Research Opportunities

In contrast to patients after myocardial infarction, fish can fully regenerate their hearts. However, not all fish are able to regenerate to the same extent, allowing comparative inter- and intra-species analysis to identify novel mechanisms controlling successful heart regeneration. We have compared the response of seven different wild type zebrafish strains as well as Astyanax mexicanus surface and cavefish to cryo-injury. Preliminary data shows that there are large differences in regeneration within each species. Using RNAseq, we have identifed OXPHOS as a crucial regulator of this difference with increased OXPHOS being beneficial to long term regeneration. This finding indicates that the current stance in the field, that OXPHOS is damaging the ability for heart regeneration, needs to be re-evaluated.

In this project, we will investigate the mechanisms underlying the beneficial role of OXPHOS during regeneration and the techniques you will perform are targeted metabolomics, QTL analysis, RNAseq and Electron Microscopy. As the human heart relies on OXPHOS for energy, the findings from this project could help identify therapies that can direct OXPHOS to enhance cardiomyocyte proliferation and harness the potential of the human heart to regenerate.

The past decade has seen the emergence of population-level magnetic resonance imaging (MRI) studies like the UK Biobank, which is scanning an unprecedented 100,000 individuals. This imaging has enormous potential to inform about early pathology or susceptibility to disease. However, to translate insights from population-level health data resources into the clinic, we require approaches to translating, or ‘harmonising’, between datasets acquired under very different conditions.

A newly funded collaboration between Oxford and the NIH aims to deliver a novel harmonisation approach by linking relevant tissue biology to the physics of the imaging measurement. Core to this ‘biophysical’ approach is a framework for predicting imaging phenotypes from multi-dimensional spectral measurements of MRI-relevant tissue properties.

This DPhil project will deliver the multi-spectral measurements at the heart of this prediction framework. The student will work within our collaborative team to:

• Year 1: implement multi-spectral acquisition protocols and associated analysis pipelines for use in a large cohort;
• Years 2-3: develop novel biophysical modelling that enables us to characterise and restrict the number of modelled tissue compartments, enabling fewer measurements for clinical scanners;
• Year 4: demonstrate the ability to predict imaging phenotypes based on these measurements in order to harmonise measurements from multiple protocols.

This project would be jointly supervised by the neuroimaging experts in Oxford who are leading brain MRI in UK Biobank (Miller) and physics experts at NIH who have pioneered these multi-spectral measurements (Benjamini).

The brain is continuously bombarded with visual input but has limited processing capacity. Learning to selectively process visual features relevant for behaviour is therefore crucial for optimal decision-making and thought to rely on activity of GABAergic inhibitory interneurons. Altered inhibition is linked to perceptual and learning impairments and associated with neurodevelopmental disorders including schizophrenia and autism.

The aim of this project is to understand the precise role of different types of GABAergic inhibitory interneurons during visually-guided learning and decision-making. Mice have a similarly organized visual cortex and show complex decision-making behaviours. Mouse brain circuits can be measured and manipulated during behaviour in ways not possible in humans.

Our approach is to train mice, including pharmacological and genetic mouse models of neurodevelopmental disorders and healthy controls, in visual decision-making tasks. We measure activity in visual cortex in specific cell types using 2-photon imaging and electrophysiology and use optogenetics to activate or inactivate activity of specific interneuron cell types. We will also apply two new innovative methods to optically measure the inhibitory neurotransmitter GABA (developed in the Looger lab, UCSD) and to locally pharmacologically manipulate GABA levels in the brain (collaboration with Malliaras and Proctor labs, Dept of Engineering, Cambridge) during visual learning and decision-making.

The PhD project is associated with a Wellcome Trust funded Collaborative programme with a cross-disciplinary international research team to investigate the role of GABAergic inhibition in both mice and humans at different scales, from local circuits to global brain networks.

