APOE4 to APOE2 allelic switching in mice improves Alzheimer’s disease-related metabolic signatures, neuropathology and cognition

In the paper

“E2-TR mice display a plasma lipid profile similar to the type III hyperlipoproteinemia found in ~5–10% of E2/E2 humans, particularly when challenged with a high-fat diet (HFD)20.”

What the sources say

• Supported

  The Introduction states that 5–10% of human apoE2 homozygotes develop type III hyperlipoproteinemia. The Discussion says the 2/2 mice have virtually all its characteristic lipid features and that high-fat, high-cholesterol diets exacerbate their hyperlipoproteinemia. (LLM, conf=0.94)

  cites [20] Sullivan, P., Mezdour, H., Quarfordt, S. & Maeda, N. Type III hyperlipoproteinemia and spontaneous atherosclerosis in mice resulting from gene replacement of mouse Apoe with human Apoe*2. J. Clin. Invest. 102, 130–135 (1998). source

In the paper

“Finally, the DEGs associated with the E4 to E2 switch also strongly reflected several APOE-associated and AD-associated gene lists, particularly the late-onset AD (LOAD) genes identified in and merged from publicly available human transcriptomic datasets (Fig. 3i)25–28.”

What the sources say

• Supported

  The Abstract (p. 1, Methods) says the authors merged five publicly available human AD transcriptomic profiles and analyzed differential expression; it identifies LOAD as one of the patient groups compared. This supports citing the paper as a source of the LOAD gene list. The E4-to-E2 overlap is the citing authors’ comparison, not a finding attributed to this source. (LLM, conf=0.88)

  cites [25] De Bastiani, M. A. et al. Cross-species evidence of differential expression of S100A6 and SLC11A1 in the hippocampus of Alzheimer’s disease patients and mouse models. Alzheimers Dement. 19, e060565 (2023). source
• ?Could not verify

  The Results section on mouse-brain DEGs reports differences between APOE2 and APOE4 genotypes, and the section on human AD brains examines preservation of gene modules. Neither passage reports that DEGs from an E4-to-E2 switch strongly overlap APOE- or AD-associated gene lists, particularly a merged LOAD list. Searches for “LOAD genes” and overlap with human transcriptomic gene lists did not find that analysis in our copy. (LLM, conf=0.74)

  cites [26] Zhao, N. et al. Alzheimer’s risk factors age, APOE genotype, and sex drive distinct molecular pathways. Neuron 106, 727–742 (2020). sourceExperimental — accuracy not yet measured
• Supported

  The paper identifies an AD-associated gene list: its Abstract (page unavailable) reports a 239-gene disease-associated astrocyte signature, including APOE. In this multi-citation sentence, Habib et al. can support the identification of an AD-associated list; the E4-to-E2 overlap is the citing authors’ own analysis, not a result attributed to Habib et al. (LLM, conf=0.84)

  cites [27] Habib, N. et al. Disease-associated astrocytes in Alzheimer's disease and aging. Nat. Neurosci. 23, 701–706 (2020). source
• Supported

  The Results (page not supplied) identify an AD-associated microglial gene-expression program in mice, including increased Apoe, Lpl, CD9, Cst7, and Trem2. This supports citing the paper as a source of an AD-associated gene list for the citing authors’ comparison; the E4-to-E2 overlap is the citing authors’ own analysis. (LLM, conf=0.84)

  cites [28] Keren-Shaul, H. et al. A unique microglia type associated with restricting development of Alzheimer’s disease. Cell 169, 1276–1290 (2017). source

In the paper

“In agreement with previous postmortem AD studies22,23, many of these lipids were glycerophospholipids, including many phosphatidylcholine (PC) and ceramide (CER) species.”

What the sources say

• Partly supported

  The Results section (page unavailable) reports differences in phospholipids, including PC, among APOE-genotype groups with AD. It does not report an APOE4s2G-versus-control comparison or identify many differing ceramide (CER) species. (LLM, conf=0.88)

  cites [22] Lefterov, I. et al. APOE2 orchestrated differences in transcriptomic and lipidomic profiles of postmortem AD brain. Alzheimers Res. Ther. 11, 113 (2019). sourceExperimental — accuracy not yet measured
• Partly supported

  The Results section (Fig. 1) reports APOE-dependent differences in phospholipids and includes phosphatidylcholine (PC) among the classes analyzed. It compares AD brains by APOE genotype and APOE3 versus APOE4 lipoproteins, not APOE4s2G with controls; the passages do not report differing ceramide (CER) species. Page numbers are unavailable in our copy. (LLM, conf=0.84)

  cites [23] Fitz, N. F. et al. Phospholipids of APOE lipoproteins activate microglia in an isoform-specific manner in preclinical models of Alzheimer’s disease. Nat. Commun. 12, 3416 (2021). sourceExperimental — accuracy not yet measured

In the paper

“Moving in vivo, other studies have explored vector-mediated delivery to supplement the E4 brain with neuroprotective E2 protein, showing that exogenous E2 markedly decreases amyloid burden in mice9–12.”

