- Email: [email protected]
Predicting in vivo BACE inhibitor efficacy: Are human iPS-derived neurons superior?
P810
Poster Presentations: P4
Computational chemistry methods have been applied to investigate the observed decrease in affinity. Results: As expected, the Swedish mutation peptide showed the highest maximum velocity, while the KM value was comparable to that for the wild-type substrate. The A673T mutation substrate yielded a Vmax value in the same range as the wild-type, but the KM value was increased by 50 fold. These results suggest the turnover rate of the enzyme-peptide complex is not affected by the mutation on the peptide. However, interpreting KM as a surrogate for affinity, the mutation reduces the affinity of the substrate for the enzyme. Preliminary modelingresults indicate that suboptimal interaction between BACE and the T673 hydroxyl group, which do not offset its increase desolvation, might be one of the reasons affecting the free energy of binding of the mutant. We also confirmed previous observations that in cells overexpressing APP A673T, soluble APP beta (sAPPb) secretion, primary product of BACE1 cleavage, is reduced by 50% compared to cells overexpressing the wild type construct. Conclusions: Taken together, this data suggest that a reduction of BACE affinity for this mutated APP explains how it may protect against Alzheimer’s disease. Thus providing strong evidence that reducing BACE activity by inhibitors may be beneficial for the treatment of AD.
P4-289
NORMAL HEALTHY DONORS POSSESS PLASMA IGG REACTIVE TO A NEUTRALIZING EPITOPE FOR TOXIC AND AMYLOID-SEEDING BETAAMYLOID OLIGOMERS
Ebrima Gibbs1, Judith Silverman1, Claudia Balducci2, Jing Wang3, Hui Chen4, Marni Uger5, Andrea Masi6, Valeriy Ostapchenko7, Marco Prado8, Weihong Song1, Gianluigi Forloni9, Cheryl Wellington10, Laura Saward6, Neil Cashman1, 1University of British Columbia, Vancouver, British Columbia, Canada; 2Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy; 3University of British Coumbia, Vancouver, British Columbia, Canada; 4Amorfix Life Sciences, Mississauga, Ontario, Canada; 5Amorfix Life Sciences Ltd., Mississauga, Ontario, Canada; 6Cangene Corporation, Winnipeg, Manitoba, Canada; 7University of Western Ontario, London, Ontario, Canada; 8University of Western Ontario, London, Ontario, Canada; 9Istituto di Ricerche Farmacologiche, Milano, Italy; 10The University of British Columbia, Vancouver, British Columbia, Canada. Contact e-mail: [email protected] Background: Oligomers of amyloid-b (Ab) peptide are implicated in Alzheimer’s disease (AD) synaptic dysfunction, tau phosphorylation and neurofibrillary tangle deposition, neuronal cell death and regional spread of Ab amyloidosis in the brain. We have identified an immunological epitope unique to Ab oligomers comprising the structurally constrained tripeptide cyclized serine-asparagine-lysine (cSNK).We have reported that the mouse cSNK-specific IgG1 monoclonal antibody 5E3 recognizes synthetic and AD brain-derived Ab oligomers of 45-55 kDa, and blocks neurotoxicity and Ab(1-42) oligomer growth in vitro 1. Methods: The in vivo activity of 5E3 on neurotoxicity/synaptotoxicity was evaluated by novel object recognition (NOR) test performed in C57BL/6 wild-type mice intraventricularly co-injected 2 hours earlier with antibody combined with synthetic Ab(1-42) oligomers 2. P urified IgG from young healthy donors were assayed for cSNK and synthetic Ab(1-42) oligomers using Biacore TM 1 and MagPlex TM5 immunoassays 1,3. Results: Preincubation with the monoclonal 5E3, but not control IgG1, effectively abrogated the acute NOR deficit induced by injection of A b(1-42) oligomers (p<0.01); no NOR deficit was observed on infusion of 5E3 antibody alone. MagPlex TM and Biacore TM immunoassays revealed cSNK IgG in young healthy donors, which were strongly correlated (Pearson test p<0.005). Biacore TM revealed strong correlation of IgG binding to cSNK peptide and A b(1-42) oligomers (Pearson test p<0.001). cSNK IgG was primarily IgG1 subclass, w 500 nM affinity for A b(1-42) oligomers. Conclusions: The data are consistent with the cSNK defining a "neutralizing epitope" for those Ab oligomers triggering neurotoxicity/synaptotoxicity and oligomer propagation. Natural or engineered antibodies against cSNK may have efficacy as an AD passive immunotherapy, and cSNK as a prophylactic vaccine target for populations at
