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Noom A, Sawitzki B, Knaus P, Duda GN. A two-way street - cellular metabolism and myofibroblast contraction. NPJ Regen Med 2024; 9:15. [PMID: 38570493 PMCID: PMC10991391 DOI: 10.1038/s41536-024-00359-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 03/20/2024] [Indexed: 04/05/2024] Open
Abstract
Tissue fibrosis is characterised by the high-energy consumption associated with myofibroblast contraction. Although myofibroblast contraction relies on ATP production, the role of cellular metabolism in myofibroblast contraction has not yet been elucidated. Studies have so far only focused on myofibroblast contraction regulators, such as integrin receptors, TGF-β and their shared transcription factor YAP/TAZ, in a fibroblast-myofibroblast transition setting. Additionally, the influence of the regulators on metabolism and vice versa have been described in this context. However, this has so far not yet been connected to myofibroblast contraction. This review focuses on the known and unknown of how cellular metabolism influences the processes leading to myofibroblast contraction and vice versa. We elucidate the signalling cascades responsible for myofibroblast contraction by looking at FMT regulators, mechanical cues, biochemical signalling, ECM properties and how they can influence and be influenced by cellular metabolism. By reviewing the existing knowledge on the link between cellular metabolism and the regulation of myofibroblast contraction, we aim to pinpoint gaps of knowledge and eventually help identify potential research targets to identify strategies that would allow switching tissue fibrosis towards tissue regeneration.
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Affiliation(s)
- Anne Noom
- Julius Wolff Institute (JWI), Berlin Institute of Health and Center for Musculoskeletal Surgery at Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
- BIH Center for Regenerative Therapies (BCRT), Berlin Institute of Health at Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Birgit Sawitzki
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt University of Berlin, 13353, Berlin, Germany
- Center of Immunomics, Berlin Institute of Health at Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Petra Knaus
- Institute of Chemistry and Biochemistry - Biochemistry, Freie Universität Berlin, 14195, Berlin, Germany
| | - Georg N Duda
- Julius Wolff Institute (JWI), Berlin Institute of Health and Center for Musculoskeletal Surgery at Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany.
- BIH Center for Regenerative Therapies (BCRT), Berlin Institute of Health at Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany.
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2
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Kohno T, Kojima T. Atypical Macropinocytosis Contributes to Malignant Progression: A Review of Recent Evidence in Endometrioid Endometrial Cancer Cells. Cancers (Basel) 2022; 14:cancers14205056. [PMID: 36291839 PMCID: PMC9599675 DOI: 10.3390/cancers14205056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/01/2022] [Accepted: 10/13/2022] [Indexed: 11/24/2022] Open
Abstract
Simple Summary A novel type of macropinocytosis has been identified as a trigger for the malignant progression of endometrial cancer. Transiently reducing epithelial barrier homeostasis leads to macropinocytosis by splitting between adjacent cells in endometrioid endometrial cancer. Macropinocytosis causes morphological changes in well-differentiated to poorly differentiated cancer cells. Inhibition of macropinocytosis promotes a persistent dormant state in the intrinsic KRAS-mutated cancer cell line Sawano. This review focuses on the mechanisms of atypical macropinocytosis and its effects on cellular function, and it describes the physiological processes involved in inducing resting conditions in endometrioid endometrial cancer cells. Abstract Macropinocytosis is an essential mechanism for the non-specific uptake of extracellular fluids and solutes. In recent years, additional functions have been identified in macropinocytosis, such as the intracellular introduction pathway of drugs, bacterial and viral infection pathways, and nutritional supplement pathway of cancer cells. However, little is known about the changes in cell function after macropinocytosis. Recently, it has been reported that macropinocytosis is essential for endometrial cancer cells to initiate malignant progression in a dormant state. Macropinocytosis is formed by a temporary split of adjacent bicellular junctions of epithelial sheets, rather than from the apical surface or basal membrane, as a result of the transient reduction of tight junction homeostasis. This novel type of macropinocytosis has been suggested to be associated with the malignant pathology of endometriosis and endometrioid endometrial carcinoma. This review outlines the induction of malignant progression of endometrial cancer cells by macropinocytosis based on a new mechanism and the potential preventive mechanism of its malignant progression.
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3
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Dekker Y, Le Dévédec SE, Danen EHJ, Liu Q. Crosstalk between Hypoxia and Extracellular Matrix in the Tumor Microenvironment in Breast Cancer. Genes (Basel) 2022; 13:genes13091585. [PMID: 36140753 PMCID: PMC9498429 DOI: 10.3390/genes13091585] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 08/28/2022] [Accepted: 08/31/2022] [Indexed: 11/24/2022] Open
Abstract
Even though breast cancer is the most diagnosed cancer among women, treatments are not always successful in preventing its progression. Recent studies suggest that hypoxia and the extracellular matrix (ECM) are important in altering cell metabolism and tumor metastasis. Therefore, the aim of this review is to study the crosstalk between hypoxia and the ECM and to assess their impact on breast cancer progression. The findings indicate that hypoxic signaling engages multiple mechanisms that directly contribute to ECM remodeling, ultimately increasing breast cancer aggressiveness. Second, hypoxia and the ECM cooperate to alter different aspects of cell metabolism. They mutually enhance aerobic glycolysis through upregulation of glucose transport, glycolytic enzymes, and by regulating intracellular pH. Both alter lipid and amino acid metabolism by stimulating lipid and amino acid uptake and synthesis, thereby providing the tumor with additional energy for growth and metastasis. Third, YAP/TAZ signaling is not merely regulated by the tumor microenvironment and cell metabolism, but it also regulates it primarily through its target c-Myc. Taken together, this review provides a better understanding of the crosstalk between hypoxia and the ECM in breast cancer. Additionally, it points to a role for the YAP/TAZ mechanotransduction pathway as an important link between hypoxia and the ECM in the tumor microenvironment, driving breast cancer progression.
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Affiliation(s)
- Yasmin Dekker
- Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, The Netherlands
| | - Sylvia E. Le Dévédec
- Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, The Netherlands
| | - Erik H. J. Danen
- Leiden Academic Centre for Drug Research, Leiden University, 2333 CC Leiden, The Netherlands
- Correspondence: (E.H.J.D.); (Q.L.)
| | - Qiuyu Liu
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing 100102, China
- Correspondence: (E.H.J.D.); (Q.L.)
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4
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Fang K, Han L, Liu Y, Fang J, Wang X, Liu T. Enantioselective bioaccumulation and detoxification mechanisms of earthworms (Eisenia fetida) exposed to mandipropamid. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 796:149051. [PMID: 34280637 DOI: 10.1016/j.scitotenv.2021.149051] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 05/27/2023]
Abstract
As a novel chiral amide fungicide, the enantioselective behaviors of mandipropamid in the soil environment are unclear. Furthermore, there is a need to understand the stress response mechanisms of soil organisms exposed to mandipropamid isomers. Therefore, the selective bioaccumulation of mandipropamid isomers and detoxification mechanisms of earthworms (Eisenia fetida) were investigated in this study. Our results suggested that the enantioselective bioaccumulation of mandipropamid in earthworms occurred with the preferential enrichment of S-(+)-isomer. The activities of detoxification enzymes, such as cytochrome P450 (CYP450), glutathione-S-transferases (GST), and carboxylesterase (CarE), changed significantly upon exposure to S-(+)- and R-(-)-mandipropamid (particularly for CYP450 and GST). A transcriptome analysis revealed that more differentially expressed genes (DEGs) were observed under S-(+)-isomer exposure (15,798) than those under R-(-)-isomer exposure (12,222), as compared to the control group. These DEGs were mainly enriched in bile secretion and thyroid hormone signaling pathways, which were related to the detoxification process in earthworms. Moreover, the 20 DEGs, which exhibited the most profound changes (such as CYP2 and CYP3A4) in these pathways, were screened, clustered, and observed to be mainly involved in regulating the detoxification function of earthworm cells. These results indicated that detoxification systems played an essential role in the stress response to mandipropamid exposure. Additionally, earthworms were more sensitive to the stress induced by S-(+)-mandipropamid than that induced by R-(-)-mandipropamid. This is the first study to elucidate the mandipropamid detoxification mechanism of earthworms at the enantiomer level, which can be beneficial for remediating chiral pollutants.
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Affiliation(s)
- Kuan Fang
- Tobacco Research Institute of Chinese Academy of Agricultural Sciences (CAAS), Qingdao 266101, PR China; Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Lingxi Han
- Tobacco Research Institute of Chinese Academy of Agricultural Sciences (CAAS), Qingdao 266101, PR China; Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Yalei Liu
- Tobacco Research Institute of Chinese Academy of Agricultural Sciences (CAAS), Qingdao 266101, PR China; Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Jianwei Fang
- Tobacco Research Institute of Chinese Academy of Agricultural Sciences (CAAS), Qingdao 266101, PR China; Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Xiuguo Wang
- Tobacco Research Institute of Chinese Academy of Agricultural Sciences (CAAS), Qingdao 266101, PR China
| | - Tong Liu
- Tobacco Research Institute of Chinese Academy of Agricultural Sciences (CAAS), Qingdao 266101, PR China.
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5
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Kohno T, Konno T, Kikuchi S, Kondoh M, Kojima T. Translocation of LSR from tricellular corners causes macropinocytosis at cell-cell interface as a trigger for breaking out of contact inhibition. FASEB J 2021; 35:e21742. [PMID: 34403506 DOI: 10.1096/fj.202100299r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/28/2021] [Accepted: 06/04/2021] [Indexed: 12/29/2022]
Abstract
Withdrawal from contact inhibition is necessary for epithelial cancer precursor cells to initiate cell growth and motility. Nevertheless, little is understood about the mechanism for the sudden initiation of cell growth under static conditions. We focused on cellular junctions as one region where breaking out of contact inhibition occurs. In well-differentiated endometrial cancer cells, Sawano, the ligand administration for tricellular tight junction protein LSR, which transiently decreased the robust junction property, caused an abrupt increase in cell motility and consequent excessive multilayered cell growth despite being under contact inhibition conditions. We observed that macropinocytosis essentially and temporarily occurred as an antecedent event for the above process at intercellular junctions without disruption of the junction apparatus but not at the apical plasma membrane. Collectively, we concluded that the formation of macropinocytosis, which is derived from tight junction-mediated signaling, was triggered for the initiation of cell growth in static precancerous epithelium.
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Affiliation(s)
- Takayuki Kohno
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University, Sapporo, Japan
| | - Takumi Konno
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University, Sapporo, Japan
| | - Shin Kikuchi
- Department of Anatomy, Sapporo Medical University, Sapporo, Japan
| | - Masuo Kondoh
- Drug Innovation Center, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Takashi Kojima
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University, Sapporo, Japan
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6
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Tharp KM, Higuchi-Sanabria R, Timblin GA, Ford B, Garzon-Coral C, Schneider C, Muncie JM, Stashko C, Daniele JR, Moore AS, Frankino PA, Homentcovschi S, Manoli SS, Shao H, Richards AL, Chen KH, Hoeve JT, Ku GM, Hellerstein M, Nomura DK, Saijo K, Gestwicki J, Dunn AR, Krogan NJ, Swaney DL, Dillin A, Weaver VM. Adhesion-mediated mechanosignaling forces mitohormesis. Cell Metab 2021; 33:1322-1341.e13. [PMID: 34019840 PMCID: PMC8266765 DOI: 10.1016/j.cmet.2021.04.017] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/09/2021] [Accepted: 04/26/2021] [Indexed: 12/11/2022]
Abstract
Mitochondria control eukaryotic cell fate by producing the energy needed to support life and the signals required to execute programed cell death. The biochemical milieu is known to affect mitochondrial function and contribute to the dysfunctional mitochondrial phenotypes implicated in cancer and the morbidities of aging. However, the physical characteristics of the extracellular matrix are also altered in cancerous and aging tissues. Here, we demonstrate that cells sense the physical properties of the extracellular matrix and activate a mitochondrial stress response that adaptively tunes mitochondrial function via solute carrier family 9 member A1-dependent ion exchange and heat shock factor 1-dependent transcription. Overall, our data indicate that adhesion-mediated mechanosignaling may play an unappreciated role in the altered mitochondrial functions observed in aging and cancer.
