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Zlatar L, Mahajan A, Muñoz-Becerra M, Weidner D, Bila G, Bilyy R, Titze J, Hoffmann MH, Schett G, Herrmann M, Steffen U, Muñoz LE, Knopf J. Suppression of neutrophils by sodium exacerbates oxidative stress and arthritis. Front Immunol 2023; 14:1174537. [PMID: 37600805 PMCID: PMC10433750 DOI: 10.3389/fimmu.2023.1174537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 07/14/2023] [Indexed: 08/22/2023] Open
Abstract
Introduction Typical Western diet, rich in salt, contributes to autoimmune disease development. However, conflicting reports exist about the effect of salt on neutrophil effector functions, also in the context of arthritis. Methods We investigated the effect of sodium chloride (NaCl) on neutrophil viability and functions in vitro, and in vivo employing the murine K/BxN-serum transfer arthritis (STA) model. Results and discussion The effects of NaCl and external reactive oxygen species (H2O2) were further examined on osteoclasts in vitro. Hypertonic sodium-rich media caused primary/secondary cell necrosis, altered the nuclear morphology, inhibited phagocytosis, degranulation, myeloperoxidase (MPO) peroxidation activity and neutrophil extracellular trap (NET) formation, while increasing total ROS production, mitochondrial ROS production, and neutrophil elastase (NE) activity. High salt diet (HSD) aggravated arthritis by increasing inflammation, bone erosion, and osteoclast differentiation, accompanied by increased NE expression and activity. Osteoclast differentiation was decreased with 25 mM NaCl or 100 nM H2O2 addition to isotonic media. In contrast to NaCl, external H2O2 had pro-resorptive effects in vitro. We postulate that in arthritis under HSD, increased bone erosion can be attributed to an enhanced oxidative milieu maintained by infiltrating neutrophils, rather than a direct effect of NaCl.
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Affiliation(s)
- Leticija Zlatar
- Department of Internal Medicine 3 – Rheumatology and Immunology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander-University Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
| | - Aparna Mahajan
- Department of Internal Medicine 3 – Rheumatology and Immunology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander-University Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
| | - Marco Muñoz-Becerra
- Department of Internal Medicine 3 – Rheumatology and Immunology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander-University Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
| | - Daniela Weidner
- Department of Internal Medicine 3 – Rheumatology and Immunology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany
| | - Galyna Bila
- Department of Histology, Cytology, Embryology, Danylo Halytsky Lviv National Medical University, Lviv, Ukraine
| | - Rostyslav Bilyy
- Department of Histology, Cytology, Embryology, Danylo Halytsky Lviv National Medical University, Lviv, Ukraine
| | - Jens Titze
- Division of Nephrology and Hypertension, Universitätsklinikum Erlangen, Erlangen, Germany
- Programme in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Markus H. Hoffmann
- Department of Dermatology, Allergology, and Venereology, University of Lübeck, Lübeck, Germany
| | - Georg Schett
- Department of Internal Medicine 3 – Rheumatology and Immunology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander-University Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
| | - Martin Herrmann
- Department of Internal Medicine 3 – Rheumatology and Immunology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander-University Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
| | - Ulrike Steffen
- Department of Internal Medicine 3 – Rheumatology and Immunology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander-University Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
| | - Luis E. Muñoz
- Department of Internal Medicine 3 – Rheumatology and Immunology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander-University Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
| | - Jasmin Knopf
- Department of Internal Medicine 3 – Rheumatology and Immunology, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander-University Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
- Department of Pediatric Surgery, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
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Li D, Shen L, Zhang D, Wang X, Wang Q, Qin W, Gao Y, Li X. Ammonia-induced oxidative stress triggered proinflammatory response and apoptosis in pig lungs. J Environ Sci (China) 2023; 126:683-696. [PMID: 36503793 DOI: 10.1016/j.jes.2022.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 05/06/2022] [Accepted: 05/07/2022] [Indexed: 06/17/2023]
Abstract
Ammonia, a common toxic gas, is not only one of the main causes of haze, but also can enter respiratory tract and directly affect the health of humans and animals. Pig was used as an animal model for exploring the molecular mechanism and dose effect of ammonia toxicity to lung. In this study, the apoptosis of type II alveolar epithelial cells was observed in high ammonia exposure group using transmission electron microscopy. Gene and protein expression analysis using transcriptome sequencing and western blot showed that low ammonia exposure induced T-cell-involved proinflammatory response, but high ammonia exposure repressed the expression of DNA repair-related genes and affected ion transport. Moreover, high ammonia exposure significantly increased 8-hydroxy-2-deoxyguanosine (8-OHdG) level, meaning DNA oxidative damage occurred. In addition, both low and high ammonia exposure caused oxidative stress in pig lungs. Integrated analysis of transcriptome and metabolome revealed that the up-regulation of LDHB and ND2 took part in high ammonia exposure-affected pyruvate metabolism and oxidative phosphorylation progress, respectively. Inclusion, oxidative stress mediated ammonia-induced proinflammatory response and apoptosis of porcine lungs. These findings may provide new insights for understanding the ammonia toxicity to workers in livestock farms and chemical fertilizer plants.
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Affiliation(s)
- Daojie Li
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, China
| | - Long Shen
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, China
| | - Di Zhang
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiaotong Wang
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiankun Wang
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, China
| | - Wenhao Qin
- College of Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Yun Gao
- College of Engineering, The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiaoping Li
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, China.
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3
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Du C, Xu H, Cao C, Cao J, Zhang Y, Zhang C, Qiao R, Ming W, Li Y, Ren H, Cui X, Luan Z, Guan Y, Zhang X. Neutral amino acid transporter SLC38A2 protects renal medulla from hyperosmolarity-induced ferroptosis. eLife 2023; 12:80647. [PMID: 36722887 PMCID: PMC9949798 DOI: 10.7554/elife.80647] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 01/31/2023] [Indexed: 02/02/2023] Open
Abstract
Hyperosmolarity of the renal medulla is essential for urine concentration and water homeostasis. However, how renal medullary collecting duct (MCD) cells survive and function under harsh hyperosmotic stress remains unclear. Using RNA-Seq, we identified SLC38A2 as a novel osmoresponsive neutral amino acid transporter in MCD cells. Hyperosmotic stress-induced cell death in MCD cells occurred mainly via ferroptosis, and it was significantly attenuated by SLC38A2 overexpression but worsened by Slc38a2-gene deletion or silencing. Mechanistic studies revealed that the osmoprotective effect of SLC38A2 is dependent on the activation of mTORC1. Moreover, an in vivo study demonstrated that Slc38a2-knockout mice exhibited significantly increased medullary ferroptosis following water restriction. Collectively, these findings reveal that Slc38a2 is an important osmoresponsive gene in the renal medulla and provide novel insights into the critical role of SLC38A2 in protecting MCD cells from hyperosmolarity-induced ferroptosis via the mTORC1 signalling pathway.
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Affiliation(s)
- Chunxiu Du
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Dalian Medical UniversityDalianChina
- Dalian Key Laboratory for Nuclear Receptors in Major Metabolic DiseasesDalianChina
- Health Science Center, East China Normal UniversityShanghaiChina
| | - Hu Xu
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Cong Cao
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Jiahui Cao
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Yufei Zhang
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Cong Zhang
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Rongfang Qiao
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Wenhua Ming
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Yaqing Li
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Huiwen Ren
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Xiaohui Cui
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Zhilin Luan
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Youfei Guan
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Dalian Medical UniversityDalianChina
- Dalian Key Laboratory for Nuclear Receptors in Major Metabolic DiseasesDalianChina
| | - Xiaoyan Zhang
- Health Science Center, East China Normal UniversityShanghaiChina
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4
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Dang PA, Palomino-Durand C, Elsafi Mabrouk M, Marquaille P, Odier C, Norvez S, Pauthe E, Corté L. Rational formulation design of injectable thermosensitive chitosan-based hydrogels for cell encapsulation and delivery. Carbohydr Polym 2022; 277:118836. [PMID: 34893253 DOI: 10.1016/j.carbpol.2021.118836] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 09/12/2021] [Accepted: 10/27/2021] [Indexed: 11/26/2022]
Abstract
This work reports a rational design of injectable thermosensitive chitosan systems for cell encapsulation and delivery. Using mixtures of two phosphate salts, beta-glycerophosphate and ammonium hydrogen phosphate, we demonstrate that the pH and the osmolarity can be adjusted separately by varying the molar ratios between the salts and the d-glucosamine monomers. We found the existence of a critical temperature above which gelation time decays following a power-law. This gelation kinetics can be finely tuned through the pH and salt-glucosamine ratios. Formulations having physiological pH and osmolarity were produced for chitosan concentrations ranging from 0.4 to 0.9 wt%. They remain liquid for more than 2 h at 20 °C and form a macroporous gel within 2 min at 37 °C. In vitro encapsulation of pre-osteoblastic cells and gingival fibroblasts showed homogeneous cell distribution and good cell viability up to 24 h. Such an approach provides a valuable platform to design thermosensitive cell-laden systems.
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Affiliation(s)
- Phuong Anh Dang
- Molecular, Macromolecular Chemistry and Materials, C3M, ESPCI Paris, CNRS, PSL University, 10 rue Vauquelin, 75005 Paris, France; Équipe de Recherche sur les Relations Matrice Extracellulaire-Cellule, ERRMECe, CY Cergy Paris Université, Maison Internationale de la Recherche, 1 rue Descartes, 95000 Neuville-sur-Oise, France
| | - Carla Palomino-Durand
- Équipe de Recherche sur les Relations Matrice Extracellulaire-Cellule, ERRMECe, CY Cergy Paris Université, Maison Internationale de la Recherche, 1 rue Descartes, 95000 Neuville-sur-Oise, France
| | - Mohamed Elsafi Mabrouk
- Molecular, Macromolecular Chemistry and Materials, C3M, ESPCI Paris, CNRS, PSL University, 10 rue Vauquelin, 75005 Paris, France
| | - Pierre Marquaille
- Molecular, Macromolecular Chemistry and Materials, C3M, ESPCI Paris, CNRS, PSL University, 10 rue Vauquelin, 75005 Paris, France
| | - Clément Odier
- Molecular, Macromolecular Chemistry and Materials, C3M, ESPCI Paris, CNRS, PSL University, 10 rue Vauquelin, 75005 Paris, France
| | - Sophie Norvez
- Molecular, Macromolecular Chemistry and Materials, C3M, ESPCI Paris, CNRS, PSL University, 10 rue Vauquelin, 75005 Paris, France
| | - Emmanuel Pauthe
- Équipe de Recherche sur les Relations Matrice Extracellulaire-Cellule, ERRMECe, CY Cergy Paris Université, Maison Internationale de la Recherche, 1 rue Descartes, 95000 Neuville-sur-Oise, France
| | - Laurent Corté
- Molecular, Macromolecular Chemistry and Materials, C3M, ESPCI Paris, CNRS, PSL University, 10 rue Vauquelin, 75005 Paris, France; Centre des Matériaux, MINES ParisTech, CNRS, PSL University, 63-65 rue Henri-Auguste Desbruères, 91003 Evry, France.
