Macrophage Polarization and Acquired Resistance to Rituximab in CNS Lymphoma.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3749-3749
Author(s):  
Cigall Kadoch ◽  
Valerie D. Wong ◽  
Tara Rambaldo ◽  
William Hyun ◽  
Clifford Lowell ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Macrophage Polarization ◽  
Acquired Resistance ◽  
Fold Increase ◽  
Cns Lymphoma ◽  
M2 Macrophage ◽  
M2 Macrophages ◽  
Non Hodgkin Lymphoma ◽  
Macrophage Subpopulations ◽  
M2 Phenotype

Abstract Abstract 3749 Poster Board III-685 Macrophages are a critical component of anti-tumor immunity but may be subverted from the classically-activated, or M1 phenotype, which mediates tumor elimination, to an alternatively-activated, M2 phenotype, which promotes tumor progression. Interleukin-4 (IL-4) signaling is a pivotal regulator of macrophage polarization to the M2 phenotype. The efficacy of rituximab appears to be mediated predominantly by antibody-dependent cellular cytotoxicity (ADCC) with tumor-associated macrophages being the dominant effector cell. We hypothesize that the phenotype of tumor-associated macrophages (M1 vs. M2) may be a potential determinant of rituximab efficacy or resistance. Relevant to this hypothesis is our demonstration of the intratumoral expression of IL-4 by CNS lymphoma (Blood, 2006; Clin Cancer Res., 2009) as well as our observation that the M2 polarization of macrophages by IL-4 treatment in vitro (18 h) results in an 8-fold decrease in rituximab-mediated ADCC of Raji lymphoma cells compared to ADCC-mediated by naïve or M1 polarized macrophages (p<0.001). There is an extreme paucity of molecular information regarding the role and phenotype of tumor macrophages in non-Hodgkin lymphoma in general, including CNS lymphoma. While macrophages from the cerebrospinal fluid (CSF) are routinely quantified in cytospin analyses, to date there is no established information regarding the phenotype and state of differentiation of macrophages within the leptomeningeal compartment. We have developed a novel flow-cytometry-based protocol for the isolation and phenotypic characterization of macrophages from the CSF of patients with CNS lymphoma. We have used candidate markers of M2 differentiation based upon our gene expression studies of CD14+ activated CSF macrophages, including CD206 and Factor XIII (each of which have previously been shown to be induced in macrophages upon IL-4 stimulation). We have identified M1 differentiation of CSF CD14+ macrophages by high fluorescence when incubated with DAF-FM diacetate, a cell-permeable marker of nitric oxide synthase (iNOS). Using flow-cytometry to evaluate the relative expression of DAF-FM and CD206, we demonstrate the presence of at least four subpopulations of activated macrophages in the CSF of CNS lymphoma patients. M1 macrophages, which highly express iNOS are denoted as DAF-FM(+)/CD206(-). M2 macrophages, which weakly express iNOS but which highly express CD206 are denoted as DAF-FM (-)/CD206(+). In addition, we have detected a mixed phenotype with features of both M1 and M2 macrophages, DAF-FM(+)/CD206(+), which we have termed dual-activated. A fourth subpopulation of activated macrophages within the CSF do not express iNOS or CD206. Thus far, CSF macrophage subpopulations have been characterized and sorted from thirty-five subjects: 18 patients with CNS lymphoma and 17 control subjects with non-neoplastic conditions. We demonstrate for the first time the association of M2 macrophages within the CSF with the pathogenesis of CNS lymphoma: there was a greater than six-fold increase in the proportion of macrophages with M2 features in immunocompetent subjects with CNS lymphoma compared to controls (p<0.001). By contrast, the proportion of macrophages with M1 features was similar between lymphoma and controls. In addition, we reproducibly detected an increase in the ratio of M1:M2 macrophages which correlated with therapeutic response to intrathecal methotrexate or cytarabine (within 94 h) in CNS lymphoma patients. By contrast, the intraventricular administration of rituximab was reproducibly associated with a greater than three-fold increase in the relative ratio of M2:M1 macrophages which was sustained compared to macrophages analyzed pre-intrathecal rituximab (p<0.001). In each of four cases, increases in M2 macrophage polarization anticipated the onset of intrathecal rituximab resistance and tumor progression. We believe this to be the first application of flow-cytometry to define the polarization states of intratumoral macrophages in non-Hodgkin lymphoma as well as the first description of dynamic changes in macrophage phenotypes during the evolution of resistance to rituximab therapy. The elucidation of distinct macrophage subpopulations based upon the expression of candidate markers of M1 vs. M2 phenotype may provide insight into tumor pathogenesis and prognosis. Disclosures: Off Label Use: While we describe the use of intrathecal administration of rituximab in patients with recurrent CNS and intraocular lymphomaa, the focus of our study is on the relationship between M2 macrophage polarization and the pathogenesis of CNS lymphoma as well as the potential relationship of macrophage polarization to acquired resistance to rituximab in CNS lymphoma patients.

