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Cited by 72Alzheimer's disease research and treatmentsDementia and Cognitive Impairment ResearchNeuroinflammation and Neurodegeneration Mechanisms

Amyloid precursor protein-induced axonopathies are independent of amyloid-β peptides

Open access
Stokin, Gorazd B., Almenar-Queralt, Angels, Gunawardena, Shermali, Rodrigues, Elizabeth M., Falzone, Tomás, Kim, Jungsu, Lillo, Concepción, Mount, Stephanie L. +4 more·2008·Human Molecular Genetics
DOI 10.1093/hmg/ddn240PMC PMC2722897
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Abstract

Overexpression of amyloid precursor protein (APP), as well as mutations in the APP and presenilin genes, causes rare forms of Alzheimer's disease (AD). These genetic changes have been proposed to cause AD by elevating levels of amyloid-beta peptides (Abeta), which are thought to be neurotoxic. Since overexpression of APP also causes defects in axonal transport, we tested whether defects in axonal transport were the result of Abeta poisoning of the axonal transport machinery. Because directly varying APP levels also alters APP domains in addition to Abeta, we perturbed Abeta generation selectively by combining APP transgenes in Drosophila and mice with presenilin-1 (PS1) transgenes harboring mutations that cause familial AD (FAD). We found that combining FAD mutant PS1 with FAD mutant APP increased Abeta42/Abeta40 ratios and enhanced amyloid deposition as previously reported. Surprisingly, however, this combination suppressed rather than increased APP-induced axonal transport defects in both Drosophila and mice. In addition, neuronal apoptosis induced by expression of FAD mutant human APP in Drosophila was suppressed by co-expressing FAD mutant PS1. We also observed that directly elevating Abeta with fusions to the Familial British and Danish Dementia-related BRI protein did not enhance axonal transport phenotypes in APP transgenic mice. Finally, we observed that perturbing Abeta ratios in the mouse by combining FAD mutant PS1 with FAD mutant APP did not enhance APP-induced behavioral defects. A potential mechanism to explain these findings was suggested by direct analysis of axonal transport in the mouse, which revealed that axonal transport or entry of APP into axons is reduced by FAD mutant PS1. Thus, we suggest that APP-induced axonal defects are not caused by Abeta.

AI snapshot

Written from the paper’s full text.

TL;DR

Combining FAD mutant presenilin-1 with FAD mutant APP increased Aβ42/Aβ40 ratios and amyloid deposition but suppressed, rather than enhanced, APP-induced axonal transport defects in Drosophila and mice. The authors conclude that APP-induced axonopathies are not caused by Aβ peptides.

Key findings

  • In 4-month-old mice, single transgenic Tg-swAPP PrP had significantly higher percentages of ChAT-IR fibers with large varicosities in the basal nucleus (2.7–3.6, 3.6–4.5, and >4.5 µm) and sensory cortex (1.4–2.0, 2.0–2.6, and >2.6 µm) than WT, whereas double transgenic Tg-swAPP PrP;Tg-A246EPS1 PrP showed no differences from WT in either genetic background.
  • BRI-Aβ40 or BRI-Aβ42 fusions dramatically altered Aβ levels—e.g., 10–11-month-old Tg-swAPP PrP;Tg-BRI-Aβ42 PrP had 24,499.67 ± 4,841.7 fmol/mg Aβ40 and 9,394.67 ± 2,554.19 fmol/mg Aβ42 versus 2,935.4 ± 575.35 and 1,561.2 ± 166.76 fmol/mg in Tg-swAPP PrP—but did not change the frequency of axonal pathology.
  • In Drosophila, co-expression of FAD mutant presenilin PsnE280A with FAD mutant APP suppressed APP-induced axonal blockages and TUNEL-positive apoptotic neurons.
  • FAD mutant PS1 did not enhance APP-induced behavioral deficits; it partially suppressed rotarod deficits, and Tg-swAPP PrP but not Tg-swAPP PrP;Tg-A246EPS1 PrP mice showed cued conditioning deficits versus WT. Sciatic nerve ligation suggested FAD mutant PS1 reduced anterograde axonal transport of APP.

