- Email: [email protected]
Accelerated lipofuscinosis and ubiquitination in granulin knockout mice suggests a role for progranulin in successful aging
Oral O1-07: Frontotemporal Dementia dementia incidence. This study estimates the percentage reduction in disease incidence which would be obtained if specific exposures were completely eliminated. Methods: Data for the study were obtained from a prospective 7 year general population cohort study of 1,433 persons over 65 with a mean baseline age of 72.5 (SD ¼ 5.1) Diagnosis of mild cognitive impairment (MCI) or dementia was established by a standardized neurological examination. Results: Potentially modifiable risk factors for dementia were identified from previous epidemiological and clinical studies. Cox models were constructed to derive hazards ratios and determine confounding and interaction effects for potentially modifiable dementia risk factors. Mean % Population Attributable Fractions (PAF) were calculated with 95% confidence intervals derived from bootstrapping for seven year MCI or dementia incidence. The final model retained cognitive activity, (PAF ¼ 18.11 ; 10.91 to 25.42), depression (PAF ¼ 10.31 ; 3.66 to17.17), fruit and vegetable consumption (PAF ¼ 6.46 ; 0.15 to 13.06), diabetes (PAF ¼ 4.88 ; 1.87 to 7.98) and ApoE e4 allele (PAF ¼ 7.11 ; 2.44 to 11.98). Conclusions: Increasing cognitive activity levels and fruit and vegetable consumption, and eliminating depression and diabetes, are likely to have the biggest impact on reducing dementia incidence, outweighing even the impact of removing the principal known genetic risk factor. While these estimates are based on global indicators, they suggest a hierarchy of priorities which may inform public health programs. O1-06-08
NON-STEROIDAL ANTI-INFLAMMATORY DRUGS ARE ASSOCIATED WITH INCREASED NEURITIC PLAQUES
Joshua A. Sonnen1, Eric B. Larson2, Rod Walker2, Sebastien Haneuse3, Paul K. Crane1, Shelly L. Gray1, John C. S. Breitner1, Thomas J. Montine1, 1 University of Washington, Seattle, WA, USA; 2Group Health Research Institute, Seattle, WA, USA; 3Group Health Reseach Institute, Seattle, WA, USA. Contact e-mail: [email protected] Background: Some observational and experimental studies suggest that non-steroidal anti-inflammatory drugs (NSAIDs) may protect against dementia from Alzheimer’s disease (AD); however, clinical trials and other observational studies, including one from the Adult Changes in Thought (ACT) study, show no such protection or even apparent promotion of AD dementia. The objective of this study is to determine the relationship between the common dementia associated pathologies and mid- to late-life NSAID exposure in the ACT cohort. Methods: We examined the association of mid- to latelife NSAIDs use with the neuropathological findings on 257 autopsied participants from ACT, a population-based study of brain aging and incident dementia in the Seattle metropolitan area. Cumulative standard daily doses (SDD) of non-selective NSAIDs were determined from 10 years of computerized pharmacy dispensing data. Analyses were adjusted for selection bias to broaden generalizability of results to the 3,026 eligible participants in the ACT cohort. Six pathologic indices were evaluated: ‘‘intermediate’’ or ‘‘frequent’’ score for neuritic plaques (NPs); Braak stages V or VI for neurofibrillary tangles; >2 cerebral microinfarcts; the presence of any neocortical Lewy bodies; any macroscopic infarcts; any amyloid angiopathy. Results: Of the neuropathologic indices evaluated, only NP score was increased in participants with greater use of non-selective NSAIDs (p ¼ 0.031), specifically in those with 1000 - 2000 SDD (p ¼ 0.021) and >2000 SDD (p ¼ 0.005). Conclusions: Increased NP accumulation may explain the association between heavy use of non-selective NSAIDs and increased risk for dementia among ACT participants. SUNDAY, JULY 11, 2010 ORAL O1-07 FRONTOTEMPORAL DEMENTIA O1-07-01
ACCELERATED LIPOFUSCINOSIS AND UBIQUITINATION IN GRANULIN KNOCKOUT MICE SUGGESTS A ROLE FOR PROGRANULIN IN SUCCESSFUL AGING
Zeshan Ahmed1, Hong Sheng1, Ya-fei Xu1, Wen-Lang Lin1, Amy E. Innes1, Xin Yu1, Harold Hou1, Shuichi Chiba2,
S83