scholarly journals Lung Tumor Cell-Derived Exosomes Promote M2 Macrophage Polarization

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1303 ◽  
Author(s):  
Alexandra Pritchard ◽  
Sultan Tousif ◽  
Yong Wang ◽  
Kenneth Hough ◽  
Saad Khan ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Tumor Cells ◽  
Bone Marrow Cells ◽  
Lung Tumor ◽  
Macrophage Polarization ◽  
M2 Macrophage ◽  
M2 Macrophages ◽  
M2 Macrophage Polarization ◽  
The Impact ◽  
M2 Phenotype

Cellular cross-talk within the tumor microenvironment (TME) by exosomes is known to promote tumor progression. Tumor promoting macrophages with an M2 phenotype are suppressors of anti-tumor immunity. However, the impact of tumor-derived exosomes in modulating macrophage polarization in the lung TME is largely unknown. Herein, we investigated if lung tumor-derived exosomes alter transcriptional and bioenergetic signatures of M0 macrophages and polarize them to an M2 phenotype. The concentration of exosomes produced by p53 null H358 lung tumor cells was significantly reduced compared to A549 (p53 wild-type) lung tumor cells, consistent with p53-mediated regulation of exosome production. In co-culture studies, M0 macrophages internalized tumor-derived exosomes, and differentiated into M2 phenotype. Importantly, we demonstrate that tumor-derived exosomes enhance the oxygen consumption rate of macrophages, altering their bioenergetic state consistent with that of M2 macrophages. In vitro co-cultures of M0 macrophages with H358 exosomes demonstrated that exosome-induced M2 polarization may be p53 independent. Murine bone marrow cells and bone marrow-derived myeloid-derived suppressor cells (MDSCs) co-cultured with lewis lung carcinoma (LLC)-derived exosomes differentiated to M2 macrophages. Collectively, these studies provide evidence for a novel role for lung tumor-exosomes in M2 macrophage polarization, which then offers new therapeutic targets for immunotherapy of lung cancer.

Dynamic Changes in Macrophage Polarization Correlate with Progression and Response in CNS Lymphoma: Insights Into the Transcriptome of Lymphoma-Associated M2 Macrophages,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3219-3219
Author(s):  
Cigall Kadoch ◽  
Valerie Wong ◽  
Lingjing Chen ◽  
Anna Bet-Lachin ◽  
Ritu Roy ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Transcriptional Profiling ◽  
Macrophage Polarization ◽  
Cns Lymphoma ◽  
M2 Macrophages ◽  
Activated Macrophages ◽  
M2 Polarization ◽  
Macrophage Subpopulations ◽  
Cns Lymphomas ◽  
Profiling Analysis

