A genetic screen in Drosophila uncovers a role for senseless-2 in surface glia in the peripheral nervous system to regulate CNS morphology
(2024) G3 (Bethesda, Md.), 14 (9), .
Lacin, H.a , Zhu, Y.b , DiPaola, J.T.b , Wilson, B.A.b , Zhu, Y.b , Skeath, J.B.b
a Division of Biological and Biomedical Systems, University of Missouri-Kansas City, 5009 Rockhill Road, Kansas City, MO 64110, United States
b Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St. Louis, MO 63110, United States
Abstract
Despite increasing in mass approximately 100-fold during larval life, the Drosophila CNS maintains its characteristic form. Dynamic interactions between the overlying basement membrane and underlying surface glia are known to regulate CNS structure in Drosophila, but the genes and pathways that establish and maintain CNS morphology during development remain poorly characterized. To identify genes that regulate CNS shape in Drosophila, we conducted an EMS-based, forward genetic screen of the second chromosome, uncovered 50 mutations that disrupt CNS structure, and mapped these alleles to 17 genes. Analysis of whole genome sequencing data wedded to genetic studies uncovered the affected gene for all but 1 mutation. Identified genes include well-characterized regulators of tissue shape, like LanB1, viking, and Collagen type IV alpha1, and previously characterized genes, such as Toll-2 and Rme-8, with no known role in regulating CNS structure. We also uncovered that papilin and C1GalTA likely act in the same pathway to regulate CNS structure and found that the fly homolog of a glucuronosyltransferase, B4GAT1/LARGE1, that regulates Dystroglycan function in mammals is required to maintain CNS shape in Drosophila. Finally, we show that the senseless-2 transcription factor is expressed and functions specifically in surface glia found on peripheral nerves but not in the CNS to govern CNS structure, identifying a gene that functionally subdivides a glial subtype along the peripheral-central axis. Future work on these genes should clarify the genetic mechanisms that ensure the homeostasis of CNS form during development. © The Author(s) 2024. Published by Oxford University Press on behalf of The Genetics Society of America.
Author Keywords
Drosophila; papilin; senseless-2; basement membrane; CNS; glia
Document Type: Article
Publication Stage: Final
Source: Scopus
TREM2 on microglia cell surface binds to and forms functional binary complexes with heparan sulfate modified with 6-O-sulfation and iduronic acid
(2024) Journal of Biological Chemistry, 300 (9), art. no. 107691, .
McMillan, I.O.a , Liang, L.b c , Su, G.d , Song, X.a , Drago, K.a , Yang, H.a , Alvarez, C.a , Sood, A.e , Gibson, J.b c , Woods, R.J.e , Wang, C.b c , Liu, J.f , Zhang, F.b c , Brett, T.J.g , Wang, L.a
a Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, Tampa, FL, United States
b Departments of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, United States
c Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, United States
d Glycan Therapeutics, Raleigh, NC, United States
e Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
f Division of Chemical Biology and Medicinal Chemistry, University of North Carolina at Chapel Hill, Eshelman School of Pharmacy, Chapel Hill, NC, United States
g Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, United States
Abstract
The triggering receptor expressed on myeloid cells-2 (TREM2), a pivotal innate immune receptor, orchestrates functions such as inflammatory responses, phagocytosis, cell survival, and neuroprotection. TREM2 variants R47H and R62H have been associated with Alzheimer’s disease, yet the underlying mechanisms remain elusive. Our previous research established that TREM2 binds to heparan sulfate (HS) and variants R47H and R62H exhibit reduced affinity for HS. Building upon this groundwork, our current study delves into the interplay between TREM2 and HS and its impact on microglial function. We confirm TREM2’s binding to cell surface HS and demonstrate that TREM2 interacts with HS, forming HS-TREM2 binary complexes on microglia cell surfaces. Employing various biochemical techniques, including surface plasmon resonance, low molecular weight HS microarray screening, and serial HS mutant cell surface binding assays, we demonstrate TREM2’s robust affinity for HS, and the effective binding requires a minimum HS size of approximately 10 saccharide units. Notably, TREM2 selectively binds specific HS structures, with 6-O-sulfation and, to a lesser extent, the iduronic acid residue playing crucial roles. N-sulfation and 2-O-sulfation are dispensable for this interaction. Furthermore, we reveal that 6-O-sulfation is essential for HS-TREM2 ternary complex formation on the microglial cell surface, and HS and its 6-O-sulfation are necessary for TREM2-mediated ApoE3 uptake in microglia. By delineating the interaction between HS and TREM2 on the microglial cell surface and demonstrating its role in facilitating TREM2-mediated ApoE uptake by microglia, our findings provide valuable insights that can inform targeted interventions for modulating microglial functions in Alzheimer’s disease. © 2024 The Authors
Author Keywords
binary complex; heparan sulfate; microglia; structure-function; TREM2
Document Type: Article
Publication Stage: Final
Source: Scopus
Differential components of bradykinesia in Parkinson’s disease revealed by deep brain stimulation
(2024) Journal of Neurophysiology, 132 (3), pp. 870-878.
