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Zeng X, Wei T, Wang X, Liu Y, Tan Z, Zhang Y, Feng T, Cheng Y, Wang F, Ma B, Qin W, Gao C, Xiao J, Wang C. Discovery of metal-binding proteins by thermal proteome profiling. Nat Chem Biol 2024; 20:770-778. [PMID: 38409364 DOI: 10.1038/s41589-024-01563-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 01/26/2024] [Indexed: 02/28/2024]
Abstract
Metal-binding proteins (MBPs) have various and important biological roles in all living species and many human diseases are intricately linked to dysfunctional MBPs. Here, we report a chemoproteomic method named 'metal extraction-triggered agitation logged by thermal proteome profiling' (METAL-TPP) to globally profile MBPs in proteomes. The method involves the extraction of metals from MBPs using chelators and monitoring the resulting protein stability changes through thermal proteome profiling. Applying METAL-TPP to the human proteome with a broad-spectrum chelator, EDTA, revealed a group of proteins with reduced thermal stability that contained both previously known MBPs and currently unannotated MBP candidates. Biochemical characterization of one potential target, glutamine-fructose-6-phosphate transaminase 2 (GFPT2), showed that zinc bound the protein, inhibited its enzymatic activity and modulated the hexosamine biosynthesis pathway. METAL-TPP profiling with another chelator, TPEN, uncovered additional MBPs in proteomes. Collectively, this study developed a robust tool for proteomic discovery of MBPs and provides a rich resource for functional studies of metals in cell biology.
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Affiliation(s)
- Xin Zeng
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Tiantian Wei
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Xianghe Wang
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Yuan Liu
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Zhenshu Tan
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Yihai Zhang
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Tianyu Feng
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Yao Cheng
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Fengzhang Wang
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Bin Ma
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Wei Qin
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Chuanping Gao
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Junyu Xiao
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.
| | - Chu Wang
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
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Canevali C, Sansonetti A, Rampazzi L, Monticelli D, D'Arienzo M, Di Credico B, Ghezzi E, Mostoni S, Nisticò R, Scotti R. The Chemistry of Chelation for Built Heritage Cleaning: The Removal of Copper and Iron Stains. Chempluschem 2024:e202300709. [PMID: 38683651 DOI: 10.1002/cplu.202300709] [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: 11/30/2023] [Revised: 04/29/2024] [Accepted: 04/29/2024] [Indexed: 05/01/2024]
Abstract
Chelators are widely used in conservation treatments to remove metal stains from marble, travertine, and limestone surfaces. In the current review the chemical aspects underlying the use of chelators for the removal of copper and iron stains from built heritage are described and clear criteria for the selection of the most efficient stain removal treatment are given. The main chelator structural features are outlined and the operating conditions for effective metal stain removal (pH, time of application, etc.) discussed, with a particular emphasis on the ability to form stable metal complexes, the high selectivity towards the metal that should be removed, and the high sustainability for the environment. Dense matrices often host chelators for higher effectiveness, and further research is required to clarify their role in the cleaning process. Then, relevant case studies of copper and iron stain removal are discussed. On these bases, the most effective chelators for copper and stain removal are indicated, providing chemists and conservation scientists with scientific support for conservation operations on stone works of art and opening the way to the synthesis of new chelators.
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Affiliation(s)
- Carmen Canevali
- Department of Materials Science, University of Milano-Bicocca, via Roberto Cozzi 55, 20125, Milan, Italy
| | - Antonio Sansonetti
- Istituto di Scienze del Patrimonio Culturale (ISPC-CNR), Via Roberto Cozzi 53, 20125, Milan, Italy
| | - Laura Rampazzi
- Dipartimento di Scienze Umane e dell'Innovazione per il Territorio (DiSUIT), Università degli Studi dell'Insubria, Via Sant'Abbondio 12, 22100, Como, Italy
| | - Damiano Monticelli
- Department of Science and High Technology, Università degli Studi dell'Insubria, Via Valleggio 11, Como, Italy
| | - Massimiliano D'Arienzo
- Department of Materials Science, University of Milano-Bicocca, INSTM, via Roberto Cozzi 55, 20125, Milan, Italy
| | - Barbara Di Credico
- Department of Materials Science, University of Milano-Bicocca, INSTM, via Roberto Cozzi 55, 20125, Milan, Italy
| | - Elena Ghezzi
- Brera Academy of Fine Arts, Via Brera 28, 20121, Milan, Italy
| | - Silvia Mostoni
- Department of Materials Science, University of Milano-Bicocca, INSTM, via Roberto Cozzi 55, 20125, Milan, Italy
| | - Roberto Nisticò
- Department of Materials Science, University of Milano-Bicocca, INSTM, via Roberto Cozzi 55, 20125, Milan, Italy
| | - Roberto Scotti
- Department of Materials Science, University of Milano-Bicocca, INSTM, via Roberto Cozzi 55, 20125, Milan, Italy
- Institute for Photonics and Nanotechnologies-CNR, Via alla Cascata 56/C, 38123, Povo (TN), Italy
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Wu C, Han J, Wu S, Liu C, Zhang Q, Tang J, Liu Z, Yang J, Chen Y, Zhuo Y, Li Y. Reduced Zn 2+ promotes retinal ganglion cells survival and optic nerve regeneration after injury through inhibiting autophagy mediated by ROS/Nrf2. Free Radic Biol Med 2024; 212:415-432. [PMID: 38134974 DOI: 10.1016/j.freeradbiomed.2023.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/05/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023]
Abstract
The molecular mechanism of how reduced mobile zinc (Zn2+) affected retinal ganglion cell (RGC) survival and optic nerve regeneration after optic nerve crush (ONC) injury remains unclear. Here, we used conditionally knocked out ZnT-3 in the amacrine cells (ACs) of mice (CKO) in order to explore the role of reactive oxygen species (ROS), nuclear factor erythroid 2-related factor 2 (NFE2L2, Nrf2) and autophagy in the protection of RGCs and axon regeneration after ONC injury. We found that reduced Zn2+ can promote RGC survival and axonal regeneration by decreasing ROS, activating Nrf2, and inhibiting autophagy. Additionally, autophagy after ONC is regulated by ROS and Nrf2. Visual function in mice after ONC injury was partially recovered through the reduction of Zn2+, achieved by using a Zn2+ specific chelator N,N,N',N'-tetrakis-(2-Pyridylmethyl) ethylenediamine (TPEN) or through CKO mice. Overall, our data reveal the crosstalk between Zn2+, ROS, Nrf2 and autophagy following ONC injury. This study verified that TPEN or knocking out ZnT-3 in ACs is a promising therapeutic option for the treatment of optic nerve damage and elucidated the postsynaptic molecular mechanism of Zn2+-triggered damage to RGCs after ONC injury.
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Affiliation(s)
- Caiqing Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Jiaxu Han
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Siting Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Canying Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Qi Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Jiahui Tang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Zhe Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Jinpeng Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Yuze Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Yehong Zhuo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China.
| | - Yiqing Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China.
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He W, Mu X, Wu X, Liu Y, Deng J, Liu Y, Han F, Nie X. The cGAS-STING pathway: a therapeutic target in diabetes and its complications. BURNS & TRAUMA 2024; 12:tkad050. [PMID: 38312740 PMCID: PMC10838060 DOI: 10.1093/burnst/tkad050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/22/2023] [Accepted: 10/09/2023] [Indexed: 02/06/2024]
Abstract
Diabetic wound healing (DWH) represents a major complication of diabetes where inflammation is a key impediment to proper healing. The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway has emerged as a central mediator of inflammatory responses to cell stress and damage. However, the contribution of cGAS-STING activation to impaired healing in DWH remains understudied. In this review, we examine the evidence that cGAS-STING-driven inflammation is a critical factor underlying defective DWH. We summarize studies revealing upregulation of the cGAS-STING pathway in diabetic wounds and discuss how this exacerbates inflammation and senescence and disrupts cellular metabolism to block healing. Partial pharmaceutical inhibition of cGAS-STING has shown promise in damping inflammation and improving DWH in preclinical models. We highlight key knowledge gaps regarding cGAS-STING in DWH, including its relationships with endoplasmic reticulum stress and metal-ion signaling. Elucidating these mechanisms may unveil new therapeutic targets within the cGAS-STING pathway to improve healing outcomes in DWH. This review synthesizes current understanding of how cGAS-STING activation contributes to DWH pathology and proposes future research directions to exploit modulation of this pathway for therapeutic benefit.
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Affiliation(s)
- Wenjie He
- Key Lab of the Basic Pharmacology of the Ministry of Education, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
- College of Pharmacy, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
| | - Xingrui Mu
- Key Lab of the Basic Pharmacology of the Ministry of Education, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
- College of Pharmacy, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
| | - Xingqian Wu
- Key Lab of the Basic Pharmacology of the Ministry of Education, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
- College of Pharmacy, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
| | - Ye Liu
- Key Lab of the Basic Pharmacology of the Ministry of Education, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
- College of Pharmacy, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
| | - Junyu Deng
- Key Lab of the Basic Pharmacology of the Ministry of Education, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
- College of Pharmacy, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
| | - Yiqiu Liu
- Key Lab of the Basic Pharmacology of the Ministry of Education, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
- College of Pharmacy, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
| | - Felicity Han
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Xuqiang Nie
- Key Lab of the Basic Pharmacology of the Ministry of Education, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
- College of Pharmacy, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
- Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, No. 6 Xuefu West Road, Xinpu New District, Zunyi 563006, China
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5
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Coupland CA, Naylor-Adamson L, Booth Z, Price TW, Gil HM, Firth G, Avery M, Ahmed Y, Stasiuk GJ, Calaminus SDJ. Platelet zinc status regulates prostaglandin-induced signaling, altering thrombus formation. J Thromb Haemost 2023; 21:2545-2558. [PMID: 37210073 DOI: 10.1016/j.jtha.2023.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 04/24/2023] [Accepted: 05/07/2023] [Indexed: 05/22/2023]
Abstract
BACKGROUND Approximately 17.3% of the global population exhibits an element of zinc (Zn2+) deficiency. One symptom of Zn2+ deficiency is increased bleeding through impaired hemostasis. Platelets are crucial to hemostasis and are inhibited by endothelial-derived prostacyclin (prostaglandin I2 [PGI2]), which signals via adenylyl cyclase (AC) and cyclic adenosine monophosphate signaling. In other cell types, Zn2+ modulates cyclic adenosine monophosphate concentrations by changing AC and/or phosphodiesterase activity. OBJECTIVES To investigate if Zn2+ can modulate platelet PGI2 signaling. METHODS Platelet aggregation, spreading, and western blotting assays with Zn2+ chelators and cyclic nucleotide elevating agents were performed in washed platelets and platelet-rich plasma conditions. In vitro thrombus formation with various Zn2+ chelators and PGI2 was assessed in whole blood. RESULTS Incubation of whole blood or washed platelets with Zn2+ chelators caused either embolization of preformed thrombi or reversal of platelet spreading, respectively. To understand this effect, we analyzed resting platelets and identified that incubation with Zn2+ chelators elevated pVASPser157, a marker of PGI2 signaling. In agreement that Zn2+ affects PGI2 signaling, addition of the AC inhibitor SQ22536 blocked Zn2+ chelation-induced platelet spreading reversal, while addition of Zn2+ blocked PGI2-mediated platelet reversal. Moreover, Zn2+ specifically blocked forskolin-mediated AC reversal of platelet spreading. Finally, PGI2 inhibition of platelet aggregation and in vitro thrombus formation was potentiated in the presence of low doses of Zn2+ chelators, increasing its effectiveness in inducing platelet inhibition. CONCLUSION Zn2+ chelation potentiates platelet PGI2 signaling, elevating PGI2's ability to prevent effective platelet activation, aggregation, and thrombus formation.