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5
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Disruption of Chromatin Dynamics by Hypotonic Stress Suppresses HR and Shifts DSB Processing to Error-Prone SSA. Int J Mol Sci 2021; 22:ijms222010957. [PMID: 34681628 PMCID: PMC8535785 DOI: 10.3390/ijms222010957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 11/17/2022] Open
Abstract
The processing of DNA double-strand breaks (DSBs) depends on the dynamic characteristics of chromatin. To investigate how abrupt changes in chromatin compaction alter these dynamics and affect DSB processing and repair, we exposed irradiated cells to hypotonic stress (HypoS). Densitometric and chromosome-length analyses show that HypoS transiently decompacts chromatin without inducing histone modifications known from regulated local chromatin decondensation, or changes in Micrococcal Nuclease (MNase) sensitivity. HypoS leaves undisturbed initial stages of DNA-damage-response (DDR), such as radiation-induced ATM activation and H2AX-phosphorylation. However, detection of ATM-pS1981, γ-H2AX and 53BP1 foci is reduced in a protein, cell cycle phase and cell line dependent manner; likely secondary to chromatin decompaction that disrupts the focal organization of DDR proteins. While HypoS only exerts small effects on classical nonhomologous end-joining (c-NHEJ) and alternative end-joining (alt-EJ), it markedly suppresses homologous recombination (HR) without affecting DNA end-resection at DSBs, and clearly enhances single-strand annealing (SSA). These shifts in pathway engagement are accompanied by decreases in HR-dependent chromatid-break repair in the G2-phase, and by increases in alt-EJ and SSA-dependent chromosomal translocations. Consequently, HypoS sensitizes cells to ionizing radiation (IR)-induced killing. We conclude that HypoS-induced global chromatin decompaction compromises regulated chromatin dynamics and genomic stability by suppressing DSB-processing by HR, and allowing error-prone processing by alt-EJ and SSA.
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What do we know about the biology of the emerging fungal pathogen of humans Candida auris? Microbiol Res 2020; 242:126621. [PMID: 33096325 DOI: 10.1016/j.micres.2020.126621] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/25/2020] [Accepted: 10/04/2020] [Indexed: 02/07/2023]
Abstract
Candida auris is a worrisome fungal pathogen of humans which emerged merely about a decade ago. Ever since then the scientific community worked hard to understand clinically relevant traits, such as virulence factors, antifungal resistance mechanisms, and its ability to adhere to human skin and medical devices. Whole-genome sequencing of clinical isolates and epidemiological studies outlining the path of nosocomial outbreaks have been the focus of research into this pathogenic and multidrug-resistant yeast since its first description in 2009. More recently, work was started by several laboratories to explore the biology of C. auris. Here, we review the insights of studies characterizing the mechanisms underpinning antifungal drug resistance, biofilm formation, morphogenetic switching, cell aggregation, virulence, and pathogenicity of C. auris. We conclude that, although some progress has been made, there is still a long journey ahead of us, before we fully understand this novel pathogen. Critically important is the development of molecular tools for C. auris to make this fungus genetically tractable and traceable. This will allow an in-depth molecular dissection of the life cycle of C. auris, of its characteristics while interacting with the human host, and the mechanisms it employs to avoid being killed by antifungals and the immune system.
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7
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Ethanol exposure increases mutation rate through error-prone polymerases. Nat Commun 2020; 11:3664. [PMID: 32694532 PMCID: PMC7374746 DOI: 10.1038/s41467-020-17447-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 06/30/2020] [Indexed: 12/19/2022] Open
Abstract
Ethanol is a ubiquitous environmental stressor that is toxic to all lifeforms. Here, we use the model eukaryote Saccharomyces cerevisiae to show that exposure to sublethal ethanol concentrations causes DNA replication stress and an increased mutation rate. Specifically, we find that ethanol slows down replication and affects localization of Mrc1, a conserved protein that helps stabilize the replisome. In addition, ethanol exposure also results in the recruitment of error-prone DNA polymerases to the replication fork. Interestingly, preventing this recruitment through mutagenesis of the PCNA/Pol30 polymerase clamp or deleting specific error-prone polymerases abolishes the mutagenic effect of ethanol. Taken together, this suggests that the mutagenic effect depends on a complex mechanism, where dysfunctional replication forks lead to recruitment of error-prone polymerases. Apart from providing a general mechanistic framework for the mutagenic effect of ethanol, our findings may also provide a route to better understand and prevent ethanol-associated carcinogenesis in higher eukaryotes. Whereas the toxic effects of ethanol are well-documented, the underlying mechanism is obscure. This study uses the eukaryotic model S. cerevisiae to reveal how exposure to sublethal ethanol concentrations causes DNA replication stress and an increased mutation rate.
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8
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An insight into the folding and stability of Arabidopsis thaliana SOG1 transcription factor under salinity stress in vitro. Biochem Biophys Res Commun 2019; 515:531-537. [PMID: 31176488 DOI: 10.1016/j.bbrc.2019.05.183] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 05/30/2019] [Indexed: 11/20/2022]
Abstract
The present study describes the biophysical characterization of Arabidopsis thaliana SOG1 (SUPPRESSOR OF GAMMA RESPONSE 1) protein, a NAC domain transcription factor which plays central role in DNA damage response pathway, under salinity stress in vitro. Tryptophan fluorescence studies using purified recombinant wild type (full length) AtSOG1 and its N-terminal or C-terminal deletion forms (AtSOG1ΔNAC and AtSOG1ΔCT respectively) have revealed high salinity induced conformational change due to removal of the N-terminal NAC domain. Bis-ANS binding assays indicate that removal of the N-terminal NAC domain increases the surface hydrophobic binding sites, while the C-terminal region of SOG1 also plays important role in regulating the surface hydrophobicity aspects following exposure to high salinity. Circular dichroism (CD) spectral studies have indicated that removal of the N-terminal NAC domain affects the structural conformation of the protein under high salt concentration. Urea-induced equilibrium unfolding studies revealed decreased stability of C-terminal region due to removal of the N-terminal NAC domain. In vitro aggregation studies have indicated higher propensity of aggregation of AtSOG1ΔNAC due to salt treatment. Overall, our results provide evidence for the importance of both N-terminal NAC domain and the C-terminal region in regulating the stability of SOG1 protein under salinity stress in vitro.
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Hosseiniyan Khatibi SM, Zununi Vahed F, Sharifi S, Ardalan M, Mohajel Shoja M, Zununi Vahed S. Osmolytes resist against harsh osmolarity: Something old something new. Biochimie 2019; 158:156-164. [PMID: 30629975 DOI: 10.1016/j.biochi.2019.01.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/03/2019] [Indexed: 12/14/2022]
Abstract
From the halophilic bacteria to human, cells have to survive under the stresses of harsh environments. Hyperosmotic stress is a process that triggers cell shrinkage, oxidative stress, DNA damage, and apoptosis and it potentially contributes to a number of human diseases. Remarkably, by high salts and organic solutes concentrations, a variety of organisms struggle with these conditions. Different strategies have been developed for cellular osmotic adaptations among which organic osmolyte synthesis/accumulation is a conserved once. Osmolytes are naturally occurring solutes used by cells of several halophilic (micro) organisms to preserve cell volume and function. In this review, the osmolytes diversity and their protective roles in harsh hyperosmolar environments from bacteria to human cells are highlighted. Moreover, it provides a close look at mammalian kidney osmoregulation at a molecular level. This review provides a concise view on the recent developments and advancements on the applications of osmolytes. Identification of disease-related osmolytes and their targeted-delivery may be used as a therapeutic measurement for treatment of the pathological conditions and the inherited diseases related to protein misfolding and aggregation. The molecular and cellular aspects of cell adaptation against harsh environmental osmolarity will benefit the development of effective drugs for many diseases.
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Affiliation(s)
| | | | - Simin Sharifi
- Dental and Periodontal Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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10
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Casali CI, Erjavec LC, Fernández-Tome MDC. Sequential and synchronized hypertonicity-induced activation of Rel-family transcription factors is required for osmoprotection in renal cells. Heliyon 2019; 4:e01072. [PMID: 30603705 PMCID: PMC6304461 DOI: 10.1016/j.heliyon.2018.e01072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 10/31/2018] [Accepted: 12/14/2018] [Indexed: 01/28/2023] Open
Abstract
NF-κB and TonEBP belong to the Rel-superfamily of transcription factors. Several specific stimuli, including hypertonicity which is a key factor for renal physiology, are able to activate them. It has been reported that, after hypertonic challenge, NF-κB activity can be modulated by TonEBP, considered as the master regulator of transcriptional activity in the presence of changes in environmental tonicity. In the present work we evaluated whether hypertonicity-induced gene transcription mediated by p65/RelA and TonEBP occurs by an independent action of each transcription factor or by acting together. To do this, we evaluated the expression of their specific target genes and cyclooxygenase-2 (COX-2), a common target of both transcription factors, in the renal epithelial cell line Madin-Darby canine kidney (MDCK) subjected to hypertonic environment. The results herein indicate that hypertonicity activates the Rel-family transcription factors p65/RelA and TonEBP in MDCK cells, and that both are required for hypertonic induction of COX-2 and of their specific target genes. In addition, present data show that p65/RelA modulates TonEBP expression and both colocalize in nuclei of hypertonic cultures of MDCK cells. Thus, a sequential and synchronized action p65/RelA → TonEBP would be necessary for the expression of hypertonicity-induced protective genes.
