Defective fetal liver erythropoiesis and T lymphopoiesis in mice lacking the phosphatidylserine receptor

Blood ◽  
2004 ◽  
Vol 103 (9) ◽  
pp. 3362-3364 ◽  
Author(s):  
Yuya Kunisaki ◽  
Sadahiko Masuko ◽  
Mayuko Noda ◽  
Ayumi Inayoshi ◽  
Terukazu Sanui ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Apoptotic Cell ◽  
Fetal Liver ◽  
Lymphoid Cells ◽  
Cell Uptake ◽  
Developmental Defect ◽  
Apoptotic Cells ◽  
Phosphatidylserine Receptor ◽  
T Lymphopoiesis

Abstract Clearance of apoptotic cells by macrophages is considered important for prevention of inflammatory responses leading to tissue damage. The phosphatidylserine receptor (PSR), which specifically binds to phosphatidylserine (PS) exposed on the surface of apoptotic cells, mediates uptake of apoptotic cells in vitro, yet the physiologic relevance of PSR remains unknown. This issue was addressed by generating PSR-deficient (PSR-/-) mice. PSR-/- mice exhibited severe anemia and died during the perinatal period. In the PSR-/- fetal livers, erythroid differentiation was blocked at an early erythroblast stage. In addition, PSR-/- embryos exhibited thymus atrophy owing to a developmental defect of T-lymphoid cells. Clearance of apoptotic cells by macrophages was impaired in both liver and thymus of PSR-/- embryos. However, this did not induce up-regulation of inflammatory cytokines. These results indicate that during embryonic development, PSR-mediated apoptotic cell uptake is required for definitive erythropoiesis and T lymphopoiesis, independently of the prevention of inflammatory responses. (Blood. 2004;103:3362-3364)

scholarly journals The amino acid sensor GCN2 inhibits inflammatory responses to apoptotic cells promoting tolerance and suppressing systemic autoimmunity

2015 ◽  
Vol 112 (34) ◽  
pp. 10774-10779 ◽  
Author(s):  
Buvana Ravishankar ◽  
Haiyun Liu ◽  
Rahul Shinde ◽  
Kapil Chaudhary ◽  
Wei Xiao ◽  
...  
Keyword(s):  
Cell Activation ◽  
Immune Cell ◽  
Inflammatory Responses ◽  
Apoptotic Cell ◽  
Metabolic Stress ◽  
Tolerance Induction ◽  
Apoptotic Cells ◽  
Cell Clearance

Efficient apoptotic cell clearance and induction of immunologic tolerance is a critical mechanism preventing autoimmunity and associated pathology. Our laboratory has reported that apoptotic cells induce tolerance by a mechanism dependent on the tryptophan catabolizing enzyme indoleamine 2,3 dioxygenase 1 (IDO1) in splenic macrophages (MΦ). The metabolic-stress sensing protein kinase GCN2 is a primary downstream effector of IDO1; thus, we tested its role in apoptotic cell-driven immune suppression. In vitro, expression of IDO1 in MΦs significantly enhanced apoptotic cell-driven IL-10 and suppressed IL-12 production in a GCN2-dependent mechanism. Suppression of IL-12 protein production was due to attenuation of IL-12 mRNA association with polyribosomes inhibiting translation while IL-10 mRNA association with polyribosomes was not affected. In vivo, apoptotic cell challenge drove a rapid, GCN2-dependent stress response in splenic MΦs with increased IL-10 and TGF-β production, whereas myeloid-specific deletion of GCN2 abrogated regulatory cytokine production with provocation of inflammatory T-cell responses to apoptotic cell antigens and failure of long-tolerance induction. Consistent with a role in prevention of apoptotic cell driven autoreactivity, myeloid deletion of GCN2 in lupus-prone mice resulted in increased immune cell activation, humoral autoimmunity, renal pathology, and mortality. In contrast, activation of GCN2 with an agonist significantly reduced anti-DNA autoantibodies and protected mice from disease. Thus, this study implicates a key role for GCN2 signals in regulating the tolerogenic response to apoptotic cells and limiting autoimmunity.

scholarly journals Antiinflammatory Effects of CD95 Ligand (FasL)-induced Apoptosis

