Neurosciences Commons^™

The Relationship Between Dietary Sodium Intake And Cognitive Function: A Narrative Review, Samantha L. Gardener, M. Fu, L. Morini, T. Schwartzkopff, G. Savage, R. N. Martins, S. R. Rainey-Smith

Research outputs 2022 to 2026

Purpose of Review: This narrative review provides discussion on current evidence regarding the relationship between sodium intake and cognitive function in animal and human studies, as well as potential mechanisms underlying this relationship. Recent Findings: Recent evidence suggests high sodium intake is associated with development of cognitive impairment and neural dysfunction. Additionally, studies have proposed that high sodium intake is associated with increased aggregation of Aβ-amyloid and that hypertension (for which high sodium intake is a risk factor) modulates the relationship between Aβ-amyloid and development of cognitive impairment and Alzheimer’s disease. However, while animal studies demonstrate a consistent relationship between …

Gut Microbiome Changes In Preclinical Alzheimer’S Disease, D. M. Sithara Dissanayaka, Stephanie R. Rainey-Smith, Hamid R. Sohrabi, Thilini N. Jayasinghe, Vincent Ho, Vijay Jayasena, Kevin Taddei, Colin L. Masters, Ralph N. Martins, W. M.A.D.Binosha Fernando

Research outputs 2022 to 2026

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that develops many years before clinical symptoms appear. The biological changes involved in the earliest stages remain poorly understood, particularly during the preclinical stage. Our previous work has identified gradual gut microbial and metabolic changes during this stage, suggesting these may represent early biological shifts that precede disease progression. Recent studies suggest that the gut microbiome may contribute to early AD processes through its effects on immune regulation, metabolism, and gut–brain communication. Changes in gut microbial composition, including reduced levels of short-chain fatty acid (SCFA)-producing bacteria, such as Faecalibacterium, Roseburia, and Eubacterium, …

Challenge-Based Ex Vivo Immune Profiling Reveals Stimulus-Dependent Peripheral Immune Reprogramming In Alzheimer's Disease, C. A. Naranjo-Galvis, Jovanny Zabaleta, Ney Alliey Rodriguez, Luisa Matilde Salamanca-Duque

School of Medicine Publications

Altered immune function is increasingly recognized as a contributor to Alzheimer's disease (AD); however, it remains unclear whether peripheral immune alterations reflect constitutive inflammation or stimulus-dependent changes in immune responsiveness. Addressing this distinction is critical for understanding immune dysregulation in neurodegenerative diseases. In this study, we applied a challenge-based ex vivo immune profiling approach to characterize functional immune responsiveness in patients with AD and in cognitively healthy older adults. Peripheral blood mononuclear cells were exposed to defined innate, antigenic, and mitogenic stimuli, and cytokine and β-amyloid (Aβ) responses were quantified in culture supernatants. Diagnosis-by-stimulus interaction effects were assessed using generalized …

Neuroprotective Effects Of Sorghum Polyphenol In Alzheimer’S Disease: In Vitro And In Silico Analyses, Rasheed A. Abdulraheem, Ralph N. Martins, Rajapandiyan Krishnamoorthy, Mohammad A. Alshuniaber, Prashant Bharadwaj, Zhaoyu Li, Ranil Coorey, Vijay Jayasena, Stuart K. Johnson, W. M.A.D.Binosha Fernando

Research outputs 2022 to 2026

Background/Objective: Accumulation of amyloid-beta (Aβ) senile plaques in the human brain is a major hallmark of Alzheimer’s disease (AD), which manifests as progressive decline in memory and cognitive functions and currently lacks effective disease-modifying therapies. Emerging evidence demonstrates that polyphenol-rich plant foods are potential complementary therapies for AD. Methods: In this study, we investigated crude polyphenol extracts (CPEs) and purified polyphenol extracts (PPEs) from three sorghum genotypes for their ability to inhibit Aβ42-induced toxicity in MC-65 cells. Thioflavin T fluorescence, cell viability, mitochondrial function, oxidative stress assays, and Western blotting, along with RNA sequencing and computational analyses, were used to …

