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Abstract
Dynamic remodeling of the actin cytoskeleton is an essential feature for virtually all actin-dependent cellular processes, including cell migration, cell cycle progression, chromatin remodeling and gene expression, and even the DNA damage response. An altered actin cytoskeleton is a structural hallmark associated with numerous pathologies ranging from cardiovascular diseases to immune disorders, neurological diseases and cancer. The actin cytoskeleton in cells is regulated through the orchestrated actions of a myriad of actin-binding proteins. In this Review, we provide a brief overview of the structure and functions of the actin-monomer-binding protein profilin-1 (Pfn1) and then discuss how dysregulated expression of Pfn1 contributes to diseases associated with the cardiovascular system.
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Affiliation(s)
| | - David Gau
- Bioengineering, University of Pittsburgh
| | - Partha Roy
- Bioengineering, University of Pittsburgh.,Pathology, University of Pittsburgh, 306 Center for Bioengineering, University of Pittsburgh, 300 Technology Drive, Pittsburgh, PA 15219, USA
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Domanski D, Zegrocka-Stendel O, Perzanowska A, Dutkiewicz M, Kowalewska M, Grabowska I, Maciejko D, Fogtman A, Dadlez M, Koziak K. Molecular Mechanism for Cellular Response to β-Escin and Its Therapeutic Implications. PLoS One 2016; 11:e0164365. [PMID: 27727329 PMCID: PMC5058498 DOI: 10.1371/journal.pone.0164365] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 09/23/2016] [Indexed: 11/18/2022] Open
Abstract
β-escin is a mixture of triterpene saponins isolated from the horse chestnut seeds (Aesculus hippocastanum L.). The anti-edematous, anti-inflammatory and venotonic properties of β-escin have been the most extensively clinically investigated effects of this plant-based drug and randomized controlled trials have proved the efficacy of β-escin for the treatment of chronic venous insufficiency. However, despite the clinical recognition of the drug its pharmacological mechanism of action still remains largely elusive. To determine the cellular and molecular basis for the therapeutic effectiveness of β-escin we performed discovery and targeted proteomic analyses and in vitro evaluation of cellular and molecular responses in human endothelial cells under inflammatory conditions. Our results demonstrate that in endothelial cells β-escin potently induces cholesterol synthesis which is rapidly followed with marked fall in actin cytoskeleton integrity. The concomitant changes in cell functioning result in a significantly diminished responses to TNF-α stimulation. These include reduced migration, alleviated endothelial monolayer permeability, and inhibition of NFκB signal transduction leading to down-expression of TNF-α-induced effector proteins. Moreover, the study provides evidence for novel therapeutic potential of β-escin beyond the current vascular indications.
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Affiliation(s)
- Dominik Domanski
- Laboratory of Mass Spectrometry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Oliwia Zegrocka-Stendel
- Centre for Preclinical Research and Technology, Department of Immunology, Biochemistry and Nutrition, Medical University of Warsaw, Warsaw, Poland
| | - Anna Perzanowska
- Laboratory of Mass Spectrometry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Malgorzata Dutkiewicz
- Centre for Preclinical Research and Technology, Department of Immunology, Biochemistry and Nutrition, Medical University of Warsaw, Warsaw, Poland
| | - Magdalena Kowalewska
- Department of Molecular and Translational Oncology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
| | - Iwona Grabowska
- Department of Cytology, Faculty of Biology, University of Warsaw, Warsaw, Miecznikowa 1, 02–096 Warsaw, Poland
| | - Dorota Maciejko
- Centre for Preclinical Research and Technology, Department of Immunology, Biochemistry and Nutrition, Medical University of Warsaw, Warsaw, Poland
| | - Anna Fogtman
- Laboratory for Microarray Analysis CORELAB, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Michal Dadlez
- Laboratory of Mass Spectrometry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Koziak
- Centre for Preclinical Research and Technology, Department of Immunology, Biochemistry and Nutrition, Medical University of Warsaw, Warsaw, Poland
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Tamplenizza M, Lenardi C, Maffioli E, Nonnis S, Negri A, Forti S, Sogne E, De Astis S, Matteoli M, Schulte C, Milani P, Tedeschi G. Nitric oxide synthase mediates PC12 differentiation induced by the surface topography of nanostructured TiO2. J Nanobiotechnology 2013; 11:35. [PMID: 24119372 PMCID: PMC3815074 DOI: 10.1186/1477-3155-11-35] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 09/02/2013] [Indexed: 12/12/2022] Open
Abstract
Background Substrate nanoscale topography influences cell proliferation and differentiation through mechanisms that are at present poorly understood. In particular the molecular mechanism through which cells 'sense’ and adapt to the substrate and activate specific intracellular signals, influencing cells survival and behavior, remains to be clarified. Results To characterize these processes at the molecular level we studied the differentiation of PC12 cells on nanostructured TiO2 films obtained by supersonic cluster beam deposition. Our findings indicate that, in PC12 cells grown without Nerve Growth Factor (NGF), the roughness of nanostructured TiO2 triggers neuritogenesis by activating the expression of nitric oxide synthase (NOS) and the phospho-extracellular signal-regulated kinase 1/2 (pERK1/2) signaling. Differentiation is associated with an increase in protein nitration as observed in PC12 cells grown on flat surfaces in the presence of NGF. We demonstrate that cell differentiation and protein nitration induced by topography are not specific for PC12 cells but can be regarded as generalized effects produced by the substrate on different neuronal-like cell types, as shown by growing the human neuroblastoma SH-SY5Y cell line on nanostructured TiO2. Conclusion Our data provide the evidence that the nitric oxide (NO) signal cascade is involved in the differentiation process induced by nanotopography, adding new information on the mechanism and proteins involved in the neuritogenesis triggered by the surface properties.
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Affiliation(s)
- Margherita Tamplenizza
- CIMAINA and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, Milano 20133, Italy.
