- Email: [email protected]
NOVEL MISSENSE VARIANT ON EPHA1 IN A PROTECTED APOE4 FAMILY
Poster Presentations: Monday, July 17, 2017 Jo Thompson-Coon2, David J. Llewellyn1, 1University of Exeter Medical School, Exeter, United Kingdom; 2PenCLAHRC, University of Exeter Medical School, Exeter, United Kingdom. Contact e-mail: [email protected]
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and easy access to dementia-specific synthesized evidence in a single place. We are continuously working on improving the efficiency, sustainability and accessibility of EMANATE and aim to develop a publicly available web-based resource.
Background: Systematic reviews of randomized controlled trials and
other high quality studies are crucial to policy and evidence-based medicine. Systematic reviews synthesize and critically appraise burgeoning areas of investigation to make them digestible to a variety of audiences. However, the number of systematic reviews is increasing rapidly and they can be challenging to identify. To improve the accessibility of this information we developed EMANATE: a searchable database of all published systematic reviews and meta-analyses relevant to dementia. Methods: Initial database searches of MEDLINE, EMBASE, PsycINFO, CINAHL and the Cochrane Database of Systematic Reviews (CDSR) were conducted from inception until August 2016, using a combination of keywords and subject headings for dementia and systematic reviews without date or language restrictions. Titles and abstracts were independently screened for inclusion by two pairs of reviewers. Full-text were obtained for records where eligibility could not be determined based on title and abstract, and any discrepancies were resolved by discussion with a third reviewer. We included only completed systematic reviews with a defined research question, explicitly described search strategy, and defined inclusion and exclusion criteria assessing evidence related to dementia (including all-cause dementia, dementia subtypes, mild cognitive impairment, global and domain-specific cognition, and subjective cognitive complaints). Review protocols, narrative reviews and meeting abstracts were excluded. Results: We initially screened titles and abstracts of 23,607 records. We included 2,302 systematic reviews based on title and abstract screening, and identified 376 further records for full-text review (see Figure). The database is being continually updated through biannual database searches and automated daily search alerts set up for MEDLINE, CINAHL, and CDSR. At present, more than 2,350 systematic reviews are included in EMANATE with around 700 including a meta-analysis. EMANATE is currently available to interested researchers as an EndNote library. Conclusions: EMANATE is a rich source for researchers, funders, clinicians and policymakers that offers quick
P2-095
ANALYSIS OF NEURODEGENERATIVE DISEASE-RELATED PATHOLOGY IN THE RETINA AND OLFACTORY BULB OF RODENT MODELS
Joerg Neddens, Ainara Lopez-Pardo, Stefanie Flunkert, Birgit HutterPaier, Vera Niederkofler, QPS Austria, Grambach, Austria. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is the most common form of neurodegenerative dementia. Major hallmarks of the disease are extracellular plaque deposits of the b-amyloid peptide (Ab) and formation of intracellular neurofibrillary tangles, composed of tau protein in the brain tissue. Previous studies have reported the implication of functional impairments of the sensory systems in AD. In fact, retinal structural deficits and visual dysfunctions are often experienced by AD patients providing an opportunity to track this disease in the retina. This study aims to analyze the neuropathological changes occurring both in brain and retina of different AD animal models and address suitable biomarkers for early screening tests for AD. Methods: Eyes and brains from various AD animal models (APP rat, TAU rat, TMHT mouse) aged 6 and 12 months are collected. Right eyes and hemibrains are cryosectioned for immunohistochemical labelling, while left eyes and hemibrains are frozen for further biochemical and molecular characterization. For immunohistochemical analysis, a range of antibodies have been employed to detect and quantitatively analyze different neuropathological markers present in retina, primary and secondary visual cortex (visual system), as well as in the olfactory bulb and piriform cortex (olfactory system). Results: AD rodent models show a significant agedependent shift in neuropathology-related biomarkers when compared to controls, although the results might vary due to the existing biological differences between mice and rats, and retina and brain tissue. In all sections, an overall increase in Ab and tau protein is expected (Amyloid, Tau). Additional analyses will focus on different neurotransmitters (chAT, GAD67, TH), neuronal cells, glial cells and synapses (NeuN, GFAP, F4/80, PSD95, Piccolo). Conclusions: Our results will strengthen the hypothesis that AD manifests in eyes, particularly the retina, and provide evidence for the possibility to track the disease utilizing the appropriate AD biomarkers.