The Poly-Arginine Peptide R18d Inhibits Amyloid-Beta (Aβ) Aggregation And Aβ-Induced Cytotoxicity, Reduces Intracellular Tau Aggregation, And Exhibits Oral Bioavailability, Vaishali Bagda, Zainab H. Farooz, Neville W. Knuckey, Samantha M. South, Stuart K. Gribble, Maitri Tomar, Prashant Bharadwaj, Ajish Ariyath, Kevin Taddei, Ralph N. Martins, Bruno P. Meloni

Research outputs 2022 to 2026

Background/Objectives: Effective disease-modifying therapies targeting pathogenic proteins associated with Alzheimer’s disease (AD) remain limited. This study investigated the therapeutic potential of the neuroprotective, cationic arginine-rich peptide R18D to mitigate the pathogenic effects of amyloid-beta (Aβ) and tau associated with AD.

Methods: R18D was examined for its ability to inhibit Aβ aggregation in a cell-free assay, attenuate Aβ-induced cytotoxicity in MC65 cells, and suppress intracellular tau aggregation in two neural cell models. Intracellular tau aggregation was quantified using a homogeneous time-resolved fluorescence assay. Additionally, a pilot pharmacokinetic study of R18D was conducted in mice following oral gavage administration.

Results: In the …

Higher Sodium Intake Is Associated With Episodic Memory Decline In Cognitively Unimpaired Older Males: A 6-Year Longitudinal Study, Francisca Chuwa, Stephanie R. Rainey-Smith, Hilal Salim Said Al Shamsi, Hamid Sohrabi, Kevin Taddei, Colin L. Masters, Ralph N. Martins, Samantha L. Gardener

Research outputs 2022 to 2026

Recent evidence has suggested an association between high sodium intake and development of cognitive impairment. However, while animal studies demonstrate consistent relationships between sodium intake and cognitive impairment, this relationship remains less clear in humans. Our aim was to investigate the relationship between self-reported baseline sodium intake and cognitive decline over 72 months. Cognitively unimpaired participants (n = 1208) from the Australian Imaging, Biomarkers and Lifestyle study were included (70.87 years of age; 41 % male). Participants completed a food frequency questionnaire to quantify sodium intake and underwent comprehensive neuropsychological assessment at baseline and four additional timepoints, 18 months apart. …

A High-Throughput Assay For Monitoring And Quantifying Amyloid-Β Accumulation And Clearance In Alzheimer's Disease Cell Models, Ajish Ariyath, Fraulein Denise Arigo, Anna Fyfe, W. M.A.D.Binosha Fernando, Ralph Martins, Prashant Bharadwaj

Research outputs 2022 to 2026

Amyloidogenic proteins, such as amyloid-β (Aβ), self-assemble into cross-β fibrils whose accumulation is central to Alzheimer's disease (AD). Measuring Aβ aggregation and clearance in living cells remains challenging using current cell-based assays, which are often low-throughput or not suited for real-time monitoring. This study aimed to (1) develop a robust, quantitative, and scalable fluorescence-based assay using Amytracker to monitor Aβ accumulation and clearance in an Aβ-producing neuronal cell model, and (2) validate its utility for mechanistic studies and therapeutic screening. We established a plate-based fluorescence assay using Amytracker in MC65 neuronal AD model expressing the Amyloid precursor protein C-terminal fragment …

Circulating Sphingomyelins Correlate With Plasma T-Tau In Cognitively Unimpaired Older Adults At Risk Of Developing Alzheimer's Disease, Tahmida Sharmin, James D. Doecke, Pratishtha Chatterjee, Steve Pedrini, Hamid R. Sohrabi, Nicholas J. Ashton, Henrik Zetterberg, Manohar L. Garg, Kaj Blennow, Ralph N. Martins

Research outputs 2022 to 2026

Alterations in plasma sphingomyelin (SM) levels have been reported in Alzheimer's disease (AD), pointing to disturbances in lipid metabolism that may contribute to disease pathogenesis. Neuronal damage in early AD triggers tau release into central and peripheral systems. Despite influence from peripheral contributions, alterations in plasma total-tau (T-tau) remain valuable in indicating AD-related neurodegeneration. Investigating relationships between SM metabolism and tau release during preclinical AD may uncover important biochemical processes and support advancing early non-invasive detection and treatment approaches. This cross-sectional study investigated cognitively unimpaired (CU) older adults from the KARVIAH cohort, grouped by cortical amyloid-β (Aβ) status through positron …

