1
|
Domínguez-López A, Magaña-Guerrero FS, Buentello-Volante B, Vivanco-Rojas Ó, Garfias Y. NFAT5: a stress-related transcription factor with multiple functions in health and disease. Cell Stress 2025; 9:16-48. [PMID: 40421201 PMCID: PMC12105643 DOI: 10.15698/cst2025.05.304] [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: 12/13/2024] [Revised: 04/06/2025] [Accepted: 04/23/2025] [Indexed: 05/28/2025] Open
Abstract
Nuclear factor of activated T cells 5 (NFAT5) is a transcription factor within the Rel family, primarily recognized for its role in cellular adaptation to osmotic stress, particularly in hypertonic and hyperosmotic environments. Beyond osmotic regulation, NFAT5 responds to diverse stimuli, including cytokines, growth factors, oxidative stress, and microbial signals. This versatility enables NFAT5 to regulate essential cellular processes such as proliferation, survival, migration, and vascular remodelling. In the immune system, NFAT5 modulates the function of monocytes, macrophages, astrocytes, microglia, and T cells, contributing to immune homeostasis and inflammatory responses. Dysregulation of NFAT5 activity is implicated in various pathological conditions, including autoimmune diseases, cancer, and cardiovascular disorders, largely due to its ability to control genes involved in inflammatory and immune pathways under both isotonic and hypertonic conditions. Recent studies have unveiled new regulatory mechanisms, including interactions with non-coding RNAs, offering deeper insights into the functional landscape of NFAT5 and its therapeutic potential. This review delves into the multifaceted roles of NFAT5 in health and disease, emphasizing its emerging importance as a promising therapeutic target.
Collapse
Affiliation(s)
- Alfredo Domínguez-López
- Department of Biochemistry, Faculty of Medicine, Universidad Nacional Autónoma de México. Mexico City, Mexico. 04510
- Cell and Tissue Biology Department, Research Unit, Institute of Ophthalmology Conde de Valenciana. Mexico City, Mexico. 06800
| | - Fátima S. Magaña-Guerrero
- Cell and Tissue Biology Department, Research Unit, Institute of Ophthalmology Conde de Valenciana. Mexico City, Mexico. 06800
| | - Beatriz Buentello-Volante
- Cell and Tissue Biology Department, Research Unit, Institute of Ophthalmology Conde de Valenciana. Mexico City, Mexico. 06800
| | - Óscar Vivanco-Rojas
- Department of Biochemistry, Faculty of Medicine, Universidad Nacional Autónoma de México. Mexico City, Mexico. 04510
- Cell and Tissue Biology Department, Research Unit, Institute of Ophthalmology Conde de Valenciana. Mexico City, Mexico. 06800
| | - Yonathan Garfias
- Department of Biochemistry, Faculty of Medicine, Universidad Nacional Autónoma de México. Mexico City, Mexico. 04510
- Cell and Tissue Biology Department, Research Unit, Institute of Ophthalmology Conde de Valenciana. Mexico City, Mexico. 06800
| |
Collapse
|
2
|
Darwish T, Swaidan NT, Emara MM. Stress Factors as Possible Regulators of Pluripotent Stem Cell Survival and Differentiation. BIOLOGY 2023; 12:1119. [PMID: 37627003 PMCID: PMC10452095 DOI: 10.3390/biology12081119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/02/2023] [Accepted: 08/05/2023] [Indexed: 08/27/2023]
Abstract
In recent years, extensive research efforts have been directed toward pluripotent stem cells, primarily due to their remarkable capacity for pluripotency. This unique attribute empowers these cells to undergo self-renewal and differentiate into various cell types originating from the ectoderm, mesoderm, and endoderm germ layers. The delicate balance and precise regulation of self-renewal and differentiation are essential for the survival and functionality of these cells. Notably, exposure to specific environmental stressors can activate numerous transcription factors, initiating a diverse array of stress response pathways. These pathways play pivotal roles in regulating gene expression and protein synthesis, ultimately aiming to preserve cell survival and maintain cellular functions. Reactive oxygen species, heat shock, hypoxia, osmotic stress, DNA damage, endoplasmic reticulum stress, and mechanical stress are among the examples of such stressors. In this review, we comprehensively discuss the impact of environmental stressors on the growth of embryonic cells. Furthermore, we provide a summary of the distinct stress response pathways triggered when pluripotent stem cells are exposed to different environmental stressors. Additionally, we highlight recent discoveries regarding the role of such stressors in the generation, differentiation, and self-renewal of induced pluripotent stem cells.
Collapse
Affiliation(s)
| | | | - Mohamed M. Emara
- Basic Medical Sciences Department, College of Medicine, QU Health, Qatar University, 2713 Doha, Qatar
| |
Collapse
|
3
|
Chowdhury MAR, An J, Jeong S. The Pleiotropic Face of CREB Family Transcription Factors. Mol Cells 2023; 46:399-413. [PMID: 37013623 PMCID: PMC10336275 DOI: 10.14348/molcells.2023.2193] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/03/2023] [Accepted: 02/07/2023] [Indexed: 04/05/2023] Open
Abstract
cAMP responsive element-binding protein (CREB) is one of the most intensively studied phosphorylation-dependent transcription factors that provide evolutionarily conserved mechanisms of differential gene expression in vertebrates and invertebrates. Many cellular protein kinases that function downstream of distinct cell surface receptors are responsible for the activation of CREB. Upon functional dimerization of the activated CREB to cis-acting cAMP responsive elements within the promoters of target genes, it facilitates signal-dependent gene expression. From the discovery of CREB, which is ubiquitously expressed, it has been proven to be involved in a variety of cellular processes that include cell proliferation, adaptation, survival, differentiation, and physiology, through the control of target gene expression. In this review, we highlight the essential roles of CREB proteins in the nervous system, the immune system, cancer development, hepatic physiology, and cardiovascular function and further discuss a wide range of CREB-associated diseases and molecular mechanisms underlying the pathogenesis of these diseases.
Collapse
Affiliation(s)
- Md. Arifur Rahman Chowdhury
- Division of Life Sciences (Molecular Biology Major), Department of Bioactive Material Sciences, and Research Center of Bioactive Materials, Jeonbuk National University, Jeonju 54896, Korea
| | - Jungeun An
- Division of Life Sciences (Life Sciences Major), Jeonbuk National University, Jeonju 54896, Korea
| | - Sangyun Jeong
- Division of Life Sciences (Molecular Biology Major), Department of Bioactive Material Sciences, and Research Center of Bioactive Materials, Jeonbuk National University, Jeonju 54896, Korea
| |
Collapse
|
4
|
Svec KV, Howe AK. Protein Kinase A in cellular migration-Niche signaling of a ubiquitous kinase. Front Mol Biosci 2022; 9:953093. [PMID: 35959460 PMCID: PMC9361040 DOI: 10.3389/fmolb.2022.953093] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 06/30/2022] [Indexed: 12/28/2022] Open
Abstract
Cell migration requires establishment and maintenance of directional polarity, which in turn requires spatial heterogeneity in the regulation of protrusion, retraction, and adhesion. Thus, the signaling proteins that regulate these various structural processes must also be distinctly regulated in subcellular space. Protein Kinase A (PKA) is a ubiquitous serine/threonine kinase involved in innumerable cellular processes. In the context of cell migration, it has a paradoxical role in that global inhibition or activation of PKA inhibits migration. It follows, then, that the subcellular regulation of PKA is key to bringing its proper permissive and restrictive functions to the correct parts of the cell. Proper subcellular regulation of PKA controls not only when and where it is active but also specifies the targets for that activity, allowing the cell to use a single, promiscuous kinase to exert distinct functions within different subcellular niches to facilitate cell movement. In this way, understanding PKA signaling in migration is a study in context and in the elegant coordination of distinct functions of a single protein in a complex cellular process.
Collapse
Affiliation(s)
- Kathryn V. Svec
- Department of Pharmacology, University of Vermont, Burlington, VT, United States
| | - Alan K. Howe
- Department of Pharmacology, University of Vermont, Burlington, VT, United States
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, V T, United States
- University of Vermont Cancer Center, University of Vermont, Burlington, VT, United States
| |
Collapse
|
5
|
Johnson RJ, García-Arroyo FE, Gonzaga-Sánchez G, Vélez-Orozco KA, Álvarez-Álvarez YQ, Aparicio-Trejo OE, Tapia E, Osorio-Alonso H, Andrés-Hernando A, Nakagawa T, Kuwabara M, Kanbay M, Lanaspa MA, Sánchez-Lozada LG. Current Hydration Habits: The Disregarded Factor for the Development of Renal and Cardiometabolic Diseases. Nutrients 2022; 14:2070. [PMID: 35631211 PMCID: PMC9145744 DOI: 10.3390/nu14102070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 01/21/2023] Open
Abstract
Improper hydration habits are commonly disregarded as a risk factor for the development of chronic diseases. Consuming an intake of water below recommendations (underhydration) in addition to the substitution of sugar-sweetened beverages (SSB) for water are habits deeply ingrained in several countries. This behavior is due to voluntary and involuntary dehydration; and because young children are exposed to SSB, the preference for a sweet taste is profoundly implanted in the brain. Underhydration and SSB intake lead to mild hyperosmolarity, which stimulates biologic processes, such as the stimulation of vasopressin and the polyol-fructose pathway, which restore osmolarity to normal but at the expense of the continued activation of these biological systems. Unfortunately, chronic activation of the vasopressin and polyol-fructose pathways has been shown to mediate many diseases, such as obesity, diabetes, metabolic syndrome, chronic kidney disease, and cardiovascular disease. It is therefore urgent that we encourage educational and promotional campaigns that promote the evaluation of personal hydration status, a greater intake of potable water, and a reduction or complete halting of the drinking of SSB.
Collapse
Affiliation(s)
- Richard J. Johnson
- Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA;
| | - Fernando E. García-Arroyo
- Department Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (G.G.-S.); (K.A.V.-O.); (Y.Q.Á.-Á.); (O.E.A.-T.); (E.T.); (H.O.-A.)
| | - Guillermo Gonzaga-Sánchez
- Department Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (G.G.-S.); (K.A.V.-O.); (Y.Q.Á.-Á.); (O.E.A.-T.); (E.T.); (H.O.-A.)
| | - Kevin A. Vélez-Orozco
- Department Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (G.G.-S.); (K.A.V.-O.); (Y.Q.Á.-Á.); (O.E.A.-T.); (E.T.); (H.O.-A.)
| | - Yamnia Quetzal Álvarez-Álvarez
- Department Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (G.G.-S.); (K.A.V.-O.); (Y.Q.Á.-Á.); (O.E.A.-T.); (E.T.); (H.O.-A.)
| | - Omar Emiliano Aparicio-Trejo
- Department Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (G.G.-S.); (K.A.V.-O.); (Y.Q.Á.-Á.); (O.E.A.-T.); (E.T.); (H.O.-A.)
| | - Edilia Tapia
- Department Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (G.G.-S.); (K.A.V.-O.); (Y.Q.Á.-Á.); (O.E.A.-T.); (E.T.); (H.O.-A.)
| | - Horacio Osorio-Alonso
- Department Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (G.G.-S.); (K.A.V.-O.); (Y.Q.Á.-Á.); (O.E.A.-T.); (E.T.); (H.O.-A.)
| | - Ana Andrés-Hernando
- Division of Nephrology and Hypertension, Oregon Health Sciences University, Portland, OR 97239, USA; (A.A.-H.); (M.A.L.)
| | - Takahiko Nakagawa
- Department of Nephrology, Rakuwakai Otowa Hospital, Kyoto 607-8062, Japan;
| | - Masanari Kuwabara
- Intensive Care Unit, Toranomon Hospital, Tokyo 105-8470, Japan;
- Department of Cardiology, Toranomon Hospital, Tokyo 105-8470, Japan
| | - Mehmet Kanbay
- Division of Nephrology, Department of Internal Medicine, Koc University School of Medicine, Istanbul 34010, Turkey;
| | - Miguel A. Lanaspa
- Division of Nephrology and Hypertension, Oregon Health Sciences University, Portland, OR 97239, USA; (A.A.-H.); (M.A.L.)
| | - Laura Gabriela Sánchez-Lozada
- Department Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (G.G.-S.); (K.A.V.-O.); (Y.Q.Á.-Á.); (O.E.A.-T.); (E.T.); (H.O.-A.)
| |
Collapse
|
6
|
Peña-Münzenmayer G, Kondo Y, Salinas C, Sarmiento J, Brauchi S, Catalán MA. Activation of the Ae4 (Slc4a9) cation-driven Cl -/HCO 3- exchanger by the cAMP-dependent protein kinase in salivary gland acinar cells. Am J Physiol Gastrointest Liver Physiol 2021; 321:G628-G638. [PMID: 34585968 PMCID: PMC8887885 DOI: 10.1152/ajpgi.00145.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 09/24/2021] [Accepted: 09/27/2021] [Indexed: 01/31/2023]
Abstract
Ae4 transporters are critical for Cl- uptake across the basolateral membrane of acinar cells in the submandibular gland (SMG). Although required for fluid secretion, little is known about the physiological regulation of Ae4. To investigate whether Ae4 is regulated by the cAMP-dependent signaling pathway, we measured Cl-/HCO3- exchanger activity in SMG acinar cells from Ae2-/- mice, which only express Ae4, and found that the Ae4-mediated activity was increased in response to β-adrenergic receptor stimulation. Moreover, pretreatment with H89, an inhibitor of the cAMP-activated kinase (PKA), prevented the stimulation of Ae4 exchangers. We then expressed Ae4 in CHO-K1 cells and found that the Ae4-mediated activity was increased when Ae4 is coexpressed with the catalytic subunit of PKA (PKAc), which is constitutively active. Ae4 sequence analysis showed two potential PKA phosphorylation serine residues located at the intracellular NH2-terminal domain according to a homology model of Ae4. NH2-terminal domain Ser residues were mutated to alanine (S173A and S273A, respectively), where the Cl-/HCO3- exchanger activity displayed by the mutant S173A was not activated by PKA. Conversely, S273A mutant kept the PKA dependency. Together, we conclude that Ae4 is stimulated by PKA in SMG acinar cells by a mechanism that probably depends on the phosphorylation of S173.NEW & NOTEWORTHY We found that Ae4 exchanger activity in secretory salivary gland acinar cells is increased upon β-adrenergic receptor stimulation. The activation of Ae4 was prevented by H89, a nonselective PKA inhibitor. Protein sequence analysis revealed two residues (S173 and S273) that are potential targets of cAMP-dependent protein kinase (PKA). Experiments in CHO-K1 cells expressing S173A and S273A mutants showed that S173A, but not S273A, is not activated by PKA.
