 6 months. An additional readout of APPSL x hQC mice are hQC levels.
Escape latency in the Morris water maze of 6 months old APPSL x hQC mice compared to non transgenic littermates and pGlu Aβ levels in the hippocampus of APPSL x hQC mice over age. Data are represented as mean ± SEM. 5.5 months: 8 APPSL x hQC; 7.5 months: 8 APPSL x hQC; 9.5 months: 8 APPSL x hQC; 12.5 months: 8 APPSL x hQC; 22 months: 4 APPSL x hQC. **p<0.01; ***p<0.001.
ApoB x APP transgenic Mouse Model
These mice are crossbreds of APPSL and Apo-B100 mice overexpressing the entire 43 kb human apolipoprotein B-100 gene (ApoB-100; Bjelik et al., 2006) including its natural human promoter. These mice present with all pathological features of APPSL mice and additionally show increased LDL-cholesterol and decreased HDL-cholesterol levels. Cortical oxidative stress starts already at the age of 6 months in double transgenic mice. Additionally, at the same age ApoB x APP mice show a strong accumulation of ApoB100 in cerebral vessels and astrogliosis in the hippocampus. This model presents with an unchanged motor performance.
The ApoB x APP transgenic mouse line is a suitable model for vascular disease dependent amyloidogenic Alzheimer’s disease research, since it illustrates major biochemical and behavioral hallmarks of AD (Löffler et al., 2013).
Additional readouts of ApoB x APP mice are:
• LDL- and HDL- cholesterol levels
• Cerebral accumulation of ApoB-100 in leptomeningeal vessels
Plasma lipid profile of 6 months old ApoB x APP transgenic animals. LDL levels after Friedewald, and HDL levels are shown in percent relative to non-transgenic littermates. A: ApoB x APP; B: ApoB-100; C: APPSL; D: non-transgenic littermates. A: N= 13, B: N=18, C: N=16, D: N=18. *p<0.05; **p<0.01; ***p<0.001. One-Way ANOVA followed by Bonferroni’s multiple comparison test.
5xFAD transgenic Mouse Model
5xFAD (Familiar Alzheimer Disease) mice bear 5 mutations, 3 in the APP695 gene [APP K670N/M671L (Swedish), I716V (Florida), V717I (London)] as well as 2 mutations in the presenilin 1 gene [PS1 M146L, L286V] (Oakley et al., 2006). The expression of the 5xFAD transgene is driven by the neuron specific Thy1 promoter.
5xFAD transgenic mice highly overexpress Aβ1-40 and Aβ1-42 in the brain and cerebrospinal fluid which even increases over age. Histological analyses of the cortex and hippocampus revealed a dramatic plaque load and beta sheet formation accompanied by strong neuroinflammation. These pathological hallmarks also significantly increase over age. Animals present spatial and long term memory deficits as analyzed by the Morris water maze. Motor deficits were not detected.
5xFAD tg mice are thus a suitable model to study the influence of drugs on amyloid production, sequestration and deposition, the involvement of presenilin1 and inflammation.
Aβ plaque load quantification in the cortex and hippocampus of 3 and 9 months old 5xFAD transgenic mice. Number of objects per mm2 in the cortex (left panel) and hippocampus (right panel). N =5. Data are shown as mean ±SEM. Data were analyzed by t-test. ***p<0.001.
TBA2.1 transgenic Mouse Model
The human TBA2.1 transgenic mouse model is suitable to model AD related neuronal loss and neurodegeneration and thus late stage AD. The mice were developed and characterized by Alexandru and colleagues.
This AD transgenic mouse model over-expresses truncated mutated human Aβ(Q3-42) under the control of a neuron specific mThy1.2 promoter with a C57BL/6xDBA1 background. Aβ(Q3-42) is fused to pre-pro-TRH for product release within the secretory pathway (Alexandru et al., 2011). Quantification of pE3-Aβ protein levels show a peak of pE3-Aβ levels at the age of 1 month and afterwards decreasing. Aβ quantification on the other hand, shows a continuous increase of Aβ levels over age (Alexandru et al., 2011). Homozygous TBA2.1 animals further present with a severe neuronal loss in the hippocampal medial CA1 region (Fig.1 and Alexandru et al., 2011), depending on a reduced number of pyramidal cell somata and thus a reduced thickness of the stratum pyramidale (Fig.1, 2 and Alexandru et al., 2011).
Figure 1: Neurodegeneration in 5 months old homozygous and heterozygous TBA2.1 mice. CA1 region size (A). NeuN-immunoreactivity of the CA1 region (B). *p<0.05; **p0.01.
At the age of 3-5 months, astrogliosis and microgliosis as indicator of neuroinflammation are highly increased in homozygous TBA2.1 mice (Fig.2 and Alexandru et al., 2011).
