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The critical role of the cellular thiol homeostasis in cadmium perturbation of the lung extracellular matrix. Toxicology 2009; 267:60-9. [PMID: 19879314 DOI: 10.1016/j.tox.2009.10.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 10/16/2009] [Accepted: 10/19/2009] [Indexed: 11/23/2022]
Abstract
Cadmium (Cd) inhalation can result in emphysema. Cd exposure of rat lung fibroblasts (RFL6) enhanced levels of metal scavenging thiols, e.g., metallothionein (MT) and glutathione (GSH), and the heavy chain of gamma-glutamylcysteine synthetase (gamma-GCS), a key enzyme for GSH biosynthesis, concomitant with downregulation of lysyl oxidase (LO), a copper-dependent enzyme for crosslinking collagen and elastin in the extracellular matrix (ECM). Cd downregulation of LO in treated cells was closely accompanied by suppression of synthesis of collagen, a major structure component of the lung ECM. Using rats intratracheally instilled with cadmium chloride (30 microg, once a week) as an animal model, we further demonstrated that although 2-week Cd instillation induced a non-significant change in the lung LO activity and collagen synthesis, 4- and 6-week Cd instillation resulted in a steady decrease in the lung LO and collagen expression. The lung MT and total GSH levels were both upregulated upon the long-term Cd exposure. Emphysematous lesions were generated in lungs of 6-week Cd-dosed rats. Increases of cellular thiols by transfection of cells with MT-II expression vectors or treatment of cells with GSH monoethyl ester, a GSH delivery system, markedly inhibited LO mRNA levels and catalytic activities in the cell model. Thus, Cd upregulation of cellular thiols may be a critical cellular event facilitating downregulation of LO, a potential mechanism for Cd-induced emphysema.
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Gao S, Zhao Y, Kong L, Toselli P, Chou IN, Stone P, Li W. Cloning and characterization of the rat lysyl oxidase gene promoter: identification of core promoter elements and functional nuclear factor I-binding sites. J Biol Chem 2007; 282:25322-37. [PMID: 17597074 DOI: 10.1074/jbc.m610108200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lysyl oxidase (LO) stabilizes the extracellular matrix by cross-linking collagen and elastin. To assess the transcriptional regulation of LO, we cloned the 5'-flanking region with 3,979 bp of the rat LO gene. LO transcription started at multiple sites clustered at the region from -78 to -51 upstream of ATG. The downstream core promoter element functionally independent of the initiator predominantly activated the TATA-less LO gene. 5' Deletion assays illustrated a sequence of 804 bp upstream of ATG sufficient for eliciting the maximal promoter activity and the region -709/-598 exhibiting strongly enhancing effects on the reporter gene expression in transiently transfected RFL6 cells. DNase I footprinting assays showed a protected pattern existing in the fragment -612/-580, which contains a nuclear factor I (NFI)-binding site at the region -594/-580 confirmed by electrophoretic mobility supershift assays. Mutations on this acting site decreased both NFI binding affinity in gel shift assays and stimulation of SV40 promoter activities in cells transfected with the NFI-binding site-SV40 promoter chimeric construct. Furthermore, at least two functional NFI-binding sites, including another one located at -147/-133, were identified in the LO promoter region -804/-1. Only NFI-A and NFI-B were expressed in rat lung fibroblasts, and their interaction with the LO gene was sensitively modulated by exogenous stimuli such as cigarette smoke condensate. In conclusion, the isolated rat LO gene promoter contains functionally independent initiator and downstream core promoter elements, and the conserved NFI-binding sites play a critical role in the LO gene activation.