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Moro CF, Consonni SR, Rosa RG, Nascimento MAC, Joazeiro PP. High iNOS mRNA and protein localization during late pregnancy suggest a role for nitric oxide in mouse pubic symphysis relaxation. Mol Reprod Dev 2012; 79:272-82. [PMID: 22223460 DOI: 10.1002/mrd.22020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 12/13/2011] [Indexed: 11/10/2022]
Abstract
Remodeling and relaxation of the mouse pubic symphysis (PS) are central events in parturition. The mouse PS remodels in a hormone-controlled process that involves the modification of the fibrocartilage into an interpubic ligament (IpL), followed by its relaxation prior to parturition. It is recognized that nitric oxide synthase (NOS) and consequently nitric oxide (NO) generation play important roles in extracellular matrix modification, and may promote cytoskeleton changes that contribute to the remodeling of connective tissue, which precedes the onset of labor. To our knowledge, no studies thus far have investigated inducible nitric oxide synthase (iNOS) expression, protein localization, and NO generation in the mouse PS during pregnancy. In this work, we used a combination of the immunolocalization of iNOS, its relative mRNA expression, and NO production to examine the possible involvement of iNOS in remodeling and relaxation of the mouse IpL during late pregnancy. The presence of iNOS was observed in chondrocytes and fibroblast-like cells in the interpubic tissues. In addition, iNOS mRNA and NO production were higher during preterm labor on Day 19 of pregnancy (D19) than NO production on D18 or in virgin groups. The significant increase in iNOS mRNA expression and NO generation from the partially relaxed IpL at D18 to the completely relaxed IpL at D19 may indicate that NO plays an important role in late pregnancy during relaxation of the mouse IpL.
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Affiliation(s)
- Camila Fernandes Moro
- Department of Histology and Embryology, State University of Campinas (Unicamp), Campinas, SP, Brazil
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Siamwala JH, Reddy SH, Majumder S, Kolluru GK, Muley A, Sinha S, Chatterjee S. Simulated microgravity perturbs actin polymerization to promote nitric oxide-associated migration in human immortalized Eahy926 cells. PROTOPLASMA 2010; 242:3-12. [PMID: 20174953 DOI: 10.1007/s00709-010-0114-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 01/18/2010] [Indexed: 05/28/2023]
Abstract
Microgravity causes endothelium dysfunctions and vascular endothelium remodeling in astronauts returning from space flight. Cardiovascular deconditioning occurs as a consequence of an adaptive response to microgravity partially due to the effects exerted at cellular level. Directional migration of endothelial cell which are central in maintaining the structural integrity of vascular walls is regulated by chemotactic, haptotactic, and mechanotactic stimuli which are essential for vasculogenesis. We explored the migration property of transformed endothelial cells (EC) exposed to 2-h microgravity, simulated using a three-dimensional clinostat constructed based on blueprint published by the Fokker Space, Netherlands. Migration of EC was measured using the scrap wound healing in the presence or absence of actin polymerization inhibitor-cytochalasin D (CD) in Eahy926 cell lines. Simulated microgravity increased cellular migration by 25% while CD-blocked microgravity induced cellular migration. The key migratory structures of cells, filopodia and lamellipodia, formed by EC were more in simulated microgravity compared to gravity. Parallel experiments with phalloidin and diaminorhodamine-4M (DAR-4M) showed that simulated microgravity caused actin rearrangements that lead to 25% increase in nitric oxide production. Further nitric oxide measurements showed a higher nitric oxide production which was not abrogated by phosphoinositol 3 kinase inhibitor (Wortmanin). Bradykinin, an inducer of nitric oxide, prompted two folds higher nitric oxide production along with simulated microgravity in a synergistic manner. We suggest that limited exposure to simulated microgravity increases Eahy926 cell migration by modulating actin and releasing nitric oxide.
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Affiliation(s)
- Jamila H Siamwala
- Vascular Biology Lab, AU-KBC Research Centre, Anna University, MIT Campus, Chromepet, Chennai, 600044, India
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Herman AP, Tomaszewska-Zaremba D. Effect of endotoxin on the expression of GnRH and GnRHR genes in the hypothalamus and anterior pituitary gland of anestrous ewes. Anim Reprod Sci 2010; 120:105-11. [PMID: 20427135 DOI: 10.1016/j.anireprosci.2010.03.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 02/26/2010] [Accepted: 03/31/2010] [Indexed: 11/18/2022]
Abstract
An immune/inflammatory challenge can affect reproduction at the level of the hypothalamus, pituitary gland, or gonads. Nonetheless, the major impact is thought to occur within the brain or the pituitary gland. The present study was designed to examine the effect of intravenous (i.v.) lipopolysaccharide (LPS) injection on the expression of gonadotropin-releasing hormone (GnRH) and the gonadotropin-releasing hormone receptor (GnRHR) genes in the hypothalamic structures where GnRH neurons are located as well as in the anterior pituitary gland (AP) of anestrous ewes. We also determined the effect of LPS on luteinizing hormone (LH) release. It was found that i.v. LPS injection significantly decreased GnRH and GnRHR mRNAs levels in the preoptic area (40%, p<or=0.05 and 60%, p<or=0.01 respectively) and median eminence (50% and 50% respectively; p<or=0.01). Endotoxin injection decreased plasma LH concentration (25%; p<or=0.05) and GnRHR gene expression (80%, p<or=0.01) in the AP. Together, these observations indicate that inflammatory challenge can affect the reproductive system at the hypothalamic level through modulation of the activity of GnRH-ergic neurons as well as at the level of the AP via inhibition of LH secretion or/and through reduction of the sensitivity of GnRH reactive pituitary cells to GnRH stimulation. The presence of GnRH mRNA in the median eminence, the hypothalamic structure where GnRH-ergic neurons' terminals are located, suggests that the axonal transport of GnRH mRNA may occur in these neurons. This phenomenon could play an important role in the physiology of GnRH neurons. Our data demonstrate that immune stress could be important inhibitor of this process.
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Affiliation(s)
- Andrzej Przemysław Herman
- Polish Academy of Sciences, The Kielanowski Institute of Animal Physiology and Nutrition, 05-110 Jabłonna, Poland.
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Src-mediated regulation of inflammatory responses by actin polymerization. Biochem Pharmacol 2010; 79:431-43. [DOI: 10.1016/j.bcp.2009.09.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 09/11/2009] [Accepted: 09/14/2009] [Indexed: 11/19/2022]
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Eswarappa SM, Pareek V, Chakravortty D. Role of actin cytoskeleton in LPS-induced NF-kappaB activation and nitric oxide production in murine macrophages. Innate Immun 2009; 14:309-18. [PMID: 18809655 DOI: 10.1177/1753425908096856] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Lipopolysaccharide (LPS) is a major cell wall component of Gram-negative bacteria and is known to cause actin cytoskeleton reorganization in a variety of cells including macrophages. Actin cytoskeleton dynamics influence many cell signaling pathways including the NF-kappaB pathway. LPS is also known to induce the expression of many pro-inflammatory genes via the NF-kappaB pathway. Here, we have investigated the role of actin cytoskeleton in LPS-induced NF-kappaB activation and signaling leading to the expression of iNOS and nitric oxide production. Using murine macrophages, we show that disruption of actin cytoskeleton by either cytochalasin D (CytD) or latrunculin B (LanB) does not affect LPS-induced NF-kappaB activation and the expression of iNOS, a NF-kappaB target gene. However, disruption of actin cytoskeleton caused significant reduction in LPS-induced nitric oxide production indicating a role of actin cytoskeleton in the post-translational regulation of iNOS.
