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Blaustein MP, Hamlyn JM. Sensational site: the sodium pump ouabain-binding site and its ligands. Am J Physiol Cell Physiol 2024; 326:C1120-C1177. [PMID: 38223926 PMCID: PMC11193536 DOI: 10.1152/ajpcell.00273.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/22/2023] [Accepted: 01/10/2024] [Indexed: 01/16/2024]
Abstract
Cardiotonic steroids (CTS), used by certain insects, toads, and rats for protection from predators, became, thanks to Withering's trailblazing 1785 monograph, the mainstay of heart failure (HF) therapy. In the 1950s and 1960s, we learned that the CTS receptor was part of the sodium pump (NKA) and that the Na+/Ca2+ exchanger was critical for the acute cardiotonic effect of digoxin- and ouabain-related CTS. This "settled" view was upended by seven revolutionary observations. First, subnanomolar ouabain sometimes stimulates NKA while higher concentrations are invariably inhibitory. Second, endogenous ouabain (EO) was discovered in the human circulation. Third, in the DIG clinical trial, digoxin only marginally improved outcomes in patients with HF. Fourth, cloning of NKA in 1985 revealed multiple NKA α and β subunit isoforms that, in the rodent, differ in their sensitivities to CTS. Fifth, the NKA is a cation pump and a hormone receptor/signal transducer. EO binding to NKA activates, in a ligand- and cell-specific manner, several protein kinase and Ca2+-dependent signaling cascades that have widespread physiological effects and can contribute to hypertension and HF pathogenesis. Sixth, all CTS are not equivalent, e.g., ouabain induces hypertension in rodents while digoxin is antihypertensinogenic ("biased signaling"). Seventh, most common rodent hypertension models require a highly ouabain-sensitive α2 NKA and the elevated blood pressure is alleviated by EO immunoneutralization. These numerous phenomena are enabled by NKA's intricate structure. We have just begun to understand the endocrine role of the endogenous ligands and the broad impact of the ouabain-binding site on physiology and pathophysiology.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States
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2
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Tempone MH, Borges-Martins VP, César F, Alexandrino-Mattos DP, de Figueiredo CS, Raony Í, dos Santos AA, Duarte-Silva AT, Dias MS, Freitas HR, de Araújo EG, Ribeiro-Resende VT, Cossenza M, P. Silva H, P. de Carvalho R, Ventura ALM, Calaza KC, Silveira MS, Kubrusly RCC, de Melo Reis RA. The Healthy and Diseased Retina Seen through Neuron-Glia Interactions. Int J Mol Sci 2024; 25:1120. [PMID: 38256192 PMCID: PMC10817105 DOI: 10.3390/ijms25021120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
The retina is the sensory tissue responsible for the first stages of visual processing, with a conserved anatomy and functional architecture among vertebrates. To date, retinal eye diseases, such as diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa, glaucoma, and others, affect nearly 170 million people worldwide, resulting in vision loss and blindness. To tackle retinal disorders, the developing retina has been explored as a versatile model to study intercellular signaling, as it presents a broad neurochemical repertoire that has been approached in the last decades in terms of signaling and diseases. Retina, dissociated and arranged as typical cultures, as mixed or neuron- and glia-enriched, and/or organized as neurospheres and/or as organoids, are valuable to understand both neuronal and glial compartments, which have contributed to revealing roles and mechanisms between transmitter systems as well as antioxidants, trophic factors, and extracellular matrix proteins. Overall, contributions in understanding neurogenesis, tissue development, differentiation, connectivity, plasticity, and cell death are widely described. A complete access to the genome of several vertebrates, as well as the recent transcriptome at the single cell level at different stages of development, also anticipates future advances in providing cues to target blinding diseases or retinal dysfunctions.
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Affiliation(s)
- Matheus H. Tempone
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.H.T.); (F.C.); (D.P.A.-M.); (V.T.R.-R.)
| | - Vladimir P. Borges-Martins
- Department of Physiology and Pharmacology, Biomedical Institute and Program of Neurosciences, Federal Fluminense University, Niterói 24020-150, Brazil; (V.P.B.-M.); (A.A.d.S.); (M.C.); (R.C.C.K.)
| | - Felipe César
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.H.T.); (F.C.); (D.P.A.-M.); (V.T.R.-R.)
| | - Dio Pablo Alexandrino-Mattos
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.H.T.); (F.C.); (D.P.A.-M.); (V.T.R.-R.)
| | - Camila S. de Figueiredo
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
| | - Ícaro Raony
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (Í.R.); (H.R.F.)
| | - Aline Araujo dos Santos
- Department of Physiology and Pharmacology, Biomedical Institute and Program of Neurosciences, Federal Fluminense University, Niterói 24020-150, Brazil; (V.P.B.-M.); (A.A.d.S.); (M.C.); (R.C.C.K.)
| | - Aline Teixeira Duarte-Silva
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
| | - Mariana Santana Dias
- Laboratory of Gene Therapy and Viral Vectors, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.S.D.); (H.P.S.)
| | - Hércules Rezende Freitas
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil; (Í.R.); (H.R.F.)
| | - Elisabeth G. de Araújo
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
- National Institute of Science and Technology on Neuroimmunomodulation—INCT-NIM, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro 21040-360, Brazil
| | - Victor Tulio Ribeiro-Resende
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.H.T.); (F.C.); (D.P.A.-M.); (V.T.R.-R.)
| | - Marcelo Cossenza
- Department of Physiology and Pharmacology, Biomedical Institute and Program of Neurosciences, Federal Fluminense University, Niterói 24020-150, Brazil; (V.P.B.-M.); (A.A.d.S.); (M.C.); (R.C.C.K.)
| | - Hilda P. Silva
- Laboratory of Gene Therapy and Viral Vectors, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.S.D.); (H.P.S.)
| | - Roberto P. de Carvalho
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
| | - Ana L. M. Ventura
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
| | - Karin C. Calaza
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói 24020-141, Brazil; (C.S.d.F.); (A.T.D.-S.); (E.G.d.A.); (R.P.d.C.); (A.L.M.V.); (K.C.C.)
| | - Mariana S. Silveira
- Laboratory for Investigation in Neuroregeneration and Development, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil;
| | - Regina C. C. Kubrusly
- Department of Physiology and Pharmacology, Biomedical Institute and Program of Neurosciences, Federal Fluminense University, Niterói 24020-150, Brazil; (V.P.B.-M.); (A.A.d.S.); (M.C.); (R.C.C.K.)
| | - Ricardo A. de Melo Reis
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21949-000, Brazil; (M.H.T.); (F.C.); (D.P.A.-M.); (V.T.R.-R.)