Lab website: https://www.pdn.cam.ac.uk/svl
Contact: Jasper Poort jp816@cam.ac.uk

One of the major obstacles to effectively treating central nervous system (CNS) tumors is the integrity of the blood-brain barrier (BBB). The BBB prevents systemic drug delivery from reaching the brain and brain tumor tissue. While previous studies have mainly focused on circumventing the BBB, very few agents or mechanisms have been explored that modulate the tumor microenvironment to enhance effective therapies for malignant brain tumors. Our studies focus on understanding the heterogeneity of BBB permeability amongst malignant tumor cells and the role of the supportive BBB in tumor growth. Our collaborative laboratory and clinical investigations center around BBB biology, cancer biology, pharmacokinetics and pharmacodynamics related to optimal CNS drug delivery.

Using a clinical/translational approach, we aim to:

1) Evaluate the efficacy of targeted tumor and BBB directed therapy

2) Define the mechanisms that drive differences in neuropharmacokinetics of agents to the CNS

3) Identify exquisite parameters via neuro-imaging of CNS permeability amongst malignant brain tumors.

Our overall goal is to enhance our understanding of the heterogeneity of blood-brain barrier permeability among tumor cells and develop mechanism-based therapeutic interventions to treat affected brain tumor patients at the NIH Clinical Center. We use a combination of cell biology, molecular biology, imaging, pharmacokinetics and animal tumor models.

During development, brains grow rapidly as behaviors develop. Impairment in early brain development often leads to neurodevelopmental conditions, including a number of neuropsychiatric disorders. From early postnatal period throughout adulthood, learning leads to important and dynamic changes in brain circuitry, and in an animals’ behaviors to adapt and sense the environment. The hierarchical yet reciprocal interaction between thalamus and cortex is one of the key brain circuits that are involved in learning-related changes from early development to adulthood.

To investigate the development of thalamocortical connection in the context of sensory learning, this project aims to understand 1) the specificity and plasticity in the interaction between thalamus and cortex during both early development and later life, and 2) how the impairment in this functional connection during early development results in long lasting effects on the capacity for learning in the adult brain. Specifically, we will study how different neuronal types and neuromodulators play a role in the developmental and adult plasticity of thalamocortical connectivity.

To address these questions, we will use the rodent whisker-related sensory-motor system because it is ecologically relevant and critical to the animal’s abilities to navigate and engage in goal-directed behavior. We will apply a multidisciplinary approach that combines molecular and genetic techniques with in vivo intracellular and extracellular electrophysiology, in vivo longitudinal calcium imaging, viral tracing, optogenetic and pharmacogenetic methods, and quantitative behavior and anatomical analyses.

Lee’s lab at NIH will focus on early developmental studies and Bruno’s lab at Oxford will focus on adult plasticity. The two labs will use complementary approaches. A student working with Drs. Lee and Bruno will have a unique opportunity to learn conceptual perspectives from both labs, as well as a wide range of experimental and analytical methodologies in the field of system neuroscience. 

There has been increasing interest in applying computational methods in medicine, to make sense of cancer’s ‘big data’ problem by exploiting recent advances in data-processing and machine learning to capture and integrate clinical, genomic, and image data collated from hundreds of cancer patients in real-time. Such methods can be applied to digital clinical images to extract image information about patterns of pixels that are not perceivable to the human eye, allowing characterisation of tumour.  Prostate cancer is the 2nd commonest male cancer worldwide, and MRI is the diagnostic tool of choice, however, MRI can miss 10% of significant tumours and leads to unnecessary (invasive) biopsy in around 1/3rd patients who do not have cancer.  

We will use a prototype AI system (Pi) developed with Lucida Medical on retrospective data, in a prospective clinical study. We plan to link histological data to imaging features derived from MRI (including texture analysis) to identify predictors of lesion aggressiveness and need for sampling, using biopsy cores and surgical specimens from the prospective cohort. Further work will link biopsy tissue to MRI data to identify radiogenomic markers of disease aggressiveness. The project presents an opportunity for AI to answer key clinical questions at the intersection of interpretation, imaging and biopsy.  

The project will involve working with an established interdisciplinary programme of researchers and help in the assessment of cross-cutting “multi-omic” approaches to cancer assessment, involving integration of advanced image analysis, transcriptomic, genomic, tissue, and patient outcomes to inform the design of diagnostic strategies.

