3rd Student Cohort

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) affecting more than two million people worldwide. The exact pathomechanisms have remained unclear and the disease is not curable to date. The histopathology of MS is characterized by inflammation, demyelination and axonal damage. Patients typically present with a wide and heterogeneous range of symptoms depending on the lesion localization, including visual, sensory, motor and cognitive deficits. Interestingly, about two thirds of patients also show gastrointestinal dysfunction, frequently even before the onset of CNS symptoms. We have previously demonstrated the degeneration of the enteric nervous system (ENS) in experimental autoimmune encephalomyelitis (EAE), which is the most common mouse model of MS. Besides the ENS the gut wall also contains several populations of immune cells, among them are the so-called muscularis macrophages that may play an important role in mediating local immune responses. It was recently shown that this population has anti-inflammatory properties and our initial data suggest that these macrophages express casein. So far, there are no studies that further elucidate the role of muscularis macrophages in the context of MS and in relation to ENS pathology. The aim of this project is to perform an in-depth immunological characterization of casein-expressing muscularis macrophages and to identify their functional role in the generation of local immune responses. To this end, a wide range of clinical-physiological, molecular and histological methods will be employed. Using established protocols of the Kürten lab in Bonn, we will induce EAE in wild-type and casein-deficient mice to analyze the function of muscularis macrophages in this particular neuroinflammatory environment compared to homeostasis. With results obtained during the first year in Bonn, we will use the expertise of the Furness lab in Melbourne to investigate ENS function both on the clinical and physiological level in casein-deficient healthy and EAE mice, which will be complemented by histological measurements performed in Bonn. 

Disorders of the digestive system are prevalent in a wide number of neurological disorders including multiple sclerosis (MS), Parkinson’s disease, spinal cord injury (SCI), amyotrophic lateral sclerosis, Huntington’s disease (HD), prion diseases, presenile dementia and Alzheimer’s disease. This project will mostly focus on effects on the enteric nervous system (ENS) and intestinal motility in MS. MS is an autoimmune and neurodegenerative disorder that targets the central nervous system (CNS). People with MS can exhibit GI dysfunction at some point or throughout the disease progress. Constipation is more prevalent in MS (67-69%) than the general population (2-20%) which, including the economic and social impact, affects the quality of life in MS patients. The neurobiological mechanism of bowel dysfunction in MS is not understood. Better understanding may lead to the development of a therapy. Amongst the reasons for constipation in MS might be 1) Demyelinating inflammatory lesions in the CNS could possibly affect the central autonomic pathways that control bowel function; 2) Degeneration or damage to the neurons in the ENS that control bowel function could be caused by an auto-immune reaction of these neurons.
Experimental autoimmune encephalomyelitis (EAE), an auto-immune-induced animal model for MS, is useful for studying the overall inflammation of the CNS and the tissue injury caused by the inflammation. EAE would be appropriate to study effects on the ENS and bowel function, because recent publications revealed that EAE mice exhibit bowel dysfunction, antibody mediated gliosis and death of ENS neurons.
This project uses Prof. Kuerten’s expertise on MS and Prof Furness’s expertise on neurogastroenterology to investigate the extent to which EAE mice exhibit bowel dysfunction and identify the neurobiological basis of the disease processes underlying bowel dysfunction.