high-risk for AD. 1) Silverman et al. Alz Demen 2012; 8 suppl.04-06-03. 2) Balducci et al. Proc Natl Acad Sci U S A. 2010; 107:2295-300. 3) Toth et al Alz Demen, 2012; 8 suppl.P1-228. P4-290
NOVEL FUSION PROTEIN BIVALENT FOR A GENERAL AMYLOID INTERACTION MOTIF REDUCES BETA-AMYLOID AGGREGATES IN TRANSGENIC MICE
Jonathan Levenson1, Eva Asp1, Maria Becker2, Rajaraman Krishnan1, Eliezer Masliah3, Elliott Mufson4, Muhammad Nadeem5, Sylvia Perez5, Ming Proschitsky1, Edward Rockenstein3, Haim Tsubery6, Kimberley Gannon1, 1NeuroPhage Pharmaceuticals, Cambridge, Massachusetts, United States; 2Tel Aviv University, Tel Aviv, Israel; 3 University of California San Diego, La Jolla, California, United States; 4 Rush University, Chicago, Illinois, United States; 5Rush University Medical Center, Chicago, Illinois, United States; 6Tel Aviv University, Tel Aviv, Israel. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is characterized by both Amyloid b (Ab) plaque deposition and intracellular neurofibrillary tangles accompanied by progressive cognitive decline. We have shown that NPT002 (filamentous bacteriophage M13) dose-dependently clears Ab plaques and restores normal cognitive performance in aged Tg2576 mice. Recently, we isolated the protein motif from NPT002 responsible for the amyloid-interacting activity, which we call the generic amyloid interacting motif or GAIM. The present study was conducted to evaluate whether fusion proteins bivalent for GAIM were able to clear b-amyloid aggregates in transgenic Alzheimer’s mouse models. Methods: In the present study, we administered test article or control treatment via a single intra-hippocampal 2mL injection per hemisphere (7-8mg of protein per injection). Mice used for these studies included 17-19 month old male Tg2576 mice and 17-19 month old male & female 3xTg mice. Animals were sacrificed 7 days post-treatment. Paraformaldehyde-fixed brains were serially sectioned and analyzed for Ab load in the hippocampus and surrounding cortical areas by ThioS fluorescence and anti-amyloid antibody staining (82E1). Neuro-inflammation was monitored by antibody staining for Iba1 and GFAP. Synaptic density was assessed by antibody staining for synaptophysin (SY38). Systemic administration of NPT088 was via intraperitoneal injection at 10mg/kg. Results: Intrahippocampal injection of either NPT014 (human IgG 4 -Fc-GAIM) or NPT088 (human IgG 1 -Fc-GAIM) into aged Tg2576 mice resulted in significantly lower b-amyloid plaque in hippocampus and surrounding neocortex 7 days after treatment as measured by either 82E1 or ThioS. The decrease in b-amyloid was accompanied by significant increases in Iba-1 and synaptophysin. GFAP and Perl’s Prussian Blue staining was unaffected by treatment. Similar to observations in aged Tg2576 mice, intra-hippocampal injection of NPT088 into aged 3xTg mice resulted in significant decreases in b-amyloid in the hippocampus. The timing and magnitude of the effects of NPT088 and NPT014 on b-amyloid were similar to previous studies with NPT002. Moreover, acute systemic administration of NPT088 to wt mice produced brain penetration. Conclusions: NPT088 and NPT014 safely reduced b-amyloid plaque and increased synaptic density within 7 days of direct-to-brain administration in transgenic mouse models. These data support the use of GAIM-containing molecules as a novel therapeutic approach for reducing Ab plaque. P4-291
PREDICTING IN VIVO BACE INHIBITOR EFFICACY: ARE HUMAN IPS-DERIVED NEURONS SUPERIOR?