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Affiliation(s)
- Cecilia I Casali
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Biología Celular y Molecular, Buenos Aires, Argentina.,Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas Prof. Dr. Alejandro C. Paladini (IQUIFIB)-Facultad de Farmacia y Bioquímica, Buenos Aires, Argentina
| | - Luciana C Erjavec
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Biología Celular y Molecular, Buenos Aires, Argentina
| | - María Del Carmen Fernández-Tome
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Ciencias Biológicas, Cátedra de Biología Celular y Molecular, Buenos Aires, Argentina.,Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas Prof. Dr. Alejandro C. Paladini (IQUIFIB)-Facultad de Farmacia y Bioquímica, Buenos Aires, Argentina
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11
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Mohammadinejad R, Moosavi MA, Tavakol S, Vardar DÖ, Hosseini A, Rahmati M, Dini L, Hussain S, Mandegary A, Klionsky DJ. Necrotic, apoptotic and autophagic cell fates triggered by nanoparticles. Autophagy 2019; 15:4-33. [PMID: 30160607 PMCID: PMC6287681 DOI: 10.1080/15548627.2018.1509171] [Citation(s) in RCA: 236] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 07/19/2018] [Accepted: 08/03/2018] [Indexed: 12/15/2022] Open
Abstract
Nanomaterials have gained a rapid increase in use in a variety of applications that pertain to many aspects of human life. The majority of these innovations are centered on medical applications and a range of industrial and environmental uses ranging from electronics to environmental remediation. Despite the advantages of NPs, the knowledge of their toxicological behavior and their interactions with the cellular machinery that determines cell fate is extremely limited. This review is an attempt to summarize and increase our understanding of the mechanistic basis of nanomaterial interactions with the cellular machinery that governs cell fate and activity. We review the mechanisms of NP-induced necrosis, apoptosis and autophagy and potential implications of these pathways in nanomaterial-induced outcomes. Abbreviations: Ag, silver; CdTe, cadmium telluride; CNTs, carbon nanotubes; EC, endothelial cell; GFP, green fluorescent protein; GO, graphene oxide; GSH, glutathione; HUVECs, human umbilical vein endothelial cells; NP, nanoparticle; PEI, polyethylenimine; PVP, polyvinylpyrrolidone; QD, quantum dot; ROS, reactive oxygen species; SiO2, silicon dioxide; SPIONs, superparamagnetic iron oxide nanoparticles; SWCNT, single-walled carbon nanotubes; TiO2, titanium dioxide; USPION, ultra-small super paramagnetic iron oxide; ZnO, zinc oxide.
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Affiliation(s)
- Reza Mohammadinejad
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Amin Moosavi
- Department of Molecular Medicine, Institute of Medical Biotechnology, National Institute for Genetic Engineering and Biotechnology, Tehran, Iran
| | - Shima Tavakol
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Deniz Özkan Vardar
- Sungurlu Vocational High School, Health Programs, Hitit University, Corum, Turkey
| | - Asieh Hosseini
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Marveh Rahmati
- Cancer Biology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Salik Hussain
- Department of Physiology, Pharmacology and Neuroscience, West Virginia University, School of Medicine, Morgantown, WV, USA
| | - Ali Mandegary
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
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Zhuang S, Smart K, Powell C. Impact of Extracellular Osmolality onSaccharomycesYeast Populations during Brewing Fermentations. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2018. [DOI: 10.1094/asbcj-2017-3505-01] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Shiwen Zhuang
- Division of Food Sciences, School of Biosciences, University of Nottingham, Leicestershire, U.K
| | | | - Chris Powell
- Division of Food Sciences, School of Biosciences, University of Nottingham, Leicestershire, U.K
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Cleavage of osmosensitive transcriptional factor NFAT5 by Coxsackieviral protease 2A promotes viral replication. PLoS Pathog 2017; 13:e1006744. [PMID: 29220410 PMCID: PMC5738146 DOI: 10.1371/journal.ppat.1006744] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 12/20/2017] [Accepted: 11/10/2017] [Indexed: 12/16/2022] Open
Abstract
Nuclear factor of activated T cells 5 (NFAT5)/Tonicity enhancer binding protein (TonEBP) is a transcription factor induced by hypertonic stress in the kidney. However, the function of NFAT5 in other organs has rarely been studied, even though it is ubiquitously expressed. Indeed, although NFAT5 was reported to be critical for heart development and function, its role in infectious heart diseases has remained obscure. In this study, we aimed to understand the mechanism by which NFAT5 interferes with infection of Coxsackievirus B3 (CVB3), a major cause of viral myocarditis. Our initial results demonstrated that although the mRNA level of NFAT5 remained constant during CVB3 infection, NFAT5 protein level decreased because the protein was cleaved. Bioinformatic prediction and verification of the predicted site by site-directed mutagenesis experiments determined that the NFAT5 protein was cleaved by CVB3 protease 2A at Glycine 503. Such cleavage led to the inactivation of NFAT5, and the 70-kDa N-terminal cleavage product (p70-NFAT5) exerted a dominant negative effect on the full-length NFAT5 protein. We further showed that elevated expression of NFAT5 to counteract viral protease cleavage, especially overexpression of a non-cleavable mutant of NFAT5, significantly inhibited CVB3 replication. Ectopic expression of NFAT5 resulted in elevated expression of inducible nitric oxide synthase (iNOS), a factor reported to inhibit CVB3 replication. The necessity of iNOS for the anti-CVB3 effect of NFAT5 was supported by the observation that inhibition of iNOS blocked the anti-CVB3 effect of NFAT5. In a murine model of viral myocarditis, we observed that treatment with hypertonic saline or mannitol solution upregulated NFAT5 and iNOS expression, inhibited CVB3 replication and reduced tissue damage in the heart. Taken together, our data demonstrate that the anti-CVB3 activity of NFAT5 is impaired during CVB3 infection due to 2A-mediated cleavage of NFAT5. Thus induction of NFAT5 by hypertonic agents may be a promising strategy for the development of anti-CVB3 therapeutics.
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Warcoin E, Clouzeau C, Brignole-Baudouin F, Baudouin C. Hyperosmolarité : effets intracellulaires et implication dans la sécheresse oculaire. J Fr Ophtalmol 2016; 39:641-51. [DOI: 10.1016/j.jfo.2016.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/27/2016] [Accepted: 07/27/2016] [Indexed: 11/26/2022]
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Rinsing with Saline Promotes Human Gingival Fibroblast Wound Healing In Vitro. PLoS One 2016; 11:e0159843. [PMID: 27441729 PMCID: PMC4956236 DOI: 10.1371/journal.pone.0159843] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 07/08/2016] [Indexed: 11/29/2022] Open
Abstract
Rinsing the mouth with sodium chloride (NaCl) solution is believed to promote healthy gum and improve oral ulcer healing. Scientific evidence to support this assumption is, however, lacking. This study aims to investigate the effect and clarify underlying mechanisms of short-term rinsing with NaCl on human gingival fibroblast (hGFs) wound healing. Isolated primary hGFs and human normal oral keratinocytes (hNOKs) were rinsed with 0–7.2% NaCl for 2 min, 3 times a day. Scratch-tests, trans-well migration assays and MTT activity were performed. mRNA expression was assessed of type-I collagen, fibronectin and FAK. Changes in FAK and F-actin were detected by immunofluorescence. KCl, NaH2PO4, KH2PO4 were used to clarify the molecules involved. Rinsing with 0.9–1.8% NaCl significantly promoted hGFs cell migration but not proliferation. However, it had no effect on hNOKs. Rinsing with 1.8% NaCl significantly up-regulated the expression of type-I collagen and fibronectin. FAK and F-actin, molecules responsible for cytoskeleton re-organization and cell migration, were also up-regulated. Cl- seemed to be essential since rinsing with KCl resulted in a similar effect as noted with NaCl. In conclusion, short-term rinsing with NaCl promoted hGFs migration, and increased the expression of extracellular matrix as well as cytoskeletal proteins. These data strongly support the long held belief in the benefits of using NaCl mouth-rinse.
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The Development of Sugar-Based Anti-Melanogenic Agents. Int J Mol Sci 2016; 17:583. [PMID: 27092497 PMCID: PMC4849039 DOI: 10.3390/ijms17040583] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/12/2016] [Accepted: 04/14/2016] [Indexed: 01/16/2023] Open
Abstract
The regulation of melanin production is important for managing skin darkness and hyperpigmentary disorders. Numerous anti-melanogenic agents that target tyrosinase activity/stability, melanosome maturation/transfer, or melanogenesis-related signaling pathways have been developed. As a rate-limiting enzyme in melanogenesis, tyrosinase has been the most attractive target, but tyrosinase-targeted treatments still pose serious potential risks, indicating the necessity of developing lower-risk anti-melanogenic agents. Sugars are ubiquitous natural compounds found in humans and other organisms. Here, we review the recent advances in research on the roles of sugars and sugar-related agents in melanogenesis and in the development of sugar-based anti-melanogenic agents. The proposed mechanisms of action of these agents include: (a) (natural sugars) disturbing proper melanosome maturation by inducing osmotic stress and inhibiting the PI3 kinase pathway and (b) (sugar derivatives) inhibiting tyrosinase maturation by blocking N-glycosylation. Finally, we propose an alternative strategy for developing anti-melanogenic sugars that theoretically reduce melanosomal pH by inhibiting a sucrose transporter and reduce tyrosinase activity by inhibiting copper incorporation into an active site. These studies provide evidence of the utility of sugar-based anti-melanogenic agents in managing skin darkness and curing pigmentary disorders and suggest a future direction for the development of physiologically favorable anti-melanogenic agents.
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Mazzei L, Docherty NG, Manucha W. Mediators and mechanisms of heat shock protein 70 based cytoprotection in obstructive nephropathy. Cell Stress Chaperones 2015; 20:893-906. [PMID: 26228633 PMCID: PMC4595437 DOI: 10.1007/s12192-015-0622-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 06/24/2015] [Accepted: 07/09/2015] [Indexed: 12/19/2022] Open
Abstract
Urinary heat shock protein 70 (Hsp70) is rapidly increased in patients with clinical acute kidney injury, indicating that it constitutes a component of the endogenous stress response to renal injury. Moreover, experimental models have demonstrated that Hsp70 activation is associated with the cytoprotective actions of several drugs following obstruction, including nitric oxide (NO) donors, geranylgeranylacetone, vitamin D, and rosuvastatin. Discrete and synergistic effects of the biological activities of Hsp70 may explain its cytoprotective role in obstructive nephropathy. Basic studies point to a combination of effects including inhibition of apoptosis and inflammation, repair of damaged proteins, prevention of unfolded protein aggregation, targeting of damaged protein for degradation, and cytoskeletal stabilization as primary effectors of Hsp70 action. This review summarizes our understanding of how the biological actions of Hsp70 may affect renal cytoprotection in the context of obstructive injury. The potential of Hsp70 to be of central importance to the mechanism of action of various drugs that modify the genesis of experimental obstructive nephropathy is considered.
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Affiliation(s)
- Luciana Mazzei
- Área de Farmacología, Departamento de Patología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.
