Increased yield of gelatin coated therapeutic cells through cholesterol insertion

Abstract

Gelatin coatings are effective in increasing the retention of MSCs injected into the heart and minimizing the damage from acute myocardial infarction (AMI), but early studies suffered from low fractions of the MSCs coated with gelatin. Biotinylation of the MSC surface is a critical first step in the gelatin coating process, and in this study, we evaluated the use of biotinylated cholesterol “lipid insertion” anchors as a substitute for the covalent NHS‐biotin anchors to the cell surface. Streptavidin‐eosin molecules, where eosin is our photoinitiator, can then be bound to the cell surface through biotin‐streptavidin affinity. The use of cholesterol anchors increased streptavidin density on the surface of MSCs further driving polymerization and allowing for an increased fraction of MSCs coated with gelatin (83%) when compared to NHS‐biotin (52%). Additionally, the cholesterol anchors increased the uniformity of the coating on the MSC surface and supported greater numbers of coated MSCs even when the streptavidin density was slightly lower than that of an NHS‐biotin anchoring strategy. Critically, this improvement in gelatin coating efficiency did not impact cytokine secretion and other critical MSC functions. Proper selection of the cholesterol anchor and the biotinylation conditions supports cellular function and densities of streptavidin on the MSC surface of up to ~105 streptavidin molecules/μm2. In all, these cholesterol anchors offer an effective path towards the formation of conformal coatings on the majority of MSCs to improve the retention of MSCs in the heart following AMI.

Polymer Cell Surface Coating Enhances Mesenchymal Stem Cell Retention and Cardiac Protection

“…13 Our previous results also demonstrated that gelMA-coated cells have a similar morphology and cell structure to unmodified cells. 13 In addition, we have shown in vitro that gelMA coating did not influence the metabolic activity of coated cells, their immunogenicity or survival. 12 In vivo transplantation of coated cells have also been shown to be safe without a heightened immune response.…”

“…11 Our groups have recently developed a cell surface coating strategy that polymerizes biodegradable gelMA coating on bone marrow cells. 12,13 The presence of cell coating can be detected by flow cytometry or epifluorescence microscopically as demonstrated in our recent publication. 13 Our previous results also demonstrated that gelMA-coated cells have a similar morphology and cell structure to unmodified cells.…”

“…12,13 The presence of cell coating can be detected by flow cytometry or epifluorescence microscopically as demonstrated in our recent publication. 13 Our previous results also demonstrated that gelMA-coated cells have a similar morphology and cell structure to unmodified cells. 13 In addition, we have shown in vitro that gelMA coating did not influence the metabolic activity of coated cells, their immunogenicity or survival.…”

An immunometabolic patch facilitates mesenchymal stromal/stem cell therapy for myocardial infarction through a macrophage‐dependent mechanism

“…These strategies include modifying the properties of MSCs, such as increasing the expression of adhesion factors or inflammatory cytokine receptors, 33 , 34 preconditioning MSCs with toxic elements, exposure to a hypoxia‐ or nutrient‐free environment, 35 , 36 and magnetic targeting techniques. 37 Meanwhile, emerging studies have focused on the encapsulation of MSCs within biomaterials, including injectable hydrogels, 38 , 39 scaffolds, 40 gelatin coatings, 41 and microneedles. 42 Nevertheless, current strategies are limited by the inefficient interactions between implanted cells and excessively inflammatory tissue.…”