scholarly journals Dictyostelium cell death

2003 ◽  
Vol 160 (7) ◽  
pp. 1105-1114 ◽  
Author(s):  
Jean-Pierre Levraud ◽  
Myriam Adam ◽  
Marie-Françoise Luciani ◽  
Chantal de Chastellier ◽  
Richard L. Blanton ◽  
...  
Keyword(s):  
Cell Death ◽  
Time Lapse ◽  
Death Process ◽  
Cellulose Synthesis ◽  
Dictyostelium Cell ◽  
Round Cell ◽  
Cell Death Pathway ◽  
Cell Transition ◽  
Vacuolar Cell

Cell death in the stalk of Dictyostelium discoideum, a prototypic vacuolar cell death, can be studied in vitro using cells differentiating as a monolayer. To identify early events, we examined potentially dying cells at a time when the classical signs of Dictyostelium cell death, such as heavy vacuolization and membrane lesions, were not yet apparent. We observed that most cells proceeded through a stereotyped series of differentiation stages, including the emergence of “paddle” cells showing high motility and strikingly marked subcellular compartmentalization with actin segregation. Paddle cell emergence and subsequent demise with paddle-to-round cell transition may be critical to the cell death process, as they were contemporary with irreversibility assessed through time-lapse videos and clonogenicity tests. Paddle cell demise was not related to formation of the cellulose shell because cells where the cellulose-synthase gene had been inactivated underwent death indistinguishable from that of parental cells. A major subcellular alteration at the paddle-to-round cell transition was the disappearance of F-actin. The Dictyostelium vacuolar cell death pathway thus does not require cellulose synthesis and includes early actin rearrangements (F-actin segregation, then depolymerization), contemporary with irreversibility, corresponding to the emergence and demise of highly polarized paddle cells.

scholarly journals Genetically encoded cell-death indicators (GEDI) to detect an early irreversible commitment to neurodegeneration

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jeremy W. Linsley ◽  
Kevan Shah ◽  
Nicholas Castello ◽  
Michelle Chan ◽  
Dominik Haddad ◽  
...  
Keyword(s):  
Cell Death ◽  
Time Lapse ◽  
Death Process ◽  
Cell Detection ◽  
High Throughput Analysis ◽  
Time Resolved ◽  
Single Cell Detection ◽  
Human Neurons

AbstractCell death is a critical process that occurs normally in health and disease. However, its study is limited due to available technologies that only detect very late stages in the process or specific death mechanisms. Here, we report the development of a family of fluorescent biosensors called genetically encoded death indicators (GEDIs). GEDIs specifically detect an intracellular Ca2+ level that cells achieve early in the cell death process and that marks a stage at which cells are irreversibly committed to die. The time-resolved nature of a GEDI delineates a binary demarcation of cell life and death in real time, reformulating the definition of cell death. We demonstrate that GEDIs acutely and accurately report death of rodent and human neurons in vitro, and show that GEDIs enable an automated imaging platform for single cell detection of neuronal death in vivo in zebrafish larvae. With a quantitative pseudo-ratiometric signal, GEDIs facilitate high-throughput analysis of cell death in time-lapse imaging analysis, providing the necessary resolution and scale to identify early factors leading to cell death in studies of neurodegeneration.

scholarly journals Genetically encoded cell-death indicators (GEDI) to detect an early irreversible commitment to neurodegeneration

2019 ◽  
Author(s):  
Jeremy W. Linsley ◽  
Kevan Shah ◽  
Nicholas Castello ◽  
Michelle Chan ◽  
Dominic Haddad ◽  
...  
Keyword(s):  
Cell Death ◽  
Time Lapse ◽  
Death Process ◽  
Cell Detection ◽  
High Throughput Analysis ◽  
Time Resolved ◽  
Single Cell Detection ◽  
Human Neurons

AbstractCell death is a critical process that occurs normally in health and disease. However, its study is limited due to available technologies that only detect very late stages in the process or specific death mechanisms. Here, we report the development of a new fluorescent biosensor called genetically encoded death indicator (GEDI). GEDI specifically detects an intracellular Ca2+ level that cells achieve early in the cell death process and marks a stage at which cells are irreversibly committed to die. The time-resolved nature of GEDI delineates a binary demarcation of cell life and death in real time, reformulating the definition of cell death. We demonstrate that GEDI acutely and accurately reports death of rodent and human neurons in vitro, and show GEDI enables a novel automated imaging platform for single cell detection of neuronal death in vivo in zebrafish larvae. With a quantitative pseudo-ratiometric signal, GEDI facilitates high-throughput analysis of cell death in time lapse imaging analysis, providing the necessary resolution and scale to identify early factors leading to cell death in studies of neurodegeneration.

