1
|
Michelangeli F, Mohammed NA, Jones B, Tairu M, Al-Mousa F. Cytotoxicity by endocrine disruptors through effects on ER Ca 2+ transporters, aberrations in Ca 2+ signalling pathways and ER stress. FEBS Open Bio 2024. [PMID: 39138623 DOI: 10.1002/2211-5463.13880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/24/2024] [Accepted: 08/05/2024] [Indexed: 08/15/2024] Open
Abstract
Concerns regarding man-made organic chemicals pervading our ecosystem and having adverse and detrimental effects upon organisms, including man, have now been studied for several decades. Since the 1970s, some environmental pollutants were identified as having endocrine disrupting affects. These endocrine disrupting chemicals (EDC) were initially shown to have estrogenic or anti-estrogenic properties and some were also shown to bind to a variety of hormone receptors. However, since the 1990s it has also been identified that many of these EDC additionally, have the ability of causing abnormal alterations in Ca2+ signalling pathways (also commonly involved in hormone signalling), leading to exaggerated elevations in cytosolic [Ca2+] levels, that is known to cause activation of a number of cell death pathways. The major emphasis of this review is to present a personal perspective of the evidence for some types of EDC, specifically alkylphenols and brominated flame retardants (BFRs), causing direct effects on Ca2+ transporters (mainly the SERCA Ca2+ ATPases), culminating in acute cytotoxicity and cell death. Evidence is also presented to indicate that this Ca2+ATPase inhibition, which leads to abnormally elevated cytosolic [Ca2+], as well as a decreased luminal ER [Ca2+], which triggers the ER stress response, are both involved in acute cytotoxicity.
Collapse
Affiliation(s)
- Francesco Michelangeli
- Chester Medical School, University of Chester, UK
- School of Biosciences, University of Birmingham, UK
| | - Noor A Mohammed
- School of Biosciences, University of Birmingham, UK
- Department of Biology, University of Duhok, Iraq
| | - Brogan Jones
- Chester Medical School, University of Chester, UK
| | | | - Fawaz Al-Mousa
- General Directorate of Poison Control Centre, Ministry of Health, Riyadh, Saudi Arabia
| |
Collapse
|
2
|
Peterková L, Kmoníčková E, Ruml T, Rimpelová S. Sarco/Endoplasmic Reticulum Calcium ATPase Inhibitors: Beyond Anticancer Perspective. J Med Chem 2020; 63:1937-1963. [PMID: 32030976 DOI: 10.1021/acs.jmedchem.9b01509] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The sarco/endoplasmic reticulum calcium ATPase (SERCA), which plays a key role in the maintenance of Ca2+ ion homeostasis, is an extensively studied enzyme, the inhibition of which has a considerable impact on cell life and death decision. To date, several SERCA inhibitors have been thoroughly studied and the most notable one, a derivative of the sesquiterpene lactone thapsigargin, is gradually approaching a clinical application. Meanwhile, new compounds with SERCA-inhibiting properties of natural, synthetic, or semisynthetic origin are being discovered and/or developed; some of these might also be suitable for the development of new drugs with improved performance. This review brings an up-to-date comprehensive overview of recently discovered compounds with the potential of SERCA inhibition, discusses their mechanism of action, and highlights their potential clinical applications, such as cancer treatment.
Collapse
Affiliation(s)
- Lucie Peterková
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28, Prague 6, Czech Republic
| | - Eva Kmoníčková
- Faculty of Medicine in Pilsen, Charles University, Alej Svobody 76, 323 00 Pilsen, Czech Republic
| | - Tomáš Ruml
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28, Prague 6, Czech Republic
| | - Silvie Rimpelová
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28, Prague 6, Czech Republic.,Faculty of Medicine in Pilsen, Charles University, Alej Svobody 76, 323 00 Pilsen, Czech Republic
| |
Collapse
|
3
|
Menzikov SA, Morozov SG. Involvement of brain GABA AR-coupled Cl -/HCO 3--ATPase in phenol-induced the head-twitching and tremor responses in rats. Neurotoxicology 2018; 71:122-131. [PMID: 30590068 DOI: 10.1016/j.neuro.2018.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/19/2018] [Accepted: 12/21/2018] [Indexed: 11/26/2022]
Abstract
Phenol-induced neurotoxicity manifests as twitching/tremor and convulsions, but its molecular mechanisms underlying the behavioral responses remain unclear. We assessed the role of the brain Cl-/HCO3--ATPase in behavioral responses in rats following an in vivo intraperitoneal injection of phenol (20-160 mg/kg). Low concentrations of phenol (20-80 mg/kg) increased the ATPase activity as well as the head twitching responses in rat, whereas higher phenol concentrations (>60 mg/kg) increased the tremor but reduced the ATPase activity. At phenol concentrations >120 mg/kg, no ATPase activity was detected. Phenobarbital (10 mg/kg) and picrotoxin (1 mg/kg) as well as o-vanadate (2 mg/kg), significantly prevented (˜55-70%) the phenol-induced change in the behavioral responses and completely restored the enzyme activity. In vitro experiments confirmed that phenol stimulated the Cl-/HCO3--ATPase activity at low concentrations, but had no stimulating effect on other transport ATPases. Low doses of phenol increased the formation of phosphoprotein and the rate of ATP-consuming Cl- transport by the reconstituted enzyme. The present findings provide evidence that phenol-induced neurotoxicity involves the Cl-/HCO3--ATPase in the behavioral responses in mammals and indicate the potential benefit of this enzyme as a target for the treatment of head twitching and other types of tremor diseases.
Collapse
Affiliation(s)
- Sergey A Menzikov
- Institute of General Pathology and Pathological Physiology, 8, Baltiyskaya st., Moscow, 125315, Russia.
| | - Sergey G Morozov
- Institute of General Pathology and Pathological Physiology, 8, Baltiyskaya st., Moscow, 125315, Russia
| |
Collapse
|
4
|
Menzikov SA. Effect of phenol on the GABAAR-coupled Cl−/HCO3−-ATPase from fish brain: An in vitro approach on the enzyme function. Toxicol In Vitro 2018; 46:129-136. [DOI: 10.1016/j.tiv.2017.09.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/24/2017] [Accepted: 09/25/2017] [Indexed: 11/30/2022]
|
5
|
Vargas-Medrano J, Sierra-Fonseca JA, Plenge-Tellechea LF. 1,2-Dichlorobenzene affects the formation of the phosphoenzyme stage during the catalytic cycle of the Ca(2+)-ATPase from sarcoplasmic reticulum. BMC BIOCHEMISTRY 2016; 17:5. [PMID: 26968444 PMCID: PMC4788898 DOI: 10.1186/s12858-016-0061-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 03/02/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND 1,2-Dichlorobenzene (1,2-DCB) is a benzene-derived molecule with two Cl atoms that is commonly utilized in the synthesis of pesticides. 1,2-DCB can be absorbed by living creatures and its effects on naturally-occurring enzymatic systems, including the effects on Ca(2+)-ATPases, have been poorly studied. Therefore, we aimed to study the effect of 1,2-DCB on the Ca(2+)-ATPase from sarcoplasmic reticulum (SERCA), a critical regulator of intracellular Ca(2+) concentration. RESULTS Concentrations of 0.05-0.2 mM of 1,2-DCB were able to stimulate the hydrolytic activity of SERCA in a medium-containing Ca(2+)-ionophore. At higher concentrations (0.25-0.75 mM), 1,2-DCB inhibited the ATP hydrolysis to ~80 %. Moreover, ATP hydrolysis and Ca(2+) uptake in a medium supported by K-oxalate showed that starting at 0.05 mM,1,2-DCB was able to uncouple the ratio of hydrolysis/Ca(2+) transported. The effect of this compound on the integrity of the SR membrane loaded with Ca(2+) remained unaffected. Finally, the analysis of phosphorylation of SERCA by [γ-(32)P]ATP, starting under different conditions at 0° or 25 °C showed a reduction in the phosphoenzyme levels by 1,2-DCB, mostly at 0 °C. CONCLUSIONS The temperature-dependent decreased levels of phosphoenzyme by 1,2-DCB could be due to the acceleration of the dephosphorylation mechanism - E2P · Ca2 state to E2 and Pi, which explains the uncoupling of the ATP hydrolysis from the Ca(2+) transport.
Collapse
Affiliation(s)
- Javier Vargas-Medrano
- Present address: Department of Biomedical Sciences, Center of Emphasis for Neurosciences, Texas Tech University Health Science Center, El Paso, TX, 79905, USA
| | - Jorge A Sierra-Fonseca
- Present address: Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, 79968, USA
| | - Luis F Plenge-Tellechea
- Departamento de Ciencias Químico Biológicas, Laboratorio de Biología Molecular y Bioquímica (Edif. T-216), Instituto de Ciencias Biomédicas, Universidad Autónoma de Ciudad Juárez, Plutarco Elías Calles #1210 Fovissste Chamizal, Ciudad Juárez, Chihuahua, C.P. 32310, Mexico.
| |
Collapse
|
6
|
Mariel AC, Alejandra BP, Silvia PCC. Developmental toxicity and risk assessment of nonylphenol to the South American toad, Rhinella arenarum. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2014; 38:634-642. [PMID: 25195099 DOI: 10.1016/j.etap.2014.08.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 08/15/2014] [Accepted: 08/18/2014] [Indexed: 06/03/2023]
Abstract
The toxicity of Nonylphenol, an emerging pollutant, on the common South American toad Rhinella arenarum was stage and time dependent, thus Median Lethal Concentrations (LC50) for acute (96h), short-term chronic (168h) and chronic exposure (336h) were 1.06; 0.96 and 0.17mgNP/L from embryonic period (S.4), whereas for exposure from larvae (S.25), LC50 remained constant at 0.37mgNP/L from 96h to 168h, decreasing to 0.11mgNP/L at 336h. NOEC-168h for exposure from embryos was 0.025mgNP/L. The Teratogenic Potential (NOEC-lethality/NOEC-sublethal effects) was 23 times higher than the threshold value, indicating a high risk for embryos to be malformed in absence of significant lethality and representing a threat for the species conservation. By comparing with other amphibians, the early development of R. arenarum was very sensitive to NP. The results highlight the relevance of extending the exposure time and look for the most sensitive stage in order to perform the bioassays for conservation purposes.
