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Lu LL, Zhang YW, Li ZC, Fang YY, Wang LL, Zhao YS, Li SJ, Ou SY, Aschner M, Jiang YM. Therapeutic Effects of Sodium Para-Aminosalicylic Acid on Cognitive Deficits and Activated ERK1/2-p90 RSK/NF-κB Inflammatory Pathway in Pb-Exposed Rats. Biol Trace Elem Res 2022; 200:2807-2815. [PMID: 34398420 DOI: 10.1007/s12011-021-02874-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/08/2021] [Indexed: 12/25/2022]
Abstract
Lead (Pb) is a toxic heavy metal and environmental pollutant that adversely affects the nervous system. However, effective therapeutic drugs for Pb-induced neurotoxicity have yet to be developed. In the present study, we investigated the ameliorative effect of sodium para-aminosalicylic acid (PAS-Na) on Pb-induced neurotoxicity. Male Sprague-Dawley rats were treated with (CH3COO)2 Pb•4H2O (6 mg/kg) for 4 weeks, followed by 3 weeks of PAS-Na (100, 200, and 300 mg/kg). The results showed that subacute Pb exposure significantly decreased rats body-weight gains and increased liver coefficient, and impaired spatial learning and memory. HE staining showed that Pb damaged the structure of the hippocampus. Moreover, Pb activated the ERK1/2-p90RSK/ NF-κB pathway concomitant with increased inflammatory cytokine IL-1β levels in rat hippocampus. PAS-Na reversed the Pb-induced increase in the liver coefficient as well as the learning and memory deficits. In addition, PAS-Na reduced the phosphorylation of ERK1/2, p90RSK and NF-κB p65, decreasing IL-1β levels in hippocampus. Our findings indicated that PAS-Na showed efficacy in reversing Pb-induced rats cognitive deficits and triggered an anti-inflammatory response. Thus, PAS-Na may be a promising therapy for treating Pb-induced neurotoxicity.
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Affiliation(s)
- Li-Li Lu
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, 530021, China
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Yu-Wen Zhang
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, 530021, China
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Zhao-Cong Li
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, 530021, China
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Yuan-Yuan Fang
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, 530021, China
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Lei-Lei Wang
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, 530021, China
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Yue-Song Zhao
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, 530021, China
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Shao-Jun Li
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, 530021, China
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Shi-Yan Ou
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, 530021, China
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Yue-Ming Jiang
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, 530021, China.
- Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China.
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Abstract
Lead is a health hazard for all humans. Especially children under the age of six are most at risk for lead poisoning. Lead toxicity causes hematological, gastrointestinal, and neurological dysfunction. Symptoms are usually noted with blood lead greater than 2 micromoles/L. Severe or prolonged exposure may also cause chronic nephropathy, hypertension, and reproductive impairment. Lead inhibits some enzymes, alters cellular calcium metabolism, stimulates synthesis of binding proteins in kidney, brain, and bone, and slows down nerve conduction. Acute lead poisoning is relatively infrequent and results from ingestion of acid soluble lead compounds or inhalation of lead vapors but chronic exposure to low levels of the metal is still a public health issue, especially among some minorities and socioeconomically disadvantaged groups. Lead has been used since prehistoric times, and has become widely distributed and mobilized in the environment. Exposure to and uptake of this non-essential element have consequently increased. Both occupational and environmental exposures to lead remain a serious problem in many developing and industrializing countries and a public health problem of global dimensions.
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Liu CM, Yang W, Ma JQ, Yang HX, Feng ZJ, Sun JM, Cheng C, Jiang H. Dihydromyricetin Inhibits Lead-Induced Cognitive Impairments and Inflammation by the Adenosine 5'-Monophosphate-Activated Protein Kinase Pathway in Mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:7975-7982. [PMID: 29975840 DOI: 10.1021/acs.jafc.8b02433] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dihydromyricetin (DHM), a natural flavonoid derived from the medicinal and edible plant Ampelopsis grossedentata, exhibits antioxidant, antiapoptosis, antitumor, and anti-inflammatory bioactivities. This study evaluated the effects of DHM on Pb-induced neurotoxicity and explored the underlying mechanisms. DHM significantly ameliorated behavioral impairments of Pb-induced mice. It decreased the levels of lipid peroxidation and protein carbonyl and increased the activities of superoxide dismutase and catalase in the brains. DHM suppressed Pb-induced apoptosis, as indicated by the decreased levels of Bax and cleaved caspase-3. DHM also decreased inflammatory cytokines in the brains of Pb-treated mice. DHM decreased amyloid-beta (Aβ) level and nuclear factor-κB nuclear translocation. Moreover, DHM induced the adenosine 5'-monophosphate-activated protein kinase (AMPK) phosphorylation and inhibited the activation of p38, Toll-like receptor 4, myeloid differentiation factor 88, and glycogen synthase kinase-3. Collectively, this is the first report indicating that DHM could improve Pb-induced cognitive functional impairment by preventing oxidative stress, apoptosis, and inflammation and that the protective effect was mediated partly through the AMPK pathway.