Christine Oborski1, Sandra Engle2, Charles Nolan3, Yao Zhang1, Leslie Pustilnik2, Stephen Noell2, Ashley Robshaw1, Kevin Atchison1, Cheng Chang1, Yasong Lu1, Kewa Mou1, Michael Brodney1, David Riddell1, 1Pfizer Inc., Cambridge, Massachusetts, United States; 2 Pfizer Inc., Groton, Connecticut, United States; 3Pfizer Inc., Cambridge, Massachusetts, United States. Contact e-mail: christine.e.oborski@pfizer. com Background: BACE is the first enzyme involved in the sequential cleavage of APP leading to b -amyloid (A b) generation. The presence of A b in
Poster Presentations: P4 critical brain regions is considered to be a causative factor in the cognitive decline and neuronal degeneration associated with Alzheimer’s disease (AD). Thus, reducing levels of toxic A b species by inhibiting BACE may be a viable therapeutic strategy for the treatment of AD. Effectively selecting BACE inhibitors for in vivo profiling requires high confidence in the translatability of in vitro potency. Human iPS-derived neurons, which more closely represent human neurons, have been proposed to be a superior cellular model for translating in vitro potency to in vivo (and later clinical) efficacy. Methods: BACE inhibitors representing 3 chemical series were chosen for profiling in a soluble enzyme assay, an APP over-expressing human H4 neuroglioma cell line, a rodent primary neuronal culture, and in human iPS-derived neurons. Our human iPS line was derived from adult non-diseased fibroblasts that were reprogrammed into GABAergic neurons. IC50 correlations for A b lowering were built to compare potency across these assays. Additionally, wild-type 129/SVE mice were dosed with several of these BACE inhibitors to establish the in vivo brain IC50 for A b. For all assays, in vitro -to- in vivo correlations (IVIVCs) of in vitro IC50 values and in vivo IC50 values were generated. Results: We report a high correlation in BACE inhibitor potency between all the in vitro assays examined, including the iPS-derived neurons. Additionally, IVIVCs for the various in vitro assays described translate well to in vivo rodent efficacy. Conclusions: Selecting appropriate chemical matter for in vivo profiling is essential for efficient drug discovery. While the non-diseased human iPS-derived neurons that we tested are more representative of human neurons than the other assay models examined, they do not provide any distinct advantage in translating in vitro potency to in vivo efficacy and thus do not appear to represent a superior translatable cellular model for screening. It remains to be seen if iPSderived neurons from AD patients offer any advantage in screening for Alzheimer’s disease therapeutics.
P4-292
MULTITARGET STRATEGY OF TRADITIONAL CHINESE MEDICINE IN TREATMENT OF ALZHEIMER’S DISEASE
Lin Li1, Lan Zhang1, Ruyi Zhang1, Rong Wang2, 1Xuanwu Hospital of Capital Medical University, Beijing, China; 2Xuanwu Hospital of Capital Medical University, Beijing, China. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is a multifactorial complex disease. The failure of recent development of AD therapeutic agents in clinical trials is partly due to their single-target or single-pathway effect. Methods: We have committed to the research of traditional Chinese medicine in treatment of AD, and have developed two new drugs: Shenwu capsule (SW) composed of 6 kinds of traditional Chinese herbs, and Tetrahydroxystilbene glucoside (TSG) extracted from Polygonum multiflorum. Results: Our studies found that SW and TSG significantly improved learning-memory ability in 7 kinds of AD-like animal models, and their action mechanisms including: (1) increased the ratio of cholinacetyl-transfetase (ChAT)/cholinesterase (AchE); (2) decreased the number of amyloid plaques and the content of Ab, and inhibited the expression of b-secretase or presenilin-1; (3) inhibited a-synuclein mRNA expression, protein expression and aggregation, and activated ubiquitin-proteasome system; (4) increased the expression of protein phosphortase 2A (PP2A), inhibited hyperphosphorylation of tau protein, and protected cytoskeleton; (5) inhibited microglial activation, and decreased the content of proinflammatory cytokine TNF-a and IL-1b; (6) enhanced mitochondrial function, inhibited oxidative stress, and decreased neuron apoptosis; (7) elevated the expression of endogenous neurotrophic factor NGF and BDNF and their receptors, and activated neuron survival signal transduction pathway; (8) increased synaptic plasticity by enhancing the long-term potentiation, elevated the number of synapses, and increased the expression of synaptophysin. Conclusions: The results demonstrated that SW and TSG exerted their therapeutic effects on multitargets and multi-pathways in the complex pathogenesis of AD, especially had both neuroprotective effect and neurotrophic effect, suggesting that these drugs may be beneficial to the early intervention and delaying the progression of AD. Now SW has completed phase III clinical trial for the
P811
treatment of AD and mild cognitive impairment (MCI), and obtained good therapeutic effects; the phase II clinical trial for the treatment of AD is underway.