Efficient In Vivo Pharmacological Inhibition Of Δfosb, An Ap-1 Transcription Factor, In The Brain, Sean Mcneme, Anil Kumar, Yun Young Yim, Brandon W Hughes, Corey St Romain, Yi Li, Ashwani Kumar, Qichao Bao, Molly Estill, Shanghua Fan, Nadeen Takatka, Earnest P Chen, Matthew Rivera, Haiying Chen, Alfred J Robison, Mischa Machius, Stephen J Haggarty, Jeannie Chin, Eric J Nestler, Jia Zhou, Gabby Rudenko

Faculty, Staff and Students Publications

ΔFOSB, an unusually stable member of the AP-1 family of transcription factors, mediates long-term maladaptations that play a key role in the pathogenesis of drug addiction, cognitive decline, dyskinesia, and several other chronic neurological and psychiatric conditions. We have recently identified that 2-phenoxybenzenesulfonic acid-containing compounds disrupt the binding of ΔFOSB to DNA in vitro in cell-based assays, and one such compound, JPC0661, disrupts ΔFOSB binding to genomic DNA in vivo in the mouse brain with partial efficiency. JPC0661 binds to a groove outside of the DNA-binding cleft of the ΔFOSB/JUND bZIP heterodimer in a cocrystal structure. Here, we generated a …

Dual Orexin Receptor Antagonism With Lemborexant Enhances Microglial Clearance Of Β-Amyloid In Mice, Ashish Sharma, Emiko Segawa, Xiaoying Chen, Sohui Park, Shoutang Wang, Riley E. Irmen, Nicholas J. Constantino, Chanung Wang, Michael F. Kanan, Marco Colonna, Shannon L. Macauley, Jocelyn Y. Cheng, Ken Hatanaka, Margaret Moline, Erik S. Musiek

Sanders-Brown Center on Aging Faculty Publications

Background: Sleep disturbances elevate brain amyloid-beta (Aβ) levels and represent a modifiable risk factor for Alzheimer’s disease (AD). The orexin/hypocretin system regulates sleep–wake behavior and has emerged as a therapeutic target in AD; however, the effects of FDA-approved dual orexin receptor antagonists (DORAs) on amyloid pathology remain unclear. We compared lemborexant, an FDA-approved DORA, to doxepin, an antihistaminergic sleep medication, on amyloid pathology and microglial responses in PSAPP mice.

Methods: PSAPP mice received lemborexant (10 or 30 mg/kg/day), doxepin (35 mg/kg/day), or vehicle for 6 weeks beginning prior to plaque onset or 4 weeks after established pathology. Sleep was assessed …

Insulin Resistance As A Mediator Of Physical Activity's Effects On Beta-Amyloid Accumulation And Tau Phosphorylation: A Scoping Review, Michael G. Slee, Joanne Scotney, Stephanie R. Rainey-Smith, Kirk I. Erickson, Hamid R. Sohrabi, Giuseppe Verdile, Belinda M. Brown

Research outputs 2022 to 2026

Background Type 2 diabetes is associated with increased Alzheimer’s disease risk and brain beta amyloid (Aβ) burden, suggesting an underlying mechanistic relationship between Alzheimer’s disease and type 2 diabetes. Animal studies show exercise reduces levels of brain Aβ and tau, and while human studies are somewhat limited, some studies have reported physical activity is associated with lower brain Aβ and tau levels. Exercise has well established links to reductions in insulin resistance; thus, as physical activity can impact both insulin resistance and Alzheimer’s disease pathology and/or biomarkers, it is reasonable to hypothesise that a mediating relationship may exist. The objective …

Plasma Aβ42/40 Predicts Progression From Aβ-Amyloid Negative To Positive Pet Scans, Azadeh Feizpour, Vincent Doré, Pierrick Bourgeat, James D. Doecke, Rodrigo Canovas, Simon M. Laws, Tenielle Porter, Kun Huang, Christopher Fowler, Ralph N. Martins, Paul Maruff, Hamid R. Sohrabi, Michael W. Weiner, John C. Morris, Tammie L.S. Benzinger, Suzanne E. Schindler, Randall J. Bateman, Yan Li, Ovod Vitaliy, Larry Ward, Jurgen Mejan-Fripp, Colin L. Masters, Victor L. Villemagne, Christopher C. Rowe

