Organ-restricted adult stem cell derived 3D replicas of organs grown in tissue culture, termed organoids, have led to remarkable advances in stem cell and developmental biology, cancer and regenerative medicine. Organoids are now poised to advance our understanding of infectious disease because they accurately recapitulate the essential function and architecture of intact tissues. Our aim is to establish organoids to models natural infection by pathogens of public health importance.
Using protocols established by the Clevers laboratory in the Netherlands, we have successfully established organoids from mouse small intestine, colon and liver; and human colon and liver. Briefly, the stem cells compartments of these tissues are resuspended in an extracellular matrix (Matrigel), and seeded into tissue culture plates. Once the Matrigel has set, it is covered with medium containing growth factors necessary for stem cell maintenance and tissue organization. The stem cells self-organise into organoids giving rise to all the cells type normally derived from the stem cell. Using immunofluorescence and confocal microscopy, quantitative RT-PCR and immunohistochemistry, we have characterised gut and liver organoids and demonstrated that they faithfully recapitulate adult tissue. We have demonstrated that material can be microinjected into the lumen of organoids, and that we can establish organoids from diseased tissues such as human cancer. Furthermore, the organoids are readily genetically manipulated to study gene function.
Tissue-restricted stem cell derived organoids recapitulate the characteristics of the intact adult tissue and are readily infected with viruses that only infect specific adult human cell types. We will now expand our tissue repertoire to include lung organoids as infection of the respiratory tract, gut and liver accounts for the majority of human infectious diseases, globally.