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3
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Interleukin-4 activates divergent cell-intrinsic signals to regulate retinal cell proliferation induced by classical growth factors. Mol Cell Neurosci 2022; 123:103780. [PMID: 36108809 DOI: 10.1016/j.mcn.2022.103780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 08/14/2022] [Accepted: 09/07/2022] [Indexed: 12/30/2022] Open
Abstract
In the developing retina, precise coordination of cell proliferation, differentiation, and survival is essential for proper retinal maturation and function. We have previously reported evidence that interleukin-4 (IL-4) plays critical roles in neuronal differentiation and survival during retinal development. However, little is known about the role of IL-4 on retinal cell proliferation. In the current study, we investigated if IL-4 regulates cell proliferation induced by epidermal growth factor (EGF) and by fibroblast growth factor 2 (FGF2) in primary retinal cell cultures obtained from newborn rats. First, we show that EGF and FGF2 act as mitogens for glial cells, increasing proliferation of these cells in the retina. EGF- and FGF2-induced mitogenesis requires activation of distinct cell-intrinsic signals. In retinal cells exposed to FGF2, IL-4 downregulates p53 levels (a protein whose activation induces cell-cycle arrest) and increases mitogenic responsiveness to FGF2 through activation of protein kinase A (PKA) pathway. Conversely, in retinal cells exposed to EGF, IL-4 downregulates cyclin D1 levels (a protein required for cell-cycle progression), upregulates p53 levels, and decreases mitogenic responsiveness to EGF. The inhibitory effect induced by IL-4 on retinal cells exposed to EGF requires activation of Janus kinase 3 (JAK3), but not activation of PKA. Based on previous and current findings, we propose that IL-4 serves as a node of signal divergence, modulating multiple cell-intrinsic signals (e.g., cyclin D1, p53, JAK3, and PKA) and mitogenic responsiveness to cell-extrinsic signals (e.g., FGF2 and EGF) to control cell proliferation, differentiation, and survival during retinal development.
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Kinoshita PF, Orellana AM, Andreotti DZ, de Souza GA, de Mello NP, de Sá Lima L, Kawamoto EM, Scavone C. Consequences of the Lack of TNFR1 in Ouabain Response in the Hippocampus of C57BL/6J Mice. Biomedicines 2022; 10:biomedicines10112937. [PMID: 36428505 PMCID: PMC9688030 DOI: 10.3390/biomedicines10112937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 11/17/2022] Open
Abstract
Ouabain is a cardiac glycoside that has a protective effect against neuroinflammation at low doses through Na+/K+-ATPase signaling and that can activate tumor necrosis factor (TNF) in the brain. TNF plays an essential role in neuroinflammation and regulates glutamate receptors by acting on two different receptors (tumor necrosis factor receptor 1 [TNFR1] and TNFR2) that have distinct functions and expression. The activation of constitutively and ubiquitously expressed TNFR1 leads to the expression of pro-inflammatory cytokines. Thus, this study aimed to elucidate the effects of ouabain in a TNFR1 knockout (KO) mouse model. Interestingly, the hippocampus of TNFR1 KO mice showed a basal increase in both TNFR2 membrane expression and brain-derived neurotrophic factor (BDNF) release, suggesting a compensatory mechanism. Moreover, ouabain activated TNF-α-converting enzyme/a disintegrin and metalloprotease 17 (TACE/ADAM17), decreased N-methyl-D-aspartate (NMDA) receptor subunit 2A (NR2A) expression, and induced anxiety-like behavior in both genotype animals, independent of the presence of TNFR1. However, ouabain induced an increase in interleukin (IL)-1β in the hippocampus, a decrease in IL-6 in serum, and an increase in NMDA receptor subunit 1 (NR1) only in wild-type (WT) mice, indicating that TNFR1 or TNFR2 expression may be important for some effects of ouabain. Collectively, our results indicate a connection between ouabain signaling and TNFR1, with the effect of ouabain partially dependent on TNFR1.