Research outputs 2022 to 2026

Background The agreement between plasma Aβ42/40 and Aβ positron emission tomography (PET) is approximately 75 %, with ∼85 % of discrepancies due to positive plasma but negative PET results. It is unclear whether this reflects Aβ changes in plasma before PET-detectable. Objectives To assess the influence of Aβ42/40 positivity on risk of progression to Aβ PET positivity, and feasibility of using plasma Aβ42/40 tests to enrich a primary prevention trial. Design A prospective longitudinal cohort study. Setting Participants of Australian Imaging, Biomarkers and Lifestyle study (AIBL), Alzheimer’s Disease Neuroimaging Initiative (ADNI), and Open Access Series of Imaging Studies 3 (OASIS3). …

Relationship Between Cytomegalovirus Antibody Levels And Cognitive Performance Is Dependent On Age And Genetic Risk, Michael Vacher, Silvia Lee, Patricia Price, Phuongnhi Ha, Shelley Waters, Simon M. Laws

Research outputs 2022 to 2026

Human cytomegalovirus (CMV) is endemic worldwide. It is often acquired in childhood and persists throughout adult life. CMV is linked with several diseases of aging, but associations with cognitive performance are not consistent. Here we address whether this may reflect a dependence on putative genetic determinants, Apolipoprotein E (APOE) ε4 and Tumour Necrosis Factor (TNF), and/or the age of the subjects tested. CMV-reactive antibodies were quantitated in 419 individuals aged 71.7 [53.2—89.1] years, drawn from the Australian Imaging, Biomarker & Lifestyle (AIBL) study. Cognitive composite scores, covering five domains, a global score of cognitive performance, brain amyloid-β (Aβ) burden and …

Alzheimer’S Disease Biological Pet Staging Using Plasma P217+Tau, Azadeh Feizpour, Vincent Doré, Natasha Krishnadas, Pierrick Bourgeat, James D. Doecke, Ziad S. Saad, Gallen Triana-Baltzer, Simon M. Laws, Rosita Shishegar, Kun Huang, Christopher Fowler, Larry Ward, Colin Masters, Jurgen Fripp, Hartmuth Kolb, Victor Villemagne, Christopher Rowe

Research outputs 2022 to 2026

Background: Plasma phospho-tau biomarkers, such as p217+tau, excel at identifying Alzheimer’s disease (AD) neuropathology. However, their ability to substitute for tau PET to identify AD biological stage is unclear. Methods: Participants included 248 cognitively unimpaired (CU) and 227 cognitively impaired (CI) individuals, with Janssen plasma p217+tau Simoa® assay, 18F-NAV4694 Aβ-PET (A) and 18F-MK6240 tau-PET (T) data. Biological PET stages were defined according to the Revised Criteria for Diagnosis and Staging of Alzheimer’s Disease (2024): Initial (A + T-), Early (A + TMTL +), Intermediate (A + TMOD +), and Advanced (A + THIGH +). The threshold for A+ was 25 …

Differential Patterns Of Gut And Oral Microbiomes In Hispanic Individuals With Cognitive Impairment, Yannick N. Wadop, Erin L. Vasquez, Julia J. Mathews, Jazmyn A. S. Muhammad, Rosa P. Mavarez, Claudia Satizabal, Mitzi M. Gonzales, Jeremy A. Tanner, Gladys E. Maestre, Bernard Fongang

School of Medicine Publications

Alterations in both oral and gut microbiomes have been associated with Alzheimer's disease and related dementia (ADRD). While extensive research has focused on the role of gut dysbiosis in ADRD, the contribution of the oral microbiome remains relatively understudied. This study aims to evaluate distinct patterns and potential synergistic effects of oral and gut microbiomes in a cohort of predominantly Hispanic individuals with cognitive impairment (CI) and without cognitive impairment (NC). We conducted 16S rRNA gene sequencing on stool and saliva samples from 32 participants (17 CI, 15 NC; 62.5% female, mean age = 70.4 ± 6.2 years) recruited in …

