Faculty Bibliography
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Alzheimer's & dementia : the journal of the Alzheimer's Association. 2025:21(6).DOI: 10.1002/alz.70158
The history of Down syndrome-associated Alzheimer's disease; past, present, and future [Historical Article]
The landscape of Down syndrome-associated Alzheimer's disease (DSAD) research reflects decades of scientific endeavor and collaborative effort, charting a remarkable journey from initial observations to the elucidation of complex genetic and molecular mechanisms. This perspective article chronicles key milestones and breakthroughs, paying homage to the pioneering scientists and advancements that have shaped the field. A thorough review of historical and contemporary literature offers a comprehensive narrative, highlighting the evolution of knowledge surrounding DSAD, from early recognition to the characterization of clinical presentation and natural history. The unique challenges and ethical considerations associated with DSAD populations are also examined, underscoring the importance of tailoring research and clinical approaches. By reflecting on the field's trajectory, this work celebrates past achievements while emphasizing the critical need for sustained research efforts. As part of a special issue, this article provides a foundation for appreciating the challenges and opportunities that lie ahead in advancing DSAD understanding and care. HIGHLIGHTS: This article provides a comprehensive overview of Down syndrome-associated Alzheimer's disease (DSAD) history, from early descriptions to its recognition as a genetic form of AD. It reflects on historical challenges faced by individuals with intellectual disabilities in achieving inclusion in scientific research. This historical perspective highlights the critical contributions of individuals with DS in advancing understanding of AD natural history. It explores pivotal milestones and efforts that have driven progress in DSAD research. Finally, it provides context to understand challenges and opportunities in DSAD research and its future directions.
PMCID:12138279
PMID: 40469048
ISSN: 1552-5279
CID: 5862592
SARS-CoV-2 infection of human cortical cells is influenced by the interaction between aneuploidy and biological sex: insights from a Down syndrome in vitro model
Individuals with Down Syndrome (DS) represent one of the most susceptible populations for developing severe COVID-19, and a unique human genetic condition for investigating molecular mechanisms underlying susceptibility of neurologically vulnerable individuals to SARS-CoV-2 infection. Human Chromosome-21 (HSA21) triplication in DS causes global transcriptional deregulation, affecting multiple genes that may directly (e.g., TMPRSS2) or indirectly influence the SARS-CoV-2 entry into central nervous system (CNS) cells. The anti-viral immune response may also be altered in cells with trisomy-21 (T21) due to triplication of genes encoding for several interferon receptor subunits and interferon-stimulated genes (ISGs). Here, we demonstrate that human cells derived from fetal cortical specimens and maintained in primary cultures are susceptible to infection with a molecular clone of vesicular stomatitis virus engineered to express the Spike protein of SARS-CoV-2 (VSV-eGFP-SARS-CoV-2) and to authentic SARS-CoV-2. The level of SARS-CoV-2 infectivity in cultures originated from different cortical specimens varied, seemingly depending on ploidy and chromosomal sex of the cells. We confirmed the presence of ACE2 and TMPRSS2 in cultures and found that XY T21 group had the highest TMPRSS2 mRNA levels, which was associated with increased infectivity in XY-compared to XX T21 cultures. The XX T21 cultures exhibited elevated expression of several ISGs (MX1, STAT1, and STAT2) which was associated with lower infectivity. The comparisons of postmortem aged brain specimens revealed reduced ACE2, TMPRSS2, but elevated STAT2 protein levels in individuals with DS and Alzheimer's disease (DS-AD) compared to control and Alzheimer's disease (AD) group. Collectively, these results suggest multifactorial regulation of SARS-CoV-2 infectivity in cortical cells that involves ploidy, chromosomal sex, and the expression of genes implicated in regulation of virus entry and anti-viral response as contributing factors.
PMCID:12125050
PMID: 40445428
ISSN: 1432-0533
CID: 5854522
CT, I-123-Ioflupane SPECT, and Integrated FDG PET-MRI of a Patient With Fahr Disease
Fahr disease is a rare neurodegenerative syndrome characterized by abnormal symmetric calcium deposition in the white matter, cerebral cortex, deep gray, and cerebellar nuclei. The characteristic CT pattern is well known, but descriptions of molecular imaging in Fahr disease remain sparse. We present the characteristic imaging patterns of Fahr disease by CT, I-123-Ioflupane SPECT, and integrated FDG PET/MRI in a single patient.
