- Email: [email protected]
Neurofibrillary tangles, neuronal loss, and severe motor changes develop in transgenic mice expressing tau (4R0N) with the frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17) mutation P301L
s59 CLINICAL CHARACTERISTICS IN A FAMILY WITH EARLYONSET ALZHEIMER DISEASE CAUSED BY A MUTATION (V717L) IN THE APP GENE
DITYROSINE CROSS-LINKING PROMOTES STABLE a-SYNUCLEIN POLYMERS Bewit I Ginsson. Hmp
Philadelphia phiu.
Ohjectwz To characterire the clinical phenotype of a family with very early onset AlLheimer disease (AD) caused by a single base pair substitution in the amyloid precursor protein (APP) gene atcodon 717. Background Several families have been dehcrihed with early-onset AD who have causative mutations in the APf gene. Mutation? in wme areas of the gene seem particularly likely to cause early-onset AD. Three different families with different base pair substitutionr at codon 717 causing different amino acid changes have been dewrihed previously. It ia of interest that these different substitutions are associated with some variation in clinical phenotype. Here we characteria a fourth family wth a new haae pair aubatitution and with very early onset AD. Methods All mdivtduals in the proband’s generatmn were examined wtth a history, physical and nrurologlcal examination, magnetic rewnance imaging IMRI), blood tests, lumbar puncture, and neuropaychological testmg. Informawn on 3 prior generations was obtained from wrviving family members. Results The proband, the eldest of 6 sthlings. developed problemr with memory and planning around age 38 and was diagnosed with AD at age 39. The family history included memory problems in her father before his death at age 41 of an Ml, of “shell shock” and memory problems in her paternal grandfather in his late 30’s, and of memory problems m her great-grandmother in her 40’s. The prohand was found to have a base pair mutation at codon 717. causing a valine to leucine amino acid substitution. Her 5 siblings were counseled and examined; one brother (age 37) who had noticed memory problems for 2 years was found to have prodromal dementia; the others were normal. MRI scans revealed mild cerebral atrophy in the prohand and slightly enlarged ventricles in an unaffected sibling. Bloodwork wab normal in all 6 and CSF showed levels of muand a-P protein consistent with AD m the 2 affected person\. Four of the Ghlings underwent genetic te\ting: 2 of the\e, including the brother wtth prodromal AD, were found to have the mutation. Conclusion They is a newly dewrihed family with an APP nutatimatcodon 717 with an earlier age of onset than in prrviou~ly dew-ihed 717 familie<.
Oral Presentation:
Animal Models (Cytoskeletal)
TAU SPLICING CAUSED 12671ABERRANT ATED WITH INHERITED DEMENTIA
BY MUTATIONS
ASSOCI-
Frontotemporal dementta accounts for a significant fractmn of dementia case\. Frontotempotal dementia with parkinsomw~ linked to chromosome 17 (RDP-17) IS associated with either exonic or intronic mutations in the tau gene. Accumulatmg evidence supports the involvement of aberrant pre-mRNA splicing in the pathogeneaia of neurodegenerative disorders. Little is known about molecular mechanwns of the sphcing defects underlying these diseases. To establish a model system for studying the role of pre-mRNA splicing in neurodegenerative diseases. we have constructed a tau mini-gene that reproduces tau alternative splicing in both cultured cells and in vitro biochemical ways. We demonstrate that mutationr m a nonconserved intronic region of the human tau gene lead to increased splicing between exon IOand exon I I. Systematic biochemical analyses indicate the importance of U I snRNP and, to a lesw extent. U6 ?nRNP, m differentially recognizing wild-typr versw intronic mutant tau pre-mRNA$. Gel mobility shift using purified UI snRNP and oligonucleotide-directed RNase H cleavage experiments support that the intronic mutations destabilize a stem-loop structure that sequesters the 5’ splice site downstream of exon IO in tau pre-mRNA. leading to an mcreaae in Ul snRNP binding and in splicing between exon IO and exon I I, Thus, mutations in non-conserved intronic regions that increase, rather than decrease alternative splicing can be an important pathogenic mechanism for the development of human diseases. Potential mechanisms of aberrant splicing in human pathogenesis and implication of correcting splicing defects in disease treatment will be discussed. LEARNING OBJECTIVES I. Investigate the role of alternative splicing in pathogen&s of neurodegeneratwe disorders. 2. Understand molecular mechanism of aberrant splung in dementia. 3. Study the regulation of human tw gene expression.
PA:
PA; Virguzirr
of Pmnsylvaniu,
Univ
of Phdudelphia,
Philadelphia,
Hurry M
Ischiropoulos,
Philudelphin. PA:
Qiping Children’s
OF
PA: Josr M Sousa, Childrm
Chm,
-Y Lee. Univ of Prnr~.~~lvunra.
FORMATION
Acad
Hasp
Hasp
of Philndelphro,
Philodrlphin.