scholarly journals Gene-dependent yeast cell death pathway requires AP-3 vesicle trafficking leading to vacuole membrane permeabilization

2021 ◽  
Author(s):  
Zachary D Stolp ◽  
Madhura Kulkarni ◽  
Yining Liu ◽  
Chengzhang Zhu ◽  
Alizay Jalisi ◽  
...  
Keyword(s):  
Cell Death ◽  
Yeast Cell ◽  
Vesicle Trafficking ◽  
Membrane Integrity ◽  
Time Lapse ◽  
Membrane Permeabilization ◽  
Cell Death Pathway ◽  
Sequence Of Events ◽  
A Genome ◽  
Lysosome Membrane

Unicellular eukaryotes are suggested to undergo self-inflicted destruction. However, molecular details are sparse by comparison to the mechanisms of cell death known for human cells and animal models. Here we report a molecular pathway in Saccharomyces cerevisiae leading to vacuole/lysosome membrane permeabilization and cell death. Following exposure to heat-ramp conditions, a model of environmental stress, we observed that yeast cell death occurs over several hours, suggesting an ongoing molecular dying process. A genome-wide screen for death-promoting factors identified all subunits of the AP-3 adaptor complex. AP-3 promotes stress-induced cell death through its Arf1-GTPase-dependent vesicle trafficking function, which is required to transport and install proteins on the vacuole/lysosome membrane, including a death-promoting protein kinase Yck3. Time-lapse microscopy revealed a sequence of events where AP-3-dependent vacuole permeability occurs hours before the loss of plasma membrane integrity. An AP-3-dependent cell death pathway appears to be conserved in the human pathogen Cryptococcus neoformans.

scholarly journals A Study of Late Ventral Body Wall Degeneration in the Embryonic Chick, with Special Reference to the Cell Cycle

2021 ◽  
Author(s):  
◽  
Peter Barwell
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Body Wall ◽  
Morphological Changes ◽  
Cell Loss ◽  
Tissue Growth ◽  
Embryonic Chick ◽  
Cell Death Pathway ◽  
Medial Migration

<p>The cell kinetics and morphological changes during late ventral body wall development of the embryonic chick were studied, particularly midline degeneration and the medial migration of lateral tissues. An histological examination of these events was undertaken, along with autoradiography to determine the duration of the cell cycle, followed by teratological studies involving the prevention of differentiative events in the cell death pathway, using BrDU and Janus B Green as agents. The effects of cell cycle blockade on rates of cell death were also examined, as was the tissues ability to express differentiative features in vitro. Ventral body wall (VBW) cell death was classified as apoptosis, and was involved in two distinct events. Medial migration of lateral tissues began at day 5 of development, with widespread VBW apoptosis being seen by day 6, limited to the original mesoderm of the region. A later precise line of apoptosis (the VBL), involving both ectodermal cells of the midline ectodermal ruffle and the underlying mesodermal cells, was observed at day 7, spreading in a rostral to caudal fashion down the embryo, appearing as the migratory lateral tissues fused in the midline body wall. Increases in the amount of cell death are matched by decreases in the MI, such that at its peak (day 7.5 of development) the cell death rate is sufficiently greater than both the cell proliferation and immigration rates that a state of negative tissue growth ensues. The histological half-life of the apoptotic bodies approximates 3.8 hours. The ability to undergo apoptosis at day 7 is dependent upon a differentiative event around day 4 of incubation, and involves signal mechanisms intrinsic to the VBW tissues. BrDU application was found to inhibit apoptotic differentiation, in contrast to Janus B Green, which had a more generalised teratogenic effect on the region as a whole. Tissue culturing experiments revealed that an ectodermal-mesodermal interaction is important in regulating the extent of mesodermal apoptosis, the ectoderm playing a maintenance role for the mesoderm. Dead cells derive from the cycling cell population, as shown by the occurrence of labelled dead cells after autoradiography, and by the prevention of apoptosis by a cell cycle blockade, and by the production of a semi-synchronised wave of apoptoses after release of this blockade. These cell blockading results further suggest that entry into the apoptotic death program requires cells to be in a particular cell cycle stage, and it seems most likely that the decision to die was made in early G1. Tissue and cell growth rates, cell loss and death rates, cell birth rates and cell immigration rates were all determined for the VBW region throughout the time period studied.</p>

The CD47 Pathway Is Deregulated In Human Immune Thrombocytopenia (ITP).