Methods

  • Transgenic mouse crosses: Tg-swAPP PrP × Tg-A246EPS1 PrP in C57BL/6J/C3H/HeJ and C57BL/6J backgrounds, examined at 4 months unless otherwise stated; Tg-swAPP PrP × BRI-Aβ40 or BRI-Aβ42 mice examined at 10–11 months. Drosophila used APPL-GAL4 with UAS-SWE and/or UAS-PsnE280A.
  • Outcomes included blinded ChAT immunohistochemistry and immuno-electron microscopy of basal nucleus and sensory cortex, Drosophila CSP immunofluorescence and TUNEL, behavioral battery (open field, rotarod, fear conditioning), sciatic nerve ligation with western blotting, and Aβ ELISAs.
  • Statistics used Kruskal–Wallis non-parametric ANOVA and Mann–Whitney U-test, or ANOVA with Scheffe’s post hoc test, at P < 0.05.

Limitations

  • Stated in the paper: WT samples could not be analyzed in the BRI mouse histology owing to poor staining quality; the authors state that further work is necessary to discriminate between possible mechanisms.
  • Evident from the text: conclusions rely on transgenic Drosophila and mouse models rather than human AD tissue, and the mechanism by which FAD mutant PS1 suppresses APP-induced phenotypes is not established.
  • Evident from the text: some histology groups were small (e.g., n = 3 per genotype in Fig. 1D; n = 5 per Drosophila group), and several behavioral effects were partial or mild rather than absent.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1093/hmg/ddn240

Cites

89 of 89 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

3 of 37 cited sources checked · 2 supported · 1 flagged · accuracy not yet measured

  • Premisecitation

    Increasing Aβ by expressing FAD mutant PS1 together with FAD mutant APP failed to produce substantial enhancements of the behavioral deficits observed in mice overexpressing FAD mutant APP alone.

    “Our findings are also consistent with research showing that increasing Ab by expressing FAD mutant PS1 together with FAD mutant APP failed to produce substantial enhancements of the behavioral deficits observed in mice overexpressing FAD mutant APP alone (56)(57)(58).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [56] Dineley, 2002, Accelerated plaque accumulation, associative learning deficits, and up-regulation of alpha 7 nicotinic receptor protein in transgenic mice co-expressing mutant human presenilin 1 and amyloid precursor proteins, J. Biol. Chem. source

      The Discussion (page not provided) says the contextual fear-learning deficit was more pronounced in PS-1/APP mice, contrary to the claim that adding mutant PS-1 failed to substantially enhance the behavioral deficit. The reported comparison at five months also found that APP-only mice performed significantly better than PS-1/APP mice after more intensive training. (LLM, conf=0.88)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • cites [57] Holcomb, 1998, Accelerated Alzheimer-type phenotype in transgenic mice carrying both mutant amyloid precursor protein and presenilin 1 transgenes, Nat. Med. source
    • cites [58] Holcomb, 1999, Behavioral changes in transgenic mice expressing both amyloid precursor protein and presenilin-1 mutations: lack of association with amyloid deposits, Behav. Genet. source
  • Findingown data

    In 4-month-old Tg-swAPP Prp mice, the increase in APP accumulation at the proximal ligature site was less than in WT.

    “In 4-month-old Tg-swAPP Prp mice, although we observed an increase in APP accumulation at the proximal ligature site, the extent was less than in WT, suggesting a reduction in the anterograde axonal transport of APP upon its overexpression.”
    Quote in the paperSubstantial claim
  • Findingown data

    Expression of PsnE280A alone had no obvious effect on axonal phenotypes.

    “Note that the expression of PsnE280A alone had no obvious effect on axonal phenotypes.”
    Quote in the paperSubstantial claim
  • Findingown data

    Expression of the Swedish mutant of APP in combination with PsnE280A failed to induce axonal blockages in Drosophila larval segmental nerves.

    “Strikingly, expression of the Swedish mutant of APP in combination with PsnE280A (Fig. 2A and B) failed to induce axonal blockages.”
    Quote in the paperSubstantial claim
  • Findingown data

    Combining FAD mutant PS1 with FAD mutant APP suppressed rather than increased APP-induced axonal transport defects in both Drosophila and mice.

    “Surprisingly, however, this combination suppressed rather than increased APP-induced axonal transport defects in both Drosophila and mice.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 22
  • May combine two claims. 34
  • The quote only partly states this claim. 2

  • Classified as probably not a substantial claim.

    Premisecitation

    Overexpression of WT and FAD mutant human APP and Drosophila APPL in the Drosophila larval nervous system causes axonal blockages reminiscent of those found in mutants for molecular motors.