‘>
of Philodelphrrr, Philndel-
PA
Intracellular proteinaceous aggregates are hallmarks of many common neurodegenerative disorders, and recent studies have shown that a-synuclrin is a major component of several pathological intracellular inclusions including Lcwy bodies (LBs) in Parkinson’s disease (PD) and glial cytoplasmic inclusions (Ccl\) in multiple system atrophy. However, the molecular mechanisms underlying u-synuclein aggregation into tilamentous inclusions remains unknown. Since oxidative stress is a potential pathogenic mediator of PD and other neurodegenerative direasrs. we asked if rrxidative and/or nitrative events alter a-~ynuclem and induce aggregation. We rhow that exposure of human recombinant rr-synuclein to nitrating agents (peroxynitrite/C02 or myeloperoxidaae/H202/nitrite) induces formation of nitrated n-synuclein oligomers that are highly stahihxd due to covalent crowlinking via the oxidation of tyrosine to form a,“‘-dityrosine. We also demonstrate that oxidation and mtration of pre-assembled a-synuclein filaments stabilizes these filaments to withstand denaturing conditions and enhanceb formation of SDS-insoluble, heat-stable high molecular weight aggregates. Thus. these data wggest that oxidative and nmativc modifications are involved m mechanisms underlying the pathogen&\ of LBs and GCla as well as u-synuclein pathologies in other rynuclanopathie\.
NEUROFIBRILLARY TANGLES, NEURONAL LOSS, AND SEVERE MOTOR CHANGES DEVELOP IN TRANSGENIC MICE EXPRESSING TAU (4RON) WITH THE FRONTOTEMPORAL DEMENTIA WITH PARKINSONISM LINKED TO CHROMOSOME 17 (FTDP-17) MUTATION P3OIL
Mutation\ in the microtubule associated protem tin1 cawe frontotemporal dementia and parkmwnism linked to chromosome I7 (FTDP-17). Expression of human tau containing an FTDP-17 mutatton (P3OlL) in tranagenic mice resulted in severe motor and behavioral deficits and the age and dose dependent development of neurofibrillary tangles. neuronal log, and gliosis similar to that seen in human tauopathw Motor dysfunctwn and behavioral changes were ewdent rangmg from 6.5.9M in hemuygoter and SM-6M in homorygote\. Neurofihrlllary tangle\ were evident in the pontinc base, dentate nucleus. locus ceruleus. amygdala, wb\tantia nigra. and spinal cord with pre-tangle formattons in the hippocampal wucture and the cortex. Tau powve \phemids, reactive glioais, and neuronal loss occurred in the porn and the spinal colds of tran\gemc P3OlL ammal\. The phenotype of ammals expressmg P3OlL mutant tau contam the key feature\ ot FTDP-I7 and related tauopathies, making them excellent models for the wdy of neurodegeneratlon and lilu deposItion.
DITYROSINE CROSS-LINKING PROMOTES STABLE a-SYNUCLEIN POLYMERS Bewit I Ginsson. Hmp
Philadelphia phiu.
Ohjectwz To characterire the clinical phenotype of a family with very early onset AlLheimer disease (AD) caused by a single base pair substitution in the amyloid precursor protein (APP) gene atcodon 717. Background Several families have been dehcrihed with early-onset AD who have causative mutations in the APf gene. Mutation? in wme areas of the gene seem particularly likely to cause early-onset AD. Three different families with different base pair substitutionr at codon 717 causing different amino acid changes have been dewrihed previously. It ia of interest that these different substitutions are associated with some variation in clinical phenotype. Here we characteria a fourth family wth a new haae pair aubatitution and with very early onset AD. Methods All mdivtduals in the proband’s generatmn were examined wtth a history, physical and nrurologlcal examination, magnetic rewnance imaging IMRI), blood tests, lumbar puncture, and neuropaychological testmg. Informawn on 3 prior generations was obtained from wrviving family members. Results The proband, the eldest of 6 sthlings. developed problemr with memory and planning around age 38 and was diagnosed with AD at age 39. The family history included memory problems in her father before his death at age 41 of an Ml, of “shell shock” and memory problems in her paternal grandfather in his late 30’s, and of memory problems m her great-grandmother in her 40’s. The prohand was found to have a base pair mutation at codon 717. causing a valine to leucine amino acid substitution. Her 5 siblings were counseled and examined; one brother (age 37) who had noticed memory problems for 2 years was found to have prodromal dementia; the others were normal. MRI scans revealed mild cerebral atrophy in the prohand and slightly enlarged ventricles in an unaffected sibling. Bloodwork wab normal in all 6 and CSF showed levels of muand a-P protein consistent with AD m the 2 affected person\. Four of the Ghlings underwent genetic te\ting: 2 of the\e, including the brother wtth prodromal AD, were found to have the mutation. Conclusion They is a newly dewrihed family with an APP nutatimatcodon 717 with an earlier age of onset than in prrviou~ly dew-ihed 717 familie<.
