Supplementary Materialsdata_sheet_1. Our data show that myeloid progenitor cells acquire T cell suppressive activity using an IFN-CSTAT1CiNOS pathway. Materials and Methods Mice C57BL/6 LCI-699 (Osilodrostat) mice were purchased from Shanghai Laboratory Animal Center, Chinese Academy Rabbit polyclonal to PDCD6 of Science (Shanghai, China). IFN-?/? (B6.129S7-IFN-tm1Ts/J), IFN-R1?/? (B6.129S7-Ifngr1tm1Agt/J), OT-II transgenic (B6.Cg-Tg (TcraTcrb) 425Cbn/J), H2Ab1?/? (B6.129S2-HSPC Culture 5??104/well WT or IFN-R?/? (GRKO) myeloid progenitor cells were cocultured with 5??104/well WT or GKO OT-II T cells in the presence of Con A (2?g/ml) for 24?h. For IFN- stimulation assay, 5??104/well WT, GRKO, or STAT1?/? myeloid progenitor cells were cultured in the presence of 20?ng/ml IFN- for 24?h. Cells were cultured in T cell medium [RPMI 1640 (Gibco, Waltham, MA, USA) supplemented with 10% FBS (Millipore), 2?mM l-glutamine (Gibco), 1?mM sodium pyruvate (Gibco), 25?mM HEPES-free acid (Gibco), 55?M 2-mercaptoethanol (Gibco), and 100?U/ml Penicillin/Streptomycin (Hyclone)] in a 96-well round bottom plate (Corning, NY, USA). After culture, dead cells were excluded by DAPI staining and phenotype of HSPCs was analyzed by flow cytometry. T LCI-699 (Osilodrostat) Cell Suppression For antigen-specific suppression assays, 1??104/well HSPCs from mice treated with Con A for 24?h or WT myeloid cells were cocultured with 5??104/well carboxyfluorescein succinimidyl ester (CFSE) (2?M, Life Technologies, Waltham, MA, USA) labeled OT-II or GKO OT-II T cells for 72?h, in the presence of 1?g/ml Ovalbumin peptide 323C339 (OVA323C339) (Sigma-Aldrich), and 1??104/well B cells as supporters. To evaluate the suppressive ability of HSPCs, the number of WT myeloid progenitors or Con A LSK cells was reduced at different gradient as HSPC:T?=?1:5/10/20/50. HSPCs and LSK cells were from BM unless indicated. PD-L1 blockade antibody (10F.9G2, Biolegend, 5?g/ml) was used to block PD-L1-PD-1 signaling (16), and LEAF? Purified IgG2b, (Biolegend) antibody was used as isotype control. In some experiments, HSPCs were treated with 25?g/ml Mitomycin C (Sigma) for 30?min at 37C and washed for at least five times before adding to the coculture system; Mitomycin C-treated B cells were utilized as control. For blended proliferation test, 5??104/very well non-CFSE-labeled OT-II T cells had been added in to the coculture program of WT myeloid progenitors and GKO OT-II LCI-699 (Osilodrostat) T cells, while 5??104/well non-CFSE-labeled GKO OT-II T cells had been added as control. Proliferation of CFSE+/lo GKO OT-II T cells was examined. Cells had been cultured in T cell moderate. After culture, useless cells were excluded by DAPI T and staining cell proliferation was assessed by CFSE dilution of B220?CD4+ cells. Percentage of proliferation was normalized with the control program. HSPC Differentiation and Proliferation Assay 5??104/well CFSE-labeled WT myeloid progenitor cells were cocultured with 5??104/well non-CFSE-labeled WT or GKO OT-II T cells in the presence of 1?g/ml OVA323C339 for 24/48/72?h. Proliferation and differentiation of HSPCs was evaluated by CFSE dilution and CD11b/Gr-1 expression of DAPI?B220?CD4? cells. Nitric Oxide Inhibition Representative nitric oxide synthase (NOS) inhibitors (Beyotime, Jiangsu, China) including l-NMMA (Pan NOS inhibitor, 200?M), 1,400?W (iNOS inhibitor, 100?M), and L-NAME (eNOS inhibitor, 100?M) were used in T cell suppression experiments to inhibit the generation of NO. Transwell Assay For transwell assays, 2.5??105 CFSE-labeled OT-II T cells and 5??104 B cells with or without 5??104 WT myeloid progenitors were cultured in the top or bottom chamber of Corning Transwell-96 System (0.4?m PC membrane, corning, NY, USA) for 3?days in the presence of 1?g/ml OVA323C339 peptide. Cells were collected respectively and proliferation of DAPI?CD4+T cells was analyzed by CFSE dilution. Cytometric Bead Array Concentrations of IFN- in serum from acute hepatitis mice/control mice were measured with a cytometric bead array kit (Mouse Th1/Th2/Th17 CBA kit, BD Biosciences) and analyzed using a FACS Verse flow cytometer with CBA software (BD Biosciences). Giemsa Staining 1??104 purified HSPCs were centrifuged on a cover glass in Cytocentrifuge Hettich Universal 32 (Hettich, Tuttlingen, Germany), followed by Wright-Giemsa Staining (SolarBio, Beijing, China). Western Blotting 3??105 purified HSPCs were lysed in sample buffer [50?mM TrisCHCl, pH 7.4, 0.15?mM Bromophenol.