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Dissecting immune interactions in health and disease with multiomics and spatial technologies


Type

Thesis

Change log

Authors

Arutyunyan, Anna 

Abstract

Cells are the basic building blocks of life, forming the enormous plethora of tissues and living organisms on Earth. They have a high diversity of phenotypes and functions in different environments. The high-throughput tools to profile different modalities from a single cell have grown exponentially in recent years. This now allows us to draw a complete picture of how cells function in different environments for the first time. In the work of my thesis, I use high-throughput multiomics and spatial technologies to create comprehensive cell atlases. I focus on studying the immune cell communication among themselves and with other cells in the context of disease and development.

Chapter 1 starts with an outline of the background on cell biology and the impact that genomic technologies have on how we can study cellular processes. I then discuss the experimental methodology of high-throughput multiomics and spatial techniques, and computational tools for the analysis of such data. Following is the introduction to the two projects comprising the work of my thesis: (i) a multiomics study of Common Variable Immunodeficiency (CVID) and, (ii) a spatial multiomics map of the Maternal-Fetal Interface (MFI) in early pregnancy in humans.

Chapter 2 outlines materials and methods used in this work, showcasing the workflow for each project.

Chapter 3 details the multiomics atlas of Common Variable Immunodeficiency (CVID). This condition is characterised by defects in the function of B cells, a type of adaptive immune cells capable of producing antibodies to fight infections. I analyse gene expression and chromatin accessibility data of B cells from a pair of monozygotic CVID-discordant twins. I uncover potential defects in the epigenome of the affected twin’s B cells. Next, after in vitro stimulation of these twins’ PBMCs, I observe CVID-associated transcriptional dysregulation in immune subsets additional to those in B cells. I discover defects in the immune cell crosstalk between B cells and other immune compartments of the CVID twin. With an expanded cohort of CVID patients and healthy individuals, I go on to further validate these findings. These results show that, in addition to B-cell-intrinsic alterations, defects in cell-cell communication between B cells and other immune compartments may be compromising the correct immune response in CVID.

Chapter 4 presents the work on creating a comprehensive spatial multiomics atlas of the maternal-fetal interface in early pregnancy. Firstly, I characterise the signatures and differentiation trajectories of trophoblast cells - the building blocks of placenta. I then focus on the crosstalk between invading trophoblast and maternal immune cells. I predict putative cell-cell communication events and validate in situ the selected molecules mediating these interactions. I propose a model of arterial transformation facilitated by fetal trophoblast and their communication with maternal cells. This work expands our knowledge about the cellular and molecular players in the maternal-fetal dialog in the first trimester of pregnancy, definitive of its success.

Chapter 5 describes the work on modelling the dialog between decidual natural killer (dNK) cells, a type of innate immune cell most abundant in pregnant decidua, and the invading trophoblast at the maternal-fetal interface using primary trophoblast organoids (PTO). I benchmark the PTO system against the in vivo trophoblast atlas I described in chapter 4. After defining trophoblast cell states in vitro, I perform comparative analysis of PTOs stimulated with a cocktail of chemokines that in vivo are secreted by dNK cells and unstimulated PTOs as control. I propose a putative effect of the signals from dNK cells on trophoblast invasion in the first trimester of pregnancy.

Lastly, Chapter 6 provides an overview of all the described work, as well as a discussion of how the novel high-throughput multiomic and spatial technologies together with in vitro models shape our current view of fundamental biology, and how they will impact future directions of research.

Description

Date

2023-09-01

Advisors

Vento-Tormo, Roser

Keywords

Cell-cell communication, CVID, Maternal-fetal interface, Single-cell genomics

Qualification

Doctor of Philosophy (PhD)

Awarding Institution

University of Cambridge
Sponsorship
Wellcome Trust 4-Year PhD Studentship
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