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Affiliation(s)
- Chan-Min Liu
- School of Life Science , Jiangsu Normal University , No.101, Shanghai Road , Tangshan New Area, 221116 , Xuzhou City , Jiangsu Province , PR China
| | - Wei Yang
- School of Life Science , Jiangsu Normal University , No.101, Shanghai Road , Tangshan New Area, 221116 , Xuzhou City , Jiangsu Province , PR China
| | - Jie-Qiong Ma
- School of Chemistry and Pharmaceutica Engineering , Sichuan University of Science and Engineering , Xuyuan road , 643000 , Zigong City , Sichuan Province , PR China
| | - Hui-Xin Yang
- School of Life Science , Jiangsu Normal University , No.101, Shanghai Road , Tangshan New Area, 221116 , Xuzhou City , Jiangsu Province , PR China
| | - Zhao-Jun Feng
- School of Life Science , Jiangsu Normal University , No.101, Shanghai Road , Tangshan New Area, 221116 , Xuzhou City , Jiangsu Province , PR China
| | - Jian-Mei Sun
- School of Life Science , Jiangsu Normal University , No.101, Shanghai Road , Tangshan New Area, 221116 , Xuzhou City , Jiangsu Province , PR China
| | - Chao Cheng
- School of Life Science , Jiangsu Normal University , No.101, Shanghai Road , Tangshan New Area, 221116 , Xuzhou City , Jiangsu Province , PR China
| | - Hong Jiang
- School of Life Science , Jiangsu Normal University , No.101, Shanghai Road , Tangshan New Area, 221116 , Xuzhou City , Jiangsu Province , PR China
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Kasten-Jolly J, Lawrence DA. The cationic (calcium and lead) and enzyme conundrum. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2018; 21:400-413. [PMID: 30917763 DOI: 10.1080/10937404.2019.1592728] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The environmental toxicant lead (Pb) and the essential element calcium (Ca) play an interactive role in extracellular and intracellular regulatory functions that affect health. Lead's usurping calcium binding sites, as well as its interactions with thiols and phosphates have been suggested to be the basis for adverse effects on many organ systems especially the nervous system. Among regulatory processes controlled by Ca are calmodulin-dependent phosphodiesterase, calmodulin-dependent protein kinases, calmodulin inhibitor sensitive potassium channels, and calmodulin-independent protein kinase C (PKC) activation. This review focused on Pb studies describing the modulation of PKC, which is also regulated by steroids. Steroid hormone regulation may relate to a focal point for the sex differences of Pb and cellular signaling events. Picomolar concentrations of Pb may stimulate partially purified PKC, but higher concentrations inhibit activity. Although knowledge exists regarding Pb and PKC isoforms, especially interaction of Pb with the purified enzyme, there are conflicting reports concerning metal-mediated activation or inhibition of PKC and downstream signaling events. The effect of Pb on PKC in vivo remains elusive. Most reports of Pb and PKC in whole animal and human studies indicated that Pb either inhibits PKC or exerts no significant effect. However, most of the animal studies were performed with males. Recent studies performed with females and males separately revealed that females and males respond to Pb quite differently, and for this reason, it is suggested that future Pb studies of PKC and other biomedical investigations be performed with females and males.
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Affiliation(s)
- Jane Kasten-Jolly
- a New York State Department of Health , Wadsworth Center , Albany , NY , USA
| | - David A Lawrence
- a New York State Department of Health , Wadsworth Center , Albany , NY , USA
- b Department of Environmental Health Sciences , University at Albany School of Public Health , Rensselaer , NY , USA
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Slaby S, Hanotel J, Marchand G, Lescuyer A, Bodart JF, Leprêtre A, Lemière S, Marin M. Maturation of Xenopus laevis oocytes under cadmium and lead exposures: Cell biology investigations. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2017; 193:105-110. [PMID: 29053961 DOI: 10.1016/j.aquatox.2017.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/25/2017] [Accepted: 10/14/2017] [Indexed: 06/07/2023]
Abstract
Since amphibians are recognised as good models to assess the quality of environments, only few studies have dealt with the impacts of chemical contaminants on their gametes, while toxic effects at this stage will alter all the next steps of their life cycle. Therefore, we propose to investigate the oocyte maturation of Xenopus laevis in cadmium- and lead-contaminated conditions. The impacts of cadmium and lead ions were explored on events involved in the hormone-dependent process of maturation. In time-course experiments, cadmium, at the highest concentration, delayed and prevented the germinal vesicle breakdown. Even in the absence of progesterone this ion could also induce it. No such spontaneous maturation was observed after lead exposures. An acceleration of the process at the highest tested concentration of lead (90μM), in presence of progesterone, was recorded. Cytological observations highlighted that cadmium exposures drove severe disturbances of meiotic spindle morphogenesis. At last, cadmium exposures altered the MAPK pathway, regarding the activation of ERK2 and RSK, but also the activation and the activity of the MPF, by disturbing the state of phosphorylation of Cdc2 and histone H3. Xenopus laevis oocytes were affected by these metal ion exposures, notably by Cd2+. Signatures of these metal exposures on the oocyte maturation were detected. This germ cell appeared to be a relevant model to assess the effects of environmental contaminants such as metals.
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Affiliation(s)
- Sylvain Slaby
- Univ. Lille, CNRS, INRA, UMR 8576-UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France; Univ. Lille, EA 4515-LGCgE - Laboratoire Génie Civil et géo-Environnement, Cité scientifique, SN3, F-59655 Villeneuve d'Ascq, France
| | - Julie Hanotel
- Univ. Lille, CNRS, INRA, UMR 8576-UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Guillaume Marchand
- Univ. Lille, CNRS, INRA, UMR 8576-UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Arlette Lescuyer
- Univ. Lille, CNRS, INRA, UMR 8576-UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Jean-François Bodart
- Univ. Lille, CNRS, INRA, UMR 8576-UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France
| | - Alain Leprêtre
- Univ. Lille, EA 4515-LGCgE - Laboratoire Génie Civil et géo-Environnement, Cité scientifique, SN3, F-59655 Villeneuve d'Ascq, France
| | - Sébastien Lemière
- Univ. Lille, EA 4515-LGCgE - Laboratoire Génie Civil et géo-Environnement, Cité scientifique, SN3, F-59655 Villeneuve d'Ascq, France
| | - Matthieu Marin
- Univ. Lille, CNRS, INRA, UMR 8576-UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France.
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Chibowska K, Baranowska-Bosiacka I, Falkowska A, Gutowska I, Goschorska M, Chlubek D. Effect of Lead (Pb) on Inflammatory Processes in the Brain. Int J Mol Sci 2016; 17:ijms17122140. [PMID: 27999370 PMCID: PMC5187940 DOI: 10.3390/ijms17122140] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 12/10/2016] [Accepted: 12/14/2016] [Indexed: 12/29/2022] Open
Abstract
That the nervous system is the main target of lead (Pb) has long been considered an established fact until recent evidence has linked the Pb effect on the immune system to the toxic effects of Pb on the nervous system. In this paper, we present recent literature reports on the effect of Pb on the inflammatory processes in the brain, particularly the expression of selected cytokines in the brain (interleukin 6, TGF-β1, interleukin 16, interleukin 18, and interleukin 10); expression and activity of enzymes participating in the inflammatory processes, such as cyclooxygenase 2, caspase 1, nitrogen oxide synthase (NOS 2) and proteases (carboxypeptidases, metalloproteinases and chymotrypsin); and the expression of purine receptors P2X4 and P2X7. A significant role in the development of inflammatory processes in the brain is also played by microglia (residual macrophages in the brain and the spinal cord), which act as the first line of defense in the central nervous system, and astrocytes—Whose most important function is to maintain homeostasis for the proper functioning of neurons. In this paper, we also present evidence that exposure to Pb may result in micro and astrogliosis by triggering TLR4-MyD88-NF-κB signaling cascade and the production of pro-inflammatory cytokines.
