Quantifying and Engineering Mucus Adhesion of Probiotics

Abstract

Mucus in the gastrointestinal (GI) tract is the primary point-of-interaction between humans and their gut microbiota. This not only intimates that mucus ensures protection against endogenous and exogenous opportunists but provision for the human microbiota to reside and flourish. With the emergence of living therapeutics, engineered microbes can deliver and produce increasingly complex medicine, and controlling the mucoadhesive properties of different microbial chassis can dictate dose-response in a patient. Here we present a redesigned, in vitro, plate-based assay to measure the mucus adhesion of various probiotics. Cell-mucus interactions were isolated by immobilizing mucus to the plate surface. Binding parameters were derived for each probiotic strain by measuring cell adhesion over a wide range of cell concentrations, providing dosedependent adhesion metrics. Surface proteins and cell components known to influence mucoadhesion were then heterologously expressed or altered in Lactococcus lactis MG1363 and E. coli Nissle 1917 to control mucus-binding capacity, avidity, and cooperativity.

Modulating the Bioactivity of Mucin Hydrogels with Crosslinking Architecture

“…The importance of ligand presentation was also suggested for mucin coatings, which interacted differently with bacteria depending on the site by which the molecule was attached to the surface. [28,29] Thus, we hypothesize that the architecture of the hydrogel could affect its bioactivity by affecting ligand density, adding or removing steric hindrances to interactions, or allowing the co-presentations of new ligands. The architecture of a hydrogel can be tuned by the details of the chemical crosslinking of the components.…”

A quantitative model for metabolic intervention using gut microbes

“…Unfortunately, the physiology of the gut does not lend to metabolic intervention easily, and each age group had plasma phe ubiquitously increase to unsafe levels (Figure 4). As a countering tactical measure, drug formulations for living therapeutics include microencapsulation to survive the stomach (39), surface modification to improve mucoadhesion and increase residence time or cell population (16), bacterial chassis selection to target regional success (40, 41), and enzyme choice and expression to increase specific activity per cell (40, 41). Effectively, the agenda in each case is to increase the level of therapeutic intervention at earlier stages of digestion.…”

Evaluation of the Function of Probiotics, Emphasizing the Role of their Binding to the Intestinal Epithelium in the Stability and their Effects on the Immune System

“…Lactobacillus and Bifidobacterium are the most important gram-positive lactic acid bacteria that have common surface molecules such as surface layer proteins, Mub, and lipoteichoic acid, which have a crucial role in interacting with mucosal constituents [ 141 , 142 ]. Intestinal surface bacterial adhesion can be initially induced by nonspecific contacts such as hydrophobic interactions, accompanied by the second phase of adhesion by specific cell wall constituents [ 143 ]. Surface adhesive proteins, including MucBP and Mub [ 144 ], are mucus-binding proteins.…”