Project description:The role of placental macrophages is largely ignored in the success of pregnancy. We found that CD14+ macrophages purified from at-term placentas spontaneously matured into multinucleated giant cells (MGCs). MGCs lost the expression of CD14 and co-inhibitory molecules, such as Programmed cell Death-Ligands 1 and 2. Although MGCs kept phagocytosis and property to produce ROS, their inflammatory potential measured by TNF/IL-10 imbalance and activation of p38 MAPK and NF-M-NM-:B was blunted without being associated with M2 phenotype. The investigation of gene expression revealed the enrichment with categories related to inflammation, apoptosis and canonical functions of macrophages in MGCs. Whereas most of the genes associated with inflammation and immune responses were down-modulated, those such as VEGFC or associated with matrix remodeling were specifically up-regulated in MGCs. Importantly, we found that patients with preeclampsia or chorioamnionitis, two inflammatory and infectious pathologies, respectively, that affect placentas, were unable to generate MGCs. Taken together, these results suggest that MGCs represent a new way to regulate the inflammatory and cytocidal activity of placental macrophages in a context that imposes contradictory constraints, such as semi-allograft acceptance and defense against aggression. The dysregulation of MGC formation may be associated with placental inflammatory and infectious pathologies. Placental macrophages CD14+ were cultured for 9 days to form multinucleated giant cells (MGC). The transcriptome of MGCs was compared to the transcriptome of placental macrophages (CD14+)
Project description:Monocytes/macrophages have the ability to fuse in multinucleated giant cells (MGCs). Except for osteoclasts that resorb bones on large surfaces, the function of other macrophage-derived MGCs, which appear under pathological situations associated with granulomatous inflammation such as tuberculosis, is not understood. Here we deciphered functions and gene expression profiles of MGCs obtained after stimulation of human monocytes with IFN-gM-BM- and concanavalin A. First, we show that the competence of MGCs in phagocytosis and O2- production was similar to those of monocytes-derived macrophages (MDMs) and that MGCs exhibited a M1 polarization. Second, we analyzed the transcriptional profile of MGCs using gene categories and the building of gene networks. The signature of MGCs was markedly distinct from that of resting or stimulated MDMs. It consisted of the up-regulation of genes involved in adhesion and cytoskeleton organization while genes associated with immune response were down-regulated. Hence, MGC formation was associated with a profound and original modulation of gene expression repertoire suggesting that macrophage immune were not prominent in MGC. This expression gene repertoire may be instrumental to understand the specific function of this giant macrophages in human pathologies 9 samples of monocytes-derived macrophages and 3 samples of mulitnucleated giant cells. 3 samples of MDM treated with concanavalin A, 3 samples of MDM treated with IFN-g, and 3 control MDM.
Project description:Cardiac involvement is an important determinant of mortality amongst sarcoidosis patients. While granulomatous inflammation is a hallmark finding in cardiac sarcoidosis, the precise immune cell populations that comprise the granuloma remain unresolved. Furthermore, it is unclear how the cellular and transcriptomic landscape of cardiac sarcoidosis differs from other inflammatory heart diseases. We leveraged spatial transcriptomics (GeoMx DSP) and single nucleus RNA sequencing (snRNAseq) to elucidate the cellular and transcriptional landscape of cardiac sarcoidosis. Using GeoMX DSP technology, we compared the transcriptomal profile of CD68+ rich immune cell infiltrates in human cardiac sarcoidosis, giant cell myocarditis, and lymphocytic myocarditis. We performed snRNAseq of human cardiac sarcoidosis to identify immune cell types and examined their transcriptomic landscape and regulation. Using multi-channel immunofluorescence staining, we validated immune cell populations identified by snRNAseq, determined their spatial relationship, and devised an immunostaining approach to distinguish cardiac sarcoidosis from other inflammatory heart diseases. Despite overlapping histological features, spatial transcriptomics identified transcriptional signatures and associated pathways that robustly differentiated cardiac sarcoidosis from giant cell myocarditis and lymphocytic myocarditis. snRNAseq revealed the presence of diverse populations of myeloid cells in cardiac sarcoidosis with distinct molecular features. We identified GPNMB as a novel marker of multinucleated giant cells and predicted that the MITF family of transcription factors regulated this cell type. We also detected additional macrophage populations in cardiac sarcoidosis including HLA-DR+ macrophages, SYTL3+ macrophages and CD163+ resident macrophages. HLA-DR+ macrophages were found immediately adjacent to GPMMB+ giant cells, a distinct feature compared with other inflammatory cardiac diseases. SYTL3+ macrophages were located scattered throughout the granuloma and CD163+ macrophages, CD1c+ dendritic cells, non-classical monocytes, and T-cells were located at the periphery and outside of the granuloma. Finally, we demonstrate mTOR pathway activation is associated with proliferation and is selectively found in HLA-DR+ and SYLT3+ macrophages. In this study, we identified diverse populations of immune cells with distinct molecular signatures that comprise the sarcoid granuloma. These findings provide new insights into the pathology of cardiac sarcoidosis and highlight opportunities to improve diagnostic testing.