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3776-3776
Author(s):  
Lucia Catani ◽  
Daria Sollazzo ◽  
Francesca Ricci ◽  
Francesca Palandri ◽  
Nicola Polverelli ◽  
...  
Keyword(s):  
Cell Death ◽  
Immune Thrombocytopenia ◽  
Conflicts Of Interest ◽  
Regulatory Protein ◽  
Immunoglobulin Superfamily ◽  
Phagocytic Capacity ◽  
Platelet Apoptosis ◽  
Cell Death Pathway

Abstract Abstract 3776 The CD47 antigen is a transmembrane glycoprotein ubiquitously expressed on hematopoietic and non-hematopoietic cells. It serves as a receptor for Thrombospondin (TSP) and a ligand for signal regulatory protein-alpha (SIRP-alpha) receptor, acting, respectively, as a regulator of apoptosis and as antagonistic to phagocyte activity. Ligation of CD47 with antibodies, its natural physiological ligand TSP or the specific CD47-binding peptide 41NK induces apoptosis in nucleated blood cells. This apoptosis is characterized by mitochondrial damage and the exposure of phosphatydilserine on the outerleaflet of the plasma membrane. Interaction of SIRP-alpha with CD47 is important also for the regulation of phagocytosis. SIRP-alpha is an immunoglobulin superfamily member and is predominantly expressed in neurons, dendritic cells (DCs) and monocytes/macrophages. Phagocytes engulf foreign cells but not “self” in part because “self” cells express CD47 as a ligand for SIRP-alpha, which inhibits phagocytosis. Thus CD47 functions as a “don't eat me” signal. Based on studies in mice, a novel mechanism of platelet destruction involving the CD47/SIRP-alpha system has been recently suggested in Immune Thrombocytopenia (ITP). Specifically, it has been demonstrated that: 1) platelet homeostasis is regulated by platelet expression of CD47 under normal conditions and in immune thrombocytopenia in a mouse model; 2) interaction between platelet CD47 and macrophage SIRP-alpha is important in regulating normal platelet turnover and FcgammaR-mediated clearance of IgG-sensitized platelets; 3) CD47-deficient platelets have a shortened half-life in the circulation of CD47 wild-type mice and are also more sensitive to Fcgamma receptor-mediated clearance, both in vivo and in vitro. However, the role of CD47 pathway in the pathogenesis of human ITP has not yet been studied. Therefore, the main purpose of the present study was to evaluate whether alterations of this system (platelets/phagocytes) might play a pathogenetic role in human ITP. In particular, we investigated whether in ITP: i) platelets are more susceptible to CD47-induced cell death; ii) expression of CD47 on fresh and in vitro aged platelets is reduced; iii) the platelet phagocytic capacity of CD14-derived DCs and macrophages is differentially modulated in the presence or absence of antibodies against CD47 and SIRP-alpha. Phenotypical and functional analysis of the expression of CD47 on platelets and SIRP-αlpha on CD14-derived/circulating DCs and on CD14-derived macrophages was performed in 32 ITP patients. Patients were newly diagnosed (14 cases) or with persistent (15 cases) or chronic (3 cases) ITP. At the time of the study, patients with persistent or chronic ITP were off therapy by at least two months. None of the patients were splenectomized. The median platelet count at the time of the study was 49×109/L (range 14–98). We found that in healthy subjects CD47 expression increased in in vitro aged platelets and ligation of CD47 with anti-CD47 antibody induced a dose-dependent increase of platelet apoptosis. Immature and mature CD14-derived DCs and circulating myeloid DCs were strongly positive for SIRP-α. Conversely, we demonstrated that in ITP: 1) CD47 expression was unchanged in freshly isolated and in vitro aged platelets; 2) increased platelet apoptosis was not due to the activation of the CD47-induced cell death pathway, which instead was shown to be blocked; 3) the blockage of SIRP-αlpha on immature CD14-derived DCs or CD47 on platelets by specific antibodies failed to modify platelet uptake/phagocytosis of DCs; in contrast, targeting platelet CD47 with specific antibody significantly increases platelet phagocytosis of CD14-derived macrophages. In conclusion, our data demonstrate that in ITP the increased platelet clearance is not due to reduced CD47 expression on platelets. However, platelets from ITP patients are not healthy because 1) apoptosis is increased; 2) platelet apoptosis is independent from CD47 death signal; 3) CD47 expression is not modified by in vitro ageing/apoptosis. In addition, we show that the CD47 pathway plays a role in platelet phagocytosis of macrophages, but not in DCs. We conclude that in ITP patients platelet homeostasis is differentially modulated by the CD47 pathway. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Sindbis Virus-Induced Neuronal Death Is both Necrotic and Apoptotic and Is Ameliorated byN-Methyl-d-Aspartate Receptor Antagonists

