Antigoni's first project in the lab (when she started as an Erasmus student in our lab a few years back) is now out as a preprint on Biorxiv: https://www.biorxiv.org/content/10.1101/2021.09.24.461516v1.full. In this we dissect the links between the function of the key transcription factor (responsible for posterior embryonic body development), human neuromesodermal progenitor (NMP) induction and posterior neural crest (NC) specification using hPSC differentiation as a model. We found that:
(i) disruption of NMP induction/mesoderm competence via knockdown of TBXT abolishes the acquisition of a posterior axial identity by NC cells but not CNS spinal cord pre-neural progenitors
(ii) TBXT mediates early posteriorisation in NMPs/prospective NC cells in conjunction with WNT signalling by directly orchestrating an open chromatin landscape in HOX clusters
(iii) control of trunk HOX gene expression/posteriorisation in NMP-derived CNS spinal cord pre-neural progenitors appears to be TBXT/WNT-independent and programmed after NMP differentiation primarily under the action of FGF signalling.
This work indicates the existence of two distinct phases of posterior axial identity control: (i) an early NMP-based that involves the TBXT/WNT-driven establishment/fixing of a HOX-positive, posterior character in uncommitted progenitors followed by its “transmission” to their downstream trunk NC derivatives and, (ii) a later one, which is based on the FGF-driven sculpting of a posterior axial identity in cells transiting toward a spinal cord neural fate, post-NMP differentiation:
Matt's PhD paper is now out in Development: https://dev.biologists.org/content/early/2021/02/26/dev.194415. In this we describe a method for producing in the petri dish motor neurons that correspond to the lower part (thoracic) of the spinal cord using human pluripotent stem cells. These cells offer a promising tool for modelling neurodegenerative conditions affecting the spinal cord and also a potential cell therapy source for treating spinal cord injuries. Our review on the biology of the progenitors of these motor neurons (as well as other cell types that make up the body trunk) has also just been published in Development: https://dev.biologists.org/content/148/4/dev180612.
Tom's latest paper (=November's bioRxiv preprint) focusing on the in vitro generation of vagal neural crest and enteric nervous system progenitors is now published in Stem Cell Reports: https://www.cell.com/stem-cell-reports/fulltext/S2213-6711(20)30301-5. The work is a result of a great collaboration with Conor McCann, Nihil Thapar and Alan Burns from the UCL Great Ormond Street Institute of Child Health and forms the basis of our joint efforts to develop a stem cell-based therapy to treat Hirschsprung disease (see below). For more details see also here.
Our lab is featuring in the first of the new series of ResearchFocus interviews by our funders Children's Cancer and Leukaemia Group (CCLG): https://www.cclg.org.uk/news/research-focus-dr-anestis-tsakiridis
We are grateful to the MRC and its Populations and Systems Medicine Board, for funding our grant application 'Developing a human pluripotent stem cell-based strategy for treating Hirschsprung's disease'. The project is a collaboration with colleagues from the UCL Great Ormond Street Institute of Child Health and aims to develop a stem cell therapy for the treatment of Hirschsprung disease, a life-threatening enteric neuropathy that affects approximately 1 in 5000 live births, making it one of the most common congenital diseases affecting the gut.
Neuroblastoma UK's new blog feature on how we use hPSC-derived trunk neural crest cells to model Neuroblastoma in the petri dish: https://www.neuroblastoma.org.uk/news/2020/1/16/dr-anestis-tsakiridis
Tom's new paper (in collaboration with Peter Andrews here in Sheffield and also Conor McCann, Nikhil Thapar and Alan Burns from the UCL Great Ormond Street Institute of Child Health) on the role of retinoic acid in generating vagal neural crest cells from hES cells is now out on bioRxiv: https://www.biorxiv.org/content/10.1101/819748v1
We also describe the accelerated in vitro generation of functional human enteric neural progenitors and enteric neurons/glia. We next hope to exploit these findings for the development of a cell-based therapy to treat aganglionic gut disorders such as Hirschsprung's disease.
