125I seed combined with DCS loaded with tumor antigen to convert irradiated liver cancer into effective in situ vaccine.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e14573-e14573
Author(s):  
Peng Zeng
Keyword(s):  
Bone Marrow ◽  
Liver Cancer ◽  
T Cell Proliferation ◽  
Abscopal Effect ◽  
Triple Combination ◽  
Local Tumor ◽  
In Situ Vaccine

e14573 Background: With unique feature of self-immune tolerance and high radio-sensitivity, hepatocellular carcinoma (HCC) can gradually develop undesired effects. Iodine-125 (125I) seed, as a source of internal radiation therapy, may have a favorable adaptability and immunostimulation. In this study, we investigated whether 125I seeds can stimulate local tumor infiltrating lymphocytes (TILs) and whether a combination of 125I seeds and dendritic cells (DCs) loaded with tumor antigen (Ag+DCs) can enhance both local tumor control and abscopal effect in murine subcutaneous tumor models. The related mechanism of anti-tumor immune response was also explored. Methods: H22/Hepa1-6 HCC cells were examined for radiosensitivity and immunosensitivity. Cell apoptosis and expression of MHC-I (major histocompatibility complex class I) and PD-L1 (programmed death-ligand 1) were detected before and after irradiation. The tumor cells were injected subcutaneously as primary and abscopal tumor. Bone marrow-derived dendritic cells (BM-DCs) were induced from mouse bone marrow cells and incubated with tumor cell lysate. 125I seeds were implanted into the primary tumors, followed by intratumoral injection of Ag+DCs and intraperitoneal injection of αPD1 antibody (αPD1-ab). DC migration was detected by transwell chambers in vitro and CFSE (carboxyfluorescein succinimidyl ester)-labeled DCs in vivo. DC maturation was tested by flow cytometry. Analyses of tumor growth and survival rates were performed in vitro, and that of, TILs, T-cell proliferation, cytotoxicity test, immunostimulatory cytokines release, and immunological memory were performed in vivo. In situ vaccine and abscopal effect were verified in orthotopic mouse models of liver cancer and lung metastatic tumor. Results: 125I seeds alone could induce TILs and activate cytotoxic T cells (CTLs), but these effects were limited. The combination treatment of 125I seeds with Ag+DC administration inhibited primary tumor growth and significantly prolonged survival time in association with a significant increase in T-cell proliferation and interferon-γ release. In addition, triple-combination treatment with αPD1-ab amplified these responses, leading to significant regression of primary and metastatic tumors and successful stimulation of immunological memory. Conclusions: 125I seeds can safely activate anti-tumor immune response.125I seeds combined with Ag+DC administration is able to convert irradiated liver cancer into effective in situ vaccine. Furthermore, triple-combination therapy of 125I seeds, Ag+DC, and αPD1-ab can be a promising approach to activate systemic anti-tumor immunity, which is a potential novel individualized therapy for patients with solid cancers.

scholarly journals The coordinated action of G-CSF and ELR + CXC chemokines in neutrophil mobilization during acute inflammation

Blood ◽  
2008 ◽  
Vol 111 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Antje M. Wengner ◽  
Simon C. Pitchford ◽  
Rebecca C. Furze ◽  
Sara M. Rankin
Keyword(s):  
Bone Marrow ◽  
Intraperitoneal Injection ◽  
Fold Increase ◽  
In Situ Perfusion ◽  
Acute Peritonitis ◽  
Femoral Bone Marrow ◽  
Prior Administration

In this study, we have identified a unique combinatorial effect of the chemokines KC/MIP-2 and the cytokine granulocyte colony-stimulating factor (G-CSF) with respect to the rapid mobilization of neutrophils from the bone marrow in a model of acute peritonitis. At 2 hours following an intraperitoneal injection of thioglycollate, there was a 4.5-fold increase in blood neutrophil numbers, which was inhibited 84% and 72% by prior administration of blocking mAbs against either the chemokines KC/MIP-2 or G-CSF, respectively. An intraperitoneal injection of G-CSF acted remotely to stimulate neutrophil mobilization, but did not elicit recruitment into the peritoneum. Further, in vitro G-CSF was neither chemotactic nor chemokinetic for murine neutrophils, and had no priming effect on chemotaxis stimulated by chemokines. Here, we show that, in vitro and in vivo, G-CSF induces neutrophil mobilization by disrupting their SDF-1α–mediated retention in the bone marrow. Using an in situ perfusion system of the mouse femoral bone marrow to directly assess mobilization, KC and G-CSF mobilized 6.8 × 106 and 5.4 × 106 neutrophils, respectively, while the infusion of KC and G-CSF together mobilized 19.5 × 106 neutrophils, indicating that these factors act cooperatively with respect to neutrophil mobilization.

