Resting Ca2+ influx does not contribute to anoxia-induced cell death in adult rat cardiac myocytes

2009 ◽  
Vol 87 (5) ◽  
pp. 360-370
Author(s):  
Meghan R. Mont ◽  
C. George Carlson ◽  
Timothy P. Geisbuhler

Calcium has been proposed as a primary influence on cell death during ischemic episodes in myocardial cells. One component of calcium entry into a cell is resting calcium influx. This basal movement of calcium is blocked by 100 µmol/L gadolinium chloride (GdCl3) in cardiac myocytes. Therefore, GdCl3 should be cardioprotective under anoxic conditions. To test this, cardiac myocytes isolated from adult male rats were subjected to anoxia (100% N2) in the presence or absence of 100 µmol/L GdCl3 in one of 2 ways. In the first method, cells were suspended in media and rendered anoxic for 0, 30, and 60 min, after which cell morphology and viability were scored. After 60 min of anoxia, rod-shaped cells accounted for 46% ± 4% of total cells (viability 81%); 10 min of reoxygenation markedly reduced rod-shaped cells to 27% (viability 72%). GdCl3 in the medium did not protect the cells (anoxic rods 49%, reoxygenated rods 30%, viability 77%). In the second method, cells were attached to a laminin substrate, rendered anoxic, and then videotaped for up to 6 h. In this system, cells maintained their shape for some time after the onset of anoxia, and then began to ‘die’ (i.e., to take on either a rigor form or hypercontracted form) at a measurable rate. Time to onset of ‘death’ (t0), time to 50% and 100% ‘death’ (t50 and t100), and rate of ‘death’ were used to measure anoxic damage. Without GdCl3, cells on average began to die 115 ± 32 min after the onset of anoxia (t0); they died at an average rate of 0.046 cells/min. t50 was achieved in 149 ± 42 min, t100 in 183 ± 54 min. Addition of 100 µmol/L GdCl3 did not affect any of these parameters. We concluded that GdCl3 was not cardioprotective for anoxic myocytes and that cell damage generated by anoxia could not be attributed to resting calcium influx.


1999 ◽  
Vol 277 (3) ◽  
pp. H1189-H1199 ◽  
Author(s):  
David J. Pinsky ◽  
Walif Aji ◽  
Matthias Szabolcs ◽  
Eleni S. Athan ◽  
Youping Liu ◽  
...  

Excessive nitric oxide (NO) production within the heart is implicated in the pathogenesis of myocyte death, but the mechanism whereby NO kills cardiac myocytes is not known. To determine whether NO may trigger programmed cell death (apoptosis) of adult rat ventricular myocytes in culture, the NO donor S-nitroso- N-acetylpenicillamine (SNAP) was shown to kill purified cardiac myocytes in a dose-dependent fashion. In situ analysis of ventricular myocytes plated on chamber slides using nick-end labeling of DNA demonstrated that SNAP induces cardiac myocyte apoptosis, which was confirmed by the identification of oligonucleosomal DNA fragmentation on agarose gel electrophoresis. Similarly, treatment of cardiac myocytes with cytokines that induce inducible NO synthase was shown to cause an NO-dependent induction of apoptosis. Addition of reduced hemoglobin to scavenge NO liberated by SNAP extinguished both the increase in percentage of apoptotic cells and the appearance of DNA ladders. Treatment with SNAP (but not with N-acetylpenicillamine or SNAP + hemoglobin) not only induced apoptosis but resulted in a marked increase in p53 expression in cardiac myocytes detected by Western blotting and immunohistochemistry. These data indicate that NO has the capacity to kill cardiac myocytes by triggering apoptosis and suggest the involvement of p53 in this process.



2016 ◽  
Vol 01 (01) ◽  

Objective: When cells are incubated with various particles in phagocytosis experiment, the cells include two populations. One is the population which engulfed the particles; the other is the population which did not engulf them. We separated both populations by use of a cell sorter and evaluated the cell death of the population which engulfed the particles to clarify the cytotoxic effect by the phagocytized particles in this study. Methods and Results: Thioglycollate-elicited peritoneal macrophages engulfed 100 nm and 1000 nm of non-crystalline silica and polystyrene particles. Phagocytosis of these particles increased depending on the quantity of added particles. The treatment of the cells with 1000 nm silica particles induced release of lactate dehydrogenase (LDH) and production of interleukin-1β (IL-1β). On the other hand, 100 nm silica particles did not increase the LDH release and the IL-1β production. Polystyrene particles also did not have cytotoxic and inflammatory effects. To elucidate the relation of phagocytosis and cytotoxicity, the cells incubated with 1000 nm silica particles were divided into non-phagocytic and phagocytic population by use of a cell sorter. As most of dead cells stained by propidium iodide were observed in the phagocytic cells population, the phagocytosis of 1000 nm silica particle was associated with cell damage directly. The silica-induced cell death was not accompanied with the externalization of phosphatidylserine in the plasma membrane. Conclusions: These results indicated the following things: (1) The engulfment of certain size of the silica particles induced cell death in the macrophages, (2) The cell death was not typical apoptosis and (3) The cell death was accompanied with the activation of inflammasome.