Mazzoni, P.a b , Ushe, M.b , Younce, J.R.b , Norris, S.A.b , Hershey, T.b , Karimi, M.b , Tabbal, S.D.b , Perlmutter, J.S.b
a Division of Movement Disorders, Department of Neurology, Ohio State University, Columbus, OH, United States
b Division of Movement Disorders, Department of Neurology, Washington University in St. Louis, St. Louis, MO, United States
Abstract
Bradykinesia is a term describing several manifestations of movement disruption caused by Parkinson’s disease (PD), including movement slowing, amplitude reduction, and gradual decrease of speed and amplitude over multiple repetitions of the same movement. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves bradykinesia in patients with PD. We examined the effect of DBS on specific components of bradykinesia when applied at two locations within the STN, using signal processing techniques to identify the time course of amplitude and frequency of repeated hand pronation-supination movements performed by participants with and without PD. Stimulation at either location increased movement amplitude, increased frequency, and decreased variability, though not to the range observed in the control group. Amplitude and frequency showed decrement within trials, which was similar in PD and control groups and did not change with DBS. Decrement across trials, by contrast, differed between PD and control groups, and was reduced by stimulation. We conclude that DBS improves specific aspects of movement that are disrupted by PD, whereas it does not affect short-term decrement that could reflect muscular fatigue.NEW & NOTEWORTHY In this study, we examined different components of bradykinesia in patients with Parkinson’s disease (PD). We identified different components through signal processing techniques and their response to deep brain stimulation (DBS). We found that some components of bradykinesia respond to stimulation, whereas others do not. This knowledge advances our understanding of brain mechanisms that control movement speed and amplitude.
Author Keywords
DBS; kinematics; motor control; movement; wearable sensors
Document Type: Article
Publication Stage: Final
Source: Scopus
Hypertension and cerebral blood flow in the development of Alzheimer’s disease
(2024) Alzheimer’s and Dementia, .
Bachmann, D.a b , Saake, A.a , Studer, S.a , Buchmann, A.a , Rauen, K.a c d , Gruber, E.a , Michels, L.e , Nitsch, R.M.a f , Hock, C.a f , Gietl, A.a c , Treyer, V.a g , Weiner, M.W.h , Trojanowski, J.Q.i , Shaw, L.i , Beckett, L.j , Aisen, P.k , Petersen, R.l , Morris, J.C.m , Perrin, R.J.l , Toga, A.W.k , Jack, C.l , Green, R.C.n , Jagust, W.o , Saykin, A.J.p , for the Alzheimer’s Disease Neuroimaging Initiativeq
a Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
b Department of Health Sciences and Technology, ETH Zürich, Zurich, Switzerland
c Department of Geriatric Psychiatry, Psychiatric Hospital Zurich, Zurich, Switzerland
d Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
e Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich, Zurich, Switzerland
f Neurimmune, Zurich, Switzerland
g Department of Nuclear Medicine, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
h University of California, San Francisco, United States
i University of PennsylvaniaPA, United States
j University of California, Davis, United States
k University of Southern CaliforniaCA, United States
l Mayo Clinic, Rochester, MN, United States
m Washington University, St. Louis, United States
n Brigham and Women’s Hospital/Harvard Medical SchoolMA, United States
o University of California, Berkeley, United States
p Indiana University, Indiana, United States
Abstract
INTRODUCTION: We investigated the interactive associations between amyloid and hypertension on the entorhinal cortex (EC) tau and atrophy and the role of cerebral blood flow (CBF) as a shared mechanism by which amyloid and hypertension contribute to EC tau and regional white matter hyperintensities (WMHs). METHODS: We analyzed data from older adults without dementia participating in the Add-Tau study (NCT02958670, n = 138) or Alzheimer’s Disease Neuroimaging Initiative (ADNI) (n = 523) who had available amyloid-positron emission tomography (PET), tau-PET, fluid-attenuated inversion recovery (FLAIR), and T1-weighted magnetic resonance imaging (MRI). A subsample in both cohorts had available arterial