Oral Presentation:
Animal Models (Cytoskeletal)
TAU SPLICING CAUSED 12671ABERRANT ATED WITH INHERITED DEMENTIA
BY MUTATIONS
ASSOCI-
Frontotemporal dementta accounts for a significant fractmn of dementia case\. Frontotempotal dementia with parkinsomw~ linked to chromosome 17 (RDP-17) IS associated with either exonic or intronic mutations in the tau gene. Accumulatmg evidence supports the involvement of aberrant pre-mRNA splicing in the pathogeneaia of neurodegenerative disorders. Little is known about molecular mechanwns of the sphcing defects underlying these diseases. To establish a model system for studying the role of pre-mRNA splicing in neurodegenerative diseases. we have constructed a tau mini-gene that reproduces tau alternative splicing in both cultured cells and in vitro biochemical ways. We demonstrate that mutationr m a nonconserved intronic region of the human tau gene lead to increased splicing between exon IOand exon I I. Systematic biochemical analyses indicate the importance of U I snRNP and, to a lesw extent. U6 ?nRNP, m differentially recognizing wild-typr versw intronic mutant tau pre-mRNA$. Gel mobility shift using purified UI snRNP and oligonucleotide-directed RNase H cleavage experiments support that the intronic mutations destabilize a stem-loop structure that sequesters the 5’ splice site downstream of exon IO in tau pre-mRNA. leading to an mcreaae in Ul snRNP binding and in splicing between exon IO and exon I I, Thus, mutations in non-conserved intronic regions that increase, rather than decrease alternative splicing can be an important pathogenic mechanism for the development of human diseases. Potential mechanisms of aberrant splicing in human pathogenesis and implication of correcting splicing defects in disease treatment will be discussed. LEARNING OBJECTIVES I. Investigate the role of alternative splicing in pathogen&s of neurodegeneratwe disorders. 2. Understand molecular mechanism of aberrant splung in dementia. 3. Study the regulation of human tw gene expression.
PA:
PA; Virguzirr
of Pmnsylvaniu,
Univ
of Phdudelphia,
Philadelphia,
Hurry M
Ischiropoulos,
Philudelphin. PA:
Qiping Children’s
OF
PA: Josr M Sousa, Childrm
Chm,
-Y Lee. Univ of Prnr~.~~lvunra.
FORMATION
Acad
Hasp
Hasp
of Philndelphro,
Philodrlphin.
‘>
of Philodelphrrr, Philndel-
PA
Intracellular proteinaceous aggregates are hallmarks of many common neurodegenerative disorders, and recent studies have shown that a-synuclrin is a major component of several pathological intracellular inclusions including Lcwy bodies (LBs) in Parkinson’s disease (PD) and glial cytoplasmic inclusions (Ccl\) in multiple system atrophy. However, the molecular mechanisms underlying u-synuclein aggregation into tilamentous inclusions remains unknown. Since oxidative stress is a potential pathogenic mediator of PD and other neurodegenerative direasrs. we asked if rrxidative and/or nitrative events alter a-~ynuclem and induce aggregation. We rhow that exposure of human recombinant rr-synuclein to nitrating agents (peroxynitrite/C02 or myeloperoxidaae/H202/nitrite) induces formation of nitrated n-synuclein oligomers that are highly stahihxd due to covalent crowlinking via the oxidation of tyrosine to form a,“‘-dityrosine. We also demonstrate that oxidation and mtration of pre-assembled a-synuclein filaments stabilizes these filaments to withstand denaturing conditions and enhanceb formation of SDS-insoluble, heat-stable high molecular weight aggregates. Thus. these data wggest that oxidative and nmativc modifications are involved m mechanisms underlying the pathogen&\ of LBs and GCla as well as u-synuclein pathologies in other rynuclanopathie\.
NEUROFIBRILLARY TANGLES, NEURONAL LOSS, AND SEVERE MOTOR CHANGES DEVELOP IN TRANSGENIC MICE EXPRESSING TAU (4RON) WITH THE FRONTOTEMPORAL DEMENTIA WITH PARKINSONISM LINKED TO CHROMOSOME 17 (FTDP-17) MUTATION P3OIL
Mutation\ in the microtubule associated protem tin1 cawe frontotemporal dementia and parkmwnism linked to chromosome I7 (FTDP-17). Expression of human tau containing an FTDP-17 mutatton (P3OlL) in tranagenic mice resulted in severe motor and behavioral deficits and the age and dose dependent development of neurofibrillary tangles. neuronal log, and gliosis similar to that seen in human tauopathw Motor dysfunctwn and behavioral changes were ewdent rangmg from 6.5.9M in hemuygoter and SM-6M in homorygote\. Neurofihrlllary tangle\ were evident in the pontinc base, dentate nucleus. locus ceruleus. amygdala, wb\tantia nigra. and spinal cord with pre-tangle formattons in the hippocampal wucture and the cortex. Tau powve \phemids, reactive glioais, and neuronal loss occurred in the porn and the spinal colds of tran\gemc P3OlL ammal\. The phenotype of ammals expressmg P3OlL mutant tau contam the key feature\ ot FTDP-I7 and related tauopathies, making them excellent models for the wdy of neurodegeneratlon and lilu deposItion.