Human Organoid Model To Generate Mucosal Immune Cell Populations

Innate lymphoid cells (ILC) are a type of white blood cell that mainly reside inside organs such as the lungs and the gut. There is a lot of interest in these cells as they have been shown to play important roles in maintaining health and in fighting infections and cancer. Additionally, under certain conditions they have also been shown to drive disease progression. Despite their many roles in the body, ILC exist in small numbers in distant and hard to access tissues, so it is difficult to obtain enough cells to study them. This means that most researchers turn to the use of animals, such as mice, for their studies as ILC are much easier to obtain this way. This project aims to establish a technology by which to generate human ILC in sufficient numbers for experimental studies and can therefore be used to replace the need for mouse models.

Recently, we discovered that organoids, these are mini-organs grown in the lab in a dish, are able to support the generation of large numbers of human ILC. We can easily obtain cells that have the capacity to become ILC (ILC precursors) from blood. Then, we add these precursor cells to the mini-organs where they are able to grow and fully development into ILC. Moreover, the type of mini-organ used is important for the development of these cells. The ILC grown in mini-guts are similar to ILC taken straight from the human the gut whilst ILC that grow in mini-lungs are similar to those taken from the lung. With this project we aim to further develop and validate this technology by analysing in detail the characteristics of the ILC that grow in our mini-organs. This will provide reassurance to the scientific community that these cells are able to accurately resemble the ILC found in the human body and so other scientists can confidently use this technology to grow cells for their studies.

By doing this we aim for this technology to be widely adopted by the scientific community leading to ILC generated in our mini-organs to replace the use of mouse ILC in certain studies. As this technology advances, so will the number of studies in which this model will be able to be used instead of mice. Moreover, our technology has the additional benefit that as the cells being used are taken from humans they are able to more accurately model the roles of ILC in human health and disease

Innate lymphoid cells (ILC) are tissue associated cells able to mount rapid immune responses associated with potent cytokine production. Interest in these cells is growing due to new understanding of their roles in modulation of adaptive immune responses, epithelial regeneration, anti-tumour responses, neural communication, and interactions with the microbiota. However, the difficulty in obtaining sufficient ILC numbers from human samples means the majority of research is reliant on mice. We aim to establish a technology providing a reliable source of human ILC leading to the replacement of their use in studies which are currently dependant on mouse models.
Here we aim to validate our system that uses organoids to generate large numbers of human ILC with tissue-specific phenotypes. ILC precursors, easily obtained from human blood, will be co-cultured with human induced pluripotent stem cell (hIPSC) derived mucosal organoids. We have previously shown in small intestine and lung organoid cultures that this system leads to the development of the various ILC subsets with characteristics similar to their in vivo counterparts. We now aim to further characterize these ILC and expand this technology to colon organoids. ILC will be harvested from the co-cultures and their transcriptomic (scRNA-seq) and functional phenotype (cytotoxicity, antigen presentation, cytokine production) will be characterized in detail. These data and detailed protocols will be publicly available and widely disseminated to aid the adoption of this technology by future users.

This study is crucial to gain the confidence of the scientific community on the potential of this technology, reassuring the biological significance of organoid-generated ILC and promoting its wide adoption for discovery and translational science. Accordingly, this technology aims to replace mouse ILC studies for human ones, which has the additional of advantage of increasing their relevance for the study of human biology.