PMID: 40392166
ISSN: 1536-0229
CID: 5852972
The interactome of tau phosphorylated at T217 in Alzheimer's disease human brain tissue
Hyperphosphorylated tau (pTau) in Alzheimer's disease (AD) brain tissue is a complex mix of multiple tau species that are variably phosphorylated. The emerging studies suggest that phosphorylation of specific residues may alter the role of tau. The role of specific pTau species can be explored through protein interactome studies. The aim of this study was to analyse the interactome of tau phosphorylated at T217 (pT217), which biomarker studies suggest is one of the earliest accumulating tau species in AD. pT217 interactors were identified in fresh-frozen human brain tissue from 10 cases of advanced AD using affinity purification-mass spectrometry. The cases included a balanced cohort of APOE ε3/ε3 and ε4/ε4 genotypes (n = 5 each) to explore how apolipoprotein E altered phosphorylated tau interactions. The results were compared to our previous interactome dataset that profiled the interactors of PHF1-enriched tau to determine if individual pTau species have different interactomes. 23 proteins were identified as bona fide pT217 interactors, including known pTau interactor SQSTM1. pT217 enriched tau was phosphorylated at fewer residues compared to PHF1-enriched tau, suggesting an earlier stage of pathology development. Notable pT217 interactors included five subunits of the CTLH E3 ubiquitin ligase (WDR26, ARMC8, GID8, RANBP9, MAEA), which has not previously been linked to AD. In APOE ε3/ε3 cases pT217 significantly interacted with 46 proteins compared to 28 in APOE ε4/ε4 cases, but these proteins were significantly overlapped. CTLH E3 ubiquitin ligase subunits significantly interacted with phosphorylated tau in both APOE genotypes. pT217 interactions with SQSTM1, WDR26 and RANBP9 were validated using co-immunoprecipitation and immunofluorescent microscopy of post-mortem human brain tissue, which showed colocalisation of both protein interactors with tau pathology. Our results report the interactome of pT217 in human Alzheimer's disease brain tissue for the first time and highlight the CTLH E3 ubiquitin ligase complex as a significant novel interactor of pT217 tau.
PMCID:12049313
PMID: 40317322
ISSN: 1432-0533
CID: 5834712
Nerve growth factor precursor alterations in neuron-derived extracellular vesicles from individuals with Down syndrome along the Alzheimer's disease continuum
BACKGROUND:In Down syndrome (DS) and Alzheimer's disease (AD), nerve growth factor precursor protein (proNGF) accumulates in the brain. However, its non-invasive detection using neuron-derived extracellular vesicles (NDEVs) from plasma remains unexplored. METHODS:We included 139 adults with DS (45 asymptomatic [aDS], 94 symptomatic for AD [sDS]) and 37 healthy controls. NDEVs were isolated from plasma. ProNGF and tetraspanin (CD81) were quantified by enzyme-linked immunosorbent assay. We assessed proNGF/CD81 changes with age, along the AD continuum (aDS and sDS), and associations with cerebrospinal fluid (CSF), plasma biomarkers, episodic memory, and basal forebrain volume. RESULTS:In DS, proNGF/CD81 levels increased with age and were higher in NDEVs from asymptomatic and symptomatic individuals compared to controls, with the highest levels in the symptomatic group. ProNGF correlated with CSF phosphorylated tau (p-tau)181, plasma p-tau217, neurofilament light chain, and episodic memory. DISCUSSION/CONCLUSIONS:ProNGF/CD81 levels in NDEVs increase along the AD continuum in DS and parallel tau pathology, indicating the potential as a promising biomarker for monitoring disease progression in plasma. HIGHLIGHTS/CONCLUSIONS:Nerve growth factor precursor protein (ProNGF)/tetraspanin (CD81) ratio increased in the third decade of life, 20 years before Alzheimer's disease (AD) symptom onset in Down syndrome (DS). proNGF/CD81 concentrations were significantly higher in individuals with DS compared to controls and were notably elevated in individuals with DS and symptomatic AD compared to asymptomatic AD. proNGF/CD81 concentrations were associated with tau pathology and neuronal injury.
