• Amyloid precursor protein (APP) is a 100-140 kDa transmembrane glycoprotein closely associated with Alzheimer's disease (AD) pathogenesis.
• Aberrant cleavage of APP by β-secretase and γ-secretase generates amyloid β peptides, including Aβ40 and Aβ42, which can oligomerize, aggregate, and form neurotoxic plaques.
• B-hAPP*K670N*M671L*V717I mice carry human APP sequence with Swedish (K670N, M671L) and London (V717I) familial AD mutations inserted into the endogenous mouse App locus.
• B-hAPP*K670N*M671L*V717I mice express human APP mRNA and human APP protein in disease-relevant CNS tissues, including cortex, hippocampus, cerebellum, and spinal cord.
• This model supports pharmacodynamic, safety, and in vivo efficacy evaluation of human APP-targeted nucleic acid drugs and other Alzheimer's disease therapeutic strategies.

Key Advantages

• Endogenous App locus insertion of human APP with Swedish and London mutations
• Human APP mRNA and protein expression validated in CNS tissues
• Male and female expression data support sex-based study design
• Supports in vivo evaluation of human APP-targeted nucleic acid therapeutics

Validation

• Molecular Validation: Human APP mRNA was detected in homozygous B-hAPP*K670N*M671L*V717I mice by RT-PCR, while mouse App mRNA was detected in wild-type C57BL/6JNifdc mice.
• Protein Validation: Human APP protein was detected in brain tissue, including cortex, hippocampus, cerebellum, and spinal cord, using species-specific anti-APP antibody.
• Sex Comparison Validation: Human APP protein expression was compared between male and female homozygous B-hAPP*K670N*M671L*V717I mice, with no significant difference observed.
• Efficacy Validation: ALN-APP analog reduced human APP mRNA in hippocampus, cortex, and spinal cord after ICV administration in B-hAPP*K670N*M671L*V717I mice.

Application

• Alzheimer's disease pharmacodynamics and safety evaluation
• Human APP-targeted nucleic acid therapeutics studies
• APP mRNA knockdown efficacy studies
• CNS tissue expression and biomarker analysis
• Swedish and London APP mutation model research
• Preclinical evaluation of AD therapeutics targeting APP biology

In B-hAPP*K670N*M671L*V717I mice, a chimeric CDS encoding the human APP signal peptide and extracellular domain with Swedish mutations (K670N, M671L) and London mutation (V717I), followed by human 3' UTR-STOP, was inserted after the mouse App 5' UTR to replace exon 1 of the mouse App gene.
This targeting strategy drives APP expression under the endogenous mouse App promoter while disrupting endogenous mouse App transcription and translation. B-hAPP*K670N*M671L*V717I mice provide a human APP mutant model for Alzheimer's disease drug development and human APP-targeted nucleic acid therapeutics evaluation.

Strain-specific analysis of APP mRNA expression was performed in wild-type C57BL/6JNifdc mice and homozygous B-hAPP*K670N*M671L*V717I mice by RT-PCR.
Cortex RNA was isolated from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hAPP*K670N*M671L*V717I mice (H/H). cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse- or human-specific APP primers. Mouse App mRNA was detected in wild-type mice, and human APP mRNA was detected in homozygous B-hAPP*K670N*M671L*V717I mice.

Western blot analysis of human APP protein expression was performed in homozygous B-hAPP*K670N*M671L*V717I mice.
Various tissue lysates were collected from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hAPP*K670N*M671L*V717I mice (H/H), then analyzed by western blot using species-specific anti-APP antibody (Abcam, ab133588). A total of 50 μg protein was loaded for western blot analysis. Human APP was detected in brain tissue from homozygous B-hAPP*K670N*M671L*V717I mice.

Western blot analysis of human APP protein expression in disease-relevant brain regions.
Tissue lysates were collected from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hAPP*K670N*M671L*V717I mice (H/H), then analyzed with species-specific anti-APP antibody (Abcam, ab133588). A total of 50 μg protein was loaded for western blot analysis. Human APP was detected in cortex, hippocampus, and cerebellum from homozygous B-hAPP*K670N*M671L*V717I mice.

Western blot analysis of human APP protein expression between male and female B-hAPP*K670N*M671L*V717I mice.
Various tissue lysates were collected from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hAPP*K670N*M671L*V717I mice (H/H), then analyzed with species-specific anti-APP antibody (Abcam, ab133588). A total of 40 μg protein was loaded. Human APP was detected in cortex, hippocampus, and spinal cord, and no significant difference was observed between female and male homozygous mice. M, Male; F, Female.

The inhibitory efficiency of ALN-APP analog against human APP was evaluated in B-hAPP*K670N*M671L*V717I mice.
B-hAPP*K670N*M671L*V717I mice were randomly divided into two groups (n=4/group, 10-week-old males). ALN-APP analog (provided by client) and vehicle were administered by intracerebroventricular injection (ICV). Mice were sacrificed on day 7, day 14, and day 28, and hippocampus, cortex, and spinal cord tissues were collected for qRT-PCR detection of human APP mRNA. Human APP mRNA was significantly reduced in the treatment group compared with the vehicle control group. Values are expressed as mean ± SEM. Significance was determined by unpaired t test. ***P < 0.001.
This experiment was conducted in collaboration with the client using B-hAPP*K670N*M671L*V717I mice.

Q1: What are B-hAPP*K670N*M671L*V717I mice?

B-hAPP*K670N*M671L*V717I mice are target-humanized mice carrying human APP with Swedish (K670N, M671L) and London (V717I) familial Alzheimer's disease mutations in the endogenous mouse App locus.

Q2: Why are Swedish and London APP mutations important?

These familial AD mutations affect APP processing and amyloid β generation, making them useful for modeling APP-driven Alzheimer's disease biology and therapeutic intervention.

Q3: How was APP expression validated in this model?

Human APP mRNA was validated by RT-PCR in cortex, and human APP protein was validated by western blot in brain regions including cortex, hippocampus, cerebellum, and spinal cord.

Q4: Can B-hAPP*K670N*M671L*V717I mice be used for nucleic acid drug evaluation?

Yes. ALN-APP analog reduced human APP mRNA in hippocampus, cortex, and spinal cord after ICV administration, supporting evaluation of human APP-targeted nucleic acid therapeutics.

Q5: What are the main applications of this model?

Applications include Alzheimer's disease pharmacodynamics, human APP-targeted drug efficacy, APP mRNA knockdown studies, CNS biomarker research, and preclinical safety evaluation.