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Murine Aβ over-production produces diffuse and compact Alzheimer-type amyloid deposits.

Xu G, Ran Y, Fromholt SE, Fu C, Yachnis AT, Golde TE, Borchelt DR - Acta Neuropathol Commun (2015)

Bottom Line: Transgenic overexpression of amyloid precursor protein (APP) genes that are either entirely human in sequence or have humanized Aβ sequences can produce Alzheimer-type amyloidosis in mice, provided the transgenes also encode mutations linked to familial Alzheimer's Disease (FAD).Both lines of mice that produce mouse Aβ develop amyloid deposits, with the moAPPswe/PS1dE9 micedeveloping extracellular compact, cored, neuritic deposits that primarily localize to white matter tracts andmeningial layers, whereas the tet.moAPPsi mice developed extracellular diffuse cortical/hippocampal deposits distributed throughout the parenchyma.These findings demonstrate that murine Aβ peptides have the capacity to produce amyloid deposits that are morphologically similar to deposits found in human AD provided the murine APP gene harbors mutations linked to human FAD.

View Article: PubMed Central - PubMed

Affiliation: Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA.

ABSTRACT

Introduction: Transgenic overexpression of amyloid precursor protein (APP) genes that are either entirely human in sequence or have humanized Aβ sequences can produce Alzheimer-type amyloidosis in mice, provided the transgenes also encode mutations linked to familial Alzheimer's Disease (FAD). Although transgenic mice have been produced that overexpress wild-type mouse APP, no mice have been generated that express mouse APP with FAD mutations. Here we describe two different versions of such mice that produce amyloid deposits consisting of entirely of mouse Aβ peptides. One line of mice co-expresses mouse APP-Swedish (moAPPswe) with a human presenilin exon-9 deleted variant (PS1dE9) and another line expresses mouse APP-Swedish/Indiana (APPsi) using tetracycline-regulated vectors (tet.moAPPsi).

Results: Both lines of mice that produce mouse Aβ develop amyloid deposits, with the moAPPswe/PS1dE9 micedeveloping extracellular compact, cored, neuritic deposits that primarily localize to white matter tracts andmeningial layers, whereas the tet.moAPPsi mice developed extracellular diffuse cortical/hippocampal deposits distributed throughout the parenchyma.

Conclusions: These findings demonstrate that murine Aβ peptides have the capacity to produce amyloid deposits that are morphologically similar to deposits found in human AD provided the murine APP gene harbors mutations linked to human FAD.

No MeSH data available.


Related in: MedlinePlus

Analysis of Aβ peptides produced by mouse N2a cells transiently expressing mouse and MoHu chimeric APP genes. a Examples of mass spectrometry data from the analysis of cell culture medium of mouse N2a cells transiently transfected with expression plasmids encoding moAPP-WT, moAPPswe, MoHuAPP-WT, and MoHuAPPswe. The Aβ in the medium was immunoprecipitated with the monoclonal antibody 4G8 and then analyzed by mass spectrometry. The positions of mouse and human Aβ40 (mAβ40 and hAβ40) are noted on the spectrum traces. b Analysis of data from repeated experiments (n = 3) demonstrated that the Swedish mutations in mouse APP shift cleavage to produce a greater amount of Aβ1-40 over Aβ11-40. Standard deviation (SD) was shown at the error bars
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Fig2: Analysis of Aβ peptides produced by mouse N2a cells transiently expressing mouse and MoHu chimeric APP genes. a Examples of mass spectrometry data from the analysis of cell culture medium of mouse N2a cells transiently transfected with expression plasmids encoding moAPP-WT, moAPPswe, MoHuAPP-WT, and MoHuAPPswe. The Aβ in the medium was immunoprecipitated with the monoclonal antibody 4G8 and then analyzed by mass spectrometry. The positions of mouse and human Aβ40 (mAβ40 and hAβ40) are noted on the spectrum traces. b Analysis of data from repeated experiments (n = 3) demonstrated that the Swedish mutations in mouse APP shift cleavage to produce a greater amount of Aβ1-40 over Aβ11-40. Standard deviation (SD) was shown at the error bars

Mentions: Prior studies of APP processing in murine cells have demonstrated that murine BACE1 preferentially cleaves wild-type mouse APP at the +11 residue of Aβ [6]. In human cells, human WT APP is also preferentially cleaved at residue +11, but the Swedish double mutations in APP shift cleavage to the +1 residue [6]. To determine whether introducing the Swedish mutations into murine APP produces the same effects, we transfected mouse N2a cells with expression vectors for moAPP695, with and without the Swedish mutation, and analyzed the Aβx-40 peptides produced by immunoprecipitation and mass spectrometry (Fig. 2). For comparison we also expressed WT and Swedish variants of the chimeric MoHuAPP695 cDNAs used previously to produce transgenic mice [3]. Both the moAPP695 and MoHuAPP695 proteins with WT sequences produced primarily Aβ11-40 (Fig. 2a and b), whereas both of these proteins encoding the Swedish mutation [K595N,M596L] produced primarily Aβ1-40 (Fig. 2a and b). Aβ42 levels were too low to quantify accurately in this system, but there was trend of Aβ42 increasing in the N2a cells expressing APP with Swedish mutation.Fig. 2


Murine Aβ over-production produces diffuse and compact Alzheimer-type amyloid deposits.