Keitaro Yamanouchi2, Leonard Petrucelli1, Masugi Nishihara2, Michael L. Hutton1, Eileen McGowan1, Dennis W. Dickson1, Jada Lewis1, 1 Mayo Clinic College of Medicine, Jacksonville, FL, USA; 2University of Tokyo, Tokyo, Japan. Contact e-mail: [email protected] Background: Progranulin (PGRN) is involved in wound repair, inflammation and tumor formation, but its function in the CNS is unknown. Roles in development, sexual differentiation and long-term neuronal survival have been suggested. Mutations in the GRN gene resulting in partial loss of the encoded PGRN protein cause frontotemporal lobar degeneration with ubiquitin immunoreactive inclusions (FTLD-U). We sought to understand the neuropathological consequences of loss of PGRN function in GRN-deficient (-/+ and -/-) mice. Methods: An aged-series of GRN-deficient and wild-type mice was compared with histology, immunohistochemistry and electron microscopy (EM). Results: While GRN-deficient mice were viable, GRN-/- mice were produced at lower than predicted frequency. Neuropathologically, GRN+/- were indistinguishable from controls; whereas, GRN-/- mice developed age-associated, abnormal intraneuronal ubiquitin-positive autofluorescent lipofuscin. Ubiquitin-positive lipofuscin was noted in aged GRN+/+ mice at levels comparable to young GRN-/- mice. GRN-/- mice developed microgliosis, astrogliosis and tissue vacuolation, with focal neuronal loss and severe gliosis apparent in the oldest GRN-/- mice. Although no overt FTLD-U type lesions were observed in GRN-deficient mice even at 23 months of age, robust lipofuscinosis and ubiquitination in GRN-/- mice is strikingly similar to key changes associated with aging and cellular decline in both humans and animal models. Conclusions: Our data suggests that PGRN plays a key role in maintaining neuronal function during aging and supports the notion that PGRN is a trophic factor essential for long-term neuronal survival. O1-07-02
LOSS OF PROGRANULIN AND ITS IMPACT ON NEURONAL FUNCTION
Jennifer M. Gass, Casey Cook, Rosa Rademakers, Jada Lewis, Leonard Petrucelli, Mayo Clinic, Jacksonville, FL, USA. Contact e-mail: [email protected] Background: Frontotemporal lobar degeneration (FTLD) is the second most common form of presenile dementia after Alzheimer’s disease. FTLD is divided into two main subgroups: those with tau-positive pathology (FTDPtau), and those with TDP-43- and ubiquitin-positive, but tau- and a-synulcein-negative, pathology (FTLD-U). Null mutations in progranulin (PGRN) are a major cause of FTLD-U, creating premature termination of the coding sequence and degradation of the mutant RNA by nonsense-mediated decay resulting in a haploinsuffiency. Several missense mutations have been identified but are yet to be determined as pathogenic. Recent studies report that PGRN acts as a protective neurotrophic factor regulating neuronal survival and growth. However, little is known about its function in the CNS or its relation to neurodegeneration. Methods: To study the impact of loss of PGRN on neurodegeneration, we utilized murine PGRN knockout and wildtype primary hippocampal neurons. Primary neurons plated on coverslips were stained with MAP2 and analyzed by MetaMorph software to detect changes in neuronal morphology. To further examine the effects of PGRN using this model, we transduced these cultures with GFP, WT-PGRN, and missense mutated PGRN via adeno-associated virus (AAV). Results: We developed a primary cell culture model demonstrating that loss of PGRN in primary neurons produces morphological deficits when compared to wildtype neurons. These deficits were rescued by the overexpression of WTPGRN-AAV. In addition, pathogenicity of several missense mutations in PGRN were also analyzed using this novel model. Conclusions: We identified that loss of PGRN in primary neurons causes morphological changes which could explain how PGRN haploinsufficiency in patients leads to neurodegeneration. This data will shed further insight on the mechanisms underlying neurodegeneration due to mutations in PGRN, and provide information into the development of FTLD-U as well as other neurodegenerative diseases. Development of this model will be a useful tool allowing us to assess which PGRN mutations are pathogenic, how loss of PGRN may increase neuronal vulnerability to various cellular stressors and ultimately the functions of PGRN in the CNS.
