scholarly journals Effects of diethyldithiocarbamate and endogenous polyamine content on cellular responses to hydrogen peroxide cytotoxicity

1989 ◽  
Vol 260 (2) ◽  
pp. 487-490 ◽  
Author(s):  
P M Harari ◽  
M E Tome ◽  
D J M Fuller ◽  
S W Carper ◽  
E W Gerner
Keyword(s):  
Heat Shock ◽  
Cellular Response ◽  
Chinese Hamster ◽  
Resting Cells ◽  
H2o2 Treatment ◽  
Polyamine Content ◽  
Response To Stress ◽  
Stress Dependent ◽  
Common Facet ◽  
Stimulation Of

In exponential-phase Chinese-hamster cells, 0.1 mM-diethyldithiocarbamate (DDC) afforded greater than 1 log survival protection to cultures treated before and during exposure to 1 mM-H2O2. Both DDC and H2O2 treatment stimulated the activity of ornithine decarboxylase (ODC), the first enzyme in polyamine synthesis, within 4 h of exposure. DDC, and to a lesser degree H2O2, also stimulated the activity of spermidine N1-acetyltransferase (SAT), the rate-limiting enzyme in polyamine catabolism. The increase in SAT activity, after exposure to DDC or another stress (heat shock), was inhibited in cells depleted of putrescine and spermidine by alpha-difluoromethylornithine (DFMO), the enzyme-activated suicide inhibitor of ODC. Pretreatment with DFMO or heat shock also induced resistance to H2O2 cytotoxicity. Since SAT activity is low in resting cells, yet stimulation of enzyme activity depends on endogenous spermidine pools, these results suggest that the expression of SAT activity occurs by a mechanism involving a stress-dependent displacement of spermidine into a new intracellular compartment. The stimulation of ODC and SAT activities does not appear to be a necessary component of the mechanism by which DDC protects cells from H2O2 cytotoxicity, although spermidine displacement may be a common facet of the cellular response to stress.

scholarly journals Regulation of Glucocorticoid Receptor Activity by a Stress Responsive Transcriptional Cofactor

2011 ◽  
Vol 25 (1) ◽  
pp. 58-71 ◽  
Author(s):  
Laura Davies ◽  
Elissavet Paraskevopoulou ◽  
Malihah Sadeq ◽  
Christiana Symeou ◽  
Constantia Pantelidou ◽  
...  
Keyword(s):  
Dna Damage ◽  
Heat Shock ◽  
Glucocorticoid Receptor ◽  
Cellular Response ◽  
Transcriptional Activity ◽  
Hormone Receptors ◽  
Proteasome Inhibition ◽  
Tetratricopeptide Repeat ◽  
Dependent Manner ◽  
Stress Dependent

The activity of the glucocorticoid receptor (GR) is modulated by posttranslational modifications, protein stability, and cofactor recruitment. In this report, we investigated the role of the stress-responsive activator of p300/tetratricopeptide repeat domain 5 (TTC5), in the regulation of the GR. TTC5 is a member of the TTC family of proteins and has previously been shown to participate in the cellular response to DNA damage and heat shock. Here, we demonstrate that TTC5 is an important cofactor for the nuclear hormone receptors GR and estrogen receptor. GR and TTC5 interact through multiple tetratricopeptide repeat and LXXLL motifs. TTC5 stabilizes GR and increases its half-life, through a proteasome-dependent process and by inhibiting the actions of the ubiquitin ligase murine double minute 2. Cellular stress, including DNA damage, proteasome inhibition, and heat shock, modulates the interaction pattern of GR/TTC5, thereby altering GR stability and transcriptional activity. Furthermore, GR transcriptional activity is regulated by TTC5 in both a positive and negative fashion under DNA damage conditions in a target gene-specific way. In this report we provide evidence supporting the notion that TTC5 is a novel cofactor regulating GR function in a stress-dependent manner.

scholarly journals Cell type-dependent control of p53 transcription and enhancer activity by p63

2018 ◽  
Author(s):  
Gizem Karsli Uzunbas ◽  
Faraz Ahmed ◽  
Morgan A. Sammons
Keyword(s):  
Transcriptional Activation ◽  
Cellular Response ◽  
Cell Types ◽  
Regulatory Elements ◽  
Cell Type ◽  
P53 Family ◽  
Enhancer Activity ◽  
Response To Stress ◽  
Cell Type Specific ◽  
Stress Dependent

ABSTRACTTranscriptional activation by p53 provides powerful, organism-wide tumor suppression. In this work, we demonstrate that the p53-induced transcriptome varies based on cell type, reflects cell type-specific activities, and is considerably more broad than previously anticipated. This behavior is strongly influenced by p53 engagement with differentially active cell type-specific enhancers and promoters. In epithelial cell types, p53 activity is dependent on the p53 family member p63, which displays widespread enhancer binding. Notably, we demonstrate that p63 is required for epithelial enhancer identity including enhancers used by p53 during stress-dependent signaling. Loss of p63, but not p53, leads to site-specific depletion of enhancer-associated chromatin modifications, suggesting that p63 functions as an enhancer maintenance factor in epithelial cells. Additionally, a subset of epithelial-specific enhancers is dependent on the activity of p63 providing a direct link between lineage determination and enhancer structure. These data suggest a broad, cell-intrinsic mechanism for regulating the p53-dependent cellular response to stress through differential regulation ofcis-regulatory elements.