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Affiliation(s)
- Kevin M Tharp
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ryo Higuchi-Sanabria
- Department of Molecular & Cellular Biology, Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA 94597, USA
| | - Greg A Timblin
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Breanna Ford
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA 94720, USA; Novartis, Berkeley Center for Proteomics and Chemistry Technologies and Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Carlos Garzon-Coral
- Chemical Engineering Department, Stanford University, Stanford, CA 94305, USA
| | - Catherine Schneider
- Novartis, Berkeley Center for Proteomics and Chemistry Technologies and Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Jonathon M Muncie
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Connor Stashko
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Joseph R Daniele
- MD Anderson Cancer Center, South Campus Research, Houston, CA 77054, USA
| | - Andrew S Moore
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Phillip A Frankino
- Department of Molecular & Cellular Biology, Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA 94597, USA
| | - Stefan Homentcovschi
- Department of Molecular & Cellular Biology, Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA 94597, USA
| | - Sagar S Manoli
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Hao Shao
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alicia L Richards
- Quantitative Biosciences Institute (QBI), J. David Gladstone Institutes, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Kuei-Ho Chen
- Quantitative Biosciences Institute (QBI), J. David Gladstone Institutes, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Johanna Ten Hoeve
- UCLA Metabolomics Center, Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Gregory M Ku
- Diabetes Center, Division of Endocrinology and Metabolism, Department of Medicine, UCSF, San Francisco, CA 94143, USA
| | - Marc Hellerstein
- Novartis, Berkeley Center for Proteomics and Chemistry Technologies and Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Daniel K Nomura
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA 94720, USA; Novartis, Berkeley Center for Proteomics and Chemistry Technologies and Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Karou Saijo
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Jason Gestwicki
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alexander R Dunn
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Nevan J Krogan
- Quantitative Biosciences Institute (QBI), J. David Gladstone Institutes, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Danielle L Swaney
- Quantitative Biosciences Institute (QBI), J. David Gladstone Institutes, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Andrew Dillin
- Department of Molecular & Cellular Biology, Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA 94597, USA
| | - Valerie M Weaver
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Bioengineering and Therapeutic Sciences and Department of Radiation Oncology, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, and The Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA.
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7
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Romani P, Valcarcel-Jimenez L, Frezza C, Dupont S. Crosstalk between mechanotransduction and metabolism. Nat Rev Mol Cell Biol 2021; 22:22-38. [PMID: 33188273 DOI: 10.1038/s41580-020-00306-w] [Citation(s) in RCA: 183] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2020] [Indexed: 12/22/2022]
Abstract
Mechanical forces shape cells and tissues during development and adult homeostasis. In addition, they also signal to cells via mechanotransduction pathways to control cell proliferation, differentiation and death. These processes require metabolism of nutrients for both energy generation and biosynthesis of macromolecules. However, how cellular mechanics and metabolism are connected is still poorly understood. Here, we discuss recent evidence indicating how the mechanical cues exerted by the extracellular matrix (ECM), cell-ECM and cell-cell adhesion complexes influence metabolic pathways. Moreover, we explore the energy and metabolic requirements associated with cell mechanics and ECM remodelling, implicating a reciprocal crosstalk between cell mechanics and metabolism.
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Affiliation(s)
- Patrizia Romani
- Department of Molecular Medicine, University of Padua Medical School, Padua, Italy
| | | | - Christian Frezza
- MRC Cancer Unit, University of Cambridge, Hutchison/MRC Research Centre, Cambridge, UK.
| | - Sirio Dupont
- Department of Molecular Medicine, University of Padua Medical School, Padua, Italy.
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Liu Y, White KA, Barber DL. Intracellular pH Regulates Cancer and Stem Cell Behaviors: A Protein Dynamics Perspective. Front Oncol 2020; 10:1401. [PMID: 32983969 PMCID: PMC7479815 DOI: 10.3389/fonc.2020.01401] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/02/2020] [Indexed: 12/12/2022] Open
Abstract
The International Society of Cancer Metabolism (ISCaM) meeting on Cancer Metabolic Rewiring, held in Braga Portugal in October 2019, provided an outstanding forum for investigators to present current findings and views, and discuss ideas and future directions on fundamental biology as well as clinical translations. The first session on Cancer pH Dynamics was preceded by the opening keynote presentation from our group entitled Intracellular pH Regulation of Protein Dynamics: From Cancer to Stem Cell Behaviors. In this review we introduce a brief background on intracellular pH (pHi) dynamics, including how it is regulated as well as functional consequences, summarize key findings included in our presentation, and conclude with perspectives on how understanding the role of pHi dynamics in stem cells can be relevant for understanding how pHi dynamics enables cancer progression.
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Affiliation(s)
- Yi Liu
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, United States
| | - Katharine A White
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, United States
| | - Diane L Barber
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, United States
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9
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Sin WC, Tam N, Moniz D, Lee C, Church J. Na/H exchanger NHE1 acts upstream of rho GTPases to promote neurite outgrowth. J Cell Commun Signal 2020; 14:325-333. [PMID: 32144636 DOI: 10.1007/s12079-020-00556-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 02/28/2020] [Indexed: 02/05/2023] Open
Abstract
Na+/H+ exchanger NHE1, a major determinant of intracellular pH (pHi) in mammalian central neurons, promotes neurite outgrowth under both basal and netrin-1-stimulated conditions. The small GTP binding proteins and their effectors have a dominant role in netrin-1-stimulated neurite outgrowth. Since NHE1 has been shown previously to work downstream of the Rho GTPases-mediated polarized membrane protrusion in non-neuronal cells, we examined whether NHE1 has a similar relationship with Cdc42, Rac1 and RhoA in neuronal morphogenesis. Interestingly, our results suggest the possibility that NHE1 acting upstream of Rho GTPases to promote neurite outgrowth induced by netrin-1. First, we found that netrin-1-induced increases in the activities of Rho GTPases using FRET (Forster Resonance Energy Transfer) analyses in individual growth cones; furthermore, their increased activities were abolished by cariporide, a specific NHE1 inhibitor. Second, NHE1 inhibition had no effect on neurite retraction induced by L-α-Lysophosphatidic acid (LPA), a potent RhoA activator. The regulation of Rho GTPases by NHE1 was further evidenced by reduced Rac1, Cdc42 and RhoA activities in NHE1-null neurons. Taken together, our findings suggest that NHE1-dependent neuronal morphogenesis involves the activation of Rho-family of small GTPases.
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Affiliation(s)
- Wun Chey Sin
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada.
| | - Nicola Tam
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - David Moniz
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Connie Lee
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - John Church
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
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Wakabayashi S, Morihara H, Yokoe S, Nakagawa T, Moriwaki K, Tomoda K, Asahi M. Overexpression of Na +/H + exchanger 1 specifically induces cell death in human iPS cells via sustained activation of the Rho kinase ROCK. J Biol Chem 2019; 294:19577-19588. [PMID: 31723030 DOI: 10.1074/jbc.ra119.010329] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 11/04/2019] [Indexed: 01/15/2023] Open
Abstract
Understanding the specific properties of human induced pluripotent stem cells (iPSCs) is important for quality control of iPSCs. Having incidentally discovered that overexpression of plasma membrane Na+/H+ exchanger 1 (NHE1) induces cell death in iPSCs, we investigated the mechanism of NHE1-induced cell death. Doxycycline-induced NHE1 overexpression arrested cell growth, and nearly all cells were killed by a necrotic process within 72 h. NHE1 overexpression led to sustained activation of Rho-associated coiled-coil kinase (ROCK), accompanied by dramatic changes in cell shape, cell elongation, and swelling of peripheral cells in iPSC colonies, as well as marked stress fiber formation. The ROCK inhibitor Y27632 reduced NHE1-induced cell death. ROCK-dependent phenotypes were suppressed by a loss-of-function mutation of NHE1 and inhibited by an inhibitor of NHE1 activity, indicating that NHE1-mediated transport activity is required. Moreover, ROCK was activated by trimethylamine treatment-mediated cytosolic alkalinization and accumulated in the plasma membrane near NHE1 in peripheral iPSCs of cell colonies. By contrast, cell death did not occur in mesendoderm-like cells that had differentiated from iPSCs, indicating that the NHE1-mediated effects were specific for iPSCs. These results suggest that NHE1 overexpression specifically induces death of iPSCs via sustained ROCK activation, probably caused by an increase in local pH near NHE1. Finally, monensin, a Na+/H+ exchange ionophore, selectively killed iPSCs, suggesting that monensin could help eliminate iPSCs that remain after differentiation, a strategy that might be useful for improving regenerative medicine.
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Affiliation(s)
- Shigeo Wakabayashi
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Takatsuki City, Osaka 569-8686, Japan
| | - Hirofumi Morihara
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Takatsuki City, Osaka 569-8686, Japan
| | - Shunichi Yokoe
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Takatsuki City, Osaka 569-8686, Japan
| | - Takatoshi Nakagawa
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Takatsuki City, Osaka 569-8686, Japan
| | - Kazumasa Moriwaki
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Takatsuki City, Osaka 569-8686, Japan
| | - Kiichiro Tomoda
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Takatsuki City, Osaka 569-8686, Japan
| | - Michio Asahi
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Takatsuki City, Osaka 569-8686, Japan
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11
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Pedersen SF, Counillon L. The SLC9A-C Mammalian Na +/H + Exchanger Family: Molecules, Mechanisms, and Physiology. Physiol Rev 2019; 99:2015-2113. [PMID: 31507243 DOI: 10.1152/physrev.00028.2018] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Na+/H+ exchangers play pivotal roles in the control of cell and tissue pH by mediating the electroneutral exchange of Na+ and H+ across cellular membranes. They belong to an ancient family of highly evolutionarily conserved proteins, and they play essential physiological roles in all phyla. In this review, we focus on the mammalian Na+/H+ exchangers (NHEs), the solute carrier (SLC) 9 family. This family of electroneutral transporters constitutes three branches: SLC9A, -B, and -C. Within these, each isoform exhibits distinct tissue expression profiles, regulation, and physiological roles. Some of these transporters are highly studied, with hundreds of original articles, and some are still only rudimentarily understood. In this review, we present and discuss the pioneering original work as well as the current state-of-the-art research on mammalian NHEs. We aim to provide the reader with a comprehensive view of core knowledge and recent insights into each family member, from gene organization over protein structure and regulation to physiological and pathophysiological roles. Particular attention is given to the integrated physiology of NHEs in the main organ systems. We provide several novel analyses and useful overviews, and we pinpoint main remaining enigmas, which we hope will inspire novel research on these highly versatile proteins.
