Taub Institute: Genomics Core
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TaubCONNECT Research Perspectives:
April 2016

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» #1 PDE5 Exists in Human Neurons and is a Viable Therapeutic Target for Neurologic Disease

» #2 PP2A Methylation Controls Sensitivity and Resistance to β-Amyloid–Induced Cognitive and Electrophysiological Impairments

» #1 Tau-driven 26S Proteasome Impairment and Cognitive Dysfunction can be Prevented Early in Disease by Activating cAMP-PKA Signaling

» #2 Older Adults with Poor Self-rated Memory have less Depressive Symptoms and Better Memory Performance when Perceived Self-efficacy is High

» #1 Extracellular Tau Oligomers Produce An Immediate Impairment of LTP and Memory

» #2 Examining the Pathways Between Self-Awareness and Well-Being in Mild to Moderate Alzheimer Disease

» #3 Mediterranean Diet and Brain Structure in a Multiethnic Elderly Cohort

» #1 Progression of Extrapyramidal Signs in Alzheimer's Disease: Clinical and Neuropathological Correlates

» #2 Telomere Longitudinal Shortening as a Biomarker for Dementia Status of Adults With Down Syndrome

» #1 The Reference Ability Neural Network Study: Life-time stability of reference-ability neural networks derived from task maps of young adults

» #2 Novel Selective Calpain 1 Inhibitors as Potential Therapeutics in Alzheimer's Disease

» #1 First Place: DREADDs Activation in the Medial Entorhinal Cortex (MEC) of EC-Tau Mice

» #1 First Place: Amyloid Precursor Protein (APP) is Ubiquitinated at Multiple Sites in the COOH-Terminal Domain as a Signal for Endosomal Sorting

» #1 F-box/LRR-repeat protein 7 is genetically associated with Alzheimer's disease

» #2 The keystone of Alzheimer pathogenesis might be sought in Aβ physiology

» #1 Stereotaxic Infusion of Oligomeric Amyloid-beta into the Mouse Hippocampus

» #2 Brain Amyloid Deposition and Longitudinal Cognitive Decline in Nondemented Older Subjects: Results from a Multi-Ethnic Population

» #1 Candidate genes for Alzheimer's disease are associated with individual differences in plasma levels of beta amyloid peptides in adults with Down syndrome

» #2 Gene-Wise Association of Variants in Four Lysosomal Storage Disorder Genes in Neuropathologically Confirmed Lewy Body Disease

» #1 SUMO1 Affects Synaptic Function, Spine Density and Memory

» #2 Connectivity and Circuitry in a Dish Versus in a Brain

» #1 Making Cognitive Latent Variables Manifest: Distinct Neural Networks For Fluid Reasoning And Processing Speed

» #2 Functional Network Mediates Age-related Differences in Reaction Time: a Replication and Extension Study

» #3 Self-Efficacy Buffers the Relationship between Educational Disadvantage and Executive Functioning

» #1 Specific Downregulation of Hippocampal ATF4 Reveals a Necessary Role in Synaptic Plasticity and Memory

» #2 Mediterranean Diet and Leukocyte Telomere Length in a Multi-ethnic Elderly Population

» #1 Cerebellum can serve as a pseudo-reference region in Alzheimer's disease to detect neuroinflammation measured with PET radioligand binding to translocator protein (TSPO)

» #2 Assembly and Interrogation of Alzheimer's Disease Genetic Networks Reveal Novel Regulators of Progression

» Neurotherapeutics: Rethinking Alzheimer's Disease Therapies

» #1 Dysregulation of microRNA-219 promotes neurodegeneration through post-transcriptional regulation of tau

» #2 Olfactory deficits predict cognitive decline and Alzheimer dementia in an urban community

» #3 Increased permeability-glycoprotein inhibition at the human blood-brain barrier can be safely achieved by performing PET during peak plasma concentrations of tariquidar

» Regulation of synaptic plasticity and cognition by SUMO in normal physiology and Alzheimer's disease

» Lobar Microbleeds Are Associated with a Decline in Executive Functioning in Older Adults