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Affiliation(s)
- Karina Chibowska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Anna Falkowska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Izabela Gutowska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University, Broniewskiego 24, 71-460 Szczecin, Poland.
| | - Marta Goschorska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
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Mujaibel LM, Kilarkaje N. Mitogen-activated protein kinase signaling and its association with oxidative stress and apoptosis in lead-exposed hepatocytes. ENVIRONMENTAL TOXICOLOGY 2015; 30:513-529. [PMID: 24293362 DOI: 10.1002/tox.21928] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 11/13/2013] [Accepted: 11/20/2013] [Indexed: 06/02/2023]
Abstract
Lead toxicity has become a serious public health concern all over the world. Previous studies have shown that lead induces biochemical and structural changes in liver. However, although lead is known to alter liver functions, the underlying molecular mechanisms of hepatotoxicity are not yet clear. We hypothesized that a correlation exists between oxidative stress, apoptosis and mitogen-activated protein kinases (MAPKs) in lead-exposed liver. Wistar rats were treated with 0, 0.5%, and 1% lead acetate for 3d, 14d, and 35d and sacrificed the next day. On 4d, oxidative stress and apoptosis were correlated with downregulated expressions of ERK1/2 and p38-MAPKα/β, and upregulated expressions of JNK1/3 in males. In females, the correlation was with downregulated expressions of ERK1/2 and upregulated expressions of p38-MAPKα/β and JNK1/3. On 15d, the correlation was observed with upregulated expressions of p38-MAPKα/β in males and downregulated expressions of p38-MAPKα/β in females. In both sexes, a correlation was observed with upregulated expressions of ERK1/2 and JNK1/3 in 1% groups. On 36d, the correlation was observed with downregulated expressions of p38-MAPKα/β in males and their upregulated expressions in females. Time-dependent increase in lipid peroxidation on 15d and 36d correlated with upregulated expressions of p38-MAPKα/β in females and ERK1/2 in 1% groups in both sexes. The lower dose induced more apoptosis up to 15d in females and the higher dose induced in males on 36d. Generally, the female livers had more p38-MAPKα/β than the male livers. On 36d, the female livers showed more p38-MAPKα/β and JNK1/3 than the male livers. In conclusion, although not clearly defined, a correlation exists among oxidative stress, apoptosis, and the MAPKs in lead-exposed hepatocytes. The sex-dependent effects may be due to differences in hormonal or other physiological mechanisms. In lead-exposed hepatocytes, the apoptosis may be induced via oxidative stress-mediated alterations in the MAPKs.
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Iwakura T, Fujigaki Y, Fujikura T, Ohashi N, Kato A, Yasuda H. A high ratio of G1 to G0 phase cells and an accumulation of G1 phase cells before S phase progression after injurious stimuli in the proximal tubule. Physiol Rep 2014; 2:e12173. [PMID: 25293601 PMCID: PMC4254098 DOI: 10.14814/phy2.12173] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 12/25/2022] Open
Abstract
Proximal tubule (PT) cells can proliferate explosively after injurious stimuli. To investigate this proliferative capacity, we examined cell cycle status and the expression of cyclin-dependent kinase inhibitor p27, a G1 phase mediator, in PT cells after a proliferative or injurious stimulus. Rats were treated with lead acetate (proliferative stimulus) or uranyl acetate (UA; injurious stimulus). Isolated tubular cells were separated into PT and distal tubule (DT) cells by density-gradient centrifugation. Cell cycle status was analyzed with flow cytometry by using the Hoechst 33342/pyronin Y method. Most PT and DT cells from control rats were in G0/G1 phase, with a higher percentage of PT cells than DT cells in G1 phase. Lead acetate and UA administration promoted the G0-G1 transition and the accumulation of G1 phase cells before S phase progression. In PT cells from rats treated with lead acetate or a subnephrotoxic dose of UA, p27 levels increased or did not change, possibly reflecting G1 arrest. In contrast, p27 became undetectable before the appearance of apoptotic cells in rats treated with a nephrotoxic dose of UA. The decrease in p27 might facilitate rapid cell cycling. The decreased number of p27-positive cells was associated with PT cell proliferation in renal tissues after a proliferative or injurious stimulus. The findings suggest that a high ratio of G1 to G0 phase cells and a rapid accumulation of G1 phase cells before S phase progression in the PT is a biological strategy for safe, timely, and explosive cell proliferation in response to injurious stimuli.
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Affiliation(s)
- Takamasa Iwakura
- Internal Medicine I, Division of Nephrology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Yoshihide Fujigaki
- Internal Medicine I, Division of Nephrology, Hamamatsu University School of Medicine, Hamamatsu, Japan
- Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Tomoyuki Fujikura
- Internal Medicine I, Division of Nephrology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Naro Ohashi
- Internal Medicine I, Division of Nephrology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Akihiko Kato
- Blood Purification Unit, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Hideo Yasuda
- Internal Medicine I, Division of Nephrology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Mittal SPK, Kulkarni AP, Mathai J, Chattopadhyay S, Pal JK. Dose-dependent differential response of mammalian cells to cytoplasmic stress is mediated through the heme-regulated eIF2α kinase. Int J Biochem Cell Biol 2014; 54:186-97. [PMID: 25086227 DOI: 10.1016/j.biocel.2014.07.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 07/09/2014] [Accepted: 07/22/2014] [Indexed: 12/18/2022]
Abstract
The heme-regulated inhibitor (HRI), a regulator of translation initiation, is known to be activated and upregulated, and it acts as either a cytoprotective player promoting cell survival or as an inducer of apoptosis during stress. However, the exact role of HRI in these two responses has not been elucidated. In the present investigation, using human cell lines, we attempted to unravel the molecular mechanism(s) of HRI-mediated differential response and the involved signaling pathways. While during low dose (5 μM) lead acetate treatment, cells did not show any diminished cell survival, significant level of apoptosis was observed at high dose (100 μM) lead acetate. Based on the results of an interactome analysis, we determined the interaction of HRI with PI-3-Kca, only at a low dose stress, which is followed by phosphorylation and activation of its downstream target, AKT. Interestingly, such an interaction and AKT activation was not observed at a high dose stress. On the other hand, an increased level of APAF-1 and activation of caspases were observed. These results indicate a critical role of HRI in cell survival during low dose stress, and in apoptosis at high dose stress. Furthermore, HRI knockdown cells are sensitized even to 5 μM lead treatment leading to caspase activation and apoptosis. Our results taken together thus elucidate for the first time the molecular mechanism and the involved signaling pathways for dose-dependent differential response of mammalian cells to lead exposure. These findings thus suggest the possibility of using HRI downregulation as a therapeutic strategy to sensitize cancer cells subjected to apoptogenic drugs.