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Affiliation(s)
- Sandeepa M Eswarappa
- Centre for Infectious Disease Research and Biosafety Laboratories, Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, Karnataka, India
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Higuchi C, Nakamura N, Yoshikawa H, Itoh K. Transient dynamic actin cytoskeletal change stimulates the osteoblastic differentiation. J Bone Miner Metab 2009; 27:158-67. [PMID: 19183835 DOI: 10.1007/s00774-009-0037-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Accepted: 07/11/2008] [Indexed: 11/26/2022]
Abstract
Dynamic cytoskeletal changes appear to be one of intracellular signals that control cell differentiation. To test this hypothesis, we examined the effects of short-term actin cytoskeletal changes on osteoblastic differentiation. We found an actin polymerization interfering reagent, cytochalasin D, promoted osteoblastic differentiation in mouse preosteoblastic MC3T3-E1 cells. We also found that these effects were mediated by the protein kinase D (PKD) pathway. Short-term cytochalasin D treatment increased alkaline phosphatase (ALP) activity, osteocalcin (OCN) secretion, and mineralization of the extracellular matrix in MC3T3-E1 cells, with temporary changes in actin cytoskeleton. Furthermore, the disruption of actin cytoskeleton induced phosphorylation of 744/748 serine within the activation loop of PKD in a dose-dependent manner. The protein kinase C (PKC)/PKD inhibitor Go6976 suppressed cytochalasin D-induced acceleration of osteoblastic differentiation, whereas Go6983, a specific inhibitor of conventional PKCs, did not. Involvement of PKD signaling was confirmed by using small interfering RNA to knock down PKD. In addition, another actin polymerization interfering reagent, latrunculin B, also stimulated ALP activity and OCN secretion with PKD activation. On the other hand, the present data suggested that transient dynamic actin cytoskeletal reorganization could be a novel cellular signal that directly stimulated osteoblastic differentiation.
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Affiliation(s)
- Chikahisa Higuchi
- Department of Orthopedic Surgery, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Kettenhofen N, Broniowska K, Keszler A, Zhang Y, Hogg N. Proteomic methods for analysis of S-nitrosation. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 851:152-9. [PMID: 17360249 PMCID: PMC1997299 DOI: 10.1016/j.jchromb.2007.02.035] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2006] [Revised: 02/01/2007] [Accepted: 02/05/2007] [Indexed: 02/07/2023]
Abstract
This review discusses proteomic methods to detect and identify S-nitrosated proteins. Protein S-nitrosation, the post-translational modification of thiol residues to form S-nitrosothiols, has been suggested to be a mechanism of cellular redox signaling by which nitric oxide can alter cellular function through modification of protein thiol residues. It has become apparent that methods that will detect and identify low levels of S-nitrosated protein in complex protein mixtures are required in order to fully appreciate the range, extent and selectivity of this modification in both physiological and pathological conditions. While many advances have been made in the detection of either total cellular S-nitrosation or individual S-nitrosothiols, proteomic methods for the detection of S-nitrosation are in relative infancy. This review will discuss the major methods that have been used for the proteomic analysis of protein S-nitrosation and discuss the pros and cons of this methodology.
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Affiliation(s)
- Nicholas Kettenhofen
- Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin. Milwaukee WI 53226
| | - Katarzyna Broniowska
- Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin. Milwaukee WI 53226
| | - Agnes Keszler
- Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin. Milwaukee WI 53226
| | - Yanhong Zhang
- Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin. Milwaukee WI 53226
| | - Neil Hogg
- Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin. Milwaukee WI 53226
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Broniowska KA, Zhang Y, Hogg N. Requirement of transmembrane transport for S-nitrosocysteine-dependent modification of intracellular thiols. J Biol Chem 2006; 281:33835-41. [PMID: 16893892 PMCID: PMC1839924 DOI: 10.1074/jbc.m603248200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
S-nitrosothiols have been implicated as intermediary transducers of nitric oxide bioactivity; however, the mechanisms by which these compounds affect cellular functions have not been fully established. In this study, we have examined the effect of S-nitrosothiol transport on intracellular thiol status and upon the activity of a target protein (caspase-3), in bovine aortic endothelial cells. We have previously demonstrated that the specific transport of amino acid-based S-nitrosothiols (S-nitroso-L-cysteine and S-nitrosohomocysteine) occurs via amino acid transport system L to generate high levels of intracellular protein S-nitrosothiols (Zhang, Y., and Hogg, N. (2004) Proc. Natl. Acad. Sci. U. S. A. 101, 7891-7896). In this study, we demonstrate that the transport of S-nitrosothiols is essential for these compounds to affect intracellular thiol levels and to modify intracellular protein activity. Importantly, the ability of these compounds to affect intracellular processes occurs independently of nitric oxide formation. These findings suggest that the major action of these compounds is not to liberate nitric oxide in the extracellular space but to be specifically transported into cells where they are able to modify cellular functions through nitric oxide-independent mechanisms.
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Affiliation(s)
- Katarzyna A. Broniowska
- From the Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Yanhong Zhang
- From the Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Neil Hogg
- From the Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
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Genescà M, Sola A, Hotter G. Actin cytoskeleton derangement induces apoptosis in renal ischemia/reperfusion. Apoptosis 2006; 11:563-71. [PMID: 16528472 DOI: 10.1007/s10495-006-4937-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
UNLABELLED This study evaluated whether cytoskeletal alterations during the ischemic conditions associated with kidney preservation could determine apoptosis. Cytoskeletal alterations are among the main effects of ischemia and may induce apoptosis. Rat kidneys were preserved in University of Wisconsin (UW) solution for 24 h. Some groups of animals underwent 45 min of warm ischemia (WI) to evaluate its effect on both the actin cytoskeleton and apoptosis (assessed by caspase-3 activity and TUNEL staining). Swinholide A (SwinA) and Latrunculin B (LB), two actin cytoskeleton-targeted agents, were administered to assess the effect of direct actin disruption on apoptosis. Jasplakinolide (JP), a compound that stabilizes actin filaments, was administered to evaluate the effect of actin stabilization. Apoptosis was evaluated at 3 h of ex vivo reperfusion using the isolated perfused rat kidney (IPK) model. RESULTS Apoptosis increased during reperfusion with WI or administration of actin disruptor agents. Administration of stabilizing agents reversed apoptosis in kidneys that had previously undergone WI or had received an actin disruptor agent. CONCLUSION The disruption of the actin cytoskeleton during ischemic conditions associated with kidney preservation induces apoptosis upon reperfusion through caspase-3 activation.