Collapse
Affiliation(s)
- Aronzon Carolina Mariel
- Instituto de Investigación e Ingeniería Ambiental (3iA) Universidad Nacional de San Martín. Campus Miguelete, 25 de Mayo y Francia. C.P.: 1650. San Martín, Provincia de Buenos Aires, Argentina
| | - Babay Paola Alejandra
- Gerencia Química, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499 1650 San Martín, Provincia de Buenos Aires, Argentina
| | - Pérez Coll Cristina Silvia
- Instituto de Investigación e Ingeniería Ambiental (3iA) Universidad Nacional de San Martín. Campus Miguelete, 25 de Mayo y Francia. C.P.: 1650. San Martín, Provincia de Buenos Aires, Argentina.
| |
Collapse
|
7
|
Ogunbayo OA, Michelangeli F. Related flavonoids cause cooperative inhibition of the sarcoplasmic reticulum Ca²⁺ ATPase by multimode mechanisms. FEBS J 2013; 281:766-77. [PMID: 24238016 DOI: 10.1111/febs.12621] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 11/09/2013] [Accepted: 11/11/2013] [Indexed: 11/30/2022]
Abstract
Flavonoids are group of plant-derived hydroxylated polycyclic molecules found in fruit and vegetables. They are known to bio-accumulate within humans and are considered to have beneficial health effects, including cancer chemoprotection. One mechanism proposed to explain this is that they are able to induce apoptosis in cancer cells by inhibiting a variety of kinases and also the Ca²⁺ ATPase. An investigation was undertaken with respect to the mechanism of inhibition for three flavonoids: quercetin, galangin and 3,6 dihydroxyflavone (3,6-DHF). Each inhibited the Ca²⁺ ATPase with K(i) values of 8.7, 10.3 and 5.4 μM, respectively, showing cooperative inhibition with n ~ 2. Given their similar structures, the flavonoids showed several differences in their mechanisms of inhibition. All three flavonoids stabilized the ATPase in the E₁ conformation and reduced [³²P]-ATP binding. However, both galangin and 3,6-DHF increased the affinity of Ca²⁺ for the ATPase by decreasing the Ca²⁺-dissociation rate constant, whereas quercetin had little effect. Ca²⁺-induced changes in tryptophan fluorescence levels were reduced in the presence of 3,6-DHF and galangin (but not with quercetin), indicating that Ca²⁺-associated changes within the transmembrane helices are altered. Both galangin and quercetin reduced the rates of ATP-dependent phosphorylation and dephosphorylation, whereas 3,6-DHF did not. Modelling studies suggest that flavonoids could potentially bind to two sites: one directly where nucleotides bind within ATP binding site and the other at a site close by. We hypothesize that interactions of these two neighbouring sites may account for both the cooperative inhibition and the multimode mechanisms of action seen with related flavonoids.
Collapse
Affiliation(s)
- Oluseye A Ogunbayo
- School of Biosciences, University of Birmingham, UK; Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, UK
| | | |
Collapse
|
8
|
Al-Mousa F, Michelangeli F. The sarcoplasmic-endoplasmic reticulum Ca(2+)-ATPase (SERCA) is the likely molecular target for the acute toxicity of the brominated flame retardant hexabromocyclododecane (HBCD). Chem Biol Interact 2013; 207:1-6. [PMID: 24189551 DOI: 10.1016/j.cbi.2013.10.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 10/16/2013] [Accepted: 10/23/2013] [Indexed: 10/26/2022]
Abstract
Hexabromocyclododecane (HBCD) is a widely utilised brominated flame retardant (BFR). It has been shown to bio-accumulate within organisms, including man, and possibly cause neurological disorders. The acute neurotoxicity of HBCD, and six other unrelated BFRs, were assessed in SH-SY5Y human neuroblastoma cells by 24h viability assays and HBCD proved to be the most lethal (LC50, 3μM). In addition, the effects of these BFRs were also assessed for their potency at inhibiting the sarcoplasmic-endoplasmic reticulum Ca(2+) ATPase (SERCA) derived from the SH-SY5Y cells and again HBCD was the most potent (IC50, 2.7μM). The data for the other BFRs tested showed a direct correlation (coefficient 0.94) between the potencies of inducing cell death and inhibiting the Ca(2+) ATPase, indicating that SERCA is likely to be the molecular target for acute toxicity. Mechanistic studies of HBCD on the Ca(2+) ATPase suggest that it affects ATP binding, phosphorylation as well as the E2 to E1 transition step.
Collapse
Affiliation(s)
- Fawaz Al-Mousa
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | | |
Collapse
|
9
|
Michalec FG, Holzner M, Menu D, Hwang JS, Souissi S. Behavioral responses of the estuarine calanoid copepod Eurytemora affinis to sub-lethal concentrations of waterborne pollutants. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 138-139:129-138. [PMID: 23735933 DOI: 10.1016/j.aquatox.2013.05.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 04/24/2013] [Accepted: 05/01/2013] [Indexed: 06/02/2023]
Abstract
Estuarine waters contain a variety of chemicals which affect to various extents the behavior of aquatic organisms. Little is known, however, on the behavioral response of copepods. The present study shows the results of laboratory experiments investigating the immediate effects of sub-lethal concentrations of three commonly found contaminants on the three-dimensional swimming behavior of the estuarine calanoid copepod Eurytemora affinis. Nonylphenol at 2 μg L⁻¹, cadmium at 45 n gL⁻¹ and a mixture of low to medium molecular weight polycyclic aromatic hydrocarbons at 40 ng L⁻¹ all affected the swimming behavior of E. affinis adults, increasing both swimming speed and activity. In most cases, effects were observable within 30 min of exposure and persisted or faded during a period of depuration in uncontaminated water of similar duration. In ovigerous females exposed to Cd and PAHs, effects appeared to be more pronounced during the depuration period, suggesting that carrying ovisacs may impair recovery. We quantified differences in the distribution of swimming speed values by considering the relative frequencies of periods of break, slow and fast swimming and we observed a trend toward faster movements in the presence of pollutants. The degree of trajectory complexity, estimated through their fractal dimension, was unaffected by pollutants. Since both narcotic and non-narcotic pollutants induced hyperactivity, our results suggest that changes in behavior after a short-term exposure may be independent of the general mode of action of the chemicals. The increase in speed and activity resembles an escape reaction permitting copepods to evade stressful conditions. Overall, these results indicate that environment-relevant concentrations of pollutants can induce rapid changes in copepod behavior. Since behavioral processes represent a fundamental element in the ecology of copepods, our results raise concern about the effects of background levels of pollution on a major component of the plankton community. The long-term response of copepods to waterborne pollutants, their synergistic effects and their interactions with other environmental factors need further investigation.
Collapse
|
10
|
Chang LL, Wun WSA, Wang PS. Effects of nonylphenol on aldosterone release from rat zona glomerulosa cells. Chem Biol Interact 2011; 195:11-7. [PMID: 22001352 DOI: 10.1016/j.cbi.2011.09.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2011] [Revised: 09/25/2011] [Accepted: 09/27/2011] [Indexed: 11/30/2022]
Abstract
Alkylphenol ethoxylate, which consists of approximately 80% nonylphenol ethoxylate (NPE), is a major nonionic surfactant. Nonylphenol (NP), the primary degradation product of NPE, has been reported to interfere with reproduction in fish, reptiles, and mammals by inducing cell death in the gonads and by affecting other reproductive parameters. However, the effects of NP on rat adrenal zona glomerulosa cells (ZG) and the underlying mechanisms remain unclear. In this study, we explored the effects of NP on aldosterone release. ZG cells were incubated with NP in the presence or absence of the secretagogues angiotensin II (ANG II), potassium, 8-Br-cAMP, 25-OH-cholesterol, corticosterone or cyclopiazonic acid (CPA). After performing radioimmunoassay (RIA) and Western blot analysis, we found that (1) NP stimulated aldosterone release in cells induced by ANG II, KCl, 8-Br-cAMP, 25-OH-cholesterol, corticosterone, and CPA; (2) NP triggered the release of higher amounts of pregnenolone in cells treated with vehicle and 25-OH-cholesterol+trilostane than in cells treated with other compounds; and (3) the stimulatory effect of NP seemed to be mediated through steroidogenic acute regulatory protein (StAR) and aldosterone synthase activity. These observations suggest that the effects of NP are mediated via increased free Ca(2+) in the cytoplasm.
Collapse
Affiliation(s)
- Ling-Ling Chang
- Department of Chemical and Materials Engineering, Chinese Culture University, Taipei, Taiwan, ROC
| | | | | |
Collapse
|
11
|
Abstract
The SERCA (sarcoplasmic/endoplasmic reticulum Ca2+-ATPase) is probably the most extensively studied membrane protein transporter. There is a vast array of diverse inhibitors for the Ca2+ pump, and many have proved significant in helping to elucidate both the mechanism of transport and gaining conformational structures. Some SERCA inhibitors such as thapsigargin have been used extensively as pharmacological tools to probe the roles of Ca2+ stores in Ca2+ signalling processes. Furthermore, some inhibitors have been implicated in the cause of diseases associated with endocrine disruption by environmental pollutants, whereas others are being developed as potential anticancer agents. The present review therefore aims to highlight some of the wide range of chemically diverse inhibitors that are known, their mechanisms of action and their binding location on the Ca2+ ATPase. Additionally, some ideas for the future development of more useful isoform-specific inhibitors and anticancer drugs are presented.
Collapse
|
12
|
Kuo CC, Kuo DH, Huang CJ, Fang YC, Shieh P, Chen FA, Shaw CF, Jan CR. Nonylphenol-induced apoptotic pathways in SCM1 human gastric cancer cells. Drug Dev Res 2009. [DOI: 10.1002/ddr.20355] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
13
|
Deye J, Elam C, Lape M, Ratliff R, Evans K, Paula S. Structure-based virtual screening for novel inhibitors of the sarco/endoplasmic reticulum calcium ATPase and their experimental evaluation. Bioorg Med Chem 2008; 17:1353-60. [PMID: 19117760 DOI: 10.1016/j.bmc.2008.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2008] [Revised: 11/28/2008] [Accepted: 12/07/2008] [Indexed: 10/21/2022]
Abstract
A public compound library with 260,000 compounds was screened virtually by computational docking for novel inhibitors of the transmembrane enzyme sarco/endoplasmic reticulum calcium ATPase (SERCA). Docking was performed with the program GOLD in conjunction with a high resolution X-ray crystal structure of SERCA. Compounds that were predicted to be active were tested in bioassays. Nineteen novel compounds were discovered that were capable of inhibiting the ATP hydrolysis activity of SERCA at concentrations below 50 microM. Crucial enzyme/inhibitor interactions were identified by analyzing the docking-predicted binding poses of active compounds. Like other SERCA inhibitors, the newly discovered compounds are of considerable medicinal interest because of their potential for cancer chemotherapy.