Ocular Blood Flow And Retinal Vascular Reactivity In Alzheimer’S Disease: A Systematic Review Of Retinal Images, Tori Sayers, Alexa Nichols, Amin Ibrahim, Igor Zwir, Andrew Tsin, Lorena Flores-Hernandez, Gladys E. Maestre, Jesus D. Melgarejo

Research Colloquium

Background: Alzheimer’s disease (AD) is the most common form of dementia and one of the leading causes of disability and death in the United States¹. Research efforts aim to identify pathological changes that may help support earlier detection of AD and lead to more accessible tools for monitoring disease progression². The retina is being explored as a potential non-invasive marker of AD, reflecting the shared embryology and microvasculature features between the retina and the brain. Although research has focused on structural changes in retinal vessel diameters and density, few studies have evaluated functional markers of retinal …

The Therapeutic Potential Of Butyrate And Lauric Acid In Modulating Glial And Neuronal Activity In Alzheimer’S Disease, Rathnayaka Mudiyanselage Uththara Sachinthanie Senarath, Lotta E. Oikari, Prashant Bharadwaj, Vijay Jayasena, Ralph N. Martins, Wanakulasuriya Mary Ann Dipika Binosha Fernando

Research outputs 2022 to 2026

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder marked by amyloid-β plaque accumulation, tau tangles, and extensive neuroinflammation. Neuroinflammation, driven by glial cells like microglia and astrocytes, plays a critical role in AD progression. Initially, these cells provide protective functions, such as debris clearance and neurotrophic support. However, as AD progresses, chronic activation of these cells exacerbates inflammation, contributing to synaptic dysfunction, neuronal loss, and cognitive decline. Microglia release pro-inflammatory cytokines and reactive oxygen species (ROS), while astrocytes undergo reactive astrogliosis, further impairing neuronal health. This maladaptive response from glial cells significantly accelerates disease pathology. Current AD treatments primarily aim …

The Impact Of Type 2 Diabetes Mellitus On The Severity Of Alzheimer's Disease In Hispanic Populations In The Rio Grande Valley: A Pilot Retrospective Chart Review, Maria Camila Gonzalez Tovar, Daniel Salinas, Kelsey Baker

School of Medicine Publications

Background: Alzheimer's disease (AD) is becoming more prevalent worldwide, leading to a growing demand to understand the impact of risk factors on disease progression. Notably, type 2 diabetes mellitus (DM) has emerged as a significant risk factor for the development of AD, given the pathophysiological role of insulin resistance in cognitive impairment. In particular, the impact of type 2 DM on AD development and severity may be heightened in Hispanic populations due to the high prevalence of both conditions in this community. Here, we sought to understand the role of type 2 DM in AD severity in a Hispanic population …

Alzheimer’S Disease Protective Allele Of Clusterin Modulates Neuronal Excitability Through Lipid-Droplet-Mediated Neuron-Glia Communication, Xiaojie Zhao, Yan Li, Siwei Zhang, Ari Sudwarts, Hanwen Zhang, Alena Kozlova, Matthew J Moulton, Lindsey D Goodman, Zhiping P Pang, Alan R Sanders, Hugo J Bellen, Gopal Thinakaran, Jubao Duan

Duncan NRI Faculty and Staff Publications

Background: Genome-wide association studies (GWAS) of Alzheimer's disease (AD) have identified a plethora of risk loci. However, the disease variants/genes and the underlying mechanisms have not been extensively studied.

Methods: Bulk ATAC-seq was performed in induced pluripotent stem cells (iPSCs) differentiated various brain cell types to identify allele-specific open chromatin (ASoC) SNPs. CRISPR-Cas9 editing generated isogenic pairs, which were then differentiated into glutamatergic neurons (iGlut). Transcriptomic analysis and functional studies of iGlut co-cultured with mouse astrocytes assessed neuronal excitability and lipid droplet formation.