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Affiliation(s)
- S F Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - L Counillon
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
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12
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Huetsch JC, Walker J, Undem C, Lade J, Yun X, Baksh S, Jiang H, Lai N, Shimoda LA. Rho kinase and Na + /H + exchanger mediate endothelin-1-induced pulmonary arterial smooth muscle cell proliferation and migration. Physiol Rep 2019; 6:e13698. [PMID: 29756391 PMCID: PMC5949284 DOI: 10.14814/phy2.13698] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 04/05/2018] [Accepted: 04/07/2018] [Indexed: 01/04/2023] Open
Abstract
Excessive production of endothelin‐1 (ET‐1) has been observed in almost all forms of pulmonary hypertension. ET‐1, a highly potent vasoconstrictor, can also potentiate pulmonary arterial smooth muscle cell (PASMC) growth and migration, both of which contribute to the vascular remodeling that occurs during the development of pulmonary hypertension. Increasing evidence indicates that alkalinization of intracellular pH (pHi), typically due to activation of Na+/H+ exchange (NHE), is associated with enhanced PASMC proliferation and migration. We recently demonstrated that application of exogenous ET‐1 increased NHE activity in murine PASMCs via a mechanism requiring Rho kinase (ROCK). However, whether ROCK and/or increased NHE activity mediate ET‐1‐induced migration and proliferation in PASMCs remains unknown. In this study, we used fluorescent microscopy in transiently cultured PASMCs from distal pulmonary arteries of the rat and the pH‐sensitive dye, BCECF‐AM, to measure changes in resting pHi and NHE activity induced by exposure to exogenous ET‐1 (10−8 mol/L) for 24 h. Cell migration and proliferation in response to ET‐1 were also measured using Transwell assays and BrdU incorporation, respectively. We found that application of exogenous ET‐1 had no effect on NHE1 expression, but increased pHi, NHE activity, migration, and proliferation in rat PASMCs. Pharmacologic inhibition of NHE or ROCK prevented the ET‐1‐induced changes in cell function (proliferation and migration). Our results indicate that ET‐1 modulates PASMC migration and proliferation via changes in pHi homeostasis through a pathway involving ROCK.
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Affiliation(s)
- John C Huetsch
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD
| | - Jasmine Walker
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD
| | - Clark Undem
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD
| | - Julie Lade
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD
| | - Xin Yun
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD
| | - Syeda Baksh
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD
| | - Haiyang Jiang
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD
| | - Ning Lai
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD
| | - Larissa A Shimoda
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD
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13
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Structural and Functional Changes in the Na +/H + Exchanger Isoform 1, Induced by Erk1/2 Phosphorylation. Int J Mol Sci 2019; 20:ijms20102378. [PMID: 31091671 PMCID: PMC6566726 DOI: 10.3390/ijms20102378] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 12/15/2022] Open
Abstract
The human Na+/H+ exchanger isoform 1 (NHE1) is a plasma membrane transport protein that plays an important role in pH regulation in mammalian cells. Because of the generation of protons by intermediary metabolism as well as the negative membrane potential, protons accumulate within the cytosol. Extracellular signal-regulated kinase (ERK)-mediated regulation of NHE1 is important in several human pathologies including in the myocardium in heart disease, as well as in breast cancer as a trigger for growth and metastasis. NHE1 has a N-terminal, a 500 amino acid membrane domain, and a C-terminal 315 amino acid cytosolic domain. The C-terminal domain regulates the membrane domain and its effects on transport are modified by protein binding and phosphorylation. Here, we discuss the physiological regulation of NHE1 by ERK, with an emphasis on the critical effects on structure and function. ERK binds directly to the cytosolic domain at specific binding domains. ERK also phosphorylates NHE1 directly at multiple sites, which enhance NHE1 activity with subsequent downstream physiological effects. The NHE1 cytosolic regulatory tail possesses both ordered and disordered regions, and the disordered regions are stabilized by ERK-mediated phosphorylation at a phosphorylation motif. Overall, ERK pathway mediated phosphorylation modulates the NHE1 tail, and affects the activity, structure, and function of this membrane protein.
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14
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Artamonov MV, Sonkusare SK, Good ME, Momotani K, Eto M, Isakson BE, Le TH, Cope EL, Derewenda ZS, Derewenda U, Somlyo AV. RSK2 contributes to myogenic vasoconstriction of resistance arteries by activating smooth muscle myosin and the Na +/H + exchanger. Sci Signal 2018; 11:11/554/eaar3924. [PMID: 30377223 DOI: 10.1126/scisignal.aar3924] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Smooth muscle contraction is triggered when Ca2+/calmodulin-dependent myosin light chain kinase (MLCK) phosphorylates the regulatory light chain of myosin (RLC20). However, blood vessels from Mlck-deficient mouse embryos retain the ability to contract, suggesting the existence of additional regulatory mechanisms. We showed that the p90 ribosomal S6 kinase 2 (RSK2) also phosphorylated RLC20 to promote smooth muscle contractility. Active, phosphorylated RSK2 was present in mouse resistance arteries under normal basal tone, and phosphorylation of RSK2 increased with myogenic vasoconstriction or agonist stimulation. Resistance arteries from Rsk2-deficient mice were dilated and showed reduced myogenic tone and RLC20 phosphorylation. RSK2 phosphorylated Ser19 in RLC in vitro. In addition, RSK2 phosphorylated an activating site in the Na+/H+ exchanger (NHE-1), resulting in cytosolic alkalinization and an increase in intracellular Ca2+ that promotes vasoconstriction. NHE-1 activity increased upon myogenic constriction, and the increase in intracellular pH was suppressed in Rsk2-deficient mice. In pressured arteries, RSK2-dependent activation of NHE-1 was associated with increased intracellular Ca2+ transients, which would be expected to increase MLCK activity, thereby contributing to basal tone and myogenic responses. Accordingly, Rsk2-deficient mice had lower blood pressure than normal littermates. Thus, RSK2 mediates a procontractile signaling pathway that contributes to the regulation of basal vascular tone, myogenic vasoconstriction, and blood pressure and may be a potential therapeutic target in smooth muscle contractility disorders.
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Affiliation(s)
- Mykhaylo V Artamonov
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Swapnil K Sonkusare
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.,Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Miranda E Good
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Ko Momotani
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.,Faculty of Pharmaceutical Sciences, Sanyo-Onoda City University, 1-1-1 Daigaku-dori, Sanyo-Onoda-shi, Yamaguchi 756-0884, Japan
| | - Masumi Eto
- Department of Molecular Physiology and Biophysics, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, USA.,Faculty of Veterinary Medicine, Okayama University of Science, 1-13 Ikoinooka-oka, Imabari, Ehime 794-0085, Japan
| | - Brant E Isakson
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.,Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Thu H Le
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.,Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Eric L Cope
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Zygmunt S Derewenda
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Urszula Derewenda
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Avril V Somlyo
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.
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15
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Guo X, Riobo-Del Galdo NA, Kim EJ, Grant GR, Manning DR. Overlap in signaling between Smoothened and the α subunit of the heterotrimeric G protein G13. PLoS One 2018; 13:e0197442. [PMID: 29763457 PMCID: PMC5953476 DOI: 10.1371/journal.pone.0197442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 05/02/2018] [Indexed: 01/20/2023] Open
Abstract
The Hedgehog family of morphogens has long been known to utilize, through the 7-transmembrane protein Smoothened (Smo), the heterotrimeric G protein Gi in both canonical and noncanonical forms of signaling. Other G proteins, while not specifically utilized by Smo, may nonetheless provide access to some of the events controlled by it. We reported several years ago that the G protein G13 activates one or more forms of the Gli family of transcription factors. While the Gli transcription factors are well known targets for Smo, the uncertain mechanism of activation by G13 and the identity of the targeted Gli(s) limited predictions as to the extent to which G13 might mimic Smo's actions. We evaluate here the potential for overlap in G13 and Smo signaling using C3H10T1/2 and 3T3-L1 cells as models of osteogenesis and adipogenesis, respectively. We find in C3H10T1/2 cells that a constitutively active form of Gα13 (Gα13QL) increases Gli1 mRNA, as does a constitutively active form of Smo (SmoA1). We find as well that Gα13QL induces alkaline phosphatase activity, a marker of osteogenesis, albeit the induction is far less substantial than that achieved by SmoA1. In 3T3-L1 cells both Gα13QL and SmoA1 markedly suppress adipogenic differentiation as determined by triglyceride accumulation. RNA sequencing reveals that Gα13QL and SmoA1 regulate many of the same genes but that quantitative and qualitative differences exist. Differences also exist, we find, between SmoA1 and purmorphamine, an agonist for Smo. Therefore, while comparisons of constitutively active proteins are informative, extrapolations to the setting of agonists require care.
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Affiliation(s)
- Xueshui Guo
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Natalia A. Riobo-Del Galdo
- Leeds Institute of Cancer and Pathology and School of Molecular and Cellular Biology, University of Leeds, United Kingdom
| | - Eun Ji Kim
- Institute of Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Gregory R. Grant
- Institute of Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - David R. Manning
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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16
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Exposing Cell-Itary Confinement: Understanding the Mechanisms of Confined Single Cell Migration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1092:139-157. [DOI: 10.1007/978-3-319-95294-9_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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17
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Asgharzadeh MR, Barar J, Pourseif MM, Eskandani M, Jafari Niya M, Mashayekhi MR, Omidi Y. Molecular machineries of pH dysregulation in tumor microenvironment: potential targets for cancer therapy. BIOIMPACTS : BI 2017; 7:115-133. [PMID: 28752076 PMCID: PMC5524986 DOI: 10.15171/bi.2017.15] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 05/28/2017] [Accepted: 06/06/2017] [Indexed: 12/30/2022]
Abstract
Introduction: Cancer is an intricate disorder/dysfunction of cells that can be defined as a genetic heterogeneity in human disease. Therefore, it is characterized by several adaptive complex hallmarks. Among them, the pH dysregulation appears as a symbol of aberrant functions within the tumor microenvironment (TME). In comparison with normal tissues, in the solid tumors, we face with an irregular acidification and alkalinization of the extracellular and intracellular fluids. Methods: In this study, we comprehensively discussed the most recent reports on the hallmarks of solid tumors to provide deep insights upon the molecular machineries involved in the pH dysregulation of solid tumors and their impacts on the initiation and progression of cancer. Results: The dysregulation of pH in solid tumors is fundamentally related to the Warburg effect and hypoxia, leading to expression of a number of molecular machineries, including: NHE1, H+ pump V-ATPase, CA-9, CA-12, MCT-1, GLUT-1. Activation of proton exchangers and transporters (PETs) gives rise to formation of TME. This condition favors the cancer cells to evade from the anoikis and apoptosis, granting them aggressive and metastasis phenotype, as well as resistance to chemotherapy and radiation therapy. This review aimed to discuss the key molecular changes of tumor cells in terms of bio-energetics and cancer metabolism in relation with pH dysregulation. During this phenomenon, the intra- and extracellular metabolites are altered and/or disrupted. Such molecular alterations provide molecular hallmarks for direct targeting of the PETs by potent relevant inhibitors in combination with conventional cancer therapies as ultimate therapy against solid tumors. Conclusion: Taken all, along with other treatment strategies, targeting the key molecular machineries related to intra- and extracellular metabolisms within the TME is proposed as a novel strategy to inhibit or block PETs that are involved in the pH dysregulation of solid tumors.
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Affiliation(s)
- Mohammad Reza Asgharzadeh
- Department of Biology, Fars Science and Research Branch, Islamic Azad University, Marvdasht, Iran
- Department of Biology, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran
| | - Jaleh Barar
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad M. Pourseif
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Morteza Eskandani
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mojtaba Jafari Niya
- Department of Biology, Fars Science and Research Branch, Islamic Azad University, Marvdasht, Iran
- Department of Biology, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran
| | | | - Yadollah Omidi
- Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
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18
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Abstract
Time-lapse, deep-tissue imaging made possible by advances in intravital microscopy has demonstrated the importance of tumour cell migration through confining tracks in vivo. These tracks may either be endogenous features of tissues or be created by tumour or tumour-associated cells. Importantly, migration mechanisms through confining microenvironments are not predicted by 2D migration assays. Engineered in vitro models have been used to delineate the mechanisms of cell motility through confining spaces encountered in vivo. Understanding cancer cell locomotion through physiologically relevant confining tracks could be useful in developing therapeutic strategies to combat metastasis.