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Affiliation(s)
- Paula Fernanda Kinoshita
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Ana Maria Orellana
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Diana Zukas Andreotti
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Giovanna Araujo de Souza
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Natalia Prudente de Mello
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Larissa de Sá Lima
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Elisa Mitiko Kawamoto
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Cristoforo Scavone
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Correspondence:
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Mázala-de-Oliveira T, de Figueiredo CS, de Rezende Corrêa G, da Silva MS, Miranda RL, de Azevedo MA, Cossenza M, Dos Santos AA, Giestal-de-Araujo E. Ouabain-Na +/K +-ATPase Signaling Regulates Retinal Neuroinflammation and ROS Production Preventing Neuronal Death by an Autophagy-Dependent Mechanism Following Optic Nerve Axotomy In Vitro. Neurochem Res 2022; 47:723-738. [PMID: 34783975 DOI: 10.1007/s11064-021-03481-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/02/2021] [Accepted: 11/05/2021] [Indexed: 12/25/2022]
Abstract
Ouabain is a classic Na+K+ATPase ligand and it has been described to have neuroprotective effects on neurons and glial cells at nanomolar concentrations. In the present work, the neuroprotective and immunomodulatory potential of ouabain was evaluated in neonatal rat retinal cells using an optic nerve axotomy model in vitro. After axotomy, cultured retinal cells were treated with ouabain (3 nM) at different periods. The levels of important inflammatory receptors in the retina such as TNFR1/2, TLR4, and CD14 were analyzed. We observed that TNFR1, TLR4, and CD14 were decreased in all tested periods (15 min, 45 min, 24 h, and 48 h). On the other hand, TNFR2 was increased after 24 h, suggesting an anti-inflammatory potential for ouabain. Moreover, we showed that ouabain also decreased Iba-1 (microglial marker) density. Subsequently, analyses of retrograde labeling of retinal ganglion cells (RGC) were performed after 48 h and showed that ouabain-induced RGC survival depends on autophagy. Using an autophagy inhibitor (3-methyladenine), we observed a complete blockage of the ouabain effect. Western blot analyses showed that ouabain increases the levels of autophagy proteins (LC3 and Beclin-1) coupled to p-CREB transcription factor and leads to autophagosome formation. Additionally, we found that the ratio of cleaved/pro-caspase-3 did not change after ouabain treatment; however, p-JNK density was enhanced. Also, ouabain decreased reactive oxygen species production immediately after axotomy. Taken together, our results suggest that ouabain controls neuroinflammation in the retina following optic nerve axotomy and promotes RGC neuroprotection through activation of the autophagy pathway.
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Affiliation(s)
- Thalita Mázala-de-Oliveira
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói, 24020-141, Brazil
- Souza Marques School of Medicine, Souza Marques Technical-Educational Foundation, Rio de Janeiro, 21310-310, Brazil
| | - Camila Saggioro de Figueiredo
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói, 24020-141, Brazil
| | - Gustavo de Rezende Corrêa
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói, 24020-141, Brazil
- Souza Marques School of Medicine, Souza Marques Technical-Educational Foundation, Rio de Janeiro, 21310-310, Brazil
| | - Mayra Santos da Silva
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói, 24020-141, Brazil
- Souza Marques School of Medicine, Souza Marques Technical-Educational Foundation, Rio de Janeiro, 21310-310, Brazil
| | - Renan Lyra Miranda
- Department of Physiology and Pharmacology and Program of Neurosciences, Laboratory of Neurochemical I`nteractions & Laboratory of Molecular Pharmacology, Biomedical Institute, Federal Fluminense University, Niterói, 24020-141, Brazil
| | - Mariana Almeida de Azevedo
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói, 24020-141, Brazil
| | - Marcelo Cossenza
- Department of Physiology and Pharmacology and Program of Neurosciences, Laboratory of Neurochemical I`nteractions & Laboratory of Molecular Pharmacology, Biomedical Institute, Federal Fluminense University, Niterói, 24020-141, Brazil
| | - Aline Araujo Dos Santos
- Department of Physiology and Pharmacology and Program of Neurosciences, Laboratory of Neurochemical I`nteractions & Laboratory of Molecular Pharmacology, Biomedical Institute, Federal Fluminense University, Niterói, 24020-141, Brazil
| | - Elizabeth Giestal-de-Araujo
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Federal Fluminense University, Niterói, 24020-141, Brazil.
- National Institute of Science and Technology on Neuroimmunomodulation - INCT-NIM, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, 21040-360, Brazil.
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Cavalcante-Silva LHA, Carvalho DCM, de Almeida Lima É, Rodrigues-Mascarenhas S. Ouabain inhibits p38 activation in mice neutrophils. Inflammopharmacology 2021; 29:1829-1833. [PMID: 34792671 PMCID: PMC8600101 DOI: 10.1007/s10787-021-00882-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/10/2021] [Indexed: 12/28/2022]
Abstract
Ouabain is a cardiac steroid hormone with immunomodulatory effects. It inhibits neutrophils migration induced by different stimuli, but little is known about the mechanisms involved in this effect. Thus, the aim of this study was to evaluate the ouabain effect on chemotactic signaling pathways in neutrophils. For that, mice neutrophils were isolated from bone marrow, treated with ouabain (1, 10, and 100 nM) for 2 h, submitted to transwell chemotaxis assay and flow cytometry analysis of Akt, ERK, JNK, and p38 phosphorylation induced by zymosan. Ouabain treatment (1, 10 and, 100 nM) reduces neutrophil chemotaxis induced by chemotactic peptide fMLP, but this substance did not inhibit Akt, ERK, and JNK activation induced by zymosan. However, ouabain (1 and 10 nM) reduced p38 phosphorylation in zymosan-stimulated neutrophils. These results suggest that ouabain may interfere in neutrophil migration through p38 MAPK inhibition.
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Affiliation(s)
| | | | - Éssia de Almeida Lima
- Immunobiotechnology Laboratory, Biotechnology Center, Federal University of Paraíba, João Pessoa, 58051‑900, Brazil
| | - Sandra Rodrigues-Mascarenhas
- Immunobiotechnology Laboratory, Biotechnology Center, Federal University of Paraíba, João Pessoa, 58051‑900, Brazil.