- IMBECU-CONICET (National Council of Scientific and Technical Research of Argentina), Buenos Aires, Argentina.
| | - Neil G Docherty
- Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Walter Manucha
- Área de Farmacología, Departamento de Patología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
- IMBECU-CONICET (National Council of Scientific and Technical Research of Argentina), Buenos Aires, Argentina
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Role of N-glycosylation in renal betaine transport. Biochem J 2015; 470:169-79. [PMID: 26348906 DOI: 10.1042/bj20131031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 06/03/2015] [Indexed: 11/17/2022]
Abstract
The osmolyte and folding chaperone betaine is transported by the renal Na(+)-coupled GABA (γ-aminobutyric acid) symporter BGT-1 (betaine/GABA transporter 1), a member of the SLC6 (solute carrier 6) family. Under hypertonic conditions, the transcription, translation and plasma membrane (PM) insertion of BGT-1 in kidney cells are significantly increased, resulting in elevated betaine and GABA transport. Re-establishing isotonicity involves PM depletion of BGT-1. The molecular mechanism of the regulated PM insertion of BGT-1 during changes in osmotic stress is unknown. In the present study, we reveal a link between regulated PM insertion and N-glycosylation. Based on homology modelling, we identified two sites (Asn(171) and Asn(183)) in the extracellular loop 2 (EL2) of BGT-1, which were investigated with respect to trafficking, insertion and transport by immunogold-labelling, electron microscopy (EM), mutagenesis and two-electrode voltage clamp measurements in Xenopus laevis oocytes and uptake of radiolabelled substrate into MDCK (Madin-Darby canine kidney) and HEK293 (human embryonic kidney) cells. Trafficking and PM insertion of BGT-1 was clearly promoted by N-glycosylation in both oocytes and MDCK cells. Moreover, association with N-glycans at Asn(171) and Asn(183) contributed equally to protein activity and substrate affinity. Substitution of Asn(171) and Asn(183) by aspartate individually caused no loss of BGT-1 activity, whereas the double mutant was inactive, suggesting that N-glycosylation of at least one of the sites is required for function. Substitution by alanine or valine at either site caused a dramatic loss in transport activity. Furthermore, in MDCK cells PM insertion of N183D was no longer regulated by osmotic stress, highlighting the impact of N-glycosylation in regulation of this SLC6 transporter.
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Hyperosmotic stress reduces melanin production by altering melanosome formation. PLoS One 2014; 9:e105965. [PMID: 25170965 PMCID: PMC4149489 DOI: 10.1371/journal.pone.0105965] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 07/29/2014] [Indexed: 01/01/2023] Open
Abstract
Many tissues of the human body encounter hyperosmotic stress. The effect of extracellular osmotic changes on melanin production has not yet been elucidated. In this study, we determined that hyperosmotic stress induced by organic osmolytes results in reduced melanin production in human melanoma MNT-1 cells. Under hyperosmotic stress, few pigmented mature melanosomes were detected, but there was an increase in swollen vacuoles. These vacuoles were stained with an anti-M6PR antibody that recognizes late endosomal components and with anti-TA99 and anti-HMB45 antibodies, implying that melanosome formation was affected by hyperosmotic stress. Electron microscopic analysis revealed that the M6PR-positive swollen vacuoles were multi-layered and contained melanized granules, and they produced melanin when L-DOPA was applied, indicating that these vacuoles were still capable of producing melanin, but the inner conditions were not compatible with melanin production. The vacuolation phenomenon induced by hyperosmotic conditions disappeared with treatment with the PI3K activator 740 Y-P, indicating that the PI3K pathway is affected by hyperosmotic conditions and is responsible for the proper formation and maturation of melanosomes. The microarray analysis showed alterations of the vesicle organization and transport under hyperosmotic stress. Our findings suggest that melanogenesis could be regulated by physiological conditions, such as osmotic pressure.
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Shor E, Fox CA, Broach JR. The yeast environmental stress response regulates mutagenesis induced by proteotoxic stress. PLoS Genet 2013; 9:e1003680. [PMID: 23935537 PMCID: PMC3731204 DOI: 10.1371/journal.pgen.1003680] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/13/2013] [Indexed: 12/26/2022] Open
Abstract
Conditions of chronic stress are associated with genetic instability in many organisms, but the roles of stress responses in mutagenesis have so far been elucidated only in bacteria. Here, we present data demonstrating that the environmental stress response (ESR) in yeast functions in mutagenesis induced by proteotoxic stress. We show that the drug canavanine causes proteotoxic stress, activates the ESR, and induces mutagenesis at several loci in an ESR-dependent manner. Canavanine-induced mutagenesis also involves translesion DNA polymerases Rev1 and Polζ and non-homologous end joining factor Ku. Furthermore, under conditions of chronic sub-lethal canavanine stress, deletions of Rev1, Polζ, and Ku-encoding genes exhibit genetic interactions with ESR mutants indicative of ESR regulating these mutagenic DNA repair processes. Analyses of mutagenesis induced by several different stresses showed that the ESR specifically modulates mutagenesis induced by proteotoxic stress. Together, these results document the first known example of an involvement of a eukaryotic stress response pathway in mutagenesis and have important implications for mechanisms of evolution, carcinogenesis, and emergence of drug-resistant pathogens and chemotherapy-resistant tumors. Cellular capability to mutate its DNA plays an important role in evolution and impinges on medical issues, including acquisition of mutator phenotypes by cancer cells and emergence of drug-resistant pathogens. Whether and how the environment affects rates of mutation has been studied predominantly in the context of environmental agents that damage DNA (e.g. UV and γ-rays). However, it has been observed that conditions of chronic non-DNA-damaging stress (e.g. starvation or heat shock) also increase mutagenesis. It has been shown that in bacteria, activation of the general stress response activates a pro-mutagenic pathway and thus promotes mutagenesis during periods of stress. However, in eukaryotes, so far there has been no evidence of a stress response regulating mutagenesis. In this manuscript we demonstrate that in budding yeast, a model eukaryote, the general environmental stress response (ESR) regulates mutagenesis induced by proteotoxic stress (accumulation of unfolded proteins) at several loci. We also identify two pro-mutagenic DNA metabolic pathways that contribute to this mutagenesis and present genetic data showing that the ESR regulates these pathways. Together, these data advance our understanding of how cellular sensing and responding to environmental cues affect cellular capability for mutagenesis.
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Affiliation(s)
- Erika Shor
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Catherine A. Fox
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, United States of America
| | - James R. Broach
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania, United States of America
- * E-mail:
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Roy S, Choudhury SR, Sengupta DN, Das KP. Involvement of AtPolλ in the repair of high salt- and DNA cross-linking agent-induced double strand breaks in Arabidopsis. PLANT PHYSIOLOGY 2013; 162:1195-210. [PMID: 23660835 PMCID: PMC3668049 DOI: 10.1104/pp.113.219022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 05/06/2013] [Indexed: 05/21/2023]
Abstract
DNA polymerase λ (Pol λ) is the sole member of family X DNA polymerase in plants and plays a crucial role in nuclear DNA damage repair. Here, we report the transcriptional up-regulation of Arabidopsis (Arabidopsis thaliana) AtPolλ in response to abiotic and genotoxic stress, including salinity and the DNA cross-linking agent mitomycin C (MMC). The increased sensitivity of atpolλ knockout mutants toward high salinity and MMC treatments, with higher levels of accumulation of double strand breaks (DSBs) than wild-type plants and delayed repair of DSBs, has suggested the requirement of Pol λ in DSB repair in plants. AtPolλ overexpression moderately complemented the deficiency of DSB repair capacity in atpolλ mutants. Transcriptional up-regulation of major nonhomologous end joining (NHEJ) pathway genes KU80, X-RAY CROSS COMPLEMENTATION PROTEIN4 (XRCC4), and DNA Ligase4 (Lig4) along with AtPolλ in Arabidopsis seedlings, and the increased sensitivity of atpolλ-2/atxrcc4 and atpolλ-2/atlig4 double mutants toward high salinity and MMC treatments, indicated the involvement of NHEJ-mediated repair of salinity- and MMC-induced DSBs. The suppressed expression of NHEJ genes in atpolλ mutants suggested complex transcriptional regulation of NHEJ genes. Pol λ interacted directly with XRCC4 and Lig4 via its N-terminal breast cancer-associated C terminus (BRCT) domain in a yeast two-hybrid system, while increased sensitivity of BRCT-deficient Pol λ-expressing transgenic atpolλ-2 mutants toward genotoxins indicated the importance of the BRCT domain of AtPolλ in mediating the interactions for processing DSBs. Our findings provide evidence for the direct involvement of DNA Pol λ in the repair of DSBs in a plant genome.
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Affiliation(s)
- Sujit Roy
- Protein Chemistry Laboratory, Department of Chemistry, Bose Institute, Kolkata 700 009, West Bengal, India.
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Yang M, Gao F, Liu H, Yu WH, Zhuo F, Qiu GP, Ran JH, Sun SQ. Hyperosmotic induction of aquaporin expression in rat astrocytes through a different MAPK pathway. J Cell Biochem 2013; 114:111-9. [PMID: 22886825 DOI: 10.1002/jcb.24308] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 07/26/2012] [Indexed: 11/08/2022]
Abstract
Water homeostasis of the nervous system is important during neural signal transduction. Astrocytes are crucial in water transport in the central nervous system under both physiological and pathological conditions. To date, five aquaporins (AQP) have been found in rat brain astrocytes. Most studies have focused on AQP4 and AQP9, however, little is known about the expression of AQP3, -5, and -8 as well as their regulating mechanism in astrocytes. The expression patterns of AQP3, -5, and -8 in astrocytes exposed to hyperosmotic solutions were examined to clarify the roles of AQP3, -5, and -8 in astrocyte water movement. The expression of AQP4 and AQP9 under the same hyperosmotic conditions was also investigated. The AQP4 and AQP9 expressions continuously increased until 12 h after hyperosmotic solution exposure, whereas the AQP3, -5, and -8 expressions continued to increase until 6 h after hyperosmotic solution exposure. The different AQPs decreased at corresponding time points (24 h for AQP4 and AQP9; 12 h for AQP3, -5, and -8 after hyperosmotic solution exposure). The ERK inhibitor can attenuate the expression of AQP3, -5, and -8 after hyperosmotic solution exposure. The p38 inhibitor can inhibit the AQP4 and AQP9 expressions in cultured astrocytes. AQP expression is directly related to the extracellular hyperosmotic stimuli. Moreover, different AQPs can be regulated by a distinct MAPK signal transduction pathway.
