Fig. 3

Gene expression changes in MSCs following inflammatory priming and/or inflammatory macrophage exposure. MSCs exposed to polyinosinic:polycytidylic acid (poly I:C) or interferon gamma (IFN-γ), and then to inflammatory macrophages. Resultant changes in expression of (a) immunogenicity, (b) inflammation, and (c) immunomodulatory genes measured and compared to untreated, control MSCs using the 2^–ΔΔCT method. Priming with IFN-γ and or inflammatory macrophage exposure induced significant increases in (a) MHC-I, MHC-II, (c) IL-6, CCL2, and CXCL10 expression. Priming with poly I:C alone produced few significant changes in gene expression with the exception of (b) IDO, and sequential exposure to poly I:C then inflammatory macrophages induced significant upregulation of IDO compared to inflammatory macrophage exposure alone. Box and whisker plots represent n = 8 individual horses. Groups not sharing same uppercase letter are significantly different, p < 0.05; repeated-measures ANOVA, with horse as a random effect, followed by a Tukey HSD test for multiple comparisons. MSC mesenchymal stem cell, MHC major histocompatibility complex, poly I:C polyinosinic:polycytidylic acid, IFN-γ interferon gamma, IDO indoleamine 2,3-dioxygenase, NOS2 inducible nitric oxide synthase, PTGS2 prostaglandin-endoperoxide synthase 2, IL interleukin, CCL2 C-C motif chemokine 2, CXCL10 C-X-C motif chemokine 10