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Affiliation(s)
- Smriti P K Mittal
- Department of Biotechnology, University of Pune, Pune 411007, India; National Centre for Cell Science, University of Pune Campus, Pune 411007, India
| | | | - Jinumary Mathai
- National Centre for Cell Science, University of Pune Campus, Pune 411007, India
| | - Samit Chattopadhyay
- National Centre for Cell Science, University of Pune Campus, Pune 411007, India
| | - Jayanta K Pal
- Department of Biotechnology, University of Pune, Pune 411007, India.
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Gundacker C, Scheinast M, Damjanovic L, Fuchs C, Rosner M, Hengstschläger M. Proliferation potential of human amniotic fluid stem cells differently responds to mercury and lead exposure. Amino Acids 2011; 43:937-49. [PMID: 22101983 DOI: 10.1007/s00726-011-1154-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 11/08/2011] [Indexed: 01/07/2023]
Abstract
There are considerable gaps in our knowledge on cell biological effects induced by the heavy metals mercury (Hg) and lead (Pb). In the present study we aimed to explore the effects of these toxicants on proliferation and cell size of primary human amniotic fluid stem (AFS) cells. Monoclonal human AFS cells were incubated with three dosages of Hg and Pb (single and combined treatment; ranging from physiological to cytotoxic concentrations) and the intracellular Hg and Pb concentrations were analyzed, respectively. At different days of incubation the effects of Hg and Pb on proliferation, cell size, apoptosis, and expression of cyclins and the cyclin-dependent kinase inhibitor p27 were investigated. Whereas we found Hg to trigger pronounced effects on proliferation of human AFS cells already at low concentrations, anti-proliferative effects of Pb could only be detected at high concentrations. Exposure to high dose of Hg induced pronounced downregulation of cyclin A confirming the anti-proliferative effects observed for Hg. Co-exposure to Hg and Pb did not cause additive effects on proliferation and size of AFS cells, and on cyclin A expression. Our here presented data provide evidence that the different toxicological effects of Pb and Hg on primary human stem cells are due to different intracellular accumulation levels of these two toxicants. These findings allow new insights into the functional consequences of Pb and Hg for mammalian stem cells and into the cell biological behavior of AFS cells in response to toxicants.
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Affiliation(s)
- C Gundacker
- Institute of Medical Genetics, Medical University of Vienna, Währinger Straße 10, 1090 Vienna, Austria.
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Narayana K, Raghupathy R. DNA damage in lead-exposed hepatocytes: coexistence of apoptosis and necrosis? Drug Chem Toxicol 2011; 35:208-17. [DOI: 10.3109/01480545.2011.589849] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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12
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Kasten-Jolly J, Heo Y, Lawrence DA. Central nervous system cytokine gene expression: modulation by lead. J Biochem Mol Toxicol 2011; 25:41-54. [PMID: 21322097 DOI: 10.1002/jbt.20358] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The environmental heavy metal toxicant, lead (Pb) has been shown to be more harmful to the central nervous system (CNS) of children than to adults, given that Pb exposure affects the neural system during development. Because growth factors and cytokines play very important roles in development of the CNS, we have examined the impact of Pb exposure on the expression of cytokines during CNS development. Cytokine expression was studied in post-natal-day 21 (pnd21) mice by microarray, real-time RT-PCR, Luminex, and ELISA methodologies. BALB/c mouse pups were exposed to Pb through the dam's drinking water (0.1 mM Pb acetate), from gestation-day 8 (gd8) to pnd21. Two cytokines, interleukin-6 (IL-6) and transforming growth factor-β1 (TGF-β1), displayed significantly changed transcript levels in the presence of Pb. IL-6 and TGF-β1 both have signal transduction cascades that can cooperatively turn on the gene for the astrocyte marker glial-fibrillary acidic protein (GFAP). Microarray results indicated that Pb exposure significantly increased expression of GFAP. Pb also modulated IL-6, TGF-β1, and IL-18 protein expression in select brain regions. The deleterious effects of Pb on learning and long-term memory are posited to result from excessive astrocyte growth and/or activation with concomitant interference with neural connections. Differential neural expression of cytokines in brain regions needs to be further investigated to mechanistically associate Pb and neuroinflammation with behavioral and cognitive changes.
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Affiliation(s)
- Jane Kasten-Jolly
- Laboratory of Clinical and Experimental Endocrinology and Immunology, Wadsworth Center, 120 New Scotland Avenue, Albany, NY 12208, USA
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Khan MI, Islam N, Sahasrabuddhe AA, Mahdi AA, Siddiqui H, Ashquin M, Ahmad I. Ubiquitous hazardous metal lead induces TNF-α in human phagocytic THP-1 cells: primary role of ERK 1/2. JOURNAL OF HAZARDOUS MATERIALS 2011; 189:255-264. [PMID: 21377791 DOI: 10.1016/j.jhazmat.2011.02.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 02/11/2011] [Accepted: 02/11/2011] [Indexed: 05/30/2023]
Abstract
Induction of tumor necrosis factor-α (TNF-α) in response to lead (Pb) exposure has been implicated in its immunotoxicity. However, the molecular mechanism by which Pb upregulates the level of TNF-α is wagely known. An attempt was therefore made to elucidate the mechanistic aspect of TNF-α induction, mainly focusing transcriptional and post transcriptional regulation via mitogen activated protein kinases (MAPKs) activation. We observed that exposure of Pb to human monocytic THP-1 cells resulted in significant enhanced production of TNF-α m-RNA and protein secretion. Moreover, the stability of TNF-α m-RNA was also increased as indicated by its half life. Notably, activation of ERK 1/2, p38 and JNK in Pb exposed THP-1 was also evident. Specific inhibitor of ERK1/2, PD 98059 caused significant inhibition in production and stability of TNF-α m-RNA. However, SB 203580 partially inhibited production and stability of TNF-α m-RNA. Interestingly, a combined exposure of these two inhibitors completely blocked modulation of TNF-α m-RNA. Data tends to suggest that expression and stability of TNF-α induction due to Pb exposure is mainly regulated through ERK. Briefly, these observations are useful in understanding some mechanistic aspects of proinflammatory and immunotoxicity of Pb, a globally acknowledged key environmental contaminant.