P4-293
STATIN EXPOSURE AND STRUCTURAL INTEGRITY MEASURES IN THE BRAIN OF OLDER ADULTS IN THE HEALTH ABC STUDY
Neelesh Nadkarni1, Subashan Perera1, Joseph Hanlon1, Stephanie Studenski1, Marshall Elam2, Tamara Harris3, Stephen Kritchevsky4, Kristine Yaffe5, Anne Newman6, Caterina Rosano1, 1 University of Pittsburgh, Pittsburgh, Pennsylvania, United States; 2 University of Tennessee Health Sciences Center, Memphis, Tennessee, United States; 3NIA, Bethesda, Maryland, United States; 4Wake Forest University, Winston-Salem, North Carolina, United States; 5University of California San Francisco, San Francisco, California, United States; 6 University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, United States. Contact e-mail: [email protected] Background: Pleotropic effects of statins are purported to benefit Alzheimer’s disease and cerebrovascular. We hypothesized that these effects could reflect as "superior" measures of brain structural integrity in statin exposed individuals, particularly in those with suboptimal performance on cognitive screening tools. Furthermore, these statin effects would be strongest in subcortical regions that are most susceptible to small-vessel disease. Methods: In 295 participants enrolled in the Health ABC Study,we identified statin exposure from medication-use data and stratified thier cognitive performance by tertiles of the Modified Mini-Mental Status Examination scores (3MS) recorded in 2004-2005. We extractedneuroimaging data from 2007-2008 and quantified integrity of brain white (WM) and gray matter (GM) and tracts of interest (anterior thalamic radiation (ATR), superior longitudinal fasciculi (SLF), corpus callosum (frontal (CCF), occipital (CCO)) using fractional anisotropy (FA), white matter hyperintensities volumes (WMHv), peak-height magnetization transfer ratio (phMTR) and mean diffusivity (MD) where applicable. We fitted two-way AN(C)OVA models to brain measures with statin exposure, 3MS tertiles and interaction; and performed stratified comparisons for statin exposure within 3MS tertiles adjusting for covariates (age, gender, race, education, coronary heart disease, diabetes and stroke). Results: Mean age of the sample was 80.1 years (58% female, 59% Caucasian, 86% with at least high-school education). There were no demographic differences in statin exposed (n¼106) and non-exposed (n¼185) groups. Statin exposure X 3MS interaction, adjusted for covariates, was significant for total WMHv (p¼0.02) and FA for whole WM (p¼0.01) but not for whole brain phMTR (p¼0.7) or MD for whole GM (p¼0.1), therefore justifyingstratified analysis by 3MS tertiles. Statin exposed participants in the lowest tertile of 3MS scores (86.3565.76) had lower total WMHv (p¼0.005) and lower WMHv in ATR (p¼0.044), SLF (p¼0.035), CCO (p¼0.002) and CCF (p¼0.016), and, higher FA in WM (p¼0.004), SLF (p¼0.005) and ATR (p¼0.033). The differences in WMHv in the CCO (p¼0.006) and CCF (p¼0.023), and, FA of WM (p¼0.005), ATR (p¼0.016) and SLF (p¼0.014) remained significant after adjustingforconfounders. There were no significant differences in the other 3MS tertiles (94.6361.16 and 98.3461.14). Conclusions: Statins may be associated with white matter integrity in older adults with suboptimal cognitive performance.