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Affiliation(s)
- Mei Yang
- Institute of Neuroscience, Chongqing Medical University, Chongqing 400016, People's Republic of China
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Casali CI, Weber K, Favale NO, Tome MCF. Environmental hyperosmolality regulates phospholipid biosynthesis in the renal epithelial cell line MDCK. J Lipid Res 2013; 54:677-691. [PMID: 23269393 PMCID: PMC3617943 DOI: 10.1194/jlr.m031500] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 12/14/2012] [Indexed: 12/29/2022] Open
Abstract
Hyperosmolality is a key signal for renal physiology. On the one hand, it contributes to the differentiation of renal medullary structures and to the development of the urinary concentrating mechanism. On the other, it is a stress factor. In both cases, hyperosmolality activates processes that require an adequate extension of cellular membranes. In the present work, we examined whether hyperosmolality regulates phospholipid biosynthesis, which is needed for the membrane biogenesis in the renal epithelial cell line Madin-Darby canine kidney (MDCK). Because phospholipids are the structural determinants of all cell membranes, we evaluated their content, synthesis, and regulation in MDCK cultures subjected to different hyperosmotic concentrations of NaCl, urea, or both. Hyperosmolality increased phospholipid content in a concentration-dependent manner. Such an effect was exclusively due to changes in NaCl concentration and occurred at the initial stage of hyperosmolar treatment concomitantly with the expression of the osmoprotective protein COX-2. The hypertonic upregulation of phosphatidylcholine (PC) synthesis, the main constituent of all cell membranes, involved the transcriptional activation of two main regulatory enzymes, choline kinase (CK) and cytidylyltransferase α (CCTα) and required ERK1/2 activation. Considering that physiologically, renal medullary cells are constantly exposed to high and variable NaCl, these findings could contribute to explaining how renal cells could maintain cellular integrity even in a nonfavorable environment.
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Affiliation(s)
- Cecilia I. Casali
- Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires, IQUIFIB–CONICET, Ciudad Autónoma de Buenos Aires (C1113AAD), Argentina
| | - Karen Weber
- Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires, IQUIFIB–CONICET, Ciudad Autónoma de Buenos Aires (C1113AAD), Argentina
| | - Nicolás O. Favale
- Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires, IQUIFIB–CONICET, Ciudad Autónoma de Buenos Aires (C1113AAD), Argentina
| | - María C. Fernández Tome
- Department of Biological Sciences, School of Pharmacy and Biochemistry, University of Buenos Aires, IQUIFIB–CONICET, Ciudad Autónoma de Buenos Aires (C1113AAD), Argentina
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Xiao Z, Shan J, Li C, Luo L, Lu J, Li S, Long D, Li Y. Mechanisms of cyclosporine-induced renal cell apoptosis: a systematic review. Am J Nephrol 2012; 37:30-40. [PMID: 23295863 DOI: 10.1159/000345988] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Accepted: 11/21/2012] [Indexed: 02/05/2023]
Abstract
BACKGROUND/AIMS Chronic cyclosporine A (CsA) nephrotoxicity (CCN) is an important cause of chronic renal dysfunction with no effective clinical intervention. To further elucidate the mechanisms of renal cell apoptosis in CCN, all relevant in vivo studies on this subject were analyzed. METHODS We searched for in vivo studies on the mechanisms of CsA-induced renal cell apoptosis in Medline (1966-July 2010), Embase (1980-July 2010) and ISI (1986-July 2010). The studies were evaluated for their quality according to a set of in vivo standards, data extracted according to PICOS, and then synthesized. RESULTS Renal cell apoptosis was an important feature of CCN and an important factor of renal dysfunction. First, CsA could upregulate Fas/Fas ligand, downregulate Bcl-2/Bcl-XL, and increase caspase-1 and caspase-3. Second, it could induce oxidative stress and damage the antioxidant defense system. Third, it could increase endoplasmic reticulum stress protein in a dose- and time-dependent manner. Fourth, CsA could impair the urine concentration and decrease the expression of hypertonicity-induced genes. Fifth, CsA-induced renal cell apoptosis was significantly decreased by blocking the angiotensin II type 1 receptor using losartan. CONCLUSIONS The in vivo mechanisms for CCN are more complex than those found in vitro. CsA can induce renal cell apoptosis using five pathways in vivo and activated caspases might be the ultimate intersection of these pathways and the common intracellular pathway mediating apoptosis. These data provide new potential points for intervention and need to be confirmed by further studies.
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Affiliation(s)
- Zheng Xiao
- Key Laboratory of Transplant Engineering and Immunology of the Ministry of Health of China, West China Hospital, Sichuan University, Chengdu, PR China
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Hypertonic stress regulates amino acid transport and cell cycle proteins in chick embryo hepatocytes. Cell Biol Int 2012; 36:203-13. [PMID: 21906028 DOI: 10.1042/cbi20100671] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hyperosmotic stress affects cell growth, decreasing cell volume and increasing the uptake of organic osmolytes. However, the sensitivity of embryonic cells to osmotic treatment remains to be established. We have analysed some aspects of cell-cycle control and amino-acid transport in hypertonic conditions during prenatal life. The effects of hyperosmotic stress on amino-acid uptake mediated by system A, (3)H-thymidine incorporation, and regulation of cell-cycle proteins were analysed in chick embryo hepatocytes. Hypertonic stress increased system A activity and caused cell-cycle delay. Effects on amino-acid transport involved p38 kinase activation and new carrier synthesis. Cyclin D1, cdk4 (cyclin-dependent kinase 4) and PCNA (proliferating-cell nuclear antigen) levels decreased, whereas cyclin E, p21 and p53 levels were unchanged. Incorporation of (3)H-leucine indicated decreased synthesis of cyclin D1. In contrast, analysis of mRNA by qRT-PCR (quantitative real-time PCR) showed a net increase of cyclin D1 transcripts, suggesting post-transcriptional regulation. The data show that chick embryo hepatocytes respond to hyperosmotic conditions by arresting cell growth to prevent DNA damage and increasing osmolyte uptake to regulate cell volume, indicating that the adaptive response to environmental stress exists during prenatal life.
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Ortells MC, Morancho B, Drews-Elger K, Viollet B, Laderoute KR, López-Rodríguez C, Aramburu J. Transcriptional regulation of gene expression during osmotic stress responses by the mammalian target of rapamycin. Nucleic Acids Res 2012; 40:4368-84. [PMID: 22287635 PMCID: PMC3378878 DOI: 10.1093/nar/gks038] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although stress can suppress growth and proliferation, cells can induce adaptive responses that allow them to maintain these functions under stress. While numerous studies have focused on the inhibitory effects of stress on cell growth, less is known on how growth-promoting pathways influence stress responses. We have approached this question by analyzing the effect of mammalian target of rapamycin (mTOR), a central growth controller, on the osmotic stress response. Our results showed that mammalian cells exposed to moderate hypertonicity maintained active mTOR, which was required to sustain their cell size and proliferative capacity. Moreover, mTOR regulated the induction of diverse osmostress response genes, including targets of the tonicity-responsive transcription factor NFAT5 as well as NFAT5-independent genes. Genes sensitive to mTOR-included regulators of stress responses, growth and proliferation. Among them, we identified REDD1 and REDD2, which had been previously characterized as mTOR inhibitors in other stress contexts. We observed that mTOR facilitated transcription-permissive conditions for several osmoresponsive genes by enhancing histone H4 acetylation and the recruitment of RNA polymerase II. Altogether, these results reveal a previously unappreciated role of mTOR in regulating transcriptional mechanisms that control gene expression during cellular stress responses.
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Affiliation(s)
- M Carmen Ortells
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, 08003 Barcelona, Spain
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Mavrogonatou E, Kletsas D. Differential response of nucleus pulposus intervertebral disc cells to high salt, sorbitol, and urea. J Cell Physiol 2011; 227:1179-87. [DOI: 10.1002/jcp.22840] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Havard M, Dautry F, Tchénio T. A dormant state modulated by osmotic pressure controls clonogenicity of prostate cancer cells. J Biol Chem 2011; 286:44177-44186. [PMID: 22039055 DOI: 10.1074/jbc.m111.262709] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cell dormancy constitutes a limiting step of the metastatic process by preventing the proliferation of isolated cancer cells disseminated at distant sites from the primary tumor. The study of cancer cell dormancy is severely hampered by the lack of biological samples so that the mechanisms that regulate cell dormancy have not been extensively explored. In this work, we describe the rapid induction in vitro of a dormant state in prostate cancer cells by exposure to a slightly hypertonic growth medium. This quiescence is observed only when cells are seeded at low density and, once established, requires additional stimuli besides osmotic pressure to be reversed. Media conditioned by cells grown at high density can partially prevent or reverse dormancy, a phenomenon which can be reproduced with citric acid. In addition to this role of small metabolites, inactivation of the p53 and smad pathways also counters the entry into dormancy, whereas exposure to activin A induces it to some extent. Thus, this easily inducible dormancy reproduces several features associated with the dormancy of stem cells and cancer cells in vivo.
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Affiliation(s)
- Maryline Havard
- Laboratoire de Biologie et de Pharmacologie Appliquée, Centre National de la Recherche Scientifique, UMR8113, Ecole Normale Supérieure de Cachan, 94235 Cachan Cedex, France
| | - François Dautry
- Laboratoire de Biologie et de Pharmacologie Appliquée, Centre National de la Recherche Scientifique, UMR8113, Ecole Normale Supérieure de Cachan, 94235 Cachan Cedex, France
| | - Thierry Tchénio
- Laboratoire de Biologie et de Pharmacologie Appliquée, Centre National de la Recherche Scientifique, UMR8113, Ecole Normale Supérieure de Cachan, 94235 Cachan Cedex, France.
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Portt L, Norman G, Clapp C, Greenwood M, Greenwood MT. Anti-apoptosis and cell survival: a review. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:238-59. [PMID: 20969895 DOI: 10.1016/j.bbamcr.2010.10.010] [Citation(s) in RCA: 430] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 10/04/2010] [Accepted: 10/11/2010] [Indexed: 02/08/2023]
Abstract
Type I programmed cell death (PCD) or apoptosis is critical for cellular self-destruction for a variety of processes such as development or the prevention of oncogenic transformation. Alternative forms, including type II (autophagy) and type III (necrotic) represent the other major types of PCD that also serve to trigger cell death. PCD must be tightly controlled since disregulated cell death is involved in the development of a large number of different pathologies. To counter the multitude of processes that are capable of triggering death, cells have devised a large number of cellular processes that serve to prevent inappropriate or premature PCD. These cell survival strategies involve a myriad of coordinated and systematic physiological and genetic changes that serve to ward off death. Here we will discuss the different strategies that are used to prevent cell death and focus on illustrating that although anti-apoptosis and cellular survival serve to counteract PCD, they are nevertheless mechanistically distinct from the processes that regulate cell death.