Collapse
Affiliation(s)
- Gaspar Peña-Münzenmayer
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile
| | - Yusuke Kondo
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Fukuoka, Japan
| | - Constanza Salinas
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
| | - José Sarmiento
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
| | - Sebastián Brauchi
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile
| | - Marcelo A Catalán
- Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
| |
Collapse
|
7
|
NFAT5 directs hyperosmotic stress-induced fibrin deposition and macrophage infiltration via PAI-1 in endothelium. Aging (Albany NY) 2020; 13:3661-3679. [PMID: 33410782 PMCID: PMC7906158 DOI: 10.18632/aging.202330] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 10/31/2020] [Indexed: 12/12/2022]
Abstract
Although stress can significantly promote atherosclerosis, the underlying mechanisms are still not completely understood. Here we successfully unveiled that high salt-induced nuclear factor of activated T cells 5 (NFAT5) control the endothelial-dependent fibrinolytic activity and the inflammatory adhesion-related molecules expression through regulation of plasminogen activator inhibitor-1 (PAI-1). We first observed that high salt diets instigated the expression of NFAT5 and PAI-1 in the endothelium which brought about the fibrin deposition and macrophage infiltration in the atherosclerotic arteries of ApoE-/- mice. Overexpression of NFAT5 increased PAI-1-mediated antifibrinolytic activity and activated inflammatory adhesion-related genes in endothelial cells. Knockdown of NFAT5 by siRNA inhibited the expression of PAI-1, antifibrinolytic and adhesive molecules. Moreover, chromatin immunoprecipitation assay demonstrated that high salt intake significantly promoted the binding of NFAT5 to PAI-1 promoter (TGGAATTATTT) in endothelial cells. Our study identified that NFAT5 has great potential to activate the PAI-1-mediated fibrinolytic dysfunction and inflammatory cell adhesion, thus promoting high salt-induced atherosclerosis disease.
Collapse
|
8
|
Su M, Zhang R, Liu N, Zhang J. Modulation of inflammatory response by cortisol in the kidney of spotted scat (Scatophagus argus) in vitro under different osmotic stresses. FISH & SHELLFISH IMMUNOLOGY 2020; 104:46-54. [PMID: 32474084 DOI: 10.1016/j.fsi.2020.05.060] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 05/20/2020] [Accepted: 05/23/2020] [Indexed: 06/11/2023]
Abstract
Salinity changes on renal osmoregulation have often been investigated while the immune response of the kidney under osmotic stress is poorly understood in teleosts. Acute stress is generally associated with enhancement of circulating cortisol. The effects of osmotic stress on renal immune response and its regulation by cortisol deserve more attention. In the present study, the effects of exogenous cortisol treatment on the lipopolysaccharide (LPS)-induced immune response were analyzed in renal masses of Scatophagus argus under different osmotic stresses in vitro. mRNA expression of pro-inflammatory cytokines (TNF-α, IL1-β and IL-6) and immune-regulatory related genes (GR and SOCS1) was measured over a short course (15 h). Comprehensive analysis reveals that transcript abundances of pro-inflammatory cytokine genes such as TNF-α, IL-1β, and IL-6 induced by LPS, alone or in the combination of cortisol, are tightly associated with osmoregulation under acute osmotic stress. Our results showed that osmotic challenge could significantly enhance mRNA expression levels of pro-inflammatory cytokines in renal masses in vitro. Based on our analysis, it can be inferred that cortisol suppresses the magnitude of renal inflammatory response and attenuates LPS-induced immune response through GR signaling in the face of challenging environmental conditions.
Collapse
Affiliation(s)
- Maoliang Su
- Shenzhen Key Laboratory of Marine Bioresource & Eco-Environmental Science, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China; Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Ran Zhang
- Shenzhen Key Laboratory of Marine Bioresource & Eco-Environmental Science, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China; Department of Physical and Environmental Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Nanxi Liu
- Shenzhen Key Laboratory of Marine Bioresource & Eco-Environmental Science, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
| | - Junbin Zhang
- Shenzhen Key Laboratory of Marine Bioresource & Eco-Environmental Science, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China.
| |
Collapse
|
9
|
García-Arroyo FE, Muñoz-Jiménez I, Gonzaga G, Tapia E, Osorio-Alonso H, Roncal-Jiménez CA, Iroz A, Vecchio M, Reyes-García JG, Johnson RJ, Sánchez-Lozada LG. A Role for Both V1a and V2 Receptors in Renal Heat Stress Injury Amplified by Rehydration with Fructose. Int J Mol Sci 2019; 20:ijms20225764. [PMID: 31744099 PMCID: PMC6888540 DOI: 10.3390/ijms20225764] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/10/2019] [Accepted: 11/14/2019] [Indexed: 01/17/2023] Open
Abstract
Chronic vasopressin secretion induced by recurrent mild heat stress exposure is significantly enhanced by limited rehydration with a fructose-containing beverage both in rodents and in humans. Moreover, this effect has been associated with upregulation of the polyol–fructokinase pathway and increased renal oxidative stress. Previously, we have shown that pharmacological inhibition of both V1a and V2 vasopressin receptors with conivaptan improved such renal alterations. The aim of this study was to evaluate the independent contributions of V1a and V2 receptors to the renal damage caused by mild heat stress and limited rehydration with a fructose-containing beverage. Osmotic minipumps were used to deliver either relcovaptan (0.64 mg/day) or tolvaptan (0.25 mg/day) in male Wistar rats for two weeks. Corresponding dilution vehicles were used as controls. To induce dehydration, rats were exposed to mild heat stress (37 °C for 1 h, Monday to Friday). All groups received a 10% fructose solution as a rehydration fluid for 2 h after mild heat stress. For the remainder of the day and on weekends, rats received tap water. The independent blockade of either the V1a or the V2 receptor prevented renal damage, reduced oxidative stress, and decreased plasma cortisol and systemic inflammation. However, the beneficial effects were regulated by different mechanisms. Tolvaptan inhibited polyol–fructokinase pathway overactivation, while relcovaptan prevented upregulation of the renin–angiotensin system and SGK1 expression. These data suggest that both V1a and V2 receptors participate in renal damage caused by heat stress-induced dehydration when fructose-containing beverages are used as rehydration fluids.
Collapse
Affiliation(s)
- Fernando E. García-Arroyo
- Department of Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (I.M.-J.); (G.G.); (E.T.); (H.O.-A.)
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, IPN Mexico City 11340, Mexico;
| | - Itzel Muñoz-Jiménez
- Department of Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (I.M.-J.); (G.G.); (E.T.); (H.O.-A.)
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, IPN Mexico City 11340, Mexico;
| | - Guillermo Gonzaga
- Department of Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (I.M.-J.); (G.G.); (E.T.); (H.O.-A.)
| | - Edilia Tapia
- Department of Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (I.M.-J.); (G.G.); (E.T.); (H.O.-A.)
| | - Horacio Osorio-Alonso
- Department of Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (I.M.-J.); (G.G.); (E.T.); (H.O.-A.)
| | - Carlos A Roncal-Jiménez
- Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (C.A.R.-J.); (R.J.J.)
| | - Alison Iroz
- Danone Research, 91767 Palaiseau, France; (A.I.); (M.V.)
| | | | - Juan G. Reyes-García
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, IPN Mexico City 11340, Mexico;
| | - Richard J Johnson
- Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (C.A.R.-J.); (R.J.J.)
| | - L Gabriela Sánchez-Lozada
- Department of Cardio-Renal Physiopathology, INC Ignacio Chávez, Mexico City 14080, Mexico; (F.E.G.-A.); (I.M.-J.); (G.G.); (E.T.); (H.O.-A.)
- Correspondence: or
| |
Collapse
|
10
|
Ma P, Zha S, Shen X, Zhao Y, Li L, Yang L, Lei M, Liu W. NFAT5 mediates hypertonic stress-induced atherosclerosis via activating NLRP3 inflammasome in endothelium. Cell Commun Signal 2019; 17:102. [PMID: 31429763 PMCID: PMC6701070 DOI: 10.1186/s12964-019-0406-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 07/28/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND How high-salt intake leads to the occurrence of many cardiovascular diseases such as atherosclerosis is a fundamental question in pathology. Here we postulated that high-salt-induced NFAT5 controls the inflammasome activation by directly regulating NLRP3, which mediates the expression of inflammatory- and adhesion-related genes in vascular endothelium, resulting in the formation of atherosclerosis. METHODS Atherosclerosis-prone apolipoprotein E-deficient (ApoE-/-) mice which accumulate cholesterol ester-enriched particles in the blood due to poor lipoprotein clearance capacity were used as the atherosclerosis model in vivo. Cultured endothelial cells (ECs) and monocytes under high-salt condition were used to explore the atheroprone role of the activation of NFAT5-NLRP3 inflammasome in vascular endothelium in vitro. Bioinformatic analysis and chromatin immunoprecipitation assay were used to identify the DNA binding sites of NFAT5 on promoters of NLRP3 and IL-1β. RESULTS We first observe that high-salt intake promotes atherosclerosis formation in the aortas of ApoE-/- mice, through inducing the expression of NFAT5, NLRP3, and IL-1β in endothelium. Overexpression of NFAT5 activates NLRP3-inflammasome and increases the secretion of IL-1β in ECs partly via ROS. Chromatin immunoprecipitation assay demonstrates that NFAT5 directly binds to the promoter regions of NLRP3 and IL-1β in endothelial cells subjected to the high-salt environment. CONCLUSIONS Our study identifies NFAT5 as a new and essential transcription factor that is required for the early activation of NLRP3-inflammasome-mediated endothelium innate immunity, contributing to the formation of atherosclerosis under hypertonic stress induction.
Collapse
Affiliation(s)
- Pingping Ma
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, China
| | - Shenfang Zha
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, China
| | - Xinkun Shen
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, China
| | - Yulan Zhao
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, China
| | - Li Li
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, China
| | - Li Yang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, China
| | - Mingxing Lei
- Integrative Stem Cell Center, China Medical University Hospital, China Medical University, Taichung, 40402, Taiwan. .,Institute of New Drug Development, College of Biopharmaceutical and Food Sciences, China Medical University, Taichung, 40402, Taiwan.
| | - Wanqian Liu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, China.
| |
Collapse
|
11
|
Wang H, Morris RG, Knepper MA, Zhou X. Sickle cell disease up-regulates vasopressin, aquaporin 2, urea transporter A1, Na-K-Cl cotransporter 2, and epithelial Na channels in the mouse kidney medulla despite compromising urinary concentration ability. Physiol Rep 2019; 7:e14066. [PMID: 31033226 PMCID: PMC6487471 DOI: 10.14814/phy2.14066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 03/18/2019] [Accepted: 03/29/2019] [Indexed: 11/24/2022] Open
Abstract
Sickle cell disease (SCD)-induced urinary concentration defect has been proposed as caused by impaired ability of the occluded vasa recta due to red blood cell sickling to serve as countercurrent exchangers and renal tubules to absorb water and solutes. However, the exact molecular mechanisms remain largely unknown. The present studies were undertaken to determine the effects of SCD on vasopressin, aquaporin2 (AQP2), urea transporter A1 (UTA1), Na-K-Cl co-transporter 2 (NKCC2), epithelial Na channels (ENaC), aquaporin1 (AQP1), nuclear factor of activated T cells 5 (NFAT5) and Src homology region-2 domain-containing phosphatase-1 (SHP-1), an important regulator of NFAT5, in the Berkeley SCD mouse kidney medulla. Under water repletion, SCD only induced a minor urinary concentration defect associated with increased urinary vasopressin level alone with the well-known effects of vasopressin: protein abundance of AQP2, UTA1 and ENaC-β and apical targeting of AQP2 as compared with non-SCD. SCD did not significantly affect AQP1 protein level. Water restriction had no further significant effect on SCD urinary vasopressin. NFAT5 is also critical to urinary concentration. Instead, water restriction-activated NFAT5 associated with inhibition of SHP-1 in the SCD mice. Yet, water restriction only elevated urinary osmolality by 28% in these mice as opposed to 104% in non-SCD mice despite similar degree increases of protein abundance of AQP2, NKCC2 and AQP2-S256-P. Water-restriction had no significant effect on protein abundance of ENaC or AQP1 in either strain. In conclusion, under water repletion SCD, only induces a minor defect in urinary concentration because of compensation from the up-regulated vasopressin system. However, under water restriction, SCD mice struggle to concentrate urine despite activating NFAT5. SCD-induced urinary concentration defect appears to be resulted from the poor blood flow in vasa recta rather than the renal tubules' ability to absorb water and solutes.
Collapse
Affiliation(s)
- Hong Wang
- Department of MedicineUniformed Services University of Health SciencesBethesdaMaryland
| | | | | | - Xiaoming Zhou
- Department of MedicineUniformed Services University of Health SciencesBethesdaMaryland
| |
Collapse
|
12
|
Yang Z, Zhou J, Wei B, Cheng Y, Zhang L, Zhen X. Comparative transcriptome analysis reveals osmotic-regulated genes in the gill of Chinese mitten crab (Eriocheir sinensis). PLoS One 2019; 14:e0210469. [PMID: 30629688 PMCID: PMC6328174 DOI: 10.1371/journal.pone.0210469] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 12/24/2018] [Indexed: 11/19/2022] Open
Abstract
Salinity is one of the most important abiotic factors directly affecting the reproduction, molting, growth, immune, physiological and metabolic activities of Chinese mitten crab (Eriocheir sinensis). This species has strong osmoregulatory capacity and can maintain stringent internal homeostasis. However, the mechanisms conferring tolerance to salinity fluctuations are not well understood. To reveal the genes and pathways involved in osmoregulation, adult male crabs (body weight = 110 ± 5 g) were acclimated for 144 h in freshwater (FW, 0 ppt) or seawater (SW, 25 ppt). Changes in the transcriptome of crab gills were then analysed by RNA-Seq, and 174,903 unigenes were obtained. Comparison of genes between FW- SW-acclimated groups identified 932 genes that were significantly differentially expressed in the gill, comprising 433 and 499 up- and downregulated transcripts. Gene Ontology functional enrichment analysis revealed that important biological processes related to salt stress were significantly enriched, including energy metabolism, ion transport, signal transduction and antioxidant activity. Kyoto Encyclopaedia of Genes and Genomes enrichment analysis mapped the differentially expressed genes to 241 specific metabolic pathways, and pathways related to energy metabolism, oxidative phosphorylation and the tricarboxylic acid (TCA)/citrate cycle were significantly enriched. Salinity stress altered the expression of many enzymes involved in energy metabolism, ion transport, signal transduction and antioxidant pathways, including citrate synthase (CS), Na+/K+-ATPase (NKA), Na+-K+-2Cl cotransporter-1 (NKCC1), dopamine receptor D1 (DRD1), synaptic binding protein 1 (STXBP1), Cu2+/Zn2+ superoxide dismutase (SOD1) and glutathione S-transferase (GST). Additionally, the obtained transcriptomic sequencing data provided a useful resource for identification of novel genes, and further physiological analysis of Chinese mitten crab.