P4-294
GAMMA-SECRETASE AS A TARGET FOR ALZHEIMER’S DISEASE THERAPY: SMALLMOLECULE DEVELOPMENT
Corinne Augelli-Szafran1, Katherine Brogan2, Cuiman Cai1, Jian Chen3, Yongli Gu4, Dennis Selkoe5, Han-Xun Wei3, Michael Wolfe6, Jing Zhang1, 1 Laboratory for Experimental Alzheimer Drugs (LEAD), Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States; 2Laboratory for Experimental Alzheimer Drugs (LEAD),
Poster Presentations: P4
Computational chemistry methods have been applied to investigate the observed decrease in affinity. Results: As expected, the Swedish mutation peptide showed the highest maximum velocity, while the KM value was comparable to that for the wild-type substrate. The A673T mutation substrate yielded a Vmax value in the same range as the wild-type, but the KM value was increased by 50 fold. These results suggest the turnover rate of the enzyme-peptide complex is not affected by the mutation on the peptide. However, interpreting KM as a surrogate for affinity, the mutation reduces the affinity of the substrate for the enzyme. Preliminary modelingresults indicate that suboptimal interaction between BACE and the T673 hydroxyl group, which do not offset its increase desolvation, might be one of the reasons affecting the free energy of binding of the mutant. We also confirmed previous observations that in cells overexpressing APP A673T, soluble APP beta (sAPPb) secretion, primary product of BACE1 cleavage, is reduced by 50% compared to cells overexpressing the wild type construct. Conclusions: Taken together, this data suggest that a reduction of BACE affinity for this mutated APP explains how it may protect against Alzheimer’s disease. Thus providing strong evidence that reducing BACE activity by inhibitors may be beneficial for the treatment of AD.
P4-289
NORMAL HEALTHY DONORS POSSESS PLASMA IGG REACTIVE TO A NEUTRALIZING EPITOPE FOR TOXIC AND AMYLOID-SEEDING BETAAMYLOID OLIGOMERS
Ebrima Gibbs1, Judith Silverman1, Claudia Balducci2, Jing Wang3, Hui Chen4, Marni Uger5, Andrea Masi6, Valeriy Ostapchenko7, Marco Prado8, Weihong Song1, Gianluigi Forloni9, Cheryl Wellington10, Laura Saward6, Neil Cashman1, 1University of British Columbia, Vancouver, British Columbia, Canada; 2Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy; 3University of British Coumbia, Vancouver, British Columbia, Canada; 4Amorfix Life Sciences, Mississauga, Ontario, Canada; 5Amorfix Life Sciences Ltd., Mississauga, Ontario, Canada; 6Cangene Corporation, Winnipeg, Manitoba, Canada; 7University of Western Ontario, London, Ontario, Canada; 8University of Western Ontario, London, Ontario, Canada; 9Istituto di Ricerche Farmacologiche, Milano, Italy; 10The University of British Columbia, Vancouver, British Columbia, Canada. Contact e-mail: [email protected] Background: Oligomers of amyloid-b (Ab) peptide are implicated in Alzheimer’s disease (AD) synaptic dysfunction, tau phosphorylation and neurofibrillary tangle deposition, neuronal cell death and regional spread of Ab amyloidosis in the brain. We have identified an immunological epitope unique to Ab oligomers comprising the structurally constrained tripeptide cyclized serine-asparagine-lysine (cSNK).We have reported that the mouse cSNK-specific IgG1 monoclonal antibody 5E3 recognizes synthetic and AD brain-derived Ab oligomers of 45-55 kDa, and blocks neurotoxicity and Ab(1-42) oligomer growth in vitro 1. Methods: The in vivo activity of 5E3 on neurotoxicity/synaptotoxicity was evaluated by novel object recognition (NOR) test performed in C57BL/6 wild-type mice intraventricularly co-injected 2 hours earlier with antibody combined with synthetic Ab(1-42) oligomers 2. P urified IgG from young healthy donors were assayed for cSNK and synthetic Ab(1-42) oligomers using Biacore TM 1 and MagPlex TM5 immunoassays 1,3. Results: Preincubation with the monoclonal 5E3, but not control IgG1, effectively abrogated the acute NOR deficit induced by injection of A b(1-42) oligomers (p<0.01); no NOR deficit was observed on infusion of 5E3 antibody alone. MagPlex TM and Biacore TM immunoassays revealed cSNK IgG in young healthy donors, which were strongly correlated (Pearson test p<0.005). Biacore TM revealed strong correlation of IgG binding to cSNK peptide and A b(1-42) oligomers (Pearson test p<0.001). cSNK IgG was primarily IgG1 subclass, w 500 nM affinity for A b(1-42) oligomers. Conclusions: The data are consistent with the cSNK defining a "neutralizing epitope" for those Ab oligomers triggering neurotoxicity/synaptotoxicity and oligomer propagation. Natural or engineered antibodies against cSNK may have efficacy as an AD passive immunotherapy, and cSNK as a prophylactic vaccine target for populations at