PMCID:12010274
PMID: 40257051
ISSN: 1552-5279
CID: 5829912
Spatial proteomic differences in chronic traumatic encephalopathy, Alzheimer's disease, and primary age-related tauopathy hippocampi
INTRODUCTION/BACKGROUND:Alzheimer's disease (AD), primary age-related tauopathy (PART), and chronic traumatic encephalopathy (CTE) all feature hyperphosphorylated tau (p-tau)-immunoreactive neurofibrillary degeneration, but differ in neuroanatomical distribution and progression of neurofibrillary degeneration and amyloid beta (Aβ) deposition. METHODS:We used Nanostring GeoMx Digital Spatial Profiling to compare the expression of 70 proteins in neurofibrillary tangle (NFT)-bearing and non-NFT-bearing neurons in hippocampal CA1, CA2, and CA4 subregions and entorhinal cortex of cases with autopsy-confirmed AD (n = 8), PART (n = 7), and CTE (n = 5). RESULTS:There were numerous subregion-specific differences related to Aβ processing, autophagy/proteostasis, inflammation, gliosis, oxidative stress, neuronal/synaptic integrity, and p-tau epitopes among these different disorders. DISCUSSION/CONCLUSIONS:These results suggest that there are subregion-specific proteomic differences among the neurons of these disorders, which appear to be influenced to a large degree by the presence of hippocampal Aβ. These proteomic differences may play a role in the differing hippocampal p-tau distribution and pathogenesis of these disorders. HIGHLIGHTS/CONCLUSIONS:Alzheimer's disease neuropathologic change (ADNC), possible primary age-related tauopathy (PART), definite PART, and chronic traumatic encephalopathy (CTE) can be differentiated based on the proteomic composition of their neurofibrillary tangle (NFT)- and non-NFT-bearing neurons. The proteome of these NFT- and non-NFT-bearing neurons is largely correlated with the presence or absence of amyloid beta (Aβ). Neurons in CTE and definite PART (Aβ-independent pathologies) share numerous proteomic similarities that distinguish them from ADNC and possible PART (Aβ-positive pathologies).
PMCID:11848160
PMID: 39737785
ISSN: 1552-5279
CID: 5800392
Comparison of the amyloid plaque proteome in Down syndrome, early-onset Alzheimer's disease, and late-onset Alzheimer's disease
Down syndrome (DS) is strongly associated with Alzheimer's disease (AD) due to APP overexpression, exhibiting Amyloid-β (Aβ) and Tau pathology similar to early-onset (EOAD) and late-onset AD (LOAD). We evaluated the Aβ plaque proteome of DS, EOAD, and LOAD using unbiased localized proteomics on post-mortem paraffin-embedded tissues from four cohorts (n = 20/group): DS (59.8 ± 4.99 y/o), EOAD (63 ± 4.07 y/o), LOAD (82.1 ± 6.37 y/o), and controls (66.4 ± 13.04). We identified differentially abundant proteins when comparing Aβ plaques and neighboring non-plaque tissue (FDR < 5%, fold-change > 1.5) in DS (n = 132), EOAD (n = 192), and LOAD (n = 128), with 43 plaque-associated proteins shared across all groups. Positive correlations were observed between plaque-associated proteins in DS and EOAD (R2 = .77), DS and LOAD (R2 = .73), and EOAD and LOAD (R2 = .67). Top gene ontology biological processes (GOBP) included lysosomal transport (p = 1.29 × 10-5) for DS, immune system regulation (p = 4.33 × 10-5) for EOAD, and lysosome organization (p = 0.029) for LOAD. Protein networks revealed a plaque-associated protein signature involving APP metabolism, immune response, and lysosomal functions. In DS, EOAD, and LOAD non-plaque vs. control tissue, we identified 263, 269, and 301 differentially abundant proteins, with 65 altered proteins shared across all cohorts. Non-plaque proteins in DS showed modest correlations with EOAD (R2 = .59) and LOAD (R2 = .33) compared to the correlation between EOAD and LOAD (R2 = .79). Top GOBP term for all groups was chromatin remodeling (p < 0.001), with additional terms for DS including extracellular matrix, and protein-DNA complexes and gene expression regulation for EOAD and LOAD. Our study reveals key functional characteristics of the amyloid plaque proteome in DS, compared to EOAD and LOAD, highlighting shared pathways in endo/lysosomal functions and immune responses. The non-plaque proteome revealed distinct alterations in ECM and chromatin structure, underscoring unique differences between DS and AD subtypes. Our findings enhance our understanding of AD pathogenesis and identify potential biomarkers and therapeutic targets.
