scholarly journals Distinct Modes of Macrophage Recognition for Apoptotic and Necrotic Cells Are Not Specified Exclusively by Phosphatidylserine Exposure

2001 ◽  
Vol 12 (4) ◽  
pp. 919-930 ◽  
Author(s):  
Regina E. Cocco ◽  
David S. Ucker
Keyword(s):  
Macrophage Activation ◽  
Apoptotic Cells ◽  
Activated Macrophages ◽  
Necrotic Cell ◽  
Phagocytic Cells ◽  
Marked Contrast ◽  
Proinflammatory Responses ◽  
A Cell ◽  
Dying Cells ◽  
Specific Ligand

The distinction between physiological (apoptotic) and pathological (necrotic) cell deaths reflects mechanistic differences in cellular disintegration and is of functional significance with respect to the outcomes that are triggered by the cell corpses. Mechanistically, apoptotic cells die via an active and ordered pathway; necrotic deaths, conversely, are chaotic and passive. Macrophages and other phagocytic cells recognize and engulf these dead cells. This clearance is believed to reveal an innate immunity, associated with inflammation in cases of pathological but not physiological cell deaths. Using objective and quantitative measures to assess these processes, we find that macrophages bind and engulf native apoptotic and necrotic cells to similar extents and with similar kinetics. However, recognition of these two classes of dying cells occurs via distinct and noncompeting mechanisms. Phosphatidylserine, which is externalized on both apoptotic and necrotic cells, is not a specific ligand for the recognition of either one. The distinct modes of recognition for these different corpses are linked to opposing responses from engulfing macrophages. Necrotic cells, when recognized, enhance proinflammatory responses of activated macrophages, although they are not sufficient to trigger macrophage activation. In marked contrast, apoptotic cells profoundly inhibit phlogistic macrophage responses; this represents a cell-associated, dominant-acting anti-inflammatory signaling activity acquired posttranslationally during the process of physiological cell death.

scholarly journals TNFα inhibits apoptotic cell clearance in the lung, exacerbating acute inflammation

2009 ◽  
Vol 297 (4) ◽  
pp. L586-L595 ◽  
Author(s):  
Valeria M. Borges ◽  
R. William Vandivier ◽  
Kathleen A. McPhillips ◽  
Jennifer A. Kench ◽  
Konosuke Morimoto ◽  
...  
Keyword(s):  
Lung Injury ◽  
Apoptotic Cell ◽  
Apoptotic Cells ◽  
Neutrophil Accumulation ◽  
Cell Recruitment ◽  
Apoptotic Cell Clearance ◽  
Persistent Inflammation ◽  
Cell Clearance ◽  
Proinflammatory Responses ◽  
Dying Cells

Efficient removal of apoptotic cells is essential for resolution of inflammation. Failure to clear dying cells can exacerbate lung injury and lead to persistent inflammation and autoimmunity. Here we show that TNFα blocks apoptotic cell clearance by alveolar macrophages and leads to proinflammatory responses in the lung. Compared with mice treated with intratracheal TNFα or exogenous apoptotic cells, mice treated with the combination of TNFα plus apoptotic cells demonstrated reduced apoptotic cell clearance from the lungs and increased recruitment of inflammatory leukocytes to the air spaces. Treatment with intratracheal TNFα had no effect on the removal of exogenous apoptotic cells from the lungs of TNFα receptor-1 (p55) and -2 (p75) double mutant mice and no effect on leukocyte recruitment. Bronchoalveolar lavage from mice treated with TNFα plus apoptotic cells contained increased levels of proinflammatory cytokines IL-6, KC, and MCP-1, but exhibited no change in levels of anti-inflammatory cytokines IL-10 and TGF-β. Administration of TNFα plus apoptotic cells during LPS-induced lung injury augmented neutrophil accumulation and proinflammatory cytokine production. These findings suggest that the presence of TNFα in the lung can alter the response of phagocytes to apoptotic cells leading to inflammatory cell recruitment and proinflammatory mediator production.

scholarly journals Apoptosis-induced FGF signalling promotes non-cell autonomous resistance to cell death

2020 ◽  
Author(s):  
Florian J. Bock ◽  
Catherine Cloix ◽  
Desiree Zerbst ◽  
Stephen W.G. Tait
Keyword(s):  
Cell Death ◽  
Apoptotic Cells ◽  
Potential Danger ◽  
Fgf Receptor ◽  
A Cell ◽  
Response To Stress ◽  
Cancer Types ◽  
Fgf Signalling ◽  
Dying Cells ◽  
Worse Prognosis