What the sources say

• Partly supported

  The Results report that lentiviral delivery of human apoE2 reduced hippocampal Aβ burden in PDAPP mice, including a 61.5% decrease versus controls after three months. The study does not show apoE2 supplementing an apoE4-expressing brain: the mice in the reported apoE2 experiment expressed endogenous mouse apoE. (LLM, conf=0.87)

  cites [9] Dodart, J.-C. et al. Gene delivery of human apolipoprotein E alters brain Aβ burden in a mouse model of Alzheimer’s disease. Proc. Natl Acad. Sci. USA 102, 1211–1216 (2005). sourceExperimental — accuracy not yet measured
• Partly supported

  The Results section reports that AAV4-delivered APOE2 reduced amyloid-plaque density in APP/PS1 mice, supporting the claim that exogenous E2 decreases amyloid burden. The Animals methods describe separate groups receiving APOE2 or APOE4 vectors; they do not establish that E2 was delivered to an E4-expressing brain, as the citing sentence suggests. No page numbers are available in our copy. (LLM, conf=0.86)

  cites [10] Hudry, E. et al. Gene transfer of human Apoe isoforms results in differential modulation of amyloid deposition and neurotoxicity in mouse brain. Sci. Transl. Med. 5, 212ra161 (2013). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [11] Zhao, L. et al. Intracerebral adeno-associated virus gene delivery of apolipoprotein E2 markedly reduces brain amyloid pathology in Alzheimer’s disease mouse models. Neurobiol. Aging 44, 159–172 (2016). source
• Supported

  In the Results section, AAV-mediated APOE2 delivery to APP/PS1/APOE4 mice produced APOE2 protein in the brain. High-dose animals had significantly less cortical amyloid plaque coverage than vehicle-treated animals (about 33% less), supporting the claim that exogenous E2 markedly decreases amyloid burden in mice. (LLM, conf=0.94)

  cites [12] Jackson, R. J. APOE2 gene therapy reduces amyloid deposition and improves markers of neuroinflammation and neurodegeneration in a mouse model of Alzheimer disease. Mol. Ther. 32, 1373–1386 (2024). source

In the paper

“Studies that have successfully targeted APOE using gene editing in induced pluripotent stem cells (iPSCs) provide strong proof of concept that in vitro editing of ε4 to ε3 or ε2 simultaneously ‘corrects’ several phenotypes, including glial transcriptomic profiles, lipid metabolism and other functional measures7,8.”

What the sources say

• Partly supported

  The Discussion and Results report editing APOE3 to APOE2 in hiPSC-derived cultures, with reductions in amyloid secretion and, in some cultures, phosphorylated tau. This paper does not report editing APOE4 to APOE3 or APOE2. Its Results use astrocyte RNA sequencing to identify cell populations, not to demonstrate correction of glial transcriptomic profiles or lipid metabolism (pages not specified in our copy). (LLM, conf=0.90)

  cites [7] Brookhouser, N., Raman, S., Frisch, C., Srinivasan, G. & Brafman, D. A. APOE2 mitigates disease-related phenotypes in an isogenic hiPSC-based model of Alzheimer’s disease. Mol. Psychiatry 26, 5715–5732 (2021). sourceExperimental — accuracy not yet measured
• Partly supported

  The Results section, “Converting APOE4 to APOE3,” reports that editing patient-derived iPSCs reduced astrocyte cholesterol accumulation and improved several neuronal and glial functional measures. It does not report an ε4-to-ε2 edit or show that the ε4-to-ε3 edit corrected glial transcriptomic profiles; the Discussion says APOE2’s effects warrant further study. Page numbers are unavailable in our copy. (LLM, conf=0.88)

  cites [8] Lin, Y. T. et al. APOE4 causes widespread molecular and cellular alterations associated with Alzheimer’s disease phenotypes in human iPSC-derived brain cell types. Neuron 98, 1141–1154 (2018). sourceExperimental — accuracy not yet measured

In the paper

“Because astrocytes synthesize most of CNS ApoE and were the cell type most affected by the global E4 to E2 transition, we generated APOE4s2loxP/loxP/Aldh1l1-CreERT2 APOE switch mice (APOE4s2A) that would express APOE4 in all CNS cell types except for astrocytes, which would selectively transition to APOE2 upon TAM injection29,30 (Fig. 4a).”