» Targeting Axonal Protein Synthesis in Neuroregeneration and Degeneration

» Inbreeding among Caribbean Hispanics from the Dominican Republic and its effects on risk of Alzheimer disease

» Coding mutations in SORL1 and Alzheimer's disease

» First Place: Pathogenic Role of Formin-mediated Stable Detyrosinated
     Microtubule Inductionby Amyloid beta

» First Place: Differential responsiveness to entorhinal cortical input distinguishes CA1 pyramidal neuron subpopulations

» Soluble amyloid beta levels are elevated in the white matter of Alzheimer's patients, independent of cortical plaque severity

» A Time Course Analysis of the Electrophysiological Properties of Neurons Differentiated from Human Induced Pluripotent Stem Cells (iPSCs)

» Axonally Synthesized ATF4 Transmits a Neurodegenerative Signal across Brain Regions

» Olfactory Dysfunction in the Elderly: Basic Circuitry and Alterations with Normal Aging and Alzheimer's Disease

» Neurological disorders: Quality-control pathway unlocked

» Estrogen Receptor α Variants Modify Risk for Alzheimer's Disease in a Multiethnic Female Cohort

» Combined suppression of CASP2 and CASP6 protects retinal ganglion cells from apoptosis and promotes axon regeneration through CNTF-mediated JAK/STAT signalling and Guidelines

» Local synthesis of TC10 is required for membrane expansion during axon outgrowth

» Dynamin 1 is Required for Memory Formation

» Behavioral Assays with Mouse Models of Alzheimer's Disease: Practical Considerations and Guidelines

» Biobanked Alzheimer's Brain Tissue Yields Living Neurons

» Picomolar Amyloid-ß Peptides Enhance Spontaneous Astrocyte Calcium Transients

White Matter Hyperintensities are a Core Feature of Alzheimer's Disease: Evidence From the Dominantly Inherited Alzheimer Network

Adam M. Brickman, PhD    Seonjoo Lee, PhD

White matter hyperintensities (WMH) are areas of increased signal visualized on certain types of magnetic resonance imaging (MRI) scans of the brain. They are thought to reflect small vessel cerebrovascular disease. Previous work from Dr. Brickman's laboratory and others has shown that the severity of WMH is associated with risk, onset, and progression of Alzheimer's disease (AD). These observations are often interpreted as evidence that small vessel cerebrovascular disease plays an additive role in clinical AD, contributing to the severity of symptomatology but not to the pathogenesis of the disease. However, there is considerable debate on the subject, with viable theoretical models that implicate a role of small vessel cerebrovascular abnormalities in AD pathogenesis, as well as emerging research suggesting interactions between WMH and primary AD pathology.

The study of the emergence of WMH, or any biological markers, and their contributions to AD in humans is difficult because the ordering and timing of the biological changes that lead to dementia can occur up to decades before the onset of symptoms. Furthermore, WMH are also tightly linked to vascular risk factors and age, so determination of their contribution to AD is potentially confounded by these factors. To overcome these issues, Dr. Brickman and colleagues turned to the landmark Dominantly Inherited Alzheimer Network (DIAN) study, which enrolls individuals at 50% risk for autosomal dominant AD by virtue of having a first-degree relative with a pathogenic mutation in one of three AD-causing genes (APP, PSEN1, or PSEN2). The purpose of the study was to examine the severity and distribution of WMH in presymptomatic mutation carriers to determine the extent to which WMH manifest in individuals genetically determined to develop AD. The study included 299 individuals (mean age=39-years-old) in whom 61.5% had a mutation that results in AD and 38.5% were first-degree relatives who were noncarrier controls. The estimated number of years to symptom onset was estimated by subtracting the affected parent's symptom onset age from the participant's age. Baseline MRI scans were analyzed for total and regional WMH and statistical models were constructed to examine WMH differences between mutation carriers and noncarriers with respect to the estimated number of years to symptom onset.

Figure 1. Examples of WMH distribution in mutation carriers (upper row) and non-carriers (lower row) across three EYO time points. The top row displays examples of T2-weighted FLAIR MRI scans from three mutation carriers at varying estimated years from symptom onset. The bottom row displays examples of MRI scans from non-carriers matched for estimated years from symptom onset (based on parental age of onset). All participants displayed in this figure had CDR scores of 0 at the time of MRI scan.

