title: Mesenchymal Stem Cells Reduce Colitis in Mice via Release of TSG6, Independently of Their Localization to the Intestine.
abstract: OBJECTIVE
  Mesenchymal stem cells (MSCs) are pluripotent cells that can promote expansion of immune regulatory cells and might be developed for the treatment of immune disorders, including inflammatory bowel diseases. MSCs were reported to reduce colitis in mice; we investigated whether MSC localization to the intestine and production of paracrine factors, including tumor necrosis factor-induced protein 6 (TSG6), were required for these effects.
  
  
  METHODS
  MSCs were isolated from bone marrow (BM-MSCs) of 4- to 6-week-old C57BL/6, C57BL/6-green fluorescent protein, or Balb/c Tsg6-/- male mice. Colitis was induced by ad libitum administration of dextran sulfate sodium for 10 days; after 5 days the mice were given intraperitoneal injections of BM-MSCs or saline (controls). Blood samples and intestinal tissues were collected 24, 48, 96, and 120 hours later; histologic and flow cytometry analyses were performed.
  
  
  RESULTS
  Injection of BM-MSCs reduced colitis in mice, increasing body weight and reducing markers of intestinal inflammation, compared with control mice. However, fewer than 1% of MSCs reached the inflamed colon. Most of the BM-MSCs formed aggregates in the peritoneal cavity. The aggregates contained macrophages and B and T cells, and produced immune-regulatory molecules including FOXP3, interleukin (IL)10, transforming growth factor-β, arginase type II, chemokine (C-C motif) ligand 22 (CCL22), heme oxygenase-1, and TSG6. Serum from mice given BM-MSCs, compared with mice given saline, had increased levels of TSG6. Injection of TSG6 reduced the severity of colitis in mice, along with the numbers of CD45+ cells, neutrophils and metalloproteinase activity in the mucosa, while increasing the percentage of Foxp3CD45+ cells. TSG6 injection also promoted the expansion of regulatory macrophages that expressed IL10 and inducible nitric oxide synthase, and reduced serum levels of interferon-γ, IL6, and tumor necrosis factor. Tsg6-/- MSCs did not suppress the mucosal inflammatory response in mice with colitis.
  
  
  CONCLUSIONS
  BM-MSCs injected into mice with colitis do not localize to the intestine but instead form aggregates in the peritoneum where they produce immunoregulatory molecules, including TSG6, that reduce intestinal inflammation. TSG6 is sufficient to reduce intestinal inflammation in mice with colitis.
authors: Inflammatory Bowel Disease Center, Humanitas Clinical and Research Center, Milan, Italy.
authors: Emanuela
authors: E
authors: Sala
authors: Inflammatory Bowel Disease Center, Humanitas Clinical and Research Center, Milan, Italy.
authors: Marco
authors: M
authors: Genua
authors: Inflammatory Bowel Disease Center, Humanitas Clinical and Research Center, Milan, Italy.
authors: Luciana
authors: L
authors: Petti
authors: Department of Immunology, Humanitas Clinical and Research Center, Milan, Italy.
authors: Achille
authors: A
authors: Anselmo
authors: Department of Pathology, Catholic University of Rome, Rome, Italy.
authors: Vincenzo
authors: V
authors: Arena
authors: Department of Immunology, Humanitas Clinical and Research Center, Milan, Italy.
authors: Javier
authors: J
authors: Cibella
authors: Department of Immunology, Humanitas Clinical and Research Center, Milan, Italy.
authors: Lucia
authors: L
authors: Zanotti
authors: Inflammatory Bowel Disease Center, Humanitas Clinical and Research Center, Milan, Italy.
authors: Silvia
authors: S
authors: D'Alessio
authors: Internal Medicine, Gastroenterology Division, Catholic University of the Sacred Heart, Rome, Italy.
authors: Franco
authors: F
authors: Scaldaferri
authors: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors: Giovanni
authors: G
authors: Luca
authors: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors: Iva
authors: I
authors: Arato
authors: Department of Medicine, University of Perugia, Perugia, Italy.
authors: Riccardo
authors: R
authors: Calafiore
authors: Institute of General Pathology, Catholic University of the Sacred Heart, Rome, Italy.
authors: Alessandro
authors: A
authors: Sgambato
authors: Clinical Research Center, Division of Translational Medicine, Sidra Medical & Research Center, Doha, Qatar.
authors: Sergio
authors: S
authors: Rutella
authors: Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy.
authors: Massimo
authors: M
authors: Locati
authors: Inflammatory Bowel Disease Center, Humanitas Clinical and Research Center, Milan, Italy.
authors: Silvio
authors: S
authors: Danese
authors: Inflammatory Bowel Disease Center, Humanitas Clinical and Research Center, Milan, Italy; Department of Biomedical Sciences, Humanitas University, Milan, Italy. Electronic address: stefania.vetrano@humanitasresearch.it.
authors: Stefania
authors: S
authors: Vetrano
mesh_terms: D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D003092:Colitis / Q000628:therapy*; D016207:Cytokines / Q000378:metabolism; D016264:Dextran Sulfate; D004195:Disease Models, Animal; D007422:Intestines / Q000276:immunology; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods*; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D016896:Treatment Outcome
chemical_list: D015815:Cell Adhesion Molecules; D016207:Cytokines; C513057:Tnfaip6 protein, mouse; D016264:Dextran Sulfate
keywords: Experimental Models of Colitis; IBD; Immune Regulation; Mesenchymal Stem Cell-Based Therapy