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Affiliation(s)
- Mohd Imran Khan
- Fiber Toxicology Division, Indian Institute of Toxicology Research, Council of Scientific & Industrial Research, Mahatma Gandhi Marg, PO Box 80, Lucknow 226001, UP, India
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Hernández LG, van Steeg H, Luijten M, van Benthem J. Mechanisms of non-genotoxic carcinogens and importance of a weight of evidence approach. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2009; 682:94-109. [DOI: 10.1016/j.mrrev.2009.07.002] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 06/29/2009] [Accepted: 07/13/2009] [Indexed: 01/20/2023]
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15
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Zheng G, Zhang W, Zhang Y, Chen Y, Liu M, Yao T, Yang Y, Zhao F, Li J, Huang C, Luo W, Chen J. γ-aminobutyric acidA (GABAA) receptor regulates ERK1/2 phosphorylation in rat hippocampus in high doses of Methyl Tert-Butyl Ether (MTBE)-induced impairment of spatial memory. Toxicol Appl Pharmacol 2009; 236:239-45. [DOI: 10.1016/j.taap.2009.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 01/13/2009] [Accepted: 01/15/2009] [Indexed: 10/21/2022]
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16
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Wang CY, Wang YT, Tzeng DW, Yang JL. Lead acetate induces EGFR activation upstream of SFK and PKCα linkage to the Ras/Raf-1/ERK signaling. Toxicol Appl Pharmacol 2009; 235:244-52. [DOI: 10.1016/j.taap.2008.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 10/17/2008] [Accepted: 12/09/2008] [Indexed: 12/30/2022]
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17
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Wang CY, Lin YW, Yang JL. Activation of protein kinase Calpha signaling prevents cytotoxicity and mutagenicity following lead acetate in CL3 human lung cancer cells. Toxicology 2008; 250:55-61. [PMID: 18590793 DOI: 10.1016/j.tox.2008.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 06/04/2008] [Accepted: 06/04/2008] [Indexed: 10/22/2022]
Abstract
Protein kinase C (PKC) family of serine/threonine protein kinases is sensitive signaling transducers in response to lead acetate (Pb) that could transmit phosphorylation cascade for proliferation and de-differentiation of neural cells. However, little is known as to the impact of PKC on Pb genotoxicity. Here we investigate whether Pb activates the conventional/classical subfamily of PKC (cPKC) signaling to affect cytotoxicity and mutagenicity in CL3 human non-small-cell lung adenocarcinoma cells. Pb specifically promoted membrane localization of the alpha isoform of PKC in CL3 cells. Pb also elicited Raf-1 activation as measured by the induction of phospho-Raf-1S338 and the dissociation from the Raf-1 kinase inhibitor protein. Inhibition of cPKC activity using Gö6976 or depletion of PKCalpha by introducing specific small interfering RNA blocked the induction of phospho-Raf-1S338, phospho-MKK1/2 and phospho-ERK1/2 in cells exposed to Pb. Intriguingly, declining PKCalpha enhanced the Pb cytotoxicity and revealed the Pb mutagenicity at the hprt gene. The results suggest that PKCalpha is obligatory for activation of the Raf-1-MKK1/2-ERK1/2 signaling module and plays a defensive role against cytotoxicity and mutagenicity following Pb exposure. Results obtained in this study also support our previous report showing that ERK1/2 activity is involved in preventing Pb genotoxicity.
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Affiliation(s)
- Chun-Yu Wang
- Molecular Carcinogenesis Laboratory, Institute of Biotechnology & Department of Life Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan
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Smith JA, Maloney DJ, Hecht SM, Lannigan DA. Structural basis for the activity of the RSK-specific inhibitor, SL0101. Bioorg Med Chem 2007; 15:5018-34. [PMID: 17512736 DOI: 10.1016/j.bmc.2007.03.087] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 03/29/2007] [Accepted: 03/29/2007] [Indexed: 11/19/2022]
Abstract
Inappropriate activity of p90 ribosomal S6 kinase (RSK) has been implicated in various human cancers as well as other pathologies. We previously reported the isolation, characterization, and synthesis of the natural product kaempferol 3-O-(3'',4''-di-O-acetyl-alpha-l-rhamnopyranoside), termed SL0101 [Smith, J. A.; Poteet-Smith, C. E.; Xu, Y.; Errington, T. M.; Hecht, S. M.; Lannigan, D. A. Cancer Res., 2005, 65, 1027-1034: Xu, Y.-M; Smith, J. A.; Lannigan, D. A.; Hecht, S. M. Bioorg. Med. Chem., 2006, 14, 3974-3977: Maloney, D. J.; Hecht, S. M. Org. Lett., 2005, 7, 1097-1099]. SL0101 is a potent and specific inhibitor of RSK; therefore, we performed an analysis of the structural basis for the inhibitory activity of this lead compound. In in vitro kinase assays we found that acylation of the rhamnose moiety and the 4', 5, and 7-hydroxyl groups are responsible for maintaining a high affinity interaction of RSK with SL0101. It is likely that the hydroxyl groups facilitate RSK binding through their ability to form hydrogen bonds. To determine whether the SL0101 derivatives were specific for inhibition of RSK we analyzed their ability to preferentially inhibit the growth of the human breast cancer line, MCF-7, compared to the normal human breast line, MCF-10A. We have previously validated this differential growth assay as a convenient readout for analyzing the specificity of RSK inhibitors [Smith, J. A.; Maloney, D. J.; Clark, D. E.; Xu, Y.-M.; Hecht, S. M.; Lannigan, D. A. Bioorg. Med. Chem., 2006, 14, 6034-6042]. We found that acylation of the rhamnose moiety was essential for maintaining the selectivity for RSK inhibition in intact cells. Further, the efficacy of SL0101 in intact cells is limited by cellular uptake as well as possible hydrolysis of the acetyl groups on the rhamnose moiety by ubiquitous intracellular esterases. These studies should facilitate the development of a RSK inhibitor, based on the SL0101 pharmacophore, as an anti-cancer chemotherapeutic agent.