Abstract Abstract 3219 Background: Macrophages are an important component of the tumor microenvironment and the immune response to malignancy. Classically activated (M1-polarized) macrophages exhibit anti-tumor effect, while alternatively activated (M2-polarized) macrophages promote tissue repair, angiogenesis, immunosuppression and tumor progression. To date, the vast majority of studies on macrophage phenotype and polarization have been based upon in vitro studies or murine model systems. We tested the hypothesis that distinct macrophage subsets can be identified within the microenvironment of lymphoid tumors and that the relative proportion of M1:M2 macrophages correlates with therapeutic response and/or resistance. In addition, we postulated that transcriptional analysis of distinct macrophage subpopulations would provide insights into mechanisms by which M2 macrophages promote tumor progression and reveal novel mechanisms which direct the interconversion of activated macrophages between classical and alternative activation states. Our focus has been on the evaluation of the tumor microenvironment in CNS lymphomas, the cerebrospinal fluid (CSF), which is enriched in inflammatory cells including activated CD14+ macrophages that we hypothesized would exhibit phenotypic features consistent with M1 and M2 polarization. Methods: We developed a novel 9-parameter flow-cytometric method to isolate distinct subpopulations of activated macrophages from CSF and peripheral blood. The method identifies macrophages with M1 features based upon expression of nitric oxide synthase (iNOS) and M2 macrophages on the basis of low-expression of iNOS and high expression of scavenger receptors CD206, CD209 and CD36. Subpopulations of macrophages were quantified and analyzed by FACS and transcriptional profiling (Affymetrix Gene Chip 1.0 ST). Serial analysis of CSF was performed in CNS lymphoma patients to correlate macrophage polarization states with response and/or progression. Parallel analyses were performed in blood in patients with non-Hodgkin lymphoma (NHL) to control conditions including infections and/or sarcoid. Results: At least four distinct subpopulations of activated macrophages were identified in CSF in association with CNS lymphoma (N=30) and controls (N=28). A greater than six-fold increase in the proportion of M2 macrophages was detected in CSF of CNS lymphoma patients compared to control subjects (p<0.001). By contrast, the proportion of CSF macrophages with M1 features was similar between NHL and controls. Moreover, peripheral blood macrophages from CNS lymphoma patients did not demonstrate significant M2-polarization. Serial analysis demonstrated that M2 polarization of CSF macrophages correlated with tumor progression and/or response. Transcriptional profiling analysis was conducted on macrophage subpopulations isolated from CSF of CNS lymphoma patients and controls. While few significant transcriptional differences were identified between M1 and unpolarized (Mnaive) macrophages, the transcriptional comparison of M2 vs. M1 as well as M2 vs. Mnaive macrophage subpopulations revealed several hundred differentially expressed genes with significant adjusted p-values. Pathway Analysis (Ingenuity) suggested mechanisms strongly associated with the M2 phenotype including activation of Notch signaling. Transcripts associated with short survival were most strongly expressed by M2 macrophages and included Ephrin A4 and lymphoid chemokines such as CXCL-13. The prognostic significance of high CXCL-13 and Ephrin A4 expression were confirmed by ELISA in an independent validation set of cases. Conclusions: We believe this to be the first application of flow-cytometry to define the phenotypes and dynamic interconversion of intratumoral macrophages within the lymphoma microenvironment and the first correlation of M2 macrophages with the evolution of resistance to therapy. In addition, this dataset provides the first in-depth transcriptional profiling analysis of in vivo human macrophage subpopulations and suggests novel mechanisms by which tumor-associated macrophages may facilitate lymphoma progression via the regulation of the metabolic microenvironment, angiogenesis, tumor invasion and immunosuppression. Based upon our additional preliminary data, we hypothesize that these results may be relevant to a variety of lymphoid tumors. Disclosures: Off Label Use: We will discuss the use of rituximab within the leptomeningeal compartment to treat recurrent/refractory CNS lymphomas.

