scholarly journals Decidual glycodelin-A polarizes human monocytes into a decidual macrophage-like phenotype through Siglec-7

2020 ◽  
Vol 133 (14) ◽  
pp. jcs244400 ◽  
Author(s):  
Madhavi Vijayan ◽  
Cheuk-Lun Lee ◽  
Vera H. H. Wong ◽  
Xia Wang ◽  
Kungfeng Bai ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Immune Cell ◽  
Fetal Loss ◽  
Cell Types ◽  
Dependent Manner ◽  
Human Monocytes ◽  
Placental Development ◽  
Cell Functions ◽  
Surface Marker Expression ◽  
Glycodelin A

ABSTRACTDecidual macrophages constitute 20–30% of the total leukocytes in the uterus of pregnant women, regulating the maternal immune tolerance and placenta development. Abnormal number or activities of decidual macrophages (dMs) are associated with fetal loss and pregnancy complications, such as preeclampsia. Monocytes differentiate into dMs in a decidua-specific microenvironment. Despite their important roles in pregnancy, the exact factors that regulate the differentiation into dMs remain unclear. Glycodelin-A (PAEP, hereafter referred to as GdA) is a glycoprotein that is abundantly present in the decidua, and plays an important role in fetomaternal defense and placental development. It modulates the differentiation and activity of several immune cell types residing in the decidua. In this study, we demonstrated that GdA induces the differentiation of human monocytes into dM-like phenotypes in terms of transcriptome, cell surface marker expression, secretome, and regulation of trophoblast and endothelial cell functions. We found that Sialic acid-binding Ig-like lectin 7 (Siglec-7) mediates the binding and biological actions of GdA in a sialic acid-dependent manner. We, therefore, suggest that GdA, induces the polarization of monocytes into dMs to regulate fetomaternal tolerance and placental development.

scholarly journals Probing the binding specificities of human Siglecs by cell-based glycan arrays

2021 ◽  
Vol 118 (17) ◽  
pp. e2026102118
Author(s):  
Christian Büll ◽  
Rebecca Nason ◽  
Lingbo Sun ◽  
Julie Van Coillie ◽  
Daniel Madriz Sørensen ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Cell Surface ◽  
Immune Cell ◽  
Late Onset ◽  
Cell Types ◽  
Hek293 Cells ◽  
Cell Functions ◽  
Binding Epitope ◽  
Sialic Acid Binding ◽  
Complex Glycan

Siglecs are a family of sialic acid–binding receptors expressed by cells of the immune system and a few other cell types capable of modulating immune cell functions upon recognition of sialoglycan ligands. While human Siglecs primarily bind to sialic acid residues on diverse types of glycoproteins and glycolipids that constitute the sialome, their fine binding specificities for elaborated complex glycan structures and the contribution of the glycoconjugate and protein context for recognition of sialoglycans at the cell surface are not fully elucidated. Here, we generated a library of isogenic human HEK293 cells with combinatorial loss/gain of individual sialyltransferase genes and the introduction of sulfotransferases for display of the human sialome and to dissect Siglec interactions in the natural context of glycoconjugates at the cell surface. We found that Siglec-4/7/15 all have distinct binding preferences for sialylated GalNAc-type O-glycans but exhibit selectivity for patterns of O-glycans as presented on distinct protein sequences. We discovered that the sulfotransferase CHST1 drives sialoglycan binding of Siglec-3/8/7/15 and that sulfation can impact the preferences for binding to O-glycan patterns. In particular, the branched Neu5Acα2–3(6-O-sulfo)Galβ1–4GlcNAc (6′-Su-SLacNAc) epitope was discovered as the binding epitope for Siglec-3 (CD33) implicated in late-onset Alzheimer’s disease. The cell-based display of the human sialome provides a versatile discovery platform that enables dissection of the genetic and biosynthetic basis for the Siglec glycan interactome and other sialic acid–binding proteins.

scholarly journals Glucose Triggers ATP Secretion from Bacteria in a Growth-Phase-Dependent Manner