P2-096
NOVEL MISSENSE VARIANT ON EPHA1 IN A PROTECTED APOE4 FAMILY
Raiyan R. Khan1, Andre Altmann2, Lily H. Kim1, Julien Couthouis1, Valerio Napolioni1, Aaron D. Gitler1, Michael D. Greicius1, 1Stanford University School of Medicine, Stanford, CA, USA; 2Translational Imaging Group, Centre for Medical Image Computing, University College London, London, United Kingdom. Contact e-mail: [email protected] Background: The APOE4 allele is the strongest common genetic
Figure. EMANATE study selection flow diagram.
risk factor for sporadic Alzheimer’s disease (AD), increasing risk roughly 3-fold in heterozygotes and 8-fold in homozygotes. Here we report a family in which the index case (APOE3/4) developed AD at 56 while her mother (APOE4/4) and maternal uncle (APOE3/4) remain cognitively well at ages 77 and 79, respectively. Given that the mother was APOE4 homozygous but unaffected, we undertook a search for putative, protective variants. Methods: The
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Poster Presentations: Monday, July 17, 2017
Figure 1. Pedigree of the family investigated in this study. The index case has sporadic AD and no other causes of cognitive impairment. All members of generation II were confirmed normal on assessment. Information on generation I was by family report. The sib-pair are c.2279A>C EPHA1 heterozygotes.
maging Initiative. Variants not found in any cases were annotated using the Ensembl Variant Effect Predictor toolset. Results: Analysis disclosed the presence of the variant NM_005232.4: c.2279A>C (p.Asn760Thr) on exon 14 of the EPHA1 gene in the mother and maternal uncle. The variant was not found in the 1000 Genomes, ExAC, ALS, or Geno2MP databases. Polyphen2, an in silico prediction tool, suggests that the effect of the variant is likely benign (0.099). Conclusions: The presence of this EPHA1 variant in a healthy older APOE4 homozygote and APOE4 heterozgyote sib-pair combined with its absence in the related index case and in nearly 6,000 AD cases, suggests that it may be a private, protective variant. A common, protective polymorphism on EPHA1 has been reproducibly identified in large genome-wide association studies. Additional screening of this family is underway and functional assays will be undertaken on neurons derived from fibroblasts donated by the mother and affected daughter.
P2-097
WITHDRAWN
P2-098
TSPO IMMUNOSTAINING IN AD CASES WITH/WITHOUT AN AD-ASSOCIATED TREM2 VARIANT
Angela Hodges1,2, Yau Mun Lim3, 1Maurice Wohl Clinical Neuroscience Institute James Black Centre Institute of Psychiatry, Psychology & Neuroscience (IoPPN) King’s College London, London, United Kingdom; 2King’s College London, London, United Kingdom; 3King’s College London, Institute of Psychiatry, Psychology & Neuroscience, London, United Kingdom. Contact e-mail: [email protected]
Figure 2. Reported cerebrospinal fluid levels of Ab42 peptide, total tau (T-tau), and phospho-tau (P-tau) protein in the index case are consistent with the diagnosis of AD. (A) Technical results reported from Athena Diagnostics. (B) Subject data is plotted on the graph to illustrate the position of the individual’s results relative to recognized reference points for diagnostic cutoff values.