We are developing artificial multi-valent proteins capable of liquid-liquid phase separation (LLPS) with the aim of building multi-functional biomolecular condensates and thereby harnessing specific cellular enzymes to target disease-associated proteins for destruction. We propose to design condensates that contain a class of proteins known as tandem-repeat proteins (RPs). We have shown that RPs are strikingly amenable to rational design and can be engineered to simultaneously bind multiple proteins, bringing them into specific spatial proximity in such a way as to enable a chemical modification of the target protein. The rational design of LLPS systems capable of selectively recruiting client proteins into them to drive specific biological reactions would enable both a deeper understanding of the role of biomolecular condensates in nature as well as the exploitation of their remarkable physico-chemical properties for therapeutic effect. 

Key areas of interest include: 
 

1. Understanding the molecular grammar of protein phase separation to define rules for creating designer LLPS systems. 

2. Developing novel hetero-bifunctional phase-separating proteins to recruit disease-associated targets to the protein degradation machinery. 

3. Translating the designed LLPS proteins into biomolecular condensates in the cell capable of enhancing targeted protein degradation. 

“Life will find a way….” In a now famous quote from the 1993 movie Jurassic Park, the “chaotician” Ian Malcolm nicely captures the essence of adaptation through evolution. But series evolutionary change often requires multiple mutations to arise – the changes arising from SNPs and indels in single genes usually amount to little more than phenotypic “tinkering”. So what would happen if we could “step on the evolutionary gas pedal” and accelerate the pace of change? Or alternatively, what would be the consequences of “slamming on the evolutionary brakes” to prevent adaptation? Well, these are just the kind of approaches that we have developed in the Welch lab, and we are applying these to look at how the opportunistic bacterial pathogen, Pseudomonas aeruginosa, adapts to the presence of infection-relevant selection pressures. Essentially, we’ve engineered the mismatch-repair system to come under the control of an inert chemical inducer, and so can “rheostatically” modulate the rate of mutation from very high (1000 x the wild-type level) to very low indeed (eliciting a state of “hypomutation” in which evolutionary change essentially grinds to a halt).

Using this system, we aim to investigate the evolutionary trajectories of P. aeruginosa when challenged with intense selection pressures e.g., in a polymicrobial environment, or upon exposure to antimicrobial agents or nutrient limitation. Project will involve elements of synthetic biology, microbiology, evolutionary biology, modelling and genomics. A stable polymicrobial culture system has recently been developed by the lab and is available for use.  

Accumulation of vascular smooth muscle cells (VSMCs) is a hallmark of cardiovascular diseases such as atherosclerosis, which cause heart attack and stroke. In healthy vessels, VSMC contraction regulate blood flow and blood pressure but loose their contractile function and undergo extensive transformation upon vasuclar insult. This process results in the generation of a wide spectrum of phenotypically changed cells within atherosclerotic lesions, which are predicted to impact differently on disease progression. Using clonal lineage tracing in mouse models of atherosclerosis, we demonstrated that disease-associated cell accumulation result from extensive proliferation of a small subset of VSMC that can generate the full range of distinct cells. By combining lineage tracing with single cell RNA sequencing (sc-RNAseq) in mouse models, we have identified signatures of VSMC-derived cells subpopulations. Interestingly, cells displaying mesenchymal stem cell character are rare in healthy vessels and their numbers increase in disease models. The aim of this project is to understand how specific VSMC-derived cell populations in human disease arise, using a combination of genomics and functional assays, in order to allow efficient cell targeting in atherosclerotic lesions.

The human placenta is the first organ of the embryo and it is functional immediately after implantation. Before fetal organogenesis, the placenta holds a multi-functional and unique role as a physical, chemical, and cellular barrier. It alone orchestrates the chemical communication between mother and fetus. Most of this communication is mediated by the secretion of specific placental peptide hormones (hCG, hPL, etc.) into the maternal bloodstream. Despite these hormones having developmental and irreplaceable functions, little is known about their intracellular life: synthesis, intracellular traffic, secretion, and degradation. More importantly, many pregnancy disorders are associated with lower expression and levels of these hormones in circulation, such as fetal growth restriction and preterm birth. The cell biology of these diseases is not well understood.