2013 ◽  
Vol 79 (7) ◽  
pp. 2328-2335 ◽  
Author(s):  
Ippei Hironaka ◽  
Tadayuki Iwase ◽  
Shinya Sugimoto ◽  
Ken-ichi Okuda ◽  
Akiko Tajima ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Growth Phase ◽  
Cell Function ◽  
Immune Cell ◽  
Dependent Manner ◽  
T Helper 17 ◽  
Content Type ◽  
Cell Functions ◽  
Atp Secretion ◽  
Enterococcus Gallinarum

ABSTRACTATP modulates immune cell functions, and ATP derived from gut commensal bacteria promotes the differentiation of T helper 17 (Th17) cells in the intestinal lamina propria. We recently reported thatEnterococcus gallinarum, isolated from mice and humans, secretes ATP. We have since found and characterized several ATP-secreting bacteria. Of the tested enterococci,Enterococcus mundtiisecreted the greatest amount of ATP (>2 μM/108cells) after overnight culture. Glucose, not amino acids and vitamins, was essential for ATP secretion fromE. mundtii. Analyses of energy-deprived cells demonstrated that glycolysis is the most important pathway for bacterial ATP secretion. Furthermore, exponential-phaseE. mundtiiandEnterococcus faecaliscells secrete ATP more efficiently than stationary-phase cells. Other bacteria, includingPseudomonas aeruginosa,Escherichia coli, andStaphylococcus aureus, also secrete ATP in exponential but not stationary phase. These results suggest that various gut bacteria, including commensals and pathogens, might secrete ATP at any growth phase and modulate immune cell function.

Surfactant protein D decreases pollen-induced IgE-dependent mast cell degranulation

2005 ◽  
Vol 289 (5) ◽  
pp. L856-L866 ◽  
Author(s):  
Delphine C. Malherbe ◽  
Veit J. Erpenbeck ◽  
Soman N. Abraham ◽  
Erika C. Crouch ◽  
Jens M. Hohlfeld ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Immune Cell ◽  
Allergic Inflammation ◽  
Surfactant Protein ◽  
Mast Cell Degranulation ◽  
Surfactant Protein D ◽  
Dependent Manner ◽  
Cell Functions ◽  
Pulmonary Surfactant Proteins

Mast cells play a key role in allergy and asthma. They reside at the host-environment interface and are among the first cells to make contact with inhaled microorganisms and particulate antigens. Pulmonary surfactant proteins A and D (SP-A and SP-D) function in lung host defense by enhancing microbe phagocytosis and mediating other immune cell functions, but little is known about their effects on mast cells. We hypothesized that SP-A and/or SP-D modulate IgE-dependent mast cell functions. Pollen starch granules (PSG) extracted from Dactylis glomerata and coated with trinitrophenol (TNP) were used as a model of an inhaled organic particulate allergen. Our data revealed that SP-D inhibited by 50% the release of β-hexosaminidase by peritoneal mast cells sensitized with IgE anti-TNP and stimulated with TNP-PSG. In contrast, SP-A had no effect. Furthermore, SP-D aggregated PSG in a dose-dependent manner, and this aggregation was mediated by SP-D's carbohydrate recognition domain. A single arm SP-D mutant (RrSP-Dser15,20) neither aggregated PSG nor inhibited degranulation, suggesting that multimerization of SP-D is required for maximal PSG aggregation and inhibition of PSG-induced mast cell degranulation. This study is the first to demonstrate that SP-D modulates IgE-mediated mast cell functions, which are important in asthma and allergic inflammation.

scholarly journals Differential Modulation of 25-hydroxycholecalciferol on Innate Immunity of Broiler Breeder Hens

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1742
Author(s):  
Pao-Chia Chou ◽  
Pei-Chi Lin ◽  
Shu-Wei Wu ◽  
Chien-Kai Wang ◽  
Thau-Kiong Chung ◽  
...  
Keyword(s):  
Feed Intake ◽  
Respiratory Burst ◽  
Immune Cell ◽  
Growth Period ◽  
Dependent Manner ◽  
Immune Functions ◽  
Bacterial Killing ◽  
Cell Functions ◽  
Breeder Hens ◽  
25 Hydroxycholecalciferol