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Affiliation(s)
- Colin D Paul
- Department of Chemical and Biomolecular Engineering and the Institute for NanoBioTechnology, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
| | - Panagiotis Mistriotis
- Department of Chemical and Biomolecular Engineering and the Institute for NanoBioTechnology, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
| | - Konstantinos Konstantopoulos
- Department of Chemical and Biomolecular Engineering and the Institute for NanoBioTechnology, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
- Department of Biomedical Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
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19
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Walker J, Undem C, Yun X, Lade J, Jiang H, Shimoda LA. Role of Rho kinase and Na+/H+ exchange in hypoxia-induced pulmonary arterial smooth muscle cell proliferation and migration. Physiol Rep 2016; 4:4/6/e12702. [PMID: 27009277 PMCID: PMC4814889 DOI: 10.14814/phy2.12702] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/17/2016] [Indexed: 12/21/2022] Open
Abstract
Abnormal proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) are hallmark characteristics of vascular remodeling in pulmonary hypertension induced by chronic hypoxia. In this study, we investigated the role of the Na+/H+ exchanger (NHE) and alterations in intracellular pH (pHi) homeostasis in meditating increased proliferation and migration in PASMCs isolated from resistance‐sized pulmonary arteries from chronically hypoxic rats or from normoxic rats that were exposed to hypoxia ex vivo (1% or 4% O2, 24–96 h). We found that PASMCs exposed to either in vivo or ex vivo hypoxia exhibited greater proliferative and migratory capacity, elevated pHi, and enhanced NHE activity. The NHE inhibitor, ethyl isopropyl amiloride (EIPA), normalized pHi in hypoxic PASMCs and reduced migration by 73% and 45% in cells exposed to in vivo and in vitro hypoxia, respectively. Similarly, EIPA reduced proliferation by 97% and 78% in cells exposed to in vivo and in vitro hypoxia, respectively. We previously demonstrated that NHE isoform 1 (NHE1) is the predominant isoform expressed in PASMCs. The development of hypoxia‐induced pulmonary hypertension and alterations in PASMC pHi homeostasis were prevented in mice deficient for NHE1. We found that short‐term (24 h) ex vivo hypoxic exposure did not alter the expression of NHE1, so we tested the role of Rho kinase (ROCK) as a possible means of increasing NHE activity. In the presence of the ROCK inhibitor, Y‐27632, we found that pHi and NHE activity were normalized and migration and proliferation were reduced in PASMCs exposed to either in vivo (by 68% for migration and 22% for proliferation) or ex vivo (by 43% for migration and 17% for proliferation) hypoxia. From these results, we conclude that during hypoxia, activation of ROCK enhances NHE activity and promotes PASMC migration and proliferation.
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Affiliation(s)
- Jasmine Walker
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Clark Undem
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Xin Yun
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Julie Lade
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Haiyang Jiang
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Larissa A Shimoda
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
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20
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Webb BA, White KA, Grillo-Hill BK, Schönichen A, Choi C, Barber DL. A Histidine Cluster in the Cytoplasmic Domain of the Na-H Exchanger NHE1 Confers pH-sensitive Phospholipid Binding and Regulates Transporter Activity. J Biol Chem 2016; 291:24096-24104. [PMID: 27650500 DOI: 10.1074/jbc.m116.736215] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 09/18/2016] [Indexed: 01/26/2023] Open
Abstract
The Na-H exchanger NHE1 contributes to intracellular pH (pHi) homeostasis in normal cells and the constitutively increased pHi in cancer. NHE1 activity is allosterically regulated by intracellular protons, with greater activity at lower pHi However, the molecular mechanism for pH-dependent NHE1 activity remains incompletely resolved. We report that an evolutionarily conserved cluster of histidine residues located in the C-terminal cytoplasmic domain between two phosphatidylinositol 4,5-bisphosphate binding sites (PI(4,5)P2) of NHE1 confers pH-dependent PI(4,5)P2 binding and regulates NHE1 activity. A GST fusion of the wild type C-terminal cytoplasmic domain of NHE1 showed increased maximum PI(4,5)P2 binding at pH 7.0 compared with pH 7.5. However, pH-sensitive binding is abolished by substitutions of the His-rich cluster to arginine (RXXR3) or alanine (AXXA3), mimicking protonated and neutral histidine residues, respectively, and the RXXR3 mutant had significantly greater PI(4,5)P2 binding than AXXA3. When expressed in cells, NHE1 activity and pHi were significantly increased with NHE1-RXXR3 and decreased with NHE1-AXXA3 compared with wild type NHE1. Additionally, fibroblasts expressing NHE1-RXXR3 had significantly more contractile actin filaments and focal adhesions compared with fibroblasts expressing wild type NHE1, consistent with increased pHi enabling cytoskeletal remodeling. These data identify a molecular mechanism for pH-sensitive PI(4,5)P2 binding regulating NHE1 activity and suggest that the evolutionarily conserved cluster of four histidines in the proximal cytoplasmic domain of NHE1 may constitute a proton modifier site. Moreover, a constitutively activated NHE1-RXXR3 mutant is a new tool that will be useful for studying how increased pHi contributes to cell behaviors, most notably the biology of cancer cells.
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Affiliation(s)
- Bradley A Webb
- From the Department of Cell and Tissue Biology, University of California, San Francisco, California 94143 and
| | - Katharine A White
- From the Department of Cell and Tissue Biology, University of California, San Francisco, California 94143 and
| | - Bree K Grillo-Hill
- From the Department of Cell and Tissue Biology, University of California, San Francisco, California 94143 and
| | - André Schönichen
- From the Department of Cell and Tissue Biology, University of California, San Francisco, California 94143 and
| | - Changhoon Choi
- the Department of Radiation Oncology, Samsung Medical Center, Seoul, South Korea 06351
| | - Diane L Barber
- From the Department of Cell and Tissue Biology, University of California, San Francisco, California 94143 and
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21
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Li X, Augustine A, Sun D, Li L, Fliegel L. Activation of the Na +/H + exchanger in isolated cardiomyocytes through β-Raf dependent pathways. Role of Thr 653 of the cytosolic tail. J Mol Cell Cardiol 2016; 99:65-75. [PMID: 27555478 DOI: 10.1016/j.yjmcc.2016.08.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 08/04/2016] [Accepted: 08/19/2016] [Indexed: 10/21/2022]
Abstract
The mammalian Na+/H+ exchanger isoform 1 (NHE1) is a ubiquitous plasma membrane protein that is a key regulator of intracellular pH in isolated cardiomyocytes. A 500 amino acid membrane domain removes protons and is regulated by a 315 amino acid cytosolic domain. In the myocardium, aberrant regulation of NHE1 contributes to ischemia reperfusion damage and to heart hypertrophy. We examined mechanisms of regulation of NHE1 in the myocardium by endothelin and β-Raf. Endothelin stimulated NHE1 activity and activated Erk-dependent pathways. Inhibition of β-Raf reduced NHE1 activity and Erk-pathway activation. We demonstrated that myocardial β-Raf binds to the C-terminal 182 amino acids of the NHE1 protein and that β-Raf is associated with NHE1 in intact cardiomyocytes. NHE1 was phosphorylated in vivo and the protein kinase inhibitor sorafenib reduced NHE1 phosphorylation levels. Immunoprecipitates of β-Raf from cardiomyocytes phosphorylated the C-terminal 182 amino acids of NHE1 and mass spectrometry analysis showed that amino acid Thr653 was phosphorylated. Mutation of this amino acid to Ala resulted in defective activity while mutation to Asp restored the activity. The results demonstrate that Thr653 is an important regulatory amino acid of NHE1 that is activated through β-Raf dependent pathways by phosphorylation either directly or indirectly by β-Raf, and this affects NHE1 activity.
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Affiliation(s)
- Xiuju Li
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
| | - Aruna Augustine
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
| | - Difei Sun
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada.
| | - Liang Li
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada.
| | - Larry Fliegel
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
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22
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Boscia F, Begum G, Pignataro G, Sirabella R, Cuomo O, Casamassa A, Sun D, Annunziato L. Glial Na(+) -dependent ion transporters in pathophysiological conditions. Glia 2016; 64:1677-97. [PMID: 27458821 DOI: 10.1002/glia.23030] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 06/22/2016] [Accepted: 06/29/2016] [Indexed: 12/12/2022]
Abstract
Sodium dynamics are essential for regulating functional processes in glial cells. Indeed, glial Na(+) signaling influences and regulates important glial activities, and plays a role in neuron-glia interaction under physiological conditions or in response to injury of the central nervous system (CNS). Emerging studies indicate that Na(+) pumps and Na(+) -dependent ion transporters in astrocytes, microglia, and oligodendrocytes regulate Na(+) homeostasis and play a fundamental role in modulating glial activities in neurological diseases. In this review, we first briefly introduced the emerging roles of each glial cell type in the pathophysiology of cerebral ischemia, Alzheimer's disease, epilepsy, Parkinson's disease, Amyotrophic Lateral Sclerosis, and myelin diseases. Then, we discussed the current knowledge on the main roles played by the different glial Na(+) -dependent ion transporters, including Na(+) /K(+) ATPase, Na(+) /Ca(2+) exchangers, Na(+) /H(+) exchangers, Na(+) -K(+) -Cl(-) cotransporters, and Na(+) - HCO3- cotransporter in the pathophysiology of the diverse CNS diseases. We highlighted their contributions in cell survival, synaptic pathology, gliotransmission, pH homeostasis, and their role in glial activation, migration, gliosis, inflammation, and tissue repair processes. Therefore, this review summarizes the foundation work for targeting Na(+) -dependent ion transporters in glia as a novel strategy to control important glial activities associated with Na(+) dynamics in different neurological disorders. GLIA 2016;64:1677-1697.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Gulnaz Begum
- Department of Neurology, University of Pittsburgh Medical School
| | - Giuseppe Pignataro
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Rossana Sirabella
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Ornella Cuomo
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Antonella Casamassa
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh Medical School.,Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, Pennsylvania, 15213
| | - Lucio Annunziato
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
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23
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Watts BA, George T, Badalamenti A, Good DW. High-mobility group box 1 inhibits HCO3- absorption in the medullary thick ascending limb through RAGE-Rho-ROCK-mediated inhibition of basolateral Na+/H+ exchange. Am J Physiol Renal Physiol 2016; 311:F600-13. [PMID: 27358052 DOI: 10.1152/ajprenal.00185.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 06/27/2016] [Indexed: 02/07/2023] Open
Abstract
High-mobility group box 1 (HMGB1) is a nuclear protein released extracellularly in response to infection or injury, where it activates immune responses and contributes to the pathogenesis of kidney dysfunction in sepsis and sterile inflammatory disorders. Recently, we demonstrated that HMGB1 inhibits HCO3 (-) absorption in perfused rat medullary thick ascending limbs (MTAL) through a basolateral receptor for advanced glycation end products (RAGE)-dependent pathway that is additive to Toll-like receptor 4 (TLR4)-ERK-mediated inhibition by LPS (Good DW, George T, Watts BA III. Am J Physiol Renal Physiol 309: F720-F730, 2015). Here, we examined signaling and transport mechanisms that mediate inhibition by HMGB1. Inhibition of HCO3 (-) absorption by HMGB1 was eliminated by the Rho-associated kinase (ROCK) inhibitor Y27632 and by a specific inhibitor of Rho, the major upstream activator of ROCK. HMGB1 increased RhoA and ROCK1 activity. HMGB1-induced ROCK1 activation was eliminated by the RAGE antagonist FPS-ZM1 and by inhibition of Rho. The Rho and ROCK inhibitors had no effect on inhibition of HCO3 (-) absorption by bath LPS. Inhibition of HCO3 (-) absorption by HMGB1 was eliminated by bath amiloride, 0 Na(+) bath, and the F-actin stabilizer jasplakinolide, three conditions that selectively prevent inhibition of MTAL HCO3 (-) absorption mediated through NHE1. HMGB1 decreased basolateral Na(+)/H(+) exchange activity through activation of ROCK. We conclude that HMGB1 inhibits HCO3 (-) absorption in the MTAL through a RAGE-RhoA-ROCK1 signaling pathway coupled to inhibition of NHE1. The HMGB1-RAGE-RhoA-ROCK1 pathway thus represents a potential target to attenuate MTAL dysfunction during sepsis and other inflammatory disorders. HMGB1 and LPS inhibit HCO3 (-) absorption through different receptor signaling and transport mechanisms, which enables these pathogenic mediators to act directly and independently to impair MTAL function.
