scholarly journals In Vitro 3D Staphylococcus aureus Abscess Communities Induce Bone Marrow Cells to Expand into Myeloid-Derived Suppressor Cells

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1446
Author(s):  
Marloes I. Hofstee ◽  
Anja Heider ◽  
Sonja Häckel ◽  
Caroline Constant ◽  
Martijn Riool ◽  
...  

Staphylococcus aureus is the main causative pathogen of subcutaneous, bone, and implant-related infections, forming structures known as staphylococcal abscess communities (SACs) within tissues that also contain immunosuppressive myeloid-derived suppressor cells (MDSCs). Although both SACs and MDSCs are present in chronic S. aureus infections, it remains unknown whether SACs directly trigger MDSC expansion. To investigate this, a previously developed 3D in vitro SAC model was co-cultured with murine and human bone marrow cells. Subsequently, it was shown that SAC-exposed human CD11blow/− myeloid cells or SAC-exposed murine CD11b+ Gr-1+ cells were immunosuppressive mainly by reducing absolute CD4+ and CD8α+ T cell numbers, as shown in T cell proliferation assays and with flow cytometry. Monocytic MDSCs from mice with an S. aureus bone infection also strongly reduced CD4+ and CD8α+ T cell numbers. Using protein biomarker analysis and an immunoassay, we detected in SAC–bone marrow co-cultures high levels of GM-CSF, IL-6, VEGF, IL-1β, TNFα, IL-10, and TGF-β. Furthermore, SAC-exposed neutrophils expressed Arg-1 and SAC-exposed monocytes expressed Arg-1 and iNOS, as shown via immunofluorescent stains. Overall, this study showed that SACs cause MDSC expansion from bone marrow cells and identified possible mediators to target as an additional strategy for treating chronic S. aureus infections.

Author(s):  
Caio César Barbosa Bomfim ◽  
Eduardo Pinheiro Amaral ◽  
Igor Santiago-Carvalho ◽  
Gislane Almeida Santos ◽  
Érika Machado Salles ◽  
...  

Abstract Background The role of myeloid-derived suppressor cells (MDSCs) in severe tuberculosis patients who suffer from uncontrolled pulmonary inflammation caused by hypervirulent mycobacterial infection remains unclear. Methods This issue was addressed using C57BL/6 mice infected with highly virulent Mycobacterium bovis strain MP287/03. Results CD11b +GR1 int population increased in the bone marrow, blood and lungs during advanced disease. Pulmonary CD11b +GR1 int (Ly6G intLy6C int) cells showed granularity similar to neutrophils and expressed immature myeloid cell markers. These immature neutrophils harbored intracellular bacilli and were preferentially located in the alveoli. T cell suppression occurred concomitantly with CD11b +GR1 int cell accumulation in the lungs. Furthermore, lung and bone-marrow GR1 + cells suppressed both T cell proliferation and IFN-γ production in vitro. Anti-GR1 therapy given when MDSCs infiltrated the lungs prevented expansion and fusion of primary pulmonary lesions and the development of intragranulomatous caseous necrosis, along with increased mouse survival and partial recovery of T cell function. Lung bacterial load was reduced by anti-GR1 treatment, but mycobacteria released from the depleted cells proliferated extracellularly in the alveoli, forming cords and clumps. Conclusions Granulocytic MDSCs massively infiltrate the lungs during infection with hypervirulent mycobacteria, promoting bacterial growth and the development of inflammatory and necrotic lesions, and are promising targets for host-directed therapies.


2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi92-vi93
Author(s):  
Gregory Takacs ◽  
Christian Kreiger ◽  
Defang Luo ◽  
Joseph Flores-Toro ◽  
Loic Deleyrolle ◽  
...  

Abstract INTRODUCTION Mounting evidence suggests infiltrating immune-suppressive cells contribute to immune checkpoint inhibitor resistance and poor survival in Glioblastoma (GBM) patients. We have previously shown glioma-associated monocytic-myeloid derived suppressor cells (M-MDSCs) express chemokine receptors CCR2 and CX3CR1. Genetic and pharmacologic targeting of CCR2 promoted sequestration of M-MDSCs in the bone marrow and, in combination with PD-1 blockade, slowed progression of KR158 and 005GSC murine gliomas. This combination treatment also enhanced infiltration of IFNg-producing T cells that were less exhausted. Although CCR2+/CX3CR1+ cells display surface markers indicative of bone marrow-derived M-MDSCs, additional studies are needed to formally establish the source of these cells and to determine if they exhibit an immune-suppressive phenotype as well as migrate to the CCR2 ligands, CCL2 and/or CCL7. OBJECTIVE Evaluate the source, migration, and immune suppressive function of CCR2+/CX3CR1+ myeloid cells from glioma bearing mice. METHODS To identify the source of CCR2+/CX3CR1+ myeloid cells, chimeric wild type mice harboring bone marrow cells from transgenic CCR2WT/RFP/CX3CR1WT/GFP mice were generated. CCR2+/CX3CR1+ cells were enriched from bone marrow obtained from either wild-type or CCR2WT/RFP/CX3CR1WT/GFP naïve and glioma-bearing mice in order to evaluate their immune suppressive phenotype and ability to migrate to CCL2 and CCL7. RESULTS CCR2+/CX3CR1+ cells are present in glioma isolates from chimeric mice, indicative of a bone marrow-derived cell population, and are detectable within the tumor microenvironment as early as 3 days post orthotopic implantation of KR158 cells; these cells accumulate as tumors increase in size (r=0.7605, p=0.007). CCR2+/CX3CR1+ M-MDSCs isolated from the bone marrow of tumor bearing mice suppress CD8+ T cell production of IFNg and migrate to CCL2 more efficiently than CCL7. CONCLUSION CCR2+/CX3CR1+ cells from glioma bearing mice are derived from the bone marrow and represent an immune suppressive population that migrates to CCL2.