Past immunological studies in broilers focused on juveniles within the rapid pre-slaughter growth period and may not reflect adult immune responses, particularly in breeders managed with chronic feed restriction (R). The study aimed to assess innate immune cell functions in respect to R vs. ad libitum (Ad) feed intake in breeder hens with and without dietary 25-hydroxycholecalciferol (25-OH-D3) supplementation. Ad-feed intake consistently suppressed IL-1β secretion, respiratory burst, and cell livability in peripheral heterophils and/or monocytes along the feeding trial from the age of 51 to 68 weeks. Supplemental 25-OH-D3 repressed IL-1β secretion and respiratory burst of both cells mostly in R-hens, but promoted monocyte phagocytosis, chemotaxis, and bacterial killing activity in Ad-hens in accompany with relieved hyperglycemia, hyperlipidemia, and systemic inflammation. Overnight cultures with leukocytes from R-hens confirmed the differential effects of 25-OH-D3 to rescue immune functions altered by glucose and/or palmitic acid exposure. Studies with specific inhibitors further manifested the operative mechanisms via glucolipotoxicity in a cell type- and function-dependent manner. The results concluded no predominant changes between R- vs. Ad-feed intake on leukocyte defense against pathogens despite some differential differences, but supplemental 25-OH-D3 exerts more pronounced effects in Ad-hens.

scholarly journals Hypoxia modulates human mast cell adhesion to hyaluronic acid

2021 ◽  
Author(s):  
Joanna Pastwińska ◽  
Aurelia Walczak-Drzewiecka ◽  
Elżbieta Kozłowska ◽  
Enjuro Harunari ◽  
Marcin Ratajewski ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Mast Cell ◽  
Hyaluronic Acid ◽  
Cell Adhesion ◽  
Mast Cells ◽  
Immune Cell ◽  
Human Mast Cell ◽  
Dependent Manner ◽  
Cell Functions ◽  
Extracellular Matrix Components

AbstractHypoxia is an inherent factor in the inflammatory process and is important in the regulation of some immune cell functions, including the expression of mast cell pro- and anti-inflammatory mediators. Hypoxia also influences cell adhesion to the extracellular matrix (ECM). Hyaluronic acid is one of the major components of the ECM that is involved in inflammatory and tissue regeneration processes in which mast cells play a prominent role. This prompted us to investigate the effects of hypoxia on the expression of hyaluronic acid receptors in mast cells and mast cell adhesion to this ECM component. We found that human LAD2 mast cells spontaneously adhered to hyaluronic acid in a CD44-dependent manner and that reduced oxygen concentrations inhibited or even completely abolished this adhesion process. The mechanism of hypoxia downregulation of mast cell adhesion to hyaluronic acid did not involve a decrease in CD44 expression and hyaluronidase-mediated degradation of adhesion substrates but rather conformational changes in the avidity of CD44 to hyaluronic acid. Hypoxia-mediated regulation of mast cell adhesion to extracellular matrix components might be involved in the pathogenic accumulation of mast cells observed in the course of certain diseases including rheumatoid arthritis and cancer.

scholarly journals OTME-6. Deep sequencing reveals heterogeneity of brain metastasis-associated macrophages and microglia and uncovers their cell type-specific functions within the tumor microenvironment

2021 ◽  
Vol 3 (Supplement_2) ◽  
pp. ii14-ii14
Author(s):  
Michael Schulz ◽  
Tijna Alekseeva ◽  
Julian Anthes ◽  
Jandranka Macas ◽  
Birgitta Michels ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Immune Cell ◽  
Inflammatory Responses ◽  
Whole Brain Radiotherapy ◽  
Cell Types ◽  
Therapy Resistance ◽  
Cell Type ◽  
Cell Functions ◽  
Brain Radiotherapy ◽  
Cell Type Specific

