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 3

Binding profile of HAE-1, HAE-2, and HAE-4 with lipidated apoE.

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Binding profile of HAE-1, HAE-2, and HAE-4 with lipidated apoE. (A and B...
(A and B) Antibody binding to mouse plasma from EKO, APOE2, APOE3, and APOE4 mice was coated onto the plates. Titrations of chi–HAE-2 and chi–HAE-4 were incubated and antibody that was captured was detected with HRP-goat anti–human IgG antibody. (C and D) HAE-2 or HAE-4 was immobilized on the plate followed by the addition of plasma from mice with different genotypes. apoE, captured from the plasma, was detected with HRP-goat polyclonal anti-apoE. (E) Plasma inhibition of anti-apoE binding to immobilized recombinant apoE4. HAE-1 (50 nM), HAE-2 (4 nM), and HAE-4 (50 nM) were preincubated with serially diluted plasma from APOE4-KI mice and then added to plates coated with recombinant apoE4. The HAE antibodies bound to the plates were detected with HRP-goat anti–mouse IgG antibodies. (F) Plasma antibody concentrations of HAE-4 or control IgG following i.p. injection into APOE4-KI or EKO mice. HAE-4 was dosed at 2 mg/kg, 10 mg/kg, and 50 mg/kg and plasma samples were collected by submandibular puncture. Control murine IgG2a (msIgG2a) was anti-Her2 and dosed at 10 mg/kg. Quantification of dosed antibodies in plasma was by antigen-capture ELISA using coated recombinant apoE4 to detect HAE-4, with recombinant Her2 used to detect the control IgG.