Background: Pro-obesity diets can drive global changes to the intestinal landscape. A high fat diet (HFD) disrupts the existing gut microbiome which has direct effects on the epithelial cells lining the gut mucosa[1]. Although many studies link HFD to intestinal dysfunction, little is known about how diet-induced changes to the mucosal composition can drive the development of obesity and type 2 diabetes. Intestinal organoids have been widely used to study epithelial cell function and mucosal regeneration in response to different dietary conditions[2]. We aim to use intestinal organoids to investigate how the mucosal cell composition changes in response to a high fat environment by assessing the relative densities of different epithelial cell types over 7-day period.
Method: Small intestinal organoids established from C57BL/6J mice were exposed to oleic acid (OA) for 7 days. A multi-colour flow cytometry panel with gut specific cell markers were used to interrogate changes in the proportion of epithelial cell types after day 3 and 7 of OA exposure. Changes in organoid morphology were analysed using a brightfield microscope and ImageJ.
Results: Exposure to OA significantly increased the size and crypt depth of jejunal and duodenal organoids after 24 hours of treatment. FACS analysis of organoid cells after 72 hours indicate that OA increases the proportion of transit amplifying cells and secretory progenitors, while reducing the density of absorptive cells and absorptive progenitors. The proportion of enteroendocrine and tuft also increased 3 days post OA treatment.
Conclusions: Fat exposure increases transit amplifying cell proliferation, which are known to promote organoid growth and crypt elongation. OA exposure appears to steer the differentiation trajectory of epithelial cells towards a secretory cell fate. Whether this augments the long-term density of hormone-producing enteroendocrine cells, which are important regulators of metabolism and gut motility, is yet to be investigated further.