Collapse
Affiliation(s)
- Joel Deye
- Department of Chemistry, Natural Sciences Center, Northern Kentucky University, Highland Heights, KY 41099-1905, USA
| | | | | | | | | | | |
Collapse
|
14
|
Endocrine disrupting alkylphenols: Structural requirements for their adverse effects on Ca2+pumps, Ca2+ homeostasis & Sertoli TM4 cell viability. Chem Biol Interact 2008; 176:220-6. [DOI: 10.1016/j.cbi.2008.08.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 08/04/2008] [Accepted: 08/08/2008] [Indexed: 11/20/2022]
|
15
|
Soares A, Guieysse B, Jefferson B, Cartmell E, Lester JN. Nonylphenol in the environment: a critical review on occurrence, fate, toxicity and treatment in wastewaters. ENVIRONMENT INTERNATIONAL 2008; 34:1033-49. [PMID: 18282600 DOI: 10.1016/j.envint.2008.01.004] [Citation(s) in RCA: 663] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Revised: 01/09/2008] [Accepted: 01/11/2008] [Indexed: 05/20/2023]
Abstract
Nonylphenol is a toxic xenobiotic compound classified as an endocrine disrupter capable of interfering with the hormonal system of numerous organisms. It originates principally from the degradation of nonylphenol ethoxylates which are widely used as industrial surfactants. Nonylphenol ethoxylates reach sewage treatment works in substantial quantities where they biodegrade into several by-products including nonylphenol. Due to its physical-chemical characteristics, such as low solubility and high hydrophobicity, nonylphenol accumulates in environmental compartments that are characterised by high organic content, typically sewage sludge and river sediments, where it persists. The occurrence of nonylphenol in the environment is clearly correlated with anthropogenic activities such as wastewater treatment, landfilling and sewage sludge recycling. Nonylphenol is found often in matrices such as sewage sludge, effluents from sewage treatment works, river water and sediments, soil and groundwater. The impacts of nonylphenol in the environment include feminization of aquatic organisms, decrease in male fertility and the survival of juveniles at concentrations as low as 8.2 microg/l. Due to the harmful effects of the degradation products of nonylphenol ethoxylates in the environment, the use and production of such compounds have been banned in EU countries and strictly monitored in many other countries such as Canada and Japan. Although it has been shown that the concentration of nonylphenol in the environment is decreasing, it is still found at concentrations of 4.1 microg/l in river waters and 1 mg/kg in sediments. Nonylphenol has been referred to in the list of priority substances in the Water Frame Directive and in the 3rd draft Working Document on Sludge of the EU. Consequently there is currently a concern within some industries about the possibility of future regulations that may impose the removal of trace contaminants from contaminated effluents. The significance of upgrading sewage treatment works with advanced treatment technologies for removal of trace contaminants is discussed.
Collapse
Affiliation(s)
- A Soares
- Cranfield University, Centre for Water Science, Cranfield, MK43 0AL, UK.
| | | | | | | | | |
Collapse
|
16
|
Effects of dichlorobenzene on acetylcholine receptors in human neuroblastoma SH-SY5Y cells. Toxicology 2008; 253:28-35. [PMID: 18761391 DOI: 10.1016/j.tox.2008.07.066] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 07/22/2008] [Accepted: 07/22/2008] [Indexed: 11/24/2022]
Abstract
para-Dichlorobenzene (DCB), a deodorant and an industrial chemical, is a highly volatile compound and is known to be an indoor air contaminant. Because of its widespread use and volatility, the toxicity of DCB presents a concern to industrial workers and public. Some toxic aspects of DCB have already been focused but its effects on neuronal signal transduction have been hitherto unknown. The effects of DCB on the cytosolic calcium homeostasis are investigated in human neuroblastoma SH-SY5Y cells in this study. DCB, above 200 microM, was found to induce a rise in cytosolic calcium concentration that could not be counteracted by nicotinic acetylcholine receptor (nAChR) and muscarinic acetylcholine receptor (mAChR) antagonists but was partially inhibited by thapsigargin. To understand the actions of DCB on the acetylcholine receptors, we investigated its effects on the changes of cytosolic calcium concentration following nicotinic AChR stimulation with epibatidine and muscarinic AChR stimulation with methacholine in human neuroblastoma SH-SY5Y cells. DCB inhibited the cytosolic calcium concentration rise induced by epibatidine and methacholine with respective IC(50)s of 34 and 294 microM. The inhibitions of DCB were not the same as thapsigargin's inhibition. In the electrophysiological observations, DCB blocked the influx currents induced by epibatidine. Our findings suggest that DCB interferes with the functional activities of AChR, including its coupling influx currents and cytosolic calcium elevations.
Collapse
|
17
|
Effects of nonylphenol on the calcium signal and catecholamine secretion coupled with nicotinic acetylcholine receptors in bovine adrenal chromaffin cells. Toxicology 2008; 244:77-85. [DOI: 10.1016/j.tox.2007.11.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 10/26/2007] [Accepted: 11/07/2007] [Indexed: 11/22/2022]
|
18
|
Ogunbayo O, Michelangeli F. The widely utilized brominated flame retardant tetrabromobisphenol A (TBBPA) is a potent inhibitor of the SERCA Ca2+ pump. Biochem J 2008; 408:407-15. [PMID: 17784851 PMCID: PMC2267361 DOI: 10.1042/bj20070843] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
TBBPA (tetrabromobisphenol A) is currently the most widely used type of BFR (brominated flame retardant) employed to reduce the combustibility of a large variety of electronic and other manufactured products. Recent studies have indicated that BFRs, including TBBPA, are bio-accumulating within animal and humans. BFRs including TBBPA have also been shown to be cytotoxic and potentially endocrine-disrupting to a variety of cells in culture. Furthermore, TBBPA has specifically been shown to cause disruption of Ca2+ homoeostasis within cells, which may be the underlying cause of its cytotoxicity. In this study, we have demonstrated that TBBPA is a potent non-isoform-specific inhibitor of the SERCA (sarcoplasmic/endoplasmic reticulum Ca2+-ATPase) (apparent K(i) 0.46-2.3 microM), thus we propose that TBBPA inhibition of SERCA contributes in some degree to Ca2+ signalling disruption. TBBPA binds directly to the SERCA without the need to partition into the phospholipid bilayer. From activity results and Ca2+-induced conformational results, it appears that the major effect of TBBPA is to decrease the SERCA affinity for Ca2+ (increasing the K(d) from approx. 1 microM to 30 microM in the presence of 10 microM TBBPA). Low concentrations of TBBPA can quench the tryptophan fluorescence of the SERCA and this quenching can be reversed by BHQ [2,5-di-(t-butyl)-1,4-hydroquinone] and 4-n-nonylphenol, but not thapsigargin, indicating that TBBPA and BHQ may be binding to similar regions in the SERCA.
Collapse
Affiliation(s)
- Oluseye A. Ogunbayo
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - Francesco Michelangeli
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
- To whom correspondence should be addressed (email )
| |
Collapse
|
19
|
Ogunbayo OA, Jensen KT, Michelangeli F. The interaction of the brominated flame retardant: Tetrabromobisphenol A with phospholipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1559-66. [PMID: 17475208 DOI: 10.1016/j.bbamem.2007.03.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 03/09/2007] [Accepted: 03/19/2007] [Indexed: 11/15/2022]
Abstract
Tetrabromobisphenol A (TBBPA) is one of the most widely used members of the family of brominated flame retardants (BFRs). BFRs, including TBBPA have been shown to be widely distributed within the environment and there is growing evidence of their bio-accumulation within animals and man. Toxicological studies have shown that TBBPA can be harmful to cells by modulating a number of cell signalling processes. In this study, we employed fluorescence spectroscopy and differential scanning calorimetry to investigate the interaction of TBBPA with phospholipid membranes, as this is the most likely route for it to influence membrane-associated cellular processes. TBBPA readily and randomly partitions throughout all regions of the phospholipid bilayer with high efficacy [partition coefficient (Log K(p))=5.7+/-0.7]. A decrease in membrane fluidity in both liquid-crystalline and gel-phase membranes was detected at concentrations of TBBPA as low as 2.5 microM. TBBPA also decreases the phase transition temperature of dipalmitoyl phoshatidylcholine (DPPC) membranes and broadened transition peaks, in a fashion similar to that for cholesterol. TBBPA, however, also prefers to partition into membrane regions not too highly enriched with cholesterol. Our findings therefore suggests that, the toxic effects of TBBPA, may at least in part, be due to its lipid membrane binding/perturbing effects, which in turn, could influence biological processes involving cell membranes.
Collapse
Affiliation(s)
- Oluseye A Ogunbayo
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | | | | |
Collapse
|
20
|
Meier S, Andersen TC, Lind-Larsen K, Svardal A, Holmsen H. Effects of alkylphenols on glycerophospholipids and cholesterol in liver and brain from female Atlantic cod (Gadus morhua). Comp Biochem Physiol C Toxicol Pharmacol 2007; 145:420-30. [PMID: 17344102 DOI: 10.1016/j.cbpc.2007.01.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 01/25/2007] [Accepted: 01/26/2007] [Indexed: 10/23/2022]
Abstract
Offshore oil production releases large amounts of lipophilic compounds in produced water into the ocean. In 2004, 143 million m(3) produced water, containing approximately 13 tons of long-chain (>C(4)) alkylphenols (AP), was discharged from installations in the Norwegian sector of the North Sea. Long-chain APs are known to cause endocrine disruption in a number of species. However, relatively little is known about their long-term effects in the marine environment. In the present study, Atlantic cod (Gadus morhua) were exposed (0.02 to 80 mg AP/kg) to a mixture (1:1:1:1) of APs (4-tert-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol and 4-n-heptylphenol) or 17 beta-estradiol (5 mg E2/kg) for 5 weeks and the effect on the fatty acid profile and cholesterol content in the membrane lipids from the liver and the brain was studied. We also determined the interaction between different para-substituted APs and glycerophospholipids (native phospholipids extracted from cod liver and brain) and model phosphatidylcholine (PC 16:0/22:6 n-3) in monolayers with the Langmuir-Blodget technique. The study demonstrated that APs and E2 alter the fatty acid profile in the polar lipids (PL) from the liver to contain more saturated fatty acids (SFA) and less n-3 polyunsaturated fatty acids (n-3 PUFA) compared with control. In the brain of the exposed groups a similar effect was demonstrated, although with higher saturation of the fatty acids found in the neutral lipids (mainly cholesterol ester), but not in the polar lipids. The AP and E2 exposure also gave a decline in the cholesterol levels in the brain. The in vitro studies showed that APs increased the mean molecular areas of the PLs in the monolayers at concentrations down to 5 microM, most likely due to intercalation of the APs between PL molecules. The increase in molecular area increased with the length of the alkyl side chain.