NON-STEROIDAL ANTI-INFLAMMATORY DRUGS ARE ASSOCIATED WITH INCREASED NEURITIC PLAQUES
Joshua A. Sonnen1, Eric B. Larson2, Rod Walker2, Sebastien Haneuse3, Paul K. Crane1, Shelly L. Gray1, John C. S. Breitner1, Thomas J. Montine1, 1 University of Washington, Seattle, WA, USA; 2Group Health Research Institute, Seattle, WA, USA; 3Group Health Reseach Institute, Seattle, WA, USA. Contact e-mail: [email protected] Background: Some observational and experimental studies suggest that non-steroidal anti-inflammatory drugs (NSAIDs) may protect against dementia from Alzheimer’s disease (AD); however, clinical trials and other observational studies, including one from the Adult Changes in Thought (ACT) study, show no such protection or even apparent promotion of AD dementia. The objective of this study is to determine the relationship between the common dementia associated pathologies and mid- to late-life NSAID exposure in the ACT cohort. Methods: We examined the association of mid- to latelife NSAIDs use with the neuropathological findings on 257 autopsied participants from ACT, a population-based study of brain aging and incident dementia in the Seattle metropolitan area. Cumulative standard daily doses (SDD) of non-selective NSAIDs were determined from 10 years of computerized pharmacy dispensing data. Analyses were adjusted for selection bias to broaden generalizability of results to the 3,026 eligible participants in the ACT cohort. Six pathologic indices were evaluated: ‘‘intermediate’’ or ‘‘frequent’’ score for neuritic plaques (NPs); Braak stages V or VI for neurofibrillary tangles; >2 cerebral microinfarcts; the presence of any neocortical Lewy bodies; any macroscopic infarcts; any amyloid angiopathy. Results: Of the neuropathologic indices evaluated, only NP score was increased in participants with greater use of non-selective NSAIDs (p ¼ 0.031), specifically in those with 1000 - 2000 SDD (p ¼ 0.021) and >2000 SDD (p ¼ 0.005). Conclusions: Increased NP accumulation may explain the association between heavy use of non-selective NSAIDs and increased risk for dementia among ACT participants. SUNDAY, JULY 11, 2010 ORAL O1-07 FRONTOTEMPORAL DEMENTIA O1-07-01
ACCELERATED LIPOFUSCINOSIS AND UBIQUITINATION IN GRANULIN KNOCKOUT MICE SUGGESTS A ROLE FOR PROGRANULIN IN SUCCESSFUL AGING
Zeshan Ahmed1, Hong Sheng1, Ya-fei Xu1, Wen-Lang Lin1, Amy E. Innes1, Xin Yu1, Harold Hou1, Shuichi Chiba2,
S83
Keitaro Yamanouchi2, Leonard Petrucelli1, Masugi Nishihara2, Michael L. Hutton1, Eileen McGowan1, Dennis W. Dickson1, Jada Lewis1, 1 Mayo Clinic College of Medicine, Jacksonville, FL, USA; 2University of Tokyo, Tokyo, Japan. Contact e-mail: [email protected] Background: Progranulin (PGRN) is involved in wound repair, inflammation and tumor formation, but its function in the CNS is unknown. Roles in development, sexual differentiation and long-term neuronal survival have been suggested. Mutations in the GRN gene resulting in partial loss of the encoded PGRN protein cause frontotemporal lobar degeneration with ubiquitin immunoreactive inclusions (FTLD-U). We sought to understand the neuropathological consequences of loss of PGRN function in GRN-deficient (-/+ and -/-) mice. Methods: An aged-series of GRN-deficient and wild-type mice was compared with histology, immunohistochemistry and electron microscopy (EM). Results: While GRN-deficient mice were viable, GRN-/- mice were