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Affiliation(s)
- M Genescà
- Department of Experimental Pathology, IIBB-CSIC, IDIBAPS, Barcelona, Spain
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Abstract
The capacity of cells to maintain homeostasis during oxidative stress resides in activation or induction of protective enzymes. Nuclear-factor-E2-related factor (Nrf)-2 as a member of bZIP transcription factors is expressed in a variety of tissues. Transcriptional activation of antioxidant genes through an antioxidant response element (ARE) is largely dependent upon Nrf2. The genes that contain a functional ARE include those encoding GSTA1, GSTA2, NAD(P)H:quinone reductase, and gamma-glutamylcysteine synthetase heavy and light subunits that play a role in defense against oxidative stress. Previously, we showed that phosphatidylinositol 3-kinase (PI3-kinase) controls nuclear translocation of Nrf2 in response to oxidative stress, which involves rearrangement of actin microfilaments. Now, we report that PI3-kinase is responsible for the rise of cellular Ca(2+), which is requisite for nuclear translocation of Nrf2. Immunocytochemistry and subcellular fractionation analyses revealed that Nrf2 relocated from the cytoplasm to the plasma membrane prior to its nuclear translocation. We further found that CCAAT/enhancer binding protein-beta (C/EBPbeta), peroxisome proliferatoractivated receptor-gamma (PPARgamma), and retinoid X receptor (RXR) heterodimer serve as the activating transcription factors for the phase II gene induction. Hence, PI3-kinase-mediated Nrf2 activation in combination with activating PPARgamma-RXR and C/EBPbeta contributes to antioxidant phase II enzyme induction via coordinate gene transactivation.
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Affiliation(s)
- Keon Wook Kang
- National Research Laboratory, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, South Korea
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Cybulsky AV, Takano T, Papillon J, Bijian K, Guillemette J. Activation of the extracellular signal-regulated kinase by complement C5b-9. Am J Physiol Renal Physiol 2005; 289:F593-603. [PMID: 15855657 DOI: 10.1152/ajprenal.00066.2005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Extracellular signals may be transmitted to nuclear or cytoplasmic effectors via the mitogen-activated protein kinases. In the passive Heymann nephritis (PHN) model of membranous nephropathy, complement C5b-9 induces glomerular epithelial cell (GEC) injury, proteinuria, and activation of phospholipases and protein kinases. This study addresses the complement-mediated activation of the extracellular signal-regulated kinase (ERK). C5b-9 induced ERK threonine202/tyrosine204 phosphorylation (which correlates with activation) in GEC in culture and PHN in vivo. Expression of a dominant-inhibitory mutant of Ras reduced complement-mediated activation of ERK, but activation was not affected significantly by downregulation of protein kinase C. Complement-induced ERK activation resulted in phosphorylation of cytosolic phospholipase A2 and was, in part, responsible for phosphorylation of mitogen-activated protein kinase-associated protein kinase-2, but did not induce phosphorylation of the transcription factor, Elk-1. Activation of ERK was attenuated by drugs that disassemble the actin cytoskeleton (cytochalasin D, latrunculin B), and these compounds interfered with the activation of ERK by mitogen-activated protein kinase kinase (MEK). Overexpression of a constitutively active RhoA as well as inhibition of Rho-associated kinase blocked complement-mediated ERK activation. Complement cytotoxicity was enhanced after disassembly of the actin cytoskeleton but was unaffected after inhibition of complement-induced ERK activation. However, complement cytotoxicity was enhanced in GEC that stably express constitutively active MEK. Thus complement-induced ERK activation depends on cytoskeletal remodelling and affects the regulation of distinct downstream substrates, while chronic, constitutive ERK activation exacerbates complement-mediated GEC injury.
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Affiliation(s)
- Andrey V Cybulsky
- Department of Medicine, McGill University Health Centre, McGill University, Montreal, Quebec, Canada.
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Banas B, Wörnle M, Merkle M, Gonzalez-Rubio M, Schmid H, Kretzler M, Pietrzyk MC, Fink M, Perez de Lema G, Schlöndorff D. Binding of the chemokine SLC/CCL21 to its receptor CCR7 increases adhesive properties of human mesangial cells. Kidney Int 2005; 66:2256-63. [PMID: 15569314 DOI: 10.1111/j.1523-1755.2004.66037.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Adherence of human mesangial cells to the surrounding matrix contributes to glomerular homeostasis and is important for the maintenance of glomerular architecture and function in normal adult human kidney. The expression of chemokines and corresponding chemokine receptors on adjacent intrinsic renal cells indicates a novel chemokine/chemokine receptor function on nonimmune cells important for glomerular homeostasis. A constitutive expression of the chemokine SLC/CCL21 on human podocytes and of its corresponding receptor CCR7 on mesangial cells was shown before. SLC/CCL21 has a positive effect on proliferation and migration of mesangial cells and leads to increased cell survival in Fas-induced apoptosis. In leukocytes chemokines mediate integrin-dependent firm adhesion. Therefore, we examined the influence of chemokine receptor CCR7 activation by SLC/CCL21 on adhesive properties of human mesangial cells to matrix molecules. METHODS Adhesion assays, mechanical detachment assays, and evaluation of integrin activation by integrin-linked kinase activity were performed. Changes in the cytoskeletal F-actin were illustrated by phalloidin immunofluorescence staining. RESULTS SLC/CCL21 stimulation enhanced adhesiveness to fibronectin in a time- and concentration-dependent manner. SLC/CCL21 also increased the firmness of mesangial cells adhesion as judged by detachment assays. Furthermore activation of integrin-linked kinase occurred with SLC/CCL21 addition to mesangial cells, resulting in increased phosphorylation of glycogen synthase kinase-3 (GSK-3) and protein kinase B (PKB/Akt). Exposure of mesangial cells to SLC/CCL21 also resulted in F-actin rearrangements with membrane ruffling and extensions leading to bridging between mesangial cells. CONCLUSION Activation of CCR7 on mesangial cells by SLC/CCL21 enhances the degree and firmness of cell adhesion and increases cell spreading and the formation of cell-cell contacts. This includes integrin-linked kinase activation and F-actin rearrangements. Thus, local chemokine generation and chemokine receptor expression on mesangial cells may play an important role in the maintenance of glomerular homeostasis and in local remodeling processes.