Use of Flexible Materials with a Novel Pressure Driven Equibiaxial Cell Stretching Device for Mechanical Stimulation of Single Mammalian Cells

2003 ◽  
Vol 773 ◽  
Author(s):  
James D. Kubicek ◽  
Stephanie Brelsford ◽  
Philip R. LeDuc
Keyword(s):  
Cell Fate ◽  
Mechanical Stimulation ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Single Cells ◽  
Complex Nature ◽  
Cellular Behavior ◽  
Cell Stretching ◽  
Stimulation Of ◽  
Pressure Driven

AbstractMechanical stimulation of single cells has been shown to affect cellular behavior from the molecular scale to ultimate cell fate including apoptosis and proliferation. In this, the ability to control the spatiotemporal application of force on cells through their extracellular matrix connections is critical to understand the cellular response of mechanotransduction. Here, we develop and utilize a novel pressure-driven equibiaxial cell stretching device (PECS) combined with an elastomeric material to control specifically the mechanical stimulation on single cells. Cells were cultured on silicone membranes coated with molecular matrices and then a uniform pressure was introduced to the opposite surface of the membrane to stretch single cells equibiaxially. This allowed us to apply mechanical deformation to investigate the complex nature of cell shape and structure. These results will enhance our knowledge of cellular and molecular function as well as provide insights into fields including biomechanics, tissue engineering, and drug discovery.

scholarly journals Stimulation of the Human Heat Shock Protein 70 Promoter in Vitro by Simian Virus 40 Large T Antigen

1989 ◽  
Vol 264 (27) ◽  
pp. 16160-16164
Author(s):  
I C Taylor ◽  
W Solomon ◽  
B M Weiner ◽  
E Paucha ◽  
M Bradley ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Heat Shock Protein 70 ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Large T Antigen ◽  
Human Heat Shock Protein ◽  
Stimulation Of

scholarly journals Overexpression of antizyme in the hearts of transgenic mice prevents the isoprenaline-induced increase in cardiac ornithine decarboxylase activity and polyamines, but does not prevent cardiac hypertrophy

2000 ◽  
Vol 350 (3) ◽  
pp. 645-653 ◽  
Author(s):  
Caroline A. MACKINTOSH ◽  
David J. FEITH ◽  
Lisa M. SHANTZ ◽  
Anthony E. PEGG
Keyword(s):  
Transgenic Mice ◽  
Ornithine Decarboxylase ◽  
Prolonged Exposure ◽  
Constitutive Expression ◽  
Decarboxylase Activity ◽  
Cardiac Growth ◽  
Polyamine Content ◽  
Transgenic Lines ◽  
Response To Stress ◽  
Polyamine Uptake

Two lines of transgenic mice were produced with constitutive expression of antizyme-1 in the heart, driven from the cardiac α-myosin heavy chain promoter. The use of engineered antizyme cDNA in which nucleotide 205 had been deleted eliminated the need for polyamine-mediated frameshifting, normally necessary for translation of antizyme mRNA, and thus ensured the constitutive expression of antizyme. Antizyme-1 is thought to be a major factor in regulating cellular polyamine content, acting both to inhibit ornithine decarboxylase (ODC) activity and to target it for degradation, as well as preventing polyamine uptake. The two transgenic lines had substantial, but different, levels of antizyme in the heart, as detected by Western blotting and by the ability of heart extracts to inhibit exogenous purified ODC. Despite the high levels of antizyme, endogenous ODC activity was not completely abolished, with 10– 39% remaining, depending on the transgenic line. Additionally, a relatively small decrease (30–32%) in cardiac spermidine content was observed, with levels of putrescine and spermine unaffected. Interestingly, although the two lines of transgenic mice had different antizyme expression levels, they had almost identical cardiac polyamine content. When treated with a single acute dose of isoprenaline (isoproterenol), cardiac ODC activity and putrescine content were substantially increased (by 14-fold and 4.7-fold respectively) in non-transgenic littermate mice, but these increases were completely prevented in the transgenic mice from both founder lines. Prolonged exposure to isoprenaline also caused increases in cardiac ODC activity and polyamine content, as well as an increase in cardiac growth, in non-transgenic mice. Although the increases in cardiac ODC activity and polyamine content were prevented in the transgenic mice from both founder lines, the increase in cardiac growth was unaffected. These transgenic mice thus provide a valuable model system in which to study the importance of polyamine levels in cardiac growth and electrophysiology in response to stress.

scholarly journals Insulin Promotes the Association of Heat Shock Protein 90 with the Inositol 1,4,5-Trisphosphate Receptor to Dampen Its Ca2+ Release Activity