scholarly journals Eotaxin Induces a Rapid Release of Eosinophils and Their Progenitors From the Bone Marrow

Blood ◽  
1998 ◽  
Vol 91 (7) ◽  
pp. 2240-2248 ◽  
Author(s):  
Roger T. Palframan ◽  
Paul D. Collins ◽  
Timothy J. Williams ◽  
Sara M. Rankin
Keyword(s):  
Bone Marrow ◽  
Guinea Pig ◽  
Allergic Inflammation ◽  
Interleukin 5 ◽  
In Situ Perfusion ◽  
Dose Dependent ◽  
Femoral Bone Marrow

The CC-chemokine eotaxin is a potent eosinophil chemoattractant that stimulates recruitment of eosinophils from the blood to sites of allergic inflammation. Mobilization from the bone marrow is an important early step in eosinophil trafficking during the allergic inflammatory response. In this paper we examine the potential of eotaxin to mobilize eosinophils and their progenitors from bone marrow. Eotaxin stimulated selective, dose-dependent chemotaxis of guinea pig bone marrow eosinophils in vitro. Intravenous injection of eotaxin (1 nmol/kg) into guinea pigs in vivo stimulated a rapid blood eosinophilia (from 3.9 ± 1.2 to 28 ± 9.9 × 104eosinophils/mL at 30 minutes) and a corresponding decrease in the number of eosinophils retained in the femoral marrow (from 9.0 ± 0.8 to 4.8 ± 0.8 × 106 eosinophils per femur). To show a direct release of eosinophils from the bone marrow an in situ perfusion system of the guinea pig femoral bone marrow was developed. Infusion of eotaxin into the arterial supply of the perfused femoral marrow stimulated a rapid and selective release of eosinophils into the draining vein. In addition, eotaxin stimulated the release of colony-forming progenitor cells. The cytokine interleukin-5 was chemokinetic for bone marrow eosinophils and exhibited a marked synergism with eotaxin with respect to mobilization of mature eosinophils from the femoral marrow. Thus, eotaxin may be involved in both the mobilization of eosinophils and their progenitors from the bone marrow into the blood and in their subsequent recruitment into sites of allergic inflammation.

scholarly journals Eotaxin Induces a Rapid Release of Eosinophils and Their Progenitors From the Bone Marrow

Blood ◽  
1998 ◽  
Vol 91 (7) ◽  
pp. 2240-2248 ◽  
Author(s):  
Roger T. Palframan ◽  
Paul D. Collins ◽  
Timothy J. Williams ◽  
Sara M. Rankin
Keyword(s):  
Bone Marrow ◽  
Guinea Pig ◽  
Allergic Inflammation ◽  
Interleukin 5 ◽  
In Situ Perfusion ◽  
Dose Dependent ◽  
Femoral Bone Marrow

Abstract The CC-chemokine eotaxin is a potent eosinophil chemoattractant that stimulates recruitment of eosinophils from the blood to sites of allergic inflammation. Mobilization from the bone marrow is an important early step in eosinophil trafficking during the allergic inflammatory response. In this paper we examine the potential of eotaxin to mobilize eosinophils and their progenitors from bone marrow. Eotaxin stimulated selective, dose-dependent chemotaxis of guinea pig bone marrow eosinophils in vitro. Intravenous injection of eotaxin (1 nmol/kg) into guinea pigs in vivo stimulated a rapid blood eosinophilia (from 3.9 ± 1.2 to 28 ± 9.9 × 104eosinophils/mL at 30 minutes) and a corresponding decrease in the number of eosinophils retained in the femoral marrow (from 9.0 ± 0.8 to 4.8 ± 0.8 × 106 eosinophils per femur). To show a direct release of eosinophils from the bone marrow an in situ perfusion system of the guinea pig femoral bone marrow was developed. Infusion of eotaxin into the arterial supply of the perfused femoral marrow stimulated a rapid and selective release of eosinophils into the draining vein. In addition, eotaxin stimulated the release of colony-forming progenitor cells. The cytokine interleukin-5 was chemokinetic for bone marrow eosinophils and exhibited a marked synergism with eotaxin with respect to mobilization of mature eosinophils from the femoral marrow. Thus, eotaxin may be involved in both the mobilization of eosinophils and their progenitors from the bone marrow into the blood and in their subsequent recruitment into sites of allergic inflammation.