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Affiliation(s)
- Liam Portt
- Department of Chemistry and Chemical Engineering, Royal Military College, Ontario, Canada
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Andres-Hernando A, Lanaspa MA, Li N, Cicerchi C, Roncal-Jimenez C, Cantor GH, Sorribas V, Rivard CJ, Berl T. Effects of 2-bromoethanamine on TonEBP expression and its possible role in induction of renal papillary necrosis in mice. Toxicol Sci 2010; 118:510-20. [PMID: 20823374 DOI: 10.1093/toxsci/kfq261] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Chronic analgesic abuse has been shown to induce severe renal injury characterized by renal papillary necrosis (RPN), an injury detectable at late stage. While direct toxicity of the drug may exist, the molecular mechanisms underlying analgesics induction of RPN remain unknown. A major limitation to study the pathogenesis of RPN is the required chronic exposure before detection of injury. Here, we employed 2-bromoethanamine (BEA) to simulate rapid papillary toxicity using inner medullary collecting duct (IMCD3) cells. Although exposure to 10μM BEA had no effect on cellular viability under isotonic conditions, a 50% loss in cell viability was observed in the first 24 h when cells were subjected to sublethal hypertonic stress and nearly complete cell death after 48 h suggesting that BEA exerts cytotoxicity only under hypertonic conditions. Because TonEBP is a transcription factor critical for cell survival during hypertonic conditions, we undertook experiments to examine the effect of BEA on TonEBP expression and activity. Exposure of cells to 10μM BEA resulted in a substantial reduction in TonEBP protein expression after 24 h. In addition, TonEBP was not translocated to the nucleus in BEA-treated IMCD3 cells under acute hypertonic stress for transcription of target genes essential for osmolyte accumulation. Finally, we found a substantial decrease in TonEBP expression in medullary kidney tissues of mice injected with a single ip dose of BEA. Our data suggest that TonEBP is a potential target for BEA leading to the process of papillary necrosis in the settings of hypertonic stress.
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Affiliation(s)
- Ana Andres-Hernando
- Division of Renal Diseases and Hypertension, School of Medicine, University of Colorado Denver, Aurora, Colorado 80045, USA
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Lee EC, Maresh CM, Kraemer WJ, Yamamoto LM, Hatfield DL, Bailey BL, Armstrong LE, Volek JS, McDermott BP, Craig SA. Ergogenic effects of betaine supplementation on strength and power performance. J Int Soc Sports Nutr 2010; 7:27. [PMID: 20642826 PMCID: PMC2915951 DOI: 10.1186/1550-2783-7-27] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Accepted: 07/19/2010] [Indexed: 01/07/2023] Open
Abstract
Background We investigated the ergogenic effects of betaine (B) supplementation on strength and power performance. Methods Twelve men (mean ± SD age, 21 ± 3 yr; mass, 79.1 ± 10.7 kg) with a minimum of 3 months resistance training completed two 14-day experimental trials separated by a 14-day washout period, in a balanced, randomized, double-blind, repeated measures, crossover design. Prior to and following 14 days of twice daily B or placebo (P) supplementation, subjects completed two consecutive days (D1 and D2) of a standardized high intensity strength/power resistance exercise challenge (REC). Performance included bench, squat, and jump tests. Results Following 14-days of B supplementation, D1 and D2 bench throw power (1779 ± 90 and 1788 ± 34 W, respectively) and isometric bench press force (2922 ± 297 and 2503 ± 28 N, respectively) were increased (p < 0.05) during REC compared to pre-supplementation values (1534 ± 30 and 1498 ± 29 W, respectively; 2345 ± 64 and 2423 ± 84 N, respectively) and corresponding P values (1374 ± 128 and 1523 ± 39 W; 2175 ± 92 and 2128 ± 56 N, respectively). Compared to pre-supplementation, vertical jump power and isometric squat force increased (p < 0.05) on D1 and D2 following B supplementation. However, there were no differences in jump squat power or the number of bench press or squat repetitions. Conclusion B supplementation increased power, force and maintenance of these measures in selected performance measures, and these were more apparent in the smaller upper-body muscle groups.
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Affiliation(s)
- Elaine C Lee
- Department of Kinesiology, University of Connecticut, Storrs, CT, USA.
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Lever M, Slow S. The clinical significance of betaine, an osmolyte with a key role in methyl group metabolism. Clin Biochem 2010; 43:732-44. [DOI: 10.1016/j.clinbiochem.2010.03.009] [Citation(s) in RCA: 273] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 03/16/2010] [Accepted: 03/17/2010] [Indexed: 01/29/2023]
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Lanaspa MA, Andres-Hernando A, Rivard CJ, Dai Y, Li N, Berl T. ZAC1 is up-regulated by hypertonicity and decreases sorbitol dehydrogenase expression, allowing accumulation of sorbitol in kidney cells. J Biol Chem 2009; 284:19974-81. [PMID: 19423711 PMCID: PMC2740423 DOI: 10.1074/jbc.m109.001792] [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: 04/02/2009] [Revised: 05/01/2009] [Indexed: 01/09/2023] Open
Abstract
Affymetrix GeneChip technology was employed to detect differentially expressed genes in inner medullary collecting duct (IMCD3) cells grown under isotonic and hypertonic conditions. A marked up-regulation was found for the zinc-finger protein ZAC1 under hypertonic stress (219-fold, p < 0.001). Changes in expression for ZAC1 were verified by quantitative PCR for message and Western blotting for protein. In mouse and human kidney tissues, ZAC1 expression was substantial in the papilla and was absent in the cortex. Furthermore, ZAC1 expression significantly increased in the papilla of mice following 36 h of fluid restriction and decreased in polyuric mice consuming sucrose in water. Because ZAC1 has been described to be a potential negative regulator of sorbitol dehydrogenase (SDH) in hippocampal cells, we examined whether this relationship also occurs in kidney cells under hypertonic stress. We found that stable IMCD3 clones silenced for ZAC1 to varying levels demonstrated an inverse effect on SDH expression. ZAC1 binds to a consensus repression site within the promoter of SDH, pointing to a mechanism whereby ZAC1 acts by repressing SDH transcriptional activity during hypertonic conditions. Taken together, these data strongly suggest that ZAC1 is up-regulated under hypertonic stress and negatively regulates expression of SDH, allowing for accumulation of sorbitol as a compatible organic osmolyte.
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Affiliation(s)
- Miguel A. Lanaspa
- From the Department of Renal Diseases and Hypertension, University of Colorado Health Sciences Center, Aurora, Colorado 80045
| | - Ana Andres-Hernando
- From the Department of Renal Diseases and Hypertension, University of Colorado Health Sciences Center, Aurora, Colorado 80045
| | - Christopher J. Rivard
- From the Department of Renal Diseases and Hypertension, University of Colorado Health Sciences Center, Aurora, Colorado 80045
| | - Yue Dai
- From the Department of Renal Diseases and Hypertension, University of Colorado Health Sciences Center, Aurora, Colorado 80045
| | - Nanxing Li
- From the Department of Renal Diseases and Hypertension, University of Colorado Health Sciences Center, Aurora, Colorado 80045
| | - Tomas Berl
- From the Department of Renal Diseases and Hypertension, University of Colorado Health Sciences Center, Aurora, Colorado 80045
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The transcription factor NFAT5 is required for cyclin expression and cell cycle progression in cells exposed to hypertonic stress. PLoS One 2009; 4:e5245. [PMID: 19381288 PMCID: PMC2667631 DOI: 10.1371/journal.pone.0005245] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Accepted: 03/19/2009] [Indexed: 11/20/2022] Open
Abstract
Background Hypertonicity can perturb cellular functions, induce DNA damage-like responses and inhibit proliferation. The transcription factor NFAT5 induces osmoprotective gene products that allow cells to adapt to sustained hypertonic conditions. Although it is known that NFAT5-deficient lymphocytes and renal medullary cells have reduced proliferative capacity and viability under hypertonic stress, less is understood about the contribution of this factor to DNA damage responses and cell cycle regulation. Methodology/Principal Findings We have generated conditional knockout mice to obtain NFAT5−/− T lymphocytes, which we used as a model of proliferating cells to study NFAT5-dependent responses. We show that hypertonicity triggered an early, NFAT5-independent, genotoxic stress-like response with induction of p53, p21 and GADD45, downregulation of cyclins, and cell cycle arrest. This was followed by an NFAT5-dependent adaptive phase in wild-type cells, which induced an osmoprotective gene expression program, downregulated stress markers, resumed cyclin expression and proliferation, and displayed enhanced NFAT5 transcriptional activity in S and G2/M. In contrast, NFAT5−/− cells failed to induce osmoprotective genes and exhibited poorer viability. Although surviving NFAT5−/− cells downregulated genotoxic stress markers, they underwent cell cycle arrest in G1/S and G2/M, which was associated with reduced expression of cyclins E1, A2 and B1. We also show that pathologic hypertonicity levels, as occurring in plasma of patients and animal models of osmoregulatory disorders, inhibited the induction of cyclins and aurora B kinase in response to T cell receptor stimulation in fresh NFAT5−/− lymphocytes. Conclusions/Significance We conclude that NFAT5 facilitates cell proliferation under hypertonic conditions by inducing an osmoadaptive response that enables cells to express fundamental regulators needed for cell cycle progression.
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Aramburu J, López-Rodríguez C. Brx shines a light on the route from hyperosmolarity to NFAT5. Sci Signal 2009; 2:pe20. [PMID: 19351952 DOI: 10.1126/scisignal.265pe20] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Nuclear factor of activated T cells 5 (NFAT5) is a member of the Rel family of transcription factors and is an essential inducer of osmoprotective gene products in mammalian cells. Its activation by hypertonicity requires p38 mitogen-activated protein kinase (MAPK) signaling and other pathways. A study now elucidates a signaling cascade regulated by the guanine nucleotide exchange factor Brx that leads to the activation of p38alpha MAPK and the induction of nfat5 messenger RNA in response to osmotic stress in lymphocytes and renal medullary cells. Brx-deficient lymphocytes showed impaired responses to hypertonicity, and brx(+/-) mice exhibited immune defects similar to those of nfat5-deficient mice. These findings support a major role for Brx in regulating the osmoprotective function of NFAT5 in different cell types.
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Affiliation(s)
- Jose Aramburu
- Immunology Unit, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, 08003 Barcelona, Spain.
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Hasler U. Controlled aquaporin-2 expression in the hypertonic environment. Am J Physiol Cell Physiol 2009; 296:C641-53. [PMID: 19211910 DOI: 10.1152/ajpcell.00655.2008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The corticomedullary osmolality gradient is the driving force for water reabsorption occurring in the kidney. In the collecting duct, this gradient allows luminal water to move across aquaporin (AQP) water channels, thereby increasing urine concentration. However, this same gradient exposes renal cells to great osmotic challenges. These cells must constantly adapt to fluctuations of environmental osmolality that challenge cell volume and incite functional change. This implies profound alterations of cell phenotype regarding water permeability. AQP2 is an essential component of the urine concentration mechanism whose controlled expression dictates apical water permeability of collecting duct principal cells. This review focuses on changes of AQP2 abundance and trafficking in hypertonicity-challenged cells. Intracellular mechanisms governing these events are discussed and the biological relevance of altered AQP2 expression by hypertonicity is outlined.
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Affiliation(s)
- Udo Hasler
- Service de Néphrologie, Fondation pour Recherches Médicales, 64 Ave. de la Roseraie, CH-1211, Geneva 4, Switzerland.
