title: Stem cells from human amniotic fluid exert immunoregulatory function via secreted indoleamine 2,3-dioxygenase1.
abstract: Although human amniotic fluid does contain different populations of foetal-derived stem cells, scanty information is available on the stemness and the potential immunomodulatory activity of in vitro expanded, amniotic fluid stem cells. By means of a methodology unrequiring immune selection, we isolated and characterized different stem cell types from second-trimester human amniotic fluid samples (human amniotic fluid stem cells, HASCs). Of those populations, one was characterized by a fast doubling time, and cells were thus designated as fHASCs. Cells maintained their original phenotype under prolonged in vitro passaging, and they were able to originate embryoid bodies. Moreover, fHASCs exhibited regulatory properties when treated with interferon (IFN)-γ, including induction of the immunomodulatory enzyme indoleamine 2,3-dioxygenase 1 (IDO1). On coculture with human peripheral blood mononuclear cells, IFN-γ-treated fHASCs caused significantly decreased T-cell proliferation and increased frequency in CD4(+)  CD25(+)  FOXP3(+) regulatory T cells. Both effects required an intact IDO1 function and were cell contact-independent. An unprecedented finding in our study was that purified vesicles from IFN-γ-treated fHASCs abundantly expressed the functional IDO1 protein, and those vesicles were endowed with an fHASC-like regulatory function. In vivo, fHASCs were capable of immunoregulatory function, promoting allograft survival in a mouse model of allogeneic skin transplantation. This was concurrent with the expansion of CD4(+)  CD25(+)  Foxp3(+) T cells in graft-draining lymph nodes from recipient mice. Thus fHASCs, or vesicles thereof, may represent a novel opportunity for immunoregulatory maneuvers both in vitro and in vivo.
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Romani
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Pirisinu
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Calvitti
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Pallotta
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Gargaro
authors.affiliation: Plastic Surgery Unit, Hospital Universitario de la Ribera, Valencia, Spain.|Department of Surgery, 'La Sapienza' University, Rome, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bistoni
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Carmine
authors.initials: C
authors.lastname: Vacca
authors.affiliation: Department of Physics and Geology, University of Perugia, Perugia, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Di Michele
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Ciriana
authors.initials: C
authors.lastname: Orabona
authors.affiliation: iPS-Cellular Reprogramming Unit, Fondazione Casa Sollievo della Sofferenza, Mendel, Rome, Italy.
authors.forename: Jessica
authors.initials: J
authors.lastname: Rosati
authors.affiliation: Department of Medicine, University of Perugia, Perugia, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Pirro
authors.affiliation: Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Giovagnoli
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Matino
authors.affiliation: Department of Surgery and Biomedical Sciences, University of Perugia, Perugia, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Prontera
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Rosi
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Ursula
authors.initials: U
authors.lastname: Grohmann
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Vincenzo N
authors.initials: VN
authors.lastname: Talesa
authors.affiliation: Department of Surgery and Biomedical Sciences, University of Perugia, Perugia, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Donti
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Puccetti
authors.affiliation: Department of Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Fallarino
mesh_terms: D000328:Adult; D064591:Allografts / Q000187:drug effects; D000653:Amniotic Fluid / Q000166:cytology*; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002450:Cell Communication / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002469:Cell Separation; D048430:Cell Shape / Q000187:drug effects; D002999:Clone Cells; D058732:Embryoid Bodies / Q000166:cytology; D006085:Graft Survival / Q000187:drug effects; D006801:Humans; D056747:Immunomodulation / Q000187:drug effects; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase / Q000378:metabolism*; D007371:Interferon-gamma / Q000494:pharmacology; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D010641:Phenotype; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000276:immunology
chemical_list: D015415:Biomarkers; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D007371:Interferon-gamma
keywords: T cells; cell culture; cloning; immunosuppression; lymphocytes; pluripotent stem cells