Endoscopic Bowel Injections of Mesenchymal Stromal Cells Alleviate Experimental Colitis

s(αSMA and fibronectin) in fibroblasts stimulated for 48 hours with IL-13 (100 ng/ml), IL-4 (100 ng/ml), or TGFβ (10 ng/ml, a well-known inducer of fibrosis).To explore a role for JAK-STAT6 signaling in IL-13-induced periostin expression, BEF-T fibroblasts were transfected with STAT6 siRNA, treated with a STAT6 inhibitor (AS1415799, 600nM), or treated with a JAK inhibitor (Ruxolitinib, 100nM), and periostin protein expression was determined by Western blot or ELISA at 48 hours.To assess fibroblast functional activity, BEF-T cells (unaltered or transfected with STAT6 siRNA), were seeded in collagen matrices and stimulated with IL-13 or IL-4 for 48 hours; collagen contraction was determined by measuring the change in surface area of collagen gels over 4 hours.Results: In BEF-T and FEE4-T, IL-13 and IL-4 increased expression of periostin (but not αSMA and fibronectin), whereas TGFβ increased expression of αSMA and fibronectin (but not periostin).The increase in periostin induced by IL-13 was blocked by STAT6 siRNA (determined by Western blot), AS1415799, and Ruxolitinib (Fig. 1a).This effect of JAK-STAT6 inhibitors was confirmed in primary fibroblasts HEF at 24 hours (Fig. 1b).IL-13 induced collagen matrix contraction (Fig. 2a), but this contraction was not blocked by STAT6 siRNA (Fig. 2b).Similar findings were observed for stimulation with IL-4.Conclusions: Th2 cytokines induce periostin expression and collagen matrix contraction in esophageal fibroblasts.The Th2 cytokineinduced periostin expression is regulated by JAK-STAT6 signaling, but the collagen matrix contraction is independent of periostin expression and STAT6 signaling.These studies have identified two different mechanisms whereby Th2 cytokines might contribute to esophageal remodeling in EoE, one of which is blocked by JAK-STAT6 inhibitors.Our findings suggest a potential role for JAK-STAT6 inhibitors to prevent esophageal fibrosis in EoE by blocking fibroblast expression of periostin.JAK-STAT6 inhibitors block IL-13-induced periostin protein secretion by BEF-T at 48 hours (Fig. 1a) and by primary fibroblasts HEF (Fig. 1b) at 24 hours as determined by ELISA.(Fig. 2a) IL-13 induce greater collagen matrix contraction in BEF-T compared to baseline contraction in control media.(Fig. 2b) BEF-T transfected with STAT6 siRNA do not exhibit significantly reduced IL-13-induced contaction compared to BEF-T transfected wth a negative control siRNA.Contraction is determined by the change in the size (i.e.surface area) of the collagen gels.