Intestinal organoids as a replacement strategy to unravel early host intestinal epithelia interactions with whipworms

Lead Research Organisation: The Wellcome Trust Sanger Institute
Department Name: Pathogen Variation

Abstract

Trichuriasis is a major Neglected Tropical Disease affecting mainly children from low and middle income countries. This disease is characterized by abdominal pain, diarrhea and anemia and it is linked with physical and intellectual growth retardation. Trichuriasis is caused by infection with whipworms, which occurs upon ingestion of eggs of these parasites present on food or water. In the gut, the eggs hatch, liberating larvae that then burrow through the gut lining (epithelium). The initial stages of the epithelium infection by the larvae are thought to be crucial in determining if the parasite is expelled or if it remains in the gut causing a chronic disease. However, up to now, the details of these initial interactions between the whipworm and the gut epithelium are not understood, hampering the development of therapies to eradicate and vaccines to prevent whipworm infections.

Presently, studies on interactions between gut epithelium and whipworms are done by infecting mice with mouse whipworms and require large numbers of animals. The high dependency on the use of mice to do research in trichuriasis affects the size of the community of scientists that investigate this disease and also may compromise our understanding of human infections. My goal in this project will be to develop a new model to study whipworm-gut epithelium interactions using miniature (mini) guts. Mini-guts (also called organoids) are 3D cell clusters generated from gut tissue that have similar characteristics and function to the gut. Mini-guts can be kept alive in the lab for long time, and they can also survive freezing and thawing, allowing to do many experiments using the same material. Recently, I have established a method to inject the mini-guts with whipworm larvae that I propose as a model to replace mouse-whipworm infections. Besides the replacement of mouse use in trichuriasis research, this technique has additional advantages: first, it will allow me to more precisely look at how whipworms interact with the gut cells since I will be able to watch the infection live; and second, in the future, using human mini-guts and human whipworms we will understand much better the human disease. Ultimately, I want to identify the very first steps that occur during the initial contact and infection of whipworm larvae in the gut. To do so, using mini-guts I propose to do assays including microscopy and sequencing and test the changes that happen during infection on the whipworm and the gut epithelium.

This project will benefit both scientists and the society in general as it will: 1) provide a new model to study Trichuriasis replacing mice infections, 2) will increase our knowledge on whipworm-gut interactions and 3) in the future, it will help to develop vaccines and discover drugs to fight whipworm infections in low and middle income countries thus improving the quality of life of their children.

Technical Summary

Aim: Early host intestinal epithelial cells (IECs)-whipworm (Trichuris sp) interactions and their implications in the immune response that determine the expulsion or establishment of the parasites in their host are not understood. This research project aims to investigate and understand these interactions in detail, and in so doing, demonstrate a viable alternative to the infection of mice with T. muris. To achieve this, I will exploit intestinal organoids as a replacement model of the murine infections that are currently used.

Objectives and Methodology: Specifically, I will: First, refine and validate the organoid-whipworm larvae infection model, by optimisation of the protocols to generate of mouse caecal organoid lines and to infect them by microinjection of T. muris larvae; second, identify the IEC-type targeted by the parasite by visualising active infection using diverse microscopic techniques; third, conduct transcriptomic, proteomic, flow cytometry and cytokine analysis to discover host IECs-whipworm interactions and evaluate IECs responses to whipworm larvae infection; fourthly, characterize the role and the mechanisms of action in the early host-parasite interaction of several novel IECs genes using mutant organoids; and finally, pilot the use of human organoids as a T.trichiura infection model. The organoid model will be validated by comparison with data already obtained from murine infections.

Scientific opportunities: This project will result in the implementation of a novel model to study Trichuris infections, will generate fundamental data on host-whipworms interactions and also support future efforts to control these parasites by the identification of potential new therapeutic targets.

Publications

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