Collapse
Affiliation(s)
- Zhigang Yang
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- Centre for Research on Environmental Ecology and Fish Nutrition (CREEFN) of the Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
- * E-mail: (ZGY); (YXC)
| | - Junyu Zhou
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- Centre for Research on Environmental Ecology and Fish Nutrition (CREEFN) of the Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Banghong Wei
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- Centre for Research on Environmental Ecology and Fish Nutrition (CREEFN) of the Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Yongxu Cheng
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- Centre for Research on Environmental Ecology and Fish Nutrition (CREEFN) of the Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
- * E-mail: (ZGY); (YXC)
| | - Long Zhang
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- Centre for Research on Environmental Ecology and Fish Nutrition (CREEFN) of the Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Xiaomin Zhen
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- Centre for Research on Environmental Ecology and Fish Nutrition (CREEFN) of the Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| |
Collapse
|
13
|
Bátori R, Kumar S, Bordán Z, Cherian-Shaw M, Kovács-Kása A, MacDonald JA, Fulton DJR, Erdődi F, Verin AD. Differential mechanisms of adenosine- and ATPγS-induced microvascular endothelial barrier strengthening. J Cell Physiol 2018; 234:5863-5879. [PMID: 29271489 DOI: 10.1002/jcp.26419] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/18/2017] [Indexed: 12/11/2022]
Abstract
Maintenance of the endothelial cell (EC) barrier is critical to vascular homeostasis and a loss of barrier integrity results in increased vascular permeability. While the mechanisms that govern increased EC permeability have been under intense investigation over the past several decades, the processes regulating the preservation/restoration of the EC barrier remain poorly understood. Herein we show that the extracellular purines, adenosine (Ado) and adenosine 5'-[γ-thio]-triphosphate (ATPγS) can strengthen the barrier function of human lung microvascular EC (HLMVEC). This ability involves protein kinase A (PKA) activation and decreases in myosin light chain 20 (MLC20) phosphorylation secondary to the involvement of MLC phosphatase (MLCP). In contrast to Ado, ATPγS-induced PKA activation is accompanied by a modest, but significant decrease in cyclic adenosine monophosphate (cAMP) levels supporting the existence of an unconventional cAMP-independent pathway of PKA activation. Furthermore, ATPγS-induced EC barrier strengthening does not involve the Rap guanine nucleotide exchange factor 3 (EPAC1) which is directly activated by cAMP but is instead dependent upon PKA-anchor protein 2 (AKAP2) expression. We also found that AKAP2 can directly interact with the myosin phosphatase-targeting protein MYPT1 and that depletion of AKAP2 abolished ATPγS-induced increases in transendothelial electrical resistance. Ado-induced strengthening of the HLMVEC barrier required the coordinated activation of PKA and EPAC1 in a cAMP-dependent manner. In summary, ATPγS-induced enhancement of the EC barrier is EPAC1-independent and is instead mediated by activation of PKA which is then guided by AKAP2, in a cAMP-independent mechanism, to activate MLCP which dephosphorylates MLC20 resulting in reduced EC contraction and preservation.
Collapse
Affiliation(s)
- Róbert Bátori
- Vascular Biology Center, Augusta University, Augusta, Georgia
| | - Sanjiv Kumar
- Vascular Biology Center, Augusta University, Augusta, Georgia
| | | | | | | | - Justin A MacDonald
- Department of Biochemistry & Molecular Biology, Smooth Muscle Research Group, University of Calgary, Calgary, Alberta, Canada
| | - David J R Fulton
- Vascular Biology Center, Augusta University, Augusta, Georgia.,Department of Pharmacology, Augusta University, Augusta, Georgia
| | - Ferenc Erdődi
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,MTA-DE Cell Biology and Signalling Research Group, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Alexander D Verin
- Vascular Biology Center, Augusta University, Augusta, Georgia.,Department of Medicine, Augusta University, Augusta, Georgia
| |
Collapse
|
14
|
Glucose deprivation activates a cAMP-independent protein kinase from Trypanosoma equiperdum. Parasitology 2018; 146:643-652. [PMID: 30419978 DOI: 10.1017/s0031182018001920] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Kemptide (sequence: LRRASLG) is a synthetic peptide holding the consensus recognition site for the catalytic subunit of the cAMP-dependent protein kinase (PKA). cAMP-independent protein kinases that phosphorylate kemptide were stimulated in Trypanosoma equiperdum following glucose deprivation. An enriched kemptide kinase-containing fraction was isolated from glucose-starved parasites using sedimentation throughout a sucrose gradient, followed by sequential chromatography on diethylaminoethyl-Sepharose and Sephacryl S-300. The trypanosome protein possesses a molecular mass of 39.07-51.73 kDa, a Stokes radius of 27.4 Ǻ, a sedimentation coefficient of 4.06 S and a globular shape with a frictional ratio f/fo = 1.22-1.25. Optimal enzymatic activity was achieved at 37 °C and pH 8.0, and kinetic studies showed Km values for ATP and kemptide of 11.8 ± 4.1 and 24.7 ± 3.8 µm, respectively. The parasite enzyme uses ATP and Mg2+ and was inhibited by other nucleotides and/or analogues of ATP, such as cAMP, AMP, ADP, GMP, GDP, GTP, CTP, β,γ-imidoadenosine 5'-triphosphate and 5'-[p-(fluorosulfonyl)benzoyl] adenosine, and by other divalent cations, such as Zn2+, Mn2+, Co2+, Cu2+, Ca2+ and Fe2+. Additionally, the trypanosome kinase was inhibited by the PKA-specific heat-stable peptide inhibitor PKI-α. This study is the first biochemical and enzymatic characterization of a protein kinase from T. equiperdum.
Collapse
|
15
|
Choi H, Chaiyamongkol W, Doolittle AC, Johnson ZI, Gogate SS, Schoepflin ZR, Shapiro IM, Risbud MV. COX-2 expression mediated by calcium-TonEBP signaling axis under hyperosmotic conditions serves osmoprotective function in nucleus pulposus cells. J Biol Chem 2018; 293:8969-8981. [PMID: 29700115 DOI: 10.1074/jbc.ra117.001167] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 04/10/2018] [Indexed: 11/06/2022] Open
Abstract
The nucleus pulposus (NP) of intervertebral discs experiences dynamic changes in tissue osmolarity because of diurnal loading of the spine. TonEBP/NFAT5 is a transcription factor that is critical in osmoregulation as well as survival of NP cells in the hyperosmotic milieu. The goal of this study was to investigate whether cyclooxygenase-2 (COX-2) expression is osmoresponsive and dependent on TonEBP, and whether it serves an osmoprotective role. NP cells up-regulated COX-2 expression in hyperosmotic media. The induction of COX-2 depended on elevation of intracellular calcium levels and p38 MAPK pathway, but independent of calcineurin signaling as well as MEK/ERK and JNK pathways. Under hyperosmotic conditions, both COX-2 mRNA stability and its proximal promoter activity were increased. The proximal COX-2 promoter (-1840/+123 bp) contained predicted binding sites for TonEBP, AP-1, NF-κB, and C/EBP-β. While COX-2 promoter activity was positively regulated by both AP-1 and NF-κB, AP-1 had no effect and NF-κB negatively regulated COX-2 protein levels under hyperosmotic conditions. On the other hand, TonEBP was necessary for both COX-2 promoter activity and protein up-regulation in response to hyperosmotic stimuli. Ex vivo disc organ culture studies using hypomorphic TonEBP+/- mice confirmed that TonEBP is required for hyperosmotic induction of COX-2. Importantly, the inhibition of COX-2 activity under hyperosmotic conditions resulted in decreased cell viability, suggesting that COX-2 plays a cytoprotective and homeostatic role in NP cells for their adaptation to dynamically loaded hyperosmotic niches.
Collapse
Affiliation(s)
- Hyowon Choi
- From the Department of Orthopaedic Surgery and Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Weera Chaiyamongkol
- From the Department of Orthopaedic Surgery and Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and.,Department of Orthopaedic Surgery, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand
| | - Alexandra C Doolittle
- From the Department of Orthopaedic Surgery and Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Zariel I Johnson
- From the Department of Orthopaedic Surgery and Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Shilpa S Gogate
- From the Department of Orthopaedic Surgery and Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Zachary R Schoepflin
- From the Department of Orthopaedic Surgery and Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Irving M Shapiro
- From the Department of Orthopaedic Surgery and Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Makarand V Risbud
- From the Department of Orthopaedic Surgery and Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| |
Collapse
|
16
|
Ghidinelli M, Poitelon Y, Shin YK, Ameroso D, Williamson C, Ferri C, Pellegatta M, Espino K, Mogha A, Monk K, Podini P, Taveggia C, Nave KA, Wrabetz L, Park HT, Feltri ML. Laminin 211 inhibits protein kinase A in Schwann cells to modulate neuregulin 1 type III-driven myelination. PLoS Biol 2017. [PMID: 28636612 PMCID: PMC5479503 DOI: 10.1371/journal.pbio.2001408] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Myelin is required for proper nervous system function. Schwann cells in developing nerves depend on extrinsic signals from the axon and from the extracellular matrix to first sort and ensheathe a single axon and then myelinate it. Neuregulin 1 type III (Nrg1III) and laminin α2β1γ1 (Lm211) are the key axonal and matrix signals, respectively, but how their signaling is integrated and if each molecule controls both axonal sorting and myelination is unclear. Here, we use a series of epistasis experiments to show that Lm211 modulates neuregulin signaling to ensure the correct timing and amount of myelination. Lm211 can inhibit Nrg1III by limiting protein kinase A (PKA) activation, which is required to initiate myelination. We provide evidence that excessive PKA activation amplifies promyelinating signals downstream of neuregulin, including direct activation of the neuregulin receptor ErbB2 and its effector Grb2-Associated Binder-1 (Gab1), thereby elevating the expression of the key transcription factors Oct6 and early growth response protein 2 (Egr2). The inhibitory effect of Lm211 is seen only in fibers of small caliber. These data may explain why hereditary neuropathies associated with decreased laminin function are characterized by focally thick and redundant myelin.
Collapse
Affiliation(s)
- Monica Ghidinelli
- Hunter James Kelly Research Institute, Department of Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, The State University of New York at Buffalo, Buffalo, New York, United States of America
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, DIBIT, Milano, Italy
- UniSR, Vita Salute San Raffaele University, Milan, Italy
| | - Yannick Poitelon
- Hunter James Kelly Research Institute, Department of Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, The State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Yoon Kyoung Shin
- Department of Physiology, Peripheral Neuropathy Research Center, Dong-A University Medical School, Busan, South Korea
| | - Dominique Ameroso
- Hunter James Kelly Research Institute, Department of Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, The State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Courtney Williamson
- Hunter James Kelly Research Institute, Department of Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, The State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Cinzia Ferri
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, DIBIT, Milano, Italy
| | - Marta Pellegatta
- Hunter James Kelly Research Institute, Department of Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, The State University of New York at Buffalo, Buffalo, New York, United States of America
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, DIBIT, Milano, Italy
- UniSR, Vita Salute San Raffaele University, Milan, Italy
| | - Kevin Espino
- Hunter James Kelly Research Institute, Department of Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, The State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Amit Mogha
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Kelly Monk
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Paola Podini
- Division of Neuroscience and INSPE, San Raffaele Scientific Institute, DIBIT, Milano, Italy
| | - Carla Taveggia
- Division of Neuroscience and INSPE, San Raffaele Scientific Institute, DIBIT, Milano, Italy
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Lawrence Wrabetz
- Hunter James Kelly Research Institute, Department of Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, The State University of New York at Buffalo, Buffalo, New York, United States of America
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, DIBIT, Milano, Italy
| | - Hwan Tae Park
- Department of Physiology, Peripheral Neuropathy Research Center, Dong-A University Medical School, Busan, South Korea
- * E-mail: (MLF); (HTP)
| | - Maria Laura Feltri
- Hunter James Kelly Research Institute, Department of Biochemistry and Neurology, Jacobs School of Medicine and Biomedical Sciences, The State University of New York at Buffalo, Buffalo, New York, United States of America
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, DIBIT, Milano, Italy
- * E-mail: (MLF); (HTP)
| |
Collapse
|
17
|
Hollborn M, Fischer S, Kuhrt H, Wiedemann P, Bringmann A, Kohen L. Osmotic regulation of NFAT5 expression in RPE cells: The involvement of purinergic receptor signaling. Mol Vis 2017; 23:116-130. [PMID: 28356704 PMCID: PMC5360457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 03/16/2017] [Indexed: 11/22/2022] Open
Abstract
PURPOSE Systemic hypertension is a risk factor for age-related neovascular retinal diseases. The major condition that induces hypertension is the intake of dietary salt (NaCl) resulting in increased extracellular osmolarity. High extracellular NaCl was has been shown to induce angiogenic factor production in RPE cells, in part via the transcriptional activity of nuclear factor of activated T cell 5 (NFAT5). Here, we determined the signaling pathways that mediate the osmotic expression of the NFAT5 gene in RPE cells. METHODS Cultured human RPE cells were stimulated with high (+100 mM) NaCl. Alterations in gene and protein expression were determined with real-time reverse transcriptase (RT)-PCR and western blot analysis, respectively. RESULTS NaCl-induced NFAT5 gene expression was fully inhibited by calcium chelation and blockers of inositol triphosphate (IP3) receptors and phospholipases C and A2. Blockers of phospholipases C and A2 also prevented the NaCl-induced increase of the cellular NFAT5 protein level. Inhibitors of multiple intracellular signaling transduction pathways and kinases, including p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun NH2-terminal kinase (JNK), phosphatidylinositol-3 kinase (PI3K), protein kinases A and C, Src tyrosine kinases, and calpains, as well as cyclooxygenase inhibitors, decreased the NaCl-induced expression of the NFAT5 gene. In addition, autocrine purinergic signaling mediated by a release of ATP and a nucleoside transporter-mediated release of adenosine, activation of P2X7, P2Y1, P2Y2, and adenosine A1 receptors, but not adenosine A2A receptors, is required for the full expression of the NFAT5 gene under hyperosmotic conditions. NaCl-induced NFAT5 gene expression is in part dependent on the activity of nuclear factor κB (NF-κB). The NaCl-induced expression of NFAT5 protein was prevented by inhibitors of phospholipases C and A2 and an inhibitor of NF-κB, but it was not prevented by a P2Y1 inhibitor. CONCLUSIONS The data suggest that in addition to calcium signaling and activation of inflammatory enzymes, autocrine/paracrine purinergic signaling contributes to the stimulatory effect of hyperosmotic stress on the expression of the NFAT5 gene in RPE cells. It is suggested that high intake of dietary salt induces RPE cell responses, which may contribute to age-related retinal diseases.
