scholarly journals The energy requirements of ion homeostasis determine the lifespan of starving bacteria

2021 ◽  
Author(s):  
Severin Josef Schink ◽  
Mark Polk ◽  
Edward Athaide ◽  
Avik Mukherjee ◽  
Constantin Ammar ◽  
...  
Keyword(s):  
Cell Death ◽  
Nutrient Recycling ◽  
Ion Homeostasis ◽  
Inorganic Ions ◽  
Time Lapse ◽  
Growth Conditions ◽  
Medium Composition ◽  
Death Process ◽  
Primary Determinant ◽  
Starvation Survival

The majority of microbes on earth, whether they live in the ocean, the soil or in animals, are not growing, but instead struggling to survive starvation. Some genes and environmental conditions affecting starvation survival have been identified, but despite almost a century of study, we do not know which processes lead to irreversible loss of viability, which maintenance processes counteract them and how lifespan is determined from the balance of these opposing processes. Here, we used time-lapse microscopy to capture and characterize the cell death process of E. coli during carbon starvation for the first time. We found that a lack of nutrients results in the collapse of ion homeostasis, triggering a positive-feedback cascade of osmotic swelling and membrane permeabilization that ultimately results in lysis. Based on these findings, we hypothesized that ion transport is the major energetic requirement for starving cells and the primary determinant of the timing of lysis. We therefore developed a mathematical model that integrates ion homeostasis and cannibalistic nutrient recycling from perished cells to predict lifespan changes under diverse conditions, such as changes of cell size, medium composition, and prior growth conditions. Guided by model predictions, we found that cell death during starvation could be dramatically slowed by replacing inorganic ions from the medium with a non-permeating osmoprotectant, removing the cost of ion homeostasis and preventing lysis. Our quantitative and predictive model explains how survival kinetics are determined in starvation and elucidates the mechanistic underpinnings of starvation survival.

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 A unique mode of keratinocyte death requires intracellular acidification

2021 ◽  
Vol 118 (17) ◽  
pp. e2020722118
Author(s):  
Takeshi Matsui ◽  
Nanako Kadono-Maekubo ◽  
Yoshiro Suzuki ◽  
Yuki Furuichi ◽  
Keiichiro Shiraga ◽  
...  
Keyword(s):  
Cell Death ◽  
Molecular Mechanisms ◽  
Transient Receptor Potential ◽  
Nuclear Dna ◽  
Receptor Potential ◽  
Time Lapse ◽  
Intravital Imaging ◽  
Death Process ◽  
Intracellular Acidification

The stratum corneum (SC), the outermost epidermal layer, consists of nonviable anuclear keratinocytes, called corneocytes, which function as a protective barrier. The exact modes of cell death executed by keratinocytes of the upper stratum granulosum (SG1 cells) remain largely unknown. Here, using intravital imaging combined with intracellular Ca2+- and pH-responsive fluorescent probes, we aimed to dissect the SG1 death process in vivo. We found that SG1 cell death was preceded by prolonged (∼60 min) Ca2+ elevation and rapid induction of intracellular acidification. Once such intracellular ionic changes were initiated, they became sustained, irreversibly committing the SG1 cells to corneocyte conversion. Time-lapse imaging of isolated murine SG1 cells revealed that intracellular acidification was essential for the degradation of keratohyalin granules and nuclear DNA, phenomena specific to SC corneocyte formation. Furthermore, intravital imaging showed that the number of SG1 cells exhibiting Ca2+ elevation and the timing of intracellular acidification were both tightly regulated by the transient receptor potential cation channel V3. The functional activity of this protein was confirmed in isolated SG1 cells using whole-cell patch-clamp analysis. These findings provide a theoretical framework for improved understanding of the unique molecular mechanisms underlying keratinocyte-specific death mode, namely corneoptosis.

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 Antagonizing the spindle assembly checkpoint silencing enhances paclitaxel and Navitoclax-mediated apoptosis with distinct mechanistic

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana C. Henriques ◽  
Patrícia M. A. Silva ◽  
Bruno Sarmento ◽  
Hassan Bousbaa
Keyword(s):  
Cell Death ◽  
Cancer Cells ◽  
Cell Fate ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Time Lapse ◽  
Antimitotic Drugs ◽  
Mitotic Slippage ◽  
Mitotic Death ◽  
Chronic Activation

AbstractAntimitotic drugs arrest cells in mitosis through chronic activation of the spindle assembly checkpoint (SAC), leading to cell death. However, drug-treated cancer cells can escape death by undergoing mitotic slippage, due to premature mitotic exit. Therefore, overcoming slippage issue is a promising chemotherapeutic strategy to improve the effectiveness of antimitotics. Here, we antagonized SAC silencing by knocking down the MAD2-binding protein p31comet, to delay mitotic slippage, and tracked cancer cells treated with the antimitotic drug paclitaxel, over 3 days live-cell time-lapse analysis. We found that in the absence of p31comet, the duration of mitotic block was increased in cells challenged with nanomolar concentrations of paclitaxel, leading to an additive effects in terms of cell death which was predominantly anticipated during the first mitosis. As accumulation of an apoptotic signal was suggested to prevent mitotic slippage, when we challenged p31comet-depleted mitotic-arrested cells with the apoptosis potentiator Navitoclax (previously called ABT-263), cell fate was shifted to accelerated post-mitotic death. We conclude that inhibition of SAC silencing is critical for enhancing the lethality of antimitotic drugs as well as that of therapeutic apoptosis-inducing small molecules, with distinct mechanisms. The study highlights the potential of p31comet as a target for antimitotic therapies.

