Fig. 1: Genetic engineering of S. boulardii to express mSA handle on the cell surface for attachment of ECM-specific targeting ligands.

A Schematic of engineering steps to enable the binding of S.b. to extracellular matrix proteins. B Schematic of key components of plasmid used to engineer stable expression of monomeric streptavidin (mSA) on the yeast surface. C Representative fluorescent images of S.b. mSA (left) and S.b. (right) attached to a biotin-coated well plate incubated at varying initial cell concentrations (starting OD₆₀₀ = 0.5, 0.25, or 0.125). Scale bars are 100 μm. D Quantification of attached S.b. on the biotin-coated well plate. Images were quantified using ImageJ, n = 3 wells per condition. Data are shown as mean ± SD. Significance was determined using unpaired, two-tailed Student’s t-tests, n = 3 per condition. E Mean fluorescence intensity (MFI) values resulting from labeling S.b. mSA with titrating concentrations of biotinylated antibodies against fibronectin (FN, blue), fibrinogen (FB, purple), or collagen IV (CIV, red) or non-biotinylated antibodies (grey) as measured by flow cytometry (n = 3, points represent mean). F Collection of fold change values in colonic expression of fibronectin (Fn1), fibrinogen (Fgb), or collagen IV (Col4a1) in human subjects with active ulcerative colitis (n = 181) as compared to healthy subjects (n = 82) from 7 whole-genome transcriptional analysis datasets. For violin plots, the mean is represented by the solid line and interquartile ranges represented by dotted lines. Significance assessed by unpaired, two-tailed Student’s t-tests. α = 0.05, *p < 0.05, **p < 0.01, ****p < 0.0001.