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Increased Retinal Ganglion Cell Survival by Exogenous IL-2 Depends on IL-10, Dopamine D1 Receptors, and Classical IL-2/IL-2R Signaling Pathways. Neurochem Res 2021; 46:1701-1716. [PMID: 33792824 DOI: 10.1007/s11064-021-03313-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/01/2021] [Accepted: 03/24/2021] [Indexed: 10/21/2022]
Abstract
Interleukin-2 (IL-2) is a classical pro-inflammatory cytokine known to display neuroprotective roles in the central nervous system including the retina. In the present study, we investigate the molecular targets involved in the neurotrophic effect of IL-2 on retinal ganglion cells (RGC) after optic nerve axotomy. Analysis of retrograde labeling of RGC showed that common cell survival mediators, as Trk receptors, Src, PI3K, PKC, and intracellular calcium do not mediate the neurotrophic effect of IL-2 on RGC. No involvement of MAPK p38 was also observed. However, other MAPKs as MEK and JNK appear to be mediating this IL-2 effect. Our data also indicate that JAK2/3 are important intracellular proteins for the IL-2 effect. Interestingly, we demonstrate that the IL-2 effect depends on dopamine D1 receptors (D1R), the cAMP/PKA pathway, interleukin-10 (IL-10), and NF-κB, suggesting that RGC survival induced by IL-2 encompasses a molecular network of major complexity. In addition, treatment of retinal cells with recombinant IL-10 or 6-Cl-pb (D1R full agonist) was able to increase RGC survival similar to IL-2. Taken together, our results suggest that after optic nerve axotomy, the increase in RGC survival triggered by IL-2 is mediated by IL-10 and D1R along with the intracellular pathways of MAPKs, JAK/STAT, and cAMP/PKA.
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Buzaglo N, Golomb M, Rosen H, Beeri R, Ami HCB, Langane F, Pierre S, Lichtstein D. Augmentation of Ouabain-Induced Increase in Heart Muscle Contractility by Akt Inhibitor MK-2206. J Cardiovasc Pharmacol Ther 2018; 24:78-89. [DOI: 10.1177/1074248418788301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cardiac steroids (CSs), such as ouabain and digoxin, increase the force of contraction of heart muscle and are used for the treatment of congestive heart failure (CHF). However, their small therapeutic window limits their use. It is well established that Na+, K+-ATPase inhibition mediates CS-induced increase in heart contractility. Recently, the involvement of intracellular signal transduction was implicated in this effect. The aim of the present study was to test the hypothesis that combined treatment with ouabain and Akt inhibitor (MK-2206) augments ouabain-induced inotropy in mammalian models. We demonstrate that the combined treatment led to an ouabain-induced increase in contractility at concentrations at which ouabain alone was ineffective. This was shown in 3 experimental systems: neonatal primary rat cardiomyocytes, a Langendorff preparation, and an in vivo myocardial infarction induced by left anterior descending coronary artery (LAD) ligation. Furthermore, cell viability experiments revealed that this treatment protected primary cardiomyocytes from MK-2206 toxicity and in vivo reduced the size of scar tissue 10 days post-LAD ligation. We propose that Akt activity imposes a constant inhibitory force on muscle contraction, which is attenuated by low concentrations of MK-2206, resulting in potentiation of the ouabain effect. This demonstration of the increase in the CS effect advocates the development of the combined treatment in CHF.
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Affiliation(s)
- Nahum Buzaglo
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Mordechai Golomb
- The Heart Institute, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Haim Rosen
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Ronen Beeri
- The Heart Institute, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Hagit Cohen-Ben Ami
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Fattal Langane
- Marshall Institute for Interdisciplinary Research, Huntington, WV, USA
| | - Sandrine Pierre
- Marshall Institute for Interdisciplinary Research, Huntington, WV, USA
| | - David Lichtstein
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University Hadassah Medical School, Jerusalem, Israel
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Lopachev AV, Lopacheva OM, Osipova EA, Vladychenskaya EA, Smolyaninova LV, Fedorova TN, Koroleva OV, Akkuratov EE. Ouabain-induced changes in MAP kinase phosphorylation in primary culture of rat cerebellar cells. Cell Biochem Funct 2017; 34:367-77. [PMID: 27338714 DOI: 10.1002/cbf.3199] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 05/21/2016] [Accepted: 05/23/2016] [Indexed: 02/06/2023]
Abstract
Cardiotonic steroid (CTS) ouabain is a well-established inhibitor of Na,K-ATPase capable of inducing signalling processes including changes in the activity of the mitogen activated protein kinases (MAPK) in various cell types. With increasing evidence of endogenous CTS in the blood and cerebrospinal fluid, it is of particular interest to study ouabain-induced signalling in neurons, especially the activation of MAPK, because they are the key kinases activated in response to extracellular signals and regulating cell survival, proliferation and apoptosis. In this study we investigated the effect of ouabain on the level of phosphorylation of three MAPK (ERK1/2, JNK and p38) and on cell survival in the primary culture of rat cerebellar cells. Using Western blotting we described the time course and concentration dependence of phosphorylation for ERK1/2, JNK and p38 in response to ouabain. We discovered that ouabain at a concentration of 1 μM does not cause cell death in cultured neurons while it changes the phosphorylation level of the three MAPK: ERK1/2 is phosphorylated transiently, p38 shows sustained phosphorylation, and JNK is dephosphorylated after a long-term incubation. We showed that ERK1/2 phosphorylation increase does not depend on ouabain-induced calcium increase and p38 activation. Changes in p38 phosphorylation, which is independent from ERK1/2 activation, are calcium dependent. Changes in JNK phosphorylation are calcium dependent and also depend on ERK1/2 and p38 activation. Ten-micromolar ouabain leads to cell death, and we conclude that different effects of 1-μM and 10-μM ouabain depend on different ERK1/2 and p38 phosphorylation profiles. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Alexander V Lopachev
- Research Center of Neurology, Moscow, Russia.,Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Olga M Lopacheva
- Research Center of Neurology, Moscow, Russia.,Lomonosov Moscow State University, International Biotechnological Center, Moscow, Russia
| | - Ekaterina A Osipova
- Lomonosov Moscow State University, International Biotechnological Center, Moscow, Russia.,Lomonosov Moscow State University, Faculty of Chemistry, Department of Chemical Enzymology, Moscow, Russia
| | | | - Larisa V Smolyaninova
- Lomonosov Moscow State University, International Biotechnological Center, Moscow, Russia.,Lomonosov Moscow State University, Faculty of Biology, Department of Biochemistry, Moscow, Russia
| | | | - Olga V Koroleva
- Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Evgeny E Akkuratov
- St. Petersburg State University, Institute of Translational Biomedicine, St. Petersburg, Russia
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10
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Lima DB, Valente RC, Capella MAM. Ouabain-induced alterations in ABCB1 of mesenteric lymph nodes and thymocytes of rats and mice. Oncol Lett 2017; 12:5275-5280. [PMID: 28105236 DOI: 10.3892/ol.2016.5366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 06/27/2016] [Indexed: 11/06/2022] Open
Abstract
Ouabain is a glycoside with immunomodulating properties, and recent studies have suggested its use in adjuvant therapy for cancer treatment. Ouabain is known to modulate the immune system in vitro, and previous studies have revealed that ouabain can modulate the expression and activity of ABCB1, a protein associated with multidrug resistance present in immune system. Therefore, the present study investigated alterations in the expression and activity of ABCB1 in the thymi, peripheral blood monocytes and lymph nodes of Wistar rats and Swiss mice treated acutely or chronically with ouabain. A decrease of almost 45% in the monocyte count and an increase of 55% in the basophil count were observed. A significant decrease (75% reduction) in the amount of cells with ABCB1 activity was found in the thymocytes of ouabain-treated rats and mice. The possible implications of these results for cancer treatment are discussed.