871 In vitro immunoregulatory effect from cervical cancer derived mesenchymal stromal cells over molecules expression in monocyte derived macrophage polarization

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A923-A923
Author(s):  
Víctor Cortés-Morales ◽  
Juan Montesinos ◽  
Luis Chávez-Sánchez ◽  
Sandra Espíndola-Garibay ◽  
Alberto Monroy-García ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Stem Cells ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Macrophage Polarization ◽  
Induction Medium ◽  
M2 Macrophage ◽  
List Type ◽  
M2 Phenotype

BackgroundMacrophages are immunological cells that sense microenvironmental signals that may result in the polarized expression of either proinflammatory (M1) or anti-inflammatory (M2) phenotype.1 Macrophages M2 are present in tumoral microenvironment and their presence in patients with cervical cancer (CeCa) is related with less survival.2Mesenchymal Stromal Cells (MSCs) are also present in tumor microenvironment of cervical cancer (CeCa-MSC), which have shown immunoregulatory effects over CD8 T cells, decreasing their cytotoxic effect against tumoral cells.3 Interestingly, MSCs from bone marrow (BM-MSC) decrease M1 and increase M2 macrophage polarization in an in vitro coculture system.4 Macrophages and MSCs are present in microenvironment of cervical cancer, however it is unknown if MSCs play a role in macrophage polarization. In the present study, we have evaluated the immunoregulatory capacity of CeCa-MSCs to induce macrophage polarization.MethodsCD14 monocytes were isolated from peripheral blood and cultivated in the absence or presence of MSCs from BM, normal cervix (NCx) and CeCa. Two culture conditions were included, in the presence of induction medium to favors M1 (GM-CSF, LPS and IFNg) or M2 (M-CSF, IL-4 and IL-13) macrophage polarization. M1 (HLA-DR, CD80, CD86 and IFNg) or M2 (CD14, CD163, CD206, IDO and IL-10) macrophage molecular markers were evaluated by flow cytometry. Finally, we evaluated concentration of IL-10 and TNFa in conditioned medium form all coculture conditions.ResultsWe observed that CeCa-MSCs and BM-MSCs in presence of M1 induction medium, decreased M1 macrophage markers (HLA-II, CD80, CD86 and IFNg), and increase the expression of CD14 (M2 macrophage marker). Interestingly, in presence of M2 induction medium, BM-MSCs and CaCe-MSCs but not CxN-MSC increased CD163, CD206, IDO and IL-10 (M2 macrophage markers). We observed a decreased concentration of TNFa in the supernatant medium from all cocultures with MSCs, but only in presence of CeCa-MSCs, increased IL-10 concentration was detected in such cocultures.ConclusionsIn contrast to NCx-MSCs, CeCa-MSCs similarly to BM-MSCs have in vitro capacity to decrease M1 and increase M2 macrophage phenotype.AcknowledgementsAcknowledgments The authors are indebted to gratefully acknowledge to CONACYT (Grant No. 272793) and IMSS (Grant no. 1731) for support to Juan J. Montesinos research.ReferencesMartinez FO, Gordon S. The M1 and M2 paradigm of macrophage activation: time for reassessment. F1000Prime Rep 2014;6-13.Petrillo M, Zannoni GF, Martinelli E, et al. Polarization of tumor-associated macrophages toward M2 phenotype correlates with poor response to chemoradiation and reduced survival in patients with locally advanced cervical cancer. PLoS One 2015;10: e0136654.Montesinos JJ, Mora-García Mde L, et al. In vitro evidence of the presence of mesenchymal stromal cells in cervical cancer and their role in protecting cancer cells from cytotoxic T cell activity. Stem Cells Dev 2013;22:2508-2519.Vasandan AB, Jahnavi S, Shashank C. Human mesenchymal stem cells program macrophage plasticity by altering their metabolic status via a PGE 2-dependent mechanism. Sci Rep 2016;6:38308.