Endocrinology ◽  
2009 ◽  
Vol 150 (5) ◽  
pp. 2190-2196 ◽  
Author(s):  
Nathalie Nguyen ◽  
Nancy Francoeur ◽  
Valérie Chartrand ◽  
Klaus Klarskov ◽  
Gaétan Guillemette ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Protein Interactions ◽  
Mammalian Target Of Rapamycin ◽  
Src Kinase ◽  
Target Of Rapamycin ◽  
Resting Cells ◽  
Release Channel ◽  
Inositol 1,4,5 Trisphosphate ◽  
Trisphosphate Receptor

The inositol 1,4,5-trisphosphate receptor (IP3R) is a Ca2+ release channel that plays a pivotal role in regulating intracellular Ca2+ levels in resting cells. Three isoforms of IP3Rs have been identified, and they all possess a large regulatory domain that covers about 60% of the protein. This regulation is accomplished by interaction with small molecules, posttranslational modifications, and mostly protein-protein interactions. In our search for new binding partners of the IP3R, we found that 90-kDa heat-shock protein (Hsp90) binds to the IP3R. This interaction increased on stimulation of HEK293T6.11 cells with insulin but not with Gq protein-coupled receptor (GqPCR) agonists. Moreover, the Hsp90 inhibitor geldanamycin (GA) disrupted the interaction between Hsp90 and the IP3R. Pretreatment of HEK293T6.11 cells with GA greatly increased the intracellular Ca2+ release induced by a GqPCR agonist. Insulin alone did not induce any intracellular Ca2+ release. However, insulin diminished the intracellular Ca2+ release induced by a GqPCR agonist. Interestingly, GA abolished the inhibitory effect of insulin on GqPCR-induced intracellular Ca2+ release. Furthermore, in our search for a mechanistic explanation to this phenomenon, we found that inhibition of kinases activated downstream of the insulin receptor greatly increased the interaction between Hsp90 and the IP3R. Of greater interest, we found that the simultaneous inhibition of mammalian target of rapamycin and the Src kinase almost completely disrupted the interaction between Hsp90 and the IP3R. These results demonstrate that insulin promotes the interaction of Hsp90 with the IP3R to dampen its Ca2+ release activity by a complex mechanism involving mammalian target of rapamycin and the Src kinase.

scholarly journals Acceleration of Sodium-Calcium Exchange Activity during ATP-induced Calcium Release in Transfected Chinese Hamster Ovary Cells

1997 ◽  
Vol 109 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Melissa Vázquez ◽  
Yu Fang ◽  
John P. Reeves
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Chinese Hamster Ovary ◽  
Calcium Release ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
Kinase C ◽  
Stimulation Of ◽  
Exchange Activity

The P2U purinergic agonist ATP (0.3 mM) elicited an increase in [Ca2+]i due to Ca2+ release from intracellular stores in transfected Chinese hamster ovary cells that express the bovine cardiac Na+/Ca2+ exchanger (CK1.4 cells). The following observations indicate that ATP-evoked Ca2+ release was accompanied by a Ca2+- dependent regulatory activation of Na+/Ca2+ exchange activity: Addition of extracellular Ca2+ (0.7 mM) 0–1 min after ATP evoked a dramatic rise in [Ca2+]i in Na+-free media (Li+ substitution) compared to Na+-containing media; no differences between Na+- and Li+-based media were observed with vector-transfected cells. In the presence of physiological concentrations of extracellular Na+ and Ca2+, the ATP-evoked rise in [Ca2+]i declined more rapidly in CK1.4 cells compared to control cells, but then attained a long-lived plateau of elevated [Ca2+]i which eventually came to exceed the declining [Ca2+]i values in control cells. ATP elicited a transient acceleration of exchange-mediated Ba2+ influx, consistent with regulatory activation of the Na+/Ca2+ exchanger. The acceleration of Ba2+ influx was not observed in vector-transfected control cells, or in CK1.4 cells in the absence of intracellular Na+ or when the Ca2+ content of the intracellular stores had been reduced by prior treatment with ionomycin. The protein kinase C activator phorbol 12-myristate 13-acetate attenuated the exchange-mediated rise in [Ca2+]i under Na+-free conditions, but did not inhibit the ATP-evoked stimulation of Ba2+ influx. The effects of PMA are therefore not due to inhibition of exchange activity, but probably reflect the influence of protein kinase C on other Ca2+ homeostatic mechanisms. We conclude that exchange activity is accelerated during ATP-evoked Ca2+ release from intracellular stores through regulatory activation by increased [Ca2+]i. In the absence of extracellular Ca2+, the stimulation of exchange activity is short-lived and follows the time course of the [Ca2+]i transient; in the presence of extracellular Ca2+, we suggest that the exchanger remains activated for a longer period of time, thereby stabilizing and prolonging the plateau phase of store-dependent Ca2+ entry.

Sign in / Sign up

Export Citation Format

Share Document