Our group together with the Peter Andrews lab (Centre for Stem Cell Biology, Biomedical Science Department) are now part of a network of 7 partner universities that has been awarded an EU grant of almost €7 million. The project (CONNECT: “Connecting neural networks: Nervous-system-on-Chip Technology”), which was launched last week with a kick-off meeting in Eindhoven, Netherlands, brings together a wide range of research disciplines aiming to develop a new type of organs-on-a-chip (OoC) for modelling Parkinson’s disease.
OoC is a case with tubes, called microfluidic channels, which allows experiments to be done on living cells. Well-known examples of OoCs are liver-on-a-chip and heart-on-a-chip. In vitro experiments involving OoCs offer the advantage that they are easy to repeat: unlike animal models such as mice, OoCs are very similar to each other. This makes it much easier to repeat an experiment. The hope is that with a complete understanding of an organ, researchers will be able to produce a perfectly functioning OoC, in which new drugs can be tested on a large scale.
Eindhoven University of Technology (TU/e) is leading this new research consortium aiming at developing a nervous-system-on-a-chip (NoC), which could be used, for example, to test new drugs against Parkinson's disease. It could also help reduce the number of animal experiments, bringing both ethical and practical benefits. The NoC will connect different types of nerve cells to each other, through three compartments, aiming to mimic the “natural” connections that exist between the central and peripheral nervous system, in the human body. This will in turn, allow the study of the transport of specific proteins that travel in the nervous system and are associated with Parkinson's disease. The role of the University of Sheffield groups in this project is to produce the appropriate peripheral nervous system components, such as enteric neurons, using human pluripotent stem cells (hPSCs) as a starting material. Other partners include the University of Luxembourg which will be involved in growing organoids from hPSCs i.e. structures that mimic specific human brain cells whereas optical and electrophysiological analysis of the resulting nerve cells will be done by KU Leuven (Belgium) and the Erasmus MC (Netherlands) respectively. AALTO University (Finland) will help with the choice of materials and electrodes for the construction of the NoC while the Oxford Parkinson Disease Center will provide cells from Parkinson's patients for testing. The TU/e researchers will take care of the design and realisation of the NoC.
The project will open the door to personalized medicine approaches involving the rapid testing of candidate drugs directly on patient cells. This will also accelerate the development of new medicines, something that is currently desperately needed, given that a new drug has an average development time of 10 to 12 years and costs about 1.6 billion Euros.
Our lab's first paper looking at the links between human axial progenitors and posterior neural crest ontogeny has just been published in eLife: https://elifesciences.org/articles/35786
Below is a model summarising our findings on the signals and the progenitors involved in the in vitro generation of neural crest (NC) subtypes of distinct anterior-posterior identity from hPSCs. Examples of unique genes that we found to mark each NC population exclusively are shown in red.
Summary for non-specialists:
Trunk neural crest is a very important cell type which, during embryonic development gives rise to a family of neurons that control the function of crucial organs such as the heart (known as “sympathetic” neurons) as well as hormone-producing cells of the adrenal gland. When “mutated”, these cell groups are also the founders of neuroblastoma, the most common childhood solid tumour. Despite their importance, not much is known about how human trunk neural crest cells arise in utero or how they produce neuroblastoma in some “abnormal” cases. To address these issues, ideally we need to access easily and study large numbers of human trunk neural crest cells, something which is currently impossible. In our rcently published study, we provide a solution to this problem. Specifically, we report the generation of relatively pure populations of trunk neural crest cells in the petri dish from human pluripotent stem cells (hPSCs), unspecialized cells that resemble the early human embryo and can produce any cell type in the body when treated with the appropriate cocktails of chemicals. We found that these petri dish-produced trunk neural crest cells can be then converted efficiently into sympathetic neurons which have the same properties as their in vivo counterparts. Our work opens new avenues in the field of stem cell “bioengineering” providing the opportunity to understand better the biology of human trunk neural crest cells and neuroblastoma without the need to use of animal models or primary human foetal tissue. This work was done in collaboration with the groups of Peter Andrews, Marysia Placzek and Stuart Johnson from the Biomedical Science Department in the University of Sheffield as well as researchers from research centres in three different countries (The Francis Crick Institute, London; MRC Centre for Regenerative Medicine, Edinburgh; High Performance Computing and Networking Institute, Italy; Biotechnology Center/Max Delbrück Center for Molecular Medicine, Germany).