Targeting of nonlipidated, aggregated apoE with antibodies inhibits amyloid accumulation
Fan Liao, … , Ryan J. Watts, David M. Holtzman
Fan Liao, … , Ryan J. Watts, David M. Holtzman
Published March 30, 2018
Citation Information: J Clin Invest. 2018;128(5):2144-2155. https://doi.org/10.1172/JCI96429.
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Research Article Neuroscience

Targeting of nonlipidated, aggregated apoE with antibodies inhibits amyloid accumulation

Abstract

The apolipoprotein E E4 allele of the APOE gene is the strongest genetic factor for late-onset Alzheimer disease (LOAD). There is compelling evidence that apoE influences Alzheimer disease (AD) in large part by affecting amyloid β (Aβ) aggregation and clearance; however, the molecular mechanism underlying these findings remains largely unknown. Herein, we tested whether anti–human apoE antibodies can decrease Aβ pathology in mice producing both human Aβ and apoE4, and investigated the mechanism underlying these effects. We utilized APPPS1-21 mice crossed to apoE4-knockin mice expressing human apoE4 (APPPS1-21/APOE4). We discovered an anti–human apoE antibody, anti–human apoE 4 (HAE-4), that specifically recognizes human apoE4 and apoE3 and preferentially binds nonlipidated, aggregated apoE over the lipidated apoE found in circulation. HAE-4 also binds to apoE in amyloid plaques in unfixed brain sections and in living APPPS1-21/APOE4 mice. When delivered centrally or by peripheral injection, HAE-4 reduced Aβ deposition in APPPS1-21/APOE4 mice. Using adeno-associated virus to express 2 different full-length anti–apoE antibodies in the brain, we found that HAE antibodies decreased amyloid accumulation, which was dependent on Fcγ receptor function. These data support the hypothesis that a primary mechanism for apoE-mediated plaque formation may be a result of apoE aggregation, as preferentially targeting apoE aggregates with therapeutic antibodies reduces Aβ pathology and may represent a selective approach to treat AD.

Authors

Fan Liao, Aimin Li, Monica Xiong, Nga Bien-Ly, Hong Jiang, Yin Zhang, Mary Beth Finn, Rosa Hoyle, Jennifer Keyser, Katheryn B. Lefton, Grace O. Robinson, Javier Remolina Serrano, Adam P. Silverman, Jing L. Guo, Jennifer Getz, Kirk Henne, Cheryl E.G. Leyns, Gilbert Gallardo, Jason D. Ulrich, Patrick M. Sullivan, Eli Paul Lerner, Eloise Hudry, Zachary K. Sweeney, Mark S. Dennis, Bradley T. Hyman, Ryan J. Watts, David M. Holtzman

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Figure 4

HAE-1 and HAE-4 staining of amyloid plaques in unfixed mouse brain sections and specificity for heat-induced aggregates of apoE4.

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HAE-1 and HAE-4 staining of amyloid plaques in unfixed mouse brain secti...
(A) Unfixed frozen brain sections from APPPS1-21/APOE4 or APPPS1-21/EKO mice were stained with anti–Aβ antibody HJ3.4 and anti–apoE antibodies HAE-1 and HAE-4. Scale bar = 400 μm. (B) Binding of HAE-1, HAE-2, and HAE-4 to untreated recombinant apoE4 (untreated) or apoE4 that had been incubated at 40°C for 24 hours (40°C). (C) Incubation of apoE4 at 40°C for 24 hours results in the formation of aggregates recovered in the pellet fraction following ultracentrifugation at 186,000 g for 1 hour. Lane 1, untreated apoE4. Lane 2, apoE4 that had been incubated at 40°C for 24 hours. Supernatant (S) and pellet (P) from ultracentrifugation were resolved on SDS-PAGE and stained by Coomassie blue. (D) Binding of HAE-4 to different preparations of apoE4 immobilized at the same concentration (0.5 μg/ml) on the ELISA plate. Sup of untreated: supernatant fraction of untreated apoE4 from ultracentrifugation. Sup/Pel of 24 hours 40°C: supernatant/pellet fraction of apoE4 incubated at 40°C for 24 hours. (E) Binding of HAE-4 to untreated apoE4 and apoE4 that had been incubated at 40°C before and after denaturation by 1% SDS or 4 M guanidine HCl.