2001 ◽  
Vol 75 (15) ◽  
pp. 7114-7121 ◽  
Author(s):  
Jennifer L. Nargi-Aizenman ◽  
Diane E. Griffin
Keyword(s):  
Cell Death ◽  
Cortical Neurons ◽  
Sindbis Virus ◽  
Apoptotic Cell ◽  
Time Lapse ◽  
Apoptotic Cell Death ◽  
Time Lapse Imaging ◽  
Alphavirus Infection

ABSTRACT Virus infection of neurons leads to different outcomes ranging from latent and noncytolytic infection to cell death. Viruses kill neurons directly by inducing either apoptosis or necrosis or indirectly as a result of the host immune response. Sindbis virus (SV) is an alphavirus that induces apoptotic cell death both in vitro and in vivo. However, apoptotic changes are not always evident in neurons induced to die by alphavirus infection. Time lapse imaging revealed that SV-infected primary cortical neurons exhibited both apoptotic and necrotic morphological features and that uninfected neurons in the cultures also died. Antagonists of the N-methyl-d-aspartate (NMDA) subtype of glutamate receptors protected neurons from SV-induced death without affecting virus replication or SV-induced apoptotic cell death. These results provide evidence that SV infection activates neurotoxic pathways that result in aberrant NMDA receptor stimulation and damage to infected and uninfected neurons.

New in vitro insights on a cell death pathway induced by magnolol and honokiol in aristolochic acid tubulotoxicity

2016 ◽  
Vol 87 ◽  
pp. 77-87 ◽  
Author(s):  
Valérian Bunel ◽  
Marie-Hélène Antoine ◽  
Caroline Stévigny ◽  
Joëlle Nortier ◽  
Pierre Duez
Keyword(s):  
Cell Death ◽  
Aristolochic Acid ◽  
Cell Death Pathway ◽  
A Cell

Tetrocarcin-A—induced ER stress mediates apoptosis in B-CLL cells via a Bcl-2—independent pathway

Blood ◽  
2003 ◽  
Vol 101 (11) ◽  
pp. 4561-4568 ◽  
Author(s):  
Gabriele Anether ◽  
Inge Tinhofer ◽  
Monika Senfter ◽  
Richard Greil
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Er Stress ◽  
Clinical Stage ◽  
Response To Therapy ◽  
Lymphocytic Leukemia ◽  
Clinical Markers ◽  
Expression Levels ◽  
Cell Death Pathway

Abstract Tetrocarcin-A (TC-A), an antibiotic agent isolated from actinomycetes, has recently been described to antagonize Bcl-2 functions, thereby sensitizing tumor cells to cell death signals under control of Bcl-2. In this study, we analyzed the direct proapoptotic effect of TC-A in the B-chronic lymphocytic leukemia (B-CLL) model. We focused on the signal cascade triggered by TC-A in B-CLL cells and identified activated mitochondrial as well as endoplasmatic reticulum (ER) stress signals. The expression levels of known effector molecules mediating mitochondrial signaling, such as Bax and Bid, and the antagonistic molecule Bcl-2 did not influence sensitivity of B-CLL cells to TC-A. Furthermore, the molecular chaperone and sensor of ER stress, HSP70, though significantly up-regulated in B-CLL cells undergoing TC-A—triggered apoptosis, was ineffective to exert its anti-apoptotic function described in multiple cell death pathways. Autologous T cells of B-CLL patients were significantly less sensitive to TC-A as were also T cells from healthy donors when compared with their normal B-cell fraction. Furthermore, sensitivity of B-CLL cells to TC-A treatment in vitro was dependent neither on the expression levels of CD38—a prognostic factor for survival of B-CLL patients as well as for their response to therapy—nor on the clinical stage or pretreatment status of patients. From our data showing that TC-A induced a cell death pathway via ER stress preferentially in B cells and that it acted independently of important markers of drug sensitivity and of clinical markers, we conclude that TC-A might represent an attractive candidate drug for further evaluation in preclinical trials.

