Intestinal organoids for assessing nutrient transport, sensing and incretin secretion

Abstract

Intestinal nutrient transport and sensing are of emerging interest in research on obesity and diabetes and as drug targets. Appropriate in vitro models are lacking that allow both, studies on transport processes as well as sensing and subsequent incretin hormone secretion including intracellular signaling. We here demonstrate that murine small-intestinal organoids are the first in vitro model system enabling concurrent investigations of nutrient and drug transport, sensing and incretin hormone secretion as well as fluorescent live-cell imaging of intracellular signaling processes. By generating organoid cultures from wild type mice and animals lacking different nutrient transporters, we show that organoids preserve the main phenotypic features and functional characteristics of the intestine. This turns them into the best in vitro model currently available and opens new avenues for basic as well as medical research.

Enteroids for Nutritional Studies

“…Monolayers of enteroids successfully addressed this issue and were used to investigate transepithelial ion transport and the effect of mutations on the function of CFTR, the major intestinal anion channel that is mutated in cystic fibrosis patients . The sodium‐dependent glucose transporter SGLT1/SLC5A1, proton‐coupled peptide transporters PEPT1/SLC15A1, and bile acid receptor TGR5 were found at the brush border locus of the enteroids, and glucose transporter GLUT2 was found on the basolateral side of the enteroids, which were in line with the in vivo scenario, indicating that enteroids are appropriate models to study nutrient transport . The intestine regulates dietary fat absorption to maintain lipid homeostasis .…”

“…Fluorescent tracers have been used to evaluate epithelial layer permeability in enteroids. For instance, enteroids incubated with sodium‐fluorescein and FITC‐Dextran 4 (FD4) indicated a high permeability for compounds such as glucose, peptides, and fatty acids up to 4 kDa, but not for FITC‐Dextran with a size of 40 kDa . It is broadly accepted that enterocytes play a major role in intestinal barrier function, while nonenterocytes play a vital role in regulation of the intestinal barrier .…”

“…Hence, primary intestinal cells and ex vivo xenograft models have been considered for nutritional studies. Nevertheless, primary cells and ex vivo xenografts often have quite a short lifespan, leading to practical difficulties in nutritional research. Animal models are considered to be the gold standard for in vivo studies, however, they do not reflect the genetic and clinical features of the human tissues .…”

Application of porcine gastrointestinal organoid units as a potential in vitro tool for drug discovery and development

“…Complex 3D organoids are more physiologically and pharmacologically relevant in the development of new chemical entities than simpler 2D models. Mounting studies (Bijsmans et al, 2017;Grabinger et al, 2014;Mizutani et al, 2012;Zietek, Rath, Haller, & Daniel, 2015) have utilized organoids generated from mice and rats to assess the pharmacological and toxicological effects of compounds/drugs.…”

In vitro and in vivo imaging and tracking of intestinal organoids from human induced pluripotent stem cells

“…The small intestine (SI) is a multistructural and multifunctional organ that participates in the uptake of nutrients, provides a barrier function, modulates the intestinal microbiome, and provides host protection against harmful pathogens and toxic substances through a defense mechanism (1). The SI is lined with a complex epithelium that harbors region-specific architecture and multiple cell types comprising absorptive enterocytes and 3 types of secretory cells (Paneth, enteroendocrine, and goblet cells) (2). In addition, to perform its appropriate functions, other specialized cells are integrated into the intestine, such as vascular, neuronal, lymphatic immune, and smooth muscle cells and fibroblasts (3,4).…”