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Affiliation(s)
- Charlie A Coupland
- Centre for Biomedicine, Hull York Medical School, University of Hull, Hull, UK
| | | | - Zoe Booth
- Centre for Biomedicine, Hull York Medical School, University of Hull, Hull, UK
| | - Thomas W Price
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Helio M Gil
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - George Firth
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Michelle Avery
- Centre for Biomedicine, Hull York Medical School, University of Hull, Hull, UK
| | - Yusra Ahmed
- Centre for Biomedicine, Hull York Medical School, University of Hull, Hull, UK
| | - Graeme J Stasiuk
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Simon D J Calaminus
- Centre for Biomedicine, Hull York Medical School, University of Hull, Hull, UK.
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Payen S, Rrodriguez JA, Segura M, Gottschalk M. Laminin-binding protein of Streptococcus suis serotype 2 influences zinc acquisition and cytokine responses. Vet Res 2023; 54:1. [PMID: 36604750 PMCID: PMC9817373 DOI: 10.1186/s13567-022-01128-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/08/2022] [Indexed: 01/07/2023] Open
Abstract
Streptococcus suis serotype 2 is an important bacterial pathogen of swine, responsible for substantial economic losses to the swine industry worldwide. The knowledge on the pathogenesis of the infection caused by S. suis is still poorly known. It has been previously described that S. suis possesses at least one lipoprotein with double laminin and zinc (Zn)-binding properties, which was described in the literature as either laminin-binding protein (Lmb, as in the current study), lipoprotein 103, CDS 0330 or AdcAII. In the present study, the role of the Lmb in the pathogenesis of the infection caused by S. suis serotype 2 was dissected. Using isogenic mutants, results showed that Lmb does not play an important role in the laminin-binding activity of S. suis, even when clearly exposed at the bacterial surface. In addition, the presence of this lipoprotein does not influence bacterial adhesion to and invasion of porcine respiratory epithelial and brain endothelial cells and it does not increase the susceptibility of S. suis to phagocytosis. On the other hand, the Lmb was shown to play an important role as cytokine activator when tested in vitro with dendritic cells. Finally, this lipoprotein plays a critical role in Zn acquisition from the host environment allowing bacteria to grow in vivo. The significant lower virulence of the Lmb defective mutant may be related to a combination of a lower bacterial survival due to the incapacity to acquire Zn from their surrounding milieu and a reduced cytokine activation.
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Affiliation(s)
- Servane Payen
- grid.14848.310000 0001 2292 3357Research Group On Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2 Canada
| | - Jesús Aranda Rrodriguez
- grid.7080.f0000 0001 2296 0625Department de Genètica I Microbiologia, Universitat Autónoma de Barcelona (UAB), Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain
| | - Mariela Segura
- grid.14848.310000 0001 2292 3357Research Group On Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2 Canada
| | - Marcelo Gottschalk
- grid.14848.310000 0001 2292 3357Research Group On Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2 Canada
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Zhang SY, Liang JJ, Liu YQ. Excessive Zinc Ion Caused PC12 Cell Death Correlating with Inhibition of NOS and Increase of RAGE in Cells. Cell Biochem Biophys 2022; 80:755-761. [PMID: 36068383 DOI: 10.1007/s12013-022-01093-1] [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: 08/30/2021] [Accepted: 08/24/2022] [Indexed: 11/03/2022]
Abstract
Zinc ion (Zn2+) is an important functional factor; however, excessive Zn2+ can be toxic. To understand the neurotoxicity of excessive Zn2+ and the underlying mechanism, PC12 cells were treated with excessive Zn2+ and Zn2+ plus N, N, N', N'-Tetrakisethylenediamine (TPEN), a zinc ion chelator agent. Trypan blue and 3-(4,5-dimethyl-2- thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, thiazolyl blue tetrazolium bromide (MTT) assays were used to test cell viability; the relative kits were used to detect the activity of NOS synthase and the content of the receptor for advanced glycation end product (RAGE) in cells. We observed that excessive zinc caused PC12 cell damage and that TPEN partially reversed cell damage caused by excessive zinc. In addition, excessive zinc decreased total nitric oxide synthase (TNOS) activity in cells, in which constitutive nitric oxide synthase (cNOS) activity was significantly reduced; however, inducible nitric oxide synthase (iNOS) activity was extremely promoted. Moreover, excessive zinc upregulated the expression of RAGE, and TPEN effectively reversed the increase in RAGE induced by excessive zinc ions. Therefore, we concluded that excessive zinc caused PC12 cell damage, correlating with the inhibition of NOS and increase of RAGE induced in cells.
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Affiliation(s)
- Sai-Ya Zhang
- College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Jing-Jing Liang
- College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Yan-Qiang Liu
- College of Life Sciences, Nankai University, Tianjin, 300071, China.
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8
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Thein HSS, Hashimoto K, Kawashima N, Noda S, Okiji T. Evaluation of the anti-inflammatory effects of surface-reaction-type pre-reacted glass-ionomer filler containing root canal sealer in lipopolysaccharide-stimulated RAW264.7 macrophages. Dent Mater J 2021; 41:150-158. [PMID: 34602587 DOI: 10.4012/dmj.2021-139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A prototype surface-reaction-type pre-reacted glass-ionomer (S-PRG) filler containing root canal sealer (S-PRG sealer) exhibits bioactive potential by releasing multiple ions. This study explored the suppressive effects and modes of action of S-PRG sealer extracts on proinflammatory cytokine expression in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Expression of proinflammatory cytokines was evaluated by RT-qPCR and ELISA. Expression of phosphorylated nuclear factor-kappa B (p-NF-kB) p65 was evaluated by western blotting. S-PRG sealer extracts significantly downregulated mRNA expression levels of interleukin (IL)-1α, IL-6, and TNF-α in LPS-stimulated RAW264.7 cells; the extracts also reduced the levels of IL-6 protein and p-NF-kB. In order to verify that Zn2+ was responsible for downregulation of proinflammatory cytokine expression, N,N,N',N'-tetrakis(2-pyridylmethyl) ethylenediamine (TPEN) was used as a heavy metal chelator with strong affinity for Zn2+. These effects were mitigated by TPEN. The application of ZnCl2 reproduced the actions of S-PRG sealer extracts. These data suggest that S-PRG sealer has anti-inflammatory potential involving heavy metal ions such as Zn2+.
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Affiliation(s)
- Htoo Shwe Sin Thein
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University.,Department of Paediatric Dentistry, University of Dental Medicine Mandalay
| | - Kentaro Hashimoto
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Nobuyuki Kawashima
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Sonoko Noda
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Takashi Okiji
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
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Redox signaling through zinc activates the radiation response in Deinococcus bacteria. Sci Rep 2021; 11:4528. [PMID: 33633226 PMCID: PMC7907104 DOI: 10.1038/s41598-021-84026-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 02/11/2021] [Indexed: 02/06/2023] Open
Abstract
Deinococcus bacteria are extremely resistant to radiation and other DNA damage- and oxidative stress-generating conditions. An efficient SOS-independent response mechanism inducing expression of several DNA repair genes is essential for this resistance, and is controlled by metalloprotease IrrE that cleaves and inactivates transcriptional repressor DdrO. Here, we identify the molecular signaling mechanism that triggers DdrO cleavage. We show that reactive oxygen species (ROS) stimulate the zinc-dependent metalloprotease activity of IrrE in Deinococcus. Sudden exposure of Deinococcus to zinc excess also rapidly induces DdrO cleavage, but is not accompanied by ROS production and DNA damage. Further, oxidative treatment leads to an increase of intracellular free zinc, indicating that IrrE activity is very likely stimulated directly by elevated levels of available zinc ions. We conclude that radiation and oxidative stress induce changes in redox homeostasis that result in IrrE activation by zinc in Deinococcus. We propose that a part of the zinc pool coordinated with cysteine thiolates is released due to their oxidation. Predicted regulation systems involving IrrE- and DdrO-like proteins are present in many bacteria, including pathogens, suggesting that such a redox signaling pathway including zinc as a second messenger is widespread and participates in various stress responses.
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Abstract
Protein-RNA interactions have crucial roles in various cellular activities, which, when dysregulated, can lead to a range of human diseases. The identification of small molecules that target the interaction between RNA-binding proteins (RBPs) and RNA is progressing rapidly and represents a novel strategy for the discovery of chemical probes that facilitate understanding of the cellular functions of RBPs and of therapeutic agents with new mechanisms of action. In this Review, I present a current overview of targeting emerging RBPs using small-molecule inhibitors and recent progress in this burgeoning field. Small-molecule inhibitors that were reported for three representative emerging classes of RBPs, the microRNA-binding protein LIN28, the single-stranded or double-stranded RNA-binding Toll-like receptors and the CRISPR-associated (Cas) proteins, are highlighted from a medicinal-chemistry and chemical-biology perspective. However, although this field is burgeoning, challenges remain in the discovery and characterization of small-molecule inhibitors of RBPs.
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11
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Wozniak KL, Bainbridge RE, Summerville DW, Tembo M, Phelps WA, Sauer ML, Wisner BW, Czekalski ME, Pasumarthy S, Hanson ML, Linderman MB, Luu CH, Boehm ME, Sanders SM, Buckley KM, Bain DJ, Nicotra ML, Lee MT, Carlson AE. Zinc protection of fertilized eggs is an ancient feature of sexual reproduction in animals. PLoS Biol 2020; 18:e3000811. [PMID: 32735558 PMCID: PMC7423145 DOI: 10.1371/journal.pbio.3000811] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 08/12/2020] [Accepted: 07/10/2020] [Indexed: 01/04/2023] Open
Abstract
One of the earliest and most prevalent barriers to successful reproduction is polyspermy, or fertilization of an egg by multiple sperm. To prevent these supernumerary fertilizations, eggs have evolved multiple mechanisms. It has recently been proposed that zinc released by mammalian eggs at fertilization may block additional sperm from entering. Here, we demonstrate that eggs from amphibia and teleost fish also release zinc. Using Xenopus laevis as a model, we document that zinc reversibly blocks fertilization. Finally, we demonstrate that extracellular zinc similarly disrupts early embryonic development in eggs from diverse phyla, including Cnidaria, Echinodermata, and Chordata. Our study reveals that a fundamental strategy protecting human eggs from fertilization by multiple sperm may have evolved more than 650 million years ago.