Project description:To investigate the effects of macrophage cell fusion and multinucleation, we have sorted mononuclear and multinucleated macrophages from 3 types of polykaryons: osteoclasts, foreign body giant cells (FBGCs) and Langhans giant cells (LGCs).
Project description:Bone marrow-derived macrophages can form multinucleated giant cells upon FSL-1 stimulation in vitro, which can be prevented by supplementation with nutlin-3a
Project description:Macrophage multinucleation (MM) is essential for various biological processes such as osteoclast-mediated bone resorption and multinucleated giant cell-associated inflammatory reactions. Here we study the molecular pathways underlying multinucleation in the rat through an integrative approach combining MS-based quantitative phosphoproteomics and transcriptome (high throughput RNA-sequencing) to identify new regulators of MM. We show that a strong metabolic shift towards HIF1-mediated glycolysis occurs at transcriptomic level during MM, together with modifications in phosphorylation of over 50 proteins including several ARF GTPase activators and polyphosphate inositol phosphatases. These results will provide a new framework for the combined analysis of transcriptional and post-translational changes during macrophage multinucleation, prioritizing essential genes and revealing the sequential events leading to the multinucleation of macrophages.
Project description:Monocytes/macrophages have the ability to fuse in multinucleated giant cells (MGCs). Except for osteoclasts that resorb bones on large surfaces, the function of other macrophage-derived MGCs, which appear under pathological situations associated with granulomatous inflammation such as tuberculosis, is not understood. Here we deciphered functions and gene expression profiles of MGCs obtained after stimulation of human monocytes with IFN-g and concanavalin A. First, we show that the competence of MGCs in phagocytosis and O2- production was similar to those of monocytes-derived macrophages (MDMs) and that MGCs exhibited a M1 polarization. Second, we analyzed the transcriptional profile of MGCs using gene categories and the building of gene networks. The signature of MGCs was markedly distinct from that of resting or stimulated MDMs. It consisted of the up-regulation of genes involved in adhesion and cytoskeleton organization while genes associated with immune response were down-regulated. Hence, MGC formation was associated with a profound and original modulation of gene expression repertoire suggesting that macrophage immune were not prominent in MGC. This expression gene repertoire may be instrumental to understand the specific function of this giant macrophages in human pathologies
Project description:The role of placental macrophages is largely ignored in the success of pregnancy. We found that CD14+ macrophages purified from at-term placentas spontaneously matured into multinucleated giant cells (MGCs). MGCs lost the expression of CD14 and co-inhibitory molecules, such as Programmed cell Death-Ligands 1 and 2. Although MGCs kept phagocytosis and property to produce ROS, their inflammatory potential measured by TNF/IL-10 imbalance and activation of p38 MAPK and NF-κB was blunted without being associated with M2 phenotype. The investigation of gene expression revealed the enrichment with categories related to inflammation, apoptosis and canonical functions of macrophages in MGCs. Whereas most of the genes associated with inflammation and immune responses were down-modulated, those such as VEGFC or associated with matrix remodeling were specifically up-regulated in MGCs. Importantly, we found that patients with preeclampsia or chorioamnionitis, two inflammatory and infectious pathologies, respectively, that affect placentas, were unable to generate MGCs. Taken together, these results suggest that MGCs represent a new way to regulate the inflammatory and cytocidal activity of placental macrophages in a context that imposes contradictory constraints, such as semi-allograft acceptance and defense against aggression. The dysregulation of MGC formation may be associated with placental inflammatory and infectious pathologies.