Immunomodulatory Effects of MSC-Derived ExtracellularVesicles in Celiac Disease

Coeliac disease (CeD) is the most frequent chronic enteropathy, in which intestinal lesions are caused by a dysregulated immune response to gluten proteins. We aimed to investigate whether extracellular vesicles (EVs) from mesenchymal stem cells (MSC) exert immunomodulatory effects in experimental models of CeD and are potentially useful to treat CeD. A population of MSCs was obtained from bone marrow blood of adult healthy donors. EVs were purified by ultracentrifugation of MSC-supernatants and characterized in terms of size, protein content and expression of surface markers. The immunomodulatory effects of MSC-EVs were evaluated in vitro on gliadin-specific T-cell lines by detection of interferon (IFN)-γ production and ex vivo by using duodenal mucosa biopsies by measuring lymphocyte infiltration (CD3 and CD25 positive cells), IFN-γ and interleukin (IL)-10 secretion. Moreover, the MSC-EVs effects on B-cells in terms of HLA-DQ/DR and CD83/CD86 expression upon antigen stimulation was also evaluated. EVs obtained from non-celiac adult fibroblasts were used as controls. A significant and dose-dependent reduction of IFN-γ production by T cells in response to gliadin stimulation was observed in the presence of MSC-EVs (p < 0.05), but not with fibroblast-EVs. No modification of the expression of HLA class II molecules and costimulatory CD83 and CD86 markers on B cells upon EV-MSC incubation was found at any tested dose. Moreover, EVs from both MSCs and fibroblasts inhibited the gliadin-induced expansion of CD3+ and CD25+ T cells in organ cultures (p < 0.05), while increasing the IL-10 production (p < 0.05) and reducing IFN-γ (p = n.s) in organ supernatants. MSC- EVs modulated selected components of the immune response to gliadin in experimental models of CeD, including antigen-induced IFN-γ production and cellular responses in intestinal organ cultures. The effects observed in organ cultures were not exclusive to MSC-EVs, as EVs from fibroblast also modulated cellular responses. These findings provide a rationale for further preclinical investigation of EV-mediated immunomodulation in CeD.