high-risk for AD. 1) Silverman et al. Alz Demen 2012; 8 suppl.04-06-03. 2) Balducci et al. Proc Natl Acad Sci U S A. 2010; 107:2295-300. 3) Toth et al Alz Demen, 2012; 8 suppl.P1-228. P4-290
NOVEL FUSION PROTEIN BIVALENT FOR A GENERAL AMYLOID INTERACTION MOTIF REDUCES BETA-AMYLOID AGGREGATES IN TRANSGENIC MICE
Jonathan Levenson1, Eva Asp1, Maria Becker2, Rajaraman Krishnan1, Eliezer Masliah3, Elliott Mufson4, Muhammad Nadeem5, Sylvia Perez5, Ming Proschitsky1, Edward Rockenstein3, Haim Tsubery6, Kimberley Gannon1, 1NeuroPhage Pharmaceuticals, Cambridge, Massachusetts, United States; 2Tel Aviv University, Tel Aviv, Israel; 3 University of California San Diego, La Jolla, California, United States; 4 Rush University, Chicago, Illinois, United States; 5Rush University Medical Center, Chicago, Illinois, United States; 6Tel Aviv University, Tel Aviv, Israel. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is characterized by both Amyloid b (Ab) plaque deposition and intracellular neurofibrillary tangles accompanied by progressive cognitive decline. We have shown that NPT002 (filamentous bacteriophage M13) dose-dependently clears Ab plaques and restores normal cognitive performance in aged Tg2576 mice. Recently, we isolated the protein motif from NPT002 responsible for the amyloid-interacting activity, which we call the generic amyloid interacting motif or GAIM. The present study was conducted to evaluate whether fusion proteins bivalent for GAIM were able to clear b-amyloid aggregates in transgenic Alzheimer’s mouse models. Methods: In the present study, we administered test article or control treatment via a single intra-hippocampal 2mL injection per hemisphere (7-8mg of protein per injection). Mice used for these studies included 17-19 month old male Tg2576 mice and 17-19 month old male & female 3xTg mice. Animals were sacrificed 7 days post-treatment. Paraformaldehyde-fixed brains were serially sectioned and analyzed for Ab load in the hippocampus and surrounding cortical areas by ThioS fluorescence and anti-amyloid antibody staining (82E1). Neuro-inflammation was monitored by antibody staining for Iba1 and GFAP. Synaptic density was assessed by antibody staining for synaptophysin (SY38). Systemic administration of NPT088 was via intraperitoneal injection at 10mg/kg. Results: Intrahippocampal injection of either NPT014 (human IgG 4 -Fc-GAIM) or NPT088 (human IgG 1 -Fc-GAIM) into aged Tg2576 mice resulted in significantly lower b-amyloid plaque in hippocampus and surrounding neocortex 7 days after treatment as measured by either 82E1 or ThioS. The decrease in b-amyloid was accompanied by significant increases in Iba-1 and synaptophysin. GFAP and Perl’s Prussian Blue staining was unaffected by treatment. Similar to observations in aged Tg2576 mice, intra-hippocampal injection of NPT088 into aged 3xTg mice resulted in significant decreases in b-amyloid in the hippocampus. The timing and magnitude of the effects of NPT088 and NPT014 on b-amyloid were similar to previous studies with NPT002. Moreover, acute systemic administration of NPT088 to wt mice produced brain penetration. Conclusions: NPT088 and NPT014 safely reduced b-amyloid plaque and increased synaptic density within 7 days of direct-to-brain administration in transgenic mouse models. These data support the use of GAIM-containing molecules as a novel therapeutic approach for reducing Ab plaque. P4-291
PREDICTING IN VIVO BACE INHIBITOR EFFICACY: ARE HUMAN IPS-DERIVED NEURONS SUPERIOR?
