Regular ArticleModulation of Bradykinin-Induced Calcium Signals by Oxidative Stress in PC12 Cells
Abstract
The influence of oxidative stress on agonist-stimulated changes of intracellular free calcium and inositol trisphosphate in the neurosecretory PC12 cell line was investigated. The oxidant H2O2 modulated the bradykinin-induced calcium signal by decreasing the initial peak and the plateau phase in the same manner as tetraphorbolacetate, an activator of protein kinase C. Inositol trisphosphate formation, induced by bradykinin was also decreased by oxidative stress. Thiol protecting agents were able to restore the altered signal. In contrast to this, radical quenching substances had no influence on calcium signals in stressed cells. Inhibitors of several protein kinases, such as protein kinase C, protein kinase A, or cyclic GMP-dependent protein kinase showed the ability to protect the plateau phase of calcium signals against oxidative stress, but not the peak response. These results indicate that under the influence of oxidative stress multiple targets within the signal transduction cascades are affected.
References (0)
Cited by (15)
The effect of hydrogen peroxide upon β-adrenoceptor density and function in C6 rat glioma cells
1999, Neurochemistry InternationalHydrogen peroxide has been suggested to play an important role in the pathogenesis of Alzheimerfn3s disease. In the present study, the effects of hydrogen peroxide upon the functional integrity of β-adrenoceptors have been investigated in C6 glioma cells. Treatment of cells for 24 h with hydrogen peroxide in serum-free medium produced a concentration-dependent cell toxicity, seen both using cell counting and LDH release into medium as end point. There were no large nor consistent changes in either the density of cell surface β1, or β2-adrenoceptors, measured using the hydrophilic ligand [3H](−)-CGP 12177, nor in either basal, forskolin and isoprenaline-stimulated cAMP responses, following hydrogen peroxide treatment. It is concluded that the decreased adenylyl cyclase activity and responsiveness to Gs stimulation found in post-mortem brain samples from Alzheimers disease autopsy cases is unlikely to be mediated by hydrogen peroxide.
Characterisation of calcium signalling in DT40 chicken B-cells
1998, Biochimica et Biophysica Acta - Molecular Cell ResearchThe chicken DT40 pre-B-cell line is becoming a potent experimental tool in the elucidation of higher organism cellular functions due to its unique genetic tractability. While several publications have described the effects of disruption of a range of genes in DT40 cells on calcium signalling, there has been no general overview of Ca2+ responses in wild-type cells. Here, we present experimental data comparing and contrasting the calcium responses to a range of agonists, such as αIgM, H2O2 and thapsigargin, applied singly or consecutively in the presence or absence of extracellular calcium. Briefly, we show that calcium release is from thapsigargin-sensitive and also -insensitive stores. This release results in, or is concomitant with, calcium entry across the plasma membrane through store-operated, receptor-operated and possibly L-type like Ca2+ channels. The agonists activate these pathways differentially producing a wide range of different sized and shaped Ca2+ signals. Furthermore, we report that Ca2+ responses in DT40 cells are dependent on the growth conditions. The presence of 1% chicken serum in the growth medium increased amplitudes of calcium responses and enhanced the sustained phase of the αIgM response, while 10 μM β-mercaptoethanol in the medium (not, however, present during calcium measurements) resulted in more transient H2O2 responses and larger amplitude αIgM responses while failing to affect thapsigargin responses. The possible causes of these effects and their importance in comparing data from different studies on DT40 cells is discussed.
