Probing Aβ Dynamics in APP Knock-In Mice and in vitro Using Stable Isotope Labelling and MALDI Imaging Mass Spectrometry, and Examining the Role of Microglia
Katie Stringer (1,2), Wojciech Michno (2), Frances Edwards (1), Jörg Hanrieder (1,2) (1) University College London, UK, (2) University of Gothenburg, Sweden
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Katie Stringer (Presenter) University College London
Presenter Bio: Katie Stringer is a PhD student at the Department of Neuroscience at University College London supervised by Jörg Hanrieder and Frances Edwards. She also holds a guest appointment at the Neurochemistry division at the Sahlgrenska Academy, University of Gothenburg, Sweden. Her current research is focused on the investigation of amyloid aggregation dynamics that underlie pathogenic processes in AD by means of multimodal imaging mass spectrometry.
Katie holds a BSc Hon Experimental Psychology from Bristol University, and an MSc in Neuroscience specialising in Neurodegeneration from Kings College London that she obtained in 2016. In 2017, she joined the group of Prof Frances Edwards at UCL and Dr. Jörg Hanrieder at UCL and GU. Her current work includes the investigation of chemical factors that underlie the progression of Alzheimer’s disease pathology in novel model systems mimicking AD pathology.
Relevant Financial Disclosures
(within past 24 months)
No relevant financial relationship(s) to disclose.
Abstract
Introduction
Amyloid beta (Aβ) plaque deposition is a major pathological feature of Alzheimer’s disease (AD); however, this exact process remains unclear. Moreover, the relationship between plaques, soluble Aβ and microglia is controversial.
Objectives:
We aim to assess Aβ deposition and plaque composition in detail both in vivo and in an organotypic hippocampal slice culture (OHSC) model obtained from amyloid precursor protein (APP) knock-in mice (APPNL-F and APPNL-G-F), and also assess the interaction with microglia.
Methods:
OHSCs were made from P5-7 WT and APPNL-G-F mice. For both, plaque pathology was cross-seeded by incubation with exogenous Aβ1-40 and Aβ 1-42, and brain homogenate from older plaque-bearing mice. Aggregation and plaque development in OHSCs were examined after 8-12 weeks in culture.
Further incubation with stable isotope-labelled Aβ was used to label plaques developing in vivo. Specific aggregation dynamics of different amyloid species was analysed from both in vitro and in vivo preparations using matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS).
The type, number and distance of microglia around plaques will be characterised in different brain regions in APPNL-F and APPNL-G-F mice.
Results:
After 8 weeks in culture, OHSCs developed amyloid deposits, with the type and number depending on the peptide for incubation. MALDI techniques can distinguish between initial Aβ seeds and later deposition depending on application of labelled isotopes, allowing for assessment of the nature in which the plaque grows. MALDI can also be used to delineate Aβ species associated with plaque formation both in vitro and in vivo.
Discussion and Conclusions:
Cultured slices can be manipulated to develop amyloid pathology, making this a useful model for the efficient study of plaque development in mice. Microglia cluster around Aβ plaques which implicates their role in AD pathology.
MALDI allows for high resolution imaging, elucidating details of timing of plaque deposition, and the type and distribution of Aβ peptides in and around the plaque.
= Discovery stage.
= Translation stage.
= Clinically available.