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Affiliation(s)
- Song Gao
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Zhao Y, Gao S, Chou IN, Toselli P, Stone P, Li W. Inhibition of the expression of lysyl oxidase and its substrates in cadmium-resistant rat fetal lung fibroblasts. Toxicol Sci 2006; 90:478-89. [PMID: 16432278 DOI: 10.1093/toxsci/kfj112] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Copper (Cu)-dependent lysyl oxidase (LO) catalyzes crosslinking of collagen and elastin stabilizing the extracellular matrix (ECM). Chronic inhalation of cadmium (Cd), a toxic metal, induces emphysema. To probe mechanisms of Cd injury to the lung, we developed Cd-resistant (CdR) cells from rat fetal lung fibroblasts (RFL6) by chronic exposure to CdCl(2) from 1 to 40 microM and further examined their expressions of LO, LO substrates, and Cu-scavenging thiols. Levels of cellular thiols, metallothionein, and glutathione in CdR cells were elevated to 13.0- and 3.2-fold of parental controls, respectively, whereas LO mRNA and protein levels were markedly reduced in these cells, with catalytic activity declining to only 16% of the parental control. A conspicuous 52 kDa species rather then the normal 50 kDa proenzyme appeared in the CdR cell extract but not in the conditioned medium, which was codistributed with the endoplasmic reticulum marker [DiOC5(3)] within the cell, implying the Cd-induced 52 kDa species as a product of an abnormal LO-processing defect in secretion. Addition of Cu into CdR cell cultures enhanced the expression of LO mRNA, protein and catalytic activities reflecting limitation of Cu bioavailability for LO in these cells. With inhibition of LO, CdR cells also displayed downregulation of collagen and elastin, substrates of LO. Restoration of collagen synthesis by exposure of CdR cells to purified LO or Cu suggests that inhibition of LO and limitation of Cu cofactor by Cd, as key phenotype changes, accelerated collagen and elastin damage, a critical event pertinent to emphysema pathogenesis.
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Affiliation(s)
- Yinzhi Zhao
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Hardman B, Manuelpillai U, Wallace EM, van de Waasenburg S, Cater M, Mercer JFB, Ackland ML. Expression and Localization of Menkes and Wilson Copper Transporting ATPases in Human Placenta. Placenta 2004; 25:512-7. [PMID: 15135234 DOI: 10.1016/j.placenta.2003.11.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2003] [Revised: 11/17/2003] [Accepted: 11/26/2003] [Indexed: 10/26/2022]
Abstract
Copper is an essential trace element necessary for normal growth and development. During pregnancy, copper is transported from the maternal circulation to the fetus by mechanisms which have not been clearly elucidated. Two copper transporting ATPases, Menkes (ATP7A; MNK) and Wilson (ATP7B; WND) are known to be expressed in the placenta and are thought to have a role in copper transport to the fetus. In this study, the expression and localization of the MNK and WND proteins in the human placenta were investigated in detail using immunoperoxidase and double-label immunohistochemistry. MNK and WND are differentially localized within the placenta. MNK is present in the syncytiotrophoblast, the cytotrophoblast and the fetal vascular endothelial cells whereas WND is only in the syncytiotrophoblast. Placental levels of both proteins, measured by Western blot analysis, did not change across pregnancy. These data offer some insights into possible roles for MNK and WND within the placenta.
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Affiliation(s)
- B Hardman
- School of Biological and Chemical Sciences, Centre for Cellular and Molecular Biology, Deakin University, 221 Burwood Highway, Burwood Campus, Burwood, Melbourne, Victoria 3125, Australia
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Keen CL, Clegg MS, Hanna LA, Lanoue L, Rogers JM, Daston GP, Oteiza P, Uriu-Adams JY. The plausibility of micronutrient deficiencies being a significant contributing factor to the occurrence of pregnancy complications. J Nutr 2003; 133:1597S-1605S. [PMID: 12730474 DOI: 10.1093/jn/133.5.1597s] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Numerous studies support the concept that a major cause of pregnancy complications can be suboptimal embryonic and fetal nutrition. Although the negative effects of diets low in energy on pregnancy outcome are well documented, less clear are the effects of diets that are low in one or more essential micronutrients. However, several observational and intervention studies suggest that diets low in essential vitamins and minerals can pose a significant reproductive risk in diverse human populations. Although maternal nutritional deficiencies typically occur as a result of low dietary intakes of essential nutrients, nutritional deficiencies at the level of the conceptus can arise through multiple mechanisms. Evidence from experimental animals supports the concept that in addition to primary deficiencies, secondary embryonic and fetal nutritional deficiencies can be caused by diverse factors including genetics, maternal disease, toxicant insults and physiological stressors that can trigger a maternal acute phase response. These secondary responses may be significant contributors to the occurrence of birth defects. An implication of the above is that the frequency and severity of pregnancy complications may be reduced through an improvement in the micronutrient status of the mother.