    “Previous work showed that overexpression of WT and FAD mutant human APP and Drosophila APPL in the Drosophila larval nervous system causes axonal blockages reminiscent of those found in mutants for molecular motors (29,30,50).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [29] Gunawardena, 2001, Disruption of axonal transport and neuronal viability by amyloid precursor protein mutations in Drosophila, Neuron source
    • cites [30] Torroja, 1999, Neuronal overexpression of APPL, the Drosophila homologue of the amyloid precursor protein (APP), disrupts axonal transport, Curr. Biol. source
    • cites [50] Hurd, 1996, Kinesin mutations cause motor neuron disease phenotypes by disrupting fast axonal transport in Drosophila, Genetics source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The density of cortical cholinergic synapses has been shown to increase in mice overexpressing FAD mutant APP and decreased in mice expressing FAD mutant APP combined with FAD mutant PS1.

    “Similarly, the density of cortical cholinergic synapses has been shown to increase in mice overexpressing FAD mutant APP and decreased in mice expressing FAD mutant APP combined with FAD mutant PS1 (52).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [52] Wong, 1999, Reorganization of cholinergic terminals in the cerebral cortex and hippocampus in transgenic mice carrying mutated presenilin-1 and amyloid precursor protein transgenes, J. Neurosci. source

  • May combine two claims.

    Findingown data

    Data collected by either observer revealed comparable percentages of fibers with varicosities in all diameter intervals examined among Tg-swAPP Prp, Tg-BRI-Aβ40 Prp and Tg-BRI-Aβ42 Prp and no differences among Tg-swAPP Prp, Tg-swAPP Prp; Tg-BRI-Aβ40 Prp and Tg-swAPP Prp; Tg-BRI-Aβ42 Prp littermates despite dramatic changes in Aβ levels and amyloid deposition.

    “Data collected by either of the observers revealed comparable percentages of fibers with varicosities in all of the diameter intervals examined among Tg-swAPP Prp , Tg-BRI-Ab40 Prp and Tg-BRI-Ab42 Prp and no differences in the percentage of fibers with varicosities in any of the diameter intervals among Tg-swAPP Prp , Tg-swAPP Prp ; Tg-BRI-Ab40 Prp and Tg-swAPP Prp ; Tg-BRI-Ab42 Prp littermates”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    TUNEL-positive neurons were observed in animals expressing FAD mutant APP alone, but not in combination with FAD mutant presenilin.

    “We observed TUNEL-positive neurons in animals expressing FAD mutant APP alone, but not in combination with FAD mutant presenilin (Fig. 2C and D).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The length of cholinergic fibers per field at their termini was significantly increased in Tg-swAPP Prp and significantly decreased in double transgenic Tg-swAPP Prp; Tg-A246EPS1 Prp compared with WT and Tg-A246EPS1 Prp littermates.

    “Surprisingly, in contrast to fibers in the BN, we found that the length of cholinergic fibers per field at their termini was significantly increased in Tg-swAPP Prp and significantly decreased in Tg-swAPP Prp ; Tg-A246EPS1 Prp compared with WT and Tg-A246EPS1 Prp littermates”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    All of these transgenic mice except for Tg-BRI-Aβ40 Prp exhibited amyloid deposition, with Tg-swAPP Prp; Tg-BRI-Aβ42 Prp demonstrating the most extensive amyloid deposition.

    “All of these transgenic mice except for Tg-BRI-Ab40 Prp exhibited amyloid deposition with Tg-swAPP Prp ; Tg-BRI-Ab42 Prp demonstrating the most extensive amyloid deposition.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Although expressing FAD mutant PS1 with overexpression of FAD mutant APP enhances Aβ42 production and amyloid deposition, it suppresses axonal defects and gives mild suppression, as opposed to enhancement, of other defects such as behavior.

    “In conclusion, it is surprising that although expressing FAD mutant PS1 with overexpression of FAD mutant APP enhances Ab42 production and amyloid deposition, it suppresses axonal defects and gives mild suppression, as opposed to enhancement of other defects such as behavior.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    Tg-swAPP Prp commonly exhibited axonal blockages that were not immunoreactive for ChAT and occasionally displayed electron dense axoplasm reminiscent of axonal degeneration.