Christine Oborski1, Sandra Engle2, Charles Nolan3, Yao Zhang1, Leslie Pustilnik2, Stephen Noell2, Ashley Robshaw1, Kevin Atchison1, Cheng Chang1, Yasong Lu1, Kewa Mou1, Michael Brodney1, David Riddell1, 1Pfizer Inc., Cambridge, Massachusetts, United States; 2 Pfizer Inc., Groton, Connecticut, United States; 3Pfizer Inc., Cambridge, Massachusetts, United States. Contact e-mail: christine.e.oborski@pfizer. com Background: BACE is the first enzyme involved in the sequential cleavage of APP leading to b -amyloid (A b) generation. The presence of A b in
Poster Presentations: P4 critical brain regions is considered to be a causative factor in the cognitive decline and neuronal degeneration associated with Alzheimer’s disease (AD). Thus, reducing levels of toxic A b species by inhibiting BACE may be a viable therapeutic strategy for the treatment of AD. Effectively selecting BACE inhibitors for in vivo profiling requires high confidence in the translatability of in vitro potency. Human iPS-derived neurons, which more closely represent human neurons, have been proposed to be a superior cellular model for translating in vitro potency to in vivo (and later clinical) efficacy. Methods: BACE inhibitors representing 3 chemical series were chosen for profiling in a soluble enzyme assay, an APP over-expressing human H4 neuroglioma cell line, a rodent primary neuronal culture, and in human iPS-derived neurons. Our human iPS line was derived from adult non-diseased fibroblasts that were reprogrammed into GABAergic neurons. IC50 correlations for A b lowering were built to compare potency across these assays. Additionally, wild-type 129/SVE mice were dosed with several of these BACE inhibitors to establish the in vivo brain IC50 for A b. For all assays, in vitro -to- in vivo correlations (IVIVCs) of in vitro IC50 values and in vivo IC50 values were generated. Results: We report a high correlation in BACE inhibitor potency between all the in vitro assays examined, including the iPS-derived neurons. Additionally, IVIVCs for the various in vitro assays described translate well to in vivo rodent efficacy. Conclusions: Selecting appropriate chemical matter for in vivo profiling is essential for efficient drug discovery. While the non-diseased human iPS-derived neurons that we tested are more representative of human neurons than the other assay models examined, they do not provide any distinct advantage in translating in vitro potency to in vivo efficacy and thus do not appear to represent a superior translatable cellular model for screening. It remains to be seen if iPSderived neurons from AD patients offer any advantage in screening for Alzheimer’s disease therapeutics.
P4-292
MULTITARGET STRATEGY OF TRADITIONAL CHINESE MEDICINE IN TREATMENT OF ALZHEIMER’S DISEASE
Lin Li1, Lan Zhang1, Ruyi Zhang1, Rong Wang2, 1Xuanwu Hospital of Capital Medical University, Beijing, China; 2Xuanwu Hospital of Capital Medical University, Beijing, China. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is a multifactorial complex disease. The failure of recent development of AD therapeutic agents in clinical trials is partly due to their single-target or single-pathway effect. Methods: We have committed to the research of traditional Chinese medicine in treatment of AD, and have developed two new drugs: Shenwu capsule (SW) composed of 6 kinds of traditional Chinese herbs, and Tetrahydroxystilbene glucoside (TSG) extracted from Polygonum multiflorum. Results: Our studies found that SW and TSG significantly improved learning-memory ability in 7 kinds of AD-like animal models, and their action mechanisms including: (1) increased the ratio of cholinacetyl-transfetase (ChAT)/cholinesterase (AchE); (2) decreased the number of amyloid plaques and the content of Ab, and inhibited the expression of b-secretase or presenilin-1; (3) inhibited a-synuclein mRNA expression, protein expression and aggregation, and activated ubiquitin-proteasome system; (4) increased the expression of protein phosphortase 2A (PP2A), inhibited hyperphosphorylation of tau protein, and protected cytoskeleton; (5) inhibited microglial activation, and decreased the content of proinflammatory cytokine TNF-a and IL-1b; (6) enhanced mitochondrial function, inhibited oxidative stress, and decreased neuron apoptosis; (7) elevated the expression of endogenous neurotrophic factor NGF and BDNF and their receptors, and activated neuron survival signal transduction pathway; (8) increased synaptic plasticity by enhancing the long-term potentiation, elevated the number of synapses, and increased the expression of synaptophysin. Conclusions: The results demonstrated that SW and TSG exerted their therapeutic effects on multitargets and multi-pathways in the complex pathogenesis of AD, especially had both neuroprotective effect and neurotrophic effect, suggesting that these drugs may be beneficial to the early intervention and delaying the progression of AD. Now SW has completed phase III clinical trial for the
P811
treatment of AD and mild cognitive impairment (MCI), and obtained good therapeutic effects; the phase II clinical trial for the treatment of AD is underway.
