Incorporation of the PSGL-1/SLeX rolling machinery promotes rapid homing of MSCs to inflamed ear pinna. (A) Representative images of native MSCs (blue, DiD) and PSGL-1/SLeX MSCs (green, DiI) in healthy and inflamed mice ears (red, blood, rhodamine-dextran). (B) Quantitative analysis of MSC homing to the inflamed ear. Transfected MSCs exhibit statistically significant enhanced homing to the LPS-induced inflamed ear vs native MSCs at 2 hours postinjection (*P < .05, 1-way ANOVA using Tukey’s HSD; error bars represent ± SEM) (n = 4 and n = 7 for 2 hours and 24 hours, respectively). (C) A direct comparison between PSGL/SLeX MSCs and PSGL-1/SLeX/IL-10 MSCs reveals similar homing to inflamed ear pinna (ns = no statistical difference observed between the 2 groups at each time point; 1-way ANOVA using Tukey’s HSD; error bars represent ± SD, n = 4). Rapid clearance of MSC is observed, with peak number of cells observed at 24 to 48 hours and a significant decrease observed at 72 hours after cell administration (stack dimensions are 474 × 488 microns; *P < .05, 1-way ANOVA using Tukey’s HSD).