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Affiliation(s)
- Katherine L. Wozniak
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Rachel E. Bainbridge
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Dominique W. Summerville
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Maiwase Tembo
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Wesley A. Phelps
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Monica L. Sauer
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Bennett W. Wisner
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Madelyn E. Czekalski
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Srikavya Pasumarthy
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Meghan L. Hanson
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Melania B. Linderman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Catherine H. Luu
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Madison E. Boehm
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Steven M. Sanders
- Department of Surgery and Immunology, Thomas E. Starzl Transplantation Institute, and Center for Evolutionary Biology and Medicine, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, United States of America
| | - Katherine M. Buckley
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
| | - Daniel J. Bain
- Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Matthew L. Nicotra
- Department of Surgery and Immunology, Thomas E. Starzl Transplantation Institute, and Center for Evolutionary Biology and Medicine, University of Pittsburgh School of Medicine, Pittsburgh Pennsylvania, United States of America
| | - Miler T. Lee
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Anne E. Carlson
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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12
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Alluri K, Nair KPM, Kotturu SK, Ghosh S. Transcriptional Regulation of Zinc Transporters in Human Osteogenic Sarcoma (Saos-2) Cells to Zinc Supplementation and Zinc Depletion. Biol Trace Elem Res 2020; 194:360-367. [PMID: 31325026 DOI: 10.1007/s12011-019-01807-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 06/28/2019] [Indexed: 10/26/2022]
Abstract
Bone is a passive storage organ for zinc, which contains about 30% of the total body zinc. However, during extreme zinc deficiency, only a small fraction of zinc is released in contrast to other tissues where zinc is released like monocytes or conserved, e.g., skeletal muscle. Zinc plays an important role in bone tissue remodeling. Zinc homeostasis is regulated by several zinc transporters (ZnTs) and importers (ZIPs), but their expression dynamics concerning zinc status of bone cells is not well understood. The study aimed to elucidate the effects of zinc supplementation and depletion on the transcript levels of various zinc transporters. Saos-2, a human osteoblastic cell line, was used as representative bone tissue. Zinc sulfate was used for simulating sufficient zinc status whereas TPEN, a zinc chelator, was used to simulate zinc-deficient state. Expression of various transcripts was measured by qRT-PCR. Subcellular localization of ZnT-1 was carried out by immunofluorescent microscopy, and Western Blotting was carried out to measure the expression of ZnT-1 at the protein level. Among the export transporters the transcript levels of MT, ZnT-1 showed higher levels in zinc sufficient and lower levels in TPEN treated cells. Expression of ZnT-4 was decreased under both the conditions. ZIP-6 and ZIP-13 were downregulated in zinc sufficiency, and ZIP-10 upregulated probably to prevent an excess zinc accumulation in bone cells. Further, ZnT-1 was found to be localized in the nuclear region of SaOS-2 cells. ZnT-1, ZnT-4, ZIP-6, ZIP-11, ZIP-10, and ZIP-13 along with MT may be responsible for maintaining bone zinc homeostasis.
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Affiliation(s)
- Kiran Alluri
- Molecular Biology Division, ICMR-National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, 500007, India
| | - Krishna Pillay Madhavan Nair
- Micronutrient Division, Micronutrient Research Group, ICMR-National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, 500007, India.
| | - Sandeep Kumar Kotturu
- Molecular Biology Division, ICMR-National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, 500007, India
| | - Sudip Ghosh
- Molecular Biology Division, ICMR-National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, 500007, India.
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13
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Kar M, Khan NA, Panwar A, Bais SS, Basak S, Goel R, Sopory S, Medigeshi GR. Zinc Chelation Specifically Inhibits Early Stages of Dengue Virus Replication by Activation of NF-κB and Induction of Antiviral Response in Epithelial Cells. Front Immunol 2019; 10:2347. [PMID: 31632411 PMCID: PMC6779808 DOI: 10.3389/fimmu.2019.02347] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 09/17/2019] [Indexed: 12/18/2022] Open
Abstract
Zinc is an essential micronutrient which regulates diverse physiological functions and has been shown to play a crucial role in viral infections. Zinc has a necessary role in the replication of many viruses, however, antiviral action of zinc has also been demonstrated in in vitro infection models most likely through induction of host antiviral responses. Therefore, depending on the host machinery that the virus employs at different stages of infection, zinc may either facilitate, or inhibit virus infection. In this study, we show that zinc plays divergent roles in rotavirus and dengue virus infections in epithelial cells. Dengue virus infection did not perturb the epithelial barrier functions despite the release of virus from the basolateral surface whereas rotavirus infection led to disruption of epithelial junctions. In rotavirus infection, zinc supplementation post-infection did not block barrier disruption suggesting that zinc does not affect rotavirus life-cycle or protects epithelial barriers post-infection suggesting the involvement of cellular pathways in the beneficial effect of zinc supplementation in enteric infections. Zinc depletion by N,N,N',N'-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN) inhibited dengue virus and Japanese encephalitis virus (JEV) infection but had no effect on rotavirus. Time-of-addition experiments suggested that zinc chelation affected both early and late stages of dengue virus infectious cycle and zinc chelation abrogated dengue virus RNA replication. We show that transient zinc chelation induces ER stress and antiviral response by activating NF-kappaB leading to induction of interferon signaling. These results suggest that modulation of zinc homeostasis during virus infection could be a component of host antiviral response and altering zinc homeostasis may act as a potent antiviral strategy against flaviviruses.
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Affiliation(s)
- Meenakshi Kar
- Clinical and Cellular Virology Lab, Translational Health Science and Technology Institute, Faridabad, India
| | - Naseem Ahmed Khan
- Clinical and Cellular Virology Lab, Translational Health Science and Technology Institute, Faridabad, India
| | - Aleksha Panwar
- Clinical and Cellular Virology Lab, Translational Health Science and Technology Institute, Faridabad, India
| | - Sachendra S Bais
- Systems Immunology Laboratory, National Institute of Immunology, New Delhi, India
| | - Soumen Basak
- Systems Immunology Laboratory, National Institute of Immunology, New Delhi, India
| | - Renu Goel
- Drug Discovery Research Centre, Translational Health Science and Technology Institute, Faridabad, India
| | - Shailaja Sopory
- Pediatric Biology Centre, Translational Health Science and Technology Institute, Faridabad, India
| | - Guruprasad R Medigeshi
- Clinical and Cellular Virology Lab, Translational Health Science and Technology Institute, Faridabad, India
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14
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Ren L, Dowlatshahi Pour M, Malmberg P, Ewing AG. Altered Lipid Composition of Secretory Cells Following Exposure to Zinc Can Be Correlated to Changes in Exocytosis. Chemistry 2019; 25:5406-5411. [PMID: 30762272 DOI: 10.1002/chem.201900010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Indexed: 12/20/2022]
Abstract
A micromolar concentration of zinc has been shown to significantly change the dynamics of exocytosis as well as the vesicle contents in a model cell line, providing direct evidence that zinc regulates neurotransmitter release. To provide insight into how zinc modulates these exocytotic processes, neurotransmitter release and vesicle content were compared with single cell amperometry and intracellular impact vesicle cytometry with a range of zinc concentrations. Additionally, time-of-flight secondary ion mass spectrometry (ToF-SIMS) images of lipid distributions in the cell membrane after zinc treatment correlate to changes in exocytosis. By combining electrochemical techniques and mass spectrometry imaging, we proposed a mechanism by which zinc changes the fusion pore and the rate of neurotransmitter release by changing lipid distributions and results in the modulation of synaptic strength and plasticity.
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Affiliation(s)
- Lin Ren
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
| | - Masoumeh Dowlatshahi Pour
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
- Chemical Imaging Infrastructure, CII, University of Gothenburg and Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
| | - Per Malmberg
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
- Chemical Imaging Infrastructure, CII, University of Gothenburg and Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
| | - Andrew G Ewing
- Chemical Imaging Infrastructure, CII, University of Gothenburg and Chalmers University of Technology, Kemivägen 10, 41296, Gothenburg, Sweden
- Department of Chemistry and Molecular Biology, University of Gothenburg, Kemivägen 10, 41296, Gothenburg, Sweden
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15
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Sullivan JA, Zhang XL, Sullivan AP, Vose LR, Moghadam AA, Fried VA, Stanton PK. Zinc enhances hippocampal long-term potentiation at CA1 synapses through NR2B containing NMDA receptors. PLoS One 2018; 13:e0205907. [PMID: 30485271 PMCID: PMC6261414 DOI: 10.1371/journal.pone.0205907] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 10/03/2018] [Indexed: 01/16/2023] Open
Abstract
The role of zinc (Zn2+), a modulator of N-methyl-D-aspartate (NMDA) receptors, in regulating long-term synaptic plasticity at hippocampal CA1 synapses is poorly understood. The effects of exogenous application of Zn2+ and of chelation of endogenous Zn2+ were examined on long-term potentiation (LTP) of stimulus-evoked synaptic transmission at Schaffer collateral (SCH) synapses in field CA1 of mouse hippocampal slices using whole-cell patch clamp and field recordings. Low micromolar concentrations of exogenous Zn2+ enhanced the induction of LTP, and this effect required activation of NMDA receptors containing NR2B subunits. Zn2+ elicited a selective increase in NMDA/NR2B fEPSPs, and removal of endogenous Zn2+ with high-affinity Zn2+ chelators robustly reduced the magnitude of stimulus-evoked LTP. Taken together, our data show that Zn2+ at physiological concentrations enhances activation of NMDA receptors containing NR2B subunits, and that this effect enhances the magnitude of LTP.
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Affiliation(s)
- John A. Sullivan
- Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States of America
- * E-mail:
| | - Xiao-lei Zhang
- Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States of America
| | - Arthur P. Sullivan
- Psychology & Education, Touro School of Health Sciences, New York, New York, United States of America
| | - Linnea R. Vose
- Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States of America
| | - Alexander A. Moghadam
- Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States of America
| | - Victor A. Fried
- Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States of America
| | - Patric K. Stanton
- Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States of America
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16
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Morgan MT, Yang B, Harankhedkar S, Nabatilan A, Bourassa D, McCallum AM, Sun F, Wu R, Forest CR, Fahrni CJ. Stabilization of Aliphatic Phosphines by Auxiliary Phosphine Sulfides Offers Zeptomolar Affinity and Unprecedented Selectivity for Probing Biological Cu I. Angew Chem Int Ed Engl 2018; 57:9711-9715. [PMID: 29885022 PMCID: PMC6105516 DOI: 10.1002/anie.201804072] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/01/2018] [Indexed: 01/06/2023]
Abstract
Full elucidation of the functions and homeostatic pathways of biological copper requires tools that can selectively recognize and manipulate this trace nutrient within living cells and tissues, where it exists primarily as CuI . Buffered at attomolar concentrations, intracellular CuI is, however, not readily accessible to commonly employed amine and thioether-based chelators. Herein, we reveal a chelator design strategy in which phosphine sulfides aid in CuI coordination while simultaneously stabilizing aliphatic phosphine donors, producing a charge-neutral ligand with low-zeptomolar dissociation constant and 1017 -fold selectivity for CuI over ZnII , FeII , and MnII . As illustrated by reversing ATP7A trafficking in cells and blocking long-term potentiation of neurons in mouse hippocampal brain tissue, the ligand is capable of intercepting copper-dependent processes. The phosphine sulfide-stabilized phosphine (PSP) design approach, which confers resistance towards protonation, dioxygen, and disulfides, could be readily expanded towards ligands and probes with tailored properties for exploring CuI in a broad range of biological systems.