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Affiliation(s)
- Daniel Boff Lima
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21949-900, Brazil
| | - Raphael Carmo Valente
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21949-900, Brazil
| | - Marcia Alves Marques Capella
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21949-900, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21949-900, Brazil
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11
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Salles von-Held-Ventura J, Mázala-de-Oliveira T, Cândida da Rocha Oliveira A, Granja MG, Gonçalves-de-Albuquerque CF, Castro-Faria-Neto HC, Giestal-de-Araujo E. The trophic effect of ouabain on retinal ganglion cells is mediated by IL-1β and TNF-α. Biochem Biophys Res Commun 2016; 478:378-384. [DOI: 10.1016/j.bbrc.2016.07.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 07/08/2016] [Indexed: 12/28/2022]
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12
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Aperia A, Akkuratov EE, Fontana JM, Brismar H. Na+-K+-ATPase, a new class of plasma membrane receptors. Am J Physiol Cell Physiol 2016; 310:C491-5. [PMID: 26791490 DOI: 10.1152/ajpcell.00359.2015] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Na(+)-K(+)-ATPase (NKA) differs from most other ion transporters, not only in its capacity to maintain a steep electrochemical gradient across the plasma membrane, but also as a receptor for a family of cardiotonic steroids, to which ouabain belongs. Studies from many groups, performed during the last 15 years, have demonstrated that ouabain, a member of the cardiotonic steroid family, can activate a network of signaling molecules, and that NKA will also serve as a signal transducer that can provide a feedback loop between NKA and the mitochondria. This brief review summarizes the current knowledge and controversies with regard to the understanding of NKA signaling.
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Affiliation(s)
- Anita Aperia
- Science for Life Laboratory, Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden; and
| | - Evgeny E Akkuratov
- Science for Life Laboratory, Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden; and
| | - Jacopo Maria Fontana
- Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
| | - Hjalmar Brismar
- Science for Life Laboratory, Department of Women and Children's Health, Karolinska Institutet, Stockholm, Sweden; and Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
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13
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Garcia IJP, Kinoshita PF, Scavone C, Mignaco JA, de Oliveira Barbosa LA, de Lima Santos H. Ouabain Modulates the Lipid Composition of Hippocampal Plasma Membranes from Rats with LPS-induced Neuroinflammation. J Membr Biol 2015; 248:1191-8. [DOI: 10.1007/s00232-015-9840-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 09/04/2015] [Indexed: 12/21/2022]
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14
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de Rezende Corrêa G, Soares VHP, de Araújo-Martins L, Dos Santos AA, Giestal-de-Araujo E. Ouabain and BDNF Crosstalk on Ganglion Cell Survival in Mixed Retinal Cell Cultures. Cell Mol Neurobiol 2015; 35:651-60. [PMID: 25651946 DOI: 10.1007/s10571-015-0160-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/27/2015] [Indexed: 12/27/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is a well-known and well-studied neurotrophin. Most biological effects of BDNF are mediated by the activation of TrkB receptors. This neurotrophin regulates several neuronal functions as cell proliferation, viability, and differentiation. Ouabain is a steroid that binds to the Na(+)/K(+) ATPase, inducing the activation of several intracellular signaling pathways. Previous data from our group described that ouabain treatment increases retinal ganglion cells survival (RGC). The aim of the present study was to evaluate, if this cardiac glycoside can have a synergistic effect with BDNF, the classical trophic factor for retinal ganglion cells, as well as investigate the intracellular signaling pathways involved. Our work demonstrated that the activation of Src, PLC, and PKCδ participates in the signaling cascade mediated by 50 ng/mL BDNF, since their selective inhibitors completely blocked the trophic effect of BDNF. We also demonstrated a synergistic effect on RGC survival when we concomitantly used ouabain (0.75 nM) and BDNF (10 ng/mL). Moreover, the signaling pathways involved in this synergistic effect include Src, PLC, PKCδ, and JNK. Our results suggest that the synergism between ouabain and BDNF occurs through the activation of the Src pathway, JNK, PLC, and PKCδ.