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Affiliation(s)
- Bruns A Watts
- Department of Internal Medicine, The University of Texas Medical Branch, Galveston, Texas; and
| | - Thampi George
- Department of Internal Medicine, The University of Texas Medical Branch, Galveston, Texas; and
| | - Andrew Badalamenti
- Department of Internal Medicine, The University of Texas Medical Branch, Galveston, Texas; and
| | - David W Good
- Department of Internal Medicine, The University of Texas Medical Branch, Galveston, Texas; and Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, Texas
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The cleaved FAS ligand activates the Na(+)/H(+) exchanger NHE1 through Akt/ROCK1 to stimulate cell motility. Sci Rep 2016; 6:28008. [PMID: 27302366 PMCID: PMC4908414 DOI: 10.1038/srep28008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 05/17/2016] [Indexed: 12/20/2022] Open
Abstract
Transmembrane CD95L (Fas ligand) can be cleaved to release a promigratory soluble ligand, cl-CD95L, which can contribute to chronic inflammation and cancer cell dissemination. The motility signaling pathway elicited by cl-CD95L remains poorly defined. Here, we show that in the presence of cl-CD95L, CD95 activates the Akt and RhoA signaling pathways, which together orchestrate an allosteric activation of the Na+/H+ exchanger NHE1. Pharmacologic inhibition of Akt or ROCK1 independently blocks the cl-CD95L-induced migration. Confirming these pharmacologic data, disruption of the Akt and ROCK1 phosphorylation sites on NHE1 decreases cell migration in cells exposed to cl-CD95L. Together, these findings demonstrate that NHE1 is a novel molecular actor in the CD95 signaling pathway that drives the cl-CD95L-induced cell migration through both the Akt and RhoA signaling pathways.
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Kushida N, Yamaguchi O, Kawashima Y, Akaihata H, Hata J, Ishibashi K, Aikawa K, Kojima Y. Uni-axial stretch induces actin stress fiber reorganization and activates c-Jun NH2 terminal kinase via RhoA and Rho kinase in human bladder smooth muscle cells. BMC Urol 2016; 16:9. [PMID: 26928204 PMCID: PMC4772493 DOI: 10.1186/s12894-016-0127-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 02/23/2016] [Indexed: 01/10/2023] Open
Abstract
Background Excessive mechanical overload may be involved in bladder wall remodelling. Since the activity of Rho kinase is known to be upregulated in the obstructed bladder, we investigate the roles of the RhoA/Rho kinase pathway in mechanical overloaded bladder smooth muscle cells. Methods Human bladder smooth muscle cells were stimulated on silicon culture plates by 15 % elongated uni-axial cyclic stretch at 1 Hz. The activity of c-Jun NH2-terminal kinase was measured by western blotting and actin stress fibers were observed by stained with phallotoxin conjugated with Alexa-Fluor 594. Results The activity of c-Jun NH2-terminal kinase 1 peaked at 30 min (4.7-fold increase vs. before stretch) and this activity was partially abrogated by the RhoA inhibitor, C3 exoenzoyme or by the Rho kinase inhibitor, Y-27632. Stretch induced the strong formation of actin stress fibers and these fibers re-orientated in a direction that was perpendicular to the stretch direction. The average angle of the fibers from the perpendicular to the direction of stretch was significantly different between before, and 4 h after, stretch. Actin stress fibers reorganization was also suppressed by the C3 exoenzyme or Y-27632. Conclusions Bladder smooth muscle cells appear to have elaborate mechanisms for sensing mechanical stress and for adapting to mechanical stress overload by cytoskeletal remodeling and by activating cell growth signals such as c-Jun NH2-terminal kinase via RhoA/Rho kinase pathways.
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Affiliation(s)
- Nobuhiro Kushida
- Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan.
| | - Osamu Yamaguchi
- Division of Bioengineering and LUTD Research, Nihon University School of Engineering, Nihon University, 1, Nakagawara, Tokusada, Tamura, Koriyama, 963-8642, Japan.
| | - Yohei Kawashima
- Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan.
| | - Hidenori Akaihata
- Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan.
| | - Junya Hata
- Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan.
| | - Kei Ishibashi
- Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan.
| | - Ken Aikawa
- Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan.
| | - Yoshiyuki Kojima
- Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan.
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26
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Huetsch J, Shimoda LA. Na(+)/H(+) exchange and hypoxic pulmonary hypertension. Pulm Circ 2015; 5:228-43. [PMID: 26064449 DOI: 10.1086/680213] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/22/2014] [Indexed: 12/24/2022] Open
Abstract
Intracellular pH (pHi) homeostasis is key to the functioning of vascular smooth muscle cells, including pulmonary artery smooth muscle cells (PASMCs). Sodium-hydrogen exchange (NHE) is an important contributor to pHi control in PASMCs. In this review, we examine the role of NHE in PASMC function, in both physiologic and pathologic conditions. In particular, we focus on the contribution of NHE to the PASMC response to hypoxia, considering both acute hypoxic pulmonary vasoconstriction and the development of pulmonary vascular remodeling and pulmonary hypertension in response to chronic hypoxia. Hypoxic pulmonary hypertension remains a disease with limited therapeutic options. Thus, this review explores past efforts at disrupting NHE signaling and discusses the therapeutic potential that such efforts may have in the field of pulmonary hypertension.
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Affiliation(s)
- John Huetsch
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA
| | - Larissa A Shimoda
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA
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27
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AlSuleimani YM, Hiley CR. The GPR55 agonist lysophosphatidylinositol relaxes rat mesenteric resistance artery and induces Ca(2+) release in rat mesenteric artery endothelial cells. Br J Pharmacol 2015; 172:3043-57. [PMID: 25652040 DOI: 10.1111/bph.13107] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 01/11/2015] [Accepted: 02/02/2015] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Lysophosphatidylinositol (LPI), a lipid signalling molecule, activates GPR55 and elevates intracellular Ca(2+). Here, we examine the actions of LPI in the rat resistance mesenteric artery and Ca(2+) responses in endothelial cells isolated from the artery. EXPERIMENTAL APPROACH Vascular responses were studied using wire myographs. Single-cell fluorescence imaging was performed using a MetaFluor system. Hypotensive effects of LPI were assessed using a Biopac system. KEY RESULTS In isolated arteries, LPI-induced vasorelaxation was concentration- and endothelium-dependent and inhibited by CID 16020046, a GPR55 antagonist. The CB1 receptor antagonist AM 251 had no effect, whereas rimonabant and O-1918 significantly potentiated LPI responses. Vasorelaxation was reduced by charybdotoxin and iberiotoxin, alone or combined. LPI decreased systemic arterial pressure. GPR55 is expressed in rat mesenteric artery. LPI caused biphasic elevations of endothelial cell intracellular Ca(2+). Pretreatment with thapsigargin or 2-aminoethoxydiphenyl borate abolished both phases. The PLC inhibitor U73122 attenuated the initial phase and enhanced the second phase, whereas the Rho-associated kinase inhibitor Y-27632 abolished the late phase but not the early phase. CONCLUSIONS AND IMPLICATIONS LPI is an endothelium-dependent vasodilator in the rat small mesenteric artery and a hypotensive agent. The vascular response involves activation of Ca(2+)-sensitive K(+) channels and is not mediated by CB1 receptors, but unexpectedly enhanced by antagonists of the 'endothelial anandamide' receptor. In endothelial cells, LPI utilizes PLC-IP3 and perhaps ROCK-RhoA pathways to elevate intracellular Ca(2+). Overall, these findings support an endothelial site of action for LPI and suggest a possible role for GPR55 in vasculature.
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Affiliation(s)
- Y M AlSuleimani
- Department of Pharmacology, University of Cambridge, Cambridge, UK.,Department of Pharmacology and Clinical Pharmacy, College of Medicine and Health Sciences, Sultan Qaboos University, Alkoudh, Sultanate of Oman
| | - C R Hiley
- Department of Pharmacology, University of Cambridge, Cambridge, UK
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Na+-H+ exchanger-1 (NHE1) regulation in kidney proximal tubule. Cell Mol Life Sci 2015; 72:2061-74. [PMID: 25680790 DOI: 10.1007/s00018-015-1848-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/28/2015] [Accepted: 01/29/2015] [Indexed: 01/17/2023]
Abstract
The ubiquitously expressed plasma membrane Na(+)-H(+) exchanger NHE1 is a 12 transmembrane-spanning protein that directs important cell functions such as homeostatic intracellular volume and pH control. The 315 amino acid cytosolic tail of NHE1 binds plasma membrane phospholipids and multiple proteins that regulate additional, ion-translocation independent functions. This review focuses on NHE1 structure/function relationships, as well as the role of NHE1 in kidney proximal tubule functions, including pH regulation, vectorial Na(+) transport, cell volume control and cell survival. The implications of these functions are particularly critical in the setting of progressive, albuminuric kidney diseases, where the accumulation of reabsorbed fatty acids leads to disruption of NHE1-membrane phospholipid interactions and tubular atrophy, which is a poor prognostic factor for progression to end stage renal disease. This review amplifies the vital role of the proximal tubule NHE1 Na(+)-H(+) exchanger as a kidney cell survival factor.
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29
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Wallert MA, Hammes D, Nguyen T, Kiefer L, Berthelsen N, Kern A, Anderson-Tiege K, Shabb JB, Muhonen WW, Grove BD, Provost JJ. RhoA Kinase (Rock) and p90 Ribosomal S6 Kinase (p90Rsk) phosphorylation of the sodium hydrogen exchanger (NHE1) is required for lysophosphatidic acid-induced transport, cytoskeletal organization and migration. Cell Signal 2015; 27:498-509. [PMID: 25578862 DOI: 10.1016/j.cellsig.2015.01.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 01/03/2015] [Indexed: 12/28/2022]
Abstract
The sodium hydrogen exchanger isoform one (NHE1) plays a critical role coordinating asymmetric events at the leading edge of migrating cells and is regulated by a number of phosphorylation events influencing both the ion transport and cytoskeletal anchoring required for directed migration. Lysophosphatidic acid (LPA) activation of RhoA kinase (Rock) and the Ras-ERK growth factor pathway induces cytoskeletal reorganization, activates NHE1 and induces an increase in cell motility. We report that both Rock I and II stoichiometrically phosphorylate NHE1 at threonine 653 in vitro using mass spectrometry and reconstituted kinase assays. In fibroblasts expressing NHE1 alanine mutants for either Rock (T653A) or ribosomal S6 kinase (Rsk; S703A) we show that each site is partially responsible for the LPA-induced increase in transport activity while NHE1 phosphorylation by either Rock or Rsk at their respective site is sufficient for LPA stimulated stress fiber formation and migration. Furthermore, mutation of either T653 or S703 leads to a higher basal pH level and a significantly higher proliferation rate. Our results identify the direct phosphorylation of NHE1 by Rock and suggest that both RhoA and Ras pathways mediate NHE1-dependent ion transport and migration in fibroblasts.