scholarly journals C1orf109L promote R-loop accumulation induced DNA damage to inhibit cell growth

2019 ◽  
Author(s):  
Dou Peng ◽  
Li Yiqun ◽  
Xie Wanqiu ◽  
Zhang Xiaoqing ◽  
Zhang Dandan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Death ◽  
Cell Growth ◽  
Genome Instability ◽  
Cell Death Pathway ◽  
Unknown Gene ◽  
Lower Expression

AbstractAs a function unknown gene, C1orf109 is lower expression in various cells. Here, we reported that C1orf109L, the longest variant of C1orf109, which interacted with R-loop-regulating proteins to trigger R-loop, a three-stranded nucleic acid structure frequently mediated genome instability, accumulation. C1orf109L induce chronic DNA damage to promote P21 upregulation and strongly inhibits cell growth in vitro and in vivo by arresting the cell cycle in the G2 phase. With camptothecin (CPT), an R-loop activator, treatment, C1orf109L further triggers R-loop accumulation-induced DNA damage and promotes cell death by activating cell-death pathway. Furthermore, CPT treatment increases C1orf109L ubiquitination and turnover, which inhibits cell death and promotes the G0/G1 phase of the cell cycle. Therefore, our data illustrated the mechanisms underlying C1orf109L-related cell growth inhibition and provide feasibility and limitations for C1orf109L as a potential target for cancer therapy.

scholarly journals Caspase-independent programmed cell death triggers Ca2PO4 deposition in an in vitro model of nephrocalcinosis

2018 ◽  
Vol 38 (1) ◽  
Author(s):  
Giovanna Priante ◽  
Federica Quaggio ◽  
Lisa Gianesello ◽  
Monica Ceol ◽  
Rosalba Cristofaro ◽  
...  
Keyword(s):  
Cell Death ◽  
Late Phase ◽  
Annexin V ◽  
Human Kidney ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Death Process ◽  
Osteogenic Medium ◽  
Medullary Nephrocalcinosis ◽  
Calcification Process

Nephrocalcinosis involves the deposition of microscopic crystals in the tubular lumen or interstitium. While the clinical, biochemical, and genetic aspects of the diseases causing nephrocalcinosis have been elucidated, little is known about the cellular events in this calcification process. We previously reported a phenomenon involving the spontaneous formation of Ca2PO4 nodules in primary papillary renal cells from a patient with medullary nephrocalcinosis harboring a rare glial cell-derived neurotrophic factor (GDNF) gene variant. We also demonstrated that cultivating GDNF-silenced human kidney-2 (HK-2) cells in osteogenic conditions for 15 days triggered Ca2PO4 deposits. Given the reportedly close relationship between cell death and pathological calcification, aim of the present study was to investigate whether apoptosis is involved in the calcification of GDNF-silenced HK-2 cells under osteogenic conditions. Silenced and control cells were cultured in standard and osteogenic medium for 1, 5, and 15 days, and any Ca2PO4 deposition was identified by means of von Kossa staining and environmental SEM (ESEM) analyses. Based on the results of annexin V and propidium iodide (PI) analysis, and terminal deoxynucleotidyl transferase dUTP-biotin nick end labeling (TUNEL) assay, the silenced cells in the osteogenic medium showed a significant increase in the percentage of cells in the late phase of apoptosis and an increased Ca2PO4 deposition at 15 days. The results of quantitative real-time PCR (qRT-PCR) of BAX and BCL2, and in-cell Western analysis of caspases indicated that the cell death process was independent of caspase-3, -6, -7, and -9 activation, however. Using this model, we provide evidence of caspase-independent cell death triggering the calcification process in GDNF-silenced HK-2 cells.

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