Funded PhD positions -
Funded PhD positions -
Developing new acute treatments for stroke by targeting the cytokine interleukin-1
Acute brain injury caused by stroke is a leading cause of global death and disability. Despite decades of research there is still no widely available effective treatment for stroke, and it remains an area of significant unmet need. In ischaemic stroke pharmacologic or physical (tPA or endovascular thrombectomy respectively) methods to remove the clot and provide reperfusion can be effective but require optimal clinical services and are not applicable to all strokes and carry significant risk (1). In ischaemic stroke the earlier a treatment is started the better with regards reducing brain injury and improving outcomes, the ideal scenario being pre-hospital treatment. This is not possible with tPA as it is contraindicated for brain haemorrhage. We and others have shown that interleukin-1 receptor antagonist (IL-1Ra – or anakinra), a clinically approved anti-inflammatory drug, protects against neuronal damage in preclinical models of stroke and acute brain injury, with early-stage clinical trials also completed (2). Anakinra is therefore an attractive candidate as a pre-hospital treatment for stroke and other acute brain injuries. A recent early phase trial in ischaemic stroke (3) and our own preclinical studies have however highlighted potential negative interactions with combined tPA and anakinra treatment, which we aim to further explore in this project. We hope that by shifting anakinra treatment ahead of tPA we will avoid the negative interactions, which would align well with pre-hospital treatment. However, it may be that anakinra is not the ideal inhibitor of IL-1 so we will also study the novel IL-1 antagonist, isunakinra, a chimeric protein with improved efficacy over anakinra. Our pilot data show that isunakinra avoids some of the issues when given with tPA and we aim to investigate this further here, as well as directly compare the efficacy of anakinra versus isunakinra in preclinical stroke models. Isunakinra is licensed for clinical use so could be rapidly developed as a new treatment for stroke and other acute brain injuries where inflammation and IL-1 has been implicated. Overall, we hope that this project will help in the development of new acute treatments for ischaemic stroke.
Supervised by:
Prof Stuart Allan
Prof Craig Smith
Dr Ioana-Emilia Mosneag
Discovering ways to help the brain to repair after intracerebral haemorrhage
Intracerebral haemorrhage is a type of stroke that occurs when a blood vessel suddenly ruptures and begins bleeding into the brain. Blood that is now in the brain contains various cells (including red blood cells) that start to release toxic factors that can cause further damage to brain cells. It is important therefore, to try and get rid of the blood as quickly as possible, to reduce the chances of it causing any harm. Our tissues/organs contain a group of cells called phagocytes whose job is to eat any harmful cells and smaller particles to try to protect our bodies from any of their harmful effects. In haemorrhagic stroke, these phagocytes try to eat up the red blood cells and toxic factors. However, this job can take time and trying to find a way to help the phagocytes get rid of the blood quicker and more efficiently would help to prevent further damage to the brain. We have discovered that the amount of a protein called cholesterol 25-hydroxylase (Ch25h) goes up in the phagocytes (microglia and monocyte-derived macrophages) in the brain after haemorrhage, and we believe that this protein might help the phagocytes to work better to clear away the blood and other cellular debris.
The aim of this PhD, therefore, is to use animal and in vitro models of brain haemorrhage as well as tissue from patients who died from this condition to learn more about what Ch25h is doing in the brain. Specifically, the project will determine if Ch25h can help the phagocytes to remove blood and other debris produced after a haemorrhage. This project provides a great opportunity to join a vibrant research group, and the student will receive an interdisciplinary training in an exciting area of research, which will hopefully contribute to identifying a potential new way to improve outcome and reduce the negative impact of haemorrhagic stroke, a life-threatening condition with no current treatment options.