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Affiliation(s)
- Bernhard Banas
- Nephrologisches Zentrum, Medizinische Poliklinik, Ludwig-Maximilians-Universität München, Germany.
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Petry C, Fritz G, Pfeilschifter J, Huwiler A. Inhibition of Rho modulates cytokine-induced prostaglandin E2 formation in renal mesangial cells. Biochim Biophys Acta Mol Cell Biol Lipids 2004; 1636:108-18. [PMID: 15164758 DOI: 10.1016/j.bbalip.2003.11.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2003] [Accepted: 11/20/2003] [Indexed: 12/21/2022]
Abstract
Stimulation of rat mesangial cells for 24 h with interleukin-1beta (IL- 1beta) plus forskolin (Fk) leads to a marked increase in prostaglandin E2 (PGE2) synthesis. This effect is further enhanced by the small G-protein Rho inhibitor toxin A. A similar increase in PGE2 formation is obtained with Y27632, a Rho-dependent kinase inhibitor, and with lovastatin, a hydroxymethylglutaryl-coenzyme A inhibitor which depletes cells from geranylgeranyl moieties and thus blocks Rho activation. In parallel to the increased PGE2 synthesis, a potentiation of IL-1beta-induced secretory group IIA phospholipases A2 (sPLA2-IIA) protein expression also occurs by Rho inhibition. However, only toxin A triggers an increased sPLA2-IIA activity consistent with the elevated levels of protein expression, whereas Y27632 and lovastatin rather reduced IL-1beta-induced sPLA2-IIA activity. In vitro activity studies reveal that Y27632 and lovastatin can directly block sPLA2-IIA enzyme activity in a concentration-dependent manner. Interestingly, in the absence of IL-1beta/Fk stimulation and the lack of sPLA2-IIA protein expression, all Rho inhibitors exert a small but significant increase in PGE2 formation suggesting that additional PLA2s or downstream enzymes like cyclooxygenases or prostaglandin synthases may be activated by Rho inhibitors. Western blot analyses of toxin A-, Y27632- and lovastatin-stimulated cells reveal that the cytosolic group IV PLA2 (cPLA2) and the cytosolic PGE2 synthase (cPGES), but not the sPLA2-IIA, cyclooxygenase-2 or the microsomal PGE2 synthase (mPGES), are upregulated compared to unstimulated cells. Furthermore, the Rho inhibitors induced arachidonic acid release from intact cells which is blocked by the cPLA2 inhibitor methyl arachidonyl fluorophosphonate (MAFP). In summary, these data show that inhibition of the small G-protein Rho, either by toxin A, lovastatin, or Y27632, exert a dual effect on mesangial cells: (i) in the absence of an inflammatory stimulus it activates the constitutive cPLA2 and cPGE2 synthase and generates low amount of PGE2. (ii) In the presence of inflammatory cytokines it potentiates sPLA2-IIA expression and subsequent PGE2 formation. In addition, we identified lovastatin and Y27632 as direct inhibitors of sPLA2-IIA in a cell-free system.
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Affiliation(s)
- Claudia Petry
- Pharmazentrum Frankfurt, Klinikum der Johann Wolfgang Goethe-Universität, Theodor-Stern-Kai 7, D-60590, Frankfurt am Main, Germany
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18
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Hattori Y, Kasai K. Disruption of the Actin Cytoskeleton Up-Regulates iNOS Expression in Vascular Smooth Muscle Cells. J Cardiovasc Pharmacol 2004; 43:209-13. [PMID: 14716207 DOI: 10.1097/00005344-200402000-00007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Cytokines and bacterial lipopolysaccharide (LPS) induce the expression of inducible nitric oxide synthase (iNOS), resulting in the release of nitric oxide (NO) from vascular smooth muscle cells. We here demonstrated that disruption of F-actin formation by sequestration of G-actin with the toxin latrunculin B (Lat B) dramatically potentiated LPS-induced iNOS mRNA and protein expression. We also showed that Lat B enhanced interleukin-1beta- andbgr;- and TNFalpha-induced NO production. Lat B by itself had little or no effect on iNOS expression. Cytochalasin D also enhanced LPS-induced NO production. Lat B dose-dependently enhanced LPS-induced iNOS promoter activity but had no effect on the stability of iNOS mRNA. Staining of F-actin with nitrobenzoxadiazole (NBD)-phallacidin demonstrated that Lat B significantly impaired F-actin stress fiber formation. These data indicate that disruption of the actin cytoskeleton up-regulates cytokine-induced iNOS expression via transcriptional regulation. Further analysis of the signaling pathway from the actin cytoskeleton to iNOS expression may yield new insight into the mechanism of iNOS regulation.
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Affiliation(s)
- Yoshiyuki Hattori
- Department of Endocrinology & Metabolism, Dokkyo University School of Medicine, Mibu, Tochigi, Japan.