scholarly journals Macrophage Polarization in the Skin Lesion Caused by Neotropical Species of Leishmania sp

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Carmen M. Sandoval Pacheco ◽  
Gabriela V. Araujo Flores ◽  
Kadir Gonzalez ◽  
Claudia M. de Castro Gomes ◽  
Luiz F. D. Passero ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Macrophage Polarization ◽  
Leishmania Species ◽  
Skin Lesions ◽  
Host Cells ◽  
M2 Macrophage ◽  
M2 Macrophages ◽  
Intracellular Parasites ◽  
Skin Biopsies ◽  
Acquired Immune Responses

Macrophages play important roles in the innate and acquired immune responses against Leishmania parasites. Depending on the subset and activation status, macrophages may eliminate intracellular parasites; however, these host cells also can offer a safe environment for Leishmania replication. In this sense, the fate of the parasite may be influenced by the phenotype of the infected macrophage, linked to the subtype of classically activated (M1) or alternatively activated (M2) macrophages. In the present study, M1 and M2 macrophage subsets were analyzed by double-staining immunohistochemistry in skin biopsies from patients with American cutaneous leishmaniasis (ACL) caused by L. (L.) amazonensis, L. (V.) braziliensis, L. (V.) panamensis ,and L. (L.) infantum chagasi. High number of M1 macrophages was detected in nonulcerated cutaneous leishmaniasis (NUCL) caused by L. (L.) infantum chagasi ( M 1 = 112 ± 12 , M 2 = 43 ± 12 cells/mm2). On the other side, high density of M2 macrophages was observed in the skin lesions of patients with anergic diffuse cutaneous leishmaniasis (ADCL) ( M 1 = 195 ± 25 , M 2 = 616 ± 114 ), followed by cases of localized cutaneous leishmaniasis (LCL) caused by L. (L.) amazonensis ( M 1 = 97 ± 24 , M 2 = 219 ± 29 ), L. (V.) panamensis ( M 1 = 71 ± 14 , M 2 = 164 ± 14 ), and L. (V.) braziliensis ( M 1 = 50 ± 13 , M 2 = 53 ± 10 ); however, low density of M2 macrophages was observed in NUCL. The data presented herein show the polarization of macrophages in skin lesions caused by different Leishmania species that may be related with the outcome of the disease.

scholarly journals The effect of the WKYMVm peptide on promoting mBMSC secretion of exosomes to induce M2 macrophage polarization through the FPR2 pathway

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Wenbo Zhao ◽  
Junxian Hu ◽  
Qingyi He
Keyword(s):  
Western Blotting ◽  
Macrophage Polarization ◽  
Bone Defects ◽  
The Other ◽  
Formyl Peptide Receptor ◽  
Cell Counting ◽  
M2 Macrophage ◽  
M2 Macrophages ◽  
Lysosomal Activity ◽  
M2 Macrophage Polarization

