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Hypoxia, Free Radicals, and Reperfusion Injury Following Cold Storage and Reperfusion of Livers for Transplantation
Published in John J. Lemasters, Constance Oliver, Cell Biology of Trauma, 2020
Ronald G. Thurman, Wenshi Gao, Henry D. Connor, Sigrid Bachmann, Robert T. Currin, Ronald P. Mason, John J. Lemasters
Frequently, cell killing by A23187, the calcium ionophore, is cited as an example of Ca2+-dependent cell killing.72 In hepatocytes, fructose alone does not protect against lethal cell injury caused by Br-A23187, a nonfluorescent analog of A23187; however, fructose in combination with oligomycin does offer protection.57 A23187 is a potent uncoupler of mitochondrial oxidative phosphorylation.73 Oligomycin, a specific inhibitor of the uncoupler-stimulated mitochondrial ATPase, is cytotoxic by itself. Protection by the combination of fructose and oligomycin suggests that cell killing by A23187 is mediated by mitochondrial uncoupling and consequent cellular ATP depletion, rather than by Ca2+ entry into hepatocytes per se. Fructose also protects against CCCP, a classical mitochondrial uncoupler, only when oligomycin is present.57,60
The Effect of Activated Inflammatory Cells on Colonic Smooth Muscle Contraction
Published in William J. Snape, Stephen M. Collins, Effects of Immune Cells and Inflammation on Smooth Muscle and Enteric Nerves, 2020
Lin Chang, Martha Hierro, Louise E. LeDuc, Fergus Shanahan, Fabio Cominelli, William J. Snape
Colonic smooth muscle tension decreased slightly after exposure with the supernatants of unstimulated neutrophils and calcium ionophore-stimulated neutrophils when compared to incubation with Krebs solution alone (Table 1). There was no significant difference between the amount of inhibition with or without the presence of calcium ionophore. Addition of calcium ionophore alone to the muscle bath did not alter smooth muscle tension.
The Role of Procoagulant Activity in Fulminant Viral Hepatitis
Published in Gary A. Levy, Edward H. Cole, Procoagulant Activity in Health and Disease, 2019
Stephen W. Chung, Chao-Ying Li, Julian Leibowitz, Gary A. Levy
The mechanism of induction of TF has been explored by several investigators and is controversial. Lyberg and Prydz have demonstrated that induction of TF by human monocytes is a protein kinase C (PKC)-dependent event since TF could be induced by phorbol esters.73 Furthermore, despite the findings that TF induction was calcium dependent and that the calcium ionophore A23187 was capable of inducing TF,74,75 no detectable changes in cytosolic calcium were associated with TF induction.74 In contrast, Kucey et al. suggest that calcium ionophores and phorbol esters do not result in TF expression.76 The differences in these results may be related to the cell populations studied, species of origin (human or rodent), and/or the incubation and culture conditions.
Conflicting actions of 4-vinylcatechol in rat lymphocytes under oxidative stress induced by hydrogen peroxide
Published in Drug and Chemical Toxicology, 2020
Takumi Kishida, Yurie Funakoshi, Yuya Fukuyama, Sari Honda, Toshiya Masuda, Yasuo Oyama
300 µM H2O2 was used to give oxidative stress to the cells because of following observation. The incubation time with 100–300 µM H2O2 to induce cell death was 3–4 h. The cell lethality was 20–40% after 4 h incubation with 300 µM H2O2 although the value varied from preparation to preparation. However, the incubation with 300 µM H2O2 for 1 h or shorter did not increase the cell lethality. A23187, a calcium ionophore, at 100 nM for intracellular Ca2+ overload induced cell death in 20–40% of rat thymocytes within 3–4 h after the application while it was not the case under Ca2+-free conditions (Nishizaki et al.2003, Sakanashi et al.2008). A23187 and 4VC were simultaneously added to the cell suspension.
Assisted oocyte activation with calcium ionophore 44 hours after intracytoplasmic sperm injection resulting in successful pregnancy
Published in Gynecological Endocrinology, 2020
Haitao Xi, Yanghua Fu, Chang Liu, Xiaosheng Lu, Liucai Sui, Yulu Chen, Junzhao Zhao
During in vitro fertilization, both sperm and ovum need to undergo the process of capacitation. Sperm capacitation could be operated by using A23187 calcium solution or heparin. Calcium ionophore A23187 is a kind of mobile ionophore, which could transport bivalent cation such as calcium ion or magnesium ion into the cells and take two hydrogen ions outside the cells simultaneously. When A23187 is added to the culture medium containing calcium ion, the calcium ion could enter into the cytoplasm quickly. Thus, A23187 is widely used in cell biological research to increase the concentration of free calcium in the cytoplasm.
The role of SCAMP5 in central nervous system diseases
Published in Neurological Research, 2022
Ye Chen, Jiali Fan, Dongqiong Xiao, Xihong Li
However, the role of SCAMP5 has only been recognized in recent years. Using human dendritic cell cDNA or SCAMP5 plasmid as a template, an expression vector was transfected into HeLa cells for analysis. Through methods such as subcellular separation and membrane vesicle immune separation, SCAMP5 was found to be triggered by ionomycin to rapidly translocate from the Golgi apparatus to the plasma membrane along the classical exocytosis pathway and promote cytokine exocytosis [15]. Cytokines can be classified into signal peptide-containing cytokines and signal peptide-free cytokines. The former includes RANTES/CCL5 and IL-6, and the latter includes IL-1β and fibroblast growth factor (FGF). Cytokines containing signal peptides are secreted through the classical pathway, that is, from the endoplasmic reticulum to the Golgi apparatus and then to the plasma membrane [24]. Cells without signal peptides rely on nonclassical pathways [25]. As a model of exocytosis, SCAMP5 can promote the exocytosis of signal peptides containing cytokines but does not have this effect on cytokines without signal peptides. Ionomycin is a calcium ionophore that can increase the level of intracellular calcium ions and then promote membrane target docking and fusion. Studies have shown that upon ionomycin stimulation, SCAMP5 can promote the release of cytokines from macrophages, and SCAMP5 together with CCL5can be quickly transported to the plasma membrane, confirming that SCAMP5 is involved in the classical secretory transport pathway [15]. Through its C-terminal tail, SCAMP5 can bind to Synaptotagmin 1 (SYT1). SYT1 is a calcium ion-bound vesicle membrane protein that acts as a calcium ion receptor during exocytosis [26]. The interaction between SCAMP5 and SYT1 may be a result of SCAMP5 participation in calcium-triggered exocytosis.