Xu G, Ran Y, Fromholt SE, Fu C, Yachnis AT, Golde TE, Borchelt DR - Acta Neuropathol Commun (2015)

Analysis of Aβ peptides produced by mouse N2a cells transiently expressing mouse and MoHu chimeric APP genes. a Examples of mass spectrometry data from the analysis of cell culture medium of mouse N2a cells transiently transfected with expression plasmids encoding moAPP-WT, moAPPswe, MoHuAPP-WT, and MoHuAPPswe. The Aβ in the medium was immunoprecipitated with the monoclonal antibody 4G8 and then analyzed by mass spectrometry. The positions of mouse and human Aβ40 (mAβ40 and hAβ40) are noted on the spectrum traces. b Analysis of data from repeated experiments (n = 3) demonstrated that the Swedish mutations in mouse APP shift cleavage to produce a greater amount of Aβ1-40 over Aβ11-40. Standard deviation (SD) was shown at the error bars
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4644287&req=5

Fig2: Analysis of Aβ peptides produced by mouse N2a cells transiently expressing mouse and MoHu chimeric APP genes. a Examples of mass spectrometry data from the analysis of cell culture medium of mouse N2a cells transiently transfected with expression plasmids encoding moAPP-WT, moAPPswe, MoHuAPP-WT, and MoHuAPPswe. The Aβ in the medium was immunoprecipitated with the monoclonal antibody 4G8 and then analyzed by mass spectrometry. The positions of mouse and human Aβ40 (mAβ40 and hAβ40) are noted on the spectrum traces. b Analysis of data from repeated experiments (n = 3) demonstrated that the Swedish mutations in mouse APP shift cleavage to produce a greater amount of Aβ1-40 over Aβ11-40. Standard deviation (SD) was shown at the error bars
Mentions: Prior studies of APP processing in murine cells have demonstrated that murine BACE1 preferentially cleaves wild-type mouse APP at the +11 residue of Aβ [6]. In human cells, human WT APP is also preferentially cleaved at residue +11, but the Swedish double mutations in APP shift cleavage to the +1 residue [6]. To determine whether introducing the Swedish mutations into murine APP produces the same effects, we transfected mouse N2a cells with expression vectors for moAPP695, with and without the Swedish mutation, and analyzed the Aβx-40 peptides produced by immunoprecipitation and mass spectrometry (Fig. 2). For comparison we also expressed WT and Swedish variants of the chimeric MoHuAPP695 cDNAs used previously to produce transgenic mice [3]. Both the moAPP695 and MoHuAPP695 proteins with WT sequences produced primarily Aβ11-40 (Fig. 2a and b), whereas both of these proteins encoding the Swedish mutation [K595N,M596L] produced primarily Aβ1-40 (Fig. 2a and b). Aβ42 levels were too low to quantify accurately in this system, but there was trend of Aβ42 increasing in the N2a cells expressing APP with Swedish mutation.Fig. 2

Bottom Line: Transgenic overexpression of amyloid precursor protein (APP) genes that are either entirely human in sequence or have humanized Aβ sequences can produce Alzheimer-type amyloidosis in mice, provided the transgenes also encode mutations linked to familial Alzheimer's Disease (FAD).Both lines of mice that produce mouse Aβ develop amyloid deposits, with the moAPPswe/PS1dE9 micedeveloping extracellular compact, cored, neuritic deposits that primarily localize to white matter tracts andmeningial layers, whereas the tet.moAPPsi mice developed extracellular diffuse cortical/hippocampal deposits distributed throughout the parenchyma.These findings demonstrate that murine Aβ peptides have the capacity to produce amyloid deposits that are morphologically similar to deposits found in human AD provided the murine APP gene harbors mutations linked to human FAD.

View Article: PubMed Central - PubMed

Affiliation: Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, 32610, USA.

ABSTRACT

Introduction: Transgenic overexpression of amyloid precursor protein (APP) genes that are either entirely human in sequence or have humanized Aβ sequences can produce Alzheimer-type amyloidosis in mice, provided the transgenes also encode mutations linked to familial Alzheimer's Disease (FAD). Although transgenic mice have been produced that overexpress wild-type mouse APP, no mice have been generated that express mouse APP with FAD mutations. Here we describe two different versions of such mice that produce amyloid deposits consisting of entirely of mouse Aβ peptides. One line of mice co-expresses mouse APP-Swedish (moAPPswe) with a human presenilin exon-9 deleted variant (PS1dE9) and another line expresses mouse APP-Swedish/Indiana (APPsi) using tetracycline-regulated vectors (tet.moAPPsi).

Results: Both lines of mice that produce mouse Aβ develop amyloid deposits, with the moAPPswe/PS1dE9 micedeveloping extracellular compact, cored, neuritic deposits that primarily localize to white matter tracts andmeningial layers, whereas the tet.moAPPsi mice developed extracellular diffuse cortical/hippocampal deposits distributed throughout the parenchyma.

Conclusions: These findings demonstrate that murine Aβ peptides have the capacity to produce amyloid deposits that are morphologically similar to deposits found in human AD provided the murine APP gene harbors mutations linked to human FAD.

No MeSH data available.


Related in: MedlinePlus