Results: We identified a putative causal SNP of CLU that impacted neuronal chromatin accessibility to transcription-factor(s), with …

Dna Methylation Signature Of A Lifestyle-Based Resilience Index For Cognitive Health, Wei Zhang, David Lukacsovich, Juan I Young, Lissette Gomez, Michael A Schmidt, Eden R Martin, Brian W Kunkle, X Steven Chen, Deirdre M O'Shea, James E Galvin, Lily Wang

Faculty, Staff and Students Publications

Cognitive resilience (CR) contributes to the variability in risk for developing and progressing in Alzheimer's disease (AD) among individuals. Beyond genetics, recent studies highlight the critical role of lifestyle factors in enhancing CR and delaying cognitive decline. DNA methylation (DNAm), an epigenetic mechanism influenced by both genetic and environmental factors, including CR-related lifestyle factors, offers a promising pathway for understanding the biology of CR. We studied DNAm changes associated with the Resilience Index (RI), a composite measure of lifestyle factors, using blood samples from the Healthy Brain Initiative (HBI) cohort. After corrections for multiple comparisons, our analysis identified 19 CpGs …

Identification Of Retinal Microvasculature Associated With Alzheimer’S Disease-Related Disorders Using Optical Tomography Coherence Angiography: A Systematic Review, Giani C. Tah, Silvia Mejia-Arango, Igor Zwir, Lorena Flores-Hernandez, Gladys E. Maestre, Jesus D. Melgarejo

Research Symposium

Introduction: Alzheimer’s dementia (AD) is the most common type of form of dementia in older adults. Detection and diagnosis are based on invasive and expensive procedures including PET scanning and lumbar puncture cerebrospinal fluid analysis. Optical Tomography Coherence (OCT) angiography may be an alternative solution for early, cost-effective non-invasive detection of AD. We aimed to conduct a systematic review to summarize the current evidence describing the association between OCT angiography and AD using PubMed as data source.

Methods: Pubmed was used to compile resources for a systematic review. Keywords used include “Alzheimer’s disease”, “preclinical Alzheimer’s disease”, “OCT”, “OCTA”, “neurovascular degeneration”, …

Investigating The Impact Of Sorghum On Tau Protein Phosphorylation And Mitochondrial Dysfunction Modulation In Alzheimer’S Disease: An In Vitro Study, Nasim Rezaee, Eugene Hone, Hamid Sohrabi, Rasheed Abdulraheem, Stuart K. Johnson, Stuart Gunzburg, Ralph N. Martins, W. M.A.D.Binosha Fernando

Research outputs 2022 to 2026

Background: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder with poorly understood pathology. Elevated tau, phospho-tau and mitochondrial dysfunction are significantly correlated with an increased risk of AD and are therefore targets for disease-modifying therapy. In this study, we examined the effects of polyphenolic extracts from six different varieties of sorghum: Shawaya short black-1 (Black), IS1311C (Brown), QL33/QL36 (Red), B923296 (Red), QL12 (White), and QL33 (Red) on the attenuation of beta amyloid-induced phospho-tau levels, total tau levels, and mitochondrial dysfunction in neuronal cells. Method: Tau proteins (231 (pT231), Serine- 199 (pS199), and total tau proteins (T-tau)) were detected and quantified …

Disrupted Calcium Dynamics In Reactive Astrocytes Occur With End Feet–Arteriole Decoupling In An Amyloid Mouse Model Of Alzheimer’S Disease, Blaine Weiss, John C. Gant, Ruei-Lung Lin, Jenna L. Gollihue, Colin B. Rogers, Susan D. Kraner, Edmund B. Rucker, Yuriko Katsumata, Yang Jiang, Peter T. Nelson, Donna M. Wilcock, Pradoldej Sompol, Olivier Thibault, Christopher M. Norris

Sanders-Brown Center on Aging Faculty Publications

While cerebrovascular dysfunction and reactive astrocytosis are extensively characterized hallmarks of Alzheimer's disease (AD) and related dementias, the dynamic relationship between reactive astrocytes and cerebral vessels remains poorly understood. Here, we used jGCaMP8f and two-photon microscopy to investigate calcium signaling in multiple astrocyte subcompartments, concurrent with changes in cerebral arteriole activity, in fully awake 7- to 8-month-old male and female 5xFAD mice, a model for AD-like pathology, and wild-type (WT) littermates. In the absence of movement, spontaneous calcium transients in barrel cortex occurred more frequently in astrocyte somata, processes, and perivascular regions of 5xFAD mice. However, evoked arteriole dilations (in …

