- Email: [email protected]
O4-04-08 β-Amyloid reductions in brain, plasma and CSF of a transgenic mouse model of Alzheimer's disease with a γ-secretase inhibitor
$82
Oral Session 04-05: Therapeutics 2
is largely unresolved. Objectives: Here, we report on the phenotype of knockout mice lacking all three APP family members that we have generated to define the in vivo functions. Results: APP is a member of a larger gene family that includes the amyloid precursor-like proteins, termed APLP1 and APLP2. We previously documented that APLP2 - / APLP1 - / - - and APLP2 - / - A P P - / - - m i c e die postnatally, while APLP1 - / A P P - / - - m i c e and single mutants were viable. To unravel the full range of physiological functions exerted by this highly redundant gene family, we felt it necessary to generate mice lacking all three APP-family members and thus eliminate any residual functional complementation. We now report that triple knockout mice survive through embryonic development, and die shortly after birth. In contrast to double mutant animals with perinatal lethality, we observed a high incidence of cortical dysplasias in triple mutant mice. Cortical dysplasias were characterized by focal ectopic neuroblasts that had migrated through the basal lamina and pial membrane, a phenotype that resembles human type II lissencephaly. Moreover, triple mutants showed a reduction in cortical Cajal Retzius (CR) cell number. Conclusions: Our data suggest that APP/APLPs play a crucial role in the survival of CR cells and neuronal adhesion. Collectively, our data reveal an essential role for APP-family members in normal brain development and early postnatal survival.
I]-AMYLOID REDUCTIONS IN BRAIN, PLASMA IO4-04-08] AND CSF OF A TRANSGENIC MOUSE MODEL OF ALZHEIMER'S DISEASE WITH A y-SECRETASE INHIBITOR Donna M. Batten .1 , Valerie L. Guss I , Jason A. Corsa 1, Alice T. Loo 1,2, Steven B. Hansel 1, Ming Zheng 1, Ben Munoz 3,4, Kumar Srinlvasan 3'5 , Barbara Robertson 1, Joseph R Hendrick 1,6, Jeffery J. Anderson 3,7, Todd A. Verdoorn 1,8, Susan B. Roberts 1, Kevin M. Felsenstein 1,9, David W. Smith 1. 1Bristol-Myers Squibb, Wallingford, CT, USA; 2currently
Vertex Pharmaceutical, Cambridge, MA, USA; 3SIBIA Neurosciences, La Jolla, CA, USA; 4currently Merck Research Laboratories, San Diego, CA, USA; 5currently Neurogenetics, La Jolla, CA, USA; 6currently Intra-Cellular Therapies Inc., New York, NY,, USA; 7currently Cypress Bioscience, Inc., San Diego, CA, USA; 8currently Algos Therapeutics, Inc., St. Paul, MN, USA; 9currently Johnson and Johnson PDR, Spring Hill, PA, USA. Contact e-mail: [email protected]
Background: ~-amyloid peptide (AI3) is believed to play a major role in the etiology of Alzheimer's disease (AD). Inhibition of y-secretase reduces the levels of A~ and may be useful for the treatment of AD. Objective(s): To determine the efficacy of a y-secretase inhibitor in different biological compartments of animals with and without plaques. Also, to look for any potential toxicity in these animals that may be related to inhibition of Notch cleavage. Methods: Tg2576, APP-Swedish transgenic mice were used for these studies, at young ages without plaques, and then at older ages after plaques had developed. BMS-299897 was chosen as a y-secretase inhibitor with suitable pharmacokinetic properties and selectivity for amyloid precursor protein (APP) vs Notch as a substrate. Results: In young mice, BMS-299897 reduced AI3 in brain, plasma and CSF in a dose and time dependant manner. Brain and CSF AI3 reductions were highly correlated in these young transgenic mice in the absence of plaques. When older mice with plaques were given a single dose of BMS-299897, AI3 levels in CSF were reduced, while brain (plaque) A[3 was unchanged. After 2 weeks of treatment, there were also no reductions in brain A[~ in aged mice, although CSF A~ continued to be reduced. To look for potential deleterious effects on Notch processing, CD8+ thymocytes were also examined in young transgenic mice treated for two weeks with BMS-299897. No changes in CD8+ thymocytes were observed. Conclusions: The present studies demonstrated reductions in brain A~ in young, but not plaque beating animals, while both CSF and plasma A~ was reduced in both young and old transgenic mice. CSF AI3 may be a good biomarker for ¥-secretase activity in the central nervous system in AD patients.