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Alonso G, Galibert E, Boulay V, Guillou A, Jean A, Compan V, Guillon G. Sustained elevated levels of circulating vasopressin selectively stimulate the proliferation of kidney tubular cells via the activation of V2 receptors. Endocrinology 2009; 150:239-50. [PMID: 18787031 DOI: 10.1210/en.2008-0068] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The hypothalamic hormone vasopressin (AVP) has known mitogenic effects on various cell types. This study was designed to determine whether sustained elevated levels of circulating AVP could influence cell proliferation within adult tissues known to express different AVP receptors, including the pituitary, adrenal gland, liver, and kidney. Plasmatic AVP was chronically increased by submitting animals to prolonged hyperosmotic stimulation or implanting them with a AVP-containing osmotic minipump. After several days of either treatment, increased cell proliferation was detected only within the kidney. This kidney cell proliferation was not affected by the administration of selective V1a or V1b receptor antagonists but was either inhibited or mimicked by the administration of a selective V2 receptor antagonist or agonist, respectively. Kidney proliferative cells mostly concerned a subpopulation of differentiated tubular cells known to express the V2 receptors and were associated with the phosphorylation of ERK. These data indicate that in the adult rat, sustained elevated levels of circulating AVP stimulates the proliferation of a subpopulation of kidney tubular cells expressing the V2 receptor, providing the first illustration of a mitogenic effect of AVP via the activation of the V2 receptor subtype.
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Affiliation(s)
- Gérard Alonso
- Départements d'Endocrinologie, Institut de Génomique Fonctionnelle, 141 Rue de la Cardonille, 34094 Montpellier cedex 05, France
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Manucha W, Vallés P. Hsp70/nitric oxide relationship in apoptotic modulation during obstructive nephropathy. Cell Stress Chaperones 2008; 13:413-20. [PMID: 18563630 PMCID: PMC2673925 DOI: 10.1007/s12192-008-0050-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 04/22/2008] [Accepted: 04/29/2008] [Indexed: 11/25/2022] Open
Abstract
The functional integrity of the kidney depends on normal development as well as on physiological cell turnover. Apoptosis induction is essential for these mechanisms. Multiple mechanisms are unleashed during obstructive nephropathy, one of the most complex being programmed cell death that leads to renal tubular atrophy and tubular loss. This review will focus on the interaction of nitric oxide and Hsp70 and on the regulation of renal antiapoptotic and protective oxidative stress responses.
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Affiliation(s)
- Walter Manucha
- Área de Fisiología Patológica, Departamento de Patología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Centro Universitario, 5500 Mendoza, Argentina
- IMBECU-CONICET (Consejo Nacional de Investigación Ciencia y Tecnológica), Mendoza, Argentina
| | - Patricia Vallés
- Área de Fisiología Patológica, Departamento de Patología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Centro Universitario, 5500 Mendoza, Argentina
- IMBECU-CONICET (Consejo Nacional de Investigación Ciencia y Tecnológica), Mendoza, Argentina
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Fischer JM, Stringer JR. Mutation in aging mice occurs in diverse cell types that proliferate postmutation. Aging Cell 2008; 7:667-80. [PMID: 18652575 DOI: 10.1111/j.1474-9726.2008.00416.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
To determine the relationship between aging, cell proliferation and mutation in different cell types, hearts, brains and kidneys from G11 PLAP mice between 1 week and 24 months of age were examined. Mutant cells were detected in tissue sections by staining for Placental Alkaline Phosphatase (PLAP) activity, an activity that marks cells that have sustained a frameshift mutation in a mononucleotide tract inserted into the coding region of the human gene encoding PLAP. The number of PLAP(+) cells increased with age in all three tissues. The types of cells exhibiting a mutant phenotype included cells that are proliferative, such as kidney epithelial cells, and cells that do not frequently replicate, such as cardiac muscle cells and neurons. In the brain, PLAP(+) cells appeared in various locations and occurred at similar frequencies in different regions. Within the cerebellum, PLAP(+) Purkinje cell neurons appeared at a rate similar to that seen in the brain as a whole. PLAP(+) cells were observed in kidney-specific cell types such as those in glomeruli and collecting tubules, as well as in connective tissue and blood vessels. In the heart, PLAP(+) cells appeared to be cardiac muscle cells. Regardless of tissue and cell type, PLAP(+) cells occurred as singletons and in clusters, both of which increased in frequency with age. These data show that age-associated accumulation of mutant cells occurs in diverse cell types and is due to both new mutation and proliferation of mutant cells, even in cell types that tend to not proliferate.
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Hyperosmotic stress up-regulates the expression of major vault protein in SW620 human colon cancer cells. Exp Cell Res 2008; 314:3017-26. [PMID: 18671966 DOI: 10.1016/j.yexcr.2008.07.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Revised: 07/01/2008] [Accepted: 07/01/2008] [Indexed: 01/05/2023]
Abstract
The major vault protein (MVP) is the major constituent of the vault particle, the largest ribonuclear protein complex described to date and is identical to lung resistance-related protein (LRP). Although MVP is also expressed in several normal tissues, little is known about its physiological role. MVP played a protective role against some xenobiotics and other stresses. We thus investigated the effect of osmotic stress on MVP expression by treating human colon cancer SW620 cells with sucrose or NaCl. The expression level of both MVP protein and MVP mRNA was increased by the osmostress. Sucrose or sodium chloride could also enhance MVP promoter activity. Inhibition of p38 MAPK in SW620 cells by SB203580 inhibited the expression of MVP under hyperosmotic stress. These findings suggested that osmotic stress up-regulated the MVP expression through p38 MAPK pathway. Down-regulation of MVP expression by MVP interfering RNA (RNAi) in SW620 cells increased the sensitivity of the cells to hyperosmotic stress and enhanced apoptosis. Furthermore, MVP RNAi prevented the osmotic stress-induced, time-dependent increase in phosphorylated Akt. These findings suggest that the PI3K/Akt pathway might be implicated in the cytoprotective effect of MVP. Our data demonstrate that exposure of cells to hyperosmotic stress induces MVP that might play an important role in the protection of the cells from the adverse effects of osmotic stress.
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Andres-Hernando A, Lanaspa MA, Rivard CJ, Berl T. Nucleoporin 88 (Nup88) is regulated by hypertonic stress in kidney cells to retain the transcription factor tonicity enhancer-binding protein (TonEBP) in the nucleus. J Biol Chem 2008; 283:25082-90. [PMID: 18606815 DOI: 10.1074/jbc.m802381200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Antibody microarray technology identified Nup88 (nucleoporin 88) as a highly up-regulated protein in response to osmotic stress in inner medullary collecting duct (IMCD3) cells. Changes in expression were verified by Western blot and quantitative PCR for protein and message expression. In mouse and human kidney, Nup88 expression was substantial in the papilla, whereas it was nearly absent in the cortex. Furthermore, the expression of Nup88 increased 410.4 +/- 22% in the papilla of mice after 36 h of thirsting. Nup88 protein expression in IMCD3 cells was significantly up-regulated in the first 8 h following exposure to acute osmotic stress, indicating that Nup88 is an early response protein. To define the function of Nup88 in the osmotic stress response, the transcription factor associated with hypertonicity, tonicity enhancer-binding protein (TonEBP), was cloned upstream of the green fluorescent protein. Employing this construct, we demonstrate that silencing Nup88 in IMCD3 cells acutely stressed to hypertonic conditions reduces nuclear retention of TonEBP, resulting in a substantial blunting in transcription of important osmotic stress response target genes and reduced cell viability. Finally, we show that in IMCD3 cells, nuclear export of TonEBP under isotonic conditions involves CRM-1 but under hypertonic stress is CRM1-independent. Our data, therefore, suggest that Nup88 is up-regulated in response to hypertonic stress and acts to retain TonEBP in the nucleus, activating transcription of critical osmoprotective genes.
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Affiliation(s)
- Ana Andres-Hernando
- Division of Renal Diseases and Hypertension, School of Medicine, University Colorado Health Sciences Center, Denver, Colorado 80262, USA
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42
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Nakaya T, Kawai T, Suzuki T. Regulation of FE65 nuclear translocation and function by amyloid beta-protein precursor in osmotically stressed cells. J Biol Chem 2008; 283:19119-31. [PMID: 18468999 DOI: 10.1074/jbc.m801827200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
FE65, a neural adaptor protein, interacts with amyloid beta-protein precursor (APP) and is known to regulate amyloid beta generation from APP. FE65 also associates with nuclear proteins; however, its physiological function in the nucleus remains unclear. A fixed population of cytoplasmic FE65 is tethered to membranes by binding APP. This membrane-tethered FE65 is liberated from membranes by APP phosphorylation, which is facilitated by a stress-activated protein kinase in sorbitol-treated cells. Here we show that liberated FE65, which is distinct from "virgin" FE65 in the cytoplasm, translocates into the nucleus and accumulates in the nuclear matrix forming a patched structure. Targeting of FE65 into the nuclear matrix was suppressed by the APP intracellular domain fragment, which is generated by consecutive cleavages of APP. Thus, nuclear translocation of FE65 is under the regulation of APP. In the nucleus, FE65 induced gammaH2AX, which plays an important role in DNA repair as a cellular response by stress-damaged cells. These observations suggest that APP-regulated FE65 plays an important role in the early stress response of cells and that FE65 deregulated from APP induces apoptosis.
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Affiliation(s)
- Tadashi Nakaya
- Laboratory of Neuroscience, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12 Nishi-6, Kita-ku, Sapporo 060-0812, Japan
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Schliess F, Reinehr R, Häussinger D. Osmosensing and signaling in the regulation of mammalian cell function. FEBS J 2007; 274:5799-803. [DOI: 10.1111/j.1742-4658.2007.06100.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Niimura Y, Nagai KI. Metabolic responses of sulfatide and related glycolipids in Madin-Darby canine kidney (MDCK) cells under osmotic stresses. Comp Biochem Physiol B Biochem Mol Biol 2007; 149:161-7. [PMID: 17905621 DOI: 10.1016/j.cbpb.2007.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Revised: 09/05/2007] [Accepted: 09/06/2007] [Indexed: 11/20/2022]
Abstract
Incorporation of (35)S-sulfate into the polar molecular species of sulfoglycolipids (SM4s) in Madin-Darby canine kidney cells increased in a hypertonic medium (500 mOsm/L) supplemented with sodium chloride. The unknown sulfoglycolipid (SX) was identified as GlcCer sulfate based on the results of TLC, GLC, and mass spectra. The synthesis of SX increased in the hypotonic medium unlike that of SM4s and SM3. TLC showed that hypertonic stress induced the accumulation of GalCer as a precursor of SM4s, whereas hypotonic stress increased GlcCer as a precursor of GlcCer sulfate. The level of ceramide as a precursor of both GalCer and GlcCer increased under hypertonic stress and decreased under hypotonic stress. Cerebroside sulfotransferase mRNA was shown to be elevated in the hyperosmotic condition but not in the hypotonic condition. The increase in SM4s under hypertonic stress was induced by the activation of both the ceramide galactosyltransferase and the cerebroside sulfotransferase genes, whereas the increase in GlcCer sulfate under hypotonic stress was caused by the accumulation of GlcCer as the result of activation of ceramide glucosyltransferase.