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Affiliation(s)
- M. Thomas Morgan
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Bo Yang
- Prof. Dr. C.R. Forest, Dr. B. Yang G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology 315 Ferst Drive, Atlanta, GA 30332, USA,
| | - Shefali Harankhedkar
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Arielle Nabatilan
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Daisy Bourassa
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Adam M. McCallum
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Fangxu Sun
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Ronghu Wu
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
| | - Craig R. Forest
- Prof. Dr. C.R. Forest, Dr. B. Yang G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology 315 Ferst Drive, Atlanta, GA 30332, USA,
| | - Christoph J. Fahrni
- Prof. Dr. C.J. Fahrni, Prof. Dr. R. Wu, Dr. M.T. Morgan, Dr. S Harankhedkar, A. Nabatilan, Dr. D. Bourassa, Dr. A.M. McCallum, F. Sun School of Chemistry and Biochemistry, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology 901 Atlantic Drive, Atlanta, GA 30332, USA,
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17
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Morgan MT, Yang B, Harankhedkar S, Nabatilan A, Bourassa D, McCallum AM, Sun F, Wu R, Forest CR, Fahrni CJ. Stabilization of Aliphatic Phosphines by Auxiliary Phosphine Sulfides Offers Zeptomolar Affinity and Unprecedented Selectivity for Probing Biological Cu
I. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- M. Thomas Morgan
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Bo Yang
- G. W. Woodruff School of Mechanical Engineering Georgia Institute of Technology 315 Ferst Drive Atlanta GA 30332 USA
| | - Shefali Harankhedkar
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Arielle Nabatilan
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Daisy Bourassa
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Adam M. McCallum
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Fangxu Sun
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Ronghu Wu
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
| | - Craig R. Forest
- G. W. Woodruff School of Mechanical Engineering Georgia Institute of Technology 315 Ferst Drive Atlanta GA 30332 USA
| | - Christoph J. Fahrni
- School of Chemistry and Biochemistry Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
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18
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Zinc depletion promotes apoptosis-like death in drug-sensitive and antimony-resistance Leishmania donovani. Sci Rep 2017; 7:10488. [PMID: 28874760 PMCID: PMC5585245 DOI: 10.1038/s41598-017-10041-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 07/25/2017] [Indexed: 12/28/2022] Open
Abstract
Micronutrients are essential for survival and growth for all the organisms including pathogens. In this manuscript, we report that zinc (Zn) chelator N,N,N’,N’-tetrakis(2-pyridinylmethyl)-1,2-ethylenediamine (TPEN) affects growth and viability of intracellular pathogen Leishmania donovani (LD) by a concentration and time dependent manner. Simultaneous addition of zinc salt reverses the effect of TPEN. Further experiments provide evidence of apoptosis-like death of the parasite due to Zn-depletion. TPEN treatment enhances caspase-like activity suggesting increase in apoptosis-like events in LD. Specific inhibitors of cathepsin B and Endoclease G block TPEN-induced leishmanial death. Evidences show involvement of reactive oxygen species (ROS) potentially of extra-mitochondrial origin in TPEN-induced LD death. Pentavalent antimonials remained the prime source of treatment against leishmaniasis for several decades; however, antimony-resistant Leishmania is now common source of the disease. We also reveal that Zn-depletion can promote apoptosis-like death in antimony-resistant parasites. In summary, we present a new finding about the role of zinc in the survival of drug sensitive and antimony-resistant LD.
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19
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Tedde V, Rosini R, Galeotti CL. Zn2+ Uptake in Streptococcus pyogenes: Characterization of adcA and lmb Null Mutants. PLoS One 2016; 11:e0152835. [PMID: 27031880 PMCID: PMC4816340 DOI: 10.1371/journal.pone.0152835] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 02/29/2016] [Indexed: 01/29/2023] Open
Abstract
An effective regulation of metal ion homeostasis is essential for the growth of microorganisms in any environment and in pathogenic bacteria is strongly associated with their ability to invade and colonise their hosts. To gain a better insight into zinc acquisition in Group A Streptococcus (GAS) we characterized null deletion mutants of the adcA and lmb genes of Streptococcus pyogenes strain MGAS5005 encoding the orthologues of AdcA and AdcAII, the two surface lipoproteins with partly redundant roles in zinc homeostasis in Streptococcus pneumoniae. Null adcA and lmb mutants were analysed for their capability to grow in zinc-depleted conditions and were found to be more susceptible to zinc starvation, a phenotype that could be rescued by the addition of Zn2+ ions to the growth medium. Expression of AdcA, Lmb and HtpA, the polyhistidine triad protein encoded by the gene adjacent to lmb, during growth under conditions of limited zinc availability was examined by Western blot analysis in wild type and null mutant strains. In the wild type strain, AdcA was always present with little variation in expression levels between conditions of excess or limited zinc availability. In contrast, Lmb and HtpA were expressed at detectable levels only during growth in the presence of low zinc concentrations or in the null adcA mutant, when expression of lmb is required to compensate for the lack of adcA expression. In the latter case, Lmb and HtpA were overexpressed by several fold, thus indicating that also in GAS AdcA is a zinc-specific importer and, although it shares this function with Lmb, the two substrate-binding proteins do not show fully overlapping roles in zinc homeostasis.
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Affiliation(s)
- Vittorio Tedde
- Research Centre, GlaxoSmithKline Vaccines S.r.l., Siena, Italy
| | - Roberto Rosini
- Research Centre, GlaxoSmithKline Vaccines S.r.l., Siena, Italy
| | - Cesira L. Galeotti
- Research Centre, GlaxoSmithKline Vaccines S.r.l., Siena, Italy
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
- * E-mail:
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20
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Morey JR, McDevitt CA, Kehl-Fie TE. Host-imposed manganese starvation of invading pathogens: two routes to the same destination. Biometals 2015; 28:509-19. [PMID: 25836716 PMCID: PMC4430393 DOI: 10.1007/s10534-015-9850-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/24/2015] [Indexed: 01/07/2023]
Abstract
During infection invading pathogens must acquire all essential nutrients, including first row transition metals, from the host. To combat invaders, the host exploits this fact and restricts the availability of these nutrients using a defense mechanism known as nutritional immunity. While iron sequestration is the most well-known aspect of this defense, recent work has revealed that the host restricts the availability of other essential elements, notably manganese (Mn), during infection. Furthermore, these studies have revealed that the host utilizes multiple strategies that extend beyond metal sequestration to prevent bacteria from obtaining these metals. This review will discuss the mechanisms by which bacteria attempt to obtain the essential first row transition metal ion Mn during infection, and the approaches utilized by the host to prevent this occurrence. In addition, this review will discuss the impact of host-imposed Mn starvation on invading bacteria.
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Affiliation(s)
- Jacqueline R. Morey
- Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Christopher A. McDevitt
- Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Thomas E. Kehl-Fie
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana IL, USA
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21
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Tanaka N, Fujiwara T, Tomioka R, Krämer U, Kawachi M, Maeshima M. Characterization of the histidine-rich loop of Arabidopsis vacuolar membrane zinc transporter AtMTP1 as a sensor of zinc level in the cytosol. PLANT & CELL PHYSIOLOGY 2015; 56:510-519. [PMID: 25516571 DOI: 10.1093/pcp/pcu194] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The vacuolar Zn(2+)/H(+) antiporter of Arabidopsis thaliana, AtMTP1, has a long cytosolic histidine-rich loop. A mutated AtMTP1 in which the first half of the loop (His-half) was deleted exhibited a 11-fold higher transport velocity in yeast cells. Transgenic lines overexpressing the His-half-deleted AtMTP1 in the loss-of-function mutant were evaluated for growth and metal content in the presence of various zinc concentrations. These overexpressing lines (35S-AtMTP1 and 35S-His-half lines) showed high tolerance to excess concentrations of zinc at 150 µM, as did the wild type, compared with the loss-of-function line. The His-half AtMTP1 transported cobalt in a heterologous expression assay in yeast, but the cumulative amount of cobalt in 35S-His-half plants was not increased. Moreover, the accumulation of calcium and iron was not changed in plants. Under zinc-deficient conditions, growth of 35S-His-half lines was markedly suppressed. Under the same conditions, the 35S-His-half lines accumulated larger amounts of zinc in roots and smaller amounts of zinc in shoots compared with the other lines, suggesting an abnormal accumulation of zinc in the roots of 35S-His-half lines. As a result, the shoots may exhibit zinc deficiency. Taken together, these results suggest that the His-loop acts as a sensor of cytosolic zinc to maintain an essential level in the cytosol and that the dysfunction of the loop results in an uncontrolled accumulation of zinc in the vacuoles of root cells.
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Affiliation(s)
- Natsuki Tanaka
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
| | - Takashi Fujiwara
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
| | - Rie Tomioka
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
| | - Ute Krämer
- Department of Plant Physiology, Ruhr-University Bochum, D-44801 Bochum, Germany
| | - Miki Kawachi
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
| | - Masayoshi Maeshima
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan
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Figueroa JAL, Vignesh KS, Deepe GS, Caruso J. Selectivity and specificity of small molecule fluorescent dyes/probes used for the detection of Zn2+ and Ca2+ in cells. Metallomics 2014; 6:301-15. [PMID: 24356796 DOI: 10.1039/c3mt00283g] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Fluorescent dyes are widely used in the detection of labile (free or exchangeable) Zn(2+) and Ca(2+) in living cells. However, their specificity over other cations and selectivity for detection of labile vs. protein-bound metal in cells remains unclear. We characterized these important properties for commonly used Zn(2+) and Ca(2+) dyes in a cellular environment. By tracing the fluorescence emission signal along with UV-Vis and size exclusion chromatography-inductively coupled plasma mass spectrometry (SEC-ICP-MS) in tandem, we demonstrated that among the dyes used for Zn(2+), Zinpyr-1 fluoresces in the low molecular mass (LMM) region containing labile Zn(2+), but also fluoresces in different molecular mass regions where zinc ion is detected. However, FluoZin™-3 AM, Newport Green™ DCF and Zinquin ethyl ester display weak fluorescence, lack of metal specificity and respond strongly in the high molecular mass (HMM) region. Four Ca(2+) dyes were studied in an unperturbed cellular environment, and two of these were tested for binding behavior under an intracellular Ca(2+) release stimulus. A majority of Ca(2+) was in the labile form as tested by SEC-ICP-MS, but the fluorescence from Calcium Green-1™ AM, Oregon Green® 488 BAPTA-1, Fura red™ AM and Fluo-4 NW dyes in cells did not correspond to free Ca(2+) detection. Instead, the dyes showed non-specific fluorescence in the mid- and high-molecular mass regions containing Zn, Fe and Cu. Proteomic analysis of one of the commonly seen fluorescing regions showed the possibility for some dyes to recognize Zn and Cu bound to metallothionein 2. These studies indicate that Zn(2+) and Ca(2+) binding dyes manifest fluorescence responses that are not unique to recognition of labile metals and bind other metals, leading to suboptimal specificity and selectivity.
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Affiliation(s)
- Julio A Landero Figueroa
- Metallomics Research Center, Department of Chemistry, McMicken College of Arts and Sciences, University of Cincinnati, Cincinnati, OH 45221, USA.
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Nygaard SB, Larsen A, Knuhtsen A, Rungby J, Smidt K. Effects of zinc supplementation and zinc chelation on in vitro β-cell function in INS-1E cells. BMC Res Notes 2014; 7:84. [PMID: 24502363 PMCID: PMC3923740 DOI: 10.1186/1756-0500-7-84] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 02/04/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Zinc is essential for the activities of pancreatic β-cells, especially insulin storage and secretion. Insulin secretion leads to co-release of zinc which contributes to the paracrine communication in the pancreatic islets. Zinc-transporting proteins (zinc-regulated transporter, iron-regulated transporter-like proteins [ZIPs] and zinc transporters [ZnTs]) and metal-buffering proteins (metallothioneins, MTs) tightly regulate intracellular zinc homeostasis. The present study investigated how modulation of cellular zinc availability affects β-cell function using INS-1E cells. RESULTS Using INS-1E cells, we found that zinc supplementation and zinc chelation had significant effects on insulin content and insulin secretion. Supplemental zinc within the physiological concentration range induced insulin secretion. Insulin content was reduced by zinc chelation with N,N,N',N-tektrakis(2-pyridylmethyl)-ethylenediamine. The changes in intracellular insulin content following exposure to various concentrations of zinc were reflected by changes in the expression patterns of MT-1A, ZnT-8, ZnT-5, and ZnT-3. Furthermore, high zinc concentrations induced cell necrosis while zinc chelation induced apoptosis. Finally, cell proliferation was sensitive to changes in zinc the concentration. CONCLUSION These results indicate that the β-cell-like function and survival of INS-1E cells are dependent on the surrounding zinc concentrations. Our results suggest that regulation of zinc homeostasis could represent a pharmacological target.