Ectopic Human Mesenchymal Stem Cell-Coated Scaffolds Create An In Vivo Leukemia Niche in NOD/SCID Mice.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 559-559
Author(s):  
Sarah Rivkah Vaiselbuh ◽  
Morris Edelman ◽  
Jeffrey Michael Lipton ◽  
Johnson M. Liu
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Stem Cell Niche ◽  
Scid Mice ◽  
Cxcr4 Antagonist ◽  
Cell Niche

Abstract Abstract 559 Introduction: Different cellular components of the normal hematopoietic niche have been identified. However, the niche for malignant hematopoiesis remains to be elucidated. Recent work of other groups has suggested that hematopoietic stem cells (HSC) within the bone marrow anchor themselves in place by attaching to osteoblasts and/or vascular sinusoid endothelial cells. We have recently identified mesenchymal stem cells (MSC) as niche-maker cells and found a crucial role of the SDF-1/CXCR4 axis in this process. Stromal Derived Factor-1 (SDF-1/CXCL12) regulates stem cell trafficking and the cell cycle via its receptor CXCR4. Methods: Polyurethane scaffolds, coated in vitro with human bone marrow MSC, were implanted subcutaneously in non-irradiated NOD/SCID mice. CD34+ HSC or primary AML cells (from a leukapheresis product) were injected either in situ or retro-orbitally in the mice and analyzed for engraftment. The mice were treated twice per week with in situ injections of SDF-1, AMD3100 (a CXCR4 antagonist) or PBS (control). After 2 to 4 weeks, the scaffolds were processed and evaluated for cell survival in the mesenchymal niche by immunohistochemistry. Results: We created in vitro MSC-coated scaffolds that retained inoculated AML cells in the presence of SDF-1, while AML cells seeded on empty scaffolds were not retained. In vivo in NOD/SCID mice, the MSC-coated scaffolds, in the presence of SDF-1 enabled homing of both in situ injected normal CD34+ HSC and retroorbital- or in situ injected primary human AML cells. The scaffolds were vascularized and showed osteoclasts and adipocytes present, suggestive of an ectopic human bone marrow microenvironment in the murine host. Finally, the SDF-1-treated scaffolds showed proliferation of the MSC stromal layer with multiple adherent AML cells, while in the AMD3100-treated scaffolds the stromal lining was thin and disrupted at several points, leaving AML cells free floating in proximity. The PBS-treated control-scaffold showed a thin single cell MSC stromal layer without disruption, with few AML cells attached. Conclusion: The preliminary data of this functional ectopic human microenvironment in NOD/SCID mice suggest that AMD3100 (a CXCR4 antagonist) can disrupt the stem cell niche by modulation of the mesenchymal stromal. Further studies are needed to define the role of mesenchymal stem cells in maintaining the hematopoietic/leukemic stem cell niche in vivo. In Vivo Leukemia Stem Cell Niche: (A) Empty polyurethane scaffold. (B)Vascularization in SQ implanted MSC-coated scaffold (s) niche in NOD/SCID mice. (C) DAB Peroxidase (brown) human CD45 positive nests of AML cells (arrows) 1 week after direct in situ AML injection. (D) Human CD45 positive myeloid cells adhere to MSC in vivo (arrows). Disclosures: No relevant conflicts of interest to declare.

scholarly journals D-mannose ameliorates autoimmune phenotypes in mouse models of lupus

2020 ◽  
Author(s):  
Haiting Wang ◽  
Xiangyu Teng ◽  
Georges Abboud ◽  
Wei Li ◽  
Shuang Ye ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Cell Proliferation ◽  
T Cells ◽  
Dendritic Cells ◽  
T Cell Proliferation ◽  
Autoantibody Production ◽  
Models Of Lupus