AbstractDamaged or superfluous cells are often eliminated by apoptosis. Although a cell-autonomous process, apoptotic cells communicate with their environment in different ways. However, the extent to which apoptotic cells alerting their neighbours to potential danger is unclear. Addressing this question, here we describe a mechanism whereby dying cells can promote survival of neighbouring cells. We find that during apoptosis, cells release the growth factor FGF2, leading to MEK/ERK-dependent transcriptional upregulation of pro-survival BCL-2 proteins in a non-cell autonomous manner. This transient upregulation of prosurvival BCL-2 proteins in turn can protect neighbouring cells from apoptosis. Accordingly, we find in certain cancer types a correlation between FGF-signalling, BCL-2 expression and worse prognosis. Importantly, either co-treatment with FGF-receptor inhibitors or removal of apoptotic stress restores apoptotic sensitivity. These data reveal a pathway by which dying cells can increase resistance to cell death in surrounding cells. Beyond mediating cytotoxic drug resistance, this process may serve additional roles, for instance limiting tissue damage in response to stress.

scholarly journals Cell Death in the Tumor Microenvironment: Implications for Cancer Immunotherapy

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2207
Author(s):  
Varsha Gadiyar ◽  
Kevin C. Lahey ◽  
David Calianese ◽  
Connor Devoe ◽  
Dhriti Mehta ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Immune Escape ◽  
Apoptotic Cells ◽  
Phagocytic Cells ◽  
Purine Nucleotides ◽  
Compensatory Proliferation ◽  
Sphingosine 1 Phosphate ◽  
Homeostatic Function ◽  
Membrane Bound ◽  
Dying Cells

The physiological fate of cells that die by apoptosis is their prompt and efficient removal by efferocytosis. During these processes, apoptotic cells release intracellular constituents that include purine nucleotides, lysophosphatidylcholine (LPC), and Sphingosine-1-phosphate (S1P) that induce migration and chemo-attraction of phagocytes as well as mitogens and extracellular membrane-bound vesicles that contribute to apoptosis-induced compensatory proliferation and alteration of the extracellular matrix and the vascular network. Additionally, during efferocytosis, phagocytic cells produce a number of anti-inflammatory and resolving factors, and, together with apoptotic cells, efferocytic events have a homeostatic function that regulates tissue repair. These homeostatic functions are dysregulated in cancers, where, aforementioned events, if not properly controlled, can lead to cancer progression and immune escape. Here, we summarize evidence that apoptosis and efferocytosis are exploited in cancer, as well as discuss current translation and clinical efforts to harness signals from dying cells into therapeutic strategies.

scholarly journals P115 RhoGEF and microtubules decide the direction apoptotic cells extrude from an epithelium

2009 ◽  
Vol 186 (5) ◽  
pp. 693-702 ◽  
Author(s):  
Gloria Slattum ◽  
Karen M. McGee ◽  
Jody Rosenblatt
Keyword(s):  
Apoptotic Cell ◽  
Extrusion Direction ◽  
Apoptotic Cells ◽  
Epithelial Barrier Function ◽  
Apical Extrusion ◽  
A Cell ◽  
Microtubule Reorientation ◽  
Epithelial Sheet ◽  
P115 Rhogef ◽  
Dying Cells

To preserve epithelial barrier function, dying cells are squeezed out of an epithelium by “apoptotic cell extrusion.” Specifically, a cell destined for apoptosis signals its live neighboring epithelial cells to form and contract a ring of actin and myosin II that squeezes the dying cell out of the epithelial sheet. Although most apoptotic cells extrude apically, we find that some exit basally. Localization of actin and myosin IIA contraction dictates the extrusion direction: basal extrusion requires circumferential contraction of neighboring cells at their apices, whereas apical extrusion also requires downward contraction along the basolateral surfaces. To activate actin/myosin basolaterally, microtubules in neighboring cells reorient and target p115 RhoGEF to this site. Preventing microtubule reorientation restricts contraction to the apex, driving extrusion basally. Extrusion polarity has important implications for tumors where apoptosis is blocked but extrusion is not, as basal extrusion could enable these cells to initiate metastasis.

scholarly journals The adjuvant effect of Corynebacterium parvum: T-cell dependence of macrophage activation.