1998 ◽  
Vol 188 (5) ◽  
pp. 887-896 ◽  
Author(s):  
Yakun Gao ◽  
John M. Herndon ◽  
Hui Zhang ◽  
Thomas S. Griffith ◽  
Thomas A. Ferguson
Keyword(s):  
Cell Death ◽  
Apoptotic Cell ◽  
Apoptotic Cell Death ◽  
Lymphoid Cells ◽  
Apoptotic Cells ◽  
Immune Deviation ◽  
Inflammatory Reactions ◽  
Cd95 Ligand ◽  
Induced Apoptosis

Apoptosis is critical to homeostasis of multicellular organisms. In immune privileged sites such as the eye, CD95 ligand (FasL)-induced apoptosis controls dangerous inflammatory reactions that can cause blindness. Recently, we demonstrated that apoptotic cell death of inflammatory cells was a prerequisite for the induction of immune deviation after antigen presentation in the eye. In this report, we examine the mechanism by which this takes place. Our results show that Fas- mediated apoptosis of lymphoid cells leads to rapid production of interleukin (IL)-10 in these cells. The apoptotic cells containing IL-10 are responsible for the activation of immune deviation through interaction with antigen-presenting cells (APC). In support of this, we found that apoptotic cells from IL-10+/+ animals fed to APC in vitro promote Th2 cell differentiation, whereas apoptotic IL-10−/− cells, as well as nonapoptotic cells, favor Th1 induction. Thus, apoptotic cell death and tolerance are linked through the production of an antiinflammatory cytokine to prevent dangerous and unwanted immune responses that might compromise organ integrity.

Fetuin/α2-HS glycoprotein enhances phagocytosis of apoptotic cells and macropinocytosis by human macrophages

2003 ◽  
Vol 105 (3) ◽  
pp. 273-278 ◽  
Author(s):  
Hubertus P. A. JERSMANN ◽  
Ian DRANSFIELD ◽  
Simon P. HART
Keyword(s):  
Inflammatory Diseases ◽  
Apoptotic Cell ◽  
Human Peripheral Blood ◽  
Peripheral Blood Monocyte ◽  
Cell Uptake ◽  
Apoptotic Cells ◽  
Cell Clearance ◽  
Human Peripheral Blood Monocyte

Inflammatory diseases are associated with reduced serum concentrations of α2-HS glycoprotein (the human homologue of bovine fetuin), but the role of fetuin in inflammation is poorly understood. We hypothesized that fetuin may influence the resolution of inflammation by modulating the phagocytosis of apoptotic cells by macrophages. Using an in vitro flow cytometry-based phagocytosis assay, we investigated the role of fetuin in apoptotic cell clearance. Bovine fetuin and human α2-HS glycoprotein significantly augmented the phagocytosis of apoptotic cells by human peripheral blood monocyte-derived macrophages, whereas the control proteins BSA, sialylated BSA and asialofetuin were ineffective. The enhancement of phagocytosis was concentration-dependent, and required the presence of intact fetuin at the time of interaction between macrophages and apoptotic cells. Fetuin also substantially increased the uptake of labelled dextran 70000 by macrophages, which occurs by macropinocytosis, suggesting that this may be one of the mechanisms utilized for apoptotic cell uptake.

scholarly journals Glucocorticoid-mediated regulation of granulocyte apoptosis and macrophage phagocytosis of apoptotic cells: implications for the resolution of inflammation

2003 ◽  
Vol 178 (1) ◽  
pp. 29-36 ◽  
Author(s):  
SJ Heasman ◽  
KM Giles ◽  
C Ward ◽  
AG Rossi ◽  
C Haslett ◽  
...  
Keyword(s):  
Acute Inflammation ◽  
Inflammatory Responses ◽  
Apoptotic Cell ◽  
Apoptotic Cells ◽  
Glucocorticoid Treatment ◽  
Resolution Of Inflammation ◽  
Inflammatory Conditions ◽  
Macrophage Phagocytosis ◽  
Cell Clearance

Glucocorticoids represent one of the most effective clinical treatments for a range of inflammatory conditions, including severe acute inflammation. Although glucocorticoids are known to affect processes involved in the initiation of inflammation, the influence of glucocorticoids on the mechanisms by which acute inflammation normally resolves have received less attention. Apoptosis of granulocytes present at inflamed sites leads to their rapid recognition and internalisation by macrophages, a process which may be important for resolution of inflammation. However, if clearance of either eosinophils or neutrophils is impaired, these cells rapidly undergo secondary necrosis leading to release of pro-inflammatory mediators from the phagocyte, potentially prolonging inflammatory responses. Physiologically relevant concentrations of glucocorticoids accelerate eosinophil apoptosis whilst delaying neutrophil apoptosis during in vitro culture. Here we discuss key pathways regulating the granulocyte apoptotic programme and summarise the effects of glucocorticoids on monocyte differentiation and the consequent changes to apoptotic cell clearance capacity. Definition of the mechanisms underlying resolution of inflammatory responses following glucocorticoid treatment may unveil new targets for modulation of inflammatory disease, allowing co-ordinated augmentation of granulocyte apoptosis together with increased macrophage capacity for clearance of apoptotic cells.

