Species: Mouse
Genes: Apoe, APP, PSEN1
Mutations: APOE R154S (Christchurch), APP K670_M671delinsNL (Swedish), APP I716V (Florida), APP V717I (London), PSEN1 M146L (A>C), PSEN1 L286V
Modification: Apoe: Knock-In; APP: Transgenic; PSEN1: Transgenic
Disease Relevance: Alzheimer's Disease
Strain Name: N/A
Genetic Background: C57BL/6J
Availability: ApoeCh mice are available for pre-order from The Jackson Laboratory, Stock #039301. Estimated to begin distribution March, 2026. 5xFAD mice are available from The Jackson Laboratory, Stock #034848.
RRID: IMSR_JAX:039301; MMRRC_034848-JAX

Summary

In order to study the effects of the Christchurch mutation in the context of amyloid pathology, ApoeCh mice were crossed with 5xFAD mice (Tran et al., 2025). ApoeCh mice have the Christchurch mutation knocked into the mouse Apoe gene, preserving the species match between the ApoE protein and its murine receptors. 5xFAD mice carry human APP and PSEN1 transgenes with a total of five mutations linked to Alzheimer’s disease. The Christchurch mutation appeared to promote a disease-associated state in microglia surrounding amyloid plaques, accompanied by reductions in plaque load and plaque-associated neuron damage.

ApoeCh and 5xFAD mice were intercrossed to generate the following four genotypes: (i) wild-type (WT), (ii) homozygous for the Apoe Christchurch allele (ApoeCh), (iii) hemizygous for the 5xFAD APP and PSEN1 transgenes (5xFAD) and (iv) homozygous for the Apoe Christchurch allele and hemizygous for the APP and PSEN1 transgenes (5xFAD;ApoeCh). Mice were studied at 4 and 12 months of age. Both males and females were used in these studies; sex-dependent differences were found on several measures, and readers are referred to the original study for details.

Expression of Apoe mRNA and ApoE protein

The Christchurch mutation did not lead to changes in the levels of Apoe mRNA or ApoE protein, compared with wild-type Apoe, as determined by spatial transcriptomics and spatial proteomics, respectively. However, the 5xFAD transgenes led to elevations in Apoe mRNA and ApoE protein.

Increased levels of ApoE protein in transgene carriers were confirmed by ELISA.

Dot blot analysis of detergent-insoluble fractions showed higher levels of ApoE in 5xFAD mice compared with wild-type mice, but no differences between 5xFAD;ApoeCh and ApoeCh.

Peripheral phenotypes

At 4 months of age, average body weight did not differ between mice of the four genotypes. At 12 months, 5xFAD mice were slightly heavier than 5xFAD;ApoeCh mice.

Amyloid pathology

Dense-core plaques were labeled with the AmyloGlo stain and quantified throughout the brains of 5xFAD and 5xFAD;ApoeCh mice. 5xFAD mice homozygous for the Christchurch mutation had fewer plaques and lower plaque burdens (percent area occupied by plaques) than 5xFAD mice homozygous for wild-type Apoe, at both 4 and 12 months. (Mice without the 5xFAD transgenes did not deposit amyloid plaques.)

In addition, the levels of Aβ40 and Aβ42 were measured in cortical and hippocampal extracts. In 4-month-old animals, levels of Aβ40 and Aβ42 in the hippocampus were elevated in both the detergent- soluble and insoluble fractions of 5xFAD;ApoeCh mice, compared with 5xFAD. No genotype-dependent differences in Aβ levels were seen in the cortex. At 12 months, 5xFAD;ApoeCh mice had higher levels of soluble Aβ40 in the cortex and hippocampus than did 5xFAD mice. There were no genotype-dependent differences in levels of soluble Aβ42 or levels of insoluble Aβ40 or Aβ42 in either region.

Neuronal damage

The Christchurch variant protected against two indicators of neuronal damage—plaque-associated neuritic dystrophies and plasma neurofilament light chain (NfL).

Immunostaining for lysosomal-associated membrane protein 1 (LAMP1), which accumulates in dystrophic neurites, was reduced in the subiculum of 5xFAD;ApoeCh, compared with 5xFAD, at both 4 and 12 months of age.

In mice at both ages, levels of plasma NfL were elevated in carriers of the 5xFAD transgenes compared with non-carriers. The Christchurch variant partially protected against this increase in 5xFAD carriers  (i.e., levels of NfL in 5xFAD;ApoeCh plasma were less than levels in 5xFAD plasma).

