John M. Wells

Allele ε4 of Apolipoprotein E Shows a Dose Effect on Age at Onset of Pick Disease

Pick disease is a rare progressive dementing illness characterized by severe atrophy of the frontal and temporal lobes. Clinically, Pick disease may be difficult to distinguish from Alzheimer disease (AD). The fact that Pick disease is often familial, and the evidence suggesting that the ϵ4 allele of apolipoprotein E (ApoE) is a risk factor for AD and possibly other dementias, prompted us to study ApoE isoforms in Pick disease. ApoE genotypes were evaluated in an autopsy series of 21 AD and 12 Pick cases and compared with published data for a large group of adults participating in the Framingham Study. The distributions of ApoE genotypes in the AD and Pick patients and the controls were significantly different from one another. The frequency of ϵ4 was 50.0, 20.0, and 13.6% in these respective groups. Linear regression analysis showed that the number of ϵ4 alleles was inversely related to age at onset of Pick disease (P < 0.03) and accounted for 40% of the variation in age at onset. These results suggest that ϵ4 may be a susceptibility factor for dementia and not specifically for AD. Experiments using a monoclonal antibody against ApoE suggest that neurons and Pick bodies are immunoreactive with ApoE. The dose effect of the ϵ4 allele on age at onset of dementias other than AD and the association of ApoE immunoreactivity with neurons and Pick bodies support a broader role for ApoE in the pathogenesis of neuronal degeneration through interactions with the neuronal cytoskeleton.

Three Dimensional Human Neuro-Spheroid Model of Alzheimer's Disease Based on Differentiated Induced Pluripotent Stem Cells.

The testing of candidate drugs to slow progression of Alzheimer’s disease (AD) requires clinical trials that are lengthy and expensive. Efforts to model the biochemical milieu of the AD brain may be greatly facilitated by combining two cutting edge technologies to generate three-dimensional (3D) human neuro-spheroid from induced pluripotent stem cells (iPSC) derived from AD subjects. We created iPSC from blood cells of five AD patients and differentiated them into 3D human neuronal culture. We characterized neuronal markers of our 3D neurons by immunocytochemical staining to validate the differentiation status. To block the generation of pathologic amyloid β peptides (Aβ), the 3D-differentiated AD neurons were treated with inhibitors targeting β-secretase (BACE1) and γ-secretases. As predicted, both BACE1 and γ-secretase inhibitors dramatically decreased Aβ generation in iPSC-derived neural cells derived from all five AD patients, under standard two-dimensional (2D) differentiation conditions. However, BACE1 and γ-secretase inhibitors showed less potency in decreasing Aβ levels in neural cells differentiated under 3D culture conditions. Interestingly, in a single subject AD1, we found that BACE1 inhibitor treatment was not able to significantly reduce Aβ42 levels. To investigate underlying molecular mechanisms, we performed proteomic analysis of 3D AD human neuronal cultures including AD1. Proteomic analysis revealed specific reduction of several proteins that might contribute to a poor inhibition of BACE1 in subject AD1. To our knowledge, this is the first iPSC-differentiated 3D neuro-spheroid model derived from AD patients’ blood. Our results demonstrate that our 3D human neuro-spheroid model can be a physiologically relevant and valid model for testing efficacy of AD drug.

Induced pluripotent stem cells (iPSCs) derived from frontotemporal dementia patient's peripheral blood mononuclear cells

Peripheral blood mononuclear cells (PBMC) were donated by a patient with clinically diagnosed frontotemporal dementia (FTD). Induced pluripotent stem cells (iPSCs) were developed using integration-free CytoTune-iPS Sendai Reprogramming factors which include Sendai virus particles of the four Yamanaka factors Oct, Sox2, Klf4, and c-Myc.

Alcohol Consumption and Risk of Coronary Artery Disease (from the Million Veteran Program)

Moderate alcohol consumption has been associated with a lower risk of coronary artery disease (CAD) in the general population but has not been well studied in US veterans. We obtained self-reported alcohol consumption from Million Veteran Program participants. Using electronic health records, CAD events were defined as 1 inpatient or 2 outpatient diagnosis codes for CAD, or 1 code for a coronary procedure. We excluded participants with prevalent CAD (nu2009=u200969,995) or incomplete alcohol information (nu2009=u20098,449). We used a Cox proportional hazards model to estimate hazard ratios and 95% confidence intervals for CAD, adjusting for age, gender, body mass index, race, smoking, education, and exercise. Among 156,728 participants, the mean age was 65.3 years (standard deviationu2009=u200912.1) and 91% were men. There were 6,153 CAD events during a mean follow-up of 2.9 years. Adjusted hazard ratios (95% confidence intervals) for CAD were 1.00 (reference), 1.02 (0.92 to 1.13), 0.83 (0.74 to 0.93), 0.77 (0.67 to 0.87), 0.71 (0.62 to 0.81), 0.62 (0.51 to 0.76), 0.58 (0.46 to 0.74), and 0.95 (0.85 to 1.06) for categories of never drinker; former drinker; current drinkers of ≤0.5 drink/day, >0.5 to 1 drink/day, >1 to 2 drinks/day, >2 to 3 drinks/day, and >3 to 4 drinks/day; and heavy drinkers (>4 drinks/day) or alcohol use disorder, respectively. For a fixed amount of ethanol, intake at ≥3 days/week was associated with lower CAD risk compared with ≤1 day/week. Beverage preference (beer, wine, or liquor) did not influence the alcohol-CAD relation. Our data show a lower risk of CAD with light-to-moderate alcohol consumption among US veterans, and drinking frequency may provide a further reduction in risk.

Retromer disruption promotes amyloidgenic amyloid precursor protein catabolism

species. Aptamers are single stranded oligonucleotide molecules that can be selected to bind to specific target molecules, and have comparable affinity to monoclonal antibodies. Methods: We have attempted to develop single stranded DNA aptamers that bind specifically to trimeric Ab species using the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) method. Ab proteins from cadaveric human CSF were used as source materials. CSF samples were concentrated and subjected to size exclusion chromatography (SEC), yielding semi-purified fractions containing trimeric Ab species, which were coupled to antibody-coated magnetic beads and used to screen the aptamer library. Results: Initial screening for potential binders after the sixth round of SELEX was performed using aptamoprecipitation of Ab oligomers from cadaveric human CSF. Further rounds of SELEX and screening are currently underway. Conclusions: If obtained, these aptamers would be an important tool to investigate the specific roles of Ab trimers in AD. This finding would also show that it is possible to generate aptamers that bind specifically to distinct oligomeric Ab species.