Recently published in the Annals of Neurology, results from the study showed that mutation carriers had greater total WMH volumes, which appeared to increase approximately 6 years prior to expected symptom onset. When examining the distribution of WMH regionally, the effects were most prominent in the parietal and occipital lobes, which showed divergent effects as early as 22 years before expected symptom onset. The findings demonstrate that autosomal-dominant AD is associated with increased WMH well before expected symptom onset, and suggest the possibility that small vessel cerebrovascular disease is a core feature of AD, a potential therapeutic target, and a factor that should be integrated in pathogenic models of the disease.

Figure 2. Association between estimated year from symptom onset and total WMH volume in mutation carriers and non-carriers. Mutation carriers had greater total WMH volume; differences in WMH volume between groups began increasing systematically approximately 6.6 years prior to estimated symptom onset (inflection point: -6.6 EYO, indicated by arrow on x-axis). Shaded areas represent 95% confidence intervals. Arrow indicates the inflection point in the analysis. IHS=inverse hyperbolic sine transformation.

Adam M. Brickman, PhD
Associate Professor of Neuropsychology (in Neurology, the Taub Institute, and the Gertrude H. Sergievsky Center)

Seonjoo Lee, PhD
Assistant Professor of Clinical Biostatistics (in Psychiatry)

Parkinson's Disease: Guilt by Genetic Association

Asa Abeliovich, MD, PhD    Herve Rhinn, PhD

In a brief review in Nature, Drs. Asa Abeliovich and Herve Rhinn discuss the utility of a sophisticated gene editing technology, termed CRISPR-Cas9, in the analysis of mechanisms of complex diseases such as Parkinson's disease (PD). Genome wide association studies from groups including Taub faculty members Drs. Lorraine Clark, Karen Marder, and many others have identified common variants (single nucleotide polymorphisms [SNPs], present in over ~5% of a population) across the human genome that are associated with disease risk, but just what these variants due has been difficult to parse. These studies present a number of challenges. For instance, swaths of the human genome are co-inherited across generations and typically include many common variants, and it is difficult to distinguish innocent bystanders that are co-inherited within such blocks of human genome from the truly causative genomic variants. Furthermore, the effects of such variants on human disease risk are typically pretty modest.

CRISPR-Cas9 technology in human embryonic stem (ES) cells offers a potential approach to very precisely modify the genome at a single variant and then determine the consequence. Abeliovich and Rhinn describe work from Rudy Jaenisch's lab which is focused on variants near the 3' end of the a-Synuclein gene. These are among the most strongly associated with PD across the human genome. aSynuclein protein is known to accumulate in PD brain, and the Jaenisch group focused on SNPs within the aSynuclein gene that have previously been shown to harbor epigenetic markings consistent with gene regulatory elements in human brain DNA. Using CRISPR-Cas9 technology, the Jaenisch group succeeded in converting human ES cells from the low-risk to the high-risk variant at a single suspected causative risk SNP, and showed that this led to a significant increase in gene expression. They, therefore, hypothesize that this SNP is part of the mechanism by which risk variants at the locus lead to an increase in disease risk. However, the work also clearly shows that other mechanisms must be at play, and this is an active area of research.

Figure. At one nucleotide in a non-protein-coding region of SNCA, the gene that encodes α-synuclein, the presence of the base adenine (A) is protective against Parkinson's disease, whereas the presence of another, guanine (G), confers increased risk. Soldner et al.3 report that this region regulates SNCA expression levels. If the two copies of the chromosome in a human cell each contain a different base at this site, gene expression is significantly higher from the risk-variant chromosome, owing in part to a reduction in the attachment of DNA-binding proteins that inhibit transcription. Using CRISPR–Cas9 gene-editing technology to remove the G and replace it with A reduces SNCA expression.

Asa Abeliovich, MD, PhD
Associate Professor of Pathology and Cell Biology, and Neurology (in the Taub Institute)

Herve Rhinn, PhD
Assistant Professor of Pathology and Cell Biology

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