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19
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Yamaguchi M, Abiko Y, Nishimura M, Saitoh M, Kaku T. An Immunohistochemical Study of the Localization of Inducible Nitric Oxide Synthase (iNOS) and Heat Shock Protein (HSP) in Pleomorphic Adenoma. Acta Histochem Cytochem 2004. [DOI: 10.1267/ahc.37.267] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Masaru Yamaguchi
- Department of Oral Pathology, School of Dentistry, Health Sciences University of Hokkaido
| | - Yoshihiro Abiko
- Department of Oral Pathology, School of Dentistry, Health Sciences University of Hokkaido
| | - Michiko Nishimura
- Department of Oral Pathology, School of Dentistry, Health Sciences University of Hokkaido
| | - Masato Saitoh
- Department of Pediatric Dentistry, Health Sciences University of Hokkaido
| | - Tohru Kaku
- Department of Oral Pathology, School of Dentistry, Health Sciences University of Hokkaido
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20
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Johansson R, Persson K. Phenotypic modulation of cultured bladder smooth muscle cells and the expression of inducible nitric oxide synthase. Am J Physiol Regul Integr Comp Physiol 2003; 286:R642-8. [PMID: 14656765 DOI: 10.1152/ajpregu.00443.2003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phenotypic modulation of smooth muscle is associated with various pathological conditions, including bladder dysfunction. Cytoskeletal dynamics modulate the cell phenotype and were recently shown to be involved in regulation of inducible nitric oxide synthase (iNOS). We tested the hypothesis that the cell differentiation status affects iNOS expression, and that iNOS is preferentially expressed in immature dedifferentiated bladder smooth muscle cells (BSMC). Isolated at BSMC were put into different stages of differentiation by serum deprivation on laminin-coated plates in the presence of IGF-I and by interaction with Rho signaling and actin polymerization. iNOS and smooth muscle-myosin heavy chain (SM-MHC) protein expression were investigated with Western blot analysis. Our results showed iNOS protein in BSMC exposed to interleukin-1 beta (2 ng/ml) + TNF-alpha (50 ng/ml). Growth of BSMC in serum-free medium on laminin in the presence of IGF-I increased SM-MHC expression, whereas cytokine-induced iNOS was inhibited. Disruption of F-actin with latrunculin B (0.5 microM) potentiated iNOS expression and decreased SM-MHC expression. Rho inhibition with C3 (2.5 microg/ml) increased iNOS expression, whereas SM-MHC expression was slightly decreased. Rho-kinase inhibition with Y-27632 (10 microM) mediated a decrease in iNOS and a slight increase in SM-MHC expression. In conclusion, the capacity of BSMC to express iNOS was negatively correlated to differentiation status measured as SM-MHC expression. Actin cytoskeletal dynamics and Rho signaling are involved in regulation of cytokine-induced iNOS expression in BSMC. Phenotypic changes and impairment in actin cytoskeleton formation may potentiate cytokine activation and in turn increase nitric oxide production in the bladder during disease.
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Affiliation(s)
- Rebecka Johansson
- Department of Clinical and Experimental Pharmacology, Lund University Hospital, SE-221 85 Lund, Sweden. Rebecka.Johansson@klinfa m.lu.se
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21
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Cybulsky AV, Takano T, Papillon J, Khadir A, Bijian K, Le Berre L. The actin cytoskeleton facilitates complement-mediated activation of cytosolic phospholipase A2. Am J Physiol Renal Physiol 2003; 286:F466-76. [PMID: 14644750 DOI: 10.1152/ajprenal.00260.2003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cytosolic PLA(2)-alpha (cPLA(2)) and metabolites of arachidonic acid (AA) are key mediators of complement-dependent glomerular epithelial cell (GEC) injury. Assembly of C5b-9 increases cytosolic Ca(2+) concentration and results in transactivation of receptor tyrosine kinases and activation of PLC-gamma 1 and the 1,2-diacylglycerol (DAG)-PKC pathway. Ca(2+) and PKC are essential for membrane association and increased catalytic activity of cPLA(2). This study addresses the role of the actin cytoskeleton in cPLA(2) activation. Depolymerization of F-actin by cytochalasin D or latrunculin B reduced complement-dependent [(3)H]AA release, as well as the complement-induced increase in cPLA(2) activity. These effects were due to inhibition of [(3)H]DAG production and PKC activation, implying interference with PLC. Complement-dependent [(3)H]AA release was also reduced by jasplakinolide, a compound that stabilizes F-actin and organizes actin filaments at the cell periphery, and calyculin A, which induces condensation of actin filaments at the plasma membrane. The latter drugs did not affect [(3)H]DAG production, suggesting their inhibitory actions were downstream of PKC. Neither cytochalasin D, latrunculin B, nor calyculin A affected association of cPLA(2) with microsomal membranes, and cytochalasin D and latrunculin B did not alter the localization of the endoplasmic reticulum. Stable transfection of constitutively active RhoA induced formation of stress fibers, stabilized F-actin, and attenuated the complement-induced increase in [(3)H]AA. Thus in GEC, cPLA(2) activation is dependent, in part, on actin remodeling. By regulating complement-mediated activation of cPLA(2), the actin cytoskeleton may contribute to the pathophysiology of GEC injury.
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Affiliation(s)
- Andrey V Cybulsky
- Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada H3A 1A1.
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22
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Daniliuc S, Bitterman H, Rahat MA, Kinarty A, Rosenzweig D, Lahat N, Nitza L. Hypoxia inactivates inducible nitric oxide synthase in mouse macrophages by disrupting its interaction with alpha-actinin 4. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:3225-32. [PMID: 12960352 DOI: 10.4049/jimmunol.171.6.3225] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Nitric oxide, produced in macrophages by the high output isoform inducible NO synthase (iNOS), is associated with cytotoxic effects and modulation of Th1 inflammatory/immune responses. Ischemia and reperfusion lead to generation of high NO levels that contribute to irreversible tissue damage. Ischemia and reperfusion, as well as their in vitro simulation by hypoxia and reoxygenation, induce the expression of iNOS in macrophages. However, the molecular regulation of iNOS expression and activity in hypoxia and reoxygenation has hardly been studied. We show in this study that IFN-gamma induced iNOS protein expression (by 50-fold from control, p < 0.01) and nitrite accumulation (71.6 +/- 14 micro M, p < 0.01 relative to control), and that hypoxia inhibited NO production (7.6 +/- 1.7 micro M, p < 0.01) without altering iNOS protein expression. Only prolonged reoxygenation restored NO production, thus ruling out the possibility that lack of oxygen, as a substrate, was the cause of hypoxia-induced iNOS inactivation. Hypoxia did not change the ratio between iNOS monomers and dimers, which are essential for iNOS activity, but the dimers were unable to produce NO, despite the exogenous addition of all cofactors and oxygen. Using immunoprecipitation, mass spectroscopy, and confocal microscopy, we demonstrated in normoxia, but not in hypoxia, an interaction between iNOS and alpha-actinin 4, an adapter protein that anchors enzymes to the actin cytoskeleton. Furthermore, hypoxia caused displacement of iNOS from the submembranal zones. We suggest that the intracellular localization and interactions of iNOS with the cytoskeleton are crucial for its activity, and that hypoxia inactivates iNOS by disrupting these interactions.