Blood Biomarker Profiles In Young-Onset Neurocognitive Disorders: A Cohort Study, Oneil G. Bhalala, Jessica Beamish, Dhamidhu Eratne, Patrick Summerell, Tenielle Porter, Simon M. Laws, Matthew J.Y. Kang, Aamira J. Huq, Wei Hsuan Chiu, Claire Cadwallader, Mark Walterfang, Sarah Farrand, Andrew H. Evans, Wendy Kelso, Leonid Churilov, Rosie Watson, Nawaf Yassi, Dennis Velakoulis, Samantha M. Loi

Research outputs 2022 to 2026

Introduction: Young-onset neurocognitive symptoms result from a heterogeneous group of neurological and psychiatric disorders which present a diagnostic challenge. To identify such factors, we analysed the Biomarkers in Younger-Onset Neurocognitive Disorders cohort, a study of individuals < 65 years old presenting with neurocognitive symptoms for a diagnosis and who have undergone cognitive and biomarker analyses. Methods: Sixty-five participants (median age at assessment of 56 years, 45% female) were recruited during their index presentation to the Royal Melbourne Hospital Neuropsychiatry Centre, a tertiary specialist service in Melbourne, Australia, and categorized as either early-onset Alzheimer’s disease (n = 18), non-Alzheimer’s disease neurodegeneration (n = 23) or primary psychiatric disorders (n = 24). Levels of neurofilament light chain, glial fibrillary acidic protein …

The Role Of Glial Fibrillary Acidic Protein In The Neuropathology Of Alzheimer’S Disease And Its Potential As A Blood Biomarker For Early Diagnosis And Progression, Ekanayaka M.S. Bandara, Prita R. Asih, Steve Pedrini, Eugene Hone, Warnakulasuriya Mary Ann Dipika Binosha Fernando, Ralph N. Martins

Research outputs 2022 to 2026

Alzheimer’s disease (AD) is a neurodegenerative disease characterised by neuropathological hallmarks, including extracellular amyloid plaques and neurofibrillary tangles. The disease is clinically defined by cognitive dysfunction, including learning, memory deficits, and behavioural changes. With the rising global prevalence of AD, early diagnosis is critical for implementing effective interventions before irreversible neuronal damage occurs. Biomarkers correlating amyloid deposition, tau pathology, neuroinflammation, and neurodegeneration are currently being investigated using cerebrospinal fluid analysis and positron emission tomography imaging. These methods are invasive or costly, limiting their widespread clinical utility. Blood-based biomarkers offer a promising alternative due to accessibility, cost-effectiveness, and feasibility for large-scale …

Simple Improvements In Vector Design Afford Substantial Gains In Aav Delivery Of Aggregation-Slowing Aβ Variants, Ella Borgenheimer, Cameron Trueblood, Bryan L Nguyen, William R Lagor, Joanna L Jankowsky

Faculty, Staff and Students Publications

Adeno-associated virus (AAV) gene therapy for neurological disease has gained traction due to stunning advances in capsid evolution for CNS targeting. With AAV brain delivery now in focus, conventional improvements in viral expression vectors offer a complementary route for optimizing gene delivery. We previously introduced a novel AAV gene therapy to slow amyloid aggregation in the brain based on neuronal release of an Aβ sequence variant that inhibited fibrilization of wild-type Aβ. Here we explore three coding elements of the virally delivered DNA plasmid in an effort to maximize the production of therapeutic peptide in the brain. We demonstrate that …

Cyp1b1-Rmdn2 Alzheimer’S Disease Endophenotype Locus Identified For Cerebral Tau Pet, Kwangsik Nho, Shannon L. Risacher, Liana G. Apostolova, Paula J. Bice, Jared R. Brosch, Rachael Deardorff, Kelley Faber, Martin R. Farlow, Tatiana Foroud, Sujuan Gao, Thea Rosewood, Jun Pyo Kim, Kelly Nudelman, Meichen Yu, Paul Aisen, Reisa Sperling, Basavaraj Hooli, Sergey Shcherbinin, Diana Svaldi, Clifford R. Jack, William J. Jagust, Susan Landau, Aparna Vasanthakumar, Tenielle Porter, Vincent Doré, Simon M. Laws