Supervised by:
Prof Cath Lawrence
Dr Paul Kasher
Prof Adrian Parry-Jones
Investigating the protective properties of angiotensin-converting enzyme inhibitors after haemorrhagic stroke
Intracerebral haemorrhage (ICH) is a catastrophic form of stroke caused by spontaneous bleeding in the brain and is a leading global cause of adult disability. There is an urgent requirement to identify widely accessible and effective acute medical treatments to reduce brain injury caused by ICH (Withers et al, 2020). Angiotensin converting enzyme inhibitors (ACE-I) are a widely used class of renin-angiotensin aldosterone system inhibitors that act as blood pressure lowering medications to prevent and/or treat cardiovascular diseases, including stroke. Although primarily used to manage hypertension, increasing evidence indicates that ACE-I may offer cellular protection via an antioxidant function (Wzgarda et al, 2017). Using an unbiased zebrafish drug screening approach, we have shown that the ACE-Is, ramipril and quinapril, significantly reduce brain cell death acutely after spontaneous brain haemorrhage (Crilly et al, 2018; Crilly et al, 2022). Furthermore, our recent unpublished work shows that acute ACE-I treatment is associated with a significant reduction in brain cell death in a mouse model of ICH. We have also shown that ACE-Is may be promising clinically. We found treatment with an ACE-I after ICH to be independently associated with better 90-day recovery in 2611 participants in the INTERACT2 clinical trial (Anderson et al, 2013; Crilly et al, 2022). Preliminary data obtained from the zebrafish ICH model indicates that acute ACE-I treatment is associated with reduced mitochondrial protein expression and decreased mitochondrial stress. Given mitochondrial dysfunction is a significant contributor to brain injury, we hypothesise that ACE-I treatment offers neuroprotection after ICH by reducing mitochondrial stress. To study this hypothesis, we will utilise a combination of zebrafish and in vitro models of ICH with live imaging, flow cytometry, transcriptomics and molecular biology to determine the mechanisms associated with ACE-I treatment and neuroprotection after ICH. This study will provide translational insight to support a role for ACE-Is in post-ICH treatment and will provide essential mechanistic information for future clinical studies.
Supervised by:
Dr Paul Kasher
Prof Adrian Parry-Jones
Prof Stuart Allan
Targeting inflammasomes to reduce inflammation in Alzheimer’s disease
Alzheimer’s disease (AD) is a devastating neurodegenerative disease for which there is no cure. Inflammation is now broadly considered to contribute to the neurodegenerative process and is considered a therapeutic target (1, 2). A component of the inflammatory response considered of importance to Alzheimer’s disease is the NLRP3 inflammasome (3).
In order to target NLRP3 effectively in AD we need to understand what cells express and activate NLRP3, and the temporal progression of its expression and activation and how this relates to disease pathology. Now, using unique tools and resources, we are in a position to address these unanswered questions.
To fully exploit NLRP3 as a therapeutic target, we need to know where it is expressed and when it is activated during the disease. The overarching aim of the proposed study is to understand the temporal and spatial expression and activation of NLRP3 and the identification of optimal therapeutic windows where it can be effectively targeted. Specific project aims are to:
1) Characterise the cellular and spatial expression of NLRP3 in the brain and vasculature in models of Alzheimer’s disease.
2) Identify NLRP3 inflammasome activation in the Alzheimer’s diseas
Supervised by:
Prof Dave Brough
Dr Roy Chun-laam Ng
Dr Kevin Couper
Microglia ferroptosis and immunometabolism in Alzheimer’s disease
APOE4 is widely recognized as a genetic risk factor for Alzheimer's disease (AD), implicated in 60-80% of all AD cases. Recent research suggests that microglia carrying the APOE4 genotype display abnormal lipid metabolism and accumulate lipid droplets, which may exacerbate the pathology of AD (1). Microglia are the resident innate immune cells of the central nervous system and undergo constant self-renewal, maintaining homeostasis throughout life. Increasing evidence suggests microglial dysfunction is involved in the pathogenesis of AD (2). Ferroptosis, an iron-induced cell death pathway, has been identified to increase lipid droplets and is linked to microglial dysfunction (3, 4). Though high iron level is found in AD brains, how APOE4 induces microglial ferroptosis in Alzheimer's disease remains unknown.
The overarching aim of this PhD study is to elucidate how APOE isoforms (APOE3, APOE4) modulate microglia functions in AD by regulating iron and lipid metabolism. Specific aims include:
Investigate the molecular mechanism of how APOE affects iron metabolism in microglia, inducing ferroptosis.
Examine how APOE4-microglial ferroptosis and functions increase AD pathology.
Characterise the link between microglia ferroptosis and lipid metabolism in APOE3 and APOE4 human AD brains.