    “As previously reported (7), Tg-swAPP Prp commonly exhibited axonal blockages that were not immunoreactive for ChAT and occasionally displayed electron dense axoplasm reminiscent of axonal degeneration”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [7] Stokin, 2005, Axonopathy and transport deficits early in the pathogenesis of Alzheimer’s disease, Science source

  • May combine two claims.

    Findingown data

    Combining FAD mutant PS1 with FAD mutant APP increased Aβ42/Aβ40 ratios and enhanced amyloid deposition.

    “We found that combining FAD mutant PS1 with FAD mutant APP increased Ab42/Ab40 ratios and enhanced amyloid deposition as previously reported.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    10-11-month-old Tg-swAPP Prp mice had 2935.4+575.35 and 1561.2+166.76 fmols/mg of wet brain of formic acid extractable Aβ40 and Aβ42, respectively.

    “Specifically, 10-11-month-old Tg-swAPP Prp mice had 2935.4+ 575.35 and 1561.2 + 166.76 fmols/mg of wet brain of formic acid extractable Ab40 and Ab42, respectively.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Co-expression of FAD mutant PS1 with FAD mutant APP failed to enhance the rotarod deficit seen in Tg-swAPP PrP mice, and actually produced partial suppression of the working performance deficit.

    “Strikingly, not only did co-expression of FAD mutant PS1 with FAD mutant APP fail to enhance the deficit seen in Tg-swAPP PrP mice, but it actually produced partial suppression of the working performance deficit seen in Tg-swAPP Prp mice.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Tg-swAPP Prp; Tg-BRI-Aβ40 Prp littermates had 603+161.41 and 266.5+129.93 fmols/mg of wet brain formic acid extractable Aβ40 and Aβ42, respectively.

    “Tg-swAPP Prp ; Tg-BRI-Ab40 Prp littermates had 603 + 161.41 and 266.5 + 129.93 fmols/mg of wet brain formic acid extractable Ab40 and Ab42, respectively”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Tg-swAPP Prp, but not Tg-A246EPS1 Prp or double transgenic mice, exhibited deficits in cued conditioning compared to WT littermates, suggesting these behavioral phenotypes were not enhanced by increasing Aβ generation.

    “Tg-swAPP Prp , but not Tg-A246EPS1 Prp or Tg-swAPP Prp ; Tg-A246EPS1 Prp , mice exhibited deficits in conditioning compared to WT littermates, suggesting that these behavioral phenotypes were not enhanced by increasing Ab generation.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    CSP-immunoreactive axonal blockages are observed in larvae overexpressing FAD mutant human APP (SWE), but not in larvae expressing FAD mutant Drosophila presenilin (PsnE280A) or in larvae co-expressing FAD mutant Drosophila presenilin with FAD mutant APP (PsnE280A;SWE).

    “(A) Cysteine string protein-immunoreactive (CSP) axonal blockages are observed (arrows) in larvae overexpressing FAD mutant human APP (SWE, n ¼ 5), but not in larvae expressing FAD mutant Drosophila presenilin (PsnE280A, n ¼ 5) or in larvae co-expressing FAD mutant Drosophila presenilin with FAD mutant APP (PsnE280A;SWE, n ¼ 5, bar¼10 mm).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Average levels of APP were significantly increased after 6 h of ligation relative to unligated controls in the distal stump of 4-month-old WT and Tg-swAPP PrP mice, but not in Tg-A246EPS1 PrP and Tg-swAPP PrP;Tg-A246EPS1 PrP mice.

    “and in the distal stump of 4-month-old WT (n ¼ 6, P 0.05) and Tg-swAPP PrP (n ¼ 7, P 0.05), but not Tg-A246EPS1 PrP (n ¼ 6) and Tg-swAPP PrP ; Tg-A246EPS1 PrP (n ¼ 7).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    TUNEL analysis indicates apoptotic nuclei in larval brains expressing FAD mutant APP (SWE), but not in larval brains expressing FAD mutant Drosophila presenilin (PsnE280A) or in larval brains co-expressing FAD mutant Drosophila presenilin with FAD mutant APP (PsnE280A;SWE).