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Affiliation(s)
- Mark A Wallert
- Minnesota State University Moorhead, Department of Biosciences, Moorhead, MN, USA
| | - Daniel Hammes
- Minnesota State University Moorhead, Department of Biosciences, Moorhead, MN, USA
| | - Tony Nguyen
- Minnesota State University Moorhead, Department of Biosciences, Moorhead, MN, USA
| | - Lea Kiefer
- University of San Diego, Department of Chemistry and Biochemistry, San Diego, CA, USA
| | - Nick Berthelsen
- Minnesota State University Moorhead, Department of Biosciences, Moorhead, MN, USA
| | - Andrew Kern
- Minnesota State University Moorhead, Department of Biosciences, Moorhead, MN, USA
| | | | - John B Shabb
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, USA
| | - Wallace W Muhonen
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, USA
| | - Bryon D Grove
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, USA
| | - Joseph J Provost
- University of San Diego, Department of Chemistry and Biochemistry, San Diego, CA, USA.
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Stroka KM, Gu Z, Sun SX, Konstantopoulos K. Bioengineering paradigms for cell migration in confined microenvironments. Curr Opin Cell Biol 2014; 30:41-50. [PMID: 24973724 DOI: 10.1016/j.ceb.2014.06.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/27/2014] [Accepted: 06/04/2014] [Indexed: 12/25/2022]
Abstract
Cell migration is a fundamental process underlying diverse (patho)physiological phenomena. The classical understanding of the molecular mechanisms of cell migration has been based on in vitro studies on two-dimensional substrates. More recently, mounting evidence from intravital studies has shown that during metastasis, tumor cells must navigate complex microenvironments in vivo, including narrow, pre-existing microtracks created by anatomical structures. It is becoming apparent that unraveling the mechanisms of confined cell migration in this context requires a multi-disciplinary approach through integration of in vivo and in vitro studies, along with sophisticated bioengineering techniques and mathematical modeling. Here, we highlight such an approach that has led to discovery of a new model for cell migration in confined microenvironments (i.e., the Osmotic Engine Model).
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Affiliation(s)
- Kimberly M Stroka
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA; Johns Hopkins Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, MD 21218, USA; Johns Hopkins Physical Sciences - Oncology Center, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Zhizhan Gu
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA; Johns Hopkins Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, MD 21218, USA; Johns Hopkins Physical Sciences - Oncology Center, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sean X Sun
- Johns Hopkins Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, MD 21218, USA; Johns Hopkins Physical Sciences - Oncology Center, The Johns Hopkins University, Baltimore, MD 21218, USA; Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Konstantinos Konstantopoulos
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA; Johns Hopkins Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, MD 21218, USA; Johns Hopkins Physical Sciences - Oncology Center, The Johns Hopkins University, Baltimore, MD 21218, USA.
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31
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Uria-Avellanal C, Robertson NJ. Na⁺/H⁺ exchangers and intracellular pH in perinatal brain injury. Transl Stroke Res 2014; 5:79-98. [PMID: 24452957 PMCID: PMC3913853 DOI: 10.1007/s12975-013-0322-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 12/23/2013] [Accepted: 12/30/2013] [Indexed: 12/12/2022]
Abstract
Encephalopathy consequent on perinatal hypoxia–ischemia occurs in 1–3 per 1,000 term births in the UK and frequently leads to serious and tragic consequences that devastate lives and families, with huge financial burdens for society. Although the recent introduction of cooling represents a significant advance, only 40 % survive with normal neurodevelopmental function. There is thus a significant unmet need for novel, safe, and effective therapies to optimize brain protection following brain injury around birth. The Na+/H+ exchanger (NHE) is a membrane protein present in many mammalian cell types. It is involved in regulating intracellular pH and cell volume. NHE1 is the most abundant isoform in the central nervous system and plays a role in cerebral damage after hypoxia–ischemia. Excessive NHE activation during hypoxia–ischemia leads to intracellular Na+ overload, which subsequently promotes Ca2+ entry via reversal of the Na+/Ca2+ exchanger. Increased cytosolic Ca2+ then triggers the neurotoxic cascade. Activation of NHE also leads to rapid normalization of pHi and an alkaline shift in pHi. This rapid recovery of brain intracellular pH has been termed pH paradox as, rather than causing cells to recover, this rapid return to normal and overshoot to alkaline values is deleterious to cell survival. Brain pHi changes are closely involved in the control of cell death after injury: an alkalosis enhances excitability while a mild acidosis has the opposite effect. We have observed a brain alkalosis in 78 babies with neonatal encephalopathy serially studied using phosphorus-31 magnetic resonance spectroscopy during the first year after birth (151 studies throughout the year including 56 studies of 50 infants during the first 2 weeks after birth). An alkaline brain pHi was associated with severely impaired outcome; the degree of brain alkalosis was related to the severity of brain injury on MRI and brain lactate concentration; and a persistence of an alkaline brain pHi was associated with cerebral atrophy on MRI. Experimental animal models of hypoxia–ischemia show that NHE inhibitors are neuroprotective. Here, we review the published data on brain pHi in neonatal encephalopathy and the experimental studies of NHE inhibition and neuroprotection following hypoxia–ischemia.
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Affiliation(s)
- Cristina Uria-Avellanal
- Neonatology, Institute for Women's Health, University College London, 74 Huntley Street, 4th floor, Room 401, London, WC1E 6AU, UK
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Proton-sensitive cation channels and ion exchangers in ischemic brain injury: new therapeutic targets for stroke? Prog Neurobiol 2014; 115:189-209. [PMID: 24467911 DOI: 10.1016/j.pneurobio.2013.12.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/28/2013] [Accepted: 12/24/2013] [Indexed: 12/13/2022]
Abstract
Ischemic brain injury results from complicated cellular mechanisms. The present therapy for acute ischemic stroke is limited to thrombolysis with the recombinant tissue plasminogen activator (rtPA) and mechanical recanalization. Therefore, a better understanding of ischemic brain injury is needed for the development of more effective therapies. Disruption of ionic homeostasis plays an important role in cell death following cerebral ischemia. Glutamate receptor-mediated ionic imbalance and neurotoxicity have been well established in cerebral ischemia after stroke. However, non-NMDA receptor-dependent mechanisms, involving acid-sensing ion channel 1a (ASIC1a), transient receptor potential melastatin 7 (TRPM7), and Na(+)/H(+) exchanger isoform 1 (NHE1), have recently emerged as important players in the dysregulation of ionic homeostasis in the CNS under ischemic conditions. These H(+)-sensitive channels and/or exchangers are expressed in the majority of cell types of the neurovascular unit. Sustained activation of these proteins causes excessive influx of cations, such as Ca(2+), Na(+), and Zn(2+), and leads to ischemic reperfusion brain injury. In this review, we summarize recent pre-clinical experimental research findings on how these channels/exchangers are regulated in both in vitro and in vivo models of cerebral ischemia. The blockade or transgenic knockdown of these proteins was shown to be neuroprotective in these ischemia models. Taken together, these non-NMDA receptor-dependent mechanisms may serve as novel therapeutic targets for stroke intervention.
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33
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Hendus-Altenburger R, Kragelund BB, Pedersen SF. Structural dynamics and regulation of the mammalian SLC9A family of Na⁺/H⁺ exchangers. CURRENT TOPICS IN MEMBRANES 2014; 73:69-148. [PMID: 24745981 DOI: 10.1016/b978-0-12-800223-0.00002-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mammalian Na⁺/H⁺ exchangers of the SLC9A family are widely expressed and involved in numerous essential physiological processes. Their primary function is to mediate the 1:1 exchange of Na⁺ for H⁺ across the membrane in which they reside, and they play central roles in regulation of body, cellular, and organellar pH. Their function is tightly regulated through mechanisms involving interactions with multiple protein and lipid-binding partners, phosphorylations, and other posttranslational modifications. Biochemical and mutational analyses indicate that the SLC9As have a short intracellular N-terminus, 12 transmembrane (TM) helices necessary and sufficient for ion transport, and a C-terminal cytoplasmic tail region with essential regulatory roles. No high-resolution structures of the SLC9As exist; however, models based on crystal structures of the bacterial NhaAs support the 12 TM organization and suggest that TMIV and XI may form a central part of the ion-translocation pathway, whereas pH sensing may involve TMII, TMIX, and several intracellular loops. Similar to most ion transporters studied, SLC9As likely exist as coupled dimers in the membrane, and this appears to be important for the well-studied cooperativity of H⁺ binding. The aim of this work is to summarize and critically discuss the currently available evidence on the structural dynamics, regulation, and binding partner interactions of SLC9As, focusing in particular on the most widely studied isoform, SLC9A1/NHE1. Further, novel bioinformatic and structural analyses are provided that to some extent challenge the existing paradigm on how ions are transported by mammalian SLC9As.
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Affiliation(s)
- Ruth Hendus-Altenburger
- Section for Biomolecular Sciences, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Section for Cell and Developmental Biology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Birthe B Kragelund
- Section for Biomolecular Sciences, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Stine Falsig Pedersen
- Section for Cell and Developmental Biology, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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Stock C, Ludwig FT, Hanley PJ, Schwab A. Roles of ion transport in control of cell motility. Compr Physiol 2013; 3:59-119. [PMID: 23720281 DOI: 10.1002/cphy.c110056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell motility is an essential feature of life. It is essential for reproduction, propagation, embryonic development, and healing processes such as wound closure and a successful immune defense. If out of control, cell motility can become life-threatening as, for example, in metastasis or autoimmune diseases. Regardless of whether ciliary/flagellar or amoeboid movement, controlled motility always requires a concerted action of ion channels and transporters, cytoskeletal elements, and signaling cascades. Ion transport across the plasma membrane contributes to cell motility by affecting the membrane potential and voltage-sensitive ion channels, by inducing local volume changes with the help of aquaporins and by modulating cytosolic Ca(2+) and H(+) concentrations. Voltage-sensitive ion channels serve as voltage detectors in electric fields thus enabling galvanotaxis; local swelling facilitates the outgrowth of protrusions at the leading edge while local shrinkage accompanies the retraction of the cell rear; the cytosolic Ca(2+) concentration exerts its main effect on cytoskeletal dynamics via motor proteins such as myosin or dynein; and both, the intracellular and the extracellular H(+) concentration modulate cell migration and adhesion by tuning the activity of enzymes and signaling molecules in the cytosol as well as the activation state of adhesion molecules at the cell surface. In addition to the actual process of ion transport, both, channels and transporters contribute to cell migration by being part of focal adhesion complexes and/or physically interacting with components of the cytoskeleton. The present article provides an overview of how the numerous ion-transport mechanisms contribute to the various modes of cell motility.
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Affiliation(s)
- Christian Stock
- Institute of Physiology II, University of Münster, Münster, Germany.