Gliosis

Initial assessments of gliosis using immunostaining for the astroglial marker glial fibrillary acidic protein (GFAP) and the microglial marker Ionized calcium binding adaptor molecule 1 (Iba1) confirmed gliosis in mice carrying the 5xFAD transgenes and suggested partial protection in mice carrying the Christchurch variant. Subsequent transcriptomic analyses painted a more nuanced picture—with 5xFAD;ApoeCh mice having a greater proportion of glial cells with "disease-associated" transcriptomic profiles than 5xFAD mice with wild-type Apoe.

At 4 and 12 months, astrocyte volume in the subiculum—assessed as the volume of GFAP immunoreactivity—was elevated in carriers of the 5xFAD transgenes compared with non-carriers (5xFAD > WT; 5xFAD;ApoeCh > ApoeCh), and the Christchurch variant partially counteracted this increase (5xFAD > 5xFAD;ApoeCh). At 4 months, the protective effect of the Christchurch variant on astrogliosis in 5xFAD mice was seen in females; while at 12 months, both sexes showed this effect of genotype. It should be noted that the increase in GFAP volume in the subiculum could be due to astrocyte hypertrophy, an increased number of astrocytes, or both (astrocyte numbers were not quantified in this immunohistochemical study).

Spatial proteomic analysis of hemi-brain sections from 14-month-old males showed an increased proportion of GFAP-positive astrocytes in the brains of carriers of the 5xFAD transgenes, compared with non-carriers, but no difference in the proportion of GFAP-positive astrocytes in 5xFAD;ApoeCh compared with 5xFAD.

Spatial transcriptomics—performed on the same brains as the spatial proteomic analysis—revealed an increased proportion of cells classified as disease-associated astrocytes (DAAs) based on their transcriptomic profiles in carriers of the 5xFAD transgenes compared with non-carriers. The proportion of DAAs in 5xFAD;ApoeCh brains was approximately twice that in 5xFAD brains. The proportion of cells classified as homeostatic astrocytes did not differ among the four genotypes.

Microglial volume (volume of Iba1 immunoreactivity) and microglial numbers (number of Iba1-immunoreactive cells) were elevated in the subiculum of mice carrying 5xFAD transgenes compared with non-carriers (5xFAD > WT; 5xFAD;ApoeCh > ApoeCh), at both 4 and 12 months. The Christchurch mutation partially protected against microgliosis in the older mice (5xFAD > 5xFAD;ApoeCh).

Spatial transcriptomics revealed the presence of disease-associated microglia (DAMs) in mice carrying 5xFAD transgenes. As with astrocytes, the proportion of DAMs was greater in 5xFAD;ApoeCh brains than 5xFAD, and the proportion of microglia classified as homeostatic did not differ among the four genotypes. Spatial proteomic analysis confirmed the finding of more DAMs in 5xFAD;ApoeCh than 5xFAD.

Synaptic markers

Thus far, no clear picture has emerged regarding possible effects of the Christchurch mutation on synaptic structure or function. Spatial transcriptomic analysis of brains from 14-month-old male mice suggested an effect of the Christchurch variant on the expression of genes involved in synaptic function and plasticity in CA1, regardless of the presence of the 5xFAD transgenes. However, no differences in synapse number were observed among the four genotypes, as assessed by the co-localization of the pre-synaptic marker Bassoon and the post-synaptic marker Homer1 imaged with super-resolution microscopy.

Behavior

When tested at 4 and 12 months of age, the four genotypes did not differ with regards to time spent in the center of the open field, thought to be a measure of anxiety. There was no difference between  genotypes at 4 months on another measure believed to reflect anxiety—time spent in the open arms of the elevated plus maze (although this interpretation has been challenged [Flanigan et al., 2014]). At 12 months, 5xFAD and 5xFAD;ApoeCh mice spent more time in the open arms, compared with wild-type and ApoeCh mice, respectively, suggesting that the 5xFAD transgenes had an anxiolytic effect. There was no effect of the Christchurch mutation: ApoeCh did not differ from WT and 5xFAD;ApoeCh did not differ from 5xFAD.

Modification details

ApoeCh: CRISPR/Cas9 editing was used to introduce a CGG to TCT missense mutation in the mouse Apoe gene, leading to an arginine-to-serine substitution at amino acid 146 (numbering scheme including the signal peptide) in the mouse ApoE protein—equivalent to amino acid 154 in human ApoE.

5xFAD: These transgenic mice were made by co-injecting two vectors encoding APP (with Swedish [K670N/M671L], Florida [I716V], and London [V717I] mutations) and PSEN1 (with M146L and L286V mutations), each driven by the mouse Thy1 promoter. Mice on the original hybrid B6SJL background were backcrossed to C57BL6 mice for at least five generations.