Oral Session 0 4 - 0 5 : Therapeutics 2
O4-05-01 [ ENHANCEMENT OF LEARNING AND MEMORY BY STATINS BEYOND ALZHEIMER'S DISEASE Ling Li* 1, Dongfeng C a t 1, Hongquan Wan l, Jiangno Chen 1, Ken-ichiro Fuknchi 1, Helen Kim 1, Robin Lester 1, Robert Lalonde 2. 1 Univ
of Alabama at Birmingham, Birmingham, AL, USA; 2 Univ of Rouen, Rouen, France. Contact e-mail: [email protected]
Background: Decline of learning and memory often associates with aging. Severe memory and cognitive impairment leads to dementia such as Alzheimer's disease (AD). To date, there is no satisfactory prevention or treatment for dementia or normal age-associated memory loss. Statins are a class of cholesterol-lowering drugs that have been widely used for controlling plasma cholesterol levels and have effectively decreased the risk of cardiovascular disease. Recently, retrospective studies have shown that statin use is associated with a reduced risk of dementia. The results from recent prospective studies with statins, however, are not conclusive. The mechanisms by which statins protect against dementia are not known. In the case of Alzheimer's disease, statins modulate processing of [3-amyloid precursor protein (APP) and decrease the production of 13-amyloid as shown by in vitro and in vivo studies, which may partially account for their protective effect against Alzheimer's disease. While much attention has been focused on the potential use of statins in dementia, there have been few studies of the effect of statins on cognitive functions in normal aging. Objective(s): The objective of this study is to investigate the effect of a statin treatment on learning and memory in both AD-model and normal mice. Methods: Transgenic (Tg2576) mice overexpressing a mutant form of human APP are widely used as a mouse model of AD. We treated a group of Tg2576 mice and their non-transgenic littermates with simvastatin (provided by Merck), a widely used statin drug, and assessed behavioral changes associated with the statin treatment. Results: We found that simvastatin treatment corrected learning and memory deficits in Tg2576 mice, and more intriguingly, it significantly enhanced learning and memory in normal non-transgenic mice, suggesting possible mechanisms that are independent of lS-amyloid/APP metabolism. In preliminary studies in our laboratory, simvastatin treatment was associated with a more robust induction of hippocampal long-term potentiation and a higher expression of several signaling molecules in the cerebrum of treated mice. Conclusions: Our studies demonstrated beneficial effects of statins on learning and memory in normal aging as well as in Alzheimer-type dementia. I
04-05-02 I PLEIOTROPIC EFFECTS OF STATINS ON GENE I
EXPRESSION IN CEREBRAL CORTEX OF MICE Leslie N. Johnson-Anuna* 1, Gunter P. Eckert 2, Urule Igbavboa 1, Jan H. Keller 2, Walter E. Muller 2 , W. Gibson Wood 1.1 University of
Minnesota/VA Medical Center, Minneapolis, MN, USA; 2University of Frankfurt, Frankfurt, Germany. Contact e-mail: [email protected]
Background: Several different lines of evidence point to a potentially important but not well understood association between Alzheimer's disease (AD) and cholesterol. A most interesting finding of this association between cholesterol and AD is that inhibitors of 3-hydroxy-3-methylghitaryl eoenzyme A (HMG-CoA) reductase (statins) lower the risk of developing AD. However, it is unclear as to whether the apparent efficacy of statins is related to changes in brain cholesterol levels. Statins not only inhibit HMG-CoA reductase but those drugs have effects that are independent of effects on cholesterol homeostasis. Objective(s): The overall objective of this study was to elucidate the gene expression patterns in cerebral cortex of mice administered the two hydrophnhic statins, lovastatin and simvastatin and the hydrophilic statin, pravastatin. Statins levels were determined in brain. Methods: Mice were administered statins by oral gavage once a day for 21 days. Gene expression was profiled by microarray using Affymetrix murine U74A chips. Selected gene expression changes displaying a 1.8-fold difference or greater as compared to control values were verified by RT-PCR. Brain statin levels were determined using LC-MS. Results: The total number