Collapse
Affiliation(s)
- Sonnich Meier
- Institute of Marine Research, Postbox 1870 Nordnes, 5817 Bergen, Norway.
| | | | | | | | | |
Collapse
|
21
|
Wootton LL, Michelangeli F. The effects of the phenylalanine 256 to valine mutation on the sensitivity of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA) Ca2+ pump isoforms 1, 2, and 3 to thapsigargin and other inhibitors. J Biol Chem 2006; 281:6970-6. [PMID: 16410239 DOI: 10.1074/jbc.m510978200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Three isoforms of the sarcoplasmic/endoplasmic reticulum Ca(2+) ATPase (SERCA) are known to exist in mammalian cells. This study investigated the effects of thapsigargin and a variety of commonly used hydrophobic inhibitors on these SERCA isoforms (i.e. SERCA1b, SERCA2b, and SERCA3a), which were transiently expressed in COS-7 cells. In addition, the study assessed whether the introduction of the phenylalanine to valine mutation at position 256 (F256V), known to reduce the potency of thapsigargin inhibition in avian SERCA1, affects the other SERCA isoforms in a similar manner and whether this mutation also affects the inhibition by other inhibitors. This study has shown that the sensitivity to thapsigargin is different for the SERCA isoforms (apparent K(i) values being 0.21, 1.3, and 12 nm for SERCA1b, SERCA2b, and SERCA3a, respectively). The reduction in thapsigargin sensitivity caused by the F256V mutation was also different for the three isoforms, with SERCA2b only being modestly affected by this mutation. Although some of the other inhibitors investigated (i.e. cyclopiazonic acid and curcumin) showed some differences in their sensitivity toward the SERCA isoforms, most were little affected by the F256V mutation, indicating that they inhibit the Ca(2+)-ATPase by binding to sites on SERCA distinct from that of thapsigargin.
Collapse
Affiliation(s)
- Laura L Wootton
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | | |
Collapse
|
22
|
Karlovská J, Uhríková D, Kucerka N, Teixeira J, Devínsky F, Lacko I, Balgavý P. Influence of N-dodecyl-N,N-dimethylamine N-oxide on the activity of sarcoplasmic reticulum Ca2+-transporting ATPase reconstituted into diacylphosphatidylcholine vesicles: Effects of bilayer physical parameters. Biophys Chem 2006; 119:69-77. [PMID: 16223561 DOI: 10.1016/j.bpc.2005.09.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Revised: 08/31/2005] [Accepted: 09/01/2005] [Indexed: 11/19/2022]
Abstract
Sarcoplasmic reticulum Ca-transporting ATPase (EC 3.6.1.38) was isolated from rabbit white muscle, purified and reconstituted into vesicles of synthetic diacylphosphatidylcholines with monounsaturated acyl chains using the cholate dilution method. In fluid bilayers at 37 degrees C, the specific activity of ATPase displays a maximum (31.5+/-0.8 IU/mg) for dioleoylphosphatidylcholine (diC18:1PC) and decreases progressively for both shorter and longer acyl chain lengths. Besides the hydrophobic mismatch between protein and lipid bilayer, changes in the bilayer hydration and lateral interactions detected by small angle neutron scattering (SANS) can contribute to this acyl chain length dependence. When reconstituted into dierucoylphosphatidylcholine (diC22:1PC), the zwitterionic surfactant N-dodecyl-N,N-dimethylamine N-oxide (C12NO) stimulates the ATPase activity from 14.2+/-0.6 to 32.5+/-0.8 IU/mg in the range of molar ratios C12NO:diC22:1PC=0/1.2. In dilauroylphosphatidylcholines (diC12:0PC) and diC18:1PC, the effect of C12NO is twofold-the ATPase activity is stimulated at low and inhibited at high C12NO concentrations. In diC18:1PC, it is observed an increase of activity induced by C12NO in the range of molar ratios C12NO:diC18:1PC< or =1.3 in bilayers, where the bilayer thickness estimated by SANS decreases by 0.4+/-0.1 nm. In this range, the 31P-NMR chemical shift anisotropy increases indicating an effect of C12NO on the orientation of the phosphatidylcholine dipole N(+)-P- accompanied by a variation of the local membrane dipole potential. A decrease of the ATPase activity is observed in the range of molar ratios C12NO:diC18:1PC=1.3/2.5, where mixed tubular micelles are detected by SANS in C12NO+diC18:1PC mixtures. It is concluded that besides hydrophobic thickness changes, the changes in dipole potential and curvature frustration of the bilayer could contribute as well to C12NO effects on Ca(2+)-ATPase activity.
Collapse
Affiliation(s)
- J Karlovská
- Faculty of Pharmacy, Comenius University, Odbojárov 10, 832 32 Bratislava, Slovakia.
| | | | | | | | | | | | | |
Collapse
|
23
|
Pretorius E, Bornman MS. Calcium-mediated aponecrosis plays a central role in the pathogenesis of estrogenic chemical-induced neurotoxicity. Med Hypotheses 2005; 65:893-904. [PMID: 16051444 DOI: 10.1016/j.mehy.2005.03.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Accepted: 03/10/2005] [Indexed: 12/28/2022]
Abstract
Estrogen is traditionally associated with females but is also present in males, and influences aspects of brain chemistry and brain morphology in males, females and also during prenatal development. Humans as well as animals are additionally exposed to environmental products that mimic estrogen activity, also known as endocrine disrupters (EDCs). This hypothesis article investigates the role of estrogen (and also EDCs) in the brain and how it influences the Ca2+ pathway. Ca2+ and its movement in and out of the cell is an extremely important ion controlling normal cell physiology. Any dysfunction in the movement from outside to inside the cell or between organelles may have fundamentally negative effects and the disturbance may even lead to apoptosis and/or necrosis. Therefore we consider whether estrogen and EDCs may alter the Ca2+ physiology and whether these changes may be one of the main causes of interference in physiology that is seen when humans and animals are exposed to EDCs. We come to the conclusion that on a molecular level Ca2+ and Ca2+ fluxes ([Ca2+]i, endocrine disrupting chemicals, redox modulation, mitochondria and cytochrome c followed by apoptosis, necrosis or most likely aponecrosis may contribute to chemical-mediated developmental toxicity. Similarly, we hypothesize that calcium-mediated aponecrosis do not only play a central role in the pathophysiology of estrogenic chemical-induced neurotoxicity, but can contribute to chemical-mediated developmental toxicity in general, thereby affecting almost all cells and organs of the living organism.
Collapse
Affiliation(s)
- E Pretorius
- Department of Anatomy, School of Health Sciences, Medical Faculty of the University of Pretoria, P.O. Box 2034, BMW Building, Pretoria 0001, South Africa.
| | | |
Collapse
|
24
|
Khan SZ, Kirk CJ, Michelangeli F. Alkylphenol endocrine disrupters inhibit IP3-sensitive Ca2+ channels. Biochem Biophys Res Commun 2003; 310:261-6. [PMID: 14521904 DOI: 10.1016/j.bbrc.2003.09.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have investigated the influence of alkylphenol endocrine disrupters and the synthetic estrogen diethylstilbestrol (DES) on inositol-1,4,5-trisphosphate (IP(3))-sensitive Ca(2+) channels from porcine cerebellum and rat testicular membranes. All alkylphenols and DES inhibited the extent of IP(3)-induced Ca(2+) release (IICR) from both cerebellar and testicular microsomes. 4-n-nonylphenol was the most potent compound tested (IC(50), 8 microM). Inhibition of IICR was directly related to the length and hydrophobicity of the alkylphenol side chain. None of the alkylphenols or DES appeared to influence the concentration dependence of IICR nor did they have a significant effect on [3H]IP(3) binding to the membranes. An investigation of the effects of nonylphenol on the transient kinetics of IICR showed that it inhibited the rate constants for both the fast and the slow phases of IICR and also the extent of Ca(2+) release. These results illustrate another mechanism by which these environmental pollutants can disrupt endocrine function without the involvement of estrogen receptors.
Collapse
Affiliation(s)
- Shahla Zafar Khan
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | | | | |
Collapse
|
25
|
Cakmak G, Togan I, Uğuz C, Severcan F. FT-IR spectroscopic analysis of rainbow trout liver exposed to nonylphenol. APPLIED SPECTROSCOPY 2003; 57:835-841. [PMID: 14658663 DOI: 10.1366/000370203322102933] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Nonylphenol (NP) is a biodegradation product of nonylphenol ethoxylates (NPEs) belonging to the alkylphenol ethoxylates (APEs) group. APEs are widely used nonionic surfactants in detergents, herbicides, pesticides, paints, and cosmetics. The present work investigates the effects of NP on rainbow trout (Oncorhynchus mykiss) livers at the molecular level using Fourier transform infrared (FT-IR) spectroscopy. The FT-IR spectra revealed dramatic differences between the NP-treated and control tissues, which mainly indicated that the level of triglycerides increased, the lipid order increased, and the protein concentration decreased in the treated samples. Moreover, it was also found that glycogen levels significantly decreased and the relative content of nucleic acids increased in NP-treated fish. The 17beta-Estradiol-treated fish liver spectra were found to be quite similar to those of NP-treated fish. All these results implied that rainbow trout may offer considerable promise to be used as a bioindicator for NP in the future.