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Affiliation(s)
- Sanne Bjørn Nygaard
- Department of Biomedicine, Centre of Pharmacology and Pharmacotherapy, Health, Aarhus University, Wilhelm Meyers Allé 4, Bld 1240, Aarhus, 8000, Denmark.
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Zheng J, Zhang Y, Xu W, Luo Y, Hao J, Shen XL, Yang X, Li X, Huang K. Zinc protects HepG2 cells against the oxidative damage and DNA damage induced by ochratoxin A. Toxicol Appl Pharmacol 2013; 268:123-31. [DOI: 10.1016/j.taap.2013.01.021] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 01/05/2013] [Accepted: 01/22/2013] [Indexed: 12/23/2022]
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Zhang C, Lu X, Tan Y, Li B, Miao X, Jin L, Shi X, Zhang X, Miao L, Li X, Cai L. Diabetes-induced hepatic pathogenic damage, inflammation, oxidative stress, and insulin resistance was exacerbated in zinc deficient mouse model. PLoS One 2012; 7:e49257. [PMID: 23251339 PMCID: PMC3520990 DOI: 10.1371/journal.pone.0049257] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Accepted: 10/05/2012] [Indexed: 12/31/2022] Open
Abstract
Objectives Zinc (Zn) deficiency often occurs in the patients with diabetes. Effects of Zn deficiency on diabetes-induced hepatic injury were investigated. Methods Type 1 diabetes was induced in FVB mice with multiple low-dose streptozotocin. Hyperglycemic and age-matched control mice were treated with and without Zn chelator, N,N,N′,N′-tetrakis (2-pyridylemethyl) ethylenediamine (TPEN), at 5 mg/kg body-weight daily for 4 months. Hepatic injury was examined by serum alanine aminotransferase (ALT) level and liver histopathological and biochemical changes. Results Hepatic Zn deficiency (lower than control level, p<0.05) was seen in the mice with either diabetes or TPEN treatment and more evident in the mice with both diabetes and TPEN. Zn deficiency exacerbated hepatic injuries, shown by further increased serum ALT, hepatic lipid accumulation, inflammation, oxidative damage, and endoplasmic reticulum stress-related cell death in Diabetes/TPEN group compared to Diabetes alone. Diabetes/TPEN group also showed a significant decrease in nuclear factor-erythroid 2-related factor 2 (Nrf2) expression and transcription action along with significant increases in Akt negative regulators, decrease in Akt and GSK-3β phosphorylation, and increase in nuclear accumulation of Fyn (a Nrf2 negative regulator). In vitro study with HepG2 cells showed that apoptotic effect of TPEN at 0.5–1.0 µM could be completely prevented by simultaneous Zn supplementation at the dose range of 30–50 µM. Conclusions Zn is required for maintaining Akt activation by inhibiting the expression of Akt negative regulators; Akt activation can inhibit Fyn nuclear translocation to export nuclear Nrf2 to cytoplasm for degradation. Zn deficiency significantly enhanced diabetes-induced hepatic injury likely through down-regulation of Nrf2 function.
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Affiliation(s)
- Chi Zhang
- Ruian Center of the Chinese-American Research Institute for Diabetic Complications, The Third Affiliated Hospital of the Wenzhou Medical College, Wenzhou, Zhejiang, People's Republic of China
- The Chinese-American Research Institute for Diabetic Complications, The Wenzhou Medical College, Wenzhou, Zhejiang, People's Republic of China
- Kosair Children Hospital Research Institute, at the Department of Pediatrics of University of Louisville School of Medicine, Louisville, Kentucky, United States of America
| | - Xuemian Lu
- Ruian Center of the Chinese-American Research Institute for Diabetic Complications, The Third Affiliated Hospital of the Wenzhou Medical College, Wenzhou, Zhejiang, People's Republic of China
| | - Yi Tan
- The Chinese-American Research Institute for Diabetic Complications, The Wenzhou Medical College, Wenzhou, Zhejiang, People's Republic of China
- Kosair Children Hospital Research Institute, at the Department of Pediatrics of University of Louisville School of Medicine, Louisville, Kentucky, United States of America
| | - Bing Li
- Kosair Children Hospital Research Institute, at the Department of Pediatrics of University of Louisville School of Medicine, Louisville, Kentucky, United States of America
- The Second Hospital of Jilin University, Changchun, People's Republic of China
| | - Xiao Miao
- Kosair Children Hospital Research Institute, at the Department of Pediatrics of University of Louisville School of Medicine, Louisville, Kentucky, United States of America
- The Second Hospital of Jilin University, Changchun, People's Republic of China
| | - Litai Jin
- The Chinese-American Research Institute for Diabetic Complications, The Wenzhou Medical College, Wenzhou, Zhejiang, People's Republic of China
| | - Xue Shi
- Department of Chemistry, University of Louisville, Louisville, Kentucky, United States of America
| | - Xiang Zhang
- Department of Chemistry, University of Louisville, Louisville, Kentucky, United States of America
| | - Lining Miao
- The Second Hospital of Jilin University, Changchun, People's Republic of China
| | - Xiaokun Li
- The Chinese-American Research Institute for Diabetic Complications, The Wenzhou Medical College, Wenzhou, Zhejiang, People's Republic of China
- * E-mail: (XKL); (LC)
| | - Lu Cai
- Ruian Center of the Chinese-American Research Institute for Diabetic Complications, The Third Affiliated Hospital of the Wenzhou Medical College, Wenzhou, Zhejiang, People's Republic of China
- The Chinese-American Research Institute for Diabetic Complications, The Wenzhou Medical College, Wenzhou, Zhejiang, People's Republic of China
- Kosair Children Hospital Research Institute, at the Department of Pediatrics of University of Louisville School of Medicine, Louisville, Kentucky, United States of America
- Departments of Pharmacology and Toxicology, and Radiation Oncology, the University of Louisville, Louisville, Kentucky, United States of America
- * E-mail: (XKL); (LC)
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Spirli C, Locatelli L, Fiorotto R, Morell CM, Fabris L, Pozzan T, Strazzabosco M. Altered store operated calcium entry increases cyclic 3',5'-adenosine monophosphate production and extracellular signal-regulated kinases 1 and 2 phosphorylation in polycystin-2-defective cholangiocytes. Hepatology 2012; 55:856-68. [PMID: 21987453 PMCID: PMC3272110 DOI: 10.1002/hep.24723] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
UNLABELLED Mutations in polycystins (PC1 or PC2/TRPP2) cause progressive polycystic liver disease (PLD). In PC2-defective mice, cyclic 3',5'-adenosine monophosphate/ protein kinase A (cAMP/PKA)-dependent activation of extracellular signal-regulated kinase/ mammalian target of rapamycin (ERK-mTOR) signaling stimulates cyst growth. We investigated the mechanisms connecting PC2 dysfunction to altered Ca(2+) and cAMP production and inappropriate ERK signaling in PC2-defective cholangiocytes. Cystic cholangiocytes were isolated from PC2 conditional-KO (knockout) mice (Pkd2(flox/-) :pCxCreER™; hence, called Pkd2KO) and compared to cholangiocytes from wild-type mice (WT). Our results showed that, compared to WT cells, in PC2-defective cholangiocytes (Pkd2KO), cytoplasmic and ER-Ca(2+) (measured with Fura-2 and Mag-Fluo4) levels are decreased and store-operated Ca(2+) entry (SOCE) is inhibited, whereas the expression of Ca(2+) -sensor stromal interaction molecule 1 (STIM1) and store-operated Ca(2+) channels (e.g., the Orai1 channel) are unchanged. In Pkd2KO cells, ER-Ca(2+) depletion increases cAMP and PKA-dependent ERK1/2 activation and both are inhibited by STIM1 inhibitors or by silencing of adenylyl cyclase type 6 (AC6). CONCLUSION These data suggest that PC2 plays a key role in SOCE activation and inhibits the STIM-dependent activation of AC6 by ER Ca(2+) depletion. In PC2-defective cells, the interaction of STIM-1 with Orai channels is uncoupled, whereas coupling to AC6 is maximized. The resulting overproduction of cAMP, in turn, potently activates the PKA/ERK pathway. PLD, because of PC2 deficiency, represents the first example of human disease linked to the inappropriate activation of store-operated cAMP production.
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Affiliation(s)
- Carlo Spirli
- Dept. of Internal Medicine; Liver Center and Digestive Diseases Section; Yale University; New Haven; USA
- CeLiveR; Ospedali Riuniti di Bergamo; Bergamo, Italy
| | - Luigi Locatelli
- Dept. of Internal Medicine; Liver Center and Digestive Diseases Section; Yale University; New Haven; USA
- CeLiveR; Ospedali Riuniti di Bergamo; Bergamo, Italy
- Dept. of Clinical Medicine and Prevention University of Milan-Bicocca, Monza, Italy
| | - Romina Fiorotto
- Dept. of Internal Medicine; Liver Center and Digestive Diseases Section; Yale University; New Haven; USA
- CeLiveR; Ospedali Riuniti di Bergamo; Bergamo, Italy
| | - Carola M. Morell
- Dept. of Internal Medicine; Liver Center and Digestive Diseases Section; Yale University; New Haven; USA
- Dept. of Clinical Medicine and Prevention University of Milan-Bicocca, Monza, Italy
| | - Luca Fabris
- CeLiveR; Ospedali Riuniti di Bergamo; Bergamo, Italy
- Department of Gastroenterological Sciences, University of Padova, Padova, Italy
| | - Tullio Pozzan
- Consiglio Nazionale delle Ricerche, Neuroscience Institute, Dept. of Biomedical Sciences, University of Padova and Venetian Institute of Molecular Medicine, Padova, Italy
| | - Mario Strazzabosco
- Dept. of Internal Medicine; Liver Center and Digestive Diseases Section; Yale University; New Haven; USA
- CeLiveR; Ospedali Riuniti di Bergamo; Bergamo, Italy
- Dept. of Clinical Medicine and Prevention University of Milan-Bicocca, Monza, Italy
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The neurosteroids, allopregnanolone and progesterone, induce autophagy in cultured astrocytes. Neurochem Int 2011; 60:125-33. [PMID: 22154800 DOI: 10.1016/j.neuint.2011.11.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 11/21/2011] [Accepted: 11/22/2011] [Indexed: 11/23/2022]
Abstract
Recent studies have suggested that neurosteroids such as pregnenolone, progesterone (PG) and their derivatives, have a role in activating autophagy in addition to diverse other functions. In our previous studies, we demonstrated that cellular free Zn(2+) is involved in oxidative stress-induced autophagy and autophagic cell death in astrocytes. In the present study, we examined the possibility that neurosteroids, allopregnanolone (Allo) and PG, also activate autophagy in cultured mouse astrocytes through modulation of intracellular Zn(2+). Exposure of astrocytes to 250 nM Allo or 500 nM PG caused cytosolic vacuoles to appear within a few hours of treatment onset. Live-cell confocal microscopy of astrocytes transfected with red fluorescent protein-conjugated LC3 (RFP-LC3), a marker for autophagic vacuoles (AVs), as well as transmission electron microscopy, revealed that these vacuoles were AVs. In addition, Western blots showed increases in LC3-II levels. Interestingly, mTOR and Akt were concurrently activated, and their blockade further increased LC3-II levels and caused some cell death. These results indicate that co-activation of mTOR and Akt may act to limit neurosteroid-induced autophagy and thus inhibit autophagic cell death. As in other cases of autophagy, cellular Zn(2+) levels increased after treatment with neurosteroids. The neurosteroid-induced increase in LC3-II levels was inhibited by addition of the Zn(2+) chelator TPEN. Both the increase in LC3-II levels and activation of Akt and mTOR by neurosteroids were all mediated by PG receptors, as the effects were blocked by the addition of RU-486, a PG receptor antagonist. Moreover, mutant huntingtin (mHtt) aggregates in GFP-mHttQ74-transfected astrocytes were substantially reduced by neurosteroid treatment, indicating that neurosteroid-induced autophagy may be functional. Present results demonstrate that Allo and PG activate autophagy in astrocytes. Notably, unlike several other autophagy inducers that, in excess, may cause autophagic cell death, Allo and PG are relatively non-toxic, possibly because of concurrent Akt and mTOR activation. Thus, as natural endogenous brain substances, Allo and PG may have a potential as therapeutic agents in neurodegenerative conditions in which abnormal protein aggregates are involved.