Human pathogenic viruses present an ongoing global public health problem highlighted by continuing endemic infections and seasonal epidemics, as well as pandemics caused by newly emerging viruses. While host proteins play specific roles in normal cellular function, some of these proteins also display antiviral activity, and are termed host restriction factors. Host restriction factors can inhibit the infection and replication of different viruses at distinct stages in the viral life cycle. In general, the expression of host restriction factors during viral infection occurs following sensing of common pathogenic components via pattern recognition receptors (PRRs) and the production of type I interferons (IFNs). IFNs, in turn, activate hundreds of interferon-stimulated genes (ISGs) resulting in the inhibition of specific viruses, and some ISGs display a broad antiviral activity. SAM domain and HD domain-containing protein 1 (SAMHD1) is an intracellular dNTP triphosphohydrolase (dNTPase), while membrane-associated RING-CH-type finger protein 8 (MARCH8) is a family member of the RING-type E3 ubiquitin ligases expressed on the cell surface. This project studies molecular pathways to understand how intracellular host factors, SAMHD1 and MARCH8, restrict the infection and replication of different RNA and DNA viruses. Research in the Reading Laboratory in Melbourne focuses on the ability of these host factors to mediate direct antiviral activity against a range of human RNA and DNA viruses, including influenza A virus, respiratory syncytial virus, herpes simplex virus and vaccinia virus. Research in the Bartok Laboratory in Bonn focuses on the ability of SAMHD1 and MARCH8 to mediate indirect antiviral activity through the modulation of type I IFN signalling and ISG induction. Overall, this project aims to identify and characterise host restriction factors with novel antiviral activity against one or more human viruses, which might represent targets for the development of broad-acting antiviral therapies in the future.

Malignant melanoma is an aggressive type of skin cancer that has the ability to metastasize to surrounding organs, rendering standard therapies ineffective. The emergence of tumor escape mechanisms in response to the microenvironment allows for tumor plasticity and tumor resistance causing limitations to treatment options. One such mechanism is phenotype switching where melanoma cells could switch between a differentiated and a de-differentiated phenotype, thereby altering the expression of specific melanocytic differentiating markers and escaping immune surveillance. Using Hölzel’s expertise in molecular and tumor biology, a B16 melanoma model would be generated featuring different phenotypic characteristics to study the effect of these phenotypic differences on immune cell phenotype via in-vitro and in-vivo approaches. Once validated, the model could be studied in-vivo to track tumor development and metastasis to the lymph node via an epicutaneous model generated in Gebhardt’s lab using different complex imaging techniques. This would allow us to study the interaction between the immune cells and melanoma cells in-vivo. In addition, it would be of interest to study human primary melanoma models by analyzing lymph node sentinels containing primary tumor lesions and analyzing their phenotype in parallel with immune cells to examine the spatial interaction, heterogeneity, and frequency at a single level using a highly multiplexed imaging technique to characterize multiple markers at the same time. Thus, by deciphering the role of melanoma phenotype on immune cell surveillance and metastasis, a better understanding could be achieved in characterizing the cell dynamics, the tumor microenvironment, therapy resistance mechanisms, and biomarkers involved in the immune-mediated control of melanoma.

Metastatic disease is the major cause for cancer-related mortality. Metastatic spread and outgrowth are accompanied by dynamic changes in the interactions between cancer and immune cells with key aspects of this crosstalk likely to depend on disease stage and the type of organ affected. The Gebhardt laboratory has recently developed a preclinical melanoma model that allows to study immune control of metastatic melanoma following curative-intent surgery of primary tumours. As part of previous joined PhD projects, the Hölzel laboratory has generated and contributed numerous genetically modified melanoma lines to the model. These cell lines are now routinely used in the Gebhardt laboratory and have been integral in generating the preliminary data that the aims of the PhD project are now following up on. More specifically, the project will investigate the functional significance of melanoma cell expression of MHC II in lymphoid metastases. In addition, the project will seek to be better understand how immune pressure impacts on the route of metastatic dissemination from primary tumours, as well as on the clonal composition of metastatic deposits in different organs. Work with the in vivo model will be conducted in the Gebhardt laboratory where all required methodologies are already established (e.g. high dimensional flow cytometry, multiphoton and bioluminescence imaging, histology). Generation of new melanoma lines and high dimensional imaging of samples shipped from Melbourne will be conducted in the Hölzel where these techniques are used routinely.

Despite vaccination and antibiotics, infections leading to pulmonary damage and pneumonia are amongst the top four killers worldwide. Although much is known about the role of innate and adaptive immunity in fighting pneumonia, much less is known about regulatory circuits controlling the activity of immune cells resulting in pathogen clearance. We aim at untangling these interactions by combining the long-standing expertise on cellular immunity, lung infections and microbiology in the laboratories of the Bonn and Melbourne supervisors. Recently, we have identified a novel cross-talk between lung epithelial cells and neutrophils resulting in increased bactericidal activity of the later and accelerated pathogen clearance. In this funding period, we want to extend on those finding to understand the precise cellular and molecular interactions in this stroma-immune cell crosstalk. For this, we will employ state-of-the-art technologies such as single-cell mRNA sequencing, advance imaging, high-dimensional flow cytometry, proteomics, metabolomics, genetically-modified models, organoid cultures and diverse cellular assays. This project will provide fundamental insight to understand immunity against bacterial and viral lung pathogens that may provide the basis for novel therapies in human pneumonia.