index case exhibited a typical amnestic presentation of AD and underwent spinal fluid analysis for AD biomarkers, which strongly supported the diagnosis. The mother underwent research clinical and neuropsychological evaluations confirming her to be cognitively healthy. The uncle underwent a phone interview with a CDR of 0. Whole exome sequencing was performed on all family members on the Illumina HiSeq2000 platform. The raw data was analyzed with BWA (read mapping) and GATK (variant calling) software packages. Variants were filtered to select mutations present in only the mother and uncle, but not the daughter. These variants were then screened against 5,656 AD cases from the Alzheimer’s Disease Sequencing Project, and 128 AD cases with whole genome sequencing from the Alzheimer’s Disease Neuroi-
Background: The Peripheral-Type Benzodiazepine Receptor (TSPO) is a well-established target for the Positron Emission Tomography (PET) ligands [11C]-PK11195 and [11C]-PBR28. TSPO is believed to translocate cholesterol across the mitochondrial intermembrane space and is highly expressed in activated glia. TSPO PET ligands thus enable sensitive in vivo monitoring of neuroinflammation, a phenomenon closely associated with neuronal cell death in Alzheimer’s disease (AD). AD patients have recently been identified with rare disease-associated variants in the TREM2 gene (1, 2). Disease vulnerability in these people appears to be linked to inappropriate microglial function and immune response. TREM2 is a plasma membrane receptor highly expressed in brain microglia (3) where it is believed to regulate phagocytic and inflammatory microglial responses to brain pathology. We therefore sought to establish if TSPO levels are impaired in AD patients who have a disease-associated TREM2 variant and establish which glial cells impairment is associated. Methods: Hippocampal sections (5-7mM) from age and gender matched AD (N¼37) and control (N¼18) donors were analysed by immunohistochemistry using published TSPO antibodies (4, 5) (PAB7095 and NP155). The AD cases consisted of Braak-matched cases (IV) with TREM2+ (N¼16) and without TREM2-(N¼21) disease-associated variants in TREM2. Sections were also immunostained for p-tau (AT8), Ab (4G8) and by co-immunoflurescence with markers of microglia (Iba-1, CD68 and HLA-DR,DP,DQ) and astrocytes (GFAP) to ascertain cell types expressing TSPO. Results: We will report results of
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and easy access to dementia-specific synthesized evidence in a single place. We are continuously working on improving the efficiency, sustainability and accessibility of EMANATE and aim to develop a publicly available web-based resource.
Background: Systematic reviews of randomized controlled trials and
other high quality studies are crucial to policy and evidence-based medicine. Systematic reviews synthesize and critically appraise burgeoning areas of investigation to make them digestible to a variety of audiences. However, the number of systematic reviews is increasing rapidly and they can be challenging to identify. To improve the accessibility of this information we developed EMANATE: a searchable database of all published systematic reviews and meta-analyses relevant to dementia. Methods: Initial database searches of MEDLINE, EMBASE, PsycINFO, CINAHL and the Cochrane Database of Systematic Reviews (CDSR) were conducted from inception until August 2016, using a combination of keywords and subject headings for dementia and systematic reviews without date or language restrictions. Titles and abstracts were independently screened for inclusion by two pairs of reviewers. Full-text were obtained for records where eligibility could not be determined based on title and abstract, and any discrepancies were resolved by discussion with a third reviewer. We included only completed systematic reviews with a defined research question, explicitly described search strategy, and defined inclusion and exclusion criteria assessing evidence related to dementia (including all-cause dementia, dementia subtypes, mild cognitive impairment, global and domain-specific cognition, and subjective cognitive complaints). Review protocols, narrative reviews and meeting abstracts were excluded. Results: We initially screened titles and abstracts of 23,607 records. We included 2,302 systematic reviews based on title and abstract screening, and identified 376 further records for full-text review (see Figure). The database is being continually updated through biannual database searches and automated daily search alerts set up for MEDLINE, CINAHL, and CDSR. At present, more than 2,350 systematic reviews are included in EMANATE with around 700 including a meta-analysis. EMANATE is currently available to interested researchers as an EndNote library. Conclusions: EMANATE is a rich source for researchers, funders, clinicians and policymakers that offers quick