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35
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Alvarez BV, Villa-Abrille MC. Mitochondrial NHE1: a newly identified target to prevent heart disease. Front Physiol 2013; 4:152. [PMID: 23825461 PMCID: PMC3695379 DOI: 10.3389/fphys.2013.00152] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 06/09/2013] [Indexed: 11/23/2022] Open
Abstract
Mitochondrial damage has been associated with early steps of cardiac dysfunction in heart subjected to ischemic stress, oxidative stress and hypertrophy. A common feature for the mitochondrial deterioration is the loss of the mitochondrial membrane potential (ΔΨ m) with the concomitant irreversible opening of the mitochondrial permeability transition pore (MPTP) which follows the mitochondrial Ca2+ overload, and the subsequent mitochondrial swelling. We have recently characterized the expression of the Na+/H+ exchanger 1 (mNHE1) in mitochondrial membranes. This surprising observation provided a unique target for the prevention of the Ca2+-induced MPTP opening, based on the inhibition of the NHE1 m. In this line, inhibition of NHE1 m activity and/or reduction of NHE1 m expression decreased the Ca2+-induced mitochondrial swelling and the release of reactive oxygen species (ROS) in isolated cardiac mitochondria and preserved the ΔΨ m in isolated cardiomyocytes. Mitochondrial NHE1 thus represents a novel target to prevent cardiac disease, opening new avenues for future research.
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Affiliation(s)
- Bernardo V Alvarez
- Centro de Investigaciones Cardiovasculares, Consejo Nacional de Investigaciones Científicas y Técnicas Facultad de Ciencias Médicas, Universidad Nacional de La Plata La Plata, Argentina
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36
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Provost JJ, Wallert MA. Inside out: targeting NHE1 as an intracellular and extracellular regulator of cancer progression. Chem Biol Drug Des 2013; 81:85-101. [PMID: 23253131 DOI: 10.1111/cbdd.12035] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The sodium hydrogen exchanger isoform one is a critical regulator of intracellular pH, serves as an anchor for the formation of cytoplasmic signaling complexes, and modulates cytoskeletal organization. There is a growing interest in the potential for sodium hydrogen exchanger isoform one as a therapeutic target against cancer. Sodium hydrogen exchanger isoform one transport drives formation of membrane protrusions essential for cell migration and contributes to the establishment of a tumor microenvironment that leads to the rearrangement of the extracellular matrix further supporting tumor progression. Here, we focus on the potential impact that an inexpensive, $100 genome would have in identifying prospective therapeutic targets to treat tumors based upon changes in gene expression and variation of sodium hydrogen exchanger isoform one regulators. In particular, we will focus on the ezrin, radixin, moesin family proteins, calcineurin B homologous proteins, Ras/Raf/MEK/ERK signaling, and phosphoinositide signaling as they relate to the regulation of sodium hydrogen exchanger isoform one in cancer progression.
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Affiliation(s)
- Joseph J Provost
- Center for Biopharmaceutical Research and Production, North Dakota State University, Fargo, ND 58102, USA.
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Schofield AV, Bernard O. Rho-associated coiled-coil kinase (ROCK) signaling and disease. Crit Rev Biochem Mol Biol 2013; 48:301-16. [PMID: 23601011 DOI: 10.3109/10409238.2013.786671] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The small Rho GTPase family of proteins, encompassing the three major G-protein classes Rho, Rac and cell division control protein 42, are key mitogenic signaling molecules that regulate multiple cancer-associated cellular phenotypes including cell proliferation and motility. These proteins are known for their role in the regulation of actin cytoskeletal dynamics, which is achieved through modulating the activity of their downstream effector molecules. The Rho-associated coiled-coil kinase 1 and 2 (ROCK1 and ROCK2) proteins were the first discovered Rho effectors that were primarily established as players in RhoA-mediated stress fiber formation and focal adhesion assembly. It has since been discovered that the ROCK kinases actively phosphorylate a large cohort of actin-binding proteins and intermediate filament proteins to modulate their functions. It is well established that global cellular morphology, as modulated by the three cytoskeletal networks: actin filaments, intermediate filaments and microtubules, is regulated by a variety of accessory proteins whose activities are dependent on their phosphorylation by the Rho-kinases. As a consequence, they regulate many key cellular functions associated with malignancy, including cell proliferation, motility and viability. In this current review, we focus on the role of the ROCK-signaling pathways in disease including cancer.
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Affiliation(s)
- Alice V Schofield
- St Vincent's Institute of Medical Research, Cytoskeleton and Cancer Unit and Department of Medicine, St Vincent's Hospital, University of Melbourne, Victoria 3065, Australia
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Crevenna AH, Naredi-Rainer N, Schönichen A, Dzubiella J, Barber DL, Lamb DC, Wedlich-Söldner R. Electrostatics control actin filament nucleation and elongation kinetics. J Biol Chem 2013; 288:12102-13. [PMID: 23486468 DOI: 10.1074/jbc.m113.456327] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The actin cytoskeleton is a central mediator of cellular morphogenesis, and rapid actin reorganization drives essential processes such as cell migration and cell division. Whereas several actin-binding proteins are known to be regulated by changes in intracellular pH, detailed information regarding the effect of pH on the actin dynamics itself is still lacking. Here, we combine bulk assays, total internal reflection fluorescence microscopy, fluorescence fluctuation spectroscopy techniques, and theory to comprehensively characterize the effect of pH on actin polymerization. We show that both nucleation and elongation are strongly enhanced at acidic pH, with a maximum close to the pI of actin. Monomer association rates are similarly affected by pH at both ends, although dissociation rates are differentially affected. This indicates that electrostatics control the diffusional encounter but not the dissociation rate, which is critical for the establishment of actin filament asymmetry. A generic model of protein-protein interaction, including electrostatics, explains the observed pH sensitivity as a consequence of charge repulsion. The observed pH effect on actin in vitro agrees with measurements of Listeria propulsion in pH-controlled cells. pH regulation should therefore be considered as a modulator of actin dynamics in a cellular environment.
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Affiliation(s)
- Alvaro H Crevenna
- AG Cellular Dynamics and Cell Patterning, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
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39
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Abstract
The pH gradient in normal cells is tightly controlled by the activity of various pH-regulatory membrane proteins including the isoform protein of the Na(+)/H(+) exchanger (NHE1). NHE1 is constitutively active in a neoplastic microenvironment, dysregulating pH homeostasis and altering the survival, differentiation, and proliferation of cancer cells, thereby causing them to become tumorigenic. Cytoplasmic alkalinization in breast cancer cells occurs as a result of increased NHE1 activity and, while much is known about the pathophysiologic role of NHE1 in tumor progression with regard to ion flux, the regulation of its activity on a molecular level is only recently becoming evident. The membrane domain of NHE1 is sufficient for ion exchange. However, its activity is regulated through the phosphorylation of key amino acids in the cytosolic domain as well as by its interaction with other intracellular proteins and lipids. Here, we review the importance of these regulatory sites and what role they may play in the disrupted functionality of NHE1 in breast cancer metastasis.
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Affiliation(s)
- Schammim R Amith
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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40
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Role of NHE1 in Nociception. PAIN RESEARCH AND TREATMENT 2013; 2013:217864. [PMID: 23431433 PMCID: PMC3572692 DOI: 10.1155/2013/217864] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 01/02/2013] [Indexed: 12/14/2022]
Abstract
Intracellular pH is a fundamental parameter to cell function that requires tight homeostasis. In the absence of any regulation, excessive acidification of the cytosol would have the tendency to produce cellular damage. Mammalian Na(+)/H(+) exchangers (NHEs) are electroneutral Na(+)-dependent proteins that exchange extracellular Na(+) for intracellular H(+). To date, there are 9 identified NHE isoforms where NHE1 is the most ubiquitous member, known as the housekeeping exchanger. NHE1 seems to have a protective role in the ischemia-reperfusion injury and other inflammatory diseases. In nociception, NHE1 is found in neurons along nociceptive pathways, and its pharmacological inhibition increases nociceptive behavior in acute pain models at peripheral and central levels. Electrophysiological studies also show that NHE modulates electrical activity of primary nociceptive terminals. However, its role in neuropathic pain still remains controversial. In humans, NHE1 may be responsible for inflammatory bowel diseases since its expression is reduced in Crohn's disease and ulcerative colitis. The purpose of this work is to provide a review of the evidence about participation of NHE1 in the nociceptive processing.
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Schwab A, Fabian A, Hanley PJ, Stock C. Role of ion channels and transporters in cell migration. Physiol Rev 2013; 92:1865-913. [PMID: 23073633 DOI: 10.1152/physrev.00018.2011] [Citation(s) in RCA: 315] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cell motility is central to tissue homeostasis in health and disease, and there is hardly any cell in the body that is not motile at a given point in its life cycle. Important physiological processes intimately related to the ability of the respective cells to migrate include embryogenesis, immune defense, angiogenesis, and wound healing. On the other side, migration is associated with life-threatening pathologies such as tumor metastases and atherosclerosis. Research from the last ≈ 15 years revealed that ion channels and transporters are indispensable components of the cellular migration apparatus. After presenting general principles by which transport proteins affect cell migration, we will discuss systematically the role of channels and transporters involved in cell migration.
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42
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Undem C, Rios EJ, Maylor J, Shimoda LA. Endothelin-1 augments Na⁺/H⁺ exchange activity in murine pulmonary arterial smooth muscle cells via Rho kinase. PLoS One 2012; 7:e46303. [PMID: 23029469 PMCID: PMC3460862 DOI: 10.1371/journal.pone.0046303] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 08/29/2012] [Indexed: 12/20/2022] Open
Abstract
Excessive production of endothelin-1 (ET-1), a potent vasoconstrictor, occurs with several forms of pulmonary hypertension. In addition to modulating vasomotor tone, ET-1 can potentiate pulmonary arterial smooth muscle cell (PASMC) growth and migration, both of which contribute to the vascular remodeling that occurs during the development of pulmonary hypertension. It is well established that changes in cell proliferation and migration in PASMCs are associated with alkalinization of intracellular pH (pHi), typically due to activation of Na+/H+ exchange (NHE). In the systemic vasculature, ET-1 increases pHi, Na+/H+ exchange activity and stimulates cell growth via a mechanism dependent on protein kinase C (PKC). These results, coupled with data describing elevated levels of ET-1 in hypertensive animals/humans, suggest that ET-1 may play an important role in modulating pHi and smooth muscle growth in the lung; however, the effect of ET-1 on basal pHi and NHE activity has yet to be examined in PASMCs. Thus, we used fluorescent microscopy in transiently (3–5 days) cultured rat PASMCs and the pH-sensitive dye, BCECF-AM, to measure changes in basal pHi and NHE activity induced by increasing concentrations of ET-1 (10−10 to 10−8 M). We found that application of exogenous ET-1 increased pHi and NHE activity in PASMCs and that the ET-1-induced augmentation of NHE was prevented in PASMCs pretreated with an inhibitor of Rho kinase, but not inhibitors of PKC. Moreover, direct activation of PKC had no effect on pHi or NHE activity in PASMCs. Our results indicate that ET-1 can modulate pH homeostasis in PASMCs via a signaling pathway that includes Rho kinase and that, in contrast to systemic vascular smooth muscle, activation of PKC does not appear to be an important regulator of PASMC pHi.