Dendritic cells (DCs) are antigen-presenting cells that act at the interface between innate and adaptive immunity. Heterogeneity and plasticity of DCs differ in lymphoid and non-lymphoid tissues. The ability of DCs to migrate and transport peripherally ingested antigens to draining lymph nodes for T cell priming is essential for inflammation and immunity. Chemotaxis and migration of DCs are driven by chemokine-receptor interaction and regulated in a tissue-specific manner by intracellular mechanisms such as cytoskeletal remodeling. Novel strategies targeting DC motility are needed for the treatment of inflammatory and infectious diseases and for the development of new DC-based vaccines. Recent studies have shown that imaging in combination with pooled genetic perturbations using CRISPR-based system underlying fundamental and disease-related processes have resulted in phenotypic measurements with high spatial, temporal, and molecular resolution. In this project, we propose to combine Prof Waldemar Kolanus' expertise in imaging chemokine-driven dendritic cell motility with Prof Justine Mintern's expertise in unique genetic screening to understand how chemokine-driven dendritic cell migration is regulated. Through unique genetic screening, we will identify the molecular pathways that control dendritic cell migration. We will monitor the detailed parameters of dendritic cell migration in real time using advanced imaging technology.
We will investigate how dendritic cells motilities and present antigens for T cell priming, which signaling molecules/pathways regulate dendritic cell polarization, motility and alter their interaction with other immune cells. Finally, we might combine the project with in vivo studies on vaccination and immunotherapy.

Dendritic cells are critical to the initiation of an immune response. While sparse in tissues, dendritic cells possess a remarkable and unrivalled capacity to stimulate T cells upon arrival to lymphoid tissue. This ability will be exploited throughout the project, to reveal new cellular mechanisms in dendritic cells which can possibly foster new immunotherapies, driven by dendritic cells to fight cancer. The first phase of the project will take place in the Mintern Lab in Melbourne. The Mintern lab has developed a novel technique for way genetic screens utilizing CRISPR/Cas9 to identify new molecular pathways in dendritic cells. Pathways on interest includes those who is affected by the expression of Flt3, some of these being transcription factors. Hereafter, the validated gene pathways will be targeted in mouse models of vaccination and immunotherapy. This will allow us to verify the importance of these pathways in relation to other immunological and physiological functions. The final part of the project will take place within the Paeschke lab in Bonn, where the expertise lies within techniques for determining molecular mechanisms in dendritic cells. The work planned to be carried out will include, but not be limited to knock out cell models, RNA sequencing and binding assays all utilizing cell cultures to determine the modes of action for the Flt3 related transcription factors and to some extend the effect of G-quadruplex formation in dendritic cells.

The symbiotic interactions between a host and its associated microbiome are pivotal in many physiological processes, particularly in the development and maintenance of immune cells.
Evidence from the Bedoui laboratory points towards microbiome-derived signals driving at least some parts of these host-microbiome interaction. Butyrate, a metabolite derived from the gut microbiome was shown to direct CD8 “killer” T cells to a more memory like phenotype. However, the nature of these metabolites and their underlying mechanisms by which they influence CD8 T cells remain relatively uncharacterised. Additionally, other forms of microbiota-immune cell interactions are likely to influence the phenotype of CD8 T cells. In this project, these mechanisms will be investigated utilising various techniques such as the multiplex imaging expertise of Michael Hölzel, high dimensional flow cytometry, and 16S rRNA sequencing for microbiota characterisation. Furthermore, these mechanisms will be examined in various disease contexts with the aim of discovering molecular pathways that can be targeted to reduce overall disease burden.