P2-095
ANALYSIS OF NEURODEGENERATIVE DISEASE-RELATED PATHOLOGY IN THE RETINA AND OLFACTORY BULB OF RODENT MODELS
Joerg Neddens, Ainara Lopez-Pardo, Stefanie Flunkert, Birgit HutterPaier, Vera Niederkofler, QPS Austria, Grambach, Austria. Contact e-mail: [email protected] Background: Alzheimer’s disease (AD) is the most common form of neurodegenerative dementia. Major hallmarks of the disease are extracellular plaque deposits of the b-amyloid peptide (Ab) and formation of intracellular neurofibrillary tangles, composed of tau protein in the brain tissue. Previous studies have reported the implication of functional impairments of the sensory systems in AD. In fact, retinal structural deficits and visual dysfunctions are often experienced by AD patients providing an opportunity to track this disease in the retina. This study aims to analyze the neuropathological changes occurring both in brain and retina of different AD animal models and address suitable biomarkers for early screening tests for AD. Methods: Eyes and brains from various AD animal models (APP rat, TAU rat, TMHT mouse) aged 6 and 12 months are collected. Right eyes and hemibrains are cryosectioned for immunohistochemical labelling, while left eyes and hemibrains are frozen for further biochemical and molecular characterization. For immunohistochemical analysis, a range of antibodies have been employed to detect and quantitatively analyze different neuropathological markers present in retina, primary and secondary visual cortex (visual system), as well as in the olfactory bulb and piriform cortex (olfactory system). Results: AD rodent models show a significant agedependent shift in neuropathology-related biomarkers when compared to controls, although the results might vary due to the existing biological differences between mice and rats, and retina and brain tissue. In all sections, an overall increase in Ab and tau protein is expected (Amyloid, Tau). Additional analyses will focus on different neurotransmitters (chAT, GAD67, TH), neuronal cells, glial cells and synapses (NeuN, GFAP, F4/80, PSD95, Piccolo). Conclusions: Our results will strengthen the hypothesis that AD manifests in eyes, particularly the retina, and provide evidence for the possibility to track the disease utilizing the appropriate AD biomarkers.
P2-096
NOVEL MISSENSE VARIANT ON EPHA1 IN A PROTECTED APOE4 FAMILY
Raiyan R. Khan1, Andre Altmann2, Lily H. Kim1, Julien Couthouis1, Valerio Napolioni1, Aaron D. Gitler1, Michael D. Greicius1, 1Stanford University School of Medicine, Stanford, CA, USA; 2Translational Imaging Group, Centre for Medical Image Computing, University College London, London, United Kingdom. Contact e-mail: [email protected] Background: The APOE4 allele is the strongest common genetic
Figure. EMANATE study selection flow diagram.
risk factor for sporadic Alzheimer’s disease (AD), increasing risk roughly 3-fold in heterozygotes and 8-fold in homozygotes. Here we report a family in which the index case (APOE3/4) developed AD at 56 while her mother (APOE4/4) and maternal uncle (APOE3/4) remain cognitively well at ages 77 and 79, respectively. Given that the mother was APOE4 homozygous but unaffected, we undertook a search for putative, protective variants. Methods: The
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Poster Presentations: Monday, July 17, 2017
Figure 1. Pedigree of the family investigated in this study. The index case has sporadic AD and no other causes of cognitive impairment. All members of generation II were confirmed normal on assessment. Information on generation I was by family report. The sib-pair are c.2279A>C EPHA1 heterozygotes.
