Human organoids with an autologous tissue-resident immune compartment.
Intestinal immuno-organoid (IIO) model for drug induced inflammation
Introduction
Organoids model important aspects of human physiology and play an important role in drug discovery. However, to date, they have been lacking a tissue-specific immune compartment.
The intestinal mucosal immune system is the largest pool of immune cells in the human body. It ensures homeostasis by constant policing of the interface between the intestinal barrier and luminal contents. Disruption of intestinal immune function can lead to various pathologies, including persistent infections and autoimmune and even malignant disease.
In this paper, the authors incorporated tissue-resident memory T (TRM) cells, with epithelial organoids generated from the same human tissue sample. These intestinal immuno-organoids (IIOs), containing an autologous immune compartment, were then characterised and used to recapitulate and investigate drug-induced intestinal inflammation.
Main Points
- The author’s found that in the absence of external stimulation, a subpopulation of TRM cells infiltrated the organoids and integrated within the epithelial barrier, resembling the behaviour of intestinal intraepithelial lymphocytes (IELs). In contrast, when matched peripheral blood mononuclear cells were combined with organoids, no apparent interaction with the epithelial cells could be detected.
- To understand how TRM cells and IELs integrate with intestinal epithelial cells in vitro, they benchmarked cell states in the IOOs through comparison with reference atlases using single cell transcriptomes.
- The author’s found that TRM cells cultured alone or within IIOs, unlike their matched blood-derived counterparts, were transcriptomically defined by: (1) the absence of receptors necessary for lymph node homing (SELL, CCR7), (2) intrinsically high expression of intestinal homing and integration factors (ITGA1, CCR9, JAML) and (3) a complete absence of cytotoxic granules (GZMB, GZMK, GNLY).
- To assess whether IEL-containing IIOs could predict targeting of the healthy epithelium, IIOs were treated with an EpCAM-targeting, T cell-bispecific (TCB) molecule at clinically relevant concentrations. Expression of caspase 3/7 was detected as early as 8 h following treatment, demonstrating a dose-dependent toxicity of TCB. Furthermore, supernatants from the TRM cell IIO cultures showed elevated levels of key cytokines TNF, IFNγ, Granzyme B (Gzmb), IL-2 and GM-CSF, indicative of an inflammatory response.
- Interestingly, using the TNF-blocking antibody adalimumab in the IIOs following TCB treatment, significantly reduced the expression of key activation and differentiation markers ICAM-1, 4-1BB, CD25 and Gzmb in TRM cells. Furthermore, expression of CCL2, a chemokine expressed by the epithelium in response to inflammation, as well as epithelial cell apoptosis itself, were significantly reduced.
Conclusion
This intestinal immune-organoid model described in this paper, provides an example of self-organization between human immune cells and epithelial organoids to form an organoid system with a tissue-resident immune compartment which is directly integrated within the IIO epithelial barrier.
The authors show that the model can recapitulate aspects of clinical outcomes, such as drug-induced intestinal inflammation providing the opportunity for in-depth analysis of underlying immunological events in the context of tumorigenesis, and infectious and autoimmune diseases.
EPISTEM SERVICES
Epistem provides 3D organoid models from several species that mimic the intestine, offering valuable insights into biology, disease, and compound effects. These structures allow for multiple assessments, including viability, branching, TEER and gene expression. Furthermore, there is a routine deployment of multi-modal assessment studies including scRNA-seq of a wide variety of tissues and cells utilising a range of expertise to delineate cellular compartmentalisation and function. To aid in the assessment we have a live imaging system and a 15 colour Novocyte flow cytometer, which gives the opportunity to evaluate treatment effects and elucidate the function of specific immune cell types ex vivo.
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