What the sources say

• ?Not checked — no full text of the sourcecites [29] Xu, Q. et al. Profile and regulation of apolipoprotein E (ApoE) expression in the CNS in mice with targeting of green fluorescent protein gene to the ApoE locus. J. Neurosci. 26, 4985–4994 (2006). source
• ?Could not verify

  The Results and Discussion describe an adult cortical astrocyte transcriptome, but do not state how much CNS ApoE astrocytes synthesize. Searches for ApoE and apolipoprotein E found no passage in our copy addressing that proportion. (LLM, conf=0.75)

  cites [30] Srinivasan, R. et al. New transgenic mouse lines for selectively targeting astrocytes and studying calcium signals in astrocyte processes in situ and in vivo. Neuron 92, 1181–1195 (2016). sourceExperimental — accuracy not yet measured

In the paper

“Because Sullivan et al.20 reported HLP-III-like plasma lipids in E2-TR mice”

What the sources say

• Supported

  The Results identify the APOE*2 homozygous (2/2) mice as having elevated plasma lipids. The Discussion states that these mice show virtually all the characteristics of human type III hyperlipoproteinemia, including elevated cholesterol and triglycerides and characteristic lipoprotein patterns. Page numbers are not available in the supplied passages. (LLM, conf=0.94)

  cites Sullivan et al.20 Sullivan, P., Mezdour, H., Quarfordt, S. & Maeda, N. Type III hyperlipoproteinemia and spontaneous atherosclerosis in mice resulting from gene replacement of mouse Apoe with human Apoe*2. J. Clin. Invest. 102, 130–135 (1998). source

In the paper

“several pathways altered by a short-term E4 to E2 transition were cellular pathways that are also perturbed across 17 large-scale human AD snRNA-seq studies24.”

What the sources say

• Partly supported

  The Introduction reports that several human AD snRNA-seq studies find altered cellular pathways, and describes shared disturbances in lipid handling, immune response, and metabolism. It does not establish that these pathways overlap with those altered by a short-term E4-to-E2 transition, or that the finding spans 17 large-scale studies. (LLM, conf=0.84)

  cites [24] Murdock, M. H. & Tsai, L.-H. Insights into Alzheimer’s disease from single-cell genomic approaches. Nat. Neurosci. 26, 181–195 (2023). sourceExperimental — accuracy not yet measured

In the paper

“These findings may reflect human AD studies in which both E4 and E2 carriage were associated with higher CAA compared to E3/E3 individuals47,48”

What the sources say

• ?Could not verify

  The Burden of CAA section reports an association between CAA and AD pathology, but does not compare CAA burden by APOE genotype. Searches for APOE, apolipoprotein E, and the E2/E4 alleles found no passage addressing whether either allele is associated with higher CAA than E3/E3. (LLM, conf=0.76)

  cites [47] Boyle, P. A. et al. Cerebral amyloid angiopathy and cognitive outcomes in community-based older persons. Neurology 85, 1930–1936 (2015). sourceExperimental — accuracy not yet measured
• Supported

  The Results report higher CAA scores for both APOE-ε3/4 and APOE-ε2/3 brains than for APOE-ε3/3 brains. The Patients section describes a human autopsy cohort assembled for studies of normal aging and AD; the claim does not require that every individual had AD. (LLM, conf=0.91)

  cites [48] Nelson, P. T. et al. APOE-ε2 and APOE-ε4 correlate with increased amyloid accumulation in cerebral vasculature. J. Neuropathol. Exp. Neurol. 72, 708–715 (2013). source

In the paper

“Across multiple studies, glial cells show APOE4-associated transcriptomic changes in both human E4+ brains and E4-TR mice5.”

What the sources say

• Partly supported

  In “ApoE and intracellular trafficking dysregulation” (page unavailable), the review reports transcriptomic differences between apoE4-TR and apoE3-TR mouse brains. Its References also list a study of APOE4-associated transcriptomic changes in primary mouse microglia. Our copy does not establish the corresponding claim about glial transcriptomic changes in human E4+ brains. (LLM, conf=0.78)

  cites [5] Martens, Y. A. et al. ApoE cascade hypothesis in the pathogenesis of Alzheimer’s disease and related dementias. Neuron 110, 1304–1317 (2022). sourceExperimental — accuracy not yet measured

In the paper

“Second, the 5xFAD model used in this study provided a model with well-characterized APOE-dependent changes in amyloid pathology55,63,64.”