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Lee SJ, Cho KS, Kim HN, Kim HJ, Koh JY. Role of zinc metallothionein-3 (ZnMt3) in epidermal growth factor (EGF)-induced c-Abl protein activation and actin polymerization in cultured astrocytes. J Biol Chem 2011; 286:40847-56. [PMID: 21900236 DOI: 10.1074/jbc.m111.245993] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Recent evidence indicates that zinc plays a major role in neurochemistry. Of the many zinc-binding proteins, metallothionein-3 (Mt3) is regarded as one of the major regulators of cellular zinc in the brain. However, biological functions of Mt3 are not yet well characterized. Recently, we found that lysosomal dysfunction in metallothionein-3 (Mt3)-null astrocytes involves down-regulation of c-Abl. In this study, we investigated the role of Mt3 in c-Abl activation and actin polymerization in cultured astrocytes following treatment with epidermal growth factor (EGF). Compared with wild-type (WT) astrocytes, Mt3-null cells exhibited a substantial reduction in the activation of c-Abl upon treatment with EGF. Consistent with previous studies, activation of c-Abl by EGF induced dissociation of c-Abl from F-actin. Mt3 added to astrocytic cell lysates bound F-actin, augmented F-actin polymerization, and promoted the dissociation of c-Abl from F-actin, suggesting a possible role for Mt3 in this process. Conversely, Mt3-deficient astrocytes showed significantly reduced dissociation of c-Abl from F-actin following EGF treatment. Experiments using various peptide fragments of Mt3 showed that a fragment containing the N-terminal TCPCP motif (peptide 1) is sufficient for this effect. Removal of zinc from Mt3 or pep1 with tetrakis(2-pyridylmethyl)ethylenediamine abrogated the effect of Mt3 on the association of c-Abl and F-actin, indicating that zinc binding is necessary for this action. These results suggest that ZnMt3 in cultured astrocytes may be a normal component of c-Abl activation in EGF receptor signaling. Hence, modulation of Mt3 levels or distribution may prove to be a useful strategy for controlling cytoskeletal mobilization following EGF stimulation in brain cells.
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Affiliation(s)
- Sook-Jeong Lee
- Neural Injury Research Lab, University of Ulsan College of Medicine, Seoul 138-736, Korea
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Blasig IE, Bellmann C, Cording J, Del Vecchio G, Zwanziger D, Huber O, Haseloff RF. Occludin protein family: oxidative stress and reducing conditions. Antioxid Redox Signal 2011; 15:1195-219. [PMID: 21235353 DOI: 10.1089/ars.2010.3542] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The occludin-like proteins belong to a family of tetraspan transmembrane proteins carrying a marvel domain. The intrinsic function of the occludin family is not yet clear. Occludin is a unique marker of any tight junction and is found in polarized endothelial and epithelial tissue barriers, at least in the adult vertebrate organism. Occludin is able to oligomerize and to form tight junction strands by homologous and heterologous interactions, but has no direct tightening function. Its oligomerization is affected by pro- and antioxidative agents or processes. Phosphorylation of occludin has been described at multiple sites and is proposed to play a regulatory role in tight junction assembly and maintenance and, hence, to influence tissue barrier characteristics. Redox-dependent signal transduction mechanisms are among the pathways modulating occludin phosphorylation and function. This review discusses the novel concept that occludin plays a key role in the redox regulation of tight junctions, which has a major impact in pathologies related to oxidative stress and corresponding pharmacologic interventions.
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Affiliation(s)
- Ingolf E Blasig
- Leibniz-Institut für Molekulare Pharmakologie, Berlin-Buch, Germany.
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Kim JH, Kim J, Park YH, Cheun KJ, Jang YH. Effects of postconditioning with N,N,N'N'-tetrakis-[2-pyridylmethyl]-ethylenediamine in isolated rat hearts. Korean J Anesthesiol 2010; 58:290-5. [PMID: 20498780 PMCID: PMC2872845 DOI: 10.4097/kjae.2010.58.3.290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 11/07/2009] [Accepted: 12/09/2009] [Indexed: 11/10/2022] Open
Abstract
Background It was reported that N,N,N'N'-tetrakis-[2-pyridylmethyl]-ethylenediamine (TPEN), a transition metal chelator, confers cardioprotection against myocardial ischemic injury. In this study, we investigated the effect of TPEN targeting reperfusion period in isolated rat hearts. Methods Langendorff perfused rat hearts were subjected to 30 min of regional ischemia and 2 h of reperfusion. Hearts were randomly assigned to either control (n = 9) or 10 µM of TPEN (n = 8) groups. TPEN was perfused for a period of 5 min before and 30 min after reperfusion. Results The ratio of infarct area/ischemic area (AN/AR) was significantly reduced in TPEN treated hearts (6.9 ± 1.7%, P < 0.001) compared to control hearts (29.5 ± 3.2%). Recovery of left ventricular developed pressure (LVDP), rate-pressure product (RPP), +dP/dtmax, and -dP/dtmin in the control group after reperfusion were 53.8 ± 6.2%, 51.0 ± 6.3%, 51.9 ± 5.7%, and 51.4 ± 5.7%, respectively, of the baseline levels. In the TPEN group, LVDP, RPP, +dP/dtmax, and -dP/dtmin returned to 58.5 ± 4.6%, 54.8 ± 6.4%, 61.7 ± 4.9%, and 53.4 ± 3.9%, respectively, of the baseline levels. There were no significant differences in the cardiodynamic variables between the two groups (P > 0.05). Conclusions Pharmacological postconditioning with TPEN reduces myocardial infarction however, TPEN does not modify post-ischemic systolic dysfunction in isolated rat hearts.
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Affiliation(s)
- Joon Hong Kim
- Institute of Cardiovascular Research, Pusan National University Yangsan Hospital, Yangsan, Korea
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Protecting against antimicrobial effectors in the phagosome allows SodCII to contribute to virulence in Salmonella enterica serovar Typhimurium. J Bacteriol 2010; 192:2140-9. [PMID: 20154132 DOI: 10.1128/jb.00016-10] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Typhimurium replicates in macrophages, where it is subjected to antimicrobial substances, including superoxide, antimicrobial peptides, and proteases. The bacterium produces two periplasmic superoxide dismutases, SodCI and SodCII. Although both are expressed during infection, only SodCI contributes to virulence in the mouse by combating phagocytic superoxide. The differential contribution to virulence is at least partially due to inherent differences in the SodCI and SodCII proteins that are independent of enzymatic activity. SodCII is protease sensitive, and like other periplasmic proteins, it is released by osmotic shock. In contrast, SodCI is protease resistant and is retained within the periplasm after osmotic shock, a phenomenon that we term "tethering." We hypothesize that in the macrophage, antimicrobial peptides transiently disrupt the outer membrane. SodCII is released and/or phagocytic proteases gain access to the periplasm, and SodCII is degraded. SodCI is tethered within the periplasm and is protease resistant, thereby remaining to combat superoxide. Here we test aspects of this model. SodCII was released by the antimicrobial peptide polymyxin B or a mouse macrophage antimicrobial peptide (CRAMP), while SodCI remained tethered within the periplasm. A Salmonella pmrA constitutive mutant no longer released SodCII in vitro. Moreover, in the constitutive pmrA background, SodCII could contribute to survival of Salmonella during infection. SodCII also provided a virulence benefit in mice genetically defective in production of CRAMP. Thus, consistent with our model, protecting the outer membrane against antimicrobial peptides allows SodCII to contribute to virulence in vivo. These data also suggest direct in vivo cooperative interactions between macrophage antimicrobial effectors.
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Altered sarcoplasmic reticulum calcium transport in the presence of the heavy metal chelator TPEN. Cell Calcium 2009; 46:347-55. [PMID: 19900703 DOI: 10.1016/j.ceca.2009.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 10/01/2009] [Accepted: 10/05/2009] [Indexed: 11/21/2022]
Abstract
TPEN (N,N,N',N'-tetrakis(2-pyridylmethyl)-ethylenediamine) is a membrane-permeable heavy-metal ion chelator with a dissociation constant for Ca2+ comparable to the Ca2+ concentration ([Ca2+]) within the intracellular Ca2+ stores. It has been used as modulator of intracellular heavy metals and of free intraluminal [Ca2+], without influencing the cytosolic [Ca2+] that falls in the nanomolar range. In our previous studies, we gave evidence that TPEN modifies the Ca2+ homeostasis of striated muscle independent of this buffering ability. Here we describe the direct interaction of TPEN with the ryanodine receptor (RyR) Ca2+ release channel and the sarcoplasmic reticulum (SR) Ca2+ pump (SERCA). In lipid bilayers, at negative potentials and low [Ca2+], TPEN increased the open probability of RyR, while at positive potentials it inhibited channel activity. On permeabilized skeletal muscle fibers of the frog, but not of the rat, 50 microM TPEN increased the number of spontaneous Ca2+ sparks and induced propagating events with a velocity of 273 +/- 7 microm/s. Determining the hydrolytic activity of the SR revealed that TPEN inhibits the SERCA pump, with an IC(50) = 692 +/- 62 microM and a Hill coefficient of 0.88 +/- 0.10. These findings provide experimental evidence that TPEN directly modifies both the release of Ca2+ from and its reuptake into the SR.
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Lau CK, Delmar VA, Chan RC, Phung Q, Bernis C, Fichtman B, Rasala BA, Forbes DJ. Transportin regulates major mitotic assembly events: from spindle to nuclear pore assembly. Mol Biol Cell 2009; 20:4043-58. [PMID: 19641022 DOI: 10.1091/mbc.e09-02-0152] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Mitosis in higher eukaryotes is marked by the sequential assembly of two massive structures: the mitotic spindle and the nucleus. Nuclear assembly itself requires the precise formation of both nuclear membranes and nuclear pore complexes. Previously, importin alpha/beta and RanGTP were shown to act as dueling regulators to ensure that these assembly processes occur only in the vicinity of the mitotic chromosomes. We now find that the distantly related karyopherin, transportin, negatively regulates nuclear envelope fusion and nuclear pore assembly in Xenopus egg extracts. We show that transportin-and importin beta-initiate their regulation as early as the first known step of nuclear pore assembly: recruitment of the critical pore-targeting nucleoporin ELYS/MEL-28 to chromatin. Indeed, each karyopherin can interact directly with ELYS. We further define the nucleoporin subunit targets for transportin and importin beta and find them to be largely the same: ELYS, the Nup107/160 complex, Nup53, and the FG nucleoporins. Equally importantly, we find that transportin negatively regulates mitotic spindle assembly. These negative regulatory events are counteracted by RanGTP. We conclude that the interplay of the two negative regulators, transportin and importin beta, along with the positive regulator RanGTP, allows precise choreography of multiple cell cycle assembly events.