1977 ◽  
Vol 145 (1) ◽  
pp. 45-57 ◽  
Author(s):  
V S Sljivić ◽  
S R Watson
Keyword(s):  
T Cell ◽  
Macrophage Activation ◽  
Peritoneal Macrophages ◽  
Activated Macrophages ◽  
Spleen Cells ◽  
Adjuvant Effect ◽  
Corynebacterium Parvum ◽  
A Cell ◽  
Time Of Administration

Splenic and peritoneal macrophages from mice treated with Corynebacterium parvum enhanced the antibody response in vitro of normal nonadherent spleen cells to SRBC, but not to DNP-POL. This enhancement was dependent on the dose and time of administration of C. parvum and could be abrogated by pretreatment with carrageenan. Macrophages from T-cell-depleted mice failed to enhance the response, but this ability was restored if the mice had been reconstituted with purified T lymphocytes. Macrophages that are activated by C. parvum are a resident nondividing population. It is postulated that activated macrophages, capable of enhancing antibody responses to T-cell-dependent antigens, arise through a cell-mediated reaction to C. parvum.

scholarly journals In vivo targeting of lentiviral vectors pseudotyped with the Tupaia paramyxovirus H glycoprotein bearing a cell-specific ligand

2021 ◽  
Author(s):  
Takele Argaw ◽  
Michael P. Marino ◽  
Andrew Timmons ◽  
Lindsey Eldridge ◽  
Kazuyo Takeda ◽  
...  
Keyword(s):  
Lentiviral Vectors ◽  
A Cell ◽  
Specific Ligand

scholarly journals Arginase in Parasitic Infections: Macrophage Activation, Immunosuppression, and Intracellular Signals

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Cinthia C. Stempin ◽  
Laura R. Dulgerian ◽  
Vanina V. Garrido ◽  
Fabio M. Cerban
Keyword(s):  
Macrophage Activation ◽  
Transforming Growth Factor ◽  
Parasite Clearance ◽  
Alternative Activation ◽  
Parasitic Infections ◽  
Activated Macrophages ◽  
Proinflammatory Response ◽  
Alternatively Activated Macrophages ◽  
Arginase 1

A type 1 cytokine-dependent proinflammatory response inducing classically activated macrophages (CaMϕs) is crucial for parasite control during protozoan infections but can also contribute to the development of immunopathological disease symptoms. Type 2 cytokines such as IL-4 and IL-13 antagonize CaMϕs inducing alternatively activated macrophages (AaMϕs) that upregulate arginase-1 expression. During several infections, induction of arginase-1-macrophages was showed to have a detrimental role by limiting CaMϕ-dependent parasite clearance and promoting parasite proliferation. Additionally, the role of arginase-1 in T cell suppression has been explored recently. Arginase-1 can also be induced by IL-10 and transforming growth factor-β(TGF-β) or even directly by parasites or parasite components. Therefore, generation of alternative activation states of macrophages could limit collateral tissue damage because of excessive type 1 inflammation. However, they affect disease outcome by promoting parasite survival and proliferation. Thus, modulation of macrophage activation may be instrumental in allowing parasite persistence and long-term host survival.

Glycerol-3-phosphate acyltransferases 3 and 4 direct glycerolipid synthesis and affect functionality in activated macrophages

2019 ◽  
Vol 476 (1) ◽  
pp. 85-99 ◽  
Author(s):  
Ivana Y. Quiroga ◽  
Magali Pellon-Maison ◽  
Amanda L. Suchanek ◽  
Rosalind A. Coleman ◽  
Maria R. Gonzalez-Baro
Keyword(s):  
Lipid Accumulation ◽  
Macrophage Activation ◽  
Lipid A ◽  
Inflammatory Responses ◽  
Activated Macrophages ◽  
Phagocytic Capacity ◽  
Activity Increase ◽  
Cytokines And Chemokines ◽  
Lipid Mass ◽  
Glycerolipid Synthesis

AbstractMacrophage classical M1 activation via TLR4 triggers a variety of responses to achieve the elimination of foreign pathogens. During this process, there is also an increase in lipid droplets which contain large quantities of triacylglycerol (TAG) and phospholipid (PL). The functional consequences of this increment in lipid mass are poorly understood. Here, we studied the contribution of glycerolipid synthesis to lipid accumulation, focusing specifically on the first and rate-limiting enzyme of the pathway: glycerol-3-phosphate acyltransferase (GPAT). Using bone marrow-derived macrophages (BMDMs) treated with Kdo2-lipid A, we showed that glycerolipid synthesis is induced during macrophage activation. GPAT4 protein level and GPAT3/GPAT4 enzymatic activity increase during this process, and these two isoforms were required for the accumulation of cell TAG and PL. The phagocytic capacity of Gpat3−/− and Gpat4−/− BMDM was impaired. Additionally, inhibiting fatty acid β-oxidation reduced phagocytosis only partially, suggesting that lipid accumulation is not necessary for the energy requirements for phagocytosis. Finally, Gpat4−/− BMDM expressed and released more pro-inflammatory cytokines and chemokines after macrophage activation, suggesting a role for GPAT4 in suppressing inflammatory responses. Together, these results provide evidence that glycerolipid synthesis directed by GPAT4 is important for the attenuation of the inflammatory response in activated macrophages.