Oral Session 04-05: Therapeutics 2
is largely unresolved. Objectives: Here, we report on the phenotype of knockout mice lacking all three APP family members that we have generated to define the in vivo functions. Results: APP is a member of a larger gene family that includes the amyloid precursor-like proteins, termed APLP1 and APLP2. We previously documented that APLP2 - / APLP1 - / - - and APLP2 - / - A P P - / - - m i c e die postnatally, while APLP1 - / A P P - / - - m i c e and single mutants were viable. To unravel the full range of physiological functions exerted by this highly redundant gene family, we felt it necessary to generate mice lacking all three APP-family members and thus eliminate any residual functional complementation. We now report that triple knockout mice survive through embryonic development, and die shortly after birth. In contrast to double mutant animals with perinatal lethality, we observed a high incidence of cortical dysplasias in triple mutant mice. Cortical dysplasias were characterized by focal ectopic neuroblasts that had migrated through the basal lamina and pial membrane, a phenotype that resembles human type II lissencephaly. Moreover, triple mutants showed a reduction in cortical Cajal Retzius (CR) cell number. Conclusions: Our data suggest that APP/APLPs play a crucial role in the survival of CR cells and neuronal adhesion. Collectively, our data reveal an essential role for APP-family members in normal brain development and early postnatal survival.
I]-AMYLOID REDUCTIONS IN BRAIN, PLASMA IO4-04-08] AND CSF OF A TRANSGENIC MOUSE MODEL OF ALZHEIMER'S DISEASE WITH A y-SECRETASE INHIBITOR Donna M. Batten .1 , Valerie L. Guss I , Jason A. Corsa 1, Alice T. Loo 1,2, Steven B. Hansel 1, Ming Zheng 1, Ben Munoz 3,4, Kumar Srinlvasan 3'5 , Barbara Robertson 1, Joseph R Hendrick 1,6, Jeffery J. Anderson 3,7, Todd A. Verdoorn 1,8, Susan B. Roberts 1, Kevin M. Felsenstein 1,9, David W. Smith 1. 1Bristol-Myers Squibb, Wallingford, CT, USA; 2currently
Vertex Pharmaceutical, Cambridge, MA, USA; 3SIBIA Neurosciences, La Jolla, CA, USA; 4currently Merck Research Laboratories, San Diego, CA, USA; 5currently Neurogenetics, La Jolla, CA, USA; 6currently Intra-Cellular Therapies Inc., New York, NY,, USA; 7currently Cypress Bioscience, Inc., San Diego, CA, USA; 8currently Algos Therapeutics, Inc., St. Paul, MN, USA; 9currently Johnson and Johnson PDR, Spring Hill, PA, USA. Contact e-mail: [email protected]
Background: ~-amyloid peptide (AI3) is believed to play a major role in the etiology of Alzheimer's disease (AD). Inhibition of y-secretase reduces the levels of A~ and may be useful for the treatment of AD. Objective(s): To determine the efficacy of a y-secretase inhibitor in different biological compartments of animals with and without plaques. Also, to look for any potential toxicity in these animals that may be related to inhibition of Notch cleavage. Methods: Tg2576, APP-Swedish transgenic mice were used for these studies, at young ages without plaques, and then at older ages after plaques had developed. BMS-299897 was chosen as a y-secretase inhibitor with suitable pharmacokinetic properties and selectivity for amyloid precursor protein (APP) vs Notch as a substrate. Results: In young mice, BMS-299897 reduced AI3 in brain, plasma and CSF in a dose and time dependant manner. Brain and CSF AI3 reductions were highly correlated in these young transgenic mice in the absence of plaques. When older mice with plaques were given a single dose of BMS-299897, AI3 levels in CSF were reduced, while brain (plaque) A[3 was unchanged. After 2 weeks of treatment, there were also no reductions in brain A[~ in aged mice, although CSF A~ continued to be reduced. To look for potential deleterious effects on Notch processing, CD8+ thymocytes were also examined in young transgenic mice treated for two weeks with BMS-299897. No changes in CD8+ thymocytes were observed. Conclusions: The present studies demonstrated reductions in brain A~ in young, but not plaque beating animals, while both CSF and plasma A~ was reduced in both young and old transgenic mice. CSF AI3 may be a good biomarker for ¥-secretase activity in the central nervous system in AD patients.