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Affiliation(s)
- Jeffrey A Smith
- Center for Cell Signaling, Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
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19
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Posser T, de Aguiar CBNM, Garcez RC, Rossi FM, Oliveira CS, Trentin AG, Neto VM, Leal RB. Exposure of C6 glioma cells to Pb(II) increases the phosphorylation of p38MAPK and JNK1/2 but not of ERK1/2. Arch Toxicol 2007; 81:407-14. [PMID: 17333127 DOI: 10.1007/s00204-007-0177-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Accepted: 01/09/2007] [Indexed: 01/05/2023]
Abstract
Pb(II) is a neurotoxic pollutant that produces permanent cognitive deficits in children. Pb(II) can modulate cell signaling pathways and cell viability in a variety of cell types. However, these actions are not well demonstrated on glial cells, which represent an important target for metals into the central nervous system. The present work was undertaken to determine the ability of Pb(II) in modulating the activity of mitogen activated protein kinases (MAPKs) in cultures of C6 rat glioma cells, a useful functional model for the study of astrocytes. Additionally, cell viability was analyzed by measurement of MTT reduction. Cells were exposed to lead acetate 0.1, 1, 10 microM for 24 and 48 h. MAPKs activation - in particular ERK1/2, p38(MAPK) and JNK1/2 - were analyzed by western blotting. Results showed that 10 microM Pb(II) treatment for 24 h caused a discrete stimulation of p38(MAPK) phosphorylation. However, 1 and 10 microM Pb(II) treatment for 48 h provoked a significant stimulation in the phosphorylation state of p38(MAPK) and JNK1/2. The phosphorylation state of ERK1/2 was not modified by any Pb(II) treatment. Moreover, data indicate that at 48 h treatment even 1 microM Pb(II) can be cytotoxic, causing impairment on cell viability. Therefore, depending on a long incubation period, a significant concomitant activation of p38(MAPK) and JNK1/2 by Pb(II) took place in parallel with the impairment of C6 glioma cells viability.
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Affiliation(s)
- Thaís Posser
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil
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20
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Vogetseder A, Palan T, Bacic D, Kaissling B, Le Hir M. Proximal tubular epithelial cells are generated by division of differentiated cells in the healthy kidney. Am J Physiol Cell Physiol 2006; 292:C807-13. [PMID: 16987990 DOI: 10.1152/ajpcell.00301.2006] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We searched for evidence for a contribution of stem cells in growth of the proximal S3 segments of healthy rats. According to the stem cell model, stem cells are undifferentiated and slow cycling; the bulk of cycling cells are transit amplifying, rapidly cycling cells. We show the following. 1) By continuous application of a thymidine analog (ThA) for 7 days, S3 proximal epithelial cells in healthy kidneys display a high-cycling rate. 2) Slow-cycling cells, identified by lack of ThA uptake during 14 days of continuous ThA application up to death and by expression of the cell cycle protein Ki67 at death, have the same degree of differentiation as quiescent cells. 3) To detect rapidly cycling cells, rats were killed at various time points after injection of a ThA. Double immunofluorescence for ThA and a cell cycle marker was performed, with colocalization indicating successive divisions. During one week after division, daughter cells display a very low proliferation rate, indicating the absence of rapidly cycling cells. 4) Labeling with cyclin D1 showed that this low proliferation rate is due to cycle arrest. 5) More than 50% of the S3 cells entered the cell cycle 36 h after a potent proliferative stimulus (lead acetate injection). We conclude that generation of new cells in the proximal tubule relies on division of differentiated, normally slow-cycling cells. These may rapidly enter the cycle under an adequate stimulus.
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Affiliation(s)
- Alexander Vogetseder
- Institute of Anatomy, Univ. of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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21
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Leal RB, Ribeiro SJ, Posser T, Cordova FM, Rigon AP, Zaniboni Filho E, Bainy ACD. Modulation of ERK1/2 and p38(MAPK) by lead in the cerebellum of Brazilian catfish Rhamdia quelen. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2006; 77:98-104. [PMID: 16360892 DOI: 10.1016/j.aquatox.2005.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 10/28/2005] [Accepted: 11/08/2005] [Indexed: 05/05/2023]
Abstract
Lead (Pb2+) is a neurotoxic trace metal, widespread in aquatic environment that can change physiologic, biochemical and behavioral parameters in diverse fish species. Chemical exposure may drive modulation of mitogen-activated protein kinases (MAPKs) that are a family of highly conserved enzymes which comprise ubiquitous groups of signaling proteins playing critical regulatory roles in cell physiology. Extracellular signal-regulated kinases (ERK1/2) and p38(MAPK) control complex programs such as gene expression, embryogenesis, cell differentiation, cell proliferation, cell death and synaptic plasticity. Little information is available about MAPKs in aquatic organisms and their modulation by trace metals. The aim of this work was to determine the modulation of ERK1/2 and p38(MAPK) phosphorylation by Pb2+ in vivo and in vitro, in cerebellar slices of the catfish, Rhamdia quelen. In the in vitro model, slices were incubated for 3 h with lead acetate (1-10 microM). In the in vivo studies, the animals were exposed for 2 days to lead acetate (1 mg L(-1)). ERK1/2 and p38(MAPK) (total and phosphorylated forms) were immunodetected in cerebellar slices by Western blotting. Pb2+ added in vitro at 5 and 10 microM increased significantly the phosphorylation of both MAPKs. The in vivo exposed animals also showed a significant increase of ERK1/2 and p38(MAPK) phosphorylation without changes in the total content of the enzymes. In conclusion, the present work indicates that it is possible to evaluate the ERK1/2 and p38(MAPK) activation in the central nervous system (CNS) of a freshwater fish largely distributed in South America. Moreover, Pb2+, an important environmental pollutant may activate in vitro and in vivo ERK1/2 and p38(MAPK) enzymes. These findings are important considering the functional and ecologic implications associated to Pb2+ exposure of a freshwater fish species, such as R. quelen, and the roles of ERK1/2 and p38(MAPK) in the control of brain development, neuroplasticity and cell death.