Collapse
Affiliation(s)
- Gülgün Cakmak
- Department of Biological Sciences, Middle East Technical University, 06531, Ankara, Turkey
| | | | | | | |
Collapse
|
26
|
Kirk CJ, Bottomley L, Minican N, Carpenter H, Shaw S, Kohli N, Winter M, Taylor EW, Waring RH, Michelangeli F, Harris RM. Environmental endocrine disrupters dysregulate estrogen metabolism and Ca2+ homeostasis in fish and mammals via receptor-independent mechanisms. Comp Biochem Physiol A Mol Integr Physiol 2003; 135:1-8. [PMID: 12727545 DOI: 10.1016/s1095-6433(02)00366-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Xenoestrogen endocrine disrupters (EDs) in the environment are thought to be responsible for a number of examples of sexual dysfunction that have recently been reported in several species. There is growing concern that these compounds may also cause abnormalities of the male reproductive tract and reduced spermatogenesis in man. Whilst some effects of EDs may be receptor-mediated, there is growing evidence that these compounds can exert potent effects in vivo by directly interacting with cellular enzyme targets. Here we report on, and review, the effects of alkylphenols and other EDs on two such enzymes: (1) sulfotransferases, which convert active estrogenic steroids to inactive steroid sulfates; and (2) Ca(2+)-ATPases, which are responsible for maintaining low, physiological, intracellular Ca(2+) concentrations. These enzymes are potently inhibited by EDs in both fish and mammalian species. The increased concentrations of active estrogens and the likely cytotoxic effects of elevated concentrations of intracellular Ca(2+) arising from these effects may underlie some of the endocrine disrupting potential of these widespread industrial pollutants.
Collapse
Affiliation(s)
- Christopher J Kirk
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT Birmingham, UK.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Lalah JO, Schramm KW, Severin GF, Lenoir D, Henkelmann B, Behechti A, Guenther K, Kettrup A. In vivo metabolism and organ distribution of a branched 14C-nonylphenol isomer in pond snails, Lymnaea stagnalis L. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2003; 62:305-319. [PMID: 12595170 DOI: 10.1016/s0166-445x(02)00106-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The branched isomers of p-nonylphenol (NP) are perceived to be more resistant to biodegradation in aquatic environments as well as to have more estrogen-like toxicity than the straight chain isomers. By use of GC-MS, some of them have been identified and found to exist in higher concentrations in the isomeric compound mixture than the straight chain isomers. The investigations of the distribution and metabolism of these branched isomers in aquatic organisms are therefore considered to be important in understanding the mechanisms of toxicity of NP. A single tertiary isomer of NP, 4(3'-,6'-dimethyl-3'-heptyl)-phenol, was synthesized in the laboratory and used in in vivo studies of its organ distribution and metabolism in Lymnaea stagnalis L., following a constant exposure of the organisms to 14C-NP isomer in water over a period of 8 days at an average exposure concentration of 105 ppb (range: 93-116 ppb). The results obtained clearly showed the distribution and bioconcentration of the isomer residues in various internal organs of Lymnaea after uptake in water and food. Analysis of the extracts of the organ tissues and faeces by HPLC and GC-MS after digestion with Pankreatin/beta-glucuronidase and nitric acid, respectively, showed that the isomer was metabolized by conjugation to glucuronic acid and hydroxylation to a catechol. The findings from these studies and their implications in the biotransformation and estrogenicity of NP in Lymnaea stagnalis L. are further discussed in detail in this paper.
Collapse
Affiliation(s)
- J O Lalah
- Institut für Okologische Chemie, GSF-Forschungszentrum für Umwelt und Gesundheit, Ingolstädter Landstrasse 1, D-85764 Neuherberg, Muenchen, Germany
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Bilmen JG, Wootton LL, Michelangeli F. The mechanism of inhibition of the sarco/endoplasmic reticulum Ca2+ ATPase by paxilline. Arch Biochem Biophys 2002; 406:55-64. [PMID: 12234490 DOI: 10.1016/s0003-9861(02)00240-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Paxilline, an indole alkaloid mycotoxin from Penicillium paxilli, is an inhibitor of the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA). Paxilline inhibited differing isoforms of SERCA with IC50s between 5 and 50 microM. It inhibited more potently the purified Ca2+ ATPase activity from skeletal muscle with an IC50 of 5 microM. Detailed effects of this inhibitor on the Ca2+ and ATP dependence upon activity indicate that it affects the high-affinity Ca2+-binding (E1) form of the ATPase. In addition, paxilline is a "competitive" inhibitor with respect to high concentrations of ATP, increasing the regulatory binding site K(m), without affecting the catalytic binding site K(m). At higher concentrations, paxilline inhibits phosphoenzyme formation from ATP and inorganic phosphate, without affecting nucleotide binding. We therefore suggest that paxilline has two effects on the Ca2+ ATPase. At lower concentrations (5-10 microM), paxilline inhibits the ATP-dependent acceleration of Ca2+ release from the phosphoenzyme and/or phosphoenzyme decay. At higher concentrations, paxilline inhibits phosphoenzyme formation.
Collapse
Affiliation(s)
- Jonathan G Bilmen
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | | | | |
Collapse
|
29
|
Bilmen JG, Wootton LL, Michelangeli F. The inhibition of the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase by macrocyclic lactones and cyclosporin A. Biochem J 2002; 366:255-63. [PMID: 12022919 PMCID: PMC1222768 DOI: 10.1042/bj20020431] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2002] [Revised: 05/09/2002] [Accepted: 05/22/2002] [Indexed: 11/17/2022]
Abstract
The pharmacology of macrocyclic lactones is varied, with many beneficial effects in treating disease processes. FK-506, rapamycin and ascomycin have been utilized as immunosuppressant agents. Ivermectin is typically used to treat parasitic worm infections in mammals. Another immunosuppressant, cyclosporin A, is a cyclic oligotide that has similar immunosuppressant properties to those exerted by macrocyclic lactones. Here we report on the inhibition by these compounds of sarcoplasmic/endoplasmic-reticulum Ca(2+)-ATPase (SERCA) Ca(2+) pumps. Ivermectin, cyclosporin A and rapamycin all inhibited the skeletal muscle sarcoplasmic reticulum Ca(2+)-ATPase (SERCA1). In addition, although ivermectin inhibited brain microsomal endoplasmic reticulum (type 2b) Ca(2+)-ATPase, cyclosporin A and rapamycin did not. As cyclosporin A also did not inhibit cardiac Ca(2+)-ATPase activity, this would suggest that it could be an isoform-specific inhibitor. Ivermectin was shown to be the most potent Ca(2+)-ATPase inhibitor of the macrocyclic lactones (IC(50)=7 microM). It appears to show a 'competitive' inhibition with respect to high concentrations of ATP by increasing the regulatory binding site K(m) but without affecting the catalytic site K(m). In addition, ivermectin stabilizes the ATPase in an E1 conformational state, and inhibits Ca(2+) release from the enzyme during turnover. This would suggest that ivermectin inhibits Ca(2+) release from the luminal binding sites of the phosphoenzyme intermediate, a step that is known to be accelerated by high [ATP].
Collapse
Affiliation(s)
- Jonathan G Bilmen
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | | | | |
Collapse
|
30
|
Bilmen JG, Wootton LL, Godfrey RE, Smart OS, Michelangeli F. Inhibition of SERCA Ca2+ pumps by 2-aminoethoxydiphenyl borate (2-APB). 2-APB reduces both Ca2+ binding and phosphoryl transfer from ATP, by interfering with the pathway leading to the Ca2+-binding sites. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:3678-87. [PMID: 12153564 DOI: 10.1046/j.1432-1033.2002.03060.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
2-Aminoethoxydiphenyl Borate (2-APB) has been extensively used recently as a membrane permeable modulator of inositol-1,4,5-trisphosphate-sensitive Ca2+ channels and store-operated Ca2+ entry. Here, we report that 2-APB is also an inhibitor of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) Ca2+ pumps, and additionally increases ion leakage across the phospholipid bilayer. Therefore, we advise caution in the interpretation of results when used in Ca2+ signalling experiments. The inhibition of 2-APB on the SERCA Ca2+ pumps is isoform-dependent, with SERCA 2B being more sensitive than SERCA 1A (IC50 values for inhibition being 325 and 725 micro m, respectively, measured at pH 7.2). The Ca2+-ATPase is also more potently inhibited at lower pH (IC50 = 70 micro m for SERCA1A at pH 6). 2-APB decreases the affinity for Ca2+ binding to the ATPase by more than 20-fold, and also inhibits phosphoryl transfer from ATP (by 35%), without inhibiting nucleotide binding. Activity studies performed using mutant Ca2+-ATPases show that Tyr837 is critical for the inhibition of activity by 2-APB. Molecular modeling studies of 2-APB binding to the Ca2+ ATPase identified two potential binding sites close to this residue, near or between transmembrane helices M3, M4, M5 and M7. The binding of 2-APB to these sites could influence the movement of the loop between M6 and M7 (L6-7), and reduce access of Ca2+ to their binding sites.
Collapse
Affiliation(s)
- Jonathan G Bilmen
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | | | | | | | | |
Collapse
|
31
|
Lax A, Soler F, Fernandez-Belda F. Inhibition of sarcoplasmic reticulum Ca2+-ATPase by miconazole. Am J Physiol Cell Physiol 2002; 283:C85-92. [PMID: 12055076 DOI: 10.1152/ajpcell.00580.2001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The inhibition of sarcoplasmic reticulum Ca2+-ATPase activity by miconazole was dependent on the concentration of ATP and membrane protein. Half-maximal inhibition was observed at 12 microM miconazole when the ATP concentration was 50 microM and the membrane protein was 0.05 mg/ml. When ATP was 1 mM, a low micromolar concentration of miconazole activated the enzyme, whereas higher concentrations inhibited it. A qualitatively similar response was observed when Ca2+ transport was measured. Likewise, the half-maximal inhibition value was higher when the membrane concentration was raised. Phosphorylation studies carried out after sample preequilibration in different experimental settings shed light on key partial reactions such as Ca2+ binding and ATP phosphorylation. The miconazole effect on Ca2+-ATPase activity can be attributed to stabilization of the Ca2+-free enzyme conformation giving rise to a decrease in the rate of the Ca2+ binding transition. The phosphoryl transfer reaction was not affected by miconazole.