Figure 2: Astrocytosis in 5 months old homozygous TBA2.1 mice. (A) Reduced thickness (arrowheads) of stratum pyramidale (sp). (B) GFAP-positive astrocytes in TBA 2.1 mice. Abbreviations: corpus callosum (cc), strata oriens (so) and radiatum (sr).
Figure 3: Synaptic dysfunction of TBA2.1 mice. LTP of fEPSP after application of strong tetanus at time point 0. (A) LTP of 5 months old homozygous TBA2.1 mice compared to non-transgenic littermates. (B) fEPSP amplitude of 5 months old homozygous TBA2.1 mice compared to non-transgenic littermates. 
Behavioral characterization of homozygous TBA2.1 mice reveals a reduced free feeding and drinking behavior, slowed body weight gain and severely disturbed hanging behavior, righting reflex and motor deficits as analyzed by Rota Rod starting at early age. Furthermore, already 1 month old animals present with a significantly reduced prepulse inhibition of the auditory startle reflex (Alexandru et al., 2011).
Due to the severe neuronal loss and synaptic dysfunction of homozygous TBA2.1 mice, this transgenic mouse model reflects the ideal tool for the study of pE3-Aβ dependent neurodegeneration and the analysis of new compounds against late stage AD. QPS Austria offers custom tailored study design for this model and we are flexible to accommodate to your special interest. We are also happy to advice you and propose study designs. A typical turnaround time from agreement to the study plan and eventually to the final report is about 4 months.
QPS Austria maintains its own colony directly in our research facility. Animals are typically available without any long delay. Compared to other APP transgenic mouse lines, the TBA2.1 line shows relevant features of late stage AD already at young age. This allows for extraordinarily fast turn-around times. Furthermore, heterozygous and non-transgenic littermates are available as control animals needed for proper study design. We would be happy to test your compounds in our Aβ(Q3-42) transgenic mouse model!
The most common readouts are:
- Neuronal loss and neurodegeneration
- Prepulse Inhibition
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Tg4-42 (TBA83) Mouse Model
This AD transgenic mouse model over-expresses N-truncated human Aβ(4-42) under the control of a neuron specific mThy1 promoter with a C57BL/6 J background.
The Tg4-42 (TBA83) mouse model is suitable to model AD related neuronal loss and neurodegeneration and thus late stage AD.
Characterization of Tg4-42 mice by Bouter et al. 2013:
- Strong Aβ42 immunostaining in CA1 in 3 months old hemizyous Tg4-42 mice with an age-dependent reduction in positive cells
- Further Aβ42 positive areas: occipital cortex, piriform cortex, striatum, superior colliculus
- Increased astrogliosis and microgliosis as early as 2 months in hemizygous Tg4-42 mice
- Age and dose dependent neuron loss in the hippocampus of Tg4-42 mice
Characterization by QPS Austria:
- Spatial learning and memory deficits in the Morris water maze
Figure 1: Morris water maze of 12 months old Tg4-42 mice. Escape latency in seconds (left) and abidance in the target sector in percent (right). Mean ± SEM; n=4-10; 2-way ANOVA: *p<0.05, **p<0.01, ***p<0.001.
Figure 2: Aβ42 immunohistochemistry in the hippocampal CA1 region of 3, 8 and 12 months old Tg4-42 mice. Scale bar: 100μm.
Figure 3: Hippocampal neuronal loss in the hippocampal CA1 region of 8 months old Tg4-42 mice. NeuN immunohistochemistry in wildtype (A), hemizygous (B) and homozygous (C) Tg4-42 animals. Scale bar: 100μm. Quantification of neurons (D) in 3, 8 and 12 months old Tg4-42 mice. Mean ± SEM; n=6; 1-Way ANOVA: **p<0.01; ***p<0.001.
Tg2576 Mouse Model
QPS Austria offers custom tailored study designs for these models and we are flexible to customize to your special need. We are also happy to advise you and propose previously successful study designs. A typical turnaround time from agreement to the study plan to the final report is about 4 months. QPS Austria maintains its own colonies directly in our research facility, and animals of all age groups are typically available without any long latency. This allows for extraordinarily fast turn-around times. Non-transgenic control littermates are available as needed for proper study design. We would be happy to test your compounds in our APP transgenic mouse models! The most common readouts are:
- Soluble and insoluble Aβ levels
- Aβ Oligomers
- APP plaques
- Thioflavin S
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Alternative model QPS Austria offers alternative models allowing the performance of similar types of studies like APPSL and 5xFAD transgenic mice or any other commercially available mouse line. You might also be interested in these related topics
- In vitro AD models
- Scopolamine induced AD mouse model
- Amorfix Aggregated Aβ Assay (A4)
- Intracerebral β-amyloid injections in rats
As with all other in vivo models we are also ready to provide samples (brain tissue, CSF etc.) from these animals for analyses in your laboratory. We are happy to receive your inquiry.