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MESH Headings
- Animals
- Cells, Cultured
- Dose-Response Relationship, Drug
- Endothelin-1/pharmacology
- Enzyme Activation/drug effects
- Fluoresceins
- Fluorescent Dyes
- Hydrogen-Ion Concentration
- Male
- Mice
- Mice, Inbred C57BL
- Microscopy, Fluorescence
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/enzymology
- Protein Kinase C/metabolism
- Protein Kinase Inhibitors/pharmacology
- Pulmonary Artery/cytology
- Pulmonary Artery/drug effects
- Pulmonary Artery/enzymology
- Signal Transduction/drug effects
- Sodium-Potassium-Exchanging ATPase/antagonists & inhibitors
- Sodium-Potassium-Exchanging ATPase/metabolism
- rho-Associated Kinases/antagonists & inhibitors
- rho-Associated Kinases/metabolism
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Affiliation(s)
- Clark Undem
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Eon J. Rios
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Julie Maylor
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Larissa A. Shimoda
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Iizuka M, Kimura K, Wang S, Kato K, Amano M, Kaibuchi K, Mizoguchi A. Distinct distribution and localization of Rho-kinase in mouse epithelial, muscle and neural tissues. Cell Struct Funct 2012; 37:155-75. [PMID: 22986902 DOI: 10.1247/csf.12018] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The small GTP-binding protein Rho plays a crucial role in a wide variety of cellular functions through various effector proteins. Rho-kinase is a key effector protein of Rho, which is composed of two isoforms, ROCK1 and ROCK2. To clarify the site of action of ROCK1 and ROCK2, we performed immunofluorescence and immunoelectron microscopic analyses using isoform-specific antibodies in mouse tissues. In the large and small intestines, ROCK1 immunoreactivity was predominantly identified in epithelial cells, and ROCK2 immunoreactivity was negligible. In these epithelial cells, ROCK1 immunoreactivity was distributed on plasma membranes, while ROCK1 immunogold signals were localized at cell-cell contacts and cell adhesion sites, especially at the adherens junctions at the ultrastructural level. In the bladder epithelium, however, ROCK1 and ROCK2 signals were identified at intermediate filaments, and ROCK2 signals were also observed in nuclei. In the three types of muscular cells-smooth, cardiac, and skeletal muscle cells-ROCK1 and ROCK2 also showed differential distribution. ROCK1 signals were localized at actin filaments, plasma membranes, and vesicles near plasma membranes in smooth muscle cells; at the lysosomes in skeletal muscle cells; and were undetectable in cardiac muscle cells. ROCK2 signals were localized at actin filaments and centrosomes in smooth muscle cells, at intercalated discs in cardiac muscle cells, and at Z-discs and sarcoplasmic reticulum in skeletal muscle cells. In the brain, ROCK1 immunoreactivity was distributed in glia, whereas ROCK2 immunoreactivity was observed in neurons. These results indicate that the two isoforms of Rho-kinase distribute differentially to accomplish their specific functions.
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Affiliation(s)
- Michiro Iizuka
- Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu, Japan
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44
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Fibronectin stimulates migration through lipid raft dependent NHE-1 activation in mouse embryonic stem cells: involvement of RhoA, Ca(2+)/CaM, and ERK. Biochim Biophys Acta Gen Subj 2012; 1820:1618-27. [PMID: 22683701 DOI: 10.1016/j.bbagen.2012.05.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 05/25/2012] [Accepted: 05/30/2012] [Indexed: 02/04/2023]
Abstract
BACKGROUND Extracellular matrix (ECM) components and intracellular pH (pH(i)) may serve as regulators of cell migration in various cell types. METHODS The Oris migration assay was used to assess the effect of fibronectin (FN) on cell motility. The Na(+)/H(+) exchanger (NHE)-1 activity was evaluated by measuring pH(i) and [(22)Na(+)] uptake. To examine activated signaling molecules, western blot analysis and immunoprecipitation was performed. RESULTS ECM components (FN, laminin, fibrinogen, and collagen type I) increased [(22)Na(+)] uptake, pH(i), and cell migration. In addition, FN-induced increase of cell migration was inhibited by NHE-1 inhibitor amiloride or NHE-1-specific siRNA. FN selectively increased the mRNA and protein expression of NHE-1, but not that of NHE-2 or NHE-3. FN binds integrin β1 and subsequently stimulates caveolin-1 phosphorylation and Ca(2+) influx. Then, NHE-1 is phosphorylated by RhoA and Rho kinases, and Ca(2+)/calmodulin (CaM) signaling elicits complex formation with NHE-1, which is enriched in lipid raft/caveolae microdomains of the plasma membrane. Activation of NHE-1 continuously induces an increase of [(22)Na(+)] uptake and pH(i). Finally, NHE-1-dependent extracellular signal-regulated kinase (ERK) 1/2 phosphorylation enhanced matrix metalloproteinase-2 (MMP-2) and filamentous-actin (F-actin) expression, partially contributing to the regulation of embryonic stem cells (ESCs) migration. CONCLUSIONS FN stimulated mESCs migration and proliferation through NHE-1 activation, which were mediated by lipid raft-associated caveolin-1, RhoA/ROCK, and Ca(2+)/CaM signaling pathways. GENERAL SIGNIFICANCE The precise role of NHE in the modulation of ECM-related physiological functions such as proliferation and migration remains poorly understood. Thus, this study analyzed the relationship between FN and NHE in regulating the migration of mouse ESCs and their related signaling pathways.
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45
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Jenkins EC, Debnath S, Gundry S, Gundry S, Uyar U, Fata JE. Intracellular pH regulation by Na+/H+ exchanger-1 (NHE1) is required for growth factor-induced mammary branching morphogenesis. Dev Biol 2012; 365:71-81. [DOI: 10.1016/j.ydbio.2012.02.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 01/30/2012] [Accepted: 02/09/2012] [Indexed: 01/19/2023]
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46
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Sit ST, Manser E. Rho GTPases and their role in organizing the actin cytoskeleton. J Cell Sci 2011; 124:679-83. [PMID: 21321325 DOI: 10.1242/jcs.064964] [Citation(s) in RCA: 352] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Soon-Tuck Sit
- sGSK Group, A-Star Neuroscience Research Partnership, Proteos Building, 61 Biopolis Drive, Singapore 138673, Singapore
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47
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Pakzad M, Totonchi M, Taei A, Seifinejad A, Hassani SN, Baharvand H. Presence of a ROCK inhibitor in extracellular matrix supports more undifferentiated growth of feeder-free human embryonic and induced pluripotent stem cells upon passaging. Stem Cell Rev Rep 2010; 6:96-107. [PMID: 20012714 DOI: 10.1007/s12015-009-9103-z] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Optimization and development of better defined culture methods for human embryonic and induced pluripotent stem cells (hESCs and hiPSCs) will provide an invaluable contribution to the field of regenerative medicine. However, one problem is the vulnerability of hESCs and hiPSCs to apoptosis that causes a low plating efficiency upon passaging. Herein, we have developed a novel hESCs and hiPSCs culture technique that uses ROCK inhibitor (ROCKi) Y-27632 (10 microM) in Matrigel-coated dishes in both serum- and feeder-free culture conditions. This increases plating efficiency during enzymatic and mechanical passaging as compared to its presence solely in culture medium. Under these conditions, hESCs (three lines) and hiPSCs (two lines) retain their typical morphology, a stable karyotype, express pluripotency markers and have the potential to differentiate into derivatives of all three germ layers after long-term culture. Real-time RT-PCR analysis of stemness-related integrins (alphaV, alpha6, and beta1) has demonstrated that their expression increases in the presence of ROCKi. Similar plating efficiencies have been obtained in both hESCs and hiPSCs with a lower concentration of Y-27632 (800 nM) and another ROCKi (HA-1077/Fasudil), thus ruling out the non-specific effects of Y-27632. These results show that addition of ROCKi in the extracellular matrix can increase the plating efficiency of hESCs and hiPSCs during passaging of clusters. This is due not only to an anti-apoptotic effect, but also to an increase in the ECM-cells interaction. Therefore, we believe this method will be useful for both current and future applications of these pluripotent stem cells.
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Affiliation(s)
- Mohammad Pakzad
- Department of Stem Cells and Developmental Biology, Royan Institute for Stem Cell Biology and Technology, ACECR, P.O. Box 19395-4644, Tehran, Iran
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48
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Casey JR, Grinstein S, Orlowski J. Sensors and regulators of intracellular pH. Nat Rev Mol Cell Biol 2009; 11:50-61. [PMID: 19997129 DOI: 10.1038/nrm2820] [Citation(s) in RCA: 1522] [Impact Index Per Article: 101.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Protons dictate the charge and structure of macromolecules and are used as energy currency by eukaryotic cells. The unique function of individual organelles therefore depends on the establishment and stringent maintenance of a distinct pH. This, in turn, requires a means to sense the prevailing pH and to respond to deviations from the norm with effective mechanisms to transport, produce or consume proton equivalents. A dynamic, finely tuned balance between proton-extruding and proton-importing processes underlies pH homeostasis not only in the cytosol, but in other cellular compartments as well.
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Affiliation(s)
- Joseph R Casey
- Departments of Physiology and Biochemistry, University of Alberta, Canada
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49
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Involvement of aquaporin in thromboxane A2 receptor-mediated, G 12/13/RhoA/NHE-sensitive cell swelling in 1321N1 human astrocytoma cells. Cell Signal 2009; 22:41-6. [PMID: 19772916 DOI: 10.1016/j.cellsig.2009.09.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 09/09/2009] [Indexed: 11/22/2022]
Abstract
The physiological role of the thromboxane A(2) (TXA(2)) receptor expressed on glial cells remains unclear. We previously reported that 1321N1 human astrocytoma cells pretreated with dibutyryl cyclic AMP (dbcAMP) became swollen in response to U46619, a TXA(2) analogue. In the present study, we examined the detailed mechanisms of TXA(2) receptor-mediated cell swelling in 1321N1 cells. The cell swelling caused by U46619 was suppressed by expression of p115-RGS, an inhibitory peptide of G alpha(12/13) pathway and C3 toxin, an inhibitory protein for RhoA. The swelling was also inhibited by treatment with Y27632, a Rho kinase inhibitor and 5-(ethyl-N-isopropyl)amiloride (EIPA), a Na(+)/H(+)-exchanger inhibitor. Furthermore, cell swelling was suppressed by the pretreatment with aquaporin inhibitors mercury chloride or phloretin in a concentration-dependent manner, suggesting that aquaporins are involved in U46619-induced 1321N1 cell swelling. In fact, U46619 caused [(3)H]H(2)O influx into the cells, which was inhibited by p115-RGS, C3 toxin, EIPA, mercury chloride and phloretin. This is the first report that the TXA(2) receptor mediates water influx through aquaporins in astrocytoma cells via TXA(2) receptor-mediated activation of G alpha(12/13), Rho A, Rho kinase and Na(+)/H(+)-exchanger.
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50
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Meima ME, Webb BA, Witkowska HE, Barber DL. The sodium-hydrogen exchanger NHE1 is an Akt substrate necessary for actin filament reorganization by growth factors. J Biol Chem 2009; 284:26666-75. [PMID: 19622752 DOI: 10.1074/jbc.m109.019448] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The kinase Akt mediates signals from growth factor receptors for increased cell proliferation, survival, and migration, which contribute to the positive effects of Akt in cancer progression. Substrates are generally inhibited when phosphorylated by Akt; however, we show phosphorylation of the plasma membrane sodium-hydrogen exchanger NHE1 by Akt increases exchanger activity (H(+) efflux). Our data fulfill criteria for NHE1 being a bona fide Akt substrate, including direct phosphorylation in vitro, using mass spectrometry and Akt phospho-substrate antibodies to identify Ser(648) as the Akt phosphorylation site and loss of increased exchanger phosphorylation and activity by insulin and platelet-derived growth factor in fibroblasts expressing a mutant NHE1-S648A. How Akt induces actin cytoskeleton remodeling to promote cell migration and tumor cell metastasis is unclear, but disassembly of actin stress fibers by platelet-derived growth factor and insulin and increased proliferation in growth medium are inhibited in fibroblasts expressing NHE1-S648A. We predict that other functions shared by Akt and NHE1, including cell growth and survival, might be regulated by increased H(+) efflux.
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Affiliation(s)
- Marcel E Meima
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143, USA
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