maging Initiative. Variants not found in any cases were annotated using the Ensembl Variant Effect Predictor toolset. Results: Analysis disclosed the presence of the variant NM_005232.4: c.2279A>C (p.Asn760Thr) on exon 14 of the EPHA1 gene in the mother and maternal uncle. The variant was not found in the 1000 Genomes, ExAC, ALS, or Geno2MP databases. Polyphen2, an in silico prediction tool, suggests that the effect of the variant is likely benign (0.099). Conclusions: The presence of this EPHA1 variant in a healthy older APOE4 homozygote and APOE4 heterozgyote sib-pair combined with its absence in the related index case and in nearly 6,000 AD cases, suggests that it may be a private, protective variant. A common, protective polymorphism on EPHA1 has been reproducibly identified in large genome-wide association studies. Additional screening of this family is underway and functional assays will be undertaken on neurons derived from fibroblasts donated by the mother and affected daughter.
P2-097
WITHDRAWN
P2-098
TSPO IMMUNOSTAINING IN AD CASES WITH/WITHOUT AN AD-ASSOCIATED TREM2 VARIANT
Angela Hodges1,2, Yau Mun Lim3, 1Maurice Wohl Clinical Neuroscience Institute James Black Centre Institute of Psychiatry, Psychology & Neuroscience (IoPPN) King’s College London, London, United Kingdom; 2King’s College London, London, United Kingdom; 3King’s College London, Institute of Psychiatry, Psychology & Neuroscience, London, United Kingdom. Contact e-mail: [email protected]
Figure 2. Reported cerebrospinal fluid levels of Ab42 peptide, total tau (T-tau), and phospho-tau (P-tau) protein in the index case are consistent with the diagnosis of AD. (A) Technical results reported from Athena Diagnostics. (B) Subject data is plotted on the graph to illustrate the position of the individual’s results relative to recognized reference points for diagnostic cutoff values.
index case exhibited a typical amnestic presentation of AD and underwent spinal fluid analysis for AD biomarkers, which strongly supported the diagnosis. The mother underwent research clinical and neuropsychological evaluations confirming her to be cognitively healthy. The uncle underwent a phone interview with a CDR of 0. Whole exome sequencing was performed on all family members on the Illumina HiSeq2000 platform. The raw data was analyzed with BWA (read mapping) and GATK (variant calling) software packages. Variants were filtered to select mutations present in only the mother and uncle, but not the daughter. These variants were then screened against 5,656 AD cases from the Alzheimer’s Disease Sequencing Project, and 128 AD cases with whole genome sequencing from the Alzheimer’s Disease Neuroi-
Background: The Peripheral-Type Benzodiazepine Receptor (TSPO) is a well-established target for the Positron Emission Tomography (PET) ligands [11C]-PK11195 and [11C]-PBR28. TSPO is believed to translocate cholesterol across the mitochondrial intermembrane space and is highly expressed in activated glia. TSPO PET ligands thus enable sensitive in vivo monitoring of neuroinflammation, a phenomenon closely associated with neuronal cell death in Alzheimer’s disease (AD). AD patients have recently been identified with rare disease-associated variants in the TREM2 gene (1, 2). Disease vulnerability in these people appears to be linked to inappropriate microglial function and immune response. TREM2 is a plasma membrane receptor highly expressed in brain microglia (3) where it is believed to regulate phagocytic and inflammatory microglial responses to brain pathology. We therefore sought to establish if TSPO levels are impaired in AD patients who have a disease-associated TREM2 variant and establish which glial cells impairment is associated. Methods: Hippocampal sections (5-7mM) from age and gender matched AD (N¼37) and control (N¼18) donors were analysed by immunohistochemistry using published TSPO antibodies (4, 5) (PAB7095 and NP155). The AD cases consisted of Braak-matched cases (IV) with TREM2+ (N¼16) and without TREM2-(N¼21) disease-associated variants in TREM2. Sections were also immunostained for p-tau (AT8), Ab (4G8) and by co-immunoflurescence with markers of microglia (Iba-1, CD68 and HLA-DR,DP,DQ) and astrocytes (GFAP) to ascertain cell types expressing TSPO. Results: We will report results of