Investigating Immunisation Strategies for the Treatment of Synucleinopathies

Overview
Next generation immunisation strategies have enabled the manufacture of highly efficacious vaccines to treat major global diseases which are currently untreatable. United Neuroscience (UNS), a biotechnological company, has aimed to overcome the current vaccine challenges in the field of neurodegenerative disease by designing highly targeted vaccines which elicit a protective immune response. Synucleinopathies comprise a group of neurodegenerative diseases that are characterised by primary alpha-synuclein (α-Syn) pathology such as Dementia with Lewy Bodies (DLB), Parkinson’s disease (PD) and Multiple systems atrophy (MSA). The central role of α-Syn in the pathogenesis of these diseases highlights it as a promising target for therapy. In this study we aim to test the effects of novel α-Syn vaccines developed by UNS on preventing the onset and progression of neurodegeneration in mouse models of these synucleinopathies. In order to investigate this, we first need to understand the pathway along which α-Syn is naturally cleared from the brain and we can then establish how immunotherapy modulates this process and evaluate the neuroprotective effects of this as a treatment.
Funding
United Neuroscience project grant – “Pathology and mechanisms of immunization in neurodegenerative diseases” £240,000

Failure of drainage of fluid from the brain along the walls of blood vessels in vascular dementia

Overview
Cerebral small vessel disease (SVD) is a key feature of vascular dementia, radiologically defined by the presence of white matter hyperintensities, lacunar infarcts, microbleeds and perivascular spaces.  Cerebral arteriolosclerosis resulting in loss of elasticity and segmental disorganisation of the arterial wall leads to damage of the deep white matter.  The primary functions of penetrating and perforating cerebral arteries supplying blood and drainage of fluid and solutes from the parenchyma along IPAD pathways are impaired.  In this project, using animal models and post-mortem brain tissue from stroke survivors with SVD (CogFAST study) along with light sheet 3D microscopy and post-mortem MRI, we will assess the immunocytochemical pattern of distribution of AQP4, α-dystrobrevin and β-dystroglycan.  We will then test the hypotheses that 1) disruption in the anchoring system of the basement membranes such as that observed in α-dystrobrevin knock-out mice and 2) disruption of gliovascular end feet tracked by aquaporin 4 (AQP4) knock-out mice there is failure of perivascular clearance of fluid from the deep gray matter and the corpus callosum.  Our aim is to demonstrate that failure of perivascular drainage of fluid from the brain is a mechanism underlying SVD and this could be targeted therapeutically.
Funding
Stroke Association Priority Programme Award (vascular dementia) – “Failure of drainage of fluid from the brain along the walls of blood vessels in vascular dementia“. £245,198.00
Key publications
Apr 2018
Small vessels, dementia and chronic diseases – molecular mechanisms and pathophysiology.
Horsburgh K, Wardlaw JM, van Agtmael T, Allan SM, Ashford MLJ, Bath Philip M, et al.

 

Feb 2018
The fine anatomy of the perivascular compartment in the brain. Relevance to dilated perivascular spaces in cerebral amyloid angiopathy.
MacGregor Sharp M, Bulters D, Brandner S, Holton J, Verma A, Carare R.O, Werring D.

In vivo MRI imaging of the motive force driving intramural perivascular clearance

Overview
Based on results from mathematical modelling we now know that the motive force for IPAD is provided by spontaneous vasomotion resulting from the intrinsic contractions of pericytes and cerebrovascular smooth muscle cells and not by the pulsations derived from cardiac cycle (Dr Alexandra Diem, Prof Neil Bressloff). Collaborations are in place with senior neuroradiologists in University College London and Leiden, The Netherlands to demonstrate in vivo in real time using MRI, the features of the motive force for efficient IPAD clearance and correlate this with findings in different stages of Alzheimer’s disease and mild cognitive impairment. This could be the first marker for impaired clearance of cerebral interstitial fluid in humans.
Funding
EPSRC Doctoral Prize
Key publications
Mar 2016
Lymphatic Clearance of the Brain: Perivascular, Paravascular and Significance for Neurodegenerative Diseases
Bakker E.N, Bacskai B.J, Arbel-Ornath M, Aldea R, Bedussi B, Morris A.W.J, Weller R.O, Carare R.O.

Development of an in vitro perivascular clearance system

Overview
Using a novel Quasi Vivo in vitro system developed by Kirkstall Ltd and mouse astrocytes that express humanised ApoE, (collaboration with David Holtzman, Washington University, USA), we aim to test the hypothesis that flow of Aβ over astrocytes expressing different forms of ApoE results in morphological alterations to the astrocytes expressing ApoE4, compared to those expressing ApoE2 or ApoE3.

Using coated coverslips, the astrocytes are plated and left to adhere for 24 hours before being loaded into the QV500 chamber or 24 well plate for static experiments. A solution of astrocyte growth medium supplemented with 100nM Aβ 1-40 is circulated around the system for 24 hours. The coverslip is removed and fixed in 4% PFA, immunostained and examined by confocal microscopy. We have already optimised the system for testing the activity of Quasi Vivo and concluded that the Quasi Vivo system has no significant toxic effect on the growth or viability of the cells when cells grown under flow were compared with static controls. There appears to be a decrease in cell number when Aβ is applied to ApoE4 astrocytes under flow. We have also shown that there are morphological changes to ApoE4 astrocytes when Aβ is applied that are further enhanced when combined with flow. These changes are not seen in ApoE2 or ApoE3 astrocytes. We also observed that Aβ appears to be concentrated where there are clusters of cells, though this has only been seen in ApoE3 astrocytes. This work suggests that the dynamics of interactions between Aβ and astrocytes are dependent on their APOE genotype and this is likely to contribute to the reduced clearance of Aβ in APOE4 individuals.

Funding
BBSRC CASE PhD Studentship with Kirkstall Ltd – “Development of an in vitro perivascular clearance system“. £95,042

Does maternal high fat diet lead to dementia?

Overview
In this project we test the hypothesis that exposure to a high fat diet during development and early life, leads to the remodelling of the neurovascular unit and reduces the efficiency of Aβ clearance from the brain, leading to increased CAA severity. A mouse model of pre- and postnatal high fat diet exposure will be established by feeding female mice (C57Bl/6), either a standard (21% kcal fat) or high fat (45% kcal fat) diet for 4 weeks before conception and during gestation and lactation. At weaning, male and female offspring will be fed either a normal or high fat to generate 4 groups of experimental mice. We will create a separate group of female pregnant mice that will be treated with Metformin to assess whether this therapeutic agent is effective in halting the pathological process. We aim to demonstrate that simple measures like improving the diet of pregnant mothers and managing hypercholesterolaemia and diabetes will prevent or delay the onset of dementia.
Funding
Rosetrees Trust Project grant – “The effect of maternal high fat on the clearance of interstitial fluid from the brain“. £25,000.

Innervation of cerebral arteries is key to maintenance of efficient clearance and flow

Overview
This project, funded by Alzheimer’s Research UK in collaboration with Dr Cheryl Hawkes (Open University), tests the hypothesis that loss of perivascular innervation by cholinergic neurons leads to dysfunctional regulation of vascular tone, thereby reducing the motive force for perivascular drainage of Aβ leading to a worsening of cerebral amyloid angiopathy.
Funding
Alzheimer’s Research UK – Co-PI “Targeting perivascular innervation and vascular tone for improved clearance of ß-amyloid from the brain“. £88,440