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Affiliation(s)
- Corine K Lau
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093-0347, USA
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Endogenous zinc mediates apoptotic programmed cell death in the developing brain. Neurotox Res 2009; 17:156-66. [PMID: 19609831 DOI: 10.1007/s12640-009-9085-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 05/29/2009] [Accepted: 06/12/2009] [Indexed: 10/20/2022]
Abstract
Endogenous zinc can mediate the apoptotic programmed cell death (PCD) in the developing brain. Intensive accumulation of labile zinc occurs in almost all neurons undergoing PCD in the developing rat brain. Based on the greater frequency of neurons with intensive zinc accumulation compared to apoptotic neurons, it is inferred that cytosolic zinc accumulation precedes apoptotic PCD. To determine the role of intracellular labile zinc in developmental apoptosis, we subcutaneously injected the membrane-permeant zinc chelator, N,N,N',N-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) into postnatal rats for 7 days after birth. TPEN chelated intraneuronal zinc without modulating the expression of the zinc-regulating proteins, ZnT-1, ZnT-3, and synaptophysin. The frequency of apoptotic neurons significantly decreased in TPEN-treated rat brains compared with that in normal postnatal rats. Activating cleavages of caspase-9 and -3, and mitochondrial pro-apoptotic Bax expression were reduced, whereas expression of anti-apoptotic Bcl-2 was increased. Thus, intracerebral zinc chelation may arrest PCD in the developing brain by interfering with the caspase-dependent apoptotic pathway. The present study demonstrates that intracellular zinc acts as a key mediator of developmental apoptosis and therefore provides the first in vivo evidence that endogenous labile zinc causes neuronal apoptosis.
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Dechat T, Pfleghaar K, Sengupta K, Shimi T, Shumaker DK, Solimando L, Goldman RD. Nuclear lamins: major factors in the structural organization and function of the nucleus and chromatin. Genes Dev 2008; 22:832-53. [PMID: 18381888 PMCID: PMC2732390 DOI: 10.1101/gad.1652708] [Citation(s) in RCA: 719] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Over the past few years it has become evident that the intermediate filament proteins, the types A and B nuclear lamins, not only provide a structural framework for the nucleus, but are also essential for many aspects of normal nuclear function. Insights into lamin-related functions have been derived from studies of the remarkably large number of disease-causing mutations in the human lamin A gene. This review provides an up-to-date overview of the functions of nuclear lamins, emphasizing their roles in epigenetics, chromatin organization, DNA replication, transcription, and DNA repair. In addition, we discuss recent evidence supporting the importance of lamins in viral infections.
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Affiliation(s)
- Thomas Dechat
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Katrin Pfleghaar
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Kaushik Sengupta
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Takeshi Shimi
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Dale K. Shumaker
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Liliana Solimando
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | - Robert D. Goldman
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
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Sztretye M, Deli T, Szentesi P, Szigeti G, Csernoch L. Effect of TPEN on the calcium release of cultured C2C12 mouse myotubes. J Muscle Res Cell Motil 2008; 28:421-8. [DOI: 10.1007/s10974-008-9135-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Accepted: 03/06/2008] [Indexed: 11/27/2022]
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Delmar VA, Chan RC, Forbes DJ. Xenopus importin beta validates human importin beta as a cell cycle negative regulator. BMC Cell Biol 2008; 9:14. [PMID: 18366719 PMCID: PMC2324082 DOI: 10.1186/1471-2121-9-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 03/22/2008] [Indexed: 11/12/2022] Open
Abstract
Background Human importin beta has been used in all Xenopus laevis in vitro nuclear assembly and spindle assembly studies. This disconnect between species raised the question for us as to whether importin beta was an authentic negative regulator of cell cycle events, or a dominant negative regulator due to a difference between the human and Xenopus importin beta sequences. No Xenopus importin beta gene was yet identified at the time of those studies. Thus, we first cloned, identified, and tested the Xenopus importin beta gene to address this important mechanistic difference. If human importin beta is an authentic negative regulator then we would expect human and Xenopus importin beta to have identical negative regulatory effects on nuclear membrane fusion and pore assembly. If human importin beta acts instead as a dominant negative mutant inhibitor, we should then see no inhibitory effect when we added the Xenopus homologue. Results We found that Xenopus importin beta acts identically to its human counterpart. It negatively regulates both nuclear membrane fusion and pore assembly. Human importin beta inhibition was previously found to be reversible by Ran for mitotic spindle assembly and nuclear membrane fusion, but not nuclear pore assembly. During the present study, we observed that this differing reversibility varied depending on the presence or absence of a tag on importin beta. Indeed, when untagged importin beta, either human or Xenopus, was used, inhibition of nuclear pore assembly proved to be Ran-reversible. Conclusion We conclude that importin beta, human or Xenopus, is an authentic negative regulator of nuclear assembly and, presumably, spindle assembly. A difference in the Ran sensitivity between tagged and untagged importin beta in pore assembly gives us mechanistic insight into nuclear pore formation.
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Affiliation(s)
- Valerie A Delmar
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, University of California - San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0347, USA.
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Cho YE, Lomeda RAR, Ryu SH, Lee JH, Beattie JH, Kwun IS. Cellular Zn depletion by metal ion chelators (TPEN, DTPA and chelex resin) and its application to osteoblastic MC3T3-E1 cells. Nutr Res Pract 2007; 1:29-35. [PMID: 20535382 PMCID: PMC2882573 DOI: 10.4162/nrp.2007.1.1.29] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 03/03/2007] [Accepted: 03/14/2007] [Indexed: 11/04/2022] Open
Abstract
Trace mineral studies involving metal ion chelators have been conducted in investigating the response of gene and protein expressions of certain cell lines but a few had really focused on how these metal ion chelators could affect the availability of important trace minerals such as Zn, Mn, Fe and Cu. The aim of the present study was to investigate the availability of Zn for the treatment of MC3T3-E1 osteoblast-like cells and the availability of some trace minerals in the cell culture media components after using chelexing resin in the FBS and the addition of N,N,N',N'-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN, membrane-permeable chelator) and diethylenetriaminepentaacetic acid (DTPA, membrane-impermeable chelator) in the treatment medium. Components for the preparation of cell culture medium and Zn-treated medium have been tested for Zn, Mn, Fe and Cu contents by atomic absorption spectrophotometer or inductively coupled plasma spectrophotometer. Also, the expression of bone-related genes (ALP, Runx2, PTH-R, ProCOL I, OPN and OC) was measured on the cellular Zn depletion such as chelexing or TPEN treatment. Results have shown that using the chelexing resin in FBS would significantly decrease the available Zn (p<0.05) (39.4 +/- 1.5 microM vs 0.61 +/- 10.15 microM) and Mn (p<0.05) (0.74 +/- 0.01 microM vs 0.12 +/- 0.04 microM). However, levels of Fe and Cu in FBS were not changed by chelexing FBS. The use of TPEN and DTPA as Zn-chelators did not show significant difference on the final concentration of Zn in the treatment medium (0, 3, 6, 9, 12 microM) except for in the addition of higher 15 microM ZnCl(2) which showed a significant increase of Zn level in DTPA-chelated treatment medium. Results have shown that both chelators gave the same pattern for the expression of the five bone-related genes between Zn- and Zn+, and TPEN-treated experiments, compared to chelex-treated experiment, showed lower bone-related gene expression, which may imply that TPEN would be a stronger chelator than chelex resin. This study showed that TPEN would be a stronger chelator compared to DTPA or chelex resin and TPEN and chelex resin exerted cellular zinc depletion to be enough for cell study for Zn depletion.
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Affiliation(s)
- Young-Eun Cho
- Department of Food and Nutrition, Andong National University, Gyeongbuk 760-749, Korea
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Jung C, Zima AV, Szentesi P, Jona I, Blatter LA, Niggli E. Ca2+ release from the sarcoplasmic reticulum activated by the low affinity Ca2+ chelator TPEN in ventricular myocytes. Cell Calcium 2007; 41:187-94. [PMID: 16920191 DOI: 10.1016/j.ceca.2006.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Accepted: 06/29/2006] [Indexed: 11/27/2022]
Abstract
The Ca2+ content of the sarcoplasmic reticulum (SR) of cardiac myocytes is thought to play a role in the regulation and termination of SR Ca2+ release through the ryanodine receptors (RyRs). Experimentally altering the amount of Ca2+ within the SR with the membrane-permeant low affinity Ca2+ chelator TPEN could improve our understanding of the mechanism(s) by which SR Ca2+ content and SR Ca2+ depletion can influence Ca2+ release sensitivity and termination. We applied laser-scanning confocal microscopy to examine SR Ca2+ release in freshly isolated ventricular myocytes loaded with fluo-3, while simultaneously recording membrane currents using the whole-cell patch-clamp technique. Following application of TPEN, local spontaneous Ca2+ releases increased in frequency and developed into cell-wide Ca2+ waves. SR Ca2+ load after TPEN application was found to be reduced to about 60% of control. Isolated cardiac RyRs reconstituted into lipid bilayers exhibited a two-fold increase of their open probability. At the low concentration used (20-40microTPEN did not significantly inhibit the SR-Ca2+-ATPase in SR vesicles. These results indicate that TPEN, traditionally used as a low affinity Ca2+ chelator in intracellular Ca2+ stores, may also act directly on the RyRs inducing an increase in their open probability. This in turn results in an increased Ca2+ leak from the SR leading to its Ca2+ depletion. Lowering of SR Ca2+ content may be a mechanism underlying the recently reported cardioprotective and antiarrhythmic features of TPEN.
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Affiliation(s)
- C Jung
- Department of Physiology, University of Bern, Buehlplatz 5, 3012 Bern, Switzerland
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40
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Paus R, Schröder JM. Viewpoint 1. Exp Dermatol 2006. [DOI: 10.1111/j.1600-0625.2006.00506_2.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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41
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Paus R, Schröder JM, Reich K, Kabashima K, Liu FT, Romani N, Metz M, Kerstan A, Lee PHA, Loser K, Schön MP, Maurer M, Stoitzner P, Beissert S, Tokura Y, Gallo RL, Reich K. Who is really in control of skin immunity underphysiologicalcircumstances - lymphocytes, dendritic cells or keratinocytes? Exp Dermatol 2006. [DOI: 10.1111/j.1600-0625.2006.00506.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Abstract
DNA microarrays were used to probe the transcriptional response of Escherichia coli to N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN). Fifty-five transcripts were significantly up-regulated, including all of the genes that are regulated by Zur and many that are regulated by Fur. In the same TPEN-treated cells, 46 transcripts were significantly down-regulated.
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Affiliation(s)
- Tara K Sigdel
- Department of Chemistry and Biochemistry, 160 Hughes Hall, Miami University, Oxford, OH 45056, USA
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43
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Choi JS, Kim KA, Yoon YJ, Fujikado T, Joo CK. Inhibition of cyclooxygenase-2 expression by zinc-chelator in retinal ischemia. Vision Res 2006; 46:2721-7. [PMID: 16584753 DOI: 10.1016/j.visres.2006.02.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Revised: 01/31/2006] [Accepted: 02/01/2006] [Indexed: 01/26/2023]
Abstract
The zinc ion (Zn2+) is abundant in neurons. However, excessive Zn2+ can induce neuronal cell death. This study examined the role of Zn2+ in transient retinal ischemia in adult male rats. The rats were sacrificed 4-24 h after retinal ischemia by high intra-ocular pressure, and the retinas were prepared for microscopic examination of retinal cell degeneration, and fluorescence microscopy using zinquin ethyl ester as the zinc ion-specific probe. Moreover, COX-2 expression was observed by Western blotting. In control retinas, there was a low Zn2+ concentration in the inner plexiform layer (IPL), a high Zn2+ concentration in the outer plexiform layer (OPL), and no detectable Zn2+ in either the ganglion cell layer (GCL) or the inner nuclear layer (INL). In contrast, in the retinas exposed to ischemia without the administration of the zinc ion chelators (Ca2+-EDTA and TPEN), Zn2+ deposits were found in the IPL and INL beginning 4 h after ischemia and degeneration of neurons was found in the GCL and INL. Less Zn2+ accumulation in the IPL and INL and less neuronal degeneration in the GCL and INL were found in the retinas treated with Ca2+-EDTA or TPEN before ischemia. Furthermore, the COX-2 protein levels increased 4-8 h after retinal ischemia, and chelation of zinc ion inhibited this effect. These results suggest that the accumulation of Zn2+ following an ischemic insult can cause retinal degeneration and induce abnormal COX-2 expression.
