In human cutaneous leishmaniasis, increased arginase activity has been associated to chronic infections [50, 51]; in these studies, neutrophils were the enzymes main source. of Ly6C on CD11bhi Ly6Ghi neutrophils in (left panels) and mice (right panels).(TIF) ppat.1006616.s004.tif (850K) GUID:?6EBD6E9F-7A9E-4B66-BA0E-75D39E096F2D S5 Fig: Mice were infected with 2×107 LV9 amastigotes intravenously. (A) Representative histograms for total ROS production at various time points of contamination in and Cmice. (B-C) Representative FACS plots for ROS expression in Ly6Ghi neutrophils (B) and Ly6Chi monocytes (C) from (left panels) and mice (right panels).(TIF) ppat.1006616.s005.tif (576K) GUID:?8A36A7E2-84AF-4D81-BD5F-4117D43AAB4A S6 Fig: (A) Splenocytes from na?ve and infected mice (d28 p.i.) Brinzolamide were stained with hypoxyprobe and analyzed by FACS. (B) Western Blot analysis of HIF-1 expression in infected bone marrow-derived monocytes. Monocytes were derived under hypoxia for three days from the bone marrow of na?ve and amastigotes prior to activation or not with IFN. (The infection was monitored for 1h, 12h and 24h. (A) Representative FACS plots for LV9+Ly6Chi (C) and LV9+ Ly6Clow/int moncoytes (D). (TIF) ppat.1006616.s006.tif (632K) GUID:?C0EF5918-E7F8-4F84-A529-CE48495BFDA9 S7 Fig: Monocytes were derived under hypoxia for three days from the bone marrow of na?ve and amastigotes prior to activation or not with IFN; M-CSF was kept in the medium. The infection was monitored for 12 and 24h. Representative FACS plots for LV9+Ly6Chi (A) and Brinzolamide LV9+ Ly6Clow/int moncoytes (B).(TIF) ppat.1006616.s007.tif (819K) GUID:?51CBA368-7559-482E-AECF-87935C15E5E9 S8 Fig: Real-time PCR analysis of mRNA expression levels in splenic CD11c+ cells purified from infected and mice at various time points after infection. (TIF) ppat.1006616.s008.tif (179K) GUID:?4A21218E-4A56-4746-A547-321150F084A2 Data Availability StatementAll relevant data are within the paper and its Supporting Information files. Abstract is known to induce myelopoiesis and to dramatically increase extramedullary myelopoiesis. This results in splenomegaly, which is usually then accompanied by disruption of the splenic microarchitecture, a chronic inflammatory environment, and immunosuppression. Chronically inflamed tissues are typically hypoxic. The role of hypoxia on myeloid cell functions during visceral leishmaniasis has not yet been studied. Here we show that promotes the output from the bone marrow of monocytes with a regulatory phenotype that function as safe targets for the parasite. We also demonstrate that splenic myeloid cells acquire MDSC-like function in a HIF-1-dependent manner. HIF-1 is also involved in driving the polarization towards M2-like macrophages and Brinzolamide rendering intermediate stage monocytes more susceptible to contamination. Our results suggest that HIF-1 is usually a major player in the establishment of chronic contamination and is crucial for enhancing immunosuppressive functions and lowering leishmanicidal capacity of myeloid cells. Author summary The protozoan parasite causes chronic contamination in the spleen, which is usually accompanied by a chronic inflammatory environment, an enlargement of the organ, and immunosuppression. The environment of chronically inflamed tissues is usually characterized by low oxygen levels and tissue disruption, which induce the expression of the transcription factor HIF-1 in all cells. The kinetics of monocyte production and differentiation in the bone marrow and the spleen, and the role of hypoxia in myeloid cell functions during visceral leishmaniasis have not yet been studied. Here we show that promotes the output from the bone marrow of monocytes with a regulatory phenotype that function as safe targets for the parasite. We also demonstrate that HIF-1 potentiates inhibitory functions of myeloid cells and is involved in driving the polarization towards Foxo1 M2-like macrophages and rendering them more susceptible to contamination. Our results suggest that HIF-1 is usually a major player in the establishment of chronic contamination and is crucial for enhancing immunosuppressive functions and lowering leishmanicidal capacity of myeloid cells. Introduction Elimination of intracellular pathogens requires the induction of pro-inflammatory cytokines and.