Related Models

ApoeCh. In the ApoeCh mouse, the Christchurch mutation was introduced into the mouse Apoe gene, preserving the species match between the ApoE protein and its murine receptors (Tran et al., 2025). Thus far, only peripheral phenotypes have been described. At 4 months of age, levels of plasma cholesterol were elevated in homozygous ApoeCh mice compared with wild-type mice, and this effect was primarily driven by males. Levels of plasma triglyceride and very low-density lipid did not differ between the genotypes.

ApoeCh x PS19. In order to study the effects of the Christchurch mutation in the context of tau pathology, ApoeCh mice were crossed with PS19 mice (Tran et al., 2025). In this tauopathy model, the Christchurch mutation promoted a homeostatic state in microglia and counteracted tau-induced changes in gene expression in oligodendrocytes, without decreasing—and, in some cases, exacerbating—certain disease-associated post-translational modifications of tau.

APOE3Ch (Cornell). APOE3Ch (Cornell) mice express human APOE3 with the Christchurch mutation, under the control of mouse regulatory elements (Naguib et al., 2025). Levels of microglial, astrocytic, oligodendroglial, and synaptic markers and network activity were comparable in APOE3Ch (Cornell) mice and knock-in mice expressing wild-type human APOE3.

APOE3Ch (Cornell) x PS19. To study the effects of the Christchurch mutation on tau pathology, APOE3 knock-in mice with or without the Christchurch mutation were intercrossed with PS19 mice, which carry a human MAPT transgene with the P301S mutation linked to frontotemporal dementia (Naguib et al., 2025). The crosses generated mice homozygous for the humanized APOE alleles and hemizygous for the MAPT-P301S transgene. The Christchurch mutation decreased tau pathology and blunted tau-induced losses of synaptic and myelin markers, alterations in network activity, and microglial interferon responses.

APOE3Ch knock-in, floxed (CureAlz). In these knock-in mice, the coding region of the mouse Apoe gene was replaced with the human APOE3 sequence containing the Christchurch mutation. Expression of the humanized gene is under the control of endogenous mouse regulatory elements (Chen et al., 2024). Peripheral dyslipidemia has been reported. Bone marrow-derived macrophages (BMDMs) from mice homozygous for the human APOE3-Christchurch allele show enhanced uptake of tau fibrils, degrade these fibrils more quickly, and release less tau than BMDMs from knock-in mice homozygous for the wild-type human APOE3 allele. Under basal conditions, APOE3Ch and APOE3 BMDMs did not differ in their uptake of Aβ fibrils, but tau fibrils enhanced the uptake of Aβ by APOE3Ch BMDMs, while having no effect on Aβ uptake by APOE3 BMDMs.

APOE3Ch knock-in, floxed (CureAlz), tau intracerebral injection. To study the effects of the Christchurch mutation on tau seeding and spreading, tau fibrils from an AD brain were injected into the brains of APOE3Ch mice or knock-in mice homozygous for the wild-type human APOE3 allele. The Christchurch mutation had little noticeable effect on the propagation of tau pathology but appeared to heighten microglial responses (Chen et al., 2024).

APOE3Ch knock-in, floxed (CureAlz) x APPPS1. To study the effects of the APOE Christchurch mutation in the context of amyloidosis, knock-in mice homozygous for the human APOE3 allele with or without the mutation were intercrossed with APPPS1 mice, which carry transgenes for human APP and PSEN1 with AD-linked mutations. Compared with mice expressing wild-type APOE3, mice with the Christchurch mutation displayed slight reductions in amyloid pathology but increased microglial clustering and microglial reactivity around plaques (Chen et al., 2024).

APOE3Ch knock-in, floxed (CureAlz) x APPPS1, tau intracerebral injection. To study the effects of the APOE Christchurch mutation on tau seeding and spreading in the context of amyloidosis, tau fibrils from an AD brain were injected into the brains of mice with humanized APOE3 genes with or without the mutation, in which amyloid deposition was driven by APP and PSEN1 transgenes with AD-linked mutations (Chen et al., 2024). The APOE Christchurch mutation partially protected against the induction and spread of plaque-associated tau pathology and neuronal damage. The Christchurch mutation also attenuated amyloid pathology in the brains of mice who had received intracerebral injections of tau fibrils, while enhancing microgliosis in the vicinity of fibrillar plaques.

APOE4Ch knock-in, floxed (Gladstone). In these knock-in mice, the coding region of the mouse Apoe gene was replaced with the human APOE4 sequence flanked by LoxP sites and containing the Christchurch mutation (Nelson et al., 2023). Expression of the humanized gene is under the control of endogenous mouse regulatory elements.

