Generating an in vitro gut model with physiologically relevant biophysical mucus properties

Abstract

IntroductionGastrointestinal (GI) in vitro models have received lasting attention as an effective tool to model drug and nutrient absorption, study GI diseases, and design new drug delivery vehicles. A complete model of the GI epithelium should at a minimum include the two key functional components of the GI tract: mucus and the underlying epithelium. Mucus plays a key role in protecting and lubricating the GI tract, poses a barrier to orally administered therapies and pathogens, and serves as the microenvironment for the GI microbiome. These functions are reliant on the biophysical material properties of the mucus produced, including viscosity and pore size. MethodsIn this study, we generated in vitro models containing Caco-2 enterocyte-like cells and HT29-MTX goblet-like cells and determined the effects of coculture and mucus layer on epithelial permeability and biophysical properties of mucus using multiple particle tracking (MPT). ResultsWe found that mucus height increased as the amount of HT29-MTX goblet-like cells increased. Additionally, we found that increasing the amount of HT29-MTX goblet-like cells within culture corresponded to an increase in mucus pore size and mucus microviscosity, measured using MPT. When compared to ex vivo mucus samples from mice and pigs, we found that a 90:10 ratio of Caco-2:HT29-MTX coculture displayed similar mucus pore size to porcine jejunum and that the mucus produced from 90:10 and 80:20 ratios of cells shared mechanical properties to porcine jejunum and ileum mucus. ConclusionsGI coculture models are valuable tools in simulating the mucus barrier and can be utilized for a variety of applications including the study of GI diseases, food absorption, or therapeutic development. BiographyDr. Maisel joined the University of Maryland in January 2019 having done interdisciplinary training in nanotechnology, mucosal immunology, lymphatic immunology, and immunoengineering. She completed her PhD in Biomedical Engineering at the Johns Hopkins University in 2014 after which she was an NIH postdoctoral fellow at the University of Chicago in Molecular Engineering and Immunology. The Maisel Lab uses in vitro modeling, nanotechnology, and immunoengineering approaches to study and develop treatments for diseases at mucosal surfaces. They are interested in designing nanoparticles to take advantage of and study the interface between biological barriers, particularly the lymphatics, interstitial tissue, and mucosal surfaces, and nanoparticles. Dr. Maisel has won a number of awards, including NSF GRFP and NIH F32 fellowships as a trainee, the American Lung Association Dalsemer Award, LAM Foundation Career Development Award, an NSF CAREER Award, and an NIH NIGMS Maximizing Investigator Research Award. Her work has led to numerous high-impact publications, particularly in the field of drug delivery and mucosal immunoengineering, and several patents.