Supervised by:
Prof Cath Lawrence
Dr Roy Chun-laam Ng
Dr Kevin Couper
Investigation of the role of smooth muscle calcium signalling in vascular dementia
Blood flow to the brain is influenced by the diameter of cerebral arterial that run along the surface of the brain (pail arteries). The arterial diameter is controlled by the membrane potential of the vascular smooth muscle cells in the arterial wall. A major ion channel that promotes a larger arterial diameter (and therefore more flow) is the large conductance Ca2+ activated K+ (BK) channel, which is activated by localised, high amplitude, transient Ca2+ release events from the sarcoplasmic reticulum called Ca2+ sparks. We have recently shown that the activation of BK channels by Ca2+ sparks is damaged in both Alzheimer’s Disease (Taylor et al., 2022) and vascular dementia (Taylor et al., 2023). However, the recording of Ca2+ sparks in the cerebral circulation in vivo has never been done before. Due to the recent advances in mouse genetics, we can spatially and temporally control genetically encoded Ca2+ indicators to record these events in vivo.
This project will use mice expressing a genetically encoded calcium indicator in the vascular smooth muscle cells. A cranial window will be inserted, and multi-photon imaging of the calcium release events will be studied on the pail arteries but also determine if these events are present in arterioles deeper in the cortex. These events will be compared to ex vivo preparations, where the pail arteries dissected out, mounted on a pressure myograph, pressurised and imaged using spinning disk confocal microscopy. Experiments will be carried out in health
Supervised by:
Dr Ingo Schiessl
Dr Harry Pritchard
Prof Stuart Allan
Prof Adam Greenstein
Understand spinal cord injuries: Developing a zebrafish model of spinal stroke
Spinal cord (SC) injuries (SCI) are devastating affecting at least 4400 people per year in the UK. It carries substantial individual and societal costs with most SCI sufferers experiencing chronic pain. Due to the lack of understanding of how SC recovers following injury no specific treatments are available to repair SCI. Therefore, there is a need to understand the mechanisms underlaying this process to improve therapies for SCI.
The injuries in the SC can result from trauma such as falls and road traffic injuries or non-traumatic causes like tumours and vascular conditions such as spinal strokes. Spinal strokes are rare, but they could be as serious as traumatic SCI. They are caused by disruption of blood supply to the SC due to a spontaneous ischaemic (Zalewski et al, 2019) or haemorrhagic event (Shaban et al, 2018). Symptomatic presentation in patients depends on the location of the infarct but can lead to severe back pain, changes in sensation, incontinence, muscle weakness and paralysis (Vuong et al, 2016).
Zebrafish is a powerful, tractable and robust animal model able to achieve functional regeneration following SCI. Elucidating the signals and mechanisms leading the successful regeneration in this model would generate valuable discoveries to be tested in higher organisms. Taking advantage of its transparency and its amenability to genetic manipulation (Soto et al, 2022) zebrafish offers a powerful approach for studying both vascular (Crilly et al, 2022) and CNS-related diseases (Tsarouchas et al, 2018). The aim of this project is to develop a zebrafish larval model of spinal cord stroke to elucidate signals and mechanisms driving spinal cord regeneration.
In this project, we will utilise transgenic fluorescent reporter zebrafish lines to study the impact of bleeding on SC degeneration and regeneration, in presence or absence of traumatic SCI. Using a laser ablation approach (Liu et al, 2016; O’Brien et al, 2009; Villegas et al, 2012), we will induce haemorrhage around the spinal cord to measure cellular outcomes. The transgenic reporter lines will allow us to use high resolution live imaging to observe spinal neurons, blood vessels, erythrocytes and immune cells, and to visualise the dynamic cellular response to spinal cord bleeding in presence of traumatic SCI in real time. We will also perform zebrafish larval swimming assays to determine the effects of spinal cord stroke on locomotion. We will aim to modify cellular and swimming outcomes through pharmacological and genetic intervention studies.
Supervised by:
Dr Paul Kasher
Dr Ximena Soto Rodriguez
Dr Karel Dorey
Using white matter network alterations relating to stroke risk to predict cognitive and health outcomes
International Partnership studentship
The project aims to investigate how age-related changes in brain white matter impact upon cognitive and health outcomes. Using advanced software and MRI data from the UK Biobank, the researchers will create effective cross-sectional and longitudinal models of how white matter abnormalities predict cognitive function. Additionally, MRI and cognitive data will be collected from adults with different stroke risks to understand how these measures change following cerebrovascular insults. This research could lead to better neurological predictions and insights into cognitive impairment mechanisms, particularly in stroke patients. The student will be able to spend six months in Bordeaux during the PhD, learning about the application of white matter neuroimaging to clinical and cognitive data from an internationally-leading research team at the Vascular Brain Health Institute.
Supervised by:
Prof Craig Smith
Dr N Muhlert
Dr William Lloyd