With the recent advance in human placenta organoid development and novel culture techniques of trophoblasts derived from stem cells, we can now finally interrogate the fundamental questions about placental hormones' intra and extra-cellular fate. In combination with the diverse set of advanced imagining methods available between the co-mentors of this project (advanced fluorescence and cryo-electron microscopy), innovative multi-omics techniques, and advanced biochemistry and cell biology approaches, we propose to 1) discover the diversity of secretory granules (SGs) expressed in and secreted from the human placenta; 2) implement a novel in vitro secretomics approach to determine the molecular machinery that regulates the secretion of the SGs and their content; 3) validate the mechanisms using human placenta and isolated trophoblasts from donated tissue and new placenta organoids culture.

The successful candidate will have the opportunity to train on several modern imaging techniques and learn about the fundamentals of placenta development and physiology while using a multi-disciplinary approach in a team of expert cell biologists from both institutions and generating impactful basic and applied research.

Maternal over-nutrition and obesity during pregnancy is known to have long-term effects on the health of the offspring, including increased risk of obesity. Weight gain in offspring exposed to maternal over-nutrition is at least in part caused by hyperphagia- implicating altered function of hypothalamic energy homeostatic pathways as an underlying cause- but the precise mechanisms by which the in utero environment impacts on hypothalamic development is unclear. Key metabolic hormones such as insulin, leptin and ghrelin have a dual role during brain development as growth factors. These metabolic hormones are altered in an obese pregnancy, providing a direct route by which the maternal nutritional state can impact on offspring hypothalamic development. We will use a combination of in vivo manipulation of hormone levels (e.g. fetal brain injection) and ex vivo neuro-developmental techniques (e.g. neurospheres) to examine the consequences of altered metabolic hormone levels for early hypothalamic development. We will also use immunofluorescence and viral tracing to study hypothalamic architecture in the offspring of obese mothers once they reach adulthood, and correlate the anatomy with functional readouts of complex feeding behaviours using operant and metabolic chambers.

Mitochondrial diseases are caused by defects in genes required for energy production and oxidative phosphorylation (OxPhos). We find it intriguing that some patients with mitochondrial disease present late in life, with very tissue-specific phenotypes. It seems that not all cells and tissues are equally susceptible to mitochondrial disease.

We mainly study how mitochondrial dysfunction and mutations in the mitochondrial genome affect neural stem cell behaviour in Drosophila and mouse. The questions we address are:
(1) how mitochondrial dysfunction affects normal and pathological cell fate decisions in the developing brain. We previously showed that neural stem cells in the brain rely heavily on mitochondrial energy production and now study how they interact with the glial cells that make up their stem cell niche.
(2) how transcription of the nuclear genome is regulated when a cell is confronted with mitochondrial dysfunction. We employ and develop innovative DamID-based in vivo chromatin profiling technology to study metabolism of chromatin modification.
(3) how mutations in the mitochondrial genome evolve over time, during brain development and aging. We use in situ hybridisation-based methods and single-cell CRISPR screening to identify novel regulators of mitochondrial genome maintenance.

In order to study these questions in an in vivo context, in (stem) cells surrounded by their appropriate tissue environment, our primary model system is the fruit fly, Drosophila melanogaster. In addition, we actively translate our findings and the technology we develop into mammalian model systems, in particular the mouse embryonic cortex.