spin labeling (ASL) MRI (Add-Tau: n = 78; ADNI: n = 89). RESULTS: The detrimental effects of hypertension on AD pathology and EC thickness were more pronounced in the Add-Tau cohort. Increased amyloid burden was associated with decreased occipital gray matter CBF in the ADNI cohort. In both cohorts, lower regional gray matter CBF was associated with higher EC tau and posterior WMH burden. DISCUSSION: Reduced cerebral perfusion may be one common mechanism through which hypertension and amyloid are related to increased EC tau and WMH volume. Highlights: Hypertension is associated with increased entorhinal cortex (EC) tau, particularly in the presence of amyloid. Decreased cortical cerebral blood flow (CBF) is associated with higher regional white matter hyperintensity volume. Increasing amyloid burden is associated with decreasing CBF in the occipital lobe. MTL CBF and amyloid are synergistically associated with EC tau. © 2024 The Author(s). Alzheimer’s & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer’s Association.
Author Keywords
Alzheimer’s disease; amyloid pathology; arterial spin labeling; cerebral perfusion; regional white matter hyperintensities; small vessel disease; tau pathology
Document Type: Article
Publication Stage: Article in Press
Source: Scopus
Missense and loss-of-function variants at GWAS loci in familial Alzheimer’s disease
(2024) Alzheimer’s and Dementia, .
Gunasekaran, T.I.a , Reyes-Dumeyer, D.a , Faber, K.M.b , Goate, A.c , Boeve, B.d , Cruchaga, C.e , Pericak-Vance, M.f , Haines, J.L.g , Rosenberg, R.h , Tsuang, D.i , Mejia, D.R.j k , Medrano, M.l , Lantigua, R.A.a m , Sweet, R.A.n , Bennett, D.A.o , Wilson, R.S.o , Alba, C.p , Dalgard, C.p , Foroud, T.b , Vardarajan, B.N.a , Mayeux, R.a
a Department of Neurology, Taub Institute for Research on Alzheimer’s Disease and the Aging Brain and the Gertrude H. Sergievsky Center, Columbia University, New York, NY, United States
b Department of Medical and Molecular Genetics, National Centralized Repository for Alzheimer’s Disease and Related Dementias (NCRAD), 410 W. 10th St., HS 4000. Indiana University School of Medicine, Indianapolis, IN, United States
c Department of Genetics & Genomic Sciences, Ronald M. Loeb Center for Alzheimer’s disease, Icahn School of Medicine at Mount Sinai, Icahn Bldg., One Gustave L. Levy Place, New York, NY, United States
d Department of Neurology, Mayo Clinic, Rochester, MN, United States
e Department of Psychiatry, Washington University in St. Louis, Rand Johnson Building, 600 S Euclid Ave., Wohl Hospital Building, St. Louis, MO, United States
f John P Hussman Institute for Human Genomics, Dr. John T Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, United States
g Department of Population & Quantitative Health Sciences and Cleveland Institute for Computational Biology. Case Western Reserve University, Cleveland, OH, United States
h Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, United States
i Department of Psychiatry and Behavioral Sciences, University of Washington, GRECC VA Puget Sound, 1660 South Columbian Way, Seattle, WA, United States
j Los Centros de Diagnóstico y Medicina Avanzada y de Conferencias Médicas y Telemedicina, CEDIMAT, Arturo Logroño, Plaza de la Salud, Dr. Juan Manuel Taveras Rodríguez, C. Pepillo Salcedo esq, Santo Domingo, Dominican Republic
k Universidad Pedro Henríquez Urena, Av. John F. Kennedy Km. 7-1/2 Santo Domingo 1423, Santo Domingo, Dominican Republic
l Pontíficia Universidad Católica Madre y Maestra (PUCMM), Autopista Duarte Km 1 1/2, Santiago de los Caballeros, Dominican Republic
m Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, and the New York Presbyterian Hospital, New York, NY, United States
n Departments of Psychiatry and Neurology, University of Pittsburgh, Pittsburgh, PA, United States
o Rush Alzheimer’s Disease Center, Rush University Medical Center, 1750, West Harrison St, Chicago, IL, United States
p Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
Abstract