Collapse
Affiliation(s)
- Antonio Lax
- Departamento de Bioquímica y Biología Molecular A, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30071 Espinardo, Murcia, Spain
| | | | | |
Collapse
|
32
|
Logan-Smith MJ, Lockyer PJ, East JM, Lee AG. Curcumin, a molecule that inhibits the Ca2+-ATPase of sarcoplasmic reticulum but increases the rate of accumulation of Ca2+. J Biol Chem 2001; 276:46905-11. [PMID: 11592968 DOI: 10.1074/jbc.m108778200] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Curcumin, an important inhibitor of carcinogenesis, is an inhibitor of the ATPase activity of the Ca(2+)-ATPase of skeletal muscle sarcoplasmic reticulum (SR). Inhibition by curcumin is structurally specific, requiring the presence of a pair of -OH groups at the 4-position of the rings. Inhibition is not competitive with ATP. Unexpectedly, addition of curcumin to SR vesicles leads to an increase in the rate of accumulation of Ca(2+), unlike other inhibitors of the Ca(2+)-ATPase that result in a reduced rate of accumulation. An increase in the rate of accumulation of Ca(2+) is seen in the presence of phosphate ion, which lowers the concentration of free Ca(2+) within the lumen of the SR, showing that the effect is not passive leak across the SR membrane. Rather, simulations suggest that the effect is to reduce the rate of slippage on the ATPase, a process in which a Ca(2+)-bound, phosphorylated intermediate releases its bound Ca(2+) on the cytoplasmic rather than on the lumenal side of the membrane. The structural specificity of the effects of curcumin on ATPase activity and on Ca(2+) accumulation is the same, and the apparent dissociation constants for the two effects are similar, suggesting that the two effects of curcumin could follow from binding to a single site on the ATPase.
Collapse
Affiliation(s)
- M J Logan-Smith
- Division of Biochemistry and Molecular Biology, School of Biological Sciences, University of Southampton, Southampton SO16 7PX, UK
| | | | | | | |
Collapse
|
33
|
Bilmen JG, Khan SZ, Javed MH, Michelangeli F. Inhibition of the SERCA Ca2+ pumps by curcumin. Curcumin putatively stabilizes the interaction between the nucleotide-binding and phosphorylation domains in the absence of ATP. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:6318-27. [PMID: 11733029 DOI: 10.1046/j.0014-2956.2001.02589.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Curcumin is a compound derived from the spice, tumeric. It is a potent inhibitor of the SERCA Ca2+ pumps (all isoforms), inhibiting Ca2+-dependent ATPase activity with IC50 values of between 7 and 15 microm. It also inhibits ATP-dependent Ca2+-uptake in a variety of microsomal membranes, although for cerebellar and platelet microsomes, a stimulation in Ca2+ uptake is observed at low curcumin concentrations (<10 microm). For the skeletal muscle isoform of the Ca2+ pump (SERCA1), the inhibition of curcumin is noncompetitive with respect to Ca2+, and competitive with respect to ATP at high curcumin concentrations ( approximately 10-25 microm). This was confirmed by ATP binding studies that showed inhibition in the presence of curcumin: ATP-dependent phosphorylation was also reduced. Experiments with fluorescein 5'-isothiocyanate (FITC)-labelled ATPase also suggest that curcumin stabilizes the E1 conformational state. The fact that FITC labels the nucleotide binding site of the ATPase (precluding ATP from binding), and the fact that curcumin affects FITC fluorescence indicate that curcumin must be binding to another site within the ATPase that induces a conformational change to prevent ATP from binding. This observation is interpreted, with the aid of recent structural information, as curcumin stabilizing the interaction between the nucleotide-binding and phosphorylation domains, precluding ATP binding.
Collapse
Affiliation(s)
- J G Bilmen
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | | | | | | |
Collapse
|
34
|
Latendresse JR, Newbold RR, Weis CC, Delclos KB. Polycystic kidney disease induced in F(1) Sprague-Dawley rats fed para-nonylphenol in a soy-free, casein-containing diet. Toxicol Sci 2001; 62:140-7. [PMID: 11399801 DOI: 10.1093/toxsci/62.1.140] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
para-Nonylphenol (NP; CAS #84852-15-3), an alkylphenol with a 9-carbon olefin side chain, is widely used in the manufacture of nonionic surfactants, lubricant additives, polymer stabilizers, and antioxidants. Due to its wide commercial use and putative endocrine activity in humans and wildlife, the NTP elected to assess its effects on reproduction in multigenerational studies. To avoid known estrogenic activity of phytoestrogens in soy and alfalfa, a soy- and alfalfa-free, casein-containing diet was used in a range-finding study to determine the doses of NP to be tested further. NP was administered to Sprague-Dawley rats in the diet at 0, 5, 25, 200, 500, 1000, or 2000 ppm to F(0) dams beginning on gestation-day 7. The F(1) pups were weaned at postnatal day (PND) 21, and their exposure via diet was continued at the same dose level as their respective dams. Pup weights from birth through weaning were not significantly different from controls in any dose group, but the average weight of both sexes was significantly less compared to controls, beginning with the PND 28 weighing. The F(1) rats were sacrificed on PND 50 (n = 15, 3 pups of each sex from 5 litters for all dose groups). Terminal body weights of males and females in the 2000-ppm dose group were 74% and 85% of controls, respectively. Severe polycystic kidney disease (PKD) was present in 100% of the 2000 ppm-exposed male and female rats. At 1000 ppm, 67% of males and 53% of females had mild to moderate PKD versus none of either sex in the control and lower-dose groups. The no-adverse-effect level (NOAEL) for PKD was determined to be 500 ppm. Previous studies with comparable duration and route of exposure, but using soy-containing diets, reported either no or only mild PKD at 2000 ppm NP. We conclude that the renal toxicity of NP is highly dependent on the diet on which the animals are maintained. The potential interaction of diet and test compounds on nonreproductive as well as reproductive endpoints should be considered when contemplating the use of special diets formulated to minimize exogenous "hormone" content for the study of the effects of putative endocrine disruptive chemicals.
Collapse
Affiliation(s)
- J R Latendresse
- Pathology Associates International, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA.
| | | | | | | |
Collapse
|
35
|
Milani G, Schereiber AZ, Vercesi AE. Ca(2+) transport into an intracellular acidic compartment of Candida parapsilosis. FEBS Lett 2001; 500:80-4. [PMID: 11434931 DOI: 10.1016/s0014-5793(01)02585-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this report, we study Ca2+ transport in permeabilized Candida parapsilosis spheroplasts prepared by a new technique using lyticase. An intracellular non-mitochondrial Ca2+ uptake pathway, insensitive to orthovanadate and sensitive to the V-H(+)-ATPase inhibitor bafilomycin A(1), nigericin and carbonyl cyanide p-trifluoromethoxyphenylhydrazone was characterized. Acidification of the compartment in which Ca2+ accumulated was followed using the fluorescent dye acridine orange. Acidification was stimulated by the Ca2+ chelator EGTA and inhibited by Ca2+. These results, when added to the observation that Ca2+ induces alkalization of a cellular compartment, provide evidence for the presence of a Ca2+/nH(+) antiporter in the acid compartment membrane. Interestingly, like in acidocalcisomes of trypanosomatids, the antioxidant 3,5-dibutyl-4-hydroxytoluene inhibits the V-H(+)-ATPase. In addition, the antifungal agent ketoconazole promoted a fast alkalization of the acidic compartment. Ketoconazole effects were dose-dependent and occurred in a concentration range close to that attained in the plasma of patients treated with this drug.
Collapse
Affiliation(s)
- G Milani
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas 13083 970, SP, Brazil
| | | | | |
Collapse
|
36
|
Khan SZ, Longland CL, Michelangeli F. The effects of phenothiazines and other calmodulin antagonists on the sarcoplasmic and endoplasmic reticulum Ca(2+) pumps. Biochem Pharmacol 2000; 60:1797-806. [PMID: 11108794 DOI: 10.1016/s0006-2952(00)00505-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The effects of a number of phenothiazines and other calmodulin antagonists on the Ca(2+)-ATPase activity of sarcoplasmic reticulum (SR) and endoplasmic reticulum (ER) were investigated. The drugs used in this study were trifluoperazine, calmidazolium, fluphenazine, chlorpromazine, W-7, and calmodulin-binding peptide. Our results showed that calmidazolium and calmodulin-binding peptide were the most potent inhibitors of skeletal muscle SR Ca(2+)-ATPase activity (isoform SERCA 1) (IC(50) values of 0.5 and 7 microM, respectively), while W-7 was the least potent inhibitor (IC(50), 125 microM). All of the antagonists had little effect on the cerebellar ER Ca(2+)-ATPase activity (isoform SERCA 2b), except for trifluoperazine, which had a biphasic effect, causing stimulation at low concentrations and inhibition at higher concentrations. Our results suggest that the effects of these calmodulin antagonists are independent of calmodulin and that they inhibit the Ca(2+)-ATPase in an isoform-specific manner. It was found that these antagonists inhibit the skeletal muscle isoform of the Ca(2+) pump by altering the Ca(2+) affinity and the associated Ca(2+)-binding steps, as well as possibly stabilising the E1 conformational state of the enzyme.
Collapse
Affiliation(s)
- S Z Khan
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, Birmingham, UK
| | | | | |
Collapse
|
37
|
Hughes PJ, McLellan H, Lowes DA, Kahn SZ, Bilmen JG, Tovey SC, Godfrey RE, Michell RH, Kirk CJ, Michelangeli F. Estrogenic alkylphenols induce cell death by inhibiting testis endoplasmic reticulum Ca(2+) pumps. Biochem Biophys Res Commun 2000; 277:568-74. [PMID: 11061995 DOI: 10.1006/bbrc.2000.3710] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Industrial alkylphenols in the environment may act as "xenoestrogens" to disrupt testicular development and decrease male fertility. Amongst possible targets for these compounds are testicular Sertoli cells, which nurture the developing sperm cells. We demonstrate that SERCA 2 and 3 Ca(2+) pumps are relatively abundant in rat testis microsomal membranes, and also in Sertoli, myoid, and TM4 cells (a Sertoli cell line). A number of estrogenic alkylphenols such as nonylphenol, octylphenol, bisphenol A, and butylated hydroxytoluene all inhibit testicular Ca(2+) ATPase in the low micromolar concentration range. These agents also mobilize intracellular Ca(2+) in intact TM4 cells in a manner consistent with the inhibition of ER Ca(2+) pumps. Alkylphenols dramatically decrease the viability of TM4 cells, an effect that is reversed by either a caspase inhibitor or by BAPTA, and is therefore consistent with Ca(2+)-dependent cell death via apoptosis. We postulate that alkylphenols disrupt testicular development by inhibiting ER Ca(2+) pumps, thus disturbing testicular Ca(2+) homeostasis.