PMID: 39825890
ISSN: 1432-0533
CID: 5777842
Choroid plexus aging: structural and vascular insights from the HCP-aging dataset
BACKGROUND:The choroid plexus (ChP), a highly vascularized structure within the ventricles, is essential for cerebrospinal fluid (CSF) production and metabolic waste clearance, crucial for neurofluid homeostasis and cognitive function. ChP enlargement is seen in normal aging and neurodegenerative diseases like Alzheimer's disease (AD). Despite its key role of in the blood-CSF barrier (BCSFB), detailed studies on age-related changes in its perfusion and microstructure remain limited. METHODS:We analyzed data from 641 healthy individuals aged between 36 and 90, using the Human Connectome Project Aging (HCP-A) dataset. Volumetric, perfusion, and diffusion metrics of the ChP were derived from structural MRI, arterial spin labeling (ASL), and diffusion-weighted imaging (DWI), respectively. Partial correlations were used to explore age-related ChP changes, and independent t-tests to examine sex differences across age decades. One-way ANOVA was employed to compare perfusion characteristics among ChP, gray matter (GM), and white matter (WM). Relationships between volume, perfusion, and diffusion were investigated, adjusting for age and sex. Additionally, the distribution of cyst-like structures within the ChP and their diffusion/perfusion MRI characteristics were analyzed across different age groups. RESULTS: = 0.16, P < 0.001). Perfusion characteristics showed significant differences between the ChP, GM, and WM (P < 0.001). Both the ChP and GM exhibited age-related declines in CBF, with a more pronounced decline in the ChP. A negative correlation was observed between the age-related increase in ChP volume and the decrease in CBF, suggesting compensatory dystrophic hyperplasia in response to perfusion decline. Cyst-like structures in ChP, characterized by lower MD and reduced CBF, were found to be more prevalent in older individuals. CONCLUSIONS:Our findings provide a detailed quantitative assessment of age-related changes in ChP perfusion and diffusion, which may affect CSF production and circulation, potentially leading to waste solute accumulation and cognitive impairment. GRANT SUPPORT/UNASSIGNED:This work was supported in part by the NIH U01AG052564, P30AG066512, P01AG060882, RF1 NS110041, R01 NS108491, U24 NS135568.
PMCID:11619641
PMID: 39639335
ISSN: 2045-8118
CID: 5763822
X-chromosome-wide association study for Alzheimer's disease
Due to methodological reasons, the X-chromosome has not been featured in the major genome-wide association studies on Alzheimer's Disease (AD). To address this and better characterize the genetic landscape of AD, we performed an in-depth X-Chromosome-Wide Association Study (XWAS) in 115,841 AD cases or AD proxy cases, including 52,214 clinically-diagnosed AD cases, and 613,671 controls. We considered three approaches to account for the different X-chromosome inactivation (XCI) states in females, i.e. random XCI, skewed XCI, and escape XCI. We did not detect any genome-wide significant signals (P ≤ 5 × 10-
PMID: 39633006
ISSN: 1476-5578
CID: 5804132
Vascular Aging in the Choroid Plexus: A 7T Ultrasmall Superparamagnetic Iron Oxide (USPIO)-MRI Study
BACKGROUND:The choroid plexus (ChP), a densely vascularized structure, has drawn increasing attention for its involvement in brain homeostasis and waste clearance. While the volumetric changes have been explored in many imaging studies, few studies have investigated the vascular degeneration associated with aging in the ChP. PURPOSE/OBJECTIVE:To investigate the sub-structural characteristics of the ChP, particularly the vascular compartment using high-resolution 7T imaging enhanced with Ferumoxytol, an ultrasmall super-paramagnetic iron oxide, which greatly increase the susceptibility contrast for vessels. STUDY TYPE/METHODS:Prospective. SUBJECTS/METHODS:Forty-nine subjects without neurological disorders (age: 21-80 years; 42 ± 17 years; 20 females). FIELD STRENGTH/SEQUENCE/UNASSIGNED:7-T with 2D and 3D T2* GRE, 3D MPRAGE T1, 2D TSE T2, and 2D FLAIR. ASSESSMENT/RESULTS:ratio) and susceptibility change (Δχ) induced by Ferumoxytol were analyzed on 3D GRE-derived susceptibility-weighted imaging and quantitative susceptibility mapping, respectively. STATISTICAL TESTS/METHODS:Independent t-test, Mann-Whitney U test, and Chi-square test were utilized for group comparisons. The relationship between age and ChP's vascular alterations was examined using Pearson's correlation. Intra-class coefficient was calculated for inter-observer agreement. A P value <0.05 was considered statistically significant. RESULTS:2D GRE images demonstrated superior contrast and accurate delineation of ChP substructures (ICC = 0.86). Older subjects exhibited a significantly smaller vascular density (16.5 ± 4.34%) and lower Δχ (22.10 ± 12.82 ppb) compared to younger subjects (24.85 ± 6.84% and 34.64 ± 12.69 ppb). Vascular density and mean Δχ within the ChP negatively correlated with age (r = -0.48, and r = -0.45). DATA CONCLUSION/CONCLUSIONS:Ferumoxytol-enhanced 7T images can demonstrate ChP alterations in elderly with decreased vascular density and expansion of nonvascular compartment. EVIDENCE LEVEL/METHODS:1 TECHNICAL EFFICACY: Stage 2.
PMID: 38587279
ISSN: 1522-2586
CID: 5646032