What the sources say

• Supported

  The Methods section describes EFAD mice as a cross between 5xFAD mice and apoE-targeted replacement mice. The paper reports APOE-dependent differences in amyloid-related measures in those 5xFAD-derived mice. The source therefore supports the model characterization, with the qualification that its APOE comparisons use EFAD mice rather than unmodified 5xFAD mice. (LLM, conf=0.85)

  cites [55] Tai, L. M. et al. Levels of soluble apolipoprotein E/amyloid-β (Aβ) complex are reduced and oligomeric Aβ increased with APOE4 and Alzheimer disease in a transgenic mouse model and human samples. J. Biol. Chem. 288, 5914–5926 (2013). source
• Partly supported

  The 'Development of the EFAD mouse model' section says 5xFAD mice were bred with human APOE targeted-replacement mice to create EFAD lines. The 'APOE modulated AD symptoms exhibited in EFAD mice' section documents APOE-dependent amyloid changes in those EFAD lines, but distinguishes them from ordinary 5xFAD mice, which express mouse apoE. Thus the source supports the changes in a 5xFAD-derived model, not in unmodified 5xFAD mice. (LLM, conf=0.87)

  cites [63] Tai, L. M. et al. EFAD transgenic mice as a human APOE relevant preclinical model of Alzheimer’s disease. J. Lipid Res. 58, 1733–1755 (2017). sourceExperimental — accuracy not yet measured
• Supported

  The EFAD mice section identifies EFAD as a 5xFAD-based model designed to study APOE-dependent AD pathology. The Aged male and female EFAD mice section reports that cortical amyloid-β deposition varied by APOE genotype, sex, and age. The evidence specifically concerns 5xFAD mice carrying human APOE variants. (LLM, conf=0.87)

  cites [64] Balu, D. et al. The role of APOE in transgenic mouse models of AD. Neurosci. Lett. 707, 134285 (2019). source

In the paper

“Aldh1l1 is also expressed in the liver65, as evidenced by the plasma lipid profile of APOE4s2A mice.”

What the sources say

• ?Could not verify

  The Description reports Aldh1l1 promoter activity in the salivary gland, lymph nodes, pancreas, and spleen, but does not address the liver. Searches for liver or hepatic expression and for the APOE4s2A plasma lipid profile found no supporting passage in our copy. The citation is attached specifically to the liver-expression claim. (LLM, conf=0.76)

  cites [65] Nemeth, D., Luqman, N., Chen, L. & Quan, N. Aldh1l1-Cre/ER T2 is expressed in unintended cell types of the salivary gland, pancreas, and spleen. MicroPubl. Biol. https://doi.org/10.17912/micropub.biology.000832 (2023). sourceExperimental — accuracy not yet measured

In the paper

“First, the degree of risk and protection afforded by E4 and E2 respectively vary according to ancestry1,59–62.”

What the sources say

• Supported

  The Results (Race and Ethnicity Analyses; page not provided) report different Alzheimer disease risk estimates for APOE*4 and different protective associations for APOE*2 across groups. The Results (Global Population Ancestry Analyses; page not provided) also report an ancestry-related pattern for APOE*4, although ancestry did not explain every difference between groups. (LLM, conf=0.90)

  cites [1] Belloy, M. E. et al. APOE genotype and Alzheimer disease risk across age, sex, and population ancestry. JAMA Neurol. 80, 1284–1294 (2023). source
• Partly supported

  The Introduction (page unavailable) states that Alzheimer’s disease risk associated with APOE ε4 varies by ancestral background, including a comparison of risk across three populations. It does not address whether the protection afforded by ε2 varies by ancestry; a search for ε2 found no relevant passage. (LLM, conf=0.88)

  cites [59] Griswold, A. J. et al. Increased APOE ε4 expression is associated with the difference in Alzheimer’s disease risk from diverse ancestral backgrounds. Alzheimers Dement. 17, 1179–1188 (2021). sourceExperimental — accuracy not yet measured
• Partly supported

  The Discussion (page unavailable) reports that the association between APOE ε4 and dementia risk varies across Hispanic groups and discusses genetic ancestry as a possible explanation. The Results (page unavailable) say the analysis focused on ε4 carriers; although ε2 genotypes are listed, the paper does not establish that ε2’s protective effect varies by ancestry. (LLM, conf=0.90)

  cites [60] Huggins, L. K. L. et al. Meta-analysis of variations in association between APOE ɛ4 and Alzheimer’s disease and related dementias across Hispanic regions of origin. J. Alzheimers Dis. 93, 1095–1109 (2023). sourceExperimental — accuracy not yet measured
• Partly supported