    “(C) TUNEL analysis indicates apoptotic nuclei in larval brains expressing FAD mutant APP (SWE, n ¼ 5, arrows), but not in larval brains expressing FAD mutant Drosophila presenilin (PsnE280A, n ¼ 5) or in larval brains co-expressing FAD mutant Drosophila presenilin with FAD mutant APP (PsnE280A;SWE, n ¼ 5, bar¼10 mm).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The percentage of cholinergic fibers in deep layers of the SC with varicosities of diameters 1.4-2.0 mm and 2.0-2.6 mm is increased in Tg-swAPP PrP mice, but not in WT, Tg-A246EPS1 PrP, or Tg-swAPP PrP;Tg-A246EPS1 PrP mice.

    “(b) Increased percentage of cholinergic fibers in deep layers of the SC with varicosities of diameters between 1.4 and 2.0 mm and 2.0 and 2.6 (swellings) in Tg-swAPP PrP (n ¼ 3, Ã means P 0.05), but not WT (n ¼ 3), Tg-A246EPS1 PrP (n ¼ 3) or Tg-swAPP PrP ; Tg-A246EPS1 PrP mice (n ¼ 3).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The percentage of cholinergic fibers in BN with varicosities of diameters 2.7-3.6 mm, 3.6-4.5 mm, and over 4.5 mm is increased in Tg-swAPP PrP mice, and with varicosities of 2.7-3.6 mm in Tg-A246EPS1 PrP mice, but not in WT or Tg-swAPP PrP;Tg-A246EPS1 PrP mice.

    “(D) (a) Increased percentage of cholinergic fibers in BN with varicosities of diameters between 2.7 and 3.6 mm, 3.6 and 4.5 mm and over 4.5 mm (swellings) in Tg-swAPP PrP (n ¼ 3, Ã means P 0.05) and between 2.7 and 3.6 mm (swellings) in Tg-A246EPS1 PrP (n ¼ 3, Ã means P 0.05), but not WT (n ¼ 3) or Tg-swAPP PrP ; Tg-A246EPS1 PrP mice (n ¼ 3).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Axonal blockages in baso-cortical cholinergic profiles are present in Tg-swAPP PrP and Tg-A246EPS1 PrP mice, but not in WT or Tg-swAPP PrP;Tg-A246EPS1 PrP mice.

    “Representative electron microscope images of cholinergic profiles in BN showing axonal blockages in Tg-swAPP PrP (b) and Tg-A246EPS1 PrP (c), but not WT (a) or Tg-swAPP PrP ; Tg-A246EPS1 PrP (d) mice; axonal profiles are circled in red (bar 300 nm).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In deep layers of the SC, cholinergic fiber swellings are present in Tg-swAPP PrP mice, to a lesser extent in Tg-A246EPS1 PrP and Tg-swAPP PrP;Tg-A246EPS1 PrP mice, but not in WT mice.

    “Representative light microscope images of cholinergic fibers in deep layers of the SC showing swellings (red arrows) in Tg-swAPP PrP (b), to a lesser extent in Tg-A246EPS1 PrP (c) and Tg-swAPP PrP ; Tg-A246EPS1 PrP (d), but not in WT (a) mice (bar 15 mm).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    During evaluation of cued conditioning 24 h after training, the percentage of freezing is significantly reduced in Tg-swAPP PrP mice, but not in Tg-A246EPS1 PrP or Tg-swAPP PrP;Tg-A246EPS1 PrP mice, compared with WT littermates in both genetic backgrounds.

    “Significantly reduced percentage of freezing in Tg-swAPP PrP ( Ã means P 0.05), but not Tg-A246EPS1 PrP or Tg-swAPP PrP ; Tg-A246EPS1 PrP , compared with WT littermates during evaluation of cued conditioning 24 h after training (c and d) in C57BL/6J/C3H/HeJ (c) and C57BL/ 6J (d) genetic backgrounds.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Large axonal swellings in baso-cortical cholinergic fibers are seen primarily in Tg-swAPP PrP mice, but not in WT, Tg-A246EPS1 PrP, or Tg-swAPP PrP;Tg-A246EPS1 PrP littermates.

    “Representative light microscope images of cholinergic fibers in BN showing varicosities (black arrows) in all genotypes, while large axonal swellings (red arrows) were seen primarily in Tg-swAPP PrP (b), but not WT (a), Tg-A246EPS1 PrP (c) or Tg-swAPP PrP ; Tg-A246EPS1 PrP (d) littermates (bar 15 mm).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Axonal transport in sciatic nerve ligation experiments was scanned by one investigator, then coded for genotypes and analyzed blind by another investigator who broke the codes only upon completion of the experiments.