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Affiliation(s)
- Yukio Niimura
- Research Center of Biomedical Analysis and Radioisotope, Teikyo University School of Medicine, 2-11-1 Kaga Itabashi-ku, Tokyo 173-8605, Japan.
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45
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Alao JP. The regulation of cyclin D1 degradation: roles in cancer development and the potential for therapeutic invention. Mol Cancer 2007; 6:24. [PMID: 17407548 PMCID: PMC1851974 DOI: 10.1186/1476-4598-6-24] [Citation(s) in RCA: 618] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Accepted: 04/02/2007] [Indexed: 12/15/2022] Open
Abstract
Cyclin D1 is an important regulator of cell cycle progression and can function as a transcriptionl co-regulator. The overexpression of cyclin D1 has been linked to the development and progression of cancer. Deregulated cyclin D1 degradation appears to be responsible for the increased levels of cyclin D1 in several cancers. Recent findings have identified novel mechanisms involved in the regulation of cyclin D1 stability. A number of therapeutic agents have been shown to induce cyclin D1 degradation. The therapeutic ablation of cyclin D1 may be useful for the prevention and treatment of cancer. In this review, current knowledge on the regulation of cyclin D1 degradation is discussed. Novel insights into cyclin D1 degradation are also discussed in the context of ablative therapy. A number of unresolved questions regarding the regulation of cellular cyclin D1 levels are also addressed.
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Affiliation(s)
- John P Alao
- Department of Cell and Molecular Biology, Lundberg Laboratory, Gothenburg University, Gothenburg, Sweden.
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Ernest NJ, Sontheimer H. Extracellular glutamine is a critical modulator for regulatory volume increase in human glioma cells. Brain Res 2007; 1144:231-8. [PMID: 17320059 PMCID: PMC1899165 DOI: 10.1016/j.brainres.2007.01.085] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Revised: 01/24/2007] [Accepted: 01/24/2007] [Indexed: 11/18/2022]
Abstract
Mammalian cells regulate their volume to prevent unintentional changes in intracellular signaling, cell metabolism, and DNA integrity. Intentional cell volume changes occur as cells undergo proliferation, apoptosis, or cell migration. To regulate cell volume, cells use channels and transport systems to flux osmolytes across the plasma membrane followed by the obligatory movement of water. While essentially all cells are capable of regulatory volume decrease (RVD), regulatory volume increase (RVI) mechanisms have only been reported in some cell types. In this investigation, we used human glioma cells as a model system to determine conditions necessary for RVI. When exposed to hyperosmotic conditions through the addition of 30 mosM NaCl or sucrose, D54-MG and U251 glioma cell lines and glioma cells from acute patient biopsies shrunk transiently but were able to fully recover their original cell volume within 40-70 min. This ability was highly temperature sensitive and absolutely required the presence of low millimolar concentrations of l-glutamine in the extracellular solution. Other known substrates of glutamine transporters such as methyl-amino isobutyric acid (MeAIB), alanine, and threonine were unable to support RVI. The ability of cells to undergo RVI also required the presence of Na+, K+, and Cl- and was inhibited by the NKCC inhibitor, bumetanide, consistent with the involvement of a Na+/K+/2Cl- cotransporter (NKCC). Moreover, the expression of NKCC1 was demonstrated by Western blot. We concluded that regulatory volume increase in human glioma cells occurs through the uptake of Na+, K+, and Cl- by NKCC1 and is modulated by the presence of glutamine.
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Affiliation(s)
- Nola Jean Ernest
- Department of Neurobiology, The Civitan International Research Center, University of Alabama at Birmingham, CIRC 425, 1719 6th Avenue South, Birmingham, AL 35294, USA
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Alfieri RR, Petronini PG. Hyperosmotic stress response: comparison with other cellular stresses. Pflugers Arch 2007; 454:173-85. [PMID: 17206446 DOI: 10.1007/s00424-006-0195-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Accepted: 11/24/2006] [Indexed: 10/23/2022]
Abstract
Cellular responses induced by stress are essential for the survival of cells under adverse conditions. These responses, resulting in cell adaptation to the stress, are accomplished by a variety of processes at the molecular level. After an alteration in homeostatic conditions, intracellular signalling processes link the sensing mechanism to adaptive or compensatory changes in gene expression. The ability of cells to adapt to hyperosmotic stress involves early responses in which ions move across cell membranes and late responses characterized by increased synthesis of either membrane transporters essential for uptake of organic osmolytes or of enzymes involved in their synthesis. The goal of these responses is to return the cell to its normal size and maintain cellular homeostasis. The enhanced synthesis of molecular chaperones, such as heat shock proteins, is another important component of the adaptive process that contributes to cell survival. Some responses are common to different stresses, whereas others are specific. In the first part of the review, we illustrate the characteristic and specific features of adaptive response to hypertonicity; we then describe similarities to and differences from other cellular stresses, such as genotoxic agents, nutrient starvation and heat shock.
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Affiliation(s)
- Roberta R Alfieri
- Dipartimento di Medicina Sperimentale, Sezione di Patologia Molecolare e Immunologia, Università degli Studi di Parma, 43100 Parma, Italy.
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Sheen MR, Kim SW, Jung JY, Ahn JY, Rhee JG, Kwon HM, Woo SK. Mre11-Rad50-Nbs1 complex is activated by hypertonicity. Am J Physiol Renal Physiol 2006; 291:F1014-20. [PMID: 16788144 DOI: 10.1152/ajprenal.00153.2006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
When exposed to hypertonic conditions, cells accumulate double-strand DNA breaks (DSBs) like they are exposed to ionizing radiation. It has been proposed that inactivation of the Mre11-Rad50-Nbs1 (MRN) complex due to nuclear exit is responsible for the accumulation of DSBs as cells fail to repair DSBs produced during normal cellular activity. In this study, we examined the MRN complex in cells switched to hypertonicity. Surprisingly, we found that the MRN complex stayed in the nucleus and remained intact in response to hypertonicity. In fact, the MRN complex was dramatically activated after 4 h of switch to hypertonicity in a dose-dependent manner as shown by formation of foci. Activation of ATM and the MRN complex by hypertonicity and bleomycin was additive as was activation of their downstream targets including gammaH2AX and Chk2 indicating that the cellular response to DSB was intact in hypertonic conditions. Activation of Chk2 in response to hypertonicity was not observed in mutant cells with functionally impaired MRN complex confirming that they are in the same pathway. After 20 h of a switch to hypertonicity, MRN foci and gammaH2AX returned to a control level, suggesting that cells adapted to hypertonicity by repairing DNA. We conclude that cells respond normally to DSB and repair the DNA damages induced by hypertonicity.
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Affiliation(s)
- Mee Rie Sheen
- Division of Nephrology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Bryson SP, Joyce EM, Martell DJ, Lee LEJ, Holt SE, Kales SC, Fujiki K, Dixon B, Bols NC. A cell line (HEW) from embryos of haddock (Melanogrammus aeglefinius) and its capacity to tolerate environmental extremes. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2006; 8:641-53. [PMID: 16909215 DOI: 10.1007/s10126-005-6163-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2005] [Accepted: 05/08/2006] [Indexed: 05/11/2023]
Abstract
Cell lines can be useful experimental tools for studying marine fish, which are often difficult to routinely obtain and maintain in the laboratory. As few cell lines are available from coldwater marine fish, cultures were initiated from late gastrula embryos of haddock (Melanogrammus aeglefinus) in Leibovitz's L-15 with fetal bovine serum (FBS). From one culture, a cell line (HEW) emerged that has been grown for close to 100 population doublings, was heteroploid, and expressed telomerase activity, all of which suggest HEW is immortal. Growth occurred only if FBS was present and was optimal at 12 to 18 degrees C. Usually most cells had an epithelial-like morphology, but under some conditions, cells drew up into round central bodies from which radiated cytoplasmic extensions with multiple branches. These neural-like cells appeared within a few hours of cultures being placed at 28 degrees C or being switch to a simple salt solution (SSS). At 28 degrees C, cells died within 24 h. In SSS, HEW cells survived as a monolayer for at least 7 days. The sensitivity of HEW cells to morphological change and their capacity to withstand starvation should make them useful for investigating cellular responses to environmental stresses.
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Affiliation(s)
- Steve P Bryson
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
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Stookey JD, Barclay D, Arieff A, Popkin BM. The altered fluid distribution in obesity may reflect plasma hypertonicity. Eur J Clin Nutr 2006; 61:190-9. [PMID: 17021599 DOI: 10.1038/sj.ejcn.1602521] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE This study explored whether the increased extracellular relative to intracellular fluid (ECF/ICF) ratio in obesity might reflect osmotic effects of elevated plasma solute concentrations. DESIGN Cross-sectional, epidemiological survey. SETTING AND SUBJECTS The present analysis used nationally representative data from the Third National Health and Nutrition Examination Survey on community-dwelling adults (aged 40-59 years) in the US without evidence of glucose dysregulation or chronic disease (n=1285). INTERVENTION Body mass index (BMI) was estimated from measured height and weight. Total body reactance, an index of body fluid distribution, was determined by bioelectrical impedance analysis. Plasma tonicity (the cumulative index of osmotically effective plasma solute) was estimated from plasma glucose, sodium and potassium. Sex-specific relative odds of lower reactance (<or=50 Omega/m for women, <or=40 Omega/m for men) and plasma hypertonicity (tonicity >or=295 mmol/l) associated with overweight (25<or=BMI <30) and obesity (BMI>or=30) were estimated using logistic regression models that controlled for sociodemographic variables, smoking, leisure-time physical activity, total energy intake, serum creatinine, plasma insulin and glucose. Multinomial logistic regression models tested for associations between weight status and specific serum solute. RESULTS Independent of covariates, in men and women, overweight and obesity were associated with increased odds of lower reactance and hypertonicity. Overweight and obese individuals with lower reactance had significantly higher serum sodium than normal weight individuals. CONCLUSIONS Elevated plasma solute concentrations are associated with obesity in free-living adults. Physicians and researchers should be alert to a possible link between hypertonicity and obesity. SPONSORSHIP Grants from the NIH, Nestle Waters.
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Affiliation(s)
- J D Stookey
- Children's Hospital of Oakland Research Institute, Oakland, CA 94609, USA.
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