scholarly journals Apoptotic cells induce CD103 expression and immunoregulatory function in myeloid dendritic cell precursors through integrin αv and TGF-β activation

2020 ◽  
Author(s):  
Ailiang Zhang ◽  
Helena Paidassi ◽  
Adam Lacy-Hulbert ◽  
John Savill
Keyword(s):  
Ex Vivo ◽  
Apoptotic Cell ◽  
Cell Interaction ◽  
Apoptotic Cells ◽  
Intestinal Epithelial ◽  
Mesenteric Lymph Nodes ◽  
Murine Bone Marrow ◽  
Enhanced Expression ◽  
Tgf Β1

In the mammalian gut CD103+ve myeloid DCs are known to suppress inflammation threatened by luminal bacteria, but stimuli driving DC precursor differentiation towards this beneficial phenotype are incompletely understood. We isolated CD11+ve DCs from mesenteric lymph nodes (MLNs) of healthy mice; CD103+ve DCs were 8-24 folds more likely than CD103-ve DCs to exhibit extensive of prior phagocytosis of apoptotic intestinal epithelial cells. However, CD103+ve and CD103-ve MLN DCs exhibited similar ex vivo capacity to ingest apoptotic cells, indicating that apoptotic cells might drive immature DC differentiation towards the CD103+ve phenotype. When cultured with apoptotic cells, myeloid DC precursors isolated from murine bone marrow and characterised as lineage-ve CD103-ve, displayed enhanced expression of CD103 and β8 integrin and acquired increased capacity to induce Tregs after 7d in vitro. However, DC precursors isolated from α v -tie2 mice lacking α v integrins in the myeloid line exhibited reduced binding of apoptotic cells and complete deficiency in the capacity of apoptotic cells and/or latent TGF-β1 to enhance CD103 expression in culture, whereas active TGF-β1 increased DC precursor CD103 expression irrespective of α v expression. Fluorescence microscopy revealed clustering of α v integrin chains and latent TGF-β1 at points of contact between DC precursors and apoptotic cells. We conclude that myeloid DC precursors can deploy α v integrin to orchestrate binding of apoptotic cells, activation of latent TGF-β1 and acquisition of the immunoregulatory CD103+ve β8+ve DC phenotype. This implies that a hitherto unrecognised consequence of apoptotic cell interaction with myeloid phagocytes is programming that prevents inflammation.

scholarly journals Overexposure to apoptosis via disrupted glial specification perturbs Drosophila macrophage function and reveals roles of the CNS during injury

2020 ◽  
Author(s):  
Emma Louise Armitage ◽  
Hannah Grace Roddie ◽  
Iwan Robert Evans
Keyword(s):  
Inflammatory Responses ◽  
Apoptotic Cell ◽  
Calcium Waves ◽  
Apoptotic Cells ◽  
Phagocytic Cells ◽  
Macrophage Function ◽  
Apoptotic Cell Clearance ◽  
Cell Clearance ◽  
Wound Responses

AbstractApoptotic cell clearance by phagocytes is a fundamental process during development, homeostasis and the resolution of inflammation. However, the demands placed on phagocytic cells such as macrophages by this process, and the limitations these interactions impose on subsequent cellular behaviours are not yet clear. Here we seek to understand how apoptotic cells affect macrophage function in the context of a genetically-tractable Drosophila model in which macrophages encounter excessive amounts of apoptotic cells. We show that loss of the glial transcription factor repo, and corresponding removal of the contribution these cells make to apoptotic cell clearance, causes macrophages in the developing embryo to be challenged with large numbers of apoptotic cells. As a consequence, macrophages become highly vacuolated with cleared apoptotic cells and their developmental dispersal and migration is perturbed. We also show that the requirement to deal with excess apoptosis caused by a loss of repo function leads to impaired inflammatory responses to injury. However, in contrast to migratory phenotypes, defects in wound responses cannot be rescued by preventing apoptosis from occurring within a repo mutant background. In investigating the underlying cause of these impaired inflammatory responses, we demonstrate that wound-induced calcium waves propagate into surrounding tissues, including neurons and glia of the ventral nerve cord, which exhibit striking calcium waves on wounding, revealing a previously unanticipated contribution of these cells during responses to injury. Taken together these results demonstrate important insights into macrophage biology and how repo mutants can be used to study macrophage-apoptotic cell interactions in the fly embryo.Furthermore, this work shows how these multipurpose cells can be ‘overtasked’ to the detriment of their other functions, alongside providing new insights into which cells govern macrophage responses to injury in vivo.