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Affiliation(s)
- Sharon Daniliuc
- Immunology Research Unit and Ischemia-Shock Research Laboratory, Carmel Medical Center, Rappaport Family Institute for Research in the Medical Sciences, and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
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23
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Witteck A, Yao Y, Fechir M, Förstermann U, Kleinert H. Rho protein-mediated changes in the structure of the actin cytoskeleton regulate human inducible NO synthase gene expression. Exp Cell Res 2003; 287:106-15. [PMID: 12799187 DOI: 10.1016/s0014-4827(03)00129-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Rho proteins (Rho, Rac, Cdc 42) are known to control the organization of the actin cytoskeleton as well as gene expression. Inhibition of Rho proteins by Clostridium difficile toxin B disrupted the F-actin cytoskeleton and enhanced cytokine-induced inducible nitric oxide synthase (iNOS) expression in human epithelial cells. Also specific inhibition by Y-27632 of p160ROCK, which mediates Rho effects on actin fibers, caused a disruption of the actin cytoskeleton and a superinduction of cytokine-induced iNOS expression. Accordingly, direct disruption of the actin cytoskeleton by cytochalasin D, latrunculin B, or jasplakinolide enhanced cytokine-induced iNOS expression. The transcription factor serum response factor (SRF) has been described as mediating actin cytoskeleton-dependent regulation of gene expression. Direct targets of SRF are activating protein 1 (AP1)-dependent genes. All compounds used inhibited SRF- and AP1-dependent reporter gene expression in DLD-1 cells. However, the enhancing effect of the actin cytoskeleton-disrupting compounds on human iNOS promoter activity was much less pronounced than the effect on iNOS mRNA expression. Therefore, besides transcriptional mechanisms, posttranscriptional effects seem to be involved in the regulation of iNOS expression by the above compounds. In conclusion, our data suggest that Rho protein-mediated changes of the actin cytoskeleton negatively modulate the expression of human iNOS.
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MESH Headings
- Actin Cytoskeleton/drug effects
- Actin Cytoskeleton/metabolism
- Bacterial Proteins
- Bacterial Toxins/pharmacology
- Bridged Bicyclo Compounds, Heterocyclic/pharmacology
- Cytochalasin D/pharmacology
- Cytokines/metabolism
- Cytokines/pharmacology
- Cytoskeleton/drug effects
- Cytoskeleton/metabolism
- Depsipeptides
- Enzyme Inhibitors/pharmacology
- Eukaryotic Cells/enzymology
- Gene Expression Regulation, Enzymologic/drug effects
- Gene Expression Regulation, Enzymologic/genetics
- Humans
- Intracellular Signaling Peptides and Proteins
- Nitric Oxide/metabolism
- Nitric Oxide Synthase/drug effects
- Nitric Oxide Synthase/genetics
- Nitric Oxide Synthase/metabolism
- Peptides, Cyclic/pharmacology
- Promoter Regions, Genetic/drug effects
- Promoter Regions, Genetic/genetics
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/metabolism
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Serum Response Factor/drug effects
- Serum Response Factor/genetics
- Serum Response Factor/metabolism
- Thiazoles/pharmacology
- Thiazolidines
- Transcription Factor AP-1/drug effects
- Transcription Factor AP-1/genetics
- Transcription Factor AP-1/metabolism
- Transcription, Genetic/drug effects
- Transcription, Genetic/genetics
- Tumor Cells, Cultured
- rho GTP-Binding Proteins/drug effects
- rho GTP-Binding Proteins/metabolism
- rho-Associated Kinases
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Affiliation(s)
- Andrea Witteck
- Department of Pharmacology, Johannes Gutenberg University, Obere Zahlbacher Strasse 67, D-55101, Mainz, Germany
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Shiu YT, Li S, Yuan S, Wang Y, Nguyen P, Chien S. Shear stress-induced c-fos activation is mediated by Rho in a calcium-dependent manner. Biochem Biophys Res Commun 2003; 303:548-55. [PMID: 12659853 DOI: 10.1016/s0006-291x(03)00388-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We aimed at elucidating the molecular basis of c-fos promoter activation in vascular endothelial cells (ECs) in response to shear stress, with emphases on Rho family GTPases (Rho, Cdc42, and Rac) and intracellular calcium. Dominant-negative and constitutively activated mutants of these GTPases were used to block the action of upstream signals and to activate the downstream pathways, respectively. The role of intracellular calcium was assessed with intracellular calcium chelators. Only Rho, but not Cdc42 or Rac, is involved in the shear stress induction of c-fos. This Rho-mediated shear-induction of c-fos is dependent on intracellular calcium, but not on the Rho effector p160ROCK or actin filaments. While the inhibition of p160ROCK and its ensuing disruption of actin filaments decreased the basal c-fos activity in static ECs (no flow), it did not affect the shear-inductive effect. The calcium chelator BAPTA-AM inhibits the shear-induction, as well as the static level, of c-fos activity.
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Affiliation(s)
- Yan-Ting Shiu
- Department of Bioengineering and the Whitaker Institute of Biomedical Engineering, University of California at San Diego, La Jolla, CA 92093-0427, USA
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25
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O'Reilly PJ, Hickman-Davis JM, Davis IC, Matalon S. Hyperoxia impairs antibacterial function of macrophages through effects on actin. Am J Respir Cell Mol Biol 2003; 28:443-50. [PMID: 12654633 DOI: 10.1165/rcmb.2002-0153oc] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Oxidative stress may impair alveolar macrophage function in patients with inflammatory lung diseases or those exposed to high concentrations of oxygen. We investigated putative mechanisms of injury to macrophages by oxidative stress, using RAW 264.7 cells exposed to 95% oxygen for 48 h. Hyperoxia-exposed macrophages were less able to phagocytose and kill Klebsiella pneumoniae than normoxic controls, despite increased production of nitric oxide, a free radical important in pathogen killing. Exposure of macrophages to hyperoxia had marked effects on the actin cytoskeleton, including increased actin polymerization, loss of cortical actin, formation of stress fibers, de novo synthesis of actin, and actin oxidation. Hyperoxia induced changes in cell morphology, with increased cell size and pseudopod formation. Exposure of macrophages to jasplakinolide, an agent that increases actin polymerization, also impaired their ability to phagocytose Klebsiella. Alveolar macrophages isolated from mice exposed to 100% oxygen for 84 h also demonstrated impaired phagocytic function, as well as similar effects on the actin cytoskeleton and cell morphology to macrophages exposed to hyperoxia in vitro. We conclude that oxidative stress in vitro and in vivo impairs macrophage antibacterial function through effects on actin.