    “Axonal transport was evaluated in sciatic nerve ligation experiments in which gels and western blots were run and scanned by one investigator, then coded for genotypes and analyzed 'blind' by another investigator who broke the codes only upon completion of the experiments.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Either the cellular location of APP processing, or the axonal defects generated by APP overexpression, are the major causes of neuronal and behavioral defects seen in mice overexpressing mutant APP.

    “Instead, we suggest that either the cellular location of APP processing, or the axonal defects generated by APP overexpression are the major causes of neuronal and behavioral defects seen in mice overexpressing mutant APP.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Expression of FAD mutant PS1 reduces the fast anterograde axonal transport of endogenous and transgenic APP, in addition to increasing Aβ42 generation.

    “Collectively, these results suggest that, in addition to increasing Ab42 generation (Supplementary Material, Fig. S10), expression of FAD mutant PS1 reduces the fast anterograde axonal transport of endogenous and transgenic APP.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    Enhancing Aβ accumulation per se does not lead to enhanced formation of axonal blockages, suggesting that the major route of generation of axonal phenotypes in APP transgenic mice is not a result of increasing levels of Aβ.

    “Thus, enhancing Ab accumulation per se does not lead to enhanced formation of axonal blockages, suggesting that the major route of generation of axonal phenotypes in APP transgenic mice is not a result of increasing levels of Ab.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Measurements of varicosity diameters and lengths were made blind to the genotypes of the sections, with codes broken only after completion of data collection.

    “These measurements were made 'blind' to the genotypes of the sections, which were coded.Codes were broken only after completion of the data collection.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Study design and conductnone given

    Mice produced for behavioral analysis were coded for their genotypes at weaning, and codes were broken only upon completion of all tasks.

    “WT, Tg-swAPP Prp , Tg-A246EPS1 Prp and Tg-swAPP Prp ; Tg-A246EPS1 Prp littermates produced for behavioral analysis were coded for their genotypes at weaning.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Aβ is sufficient, but not necessary, for the formation of neuritic defects.

    “Thus, Ab is sufficient, but as we show here, and argue above, not necessary for the formation of neuritic defects.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [6] Meyer-Luehmann, 2008, Rapid appearance and local toxicity of amyloid-beta plaques in a mouse model of Alzheimer’s disease, Nature source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    Cholinergic terminal data were collected blind by two independent observers and produced comparable final results.

    “These data were also collected 'blind' to the genotypes of the sections by two independent observers (G.B.S. and E.M.R.) and produced comparable final results.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Axonal pathology was scored blind to the genotypes by two independent observers.

    “Axonal pathology was scored 'blind' to the genotypes by two independent observers (G.B.S. and E.M.R.).”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Large diameter axonal varicosities correspond to axonal swellings, a bona fide equivalent of axonal blockages at the light microscope level.

    “Since previous work on cholinergic fibers in the BN found that large diameter axonal varicosities correspond to axonal swellings, a bona fide equivalent of axonal blockages at the light microscope level (7), we measured diameters and lengths of varicosities and inter-varicosity shafts”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [7] Stokin, 2005, Axonopathy and transport deficits early in the pathogenesis of Alzheimer’s disease, Science source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Overexpression of mutant APP or mutant PS1, but not their combined overexpression, elevates cortical ChAT activity.

    “For example, overexpression of mutant APP or mutant PS1, but not their combined overexpression, elevates cortical ChAT activity (62).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [62] Hernandez, 2001, Survival and plasticity of basal forebrain cholinergic systems in mice transgenic for presenilin-1 and amyloid precursor protein mutant genes, Neuroreport source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Experimental samples with signal intensities within the linear range were quantified by two independent investigators, one blind to the genotypes.

    “Experimental samples with signal intensities within the linear range were quantified by two independent investigators, one blind to the genotypes, using Image J (NIH) or Scion Image software (Scion Corporation).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Formation of these defects was enhanced by genetic reductions in kinesin-1 in Drosophila and in mice, where increased Aβ42/Aβ40 ratios and enhanced amyloid deposition were also observed.