Collapse
Affiliation(s)
- P J Hughes
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Schwaiger J, Spieser OH, Bauer C, Ferling H, Mallow U, Kalbfus W, Negele RD. Chronic toxicity of nonylphenol and ethinylestradiol: haematological and histopathological effects in juvenile Common carp (Cyprinus carpio). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2000; 51:69-78. [PMID: 10998500 DOI: 10.1016/s0166-445x(00)00098-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In recent ecotoxicological research, there is an increasing concern about alkylphenolic industrial chemicals, such as nonylphenol (NP), because of their estrogenic properties. Data on the general fish toxicity of these wide spread aquatic pollutants are scarce. In order to evaluate sublethal toxic effects of environmentally relevant concentrations of NP, juvenile Common carp (Cyprinus carpio) were exposed to NP concentrations ranging from 1 to 15 microg NP/l over a 70-day period. Classical toxicological endpoints, such as various haematological parameters and histopathological alterations were investigated. In a comprehensive protocol, besides NP-induced effects also alterations due to a treatment with the synthetic estrogen ethinylestradiol (EE2) were evaluated. After both the NP-exposure as well as the EE2-treatment, the predominant haematological finding was a severe anaemia. Histopathological alterations in the kidney, the liver and the spleen occurred exclusively after treatment with EE2, whereas NP-exposed fish did not show any tissue lesions. Depending on the haematological parameter examined, a NOEC between 1 and 5 microg NP/l could be established. From the present findings, it is assumed, that under field conditions, the NP-induced, general toxic effects, might outbalance the relatively weak estrogenic effects of this compound and possibly might disturb ecologically relevant processes such as fish reproduction.
Collapse
Affiliation(s)
- J Schwaiger
- Bavarian State Office of Water Management, Institute for Water Research, Demollstr. 31, 82407, Wielenbach, Germany.
| | | | | | | | | | | | | |
Collapse
|
39
|
Lamche G, Burkhardt-Holm P. Nonylphenol provokes a vesiculation of the Golgi apparatus in three fish epidermis cultures. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2000; 47:137-148. [PMID: 11023692 DOI: 10.1006/eesa.2000.1957] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The aim of this work was to study the effects of nonylphenol and waste water on the cell ultrastructure of fish skin. Therefore, besides a recently established primary cell culture and a cell line, an epidermal tissue culture of fish was developed and tested. In all three systems a prominent vesiculation of the Golgi apparatus was observed after exposure to nonylphenol, which has not been described before and therefore strongly suggests an effect that might indicate exposure to nonylphenol and/or related substances. The Epithelial papulosum cyprini cell line was the most sensitive to nonylphenol, followed by the primary cell culture of epidermis cells and then the explant tissue culture. The vesiculation of the Golgi apparatus was accompanied by degenerative changes in the two cell cultures only. The lack of degenerative changes in the cells of the tissue culture was discussed with respect to the presence of differentiated cells that might better be able to protect themselves by mucous or by an activated xenobiotic metabolism. In a second type experiment, a waste water sample containing small concentrations of nonylphenol was applied to the cultures. It did not lead to a vesiculation of the Golgi apparatus, probably because the nonylphenol concentrations in the waste water were too low to induce the vesiculation. The cultures exposed to waste water revealed unspecific degenerative cellular changes. Additionally, explant cultures were prepared from fish that had survived a 6-month exposure to polluted river water. In these cultures a higher number of mitochondria containing myelin bodies were observed when compared to control cultures. Consequently, exposure to polluted water containing a mixture of substances in vitro and in vivo was found to lead to degenerative alterations in the ultrastructure of the cells.
Collapse
Affiliation(s)
- G Lamche
- Centre for Fish and Wildlife Health, Institute of Animal Pathology, Laenggassstrasse 122, Bern, CH-3012, Switzerland
| | | |
Collapse
|
40
|
Okai Y, Higashi-Okai K, Machida K, Nakamura H, Nakayama K, Fijita K, Tanaka T, Taniguchi M. Protective effects of alpha-tocopherol and beta-carotene on para-nonylphenol-induced inhibition of cell growth, cellular respiration and glucose-induced proton extrusion of bacteria. FEMS Microbiol Lett 2000; 187:161-5. [PMID: 10856651 DOI: 10.1111/j.1574-6968.2000.tb09154.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
para-Nonylphenol (NP) showed a dose-dependent inhibition against the cell growth of Bacillus subtilis, Micrococcus luteus, Pseudomonas aeruginosa and Staphylococcus aureus at 5-100 microM. However, other typical plastic-derived endocrine disruptors such as bisphenol A and di-2-ethylhexyl phthalate (DEHP) did not significantly affect the cell growth of these bacteria at 5-100 microM. The NP-induced cell growth inhibition was restored when concomitantly supplemented with lipophilic antioxidants such as alpha-tocopherol and beta-carotene, but not with hydrophilic antioxidants, ascorbic acid and (-)-epigallocatechin gallate (EGCG). NP also suppressed in a dose-dependent manner cellular oxygen consumption and glucose-induced proton extrusion of these bacteria at 10-100 microM. Both effects were prevented when added with alpha-tocopherol and beta-carotene, but not with ascorbic acid and EGCG. The significance of these results is discussed from the viewpoint of environmental microbiology and a possible biochemical mechanism of the inhibitory effect of NP is suggested.
Collapse
Affiliation(s)
- Y Okai
- Department of Human Life Science, Osaka Kun-Ei Women's College, Set's City, Japan
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Vercesi AE, Rodrigues CO, Catisti R, Docampo R. Presence of a Na(+)/H(+) exchanger in acidocalcisomes of Leishmania donovani and their alkalization by anti-leishmanial drugs. FEBS Lett 2000; 473:203-6. [PMID: 10812075 DOI: 10.1016/s0014-5793(00)01531-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Acidocalcisomes are acidic vacuoles present in trypanosomatids that contain most of the cellular calcium. The data presented here demonstrate that Leishmania donovani acidocalcisomes possess a Na(+)/H(+) exchanger. 3,5-Dibutyl-4-hydroxytoluene, in the concentration range of 0-20 microM, inhibited the Na(+)/H(+) exchanger, and strongly stimulated the activity of the vacuolar H(+)-ATPase responsible for vacuolar acidification. As occurs with Na(+), the cationic anti-leishmanial drugs pentamidine, WR-6026, and chloroquine promoted a fast and extensive alkalization of the L. donovani acidocalcisomes.
Collapse
Affiliation(s)
- A E Vercesi
- Laboratory of Molecular Parasitology, Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 S. Lincoln Avenue, Urbana, IL, USA
| | | | | | | |
Collapse
|
42
|
Burkhardt-Holm P, Wahli T, Meier W. Nonylphenol affects the granulation pattern of epidermal mucous cells in rainbow trout, Oncorhynchus mykiss. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2000; 46:34-40. [PMID: 10805991 DOI: 10.1006/eesa.1999.1871] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Nonylphenol is a biodegradation product of nonionic surfactants and has recently attracted considerable attention due to its estrogenic potential. Sexually mature male rainbow trout were repeatedly exposed (one to four periods of 10 days each) to environmentally relevant concentrations of nonylphenol (1 microg/L, 10 microg/L) and for comparison, trout were injected with estradiol. Since estrogens are known to induce structural changes within the fish skin, a similar effect of xenobiotics with estrogen-like activity was assumed. Samples of skin were evaluated by means of light and electron microscopy and histochemistry. In trout exposed to nonylphenol and to estradiol, the structure of the epidermis was altered: an irregular overall architecture was often accompanied by detached pavement cells, vacuolation of the cytoplasm, and severely deformed cell nuclei. However, the granulation pattern of the mucous cells was influenced exclusively after exposition to nonylphenol. The number of large and irregularly shaped mucosomes depended more on the exposure period than on the concentration of nonylphenol. Furthermore, this alteration has not yet been reported for any other pollutant or stressor and, thus, can be classified as an effect that would strongly indicate exposure to nonylphenol.
Collapse
Affiliation(s)
- P Burkhardt-Holm
- Swiss Federal Institute for Environmental Science and Technology, EAWAG, Dubendorf, CH-8600, Switzerland
| | | | | |
Collapse
|
43
|
Okai Y, Higashi-Okai K, Machida K, Nakamura H, Nakayama K, Fujita K, Tanaka T, Otani S, Taniguchi M. Protective effect of antioxidants against para-nonylphenol-induced inhibition of cell growth in Saccharomyces cerevisiae. FEMS Microbiol Lett 2000; 185:65-70. [PMID: 10731608 DOI: 10.1111/j.1574-6968.2000.tb09041.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The cell growth-modulating activity of an endocrine disruptor, p-nonylphenol (NP), was estimated using the yeast Saccharomyces cerevisiae as a simple model of eukaryotic cells. NP caused a dose-dependent suppressive effect on cell growth of S. cerevisiae at 10, 25 and 50 microM. The NP-induced cell growth inhibition was restored when concomitantly lipophilic antioxidants such as alpha-tocopherol and beta-carotene were supplied, but not the hydrophilic antioxidants ascorbic acid or (-)epigallocatechin gallate (EGCG). The cellular oxygen consumption of S. cerevisiae was also inhibited in a dose-dependent fashion by the extracellular addition of NP, and pretreatment with alpha-tocopherol and beta-carotene suppressed NP-induced inhibition of cellular oxygen consumption, but ascorbic acid and EGCG were not effective. Furthermore, NP caused a marked generation of radical oxygen species (ROS) in S. cerevisiae, which was suppressed by treatment with alpha-tocopherol and beta-carotene, but not with ascorbic acid and EGCG. However, NP did not show a significant inhibitory effect on cell growth and survival of mitochondria-deficient petite mutant cells and they showed a relatively weak ROS-generating activity compared with parent yeast cells. These results suggest that NP-induced inhibition of cell growth and oxygen consumption in S. cerevisiae might be possibly associated with ROS generation in yeast mitochondria. The significance of this finding is discussed from the viewpoint of NP-induced oxidative stress against eukaryotic cells.