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Affiliation(s)
- Philip J O'Reilly
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of Alabama at Birmingham, 35205-3703, USA
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26
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Kleinert H, Schwarz PM, Förstermann U. Regulation of the Expression of Inducible Nitric Oxide Synthase. Biol Chem 2003; 384:1343-64. [PMID: 14669979 DOI: 10.1515/bc.2003.152] [Citation(s) in RCA: 289] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Nitric oxide (NO), generated by the inducible isoform of nitric oxide synthase (iNOS), has been described to have beneficial microbicidal, antiviral, antiparasital, immunomodulatory, and antitumoral effects. However, aberrant iNOS induction at the wrong place or at the wrong time has detrimental consequences and seems to be involved in the pathophysiology of several human diseases. iNOS is primarily regulated at the expression level by transcriptional and post-transcriptional mechanisms. iNOS expression can be induced in many cell types with suitable agents such as bacterial lipopolysaccharides (LPS), cytokines, and other compounds. Pathways resulting in the induction of iNOS expression may vary in different cells or different species. Activation of the transcription factors NF-kappaB and STAT-1alpha, and thereby activation of the iNOS promoter, seems to be an essential step for iNOS induction in most cells. However, at least in the human system, also post-transcriptional mechanism are critically involved in the regulation of iNOS expression. The induction of iNOS can be inhibited by a wide variety of immunomodulatory compounds acting at the transcriptional levels and/or post-transcriptionally.
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Affiliation(s)
- Hartmut Kleinert
- Department of Pharmacology, Johannes Gutenberg University, D-55101 Mainz, Germany
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27
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Kang KW, Lee SJ, Park JW, Kim SG. Phosphatidylinositol 3-kinase regulates nuclear translocation of NF-E2-related factor 2 through actin rearrangement in response to oxidative stress. Mol Pharmacol 2002; 62:1001-10. [PMID: 12391262 DOI: 10.1124/mol.62.5.1001] [Citation(s) in RCA: 226] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Expression of phase II detoxifying genes is regulated by NF-E2-related factor 2 (Nrf2)-mediated antioxidant response element (ARE) activation. We showed previously that phosphatidylinositol 3 (PI3)-kinase plays an essential role in ARE-mediated rGSTA2 induction by oxidative stress. In view of the fact that the signaling pathway of PI3-kinase controls microfilaments and translocation of actin-associated proteins, the current study was designed to investigate the PI3-kinase-mediated nuclear translocation of Nrf2 and the interaction of Nrf2 with actin. tert-Butylhydroquinone (t-BHQ) caused Nrf2 to translocate into the nucleus in H4IIE cells, which was prevented by pretreatment of the cells with PI3-kinase inhibitors (wortmannin/LY294002). t-BHQ relocalized Nrf2 in concert with changes in actin microfilament architecture, as visualized by superposition of immunochemically stained Nrf2 and fluorescent phalloidin-stained actin. Furthermore, t-BHQ increased the level of nuclear actin, coimmunoprecipitated with Nrf2, which returned to that of control by pretreatment of the cells with PI3-kinase inhibitors. Cytochalasin B, an actin disruptor, alone stimulated actin-mediated nuclear translocation of Nrf2 and induced rGSTA2. In contrast, phalloidin, an agent that prevents actin filaments from depolymerization, inhibited Nrf2 translocation and rGSTA2 induction by t-BHQ. Subcellular fractionation and immunoblot analyses allowed us to detect both 57- and 100-kDa Nrf2. Immunoblot and immunoprecipitation assays showed that the 100-kDa protein comprised both Nrf2 and actin. The present study demonstrates that the PI3-kinase signaling pathway regulates rearrangement of actin microfilaments in response to oxidative stress and that depolymerization of actin causes a complex of Nrf2 bound with actin to translocate into nucleus.
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Affiliation(s)
- Keon Wook Kang
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Kwanak-gu, Seoul, South Korea
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28
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Liu R, Persson AE. Effects of nitric oxide on P2Y receptor resensitization in spontaneously hypertensive rat mesangial cells. J Hypertens 2002; 20:1835-42. [PMID: 12195127 DOI: 10.1097/00004872-200209000-00030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Cellular responses to agonists of G protein-coupled receptors are usually rapidly attenuated - a process known as 'receptor desensitization'. The mechanisms that attenuate signalling are important both physiologically and therapeutically. OBJECTIVE To evaluate the effects of nitric oxide on the P2Y receptor resensitization in cultured glomerular mesangial cells in spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) rats. METHODS The cytosolic calcium concentration ([Ca2+]i ) in cultured mesangial cells was determined with a fluorescence digital imaging system, using the intracellular fluorescent indicator, Fura 2-AM. RESULTS The first ATP-stimulated [Ca2+]i measured was significantly greater in SHRs (1330.25 +/- 360.31 nmol/l) than in WKY rats (974.28 +/- 397.72 nmol/l; 0.05). Spermine- -[4-[1-(3-aminopropyl)-2-hydroxy-2-nitrosohydrazino]-butyl-1,3-propanediamine (spermine NONOate) and L-arginine significantly increased the fourth ATP-stimulated [Ca2+]i in WKY rats ( P<0.01, 0.05, respectively). In SHRs, only spermine-NONOate was able to restore the fourth ATP-challenged [Ca2+]i value significantly. Nomega-nitro-L-arginine methyl ester (L-NAME) greatly reduced the second, third and fourth ATP-stimulated [Ca2+]i in WKY rats (P< 0.01), but not in SHRs. When the cells from WKY rats were superfused with L-NAME, L-arginine or spermine-NONOate for a period of 5 min before and during one single ATP challenge, the responses observed were not significantly different from those in controls. CONCLUSIONS L-Arginine and spermine-NONOate are able to increase P2Y receptor resensitization in rat mesangial cells, an effect that is less potent in SHRs than in WKY rats. The presence of >l-NAME enhanced receptor desensitization in WKY rats, but not in SHRs.
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Affiliation(s)
- Ruisheng Liu
- Department of Medical Cell Biology, Uppsala University, Sweden
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29
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Abstract
S-nitrosothiols are biological metabolites of nitric oxide. It has often been suggested that they represent a more stable metabolite of nitric oxide that can either be stored, or transported, although the evidence for this is sparse. There are many unanswered questions concerning how S-nitrosothiols are formed, how they are metabolized and how they elicit biological responses. These questions are highlighted by the fact that the known chemistry of nitric oxide, thiols, and S-nitrosothiols cannot serve to explain their proposed biological activities. This review attempts to highlight the gulf between our chemical understanding of S-nitrosothiols and the proposed biological activities of these compounds with respect to guanylyl cyclase-independent nitric oxide bioactivity and also the control of vascular tone.
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Affiliation(s)
- Neil Hogg
- Biophysics Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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