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Affiliation(s)
- Carl L Keen
- Department of Nutrition and Internal Medicine, University of California, Davis, CA 95616, USA.
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Keen CL, Hanna LA, Lanoue L, Uriu-Adams JY, Rucker RB, Clegg MS. Developmental consequences of trace mineral deficiencies in rodents: acute and long-term effects. J Nutr 2003; 133:1477S-80S. [PMID: 12730447 DOI: 10.1093/jn/133.5.1477s] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Approximately 3% of infants born have at least one serious congenital malformation. In the U.S., an average of 10 infants per thousand die before 1 y of life; about half of these deaths can be attributed to birth defects, low birth weight or prematurity. Although the causes of developmental abnormalities are clearly multifactorial in nature, we suggest that a common factor contributing to the occurrence of developmental abnormalities is suboptimal mineral nutrition during embryonic and fetal development. Using zinc and copper as examples, evidence is presented that nutritional deficiencies can rapidly affect the developing conceptus and result in gross structural abnormalities. Deficits of zinc or copper can result in rapid changes in cellular redox balance, tissue oxidative stress, inappropriate patterns of cell death, alterations in the migration of neural crest cells and changes in the expression of key patterning genes. In addition to well-recognized malformations, mineral deficiencies during perinatal development can result in behavioral, immunological and biochemical abnormalities that persist into adulthood. Although these persistent defects can in part be attributed to subtle morphological abnormalities, in other cases they may be secondary to epigenetic or developmental changes in DNA methylation patterns. Epigenetic defects combined with subtle morphological abnormalities can influence an individual's risk for certain chronic diseases and thus influence his or her risk for morbidity and mortality later in life.
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Affiliation(s)
- Carl L Keen
- Department of Nutrition, University of California, Davis, CA 95616, USA.
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Braun-Falco O, Plewig G, Wolff HH, Burgdorf WHC. Disorders of Mineral Metabolism. Dermatology 2000. [DOI: 10.1007/978-3-642-97931-6_46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Nath R. Copper deficiency and heart disease: molecular basis, recent advances and current concepts. Int J Biochem Cell Biol 1997; 29:1245-54. [PMID: 9451822 DOI: 10.1016/s1357-2725(97)00060-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Copper is an essential trace element and has profound influence on cardiac myopathy and heart metabolism. Dietary Cu restriction in rats results in cardiomyopathy, and affects the integrity of the basal lamina of cardiac myocytes and capillaries. Decreased levels of delta subunits of ATP synthetase and nuclear encoded subunits of cytochrome oxidase system have been observed. Alteration in expression of glutathione peroxidase and catalase in heart and liver in Cu deficiency (Cu-) has been noted involving both transcriptional and post transcriptional mechanisms. A short description of two genetically inherited disorders of Cu metabolism, i.e. Wilson's disease and Menkes' disease, and Indian childhood cirrhosis (environmental and/or genetic) have been included to illustrate that advances in the knowledge of Cu cellular transport gives a better understanding of the molecular basis of the pathophysiology of these diseases. Menkes' disease, a human model of defective Cu transport and Cu- has shown many pathological changes, similar to those of heart disease in Cu-. The recent cloning of four genes of putative Cu pumping ATPases (Cu-ATPases) from widely different sources, i.e. two from Enterococcus hirae and one each from Wilson's and Menkes disease patients (which are defective in Cu transport and metabolism), has opened a new chapter in the study of Cu cellular transport and metabolism. The encoded gene products, i.e. Cu-ATPases, show extensive homology and are members of a new class of ATP-driven Cu pumps involved in regulation of cellular Cu. Further, Cu transport by Cop B-ATPase (E. hirae) in membrane vesicles and in isolated rat liver plasma membrane has provided biochemical evidence of its role in ATP-driven Cu transport. In this short review I have critically examined the current evidence of the molecular basis of the pathophysiology of cardiomyopathy in Cu- and, have indicated the possible role of P-type Cu ATPase which may be one of the obligatory factors contributing to cardiomyopathy in experimental animals and probably humans. Experimental verification of this hypothesis will be the aim of future studies.