Abstract Background: Systemic lupus erythematosus is a disorder of immune regulation characterized by overproduction of autoantibodies. D-mannose is a C-2 epimer of glucose that exhibits immunoregulatory effects in models of autoimmune diseases, such as type 1 diabetes, induced rheumatoid arthritis, and airway inflammation. This study was conducted to evaluate the efficacy of D-mannose treatment in mouse models of lupus.Methods: The effect of D-Mannose was evaluated by flow cytometry on the in vitro activation of C57BL/6 (B6) murine bone marrow derived dendritic cells and their ability to induce antigen specific CD4+ T cell proliferation and activation. The effect of D-mannose administration in vivo on the frequency of Foxp3+ regulatory T cells in B6 mice was assessed by flow cytometry. D-mannose was administered to two models of lupus: the chronic graft-versus-host disease (cGVHD) induced model and the B6.lpr spontaneous model. Autoantibody production was measured by ELISA and immune activation by flow cytometry. Results were compared by two-tailed statistics: unpaired or paired t tests, or Mann-Whitney U tests depending on whether the data was normally distributed.Results: D-mannose inhibited the maturation of bone marrow dendritic cells and their induction of antigen-specific T cell proliferation and activation in vitro. In vivo, D-mannose increased the frequency of Foxp3+ regulatory T cells in unmanipulated control mice. In the cGVHD model of induced lupus, D-mannose treatment decreased autoantibody production, with a concomitant reduction of the frequency of effector memory and follicular helper T cells as well as germinal center B cells and plasma cells. These results were partially validated in the B6.lpr model of spontaneous lupus. Conclusion: Overall, our results suggest that D-mannose ameliorates autoimmune activation in models of lupus, at least partially due to its expansion of Treg cells, the induction of immature conventional dendritic cells and the downregulation of effector T cells activation. D-Mannose showed however a weaker immunomodulatory effect in lupus than in other autoimmune diseases.

scholarly journals Tasquinimod Targets Immunosuppressive Myeloid Cells, Increases Osteogenesis and Has Direct Anti-Myeloma Effects By Inhibiting c-Myc Expression in Vitro and In Vivo

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1594-1594
Author(s):  
Rong Fan ◽  
Hatice Satilmis ◽  
Niels Vandewalle ◽  
Elke De Bruyne ◽  
Eline Menu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Cell Proliferation ◽  
T Cells ◽  
Cell Lines ◽  
Interferon Gamma ◽  
Myeloid Cells ◽  
T Cell Proliferation