scholarly journals From Flies to Men: ROS and the NADPH Oxidase in Phagocytes

2021 ◽  
Vol 9 ◽  
Author(s):  
Zohreh Mansoori Moghadam ◽  
Philipp Henneke ◽  
Julia Kolter
Keyword(s):  
Defense Mechanisms ◽  
Phagocytic Cells ◽  
Mitochondrial Ros ◽  
Transport Chain ◽  
A Cell ◽  
Health And Disease ◽  
Ros Formation ◽  
Immunological Process ◽  
Lower Complexity ◽  
Bacteria And Fungi

The cellular formation of reactive oxygen species (ROS) represents an evolutionary ancient antimicrobial defense system against microorganisms. The NADPH oxidases (NOX), which are predominantly localized to endosomes, and the electron transport chain in mitochondria are the major sources of ROS. Like any powerful immunological process, ROS formation has costs, in particular collateral tissue damage of the host. Moreover, microorganisms have developed defense mechanisms against ROS, an example for an arms race between species. Thus, although NOX orthologs have been identified in organisms as diverse as plants, fruit flies, rodents, and humans, ROS functions have developed and diversified to affect a multitude of cellular properties, i.e., far beyond direct antimicrobial activity. Here, we focus on the development of NOX in phagocytic cells, where the so-called respiratory burst in phagolysosomes contributes to the elimination of ingested microorganisms. Yet, NOX participates in cellular signaling in a cell-intrinsic and -extrinsic manner, e.g., via the release of ROS into the extracellular space. Accordingly, in humans, the inherited deficiency of NOX components is characterized by infections with bacteria and fungi and a seemingly independently dysregulated inflammatory response. Since ROS have both antimicrobial and immunomodulatory properties, their tight regulation in space and time is required for an efficient and well-balanced immune response, which allows for the reestablishment of tissue homeostasis. In addition, distinct NOX homologs expressed by non-phagocytic cells and mitochondrial ROS are interlinked with phagocytic NOX functions and thus affect the overall redox state of the tissue and the cellular activity in a complex fashion. Overall, the systematic and comparative analysis of cellular ROS functions in organisms of lower complexity provides clues for understanding the contribution of ROS and ROS deficiency to human health and disease.

scholarly journals Chemokines as phosphatidylserine-bound ‘find-me’ signals in apoptotic cell clearance

2020 ◽  
Author(s):  
Sergio M. Pontejo ◽  
Philip M. Murphy
Keyword(s):  
Extracellular Vesicles ◽  
Chemokine Receptors ◽  
Apoptotic Cell ◽  
Apoptotic Cells ◽  
Anionic Phospholipid ◽  
Apoptotic Cell Clearance ◽  
Cell Clearance ◽  
Cell Plasma ◽  
Signal Activity ◽  
Dying Cells

AbstractChemokines are positively charged cytokines that attract leukocytes by binding to anionic glycosaminoglycans (GAGs) on endothelial cells for efficient presentation to leukocyte G protein-coupled receptors (GPCRs). The atypical chemokine CXCL16 has been reported to also bind the anionic phospholipid phosphatidylserine (PS), but the biological relevance of this interaction remains poorly understood. Here we demonstrate that PS binding is in fact a widely shared property of chemokine superfamily members that, like GAG binding, induces chemokine oligomerization. PS is an essential phospholipid of the inner leaflet of the healthy cell plasma membrane but it is exposed in apoptotic cells to act as an ‘eat-me’ signal that promotes engulfment of dying cells by phagocytes. We found that chemokines can bind PS in pure form as well as in the context of liposomes and on the surface of apoptotic cells and extracellular vesicles released by apoptotic cells, which are known to act as ‘find-me’ signals that chemoattract phagocytes during apoptotic cell clearance. Importantly, we show that GAGs are severely depleted from the surface of apoptotic cells and that extracellular vesicles extracted from apoptotic mouse thymus bind endogenous thymic chemokines and activate cognate chemokine receptors. Together these results indicate that chemokines tethered to surface-exposed PS may be responsible for the chemotactic and find-me signal activity previously attributed to extracellular vesicles, and that PS may substitute for GAGs as the anionic scaffold that regulates chemokine oligomerization and presentation to GPCRs on the GAG-deficient membranes of apoptotic cells and extracellular vesicles. Here, we present a new mechanism by which extracellular vesicles, currently recognized as essential agents for intercellular communication in homeostasis and disease, can transport signaling cytokines.

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