scholarly journals A Biomimetic Drug Delivery System Targeting Tumor Hypoxia in Triple-Negative Breast Cancers

2020 ◽  
Vol 10 (3) ◽  
pp. 1075 ◽  
Author(s):  
Katyayani Tatiparti ◽  
Mohd Ahmar Rauf ◽  
Samaresh Sau ◽  
Arun K. Iyer
Keyword(s):  
Triple Negative ◽  
Apoptotic Cell ◽  
Tumor Hypoxia ◽  
Chemical Properties ◽  
Treatment Resistance ◽  
Cell Killing ◽  
Cell Uptake ◽  
Cancer Drug ◽  
Breast Cancers

Triple-negative breast cancer (TNBC) is amongst the most challenging tumor subtypes because it presents itself without the estrogen, progesterone, and HER2 receptors. Hence, assessing new markers is an essential requirement for enhancing its targeted treatment. The survival of TNBC relies upon the advancement of hypoxia that contributes to treatment resistance, immune response resistance, and tumor stroma arrangement. Here, we explored bovine serum albumin (BSA) nanoparticle encapsulating the anti-cancer drug Paclitaxel (PTX) for cell-killing mediated by tumor hypoxia. For targeting hypoxia, we conjugated Acetazolamide (ATZ) with BSA nanoparticle that encapsulated PTX (referred hereon as BSA-PTX-ATZ) utilizing copper-free click chemistry, specifically the Strain-Promoted Alkyne Azide Cycloaddition (SPAAC). The in-vitro cell killing study uncovered that BSA-PTX-ATZ is more productive contrasted with free PTX. The evaluations of the physio-chemical properties of BSA-PTX-ATZ proves that the shelf-life is approximately two months when stored either at room or freezing temperatures or under refrigerated conditions. There is no leakage of PTX from the formulation during that period, while their nanoparticulate nature remained undisturbed. The BSA-PTX-ATZ nanoparticles indicated altogether higher cell killing in hypoxic conditions contrasted with normoxia proposing the hypoxia-mediated delivery mechanism of the activity of the formulation. Higher cell uptake found with fluorescent-marked BSA-PTX-ATZ shows CA-IX mediated cell uptake, substantiated by the prominent apoptotic cell death contrasted with free PTX.

scholarly journals Persistence of apoptotic cells without autoimmune disease or inflammation in CD14−/− mice

2004 ◽  
Vol 167 (6) ◽  
pp. 1161-1170 ◽  
Author(s):  
Andrew Devitt ◽  
Kate G. Parker ◽  
Carol Anne Ogden ◽  
Ceri Oldreive ◽  
Michael F. Clay ◽  
...  
Keyword(s):  
Autoimmune Disease ◽  
Apoptotic Cell ◽  
Apoptotic Cells ◽  
Autoantibody Production ◽  
Apoptotic Cell Clearance ◽  
Cell Clearance ◽  
Surface Receptor ◽  
Anti Inflammatory

Interaction of macrophages with apoptotic cells involves multiple steps including recognition, tethering, phagocytosis, and anti-inflammatory macrophage responses. Defective apoptotic cell clearance is associated with pathogenesis of autoimmune disease. CD14 is a surface receptor that functions in vitro in the removal of apoptotic cells by human and murine macrophages, but its mechanism of action has not been defined. Here, we demonstrate that CD14 functions as a macrophage tethering receptor for apoptotic cells. Significantly, CD14−/− macrophages in vivo are defective in clearing apoptotic cells in multiple tissues, suggesting a broad role for CD14 in the clearance process. However, the resultant persistence of apoptotic cells does not lead to inflammation or increased autoantibody production, most likely because, as we show, CD14−/− macrophages retain the ability to generate anti-inflammatory signals in response to apoptotic cells. We conclude that CD14 plays a broad tethering role in apoptotic cell clearance in vivo and that apoptotic cells can persist in the absence of proinflammatory consequences.