  Results §3.1 reports that the Alzheimer’s disease risk associated with ε4 differs across ethnic groups. But the Introduction explicitly says the protective effect of ε2 does not vary by ethnicity, contrary to that part of the claim. Page numbers are unavailable in our copy. (LLM, conf=0.90)

  cites [61] & Choi, K. Y. APOE promoter polymorphism-219T/G is an effect modifier of the influence of APOE ε4 on Alzheimer's disease risk in a multiracial sample. J. Clin. Med. 8, 1236 (2019). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [62] Eisenberg, D. T., Kuzawa, C. W. & Hayes, M. G. Worldwide allele frequencies of the human apolipoprotein E gene: climate, local adaptations, and evolutionary history. Am. J. Phys. Anthropol. 143, 100–111 (2010). source

In the paper

“There was also substantial overlap (39–60% depending on the cell type) between the specific DEGs associated with a global versus astrocyte-specific E4 to E2 switch (Fig. 4g).”

In the paper

“A whole-body allelic switch results in a metabolic profile resembling E2/E2 humans and drives AD-relevant alterations in the lipidome and single-cell transcriptome, particularly in astrocytes.”

In the paper

“Interestingly, there were nuanced changes within these lipid classes; in both PC and CER classes, some lipid species increased in abundance while others decreased.”

In the paper

“Across all cell types, pathway analyses of astrocyte switch DEGs revealed similar terms to those seen in whole-body APOE4s2G mice, particularly in pathways related to neurotransmission, redox status and metabolite transport (Fig. 4h–k).”

In the paper

“A whole-body allelic switch results in a metabolic profile resembling E2/E2 humans and drives AD-relevant alterations in the lipidome and single-cell transcriptome, particularly in astrocytes.”

• Also stated in: § Main · plain

  “The metabolic profile of post-switch APOE4s2 mice resembled that of humanized APOE2 ‘targeted replacement’ (TR) mice and E2/E2 humans, with elevated ApoE concentrations and increased plasma lipids.”

In the paper

“Analysis of DEGs showed that the astrocyte-specific APOE4 to APOE2 transition primarily affected similar cell types as observed in the global model (Fig. 4e and Extended Data Fig. 5).”

In the paper

“While the Aldh1l1-CreERT2 showed high specificity for astrocytes in the brain; plasma lipid profiling and peripheral ApoE measures indicated that there is also notable E2 expression in the periphery (Extended Data Fig. 5d,e).”

In the paper

“While the Morris water maze did not show striking differences in spatial learning or memory, 4s2A/FAD mice showed improvements in associative learning and more robust contextual and cued memory, an effect that was strongest in females (Fig. 5b–d and Extended Data Fig. 6a–d).”

In the paper

“When compared to ‘baseline’ amyloid measures at 6 months of age, the reduced burden in 4s2A/FAD mice was due to slowed or delayed amyloid accumulation (Fig. 5f and Extended Data Fig. 7).”

In the paper

“Finally, when crossed to the 5xFAD background, astrocyte-specific E4 to E2 switching improves cognition, decreases amyloid pathology, lowers gliosis and reduces plaque-associated apolipoprotein E.”

• Also stated in: § Astrocyte-only E4 to E2 switch decreases amyloid plaque load · plain

  “4s2A/FAD mice showed improvements in associative learning and more robust contextual and cued memory, an effect that was strongest in females (Fig. 5b–d and Extended Data Fig. 6a–d).”

In the paper

“While the Morris water maze did not show striking differences in spatial learning or memory, 4s2A/FAD mice showed improvements in associative learning and more robust contextual and cued memory, an effect that was strongest in females (Fig. 5b–d and Extended Data Fig. 6a–d).”

In the paper

“Before TAM, total plasma triglyceride (TG) levels in APOE4s2 and APOE4s2G mice were indistinguishable from the E4-TR controls (Fig. 2a).”

In the paper

“Finally, when crossed to the 5xFAD background, astrocyte-specific E4 to E2 switching improves cognition, decreases amyloid pathology, lowers gliosis and reduces plaque-associated apolipoprotein E.”

In the paper

“Additionally, as seen in the whole-body model, the DEGs associated with an astrocyte-specific E4 to E2 switch also strongly mirrored the LOAD gene lists (Fig. 4f).”

In the paper

“Finally, when crossed to the 5xFAD background, astrocyte-specific E4 to E2 switching improves cognition, decreases amyloid pathology, lowers gliosis and reduces plaque-associated apolipoprotein E.”