Collapse
Affiliation(s)
- Y Okai
- Department of Human Life Science, Osaka Kun-Ei Women's College, Showjaku, Set's City, Osaka, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Soler F, Plenge-Tellechea F, Fortea I, Fernandez-Belda F. Clomipramine and related structures as inhibitors of the skeletal sarcoplasmic reticulum Ca2+ pump. J Bioenerg Biomembr 2000; 32:133-42. [PMID: 11768746 DOI: 10.1023/a:1005519312463] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The Ca2+-pumping activity of skeletal sarcoplasmic reticulum vesicles is half-maximally inhibited by 120 microM clomipramine, 250 microM desipramine, and 500 microM imipramine or trimipramine. The inhibition is attributed to the dihydrodibenzazepine moiety, since 3-(dimethylamino)propionitrile, reproducing the aliphatic amine chain, has no inhibitory action. The inhibition is shown as a marked decrease of Ca2+ binding at equilibrium in the absence of ATP and as a reduction of phosphorylation of the Ca2+-free conformation by inorganic phosphate. Therefore, the drug effect is consistent with preferential interaction of tricyclic antidepressants with the Ca2+-free conformation of the nonphosphorylated enzyme. An additional decrease in the apparent rate constant of enzyme dephosphorylation, i.e., in the release of phosphate from ATP during enzyme cycling was also noticed.
Collapse
Affiliation(s)
- F Soler
- Departamento de Bioquimica y Biologia Molecular A, Facultad de Veterinaria, Universidad de Murcia en Espinardo, Spain
| | | | | | | |
Collapse
|
45
|
Bhattacharyya D, Sen PC. The effect of binding of chlorpromazine and chloroquine to ion transporting ATPases. Mol Cell Biochem 1999; 198:179-85. [PMID: 10497894 DOI: 10.1023/a:1006902031255] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The inhibition of ion transporting ATPases (Na+,K+-ATPase, Ca2+,Mg2+- and Ca2+-ATPase) by two amphiphilic drugs e.g. chlorpromazine (antipsychotic) and chloroquine (antimalarial) are found to be competitive in nature in vitro with respect to the substrate. Two binding sites - high and low affinity are found to exist on all the three ATPases toward these drugs as evident from the plot of F/F0 vs. different drug concentrations of tryptophan fluorescence of the enzymes. Circular dichroism analysis suggest that binding of drugs to the high affinity site does not involve any change in conformation of ATPase molecules which occur only when drug binds to the low affinity sites. The drug binding sites and possible effect on conformational change of ATPase molecules of these two drugs have been described in this report.
Collapse
|
46
|
Barata H, Cardoso CM, Wolosker H, de Meis L. Modulation of the low affinity Ca2+-binding sites of skeletal muscle and blood platelets Ca2+-ATPase by nordihydroguaiaretic acid. Mol Cell Biochem 1999; 195:227-33. [PMID: 10395087 DOI: 10.1023/a:1006953126740] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The antioxidant nordihydroguaiaretic acid (NDGA) inhibited the different sarco/endoplasmic reticulum Ca2+-ATPase isoforms found in skeletal muscle and blood platelets. For the sarcoplasmic reticulum, but not for the blood platelets Ca2+-ATPase, the concentration of NDGA needed for half-maximal inhibition was found to vary depending on the substrate used and its concentration in the assay medium. The phosphorylation of the sarcoplasmic reticulum Ca2+-ATPase by ATP and by Pi were both inhibited by NDGA. In leaky vesicles, measurements of the ATP<-->Pi exchange showed that NDGA increases the affinity for Ca2+ of the E2 conformation of the enzyme, which has low affinity for Ca2+. The effects of NDGA on the Ca2+-ATPase were not reverted by the reducing agent dithiothreitol nor by the lipid-soluble antioxidant butylated hydroxytoluene.
Collapse
Affiliation(s)
- H Barata
- Instituto de Ciências Biomédicas, Departamento de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Cidade Universitária, Brazil
| | | | | | | |
Collapse
|
47
|
|
48
|
Vercesi AE, Grijalba MT, Docampo R. Inhibition of Ca2+ release from Trypanosoma brucei acidocalcisomes by 3,5-dibutyl-4-hydroxytoluene: role of the Na+/H+ exchanger. Biochem J 1997; 328 ( Pt 2):479-82. [PMID: 9371704 PMCID: PMC1218944 DOI: 10.1042/bj3280479] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Acidocalcisomes are acidic vacuoles present in trypanosomatids that contain a considerable fraction of intracellular Ca2+. They possess a vacuolar-type H+-ATPase for H+ uptake, a Ca2+/H+ countertransporting ATPase for Ca2+ uptake and a Ca2+/nH+ antiporter for Ca2+ release. Trypanosoma brucei procyclic trypomastigotes acidocalcisomes possess, in addition, an Na+/H+ antiporter that may participate in Ca2+ release from these organelles. In this work we show that the hydrophobic antioxidant 3,5-dibutyl-4-hydroxy toluene (BHT), at concentrations in the range 1-20 microM, inhibits Na+-induced Ca2+ release from the acidocalcisomes of digitonin-permeabilized procyclic trypomastigotes in a concentration-dependent manner. This effect supports the notion that Ca2+ release from this compartment is regulated by the activity of the Na+/H+ antiporter. In the presence of BHT, Ca2+ release could still be obtained by nigericin-mediated alkalinization of the acidocalcisomes, clearly demonstrating that the action of BHT is not at the level of the Ca2+/nH+ antiporter but on that of the Na+/H+ antiporter. In the same range of concentrations and depending on the preincubation time, BHT had an stimulatory or an inhibitory effect on the vacuolar H+-ATPase present in T. brucei acidocalcisomes. Since these effects of BHT were obtained at concentrations which are commonly used for its antioxidant properties, these results indicate that care should be exercised when attributing effects of BHT to only these properties.
Collapse
Affiliation(s)
- A E Vercesi
- Laboratory of Molecular Parasitology, Department of Pathobiology, College of Veterinary Medicine, University of Illinois, 2001 S. Lincoln Ave, Urbana, IL 61802, USA
| | | | | |
Collapse
|
49
|
Sorensen T, Vilsen B, Andersen JP. Mutation Lys758 --> Ile of the sarcoplasmic reticulum Ca2+-ATPase enhances dephosphorylation of E2P and inhibits the E2 to E1Ca2 transition. J Biol Chem 1997; 272:30244-53. [PMID: 9374509 DOI: 10.1074/jbc.272.48.30244] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The highly conserved lysine residue Lys758 in the fifth stalk segment of the sarcoplasmic reticulum Ca2+-ATPase was substituted with either isoleucine or arginine by site-directed mutagenesis. The substitution with arginine was without significant effects on Ca2+-ATPase function, whereas multiple changes of functional characteristics were observed with the Lys758 --> Ile mutant. These included insensitivity of ATPase activity to the calcium ionophore A23187, an alkaline shift of the pH dependence of ATPase activity, reduced maximum molecular turnover rate and steady-state phosphorylation level, reduced apparent affinities for Ca2+ and inorganic phosphate, as well as increased sensitivity to inhibition by vanadate. Analysis of the partial reaction steps of the enzyme cycle traced these changes to two steps. The rate of dephosphorylation of the ADP-insensitive phosphoenzyme intermediate (E2P) was increased, irrespective of variations of pH, K+, Ca2+, and dimethyl sulfoxide concentration. In addition, the rate of conversion of the dephosphoenzyme with low Ca2+ affinity (E2) to the Ca2+-bound form activated for phosphorylation (E1Ca2) was reduced in the mutant, and the ATP-induced rate enhancement of this step required higher ATP concentrations in the mutant compared with the wild type.
Collapse
Affiliation(s)
- T Sorensen
- Department of Physiology, University of Aarhus, DK-8000 Aarhus C, Denmark.
| | | | | |
Collapse
|
50
|
Lahouratate P, Guibert J, Camelin JC, Bertrand I. Specific inhibition of cardiac and skeletal muscle sarcoplasmic reticulum Ca2+ pumps by H-89. Biochem Pharmacol 1997; 54:991-8. [PMID: 9374419 DOI: 10.1016/s0006-2952(97)00320-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The isoquinolinesulfonamide H-89, an inhibitor of cyclic AMP-dependent protein kinases (EC 2.7.1.37, cAPrK), inhibited the Ca2+-ATPase activity of cardiac and skeletal muscle sarcoplasmic reticulum (SR) with concentrations giving half-maximal inhibition of 8.1 +/- 1.3 and 7.2 +/- 0.9 micromol/L, respectively. The effect of H-89 on cardiac SR Ca2+-ATPase (EC 3.6.1.38) was the same irrespective of the presence or absence of inhibitors of cAPrK and furthermore, was not affected by a neutralising monoclonal antibody raised against phospholamban. Thus, the action of H-89 in inhibiting SR Ca2+-ATPase would not appear to be mediated by inhibition of cAPrK to reduce the phosphorylation state of phospholamban. In both cardiac and skeletal muscle SR, the inhibition by H-89 was noncompetitive with respect to ATP at a low concentration of ATP (<1 mmol/L) and of a mixed pattern at high concentrations of ATP. H-89 produced a decrease in affinity of the SR Ca2+ pump to Ca2+ with an increase in the Km for Ca from 0.52 +/- 0.01 to 0.94 +/- 0.03 micromol/L (P < 0.05) in cardiac SR and from 0.39 +/- 0.01 to 0.79 +/- 0.02 micromol/L (P < 0.05) in skeletal muscle SR. These results suggest that H-89 inhibits SR Ca2+-ATPase by a direct action on the SR Ca2+ pump to decrease its affinity to Ca2+. Such an action may contribute to the pharmacological effect of H-89.
Collapse
Affiliation(s)
- P Lahouratate
- SmithKline Beecham Laboratoires Pharmaceutiques, Sainte-Grégoire, France
| | | | | | | |
Collapse
|