Comparison of the effects of hydrogen peroxide, 4-hydroxy-2-nonenal and β-amyloid (25-35) upon calcium signalling
1998, Neurochemistry InternationalThe neurotoxic β-amyloid (Aβ) peptide fragment Aβ(25–35) has been suggested to exert its deleterious effects on cells via production of hydrogen peroxide. In human platelets and in the presence of DMSO to prevent production of hydroxyl radicals from hydrogen peroxide, both Aβ(25–35) and hydrogen peroxide were found to increase intracellular calcium levels. Hydrogen peroxide in addition reduced the calcium response to thrombin, whereas this was not seen with Aβ(25–35). A similar pattern of effects to those seen with hydrogen peroxide were also seen with the neurotoxic aldehyde lipid peroxidation product 4-hydroxy-2-nonenal (HNE). The initial increase in calcium produced by hydrogen peroxide was not affected by EGTA, but was partially prevented by dithiothreitol. The calcium response to Aβ(25-35) which was also seen with Aβ(1- 40) and Aβ(1-42) but not with the inactive peptide Aβ(40-1) consisted of an EGTA-sensitive and an EGTA-resistant component, of which the latter was also sensitive to DTT. Hydrogen peroxide increased basal phosphoinositide breakdown in rat brain miniprisms and decreased the responses to nor- adrenaline, carbachol and veratrine. The specific binding of 3 H inositol -1,4,5 -trisphosphate ( 3 H Ins(1,4,5)P3 ) to its receptor recognition site in human platelet membranes was increased by Aβ(25-35) but remained unchanged following hydrogen peroxide treatment. It is concluded that under conditions where production of hydroxyl radicals from hydrogen peroxide is blocked, hydrogen peroxide and Aβ(25-35) produce their effects on calcium by affecting the mobilisation of intracellular calcium. The qualitative differences in the calcium responses of these two agents can be explained (a) by an additional effect of Aβ(25-35) upon calcium entry and (b) by differences in their effects upon the Ins(1,4,5)P3 receptor. ©1998 Elsevier Science Ltd. All rights reserved.
The sulphydryl oxidizing reagent diamide affects phosphoinositide-mediated signal transduction: Implications for the pathogenesis of Alzheimer's disease
1998, Cellular SignallingIn fura-2–labelled human platelets, the thiol oxidising agent diamide decreases the intracellular calcium response to thrombin and serotonin without affecting the basal calcium levels. The effect of diamide on the thrombin response could be prevented by pre-treatment with dithiothreitol (DTT) and reduced when DTT was added 60 s after diamide. The effects of diamide and hydrogen peroxide on the thrombin response were additive. Hydrogen peroxide also produced a calcium response per se, but this response was not affected by diamide. Hydrogen peroxide increased rat brain phosphoinositide hydrolysis and reduced the response to carbachol and noradrenaline, whereas diamide was without effect. The binding of [3H]inositol-1,4,5-trisphosphate to human platelet membranes was inhibited by diamide but not by hydrogen peroxide. Thus diamide affects the phosphoinositide signal transduction pathway in a qualitatively different manner from that found with hydrogen peroxide. It is suggested that oxidative stress may contribute to the disturbances in the phosphoinositide transduction pathway that are found in Alzheimer’s disease.
The role of the phosphoinositide signalling system in the pathogenesis of sporadic Alzheimer's disease: A hypothesis
1997, Brain Research ReviewsGreat advances have been made in recent years in our knowledge of the genetic mutations found in early onset familial Alzheimer's disease (AD) and their pathological consequences. The pathogenesis of sporadic AD, on the other hand, is less clear, although a central role of oxidative stress is indicated. In the AD brain, severe dysfunctions in the phosphoinositide signalling pathway have been reported. In view of the fact that (a) oxidative stress can adversely affect phosphoinositide breakdown and hence diacylglycerol-mediated activation of protein kinase C and (b) protein kinase C activation reduces the production of β-amyloid peptide from amyloid precursor protein, it is possible that this represents a pathogenic pathway whereby oxidative stress can lead to amyloid deposition and the development of the disease.
Deferoxamine-induced cytotoxicity in human neuronal cell lines: protection by free radical scavengers
1995, Toxicology LettersDeferoxamine (DFO) caused decreased viability of human neuronal tumor cells (SK-N-MC neuroblastoma and U-373 MG astrocytoma) in a dose-dependent manner. The addition of stoichiometric amounts of ferric ions did not decrease the cytotoxic effect of DFO on the neuroblastoma cells. However, the cotreatments with various antioxidants, hydroxyl radical scavengers or intracellular Ca2+ release blockers significantly protected against the effects of DFO. These results suggest that DFO-induced cytoxicity may be not due to chelating iron, but due to the production of hydroxyl radicals and that intracellular Ca2+ may play a role in the cytotoxic effects of DFO.