Collapse
Affiliation(s)
- Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Sarah Fischer
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Heidrun Kuhrt
- Paul Flechsig Institute of Brain Research, University of Leipzig Medical Faculty, Leipzig, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Leon Kohen
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany,Helios Klinikum Aue, Aue, Germany
| |
Collapse
|
18
|
Warcoin E, Clouzeau C, Brignole-Baudouin F, Baudouin C. Hyperosmolarité : effets intracellulaires et implication dans la sécheresse oculaire. J Fr Ophtalmol 2016; 39:641-51. [DOI: 10.1016/j.jfo.2016.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/27/2016] [Accepted: 07/27/2016] [Indexed: 11/26/2022]
|
19
|
Alberdi M, Iglesias M, Tejedor S, Merino R, López-Rodríguez C, Aramburu J. Context-dependent regulation of Th17-associated genes and IFNγ expression by the transcription factor NFAT5. Immunol Cell Biol 2016; 95:56-67. [PMID: 27479742 PMCID: PMC5215110 DOI: 10.1038/icb.2016.69] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 07/11/2016] [Accepted: 07/26/2016] [Indexed: 12/17/2022]
Abstract
Stress-activated transcription factors influence T-cell function in different physiopathologic contexts. NFAT5, a relative of nuclear factor κB and the calcineurin-activated NFATc transcription factors, protects mammalian cells from hyperosmotic stress caused by the elevation of extracellular sodium levels. In T cells exposed to hypernatremia, NFAT5 not only induces osmoprotective gene products but also cytokines and immune receptors, which raises the question of whether this factor could regulate other T-cell functions in osmostress-independent contexts. Here we have used mice with a conditional deletion of Nfat5 in mature T lymphocytes to explore osmostress-dependent and -independent functions of this factor. In vitro experiments with CD4 T cells stimulated in hyperosmotic medium showed that NFAT5 enhanced the expression of IL-2 and the Th17-associated gene products RORγt and IL-23R. By contrast, NFAT5-deficient CD4 T cells activated in vivo by anti-CD3 antibody exhibited a different activation profile and were skewed towards enhanced interferon γ (IFNγ) and IL-17 expression and attenuated Treg responses. Using a model of experimental colitis, we observed that mice lacking NFAT5 in T cells exhibited exacerbated intestinal colitis and enhanced expression of IFNγ in draining lymph nodes and colon. These results show that NFAT5 can modulate different T-cell responses depending on stress conditions and stimulatory context.
Collapse
Affiliation(s)
- Maria Alberdi
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Marcos Iglesias
- Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC CSIC-Universidad de Cantabria), Santander, Spain
| | - Sonia Tejedor
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Ramón Merino
- Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC CSIC-Universidad de Cantabria), Santander, Spain
| | | | - Jose Aramburu
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| |
Collapse
|
20
|
DuMond JF, Ramkissoon K, Zhang X, Izumi Y, Wang X, Eguchi K, Gao S, Mukoyama M, Burg MB, Ferraris JD. Peptide affinity analysis of proteins that bind to an unstructured NH2-terminal region of the osmoprotective transcription factor NFAT5. Physiol Genomics 2016; 48:290-305. [PMID: 26757802 DOI: 10.1152/physiolgenomics.00110.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/09/2016] [Indexed: 11/22/2022] Open
Abstract
NFAT5 is an osmoregulated transcription factor that particularly increases expression of genes involved in protection against hypertonicity. Transcription factors often contain unstructured regions that bind co-regulatory proteins that are crucial for their function. The NH2-terminal region of NFAT5 contains regions predicted to be intrinsically disordered. We used peptide aptamer-based affinity chromatography coupled with mass spectrometry to identify protein preys pulled down by one or more overlapping 20 amino acid peptide baits within a predicted NH2-terminal unstructured region of NFAT5. We identify a total of 467 unique protein preys that associate with at least one NH2-terminal peptide bait from NFAT5 in either cytoplasmic or nuclear extracts from HEK293 cells treated with elevated, normal, or reduced NaCl concentrations. Different sets of proteins are pulled down from nuclear vs. cytoplasmic extracts. We used GeneCards to ascertain known functions of the protein preys. The protein preys include many that were previously known, but also many novel ones. Consideration of the novel ones suggests many aspects of NFAT5 regulation, interaction and function that were not previously appreciated, for example, hypertonicity inhibits NFAT5 by sumoylating it and the NFAT5 protein preys include components of the CHTOP complex that desumoylate proteins, an action that should contribute to activation of NFAT5.
Collapse
Affiliation(s)
- Jenna F DuMond
- Systems Biology Center, Division of Intramural Research, National Heart, Lung and Blood Institute, Bethesda Maryland; and
| | - Kevin Ramkissoon
- Systems Biology Center, Division of Intramural Research, National Heart, Lung and Blood Institute, Bethesda Maryland; and
| | - Xue Zhang
- Systems Biology Center, Division of Intramural Research, National Heart, Lung and Blood Institute, Bethesda Maryland; and
| | - Yuichiro Izumi
- Systems Biology Center, Division of Intramural Research, National Heart, Lung and Blood Institute, Bethesda Maryland; and Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Xujing Wang
- Systems Biology Center, Division of Intramural Research, National Heart, Lung and Blood Institute, Bethesda Maryland; and
| | - Koji Eguchi
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Shouguo Gao
- Systems Biology Center, Division of Intramural Research, National Heart, Lung and Blood Institute, Bethesda Maryland; and
| | - Masashi Mukoyama
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Maurice B Burg
- Systems Biology Center, Division of Intramural Research, National Heart, Lung and Blood Institute, Bethesda Maryland; and
| | - Joan D Ferraris
- Systems Biology Center, Division of Intramural Research, National Heart, Lung and Blood Institute, Bethesda Maryland; and
| |
Collapse
|
21
|
Zhou X. How do kinases contribute to tonicity-dependent regulation of the transcription factor NFAT5? World J Nephrol 2016; 5:20-32. [PMID: 26788461 PMCID: PMC4707165 DOI: 10.5527/wjn.v5.i1.20] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 10/12/2015] [Accepted: 12/11/2015] [Indexed: 02/06/2023] Open
Abstract
NFAT5 plays a critical role in maintaining the renal functions. Its dis-regulation in the kidney leads to or is associated with certain renal diseases or disorders, most notably the urinary concentration defect. Hypertonicity, which the kidney medulla is normally exposed to, activates NFAT5 through phosphorylation of a signaling molecule or NFAT5 itself. Hypotonicity inhibits NFAT5 through a similar mechanism. More than a dozen of protein and lipid kinases have been identified to contribute to tonicity-dependent regulation of NFAT5. Hypertonicity activates NFAT5 by increasing its nuclear localization and transactivating activity in the early phase and protein abundance in the late phase. The known mechanism for inhibition of NFAT5 by hypotonicity is a decrease of nuclear NFAT5. The present article reviews the effect of each kinase on NFAT5 nuclear localization, transactivation and protein abundance, and the relationship among these kinases, if known. Cyclosporine A and tacrolimus suppress immune reactions by inhibiting the phosphatase calcineurin-dependent activation of NFAT1. It is hoped that this review would stimulate the interest to seek explanations from the NFAT5 regulatory pathways for certain clinical presentations and to explore novel therapeutic approaches based on the pathways. On the basic science front, this review raises two interesting questions. The first one is how these kinases can specifically signal to NFAT5 in the context of hypertonicity or hypotonicity, because they also regulate other cellular activities and even opposite activities in some cases. The second one is why these many kinases, some of which might have redundant functions, are needed to regulate NFAT5 activity. This review reiterates the concept of signaling through cooperation. Cells need these kinases working in a coordinated way to provide the signaling specificity that is lacking in the individual one. Redundancy in regulation of NFAT5 is a critical strategy for cells to maintain robustness against hypertonic or hypotonic stress.
Collapse
|
22
|
Timucin AC, Bodur C, Basaga H. SIRT1 contributes to aldose reductase expression through modulating NFAT5 under osmotic stress: In vitro and in silico insights. Cell Signal 2015; 27:2160-72. [PMID: 26297866 DOI: 10.1016/j.cellsig.2015.08.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 08/18/2015] [Indexed: 12/13/2022]
Abstract
So far, a myriad of molecules were characterized to modulate NFAT5 and its downstream targets. Among these NFAT5 modifiers, SIRT1 was proposed to have a promising role in NFAT5 dependent events, yet the exact underlying mechanism still remains obscure. Hence, the link between SIRT1 and NFAT5-aldose reductase (AR) axis under osmotic stress, was aimed to be delineated in this study. A unique osmotic stress model was generated and its mechanistic components were deciphered in U937 monocytes. In this model, AR expression and nuclear NFAT5 stabilization were revealed to be positively regulated by SIRT1 through utilization of pharmacological modulators. Overexpression and co-transfection studies of NFAT5 and SIRT1 further validated the contribution of SIRT1 to AR and NFAT5. The involvement of SIRT1 activity in these events was mediated via modification of DNA binding of NFAT5 to AR ORE region. Besides, NFAT5 and SIRT1 were also shown to co-immunoprecipitate under isosmotic conditions and this interaction was disrupted by osmotic stress. Further in silico experiments were conducted to investigate if SIRT1 directly targets NFAT5. In this regard, certain lysine residues of NFAT5, when kept deacetylated, were found to contribute to its DNA binding and SIRT1 was shown to directly bind K282 of NFAT5. Based on these in vitro and in silico findings, SIRT1 was identified, for the first time, as a novel positive regulator of NFAT5 dependent AR expression under osmotic stress in U937 monocytes.
Collapse
Affiliation(s)
- Ahmet Can Timucin
- Molecular Biology, Genetics and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, 34956, Orhanli, Tuzla, Istanbul, Turkey.
| | - Cagri Bodur
- Molecular Biology, Genetics and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, 34956, Orhanli, Tuzla, Istanbul, Turkey.
| | - Huveyda Basaga
- Molecular Biology, Genetics and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, 34956, Orhanli, Tuzla, Istanbul, Turkey.
| |
Collapse
|
23
|
Watson RL, Buck J, Levin LR, Winger RC, Wang J, Arase H, Muller WA. Endothelial CD99 signals through soluble adenylyl cyclase and PKA to regulate leukocyte transendothelial migration. ACTA ACUST UNITED AC 2015; 212:1021-41. [PMID: 26101266 PMCID: PMC4493416 DOI: 10.1084/jem.20150354] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 05/14/2015] [Indexed: 12/30/2022]
Abstract
CD99 is a critical regulator of leukocyte transendothelial migration (TEM). Watson et al. describe the CD99 signaling pathway responsible. This involves a complex of CD99 with the A-kinase anchoring protein ezrin and soluble adenylyl cyclase that activates protein kinase A during leukocyte TEM. CD99 is a critical regulator of leukocyte transendothelial migration (TEM). How CD99 signals during this process remains unknown. We show that during TEM, endothelial cell (EC) CD99 activates protein kinase A (PKA) via a signaling complex formed with the lysine-rich juxtamembrane cytoplasmic tail of CD99, the A-kinase anchoring protein ezrin, and soluble adenylyl cyclase (sAC). PKA then stimulates membrane trafficking from the lateral border recycling compartment to sites of TEM, facilitating the passage of leukocytes across the endothelium. Pharmacologic or genetic inhibition of EC sAC or PKA, like CD99 blockade, arrests neutrophils and monocytes partway through EC junctions, in vitro and in vivo, without affecting leukocyte adhesion or the expression of relevant cellular adhesion molecules. This is the first description of the CD99 signaling pathway in TEM as well as the first demonstration of a role for sAC in leukocyte TEM.
Collapse
Affiliation(s)
- Richard L Watson
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60208
| | - Jochen Buck
- Department of Pharmacology, Weill Medical College of Cornell University, New York, NY 10065
| | - Lonny R Levin
- Department of Pharmacology, Weill Medical College of Cornell University, New York, NY 10065
| | - Ryan C Winger
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60208
| | - Jing Wang
- Laboratory of Immunochemistry, WPI Immunology Frontier Research Center and Department of Immunochemistry, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Hisashi Arase
- Laboratory of Immunochemistry, WPI Immunology Frontier Research Center and Department of Immunochemistry, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - William A Muller
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60208
| |
Collapse
|
24
|
Wang R, Ferraris JD, Izumi Y, Dmitrieva N, Ramkissoon K, Wang G, Gucek M, Burg MB. Global discovery of high-NaCl-induced changes of protein phosphorylation. Am J Physiol Cell Physiol 2014; 307:C442-54. [PMID: 24965592 DOI: 10.1152/ajpcell.00379.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High extracellular NaCl, such as in the renal medulla, can perturb and even kill cells, but cells mount protective responses that enable them to survive and function. Many high-NaCl-induced perturbations and protective responses are known, but the signaling pathways involved are less clear. Change in protein phosphorylation is a common mode of cell signaling, but there was no unbiased survey of protein phosphorylation in response to high NaCl. We used stable isotopic labeling of amino acids in cell culture coupled to mass spectrometry to identify changes in protein phosphorylation in human embryonic kidney (HEK 293) cells exposed to high NaCl. We reproducibly identify >8,000 unique phosphopeptides in 4 biological replicate samples with a 1% false discovery rate. High NaCl significantly changed phosphorylation of 253 proteins. Western analysis and targeted ion selection mass spectrometry confirm a representative sample of the phosphorylation events. We analyze the affected proteins by functional category to infer how altered protein phosphorylation might signal cellular responses to high NaCl, including alteration of cell cycle, cyto/nucleoskeletal organization, DNA double-strand breaks, transcription, proteostasis, metabolism of mRNA, and cell death.