    “Formation of these defects was shown to be enhanced by genetic reductions in kinesin-1 in Drosophila (29,30) and in mice, where increased Ab42/Ab40 ratios and enhanced amyloid deposition were also observed (7,57).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [7] Stokin, 2005, Axonopathy and transport deficits early in the pathogenesis of Alzheimer’s disease, Science source
    • cites [57] Holcomb, 1998, Accelerated Alzheimer-type phenotype in transgenic mice carrying both mutant amyloid precursor protein and presenilin 1 transgenes, Nat. Med. source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    With rare exceptions, one mouse per genotype per trial was tested simultaneously and the position of each mouse changed between the trial days.

    “With rare exceptions, we tested one mouse per genotype per trial simultaneously and the position of each mouse changed between the trial days.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Comparable areas of the BN were sampled with similar number of semithin and ultrathin sections from each mouse.

    “Comparable areas of the BN were sampled with similar number of semithin and ultrathin sections from each mouse.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Fusions of BRI-Aβ42 chimeras lead to synthesis and secretion of Aβ42 and amyloid deposition.

    “Previous work revealed that fusions of BRI-Ab42 chimeras lead to synthesis and secretion of Ab42 and amyloid deposition (45).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [45] McGowan, 2005, Abeta42 is essential for parenchymal and vascular amyloid deposition in mice, Neuron source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    Characterization of the Kif5B antibodies showed that these antibodies recognize primarily Kif5B (based on in vitro assays with Kif5A and Kif5C) and turned out to be exceptionally clean despite being crude sera.

    “Characterization of the Kif5B antibodies showed that these antibodies recognize primarily Kif5B (based on the in vitro assays with Kif5A and Kif5C) and turned out to be exceptionally clean despite being crude sera (38,39).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [38] Kamal, 2000, Axonal transport of amyloid precursor protein is mediated by direct binding to the kinesin light chain subunit of kinesin-I, Neuron source
    • cites [39] Kamal, 2001, Kinesin-mediated axonal transport of a membrane compartment containing beta-secretase and presenilin-1 requires APP, Nature source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    The two freezing response measurement methods are complimentary and results from both data sets were consistent with each other.

    “These two freezing response measurement methods are complimentary and since results from both data sets were consistent with each other only data obtained by visual scoring are shown.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Almost all samples were examined on multiple gels and each gel on average by three to five different exposures.

    “Almost all samples were examined on multiple gels and each gel on average by three to five different exposures.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Axonal blockages in Drosophila and mice are thought to correspond to aberrant accumulations of proteins, vesicles and organelles within axons that block or otherwise inhibit normal axonal transport.

    “Axonal blockages in Drosophila and mice are thought to correspond to aberrant accumulations of proteins, vesicles and organelles within axons that block or otherwise inhibit normal axonal transport (7,29,(48)(49)(50)(51).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [7] Stokin, 2005, Axonopathy and transport deficits early in the pathogenesis of Alzheimer’s disease, Science source
    • cites [29] Gunawardena, 2001, Disruption of axonal transport and neuronal viability by amyloid precursor protein mutations in Drosophila, Neuron source
    • cites (48)(49)(50)(51)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Quantification of APP, Kif5B and SYD was normalized for a-tubulin and myelin basic protein.

    “Quantification of APP, Kif5B and SYD was normalized for a-tubulin and myelin basic protein.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Transgenic mice overexpressing APP which lack a caspase cleavage site in the C-terminal cytoplasmic region of APP generate large amounts of Ab peptides, but do not exhibit the significant cellular, synaptic and behavioral changes seen in matched transgenic mice producing comparable levels of Ab, but in which the caspase cleavage site is intact.

    “These transgenic mice generate large amounts of Ab peptides, but they do not exhibit the significant cellular, synaptic and behavioral changes seen in matched transgenic mice producing comparable levels of Ab, but in which the caspase cleavage site is intact(63).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [63] Galvan, 2006, Reversal of Alzheimer’s-like pathology and behavior in human APP transgenic mice by mutation of Asp664, Proc. Natl Acad. Sci. USA source

  • May combine two claims. The quote only partly states this claim.

    Premisecitation

    When Tg-BRI-Aβ42 Prp mice were crossed with Tg-swAPP Prp, the double transgenic mice had significantly increased RIPA-insoluble formic acid extracted Aβ40 and Aβ42 as well as enhanced amyloid deposition in several brain areas including BN compared with single transgenic Tg-swAPP Prp, Tg-BRI-Aβ40 Prp and BRI-Tg-Aβ42 Prp or Tg-swAPP Prp; Tg-BRI-Aβ40 Prp double transgenic littermates.