Abstract Introduction Immunotherapy has revolutionized cancer treatment and significantly affected the management of Multiple Myeloma (MM) patients. Unfortunately, these immunotherapeutic approaches are hampered by the presence of a suppressive bone marrow microenvironment including myeloid derived suppressor cells and tumor associated macrophages. Tasquinimod (TasQ), an immunomodulatory compound, is currently in phase Ib/IIa for relapsed/refractory MM patients (NCT04405167). TasQ blocks the interaction between S100A9 and its receptors, which is associated with reduced MDSC accumulation. In this study, we investigated TasQ-mediated direct and indirect effects on MM cell growth, bone disease and immunomodulation in vitro and in vivo using human myeloma cell lines and the immunocompetent 5TMM models. Material and methods In vitro, murine (5T33vt, 5TGM1) and human (JJN3, LP1, OPM2, and RPMI8226) MM cell lines were cultured at different concentrations of TasQ. Cell proliferation was assessed by BrdU staining using flow cytometry. C-Myc and pSTAT3 expression were analyzed by western blot. In vitro T cell proliferation experiments were performed using MACS-sorted CD11b + cells and CFSE-labeled T cells from naïve mice. Cells were cocultured for 72h in the presence of MM conditioned medium (5T33MMvt CM) with CD3/CD28 microbeads, followed by flow cytometry to assess T cell proliferation. For in vivo experiments, we used the 5T33 (aggressive) and 5TGM1 (moderate) MM models. On the second day after tumor cell injection, the mice were randomly assigned to the treatment group and the control group. The treatment group received 30 mg/kg of TasQ in drinking water for 35 days (5TGM1) and 21 days (5T33). Anti-tumor and immunomodulating effects were analyzed by flow cytometry (e.g. tumor cells, myeloid subsets, CD4/CD8 + T cells), qRT-PCR, western blot and serum ELISA (interferon-gamma). Effects on osteogenesis in the 5TGM1 model was investigated by Micro-CT. Statistical differences were assessed by Mann-Whitney U test and One-way ANOVA with p<0.05 considered as statistically significant. Results TasQ-treatment of murine and human myeloma cell lines (HMCL), at concentrations of 10-25uM, significantly reduced MM cell proliferation after 24h and 48h in vitro (n=3, p<0.05). In addition, a downregulation in c-Myc expression could be observed 6h after treatment of human MM cell lines (n=3). In vitro, TasQ significantly increased T cell proliferation in co-culture experiments with T cells and myeloid cells in 5T33MMvt CM (n=3, p<0.05). Using the immunocompetent 5TGM1 and 5T33MM model, we investigated direct and indirect anti-tumor effects of TasQ. We found that TasQ significantly reduced tumor load in the bone marrow of 5TGM1 (n=10/group, p=0.0012) and 5T33MM mice (n=10/group, p=0.0106) compared to vehicle-treated control mice. Using flow cytometry, we could not observe a difference in the percentage of CD4 + and CD8 + T cells. However, a significant upregulation in serum interferon-gamma could be observed in the 5T33MM mice (p=0.0284). While the percentage of CD11b + cells in the TasQ-treated group was significantly increased (p<0.05), the percentage of monocytic myeloid cells (CD11b +Ly6G -) was significantly reduced in both models (p<0.05). qRT-PCR results showed that the expression of IL-10 was downregulated in purified CD11b + myeloid cells (p<0.05). Consistent with the in vitro data, we observed a decrease in the protein expression of c-Myc in purified MM cells obtained from TasQ-treated mice compared to control mice. Micro-CT analysis of femurs demonstrated a significant increase in the percentage BV/TV (ratio of bone material volume over tissue volume) and trabeculae number (p<0.0001) in TasQ-treated 5TGM1 mice compared to untreated mice. Conclusion TasQ has pleiotropic effects on the MM cells and its surrounding bone marrow microenvironment. It affects MM cell growth by decreasing c-Myc expression. In addition, TasQ targets the immunosuppressive monocytic myeloid cell population and increases serum interferon-gamma levels, indicative for immune cell activation. Moreover, it stimulates osteogenesis in vivo. Taken together, all these data provide evidence for the therapeutic benefits of TasQ as an anti-MM therapy for patients. Disclosures Törngren: Active Biotech: Current Employment. Eriksson: Active Biotech: Current Employment. De Veirman: Active Biotech AB: Research Funding.

scholarly journals D-mannose ameliorates autoimmune phenotypes in mouse models of lupus

2020 ◽  
Author(s):  
Haiting Wang ◽  
Xiangyu Teng ◽  
Georges Abboud ◽  
Wei Li ◽  
Shuang Ye ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Cell Proliferation ◽  
T Cells ◽  
Dendritic Cells ◽  
T Cell Proliferation ◽  
Autoantibody Production ◽  
Models Of Lupus

Abstract Background Systemic lupus erythematosus is a disorder of immune regulation characterized by overproduction of autoantibodies. D-mannose is a C-2 epimer of glucose that exhibits immunoregulatory effects in models of autoimmune diseases, such as type 1 diabetes, induced rheumatoid arthritis, and airway inflammation. This study was conducted to evaluate the efficacy of D-mannose treatment in mouse models of lupus. Methods The effect of D-Mannose was evaluated by flow cytometry on the in vitro activation of C57BL/6 (B6) murine bone marrow derived dendritic cells and their ability to induce antigen specific CD4+ T cell proliferation and activation. The effect of D-mannose administration in vivo on the frequency of Foxp3+ regulatory T cells in B6 mice was assessed by flow cytometry. D-mannose was administered to two models of lupus: the chronic graft-versus-host disease (cGVHD) induced model and the B6.lpr spontaneous model. Autoantibody production was measured by ELISA and immune activation by flow cytometry. Results were compared by two-tailed statistics: unpaired or paired t tests, or Mann-Whitney U tests depending on whether the data was normally distributed. Results D-mannose inhibited the maturation of bone marrow dendritic cells and their induction of antigen-specific T cell proliferation and activation in vitro. In vivo, D-mannose increased the frequency of Foxp3+ regulatory T cells in unmanipulated control mice. In the cGVHD model of induced lupus, D-mannose treatment decreased autoantibody production, with a concomitant reduction of the frequency of effector memory and follicular helper T cells as well as germinal center B cells and plasma cells. These results were partially validated in the B6.lpr model of spontaneous lupus. Conclusion Overall, our results suggest that D-mannose ameliorates autoimmune activation in models of lupus, at least partially due to its expansion of Treg cells, the induction of immature conventional dendritic cells and the downregulation of effector T cells activation. D-Mannose showed however a weaker immunomodulatory effect in lupus than in other autoimmune diseases.