Collapse
Affiliation(s)
- Rong Wang
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Joan D Ferraris
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Yuichiro Izumi
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Natalia Dmitrieva
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Kevin Ramkissoon
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Guanghui Wang
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Marjan Gucek
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Maurice B Burg
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| |
Collapse
|
25
|
Wang S, Linde MH, Munde M, Carvalho VD, Wilson WD, Poon GMK. Mechanistic heterogeneity in site recognition by the structurally homologous DNA-binding domains of the ETS family transcription factors Ets-1 and PU.1. J Biol Chem 2014; 289:21605-16. [PMID: 24952944 DOI: 10.1074/jbc.m114.575340] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
ETS family transcription factors regulate diverse genes through binding at cognate DNA sites that overlap substantially in sequence. The DNA-binding domains of ETS proteins (ETS domains) are highly conserved structurally yet share limited amino acid homology. To define the mechanistic implications of sequence diversity within the ETS family, we characterized the thermodynamics and kinetics of DNA site recognition by the ETS domains of Ets-1 and PU.1, which represent the extremes in amino acid divergence among ETS proteins. Even though the two ETS domains bind their optimal sites with similar affinities under physiologic conditions, their nature of site recognition differs strikingly in terms of the role of hydration and counter ion release. The data suggest two distinct mechanisms wherein Ets-1 follows a "dry" mechanism that rapidly parses sites through electrostatic interactions and direct protein-DNA contacts, whereas PU.1 utilizes hydration to interrogate sequence-specific sites and form a long-lived complex relative to the Ets-1 counterpart. The kinetic persistence of the high affinity PU.1 · DNA complex may be relevant to an emerging role of PU.1, but not Ets-1, as a pioneer transcription factor in vivo. In addition, PU.1 activity is critical to the development and function of macrophages and lymphocytes, which present osmotically variable environments, and hydration-dependent specificity may represent an important regulatory mechanism in vivo, a hypothesis that finds support in gene expression profiles of primary murine macrophages.
Collapse
Affiliation(s)
- Shuo Wang
- From the Department of Chemistry, Georgia State University, Atlanta, Georgia 30303 and
| | - Miles H Linde
- the Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington 99210-1495
| | - Manoj Munde
- From the Department of Chemistry, Georgia State University, Atlanta, Georgia 30303 and
| | - Victor D Carvalho
- the Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington 99210-1495
| | - W David Wilson
- From the Department of Chemistry, Georgia State University, Atlanta, Georgia 30303 and
| | - Gregory M K Poon
- the Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington 99210-1495
| |
Collapse
|
26
|
Jantsch J, Binger KJ, Müller DN, Titze J. Macrophages in homeostatic immune function. Front Physiol 2014; 5:146. [PMID: 24847274 PMCID: PMC4017126 DOI: 10.3389/fphys.2014.00146] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/27/2014] [Indexed: 01/20/2023] Open
Abstract
Macrophages are not only involved in inflammatory and anti-infective processes, but also play an important role in maintaining tissue homeostasis. In this review, we summarize recent evidence investigating the role of macrophages in controlling angiogenesis, metabolism as well as salt and water balance. Particularly, we summarize the importance of macrophage tonicity enhancer binding protein (TonEBP, also termed nuclear factor of activated T-cells 5 [NFAT5]) expression in the regulation of salt and water homeostasis. Further understanding of homeostatic macrophage function may lead to new therapeutic approaches to treat ischemia, hypertension and metabolic disorders.
Collapse
Affiliation(s)
- Jonathan Jantsch
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen und Friedrich-Alexander-Universität Erlangen-Nürnberg Erlangen, Germany
| | - Katrina J Binger
- Experimental and Clinical Research Center (ECRC), Max-Delbrück Center for Molecular Medicine, Charité Medical Faculty Berlin, Germany
| | - Dominik N Müller
- Experimental and Clinical Research Center (ECRC), Max-Delbrück Center for Molecular Medicine, Charité Medical Faculty Berlin, Germany
| | - Jens Titze
- Interdisciplinary Center for Clinical Research and Department of Nephrology and Hypertension, Friedrich-Alexander-Universität Erlangen-Nürnberg Erlangen, Germany ; Divison of Clinical Pharmacology, Vanderbilt University School of Medicine Nashville, TN, USA
| |
Collapse
|
27
|
Izumi Y, Burg MB, Ferraris JD. 14-3-3-β and -{varepsilon} contribute to activation of the osmoprotective transcription factor NFAT5 by increasing its protein abundance and its transactivating activity. Physiol Rep 2014; 2:e12000. [PMID: 24771694 PMCID: PMC4001879 DOI: 10.14814/phy2.12000] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Having previously found that high NaCl causes rapid exit of 14‐3‐3 isoforms from the nucleus, we used siRNA‐mediated knockdown to test whether 14‐3‐3s contribute to the high NaCl‐induced increase in the activity of the osmoprotective transcription factor NFAT5. We find that, when NaCl is elevated, knockdown of 14‐3‐3‐β and/or 14‐3‐3‐ε decreases NFAT5 transcriptional activity, as assayed both by luciferase reporter and by the mRNA abundance of the NFAT5 target genes aldose reductase and the sodium‐ and chloride‐dependent betaine transporter, BGT1. Knockdown of other 14‐3‐3 isoforms does not significantly affect NFAT5 activity. 14‐3‐3‐β and/or 14‐3‐3‐ε do not act by affecting the nuclear localization of NFAT5, but by at least two other mechanisms: (1) 14‐3‐3‐β and 14‐3‐3‐ε increase protein abundance of NFAT5 and (2) they increase NFAT5 transactivating activity. When NaCl is elevated, knockdown of 14‐3‐3‐β and/or 14‐3‐3‐ε reduces the protein abundance of NFAT5, as measured by Western blot, without affecting the level of NFAT5 mRNA, and the knockdown also decreases NFAT5 transactivating activity, as measured by luciferase reporter. The 14‐3‐3s increase NFAT5 protein, not by increasing its translation, but by decreasing the rate at which it is degraded, as measured by cycloheximide chase. It is not clear at this point whether the 14‐3‐3s affect NFAT5 directly or indirectly through their effects on other proteins that signal activation of NFAT5. e12000 When NaCl is elevated, knockdown of 14‐3‐3‐β and/or 14‐3‐3‐ε reduces the protein abundance of NFAT5, as measured by Western blot, without affecting the level of NFAT5 mRNA, and the knockdown also decreases NFAT5 transactivating activity, as measured by luciferase reporter. The 14‐3‐3s increase NFAT5 protein, not by increasing its translation, but by decreasing the rate at which it is degraded, as measured by cycloheximide chase.
Collapse
Affiliation(s)
- Yuichiro Izumi
- Systems Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | | | | |
Collapse
|
28
|
Yip YY, Yeap YYC, Bogoyevitch MA, Ng DCH. cAMP-dependent protein kinase and c-Jun N-terminal kinase mediate stathmin phosphorylation for the maintenance of interphase microtubules during osmotic stress. J Biol Chem 2013; 289:2157-69. [PMID: 24302736 DOI: 10.1074/jbc.m113.470682] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Dynamic microtubule changes after a cell stress challenge are required for cell survival and adaptation. Stathmin (STMN), a cytoplasmic microtubule-destabilizing phosphoprotein, regulates interphase microtubules during cell stress, but the signaling mechanisms involved are poorly defined. In this study ectopic expression of single alanine-substituted phospho-resistant mutants demonstrated that STMN Ser-38 and Ser-63 phosphorylation were specifically required to maintain interphase microtubules during hyperosmotic stress. STMN was phosphorylated on Ser-38 and Ser-63 in response to hyperosmolarity, heat shock, and arsenite treatment but rapidly dephosphorylated after oxidative stress treatment. Two-dimensional PAGE and Phos-tag gel analysis of stress-stimulated STMN phospho-isoforms revealed rapid STMN Ser-38 phosphorylation followed by subsequent Ser-25 and Ser-63 phosphorylation. Previously, we delineated stress-stimulated JNK targeting of STMN. Here, we identified cAMP-dependent protein kinase (PKA) signaling as responsible for stress-induced STMN Ser-63 phosphorylation. Increased cAMP levels induced by cholera toxin triggered potent STMN Ser-63 phosphorylation. Osmotic stress stimulated an increase in PKA activity and elevated STMN Ser-63 and CREB (cAMP-response element-binding protein) Ser-133 phosphorylation that was substantially attenuated by pretreatment with H-89, a PKA inhibitor. Interestingly, PKA activity and subsequent phosphorylation of STMN were augmented in the absence of JNK activation, indicating JNK and PKA pathway cross-talk during stress regulation of STMN. Taken together our study indicates that JNK- and PKA-mediated STMN Ser-38 and Ser-63 phosphorylation are required to preserve interphase microtubules in response to hyperosmotic stress.
Collapse
Affiliation(s)
- Yan Y Yip
- From the Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | | | | | | |
Collapse
|
29
|
Cheung CY, Ko BC. NFAT5 in cellular adaptation to hypertonic stress - regulations and functional significance. J Mol Signal 2013; 8:5. [PMID: 23618372 PMCID: PMC3655004 DOI: 10.1186/1750-2187-8-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 04/11/2013] [Indexed: 12/22/2022] Open
Abstract
The Nuclear Factor of Activated T Cells-5 (NFAT5), also known as OREBP or TonEBP, is a member of the nuclear factors of the activated T cells family of transcription factors. It is also the only known tonicity-regulated transcription factor in mammals. NFAT5 was initially known for its role in the hypertonic kidney inner medulla for orchestrating a genetic program to restore the cellular homeostasis. Emerging evidence, however, suggests that NFAT5 might play a more diverse functional role, including a pivotal role in blood pressure regulation and the development of autoimmune diseases. Despite the growing significance of NFAT5 in physiology and diseases, our understanding of how its activity is regulated remains very limited. Furthermore, how changes in tonicities are converted into functional outputs via NFAT5 remains elusive. Therefore, this review aims to summarize our current knowledge on the functional roles of NFAT5 in osmotic stress adaptation and the signaling pathways that regulate its activity.
Collapse
Affiliation(s)
- Chris Yk Cheung
- Department of Anatomical and Cellular Pathology, and The State Key Laboratory in Oncology in South China, The Chinese University of Hong Kong, The Prince of Wales Hospital, Rm 38019, Clinical Sciences Building, Shatin, Hong Kong, China.
| | | |
Collapse
|
30
|
Zhou X, Wang H, Burg MB, Ferraris JD. Inhibitory phosphorylation of GSK-3β by AKT, PKA, and PI3K contributes to high NaCl-induced activation of the transcription factor NFAT5 (TonEBP/OREBP). Am J Physiol Renal Physiol 2013; 304:F908-17. [PMID: 23324178 DOI: 10.1152/ajprenal.00591.2012] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
High NaCl activates the transcription factor nuclear factor of activated T cells 5 (NFAT5), leading to increased transcription of osmoprotective target genes. Kinases PKA, PI3K, AKT1, and p38α were known to contribute to the high NaCl-induced increase of NFAT5 activity. We now identify another kinase, GSK-3β. siRNA-mediated knock-down of GSK-3β increases NFAT5 transcriptional and transactivating activities without affecting high NaCl-induced nuclear localization of NFAT5 or NFAT5 protein expression. High NaCl increases phosphorylation of GSK-3β-S9, which inhibits GSK-3β. In GSK-3β-null mouse embryonic fibroblasts transfection of GSK-3β, in which serine 9 is mutated to alanine, so that it cannot be inhibited by phosphorylation at that site, inhibits high NaCl-induced NFAT5 transcriptional activity more than transfection of wild-type GSK-3β. High NaCl-induced phosphorylation of GSK-3β-S9 depends on PKA, PI3K, and AKT, but not p38α. Overexpression of PKA catalytic subunit α or of catalytically active AKT1 reduces inhibition of NFAT5 by GSK-3β, but overexpression of p38α together with its catalytically active upstream kinase, MKK6, does not. Thus, GSK-3β normally inhibits NFAT5 by suppressing its transactivating activity. When activated by high NaCl, PKA, PI3K, and AKT1, but not p38α, increase phosphorylation of GSK-3β-S9, which reduces the inhibitory effect of GSK-3β on NFAT5, and thus contributes to activation of NFAT5.
Collapse
Affiliation(s)
- Xiaoming Zhou
- Department of Medicine, Uniformed Services University, 4301 Jones Bridge Rd., Bethesda, MD 20814, USA.
| | | | | | | |
Collapse
|
31
|
Effect of Atractylodes macrocephala on Hypertonic Stress-Induced Water Channel Protein Expression in Renal Collecting Duct Cells. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:650809. [PMID: 23258995 PMCID: PMC3522508 DOI: 10.1155/2012/650809] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 10/15/2012] [Accepted: 10/15/2012] [Indexed: 11/17/2022]
Abstract
Edema is a symptom that results from the abnormal accumulation of fluid in the body. The cause of edema is related to the level of aquaporin (AQP)2 protein expression, which regulates the reabsorption of water in the kidney. Edema is caused by overexpression of the AQP2 protein when the concentration of Na+ in the blood increases. The rhizome of Atractylodes macrocephala has been used in traditional oriental medicine as a diuretic drug; however, the mechanism responsible for the diuretic effect of the aqueous extract from A. macrocephala rhizomes (AAMs) has not yet been identified. We examined the effect of the AAM on the regulation of water channels in the mouse inner medullary collecting duct (mIMCD)-3 cells under hypertonic stress. Pretreatment of AAM attenuates a hypertonicity-induced increase in AQP2 expression as well as the trafficking of AQP2 to the apical plasma membrane. Tonicity-responsive enhancer binding protein (TonEBP) is a transcription factor known to play a central role in cellular homeostasis by regulating the expression of some proteins, including AQP2. Western immunoblot analysis demonstrated that the protein and mRNA expression levels of TonEBP also decrease after AAM treatment. These results suggest that the AAM has a diuretic effect by suppressing water reabsorption via the downregulation of the TonEBP-AQP2 signaling pathway.