    “In particular, when Tg-BRI-Ab42 Prp mice were crossed with Tg-swAPP Prp (53), the double transgenic Tg-swAPP Prp ; Tg-BRI-Ab42 Prp mice had significantly increased RIPA-insoluble formic acid extracted Ab40 and Ab42 as well as enhanced amyloid deposition in several brain areas including BN compared with single transgenic Tg-swAPP Prp”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [45] McGowan, 2005, Abeta42 is essential for parenchymal and vascular amyloid deposition in mice, Neuron source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Amyloid deposition occurs prior to neuritic defects.

    “A recent in vivo dynamics study of cortical amyloid plaque formation found amyloid deposition prior to neuritic defects (6).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [6] Meyer-Luehmann, 2008, Rapid appearance and local toxicity of amyloid-beta plaques in a mouse model of Alzheimer’s disease, Nature source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Genetic reductions in kinesin-I also enhanced aberrant Aβ generation and amyloid deposition.

    “These reductions also enhanced aberrant Ab generation and amyloid deposition (7).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [7] Stokin, 2005, Axonopathy and transport deficits early in the pathogenesis of Alzheimer’s disease, Science source
47 of 47

  • The paper relies on this without support.

    Directly varying APP levels alters APP domains in addition to Aβ.

    “Because directly varying APP levels also alters APP domains in addition to Ab, we perturbed Ab generation selectively by combining APP transgenes in Drosophila and mice with presenilin-1 (PS1) transgenes harboring mutations that cause familial AD (FAD).”
1 of 1

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Mutant PS1 alone is said not to produce axonal pathology despite a reported increase in swellings

    Minor

    The discussion says transgenic FAD PS1 mutations cannot produce axonal pathology on their own, but the Figure 1 caption reports a significant increase in axonal swellings in mice expressing mutant PS1 alone.

1 of 1

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Authors
Stokin, G. B., Almenar-Queralt, A., Gunawardena, S., Rodrigues, E. M., Falzone, T., Kim, J., Lillo, C., Mount, S. L., Roberts, E. A., McGowan, E., Williams, D. S., & Goldstein, L. S. B.
Affiliations
  • Howard Hughes Medical Institute (US)
  • Mayo Clinic (US)
  • University of California San Diego (US)
Corresponding author
Goldstein, Lawrence S.B.
ORCID
Venue
Human Molecular Genetics
Publisher
Oxford University Press (OUP)
Published
2008-08-11
Volume
17
Issue
22
Pages
3474-3486
ISSN
  • 0964-6906 (ISSN-L)
  • 1460-2083
DOI
10.1093/hmg/ddn240
PMC
PMC2722897
OpenAlex
W2118694086
Semantic Scholar
13d2199f0230c6ed399feb9764abbd4fb4a26413
Cited by
72
References
86
Citations by year
2026: 1 · 2025: 1 · 2024: 2 · 2023: 4 · 2022: 2 · 2021: 3 · 2020: 3 · 2019: 2 · 2018: 4 · 2016: 4 · 2015: 5 · 2014: 5 · 2013: 8 · 2012: 6
FWCI
4.42
Type
journal article
Language
en
Open access
Locations
  • Human Molecular Genetics (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion)
Funders
  • Howard Hughes Medical Institute
  • Ellison Medical Foundation
  • National Institutes of Health (5r01ey013408-11, EY13408)
  • U.S. Public Health Service (AGO22595)
  • National Institute on Aging
  • National Eye Institute (R01 EY007042)
  • National Institute of General Medical Sciences (GM 35252, R01GM035252)
Topics
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
Keywords
amyloid precursor protein, axonal transport, amyloid-beta, Alzheimer's disease, presenilin 1, familial Alzheimer's disease, APP overexpression, neuronal apoptosis, Aβ42/Aβ40 ratio, amyloid deposition, axonopathy
MeSH terms
Alzheimer Disease, Analysis of Variance, Animals, Axons, Axonal Transport, Behavior, Animal, Drosophila, Fear, Female, Humans, Immunohistochemistry, Male, Mice, Transgenic, Microscopy, Electron, Amyloid beta-Peptides, Amyloid beta-Protein Precursor, Transgenes, In Situ Nick-End Labeling, Mice, Presenilins, Cerebrum

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-17.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-17.

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Statistics and arithmetic are recomputed, not judged.

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