scholarly journals Correction: PML induces a novel caspase-independent cell death process

10.1038/8706 ◽  
1999 ◽  
Vol 22 (1) ◽  
pp. 115-115 ◽  
Author(s):  
Fredérique Quignon
Keyword(s):  
Cell Death ◽  
Death Process ◽  
Cell Death Process

scholarly journals Analysis of programmed cell death in mouse fetal oocytes

Reproduction ◽  
2007 ◽  
Vol 134 (2) ◽  
pp. 241-252 ◽  
Author(s):  
A M Lobascio ◽  
F G Klinger ◽  
M L Scaldaferri ◽  
D Farini ◽  
M De Felici
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Specific Inhibitor ◽  
Annexin V ◽  
Death Process ◽  
Parp Cleavage ◽  
Tunel Staining ◽  
Calpain Inhibitor ◽  
Dna Ladder ◽  
Caspase 2

We report a short-term culture system that allowsto define novel characteristic of programmed cell death (PCD) in fetal oocytes and to underscore newaspects of this process. Mouse fetal oocytes culturedin conditions allowingmeiotic prophase I progression underwent apoptotic degeneration waves as revealed by TUNEL staining. TEM observations revealed recurrent atypical apoptotic morphologies characterized by the absence of chromatin margination and nuclear fragmentation; oocytes with autophagic and necrotic features were also observed. Further characterization of oocyte death evidenced DNA ladder, Annexin V binding, PARP cleavage, and usually caspase activation (namely caspase-2). In the aim to modulate the oocyte death process, we found that the addition to the culture medium of the pancaspase inhibitors Z-VAD orcaspase-2-specific inhibitor Z-VDVAD resulted in a partial and transient prevention of this process. Oocyte death was significantly reduced by the antioxidant agent NAC and partly prevented by KL and IGF-I growth factors. Finally, oocyte apoptosis was reduced by calpain inhibitor I and increased by rapamycin after prolonged culture.These results support the notion that fetal oocytes undergo degeneration mostly by apoptosis. This process is, however, often morphologically atypical and encompasses other forms of cell death including caspase-independent apoptosis and autophagia. The observation that oocyte death occurs mainly at certain stages of meiosis and can only be attenuated by typical anti-apoptotic treatments favors the notion that it is controlled at least in part by stage-specific oocyte-autonomous meiotic checkpoints and when activated is little amenable to inhibition being the oocyte able to switch back and forth among different death pathways.

scholarly journals Screening for Modulators of Spermine Tolerance Identifies Sky1, the SR Protein Kinase of Saccharomyces cerevisiae, as a Regulator of Polyamine Transport and Ion Homeostasis

2001 ◽  
Vol 21 (1) ◽  
pp. 175-184 ◽  
Author(s):  
Omri Erez ◽  
Chaim Kahana
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Osmotic Shock ◽  
Ion Homeostasis ◽  
Inorganic Ions ◽  
Yeast Cells ◽  
Wild Type ◽  
Sr Protein ◽  
Polyamine Transport ◽  
Increased Sensitivity

ABSTRACT Although most cells are capable of transporting polyamines, the mechanism that regulates polyamine transport in eukaryotes is still largely unknown. Using a genetic screen for clones capable of restoring spermine sensitivity to spermine-tolerant mutants ofSaccharomyces cerevisiae, we have demonstrated that Sky1p, a recently identified SR protein kinase, is a key regulator of polyamine transport. Yeast cells deleted for SKY1 developed tolerance to toxic levels of spermine, while overexpression of Sky1p in wild-type cells increased their sensitivity to spermine. Expression of the wild-type Sky1p but not of a catalytically inactive mutant restored sensitivity to spermine. SKY1 disruption results in dramatically reduced uptake of spermine, spermidine, and putrescine. In addition to spermine tolerance, sky1Δ cells exhibit increased tolerance to lithium and sodium ions but somewhat increased sensitivity to osmotic shock. The observed halotolerance suggests potential regulatory interaction between the transport of polyamines and inorganic ions, as suggested in the case of the Ptk2p, a recently described regulator of polyamine transport. We demonstrate that these two kinases act in two different signaling pathways. While deletion or overexpression of SKY1 did not significantly affect Pma1p activity, the ability of overexpressed Sky1p, Ptk1p, and Ptk2p to increase sensitivity to LiCl depends on the integrity ofPPZ1 but not of ENA1.

scholarly journals Production of Prodiginines Is Part of a Programmed Cell Death Process in Streptomyces coelicolor

2018 ◽  
Vol 9 ◽  
Author(s):  
Elodie Tenconi ◽  
Matthew F. Traxler ◽  
Charline Hoebreck ◽  
Gilles P. van Wezel ◽  
Sébastien Rigali
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Streptomyces Coelicolor ◽  
Death Process ◽  
Cell Death Process
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