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Affiliation(s)
- Jun-Sub Choi
- Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seocho-ku, Seoul 137-701, Republic of Korea
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St Croix CM, Leelavaninchkul K, Watkins SC, Kagan VE, Pitt BR. Nitric oxide and zinc homeostasis in acute lung injury. Ann Am Thorac Soc 2006; 2:236-42. [PMID: 16222044 PMCID: PMC2713321 DOI: 10.1513/pats.200501-007ac] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Among putative small molecules that affect sensitivity to acute lung injury, zinc and nitric oxide are potentially unique by virtue of their interdependence and dual capacities to be cytoprotective or injurious. Nitric oxide and zinc appear to be linked via an intracellular signaling pathway involving S-nitrosation of metallothoinein--itself a small protein known to be an important inducible gene product that may modify lung injury. In the present article, we summarize recent efforts using genetic and fluorescence optical imaging techniques to: (1) demonstrate that S-nitrosation of metallothionein affects intracellular zinc homeostasis in intact pulmonary endothelial cells; and (2) reveal a protective role for this pathway in hyperoxic and LPS-induced injury.
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Affiliation(s)
- Claudette M St Croix
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School Public Health, Pittsburgh, PA 15260, USA.
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45
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Gläser R, Harder J, Lange H, Bartels J, Christophers E, Schröder JM. Antimicrobial psoriasin (S100A7) protects human skin from Escherichia coli infection. Nat Immunol 2004; 6:57-64. [PMID: 15568027 DOI: 10.1038/ni1142] [Citation(s) in RCA: 489] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Accepted: 11/01/2004] [Indexed: 11/09/2022]
Abstract
Human healthy skin is continuously exposed to bacteria, but is particularly resistant to the common gut bacterium Escherichia coli. We show here that keratinocytes secrete, as the main E. coli-killing compound, the S100 protein psoriasin in vitro and in vivo in a site-dependent way. In vivo treatment of human skin with antibodies to psoriasin inhibited its E. coli-killing properties. Psoriasin was induced in keratinocytes in vitro and in vivo by E. coli, indicating that its focal expression in skin may derive from local microbial induction. Zn(2+)-saturated psoriasin showed diminished antimicrobial activity, suggesting that Zn(2+) sequestration could be a possible antimicrobial mechanism. Thus, psoriasin may be key to the resistance of skin against E. coli.
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Affiliation(s)
- Regine Gläser
- Clinical Research Unit of the Department of Dermatology, University Hospital Schleswig-Holstein, Campus Kiel, Germany
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Costanzo V, Paull T, Gottesman M, Gautier J. Mre11 assembles linear DNA fragments into DNA damage signaling complexes. PLoS Biol 2004; 2:E110. [PMID: 15138496 PMCID: PMC406388 DOI: 10.1371/journal.pbio.0020110] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2003] [Accepted: 02/10/2004] [Indexed: 11/25/2022] Open
Abstract
Mre11/Rad50/Nbs1 complex (MRN) is essential to suppress the generation of double-strand breaks (DSBs) during DNA replication. MRN also plays a role in the response to DSBs created by DNA damage. Hypomorphic mutations in Mre11 (which causes an ataxia-telangiectasia-like disease [ATLD]) and mutations in the ataxia-telangiectasia-mutated (ATM) gene lead to defects in handling damaged DNA and to similar clinical and cellular phenotypes. Using Xenopus egg extracts, we have designed a simple assay to define the biochemistry of Mre11. MRN is required for efficient activation of the DNA damage response induced by DSBs. We isolated a high molecular weight DNA damage signaling complex that includes MRN, damaged DNA molecules, and activated ATM. Complex formation is partially dependent upon Zn(2+) and requires an intact Mre11 C-terminal domain that is deleted in some ATLD patients. The ATLD truncation can still perform the role of Mre11 during replication. Our work demonstrates the role of Mre11 in assembling DNA damage signaling centers that are reminiscent of irradiation-induced foci. It also provides a molecular explanation for the similarities between ataxia-telangiectasia (A-T) and ATLD.
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Affiliation(s)
- Vincenzo Costanzo
- Department of Genetics and Development, Columbia University, New York, New York, USA
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47
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Quinta-Ferreira ME, Matias CM. Hippocampal mossy fiber calcium transients are maintained during long-term potentiation and are inhibited by endogenous zinc. Brain Res 2004; 1004:52-60. [PMID: 15033419 DOI: 10.1016/j.brainres.2004.01.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2004] [Indexed: 10/26/2022]
Abstract
The hippocampal mossy fiber long-term potentiation (LTP) is an N-methyl-d-aspartate (NMDA) receptor-independent form of long-lasting synaptic plasticity characteristic of the zinc-enriched mossy fiber synapses. Its expression is generally considered to have a presynaptic locus and to be mediated by a persistent increase of evoked transmitter release. Because the release process is calcium-dependent, the observed increase in synaptic efficacy could be due to a persistent modification of presynaptic calcium mechanisms, triggered by the large calcium influx associated with long-term potentiation induction. Alternatively, it might be caused by an enhancement in the sensitivity to calcium of some components of the synaptic vesicle release system, following the large intraterminal calcium accumulation. We investigated the first hypothesis by measuring presynaptic Fura-2 calcium signals associated with electrically induced mossy fiber long-term potentiation. We have observed that like residual calcium, single presynaptic calcium changes are not enhanced during the maintenance phase of mossy fiber long-term potentiation. This result supports the idea that this form of long-term potentiation may be mediated by persistent changes of some process occurring after calcium entry. It has been established that voltage-dependent calcium channels are inhibited by zinc and that endogenous zinc is released in a calcium-dependent way following intense mossy fiber activation. Because there is evidence that at these synapses zinc is also released following single electrical stimulation, we investigated the effect of endogenous zinc on single presynaptic calcium signals and on field potentials associated with mossy fiber LTP. We have observed that this form of LTP could be induced in the presence of the permeant heavy metal chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) and that application of this chelator, during LTP, caused an enhancement of the presynaptic calcium signals without affecting synaptic transmission. This enhancement is consistent with the idea that mossy fiber zinc, released following individual stimuli, inhibits presynaptic calcium mechanisms.
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Affiliation(s)
- M E Quinta-Ferreira
- Department of Physics and Center for Neurosciences of Coimbra, University of Coimbra, 3004-516 Coimbra, Portugal.
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48
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Badciong JC, Haas AL. MdmX is a RING finger ubiquitin ligase capable of synergistically enhancing Mdm2 ubiquitination. J Biol Chem 2002; 277:49668-75. [PMID: 12393902 DOI: 10.1074/jbc.m208593200] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
It has been well documented that Mdm2 and its homologue MdmX not only are critical negative regulators of the tumor suppressor p53 but that both Mdm2 and MdmX interact to affect the function of the other. The mechanisms through which these effects are manifested, however, remain unclear. Although Mdm2 has been established as a RING finger ubiquitin ligase, MdmX has not been shown to possess this activity despite the extensive sequence homology between their respective RING finger domains. Here we demonstrate that MdmX acts as a ubiquitin ligase in vitro, being capable of autoubiquitination, as well as mediating the ubiquitination of p53. The addition of Mdm2 to in vitro ubiquitination assays containing MdmX results in a synergistic increase of ubiquitin conjugation. Analysis of the resulting ubiquitin conjugates reveals that this observed synergy reflects an increase in Mdm2 ubiquitination. This study also suggests that ubiquitination of Mdm2 and MdmX may not serve as a signal for degradation, as we show that each are capable of synthesizing non-lysine 48 polyubiquitin chains and, in fact, utilize multiple lysine linkages. Taken together, these findings suggest a more active role for MdmX in the Mdm2-MdmX-p53 regulatory network than has been proposed previously.
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Affiliation(s)
- James C Badciong
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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49
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Drummond SP, Wilson KL. Interference with the cytoplasmic tail of gp210 disrupts "close apposition" of nuclear membranes and blocks nuclear pore dilation. J Cell Biol 2002; 158:53-62. [PMID: 12093788 PMCID: PMC2173024 DOI: 10.1083/jcb.200108145] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2001] [Revised: 05/16/2002] [Accepted: 05/20/2002] [Indexed: 12/12/2022] Open
Abstract
We tested the hypothesis that gp210, an integral membrane protein of nuclear pore complexes (NPCs), mediates nuclear pore formation. Gp210 has a large lumenal domain and small COOH-terminal tail exposed to the cytoplasm. We studied the exposed tail. We added recombinant tail polypeptides to Xenopus nuclear assembly extracts, or inhibited endogenous gp210 tails using anti-tail antibodies. Both strategies had no effect on the formation of fused flattened nuclear membranes, but blocked NPC assembly and nuclear growth. Inhibited nuclei accumulated gp210 and some nucleoporin p62, but failed to incorporate nup214/CAN, nup153, or nup98 and were defective for nuclear import of lamin B3. Scanning and transmission EM revealed a lack of "closely apposed" inner and outer membranes, and the accumulation of novel arrested structures including "mini-pores." We conclude that gp210 has early roles in nuclear pore formation, and that pore dilation is mediated by gp210 and its tail-binding partner(s). We propose that membrane fusion and pore dilation are coupled, acting as a mechanism to control nuclear pore size.
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Affiliation(s)
- Sheona P Drummond
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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50
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Aizenman E, Stout AK, Hartnett KA, Dineley KE, McLaughlin B, Reynolds IJ. Induction of neuronal apoptosis by thiol oxidation: putative role of intracellular zinc release. J Neurochem 2000; 75:1878-88. [PMID: 11032877 DOI: 10.1046/j.1471-4159.2000.0751878.x] [Citation(s) in RCA: 314] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The membrane-permeant oxidizing agent 2,2'-dithiodipyridine (DTDP) can induce Zn(2+) release from metalloproteins in cell-free systems. Here, we report that brief exposure to DTDP triggers apoptotic cell death in cultured neurons, detected by the presence of both DNA laddering and asymmetric chromatin formation. Neuronal death was blocked by increased extracellular potassium levels, by tetraethylammonium, and by the broad-spectrum cysteine protease inhibitor butoxy-carbonyl-aspartate-fluoromethylketone. N,N,N', N'-Tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) and other cell-permeant metal chelators also effectively blocked DTDP-induced toxicity in neurons. Cell death, however, was not abolished by the NMDA receptor blocker MK-801, by the intracellular calcium release antagonist dantrolene, or by high concentrations of ryanodine. DTDP generated increases in fluorescence signals in cultured neurons loaded with the zinc-selective dye Newport Green. The fluorescence signals following DTDP treatment also increased in fura-2- and magfura-2-loaded neurons. These responses were completely reversed by TPEN, consistent with a DTDP-mediated increase in intracellular free Zn(2+) concentrations. Our studies suggest that under conditions of oxidative stress, Zn(2+) released from intracellular stores may contribute to the initiation of neuronal apoptosis.
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Affiliation(s)
- E Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
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