produced at lower than predicted frequency. Neuropathologically, GRN+/- were indistinguishable from controls; whereas, GRN-/- mice developed age-associated, abnormal intraneuronal ubiquitin-positive autofluorescent lipofuscin. Ubiquitin-positive lipofuscin was noted in aged GRN+/+ mice at levels comparable to young GRN-/- mice. GRN-/- mice developed microgliosis, astrogliosis and tissue vacuolation, with focal neuronal loss and severe gliosis apparent in the oldest GRN-/- mice. Although no overt FTLD-U type lesions were observed in GRN-deficient mice even at 23 months of age, robust lipofuscinosis and ubiquitination in GRN-/- mice is strikingly similar to key changes associated with aging and cellular decline in both humans and animal models. Conclusions: Our data suggests that PGRN plays a key role in maintaining neuronal function during aging and supports the notion that PGRN is a trophic factor essential for long-term neuronal survival. O1-07-02
LOSS OF PROGRANULIN AND ITS IMPACT ON NEURONAL FUNCTION
Jennifer M. Gass, Casey Cook, Rosa Rademakers, Jada Lewis, Leonard Petrucelli, Mayo Clinic, Jacksonville, FL, USA. Contact e-mail: [email protected] Background: Frontotemporal lobar degeneration (FTLD) is the second most common form of presenile dementia after Alzheimer’s disease. FTLD is divided into two main subgroups: those with tau-positive pathology (FTDPtau), and those with TDP-43- and ubiquitin-positive, but tau- and a-synulcein-negative, pathology (FTLD-U). Null mutations in progranulin (PGRN) are a major cause of FTLD-U, creating premature termination of the coding sequence and degradation of the mutant RNA by nonsense-mediated decay resulting in a haploinsuffiency. Several missense mutations have been identified but are yet to be determined as pathogenic. Recent studies report that PGRN acts as a protective neurotrophic factor regulating neuronal survival and growth. However, little is known about its function in the CNS or its relation to neurodegeneration. Methods: To study the impact of loss of PGRN on neurodegeneration, we utilized murine PGRN knockout and wildtype primary hippocampal neurons. Primary neurons plated on coverslips were stained with MAP2 and analyzed by MetaMorph software to detect changes in neuronal morphology. To further examine the effects of PGRN using this model, we transduced these cultures with GFP, WT-PGRN, and missense mutated PGRN via adeno-associated virus (AAV). Results: We developed a primary cell culture model demonstrating that loss of PGRN in primary neurons produces morphological deficits when compared to wildtype neurons. These deficits were rescued by the overexpression of WTPGRN-AAV. In addition, pathogenicity of several missense mutations in PGRN were also analyzed using this novel model. Conclusions: We identified that loss of PGRN in primary neurons causes morphological changes which could explain how PGRN haploinsufficiency in patients leads to neurodegeneration. This data will shed further insight on the mechanisms underlying neurodegeneration due to mutations in PGRN, and provide information into the development of FTLD-U as well as other neurodegenerative diseases. Development of this model will be a useful tool allowing us to assess which PGRN mutations are pathogenic, how loss of PGRN may increase neuronal vulnerability to various cellular stressors and ultimately the functions of PGRN in the CNS.