BACKGROUND: Few rare variants have been identified in genetic loci from genome-wide association studies (GWAS) of Alzheimer’s disease (AD), limiting understanding of mechanisms, risk assessment, and genetic counseling. METHODS: Using genome sequencing data from 197 families in the National Institute on Aging Alzheimer’s Disease Family Based Study and 214 Caribbean Hispanic families, we searched for rare coding variants within known GWAS loci from the largest published study. RESULTS: Eighty-six rare missense or loss-of-function (LoF) variants completely segregated in 17.5% of families, but in 91 (22.1%) families Apolipoprotein E (APOE)-Ԑ4 was the only variant segregating. However, in 60.3% of families, APOE Ԑ4, missense, and LoF variants were not found within the GWAS loci. DISCUSSION: Although APOE Ԑ4and several rare variants were found to segregate in both family datasets, many families had no variant accounting for their disease. This suggests that familial AD may be the result of unidentified rare variants. Highlights: Rare coding variants from GWAS loci segregate in familial Alzheimer’s disease. Missense or loss of function variants were found segregating in nearly 7% of families. APOE-Ԑ4 was the only segregating variant in 29.7% in familial Alzheimer’s disease. In Hispanic and non-Hispanic families, different variants were found in segregating genes. No coding variants were found segregating in many Hispanic and non-Hispanic families. © 2024 The Author(s). Alzheimer’s & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer’s Association.
Author Keywords
familial Alzheimer’s disease; gene loci; genetic segregation; genome wide association studies; rare variants
Funding details
Rainwater Charitable FoundationRCF
Lewy Body Dementia AssociationLBDA
M.B. and Edna Zale Foundation
American Academy of NeurologyAAN
American Brain FoundationABF
AG072547, AG074865, AG062677, AG070864
National Institutes of HealthNIHR01 AG067501, R56AG051876, U01AG066752, RF1AG015473
National Institute on AgingNIAU24AG056270, U24AG026395, U24AG021886
Document Type: Article
Publication Stage: Article in Press
Source: Scopus
Engineered T cell therapy for central nervous system injury
(2024) Nature, .
Gao, W.a b , Kim, M.W.a b c d , Dykstra, T.a b , Du, S.a b c , Boskovic, P.a b , Lichti, C.F.b e , Ruiz-Cardozo, M.A.f , Gu, X.a b , Weizman Shapira, T.g , Rustenhoven, J.a b , Molina, C.f , Smirnov, I.a b , Merbl, Y.g , Ray, W.Z.f , Kipnis, J.a b c d
a Center for Brain Immunology and Glia (BIG), Washington University in St. Louis, School of Medicine, St. Louis, MO, United States
b Department of Pathology and Immunology, Washington University in St. Louis, School of Medicine, St. Louis, MO, United States
c Immunology Program, School of Medicine, Washington University in St. Louis, School of Medicine, St. Louis, MO, United States
d Medical Scientist Training Program, School of Medicine, Washington University in St. Louis, School of Medicine, St. Louis, MO, United States
e Bursky Center for Human Immunology and Immunotherapy Programs, Washington University in St. Louis, School of Medicine, St. Louis, MO, United States
f Department of Neurological Surgery, Washington University in St. Louis, School of Medicine, St. Louis, MO, United States
g Systems Immunology Department, The Weizmann Institute of Science, Rehovot, Israel
Abstract
Traumatic injuries to the central nervous system (CNS) afflict millions of individuals worldwide1, yet an effective treatment remains elusive. Following such injuries, the site is populated by a multitude of peripheral immune cells, including T cells, but a comprehensive understanding of the roles and antigen specificity of these endogenous T cells at the injury site has been lacking. This gap has impeded the development of immune-mediated cellular therapies for CNS injuries. Here, using single-cell RNA sequencing, we demonstrated the clonal expansion of mouse and human spinal cord injury-associated T cells and identified that CD4+ T cell clones in mice exhibit antigen specificity towards self-peptides of myelin and neuronal proteins. Leveraging mRNA-based T cell receptor (TCR) reconstitution, a strategy aimed to minimize potential adverse effects from prolonged activation of self-reactive T cells, we generated engineered transiently autoimmune T cells. These cells demonstrated notable neuroprotective efficacy in CNS injury models, in part by modulating myeloid cells via IFNγ. Our findings elucidate mechanistic insight underlying the neuroprotective function of injury-responsive T cells and pave the way for the future development of T cell therapies for CNS injuries. © The Author(s), under exclusive licence to Springer Nature Limited 2024.