Abstract Macrophages represent a highly plastic cell type,indispensable for tissue and organ homeostasis, as well as innate immunity. Basic and translational research attributed tumor-promoting functions to macrophages, and their presence is often associated to poor patient prognosis and therapy resistance. While brain-resident macrophages, the so-called microglia (MG), represent the major immune cell type in the parenchyma under normal conditions, primary and metastatic brain tumors induce the recruitment of different immune cell types from the periphery, including monocyte-derived macrophages (MDM). Controversy remained about the redundancy of disease-associated molecular signatures and functions. The identification of markers that reliably distinguish brain-resident from blood-borne tumor-associated macrophages (TAMs) allowed the interrogation of molecular traits of different TAM populations in mouse and human brain tumors. Using RNA-Seq, we demonstrated that TAMs rapidly acquire disease-associated transcriptional programs upon initial tumor infiltration, while gene expression remained stable during different stages of BrM progression. Across different BrM models, disease-associated transcriptional changes revealed lineage-specific, non-redundant functions of TAM populations, which was further reflected by cell type-specific occupation of different niches within the BrM microenvironment. Furthermore, we observed dose- and cell type-specific immune modulatory effects of whole brain radiotherapy on myeloid cells in BrM leading to a transient loss of disease-associated transcriptional programs predominately in blood-borne myeloid populations. This effect can at least in part be attributed to a replenishment of the recruited macrophage pool. This observation was further supported by scRNA-Seq analyses revealing higher heterogeneity of TAM-MDM compared to TAM-MG under treatment-naïve conditions and in response to radiotherapy. Together, our results point towards the phenotypic plasticity of TAMs, especially MDMs, and the contribution of each compartment in instigating cancer-associated inflammation or the establishment of an immuno-suppressive TME. While TAM-MG exert functions related to pro-inflammatory responses, TAM-MDM are rather involved in tissue repair and regulation of adaptive immune cell functions.

scholarly journals Hypersialylation in Cancer: Modulation of Inflammation and Therapeutic Opportunities

Cancers ◽  
2018 ◽  
Vol 10 (6) ◽  
pp. 207 ◽  
Author(s):  
Emily Rodrigues ◽  
Matthew Macauley
Keyword(s):  
Sialic Acid ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Immune Cell ◽  
Cell Types ◽  
Functional Roles ◽  
Cell Responses ◽  
Disease Prognosis ◽  
Sialic Acid Binding ◽  
Cancer Types

Cell surface glycosylation is dynamic and often changes in response to cellular differentiation under physiological or pathophysiological conditions. Altered glycosylation on cancers cells is gaining attention due its wide-spread occurrence across a variety of cancer types and recent studies that have documented functional roles for aberrant glycosylation in driving cancer progression at various stages. One change in glycosylation that can correlate with cancer stage and disease prognosis is hypersialylation. Increased levels of sialic acid are pervasive in cancer and a growing body of evidence demonstrates how hypersialylation is advantageous to cancer cells, particularly from the perspective of modulating immune cell responses. Sialic acid-binding receptors, such as Siglecs and Selectins, are well-positioned to be exploited by cancer hypersialylation. Evidence is also mounting that Siglecs modulate key immune cell types in the tumor microenvironment, particularly those responsible for maintaining the appropriate inflammatory environment. From these studies have come new and innovative ways to block the effects of hypersialylation by directly reducing sialic acid on cancer cells or blocking interactions between sialic acid and Siglecs or Selectins. Here we review recent works examining how cancer cells become hypersialylated, how hypersialylation benefits cancer cells and tumors, and proposed therapies to abrogate hypersialylation of cancer.

scholarly journals Targeting the “PVR–TIGIT axis” with immune checkpoint therapies

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 354 ◽  
Author(s):  
Laurent Gorvel ◽  
Daniel Olive
Keyword(s):  
Immune Checkpoint ◽  
Cell Activation ◽  
Immune Cell ◽  
Checkpoint Inhibitors ◽  
Cell Types ◽  
Lymphoid Cells ◽  
Effector Cells ◽  
Cell Functions ◽  
Target Molecules ◽  
Different Cell Types