Collapse
|
32
|
Abstract
Transcriptional coactivator with PDZ-binding motif (TAZ) physically interacts with a variety of transcription factors and modulates their activities involved in cell proliferation and mesenchymal stem cell differentiation. TAZ is highly expressed in the kidney, and a deficiency of this protein results in multiple renal cysts and urinary concentration defects; however, the molecular functions of TAZ in renal cells remain largely unknown. In this study, we examined the effects of osmotic stress on TAZ expression and activity in renal cells. We found that hyperosmotic stress selectively increased protein phosphorylation at tyrosine 316 of TAZ and that this was enhanced by c-Abl activation in response to hyperosmotic stress. Interestingly, phosphorylated TAZ physically interacted with nuclear factor of activated T cells 5 (NFAT5), a major osmoregulatory transcription factor, and subsequently suppressed DNA binding and transcriptional activity of NFAT5. Furthermore, TAZ deficiency elicited an increase in NFAT5 activity in vitro and in vivo, which then reverted to basal levels following restoration of wild-type TAZ but not mutant TAZ (Y316F). Collectively, the data suggest that TAZ modulates cellular responses to hyperosmotic stress through fine-tuning of NFAT5 activity via tyrosine phosphorylation.
Collapse
|
33
|
Hernández-Ochoa EO, Robison P, Contreras M, Shen T, Zhao Z, Schneider MF. Elevated extracellular glucose and uncontrolled type 1 diabetes enhance NFAT5 signaling and disrupt the transverse tubular network in mouse skeletal muscle. Exp Biol Med (Maywood) 2012; 237:1068-83. [PMID: 22966145 DOI: 10.1258/ebm.2012.012052] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The transcription factor nuclear factor of activated T-cells 5 (NFAT5) is a key protector from hypertonic stress in the kidney, but its role in skeletal muscle is unexamined. Here, we evaluate the effects of glucose hypertonicity and hyperglycemia on endogenous NFAT5 activity, transverse tubular system morphology and Ca(2+) signaling in adult murine skeletal muscle fibers. We found that exposure to elevated glucose (25-50 mmol/L) increased NFAT5 expression and nuclear translocation, and NFAT-driven transcriptional activity. These effects were insensitive to the inhibition of calcineurin A, but sensitive to both p38α mitogen-activated protein kinases and phosphoinositide 3-kinase-related kinase inhibition. Fibers exposed to elevated glucose exhibited disrupted transverse tubular morphology, characterized by swollen transverse tubules and an increase in longitudinal connections between adjacent transverse tubules. Ca(2+) transients elicited by a single, brief electric field stimuli were increased in amplitude in fibers challenged by elevated glucose. Muscle fibers from type 1 diabetic mice exhibited increased NFAT5 expression and transverse tubule disruptions, but no differences in electrically evoked Ca(2+) transients. Our results suggest the hypothesis that these changes in skeletal muscle could play a role in the pathophysiology of acute and severe hyperglycemic episodes commonly observed in uncontrolled diabetes.
Collapse
Affiliation(s)
- Erick O Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland, School of Medicine, Baltimore, MD 21201, USA.
| | | | | | | | | | | |
Collapse
|
34
|
NFAT5 is activated by hypoxia: role in ischemia and reperfusion in the rat kidney. PLoS One 2012; 7:e39665. [PMID: 22768306 PMCID: PMC3388090 DOI: 10.1371/journal.pone.0039665] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 05/27/2012] [Indexed: 12/13/2022] Open
Abstract
The current hypothesis postulates that NFAT5 activation in the kidney's inner medulla is due to hypertonicity, resulting in cell protection. Additionally, the renal medulla is hypoxic (10–18 mmHg); however there is no information about the effect of hypoxia on NFAT5. Using in vivo and in vitro models, we evaluated the effect of reducing the partial pressure of oxygen (PO2) on NFAT5 activity. We found that 1) Anoxia increased NFAT5 expression and nuclear translocation in primary cultures of IMCD cells from rat kidney. 2) Anoxia increased transcriptional activity and nuclear translocation of NFAT5 in HEK293 cells. 3) The dose-response curve demonstrated that HIF-1α peaked at 2.5% and NFAT5 at 1% of O2. 4) At 2.5% of O2, the time-course curve of hypoxia demonstrated earlier induction of HIF-1α gene expression than NFAT5. 5) siRNA knockdown of NFAT5 increased the hypoxia-induced cell death. 6) siRNA knockdown of HIF-1α did not affect the NFAT5 induction by hypoxia. Additionally, HIF-1α was still induced by hypoxia even when NFAT5 was knocked down. 7) NFAT5 and HIF-1α expression were increased in kidney (cortex and medulla) from rats subjected to an experimental model of ischemia and reperfusion (I/R). 7) Experimental I/R increased the NFAT5-target gene aldose reductase (AR). 8) NFAT5 activators (ATM and PI3K) were induced in vitro (HEK293 cells) and in vivo (I/R kidneys) with the same timing of NFAT5. 8) Wortmannin, which inhibits ATM and PI3K, reduces hypoxia-induced NFAT5 transcriptional activation in HEK293 cells. These results demonstrate for the first time that NFAT5 is induced by hypoxia and could be a protective factor against ischemic damage.
Collapse
|
35
|
Vio CP, Quiroz-Munoz M, Cuevas CA, Cespedes C, Ferreri NR. Prostaglandin E2 EP3 receptor regulates cyclooxygenase-2 expression in the kidney. Am J Physiol Renal Physiol 2012; 303:F449-57. [PMID: 22622465 DOI: 10.1152/ajprenal.00634.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Cyclooxygenase-2 (COX-2) is constitutively expressed and highly regulated in the thick ascending limb (TAL). As COX-2 inhibitors (Coxibs) increase COX-2 expression, we tested the hypothesis that a negative feedback mechanism involving PGE(2) EP3 receptors regulates COX-2 expression in the TAL. Sprague-Dawley rats were treated with a Coxib [celecoxib (20 mg·kg(-1)·day(-1)) or rofecoxib (10 mg·kg(-1)·day(-1))], with or without sulprostone (20 μg·kg(-1)·day(-1)). Sulprostone was given using two protocols, namely, previous to Coxib treatment (prevention effect; Sulp7-Coxib5 group) and 5 days after initiation of Coxib treatment (regression effect; Coxib10-Sulp5 group). Immunohistochemical and morphometric analysis revealed that the stained area for COX-2-positive TAL cells (μm(2)/field) increased in Coxib-treated rats (Sham: 412 ± 56.3, Coxib: 794 ± 153.3). The Coxib effect was inhibited when sulprostone was used in either the prevention (285 ± 56.9) or regression (345 ± 51.1) protocols. Western blot analysis revealed a 2.1 ± 0.3-fold increase in COX-2 protein expression in the Coxib-treated group, an effect abolished by sulprostone using either the prevention (1.2 ± 0.3-fold) or regression (0.6 ± 0.4-fold vs. control, P < 0.05) protocols. Similarly, the 6.4 ± 0.6-fold increase in COX-2 mRNA abundance induced by Coxibs (P < 0.05) was inhibited by sulprostone; prevention: 0.9 ± 0.3-fold (P < 0.05) and regression: 0.6 ± 0.1 (P < 0.05). Administration of a selective EP3 receptor antagonist, L-798106, also increased the area for COX-2-stained cells, COX-2 mRNA accumulation, and protein expression in the TAL. Collectively, the data suggest that COX-2 levels are regulated by a novel negative feedback loop mediated by PGE(2) acting on its EP3 receptor in the TAL.
Collapse
Affiliation(s)
- Carlos P Vio
- Dept. of Physiology, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Alameda 340, Santiago, Chile.
| | | | | | | | | |
Collapse
|
36
|
Gogate SS, Fujita N, Skubutyte R, Shapiro IM, Risbud MV. Tonicity enhancer binding protein (TonEBP) and hypoxia-inducible factor (HIF) coordinate heat shock protein 70 (Hsp70) expression in hypoxic nucleus pulposus cells: role of Hsp70 in HIF-1α degradation. J Bone Miner Res 2012; 27:1106-17. [PMID: 22322648 PMCID: PMC3330204 DOI: 10.1002/jbmr.1571] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The objective of our study was to examine the regulation of hypoxic expression of heat shock protein 70 (Hsp70) in nucleus pulposus cells and to determine if Hsp70 promoted hypoxia-inducible factor (HIF)-1α degradation. Rat nucleus pulposus cells were maintained in culture in either 21% or 1% oxygen. To determine the regulation of Hsp70 expression by tonicity enhancer binding protein (TonEBP) and HIF-1/2, loss-of-function and gain-of-function experiments and mutational analysis of the Hsp70 promoter were performed. Hypoxia increased Hsp70 expression in nucleus pulposus cells. Noteworthy, hypoxia increased TonEBP transactivation and mutation of TonE motifs blocked hypoxic induction of the Hsp70 promoter. In contrast, mutation of hypoxia response element (HRE) motifs coupled with loss-of-function experiments suggested that HIF-1 and HIF-2 suppressed Hsp70 promoter activity and transcription. Interestingly, HIF-α interferes with TonEBP function and suppresses the inductive effect of TonEBP on the Hsp70 promoter. In terms of Hsp70 function, when treated with Hsp70 transcriptional inhibitor, KNK437, there was an increase in HIF-1α protein stability and transcriptional activity. Likewise, when Hsp70 was overexpressed, the stability of HIF-1α and its transcriptional activity decreased. Hsp70 interacted with HIF-1α under hypoxic conditions and evidenced increased binding when treated with MG132, a proteasomal inhibitor. These results suggest that Hsp70 may promote HIF-1α degradation through the proteasomal pathway in nucleus pulposus cells. In hypoxic and hyperosmolar nucleus pulposus cells, Hsp70, TonEBP, and HIFs form a regulatory loop. We propose that the positive regulation by TonEBP and negative regulation of Hsp70 by HIF-1 and HIF-2 may serve to maintain Hsp70 levels in these cells, whereas Hsp70 may function in controlling HIF-1α homeostasis.
Collapse
Affiliation(s)
- Shilpa S Gogate
- Department of Orthopaedic Surgery and Graduate Program in Cell and Developmental Biology, Jefferson Medical College, Philadelphia, PA 19107, USA
| | | | | | | | | |
Collapse
|
37
|
Ito A, Shirakawa H, Takumi N, Minegishi Y, Ohashi A, Howlader ZH, Ohsaki Y, Sato T, Goto T, Komai M. Menaquinone-4 enhances testosterone production in rats and testis-derived tumor cells. Lipids Health Dis 2011; 10:158. [PMID: 21914161 PMCID: PMC3180407 DOI: 10.1186/1476-511x-10-158] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 09/13/2011] [Indexed: 12/04/2022] Open
Abstract
Background Vitamin K is essential for the posttranslational modification of various Gla proteins. Although it is widespread in several organs, including the testis, the function of vitamin K in these organs is not well characterized. In this study, we investigated the function of vitamin K in the testis and analyzed its role in steroidogenesis. Methods Eight-week-old male Wistar rats were fed a diet supplemented with menaquinone-4 (MK-4, 75 mg/kg diet), one of the predominant K2 vitamins present in the testis, for 5 weeks. In vivo testosterone levels of the rats' plasma and testes were measured by enzyme-linked immunosorbent assay, and in vitro testosterone levels of testis-derived tumor cells (I-10 cells) maintained in Ham's F-10 medium with 10% fetal bovine serum were measured following treatment with MK-4 (0 to 100 μM) at several time points. Testosterone and cellular protein levels were analyzed with respect to their effects on steroidogenesis. Results Testosterone levels in the plasma and testes of MK-4-fed rats were significantly increased compared to those of control rats, with no obvious differences in plasma luteinizing hormone levels. Secreted testosterone levels from I-10 cells were elevated by MK-4, but not by vitamin K1, in a dose-dependent manner independent of cAMP treatment. Western blot analysis revealed that expression of CYP11A, the rate-limiting enzyme in steroidogenesis, and phosphorylation levels of protein kinase A (PKA) and the cAMP response element-binding protein were all stimulated by the presence of MK-4. Enhancement of testosterone production was inhibited by H89, a specific inhibitor of PKA, but not by warfarin, an inhibitor of γ-glutamylcarboxylation. Conclusions MK-4 stimulates testosterone production in rats and testis-derived tumor cells via activation of PKA. MK-4 may be involved in steroidogenesis in the testis, and its supplementation could reverse the downregulation of testosterone production in elders.
Collapse
Affiliation(s)
- Asagi Ito
- Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
IMPORTANCE OF THE FIELD Recently-discovered tonicity-dependence of human CYP3A expression in vitro may be a novel mechanism of CYP3A regulation in the intestinal epithelia, which exists in a dynamic osmotic environment influenced by food intake. AREAS COVERED IN THIS REVIEW A combination of focused and comprehensive literature searches to identify any relevant reports using Medline (from 1950 to 7 November 2009) through the OVID system. WHAT THE READER WILL GAIN An update on current knowledge on osmotic environment in the gastrointestinal (GI) tract and its impact on intestinal CYP3A expression and function with special emphasis on the tonicity-sensitive transcription factor nuclear factor of activated T cells 5 (NFAT5). TAKE HOME MESSAGE In vitro hypertonicity of ambient osmotic environment in cultured human cells increases expression of CYP3A through transcriptional enhancement by osmosensitive NFAT5. Although post-prandial osmolality in the GI lumen in vivo is substantially increased, NFAT5 activation has not been reported. Similarly, high-salt diet increases intestinal CYP3A function in humans, but it is not known whether these changes are mediated directly by NFAT5.