scholarly journals Irisin directly stimulates osteoclastogenesis and bone resorption in vitro and in vivo

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Eben G Estell ◽  
Phuong T Le ◽  
Yosta Vegting ◽  
Hyeonwoo Kim ◽  
Christiane Wrann ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Bone Resorption ◽  
Osteoclast Differentiation ◽  
Neutralizing Antibody ◽  
Mouse Bone Marrow ◽  
Differential Gene

Irisin, a skeletal-muscle secreted myokine, facilitates muscle-bone crosstalk and skeletal remodeling in part by its action on osteoblasts and osteocytes. In this study, we investigated whether irisin directly regulates osteoclasts. In vitro, irisin (2–10 ng/mL) increased osteoclast differentiation in C57BL/6J mouse bone marrow progenitors; however, this increase was blocked by a neutralizing antibody to integrin αVβ5. Irisin also increased bone resorption on several substrates in situ. RNAseq revealed differential gene expression induced by irisin including upregulation of markers for osteoclast differentiation and resorption, as well as osteoblast-stimulating ‘clastokines’. Forced expression of the irisin precursor Fndc5 in transgenic C57BL/6J mice resulted in lower bone mass at three ages and greater in vitro osteoclastogenesis from Fndc5-transgenic bone marrow progenitors. This study demonstrates that irisin acts directly on osteoclast progenitors to increase differentiation and promote bone resorption, supporting the tenet that irisin not only stimulates bone remodeling but may also be an important counter-regulatory hormone.

Monocytic Myeloid-Derived Suppress Cells Restore Adipogenic Bone Marrow Microenvironment in Aplastic Anemia By Inhibiting Intra-BM CD8+ T Cells Proliferation

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1211-1211
Author(s):  
Ying Qu ◽  
Zhengxu Sun ◽  
Yan Yuan ◽  
Fen Wang ◽  
Kunpeng Wu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
T Cell Proliferation ◽  
Immune Balance ◽  
Ifn Γ