Abstract Background When multicystic vesicles (precursors of exosomes) are formed in cells, there are two results. One is decomposition by lysosomes, and the other is the generation of exosomes that are transported out through the transmembrane. On the other hand, M2 macrophages promote the formation of local vascularization and provide necessary support for the repair of bone defects. To provide a new idea for the treatment of bone defects, the purpose of our study was to investigate the effect of WKYMVm (Trp-Lys-Tyr-Met-Val-D-Met-NH2) peptide on the secretion of exosomes from murine bone marrow-derived MSCs (mBMSCs) and the effect of exosomes on the polarization of M2 macrophages. Methods The WKYMVm peptide was used to activate the formyl peptide receptor 2 (FPR2) pathway in mBMSCs. First, we used Cell Counting Kit-8 (CCK-8) to detect the cytotoxic effect of WKYMVm peptide on mBMSCs. Second, we used western blotting (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) to detect the expression of interferon stimulated gene 15 (ISG15) and transcription factor EB (TFEB) in mBMSCs. Then, we detected lysosomal activity using a lysozyme activity assay kit. Third, we used an exosome extraction kit and western blotting to detect the content of exosomes secreted by mBMSCs. Fourth, we used immunofluorescence and western blotting to count the number of polarized M2 macrophages. Finally, we used an inhibitor to block miRNA-146 in exosomes secreted by mBMSCs and counted the number of polarized M2 macrophages. Results We first found that the WKYMVm peptide had no toxic effect on mBMSCs at a concentration of 1 μmol/L. Second, we found that when the FPR2 pathway was activated by the WKYMVm peptide in mBMSCs, ISG15 and TFEB expression was decreased, leading to increased secretion of exosomes. We also found that lysosomal activity was decreased when the FPR2 pathway was activated by the WKYMVm peptide in mBMSCs. Third, we demonstrated that exosomes secreted by mBMSCs promote the polarization of M2 macrophages. Moreover, all these effects can be blocked by the WRWWWW (WRW4, H-Trp-Arg-Trp-Trp-Trp-Trp-OH) peptide, an inhibitor of the FPR2 pathway. Finally, we confirmed the effect of miRNA-146 in exosomes secreted by mBMSCs on promoting the polarization of M2 macrophages. Conclusion Our findings demonstrated the potential value of the WKYMVm peptide in promoting the secretion of exosomes by mBMSCs and eventually leading to M2 macrophage polarization. We believe that our study could provide a research basis for the clinical treatment of bone defects.

scholarly journals ILC2 Proliferated by IL-33 Stimulation Alleviates Acute Colitis in Rag1-/- Mouse through Promoting M2 Macrophage Polarization

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yong You ◽  
Xiaoqing Zhang ◽  
Xiao Wang ◽  
Dan Yue ◽  
Fanxiang Meng ◽  
...  
Keyword(s):  
Body Weight ◽  
Macrophage Polarization ◽  
Epithelial Barrier ◽  
M2 Macrophage ◽  
Surface Markers ◽  
M2 Macrophages ◽  
Immunological Function ◽  
Innate Lymphoid Cell ◽  
Acute Colitis ◽  
M2 Macrophage Polarization

This study was to identify functions of ILC2, a newly found innate lymphoid cell which mainly locates in mucosa organs like lungs and intestines, in IBD. We injected rIL-33 protein to C57/BL6 mouse to explore how IL-33 induces ILC2 proliferation. The results showed that ILC2 reached a proliferation peak at day 5 and expressed multiple surface markers like CD127, C-kit, CD69, CD44, ST2, CD27, DR3, MHCII, and CD90.2. ILC2 also expressed high quantity of IL-13 and IL-5 and few IL-17A which indicates a potentially immunological function in IBD development. Afterwards, we transferred sort purified ILC2 to Rag1-/- mouse given DSS to induce acute colitis in order to explore the innate function of ILC2. Data showed that ILC2 alleviates DSS-induced acute innate colitis by repairing epithelial barrier and restore body weight. Furthermore, we found that ILC2 can cause macrophages polarizing to M2 macrophages in the gut. Therefore, we concluded that ILC2 played a therapeutic role in mouse acute colitis.

scholarly journals TMIC-51. GBP1 RECRUITS MACROPHAGES TO PROMOTE GLIOBLASTOMA GROWTH

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi259-vi259
Author(s):  
Lili Chen ◽  
Ming Li
Keyword(s):  
Macrophage Polarization ◽  
Tumor Development ◽  
M2 Macrophage ◽  
M2 Macrophages ◽  
Orthotopic Mouse Model ◽  
Ccl2 Expression ◽  
Molecule Inhibitor ◽  
Signaling Axis ◽  
And Migration