2019 ◽  
pp. S375-S384 ◽  
Author(s):  
S. Binder ◽  
B Hosikova ◽  
Z. Mala ◽  
L. Zarska ◽  
H. Kolarova

Photodynamic therapy (PDT) uses photosensitive substance to provoke a cytotoxic reaction causing a cell damage or cell death. The substances, photosensitizers, are usually derivates of porphyrine or phtalocyanine. Photosensitizers must be activated by light in order to produce reactive oxygen species, mainly singlet oxygen. Sonodynamic therapy (SDT) utilizes ultrasound to enhance a cytotoxic effects of compounds called sonosensitizers. In this study we investigated photodynamic and sonodynamic effect of chloraluminium phtalocyanine disulfonate (ClAlPcS(2)) on HeLa cells. DNA damage, cell viability and reactive oxygen species (ROS) production were assessed to find whether the combination of PDT and SDT inflicts HeLa cells more than PDT alone. We found that the combined therapy increases DNA fragmentation, enhances ROS production and decreases cell survival. Our results indicate that ClAlPcS(2) can act as a sonosentitiser and combined with PDT causes more irreversible changes to the cells resulting in cell death than PDT alone.



2002 ◽  
Vol 72 (3) ◽  
pp. 147-153 ◽  
Author(s):  
Kei-Ichi Hirai ◽  
Jie-Hong Pan ◽  
Ying-Bo Shui ◽  
Eriko Simamura ◽  
Hiroki Shimada ◽  
...  

The possible protection of cultured human cells from acute dioxin injury by antioxidants was investigated. The most potent dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), caused vacuolization of the smooth endoplasmic reticulum and Golgi apparatus in cultured human conjunctival epithelial cells and cervical cancer cells. Subsequent nuclear damage included a deep irregular indentation resulting in cell death. A dosage of 30–40 ng/mL TCDD induced maximal intracellular production of H2O2 at 30 minutes and led to severe cell death (0–31% survival) at two hours. A dose of 1.7 mM alpha-tocopherol or 1 mM L-dehydroascorbic acid significantly protected human cells against acute TCDD injuries (78–97% survivals), but vitamin C did not provide this protection. These results indicate that accidental exposure to fatal doses of TCDD causes cytoplasmic free radical production within the smooth endoplasmic reticular systems, resulting in severe cytotoxicity, and that vitamin E and dehydroascorbic acid can protect against TCDD-induced cell damage.



2003 ◽  
Vol 23 (5-6) ◽  
pp. 421-440 ◽  
Author(s):  
Ann-Muriel Steff ◽  
Marylene Fortin ◽  
Fabianne Philippoussis ◽  
Sylvie Lesage ◽  
Chantal Arguin ◽  
...  


2019 ◽  
Vol 16 (1) ◽  
pp. 3-11
Author(s):  
Luisa Halbe ◽  
Abdelhaq Rami

Introduction: Endoplasmic reticulum (ER) stress induced the mobilization of two protein breakdown routes, the proteasomal- and autophagy-associated degradation. During ERassociated degradation, unfolded ER proteins are translocated to the cytosol where they are cleaved by the proteasome. When the accumulation of misfolded or unfolded proteins excels the ER capacity, autophagy can be activated in order to undertake the degradative machinery and to attenuate the ER stress. Autophagy is a mechanism by which macromolecules and defective organelles are included in autophagosomes and delivered to lysosomes for degradation and recycling of bioenergetics substrate. Materials and Methods: Autophagy upon ER stress serves initially as a protective mechanism, however when the stress is more pronounced the autophagic response will trigger cell death. Because autophagy could function as a double edged sword in cell viability, we examined the effects autophagy modulation on ER stress-induced cell death in HT22 murine hippocampal neuronal cells. We investigated the effects of both autophagy-inhibition by 3-methyladenine (3-MA) and autophagy-activation by trehalose on ER-stress induced damage in hippocampal HT22 neurons. We evaluated the expression of ER stress- and autophagy-sensors as well as the neuronal viability. Results and Conclusion: Based on our findings, we conclude that under ER-stress conditions, inhibition of autophagy exacerbates cell damage and induction of autophagy by trehalose failed to be neuroprotective.