• Also stated in: § Astrocyte-only E4 to E2 switch decreases amyloid plaque load · boosted

  “Strikingly, after a 2-month astrocyte-specific allelic switch, 4s2A/FAD animals showed significant reductions in total amyloid levels (Fig. 5e,f and Extended Data Fig. 6e–h).”

In the paper

“To generate a preclinical model in which we could investigate the feasibility and therapeutic potential of a full APOE4 to APOE2 transition in vivo, we developed a knock-in model coined the APOE ‘switch’ mouse (APOE4s2).”

In the paper

“Brain ApoE levels were also elevated in APOE4s2G mice 1 month after switching (Fig. 2f).”

In the paper

“A comparison of APOE4s2G mice versus Cre− APOE4s2 controls identified 14 lipid species that were significantly different in abundance between the two groups (Fig. 2i,j).”

In the paper

“Finally, when crossed to the 5xFAD background, astrocyte-specific E4 to E2 switching improves cognition, decreases amyloid pathology, lowers gliosis and reduces plaque-associated apolipoprotein E.”

In the paper

“Analysis of differentially expressed genes (DEGs) revealed astrocytes, oligodendrocytes, microglia and endothelial cells as the cell types most affected by a 1-month-long APOE4 to APOE2 switch (Fig. 3b, Extended Data Fig. 4 and Supplementary Table 1).”

In the paper

“Strikingly, after a 2-month astrocyte-specific allelic switch, 4s2A/FAD animals showed significant reductions in total amyloid levels (Fig. 5e,f and Extended Data Fig. 6e–h).”

In the paper

“Anatomical analyses revealed decreases in many regions, with significant reductions in the hippocampus, olfactory area and thalamus primarily driving the decrease in plaque load (Fig. 5g,h).”

In the paper

“Across these cell types, there was notable overlap of DEGs from APOE4s2G mice versus APOE4s2 controls with DEGs from E2-TR versus E4-TR mice (Fig. 3c), suggesting that many genes that distinguish ‘lifetime’ expression of E4 are acutely malleable.”

In the paper

“APOE4s2G mice fed a normal chow diet also showed elevations in TGs, cholesterol and phospholipids relative to the APOE4s2 controls, although the increases were more modest (Extended Data Fig. 2e–j).”

In the paper

“Interestingly, several cell types that continued expressing E4 in APOE4s2A mice (that is, microglia, oligodendrocytes) still showed a high number of DEGs, suggesting non-cell-autonomous effects of astrocyte-derived E2.”

In the paper

“For reference, a comparison of E2-TR and E4-TR control mice identified 57 lipids of differing abundance, again most of which were glycerophospholipids (Extended Data Fig. 2o,p).”

In the paper

“Gene Ontology (GO) analysis of switch-related DEGs highlighted a number of pathways related to metabolism, including substrate transport, redox management and cellular respiration (Fig. 3d–g and Supplementary Table 2).”

In the paper

“A whole-body allelic switch results in a metabolic profile resembling E2/E2 humans and drives AD-relevant alterations in the lipidome and single-cell transcriptome, particularly in astrocytes.”

In the paper

“Together, these data demonstrate that even a short-term transition from E4 to E2 in the adult mouse is sufficient to drive alterations in ApoE concentrations and lipid metabolism, most notably increases in multiple PC species within the brain.”

In the paper

“Enzyme-linked immunosorbent assay (ELISA) quantification of Aβ42 and Aβ40 in whole-brain soluble and insoluble fractions revealed reductions in both soluble and insoluble Aβ42 and Aβ40 observed in 4s2A/FAD brains (Fig. 5i–l and Extended Data Fig. 7).”

In the paper

“we describe a new APOE ‘switch’ model (APOE4s2) that allows for inducible, cell-specific, in vivo replacement of the high-risk APOE4 allele with the protective APOE2 variant.”

In the paper

“ELISA quantification of ApoE supported these findings, with significant reductions of ApoE within the insoluble (plaque-associated) brain fractions from 4s2A/FAD mice, but no differences in soluble ApoE (Fig. 7i,j and Extended Data Fig. 9n,o).”

In the paper

“Strikingly, we show that a 2-month-long astrocyte-specific E4 to E2 switch after pathology onset is sufficient to decrease plaque load, reduce markers of glial reactivity and improve associative, but not spatial, memory in the 5xFAD model.”

In the paper

“While higher amyloid plaque loads were observed in female compared to male 4s2/FAD Cre− controls, we did not detect any other amyloid-dependent sex differences, nor was this difference reflected in the soluble and insoluble Aβ42 and Aβ40 measures (Extended Data Fig. 7e–h).”