Blood ◽  
1981 ◽  
Vol 57 (3) ◽  
pp. 491-496
Author(s):  
A Bacigalupo ◽  
M Podesta ◽  
MC Mingari ◽  
L Moretta ◽  
G Piaggio ◽  
...  

T cells were derived from the bone marrow of 8 healthy donors and fractionated, according to their receptors for the Fc fragment of IgG, into TG+ and TG- lymphocytes. These were then cocultured with autologous or allogeneic bone marrow cells in agar in the CFU-C assay. No significant suppresion of colony formation could be detected. Total T, TG+, and TG- cells were then incubated for 18 hr with PWM, washed, and cocultured with bone marrow cells. PWM-treated TG- cells showed no significant CFU-C suppressor activity, whereas PWM-treated total T and TG+ cells inhibited colony formation of both autologous and allogeneic marrow cells. The supernatant of PWM-treated total T and TG+ cells also inhibited colony formation. PWM alone enhanced colony formation. The results of this study indicate that normal T cells can be activated in vitro to become CFU-C/suppressor cells after PWM stimulation, and that this effect is mediated by T cells with the Fc receptor for IgG.


Blood ◽  
1981 ◽  
Vol 57 (3) ◽  
pp. 491-496 ◽  
Author(s):  
A Bacigalupo ◽  
M Podesta ◽  
MC Mingari ◽  
L Moretta ◽  
G Piaggio ◽  
...  

Abstract T cells were derived from the bone marrow of 8 healthy donors and fractionated, according to their receptors for the Fc fragment of IgG, into TG+ and TG- lymphocytes. These were then cocultured with autologous or allogeneic bone marrow cells in agar in the CFU-C assay. No significant suppresion of colony formation could be detected. Total T, TG+, and TG- cells were then incubated for 18 hr with PWM, washed, and cocultured with bone marrow cells. PWM-treated TG- cells showed no significant CFU-C suppressor activity, whereas PWM-treated total T and TG+ cells inhibited colony formation of both autologous and allogeneic marrow cells. The supernatant of PWM-treated total T and TG+ cells also inhibited colony formation. PWM alone enhanced colony formation. The results of this study indicate that normal T cells can be activated in vitro to become CFU-C/suppressor cells after PWM stimulation, and that this effect is mediated by T cells with the Fc receptor for IgG.


2011 ◽  
Vol 129 (11) ◽  
pp. 2662-2673 ◽  
Author(s):  
Qiaofei Liu ◽  
Miaomiao Zhang ◽  
Xingran Jiang ◽  
Zhiqian Zhang ◽  
Lingyun Dai ◽  
...  

2017 ◽  
Vol 114 (5) ◽  
pp. 1117-1122 ◽  
Author(s):  
Victor Prima ◽  
Lyudmila N. Kaliberova ◽  
Sergey Kaliberov ◽  
David T. Curiel ◽  
Sergei Kusmartsev

In recent years, it has been established that programmed cell death protein ligand 1 (PD-L1)–mediated inhibition of activated PD-1+T lymphocytes plays a major role in tumor escape from immune system during cancer progression. Lately, the anti–PD-L1 and –PD-1 immune therapies have become an important tool for treatment of advanced human cancers, including bladder cancer. However, the underlying mechanisms of PD-L1 expression in cancer are not fully understood. We found that coculture of murine bone marrow cells with bladder tumor cells promoted strong expression of PD-L1 in bone marrow–derived myeloid cells. Tumor-induced expression of PD-L1 was limited to F4/80+macrophages and Ly-6C+myeloid-derived suppressor cells. These PD-L1–expressing cells were immunosuppressive and were capable of eliminating CD8 T cells in vitro. Tumor-infiltrating PD-L1+cells isolated from tumor-bearing mice also exerted morphology of tumor-associated macrophages and expressed high levels of prostaglandin E2(PGE2)-forming enzymes microsomal PGE2synthase 1 (mPGES1) and COX2. Inhibition of PGE2formation, using pharmacologic mPGES1 and COX2 inhibitors or genetic overexpression of PGE2-degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH), resulted in reduced PD-L1 expression. Together, our study demonstrates that the COX2/mPGES1/PGE2pathway involved in the regulation of PD-L1 expression in tumor-infiltrating myeloid cells and, therefore, reprogramming of PGE2metabolism in tumor microenvironment provides an opportunity to reduce immune suppression in tumor host.


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