Collapse
Affiliation(s)
- Andrew I Chuang
- Department of Pharmacology, University of Toronto, Ontario, Canada
| | | |
Collapse
|
39
|
Kunin M, Dmitrieva NI, Gallazzini M, Shen RF, Wang G, Burg MB, Ferraris JD. Mediator of DNA damage checkpoint 1 (MDC1) contributes to high NaCl-induced activation of the osmoprotective transcription factor TonEBP/OREBP. PLoS One 2010; 5:e12108. [PMID: 20711462 PMCID: PMC2920327 DOI: 10.1371/journal.pone.0012108] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 07/12/2010] [Indexed: 01/17/2023] Open
Abstract
Background Hypertonicity, such as induced by high NaCl, increases the activity of the transcription factor TonEBP/OREBP whose target genes increase osmoprotective organic osmolytes and heat shock proteins. Methodology We used mass spectrometry to analyze proteins that coimmunoprecipitate with TonEBP/OREBP in order to identify ones that might contribute to its high NaCl-induced activation. Principal Findings We identified 20 unique peptides from Mediator of DNA Damage Checkpoint 1 (MDC1) with high probability. The identification was confirmed by Western analysis. We used small interfering RNA knockdown of MDC1 to characterize its osmotic function. Knocking down MDC1 reduces high NaCl-induced increases in TonEBP/OREBP transcriptional and transactivating activity, but has no significant effect on its nuclear localization. We confirm six previously known phosphorylation sites in MDC1, but do not find evidence that high NaCl increases phosphorylation of MDC1. It is suggestive that MDC1 acts as a DNA damage response protein since hypertonicity reversibly increases DNA breaks, and other DNA damage response proteins, like ATM, also associate with TonEBP/OREBP and contribute to its activation by hypertonicity. Conclusions/Significance MDC1 associates with TonEBP/OREBP and contributes to high NaCl-induced increase of that factor's transcriptional activity.
Collapse
Affiliation(s)
- Margarita Kunin
- Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung and Blood Institute, Bethesda, Maryland, United States of America
| | - Natalia I. Dmitrieva
- Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung and Blood Institute, Bethesda, Maryland, United States of America
| | - Morgan Gallazzini
- Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung and Blood Institute, Bethesda, Maryland, United States of America
| | - Rong-Fong Shen
- Proteomics Core Facility, National Heart, Lung and Blood Institute, Bethesda, Maryland, United States of America
| | - Guanghui Wang
- Proteomics Core Facility, National Heart, Lung and Blood Institute, Bethesda, Maryland, United States of America
| | - Maurice B. Burg
- Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung and Blood Institute, Bethesda, Maryland, United States of America
- * E-mail:
| | - Joan D. Ferraris
- Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung and Blood Institute, Bethesda, Maryland, United States of America
| |
Collapse
|
40
|
Gallazzini M, Yu MJ, Gunaratne R, Burg MB, Ferraris JD. c-Abl mediates high NaCl-induced phosphorylation and activation of the transcription factor TonEBP/OREBP. FASEB J 2010; 24:4325-35. [PMID: 20585028 DOI: 10.1096/fj.10-157362] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The transcription factor TonEBP/OREBP promotes cell survival during osmotic stress. High NaCl-induced phosphorylation of TonEBP/OREBP at tyrosine-143 was known to be an important factor in increasing its activity in cell culture. We now find that TonEBP/OREBP also is phosphorylated at tyrosine-143 in rat renal inner medulla, dependent on the interstitial osmolality. c-Abl seemed likely to be the kinase that phosphorylates TonEBP/OREBP because Y143 is in a consensus c-Abl phosphorylation site. We now confirm that, as follows. High NaCl increases c-Abl activity. Specific inhibition of c-Abl by imatinib, siRNA, or c-Abl kinase dead drastically reduces high NaCl-induced TonEBP/OREBP activity by reducing its nuclear location and transactivating activity. c-Abl associates with TonEBP/OREBP (coimmunoprecipitation) and phosphorylates TonEBP/OREBP-Y143 both in cell and in vitro. High NaCl-induced activation of ataxia telangiectasia mutated, previously known to contribute to activation of TonEBP/OREBP, depends on c-Abl activity. Thus, c-Abl is the kinase responsible for high NaCl-induced phosphorylation of TonEBP/OREBP-Y143, which contributes to its increased activity.
Collapse
Affiliation(s)
- Morgan Gallazzini
- Laboratory of Kidney and Electrolyte Metabolism, National Heart Lung and Blood Institute, Bethesda, MD 20892-1603,
| | | | | | | | | |
Collapse
|
41
|
Chen YQ, Xie X. Podophyllotoxin induces CREB phosphorylation and CRE-driven gene expression via PKA but not MAPKs. Mol Cells 2010; 29:41-50. [PMID: 20033853 DOI: 10.1007/s10059-010-0015-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 10/15/2009] [Accepted: 10/20/2009] [Indexed: 12/11/2022] Open
Abstract
CRE-driven luciferase reporter is commonly used in drug screening systems involving G protein-coupled receptors (GPCRs). In a screen campaign designed to search for melanocortin-4 receptor (MC4R) agonists, podophyllotoxin, a microtubules disruptor, was found to induce cAMP-responsive element (CRE)-driven reporter expression. MC4R was not involved because podophyllotoxin induced CREB activation and CRE-driven transcription in cells not expressing MC4R. Previous studies indicated that intracellular calcium, PKA, and MAPKs are involved in CREB phosphorylation and activation. Our studies revealed that podophyllotoxin did not affect intracellular calcium level and the phosphorylation state of p38. Podophyllotoxin induced JNK and ERK activation, but blockade of JNK and ERK activation with specific inhibitors had no effect on podophyllotoxin-induced CREB activation and CRE-regulated gene expression. Further experiments revealed that H89, a specific inhibitor of PKA, significantly inhibited podophyllotoxin-induced CREB activation. Podophyllotoxin itself did not alter intracellular cAMP level. Taken together, podophyllotoxin induces CREB activation and CRE-driven gene expression via PKA activation by a cAMP-independent mechanism.
Collapse
Affiliation(s)
- Ya Qiong Chen
- State Key Laboratory of Drug Research, National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | | |
Collapse
|
42
|
Tong EHY, Guo JJ, Xu SX, Mak K, Chung SK, Chung SSM, Huang AL, Ko BCB. Inducible nucleosome depletion at OREBP-binding-sites by hypertonic stress. PLoS One 2009; 4:e8435. [PMID: 20041176 PMCID: PMC2793017 DOI: 10.1371/journal.pone.0008435] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 11/22/2009] [Indexed: 01/01/2023] Open
Abstract
Background Osmotic Response Element-Binding Protein (OREBP), also known as TonEBP or NFAT5, is a unique transcription factor. It is hitherto the only known mammalian transcription factor that regulates hypertonic stress-induced gene transcription. In addition, unlike other monomeric members of the NFAT family, OREBP exists as a homodimer and it is the only transcription factor known to bind naked DNA targets by complete encirclement in vitro. Nevertheless, how OREBP interacts with target DNA, also known as ORE/TonE, and how it elicits gene transcription in vivo, remains unknown. Methodology Using hypertonic induction of the aldose reductase (AR) gene activation as a model, we showed that OREs contained dynamic nucleosomes. Hypertonic stress induced a rapid and reversible loss of nucleosome(s) around the OREs. The loss of nucleosome(s) was found to be initiated by an OREBP-independent mechanism, but was significantly potentiated in the presence of OREBP. Furthermore, hypertonic induction of AR gene was associated with an OREBP-dependent hyperacetylation of histones that spanned the 5′ upstream sequences and at least some exons of the gene. Nevertheless, nucleosome loss was not regulated by the acetylation status of histone. Significance Our findings offer novel insights into the mechanism of OREBP-dependent transcriptional regulation and provide a basis for understanding how histone eviction and transcription factor recruitment are coupled.
Collapse
Affiliation(s)
- Edith H. Y. Tong
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong, China
- State Key Laboratory in Oncology in South China, The Chinese University of Hong Kong, Hong Kong, China
- Department of Physiology, The University of Hong Kong, Hong Kong, China
| | - Jin-Jun Guo
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Institute of Viral Hepatitis, Chongqing University of Medical Sciences, Chong Qing, China
| | - Song-Xiao Xu
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong, China
- State Key Laboratory in Oncology in South China, The Chinese University of Hong Kong, Hong Kong, China
| | - Keri Mak
- Department of Anatomy, The University of Hong Kong, Hong Kong, China
| | - Sookja K. Chung
- Department of Anatomy, The University of Hong Kong, Hong Kong, China
| | | | - Ali-Long Huang
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Institute of Viral Hepatitis, Chongqing University of Medical Sciences, Chong Qing, China
| | - Ben C. B. Ko
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong, China
- State Key Laboratory in Oncology in South China, The Chinese University of Hong Kong, Hong Kong, China
- * E-mail:
| |
Collapse
|
43
|
Gu L, Lau SK, Loera S, Somlo G, Kane SE. Protein kinase A activation confers resistance to trastuzumab in human breast cancer cell lines. Clin Cancer Res 2009; 15:7196-206. [PMID: 19920112 DOI: 10.1158/1078-0432.ccr-09-0585] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
PURPOSE Trastuzumab is a monoclonal antibody targeted to the Her2 receptor and approved for treatment of Her2-positive breast cancer. Among patients who initially respond to trastuzumab therapy, resistance typically arises within 1 year. BT/Her(R) cells are trastuzumab-resistant variants of Her2-positive BT474 breast cancer cells. The salient feature of BT/Her(R) cells is failure to downregulate phosphoinositide 3-kinase/Akt signaling on trastuzumab binding. The current work addresses the mechanism of sustained signaling in BT/Her(R) cells, focusing on the protein kinase A (PKA) pathway. EXPERIMENTAL DESIGN We performed microarray analysis on BT/Her(R) and BT474 cell lines to identify genes that were upregulated or downregulated in trastuzumab-resistant cells. Specific genes in the PKA pathway were quantified using reverse transcription-PCR and Western hybridization. Small interfering RNA transfection was used to determine the effects of gene knockdown on cellular response to trastuzumab. Electrophoretic mobility shift assays were used to measure cyclic AMP-responsive element binding activity under defined conditions. Immunohistochemistry was used to analyze protein expression in clinical samples. RESULTS BT/Her(R) cells had elevated PKA signaling activity and several genes in the PKA regulatory network had altered expression in these cells. Downregulation of one such gene, the PKA-RIIalpha regulatory subunit, conferred partial trastuzumab resistance in Her2-positive BT474 and SK-Br-3 cell lines. Forskolin activation of PKA also produced significant protection against trastuzumab-mediated Akt dephosphorylation. In patient samples, PKA signaling appeared to be enhanced in residual disease remaining after trastuzumab-containing neoadjuvant therapy. CONCLUSIONS Activation of PKA signaling may be one mechanism contributing to trastuzumab resistance in Her2-positive breast cancer. We propose a molecular model by which PKA confers its effects.
Collapse
Affiliation(s)
- Long Gu
- Division of Tumor Cell Biology, City of Hope Comprehensive Cancer Center, Duarte, California 91107, USA
| | | | | | | | | |
Collapse
|
44
|
Simmons SO, Fan CY, Ramabhadran R. Cellular stress response pathway system as a sentinel ensemble in toxicological screening. Toxicol Sci 2009; 111:202-25. [PMID: 19567883 DOI: 10.1093/toxsci/kfp140] [Citation(s) in RCA: 204] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
High costs, long test times, and societal concerns related to animal use have required the development of in vitro assays for the rapid and cost-effective toxicological evaluation and characterization of compounds in both the pharmaceutical and environmental arenas. Although the pharmaceutical industry has developed very effective, high-throughput in vitro assays for determining the therapeutic potential of compounds, the application of this approach to toxicological screening has been limited. A primary reason for this is that while drug candidate screens are directed to a specific target/mechanism, xenobiotics can cause toxicity through any of a myriad of undefined interactions with cellular components and processes. Given that it is not practical to design assays that can interrogate each potential toxicological target, an integrative approach is required if there is to be a rapid and low-cost toxicological evaluation of chemicals. Cellular stress response pathways offer a viable solution to the creation of a set of integrative assays as there is a limited and hence manageable set (a small ensemble of 10 or less) of major cellular stress response pathways through which cells mount a homoeostatic response to toxicants and which also participate in cell fate/death decisions. Further, over the past decades, these pathways have been well characterized at a molecular level thereby enabling the development of high-throughput cell-based assays using the components of the pathways. Utilization of the set of cellular stress response pathway-based assays as indicators of toxic interactions of chemicals with basic cellular machinery will potentially permit the clustering of chemicals based on biological response profiles of common mode of action (MOA) and also the inference of the specific MOA of a toxicant. This article reviews the biochemical characteristics of the stress response pathways, their common architecture that enables rapid activation during stress, their participation in cell fate decisions, the essential nature of these pathways to the organism, and the biochemical basis of their cross-talk that permits an assay ensemble screening approach. Subsequent sections describe how the stress pathway ensemble assay approach could be applied to screening potentially toxic compounds and discuss how this approach may be used to derive toxicant MOA from the biological activity profiles that the ensemble strategy provides. The article concludes with a review of the application of the stress assay concept to noninvasive in vivo assessments of chemical toxicants.
Collapse
Affiliation(s)
- Steven O Simmons
- Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
| | | | | |
Collapse
|
45
|
Lim YS, Lee JS, Huang TQ, Seo JS. Protein kinase Cmu plays an essential role in hypertonicity-induced heat shock protein 70 expression. Exp Mol Med 2009; 40:596-606. [PMID: 19116445 DOI: 10.3858/emm.2008.40.6.596] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Heat shock protein 70 (HSP70), which evidences important functions as a molecular chaperone and anti-apoptotic molecule, is substantially induced in cells exposed to a variety of stresses, including hypertonic stress, heavy metals, heat shock, and oxidative stress, and prevents cellular damage under these conditions. However, the molecular mechanism underlying the induction of HSP70 in response to hypertonicity has been characterized to a far lesser extent. In this study, we have investigated the cellular signaling pathway of HSP70 induction under hypertonic conditions. Initially, we applied a variety of kinase inhibitors to NIH3T3 cells that had been exposed to hypertonicity. The induction of HSP70 was suppressed specifically by treatment with protein kinase C (PKC) inhibitors (Gö6976 and GF109203X). As hypertonicity dramatically increased the phosphorylation of PKCmu, we then evaluated the role of PKCmu in hypertonicity-induced HSP70 expression and cell viability. The depletion of PKCmu with siRNA or the inhibition of PKCmu activity with inhibitors resulted in a reduction in HSP70 induction and cell viability. Tonicity-responsive enhancer binding protein (TonEBP), a transcription factor for hypertonicity-induced HSP70 expression, was translocated rapidly into the nucleus and was modified gradually in the nucleus under hypertonic conditions. When we administered treatment with PKC inhibitors, the mobility shift of TonEBP was affected in the nucleus. However, PKCmu evidenced no subcellular co-localization with TonEBP during hypertonic exposure. From our results, we have concluded that PKCmu performs a critical function in hypertonicity-induced HSP70 induction, and finally cellular protection, via the indirect regulation of TonEBP modification.