In the paper

“However, these intense bursts of plaque-associated ApoE signal were largely absent in 4s2A/FAD mice”

In the paper

“In this study, we observed that expression of astrocytic E2 slowed amyloid deposition during the 2-month period after the allelic switch in 4s2A/FAD mice.”

In the paper

“4s2A/FAD mice showed decreased colocalization of amyloid with GFAP+ and IBA1+ puncta (Fig. 6f–i and Extended Data Fig. 8d–g)”

In the paper

“Although there was no change in homeostatic gene expression, decreased expression of several disease-associated microglia (DAM) genes, including Trem2, Clec7a and APOE, was also noted after the astrocyte-specific transition to E2 (Fig. 7e,f and Extended Data Fig. 9g,h).”

In the paper

“Reductions in total GFAP and IBA1 levels were especially pronounced in close proximity to amyloid plaques.”

In the paper

“we also observed significantly lower levels of GFAP in 4s2A/FAD mice compared to controls (Fig. 6a,b).”

In the paper

“Finally, we measured the expression of the tight junction protein ZO1 and found no change after the switch to astrocyte-derived E2 (Extended Data Fig. 7n–r).”

In the paper

“we noted a dramatic reduction in microglial IBA1 positivity (Fig. 6c)”

In the paper

“While there was no difference in total ApoE protein levels between the 4s2A/FAD and 4s2/FAD mice, we observed a striking difference in plaque-associated ApoE.”

In the paper

“In this study, we show that short-term expression of astrocyte-derived E2 reduces proximity and colocalization of reactive microglia to plaques.”

In the paper

“These findings were mirrored by histopathological reductions in microglial reactivity in 4s2A/FAD mice”

In the paper

“4s2A/FAD mice showed a decrease in total MHC-II+ area and a decrease in colocalization between MHC-II + IBA1+ cells and amyloid plaques (Fig. 7a–d and Extended Data Fig. 9a–f)”

In the paper

“We further show that an astrocyte-selective replacement of E4 with E2 significantly alters the transcriptomic profiles of multiple CNS cell types, reduces amyloid plaque load, dampens gliosis and improves cognitive outcomes in an amyloidosis model of AD.”

In the paper

“We further show that an astrocyte-selective replacement of E4 with E2 significantly alters the transcriptomic profiles of multiple CNS cell types, reduces amyloid plaque load, dampens gliosis and improves cognitive outcomes in an amyloidosis model of AD.”

In the paper

“Control mice expressing E4 in all cell types displayed many bright halos of ApoE staining surrounding the cores of plaques (Fig. 7g,h and Extended Data Fig. 8i–m).”

In the paper

“Despite reductions in parenchymal plaque load, we observed similar levels of CAA in the 4s2A/FAD and 4s2/FAD mice.”

In the paper

“Further analyses of these DEGs revealed that the pathways most affected by the E4 to E2 switch—both whole-body and astrocyte-specific—were pathways centered on cerebral metabolism, inflammation and cytoskeleton/vascular integrity”

In the paper

“sex-based analysis showed significantly more cortical plaques with MHC-II+ microglia in female mice than males (Extended Data Fig. 9c).”

In the paper

“Direct comparison of the DEGs distinguishing E2-TR from E4-TR mice to the DEGs of APOE4s2G versus APOE4s2 mice showed some commonality (~20%) across multiple cell types”

In the paper

“the most significantly upregulated lipid in our dataset is a CER (Cer(d40:2)) involved in glucosylceramide synthesis”

In the paper

“Interestingly, we observed no differences in CAA between 4s2A/FAD and 4s2/FAD controls at 8 months of age (Fig. 5m,n).”

In the paper

“Although there was no change in homeostatic gene expression, decreased expression of several disease-associated microglia (DAM) genes, including Trem2, Clec7a and APOE, was also noted after the astrocyte-specific transition to E2 (Fig. 7e,f and Extended Data Fig. 9g,h).”

In the paper

“While there was no difference in total ApoE protein levels between the 4s2A/FAD and 4s2/FAD mice, we observed a striking difference in plaque-associated ApoE.”

In the paper

“We further show that an astrocyte-selective replacement of E4 with E2 significantly alters the transcriptomic profiles of multiple CNS cell types, reduces amyloid plaque load, dampens gliosis and improves cognitive outcomes in an amyloidosis model of AD.”

In the paper

“peripheral phenotyping of APOE4s2G mice showed that the in vivo E4 to E2 switch shifted animals to an HLP-III-like plasma lipid profile.”

In the paper

“We further show that an astrocyte-selective replacement of E4 with E2 significantly alters the transcriptomic profiles of multiple CNS cell types, reduces amyloid plaque load, dampens gliosis and improves cognitive outcomes in an amyloidosis model of AD.”

