Periodic Reporting for period 3 - MiniEmbryoBlueprint (The mammalian body plan blueprint, an in vitro approach)
Reporting period: 2022-08-01 to 2024-01-31
The main objective of the project is to understand the interplay between mechanical and chemical signalling in the emergence and elaboration of the mammalian body plan. The question responds to two facts. The first one, that
much of our understanding of animal development is based around the structure and function of genes and their organisation into Gene Regulatory Networks. In this view, cells are direct products of genes. However, over the last ten years it has become clear that cells, and in particular ensembles of cells, have an important say in gene activity. Specifically, multicellular ensembles, their geometry and the forces that their interactions generate, play a role in the organization of the activity of the Gene Regulatory Networks. At the moment we know very little about this interplay and to fill this gap is the main motivation for the project. Furthermore, my group has developed a new Embryonic Stem (ES) cell based model of early mammalian development that we call 'the gastruloid'. Gastruloids are aggregates of ES cells that, under culture conditions that we specify, undergo events that mimic the process of gastrulation (hence their name) and generate structures with the hallmarks of the mammalian body plan. They have primordia for the different organs and tissues correctly allocated in space relative to each other. We have shown that both, in terms of gene expression and spatial organisation, gastruloids imitate embryos. However, and surprisingly, they lack much of the morphogenesis i.e the organization of tissues into specific cellular architectures. Using this surprising feature we have shown that introducing mechanical constrains in the gastruloids, we can elicit some morphogenesis. This observation has proved the point that they can be used to address the main aim of the project, namely how multicellular spatial constrains affect and organize gene activity and, at large, the relationship between genes and cells in development.
There are two significant societal impacts of the work. The first one is the opportunity to learn about how cells control gene activity and thus, slowly, change the current 'gene-centric' view into a more global understanding of embryos and organisms from the perspective of cells. The second one is the further development of the gastruloid system as an experimental system that can, dramatically, reduce the use of animals in research. At this, the system has a strong impact on the 3Rs (Replacement, Reduction and Refinement) in the use of animals in research. Most significantly, we have shown that we can obtain gastruloids from human ES cells and this has opened up an avenue to explore the early stages of human development, something that has remained impossible to do. This is turn will allow disease modelling of multiple neonatal conditions. An important aspect of gastruloids is the fact that they are compliant with all ethical rules of research with human embryos. The project does not include working with human gastruloids but an request has been made to do this on the grounds of the significance and potential of the research.
much of our understanding of animal development is based around the structure and function of genes and their organisation into Gene Regulatory Networks. In this view, cells are direct products of genes. However, over the last ten years it has become clear that cells, and in particular ensembles of cells, have an important say in gene activity. Specifically, multicellular ensembles, their geometry and the forces that their interactions generate, play a role in the organization of the activity of the Gene Regulatory Networks. At the moment we know very little about this interplay and to fill this gap is the main motivation for the project. Furthermore, my group has developed a new Embryonic Stem (ES) cell based model of early mammalian development that we call 'the gastruloid'. Gastruloids are aggregates of ES cells that, under culture conditions that we specify, undergo events that mimic the process of gastrulation (hence their name) and generate structures with the hallmarks of the mammalian body plan. They have primordia for the different organs and tissues correctly allocated in space relative to each other. We have shown that both, in terms of gene expression and spatial organisation, gastruloids imitate embryos. However, and surprisingly, they lack much of the morphogenesis i.e the organization of tissues into specific cellular architectures. Using this surprising feature we have shown that introducing mechanical constrains in the gastruloids, we can elicit some morphogenesis. This observation has proved the point that they can be used to address the main aim of the project, namely how multicellular spatial constrains affect and organize gene activity and, at large, the relationship between genes and cells in development.
There are two significant societal impacts of the work. The first one is the opportunity to learn about how cells control gene activity and thus, slowly, change the current 'gene-centric' view into a more global understanding of embryos and organisms from the perspective of cells. The second one is the further development of the gastruloid system as an experimental system that can, dramatically, reduce the use of animals in research. At this, the system has a strong impact on the 3Rs (Replacement, Reduction and Refinement) in the use of animals in research. Most significantly, we have shown that we can obtain gastruloids from human ES cells and this has opened up an avenue to explore the early stages of human development, something that has remained impossible to do. This is turn will allow disease modelling of multiple neonatal conditions. An important aspect of gastruloids is the fact that they are compliant with all ethical rules of research with human embryos. The project does not include working with human gastruloids but an request has been made to do this on the grounds of the significance and potential of the research.
An important property of gastruloids is their ability to self organise interactions between derivatives of different germ layers that can result in the assembly of complex primordia and structure e.g early cardiac structures. Investigating the role of signalling in early patterning events, we noticed the emergence of structures associated with hematopoiesis. Pursuing these structures, we have observed that gastruloids can organise a hematopoietic stem cell niche like structure that produced pre-hematopoietic stem cells. We are pursuing this at the moment as, if and when transferred to human gastruloids, it might provide a source of hematopoietic stem cells that in the long term can have therapeutic potential.
Due to the pandemic and my move to Barcelona, progress has been slow but the project is now on track to yield results and insights. We have established microscopy and computational technology that will allow us to track cells at high resolution and provide with insights about the role that mechanochemical signalling plays in the early stages of mammalian development. To this end we are also developing powerful single cell reporters of signalling, in particular Wnt, Nodal and FGF.
Due to the pandemic and my move to Barcelona, progress has been slow but the project is now on track to yield results and insights. We have established microscopy and computational technology that will allow us to track cells at high resolution and provide with insights about the role that mechanochemical signalling plays in the early stages of mammalian development. To this end we are also developing powerful single cell reporters of signalling, in particular Wnt, Nodal and FGF.
The project has now in place a state of the art Light sheet microscope and associated computational infrastructure to allow us high resolution visualisation and tracking of cells during gastruloid formation. This will provide an unprecedented vision of the early organisation of cells in mammalian embryos. Specifically we expect to gain insights into the role that different signalling pathways play in the establishment of the coordimate system of the embryo.
One important development that is already being implemented is the engineering of 'chromobodies' for Nodal, Wnt and FGF signalling. Chromobodies are Nanobodies attached to fluorescent tags that when expressed in cells allow the tracking of signalling events in real time.
A most important final goal is the understanding of how cell densities trigger the programs of gene activity that organize the mammalian embryo,
Also, it would be important to extrapolate these studies to human gastruloids and I hope that my request to do this will be approved
Will also set up a local website associated and dedicated to the project which has been delayed because of pandemic and move.
One important development that is already being implemented is the engineering of 'chromobodies' for Nodal, Wnt and FGF signalling. Chromobodies are Nanobodies attached to fluorescent tags that when expressed in cells allow the tracking of signalling events in real time.
A most important final goal is the understanding of how cell densities trigger the programs of gene activity that organize the mammalian embryo,
Also, it would be important to extrapolate these studies to human gastruloids and I hope that my request to do this will be approved
Will also set up a local website associated and dedicated to the project which has been delayed because of pandemic and move.