Abstract Guanylate binding protein 1 (GBP1) is an interferon-inducible large GTPase which plays a key role in tumor development, but the molecular mechanism is poorly understood. Here we investigated whether GBP1 could influence the tumor microenvironment in glioblastoma, the most common and malignant brain tumor. We found that forced expression of GBP1 in glioblastoma cells induced macrophage polarization toward an M2 phenotype via upregulating Chemokine (C-C motif) ligand 2 (CCL2). CCL2 acted via its receptor C-C chemokine receptor 2 (CCR2) to enhance macrophage cell migration in vitro. The M2 macrophages in turn promoted glioblastoma cell proliferation and migration. The orthotopic mouse model showed that GBP1 recruited M2 macrophages into tumor to promote glioblastoma progression, and targeting CCL2/CCR2 signaling axis with a small molecule inhibitor RS504393 led to decreased macrophage attraction and M2 polarization and a significant tumor growth retardation and prolonged survival of tumor-bearing mice. Clinically, GBP1 expression positively correlated with M2 macrophage numbers and CCL2 expression in glioblastoma. Taken together, our results reveal that GBP1 modulates the tumor immune microenvironment through CCL2 induction to promote glioblastoma infiltrating growth, and targeting tumor-associated macrophages may represent a new therapeutic strategy against glioblastoma.

scholarly journals Crosstalk between adipocytes and M2 macrophages compensates for osteopenic phenotype in the Lrp5-deficient mice

2020 ◽  
pp. 153537022097232
Author(s):  
Lisha Li ◽  
Xuemin Qiu ◽  
Na Zhang ◽  
Yan Sun ◽  
Yan Wang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Wnt Signaling ◽  
Macrophage Polarization ◽  
Myeloid Cells ◽  
Osteogenic Potential ◽  
Enzyme Linked Immunosorbent Assay ◽  
Tartrate Resistant Acid Phosphatase ◽  
M2 Macrophage ◽  
M2 Macrophages ◽  
Alizarin Red

A loss-of-function mutation in the Lrp5 gene in mice leads to a low bone mass disorder due to the inhibition of the canonical Wnt signaling pathway; however, the role of bone marrow microenvironment in mice with this mutation remains unclear. In this study, we evaluated proliferation and osteogenic potential of mouse osteoblasts using the MTT assay and Alizarin red staining. The levels of alkaline phosphatase, tartrate-resistant acid phosphatase, and adiponectin in culture supernatants were measured using the enzyme-linked immunosorbent assay. Osteoclast bone resorbing activity was evaluated by toluidine staining and the number and area of bone resorption pits were determined. We observed increased osteogenesis in osteoblasts co-cultured with the BM-derived myeloid cells compared to the osteoblasts cultured alone. Mice with global Lrp5 deletion had a relatively higher bone density compared to the mice carrying osteoblast/osteocyte-specific Lrp5 deletion. An increased frequency of M2 macrophages and reduced expression of inflammatory cytokines were detected in the myeloid cells derived from the bone marrow of mice with global Lrp5 deletion. Higher adipogenic potential and elevated levels of adiponectin in the global Lrp5 deletion mice contributed to the preferential M2 macrophage polarization. Here, we identified a novel systemic regulatory mechanism of bone formation and degradation in mice with global Lrp5 deletion. This mechanism depends on a crosstalk between the adipocytes and M2 macrophages in the bone marrow and is responsible for partly rescuing osteopenia developed as a result of decreased Wnt signaling.

scholarly journals Mitochondrial Calcium Uptake Is Instrumental to Alternative Macrophage Polarization and Phagocytic Activity

2019 ◽  
Vol 20 (19) ◽  
pp. 4966 ◽  
Author(s):  
Tedesco ◽  
Scattolini ◽  
Albiero ◽  
Bortolozzi ◽  
Avogaro ◽  
...  
Keyword(s):  
Phagocytic Activity ◽  
Calcium Uptake ◽  
Macrophage Polarization ◽  
Mitochondrial Calcium ◽  
M2 Macrophage ◽  
M2 Macrophages ◽  
Mitochondrial Calcium Uniporter ◽  
E Coli ◽  
Calcium Uniporter ◽  
Mitochondrial Calcium Uptake