Aplastic anemia (AA) is a hematopoietic disorder resulted from immune-related hypocellular hematopoiesis in bone marrow (BM). It has been clearly addressed that the activated T cells contribute to the exhaustion of hematopoietic progenitors and hypo-hematopoiesis. The adipogenic BM is one of the characteristics to make AA diagnosis. However, little is known about the relationship of intra-BM immune imbalance and hematopoietic microenvironment abnormity in this disease entity. Functional hematopoiesis relies on not only abundant hematopoietic stem cells (HSCs) but also the balanced supportive hematopoietic niche. Intra-BM immune balance, at either cellular or cytokine level, is one of the key footstones to maintain hematopoietic microenvironment. Various intra-BM immune cellular components play both sides of one coin. Among them, myeloid-derived suppressive cells (MDSCs) are heterogeneous myeloid progenitor cells characterized by the negative immune response in cancers and other inflammatory diseases. In BM aspiration and biopsy samples from the patients who were diagnosed as AA in our study, massive activated lymphocytes infiltration and adipocytes accumulation were observed. Interestingly, the absolute numbers of immune modulatory MDSCs either in AA patients' PB or in BM of immune-related AA mice were reduced, indicating a potential link between polarized BM adipo-osteogenic microenvironment and immune disorder under AA circumstance. We thus adopted AA mice model to look into the embedded details both in vivo and in vitro. We clarified that BM components were more vulnerable to the attack of CD8+ T cells than that of CD4+ T cells. Taking into the fact that BM adipocytes are more abundant either in AA patients or in AA mice models, we differentiated mesenchymal stromal cells (MSCs), the major BM stroma cells, into osteoblastic or adipogenic lineages to mimic the osteo-adipogenic differentiation in BM microenvironment. Interestingly, CD8+ T cells and interferon-γ(IFN-γ) exerted dramatically adipocytic stimulation on BM-MSCs either in vitro or in vivo, by determination of increasing expression of adipogenetic genes including Ap2, Perilipin, Pparg and Cebpα, as well as staining of Oil Red O and perilipin. To dissect intra-BM cellular immune balance, MDSCs were isolated as representative immune regulating population to investigate their function on osteo-adipogenic balance. Interestingly, not CD11b+Ly6G+Ly6C-granulocytic-MDSCs (gMDSCs) but CD11b+Ly6G-Ly6C+monocytic-MDSCs (mMDSCs) inhibited both T cell proliferation and IFN-γ production. Addition of L-NMMA, the antagonist of iNOS pathway in mMDSCs-containing system restored T cell proliferative curve and cell numbers, whereas Nor-NOHA, the antagonist of Arg-1 pathway didn't abrogate mMDSCs' immune-regulation properties, indicating that mMDSCs inhibited T cell proliferation via iNOS pathway. We then performed single dose or multi-dose injection of mMDSCs in AA mice to see whether mMDSCs are able to reconstitute the impacted hematopoiesis. Single injection of mMDSCs was able to prevent from CTL infiltration in a very short term. However, multi-injection of mMDSCs showed significant benefit in overall survival rate compared to AA mice. We further detected the function of mMDSCs on polarized BM-MSCs adipo-osteogenic differentiation potential. To detect sequential BM adipogenetic progression in AA microenvironment, we performed in vivo fluorescent microscopy on AP2 (Fabp4)-Cre×mT/mG reporting mice at different transfusion time points of T cells and mMDSCs. GFP-expressing AP2+ adipocytes accumulated adjacently to perivascular niches whose boarders were labelled by Dextran-CY5 in a time-dependent manner after T cell infusion. Monocytic MDSCs transfused AA mice showed decreased GFP+ adipocytes which was coincident with our in vitro findings. In conclusion, intra-BM immune balance is one of the environmental factors seesawing by activating and suppressive ends to support functional hematopoiesis. Adoptive transfusion of mMDSCs, the immune-suppressive population might be a novel immune-regulating strategy to treat AA, relying on not only restoring the intra-BM immune balance but also improving stroma's multi-differentiating microenvironment. Figure Disclosures No relevant conflicts of interest to declare.

APRIL Provides Springtime for Antibody-Producing Plasma-Cell Lifetime

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2568-2568
Author(s):  
Bertrand Huard ◽  
Elodie Belnoue ◽  
Thomas Mc Kee ◽  
Thomas Matthes ◽  
Claire-Anne Siegrist ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Plasma Cell ◽  
Plasma Cells ◽  
Constitutive Expression ◽  
Lymphoid Tissues ◽  
Tnf Superfamily ◽  
Unique Source

Abstract Antibody-producing plasma cells depend on their environment for survival, but the molecules involved in this process are still not well defined. Plasma cells are fully equipped to respond to a proliferation inducing ligand (APRIL) from the tumor necrosis factor (TNF) superfamily, by virtue of their constitutive expression of the B-cell maturation antigen (BCMA), as canonical receptor from the TNF receptor superfamily, and the heparan sulfate proteoglycan (HSPG), CD138, as co-receptor. Here, we report that APRIL promoted the in vitro survival of plasma cells by upregulating expression of several anti-apoptotic molecules, such as bcl-2, bcl-xL and mcl-1. We further observed an in situ localization for APRIL consistent with this pro-survival role, both in mucosa-associated lymphoid tissues (MALT) and the bone marrow. In upper MALT, the tonsillar epithelium produced APRIL. Upon infection, APRIL production increased considerably when APRIL-secreting neutrophils, recruited from the blood, infiltrated the crypt epithelium. HSPG retained secreted APRIL in the sub-epithelium of the infected zone to create APRIL-rich niches, wherein IgG-producing plasma cells accumulated. In lower MALT, neutrophils were the unique source of APRIL giving rise to similar niches for IgA-producing plasmocytes in villi of lamina propria. The requirement on an inflammatory reaction in niche establishment implies that plasma-cell survival in mucosa is associated to pathogen presence, and must be short as a consequence. We observed also APRIL in the bone marrow. In this latter organ, maturating granulocytes produced constitutively APRIL. Such constitutive expression of a plasma cell pro-survival explains, at least in part, why plasma-cell longevity in the bone marrow can be so long lasting. These in situ human observations were confirmed in vivo with APRIL-deficient mice.

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