Research outputs 2022 to 2026

Determining the genetic architecture of Alzheimer’s disease pathologies can enhance mechanistic understanding and inform precision medicine strategies. Here, we perform a genome-wide association study of cortical tau quantified by positron emission tomography in 3046 participants from 12 independent studies. The CYP1B1-RMDN2 locus is associated with tau deposition. The most significant signal is at rs2113389, explaining 4.3% of the variation in cortical tau, while APOE4 rs429358 accounts for 3.6%. rs2113389 is associated with higher tau and faster cognitive decline. Additive effects, but no interactions, are observed between rs2113389 and diagnosis, APOE4, and amyloid beta positivity. CYP1B1 expression is upregulated in AD. …

Alzheimer’S Disease Risk Gene Cd2ap Is A Dose-Sensitive Determinant Of Synaptic Structure And Plasticity, Matea Pavešković, Ruth B De-Paula, Shamsideen A Ojelade, Evelyne K Tantry, Mikhail Y Kochukov, Suyang Bao, Surabi Veeraragavan, Alexandra R Garza, Snigdha Srivastava, Si-Yuan Song, Masashi Fujita, Duc M Duong, David A Bennett, Philip L De Jager, Nicholas T Seyfried, Mary E Dickinson, Jason D Heaney, Benjamin R Arenkiel, Joshua M Shulman

Duncan NRI Faculty and Staff Publications

CD2-Associated protein (CD2AP) is a candidate susceptibility gene for Alzheimer's disease, but its role in the mammalian central nervous system remains largely unknown. We show that CD2AP protein is broadly expressed in the adult mouse brain, including within cortical and hippocampal neurons, where it is detected at pre-synaptic terminals. Deletion of Cd2ap altered dendritic branching and spine density, and impaired ubiquitin-proteasome system activity. Moreover, in mice harboring either one or two copies of a germline Cd2ap null allele, we noted increased paired-pulse facilitation at hippocampal Schaffer-collateral synapses, consistent with a haploinsufficient requirement for pre-synaptic release. Whereas conditional Cd2ap knockout in …

Investigating Genetic Overlap Between Alzheimer’S Disease, Lipids, And Coronary Artery Disease: A Large-Scale Genome-Wide Cross Trait Analysis, Artika Kirby, Tenielle Porter, Emmanuel O. Adewuyi, Simon M. Laws

Research outputs 2022 to 2026

There is evidence to support a link between abnormal lipid metabolism and Alzheimer’s disease (AD) risk. Similarly, observational studies suggest a comorbid relationship between AD and coronary artery disease (CAD). However, the intricate biological mechanisms of AD are poorly understood, and its relationship with lipids and CAD traits remains unresolved. Conflicting evidence further underscores the ongoing investigation into this research area. Here, we systematically assess the cross-trait genetic overlap of AD with 13 representative lipids (from eight classes) and seven CAD traits, leveraging robust analytical methods, well-powered large-scale genetic data, and rigorous replication testing. Our main analysis demonstrates a significant …

Assessment Of Brain-Derived Extracellular Vesicle Enrichment For Blood Biomarker Analysis In Age-Related Neurodegenerative Diseases: An International Overview, Amanpreet Badhwar, Yael Hirschberg, Natalia Valle-Tamayo, Florencia Iulita, Chinedu Momoh, Anna Matton, Rawan Tarawneh, Robert Rissman, Aurélie Ledreux, Charisse Winston

Brain and Mind Institute

INTRODUCTION Brain-derived extracellular vesicles (BEVs) in blood allows for minimally-invasive investigations of central nervous system (CNS) -specific markers of age-related neurodegenerative diseases (NDDs). Polymer-based EV- and immunoprecipitation (IP)-based BEV-enrichment protocols from blood have gained popularity. We systematically investigated protocol consistency across studies, and determined CNS-specificity of proteins associated with these protocols.

METHODS NDD articles investigating BEVs in blood using polymer-based and/or IP-based BEV enrichment protocols were systematically identified, and protocols compared. Proteins used for BEV-enrichment and/or post-enrichment were assessed for CNS- and brain-cell-type-specificity, extracellular domains (ECD+), and presence in EV-databases.

RESULTS A total of 82.1% of studies used polymer-based (ExoQuick) …