title: Human multipotent mesenchymal stromal cells inhibit proliferation of PBMCs independently of IFNgammaR1 signaling and IDO expression.
abstract: Multipotent mesenchymal stromal cells (MSCs) inhibit proliferation, helper, and effector functions in most if not all peripheral blood mononuclear cell (PBMC) subpopulations in vitro. The molecular mechanism is widely thought to imply tryptophan degradation by the interferon-gamma (IFNgamma)-induced expression of indoleamine 2,3-dioxygenase (IDO). However, IDO inhibitors were not able to restore proliferation of PBMCs in each case. Moreover, human MSCs with an IFNgamma receptor 1 (R1) defect inhibited proliferation of HLA-mismatched PBMCs to a similar extent as control MSCs. In contrast to healthy MSCs, IFNgammaR1-deficient MSCs showed no detectable mRNA for IDO-neither in the absence nor in the presence of recombinant human IFNgamma, nor in coculture with HLA-mismatched PBMCs. Based on gene expression profiling, we were able to show that insulin-like growth factor (IGF)-binding proteins contribute to the inhibitory mechanism of MSCs. Taken together, human MSCs exert important immunomodulatory functions in the absence of IFNgammaR1 signaling and IDO, partially accounted for by IGF-binding proteins.
authors.affiliation: University Children's Hospital, Department of General Pediatrics, Hematology and Oncology, Tübingen, Germany.
authors.forename: Friederike
authors.initials: F
authors.lastname: Gieseke
authors.forename: Burkhardt
authors.initials: B
authors.lastname: Schütt
authors.forename: Susanne
authors.initials: S
authors.lastname: Viebahn
authors.forename: Ewa
authors.initials: E
authors.lastname: Koscielniak
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Friedrich
authors.forename: Rupert
authors.initials: R
authors.lastname: Handgretinger
authors.forename: Ingo
authors.initials: I
authors.lastname: Müller
mesh_terms: D049109:Cell Proliferation; D002478:Cells, Cultured; D002648:Child; D002846:Chromatography, Affinity; D006801:Humans; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase / Q000378:metabolism*; D018969:Insulin-Like Growth Factor Binding Proteins / Q000378:metabolism; D007371:Interferon-gamma / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D039902:Multipotent Stem Cells / Q000378:metabolism*; D017471:Receptors, Interferon / Q000378:metabolism*; D015398:Signal Transduction; D017154:Stromal Cells / Q000378:metabolism*; D000096743:Interferon gamma Receptor
chemical_list: D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D018969:Insulin-Like Growth Factor Binding Proteins; D007371:Interferon-gamma; D017471:Receptors, Interferon; D000096743:Interferon gamma Receptor