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Affiliation(s)
- Rodrigo B Leal
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC 88040-900, Brazil.
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22
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Toscano CD, Guilarte TR. Lead neurotoxicity: From exposure to molecular effects. ACTA ACUST UNITED AC 2005; 49:529-54. [PMID: 16269318 DOI: 10.1016/j.brainresrev.2005.02.004] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Revised: 02/11/2005] [Accepted: 02/14/2005] [Indexed: 10/25/2022]
Abstract
The effects of lead (Pb(2+)) on human health have been recognized since antiquity. However, it was not until the 1970s that seminal epidemiological studies provided evidence on the effects of Pb(2+) intoxication on cognitive function in children. During the last two decades, advances in behavioral, cellular and molecular neuroscience have provided the necessary experimental tools to begin deciphering the many and complex effects of Pb(2+) on neuronal processes and cell types that are essential for synaptic plasticity and learning and memory in the mammalian brain. In this review, we concentrate our efforts on the effects of Pb(2+) on glutamatergic synapses and specifically on the accumulating evidence that the N-methyl-D-aspartate type of excitatory amino acid receptor (NMDAR) is a direct target for Pb(2+) effects in the brain. Our working hypothesis is that disruption of the ontogenetically defined pattern of NMDAR subunit expression and NMDAR-mediated calcium signaling in glutamatergic synapses is a principal mechanism for Pb(2+)-induced deficits in synaptic plasticity and in learning and memory documented in animal models of Pb(2+) neurotoxicity. We provide an introductory overview of the magnitude of the problem of Pb(2+) exposure to bring forth the reality that childhood Pb(2+) intoxication remains a major public health problem not only in the United States but worldwide. Finally, the latest research offers some hope that the devastating effects of childhood Pb(2+) intoxication in a child's ability to learn may be reversible if the appropriate stimulatory environment is provided.
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MESH Headings
- Animals
- Child
- Humans
- Lead/toxicity
- Lead Poisoning, Nervous System/metabolism
- Lead Poisoning, Nervous System/pathology
- Lead Poisoning, Nervous System/psychology
- Lead Poisoning, Nervous System, Childhood/epidemiology
- Lead Poisoning, Nervous System, Childhood/metabolism
- Lead Poisoning, Nervous System, Childhood/pathology
- Lead Poisoning, Nervous System, Childhood/psychology
- Receptors, N-Methyl-D-Aspartate/biosynthesis
- Receptors, N-Methyl-D-Aspartate/physiology
- Signal Transduction/drug effects
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Affiliation(s)
- Christopher D Toscano
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
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Giuliani R, Bettoni F, Leali D, Morandini F, Apostoli P, Grigolato P, Cesana BM, Aleo MF. Focal adhesion molecules as potential target of lead toxicity in NRK-52E cell line. FEBS Lett 2005; 579:6251-8. [PMID: 16253243 DOI: 10.1016/j.febslet.2005.09.097] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Revised: 09/20/2005] [Accepted: 09/26/2005] [Indexed: 10/25/2022]
Abstract
In this study, we investigated the influence of inorganic lead (Pb(II)), an environmental pollutant having nephrotoxic action, on the focal adhesion (FA) organization of a rat kidney epithelial cell line (NRK-52E). In particular, we evaluated the effects of the metal on the recruitment of paxillin, focal adhesion kinase, vinculin and cytoskeleton proteins at the FAs complexes. We provided evidences that, in proliferating NRK-52E cell cultures, low concentrations of Pb(II) affect the cell adhesive ability and stimulate the disassembly of FAs, thus inhibiting the integrin-activated signalling. These effects appeared to be strictly associated to the Pb-induced arrest of cell cycle at G0/G1 phase also proved in this cell line.
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Affiliation(s)
- Roberta Giuliani
- Unit of Biochemistry, School of Medicine, University of Brescia, Italy
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24
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Cabell L, Ferguson C, Luginbill D, Kern M, Weingart A, Audesirk G. Differential induction of heme oxygenase and other stress proteins in cultured hippocampal astrocytes and neurons by inorganic lead. Toxicol Appl Pharmacol 2004; 198:49-60. [PMID: 15207648 DOI: 10.1016/j.taap.2004.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Accepted: 03/01/2004] [Indexed: 01/23/2023]
Abstract
We examined the effects of exposure to inorganic lead (Pb2+) on the induction of stress proteins in cultured hippocampal neurons and astrocytes, with particular emphasis on the induction of heme oxygenase-1 (HO-1). In radiolabeled neuronal cultures, Pb2+ exposure had no significant effect on the synthesis of any protein at any concentration (up to 250 microM) or duration of exposure (up to 4 days). In radiolabeled astrocyte cultures, however, Pb2+ exposure (100 nM to 100 microM; 1-4 days) increased synthesis of proteins with approximate molecular weights of 23, 32, 45, 57, 72, and 90 kDa. Immunoblot experiments showed that Pb2+ exposure (100 nM to 10 microM, 1-14 days) induces HO-1 synthesis in astrocytes, but not in neurons; this is probably the 32-kDa protein. The other heme oxygenase isoform, HO-2, is present in both neurons and astrocytes, but is not inducible by Pb2+ at concentrations up to 100 microM. HO-1 can be induced by a variety of stimuli. We found that HO-1 induction in astrocytes is increased by combined exposure to Pb2+ and many other stresses, including heat, nitric oxide, H2O2, and superoxide. One of the stimuli that may induce HO-1 is oxidative stress. Lead exposure causes oxidative stress in many cell types, including astrocytes. Induction of HO-1 by Pb2+ is reduced by the hydroxyl radical scavengers dimethylthiourea (DMTU) and mannitol, but not by inhibitors of calmodulin, calmodulin-dependent protein kinases, protein kinase C, or extracellular signal-regulated kinases (ERK). Therefore, we conclude that oxidative stress is an important mechanism by which Pb2+ induces HO-1 synthesis in astrocytes.