In the paper

“untargeted lipidomic profiling of the brain revealed that the allelic switch altered multiple PC, CER and lyso-PC (LPC) species”

In the paper

“ELISA quantification of ApoE supported these findings, with significant reductions of ApoE within the insoluble (plaque-associated) brain fractions from 4s2A/FAD mice, but no differences in soluble ApoE (Fig. 7i,j and Extended Data Fig. 9n,o).”

In the paper

“Importantly, this overlap with AD scRNA-seq datasets occurred in both the global and astrocyte-specific switch models that lack overt AD pathology.”

In the paper

“Strikingly, we show that a 2-month-long astrocyte-specific E4 to E2 switch after pathology onset is sufficient to decrease plaque load, reduce markers of glial reactivity and improve associative, but not spatial, memory in the 5xFAD model.”

In the paper

“GFAP and IBA1 levels were most substantially decreased in the hippocampus, thalamus and cortical areas (Fig. 6d,e and Extended Data Fig. 8a–c).”

In the paper

“4s2A/FAD mice showed a decrease in total MHC-II+ area and a decrease in colocalization between MHC-II + IBA1+ cells and amyloid plaques (Fig. 7a–d and Extended Data Fig. 9a–f)”

In the paper

“Lastly, we show that a late disease stage ‘switch’ to expression of astrocytic E2 reduces plaque-associated ApoE.”

In the paper

“Overall, there were very few sex differences in AD-related pathology.”

In the paper

“Together, these data show that a short-term transition from APOE4 to APOE2 can broadly affect the cerebral transcriptome and lipidome, and that astrocyte-specific APOE replacement may be a viable strategy for future gene editing approaches to simultaneously reduce multiple AD-associated pathologies.”

In the paper

“Collectively, these results demonstrate that, even in the absence of AD pathology, a postdevelopmental transition from expression of E4 to E2 is sufficient to drive transcriptomic changes in pathways previously implicated in AD.”

In the paper

“Together, these data suggest that astrocyte-exclusive expression of E2 is sufficient to drive AD-relevant alterations in the glial transcriptome, even when all other cell types continue to express E4 and even in a model that lacks overt AD pathology.”

In the paper

“Together, these data show that a short-term transition from APOE4 to APOE2 can broadly affect the cerebral transcriptome and lipidome, and that astrocyte-specific APOE replacement may be a viable strategy for future gene editing approaches to simultaneously reduce multiple AD-associated pathologies.”

In the paper

“Cell-type specificity was confirmed via colocalization of GFAP with tdTomato expression in APOE4s2A mice crossed to an Ai9 Cre reporter strain (Fig. 4b and Extended Data Fig. 5a).”

In the paper

“Together, these studies suggest that an approach where E4 is eliminated and replaced with E2 could be a highly effective therapeutic strategy.”

In the paper

“Excitingly, this may suggest that the overarching cellular pathways that define AD in the human brain could be altered by transitioning from E4 to E2.”

In the paper

“highlighting potential differential effects of the E2 versus E4 isoforms on plaque expansion or compaction.”

In the paper

“Our results showing changes in microglia, oligodendrocyte and endothelial cell transcriptomes after the astrocyte-selective switch also suggest strong non-cell-autonomous effects of astrocyte-derived E2.”

In the paper

“again suggestive of non-cell-autonomous effects of ApoE2.”

In the paper

“suggest an alternative scenario where astrocyte-derived E2 could be having non-cell-autonomous effects on microglial activation and response to plaque”

In the paper

“Rather, many of these DEGs are acutely malleable, at least within the specific parameters tested in this study.”

In the paper

“Interestingly, these are the same primary cell types affected by a short-term E4 to E2 transition.”

In the paper

“Together, these findings highlight a strong decrease in plaque-associated astro-gliosis and micro-gliosis after an astrocytic E4 to E2 switch.”

In the paper

“and that these various measures of gliosis differentially correlate with memory.”

In the paper

“the increases in plasma TGs and ApoE observed in APOE4s2G mice ‘after the switch’ were exciting confirmatory results regarding the effectiveness of our model design.”

In the paper

“indicating a reduction in ARMs after the 2-month astrocyte-specific switch to E2.”

In the paper

“suggesting that E4’s transcriptional signature is not permanently established during development or early life.”

In the paper

“Our findings, taken together with the literature, suggest that astrocyte-derived E4’s ability to bind Aβ increases Aβ accumulation and ApoE protein aggregation within or surrounding the plaque.”

In the paper

“Our study suggests that astrocyte-exclusive ‘switching’ from E4 to E2 in the CNS can mitigate AD pathologies”