Relevant references
- van den Ameele J, Krautz R, Cheetham SW, et al., Reduced chromatin accessibility correlates with resistance to Notch activation. Nat Commun. 2022;13(1):2210.
- van den Ameele J, Li AYZ, Ma H, Chinnery PF. Mitochondrial heteroplasmy beyond the oocyte bottleneck. Semin Cell Dev Biol. 2020 Jan. 97:156-66.
- van den Ameele J, Brand AH. Neural stem cell temporal patterning and brain tumour growth rely on oxidative phosphorylation. eLife. 2019;8:e47887.
- Tiberi L*, van den Ameele J*, Dimidschstein J, Piccirilli J, Gall D, Herpoel A, Bilheu A, Bonnefont J, Iacovino M, Kyba M, Bouschet T, Vanderhaeghen P. Bcl6 induces neurogenesis through Sirt1-dependent epigenetic repression of selective Notch targets. Nat Neurosci. 2012 Dec;15(12):1627-35.
- Gaspard N, Bouschet T, Hourez R, Dimidschstein J, Naeije G, van den Ameele J, Espuny-Camacho I, Herpoel A, Passante L, Schiffmann SN, Gaillard A, Vanderhaeghen P. An intrinsic mechanism of corticogenesis from embryonic stem cells. Nature. 2008 Sep 18;455(7211):351-7.

The presence and role of neural stem cells (NSCs) in the adult human brain is a long-debated issue in neuroscience. Recent work has demonstrated that stem-like cells exist in the embryonic, foetal, and human adult brain where they persist well into adulthood and can even contribute to neurogenesis. However, their role in neurodegenerative disease is unknown. Ongoing work in the lab has led to the hypothesis that NSCs may become dysfunctional in neurodegenerative disease resulting in senescence chronic inflammation, and thereby acting as pacemaker cells driving neuronal demise. This ambitious project aims to identify disease-associated NSCs and their phenotype in the context of human neurodegeneration using spatial biology approaches, including imaging mass cytometry, RNA scope and single nuclear RNA sequencing. Relying on post-mortem brain tissue of different stages of Alzheimer’s disease, traumatic brain injury, vascular dementia and chronic stroke, this project will study NSCs in a range of human diseases characterised by neurodegeneration and neuronal injury. Ongoing work in the lab identifies NSC-specific markers based on transcriptomics and protein profiling experiments in brains with progressive multiple sclerosis, enabling to investigate the distribution of NSCs in a wide range of diseases. Spatial transcriptomics and proteomic approaches will allow to study their phenotype and dysfunction in relation to other cell types and local pathology. This project will shed light on the role of NSCs in neurodegeneration and has the potential to identify an entirely novel mechanism of neurodegeneration in human disease.

This project will be co-supervised by Prof. A. Quaegebeur.

Multipotent self-renewing hematopoietic stem cells (HSCs) support life-long blood system homeostasis and play essential roles in human disease and its therapy. HSC transplantation is an important cell therapy for a range of hematological diseases including immunodeficiencies, beta-globinopathies, and blood cancers. Through their ability for self-renewal and multipotency, HSCs can reconstitute the hematopoietic system following transplantation. Most HSC transplants are performed using allogeneic HSCs but there is also a growing interest in the development and use of autologous HSC transplantation gene therapies for a range of non-malignant blood diseases. A major unresolved question in the field is what regulates the fitness of an HSC. High fitness HSCs display durable and balanced blood system reconstitution activities. By contrast, low fitness HSCs have weak or biased activities. The accumulation of low fitness HSCs is thought to contribute to various disease pathologies and their use in HSC transplantation can result in engraftment failure. Building on research interests in the Muljo lab at the NIH and the Wilkinson lab at the University of Oxford, this project will focus on characterizing transcriptional and post-transcriptional mechanisms regulating HSC fitness. Biological mechanisms identified here will be used to devise new strategies to enhance life-long hematopoietic system health and to improve the safety and efficacy of HSC transplantation therapies.
 

Recent publications:

Wang, S., Chim, B., Su, Y., Khil, P., Wong, M., Wang, X., Foroushani, A., Smith, P. T., Liu, X., Li, R., Ganesan, S., Kanellopoulou, C., Hafner, M. and S. A. Muljo. Enhancement of LIN28B-induced hematopoietic reprogramming by IGF2BP3. Genes & Development, 33: 1048–1068. DOI: 10.1101/gad.325100.119.