Collapse
Affiliation(s)
- Yun Sook Lim
- ILCHUN Genomic Medicine Institute and Seoul National University College of Medicine, Seoul 110-799, Korea
| | | | | | | |
Collapse
|
46
|
Hasler U. Controlled aquaporin-2 expression in the hypertonic environment. Am J Physiol Cell Physiol 2009; 296:C641-53. [PMID: 19211910 DOI: 10.1152/ajpcell.00655.2008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The corticomedullary osmolality gradient is the driving force for water reabsorption occurring in the kidney. In the collecting duct, this gradient allows luminal water to move across aquaporin (AQP) water channels, thereby increasing urine concentration. However, this same gradient exposes renal cells to great osmotic challenges. These cells must constantly adapt to fluctuations of environmental osmolality that challenge cell volume and incite functional change. This implies profound alterations of cell phenotype regarding water permeability. AQP2 is an essential component of the urine concentration mechanism whose controlled expression dictates apical water permeability of collecting duct principal cells. This review focuses on changes of AQP2 abundance and trafficking in hypertonicity-challenged cells. Intracellular mechanisms governing these events are discussed and the biological relevance of altered AQP2 expression by hypertonicity is outlined.
Collapse
Affiliation(s)
- Udo Hasler
- Service de Néphrologie, Fondation pour Recherches Médicales, 64 Ave. de la Roseraie, CH-1211, Geneva 4, Switzerland.
| |
Collapse
|
47
|
Steinert D, Küper C, Bartels H, Beck FX, Neuhofer W. PGE2 potentiates tonicity-induced COX-2 expression in renal medullary cells in a positive feedback loop involving EP2-cAMP-PKA signaling. Am J Physiol Cell Physiol 2008; 296:C75-87. [PMID: 19005164 DOI: 10.1152/ajpcell.00024.2008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cyooxygenase-2 (COX-2)-derived PGE2 is critical for the integrity and function of renal medullary cells during antidiuresis. The present study extended our previous finding that tonicity-induced COX-2 expression is further stimulated by the major COX-2 product PGE2 and investigated the underlying signaling pathways and the functional relevance of this phenomenon. Hyperosmolality stimulated COX-2 expression and activity in Madin-Darby canine kidney (MDCK) cells, a response that was further increased by PGE2-cAMP signaling, suggesting the existence of a positive feedback loop. This effect was diminished by AH-6809, an EP2 antagonist, and by the PKA inhibitor H-89, but not by AH-23848, an EP4 antagonist. The effect of PGE2 was mimicked by forskolin and dibutyryl-cAMP, suggesting that the stimulatory effect of PGE2 on COX-2 is mediated by a cAMP-PKA-dependent mechanism. Accordingly, cAMP-responsive element (CRE)-driven reporter activity paralleled the effects of PGE2, AH-6809, AH-23848, H-89, forskolin, and dibutyryl-cAMP on COX-2 expression. In addition, the stimulatory effect of PGE2 on tonicity-induced COX-2 expression was blunted in cells transfected with dominant-negative CRE binding (CREB) protein, as was the case in a COX-2 promoter reporter construct in which a putative CRE was deleted. Furthermore, PGE2 resulted in PKA-dependent phosphorylation of the pro-apoptotic protein Bad at Ser155, a mechanism that is known to inactivate Bad, which coincided with reduced caspase-3 activity during osmotic stress. Conversely, pharmacological interruption of the PGE2-EP2-cAMP-PKA pathway abolished Ser155 phosphorylation of Bad and blunted the protective effect of PGE2 on cell survival during osmotic stress. These observations indicate the existence of a positive feedback loop of PGE2 on COX-2 expression during osmotic stress, an effect that apparently is mediated by EP2-cAMP-PKA signaling, and that contributes to cell survival under hypertonic conditions.
Collapse
Affiliation(s)
- Daniela Steinert
- Department of Physiology, University of Munich, Pettenkoferstrasse 12, 80336 Munich, Germany
| | | | | | | | | |
Collapse
|
48
|
Izumi Y, Nakayama Y, Memetimin H, Inoue T, Kohda Y, Nonoguchi H, Tomita K. Regulation of V2R transcription by hypertonicity and V1aR-V2R signal interaction. Am J Physiol Renal Physiol 2008; 295:F1170-6. [DOI: 10.1152/ajprenal.00119.2008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Arginine vasopressin (AVP) and hypertonicity in the renal medulla play a major role in the urine concentration mechanism. Previously, we showed that rat vasopressin V2 receptor (rV2R) promoter activity was increased by vasopressin V2R stimulation and decreased by vasopressin V1a receptor (V1aR) stimulation in a LLC-PK1 cell line stably expressing rat V1aR (LLC-PK1/rV1aR). In the present study, we investigated the effects of hypertonicity on the rV2R promoter activity and on the suppression of rV2R promoter activity by V1aR stimulation in LLC-PK1/rV1aR cells. rV2R promoter activity was increased in NaCl- or mannitol-induced hypertonicity. The hypertonicity-responsive site in the rV2R promoter region was limited to 10 bp, including the Sp1 motif. The increase of V2R promoter activity by hypertonicity was significantly inhibited by a JNK inhibitor (SP600125) and PKA inhibitor (H89). In contrast, rV2R promoter activity was remarkably suppressed by V1aR stimulation in the hypertonic condition rather than in the isotonic condition. The AVP-stimulated intracellular Ca2+ concentration was increased in the hypertonic condition, suggesting the functional activation of V1aR by hypertonicity. In conclusion, 1) V2R promoter activity is increased by hypertonicity via the JNK and PKA pathways, 2) suppression of V2R expression by the V1aR-Ca2+ pathway is enhanced by hypertonicity, and 3) hypertonicity enhances the V1aR-Ca2+ pathway. The counteractivity of V2R and V1aR could be required to maintain minimum urine volume in the dehydrated state.
Collapse
|
49
|
Hoffert JD, Fenton RA, Moeller HB, Simons B, Tchapyjnikov D, McDill BW, Yu MJ, Pisitkun T, Chen F, Knepper MA. Vasopressin-stimulated increase in phosphorylation at Ser269 potentiates plasma membrane retention of aquaporin-2. J Biol Chem 2008; 283:24617-27. [PMID: 18606813 PMCID: PMC2528999 DOI: 10.1074/jbc.m803074200] [Citation(s) in RCA: 211] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 06/17/2008] [Indexed: 11/06/2022] Open
Abstract
Vasopressin controls water excretion through regulation of aquaporin-2 (AQP2) trafficking in renal collecting duct cells. Using mass spectrometry, we previously demonstrated four phosphorylated serines (Ser256, Ser261, Ser264, and Ser269) in the carboxyl-terminal tail of rat AQP2. Here, we used phospho-specific antibodies and protein mass spectrometry to investigate the roles of vasopressin and cyclic AMP in the regulation of phosphorylation at Ser269 and addressed the role of this site in AQP2 trafficking. The V2 receptor-specific vasopressin analog dDAVP increased Ser(P)269-AQP2 abundance more than 10-fold, but at a rate much slower than the corresponding increase in Ser256 phosphorylation. Vasopressin-mediated changes in phosphorylation at both sites were mimicked by cAMP addition and inhibited by protein kinase A (PKA) antagonists. In vitro kinase assays, however, demonstrated that PKA phosphorylates Ser256, but not Ser269. Phosphorylation of AQP2 at Ser269 did not occur when Ser256 was replaced by an unphosphorylatable amino acid, as seen in both S256L-AQP2 mutant mice and in Madin-Darby canine kidney cells expressing an S256A mutant, suggesting that Ser269 phosphorylation depends upon prior phosphorylation at Ser256. Immunogold electron microscopy localized Ser(P)269-AQP2 solely in the apical plasma membrane of rat collecting duct cells, in contrast to the other three phospho-forms (found in both apical plasma membrane and intracellular vesicles). Madin-Darby canine kidney cells expressing an S269D "phosphomimic" AQP2 mutant showed constitutive localization at the plasma membrane. The data support a model in which vasopressin-mediated phosphorylation of AQP2 at Ser269:(a) depends on prior PKA-mediated phosphorylation of Ser256 and (b) enhances apical plasma membrane retention of AQP2.
Collapse
Affiliation(s)
- Jason D. Hoffert
- NHLBI, National Institutes of Health,
Bethesda, Maryland 20892-1603, the Water and
Salt Research Center, University of Aarhus, Aarhus DK-8000, Denmark,
Applied Biosytems/MDS Sciex, Concord, Ontario
L4K 4V8, Canada, and the Department of Internal
Medicine, Washington University School of Medicine, St. Louis, Missouri
63110
| | - Robert A. Fenton
- NHLBI, National Institutes of Health,
Bethesda, Maryland 20892-1603, the Water and
Salt Research Center, University of Aarhus, Aarhus DK-8000, Denmark,
Applied Biosytems/MDS Sciex, Concord, Ontario
L4K 4V8, Canada, and the Department of Internal
Medicine, Washington University School of Medicine, St. Louis, Missouri
63110
| | - Hanne B. Moeller
- NHLBI, National Institutes of Health,
Bethesda, Maryland 20892-1603, the Water and
Salt Research Center, University of Aarhus, Aarhus DK-8000, Denmark,
Applied Biosytems/MDS Sciex, Concord, Ontario
L4K 4V8, Canada, and the Department of Internal
Medicine, Washington University School of Medicine, St. Louis, Missouri
63110
| | - Brigitte Simons
- NHLBI, National Institutes of Health,
Bethesda, Maryland 20892-1603, the Water and
Salt Research Center, University of Aarhus, Aarhus DK-8000, Denmark,
Applied Biosytems/MDS Sciex, Concord, Ontario
L4K 4V8, Canada, and the Department of Internal
Medicine, Washington University School of Medicine, St. Louis, Missouri
63110
| | - Dmitry Tchapyjnikov
- NHLBI, National Institutes of Health,
Bethesda, Maryland 20892-1603, the Water and
Salt Research Center, University of Aarhus, Aarhus DK-8000, Denmark,
Applied Biosytems/MDS Sciex, Concord, Ontario
L4K 4V8, Canada, and the Department of Internal
Medicine, Washington University School of Medicine, St. Louis, Missouri
63110
| | - Bradley W. McDill
- NHLBI, National Institutes of Health,
Bethesda, Maryland 20892-1603, the Water and
Salt Research Center, University of Aarhus, Aarhus DK-8000, Denmark,
Applied Biosytems/MDS Sciex, Concord, Ontario
L4K 4V8, Canada, and the Department of Internal
Medicine, Washington University School of Medicine, St. Louis, Missouri
63110
| | - Ming-Jiun Yu
- NHLBI, National Institutes of Health,
Bethesda, Maryland 20892-1603, the Water and
Salt Research Center, University of Aarhus, Aarhus DK-8000, Denmark,
Applied Biosytems/MDS Sciex, Concord, Ontario
L4K 4V8, Canada, and the Department of Internal
Medicine, Washington University School of Medicine, St. Louis, Missouri
63110
| | - Trairak Pisitkun
- NHLBI, National Institutes of Health,
Bethesda, Maryland 20892-1603, the Water and
Salt Research Center, University of Aarhus, Aarhus DK-8000, Denmark,
Applied Biosytems/MDS Sciex, Concord, Ontario
L4K 4V8, Canada, and the Department of Internal
Medicine, Washington University School of Medicine, St. Louis, Missouri
63110
| | - Feng Chen
- NHLBI, National Institutes of Health,
Bethesda, Maryland 20892-1603, the Water and
Salt Research Center, University of Aarhus, Aarhus DK-8000, Denmark,
Applied Biosytems/MDS Sciex, Concord, Ontario
L4K 4V8, Canada, and the Department of Internal
Medicine, Washington University School of Medicine, St. Louis, Missouri
63110
| | - Mark A. Knepper
- NHLBI, National Institutes of Health,
Bethesda, Maryland 20892-1603, the Water and
Salt Research Center, University of Aarhus, Aarhus DK-8000, Denmark,
Applied Biosytems/MDS Sciex, Concord, Ontario
L4K 4V8, Canada, and the Department of Internal
Medicine, Washington University School of Medicine, St. Louis, Missouri
63110
| |
Collapse
|
50
|
GDPD5 is a glycerophosphocholine phosphodiesterase that osmotically regulates the osmoprotective organic osmolyte GPC. Proc Natl Acad Sci U S A 2008; 105:11026-31. [PMID: 18667693 DOI: 10.1073/pnas.0805496105] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glycerophosphocholine (GPC) is an abundant osmoprotective renal medullary organic osmolyte. We previously found that its synthesis from phosphatidylcholine is catalyzed by tonicity-regulated activity of the phospholipase B, neuropathy target esterase. We also found that its degradation is catalyzed by glycerophosphocholine phosphodiesterase (GPC-PDE) activity and that elevating osmolality from 300 to 500 mosmol/kg by adding NaCl or urea, inhibits GPC-PDE activity, which contributes to the resultant increase of GPC. In the present studies we identify GDPD5 (glycerophosphodiester phosphodiesterase domain containing 5) as a GPC-PDE that is rapidly inhibited by high NaCl or urea. Recombinant GDPD5 colocalizes with neuropathy target esterase in the perinuclear region of HEK293 cells, and immuno-precipitated recombinant GDPD5 degrades GPC in vitro. The in vitro activity is reduced when the cells from which the GDPD5 is immuno-precipitated have been exposed to high NaCl or urea. In addition, high NaCl decreases mRNA abundance of GDPD5 via an increase of its degradation rate, although high urea does not. At 300 mosmol/kg siRNA knockdown of GDPD5 increases GPC in mouse inner medullary collecting duct-3 cells, and over expression of recombinant GDPD5 increases cellular GPC-PDE activity, accompanied by decreased GPC. We conclude that GDPD5 is a GPC-PDE that contributes to osmotic regulation of cellular GPC.
Collapse
|