APOE4Ch knock-in, floxed (Gladstone) x PS19. To study the effects of the Christchurch mutation on tau pathology in the context of APOE4, APOE4 knock-in mice with or without the Christchurch mutation were intercrossed with PS19 mice, which carry a human MAPT transgene with the P301S mutation linked to frontotemporal dementia (Nelson et al., 2023). Compared with APOE3, APOE4 exacerbated pathology in PS19 mice—increasing levels of “pathological” tau, decreasing hippocampal volume, and increasing gliosis. The Christchurch mutation, when homozygous, fully protected against these effects of APOE4 and showed a gene-dose-dependent effect on proportions of populations of neural cells identified through transcriptomic analyses—increasing disease-protective neuronal and glial subpopulations and decreasing disease-associated glial subpopulations.

Phenotype Characterization

COMMENTS / QUESTIONS

No Available Comments

Make a comment or submit a question

To make a comment you must login or register.

References

Research Models Citations

1. ApoeCh
2. 5xFAD (C57BL6)
3. ApoeCh x PS19
4. Tau P301S (Line PS19)
5. APOE3Ch (Cornell)
6. APOE3 knock-in (Cornell)
7. APOE3Ch (Cornell) x PS19
8. APOE3Ch knock-in, floxed (CureAlz)
9. APOE3 Knock-In, floxed (CureAlz)
10. APOE3Ch knock-in, floxed (CureAlz), tau intracerebral injection
11. APOE3Ch knock-in, floxed (CureAlz) x APPPS1
12. APPPS1
13. APOE3Ch knock-in, floxed (CureAlz) x APPPS1, tau intracerebral injection
14. APOE4Ch knock-in, floxed (Gladstone)
15. APOE4Ch knock-in, floxed (Gladstone) x PS19
16. APOE4 knock-in, floxed (Gladstone)

Mutations Citations

1. MAPT P301S

Paper Citations

1. Tran KM, Kwang NE, Butler CA, Gomez-Arboledas A, Kawauchi S, Mar C, Chao D, Barahona RA, Da Cunha C, Tsourmas KI, Shi Z, Wang S, Collins S, Walker A, Shi KX, Alcantara JA, Neumann J, Duong DM, Seyfried NT, Tenner AJ, LaFerla FM, Hohsfield LA, Swarup V, MacGregor GR, Green KN. APOE Christchurch enhances a disease-associated microglial response to plaque but suppresses response to tau pathology. Mol Neurodegener. 2025 Jan 22;20(1):9. PubMed.
2. Flanigan TJ, Xue Y, Kishan Rao S, Dhanushkodi A, McDonald MP. Abnormal vibrissa-related behavior and loss of barrel field inhibitory neurons in 5xFAD transgenics. Genes Brain Behav. 2014 Mar 21; PubMed.
3. Naguib S, Lopez-Lee C, Torres ER, Lee SI, Zhu J, Zhu D, Ye P, Norman K, Zhao M, Wong MY, Ambaw YA, Muñoz-Castañeda R, Wang W, Patel T, Bhagwat M, Norinsky R, Mok SA, Walther TC, Farese RV Jr, Luo W, Sinha SC, Wu Z, Fan L, Gong S, Gan L. The R136S mutation in the APOE3 gene confers resilience against tau pathology via inhibition of the cGAS-STING-IFN pathway. Immunity. 2025 Jun 18; Epub 2025 Jun 18 PubMed.
4. Chen Y, Song S, Parhizkar S, Lord J, Zhu Y, Strickland MR, Wang C, Park J, Tabor GT, Jiang H, Li K, Davis AA, Yuede CM, Colonna M, Ulrich JD, Holtzman DM. APOE3ch alters microglial response and suppresses Aβ-induced tau seeding and spread. Cell. 2024 Jan 18;187(2):428-445.e20. Epub 2023 Dec 11 PubMed.
5. Nelson MR, Liu P, Agrawal A, Yip O, Blumenfeld J, Traglia M, Kim MJ, Koutsodendris N, Rao A, Grone B, Hao Y, Yoon SY, Xu Q, De Leon S, Choenyi T, Thomas R, Lopera F, Quiroz YT, Arboleda-Velasquez JF, Reiman EM, Mahley RW, Huang Y. The APOE-R136S mutation protects against APOE4-driven Tau pathology, neurodegeneration and neuroinflammation. Nat Neurosci. 2023 Dec;26(12):2104-2121. Epub 2023 Nov 13 PubMed.

External Citations

1. The Jackson Laboratory, Stock #039301
2. The Jackson Laboratory, Stock #034848

Further Reading

No Available Further Reading