Oral Session 0 4 - 0 5 : Therapeutics 2
O4-05-01 [ ENHANCEMENT OF LEARNING AND MEMORY BY STATINS BEYOND ALZHEIMER'S DISEASE Ling Li* 1, Dongfeng C a t 1, Hongquan Wan l, Jiangno Chen 1, Ken-ichiro Fuknchi 1, Helen Kim 1, Robin Lester 1, Robert Lalonde 2. 1 Univ
of Alabama at Birmingham, Birmingham, AL, USA; 2 Univ of Rouen, Rouen, France. Contact e-mail: [email protected]
Background: Decline of learning and memory often associates with aging. Severe memory and cognitive impairment leads to dementia such as Alzheimer's disease (AD). To date, there is no satisfactory prevention or treatment for dementia or normal age-associated memory loss. Statins are a class of cholesterol-lowering drugs that have been widely used for controlling plasma cholesterol levels and have effectively decreased the risk of cardiovascular disease. Recently, retrospective studies have shown that statin use is associated with a reduced risk of dementia. The results from recent prospective studies with statins, however, are not conclusive. The mechanisms by which statins protect against dementia are not known. In the case of Alzheimer's disease, statins modulate processing of [3-amyloid precursor protein (APP) and decrease the production of 13-amyloid as shown by in vitro and in vivo studies, which may partially account for their protective effect against Alzheimer's disease. While much attention has been focused on the potential use of statins in dementia, there have been few studies of the effect of statins on cognitive functions in normal aging. Objective(s): The objective of this study is to investigate the effect of a statin treatment on learning and memory in both AD-model and normal mice. Methods: Transgenic (Tg2576) mice overexpressing a mutant form of human APP are widely used as a mouse model of AD. We treated a group of Tg2576 mice and their non-transgenic littermates with simvastatin (provided by Merck), a widely used statin drug, and assessed behavioral changes associated with the statin treatment. Results: We found that simvastatin treatment corrected learning and memory deficits in Tg2576 mice, and more intriguingly, it significantly enhanced learning and memory in normal non-transgenic mice, suggesting possible mechanisms that are independent of lS-amyloid/APP metabolism. In preliminary studies in our laboratory, simvastatin treatment was associated with a more robust induction of hippocampal long-term potentiation and a higher expression of several signaling molecules in the cerebrum of treated mice. Conclusions: Our studies demonstrated beneficial effects of statins on learning and memory in normal aging as well as in Alzheimer-type dementia. I
04-05-02 I PLEIOTROPIC EFFECTS OF STATINS ON GENE I
EXPRESSION IN CEREBRAL CORTEX OF MICE Leslie N. Johnson-Anuna* 1, Gunter P. Eckert 2, Urule Igbavboa 1, Jan H. Keller 2, Walter E. Muller 2 , W. Gibson Wood 1.1 University of
Minnesota/VA Medical Center, Minneapolis, MN, USA; 2University of Frankfurt, Frankfurt, Germany. Contact e-mail: [email protected]
Background: Several different lines of evidence point to a potentially important but not well understood association between Alzheimer's disease (AD) and cholesterol. A most interesting finding of this association between cholesterol and AD is that inhibitors of 3-hydroxy-3-methylghitaryl eoenzyme A (HMG-CoA) reductase (statins) lower the risk of developing AD. However, it is unclear as to whether the apparent efficacy of statins is related to changes in brain cholesterol levels. Statins not only inhibit HMG-CoA reductase but those drugs have effects that are independent of effects on cholesterol homeostasis. Objective(s): The overall objective of this study was to elucidate the gene expression patterns in cerebral cortex of mice administered the two hydrophnhic statins, lovastatin and simvastatin and the hydrophilic statin, pravastatin. Statins levels were determined in brain. Methods: Mice were administered statins by oral gavage once a day for 21 days. Gene expression was profiled by microarray using Affymetrix murine U74A chips. Selected gene expression changes displaying a 1.8-fold difference or greater as compared to control values were verified by RT-PCR. Brain statin levels were determined using LC-MS. Results: The total number