2021 ◽  
pp. 074823372110226
Author(s):  
Gholamali Jelodar ◽  
Mansour Azimzadeh ◽  
Fatemeh Radmard ◽  
Narges Darvishhoo

Exposure to mobile phone radiation causes deleterious health effects on biological systems. The objects of this study were to investigate the effect of 900-MHz radiofrequency waves (RFW) emitted from base transceiver station antenna on intrapancreatic homocysteine (Hcy), tumor necrosis factor-α (TNF-α), and nerve growth factor (NGF) as predisposing factors involved in pancreatic beta cell damage. Thirty male rats (Sprague-Dawley, 200 ± 10 g) were randomly divided into the control (without any exposure) and exposed groups: short time (2 h/day), long time (4 h/day), and exposed to 900-MHz RFW for 30 consecutive days. On the last days of the experiment, animals were killed and pancreas tissue was dissected out for evaluation of serotonin, Hcy, TNF-α, and NGF. There was a significant decrease in the serotonin and NGF levels in the pancreatic tissue of exposed groups compared to the control group ( p < 0.05). Also, the levels of serotonin and NGF in the long-time exposure were significantly lower than the short-time exposure ( p < 0.05). However, levels of Hcy and TNF-α were significantly increased in the pancreas of exposed groups compared to the control groups ( p < 0.05). Exposure to 900-MHz RFW decreased pancreatic NGF and serotonin levels and increased the proinflammatory markers (Hcy and TNF-α), which can be a predisposing factor for type 2 diabetes.



Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1490
Author(s):  
Osama M. Elzamzamy ◽  
Brandon E. Johnson ◽  
Wei-Chih Chen ◽  
Gangqing Hu ◽  
Reinhold Penner ◽  
...  

Multiple myeloma (MM) is a currently incurable hematologic cancer. Patients that initially respond to therapeutic intervention eventually relapse with drug resistant disease. Thus, novel treatment strategies are critically needed to improve patient outcomes. Our group has developed a novel cyclic peptide referred to as MTI-101 for the treatment of MM. We previously reported that acquired resistance to HYD-1, the linear form of MTI-101, correlated with the repression of genes involved in store operated Ca2+ entry (SOCE): PLCβ, SERCA, ITPR3, and TRPC1 expression. In this study, we sought to determine the role of TRPC1 heteromers in mediating MTI-101 induced cationic flux. Our data indicate that, consistent with the activation of TRPC heteromers, MTI-101 treatment induced Ca2+ and Na+ influx. However, replacing extracellular Na+ with NMDG did not reduce MTI-101-induced cell death. In contrast, decreasing extracellular Ca2+ reduced both MTI-101-induced Ca2+ influx as well as cell death. The causative role of TRPC heteromers was established by suppressing STIM1, TRPC1, TRPC4, or TRPC5 function both pharmacologically and by siRNA, resulting in a reduction in MTI-101-induced Ca2+ influx. Mechanistically, MTI-101 treatment induces trafficking of TRPC1 to the membrane and co-immunoprecipitation studies indicate that MTI-101 treatment induces a TRPC1-STIM1 complex. Moreover, treatment with calpeptin inhibited MTI-101-induced Ca2+ influx and cell death, indicating a role of calpain in the mechanism of MTI-101-induced cytotoxicity. Finally, components of the SOCE pathway were found to be poor prognostic indicators among MM patients, suggesting that this pathway is attractive for the treatment of MM.



1995 ◽  
Vol 4 (1) ◽  
pp. 5-15 ◽  
Author(s):  
C. Haanen ◽  
I. Vermes

During the last few decades it has been recognized that cell death is not the consequence of accidental injury, but is the expression of a cell suicide programme. Kerr et al. (1972) introduced the term apoptosis. This form of cell death is under the influence of hormones, growth factors and cytokines, which depending upon the receptors present on the target cells, may activate a genetically controlled cell elimination process. During apoptosis the cell membrane remains intact and the cell breaks into apoptotic bodies, which are phagocytosed. Apoptosis, in contrast to necrosis, is not harmful to the host and does not induce any inflammatory reaction. The principal event that leads to inflammatory disease is cell damage, induced by chemical/physical injury, anoxia or starvation. Cell damage means leakage of cell contents into the adjacent tissues, resulting in the capillary transmigration of granulocytes to the injured tissue. The accumulation of neutrophils and release of enzymes and oxygen radicals enhances the inflammatory reaction. Until now there has been little research into the factors controlling the accumulation and the tissue load of granulocytes and their histotoxic products in inflammatory processes. Neutrophil apoptosis may represent an important event in the control of intlamtnation. It has been assumed that granulocytes disintegrate to apoptotic bodies before their fragments are removed by local macrophages. Removal of neutrophils from the inflammatory site without release of granule contents is of paramount importance for cessation of inflammation. In conclusion, apoptotic cell death plays an important role in inflammatory processes and in the resolution of inflammatory reactions. The facts known at present should stimulate further research into the role of neutrophil, eosinophil and macrophage apoptosis in inflammatory diseases.



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