Macrophages are highly plastic and dynamic cells that exert much of their function through phagocytosis. Phagocytosis depends on a coordinated, finely tuned, and compartmentalized regulation of calcium concentrations. We examined the role of mitochondrial calcium uptake and mitochondrial calcium uniporter (MCU) in macrophage polarization and function. In primary cultures of human monocyte-derived macrophages, calcium uptake in mitochondria was instrumental for alternative (M2) macrophage polarization. Mitochondrial calcium uniporter inhibition with KB-R7943 or MCU knockdown, which prevented mitochondrial calcium uptake, reduced M2 polarization, while not affecting classical (M1) polarization. Challenging macrophages with E. coli fragments induced spikes of mitochondrial calcium concentrations, which were prevented by MCU inhibition or silencing. In addition, mitochondria remodelled in M2 macrophages during phagocytosis, especially close to sites of E. coli internalization. Remarkably, inhibition or knockdown of MCU significantly reduced the phagocytic capacity of M2 macrophages. KB-R7943, which also inhibits the membrane sodium/calcium exchanger and Complex I, reduced mitochondria energization and cellular ATP levels, but such effects were not observed with MCU silencing. Therefore, phagocytosis inhibition by MCU knockdown depended on the impaired mitochondrial calcium buffering rather than changes in mitochondrial and cellular energy status. These data uncover a new role for MCU in alternative macrophage polarization and phagocytic activity.

scholarly journals Tumor-derived exosomal miR-934 induces macrophage M2 polarization to promote liver metastasis of colorectal cancer

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Senlin Zhao ◽  
Yushuai Mi ◽  
Bingjie Guan ◽  
Binbin Zheng ◽  
Ping Wei ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Liver Metastasis ◽  
Molecular Mechanisms ◽  
Macrophage Polarization ◽  
In Vitro Assays ◽  
Luciferase Reporter ◽  
M2 Macrophage ◽  
M2 Macrophages ◽  
Premetastatic Niche ◽  
Niche Formation

Abstract Background Mounting evidence has demonstrated the vital importance of tumor-associated macrophages (TAMs) and exosomes in the formation of the premetastatic niche. However, the molecular mechanisms by which tumor-derived exosomal miRNAs interact with TAMs underlying premetastatic niche formation and colorectal cancer liver metastasis (CRLM) remain largely unknown. Methods Transmission electron microscopy and differential ultracentrifugation were used to verify the existence of exosomes. In vivo and in vitro assays were used to identify roles of exosomal miR-934. RNA pull-down assay, dual-luciferase reporter assay, etc. were applied to clarify the mechanism of exosomal miR-934 regulated the crosstalk between CRC cells and M2 macrophages. Results In the present study, we first demonstrated the aberrant overexpression of miR-934 in colorectal cancer (CRC), especially in CRLM, and its correlation with the poor prognosis of CRC patients. Then, we verified that CRC cell-derived exosomal miR-934 induced M2 macrophage polarization by downregulating PTEN expression and activating the PI3K/AKT signaling pathway. Moreover, we revealed that hnRNPA2B1 mediated miR-934 packaging into exosomes of CRC cells and then transferred exosomal miR-934 into macrophages. Interestingly, polarized M2 macrophages could induce premetastatic niche formation and promote CRLM by secreting CXCL13, which activated a CXCL13/CXCR5/NFκB/p65/miR-934 positive feedback loop in CRC cells. Conclusions These findings indicate that tumor-derived exosomal miR-934 can promote CRLM by regulating the crosstalk between CRC cells and TAMs. These findings reveal a tumor and TAM interaction in the metastatic microenvironment mediated by tumor-derived exosomes that affects CRLM. The present study also provides a theoretical basis for secondary liver cancer.

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