P4-293
STATIN EXPOSURE AND STRUCTURAL INTEGRITY MEASURES IN THE BRAIN OF OLDER ADULTS IN THE HEALTH ABC STUDY
Neelesh Nadkarni1, Subashan Perera1, Joseph Hanlon1, Stephanie Studenski1, Marshall Elam2, Tamara Harris3, Stephen Kritchevsky4, Kristine Yaffe5, Anne Newman6, Caterina Rosano1, 1 University of Pittsburgh, Pittsburgh, Pennsylvania, United States; 2 University of Tennessee Health Sciences Center, Memphis, Tennessee, United States; 3NIA, Bethesda, Maryland, United States; 4Wake Forest University, Winston-Salem, North Carolina, United States; 5University of California San Francisco, San Francisco, California, United States; 6 University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, United States. Contact e-mail: [email protected] Background: Pleotropic effects of statins are purported to benefit Alzheimer’s disease and cerebrovascular. We hypothesized that these effects could reflect as "superior" measures of brain structural integrity in statin exposed individuals, particularly in those with suboptimal performance on cognitive screening tools. Furthermore, these statin effects would be strongest in subcortical regions that are most susceptible to small-vessel disease. Methods: In 295 participants enrolled in the Health ABC Study,we identified statin exposure from medication-use data and stratified thier cognitive performance by tertiles of the Modified Mini-Mental Status Examination scores (3MS) recorded in 2004-2005. We extractedneuroimaging data from 2007-2008 and quantified integrity of brain white (WM) and gray matter (GM) and tracts of interest (anterior thalamic radiation (ATR), superior longitudinal fasciculi (SLF), corpus callosum (frontal (CCF), occipital (CCO)) using fractional anisotropy (FA), white matter hyperintensities volumes (WMHv), peak-height magnetization transfer ratio (phMTR) and mean diffusivity (MD) where applicable. We fitted two-way AN(C)OVA models to brain measures with statin exposure, 3MS tertiles and interaction; and performed stratified comparisons for statin exposure within 3MS tertiles adjusting for covariates (age, gender, race, education, coronary heart disease, diabetes and stroke). Results: Mean age of the sample was 80.1 years (58% female, 59% Caucasian, 86% with at least high-school education). There were no demographic differences in statin exposed (n¼106) and non-exposed (n¼185) groups. Statin exposure X 3MS interaction, adjusted for covariates, was significant for total WMHv (p¼0.02) and FA for whole WM (p¼0.01) but not for whole brain phMTR (p¼0.7) or MD for whole GM (p¼0.1), therefore justifyingstratified analysis by 3MS tertiles. Statin exposed participants in the lowest tertile of 3MS scores (86.3565.76) had lower total WMHv (p¼0.005) and lower WMHv in ATR (p¼0.044), SLF (p¼0.035), CCO (p¼0.002) and CCF (p¼0.016), and, higher FA in WM (p¼0.004), SLF (p¼0.005) and ATR (p¼0.033). The differences in WMHv in the CCO (p¼0.006) and CCF (p¼0.023), and, FA of WM (p¼0.005), ATR (p¼0.016) and SLF (p¼0.014) remained significant after adjustingforconfounders. There were no significant differences in the other 3MS tertiles (94.6361.16 and 98.3461.14). Conclusions: Statins may be associated with white matter integrity in older adults with suboptimal cognitive performance.
P4-294
GAMMA-SECRETASE AS A TARGET FOR ALZHEIMER’S DISEASE THERAPY: SMALLMOLECULE DEVELOPMENT
Corinne Augelli-Szafran1, Katherine Brogan2, Cuiman Cai1, Jian Chen3, Yongli Gu4, Dennis Selkoe5, Han-Xun Wei3, Michael Wolfe6, Jing Zhang1, 1 Laboratory for Experimental Alzheimer Drugs (LEAD), Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States; 2Laboratory for Experimental Alzheimer Drugs (LEAD),