Document Type: Article
Publication Stage: Article in Press
Source: Scopus
Frontostriatal salience network expansion in individuals in depression
(2024) Nature, .
Lynch, C.J.a , Elbau, I.G.a , Ng, T.a , Ayaz, A.a , Zhu, S.a , Wolk, D.a , Manfredi, N.a , Johnson, M.a , Chang, M.a , Chou, J.a , Summerville, I.a , Ho, C.a , Lueckel, M.b c , Bukhari, H.a , Buchanan, D.d , Victoria, L.W.a , Solomonov, N.a , Goldwaser, E.a , Moia, S.e f g , Caballero-Gaudes, C.g , Downar, J.h , Vila-Rodriguez, F.i , Daskalakis, Z.J.j , Blumberger, D.M.h k l , Kay, K.m , Aloysi, A.n , Gordon, E.M.o , Bhati, M.T.d , Williams, N.d , Power, J.D.a , Zebley, B.a , Grosenick, L.a , Gunning, F.M.a , Liston, C.a
a Department of Psychiatry, Weill Cornell Medicine, New York, NY, United States
b Leibniz Institute for Resilience Research, Mainz, Germany
c Neuroimaging Center (NIC), Focus Program Translational Neurosciences (FTN), Johannes Gutenberg University Medical Center, Mainz, Germany
d Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States
e Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
f Department of Radiology and Medical Informatics, Faculty of Medicine, University of Geneva, Geneva, Switzerland
g Basque Center on Cognition, Brain and Language, Donostia, Spain
h Department of Psychiatry and Institute of Medical Science, University of Toronto, Toronto, ON, Canada
i Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
j Department of Psychiatry, University of California, San Diego, CA, United States
k Temerty Centre for Therapeutic Brain Intervention, Toronto, ON, Canada
l Centre for Addiction and Mental Health, Toronto, ON, Canada
m Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States
n Icahn School of Medicine at Mount Sinai, New York, NY, United States
o Department of Radiology, Washington University School of Medicine, St. Louis, MO, United States
Abstract
Decades of neuroimaging studies have shown modest differences in brain structure and connectivity in depression, hindering mechanistic insights or the identification of risk factors for disease onset1. Furthermore, whereas depression is episodic, few longitudinal neuroimaging studies exist, limiting understanding of mechanisms that drive mood-state transitions. The emerging field of precision functional mapping has used densely sampled longitudinal neuroimaging data to show behaviourally meaningful differences in brain network topography and connectivity between and in healthy individuals2–4, but this approach has not been applied in depression. Here, using precision functional mapping and several samples of deeply sampled individuals, we found that the frontostriatal salience network is expanded nearly twofold in the cortex of most individuals with depression. This effect was replicable in several samples and caused primarily by network border shifts, with three distinct modes of encroachment occurring in different individuals. Salience network expansion was stable over time, unaffected by mood state and detectable in children before the onset of depression later in adolescence. Longitudinal analyses of individuals scanned up to 62 times over 1.5 years identified connectivity changes in frontostriatal circuits that tracked fluctuations in specific symptoms and predicted future anhedonia symptoms. Together, these findings identify a trait-like brain network topology that may confer risk for depression and mood-state-dependent connectivity changes in frontostriatal circuits that predict the emergence and remission of depressive symptoms over time. © The Author(s) 2024.
Funding details
Wellcome Leap
Hope for Depression Research FoundationHDRF
Deutsche ForschungsgemeinschaftDFG
National Institute of Mental HealthNIMHF32MH120989, K23 MH123864
California Department of Fish and GameDFGCRC 1193
Document Type: Article
Publication Stage: Article in Press
Source: Scopus
Alzheimer’s disease genetic risk and changes in brain atrophy and white matter hyperintensities in cognitively unimpaired adults
(2024) Brain Communications, 6 (5), art. no. fcae276, .