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Affiliation(s)
- Leigh Cabell
- Biology Department, University of Colorado at Denver, Denver, CO 80217-3364, USA
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25
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Zhang Q, Bratton GR, Agarwal RK, Calise D, Kugel G, Wan Y, Kumar AM. Lead-induced cell signaling cascades in GT1-7 cells. Brain Res Bull 2003; 61:207-17. [PMID: 12832008 DOI: 10.1016/s0361-9230(03)00127-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The effects of lead on the signal transduction pathways that may be involved in the release of gonadotropin-releasing hormone (GnRH) from neurons in the hypothalamus have not been well defined. Using the GT1-7 cell line, an in vitro model for GnRH-secreting neurons, we examined signal transduction pathways directly affected by lead. We found that lead-induced phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1 and ERK2), as well as p90RSK and cAMP response element-binding protein (CREB), but did not induce IkappaB degradation. MEK1/2 inhibitor (PD98059) suppressed lead-induced ERK and p90RSK activation. Neither PKC inhibitors (Go6983, Go6976) nor CaMKII inhibitor (KN-62) had a pronounced effect on lead-induced ERK1 and ERK2 phosphorylation. However, MEK1/2 inhibitor, CaMKII inhibitor, and PKC inhibitor significantly suppressed lead-induced CREB phosphorylation. These results indicate that lead-activated PKC, CaMKII and MEK/ERK/p90RSK pathways simultaneously, all of which contributed to CREB phosphorylation. Our results also indicate that lead-induced p90RSK and CREB activation does not alter expression of early response genes like c-fos. We conclude that lead activates PKC, CaMKII or MEK-ERK-p90RSK pathways in GT1-7 cells, leading to CREB phosphorylation and modulation of gene expression.
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Affiliation(s)
- Quanshun Zhang
- Department of Biomedical Sciences, Tufts University School of Veterinary Medicine, 200 Westboro Road, N., Grafton, MA 01536, USA
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26
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Chang F, Steelman LS, Lee JT, Shelton JG, Navolanic PM, Blalock WL, Franklin RA, McCubrey JA. Signal transduction mediated by the Ras/Raf/MEK/ERK pathway from cytokine receptors to transcription factors: potential targeting for therapeutic intervention. Leukemia 2003; 17:1263-93. [PMID: 12835716 DOI: 10.1038/sj.leu.2402945] [Citation(s) in RCA: 513] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The Ras/Raf/Mitogen-activated protein kinase/ERK kinase (MEK)/extracellular-signal-regulated kinase (ERK) cascade couples signals from cell surface receptors to transcription factors, which regulate gene expression. Depending upon the stimulus and cell type, this pathway can transmit signals, which result in the prevention or induction of apoptosis or cell cycle progression. Thus, it is an appropriate pathway to target for therapeutic intervention. This pathway becomes more complex daily, as there are multiple members of the kinase and transcription factor families, which can be activated or inactivated by protein phosphorylation. The diversity of signals transduced by this pathway is increased, as different family members heterodimerize to transmit different signals. Furthermore, additional signal transduction pathways interact with the Raf/MEK/ERK pathway to regulate positively or negatively its activity, or to alter the phosphorylation status of downstream targets. Abnormal activation of this pathway occurs in leukemia because of mutations at Ras as well as genes in other pathways (eg PI3K, PTEN, Akt), which serve to regulate its activity. Dysregulation of this pathway can result in autocrine transformation of hematopoietic cells since cytokine genes such as interleukin-3 and granulocyte/macrophage colony-stimulating factor contain the transacting binding sites for the transcription factors regulated by this pathway. Inhibitors of Ras, Raf, MEK and some downstream targets have been developed and many are currently in clinical trials. This review will summarize our current understanding of the Ras/Raf/MEK/ERK signal transduction pathway and the downstream transcription factors. The prospects of targeting this pathway for therapeutic intervention in leukemia and other cancers will be evaluated.
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Affiliation(s)
- F Chang
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, NC 27858, USA
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Woźniak K, Blasiak J. In vitro genotoxicity of lead acetate: induction of single and double DNA strand breaks and DNA-protein cross-links. Mutat Res 2003; 535:127-39. [PMID: 12581530 DOI: 10.1016/s1383-5718(02)00295-4] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Lead is present in the natural and occupational environment and is reported to interact with DNA, but the mechanism of this interaction is not fully understood. Using the alkaline comet assay we showed that lead acetate at 1-100 microM induced DNA damage in isolated human lymphocytes measured the change in the comet tail length. At 1 and 10 microM we observed an increase in the tail length, whereas at 100 microM a decrease was seen. The former effect could follow from the induction of DNA strand breaks and/or alkali-labile sites (ALS), the latter from the formation of DNA-DNA and/or DNA-protein cross-links. No difference was observed between tail length for the alkaline and pH 12.1 versions of the assay, which indicates that strand breaks and not ALS are responsible for the tail length increase induced by lead. The neutral version of the test revealed that lead acetate induced DNA double-strand breaks at all concentrations tested. The presence of spin traps, 5,5-dimethyl-pyrroline N-oxide (DMPO) and N-tert-butyl-alpha-phenylnitrone (PBN) did not influence the level of DNA damage induced by lead. Post-treatment of the lead-damaged DNA (at 100 microM treatment concentration) by endonuclease III (Endo III) and formamidopyrimidine-DNA glycosylase (Fpg), enzymes recognizing oxidized DNA bases, as well as 3-methyladenine-DNA glycosylase II, an enzyme recognizing alkylated bases, gave rise to a significant increase in the extent of DNA damage. Proteinase K caused an increase in comet tail length, suggesting that lead acetate might cross-link DNA with nuclear proteins. Vitamin A, E, C, calcium chloride and zinc chloride acted synergistically on DNA damage evoked by lead. The results obtained suggest that lead acetate may induce single-strand breaks (SSB) and double-strand breaks (DSB) in DNA as well as DNA-protein cross-links. The participation of free radicals in DNA-damaging potential of lead is not important and it concerns other reactive species than could be trapped by DMPO or PBN.
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Affiliation(s)
- Katarzyna Woźniak
- Department of Molecular Genetics, University of Lodz, Banacha 12/16, 90-237, Lodz, Poland.
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