Wilkinson, A.C., Ishida, R., Kikuchi, M., Sudo, K., Morita, M., Crisostomo, R.V., Yamamoto, R., Loh, K.M., Nakamura, Y., Watanabe, M., Nakauchi, H. and S. Yamazaki. (2019). Long-term ex vivo haematopoietic-stem-cell expansion allows nonconditioned transplantation. Nature, 571: 117–121. DOI: 10.1038/s41586-019-1244-x.

Haney, M.S., Shankar, A., Hsu, I., Miyauchi, M., Palovics, R., Khoo, H.M., Igarashi, K.J., Bhadury, J., Munson, C., Mack, P.K., Tan, T., Wyss-Coray, T., Nakauchi, H., Wilkinson, A.C. Large-scale in vivo CRISPR screens identify SAGA complex members as a key regulators of HSC lineage commitment and aging. bioRxiv 2022. DOI: 10.1101/2022.07.22.501030

Immunity and immune-tolerance at mucosal and other barrier surfaces is vital for host survival and homeostasis with antibodies or immunoglobulins (Ig) playing a key role. However, the specific roles of B cell sub-types, particularly, the innate-like B-1 cell subset is poorly understood. The surgeon James Rutherford Morrison (1906) called the omentum in the peritoneal cavity the "abdominal policeman" and it promotes gut IgA production by peritoneal B-1 cells. IgA is the most abundantly produced antibody isotype and is known to be important for mucosal immunity. It is estimated that ~50% of IgA is derived from B-1 cells. In addition, B-1 cells are thought to be important because they make T cell-independent “natural” IgM circulating in our blood, and they can rapidly respond to mucosal perturbations such as an infection. By contrast, it will take conventional B-2 cells weeks to mount a germinal center (GC) reaction and generate antibodies that have undergone T cell-dependent affinity maturation and isotype switching. Textbooks currently do not entertain the possibility that B-1 cells can also participate in GC reactions. This project aims to challenge such an assumption. After all, B-1 cells in the gut mucosa and probably other mucosal tissues can undergo class switch recombination to IgA. However, the differentiation program that leads to this distinct pathway of IgA production is not well understood: for example, it is unknown if this process occurs outside or within GCs in mucosa-associated lymphoid tissues (MALT). Expertise on B-1 cells in the Muljo lab and the GC reaction in the Turner lab will be combined to explore this potentially paradigm-shifting research. Both wet-bench and bioinformatic research opportunities are available.

Students will learn about the fundamentals of transcriptional; epigenetic and post-transcriptional regulation; immunometabolism; in vivo CRISPR screening; CRISPR editing in primary B cells; and systems immunology. The combination of classical immunological techniques and cutting-edge, multi-disciplinary approaches will enable important discoveries to define the in vivo biology of B-1 cells. Ultimately, we seek novel insights that can be translated to inform vaccine design targeted to activate B-1 cells and/or therapeutics to inhibit their activity when necessary.
 

Recent publications:

Turner, D. J., Saveliev, A., Salerno, F., Matheson, L. S., Screen, M., Lawson, H., Wotherspoon, D., Kranc, K. R., and Turner, M. (2022). A functional screen of RNA binding proteins identifies genes that promote or limit the accumulation of CD138+ plasma cells. eLife, 11, e72313. PMID: 35451955; DOI: 10.7554/eLife.72313.

Osma-Garcia, I.C., Capitan-Sobrino, D., Mouysset, M., Bell, S.E., Lebeurrier, M., Turner, M. and Diaz-Muñoz, M.D. (2021). The RNA-binding protein HuR is required for maintenance of the germinal centre response. Nature Communications, 12(1):6556. PMID: 34772950; DOI: 10.1038/s41467-021-26908-2.

Wang, S., Chim, B., Su, Y., Khil, P., Wong, M., Wang, X., Foroushani, A., Smith, P. T., Liu, X., Li, R., Ganesan, S., Kanellopoulou, C., Hafner, M. and S. A. Muljo. (2109). Enhancement of LIN28B-induced hematopoietic reprogramming by IGF2BP3. Genes & Development, 33: 1048-1068. PMID: 31221665; DOI: 10.1101/gad.325100.119.