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Affiliation(s)
- Gustavo de Rezende Corrêa
- Departamento de Neurobiologia, Programa de Neurociências, Instituto de Biologia, Universidade Federal Fluminense, Outeiro de São João Batista s/n, Niterói, Rio de Janeiro, CEP 24020-140, Brazil,
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15
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The influence of Ouabain on human dendritic cells maturation. Mediators Inflamm 2014; 2014:494956. [PMID: 25609892 PMCID: PMC4291013 DOI: 10.1155/2014/494956] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Accepted: 12/01/2014] [Indexed: 11/17/2022] Open
Abstract
Although known as a Na,K-ATPase inhibitor, several other cellular and systemic actions have been ascribed to the steroid Ouabain (Oua). Particularly in the immune system, our group showed that Ouabain acts on decreasing lymphocyte proliferation, synergizing with glucocorticoids in spontaneous thymocyte apoptosis, and also lessening CD14 expression and blocking CD16 upregulation on human monocytes. However, Ouabain effects on dendritic cells (DCs) were not explored so far. Considering the peculiar plasticity and the importance of DCs in immune responses, the aim of our study was to investigate DC maturation under Ouabain influence. To generate immature DCs, human monocytes were cultured with IL-4 and GM-CSF (5 days). To investigate Ouabain role on DC activation, DCs were stimulated with TNF-α for 48 h in the presence or absence of Ouabain. TNF-induced CD83 expression and IL-12 production were abolished in DCs incubated with 100 nM Ouabain, though DC functional capacity concerning lymphocyte activation remained unaltered. Nevertheless, TNF-α-induced antigen capture downregulation, another maturation marker, occurred even in the presence of Ouabain. Besides, Ouabain increased HLA-DR and CD86 expression, whereas CD80 expression was maintained. Collectively, our results suggest that DCs respond to Ouabain maturating into a distinct category, possibly contributing to the balance between immunity and tolerance.
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16
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Dvela-Levitt M, Ami HCB, Rosen H, Shohami E, Lichtstein D. Ouabain improves functional recovery following traumatic brain injury. J Neurotrauma 2014; 31:1942-7. [PMID: 25007121 DOI: 10.1089/neu.2014.3544] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The cardiac steroid ouabain binds to Na(+), K(+)-ATPase and inhibits its activity. Administration of the compound to animals and humans causes an increase in the force of contraction of heart muscle and stabilizes heart rate. In addition, this steroid promotes the growth of cardiac, vascular, and neuronal cells both in vitro and in vivo. We studied the effects of ouabain on mouse recovery following closed head injury (CHI), a model for traumatic brain injury. We show that chronic (three times a week), but not acute, intraperitoneal administration of a low dose (1 μg/kg) of ouabain significantly improves mouse recovery and functional outcome. The improvement in mouse performance was accompanied by a decrease in lesion size, estimated 43 d following the trauma. In addition, mice that underwent CHI and were treated with ouabain showed an increase in the number of proliferating cells in the subventricular zone and in the area surrounding the site of injury. Determination of the identity of the proliferating cells in the area surrounding the trauma showed that whereas there was no change in the proliferation of endothelial cells or astrocytes, neuronal cell proliferation almost doubled in the ouabain-treated mice in comparison with that of the vehicle animals. These results point to a neuroprotective effects of low doses of ouabain and imply its involvement in brain recovery and neuronal regeneration. This suggests that ouabain and maybe other cardiac steroids may be used for the treatment of traumatic brain injury.
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Affiliation(s)
- Moran Dvela-Levitt
- 1 Department of Medical Neurobiology, The Hebrew University-Hadassah Medical School , Jerusalem, Israel
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17
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The (Na(+)/K (+))-ATPase activity in the developing rat retina: the role of insulin-like growth factor-I (IGF-I). Cell Mol Neurobiol 2014; 35:243-54. [PMID: 25274047 DOI: 10.1007/s10571-014-0119-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 09/23/2014] [Indexed: 02/04/2023]
Abstract
In this work, the (Na(+)/K(+))-ATPase activity was evaluated during the early stages of the postnatal development of rat retina and showed an almost three-time increase from P0 to P14. Expression of the three catalytic subunit isoforms (α1, α2, and α3) of the (Na(+)/K(+))-ATPase was also evaluated by immunoblot in the same period, but no correlation to the catalytic activity increment was observed. On the other hand, immunolocalization of these three α-catalytic isoforms in the developing retina showed an age-related pattern. Involvement of IGF-I in the stimulation of the (Na(+)/K(+))-ATPase was investigated. Our results demonstrate that the exogenous IGF-I (10 ng/mL) stimulates enzyme activity at the age of P7 only. Incubation of retinas with 10 μM I-OMe-AG 538 (inhibitor of the IGF-I receptor) indicates that the basal (Na(+)/K(+))-ATPase activity is sustained by endogenous IGF-I in P7 animals. These data were corroborated by an age-dependent decrease in the immunodetection of endogenous IGF-I as well as in the phosphorylation level of its cognate receptor in rat retina homogenates. The signaling pathway involved in IGF-I-induced modulation of the (Na(+)/K(+))-ATPase was also investigated. Our data show that the inhibitory effects induced by I-OMe-AG 538 and the PI 3-kinase inhibitor Ly 294002 on the basal (Na(+)/K(+))-ATPase activity were non-cumulative. Furthermore, IGF-I induced phosphorylation of PKB in a Ly 294002-sensitive manner. Together, these data demonstrate that the PI 3-kinase/PKB signaling pathway is involved in the IGF-I-sustained basal (Na(+)/K(+))-ATPase activity during the first 7 days of the postnatal development of rat retina.