Soldan, A.a , Wang, J.b , Pettigrew, C.a , Davatzikos, C.c , Erus, G.c , Hohman, T.J.d , Dumitrescu, L.d , Bilgel, M.e , Resnick, S.M.e , Rivera-Rivera, L.A.f , Langhough, R.f , Johnson, S.C.f , Benzinger, T.g , Morris, J.C.g , Laws, S.M.h , Fripp, J.i , Masters, C.L.j , Albert, M.S.a
a Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
b Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, United States
c Centre for Biomedical Image Computing and Analytics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
d Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37212, United States
e Laboratory of Behavioral Neuroscience, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, United States
f Wisconsin Alzheimer’s Disease Research Center, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI 53726, United States
g Knight Alzheimer Disease Research Center, Washington University, School of Medicine, St. Louis, MO 63110, United States
h Centre for Precision Health, Edith Cowan University, Joondalup, WA 6027, Australia
i Australian E-Health Research Centre, CSIRO Health and Biosecurity, Herston, QLD 4029, Australia
j The Florey Institute, University of Melbourne, Parkville, VIC 3052, Australia
Abstract
Reduced brain volumes and more prominent white matter hyperintensities on MRI scans are commonly observed among older adults without cognitive impairment. However, it remains unclear whether rates of change in these measures among cognitively normal adults differ as a function of genetic risk for late-onset Alzheimer’s disease, including APOE- ε4, APOE-ε2 and Alzheimer’s disease polygenic risk scores (AD-PRS), and whether these relationships are influenced by other variables. This longitudinal study examined the trajectories of regional brain volumes and white matter hyperintensities in relationship to APOE genotypes (N = 1541) and AD-PRS (N = 1093) in a harmonized dataset of middle-aged and older individuals with normal cognition at baseline (mean baseline age = 66 years, SD = 9.6) and an average of 5.3 years of MRI follow-up (max = 24 years). Atrophy on volumetric MRI scans was quantified in three ways: (i) a composite score of regions vulnerable to Alzheimer’s disease (SPARE-AD); (ii) hippocampal volume; and (iii) a composite score of regions indexing advanced non-Alzheimer’s disease-related brain aging (SPARE-BA). Global white matter hyperintensity volumes were derived from fluid attenuated inversion recovery (FLAIR) MRI. Using linear mixed effects models, there was an APOE-ε4 gene-dose effect on atrophy in the SPARE-AD composite and hippocampus, with greatest atrophy among ε4/ε4 carriers, followed by ε4 heterozygouts, and lowest among ε3 homozygouts and ε2/ε2 and ε2/ε3 carriers, who did not differ from one another. The negative associations of APOE-ε4 with atrophy were reduced among those with higher education (P < 0.04) and younger baseline ages (P < 0.03). Higher AD-PRS were also associated with greater atrophy in SPARE-AD (P = 0.035) and the hippocampus (P = 0.014), independent of APOE-ε4 status. APOE-ε2 status (ε2/ε2 and ε2/ε3 combined) was not related to baseline levels or atrophy in SPARE-AD, SPARE-BA or the hippocampus, but was related to greater increases in white matter hyperintensities (P = 0.014). Additionally, there was an APOE-ε4 × AD-PRS interaction in relation to white matter hyperintensities (P = 0.038), with greater increases in white matter hyperintensities among APOE-ε4 carriers with higher AD-PRS. APOE and AD-PRS associations with MRI measures did not differ by sex. These results suggest that APOE-ε4 and AD-PRS independently and additively influence longitudinal declines in brain volumes sensitive to Alzheimer’s disease and synergistically increase white matter hyperintensity accumulation among cognitively normal individuals. Conversely, APOE-ε2 primarily influences white matter hyperintensity accumulation, not brain atrophy. Results are consistent with the view that genetic factors for Alzheimer’s disease influence atrophy in a regionally specific manner, likely reflecting preclinical neurodegeneration, and that Alzheimer’s disease risk genes contribute to white matter hyperintensity formation. © 2024 The Author(s).
Author Keywords
Alzheimer’s disease (AD); APOE; magnetic resonance imaging (MRI); polygenic risk score (PRS); white matter hyperintensities
Funding details
Commonwealth Scientific and Industrial Research OrganisationCSIRO
National Institutes of HealthNIHRF1-AG027161, RF1-AG059869, U19-AG033655, P01-AG026276
National Institute on AgingNIAP30-AG062715, P01-AG003991, U19-AG024904, P30-AG066444, P20-AG068082, P30-AG066507, U19-AG032438
Document Type: Article
Publication Stage: Final
Source: Scopus