How to build a mini-stomach: using multi-regional organoids to engineer gastric epithelium

Background
Gastrointestinal (GI) organ failure, from congenital or postnatally acquired pathologies, is a major cause of death across countries of all income levels. At present, definitive treatment for GI organ failure is by transplantation, with the best outcomes seen in solid organ transplantation in adults. However, complications of immunosuppression, a shortage of organs, and donor-recipient size mismatch, particularly in children, render this treatment strategy suboptimal. Despite significant advances in supportive care programs, if adaptation is inadequate, premature mortality follows. Therefore, there is an unmet need for an alternative approach to long-term organ replacement therapy, especially for paediatric luminal organ failure1.
Signals responsible for the regionalisation and diversity of cell types of the human stomach are not fully understood. To generate truly personalised cell and gene therapies for gastric conditions, these fundamental unknowns must be addressed. We have developed a system using foetal and paediatric gastric organoids2–4 that demonstrates the ability of organoids to retain their regional identity in culture and self-assemble into ‘mini-stomachs’ containing all three gastric regions (fundus, body, antrum).

Aims/Objectives
– To examine the different behaviour of organoids derived from fundus, body, and antrum of the stomach in response to an array of molecular signals
– To investigate the differing contributions of putative gastric stem cells to organoid formation from each region
– To study intercellular and intracellular signals responsible for self-assembly behaviour observed in fundus, body, and antrum organoids
– To develop a technique to study large scale self-organisation properties of gastric organoids
– To optimise the human gastric organoid model to study host-pathogen interaction
– To generate a multi-region model of the human stomach in vitro

Methods
During this 3-years project, the PhD student will learn several types of 3D cell culture techniques, the use of bioreactors, analysis techniques including tissue fixation & sectioning, immunostaining, confocal and multi-photon microscopy, ELISA, RNA extraction, qPCR, RNA bulk and single cell sequencing, cytometry by time-of-flight (with a collaborator).

References
1. Jones, B. C., Shibuya, S., Durkin, N. & De Coppi, P. Regenerative medicine for childhood gastrointestinal diseases. Best Pract. Res. Clin. Gastroenterol. 56–57, 101769 (2022).
2. Giobbe, G. G. et al. SARS-CoV-2 infection and replication in human gastric organoids. Nat. Commun. 12, 1–14 (2021).
3. Jones, B. C., Calà, G., De Coppi, P. & Giobbe, G. G. Paediatric gastric organoids as a tool for disease modelling and clinical translation. Pediatr. Surg. Int. 1, 3 (2021).
4. Giobbe, G. G. et al. Extracellular matrix hydrogel derived from decellularized tissues enables endodermal organoid culture. Nat. Commun. (2019) doi:10.1038/s41467-019-13605-4.