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18
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de Souza WF, Barbosa LA, Liu L, de Araujo WM, de-Freitas-Junior JCM, Fortunato-Miranda N, Fontes CFL, Morgado-Díaz JA. Ouabain-induced alterations of the apical junctional complex involve α1 and β1 Na,K-ATPase downregulation and ERK1/2 activation independent of caveolae in colorectal cancer cells. J Membr Biol 2013; 247:23-33. [PMID: 24186357 DOI: 10.1007/s00232-013-9607-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 10/14/2013] [Indexed: 12/22/2022]
Abstract
Studies have reported that Na,K-ATPase interacts with E-cadherin to stabilize (AJs) and regulate the expression of claudins, the main proteins present in the tight junction (TJ) in epithelial cells containing caveolae. However, the role of this ATPase in the regulation of the AJ and TJ proteins in colorectal cancer cells as well as the molecular events underlying this event in a caveolae-independent system remain undefined. In the present study, we used ouabain, a classic drug known to inhibit Na,K-ATPase, and Caco-2 cells, which are a well-established human colorectal cancer model that does not exhibit caveolae. We demonstrated that ouabain treatment resulted in a reduction of the β1 Na,K-ATPase protein and cell redistribution of the AJ proteins E-cadherin and β-catenin, as well as the α1 Na,K-ATPase subunit. Furthermore, ouabain increased claudin-3 protein levels, impaired the TJ barrier function and increased cell viability and proliferation during the early stages of treatment. Additionally, the observed ouabain-induced events were dependent on the activation of ERK1/2 signaling; but in contrast to previous studies, this signaling cascade was caveolae-independent. In conclusion, our findings strongly suggest that α1 and β1 Na,K-ATPase downregulation and ERK1/2 activation induced by ouabain are interlinked events that play an important role during cell-cell adhesion loss, which is an important step during the tumor progression of colorectal carcinomas.
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Affiliation(s)
- Waldemir Fernandes de Souza
- Programa de Biologia Celular, Centro de Pesquisas, Instituto Nacional de Câncer, Rua André Cavalcanti, 37, 5° andar, Rio de Janeiro, RJ, 20231-050, Brazil
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19
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Valente RC, Araujo EG, Rumjanek VM. Ouabain inhibits monocyte activation in vitro: prevention of the proinflammatory mCD14(+)/CD16(+) subset appearance and cell-size progression. J Exp Pharmacol 2012; 4:125-40. [PMID: 27186125 PMCID: PMC4863552 DOI: 10.2147/jep.s35507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Classically described as a potent inhibitor of the sodium-potassium adenosine triphosphatase enzyme, ouabain has been further shown to act as an effective immunomodulator in mammals. Recently, our group showed that this hormone downregulates membrane CD14 (mCD14) in human monocytes, though it is not known whether monocyte activation status could modify ouabain influence. Hence, we aimed to investigate ouabain effect during monocyte activation in vitro, analyzing mCD14, CD16 and CD69 expression in total monocytes after two periods of adhesion (2 hours and 24 hours) or in small and large monocyte subpopulations separately. Ouabain (100 nM) inhibited monocyte-size increase, characteristic of activation, only when added to cells immediately after 2 hours’ adhesion. Moreover, downregulation of both mCD14 and CD16 expression by ouabain was more effective in small monocytes and in cells after 2 hours’ adhesion. Since monocytes after 24 hours’ adhesion showed no lack of ouabain binding and no CD69 upregulation, it seems that ouabain is somehow incapable of triggering an appropriate cell-signaling induction once monocytes become activated. Furthermore, though p38 MAPK activation was crucial for the impairment in cell-size progression induced by ouabain, its inhibition did not alter ouabain-induced CD69 upregulation, suggesting that other molecules may participate in the response to this hormone by monocytes. Our data suggest that ouabain inhibits monocyte activation in vitro, preventing both cell-size increase and the appearance of the proinflammatory mCD14+/CD16+ subpopulation. Thus, the findings suggest that individuals suffering from disorders commonly associated with high ouabain plasma levels, like hypertension, may present defective monocyte activation under inflammation or infection.
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Affiliation(s)
- Raphael C Valente
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Elizabeth G Araujo
- Departamento de Neurobiologia, Universidade Federal Fluminense, Rio de Janeiro, Brazil
| | - Vivian M Rumjanek
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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20
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Weidemann H. "The Lower Threshold" phenomenon in tumor cells toward endogenous digitalis-like compounds: Responsible for tumorigenesis? J Carcinog 2012; 11:2. [PMID: 22438768 PMCID: PMC3307333 DOI: 10.4103/1477-3163.92999] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 12/01/2011] [Indexed: 02/06/2023] Open
Abstract
Since their first discovery as potential anti-cancer drugs decades ago, there is increasing evidence that digitalis-like compounds (DLC) have anti-tumor effects. Less is known about endogenous DLC (EDLC) metabolism and regulation. As stress hormones synthesized in and secreted from the adrenal gland, they likely take part in the hypothalamo-pituitary-adrenal (HPA) axis. In a previous study, we revealed reduced EDLC concentrations in plasma and organs from immune-compromised animals and proposed that a similar situation of a deregulated HPA axis with "adrenal EDLF exhaustion" may contribute to tumorigenesis in chronic stress situations. Here, we put forward the hypothesis that a lowered EDLC response threshold of tumor cells as compared with normal cells increases the risk of tumorigenesis, especially in those individuals with reduced EDLC plasma concentrations after chronic stress exposure. We will evaluate this hypothesis by (a) summarizing the effects of different DLC concentrations on tumor as compared with normal cells and (b) reviewing some essential differences in the Na/K-ATPase of tumor as compared with normal cells (isoform pattern, pump activity, mutations of other signalosome receptors). We will conclude that (1) tumor cells, indeed, seem to have their individual "physiologic" EDLC response range that already starts at pmolar levels and (2) that individuals with markedly reduced (pmolar) EDLC plasma levels are predisposed to cancer because these EDLC concentrations will predominantly stimulate the proliferation of tumor cells. Finally, we will summarize preliminary results from our department supporting this hypothesis.
