Project - Understanding Selective Vulnerability in Alzheimer’s Disease

Research Project Abstract

A key characteristic of Alzheimer’s disease is that specific brain regions are more vulnerable than others. Why this is the case is currently unknown. The goal of this study is to identify the protein changes in the brain that drive selective vulnerability in Alzheimer’s disease. We are using a state-of-the-art proteomics approach to identify protein differences in neuron populations in brain regions that are either particularly vulnerable or particularly resistant in Alzheimer’s disease. Our proteomics approach allows the simultaneous quantification of thousands of proteins at once in neurons that are microdissected directly from human brain tissue. Our results will pinpoint the proteins that have a particularly important role in driving selective vulnerability. The role of these proteins in Alzheimer’s disease will be examined further in mechanistic studies. This project is funded by the Bluesand Foundation and Dementia Australia Research Foundation (2018-2021).

Challenges within the field

Challenge 1: We do not know why neuron populations are selectively vulnerable in Alzheimer’s disease. Here, we will profile all protein changes in vulnerable and resistant neurons in Alzheimer’s disease, which will provide unprecedented insight into the drivers of selective vulnerability.

Challenge 2: No techniques are currently available to quantify protein expression directly in vulnerable neurons. Our state-of-the-art proteomics approach allows us to quantify protein expression directly in specific neurons for the first time.

Research Project Description

Aim 1: Quantify Protein Expression Differences in Vulnerable and Resistant Neurons in Human Alzheimer’s Disease Brain Tissue Neurons from a vulnerable brain region (entorhinal cortex) and a resistant brain region (visual cortex) will be microdissected from post-mortem human brain tissue using laser capture microdissection. Neurons will be microdissected from cases of preclinical Alzheimer’s disease (prior to cognitive impairment), mild cognitive impairment and advanced Alzheimer’s disease to gain insight into the protein changes that occur throughout the progression of Alzheimer’s disease. Mass spectrometry will be used to simultaneously quantify all proteins present in these neuron populations. Bioinformatics approaches will then be used to determine which proteins are driving selective vulnerability.

Aim 2: Validate Key Novel Drivers of Selective Vulnerability Proteins identified to have a key role in potentially driving selective vulnerability in Alzheimer’s disease will be first validated using multiplexed fluorescent immunohistochemistry. Additional validation studies will be performed to determine whether these proteins are driving vulnerability via interaction with the key pathological proteins in Alzheimer’s disease (amyloid beta or tau). This will be done using co-immunoprecipitation followed by mass spectrometry.

Research Objectives

• Identify proteins that are driving selective vulnerability in neurons in Alzheimer’s disease
• Identify new potential drug targets and biomarkers for Alzheimer’s disease
• Generate the first comprehensive database of proteins associated with neuropathology in human Alzheimer’s disease brain tissue.

Key Publications from this project

• Pires G, McElligott S, Drusinsky S, Halliday G, Potier MC, Wisniewski T, Drummond E (2019) Secernin-1 is a novel phosphorylated tau binding protein that accumulates in Alzheimer's disease and not in other tauopathies. Acta Neuropathological Communications, 7(1):195
• Drummond E, Wisniewski T (2019) Using Proteomics to Understand Alzheimer’s Disease Pathogenesis. In: Alzheimer’s Disease. Wisniewski T, editor. Chapter 3: pg 37-51
• Wisniewski T and Drummond E (2019) Future Horizons in Alzheimer’s Disease Research. In: Molecular Biology of Neurodegenerative Diseases: Visions for the Future. Teplow D, editor. Chapter 12; p223-241
• Drummond E, Nayak S, Ueberheide B, Wisniewski T (2017) Localized Proteomics of Individual Neurons Isolated from Formalin-Fixed, Paraffin Embedded Tissue Sections using Laser Capture Microdissection. In: Current Proteomic Approaches Applied to Brain Function. Santamaria E, Fernández J, editors. New York City: Humana Press; p289-301

Infographic / Medical Diagram / Scientific Diagram / Picture

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Key Findings

Key findings: The identification of novel proteins that are driving vulnerability and resistance in Alzheimer’s disease

Impact on Disease: Our findings will provide new potential drug targets and biomarkers for Alzheimer’s disease.

Project - Identification of the phosphorylated tau interactome in frontotemporal dementia

Research Project Abstract

Tau is the central pathological protein in more than 20 types of neurodegenerative disease, which are collectively called tauopathies. Despite the known central role of tau in all these diseases, our current understanding about how tau causes toxicity and neurodegeneration is limited. The aim of this project is to identify all proteins that interact with pathological tau in different types of tauopathy (Alzheimer’s disease, progressive supranuclear palsy, corticobasal degeneration and Pick’s disease). To do this we will perform co-immunoprecipitation to pull down pathological tau from human brain tissue samples, which we will then analyse using proteomics to identify all proteins that interact with pathological tau. Our study will provide novel insight into the different ways that tau causes toxicity in these diseases. This project is funded by the Brain & Mind Centre, University of Sydney (2020).

Challenges within the field

Challenge 1: We don’t know how tau causes neurodegeneration and dementia. In this project we will provide novel insight into how tau contributes to disease in multiple different types of tauopathies by simultaneously quantifying hundreds of proteins that interact with pathological tau in human brain tissue samples.

Challenge 2: We don’t yet know why tau causes different types of tauopathy. Our direct comparison of four major types of tauopathy will allow us to identify proteins that tau uniquely interact with in each disease, which will provide insight into why tau causes multiple different diseases

Research Project Description

Aim 1: Identify proteins that interact with pathological tau in different types of tauopathy. We will use co-immunoprecipitation to pull down pathological, phosphorylated tau from human brain tissue samples from cases of Alzheimer’s disease, progressive supranuclear palsy, corticobasal degeneration and Pick’s disease. We will then use mass spectrometry to identify all proteins that interact with pathological tau in these diseases. We will then compare these data to identify similarities and differences between different tauopathies.

Aim 2: Validation and mechanistic studies for novel proteins that show a particularly strong interaction with pathological tau. We will validate our findings using multiplexed fluorescent immunohistochemistry to confirm that proteins identified by mass spectrometry co-localize with tau aggregates. We will then perform mechanistic cell culture studies to determine whether these interactions accelerate tau aggregation and cell death.

Research Objectives

• To identify how tau causes toxicity in different diseases
• Identify new potential drug targets and biomarkers for frontotemporal dementia and Alzheimer’s disease
• Generate the first comprehensive database of proteins that interact with pathological tau.

Key Publications from this project

Pires G, McElligott S, Drusinsky S, Halliday G, Potier MC, Wisniewski T, Drummond E (2019) Secernin-1 is a novel phosphorylated tau binding protein that accumulates in Alzheimer's disease and not in other tauopathies. Acta Neuropathological Communications, 7(1):195

Infographic / Medical Diagram / Scientific Diagram / Picture

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Key Findings

We have identified 125 proteins that interact with pathological tau in Alzheimer’s disease human brain tissue, which are new potential drug targets for Alzheimer’s disease (and potentially other tauopathies).