scholarly journals Interaction of Apoptotic Cells with Macrophages Upregulates COX-2/PGE2and HGF Expression via a Positive Feedback Loop

2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Ji Yeon Byun ◽  
Young-So Youn ◽  
Ye-Ji Lee ◽  
Youn-Hee Choi ◽  
So-Yeon Woo ◽  
...  
Keyword(s):  
Positive Feedback ◽  
Tissue Repair ◽  
Feedback Loop ◽  
Apoptotic Cell ◽  
Raw 264.7 Cells ◽  
Apoptotic Cells ◽  
Positive Feedback Loop ◽  
Cox 2

Recognition of apoptotic cells by macrophages is crucial for resolution of inflammation, immune tolerance, and tissue repair. Cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) and hepatocyte growth factor (HGF) play important roles in the tissue repair process. We investigated the characteristics of macrophage COX-2 and PGE2expression mediated by apoptotic cells and then determined how macrophages exposed to apoptotic cellsin vitroandin vivoorchestrate the interaction between COX-2/PGE2and HGF signaling pathways. Exposure of RAW 264.7 cells and primary peritoneal macrophages to apoptotic cells resulted in induction of COX-2 and PGE2. The COX-2 inhibitor NS-398 suppressed apoptotic cell-induced PGE2production. Both NS-398 and COX-2-siRNA, as well as the PGE2receptor EP2 antagonist, blocked HGF expression in response to apoptotic cells. In addition, the HGF receptor antagonist suppressed increases in COX-2 and PGE2induction. Thein vivorelevance of the interaction between the COX-2/PGE2and HGF pathways through a positive feedback loop was shown in cultured alveolar macrophages followingin vivoexposure of bleomycin-stimulated lungs to apoptotic cells. Our results demonstrate that upregulation of the COX-2/PGE2and HGF in macrophages following exposure to apoptotic cells represents a mechanism for mediating the anti-inflammatory and antifibrotic consequences of apoptotic cell recognition.

scholarly journals Clarifying the role of Stat5 in lymphoid development and Abelson-induced transformation

Blood ◽  
2006 ◽  
Vol 107 (12) ◽  
pp. 4898-4906 ◽  
Author(s):  
Andrea Hoelbl ◽  
Boris Kovacic ◽  
Marc A. Kerenyi ◽  
Olivia Simma ◽  
Wolfgang Warsch ◽  
...  
Keyword(s):  
B Cell ◽  
Fetal Liver ◽  
Transgenic Animals ◽  
Cell Receptor ◽  
Lymphoid Cells ◽  
In Vitro Assays ◽  
Cell Stage ◽  
Lymphoid Development ◽  
B Lymphoid

AbstractThe Stat5 transcription factors Stat5a and Stat5b have been implicated in lymphoid development and transformation. Most studies have employed Stat5a/b-deficient mice where gene targeting disrupted the first protein-coding exon, resulting in the expression of N-terminally truncated forms of Stat5a/b (Stat5a/bΔN/ΔN mice). We have now reanalyzed lymphoid development in Stat5a/bnull/null mice having a complete deletion of the Stat5a/b gene locus. The few surviving Stat5a/bnull/null mice lacked CD8+ T lymphocytes. A massive reduction of CD8+ T cells was also found in Stat5a/bfl/fllck-cre transgenic animals. While γδ T-cell receptor–positive (γδTCR+) cells were expressed at normal levels in Stat5a/bΔN/ΔN mice, they were completely absent in Stat5a/bnull/null animals. Moreover, B-cell maturation was abrogated at the pre–pro-B-cell stage in Stat5a/bnull/null mice, whereas Stat5a/bΔN/ΔN B-lymphoid cells developed to the early pro-B-cell stage. In vitro assays using fetal liver-cell cultures confirmed this observation. Most strikingly, Stat5a/bnull/null cells were resistant to transformation and leukemia development induced by Abelson oncogenes, whereas Stat5a/bΔN/ΔN-derived cells readily transformed. These findings show distinct lymphoid defects for Stat5a/bΔN/ΔN and Stat5a/bnull/null mice and define a novel functional role for the N-termini of Stat5a/b in B-lymphoid transformation.

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