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Affiliation(s)
- Heidrun Weidemann
- Department of Oncology, Hadassah-Hebrew University, Medical Center, Jerusalem, Israel
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21
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da Silva Cunha KC, Fuly AL, de Araujo EG. A phospholipase A₂ isolated from Lachesis muta snake venom increases the survival of retinal ganglion cells in vitro. Toxicon 2011; 57:580-5. [PMID: 21223976 DOI: 10.1016/j.toxicon.2010.12.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 12/08/2010] [Accepted: 12/30/2010] [Indexed: 12/31/2022]
Abstract
We have previously showed that a phospholipase A₂ isolated from Lachesis muta snake venom and named LM-PLA₂-I displayed particular biological activities, as hemolysis, inhibition on platelet aggregation, edema induction and myotoxicity. In the present work, we evaluated the effect of LM-PLA₂-I on the survival of axotomized rat retinal ganglion cells kept in vitro, as well as its mechanism of action. Our results clearly showed that treatment with LM-PLA₂-I increased the survival of ganglion cells (100% when compared to control cultures) and the treatment of LM-PLA₂-I with p-bromophenacyl bromide abolished this effect. This result indicates that the effect of LM-PLA₂-I on ganglion cell survival is entirely dependent on its enzymatic activity and the generation of lysophosphatidylcholine (LPC) may be a prerequisite to the observed survival. In fact, commercial LPC mimicked the effect of LM-PLA₂-I upon ganglion cell survival. To investigate the mechanism of action of LM-PLA₂-I, cultures were treated with chelerythrine chloride, BAPTA-AM, rottlerin and also with an inhibitor of c-junc kinase (JNKi). Our results showed that rottlerin and JNK inhibitor abolished the LM-PLA₂-I on ganglion cell survival. Taken together, our results showed that LM-PLA₂-I and its enzymatic product, LPC promoted survival of retinal ganglion cells through the protein kinase C pathway and strongly suggest a possible role of the PLA₂ enzyme and LPC in controlling the survival of axotomized neuronal cells.
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Affiliation(s)
- Karinne Cristinne da Silva Cunha
- Programa de Pós-Graduação em Neurociências, Departamento de Neurobiologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brazil
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22
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Panayiotidis MI, Franco R, Bortner CD, Cidlowski JA. Ouabain-induced perturbations in intracellular ionic homeostasis regulate death receptor-mediated apoptosis. Apoptosis 2010; 15:834-49. [PMID: 20422450 DOI: 10.1007/s10495-010-0494-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Apoptosis is defined by specific morphological and biochemical characteristics including cell shrinkage (termed apoptotic volume decrease), a process that results from the regulation of ion channels and plasma membrane transporter activity. The Na(+)-K(+)-ATPase is the predominant pump that controls cell volume and plasma membrane potential in cells and alterations in its function have been suggested to be associated with apoptosis. We report here that the Na(+)-K(+)-ATPase inhibitor ouabain, potentiates apoptosis in the human lymphoma Jurkat cells exposed to Fas ligand (FasL) or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) but not other apoptotic agents such as H(2)O(2), thapsigargin or UV-C implicating a role for the Na(+)-K(+)-ATPase in death receptor-induced apoptosis. Interestingly, ouabain also potentiated perturbations in cell Ca(2+) homeostasis only in conjunction with the apoptotic inducer FasL but not TRAIL. Ouabain did not affect alterations in the intracellular Ca(2+) levels in response to H(2)O(2), thapsigargin or UV-C. FasL-induced alterations in Ca(2+) were not abolished in Ca(2+)-free medium but incubation of cells with BAPTA-AM inhibited both Ca(2+) perturbations and the ouabain-induced potentiation of FasL-induced apoptosis. Our data suggest that the impairment of the Na(+)-K(+)-ATPase activity during apoptosis is linked to perturbations in cell Ca(2+) homeostasis that modulate apoptosis induced by the activation of Fas by FasL.
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Affiliation(s)
- Mihalis I Panayiotidis
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health, Research Triangle Park, NC, 27709, USA.
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23
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de Rezende Corrêa G, da Silva Cunha KC, dos Santos AA, de Araujo EG. The Trophic Effect of Ouabain on Retinal Ganglion Cell is Mediated by EGF Receptor and PKC δ Activation. Neurochem Res 2010; 35:1343-52. [DOI: 10.1007/s11064-010-0190-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2010] [Indexed: 01/11/2023]
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Rodrigues-Mascarenhas S, Da Silva de Oliveira A, Amoedo ND, Affonso-Mitidieri OR, Rumjanek FD, Rumjanek VM. Modulation of the immune system by ouabain. Ann N Y Acad Sci 2009; 1153:153-63. [PMID: 19236338 DOI: 10.1111/j.1749-6632.2008.03969.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ouabain, a known inhibitor of the Na,K-ATPase, has been shown to regulate a number of lymphocyte functions in vitro and in vivo. Lymphocyte proliferation, apoptosis, cytokine production, and monocyte function are all affected by ouabain. The ouabain-binding site occurs at the alpha subunit of the enzyme. The alpha subunit plays a critical role in the transport process, and four different alpha-subunit isoforms have been described with different sensitivities to ouabain. Analysis by RT-PCR indicates that alpha1, alpha2, and alpha3 isoforms are all present in murine lymphoid cells obtained from thymus, lymph nodes, and spleen. In these cells ouabain exerts an effect at concentrations that do not induce plasma membrane depolarization, suggesting a mechanism independent of the classical inhibition of the pump. In other systems, the Na,K-ATPase acts as a signal transducer in addition to being an ion pump, and ouabain is capable of inducing the activation of various signal transduction cascades. Neither resting nor concanavalin A (Con A)-activated thymocytes had their levels of phosphorylated-extracellular signal-regulated kinase (P-ERK) modified by ouabain. However, ouabain decreased p38 phosphorylation induced by Con A in these cells. The pathway induced by ouabain in lymphoid cells is still unclear but might vary with the type and state of activation of the cell.
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Affiliation(s)
- Sandra Rodrigues-Mascarenhas
- Laboratório de Tecnologia Farmacêutica, Departamento de Fisiologia e Patologia, Universidade Federal da Paraíba, João Pessoa, Brazil
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