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Affiliation(s)
- R Nath
- Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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Abstract
This study evaluated the use of IEC-6 cells as a model for studying lead (Pb) transport by intestinal epithelial cells (IECs) and examined potential transport mechanisms for Pb uptake and extrusion. Pb accumulation in IEC-6 cells exposed to 5 and 10 microM Pb for up to 60 min was time- and dose-dependent. Reduction of incubation temperature significantly reduced the total cellular Pb content of IEC-6 cells. Simultaneous exposed of cells to zinc (Zn) and Pb resulted in decreased total cellular Pb contents compared to total cellular Pb contents of cells exposed to Pb only. IEC-6 cells treated with ouabain (1 mM) or sodium azide (1 mM) and 5 microM Pb accumulated more Pb than cells exposed to Pb only. Cells treated with p-chloromercuribenzensulfonic acid (50 microM), p-chloromercuribenzoic acid (50 microM), or iodoacetimide (50 microM) accumulated less Pb than cells treated with Pb only. We conclude that Pb uptake by IEC-6 cells depends on the extracellular Pb concentration. Our data suggest that the mechanism of Pb uptake by IECs is complex, and that Pb transport in IEC-6 cells is time- and temperature-dependent, involves sulfhydryl groups, and is decreased by the presence of Zn. Extrusion of Pb is at least partially dependent on metabolic energy.
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Affiliation(s)
- C M Dekaney
- Department of Veterinary Anatomy and Public Health, Texas A&M University, College Station 77843, USA
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Affiliation(s)
- A Taylor
- Clinical Laboratory, Royal Surrey County Hospital, Guildford, UK
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Qian Y, Majumdar S, Reddy MC, Harris ED. Coincident expression of Menkes gene with copper efflux in human placental cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 270:C1880-4. [PMID: 8764173 DOI: 10.1152/ajpcell.1996.270.6.c1880] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BeWo cells, a human choriocarcinoma cell line, have a high-affinity system for transporting copper ions into the cell (Km = 0.21 microM) but are sluggish in releasing copper back into the medium from preloaded cells. The slow efflux rate has recently been shown to correlate with a failure of BeWo cells to express the Menkes transcript [Y. Qian, E. Tiffany-Castiglioni, and E. D. Harris. Am. J. Physiol. 271 (Cell Physiol. 40). In press]. We have now determined that only when BeWo cells were grown on plastic surfaces such as petri dishes or flasks did they display negligible release and enhanced retention of 67Cu. Reverse transcriptase-polymerase chain reaction with the use of primers selective for the Menkes gene failed to show any evidence of a Menkes transcript in cells cultured on plastic surfaces. In contrast, cells grown on porous filters previously shown to allow apical and basolateral surfaces to develop did display the transcript and showed significant copper release with normal retention. Release of copper from filter-grown cells was blocked with p-chloromercuribenzoate, thus confirming sulfhydryl group involvement. Absorption of the 67Cu, either as a free ion or bound to ceruloplasmin, was unaffected by the different culture conditions. The data link the Menkes gene product with the ability of cells to release copper ions. They also suggest that the expression of the Menkes gene may be regulated by the development of polarized cell membranes.
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Affiliation(s)
- Y Qian
- Department of Biochemistry and Biophysics. Texas A&M University, College Station 77843-2128, USA
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Heavy metal toxicity following apical and basolateral exposure in the human intestinal cell line Caco-2. Toxicol In Vitro 1996; 10:27-36. [DOI: 10.1016/0887-2333(95)00097-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/1995] [Indexed: 11/22/2022]
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Millichap JG. Menkes Disease: Copper-Histidine Therapy. Pediatr Neurol Briefs 1993. [DOI: 10.15844/pedneurbriefs-7-11-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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