Transgenic non-human mammals with progressive neurologic disease

Abstract

Provided is a transgenic non-human eukaryotic animal whose germ cells and somatic cells contain the amyloid precursor protein sequence introduced into the animal, or an ancestor of the animal, at an embryonic stage. In mice, an age-related CNS disorder characterized by agitation, neophobia, seizures, inactivity, diminished cerebral glucose utilization, cortico-limbic gliosis, and death, develops. An acceleration of this disorder occurs in transgenic mice expressing human and mouse Alzheimer amyloid precursor proteins (APP) produced using a hamster prion protein gene-derived cosmid vector that confers position-independent, copy number-dependent expression. In transgenic mice the disorder develops in direct relationship to brain levels of transgenic APP, but mutant APP confers the phenotype at lower levels of expression than wild-type APP. The disorder occurs in the absence of extracellular amyloid deposition, indicating that some pathogenic activities of APP are dissociated from amyloid formation.

What is claimed is:  
     
         1 . A transgenic non-human mammal, said mammal comprising: 
 an amount of amyloid precursor protein expression in neurologic tissues of said mammal sufficient to produce impaired performance of said mammal in memory and learning tests and to induce abnormal neuropathology in a cortico-limbic region of said mammal's brain, wherein said impaired performance and said abnormal neuropathology are as compared to control mammals.    
     
     
         2 . The transgenic non-human mammal according to  claim 1 , wherein said amyloid precursor protein expression is at least about two-fold that of endogenous amyloid precursor protein in a control mammal.  
     
     
         3 . The transgenic non-human mammal according to  claim 1 , wherein said abnormal neuropathology is thioflavin S positive amyloid plaques.  
     
     
         4 . The transgenic non-human mammal according to  claim 1 , wherein said amyloid precursor protein is encoded by a coding sequence derived from a mutant amyloid precursor protein gene.  
     
     
         5 . The transgenic non-human mammal according to  claim 4 , wherein said mutant amyloid precursor protein gene is other than a codon 717 mutant.  
     
     
         6 . The transgenic non-human mammal according to  claim 4 , wherein said coding sequence is substantially free of splice sites.  
     
     
         7 . The transgenic non-human mammal according to  claim 4 , wherein said coding sequence is substantially free of a Kunitz-protease inhibitor domain.  
     
     
         8 . The transgenic non-human mammal according to  claim 1 , wherein said mammal is a rodent.  
     
     
         9 . The transgenic non-human mammal according to  claim 8 , wherein said rodent is a mouse.  
     
     
         10 . The transgenic non-human mammal according to  claim 9 , wherein a nontransgenic ancestor of said mouse is from a strain having greater longevity as compared with other strains of mice.  
     
     
         11 . The transgenic non-human mammal according to  claim 1 , wherein said expression is obtained using regulatory sequences derived from a prion protein gene operatively linked to a coding sequence encoding said amyloid precursor protein.  
     
     
         12 . Progeny of said transgenic non-human mammal according to  claim 1 .  
     
     
         13 . A method for screening for an agent which ameliorates symptoms of Alzheimer's disease, said method comprising: 
 comparing performance on memory and learning tests of a first transgenic non-human mammal contacted with said agent and a second transgenic non-human mammal not contacted with said agent, wherein said first and said second non-human transgenic mammals express amyloid precursor protein in neurologic tissues in an amount sufficient to impair performance on said memory and learning tests as compared to control mammals, whereby an agent which ameliorates said symptoms is identified by superior performance of said first transgenic non-human mammal as compared to said second transgenic non-human mammal on said memory and learning tests.    
     
     
         14 . A method for screening for an agent useful for treating Alzheimer's disease, said method comprising: 
 comparing performance on memory and learning tests of a first transgenic non-human mammal contacted with said agent and a second transgenic non-human mammal not contacted with said agent, wherein said first and said second non-human transgenic mammals express amyloid precursor protein in neurologic tissues in an amount sufficient to impair performance on said memory and learning tests as compared to control mammals; and    comparing neuropathology in a cortico-limbic region of the brain of said first and said second transgenic non-human mammals when said first transgenic non-human mammal exhibits superior performance on said memory and learning tests as compared to said second transgenic non-human mammal, whereby an agent which is useful for treating Alzheimer's disease is identified by a decrease in neuropathologic findings in said first transgenic non-human mammal as compared to said second transgenic non-human mammal.    
     
     
         15 . The method according to  claim 14 , wherein said decreased neuropathologic findings are one or more findings selected from the group consisting of: 
 a reduction in number of thioflavin S-positive Aβ deposits;    a reduction in amount of thioflavin S-positive Aβ deposits a reduction of hypertrophic gliosis in cortico-limbic structures of said brain;    a reduction of diminution of 2-deoxyglucose uptake in cortico-limbic structures of said brain;    a reduction of diminution of 2-deoxyglucose utilization in cortico-limbic structures of said brain.    
     
     
         16 . A method for screening for an agent useful for treating Alzheimer's disease, said method comprising: 
 comparing performance on memory and learning tests of a first transgenic non-human mammal contacted with said agent and a second transgenic non-human mammal not contacted with said agent, wherein said first and said second non-human transgenic mammals express amyloid precursor protein in neurologic tissues in an amount sufficient to impair performance on said memory and learning tests as compared to control mammals; and    comparing age of death of said first and said second transgenic non-human mammals when said first transgenic non-human mammal exhibits superior performance on said memory and learning tests as compared to said second transgenic non-human mammal, whereby an agent which is useful for treating Alzheimer's disease is identified by a greater age at death of said first transgenic non-human mammal as compared to said second transgenic non-human mammal.    
     
     
         17 . A method for screening for an agent which ameliorates symptoms of Alzheimer's disease, said method comprising: 
 comparing exploratory behavior or locomotor behavior of a first transgenic mouse contacted with said agent and a second transgenic mouse not contacted with said agent, wherein said first and said second transgenic mice express amyloid precursor protein in neurologic tissues in an amount sufficient to produce impaired performance on said exploratory and locomotor behavior as compared to control mice, whereby an agent which ameliorates said symptoms is identified by less impaired exploratory or locomotor behavior in said first transgenic mouse as compared to said second transgenic mouse.    
     
     
         18 . The method according to  claim 17 , wherein said exploratory or locomotor behavior is assessed using a corner index test.  
     
     
         19 . The method according to  claim 17 , wherein a nontransgenic ancestor of said mouse is from a strain selected from the group consisting of FVB, Swiss Webster, and C57B6.  
     
     
         20 . The method according to  claim 17 , wherein said amyloid precursor protein is encoded by a coding sequence derived from a K670N-M671L amyloid precursor protein gene.