SYNVIVO Revealing dendritic cell-CD4+ T cell communication by using synthetic biology in vivo Project Objectives
Interactions between different cell types are key for immune function. By coupling chemical and synthetic biology with mouse genetics, our research aims at developing innovative technologies to study cell-cell communication in the immune system, and to use these novel experimental approaches to track interactions between antigenpresenting cells and T cells, with the ultimate goal of revealing the molecular pathways governing the T cell response in vivo. Confocal microscopy images of immune cells in mouse lymph node.
Characterising cell-cell interactions T-cells are an important part of the immune system, but they need to interact with dendritic cells before they can be activated and acquire specific functions. We spoke to Dr Giulia Pasqual about her research into the interactions between dendritic- and T-cells, and how this interaction influences the subsequent fate of T-cells. The nature of interactions between cells is an important topic in all areas of biology, including in the immune system. For example, T-cells must interact with dendritic cells in order to be activated, a topic that lies at the heart of Dr Giulia Pasqual’s research in the Synvivo project. “I am studying cell-cell interaction in the context of the immune system. More specifically, I am studying interactions between dendritic cells and T-cells,” she outlines. Once T-cells have been activated, they can then acquire different types of function in the immune system. “Each program secretes a defined sub-set of cytokines, some are more active in dealing with bacterial infections, while other types of T-cells can suppress or negatively regulate the immune function,” explains Dr Pasqual. “The messages that are exchanged in the context of this interaction between T-cells and dendritic cells are highly relevant in terms of the eventual fate of the T-cells.”
Synvivo project As the Principal Investigator of the Synvivo project, Dr Pasqual is working to characterise these interactions in greater depth, conducting in vivo research using mice as a model system. The focus in this research is on three specific aspects of these interactions, one of which is the identity of the dendritic cells that are involved, with researchers aiming to deconvolute the heterogeneity of the immune system. “The dendritic cell population is very heterogenous, there is a high degree of diversity within it,” says Dr Pasqual. It is difficult to study these cells using existing genetic tools, so Dr Pasqual and her colleagues are employing a new labelling technique called LIPSTIC, which helps researchers gain deeper insights than previously possible. “There are basically three components to the LIPSTIC technique. On the one side there is an enzyme, and on another cell there is a moiety that is recognised by the enzyme,” she explains. “The third component is the substrate.”
The LIPSTIC technique allows researchers to effectively attach a label to the cells involved in an interaction, such as a fluorophore or something else that can easily be detected with other reagents. One cell marks the other when they interact, and while this labelling is not permanent it does last for a few hours, providing a window of opportunity for researchers. “There is the possibility to then retrieve the cells that are involved in the interaction, and to analyse them with other methods, such as proteomics or gene expression analysis. Or we can just perform phenotyping on the cells,” says Dr Pasqual. Researchers can then compare the cells that underwent interactions with those that didn’t, and in the process learn more about the influence of those interactions on cell fate. “Using this LIPSTIC tool, or variations of it, we can map the dendritic cells that are interacting with the T-cells,” continues Dr Pasqual. A second major topic Dr Pasqual is addressing in the project is the spatial localisation of the interaction. It has been
A ligand and receptor pair involved in interaction are equipped with an enzyme and an acceptor moiety. In presence of the substrate (red kiss), and upon cell-cell interaction, the LIPSTIC reaction takes place so that one cell labels the interacting partner, which can later be identified, retrieved and analysed.
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hypothesised that the anatomical niche where an interaction takes place is highly relevant in shaping different types of T-cell response, an idea which Dr Pasqual is exploring further through in vivo research. “In order to investigate this hypothesis, we need to observe it in the natural or physiological context. When we extract cells and distribute them on a dish, we lose the complexity of different types of microanatomical niches. We want to first observe what happens in vivo, then we can use other types of tools or experimental set-ups,” she outlines. The third area of research involves performing single-cell analysis, as it’s now possible to distinguish the cells that did interact from the ones that didn’t, and then analyse them. “We’re looking at the gene expression of the different cells that were involved in interactions,” says Dr Pasqual.
the immune response, yet Dr Pasqual says there is a possible alternative approach. “A different approach could be to effectively instruct T-cells to become suppressive, to become tolerogenic,” she outlines. “It is currently challenging to tune the response in a suppressive manner.” There are tools currently available to tune the immune response in a specific direction. However, these tools are based largely on experimental evidence, and the molecular mechanism that leads to the measured effect is not always clear. “Knowing exactly what signals lead to a particular type of response would help us to rationally develop novel tools to tune the immune response,” says Dr Pasqual. The project’s work could represent an important step forward in this respect. “If, in 10 years time, we know exactly what signals are important to induce cells to be
interaction in the context of the immune system. More specifically, I am studying interactions between dendritic cells and T-cells. Once T-cells have been activated, they can then acquire different types of function in the immune system.
Project Funding
This project is funded by the European Research Council Starting Grant “Revealing dendritic cell-CD4+ T cell communication by using synthetic biology in vivo - SYNVIVO”, grant agreement 853179
Contact Details
Principal Investigator, Giulia Pasqual, Associate Professor Department Of Surgery Oncology and Gastroenterology Università degli Studi di Padova via Gattamelata 64 35128 Padova PD Italy T: +39 049 8215891 E: giulia.pasqual@unipd.it W: https://www.pasqual-lab.org/
I am studying cell-cell
Auto-immune disease The aim in this research is to describe the process that leads to T-cell activation in a more detailed way, at both the cellular and molecular level, while it also holds wider relevance in terms of the treatment of immune mediated diseases. For instance, in autoimmune diseases like multiple sclerosis (MS) and coeliac disease the immune response damages healthy cells, leading to wider health problems. “For example, in MS the T-cells recognise some components as attackers. They attack those components, and this leads to disease,” says Dr Pasqual. The majority of auto-immune diseases like MS are currently treated by broadly suppressing
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tolerogenic or suppressive, then we will have an additional tool that could be very valuable for the treatment of autoimmune diseases,” continues Dr Pasqual. This is a more general goal for researchers in the immunology field however, rather than a specific objective in Synvivo. For Dr Pasqual and her colleagues in the project, the more immediate priority is to pursue fundamental research into the interaction between dendritic cells and T-cells. “We want to more accurately describe - at both the cellular and the molecular levels - the process that leads to T-cell activation, with particular attention to both inflammatory and tolerogenic programmes,” she says.
Giulia Pasqual
Giulia Pasqual obtained a PhD in Life Sciences from the University of Lausanne, Switzerland. From 2012 to 2018 she trained as a postdoctoral fellow in immunology, first at the Massachusetts Institute of Technology and later at the Rockefeller University, USA. Since 2019 she is professor of immunology at the University of Padova, Italy.
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