Checkpoint inhibitors have become an efficient way to treat cancers. Indeed, anti-CTLA-4, anti-PD1, and anti-PDL-1 antibodies are now used as therapies for cancers. However, while these therapies are very efficient in certain tumors, they remain poorly efficient in others. This might be explained by the immune infiltrate, the expression of target molecules, and the influence of the tumor microenvironment. It is therefore critical to identify checkpoint antigens that represent alternative targets for immunotherapies. PVR-like molecules play regulatory roles in immune cell functions. These proteins are expressed by different cell types and have been shown to be upregulated in various malignancies. PVR and Nectin-2 are expressed by tumor cells as well as myeloid cells, while TIGIT, CD96, and DNAM-1 are expressed on effector lymphoid cells. PVR is able to bind DNAM-1, CD96, and TIGIT, which results in two distinct profiles of effector cell activation. Indeed, while binding to DNAM-1 induces the release of cytokines and cytotoxicity of cytotoxic effector cells, binding TIGIT induces an immunosuppressive and non-cytotoxic profile. PVR is also able to bind CD96, which induces an immunosuppressive response in murine models. Unfortunately, in humans, results remain contradictory, and this interaction might induce the activation or the suppression of the immune response. Similarly, Nectin-2 was shown to bind TIGIT and to induce regulatory profiles in effectors cells such as NK and T cells. Therefore, these data highlight the potential of each of the molecules of the “PVR–TIGIT axis” as a potential target for immune checkpoint therapy. However, many questions remain to be answered to fully understand the mechanisms of this synapse, in particular for human CD96 and Nectin-2, which are still understudied. Here, we review the recent advances in “PVR–TIGIT axis” research and discuss the potential of targeting this axis by checkpoint immunotherapies.

scholarly journals Disruption of Glucocorticoid Action on CD11c+ Dendritic Cells Favors the Generation of CD4+ Regulatory T Cells and Improves Fetal Development in Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Lianghui Diao ◽  
Alexandra Maximiliane Hierweger ◽  
Agnes Wieczorek ◽  
Petra Clara Arck ◽  
Kristin Thiele
Keyword(s):  
Dendritic Cells ◽  
Fetal Development ◽  
Immune Cell ◽  
Fetal Loss ◽  
Treg Cells ◽  
Cell Functions ◽  
Adaptive Immune Cells ◽  
Uterine Growth ◽  
Intra Uterine Growth Restriction ◽  
Functional Relevance

A wealth of innate and adaptive immune cells and hormones are involved in mounting tolerance towards the fetus, a key aspect of successful reproduction. We could recently show that the specific cross talk between the pregnancy hormone progesterone and dendritic cells (DCs) is significantly engaged in the generation of CD4+ FoxP3+ regulatory T (Treg) cells while a disruption led to placental alterations and intra-uterine growth restriction. Apart from progesterone, also glucocorticoids affect immune cell functions. However, their functional relevance in the context of pregnancy still needs clarification. We developed a mouse line with a selective knockout of the glucocorticoid receptor (GR) on DCs, utilizing the cre/flox system. Reproductive outcome and maternal immune and endocrine adaptation of Balb/c-mated C57Bl/6 GRflox/floxCD11ccre/wt (mutant) females was assessed on gestation days (gd) 13.5 and 18.5. Balb/c-mated C57Bl/6 GRwt/wtCD11ccre/wt (wt) females served as controls. The number of implantation and fetal loss rate did not differ between groups. However, we identified a significant increase in fetal weight in fetuses from mutant dams. While the frequencies of CD11c+ cells remained largely similar, a decreased expression of co-stimulatory molecules was observed on DCs of mutant females on gd 13.5, along with higher frequencies of CD4+ and CD8+ Treg cells. Histomorphological and gene expression analysis revealed an increased placental volume and an improved functional placental capacity in mice lacking the GR on CD11c+ DCs. In summary, we here demonstrate that the disrupted communication between GCs and DCs favors a tolerant immune microenvironment and improves placental function and fetal development.

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